GB2051598A - Apparatus for dewatering sludges - Google Patents
Apparatus for dewatering sludges Download PDFInfo
- Publication number
- GB2051598A GB2051598A GB7917277A GB7917277A GB2051598A GB 2051598 A GB2051598 A GB 2051598A GB 7917277 A GB7917277 A GB 7917277A GB 7917277 A GB7917277 A GB 7917277A GB 2051598 A GB2051598 A GB 2051598A
- Authority
- GB
- United Kingdom
- Prior art keywords
- belt
- guide plate
- sludge
- filter belt
- belts
- 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
- 239000010802 sludge Substances 0.000 claims abstract description 16
- 239000000463 material Substances 0.000 claims abstract description 12
- 239000007788 liquid Substances 0.000 claims description 9
- 239000004033 plastic Substances 0.000 claims description 3
- 229920003023 plastic Polymers 0.000 claims description 3
- -1 polytetrafluorethylene Polymers 0.000 claims description 3
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 2
- 229910002804 graphite Inorganic materials 0.000 claims description 2
- 239000010439 graphite Substances 0.000 claims description 2
- CWQXQMHSOZUFJS-UHFFFAOYSA-N molybdenum disulfide Chemical compound S=[Mo]=S CWQXQMHSOZUFJS-UHFFFAOYSA-N 0.000 claims description 2
- 238000005406 washing Methods 0.000 description 3
- 239000004677 Nylon Substances 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 229920001778 nylon Polymers 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000000126 substance 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
- B30B9/24—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 an endless pressing band
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D33/00—Filters with filtering elements which move during the filtering operation
- B01D33/04—Filters with filtering elements which move during the filtering operation with filtering bands or the like supported on cylinders which are impervious for filtering
- B01D33/042—Filters with filtering elements which move during the filtering operation with filtering bands or the like supported on cylinders which are impervious for filtering whereby the filtration and squeezing-out take place between at least two filtering bands
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D33/00—Filters with filtering elements which move during the filtering operation
- B01D33/056—Construction of filtering bands or supporting belts, e.g. devices for centering, mounting or sealing the filtering bands or the supporting belts
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D33/00—Filters with filtering elements which move during the filtering operation
- B01D33/44—Regenerating the filter material in the filter
- B01D33/48—Regenerating the filter material in the filter by flushing, e.g. counter-current air-bumps
- B01D33/50—Regenerating the filter material in the filter by flushing, e.g. counter-current air-bumps with backwash arms, shoes or nozzles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D33/00—Filters with filtering elements which move during the filtering operation
- B01D33/58—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element
- B01D33/62—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element for drying
- B01D33/64—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element for drying by compression
- B01D33/646—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element for drying by compression by pressure rollers
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Treatment Of Sludge (AREA)
Abstract
Apparatus for dewatering fine fragile sludges comprises a pair of filter belts (1, 2) which are caused to follow a curved path of reducing radius so that the sludge while carried between the two belts is subjected to a gradual and continual increase in pressure. The curved path is preferably defined by a portion of a cornu spiral. The belts are constrained to follow the curved path by bringing the upper belt into direct or indirect contact with an apertured curved, guide plate (13). The plate may be coated with a lubricious material or roller bearings may be provided between the belt and the plate. <IMAGE>
Description
SPECIFICATION
Apparatus for dewatering sludges
This invention relates to apparatus for dewatering sludges and more particularly to apparatus which can be used for dewatering fine fragile sludges that even when flocculated with chemical conditioners do not form a sufficiently strong bridge of flocs over filter apertures so that when they are subjected to a sudden pressure increase the flocs break down and either pass through the filter apertures or block or blind the apertures.
In conventional dewatering apparatus, sludges, usually after treatment to cause them to flocculate, are squeezed between a pair of filter belts under increasing pressure, the pressure being applied by a series of pressure rollers around which the belts pass. The application of pressure to the sludge by means of a series of rollers means that the pressure is increased stepwise and the resultant sudden pressure increases can cause flocs produced from fragile sludges to break down into fine particles that will pass through or block the apertures in the filter belts. Such flocs, however, will not break down when the pressure applied to the floc gradually increases from a minimum at the feed end of the apparatus to a maximum at the output end.No apparatus, however, has yet been devised for dewatering fine fragile sludges with the necessary gradual and continual increase of pressure necessary to prevent breakdown of the floc.
This invention provides apparatus for dewatering fine fragile sludges in which the sludge while carried between a lower filter belt and an upper filter belt is subjected to a gradual and continual increase in pressure by causing the belts to follow a curved path of reducing radius. The curved path is advantageously defined by a portion preferably the beginning of a cornu spiral.
The belts are preferably constrained to follow the prescribed path by bringing them into direct or indirect contact with a guide plate shaped to the desired form.
The guide plate may be coated with an lubricious material, such as graphite, molybdenum disulphide, a filled plastics material such as nylon, or polytetrafluorethylene, in which case the upper filter belt may be in direct contact with the guide plate or there may be provided other anti-friction means such as closely packed ball or roller bearings between the guide plate and the upper filter belt. Ball or roller bearings used in the apparatus are preferably made from a lubricious plastics material such as polytetrafluorethylene or nylon.
The curve of the guide plate, which as mentioned hereinbefore is preferably a part of a cornu spiral, maybe generated by the "Fresnel" integrals:~
The guide plate is provided with a plurality of apertures passing through it to allow passage of the liquid squeezed out of the sludge and passing through the filter belt. This liquid is drained off from the upper surface of the guide plate. Liquid passing through the lower filter belt is handled in the conventional manner.
The apparatus of the invention may form the first stage of a multi-roll belt filter since it produces a stabilised filter press cake from a fragile sludge which press cake can be treated further to decrease the liquid content therein by passing it through conventional roll belt dewatering apparatus without the risk of breakdown of flocs occurring.
The invention will now be described in greater detail by way of example with reference to the drawings, in which:~
Figure 1 is a diagrammatic side view of dewatering apparatus embodying the invention,
Figure 2 is an enlarged section of a part of the apparatus shown Fig. 1, and
Figure 3 is an enlarged section of a part of a modified apparatus according to the invention.
As shown in Fig. 1 of the drawings the dewatering apparatus of the invention has a lower filter belt 1 and an upper filter belt 2 between which the pulp to be dewatered is squeezed during passage through the apparatus. The lower filter belt 1 passes round rolls 3, 4 and 5. Rolls 3 and 5 are idler rolls while roll 4, may be an idler roll or may be a driven roll. Roll 5 is connected to hydraulic belt tensioning means 6 for adjusting the tension in the lower filter belt. Between rolls 4 and 5 the belt passes over a steering roll which is provided to keep the belts tracked and to prevent their coming off the rolls.
Within the run of the belt is provided water spray means 8 for applying water to the run of the belt between rolls 3 and 5 to remove remnants of dewatered sludge remaining on the belt as it passes back to roll 5 where it picks up additional sludge to be dewatered.
Washing liquid, together with liquid that is filtered from the sludge through the lower filter belt leaves the apparatus through a discharge pipe 9.
The upper filter belt 2 passes round a driven roll 10 and a idler roll 11, which may be adjustable via tensioning means 12. The run of the belt 2 is deformed, so that it intercepts the direct path of belt 1 between rolls 4 and 5, by curved guide plate 13. The curve of the guide plate 13 is the initial part of a cornu spiral and the guide plate 13 is arranged so that for material sandwiched between the lower belt 1 and the upper belt 2 the pressure exerted on the material progressively increases from substantially zero at point 14 where the material first enters between the belts 1 and 2 to a maximum at point 15 where the belts separate.
Along the run of the belt 2, between rolls 10 and 11 on the side away from the guide plate is a steering roll 16 which serves to keep the belt tracked on rolls 10 and 11. In addition, washing means 17 are provided for washing the belt 2 in the portion of its run between roll 10 and 11 to remove residues of the sludge material from the belt. The wash liquor runs into a trough 18 below the belt and is removed through a drain 19.
In operation of the apparatus, sludge to be dewatered is passed into a receiving tank 20 through an inlet orifice 21. The sludge is picked up by the lower filter belt 1 and transported to enter point 14. From point 14 the sludge is subjected to a progressively increasing pressure as the lower belt 1 is forced against the upper belt 2 by the curved guide plate 13. The liquid in the sludge passes through the lower filter belt 1 to be collected and discharged through outlet 9 and through the upper belt 2 and apertures (not shown) in the curved guide plate 13 to be discharged through outlets 21.
As is shown in Fig. 2, the guide plate 13 may be provided with a coating of a lubricious material 22, in which case, the upper filter belt 2 will pass freely over the surface of the guide plate without excessive wear.
Fig. 3 shows an alternative arrangement in which a plurality of spherical balls 23 are provided between the upper filter belt 2 and the surface of the guide plate 13. As the upper filter belt 2 is driven along the balls 23 rotate and are carried along with the belt 2.
After leaving the point 15 the balls 23 roll back along a return run surface 24 and are reintroduced between the plate 13 and the upper belt 2.
In the arrangement shown in Fig. 1, the pressed cake leaving the nip at 15 is scraped from the lower belt 1 by a scraper knife 25 and from the upper belt 2 by a scraper knife 26 and is collected at a cake discharge 27.
Should it, however, be desired to reduce the liquid content of the pressed cake still futher, the cake may be taken as a sheet from the lower filter belt 1 on passage from roll 4 and passed into a conventional multi-roll belt filter.
Claims (11)
1. Apparatus for dewatering fine fragile sludges in which the sludge while carried between a lower filter belt and an upper filter belt is subjected to a gradual and continual increase in pressure by causing the belts to follow a curved path of reducing radius.
2. Apparatus as claimed in claim 1, wherein the curved path is defined by a portion of a cornu spiral.
3. Apparatus as claimed in claim 2, wherein the curved path is defined by the beginning of a cornu spiral.
4. Apparatus as claimed in claim 2 or claim 3 wherein the cornu spiral, is generated by the " Fresnal" integrals:~
5. Apparatus as claimed in any of claims 1 to 4, wherein the belts are constrained to follow the prescribed path by bringing them into direct or indirect contact with a guide plate shaped to the desired form.
6. Apparatus as claimed in claim 5 wherein the guide plate is coated with an lubricious material and the upper filter belt is in direct contact with the guide plate.
7. Apparatus as claimed in claim 6, wherein the lubricious material is selected from graphite, molybdenum disulphide, a filled plastics material or polytetrafluorethylene.
8. Apparatus as claimed in claim 5, wherein closely packed ball or roller bearings are provided as antifraction means between the guide plate and the upper filter belt.
9. Apparatus as claimed in claim 5, wherein the guide plate is provided with a plurality of apertures passing through it to allow passage of liquid squeezed out of the sludge and passing through the filter belt.
10. Apparatus for dewatering sludge, having a first stage consisting of apparatus as claimed in any one of claims 1 to 9 and one or more subsequent stages comprising conventional multi-roll belt filter apparatus.
11. Apparatus a claimed in claim 1, substantially as described herein with reference to and as shown in the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7917277A GB2051598B (en) | 1979-05-17 | 1979-05-17 | Apparatus for dewatering sludges |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7917277A GB2051598B (en) | 1979-05-17 | 1979-05-17 | Apparatus for dewatering sludges |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2051598A true GB2051598A (en) | 1981-01-21 |
| GB2051598B GB2051598B (en) | 1983-03-16 |
Family
ID=10505240
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7917277A Expired GB2051598B (en) | 1979-05-17 | 1979-05-17 | Apparatus for dewatering sludges |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2051598B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0155658A3 (en) * | 1984-03-23 | 1987-07-29 | Alb. Klein Gmbh & Co. Kg | Double belt press |
| US4971693A (en) * | 1989-09-07 | 1990-11-20 | 501 Kabushiki Kaisha Iseki Kaihatsu Koki | Muddy water processing apparatus |
| EP0698480A1 (en) * | 1993-02-23 | 1996-02-28 | Yamamoto Kogyo Kabushiki Kaisha | Dewatering apparatus of filter belt type |
| US5656165A (en) * | 1993-02-23 | 1997-08-12 | Yamamoto Kogyo Kabushiki Kaisha | Dewatering apparatus of filter belt type |
| EP0920896A1 (en) * | 1997-12-03 | 1999-06-09 | Voith Sulzer Papiertechnik Patent GmbH | Process for dewatering a fibre suspension |
| US6561361B2 (en) * | 2001-05-01 | 2003-05-13 | Sebright Products, Inc. | Belt filter press with improved wedge section |
-
1979
- 1979-05-17 GB GB7917277A patent/GB2051598B/en not_active Expired
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0155658A3 (en) * | 1984-03-23 | 1987-07-29 | Alb. Klein Gmbh & Co. Kg | Double belt press |
| US4971693A (en) * | 1989-09-07 | 1990-11-20 | 501 Kabushiki Kaisha Iseki Kaihatsu Koki | Muddy water processing apparatus |
| AU615334B2 (en) * | 1989-09-07 | 1991-09-26 | Kabushiki Kaisha Iseki Kaihatsu Koki | Muddy water processing apparatus |
| EP0698480A1 (en) * | 1993-02-23 | 1996-02-28 | Yamamoto Kogyo Kabushiki Kaisha | Dewatering apparatus of filter belt type |
| US5656165A (en) * | 1993-02-23 | 1997-08-12 | Yamamoto Kogyo Kabushiki Kaisha | Dewatering apparatus of filter belt type |
| EP0920896A1 (en) * | 1997-12-03 | 1999-06-09 | Voith Sulzer Papiertechnik Patent GmbH | Process for dewatering a fibre suspension |
| US6143133A (en) * | 1997-12-03 | 2000-11-07 | Voith Sulzer Papiertechnik Patent Gmbh | Method and device for drainage of a fibrous suspension |
| US6561361B2 (en) * | 2001-05-01 | 2003-05-13 | Sebright Products, Inc. | Belt filter press with improved wedge section |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2051598B (en) | 1983-03-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |