CA1260848A - Apparatus for retrieving solid material from a separation medium - Google Patents
Apparatus for retrieving solid material from a separation mediumInfo
- Publication number
- CA1260848A CA1260848A CA000486022A CA486022A CA1260848A CA 1260848 A CA1260848 A CA 1260848A CA 000486022 A CA000486022 A CA 000486022A CA 486022 A CA486022 A CA 486022A CA 1260848 A CA1260848 A CA 1260848A
- Authority
- CA
- Canada
- Prior art keywords
- foam
- medium
- solid material
- reticulated
- vacuum
- 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.)
- Expired
Links
Classifications
-
- 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
- B01D33/46—Regenerating the filter material in the filter by scrapers, brushes nozzles or the like acting on the cake-side of the filtering element
- B01D33/466—Regenerating the filter material in the filter by scrapers, brushes nozzles or the like acting on the cake-side of the filtering element scrapers
-
- 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
-
- 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
- B01D33/06—Filters with filtering elements which move during the filtering operation with rotary cylindrical filtering surfaces, e.g. hollow drums
- B01D33/073—Filters with filtering elements which move during the filtering operation with rotary cylindrical filtering surfaces, e.g. hollow drums arranged for inward flow filtration
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Paper (AREA)
- Filtration Of Liquid (AREA)
Abstract
ABSTRACT
A rotating reticulated hydrophobic foam separation medium of one eighth inch thickness or greater and a por-osity in excess of forty pores per lineal inch is kept from "plugging" and maintained capable of efficient separ-ation of suspended solids from liquid over a sustained period of time by entraining the solid material from both the foam surface and the reticulated foam structure in outwardly directed fluid flows of various vacuum means.
Apparatus to create the entraining flow includes a vacuum nozzle with or without a shroud, various couch roll and vacuum combinations, and air or water nozzles to direct flows through the reticulated structure from within the rotating medium support structure.
A rotating reticulated hydrophobic foam separation medium of one eighth inch thickness or greater and a por-osity in excess of forty pores per lineal inch is kept from "plugging" and maintained capable of efficient separ-ation of suspended solids from liquid over a sustained period of time by entraining the solid material from both the foam surface and the reticulated foam structure in outwardly directed fluid flows of various vacuum means.
Apparatus to create the entraining flow includes a vacuum nozzle with or without a shroud, various couch roll and vacuum combinations, and air or water nozzles to direct flows through the reticulated structure from within the rotating medium support structure.
Description
~z~o~
BACKGROUND OF THE INV~NTION
-The use of a hydrophobic foam fllter to separa-te solid material from a stream has been described in U.S.
Patent Nos. 4,310~424 and 4,303,533. See also, U.S. Patent No. 4,212,737 whlch relies on and teaches hydrophobic foam rather than hydrophilic. In previous descriptions of the assignees' teachings, a couch roll, shower, or other mechanical means was used to retrieve the solid material from the foam surface. Such mechanical me-thods have the potential for causing compaction of the solid material within the reticulated foam structure due to the pressure exerted on the surface. The ultimate result can be a reduction in flow through the filtering medium.
BRIEF DESCRIPTION OF THE INVENTION
This invention describes methods of fiber re-trieval which minimize the build-up of solid material on the surface and within the reticulated foam structure and, therefore, maintain the volumetric ra-te through the fiber.
In accordance with the invent:ion there is pro-vided an efficient method of treating suspensions of solid material in liquid to separate a substantial portion of said solid material from said liquid which includes maximizing volumetric flow of the liquid through an open-celled reticulated hydrophobic foam separation medium and maximizing said separation for a sustained period, said method comprising: providing on a revolving drum an open-celled reticulated hydrophobic ioam separation medium of a thickness of from one-eighth inch to two inches and a porosity in the range of 40 (+10~) pores per lineal inch to ,~ - 1 -~Z608~
80 (~10~) pores per lineal inch; subjecting said foam separating medium to a lo~ gravi-ty created pressure differential by submersion of a portion thereof mounted on stream of said suspens create a flow of liquid into and through said medium, a deposit of a major part of the solid material on the sur-face of sald medium and a deposit of at least some of the rema.ining part of the solid material in the reticulated t re and the rest, includi g through the reticulated foam structure in the flow; util-i id vacuum nozzle spaced fr carrying a flexible shroud; retrieving the major portion of ' said solid material from the foam surface and from the reticulated structure by entraining solid materlal in an i ted fluid moving transver y withl within and through the open-celled reticulated hydrophobic foam medium.
The invention consists of a rotating drum, bel-t i il r device covered witb a y ~0 celled hydrophobic foam. The thickness of the foam is greater than l/8-inch and the porosity is in excess of 40 pores per lineal inch. Other characteristics of the foam - la-126(~348 are described in U.S. Patent Nos. ~,303,533 and 4,310,424.
Typically, the liquid feed stream containing suspen-ded solid material is introduced into a tank containing a rotary drum covered with an open-celled hydrophobic foam.
Regardless of the specific foam medium moving support appa-ratus, the stream is filtered as it passes through the foam, leaving some or all of the solid material on the surface, and any remainder trapped within the reticulated foam structure. The clean filtrate is withdrawn from the interior of the drum or belt structure and either reused or discarded. Any material trapped within the foam can be retrieved by expressing methods described in U.S. Patent Nos. 4,303,533 and 4,310,424.
The novel method of this invention for retrieving the ~;olid material from the foam surface and reticulated foam structure includes entraining at least some of the solitl mate!rial in a fluid passed through the foam medium.
Emodiments of the method include: ~1) vacuuming the mater-ial from the foam surface and reticulated foam structure by entrainment in a transversely directed lEluid, (2) using a couch roll to remove the majority of fiber from the foam surface and then vacuuming the surface and reticulated structure to remove the remainder of the solids, (3) using a vacuum nozzle or vacuum couch roll to remove solids from the surface anld the reticulated foam structure, (4) using a water or air~spray from inside the foam medium moving support apparatus to loosen and entrain remaining solids after first removing the major part of the solid material by means of a vacuum nozzle or couch roll.
In each case, it is important that the mechanical element, at least with regard to its rigidly fixed parts, lZ~(~89~3 be spaced so as to have only minimum contact, if any, with the foam medium. The moving and loaded foam medium inher-ently resists geometric integrity and may have areas which are variably spaced from the retrieving apparatus. If the foam medium has significant regular contact with the rigidly fixed parts of the retrieving apparatus, it will unduly abrade, distort and otherwise impair its structural integrity.
In the case of couch roll or vacuum couch roll the moving fiber mat on the foam surface provides spacing, even if there is some minimal foam compression under the roll.
In the case of a vacuum nozzle, for instance, a flexible shroud may extend from the nozzle and contact the foam to enhance entrainment.
An advantage of this invention is that the high cap-acity~ of the filter, i.e., maxiumum volumetric flow rate, can be maiotained through efficient, continuous, and thorough retrieval of solid material from the filtration surface and reticulated structure, thus minimizing any tend~ncy for build-up or "plugging" of ~;olid material which would reduce capacity.
Another advantage of the invention is that selection of various combinations of the novel retrieval methods allows the solids consistency to be tailored to meet the needs of the specific application. For example, solids can be retrieved from the foam at 1-4% consistency using vacuum only and up to 19% consistency using a couch roll/
vacuum combination in accordance with the principals of the invention.
BRIEF DESCRIPTON OF THE DRAWINGS
Figure 1 is a schematic elevational view of a drum 1~6~4~
type of foam separation device of the invention with a vacuum nozzle for retrieving the solid material Erom the foam surface and reticulated foam structure.
Figure 1a is an enlarged fragmentary view of a portion of Figure 1 showing a flexible shroud on the vacuum nozzle.
Figure 2 is a view similar to Figure 1 of a belt type of foam separation device of the invention with a couch roll followed by an air spray from inside the drum.
Figu~e 3 is a view similar to Figure 1 of a drum type of foam separation device.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
Figures 1 to 3 illustrate foam media separation devices or filters for use on a pulp or paper process stream. The devices can advantageously be utilized to recl~im and thicken fiber in streams with either occa-sion~31 or continuous high fiber loading in a manner to be described hereinafter. Like numerals identify like parts and elements in various views.
~he separation and thickening de~ice 10 of Figure 1 includes a rotary drum 12 having a thin layer of open-celled resilient hydrophobic foam 14 in a thickness range of from 1/8-inch to 2 inches (1/8" to 2n), preferably approximately 1 inch (1"), and a porosity in the range of from 40 pores per lineal inch to 80 pores per lineal inch (40 ppi to 80 ppi), preferably in the range from 65ppi to 80ppi. Other characteristics of~ the foam are as described in U.S. Patent Nos. 4,303,533 and 4,310,424.
The feed stream or pulp slurry is a aqueous solu-tion of cellulosic pulp which routinely flows from thepulpmaking or papermaking processes and which contains 84~
desirable fiber, small contaminants and small undesirable fiber parts. The feed stream is introduced into a tank 16 containing the rotary drum 12 by means of inlet pipe 18. The stream is filtered as it passes through the foam 14, leaving the majority of the larger desirable fiber 20 on the foam surface. The foam passes the marjority of the contaminants and small fiber parts with the liquid filtrate 22 which flows from the drum interior through outlet pipe 24. The difference in height between the outer liquid level in tank 16 and the inner liquid level of filtrate 22 produces a pressure differential h P-The drum type separation device of Figure 1 is pro-vided with a vacuum nozzle retrieval device 26 which removes the fiber mat or major part of the solids from the foam surface and remaining fiber particles from the reticu-lated foam structure as fluid air and residual water in the foam pass transversely through the foam and entrain the particles in their flow stream for movement outwardly toward and into the vacuum nozzle. Showers can be used subse-quently to clean the foam surface, if desired.
The vacuum nozzle retrieval device 26 deposits thesolids and residual liquid associated therewith in a sep-arator 27 connected by means of pipe 28 to blower 29 and air outlet 29a. The solids, which are typically fiber of a con-sistency of from 1-4% (1% equals 10,000 ppm) in the embodi-ment of Figure 1, is removed from separator 27 through out-let pipe 30. The blower 29 typically provides approxi-mately 8 to 12 inches (water) of vacuum at the nozzle.
In comparison with other drum filters, the separa-tion device of Figure 1 offers the following advantages:
1. Significantly higher sustained area flow rates ~2tj0~4~
of the nature of 15 to 30 gal./ft.2/min.
compared to the 10 -to 20 gal./f-t. /min.
achievable wi-th a s-tandard or typical wire or perforated plate gravity decker or vacuum thickener;
BACKGROUND OF THE INV~NTION
-The use of a hydrophobic foam fllter to separa-te solid material from a stream has been described in U.S.
Patent Nos. 4,310~424 and 4,303,533. See also, U.S. Patent No. 4,212,737 whlch relies on and teaches hydrophobic foam rather than hydrophilic. In previous descriptions of the assignees' teachings, a couch roll, shower, or other mechanical means was used to retrieve the solid material from the foam surface. Such mechanical me-thods have the potential for causing compaction of the solid material within the reticulated foam structure due to the pressure exerted on the surface. The ultimate result can be a reduction in flow through the filtering medium.
BRIEF DESCRIPTION OF THE INVENTION
This invention describes methods of fiber re-trieval which minimize the build-up of solid material on the surface and within the reticulated foam structure and, therefore, maintain the volumetric ra-te through the fiber.
In accordance with the invent:ion there is pro-vided an efficient method of treating suspensions of solid material in liquid to separate a substantial portion of said solid material from said liquid which includes maximizing volumetric flow of the liquid through an open-celled reticulated hydrophobic foam separation medium and maximizing said separation for a sustained period, said method comprising: providing on a revolving drum an open-celled reticulated hydrophobic ioam separation medium of a thickness of from one-eighth inch to two inches and a porosity in the range of 40 (+10~) pores per lineal inch to ,~ - 1 -~Z608~
80 (~10~) pores per lineal inch; subjecting said foam separating medium to a lo~ gravi-ty created pressure differential by submersion of a portion thereof mounted on stream of said suspens create a flow of liquid into and through said medium, a deposit of a major part of the solid material on the sur-face of sald medium and a deposit of at least some of the rema.ining part of the solid material in the reticulated t re and the rest, includi g through the reticulated foam structure in the flow; util-i id vacuum nozzle spaced fr carrying a flexible shroud; retrieving the major portion of ' said solid material from the foam surface and from the reticulated structure by entraining solid materlal in an i ted fluid moving transver y withl within and through the open-celled reticulated hydrophobic foam medium.
The invention consists of a rotating drum, bel-t i il r device covered witb a y ~0 celled hydrophobic foam. The thickness of the foam is greater than l/8-inch and the porosity is in excess of 40 pores per lineal inch. Other characteristics of the foam - la-126(~348 are described in U.S. Patent Nos. ~,303,533 and 4,310,424.
Typically, the liquid feed stream containing suspen-ded solid material is introduced into a tank containing a rotary drum covered with an open-celled hydrophobic foam.
Regardless of the specific foam medium moving support appa-ratus, the stream is filtered as it passes through the foam, leaving some or all of the solid material on the surface, and any remainder trapped within the reticulated foam structure. The clean filtrate is withdrawn from the interior of the drum or belt structure and either reused or discarded. Any material trapped within the foam can be retrieved by expressing methods described in U.S. Patent Nos. 4,303,533 and 4,310,424.
The novel method of this invention for retrieving the ~;olid material from the foam surface and reticulated foam structure includes entraining at least some of the solitl mate!rial in a fluid passed through the foam medium.
Emodiments of the method include: ~1) vacuuming the mater-ial from the foam surface and reticulated foam structure by entrainment in a transversely directed lEluid, (2) using a couch roll to remove the majority of fiber from the foam surface and then vacuuming the surface and reticulated structure to remove the remainder of the solids, (3) using a vacuum nozzle or vacuum couch roll to remove solids from the surface anld the reticulated foam structure, (4) using a water or air~spray from inside the foam medium moving support apparatus to loosen and entrain remaining solids after first removing the major part of the solid material by means of a vacuum nozzle or couch roll.
In each case, it is important that the mechanical element, at least with regard to its rigidly fixed parts, lZ~(~89~3 be spaced so as to have only minimum contact, if any, with the foam medium. The moving and loaded foam medium inher-ently resists geometric integrity and may have areas which are variably spaced from the retrieving apparatus. If the foam medium has significant regular contact with the rigidly fixed parts of the retrieving apparatus, it will unduly abrade, distort and otherwise impair its structural integrity.
In the case of couch roll or vacuum couch roll the moving fiber mat on the foam surface provides spacing, even if there is some minimal foam compression under the roll.
In the case of a vacuum nozzle, for instance, a flexible shroud may extend from the nozzle and contact the foam to enhance entrainment.
An advantage of this invention is that the high cap-acity~ of the filter, i.e., maxiumum volumetric flow rate, can be maiotained through efficient, continuous, and thorough retrieval of solid material from the filtration surface and reticulated structure, thus minimizing any tend~ncy for build-up or "plugging" of ~;olid material which would reduce capacity.
Another advantage of the invention is that selection of various combinations of the novel retrieval methods allows the solids consistency to be tailored to meet the needs of the specific application. For example, solids can be retrieved from the foam at 1-4% consistency using vacuum only and up to 19% consistency using a couch roll/
vacuum combination in accordance with the principals of the invention.
BRIEF DESCRIPTON OF THE DRAWINGS
Figure 1 is a schematic elevational view of a drum 1~6~4~
type of foam separation device of the invention with a vacuum nozzle for retrieving the solid material Erom the foam surface and reticulated foam structure.
Figure 1a is an enlarged fragmentary view of a portion of Figure 1 showing a flexible shroud on the vacuum nozzle.
Figure 2 is a view similar to Figure 1 of a belt type of foam separation device of the invention with a couch roll followed by an air spray from inside the drum.
Figu~e 3 is a view similar to Figure 1 of a drum type of foam separation device.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
Figures 1 to 3 illustrate foam media separation devices or filters for use on a pulp or paper process stream. The devices can advantageously be utilized to recl~im and thicken fiber in streams with either occa-sion~31 or continuous high fiber loading in a manner to be described hereinafter. Like numerals identify like parts and elements in various views.
~he separation and thickening de~ice 10 of Figure 1 includes a rotary drum 12 having a thin layer of open-celled resilient hydrophobic foam 14 in a thickness range of from 1/8-inch to 2 inches (1/8" to 2n), preferably approximately 1 inch (1"), and a porosity in the range of from 40 pores per lineal inch to 80 pores per lineal inch (40 ppi to 80 ppi), preferably in the range from 65ppi to 80ppi. Other characteristics of~ the foam are as described in U.S. Patent Nos. 4,303,533 and 4,310,424.
The feed stream or pulp slurry is a aqueous solu-tion of cellulosic pulp which routinely flows from thepulpmaking or papermaking processes and which contains 84~
desirable fiber, small contaminants and small undesirable fiber parts. The feed stream is introduced into a tank 16 containing the rotary drum 12 by means of inlet pipe 18. The stream is filtered as it passes through the foam 14, leaving the majority of the larger desirable fiber 20 on the foam surface. The foam passes the marjority of the contaminants and small fiber parts with the liquid filtrate 22 which flows from the drum interior through outlet pipe 24. The difference in height between the outer liquid level in tank 16 and the inner liquid level of filtrate 22 produces a pressure differential h P-The drum type separation device of Figure 1 is pro-vided with a vacuum nozzle retrieval device 26 which removes the fiber mat or major part of the solids from the foam surface and remaining fiber particles from the reticu-lated foam structure as fluid air and residual water in the foam pass transversely through the foam and entrain the particles in their flow stream for movement outwardly toward and into the vacuum nozzle. Showers can be used subse-quently to clean the foam surface, if desired.
The vacuum nozzle retrieval device 26 deposits thesolids and residual liquid associated therewith in a sep-arator 27 connected by means of pipe 28 to blower 29 and air outlet 29a. The solids, which are typically fiber of a con-sistency of from 1-4% (1% equals 10,000 ppm) in the embodi-ment of Figure 1, is removed from separator 27 through out-let pipe 30. The blower 29 typically provides approxi-mately 8 to 12 inches (water) of vacuum at the nozzle.
In comparison with other drum filters, the separa-tion device of Figure 1 offers the following advantages:
1. Significantly higher sustained area flow rates ~2tj0~4~
of the nature of 15 to 30 gal./ft.2/min.
compared to the 10 -to 20 gal./f-t. /min.
achievable wi-th a s-tandard or typical wire or perforated plate gravity decker or vacuum thickener;
2. The potential for sustained fiber consistencies of the nature of 12 to 19 percent compared to 12 percent maximum obtained with typical wire or perforated plate deckers or thickeners, when multiple retrieving devices are used.
The inherent resistance flow of the typical thickener wire is higher than that of the foam within the . ~
disclosed porosity and thickness ranges, and these ranges due to their porosity and their vold volume provide incr~ased fluid takeaway and driving force -throughout the proce!ss over that obtained in wire covered thickeners. The prese~nt invention permits this flow to be sustained.
Figure la illustrates a portion of the Figure 1 apparatus with the attachment oE a flexible shroud 26a attached to the rigid vacuum nozzle. This prevents the rigid nozzle structure from damaging contact with the foam but permits an enhanced vacuum entrainment by minimizing extraneous fluid flow and directing the major fluid flow transversely through the foam. The flexible shroud 26a does little, If any, damage to the foam.
:.
:~' ' ' .
~Z~ 4l3 Figure 2 illus-trates a foam bel-t filter device 110 which utilizes a foam separation medium 114 having -the proper porosity and thickness. The foam medium 114 rota-tionally driven about rotating members 112a and 112b. The schematic drawing of device 110 shows that a feed - 6a -~, ~
~ .
~60~
stream tank 116 deposits a feed stream on foam belt 114 and a vacuum draws filtrate 122 into a reservoir 223 for removal through outlet pipe 124. The fiber mat 120 is retrieved by a doctor 226 from the surface of a couch roll 125. Vacuum nozzle 128 is provided to clean the foam belt surface and reticulated structure after retrieval.
Separator 127, air outlet 128a and outlet pipe 130 for the fiber complete the illustrated combination. A blower tnot shown) is connected as shown in Figure 1 to provide the vacuum at nozzle 128.
Figure 3 illustrates an apparatus 210 similar to the Figùre 1, apparatus 10, with tank 216, drum 212 and Eoam 214. The apparatus 210 includes a vacuum couch roll 226 from which the doctor 226a removes the fiber for a gravity drop onto chute 231 and into tank 232 with fiber outlet pipe 230. A fluid nozzle 240 directs a fluid, which is air, water or both, transversely through the rotating foam medium 214 to entrain the solids on the surface and in the reticulated structure not picked up by the vacuum couch roll 226 and to deposit them on chute 231.
By use of the retrieval apparatus of the embodiments of the invention, the advantages of foam filtration can be obtained for substantial periods of time with minimal loading or "plugging" of the reticulate structure of the foam.
A typical foam filtration test run on an alkaline bleach sewer, ~sing a vacuum nozzle apparatus of the type illustrated in Figure 1, with one inch 65 ppi stiff foam, on a drum turning 2.5 RPM, produced the following data:
~2608~
Elapsed time: 47 hours (foam use) Flow (rate in): 63 GPM (gal./min.) Flow (rate through): 27.9 GFM (effective area yal./ft.
2/min. ) 5 Vacuum: 8 in. (water ~ P) Stream: TSS ASH TS T PH
(PPM) (%) (PPM) (F.) Feed: 294 14 5,092 116 9.6 Filtrate: 80 40 4,812 116 9.6 Fiber: 15,558 2 19,636 116 9.6 Legend: TSS = total suspended solids TS - total solids T ~= temperature (F.) Running the foam filtration apparatus with couch roll retrieval only can obtain fiber consistency up to 19%
but this cannot be sustained easily without the use of vacuum or other fluid entrainment to remove material from the reticulated foam structure and thereby prevent loading or "plugging."
Another test run on paper machine white water using a vacuum nozzle similar to the apparatus of Figure 1 as a "saveall," with 1" 80ppi stiff foam and a drum turning at
The inherent resistance flow of the typical thickener wire is higher than that of the foam within the . ~
disclosed porosity and thickness ranges, and these ranges due to their porosity and their vold volume provide incr~ased fluid takeaway and driving force -throughout the proce!ss over that obtained in wire covered thickeners. The prese~nt invention permits this flow to be sustained.
Figure la illustrates a portion of the Figure 1 apparatus with the attachment oE a flexible shroud 26a attached to the rigid vacuum nozzle. This prevents the rigid nozzle structure from damaging contact with the foam but permits an enhanced vacuum entrainment by minimizing extraneous fluid flow and directing the major fluid flow transversely through the foam. The flexible shroud 26a does little, If any, damage to the foam.
:.
:~' ' ' .
~Z~ 4l3 Figure 2 illus-trates a foam bel-t filter device 110 which utilizes a foam separation medium 114 having -the proper porosity and thickness. The foam medium 114 rota-tionally driven about rotating members 112a and 112b. The schematic drawing of device 110 shows that a feed - 6a -~, ~
~ .
~60~
stream tank 116 deposits a feed stream on foam belt 114 and a vacuum draws filtrate 122 into a reservoir 223 for removal through outlet pipe 124. The fiber mat 120 is retrieved by a doctor 226 from the surface of a couch roll 125. Vacuum nozzle 128 is provided to clean the foam belt surface and reticulated structure after retrieval.
Separator 127, air outlet 128a and outlet pipe 130 for the fiber complete the illustrated combination. A blower tnot shown) is connected as shown in Figure 1 to provide the vacuum at nozzle 128.
Figure 3 illustrates an apparatus 210 similar to the Figùre 1, apparatus 10, with tank 216, drum 212 and Eoam 214. The apparatus 210 includes a vacuum couch roll 226 from which the doctor 226a removes the fiber for a gravity drop onto chute 231 and into tank 232 with fiber outlet pipe 230. A fluid nozzle 240 directs a fluid, which is air, water or both, transversely through the rotating foam medium 214 to entrain the solids on the surface and in the reticulated structure not picked up by the vacuum couch roll 226 and to deposit them on chute 231.
By use of the retrieval apparatus of the embodiments of the invention, the advantages of foam filtration can be obtained for substantial periods of time with minimal loading or "plugging" of the reticulate structure of the foam.
A typical foam filtration test run on an alkaline bleach sewer, ~sing a vacuum nozzle apparatus of the type illustrated in Figure 1, with one inch 65 ppi stiff foam, on a drum turning 2.5 RPM, produced the following data:
~2608~
Elapsed time: 47 hours (foam use) Flow (rate in): 63 GPM (gal./min.) Flow (rate through): 27.9 GFM (effective area yal./ft.
2/min. ) 5 Vacuum: 8 in. (water ~ P) Stream: TSS ASH TS T PH
(PPM) (%) (PPM) (F.) Feed: 294 14 5,092 116 9.6 Filtrate: 80 40 4,812 116 9.6 Fiber: 15,558 2 19,636 116 9.6 Legend: TSS = total suspended solids TS - total solids T ~= temperature (F.) Running the foam filtration apparatus with couch roll retrieval only can obtain fiber consistency up to 19%
but this cannot be sustained easily without the use of vacuum or other fluid entrainment to remove material from the reticulated foam structure and thereby prevent loading or "plugging."
Another test run on paper machine white water using a vacuum nozzle similar to the apparatus of Figure 1 as a "saveall," with 1" 80ppi stiff foam and a drum turning at
3.5 RPM, produced the following data.
Elapsed time: 43 hours (foam use) Flow (rate in): 87 GPM (gal./min.) 2 Flow (rate through): 2.8 GFM (effective area gal./ft. /
min.) Va,cuum: 6 in. (water ~ P) Stream: TSS ASH TS T PH
(PPM) (~) ~PPM) (F.) Feed: 3,353 23 4,670 100 5.8 Filtrate: 27 29 1,369 100 5.8 Fiber: 38,084 20 39,950 --- 6.0 . ' ",'~ ~ ' 12~0848 This was the highest fiber recovery of the tests using only a vacuum nozzle and approached 4~. The fiber at this consistency can be directly recycled to the paper machine system. Obviously, the couch roll and vacuum combination would be the most effective way to retrieve and thicken fiber from the foam medium up to 19%
consistency for storage or disposal.
A more typical run as a "saveall" using the same white water feed stream and foam medium, with the drum turning at 2.0 RPM, produced the following data~
Elapsled time: 24 hours (foam use) Flow ~rate in): 178 GPM (gal./min.) Flow ~rate through): 6.0 GFM (effective area gal./ft.2/
min.) Vacuum: 8 in. (water ~ P) Stream: TSS ASH TS T PH
(PPM) (%) (PPM) (F.) Feed: 2,594 15 3,574 82 5.3 Filtrate: 67 63 1,537 82 5.4 Fiber: 24,912 13 26,37~ 81 5.1 Recovery of suspended solids from pulp mill process streams using the foam filter fiber retrieval apparatus of the invention can be sustained rnany hours. This is sig-nificant because these systems typically handle between 6.5 and 20.5 tons of fiber per day. Analysis of the recov-ered fiber, including freeness, viscosity, permanganate number, and fis)er length, shows they are all typically in the normal range for desirable asld useable fiber.
Elapsed time: 43 hours (foam use) Flow (rate in): 87 GPM (gal./min.) 2 Flow (rate through): 2.8 GFM (effective area gal./ft. /
min.) Va,cuum: 6 in. (water ~ P) Stream: TSS ASH TS T PH
(PPM) (~) ~PPM) (F.) Feed: 3,353 23 4,670 100 5.8 Filtrate: 27 29 1,369 100 5.8 Fiber: 38,084 20 39,950 --- 6.0 . ' ",'~ ~ ' 12~0848 This was the highest fiber recovery of the tests using only a vacuum nozzle and approached 4~. The fiber at this consistency can be directly recycled to the paper machine system. Obviously, the couch roll and vacuum combination would be the most effective way to retrieve and thicken fiber from the foam medium up to 19%
consistency for storage or disposal.
A more typical run as a "saveall" using the same white water feed stream and foam medium, with the drum turning at 2.0 RPM, produced the following data~
Elapsled time: 24 hours (foam use) Flow ~rate in): 178 GPM (gal./min.) Flow ~rate through): 6.0 GFM (effective area gal./ft.2/
min.) Vacuum: 8 in. (water ~ P) Stream: TSS ASH TS T PH
(PPM) (%) (PPM) (F.) Feed: 2,594 15 3,574 82 5.3 Filtrate: 67 63 1,537 82 5.4 Fiber: 24,912 13 26,37~ 81 5.1 Recovery of suspended solids from pulp mill process streams using the foam filter fiber retrieval apparatus of the invention can be sustained rnany hours. This is sig-nificant because these systems typically handle between 6.5 and 20.5 tons of fiber per day. Analysis of the recov-ered fiber, including freeness, viscosity, permanganate number, and fis)er length, shows they are all typically in the normal range for desirable asld useable fiber.
Claims (2)
1. An efficient method of treating suspension of solid material in liquid to separate a substantial portion of said solid material from said liquid which includes maximizing volumetric flow of the liquid through an open-celled reticulated hydrophobic foam separation medium and maximizing said separation for a sustained period, said method comprising:
providing on a revolving drum an open-celled reticulated hydrophobic foam separation medium of a thickness of from one-eighth inch to two inches and a porosity in the range of 40 (+10%) pores per lineal inch to 80 (?10%) pores per lineal inch;
subjecting said foam separating medium to a low gravity created pressure differential by submersion of a portion thereof mounted on said drum and to a stream of said suspension thereby to create a flow of liquid in-to and through said medium, a deposit of a major part of the solid material on the surface of said medium and a deposit of at least some of the remaining part of the solid material in the reticulated foam structure and the rest, including most contaminants, through the reticulated foam structure in the flow;
utilizing a rigid vacuum nozzle spaced from said medium and carrying a flexible shroud;
retrieving the major portion of said solid material from the foam surface and from the reticulated structure by entraining solid material in an outwardly directed fluid moving transversely in contact with, within and through the open-celled reticulated hydrophobic foam medium.
providing on a revolving drum an open-celled reticulated hydrophobic foam separation medium of a thickness of from one-eighth inch to two inches and a porosity in the range of 40 (+10%) pores per lineal inch to 80 (?10%) pores per lineal inch;
subjecting said foam separating medium to a low gravity created pressure differential by submersion of a portion thereof mounted on said drum and to a stream of said suspension thereby to create a flow of liquid in-to and through said medium, a deposit of a major part of the solid material on the surface of said medium and a deposit of at least some of the remaining part of the solid material in the reticulated foam structure and the rest, including most contaminants, through the reticulated foam structure in the flow;
utilizing a rigid vacuum nozzle spaced from said medium and carrying a flexible shroud;
retrieving the major portion of said solid material from the foam surface and from the reticulated structure by entraining solid material in an outwardly directed fluid moving transversely in contact with, within and through the open-celled reticulated hydrophobic foam medium.
2. The method of claim 1 in which the fluid is provided from within a rotating structure supporting the foam medium.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US63459484A | 1984-07-26 | 1984-07-26 | |
| US634,594 | 1984-07-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1260848A true CA1260848A (en) | 1989-09-26 |
Family
ID=24544444
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000486022A Expired CA1260848A (en) | 1984-07-26 | 1985-06-28 | Apparatus for retrieving solid material from a separation medium |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS6138609A (en) |
| CA (1) | CA1260848A (en) |
| DE (1) | DE3523998A1 (en) |
| FR (1) | FR2568140B1 (en) |
| GB (1) | GB2162080B (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4225818C2 (en) * | 1991-09-11 | 1993-12-09 | Geldmacher Joachim | Filters for the continuous filtering of solids or similar liquids |
| DE59604048D1 (en) * | 1995-03-24 | 2000-02-03 | Ulrich I Steinike | HIKING CLEANER |
| DE29505007U1 (en) * | 1995-03-24 | 1996-08-01 | Steinike Ulrich I | Filter cleaning device |
| DE102005002844A1 (en) * | 2005-01-20 | 2006-07-27 | Knoll Maschinenbau Gmbh | Cleaning device for filter belts |
| JP5033734B2 (en) * | 2008-08-05 | 2012-09-26 | 鹿島建設株式会社 | Magnetic body recovery device and jet stirring system using the same |
| SE535158C2 (en) * | 2010-08-30 | 2012-05-02 | Veolia Water Solutions & Tech | Movable filter blower for filters |
| US11529573B2 (en) | 2019-04-23 | 2022-12-20 | Greatpyr Resources Llc | Systems and processes employing wet/dry suction filter |
| CN110142261B (en) * | 2019-05-07 | 2021-05-04 | 杭州大橙知一科技有限公司 | Full-automatic rubber tube inner wall cleaning device |
| GB2605944A (en) * | 2021-03-12 | 2022-10-26 | Greatpyr Resources Llc | Systems and processes employing wet/dry suction filter |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE481983C (en) * | 1929-09-06 | Alfred Scholz | Removal device for vacuum rotary filter | |
| DE240978C (en) * | ||||
| DE612648C (en) * | 1931-01-07 | 1935-04-30 | Dorr Oliver Ges M B H | Suction chamber for removing the filter cake from a rotary drum filter |
| GB682462A (en) * | 1948-10-01 | 1952-11-12 | Weinhold Karl | Improvements in and relating to filters |
| GB867690A (en) * | 1958-06-26 | 1961-05-10 | Gen Engineering Company Ab | Improved filtering apparatus |
| GB1184066A (en) * | 1966-06-07 | 1970-03-11 | Euroflow Systems Ltd | Improvements in or relating to Filter Apparatus |
| DE1954909A1 (en) * | 1968-11-04 | 1970-05-14 | Gen American Transp Corp | Method and device for dewatering sludge |
| NL7110689A (en) * | 1971-05-17 | 1972-11-21 | ||
| FR2381721A1 (en) * | 1977-02-25 | 1978-09-22 | Jacques Robert | Moving filter belt for waste water - with suction head to remove particles jammed in the meshes |
| DE2712414A1 (en) * | 1977-03-22 | 1978-09-28 | Basf Ag | METHODS AND DEVICES FOR THE REMOVAL OF PARTICULARS FROM SUSPENSIONS BY FILTRATION THROUGH FOAMS |
| US4303533A (en) * | 1980-05-30 | 1981-12-01 | Champion International Corporation | Method of removing fine suspended solids from effluent streams |
| US4310424A (en) * | 1980-07-23 | 1982-01-12 | Champion International Corporation | Apparatus and method for removing suspended solids from a stream |
| DE3047539A1 (en) * | 1980-12-17 | 1982-07-22 | Klöckner-Humboldt-Deutz AG, 5000 Köln | Vacuum drum filter - with internal blow-off shoes for lifting off filter cake and removing remnants from filter cloth |
| DE3482411D1 (en) * | 1983-12-23 | 1990-07-12 | Champion Int Corp | FIBER DETECTION FROM A WATER FLOW. |
-
1985
- 1985-06-27 GB GB08516246A patent/GB2162080B/en not_active Expired
- 1985-06-28 CA CA000486022A patent/CA1260848A/en not_active Expired
- 1985-07-04 DE DE19853523998 patent/DE3523998A1/en active Granted
- 1985-07-25 FR FR858511402A patent/FR2568140B1/en not_active Expired - Lifetime
- 1985-07-25 JP JP16311085A patent/JPS6138609A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| FR2568140B1 (en) | 1990-03-23 |
| GB2162080B (en) | 1988-01-06 |
| DE3523998A1 (en) | 1986-01-30 |
| GB8516246D0 (en) | 1985-07-31 |
| JPS6138609A (en) | 1986-02-24 |
| FR2568140A1 (en) | 1986-01-31 |
| GB2162080A (en) | 1986-01-29 |
| DE3523998C2 (en) | 1992-07-09 |
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