EP1874479A1 - Apparatus for treatment of a polluted liquid, particularly for treatment of polluted water from production residues of non-woven fabric - Google Patents

Abstract

Apparatus (6) for treatment of a polluted liquid, particularly for treatment of polluted water from production residues of non-woven fabric, comprising a chamber (7) that contains at least a treatment chamber (8) to treat this polluted liquid, feed means (9) in order to feed this chamber with polluted liquid and discharge means (10) to discharge from this chamber (8) treated liquid. Apparatus (6) still comprises also flotation means (11) housed in said tank in order to carry out at least a flotation phase on polluted liquid contained in this chamber in order to eliminate coarse residues and filtration means (12) housed in this tank in order to carry out at least a filtration phase of polluted liquid contained in this chamber in order to eliminate minute residues. Peculiarity of this apparatus is that the flotation means (11) and the filtration means (12) act together on polluted liquid in this chamber (8) so that the filtration and flotation phases on said polluted liquid take place in only one treatment chamber (8) .

Description

APPARATUS FOR TREATMENT OF A POLLUTED LIQUID, PARTICULARLY FOR TREATMENT OF POLLUTED WATER FROM PRODUCTION RESIDUES OF NON-WOVEN FABRIC

DESCRIPTION The present invention relates to an apparatus for treatment of a polluted liquid, particularly for treatment of polluted water from production residues of non-woven fabric, to be used preferably, but not exclusively, in non-woven fabric production plants having a base of a pulp of cellulose and cotton. As well known, this liquid, preferably water, used in manufacture processes of non-woven fabric, is treated to eliminate production residues in order to make it apt to be used again in these same processes. The treatment of this liquid is carried out by means of a first flotation phase to take away from this liquid coarse residues and a second filtration phase to take away from this liquid remaining minute residues. As a result, the apparatus of polluted liquid treatment is made up respectively by a flotation apparatus and by a filtration apparatus, which are separate and placed one after the other. Flotation apparatus includes substantially a tank which makes up a flotation chamber for flotation of polluted liquid. Suitable feed means feed chamber with polluted liquid to be processed and suitable discharge means take out polluted liquid that has undergone flotation treatment. Filtration apparatus is made up by a tank without bottom and by filtration means made of a belt placed on the tank bottom which define together with retaining tank walls a filtration chamber for filtration of polluted liquid previously subjected to a flotation treatment.

Between flotation apparatus and filtration one is also provided an intermediate container for collection supplied by discharge means, transferring means that take out liquid contained in the container and send it to the filtration means and a collection end tank of liquid treated arranged in the bottom with reference to the filtration apparatus.

The operation of such an apparatus develops as described in the following.

Feed means introduce continuously polluted liquid to be treated in the flotation chamber from which discharge means take out polluted liquid which has undergone flotation treatment and carry it to the intermediate gathering tank. Transferring means take out polluted liquid which has to undergo filtration and send it to filtration tank from which it goes out from its bottom finally treated to be stored in the gathering tank underneath. From this last one the treated liquid is again inserted in production process of non-woven fabric.

A first drawback found out by manufacturers of these treating apparatuses is connected to high costs necessary for their construction owing to materials and technologies used.

A second drawback found out by users of these apparatuses is to be found in high quantity of space used by these last ones inside industrial manufacturing plants. Really, these apparatuses are generally very big both when considered one by one or all together.

The aim of present invention is to set up a treatment apparatus for polluted liquid, particularly for treatment of polluted water from production residues of non-woven fabric, able to solve the drawbacks found in apparatuses of the prior art.

Within this aim, one of the objects of this invention is to set up a treating apparatus within small construction costs.

Another object of this invention is set up a treating apparatus of small dimensions.

Another object of this invention is to set up a treatment apparatus that does not need special requirements in installation rooms.

Not last object of this inventions is to set up a treatment apparatus that does not require more frequent maintenance calls or more costly with reference to apparatuses of prior art.

This aim, these and other objects that will be better apparent in the following, are reached by a treatment apparatus for polluted liquid, particularly for treatment of polluted water from production residues of non- woven fabric according to the appended claims.

According to main features of the invention, treatment apparatus comprises only one tank for treatment of polluted liquid connected to feed and discharge means and that comprises flotation and filtration means able to operate together on the polluted liquid contained in the chamber. In this way, only one treatment chamber is required instead of two separate chambers for the treatment which are typical of the prior art. This allows a strong reduction of production costs of the apparatus and a good reduction of dimensions.

Further characteristics and advantages will be better understood from a description of a preferred embodiment of an apparatus for treatment of polluted liquid, particularly for treatment of polluted water from production of non-woven fabric, described only for explanation purposes, but not restrictive, in the appended five drawings in which: figure 1 shows a side view of the apparatus according to the invention; figure 2 shows an upper view of the apparatus of the preceding figure; - figure 3 shows a prospective view of apparatus of the preceding figures according to a first point of view; figure 4 shows a prospective view of apparatus of the preceding figures according to a second point of view. figure 5 shows a section view, according to plane of line V-V of figure 4, of the apparatus of the preceding figures.

With reference to the figures of the appended drawings, the apparatus for treatment of polluted liquid, particularly for treatment of polluted water from residues of production of non-woven fabric, as a whole indicated with reference number 6, includes first of all a tank 7 which includes at least a treatment chamber 8 to carry out treatment of polluted liquid. Apparatus 6 includes also feed means, as a whole indicated with reference number 9, that continuously feed polluted liquid to be treated in treatment chamber 8 and discharge means, as a whole indicated by reference number 10, that discharge continuously treated liquid from treatment chamber 8. Apparatus 6 is still provided with flotation means, as a whole indicated by reference number 11 , which are housed in tank 7 thus to set up at least a flotation phase on polluted liquid which is found in treatment chamber 8. The above mentioned flotation phase has the purpose of eliminating the coarse residues from polluted liquid. Apparatus 6 is also provided with filtration means, as a whole indicated with reference number 12, housed in the tank 6 thus to carry out at least a phase of filtration on polluted liquid which is found in treatment tank 8. The above filtration phase has the purpose of eliminating minute residues from polluted liquid that in the flotation phase is not possible to take out. According to this invention, flotation means 11 and filtration means 12 operate together on polluted liquid which is found in the treatment chamber 8. Thus, the above mentioned flotation and filtration phases of polluted liquid take place advantageously only in the treatment chamber 8. In details, walls of treatment chamber 8 are made up by containing walls of tank 7 and the bottom is substantially defined by the filtration means 12. The above mentioned feed means 9 are made of a feeding tube 13 that connects a gathering tank (not shown) of polluted liquid to be treated or directly the production apparatus of non-woven fabric (not shown) of polluted liquid with the tank 6. On this tube 13 there are in sequence a pressure generating unit 14 that has the purpose to increase feeding pressure of polluted liquid and a mixer 15 that has the purpose of mixing intimately polluted liquid with oxygen for this purpose blown-in in feed means 9 in order to allow the flotation phase. The above mentioned discharge means 10 are in their turn made up by a discharge tube 16 on which there are an interception valve (not shown) that operates usually open and at least a pneumatic regulation valve (not shown). In details, this regulation pneumatic valve has the purpose to keep constant level inside tank 6 because this at least partially strangles the discharge. The above mentioned flotation means 11 are made up in their turn by a plurality of flotation cells 17 which are fed by the feed means 9 that take polluted liquid into the treatment chamber 8. In details, flotation cells 17 are made of box shaped bodies 18, made thinner and bent in same direction in order to introduce liquid in the same direction. The flotation means 11 include also mechanical removal means 19 able to mechanically remove coarse residues which are formed on liquid surface during the flotation phase. In details, these mechanical removal means 19 are made up by a first and a second drive belt 20a and 20b which are parallel applied to the edges of a first pair of parallel and opposite walls of the containment walls of the tank 7 and by a plurality of scraping blades 21 supported and driven by the above mentioned driving belts 20a and 20b. These scraping blades 21 during their work way take out coarse residues of flotating liquid lying on liquid surface being treated. Suitably, the mechanical removal means 19 are connected to collection means 22, in which gathering blades 21 release at end of their work cycle the accumulated residues. These collection means 22 are simply made by a small collection tank of coarse residues provided with a discharge. At their turn, the filtration means 12 are placed lower than the flotation means 11 and are, with advantage, made up by a moving filtering carpet 23 and by a network shaped support 24 which carries this carpet 23. This last one is made up by a ring shaped belt in a material suitable for filtration hung to a first and a second forward moving bar 25a and 25b connected to edges of a second pair of parallel and opposite walls of the containment walls of the tank 7. In the embodiment shown in the drawings, the first moving bar 25 a is driven by a lateral electric motor 26 while moving bar 25 b can freely rotate on its own supports. In this case, the apparatus 6 includes a plurality of spraying nozzles (not shown) provided near the first and second moving bar 25 a and 25 b which look towards the back wall of the belt. These nozzles give off as many contrasting washing jets in order to carry out continuously a contrasting washing of the belt in vicinity of the immersion and emersion area of belt into/from the treatment liquid. In an alternative execution not shown, moving filtering belt 23 is made up by a material suitable for filtration supplied by a feeding rotating roll and rewound on a rewinding rotating roll used as a substitution of moving bars 25a and 25b. Suitably, the movement of the belt 23 is carried out as a function of liquid level to be treated reached inside of the chamber 8. Really, the apparatus 6 is provided with a level measurement device of known art (not shown) that acts on electric motor 26 in the following way so that if level of liquid to be treated grows with reference to standard level because filtering moving belt 23 exhausts its own filtration capability, then the carpet is moved forward in order to substitute exhausted belt with a new fresh belt in order to restore the level. Finally, the apparatus 6 is set up to operate when needed only as a flotation apparatus. As a matter of fact, it is provided with a supplementary tube 27, that connects treatment chamber 8 with above mentioned discharge tube 16 in a position (not shown) between the interception valve and the regulation valve and it is provided with a supplementary interception valve (not shown) located along the above mentioned supplementary tube and kept usually closed. As a result, in case the interception valve is closed and the supplementary interception valve is opened, supplementary tube takes out of treatment chamber 8 polluted liquid that has only undergone flotation phase and takes it to discharge tube 16. The operation of apparatus 6 develops as described in the following:

Polluted liquid is taken by feed means 9 either directly from production apparatus (not shown) of non-woven fabric or from an intermediate storing tank (not shown) for liquid to be treated and moved by means of feeding tube 13, through pressure generating equipment 14 where it is pressurized and through mixer 15 where it is mixed with blown oxygen, to flotation cells 18. From these last ones, liquid goes out into treatment tank 8 as long as it is filled up. In this condition the filtration and the flotation phases take place, as follows. Oxygen small bubbles which are in the liquid adhere to surfaces of granules of coarse residues and make them go upward and, as a result, they are kept on surface of liquid going to be treated. Here, the mechanical removal means 11 provide to remove these coarse residues and to take them into the collection means 22. In details, scraping blades 21 in their work way which is regulated by moving driving belts 20a and 20b accumulate coarse residues which at the end of their work way are released in small tank of the collection means 22. At the same time, polluted liquid already purified from coarse residues undergoes filtration phase. As a result, liquid goes through filtering moving carpet 23 leaving on its surface minute residues. Liquid in this way treated is accumulated on the bottom of tank 6 from where it goes out through the discharge means 10. Really, the discharge tube 16 gathers treated liquid and sends it either to an intermediate accumulation tank (not shown) for treated liquid or directly to production apparatus of non-woven fabric. It is in practice found out that apparatus for treatment of polluted liquid, particularly for treatment of polluted water from production residues of non-woven fabric satisfy the aim and the object established. Particularly, the treatment apparatus above described can be built with limited costs and requires limited dimensions with reference to apparatuses of known art. Further, this apparatus does not require special arrangements inside installation rooms. Finally, the treatment apparatus does not require maintenance calls more frequent or more costly with reference to apparatuses of known art described above.

The apparatus according to this invention admits many changes and variations, all included in the limits of the same invention concept.

In the practical embodiments, the materials used, shapes, dimensions and execution details could differ from those here given, but to these equivalent from a technical point of view, without for this reason to be considered out of the scope of the invention.

Claims

1. Apparatus for treatment of a polluted liquid, particularly for treatment of polluted water from production residues of non-woven fabric, comprising a tank that contains at least one treatment chamber in order to treat said polluted liquid, feed means in order to feed said chamber with polluted liquid and discharge means in order to discharge from said chamber treated liquid, flotation means housed in said tank in order to carry out at least one phase of flotation on said polluted liquid contained in said chamber in order to eliminate coarse residues and filtration means housed in said tank in order to carry out at least one phase of filtration on said polluted liquid contained in said chamber in order to eliminate minute residues, characterized in that said flotation means and said filtration means operate together on polluted liquid contained in said chamber so that these flotation and filtration phases on said polluted liquid take place in only one treatment chamber. 2) Apparatus, according to claim 1 , characterized in that said chamber is defined in its sides by containing walls of said tank and in the bottom is defined by said filtration means.

3) Apparatus, according to claims 1) and 2), characterized in that said feed means comprise a feeding tube, at least a pressure generating equipment in order to increase feeding pressure of said polluted liquid and at least a mixer in order to intimately mix said polluted liquid with oxygen inserted in said feed means.

4) Apparatus, according to one or more of the preceding claims, characterized in that said discharge means comprise a discharge tube, at least an interception valve usually open and at least one pneumatic regulation valve along said discharge tube, said regulation valve maintains constant the level inside said discharge tank because it strangles at least partially the discharge.

5) Apparatus, according to one or more of the preceding claims, characterized in that said flotation means comprise a plurality of flotation cells fed by said feed means that insert said polluted liquid in said chamber, mechanical removal means in order to remove mechanically said coarse residues of polluted liquid contained in said chamber during said flotation phase and collection means in order to collect said coarse residues fed in their turn by said mechanical removal means.

6) Apparatus, according to one or more of the preceding claims, characterized in that said flotation cells are made up by box shaped bodies, made thin and bent in the same direction in order to introduce said liquid in said chamber in same direction.

7) Apparatus, according to one or more of the preceding claims, characterized in that said mechanical removal means comprise a first one and a second driving belt which are parallel and connected to edges of a first pair of parallel and opposite walls of said containment walls, and comprise a plurality of scraping blades supported and driven by said driving belts that in their work way remove said coarse residues from liquid surface and release them at the end of the above mentioned work way in said collection means.

8) Apparatus, according to one or more of the preceding claims, characterized in that said collection means comprise a small tank for collecting said coarse residues provided with a discharge.

9) Apparatus, according to one or more of preceding claims, characterized in that said filtration means are located at the bottom of said flotation means.

10) Apparatus, according to one or more of preceding claims, characterized in that said filtration means comprise a filtering moving carpet and a network shaped support that carries said carpet.

11) Apparatus, according to one or more of preceding claims, characterized in that said filtering moving carpet is made up of a ring shaped belt in suitable material for filtration hung to a first and a second driving bar connected to the edges of a second pair of parallel and opposite walls of said containing walls.

12) Apparatus, according to one or more of the preceding claims, characterized in that it comprises a plurality of spraying nozzles placed in vicinity of said first bar and of said second forward moving bar that emit washing jets against said ring shaped belt.

13) Apparatus, according to one or more of the preceding claims characterized in that filtering moving carpet is made of a belt in a material which is suitable to filtration unwound from a turning feeding roll and rewound on a rewinding turning roll which are used instead of said forward moving bars.

14) Apparatus, according to one or more of the preceding claims, characterized in that forward moving of that moving carpet is a function of liquid level reached inside said tank. 15) Apparatus, according to one or more of the preceding claims, characterized in that said discharge means comprise a discharge tube, at least one interception valve usually open and at least a pneumatic regulation valve along said tube, said regulation valve keeping constant the level inside said tank because it strangles at least partially the discharge. 16) Apparatus, according to one or more of the preceding claims, characterized in that it comprises a supplementary tube that connects said treating chamber to said discharge tube in a position downstream of said interception valve and upstream of said regulation valve and a supplementary interception valve usually closed along said supplementary tube so that, when said interception valve is closed and said interception supplementary valve is open, said supplementary tube takes out polluted liquid that has only undergone said flotation phase from said treating chamber and takes it in said discharge tube.