CA2253486A1 - Process and apparatus for treating leather and the like - Google Patents
Process and apparatus for treating leather and the like Download PDFInfo
- Publication number
- CA2253486A1 CA2253486A1 CA002253486A CA2253486A CA2253486A1 CA 2253486 A1 CA2253486 A1 CA 2253486A1 CA 002253486 A CA002253486 A CA 002253486A CA 2253486 A CA2253486 A CA 2253486A CA 2253486 A1 CA2253486 A1 CA 2253486A1
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- Prior art keywords
- container
- leather
- liquid solution
- pieces
- introduction
- Prior art date
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- Abandoned
Links
- 239000010985 leather Substances 0.000 title claims abstract description 191
- 238000000034 method Methods 0.000 title claims abstract description 72
- 230000008569 process Effects 0.000 title claims abstract description 57
- 239000006193 liquid solution Substances 0.000 claims abstract description 158
- 238000011282 treatment Methods 0.000 claims abstract description 70
- 238000002791 soaking Methods 0.000 claims abstract description 20
- 238000005554 pickling Methods 0.000 claims abstract description 19
- 239000000126 substance Substances 0.000 claims description 31
- 238000007599 discharging Methods 0.000 claims description 22
- 238000004043 dyeing Methods 0.000 claims description 20
- 238000005406 washing Methods 0.000 claims description 17
- 230000009471 action Effects 0.000 claims description 16
- 239000007788 liquid Substances 0.000 claims description 12
- 238000011084 recovery Methods 0.000 claims description 8
- 238000006386 neutralization reaction Methods 0.000 claims description 5
- 238000002604 ultrasonography Methods 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 4
- 150000001875 compounds Chemical class 0.000 claims description 3
- 239000000243 solution Substances 0.000 description 9
- 239000002699 waste material Substances 0.000 description 8
- 150000003839 salts Chemical class 0.000 description 7
- 239000003795 chemical substances by application Substances 0.000 description 4
- 239000011148 porous material Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 239000000460 chlorine Substances 0.000 description 3
- 229910052801 chlorine Inorganic materials 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- UKLNMMHNWFDKNT-UHFFFAOYSA-M sodium chlorite Chemical compound [Na+].[O-]Cl=O UKLNMMHNWFDKNT-UHFFFAOYSA-M 0.000 description 3
- 229960002218 sodium chlorite Drugs 0.000 description 3
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical class [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- 239000004150 EU approved colour Substances 0.000 description 2
- 102000004190 Enzymes Human genes 0.000 description 2
- 108090000790 Enzymes Proteins 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 239000003925 fat Substances 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 229940006093 opthalmologic coloring agent diagnostic Drugs 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 230000008961 swelling Effects 0.000 description 2
- 235000013311 vegetables Nutrition 0.000 description 2
- 239000003039 volatile agent Substances 0.000 description 2
- 241000518994 Conta Species 0.000 description 1
- 241001125620 Dermochelys coriacea Species 0.000 description 1
- 241001465754 Metazoa Species 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000031018 biological processes and functions Effects 0.000 description 1
- 159000000007 calcium salts Chemical class 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000002301 combined effect Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 239000000975 dye Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 102000004169 proteins and genes Human genes 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 235000019345 sodium thiosulphate Nutrition 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C14—SKINS; HIDES; PELTS; LEATHER
- C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
- C14C15/00—Apparatus for chemical treatment or washing of hides, skins, or leather
-
- C—CHEMISTRY; METALLURGY
- C14—SKINS; HIDES; PELTS; LEATHER
- C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
- C14C1/00—Chemical treatment prior to tanning
-
- C—CHEMISTRY; METALLURGY
- C14—SKINS; HIDES; PELTS; LEATHER
- C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
- C14C3/00—Tanning; Compositions for tanning
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Treatment And Processing Of Natural Fur Or Leather (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
- Cosmetics (AREA)
- Electrophonic Musical Instruments (AREA)
- Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
- Toys (AREA)
- Treatment Of Fiber Materials (AREA)
Abstract
According to the process of treating leather and the like, spread pieces of leather to be treated (1) are put on respective open supports (2). These supports (2), with spread pieces of leather carried thereon, are introduced into at least one container (4), kept in depression and sealed for the introduction therein of suitable treating liquid solutions so that at least soaking, liming, pickling, tanning and re-tanning steps can be performed on the leather pieces. Each liquid solution (5) is swirled during the corresponding leather (1) treatment step.
Description
CA 022~3486 1998-10-30 W O 97/42350 PCT~B97/00432 PROCESS AND APPARATUS FOR TREATING LEATHER AND THE LIKE
TECHNICAL FIELD
The present invention concerns tannage of leather and the like.
BACKGROUND ART
It is known that animal skin is tanned, so as not to putrefy, with solutions that remain irreversibly fixed thereon, turning it into hide.
This treatment includes different steps, which are often complex and requiring o relatively much time.
When delivered to tannery, generally dried with salts, rawhide is initially subjected to preparation for real tanning.
This preparation includes first a soaking step, i.e. removing impurities that cover both inner flesh side and outer or grain side, as well as preserving solutions, so as to bring the leather back to its natural softness.
The leather to be treated is soaked in drums containing suitable liquid solutions.
These drums are provided inside with immovable paddles or stakes, which act on the leather during drum rotation.
Therefore, the treatment consists of combined chemical action of the liquid solution and the mechanical action performed on the leather and lasts six to twenty four hours.
Afterwards, a fleshing step follows, with which the fat is removed from the soaked leather, and subsequently liming treatment follows for removing hair and reveal the derma.
Liming is performed in suitable drums with alkaline substances, such as sulphides or lime, which make the leather tissue swell and dissolve the hair roots.
More precisely, the leather swells up, the fats turn into calcium salts and proteins forming the leather are modified due to breaking of principal and secondary links of the proteic chains and, sl~hsequently, the hair detaches - from the leather.
The substances used for liming, and at the same time for "opening" the CA 022~3486 1998-10-30 leather pores in order to execute real tanning and dyeing, are highly polluting,which results in all known problems of waste disposal and/or purification.
Liming step requires usually twenty four hours.
Then, thus prepared leather is decalcined and bated, again in suitable drums.
s Due to decalcination step, usually with decalcinating salts, the retained lime is removed.
Bating is a biological action which softens leather grain by enzymes which partly dissolve elastic fibres, causing the leather relaxation.
Subsequently, the leather is subjected to pickling, i.e. treatment, which o guarantees more rapid and complete penetration of the tanning salts.
In fact, bated leather, having basic reaction, cannot be tanned with e.g.
tanning salts of chromium, because it would result in a chemical reaction, which would close the leather pores.
Therefore, the leather is acidified with small quantities of acid, with the presence of salts (usually sodium chloride) so as to prevent swelling. This step is performed in a drum and lasts an average of ten - twelve hours.
The real tanning treatment is carried out inside the aforementioned drums, by means of vegetable solutions, such as natural or synthetic tanning solutions, or by mineral salts, mainly chromium or the like salts.
The liming, bating, pickling and tanning steps altogether require an average of not less than forty eight hours (it can vary according to the type of the leather to be treated).
The tanned leather, suitably pressed to remove a part of absorbed water, selected and skived, is subjected to dyeing treatment, otherwise called re-tanning.
This dyeing step requires an average of eight hours.
Thus, the above mentioned tanning treatments require, as has been alreadysaid, much time, which can take an average of one week.
This results in the necessity for using a relatively big number of huge drums in3n order to achieve an adeqll~te productivity. The pieces of leather to be treated are thrown into the drums in bulk and are subjected directly to a mechanical action, which sometimes can damage them.
- A not minor disadvantage of traditional tanning processes derives from the fact that the working environment is very harmful, due mainly to miasma CA 022~3486 1998-10-30 W O 971423~0 PCT~B97/00432 produced by the aforementioned drums.
Moreover, there is a serious problem of disposal of liquids discharged at the end of the above mentioned treatments, in particular of the substances used for liming.
s SUMMARY OF THE INVENTION
The object of the present invention is to propose a process, that allows tanning treatments of leather and the like to be carried out in less time with respect to the known systems, and that, at the same time, guarantees the 10 high quality of tanned leather as well as high throughput, the whole being obtained with reduced quantity of required energy, with respect to known techniques.
Another principal object of the present invention is to propose a process that can be carried out by an apparatus, which allows to operate in a non-harmful 15 working environment, and which considerably reduces the problems connected with waste disposal.
Yet a further object of the present invention is to propose a process, which allows to reduce markedly a quantity of used substances with the same quality of tanned leather.
20 Still another object of the invention is to propose a process, whose carrying out does not pollute the air.
Moreover, the invention has another object of proposing an apparatus, which carries out the aforementioned method.
The above mentioned objects are obtained by a process of treatment of 2s leather and the like, which includes:
disposing spread pieces of leather to be treated, spaced apart, into a container;
introducing liquid solutions into said container, in sequence and with predetermined intervals, for pe, rvn"i"g various steps of leather tanning 30 treatment, said liquid solutions being discharged from the container, after each step has been completed;
maintaining deprt:ssion inside said container, at least for the duration of eachsingle step;
generating, during each step, a relative movement between the liquid solution CA 022~3486 1998-10-30 and said pieces of leather, so as to intensify the action of said liquid solution on said pieces of leather.
The process is carried out by means of an apparatus which includes:
a container to be closed tight;
5 a plurality of supports, which can be introduced and withdrawn from said container, and on which the corresponding spread pieces of leather are fastened, these supports being situated in said container in such a way as to keep said pieces of leather spaced out;
a hrst series of tanks containing predetermined liquid solutions for lo corresponding leather treatment steps;
on/off and control means which connect each of said tanks to the container so as to introduce therein the relative liquid solution for corresponding leather treatment step;
suction means for maintaining depression inside said container at least while 15 performing the leather treatment steps;
means for generating relative movement between a liquid solution and said pieces of leather so as to intensify the action of said liquid solution thereon.According to a different embodiment, the process includes:
disposing spread pieces of leather to be treated, spaced apart, into a first 20 container;
introducing liquid solution into said container for performing a step of leathertanning treatment;
maintaining depression inside said conta;ner during performing of said step;
generating, during said step, relative movement between the liquid solution 25 and said pieces of leather, so as to strengthen the action of said liquid solution on said pieces of leather;
discharging said liquid solution from said hrst collldi"er;
withdrawing said pieces of leather from the first container;
repeating the above mentioned operations in further containers so as to 30 perform remaining steps of the leather tanning treatment.
According to a different embodiment, the apparaLus includes:
a plurality of containers to be closed tight, inside which predetermined leathertreatment steps are carried out;
, , CA 022~3486 1998-10-30 a plurality of supports, which can be introduced and withdrawn from said ~ containers, and on which the corresponding spread pieces of leather are fastened, these supports being situated in said containers in such a way as to - keep spaced out said pieces of leather;
s a first series of tanks containing predetermined liquid solutions for corresponding leather treatment steps;
on/off and control means, which connect each of said tanks to the re~ative container so as to introduce therein the relative liquid solution for a corresponding leather treatment step;
lo suction means for maintaining depression inside each of said containers at least during performing therein of the relative leather treatment steps;
means for generating, inside each of said containers, relative movement between a corresponding liquid solution and said pieces of leather so as to intensify the action of said li~uid solution thereon.
15 Further characleristics and features are pointed out in the sub-claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The characteristic features of the invention will become pointed out in the following description, with particular reference to the enclosed drawings, in 20 which:
- fig. 1 shows a plan view of supporting means for a piece of leather to be treated;
- figs. 2a, 2b and 2c show schematic views of containers into which the above mentioned support means are ~lisposed, with different a"~nge"lents, 2s respectively;
- fig. 3 shows a schematic vertical section view of said container, during one step of the leather treatment;
- figs. 4a and 4b, show ~iayra"~s of apparatuses for carrying out corresponding tanning treatments accor li.,g to the method, being the subject 30 of the present invention;
- figs. 5a, 5b show diagrams of two different embodiments of the above mentioned apparatus, which carry the method in a different way;
- fig. 6 shows a possible diagram of an apparatus, which carries the method in a further way;
CA 022~3486 1998-10-30 W O 97/42350 PCT~B97/00432 -6-- Fig. 7 shows a further embodiment of the apparatus;
- Fig. 8, shows a constructive variation of the apparatus container;
- Figures 9a and 9b show two schematic diagrams of a facility for vapour recovey in both operation conditions.
s BEST MODES OF CARRYING OUT THE INVENTION
With reference to the above mentioned figures, numeral 1 indicates a piece of leather to be subjected to tanning treatment according to the subject process.
According to this process, the piece of leather to be treated 1 is spread on a l0 respective open support, e.g. frame 2 shown in fig. 1.
The piece of leather 1 is fastened to the frame 2 by a series of expanders 3 of known type.
The frames 2 supporting the spread pieces of leather 1 are introduced into a container 4, kept fixed according to preferred embodiment, which is to be s closed tight, for the treatment with a sl~it~h'E liquid solution introduced therein.
The frames 2 supporting the spread pieces of leather 1 are introduced into the container 4 preferably in vertical arrangement, regularly spaced apart, as seen in figure 2a.
Nevertheless, it is possible to arrange the frames 2 inside the container 4 horizontally (fig. 2b) or inclined (fig. 2c).
In case the pieces of leather are to be arranged vertically, it is sufficient tohang them on a suitable creel, not shown, so as to maintain them mutually spaced apart.
As shown as an example in fig. 3, the upper part of the container 4, which contains the treating liquid solution 5, is closed tight by a cover 6.
In its lower part, the container 4 has holder means 7 for the frames 2 supporting the pieces of leather 1.
Inside the container 4, there is also situated a heat exchanger 8, that heats the liquid solution 5 to the desired temperature. The liquid solution 5 inside the 30 container 4, is swirled during the treatment of the leather pieces 1 spread on the frames 2.
For this purpose, the container 4 features a deliver element 9, situated below the holder means 7 for the frames 2 and formed by a grate provided with a CA 022~3486 1998-10-30 W O 97/423~0 PCTnB97/00432 series of ejectors 10, which eject air in form of bubbles.
Inside the container 4, over the liquid solution 5, depression is maintained by suitable suction means 11 connected with the container by a pipe 110, passing through one of two neutralisation tanks 111a, 111b, which will be s described later. The advantage of keeping the container 4 in depression will be pointed out in the following.
Moreover, due to this depression, a flow of air is sucked from outside via the deliver element 9. Further, the depression reduces the quantity of energy consumed for reaching the desired working temperature. Otherwise, the 0 aforementioned flow of air can be obtained by suitable compression means, connected to the deliver element 9.
In the following, the same reference numbers will indicate means carrying out the same functions.
The apparatus for tanning treatments, shown in fig. 4a, includes a series of 5 tanks 12, preferably tight, containing liquid solutions to be supplied to the container 4 for the aforementioned treatments.
In particular, there are four tanks 12a,12b,12c,12d supplying liquid solutions used correspondingly for the soaking, liming, pickling and tanning steps.
When needed, during the tanning treatment the leather pieces are also dyed.
The tanks are provided with respective heat exchangers 13a, 13b, 13c, 13d which maintain the liquid solutions at desired temperatures. The heat exchangers 13a, 13b, 13c, 13d are controlled by a control unit 14 by connections indicated with S1, S2, S3 and S4.
The supply tanks are connected with respective jet pipes 15a, 15b, 15c and 2s 15d, equipped with related pumps 16a, 16b, 16c and 16d, controlled, in theirturn, by the control unit 14 through connections indicated with P1, P2, P3 and P4.
The jet pipes 15a, 15b, 15c and 15d are connected to an inlet pipe 17 of the container 4 by a valve means 18 which is controlled by the control unit 14.
The bottom of the container 4 features an outlet pipe 19, provided with a pump 20, controlled by the control unit 14.
The outlet pipe 19 is connected alternatively, by a valve means 21, with discharge pipes 22a, 22b, 22c and 22d, communicating with respective waste tanks 23a, 23b,23c and 23d of the liquid solutions used in the container 4.
The waste tanks 23 communicate with corresponding supply tanks 12 by CA 022~3486 1998-10-30 W 097/42350 PCT~B97/00432 means of respective return pipes 24a, 24b, 24c, 24d, equipped with respective pumps 25a, 25b, 25c, 25d, controlled by the control unit 14.
As an alternative constructive form, the discharge pipes 22a, 22b, 22c and 22d lead all to a unique manifold (which has not been shown) which is 5 connected to a suitable cleaner.
In practice, in order to perform each of the aforementioned tanning treatment steps, the container 4 is fed with the liquid solution taken from the relative supply tank 12.
According to a preferred embodiment, the apparatus includes also at least lO other two tanks 30a, 30b, containing washing liquid solutions, which will be described later, and provided with relative jet pipes 31, 31b, featuring relative pumps 32a, 32b controlled by the control unit 14.
These pipes are connected to an inlet duct 33 of the container 4 by a valve means 34 co"l,ollcd by the control unit 14.
S The aforementioned outlet pipe 19, connected to the bottom of the container 4, can be also connected, by the valve means 21, to one or the other of discharge pipes 35a, 35b, flowing into the tanks 30a, 30b, respectively.
Inside the container 4, the liquid solution is swirled by the air flow produced,as has been previously described, in the liquid solution.
20 It is to be pointed out that before each single step is carried out, more precisely, before the container is fed with liquid solution, depression is created therein so as to swell the leather making it spongy and thus facilitating the action of liquid solution thereon.
The above mentioned swirling causes a kind of massage on the leather 2s pieces, that replaces the mechanical action of known systems without damaging the leather.
When each of said treatment steps is completed, the used liquid solution is withdrawn from the container 4 and sent to the relative waste tank 23. After having been regenerated, by means of techniques which are well known by 30 those skilled in the art, this liquid solution can be let again into the corresponding supply tank 12, for a new tanning cycle.
The soaking treatment is carried out with the liquid solution contained in the tank 12a; water, possibly added with chemical promoters.
Due to depression, created before the liquid solution has been introduced, the 3s leather absorbs water more easily, since it tends to swell naturally, thus .. .. .
CA 022~3486 1998-10-30 becoming, as it has already been said, more spongy.
These factors, i.e. combined action of depression and swirling, reduce the time required for the soaking step.
When the soaking has been finished, the leather pieces are washed with 5 water contained in the tank 30a.
The liming treatment is performed with the liquid solution contained in the tank12b, according to oxidising method, e.g. by sodium chlorite or enzyme agents.
It is to be pointed out that sodium chlorite cannot be used in the liming step carried out in wooden drums, because it frees chlorine, which corrodes the l o wood .
Since pulled by the suction means 11 and freed through the pipe 110, chlorine enters one of the tanks 111a, 111b, which contains a solution of sodium hyposulphite, that, as it is known, neutralises chlorine. In this way, the suction means 11 are protected and the problem of disposal of substances used for 15 liming treatment, is resolved.
In the present case, the combined effect of depression, which swells the leather, of sodium chlorite and of massage performed on the leather by the swirled air, allows to carry out the liming treatment.
This is considerably advantageous for the following reasons:
20 - use of a substance, whose disposal (more precisely, neutralisation) is not very troublesome;
- due to depression in working environment, the consume of energy is reduced;
- the pieces of leather are not mechanically stressed.
2s It is also to be pointed out that the leather swelling makes also the pores open, which is advantageous for subsequent tanning and dyeing treatments.
The liming step requires about five hours. After having been limed, the leather is washed with the contents of the tank 30b.
The iiming step is followed by pickling step, which is carried out using the 30 con~ents of the tank 12c; the effect of this operation is intensified by the massage of the leather performed by the swirling.
The liquid solution contained in the tank 12d is used for the real tanning step and, when needed, for the dyeing step, the latter being performed by colouring agents (e.g. vegetable colouring agents) dispersed in the liquid CA 022~3486 1998-10-30 W O 97/42350 PCT~B97/00432 solution.
This liquid solution can also contain agents facilitating leather greasing. The time required for accomplishment of these steps is reduced because the pores remain open due to the depression effect. Also the quantity of tanning and dyeing substances is lower with respect to traditional methods.
In fact, in the described conditions, (i.e. Ieather swollen, thus more spongy), the concentration in the liquid solution of the tanning and dyeing agents, whichare transferred from the liquid solution to the leather (where they remain irreversibly fixed), is reduced with respect to known systems, therefore the o quantity of these agents is smaller, but the quality of the obtained result remains the same. The pickling, tanning and dyeing operations require about 24 - 36 hours.
It is known that the real tanning l,~l",ent can be preceded by the so-called pre-tanning and that dyeing (known also as re-tanning), carried out simultaneously with the agents for leather greasing, can be performed separately from and after the real tanning treatment.
The apparatus that carries out the above mentioned variants, is schematically shown in fig. 4b, where the numeral 12e indicates the tank containing the liquid pre-tanning products, 23e indicates the tank containing the waste liquid after the pre-tanning has been completed, 30d indicates the tank containing the solution for washing the leather after the pre-tanning has been completed, 12f indicates the tank with liquid solution for leather re-tanning and greasing and 23f indicates the tank, which receives waste from the container 4 after the last step has been completed.
Generally, it has been proved that the process, being the subject of the present invention, allows to carry out leather tanning in considerably reduced amount of time, with respect to the traditional techniques, guaranteeing at the same time a high quality of the tanned leather.
This result is helped also by spreading of leather on the frames 2, swirling 30 movement due to the air flow produced in the liquid solution 5, with which the - treatment is being carried out, and the depr~ssion effect.
In particular, it is to be pointed out that the leather pieces are not subject to violent mechanical stresses, but only to a kind of massage produced by said swirling movement, which results in obvious quality advantage.
- 35 An important feature of the subject process derives from the fact that it is carried out in closed tight containers. Thus, the diffusion of miasma into the CA 022~3486 1998-10-30 W 0 97/423S0 PCT~97/00432 environment is avoided, improving the working conditions in the field of the leather tanning treatment.
Moreover, the proposed process considerably reduces the problem of the waste disposal and/or neutralisation and allows to save both energy and substances used particularly for tanning and dyeing.
It must be stressed that the process herein described can be carried out also without leather washing.
Fig. 5a shows another embodiment of the subject apparatus, in which more treatment containers are used for carrying out a process with the same steps o as described for the apparatus of the fig. 4a. There are provided four containers 4a, 4b, 4c, 4d, arranged in a row and used respectively for the steps of soaking, liming, pickling and tanning with simultaneous dyeing and possibly greasing.
The tanks with solutions for carrying out these steps and subsequent IS washings, are indicated with the same numerals as in fig. 4a and are provided with valve means and pumps, not shown, since of the same type as described previously.
In this case, the frames 2, supporting the spread pieces of leather, are mounted, e.g. on a carrier 28, integral with conveying means 29, which introduce and withdraw said carrier 28 into and from the containers 4a, 4b, 4c, 4d.
These conveying means 29 include e.g. a carriage 30, that is moved, by not shown motor means, along a guide element 31 integral with a fixed frame 32 of the apparatus.
Consequently, in each container there is carried out a predetermined step of the leather treatment and a possible washing of said leather.
Advantageously, the leather is washed in corresponding auxiliary containers 114a, 114b (see fig. 6).
More precisely, after being soaked in the container 4a, the leather is withdrawn therefrom and introduced into the auxiliary container 114a, in which it is washed with a liquid solution taken from the tank 30a.
The liming step is carried out in the container 4b and the subsequent washing in the relative auxiliary container 114b.
This way of proceeding, i.e. washing the leather in auxiliary containers, avoids3s cleaning the containers 4a, 4b after the washing operations following soaking CA 022~3486 1998-10-30 W 097t42350 PCT~B97/00432 and liming, respectively.
The apparatus shown in fig. 5b carries out the treatment steps already described with reference to fig. 4b.
In the containers 4a, 4b, 4c, 4d, the leather is soaked, limed, pickled, pre-s tanned, tanned, and lastly, dyed with simultaneous greasing.
The containers, in which these steps are performed, are indicated with the same numerals as in fig. 4b.
Also in this case, washing following the soaking, liming and pre-tanning steps can be carried out in relative auxiliary containers like in the case illustrated in l0 fig. 6.
It is obvious that if the leather treatment requires a number of operations different from the two illustrated exai"ples (figs. 4a, 5a and 4b, Sb), the apparatus will be correspondingly modified, while all the advantages of the invention will be maintained.
S Also in the embodiments shown in Figures 5a,5b,6 the liquid solutions exiting from their respective containers may be sent to a common discharge manifold.
The preferred embodiment of the process features the following technical-functional aspects:
- container 4 (or containers) kept fixed;
- pieces of leather spread and spaced apart;
- treatments carried out in a container, which is closed tight and kept in depression already before the liquid solution has been introduced therein;
- swirling of the liquid solution, that causes a kind of massage of the leather.
According to a variation of the process, the container 4 (or containers 4a, 4b, 4c, 4d) can rotate about their transversal and/or longitudinal axis, so as to create a relative movement between the pieces of leather and the liquid solution used in a treatment step or subsequent washing.
Advantageously, the liquid solution contained in the tanks 111a, 111b reduces 30 dramatically and /or neutralises all the volatile compounds, which are generated inside the container 4 (or containers 4a, 4b, 4c 4d, 4e, 4fl during the leather treatment.
On this purpose, more containers 111 can be provided, arranged parallel one to another, and each of them containing a liquid solution for reducing ~ , . . , . , . .. , . ....... . , . . ~ , .. . ... , ~ .. .
CA 022~3486 1998-10-30 W O 97/42350 PCT~B97/00432 -13-dramatically andlor neutralising at ieast one predetermined volatile compound.
It is possible for the control unit 14 to act on suitable means (e.g. electric valves) connected with these tanks, so as to introduce one or more of them, arranged in a row, into the pipe 110, in relation to the treatment step being s carried out in the container 4 and therefore, to the kind of the volatile compound generated during this step.
In case of more containers, the pipe 110, connecting each of them to suction means 11, is linked with a series of tanks 111 performing the above described functions.
o Each supply tank can be provided with means for mixing the liquid solution contained therein, means which are not shown since they are in the knowledge of those skilled in the art.
Figure 7 shows another embodiment of the apparatus, in which numerals 201, 202, 203, 204 indicate supply tanks conlc.;.,i,,g the liquid solutions for soaking, s liming, pickling and tanning. Numerals 212a, 212b, 212c, 212d indicate corresponding heat exchanger (co"l,~l'ed by the control unit 14 via links S1, SZ, S3, S4). Numerals 216a, 216b, 216c, 216d indicate the corresponding supply pumps also operated by the control unit 14, via connections P1, P2, P3 and P4.
20 In this case, the ejector means, or grating 9 can be set in communication with outside (normal operation condition of the container 4) via a related electric valve 2~0 operated by the control unit.
As an alternative, the ejector means 9 can be connected to one or another of a series of auxiliary supply tanks 300a, 300b, 300c, 300d (for i"stal~ce, four 2s tanks have been provided, however, their number can be bigger or smaller than four), via related electric valves 301a, 301b, 301c, 301d also operated by the control unit.
Each auxiliary supply tank contains a suitable substance, either pure or properly diluted, which is to be used together with the liquid solutions of the 30 supply tanks 212a, 212b, 212c, 212d during a corresponding step of the subjected process.
This configuration determines favourable conditions, in that it allows to mix this substance with the liquid solution each time concerned, in the pre-established percentage and/or weight, so as to affect in the desired way the 3s process steps.
In order to put this possible action into practice, the control unit 14 cuts off the CA 022~3486 1998-10-30 WO 97/42350 PCTnB97100432 connection between the container 4 and the outside environment (by means of the electric valve 250) and sets the container 4 in connection with the predetermined auxiliary supply tank, maintaining this connection for a short time.
s Depression condition inside the container 4 allow in-flowing of the substance coming from the auxiliary supply tank, into the container. The substance flow can be determined by a pump 270, which has not been shown, and can be measured by means of a proper meter, also not shown.
By using a grating 9 for injecting the substances into the container, it is o possible to mix quickly the substances emitted with the liquid solution 5 already present inside the container.
As an alternative, these substances can be supplied to the container either at the same time when the liquid solution 5 is introduced therein, or before liquidsolution introduction.
Moreover, the substances can be supplied to the container also without the help of the grating 9, in accordance with other ways, which will be obvious to those skilled in the art.
When at least one substance (or a dilution of this substance) has been completely let in the container 4, connection between the container and the auxiliary supply tank is cut off and connection between the container and outside environment is restored. In the example shown in Figure 7, the auxiliary supply tanks are associated to the container 4 where process steps are carried out.
Advantageously, the auxiliary supply tanks can be connected to the containers 4a,4b,4c,4d provided by the different configurations of Figures 5a and 6, as well as to containers 4a,4b,4c,4d,4e,4f shown in Figure 5b, and the substances which they contain are used in a way similar to the one just described.
Figure 8 concerns a functional-structural feature of the container 4. In detail,there is shown a duct 600 which sets in communication the bottom region of the container 4 with an intermediate region 601 thereof. More precisely, this intermediate region is situated just under the free surface 602 of the liquid solution 5 inside the container.
A pump is mounted along the duct and operated by the control unit 14, for - 35 withdrawing liquid solution from the container 4, at the region 601, and re-introducing the liquid solution at the bottom. This provokes continuous re-CA 022~3486 1998-10-30 W 097/423S0 PCT~B97/00432 mixing of the liquid substance, thus avoiding, amongst others, settling of solidsubstances.
All what have just been said, brings to the result that the liquid substance is utmost homogeneous in all parts.
s This functional-structural feature can be applied to each container 4a,4b,4c,4d concerned in the embodiments of Figures 5a and 6, as well as to each container 4a,4b,4c,4d,4e,4f included in the embodiments shown in Figure 5b.
With reference to Figures 9a,9b, numeral 500 indicates a vapour recovery unit.
o Advantageously, more recovery units are provided, for instance in number at least equal to the number of steps which form the process carried out inside the container 4.
Figures 9a,9b show only one recovery unit, since the other ones operate exactly in the same way.
15 This recovery unit includes an electric valve 404 mounted along a duct 450 which connects the suction means 11 and container inside. Two pipes 460,479, namely first pipe and second pipe, derive from the duct 450 and have, mounted along them, a three-way electric valve 401 and a two-way electric valve 402, respectively.
20 These pipes cross the tight cover of a condensation vessel 400, under which, at its upper part, there is a baffle 480 arranged inclined. The first pipe 460 open end is positioned below the inclined baffle, while the second pipe 470 open end is positioned above the baffle.
The bottom of the vessel is connected to the bottom of the container 4, via a 25 piping 490 which has an electric valve 403.
All the just mentioned electric valves 401,402,403,404 are operated by the control unit 14.
In the operation condition shown in ~igure 9a, the flow H sucked from the colltainer 4 by the suction means 11 passes through the vessel 400. This flow 30 is sub~tarllially formed by a mix of air (introduced into the container via the ejecting means 9) and vapour formed by the liquid solution 5. This mix expands in the vessel, getting colder, and great part of the vapour condenses.
The liquid thus obtained is collected at the bottom of the vessel and its level gradually increases.
A sensor 405 detects when a certain level has been reached and sends a CA 022~3486 1998-10-30 signal to the control unit 14, that determines the operation condition of Figure9b by operating the above mentioned electric valves.
In this condition, the vessel 400 is by-passed, because the valve 404 is on, while the valve 401 sets the vessel inside in communication with the outside environment and the second pipe 470 is cut off by setting the valve 402 off.
Since the container 4 is under depression, a flow K of liquid passes from the vessel to the container. A proper sensor, that is not shown, detects the level in the vessel being at the minimum and the control unit changes the operating condition of the unit 500 restoring the condition of Figure 9a.
o What have just been said is an extremely advantageous feature, because in this way great part of the evaporated liquid can be recovered and is not brought to the suction means 11.
The baffle 480 forms a partition between the air-vapour mix inlet region (first pipe 460) and the air suction region (second pipe 470), so that the minimum s amount of vapour which is anyway sent to the suction means is negligible.
With a different liquid solution 5 (for process step different from the previousone~, a related recovery unit 500 is further provided with a manifold 410 which sets in communication all the recovery units at one side with the top of the container and at the other side with the bottom of the container, via a related piping 490a. For each container 4a,4b,4c,4d (shown in Figures 5a and 6) and 4a,4b,4c,4d,4e,4f (shown in Figure 5b) one recovery unit 500 like the one just described can be provided.
According to an interesting variation of the proposed process, advantageous results obtained on the leather by combined action of depression and swirling movement can be further increased and improved by subjecting the liquid solution to ultrasounds.
This can be carried out by a suitable sonotrode of known type (not shown) connected to the container and controlled by the control unit 14.
It is understood that what above, has been stated as a pure, non limitative example, therefore possible functional variations of the proposed process steps remain within the protective scope of the invention as claimed hereinafter.
Similar observation are to be considered with reference to means and devices which form the proposed apparatus, in which measure instruments can be used to measure the inlet and outlet flow rate for each container or supply tank which is each time concerned.
.. . . ..
TECHNICAL FIELD
The present invention concerns tannage of leather and the like.
BACKGROUND ART
It is known that animal skin is tanned, so as not to putrefy, with solutions that remain irreversibly fixed thereon, turning it into hide.
This treatment includes different steps, which are often complex and requiring o relatively much time.
When delivered to tannery, generally dried with salts, rawhide is initially subjected to preparation for real tanning.
This preparation includes first a soaking step, i.e. removing impurities that cover both inner flesh side and outer or grain side, as well as preserving solutions, so as to bring the leather back to its natural softness.
The leather to be treated is soaked in drums containing suitable liquid solutions.
These drums are provided inside with immovable paddles or stakes, which act on the leather during drum rotation.
Therefore, the treatment consists of combined chemical action of the liquid solution and the mechanical action performed on the leather and lasts six to twenty four hours.
Afterwards, a fleshing step follows, with which the fat is removed from the soaked leather, and subsequently liming treatment follows for removing hair and reveal the derma.
Liming is performed in suitable drums with alkaline substances, such as sulphides or lime, which make the leather tissue swell and dissolve the hair roots.
More precisely, the leather swells up, the fats turn into calcium salts and proteins forming the leather are modified due to breaking of principal and secondary links of the proteic chains and, sl~hsequently, the hair detaches - from the leather.
The substances used for liming, and at the same time for "opening" the CA 022~3486 1998-10-30 leather pores in order to execute real tanning and dyeing, are highly polluting,which results in all known problems of waste disposal and/or purification.
Liming step requires usually twenty four hours.
Then, thus prepared leather is decalcined and bated, again in suitable drums.
s Due to decalcination step, usually with decalcinating salts, the retained lime is removed.
Bating is a biological action which softens leather grain by enzymes which partly dissolve elastic fibres, causing the leather relaxation.
Subsequently, the leather is subjected to pickling, i.e. treatment, which o guarantees more rapid and complete penetration of the tanning salts.
In fact, bated leather, having basic reaction, cannot be tanned with e.g.
tanning salts of chromium, because it would result in a chemical reaction, which would close the leather pores.
Therefore, the leather is acidified with small quantities of acid, with the presence of salts (usually sodium chloride) so as to prevent swelling. This step is performed in a drum and lasts an average of ten - twelve hours.
The real tanning treatment is carried out inside the aforementioned drums, by means of vegetable solutions, such as natural or synthetic tanning solutions, or by mineral salts, mainly chromium or the like salts.
The liming, bating, pickling and tanning steps altogether require an average of not less than forty eight hours (it can vary according to the type of the leather to be treated).
The tanned leather, suitably pressed to remove a part of absorbed water, selected and skived, is subjected to dyeing treatment, otherwise called re-tanning.
This dyeing step requires an average of eight hours.
Thus, the above mentioned tanning treatments require, as has been alreadysaid, much time, which can take an average of one week.
This results in the necessity for using a relatively big number of huge drums in3n order to achieve an adeqll~te productivity. The pieces of leather to be treated are thrown into the drums in bulk and are subjected directly to a mechanical action, which sometimes can damage them.
- A not minor disadvantage of traditional tanning processes derives from the fact that the working environment is very harmful, due mainly to miasma CA 022~3486 1998-10-30 W O 971423~0 PCT~B97/00432 produced by the aforementioned drums.
Moreover, there is a serious problem of disposal of liquids discharged at the end of the above mentioned treatments, in particular of the substances used for liming.
s SUMMARY OF THE INVENTION
The object of the present invention is to propose a process, that allows tanning treatments of leather and the like to be carried out in less time with respect to the known systems, and that, at the same time, guarantees the 10 high quality of tanned leather as well as high throughput, the whole being obtained with reduced quantity of required energy, with respect to known techniques.
Another principal object of the present invention is to propose a process that can be carried out by an apparatus, which allows to operate in a non-harmful 15 working environment, and which considerably reduces the problems connected with waste disposal.
Yet a further object of the present invention is to propose a process, which allows to reduce markedly a quantity of used substances with the same quality of tanned leather.
20 Still another object of the invention is to propose a process, whose carrying out does not pollute the air.
Moreover, the invention has another object of proposing an apparatus, which carries out the aforementioned method.
The above mentioned objects are obtained by a process of treatment of 2s leather and the like, which includes:
disposing spread pieces of leather to be treated, spaced apart, into a container;
introducing liquid solutions into said container, in sequence and with predetermined intervals, for pe, rvn"i"g various steps of leather tanning 30 treatment, said liquid solutions being discharged from the container, after each step has been completed;
maintaining deprt:ssion inside said container, at least for the duration of eachsingle step;
generating, during each step, a relative movement between the liquid solution CA 022~3486 1998-10-30 and said pieces of leather, so as to intensify the action of said liquid solution on said pieces of leather.
The process is carried out by means of an apparatus which includes:
a container to be closed tight;
5 a plurality of supports, which can be introduced and withdrawn from said container, and on which the corresponding spread pieces of leather are fastened, these supports being situated in said container in such a way as to keep said pieces of leather spaced out;
a hrst series of tanks containing predetermined liquid solutions for lo corresponding leather treatment steps;
on/off and control means which connect each of said tanks to the container so as to introduce therein the relative liquid solution for corresponding leather treatment step;
suction means for maintaining depression inside said container at least while 15 performing the leather treatment steps;
means for generating relative movement between a liquid solution and said pieces of leather so as to intensify the action of said liquid solution thereon.According to a different embodiment, the process includes:
disposing spread pieces of leather to be treated, spaced apart, into a first 20 container;
introducing liquid solution into said container for performing a step of leathertanning treatment;
maintaining depression inside said conta;ner during performing of said step;
generating, during said step, relative movement between the liquid solution 25 and said pieces of leather, so as to strengthen the action of said liquid solution on said pieces of leather;
discharging said liquid solution from said hrst collldi"er;
withdrawing said pieces of leather from the first container;
repeating the above mentioned operations in further containers so as to 30 perform remaining steps of the leather tanning treatment.
According to a different embodiment, the apparaLus includes:
a plurality of containers to be closed tight, inside which predetermined leathertreatment steps are carried out;
, , CA 022~3486 1998-10-30 a plurality of supports, which can be introduced and withdrawn from said ~ containers, and on which the corresponding spread pieces of leather are fastened, these supports being situated in said containers in such a way as to - keep spaced out said pieces of leather;
s a first series of tanks containing predetermined liquid solutions for corresponding leather treatment steps;
on/off and control means, which connect each of said tanks to the re~ative container so as to introduce therein the relative liquid solution for a corresponding leather treatment step;
lo suction means for maintaining depression inside each of said containers at least during performing therein of the relative leather treatment steps;
means for generating, inside each of said containers, relative movement between a corresponding liquid solution and said pieces of leather so as to intensify the action of said li~uid solution thereon.
15 Further characleristics and features are pointed out in the sub-claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The characteristic features of the invention will become pointed out in the following description, with particular reference to the enclosed drawings, in 20 which:
- fig. 1 shows a plan view of supporting means for a piece of leather to be treated;
- figs. 2a, 2b and 2c show schematic views of containers into which the above mentioned support means are ~lisposed, with different a"~nge"lents, 2s respectively;
- fig. 3 shows a schematic vertical section view of said container, during one step of the leather treatment;
- figs. 4a and 4b, show ~iayra"~s of apparatuses for carrying out corresponding tanning treatments accor li.,g to the method, being the subject 30 of the present invention;
- figs. 5a, 5b show diagrams of two different embodiments of the above mentioned apparatus, which carry the method in a different way;
- fig. 6 shows a possible diagram of an apparatus, which carries the method in a further way;
CA 022~3486 1998-10-30 W O 97/42350 PCT~B97/00432 -6-- Fig. 7 shows a further embodiment of the apparatus;
- Fig. 8, shows a constructive variation of the apparatus container;
- Figures 9a and 9b show two schematic diagrams of a facility for vapour recovey in both operation conditions.
s BEST MODES OF CARRYING OUT THE INVENTION
With reference to the above mentioned figures, numeral 1 indicates a piece of leather to be subjected to tanning treatment according to the subject process.
According to this process, the piece of leather to be treated 1 is spread on a l0 respective open support, e.g. frame 2 shown in fig. 1.
The piece of leather 1 is fastened to the frame 2 by a series of expanders 3 of known type.
The frames 2 supporting the spread pieces of leather 1 are introduced into a container 4, kept fixed according to preferred embodiment, which is to be s closed tight, for the treatment with a sl~it~h'E liquid solution introduced therein.
The frames 2 supporting the spread pieces of leather 1 are introduced into the container 4 preferably in vertical arrangement, regularly spaced apart, as seen in figure 2a.
Nevertheless, it is possible to arrange the frames 2 inside the container 4 horizontally (fig. 2b) or inclined (fig. 2c).
In case the pieces of leather are to be arranged vertically, it is sufficient tohang them on a suitable creel, not shown, so as to maintain them mutually spaced apart.
As shown as an example in fig. 3, the upper part of the container 4, which contains the treating liquid solution 5, is closed tight by a cover 6.
In its lower part, the container 4 has holder means 7 for the frames 2 supporting the pieces of leather 1.
Inside the container 4, there is also situated a heat exchanger 8, that heats the liquid solution 5 to the desired temperature. The liquid solution 5 inside the 30 container 4, is swirled during the treatment of the leather pieces 1 spread on the frames 2.
For this purpose, the container 4 features a deliver element 9, situated below the holder means 7 for the frames 2 and formed by a grate provided with a CA 022~3486 1998-10-30 W O 97/423~0 PCTnB97/00432 series of ejectors 10, which eject air in form of bubbles.
Inside the container 4, over the liquid solution 5, depression is maintained by suitable suction means 11 connected with the container by a pipe 110, passing through one of two neutralisation tanks 111a, 111b, which will be s described later. The advantage of keeping the container 4 in depression will be pointed out in the following.
Moreover, due to this depression, a flow of air is sucked from outside via the deliver element 9. Further, the depression reduces the quantity of energy consumed for reaching the desired working temperature. Otherwise, the 0 aforementioned flow of air can be obtained by suitable compression means, connected to the deliver element 9.
In the following, the same reference numbers will indicate means carrying out the same functions.
The apparatus for tanning treatments, shown in fig. 4a, includes a series of 5 tanks 12, preferably tight, containing liquid solutions to be supplied to the container 4 for the aforementioned treatments.
In particular, there are four tanks 12a,12b,12c,12d supplying liquid solutions used correspondingly for the soaking, liming, pickling and tanning steps.
When needed, during the tanning treatment the leather pieces are also dyed.
The tanks are provided with respective heat exchangers 13a, 13b, 13c, 13d which maintain the liquid solutions at desired temperatures. The heat exchangers 13a, 13b, 13c, 13d are controlled by a control unit 14 by connections indicated with S1, S2, S3 and S4.
The supply tanks are connected with respective jet pipes 15a, 15b, 15c and 2s 15d, equipped with related pumps 16a, 16b, 16c and 16d, controlled, in theirturn, by the control unit 14 through connections indicated with P1, P2, P3 and P4.
The jet pipes 15a, 15b, 15c and 15d are connected to an inlet pipe 17 of the container 4 by a valve means 18 which is controlled by the control unit 14.
The bottom of the container 4 features an outlet pipe 19, provided with a pump 20, controlled by the control unit 14.
The outlet pipe 19 is connected alternatively, by a valve means 21, with discharge pipes 22a, 22b, 22c and 22d, communicating with respective waste tanks 23a, 23b,23c and 23d of the liquid solutions used in the container 4.
The waste tanks 23 communicate with corresponding supply tanks 12 by CA 022~3486 1998-10-30 W 097/42350 PCT~B97/00432 means of respective return pipes 24a, 24b, 24c, 24d, equipped with respective pumps 25a, 25b, 25c, 25d, controlled by the control unit 14.
As an alternative constructive form, the discharge pipes 22a, 22b, 22c and 22d lead all to a unique manifold (which has not been shown) which is 5 connected to a suitable cleaner.
In practice, in order to perform each of the aforementioned tanning treatment steps, the container 4 is fed with the liquid solution taken from the relative supply tank 12.
According to a preferred embodiment, the apparatus includes also at least lO other two tanks 30a, 30b, containing washing liquid solutions, which will be described later, and provided with relative jet pipes 31, 31b, featuring relative pumps 32a, 32b controlled by the control unit 14.
These pipes are connected to an inlet duct 33 of the container 4 by a valve means 34 co"l,ollcd by the control unit 14.
S The aforementioned outlet pipe 19, connected to the bottom of the container 4, can be also connected, by the valve means 21, to one or the other of discharge pipes 35a, 35b, flowing into the tanks 30a, 30b, respectively.
Inside the container 4, the liquid solution is swirled by the air flow produced,as has been previously described, in the liquid solution.
20 It is to be pointed out that before each single step is carried out, more precisely, before the container is fed with liquid solution, depression is created therein so as to swell the leather making it spongy and thus facilitating the action of liquid solution thereon.
The above mentioned swirling causes a kind of massage on the leather 2s pieces, that replaces the mechanical action of known systems without damaging the leather.
When each of said treatment steps is completed, the used liquid solution is withdrawn from the container 4 and sent to the relative waste tank 23. After having been regenerated, by means of techniques which are well known by 30 those skilled in the art, this liquid solution can be let again into the corresponding supply tank 12, for a new tanning cycle.
The soaking treatment is carried out with the liquid solution contained in the tank 12a; water, possibly added with chemical promoters.
Due to depression, created before the liquid solution has been introduced, the 3s leather absorbs water more easily, since it tends to swell naturally, thus .. .. .
CA 022~3486 1998-10-30 becoming, as it has already been said, more spongy.
These factors, i.e. combined action of depression and swirling, reduce the time required for the soaking step.
When the soaking has been finished, the leather pieces are washed with 5 water contained in the tank 30a.
The liming treatment is performed with the liquid solution contained in the tank12b, according to oxidising method, e.g. by sodium chlorite or enzyme agents.
It is to be pointed out that sodium chlorite cannot be used in the liming step carried out in wooden drums, because it frees chlorine, which corrodes the l o wood .
Since pulled by the suction means 11 and freed through the pipe 110, chlorine enters one of the tanks 111a, 111b, which contains a solution of sodium hyposulphite, that, as it is known, neutralises chlorine. In this way, the suction means 11 are protected and the problem of disposal of substances used for 15 liming treatment, is resolved.
In the present case, the combined effect of depression, which swells the leather, of sodium chlorite and of massage performed on the leather by the swirled air, allows to carry out the liming treatment.
This is considerably advantageous for the following reasons:
20 - use of a substance, whose disposal (more precisely, neutralisation) is not very troublesome;
- due to depression in working environment, the consume of energy is reduced;
- the pieces of leather are not mechanically stressed.
2s It is also to be pointed out that the leather swelling makes also the pores open, which is advantageous for subsequent tanning and dyeing treatments.
The liming step requires about five hours. After having been limed, the leather is washed with the contents of the tank 30b.
The iiming step is followed by pickling step, which is carried out using the 30 con~ents of the tank 12c; the effect of this operation is intensified by the massage of the leather performed by the swirling.
The liquid solution contained in the tank 12d is used for the real tanning step and, when needed, for the dyeing step, the latter being performed by colouring agents (e.g. vegetable colouring agents) dispersed in the liquid CA 022~3486 1998-10-30 W O 97/42350 PCT~B97/00432 solution.
This liquid solution can also contain agents facilitating leather greasing. The time required for accomplishment of these steps is reduced because the pores remain open due to the depression effect. Also the quantity of tanning and dyeing substances is lower with respect to traditional methods.
In fact, in the described conditions, (i.e. Ieather swollen, thus more spongy), the concentration in the liquid solution of the tanning and dyeing agents, whichare transferred from the liquid solution to the leather (where they remain irreversibly fixed), is reduced with respect to known systems, therefore the o quantity of these agents is smaller, but the quality of the obtained result remains the same. The pickling, tanning and dyeing operations require about 24 - 36 hours.
It is known that the real tanning l,~l",ent can be preceded by the so-called pre-tanning and that dyeing (known also as re-tanning), carried out simultaneously with the agents for leather greasing, can be performed separately from and after the real tanning treatment.
The apparatus that carries out the above mentioned variants, is schematically shown in fig. 4b, where the numeral 12e indicates the tank containing the liquid pre-tanning products, 23e indicates the tank containing the waste liquid after the pre-tanning has been completed, 30d indicates the tank containing the solution for washing the leather after the pre-tanning has been completed, 12f indicates the tank with liquid solution for leather re-tanning and greasing and 23f indicates the tank, which receives waste from the container 4 after the last step has been completed.
Generally, it has been proved that the process, being the subject of the present invention, allows to carry out leather tanning in considerably reduced amount of time, with respect to the traditional techniques, guaranteeing at the same time a high quality of the tanned leather.
This result is helped also by spreading of leather on the frames 2, swirling 30 movement due to the air flow produced in the liquid solution 5, with which the - treatment is being carried out, and the depr~ssion effect.
In particular, it is to be pointed out that the leather pieces are not subject to violent mechanical stresses, but only to a kind of massage produced by said swirling movement, which results in obvious quality advantage.
- 35 An important feature of the subject process derives from the fact that it is carried out in closed tight containers. Thus, the diffusion of miasma into the CA 022~3486 1998-10-30 W 0 97/423S0 PCT~97/00432 environment is avoided, improving the working conditions in the field of the leather tanning treatment.
Moreover, the proposed process considerably reduces the problem of the waste disposal and/or neutralisation and allows to save both energy and substances used particularly for tanning and dyeing.
It must be stressed that the process herein described can be carried out also without leather washing.
Fig. 5a shows another embodiment of the subject apparatus, in which more treatment containers are used for carrying out a process with the same steps o as described for the apparatus of the fig. 4a. There are provided four containers 4a, 4b, 4c, 4d, arranged in a row and used respectively for the steps of soaking, liming, pickling and tanning with simultaneous dyeing and possibly greasing.
The tanks with solutions for carrying out these steps and subsequent IS washings, are indicated with the same numerals as in fig. 4a and are provided with valve means and pumps, not shown, since of the same type as described previously.
In this case, the frames 2, supporting the spread pieces of leather, are mounted, e.g. on a carrier 28, integral with conveying means 29, which introduce and withdraw said carrier 28 into and from the containers 4a, 4b, 4c, 4d.
These conveying means 29 include e.g. a carriage 30, that is moved, by not shown motor means, along a guide element 31 integral with a fixed frame 32 of the apparatus.
Consequently, in each container there is carried out a predetermined step of the leather treatment and a possible washing of said leather.
Advantageously, the leather is washed in corresponding auxiliary containers 114a, 114b (see fig. 6).
More precisely, after being soaked in the container 4a, the leather is withdrawn therefrom and introduced into the auxiliary container 114a, in which it is washed with a liquid solution taken from the tank 30a.
The liming step is carried out in the container 4b and the subsequent washing in the relative auxiliary container 114b.
This way of proceeding, i.e. washing the leather in auxiliary containers, avoids3s cleaning the containers 4a, 4b after the washing operations following soaking CA 022~3486 1998-10-30 W 097t42350 PCT~B97/00432 and liming, respectively.
The apparatus shown in fig. 5b carries out the treatment steps already described with reference to fig. 4b.
In the containers 4a, 4b, 4c, 4d, the leather is soaked, limed, pickled, pre-s tanned, tanned, and lastly, dyed with simultaneous greasing.
The containers, in which these steps are performed, are indicated with the same numerals as in fig. 4b.
Also in this case, washing following the soaking, liming and pre-tanning steps can be carried out in relative auxiliary containers like in the case illustrated in l0 fig. 6.
It is obvious that if the leather treatment requires a number of operations different from the two illustrated exai"ples (figs. 4a, 5a and 4b, Sb), the apparatus will be correspondingly modified, while all the advantages of the invention will be maintained.
S Also in the embodiments shown in Figures 5a,5b,6 the liquid solutions exiting from their respective containers may be sent to a common discharge manifold.
The preferred embodiment of the process features the following technical-functional aspects:
- container 4 (or containers) kept fixed;
- pieces of leather spread and spaced apart;
- treatments carried out in a container, which is closed tight and kept in depression already before the liquid solution has been introduced therein;
- swirling of the liquid solution, that causes a kind of massage of the leather.
According to a variation of the process, the container 4 (or containers 4a, 4b, 4c, 4d) can rotate about their transversal and/or longitudinal axis, so as to create a relative movement between the pieces of leather and the liquid solution used in a treatment step or subsequent washing.
Advantageously, the liquid solution contained in the tanks 111a, 111b reduces 30 dramatically and /or neutralises all the volatile compounds, which are generated inside the container 4 (or containers 4a, 4b, 4c 4d, 4e, 4fl during the leather treatment.
On this purpose, more containers 111 can be provided, arranged parallel one to another, and each of them containing a liquid solution for reducing ~ , . . , . , . .. , . ....... . , . . ~ , .. . ... , ~ .. .
CA 022~3486 1998-10-30 W O 97/42350 PCT~B97/00432 -13-dramatically andlor neutralising at ieast one predetermined volatile compound.
It is possible for the control unit 14 to act on suitable means (e.g. electric valves) connected with these tanks, so as to introduce one or more of them, arranged in a row, into the pipe 110, in relation to the treatment step being s carried out in the container 4 and therefore, to the kind of the volatile compound generated during this step.
In case of more containers, the pipe 110, connecting each of them to suction means 11, is linked with a series of tanks 111 performing the above described functions.
o Each supply tank can be provided with means for mixing the liquid solution contained therein, means which are not shown since they are in the knowledge of those skilled in the art.
Figure 7 shows another embodiment of the apparatus, in which numerals 201, 202, 203, 204 indicate supply tanks conlc.;.,i,,g the liquid solutions for soaking, s liming, pickling and tanning. Numerals 212a, 212b, 212c, 212d indicate corresponding heat exchanger (co"l,~l'ed by the control unit 14 via links S1, SZ, S3, S4). Numerals 216a, 216b, 216c, 216d indicate the corresponding supply pumps also operated by the control unit 14, via connections P1, P2, P3 and P4.
20 In this case, the ejector means, or grating 9 can be set in communication with outside (normal operation condition of the container 4) via a related electric valve 2~0 operated by the control unit.
As an alternative, the ejector means 9 can be connected to one or another of a series of auxiliary supply tanks 300a, 300b, 300c, 300d (for i"stal~ce, four 2s tanks have been provided, however, their number can be bigger or smaller than four), via related electric valves 301a, 301b, 301c, 301d also operated by the control unit.
Each auxiliary supply tank contains a suitable substance, either pure or properly diluted, which is to be used together with the liquid solutions of the 30 supply tanks 212a, 212b, 212c, 212d during a corresponding step of the subjected process.
This configuration determines favourable conditions, in that it allows to mix this substance with the liquid solution each time concerned, in the pre-established percentage and/or weight, so as to affect in the desired way the 3s process steps.
In order to put this possible action into practice, the control unit 14 cuts off the CA 022~3486 1998-10-30 WO 97/42350 PCTnB97100432 connection between the container 4 and the outside environment (by means of the electric valve 250) and sets the container 4 in connection with the predetermined auxiliary supply tank, maintaining this connection for a short time.
s Depression condition inside the container 4 allow in-flowing of the substance coming from the auxiliary supply tank, into the container. The substance flow can be determined by a pump 270, which has not been shown, and can be measured by means of a proper meter, also not shown.
By using a grating 9 for injecting the substances into the container, it is o possible to mix quickly the substances emitted with the liquid solution 5 already present inside the container.
As an alternative, these substances can be supplied to the container either at the same time when the liquid solution 5 is introduced therein, or before liquidsolution introduction.
Moreover, the substances can be supplied to the container also without the help of the grating 9, in accordance with other ways, which will be obvious to those skilled in the art.
When at least one substance (or a dilution of this substance) has been completely let in the container 4, connection between the container and the auxiliary supply tank is cut off and connection between the container and outside environment is restored. In the example shown in Figure 7, the auxiliary supply tanks are associated to the container 4 where process steps are carried out.
Advantageously, the auxiliary supply tanks can be connected to the containers 4a,4b,4c,4d provided by the different configurations of Figures 5a and 6, as well as to containers 4a,4b,4c,4d,4e,4f shown in Figure 5b, and the substances which they contain are used in a way similar to the one just described.
Figure 8 concerns a functional-structural feature of the container 4. In detail,there is shown a duct 600 which sets in communication the bottom region of the container 4 with an intermediate region 601 thereof. More precisely, this intermediate region is situated just under the free surface 602 of the liquid solution 5 inside the container.
A pump is mounted along the duct and operated by the control unit 14, for - 35 withdrawing liquid solution from the container 4, at the region 601, and re-introducing the liquid solution at the bottom. This provokes continuous re-CA 022~3486 1998-10-30 W 097/423S0 PCT~B97/00432 mixing of the liquid substance, thus avoiding, amongst others, settling of solidsubstances.
All what have just been said, brings to the result that the liquid substance is utmost homogeneous in all parts.
s This functional-structural feature can be applied to each container 4a,4b,4c,4d concerned in the embodiments of Figures 5a and 6, as well as to each container 4a,4b,4c,4d,4e,4f included in the embodiments shown in Figure 5b.
With reference to Figures 9a,9b, numeral 500 indicates a vapour recovery unit.
o Advantageously, more recovery units are provided, for instance in number at least equal to the number of steps which form the process carried out inside the container 4.
Figures 9a,9b show only one recovery unit, since the other ones operate exactly in the same way.
15 This recovery unit includes an electric valve 404 mounted along a duct 450 which connects the suction means 11 and container inside. Two pipes 460,479, namely first pipe and second pipe, derive from the duct 450 and have, mounted along them, a three-way electric valve 401 and a two-way electric valve 402, respectively.
20 These pipes cross the tight cover of a condensation vessel 400, under which, at its upper part, there is a baffle 480 arranged inclined. The first pipe 460 open end is positioned below the inclined baffle, while the second pipe 470 open end is positioned above the baffle.
The bottom of the vessel is connected to the bottom of the container 4, via a 25 piping 490 which has an electric valve 403.
All the just mentioned electric valves 401,402,403,404 are operated by the control unit 14.
In the operation condition shown in ~igure 9a, the flow H sucked from the colltainer 4 by the suction means 11 passes through the vessel 400. This flow 30 is sub~tarllially formed by a mix of air (introduced into the container via the ejecting means 9) and vapour formed by the liquid solution 5. This mix expands in the vessel, getting colder, and great part of the vapour condenses.
The liquid thus obtained is collected at the bottom of the vessel and its level gradually increases.
A sensor 405 detects when a certain level has been reached and sends a CA 022~3486 1998-10-30 signal to the control unit 14, that determines the operation condition of Figure9b by operating the above mentioned electric valves.
In this condition, the vessel 400 is by-passed, because the valve 404 is on, while the valve 401 sets the vessel inside in communication with the outside environment and the second pipe 470 is cut off by setting the valve 402 off.
Since the container 4 is under depression, a flow K of liquid passes from the vessel to the container. A proper sensor, that is not shown, detects the level in the vessel being at the minimum and the control unit changes the operating condition of the unit 500 restoring the condition of Figure 9a.
o What have just been said is an extremely advantageous feature, because in this way great part of the evaporated liquid can be recovered and is not brought to the suction means 11.
The baffle 480 forms a partition between the air-vapour mix inlet region (first pipe 460) and the air suction region (second pipe 470), so that the minimum s amount of vapour which is anyway sent to the suction means is negligible.
With a different liquid solution 5 (for process step different from the previousone~, a related recovery unit 500 is further provided with a manifold 410 which sets in communication all the recovery units at one side with the top of the container and at the other side with the bottom of the container, via a related piping 490a. For each container 4a,4b,4c,4d (shown in Figures 5a and 6) and 4a,4b,4c,4d,4e,4f (shown in Figure 5b) one recovery unit 500 like the one just described can be provided.
According to an interesting variation of the proposed process, advantageous results obtained on the leather by combined action of depression and swirling movement can be further increased and improved by subjecting the liquid solution to ultrasounds.
This can be carried out by a suitable sonotrode of known type (not shown) connected to the container and controlled by the control unit 14.
It is understood that what above, has been stated as a pure, non limitative example, therefore possible functional variations of the proposed process steps remain within the protective scope of the invention as claimed hereinafter.
Similar observation are to be considered with reference to means and devices which form the proposed apparatus, in which measure instruments can be used to measure the inlet and outlet flow rate for each container or supply tank which is each time concerned.
.. . . ..
Claims (52)
1. Process of treatment of leather and the like, characterised in that it includes:
disposing spread pieces of leather to be treated (1), spaced apart, into a container (4);
introducing liquid solutions into said container (4), in sequence and with predetermined intervals, for performing various steps of leather tanning treatment, said liquid solutions being discharged from the container, after each step has been completed;
maintaining depression inside said container, at least for the duration of each single step;
generating, during each step, a relative movement between the liquid solution and said pieces of leather, so as to intensify the action of said liquid solution on said pieces of leather.
disposing spread pieces of leather to be treated (1), spaced apart, into a container (4);
introducing liquid solutions into said container (4), in sequence and with predetermined intervals, for performing various steps of leather tanning treatment, said liquid solutions being discharged from the container, after each step has been completed;
maintaining depression inside said container, at least for the duration of each single step;
generating, during each step, a relative movement between the liquid solution and said pieces of leather, so as to intensify the action of said liquid solution on said pieces of leather.
2. Process of treatment of leather and the like; characterised in that it includes:
disposing spread pieces of leather to be treated (1), spaced apart, into a firstcontainer (4a);
introducing liquid solution into said container (4a) for performing a step of leather tanning treatment;
maintaining depression inside said container during performing of said step;
generating, during said step, relative movement between the liquid solution and said pieces of leather, so as to strengthen the action of said liquid solution on said pieces of leather;
discharging said liquid solution from said first container;
withdrawing said pieces of leather from the first container;
repeating the above mentioned operations in further containers so as to perform remaining steps of the leather tanning treatment.
disposing spread pieces of leather to be treated (1), spaced apart, into a firstcontainer (4a);
introducing liquid solution into said container (4a) for performing a step of leather tanning treatment;
maintaining depression inside said container during performing of said step;
generating, during said step, relative movement between the liquid solution and said pieces of leather, so as to strengthen the action of said liquid solution on said pieces of leather;
discharging said liquid solution from said first container;
withdrawing said pieces of leather from the first container;
repeating the above mentioned operations in further containers so as to perform remaining steps of the leather tanning treatment.
3. Process, according to claim 1, characterised in that the depression inside the container is created before the liquid solution for a corresponding leather treatment step, is introduced therein.
4. Process, according to claim 2, characterised in that the depression inside each of said containers, in which a leather treatment step is carried out, is created before the corresponding liquid solution is introduced therein.
5. Process, according to claim 1 or 3, characterised in that it includes:
introduction of a first liquid solution for soaking said leather into said container (4), swirling of said liquid solution during said soaking step;
discharging of said solution from the container;
introduction of a second liquid solution for liming said leather into said container (4);
swirling of said liquid solution during said liming step;
discharging of said solution from the container;
introduction of a third liquid solution for pickling said leather into said container (4);
swirling of said liquid solution during said pickling step;
discharging of said solution from the container;
introduction of a fourth liquid solution for simultaneous tanning and dyeing said leather into said container (4);
swirling of said liquid solution during said tanning and dyeing step;
discharging of said solution from the container;
finally, withdrawing the spread pieces of leather from the container.
introduction of a first liquid solution for soaking said leather into said container (4), swirling of said liquid solution during said soaking step;
discharging of said solution from the container;
introduction of a second liquid solution for liming said leather into said container (4);
swirling of said liquid solution during said liming step;
discharging of said solution from the container;
introduction of a third liquid solution for pickling said leather into said container (4);
swirling of said liquid solution during said pickling step;
discharging of said solution from the container;
introduction of a fourth liquid solution for simultaneous tanning and dyeing said leather into said container (4);
swirling of said liquid solution during said tanning and dyeing step;
discharging of said solution from the container;
finally, withdrawing the spread pieces of leather from the container.
6. Process, according to claim 5, characterised in that, in time relation with introduction of at least one liquid solution into said first container between said first, second, third and fourth liquid solutions, also a substance is introducedeither pure or diluted, aimed at co-operating with the related liquid solution in order to carry out a corresponding step of the same process.
7. Process, according to claim 2 or 4, characterised in that it includes:
introduction of a first liquid solution for soaking said leather into said firstcontainer (4a);
swirling said liquid solution during said soaking step;
discharging said solution from the first container;
withdrawing the pieces of leather from the first container (4a);
introduction of said spread pieces of leather, spaced apart, into a second container (4b), which is to be closed tight;
introduction of a second liquid solution for liming said leather into said second container (4b);
maintaining depression in said second container during the liming step;
swirling of said liquid solution during said liming step;
discharging of said solution from the second container;
withdrawing the pieces of leather from the second container (4b);
introduction of said spread pieces of leather, spaced apart, into a third container (4c), which is to be closed tight;
introduction of a third liquid solution for pickling said leather into said third container (4c);
maintaining depression in said third container during the pickling step;
swirling of said liquid solution during said pickling step;
discharging of said solution from the third container;
withdrawing the pieces of leather from the third container (4c);
introduction of said spread pieces of leather, spaced apart, into a fourth container (4d), which is to be closed tight;
introduction of a fourth liquid solution, for performing simultaneously at leasttanning and dyeing of said leather, into said fourth container (4d);
maintaining depression in said fourth container during the tanning and dyeing steps;
swirling of said liquid solution during said tanning and dyeing step;
discharging said fourth solution from the fourth container;
withdrawing the pieces of leather therefrom.
introduction of a first liquid solution for soaking said leather into said firstcontainer (4a);
swirling said liquid solution during said soaking step;
discharging said solution from the first container;
withdrawing the pieces of leather from the first container (4a);
introduction of said spread pieces of leather, spaced apart, into a second container (4b), which is to be closed tight;
introduction of a second liquid solution for liming said leather into said second container (4b);
maintaining depression in said second container during the liming step;
swirling of said liquid solution during said liming step;
discharging of said solution from the second container;
withdrawing the pieces of leather from the second container (4b);
introduction of said spread pieces of leather, spaced apart, into a third container (4c), which is to be closed tight;
introduction of a third liquid solution for pickling said leather into said third container (4c);
maintaining depression in said third container during the pickling step;
swirling of said liquid solution during said pickling step;
discharging of said solution from the third container;
withdrawing the pieces of leather from the third container (4c);
introduction of said spread pieces of leather, spaced apart, into a fourth container (4d), which is to be closed tight;
introduction of a fourth liquid solution, for performing simultaneously at leasttanning and dyeing of said leather, into said fourth container (4d);
maintaining depression in said fourth container during the tanning and dyeing steps;
swirling of said liquid solution during said tanning and dyeing step;
discharging said fourth solution from the fourth container;
withdrawing the pieces of leather therefrom.
8. Process, according to claim 7, characterised in that, in time relation with introduction of said related liquid solution into at least one of said containerfirst, second, third and fourth, at least one substance is introduced either pure or diluted, aimed at co-operating with the related liquid solution in order to carry out a corresponding step of the same process.
9. Process, according to claim 1 or 3, characterised in that it includes:
introduction of a first liquid solution for soaking said leather into said container (4);
swirling of said liquid solution during said soaking step;
discharging said solution from the container;
introduction of a second liquid solution for liming said leather into said container;
swirling of said liquid solution during said liming step;
discharging of said solution from the container;
introduction of a third liquid solution for pickling said leather into said container (4);
swirling of said liquid solution during said pickling step;
discharging of said solution from the container;
introduction of a fourth liquid solution for pre-tanning said leather into said container (4);
swirling of said liquid solution during said pre-tanning step;
discharging of said solution from the container;
introduction of a fifth liquid solution for tanning said leather into said container (4);
swirling of said liquid solution during said tanning step;
discharging of said solution from the container;
introduction of a sixth liquid solution for at least dyeing said leather into said container (4);
swirling of said sixth liquid solution during said dyeing step;
discharging of said solution from the container;
finally, withdrawing the spread pieces of leather from the container.
introduction of a first liquid solution for soaking said leather into said container (4);
swirling of said liquid solution during said soaking step;
discharging said solution from the container;
introduction of a second liquid solution for liming said leather into said container;
swirling of said liquid solution during said liming step;
discharging of said solution from the container;
introduction of a third liquid solution for pickling said leather into said container (4);
swirling of said liquid solution during said pickling step;
discharging of said solution from the container;
introduction of a fourth liquid solution for pre-tanning said leather into said container (4);
swirling of said liquid solution during said pre-tanning step;
discharging of said solution from the container;
introduction of a fifth liquid solution for tanning said leather into said container (4);
swirling of said liquid solution during said tanning step;
discharging of said solution from the container;
introduction of a sixth liquid solution for at least dyeing said leather into said container (4);
swirling of said sixth liquid solution during said dyeing step;
discharging of said solution from the container;
finally, withdrawing the spread pieces of leather from the container.
10. Process, according to claim 9, characterised in that, in time relation with introduction of at least one liquid solution into said first container between said first, second, third, fourth, fifth and sixth liquid solutions, at least one substance is introduced either pure or diluted, aimed at co-operating with the related liquid solution in order to carry out at least one corresponding step ofthe same process.
11. Process, according to claim 2 or 4, characterised in that it includes:
introduction of a first liquid solution for soaking said leather into said firstcontainer (4a);
swirling of said liquid solution during said soaking step;
discharging of said solution from the first container;
withdrawing the pieces of leather from the first container (4a);
introduction of said spread pieces of leather, spaced apart, into a second container (4b), which is to be closed tight;
introduction of a second liquid solution for liming said leather into said second container (4b);
maintaining depression in said second container during the liming step;
swirling of said second liquid solution during said liming step;
discharging of said second liquid solution from the second container;
withdrawing the pieces of leather from the second container (4b);
introduction of said spread pieces of leather, spaced apart, into a third container (4c), which is to be closed tight;
introduction of a third liquid solution for pickling said leather into said third container (4c);
maintaining depression in said third container during the pickling step;
swirling of said third liquid solution during said pickling step;
discharging said solution from the third container;
withdrawing the pieces of leather from the third container (4c);
introduction of said spread pieces of leather, spaced apart, into a fourth container (4d), which is to be closed tight;
introduction of a fourth liquid solution into said fourth container (4d) for pre-tanning of said leather;
maintaining depression in said fourth container during the pre-tanning step;
swirling of said fourth liquid solution during said pre-tanning step;
discharging said fourth solution from the fourth container;
withdrawing the pieces of leather from the fourth container (4d);
introduction of said spread pieces of leather, spaced apart, into a fifth container (4e), which is to be closed tight;
introduction of a fifth liquid solution into said fifth container (4e) for tanning of said leather;
maintaining depression in said fifth container during the tanning step;
swirling of said fifth liquid solution during said tanning step;
discharging of said fifth solution from the fifth container;
withdrawing the pieces of leather from the fifth container (4e);
introduction of said spread pieces of leather, spaced apart, into a sixth container (4f), which is to be closed tight;
introduction of a sixth liquid solution into said sixth container (4e) for dyeing said leather;
maintaining depression in said sixth container during the dyeing step;
swirling of said sixth liquid solution during said dyeing step;
discharging said sixth solution from the sixth container;
withdrawing the pieces of leather therefrom.
introduction of a first liquid solution for soaking said leather into said firstcontainer (4a);
swirling of said liquid solution during said soaking step;
discharging of said solution from the first container;
withdrawing the pieces of leather from the first container (4a);
introduction of said spread pieces of leather, spaced apart, into a second container (4b), which is to be closed tight;
introduction of a second liquid solution for liming said leather into said second container (4b);
maintaining depression in said second container during the liming step;
swirling of said second liquid solution during said liming step;
discharging of said second liquid solution from the second container;
withdrawing the pieces of leather from the second container (4b);
introduction of said spread pieces of leather, spaced apart, into a third container (4c), which is to be closed tight;
introduction of a third liquid solution for pickling said leather into said third container (4c);
maintaining depression in said third container during the pickling step;
swirling of said third liquid solution during said pickling step;
discharging said solution from the third container;
withdrawing the pieces of leather from the third container (4c);
introduction of said spread pieces of leather, spaced apart, into a fourth container (4d), which is to be closed tight;
introduction of a fourth liquid solution into said fourth container (4d) for pre-tanning of said leather;
maintaining depression in said fourth container during the pre-tanning step;
swirling of said fourth liquid solution during said pre-tanning step;
discharging said fourth solution from the fourth container;
withdrawing the pieces of leather from the fourth container (4d);
introduction of said spread pieces of leather, spaced apart, into a fifth container (4e), which is to be closed tight;
introduction of a fifth liquid solution into said fifth container (4e) for tanning of said leather;
maintaining depression in said fifth container during the tanning step;
swirling of said fifth liquid solution during said tanning step;
discharging of said fifth solution from the fifth container;
withdrawing the pieces of leather from the fifth container (4e);
introduction of said spread pieces of leather, spaced apart, into a sixth container (4f), which is to be closed tight;
introduction of a sixth liquid solution into said sixth container (4e) for dyeing said leather;
maintaining depression in said sixth container during the dyeing step;
swirling of said sixth liquid solution during said dyeing step;
discharging said sixth solution from the sixth container;
withdrawing the pieces of leather therefrom.
12. Process, according to claim 11, characterised in that, in time relation withintroduction of said related liquid solution into at least one of said containerfirst, second, third, fourth, fifth and sixth at least one substance is introduced either pure or diluted, aimed at co-operating with the related liquid solution in order to carry out a corresponding step of the same process.
13. Process, according to claim 5 or 9, characterised in that between the end of the liming step and before the pickling treatment, there is an intermediate leather washing step.
14. Process, according to claim 5 or 9, characterised in that between the end of the soaking step and before the liming step, there is an intermediate leatherwashing step.
15. Process, according to claim 9, characterised in that after the pre-tanning step and before the tanning step, there is an intermediate leather washing step.
16. Process, according to claim 7 or 11, characterised in that after the soakingstep there is an intermediate leather washing step carried out in said first container (4a).
17. Process, according to claim 7 or 11, characterised in that after the liming step there is an intermediate leather washing step carried out in said second container (4b).
18. Process, according to claim 7, characterised in that after the pre-tanning step the leather is washed.
19. Process, according to claim 1 or 2, characterised in that the relative movement between the liquid solution and said pieces of leather is obtained by maintaining the container unmoved and ejecting a flow of air into said liquidsolution.
20. Process, according to claim 1 or 2, characterised in that the relative movement between the liquid solution and said pieces of leather is obtained by maintaining the container unmoved and connecting the lower part thereof with outside, thus generating a flow of air, which passes through said liquid solution.
21. Process, according to claim 1 or 2, characterised in that the relative movement between the liquid solution and said pieces of leather is obtained by continuous withdrawing of said liquid solution at a level close to its upper surface 602, from said container 4 and by re-introduction thereof at the bottom of said container.
22. Process, according to any of the previous claims, characterised in that said pieces of leather are spread on respective open support means.
23. Process, according to claim 22, characterised in that said pieces of leatherare arranged vertically.
24. Process, according to claim 22, characterised in that said pieces of leatherare disposed horizontally.
25. Process, according to claim 22, characterised in that said pieces of leatherare inclined with respect to a vertical plane.
26. Process, according to claim 7 or 11, characterised in that after the soakingstep has been completed, the pieces of leather withdrawn from the container, in which this soaking step has been performed, are introduced into an auxiliary container 114a for being washed.
27. Process, according to claim 7 or 11, characterised in that after the liming step has been completed, the pieces of leather withdrawn from the container, in which this liming step has been performed, are introduced into an auxiliary container 114b for being washed.
28. Process, according to claim 11, characterized in that after the pre-tanning step has been completed, the pieces of leather withdrawn from the container, in which this pre-tanning step has been performed, are introduced into an auxiliary container for being washed.
29. Process, according to claim 1 or 3 or 5 or 9, characterised in that, during each of the treatment steps, the related liquid solution for performing each time that step is treated with ultrasounds.
30. Process, according to claim 2 or 4 or 7 or 11, characterised in that, duringeach of the treatment steps, the related liquid solution for performing each time that step is treated with ultrasounds.
31. Apparatus for carrying out treatment of leather and the like, characterised in that it includes:
a container (4) to be closed tight;
a plurality of supports (2), which can be introduced and withdrawn from said container, and on which the corresponding spread pieces of leather (1) are fastened, these supports (2) being situated in said container in such a way as to keep said pieces of leather spaced out;
a first series of tanks (12) containing predetermined liquid solutions for corresponding leather treatment steps;
on/off and control means (14,16,18), which connect each of said tanks to the container so as to introduce therein the relative liquid solution for corresponding leather treatment step;
suction means (11) for maintaining depression inside said container at least while performing the leather treatment steps;
means for generating relative movement between a liquid solution and said pieces of leather so as to intensify the action of said liquid solution thereon.
a container (4) to be closed tight;
a plurality of supports (2), which can be introduced and withdrawn from said container, and on which the corresponding spread pieces of leather (1) are fastened, these supports (2) being situated in said container in such a way as to keep said pieces of leather spaced out;
a first series of tanks (12) containing predetermined liquid solutions for corresponding leather treatment steps;
on/off and control means (14,16,18), which connect each of said tanks to the container so as to introduce therein the relative liquid solution for corresponding leather treatment step;
suction means (11) for maintaining depression inside said container at least while performing the leather treatment steps;
means for generating relative movement between a liquid solution and said pieces of leather so as to intensify the action of said liquid solution thereon.
32. Apparatus, according to claim 31, characterised in that it includes a second series of tanks (23) connected to the container by on/off and control means (14,21,25) so as to receive a liquid solution discharged from said container after a corresponding step has been completed.
33. Apparatus, according to claim 31, characterised in that it includes a seriesof auxiliary tanks (300a,300b,300c,300d) connected to the container by on/off and control means, for introducing a substance, either pure or diluted, into said container, said substance working in combination with a corresponding liquid substance for carrying out at least one leather treatment process step.
34. Apparatus for carrying out treatment of leather and the like, characterised in that it includes:
a plurality of containers (4a,4b,4c,4d) to be closed tight, inside which predetermined leather treatment steps are carried out;
a plurality of supports (2), which can be introduced and withdrawn from said containers, and on which the corresponding spread pieces of leather (1) are fastened, these supports (2) being situated in said containers in such a way as to keep spaced out said pieces of leather;
a first series of tanks (12) containing predetermined liquid solutions for corresponding leather treatment steps;
on/off and control means, which connect each of said tanks to the relative container so as to introduce therein the relative liquid solution for a corresponding leather treatment step;
suction means (11) for maintaining depression inside each of said containers at least during performing therein of the relative leather treatment steps;
means for generating, inside each of said containers, relative movement between a corresponding liquid solution and said pieces of leather so as to intensify the action of said liquid solution thereon.
a plurality of containers (4a,4b,4c,4d) to be closed tight, inside which predetermined leather treatment steps are carried out;
a plurality of supports (2), which can be introduced and withdrawn from said containers, and on which the corresponding spread pieces of leather (1) are fastened, these supports (2) being situated in said containers in such a way as to keep spaced out said pieces of leather;
a first series of tanks (12) containing predetermined liquid solutions for corresponding leather treatment steps;
on/off and control means, which connect each of said tanks to the relative container so as to introduce therein the relative liquid solution for a corresponding leather treatment step;
suction means (11) for maintaining depression inside each of said containers at least during performing therein of the relative leather treatment steps;
means for generating, inside each of said containers, relative movement between a corresponding liquid solution and said pieces of leather so as to intensify the action of said liquid solution thereon.
35. Apparatus, according to claim 26, characterised in that a second series of tanks connected to a corresponding container by on/off and control means, so as to receive a liquid solution discharged from said container after a corresponding step has been completed.
36. Apparatus, according to claim 34, characterised in that for each container (4a,4b,4c,4d) it includes a related auxiliary supply tank (300a,300b,300c,300d) connected to the corresponding container by on/off and control means, for introducing at least one substance, either pure or diluted, into said related container, for carrying out a corresponding leather treatment process step together with the liquid solution introduced into the container.
37. Apparatus, according to claim 31, characterised in that said container (4) is kept unmoved and in that the means generating a relative movement between the liquid solution and the pieces of leather include ejectors (10), which send a jet of air through the liquid solution held in the container.
38. Apparatus, according to claim 34, characterised in that each of said containers is kept unmoved and in that the means generating a relative movement between the liquid solution and the pieces of leather in each container include ejectors (10), which send a jet of air through the liquid solution.
39. Apparatus, according to claim 31, characterised in that at least one tank (111a,111b) for dramatic reduction and/or neutralisation of volatile compounds produced during the leather treatment, is situated along the pipe (110) connecting said suction means (11) with the container (4).
40. Apparatus, according to claim 34, characterised in that at least one tank (111a,111b) for dramatic reduction and/or neutralisation of volatile compounds produced during the leather treatment, is situated along the pipe (110) connecting said suction means (11) with said containers.
41. Apparatus, according to claim 31, characterised in that it includes further tanks (30), which are connected to said container by on/off and control means so as to introduce into and, subsequently discharge suitable liquid solutions from the container for washing the leather after a corresponding step has been completed.
42. Apparatus, according to claim 34, characterised in that it includes further tanks (30), each of which can be connected to a corresponding container by on/off and control means so as to introduce into and, subsequently discharge suitable liquid solutions from said container for washing the leather after a corresponding step has been completed.
43. Apparatus, according to claim 34, characterised in that it includes auxiliary containers (114), each of which can be connected, by on/off and control means, to a corresponding tank containing a predetermined liquid solution introduced into and, subsequently discharged from said auxiliary container, for washing the pieces of leather introduced therein after a treatment step has been completed in a correspondent container.
44. Apparatus, according to claim 31, characterised in that it includes a duct (600) which sets in communication a bottom region of said container (4) with an intermediate region (601) of the same container, located just below a free surface (602) of the liquid solution (5) inside the container, said duct having pump means (603) for continuously transferring said liquid solution from said intermediate region (601) to said bottom region of said container.
45. Apparatus, according to claim 34, characterised in that for each container (4a,4b,4c,4d) it includes a duct (600) which sets in communication a bottom region of said container (4) with an intermediate region (601) of the same container, located just below a free surface (602) of the liquid solution (5) inside the container, said duct having pump means (603) for continuously transferring said liquid solution from said intermediate region (601) to said bottom region of said container.
46. Apparatus, according to claim 31 or 34, characterised in that for each container (4,4a,4b,4c,4d) it includes at least one vapour recovery unit (500) comprising:
a tight closed condensing vessel (400);
first on/off means (401,404,402) operated by a control unit (14) for connecting said vessel in series with a duct (450) which sets in communication said container and said suction means (11);
sensor means (405) for detecting the liquid level inside said vessel, these sensor means co-operate with said control unit (14) to operate said first on/offmeans and second on/off means (403) so as to exclude said vessel from the path of said duct (450), to set in communication the inside of the vessel with the outside environment, and to set in communication the vessel with the container, so that a flow of condensed liquid can be transferred from the vessel to the container.
a tight closed condensing vessel (400);
first on/off means (401,404,402) operated by a control unit (14) for connecting said vessel in series with a duct (450) which sets in communication said container and said suction means (11);
sensor means (405) for detecting the liquid level inside said vessel, these sensor means co-operate with said control unit (14) to operate said first on/offmeans and second on/off means (403) so as to exclude said vessel from the path of said duct (450), to set in communication the inside of the vessel with the outside environment, and to set in communication the vessel with the container, so that a flow of condensed liquid can be transferred from the vessel to the container.
47. Apparatus, according to claim 46, characterised in that in the vessel there is located an inclined baffle (480), with an open end of a first pipe (460) located below said baffle for introducing into said vessel a flow (H) of an air-vapour mix coming from said container, and with an open end of a second pipe (470) connected to said suction means (11).
48. Apparatus, according to claim 37 or 38, characterised in that said pieces of leather are arranged vertically.
49. Apparatus, according to claim 37 or 38, characterised in that said pieces of leather are arranged horizontally.
50. Apparatus, according to claim 37 or 38, characterised in that said pieces of leather are arranged inclined in any way.
51. Apparatus, according to claim 31 or 37 or 30 or 32, characterised in that itincludes a sonotrode, connected to the container (4), for treating each liquid solution with an ultrasounds beam.
52. Apparatus, according to claim 34 or 38 or 40, characterised in that it includes sonotrodes, one for each of the containers, connected thereto for treating each liquid solution with an ultrasounds beam.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT96BO000233A IT1285917B1 (en) | 1996-05-02 | 1996-05-02 | PROCEDURE FOR OPERATING TREATMENTS ON LEATHER AND SIMILAR AND EQUIPMENT TO IMPLEMENT THIS PROCEDURE |
| ITBO96A000233 | 1996-05-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2253486A1 true CA2253486A1 (en) | 1997-11-13 |
Family
ID=11341369
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002253486A Abandoned CA2253486A1 (en) | 1996-05-02 | 1997-04-23 | Process and apparatus for treating leather and the like |
Country Status (22)
| Country | Link |
|---|---|
| EP (1) | EP0896635A1 (en) |
| CN (1) | CN1219975A (en) |
| AR (1) | AR006948A1 (en) |
| AU (1) | AU727046B2 (en) |
| BA (1) | BA98363A (en) |
| BR (1) | BR9708890A (en) |
| CA (1) | CA2253486A1 (en) |
| CO (1) | CO4870793A1 (en) |
| HR (1) | HRP970218A2 (en) |
| HU (1) | HUP9902462A3 (en) |
| ID (1) | ID17201A (en) |
| IT (1) | IT1285917B1 (en) |
| NZ (1) | NZ332590A (en) |
| PA (1) | PA8429101A1 (en) |
| PL (1) | PL329687A1 (en) |
| SK (1) | SK148398A3 (en) |
| TN (1) | TNSN97072A1 (en) |
| TR (1) | TR199802190T2 (en) |
| UY (1) | UY24535A1 (en) |
| WO (1) | WO1997042350A1 (en) |
| YU (2) | YU48298A (en) |
| ZA (1) | ZA973381B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH694463A5 (en) | 1999-12-10 | 2005-01-31 | Mario Ciucani | Procedure and installation for the treatment of animal skins. |
| ES2177460B1 (en) * | 2001-03-15 | 2003-12-16 | Puig Sueiro Maria Rosa | PROCESSING PROCESSING OF POROUS MATERIALS THROUGH THE VACUUM, AND INSTALLATION AND CORRESPONDING USE. |
| CN100381580C (en) * | 2005-08-26 | 2008-04-16 | 中国皮革和制鞋工业研究院 | Shaped tanning method of leather |
| EP2276862B1 (en) * | 2008-04-16 | 2023-12-20 | Imbox Protection A/S | Method and apparatus for impregnation of items |
| EP3892742B1 (en) | 2020-04-10 | 2024-02-14 | Akaylar Deri Sanayi Ve Ticaret Anonim Sirketi | An adjustable pressure leather and fur processing cabinet and an operation method |
| CN115505651B (en) * | 2022-09-20 | 2023-10-20 | 南京哈恩达斯体育用品有限公司 | Leather pickling device and method for basketball production |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BR8603350A (en) * | 1986-07-16 | 1987-03-31 | Lackovic Nicola | METHOD AND EQUIPMENT FOR DRUM LEATHER TREATMENT |
| DE4120612A1 (en) * | 1991-06-20 | 1992-02-20 | Suesse Harald | Device for thermostable treatment of skins and fleeces - includes sealed rotating drum which uses waste salts from chemical works for preservation |
-
1996
- 1996-05-02 IT IT96BO000233A patent/IT1285917B1/en active IP Right Grant
-
1997
- 1997-04-21 ZA ZA9703381A patent/ZA973381B/en unknown
- 1997-04-23 BR BR9708890A patent/BR9708890A/en unknown
- 1997-04-23 PL PL97329687A patent/PL329687A1/en unknown
- 1997-04-23 CA CA002253486A patent/CA2253486A1/en not_active Abandoned
- 1997-04-23 EP EP97916590A patent/EP0896635A1/en not_active Withdrawn
- 1997-04-23 NZ NZ332590A patent/NZ332590A/en unknown
- 1997-04-23 HU HU9902462A patent/HUP9902462A3/en unknown
- 1997-04-23 TR TR1998/02190T patent/TR199802190T2/en unknown
- 1997-04-23 CN CN97194986A patent/CN1219975A/en active Pending
- 1997-04-23 WO PCT/IB1997/000432 patent/WO1997042350A1/en not_active Application Discontinuation
- 1997-04-23 YU YU48298A patent/YU48298A/en unknown
- 1997-04-23 AU AU25197/97A patent/AU727046B2/en not_active Ceased
- 1997-04-23 SK SK1483-98A patent/SK148398A3/en unknown
- 1997-04-27 HR HRB096A000233A patent/HRP970218A2/en not_active Application Discontinuation
- 1997-04-29 PA PA19978429101A patent/PA8429101A1/en unknown
- 1997-04-29 ID IDP971423A patent/ID17201A/en unknown
- 1997-04-29 UY UY24535A patent/UY24535A1/en unknown
- 1997-04-30 CO CO97023026A patent/CO4870793A1/en unknown
- 1997-04-30 YU YU16497A patent/YU16497A/en unknown
- 1997-05-02 TN TNTNSN97072A patent/TNSN97072A1/en unknown
- 1997-05-02 AR ARP970101824A patent/AR006948A1/en unknown
-
1998
- 1998-10-30 BA BA980363A patent/BA98363A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| AU727046B2 (en) | 2000-11-30 |
| EP0896635A1 (en) | 1999-02-17 |
| HUP9902462A3 (en) | 2000-04-28 |
| TR199802190T2 (en) | 2000-09-21 |
| NZ332590A (en) | 1999-05-28 |
| ID17201A (en) | 1997-12-11 |
| AU2519797A (en) | 1997-11-26 |
| YU16497A (en) | 1999-07-28 |
| CO4870793A1 (en) | 1999-12-27 |
| BR9708890A (en) | 1999-08-03 |
| ITBO960233A0 (en) | 1996-05-02 |
| SK148398A3 (en) | 1999-05-07 |
| AR006948A1 (en) | 1999-09-29 |
| TNSN97072A1 (en) | 1999-12-31 |
| ZA973381B (en) | 1997-11-28 |
| ITBO960233A1 (en) | 1997-11-02 |
| HRP970218A2 (en) | 1998-02-28 |
| YU48298A (en) | 1999-09-27 |
| PL329687A1 (en) | 1999-04-12 |
| PA8429101A1 (en) | 2000-05-24 |
| IT1285917B1 (en) | 1998-06-26 |
| CN1219975A (en) | 1999-06-16 |
| HUP9902462A2 (en) | 1999-11-29 |
| WO1997042350A1 (en) | 1997-11-13 |
| UY24535A1 (en) | 1997-06-18 |
| BA98363A (en) | 2001-09-14 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |