GB2030467A - Screw press for filtering asbestos slurry - Google Patents
Screw press for filtering asbestos slurry Download PDFInfo
- Publication number
- GB2030467A GB2030467A GB7838825A GB7838825A GB2030467A GB 2030467 A GB2030467 A GB 2030467A GB 7838825 A GB7838825 A GB 7838825A GB 7838825 A GB7838825 A GB 7838825A GB 2030467 A GB2030467 A GB 2030467A
- Authority
- GB
- United Kingdom
- Prior art keywords
- tube
- filter tube
- contaminants
- screw
- slurry
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000010425 asbestos Substances 0.000 title claims abstract description 22
- 229910052895 riebeckite Inorganic materials 0.000 title claims abstract description 22
- 239000002002 slurry Substances 0.000 title claims abstract description 20
- 238000001914 filtration Methods 0.000 title description 3
- 239000000356 contaminant Substances 0.000 claims abstract description 26
- 239000006260 foam Substances 0.000 claims abstract description 5
- 239000000835 fiber Substances 0.000 claims description 17
- 238000000034 method Methods 0.000 claims description 15
- 239000006185 dispersion Substances 0.000 claims description 12
- 238000007670 refining Methods 0.000 claims description 8
- 238000005056 compaction Methods 0.000 claims description 4
- 230000003247 decreasing effect Effects 0.000 claims description 2
- 238000007599 discharging Methods 0.000 claims 1
- -1 polypropylene Polymers 0.000 abstract description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 abstract description 3
- 229910000851 Alloy steel Inorganic materials 0.000 abstract description 2
- 229920001875 Ebonite Polymers 0.000 abstract description 2
- 239000004698 Polyethylene Substances 0.000 abstract description 2
- 239000004743 Polypropylene Substances 0.000 abstract description 2
- 229920000573 polyethylene Polymers 0.000 abstract description 2
- 229920001155 polypropylene Polymers 0.000 abstract description 2
- 238000004140 cleaning Methods 0.000 description 7
- 238000001125 extrusion Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000007790 scraping Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000003749 cleanliness Effects 0.000 description 1
- 230000001112 coagulating effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 239000005060 rubber Substances 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
- CWBIFDGMOSWLRQ-UHFFFAOYSA-N trimagnesium;hydroxy(trioxido)silane;hydrate Chemical compound O.[Mg+2].[Mg+2].[Mg+2].O[Si]([O-])([O-])[O-].O[Si]([O-])([O-])[O-] CWBIFDGMOSWLRQ-UHFFFAOYSA-N 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B30—PRESSES
- B30B—PRESSES IN GENERAL
- B30B9/00—Presses specially adapted for particular purposes
- B30B9/02—Presses specially adapted for particular purposes for squeezing-out liquid from liquid-containing material, e.g. juice from fruits, oil from oil-containing material
- B30B9/12—Presses specially adapted for particular purposes for squeezing-out liquid from liquid-containing material, e.g. juice from fruits, oil from oil-containing material using pressing worms or screws co-operating with a permeable casing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/11—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements
- B01D29/31—Self-supporting filtering elements
- B01D29/35—Self-supporting filtering elements arranged for outward flow filtration
- B01D29/356—Self-supporting filtering elements arranged for outward flow filtration open-ended, the arrival of the mixture to be filtered and the discharge of the concentrated mixture are situated on both opposite sides of the filtering element
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/62—Regenerating the filter material in the filter
- B01D29/64—Regenerating the filter material in the filter by scrapers, brushes, nozzles, or the like, acting on the cake side of the filtering element
- B01D29/6469—Regenerating the filter material in the filter by scrapers, brushes, nozzles, or the like, acting on the cake side of the filtering element scrapers
- B01D29/6476—Regenerating the filter material in the filter by scrapers, brushes, nozzles, or the like, acting on the cake side of the filtering element scrapers with a rotary movement with respect to the filtering element
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/88—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices
- B01D29/94—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices for discharging the filter cake, e.g. chutes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D36/00—Filter circuits or combinations of filters with other separating devices
- B01D36/001—Filters in combination with devices for the removal of gas, air purge systems
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Filtration Of Liquid (AREA)
Abstract
A horizontally disposed perforated cylindrical tube 18 has a helical screw 40 disposed therewithin, and a flanged jacket 10 concentric with and spaced outwardly therefrom. An asbestos slurry is continuously fed into the tube and refined slurry is drawn through the perforations 24 by a suction pump connected to the jacket while contaminants are moved by the screw to the outlet end of the tube where they are compacted and removed through a spring loaded discharge door 36. The perforations 24 may be circular, square or rectangular and are preferably tapered. Screw 40 has its outer periphery polished or chrome plated or equipped with flexible replacable strips of hard rubber, polypropylene, polyethylene, P.T.F.E., or alloy steel. A vacuum gauge in the suction line monitors the clogging of perforations 24. A constant head of slurry is maintained in feed reservoir 28 by an overflow or float control device. Vent tube 46 bleeds off air and foam. <IMAGE>
Description
SPECIFICATION
Apparatus and method for refining asbestos dispersions
This invention relates to a method and apparatus for the removal of contaminants from colloidally dispersed chrysotile asbestos fibres.
The invention more particularly relates to method and apparatus for refining such dispersions in a continuous manner and much more efficiently than heretofore possible.
In the production of asbestos yarn as taught, for example, by Novak and Orzechowski in U.S.Patent 3,453,818, the yarn is formed by extruding colloidally dispersed asbestos fibers through extrusion nozzles into a coagulating liquid. The exit orifices of these extrusion nozzles can vary in both size and shape.
For example, circular orifices can range from 0.020 inch to 0.125 inch (0.0508 to 0.3175 cm). Orifices of elliptical, triangular or rectangular shape may have minimum openings within the above mentioned range of 0.020 to 0.125 inch.
The difficulty arises in that bagged asbestos as received for processing into yarn contains from 0.1% to 10.0% of foreign material or contaminants such as rock, wood, rubber, clots, unopened bundles of asbestos, spicules, wire, and the like. The physical dimensions of such contaminants are larger than the orifice or the slits of the extrusion nozzles. Therefore, if such particles are not removed, they will cause the nozzle orifices to become plugged, resulting in discontinuities in the formation of the yarn and interruption of yarn production. Nozzle plugging necessitates removal of the nozzles for cleaning by probing, backflushing, washing, etc.
There are many known methods of refining asbestos dispersion, none of which are entirely satisfactory. In one such prior art method, the dilute colloidal asbestos slurry is centrifugally forced through slotted screens. Another method comprises the forcing of the unrefined slurry through a filter screen having small holes with definitely prescribed
spacing. The reason for the criticality of the hole
diameter and spacing is that the long asbestos fibers
present in dispersions suitable for yarn making tend to more rapidly clog the screening holes. In any event, the contaminants themselves, along with a certain amount of asbestos fibers, tend to clog the filter holes. Prior art refining devices, therefore, have
utilized scrapers of various types which are moved
across the filtering screen surface periodically for the
purpose of keeping the screen holes open.
Despite such attempts to keep the screen holes
open, plugging still occurs. In fact, cleaning of
known prior art refining devices may be required as
often as once per hour if excessively dirty fibers are
introduced into the system. Even with fibers or
normal average cleanliness, sufficient clogging
occurs to require daily cleaning.
The apparatus and method#of the present inven
tion overcomes many of the disadvantages of prior
art refining systems. Broadly, the present invention
contemplates physically separating undesirable par
ticles, or contaminants, from an incoming slurry of colloidally dispersed asbestos fibers, drawing off the refined dispersion for further processing, and conveying the contaminants toward a discharge end of the device where they are compacted and automatically ejected responsive to compaction pressure.The device is continuous in operation and virtually self-cleaning, thereby having greater efficiency and being more economical to operate than prior art devices Other advantages will be apparent from the following description of the preferred embodiment of the apparatus and method, and the accompanying drawings wherein:
Figure 1 is an elevational view, partially in section, of the apparatus for carrying out the process of this invention;
Figure 2 is an end view of the discharge end of the apparatus of Figure 1; and
Figure 3 and Figure 4 are fragmentary sectional views showing preferred shapes of filtering holes.
Referring to Figure 1, the refining apparatus comprises a horizontally disposed, preferably cylindrical jacket 10 supported by suitable framework 12.
For assembly and maintenance purposes, the jacket 10 may be formed in two halves, each provided with flanges 14 and fastened together by bolt and nut assemblies 16. The jacket obviously may be other than cylindrical, the cross sectional contour not being critical.
A cylindrical perforated tube 18 is disposed within the jacket 10 and radially spaced therefrom to form a chamber 20 closed at both ends by walls 22. The tube 18 is provided with a plurality of filter holes 24 around the entire periphery, the holes preferably being circular in cross section but alternately may be square or rectangular. The holes may be of a necessary suitable size dependent on the size of the nozzles which will be used in a subsequent yarn making process and can range between 0.001 to 0.125 inch (0.00254 to 0.3175cm) from edge to edge at the smallest part.
It has been found that there is less tendency for asbestos fibers to clog the holes if the holes are formed with at least a partial taper increasing in cross-sectional area toward the outside of the tube 18 as shown in Figure 1. Two possible embodiments of filter holes are shown in Figure 3 and Figure 4.
Thefiltertube 18 projects beyond jacket 10 atthe inlet end 26 and communicates with a supply reservoir 28 having inlet means 30 and drain means 32.
The filter tube 18 also projects beyond jacket 10 at the outlet or discharge end 34 which is closed except for a spring biased discharge door 36 held normally in closed position by spring 38.
Received within the tube 18 and extending the full length thereof is a screw 40 which may be driven through gearing at variable speeds by any suitable
power source (not shown). The outer periphery of the screw is preferably polished and chrome plated for hardness so as to prevent binding as it rotates within the filter tube and also to provide good scraping action along the full length of the tube.
While in the preferred embodiment the screw
periphery should be in contact with the inner wall of the tube, it will be appreciated that as a practical matter this condition will be difficult to achieve.
However, any clearance which will be provided should be held to a maximum of about 0.025 inch (0.0635 cm) to ensure positive removal of fibers and residue from the holes and to provide positive conveyance of debris to the discharge end of the tube as will be explained later.
As mentioned heretofore, the periphery of the screw conveyor may be chrome plated, or alternately may be case hardened or equipped with flexible, replaceable strips of hard rubber, Teflon (Registered
Trade Mark), polypropylene, polyethylene, alloy steel, or the like so as to provide good scraping characteristics.
It has been found that air and foam at times accumulate toward the discharge end of filter tube 18. To alleviate this condition, a vent tube 46 and a shut-offvalve47 may be provided, the venttube communicating with the filter tube 18 to bleed off foam and air from the compacting dispersion.
In operation, unrefined dispersion, containing about 0.1% to 4.0% solids, enters the device through inlet 30 and reservoir 28 in which a constant level head, well above the horizontal tube entrance, is maintained by any conventional means such as an overflow or a float control device (not shown). The head level must be high enough so that a vacuum seal may be maintained on the filter holes 24 as will become evident.
The unrefined dispersion, or slurry, is drawn into the tube 18 and fills it completely. A variable speed pump (not shown) connected to an outlet pipe 44 creates a suction in chamber 20 and pulls refined dispersion through the filter holes of tube 18 into the chamber 20 and from there removes it through outlet pipe 44forfurther processing such as spinning into yarn.
Simultaneously, the screw 40 is rotated at the desired speed and conveys the debris and contaminants, which are too large to pass through filter holes 24, to the discharge end 34 of the tube. When the residue of contaminants becomes sufficiently compacted and de-watered, that is to a concentration of about 20% to 40% solids, its viscosity permits it to be rotated by the action and strategic location of the screw. As additional residue accumulates, pressure is built up so as to force open the spring biased discharge door 36 through which the residue is continuously expelled to be properly collected and disposed of. It will be noted that preferably the screw will extend to the extreme outlet end of tube 18 to ensure that the screw thrust will overcome the friction between the residue and the tube wall and thus eject the residue.
The above described apparatus and method refines colloidal asbestos dispersions much more quickly and efficiently than prior art devices. Furthermore, it has been determined that the apparatus of this invention requires very little down time for cleaning purposes. For example, it has been thought that the distance between filter holes was extremely critical and had to be greater than the length of the asbestos fibers in the slurry. Utilizing the screw means of the present invention, the distance between filter holes may be reduced to about three
quarters of the length of the asbestos fibers. This
spacing is adequate, because of the greater wiping
action of the screw, to prevent "bridging" of fibers
between adjacent holes and also allows about a 25%
increase in effective filter area.
It should be noted that, if desired, the effectiveness
of the continuous cleaning of the filter holes can be
monitored by means of a vacuum gage (not shown)
installed in the suction line, or outlet pipe, 44.
Clogged holes will result in an increased vacuum * while the cleaning of holes will result in a decreased vacuum.
Claims (6)
1. Apparatus for removing contaminants from a slurry of colloidally dispersed asbestos fibers comprising: a horizontally disposed jacket; a perforated filter tube internally of said jacket, the filter tube having an inlet end and an outlet end and being spaced from the jacket to form a chamber therebetween; a screw disposed for rotation within the filter tube; means for feeding slurry into the filter tube; suction means associated with the chamber for drawing refined dispersion through the perforations from the filter tube into the chamber while retaining the contaminants in the filter tube; means for rotating the screw to compact the contaminants at the discharge end of the filter tube; and means for removing compacted contaminants from the discharge end of the filter tube.
2. Apparatus as claimed in claim 1 in which the jacket is cylindrical, and the filter tube is cylindrical, and concentric with the jacket.
3. Apparatus as claimed in claim 2, wherein the outer periphery of the screw is in sliding fit relationship with the filter tube.
4. Apparatus as claimed in claim 2, wherein the outer periphery of the screw is spaced from the filter tube by an amount in the range of 0.00508 cm to 0.0635 cm.
5. Apparatus as claimed in any one of claims 1 to 4, wherein the means for removing contaminants from the discharge end of the filter tube comprises means for automatically ejecting the contaminants responsive to compaction pressure.
6. Apparatus as claimed in claim 5 and substantially as hereinbefore described with reference to and as illustrated in figures 3 and 4 of the accompanying drawings.
6. Apparatus as claimed in claim 5 and including a vent tube communicating with the filter tube to bleed off air and foam from the residue being compacted.
7. Apparatus as claimed in claim 5, wherein the pressure responsive means comprises a spring biased discharge door.
8. Apparatus as claimed in any one of claims 1 to 7, wherein the performations are separated from each other by an amount approximately equal to three-quarters of the length of the asbestos fibers in the slurry.
9. Apparatus as claimed in any one of claims 1 to 8, wherein the perforations decrease in size in direction radially inwardly of the filter tube.
10. Apparatus as claimed in any one of claims 1 to 9, wherein the screw extends to the extreme outlet end of the tube.
11. A method of refining a slurry of colloidally dispersed asbestos fibers and contaminants, comprising the steps of: physically separating the containants from the slurry; conveying the contaminants to the discharge end of a screw conveyor; compacting the contaminants at said discharge end; and discharging the contaminants responsive to compaction pressure.
12. A method of removing contaminants from a slurry of colloidally dispersed asbestos fibers, comprising the steps of: feeding the contaminated slurry into a cylindrical, horizontally disposed tube having helical screw means extending for the length of the tube, said screw means being in close proximity with the inner surface of the tube; forcing the slurry out of the tube through a plurality of closely spaced openings in the wall of the tube, the openings being of a size and having a spacing so as to retain the contaminants in the tube; simultaneously rotating the screw means to move the containants to the discharge end of the tube and compact them at said discharge end; and then removing said compacted contaminants from said tube.
13. A method as claimed in claim 11, wherein the removal of said compacted containants is responsive to the pressure of compaction of said contaminants by said screw means.
14. Apparatus as claimed in claim 1 and substantially as hereinbefore described with reference to and as illustrated in Figures 1 and 2 of the accompanying drawings.
15. Apparatus as claimed in claim l4andsub- stantially as hereinbefore described with reference to and as illustrated in Figure 3 or Figure 4 of the accompanying drawings.
16. A method as claimed in claim 11 and substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.
New claims or amendments to claims filed on 21.
Nov. 1979.
Superseded claims 1-16.
New or amended claims:
CLAIMS
1. Apparatus for removing contaminants from a slurry of colloidally dispersed asbestos fibers comprising: a horizontally disposed jacket; a perforated filter tube internally of said jacket, said perforation decreasing in size in direction radially inwardly of the filter tube and being spaced from each other by an amount approximately equal to three-quarters of the length of the asbestos fibers in the slurry, the filter tube having an inlet end and an outlet end and being spaced from the jacket to form a chamber therebetween; a screw disposed for rotation within the filter tube; means for feeding slurry into the filter tube; suction means associated with the chamber for drawing refined dispersion through the perforations from the filter tube into the chamber while retaining the contaminents in the filter tube; means for rotating the screw to compact the contaminants at the discharge end of the filter tube; and means for removing compacted contaminants from the discharge end of the filter tube.
2. Apparatus as claimed in claim 1, wherein the outer periphery of the screw is in sliding fit relationship with the filter tube.
3. Apparatus as claimed in claim 1, wherein the outer periphery of the screw is spaced from the filter tube by an amount in the range of 0.00508 cm to 0.0635 cm.
4. Apparatus as claimed in any of claims 1 to 3, and including a vent tu be communicating with the filter tube to bleed off air and foam from the residue being compacted.
5. Apparatus as claimed in claim 1 and substantially as hereinbefore described with reference to and as illustrated in Figures 1 and 2 of the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7838825A GB2030467B (en) | 1978-09-30 | 1978-09-30 | Screw press for filtering asbestos slurry |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7838825A GB2030467B (en) | 1978-09-30 | 1978-09-30 | Screw press for filtering asbestos slurry |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2030467A true GB2030467A (en) | 1980-04-10 |
| GB2030467B GB2030467B (en) | 1982-11-10 |
Family
ID=10500030
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7838825A Expired GB2030467B (en) | 1978-09-30 | 1978-09-30 | Screw press for filtering asbestos slurry |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2030467B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160040358A1 (en) * | 2013-03-15 | 2016-02-11 | Hans-Joachim Boltersdorf | Screw press with a delivery pipe and method for operating a screw press |
| US20190217567A1 (en) * | 2018-01-12 | 2019-07-18 | Andreas Wecker | Tunable Seed Oil Expeller Press |
| US11077635B2 (en) * | 2018-01-12 | 2021-08-03 | Andreas Wecker | Expeller for seed oil press |
-
1978
- 1978-09-30 GB GB7838825A patent/GB2030467B/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160040358A1 (en) * | 2013-03-15 | 2016-02-11 | Hans-Joachim Boltersdorf | Screw press with a delivery pipe and method for operating a screw press |
| US20190217567A1 (en) * | 2018-01-12 | 2019-07-18 | Andreas Wecker | Tunable Seed Oil Expeller Press |
| US11077635B2 (en) * | 2018-01-12 | 2021-08-03 | Andreas Wecker | Expeller for seed oil press |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2030467B (en) | 1982-11-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |