CA1092405A - Dual belt pulp washer - Google Patents
Dual belt pulp washerInfo
- Publication number
- CA1092405A CA1092405A CA316,488A CA316488A CA1092405A CA 1092405 A CA1092405 A CA 1092405A CA 316488 A CA316488 A CA 316488A CA 1092405 A CA1092405 A CA 1092405A
- Authority
- CA
- Canada
- Prior art keywords
- wash
- drums
- liquid
- belts
- drum
- 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
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06B—TREATING TEXTILE MATERIALS USING LIQUIDS, GASES OR VAPOURS
- D06B3/00—Passing of textile materials through liquids, gases or vapours to effect treatment, e.g. washing, dyeing, bleaching, sizing, impregnating
- D06B3/02—Passing of textile materials through liquids, gases or vapours to effect treatment, e.g. washing, dyeing, bleaching, sizing, impregnating of fibres, slivers or rovings
Abstract
DUAL BELT PULP WASHER
ABSTRACT OF THE INVENTION
A machine and process for washing paper stock pulp and similar free-filtering materials includes two or more horizontally-disposed wash drums (11) mounted each in a tank (45). Two endless filter belts (83 and 85) are trained to pass under each of said wash drums (11) and through liquid contained in each of the tanks (45).
A mat of pulp (102) is formed between the two endless filter belts (83 and 85) and carried under each of the wash drums (11) for washing therein. Wash liquor passes through the pulp mat (102) as it travels under each of the drums (11) thereby washing the pulp mat, and the liquor passes between the drums (11) and the tanks (45 and 47) by gravity flow. After the pulp has been washed it is removed from between the two belts (83 and 85).
ABSTRACT OF THE INVENTION
A machine and process for washing paper stock pulp and similar free-filtering materials includes two or more horizontally-disposed wash drums (11) mounted each in a tank (45). Two endless filter belts (83 and 85) are trained to pass under each of said wash drums (11) and through liquid contained in each of the tanks (45).
A mat of pulp (102) is formed between the two endless filter belts (83 and 85) and carried under each of the wash drums (11) for washing therein. Wash liquor passes through the pulp mat (102) as it travels under each of the drums (11) thereby washing the pulp mat, and the liquor passes between the drums (11) and the tanks (45 and 47) by gravity flow. After the pulp has been washed it is removed from between the two belts (83 and 85).
Description
DUAL BELT PULP WASHER
¦ BACKGROUND OF THE INVENTION
.
' Field of the Invention . _ - The present invention relates to machines for washing paper stock pulp and other free-filtering ! 5 materials.
.
State of the Art , According to various processes well-known in the -~ paper making industry, paper stock pulp is formed by - digesting wood chips in the presence of various ¦ 10 chemicals in a heated -¦ pressure vessel. After discharge from the `1 pressure vessel, the paper stock pulp must be washed --~, - and filtered to separate the wood fibers from the - digestion chemicals.
According to a conventional system for washing paper stock pulp the pulp is diluted with water after digestion and then is picked up by a large-diameter . rotating cylinder whose surface is formed of a wire mesh screen. A couch roll is positioned to press downward onto the.surface of the screen-covered ; cylinder to express liquid from the stock and thus to ~- form a blanket or mat of dewatered fibers. Such a conventional system further includes an agitation device wherein once-dewatered fibers are repulped by mixing with water. Still further, the system includes additional agitation devices, screen-covered cylinders, and couch rolls to wash the pulp in stages.
-:~
, , 1~92405 I According to other processes well-known in the paper-making industry, materials such as waste paper and ground-wood, although not digested with chemicals, must nevertheless be washed. Conventional systems for such washing are also known.
! ` `- According to still other processes well-known in the papermaking industry paper pulp is bleached by treating the pulp with chemicals such as a solution of chlorine or sodium hydroxide. In other processes chemical solutions are often used to treat the pulp.
.
OBJECTS OF THE INVENTION
The primary object of the present invention is to i provide an improved machine to wash paper stock pulp ¦ and other free-filtering materials. As will be readily understood in view of the following description, the term free-filtering encompasses materials which, ~hen ' covering a filtering surface, allow liquid to pass -l readily there through when a slight hydraulic head is exerted. The term pulp is used herein as a synonym for ` 20 free-filtering materials.
Another object of the present invention is to ~ provide an improved machine for treating pulp with ¦ solutions of chemicals to accomplish bleaching and - other processes. The term "washing" is used herein to include such treatment with chemical solutions, and the term "liquid" includes such chemical solutions.
A more specific object of the present invention is to provide an improved machine for washing pulp, which machine is of the type which operates without interstage pumps.
Yet another object of the present invention is to ~, provide an improved machine for washing pulp which operates without re-pulping of the pulp stock.
;~
~.
- io~240s Still another object of the present invention is i to provide a machine for washing pulp wherein frothing ! of the pulp is substantially minimized.
¦ BRIEF DESCRIPTION OF THE DRAWINGS
j 5 The above and other objects of the present I ` invention may be readily ascertained by consideration ¦ of the following detailed description and appended ! drawings, which are offered by way of illustration only , and not in limitation of the invention, the scope of ¦ 10 which is defined by the appended claims and equivalents.
In the drawings:
i Figure 1 is a side elevation of a machine - according to the present invention shown schematically;
Figure 2 is a view taken along line 2-2 in Figure .' 1 ~! for viewing in the direction of the arrows which ' schematically illustrates one detail of the machine of j Figure 1 partially cut away;
Figure 3 shows a detail of the machine of Figure 1 , enlarged for purposes of clarity;
j Figure 4 is a side elevation of another embodiment i of a machine according to the present invention.
¦ Figure 5 is a view taken along line 5-5 in Figure j 25 4 which schematically shows a detail of the machine of ! `~ Figure 1 partially cut away.
! Figure 6 shows a detail of the machine of Figure 4.
i DETAILED DESCRIPTION OF THE INVENTION
As shown in Figure 1, a machine according to this invention generally includes horizontally-disposed wash drums 11 and 13 which are mounted in spaced-apart, side-by-side relationship. The wash drums are illustrated as being cylinders of equal diameter but, in certain instances, it may be desirable for the wash drums to have different diameters. The wash drums are mounted in vertically stepped relationship to one another so that the central axis of the first drum 11 is lower than the central axis of the second drum 13.
The two illustrated drums are essentially the same in construction and operation and, for that reason, only one wash drum 11 will now be described in detail.
- 15 With reference now to Figures 1 and 2, the wash drum 11 includes a cylindrical sidewall 19 and end closure walls 21 and 23. The cylindrical sidewall is perforated say by small spaced-apart apertures 25 to .
permit liquid to flow freely from the drum. Workers skilled in this art will readily recognize that the side~walls of the drums, instead of being peFforated, could be comprised of a wedgewire grid or other conventional support means which permit liquid flow.
The end closure walls 21 and 23 are nonforaminate.
Axle members 27 and 29 are fixed to the end closure ! ~ walls 21 and 23, respectively, and are supported for rotation outboard of the drum by stationary pillow ' blocks 33 and 35, respectively, or other journal means.
According to the embodiment in Figure 2, a tube 39 is stationarily mounted to extend into the wash drum 11 to introduce liquid into its interior. The illustrated tube 39 has a horizontal section 40 which extends into the drum through the axle member 27, and a leg 42 which extends downward inside the drum.
109Z4~)5 With respect to the machine in Figure 1, tubes 39 and 43 are mounted in communication with the interiors of wash drums 11 and 13 respectively. Tube 43 should be understood to be the same in construction and S operation as the tube 39 described above.
' Referring still to Figure 1, open tanks 45 and 47 are mounted below the respective wash drums 11 and 13.
The tanks are constructed and positioned to encompass the lower half or less of each of the respective wash drums and to contain a substantial quantity of liquid exterior of the wash drums. In practice, the tanks preferably are identical to one another and are mounted in vertically-stepped relationship corresponding to the differential elevations of the wash drums. A plate 49 is connected between the upper-edges of tanks 45 and 47, and a second plate 50 is connected to the upper edge of tank 47 to extend upward therefrom.
A liquid inlet means, such as a conduit 51 shown in Figure 1, is connected in communication with the tube 43 to carry wash liquor into the wash drum 13. In - some applications, the wash liquor may simply be fresh water while in other instances it may be an aqueous solution of particular chemicals or a non-aqueous liquid. As will be understood in view of the following description, the flow of wash liquid is countercurrent to the direction of travel of pulp material through the machine.
I Referring now to Figures 1 and 3, a compression roller member 55 is mounted to the right and above the first wash drum and is supported for rotation by conventional means, not shown. The compression roller member 55 shown in Figure 3 comprises, for example, a rigid hollow cylinder which is formed from wire screen or other foraminous material so that liquid can drain freely through it. Likewise, a second compression :`
.
roller member 57 is rotatably mounted to the right and j above the second wash drum 13. The second roller ¦ member 57 is mounted adjacent the second drum 13 and can be adjustably positioned relative to the second drum. The second roller member 57 is the same in I construction as roller member 55. However, the second j roller member 57 can optio~ally have a rigid, non-foraminate wall.
As further-shown in Figure 1, a conduit 69 is coupled to the tank 47 to carry liquid therefrom to tube 39. A conduit 71 is connected to tank 45 to carry liquid therefrom to disposal.
The machine in Figure 1 further includes feed means which, in the illustrated embodiment by way of example, comprises a horizontal vacuum pan 75 of conventional construction which is mounted to the left of the first wash drum 11. A conventional suction-producing device, not shown, is connected in communication with the interior of the vacuum pan to draw liquid therefrom via a conduit 76. Above the vacuum pan 75 is mounted a distribution box 77, which also is of conventional construction. At the opposite ends of the vacuum pan are rotatably mounted support rollers 79 and 81, respectively. One skilled in this art should readily recognize that the feed means could, alternatively, comprise other conventional means for forming a pulp mat between two belts. For example, the feed means could comprise a conventional vacuum drum means or a conventional system including two belts disposed substantially vertically.
Two endless filter belts 83 and 85, referred to herein as the upper and lower belts respectively, are trained around the wash drums and the compression roller members in zig-zag fashion as illustrated in .
1~)9Z405 Figure l. More particularly, the endless belts are i trained in face-to-face relationship to each other to pass under each of the wash drums 11 and 13 and over each of the compression roller members 55 and 57. The 5 endless belts should be understood to comprise conventional porous filter belts of the type which are well known in the filtration art.
Above the machine, the upper belt 83 is trained over a set of guide rollers 90-94; below the machine, the lower belt 85 is trained over a set of guide -! rollers 95-lO0. Conventional drive means, not shown, , are connected to rotatably drive the roller member 57 and, thus, to cause the two endless belts 83 and 85 to - travel together at equal speeds in the directions indicated by the arrows in Figure 1. The upper and lower sets of guide rollers are positioned to separate the upper and lower belts after the belts have passed over the second compression roller member 57 and, at the opposite end of the machine, to reunite the belts in face-to-face relationship before the belts travel under the first wash drum ll. It should be further ., observed that the lower set of guide rollers 95-100 is positioned so that the lower belt 85 passes around the - support roller 79, then between the vacuum pan 75 and the distribution box 77, and finally over the support roller 81 before reuniting with the upper belt 83. In practice, at least one guide roller in both the upper and lower sets is movably mounted so that the tensions of the belts can be selectively adjusted. Also, ! 30 conventional means for laterally aligning the belts are normally provided.
The operation o the above-described machine can now be understood. Initially a free-filtering material, such as paper stock pulp containing digestion , .
; chemicals, is fed into the distribution box 77 as I indicated by the arrow. That material is then ¦ discharged onto the belt 85 as it travels across the vacuum pan 75. Suction applied through the vacuum pan 75 draws liquid from the pulp, leaving a sheet or mat 102 of partially dewatered fibers lying on the belt 85.
The withdrawn liquid, or filtrate, is discharged from ! the machine via conduit 76. The lower belt 85, after passage across the vacuum pan, meets the upper belt 83 in face-to-face relationship and, thus, the mat of pulp fibers is gripped between the two belts.
Typically, the pulp mat is about one-quarter to one j inch in thickness.
j The two belts 83 and 85, with the pulp mat between j 15 them, then pass into the first tank 45 and under the - first wash drum 11. Simultaneously the wash drum 11 is --rotated, say by frictional engagement with the upper belt 83. At this time, liquid from inside the first drum 11 passes through the pulp mat between the two , - 20 belts and then flows into the tank 45. This flow of liquid through the pulp mat occurs because of the differential in the hydrostatic head (liquid level) between the interior and exterior of the wash drum 11.
The flow of liquid through the pulp mat serves to wash the pulp and, in some instances, also increases the moisture content of the pulp mat because some of the ~ wash liquid is absorbed by the pulp.
¦ The two belts 83 and 85, after passing under the wash drum 11J then pass over the first compression roller member 55. During this stage, the pulp mat is squeezed between the belts due to the tension in the upper belt 83. Liquid, which is thus expressed from -1~)92405 the pulp, drains through the roller member 55 as shown in Figure 3. The expressed liquor is caught by the plate 49 and flows into the tank 45.
After passage over the first compression roller member 55, the two endless belts 83 and 85 carry the pulp mat into the second tank 47 and then under the second wash drum 13. During this stage, the pulp mat undergoes a second wash like the one described above.
Then, the two belts 83 and 85 with the pulp mat therebetween pass over the second compression roller member 57. Thus it can be seen that the pulp mat ~i undergoes two stages of washing and expression. The ¦ second compression roller 57 is positioned relative to the drum 13 so that the two belts are simultaneously ; 15 tangent to both the drum and the roller. The position of the roller 57 is adjusted to compress the pulp mat and express liquid therefrom.
After pressing over the roller 57 the upper and lower belts 83 and 85 are moved apart by the guide rollers 94 and 95 to expose the washed pulp mat. The pulp mat is then discharged from the machine by suitable means, not shown, such as a doctor blade or the like.
As mentioned earlier, the upper and lower belts are held under predetermined tensions by the adjustable I - guide rollers. The tensions need not be the same. In fact, the upper belt 83 is preferably at greater ! tension than the lower belt 85. This causes the compressive force on the pulp mat to be greater when the mat passes over the compression rollers 55 and 57 than when it passes under the wash drums 11 and 13.
This is advantageous because the pulp mat is "worked", i.e., compressed during its passage over the compression roller members and allowed to expand and absorb wash liquid when passing under the wash drums.
!
This working can be likened to wringing a sponge and then allowing it to expand to absorb more water.
At this juncture, it should be appreciated that th`e flow of wash liquor through the illustrated machine is opposite to the travel of the pulp mat. More specifically, fresh wash liquor is continuously fed into the second drum 13 via inlet conduit 51 at a sufficient flow rate to keep approximately the lower half of the wash drum 15 filled. Suitable control means, not shown, are preferably provided to insure that this liquor level is maintained. This fresh wash liquor, as previously described, is then forced into the tank 47 through the submerged pulp mat due to the hydrostatic head difference between the interior and exterior of the drum 13. Then, the once-used wash liquor flows from the tank 47 into the first drum ll via the conduit 71. The liquid in the first drum ll then is forced into the first tank 45 by the hydrostatic head in the first drum ll and, followingly, flows to disposal via conduit 69.
It should now be apparent that a machine according to this invention can include more than two pairs of wash drums and tanks, depending upon the number of stages of washing which are required for a particular application.
An embodiment of a particular modification of the aforedescribed machine will now be described in conjunction with Figures 4-6. In this embodiment, elements which are common to the machine in Figure l are designated by the same reference numerals. This embodiment differs from the one described earlier principally with respect to the construction of the wash drums and tanks as well as with respect to the piping within the machine.
.
10~24~S
~ As shown in Figure 4, a machine according to this ¦ embodiment includes two wash cylinders 104 and 105 arranged to rotate in respective tanks 45 and 47 in the same fashion as the wash drums in the earlier-described embodiment. Here, however, the wash cylinders each have a least one open end, not two closed ends as had the aforedescribed wash drums. Thus, as shown by way of example in Figures 5-6, the wash cylinder 104 has a perforate sidewall 19 supported by rigid spokes 106 which extend radially from axle shafts 27 and 29. The spaces between the spokes are open, permitting liquid-flow communication between the associated tank 45 and the interior of the wash cylinder.
The machine in this embodiment further includes ` seai members 107 which are fixedly mounted in pairs in each of the tanks 45 and 47 near the ends of the wash cylinders. As can be best seen in Figures 5 and 6, each seal member is planar and has an arcuate edge l portion which sealingly abuts the sidewall of the -I ~ 20 associated wash cylinder. Each seal member is fixed to extend from sidewall to sidewall of the associated tank across the tank floor. The function of the seal members is to partition the interior of each of the tanks into distinct zones. The zones defined between associated pairs of the seal members, herein referred to as wash spaces 109, are in liquid-flow communication with the interiors of the associated wash cylinders only via the openings in the cylindrical sidewalls.
Pipe 111 is connected to the wash space 109 of tank 47 to introduce liquid thereinto.
A zone defined between a seal member 107 and the adjacent sidewall of the associated tank is herein referred to as discharge space 112. At least one such discharge space is provided in each of the tanks 45 and 47. (The wash cylinder 95 in Figure 5 should be understood to have both of its ends open and, therefore, there are two discharge spaces 112 provided in tank 45.) The discharge spaces are in direct flow communication with the interiors of the associated wash j cylinders via the open ends of the cylinders. The discharge spaces 112, are of course, separated from thè
wash spaces 109 by the seal members 107. Connected in communication within the tank 45 is outlet conduit 115 which functions to withdraw liquid from discharge space 112. Pipe 117 is connected between the wash space 109 of tank 45 and the discharge space 112 of tank 47 to provide liquid flow therebetween.
Referring to Figure 4, the outlet conduit 115 associated with the discharge space 112 in the first tank 45 is connected so that liquid drawn from the interior of the first wash cylinder 104 is carried to discharge. The outlet conduit 117 connected to the discharge spacé 112 in the seco,nd tank 47 is also connected to the wash space 109 of tank 45 so that liquid drawn from the interior of the second wash cylinder 105 is conveyed into the first tank 45.
The operation of the machine in Figure 4 can now be understood with reference, for example, to wash cylinder 105 located in tank 47. Counduit 111 carries liquid into the wash space 109 of tank 47.
I Simultaneously, a pulp mat is carried between the j endless belts 83 and 85 into the tank 47 and, with the belts, passes under the wash cylinder 105. From the ~- wash space 109 in tank 47, liquid flows through the pulp mat into the wash cylinder 105. This flow is due to the hydrostatic head exterior of the wash cylinder exceeding the head within the wash cylinder. Liquid -..--lO9Z405 ; then flows through the open end of the wash cylinder 1 105 and into the discharge space 112. This liquid is ¦ then withdrawn from the discharge space 112 via the outlet conduit 117 and conveyed to tank 45.
' :' , ' - .
¦ BACKGROUND OF THE INVENTION
.
' Field of the Invention . _ - The present invention relates to machines for washing paper stock pulp and other free-filtering ! 5 materials.
.
State of the Art , According to various processes well-known in the -~ paper making industry, paper stock pulp is formed by - digesting wood chips in the presence of various ¦ 10 chemicals in a heated -¦ pressure vessel. After discharge from the `1 pressure vessel, the paper stock pulp must be washed --~, - and filtered to separate the wood fibers from the - digestion chemicals.
According to a conventional system for washing paper stock pulp the pulp is diluted with water after digestion and then is picked up by a large-diameter . rotating cylinder whose surface is formed of a wire mesh screen. A couch roll is positioned to press downward onto the.surface of the screen-covered ; cylinder to express liquid from the stock and thus to ~- form a blanket or mat of dewatered fibers. Such a conventional system further includes an agitation device wherein once-dewatered fibers are repulped by mixing with water. Still further, the system includes additional agitation devices, screen-covered cylinders, and couch rolls to wash the pulp in stages.
-:~
, , 1~92405 I According to other processes well-known in the paper-making industry, materials such as waste paper and ground-wood, although not digested with chemicals, must nevertheless be washed. Conventional systems for such washing are also known.
! ` `- According to still other processes well-known in the papermaking industry paper pulp is bleached by treating the pulp with chemicals such as a solution of chlorine or sodium hydroxide. In other processes chemical solutions are often used to treat the pulp.
.
OBJECTS OF THE INVENTION
The primary object of the present invention is to i provide an improved machine to wash paper stock pulp ¦ and other free-filtering materials. As will be readily understood in view of the following description, the term free-filtering encompasses materials which, ~hen ' covering a filtering surface, allow liquid to pass -l readily there through when a slight hydraulic head is exerted. The term pulp is used herein as a synonym for ` 20 free-filtering materials.
Another object of the present invention is to ~ provide an improved machine for treating pulp with ¦ solutions of chemicals to accomplish bleaching and - other processes. The term "washing" is used herein to include such treatment with chemical solutions, and the term "liquid" includes such chemical solutions.
A more specific object of the present invention is to provide an improved machine for washing pulp, which machine is of the type which operates without interstage pumps.
Yet another object of the present invention is to ~, provide an improved machine for washing pulp which operates without re-pulping of the pulp stock.
;~
~.
- io~240s Still another object of the present invention is i to provide a machine for washing pulp wherein frothing ! of the pulp is substantially minimized.
¦ BRIEF DESCRIPTION OF THE DRAWINGS
j 5 The above and other objects of the present I ` invention may be readily ascertained by consideration ¦ of the following detailed description and appended ! drawings, which are offered by way of illustration only , and not in limitation of the invention, the scope of ¦ 10 which is defined by the appended claims and equivalents.
In the drawings:
i Figure 1 is a side elevation of a machine - according to the present invention shown schematically;
Figure 2 is a view taken along line 2-2 in Figure .' 1 ~! for viewing in the direction of the arrows which ' schematically illustrates one detail of the machine of j Figure 1 partially cut away;
Figure 3 shows a detail of the machine of Figure 1 , enlarged for purposes of clarity;
j Figure 4 is a side elevation of another embodiment i of a machine according to the present invention.
¦ Figure 5 is a view taken along line 5-5 in Figure j 25 4 which schematically shows a detail of the machine of ! `~ Figure 1 partially cut away.
! Figure 6 shows a detail of the machine of Figure 4.
i DETAILED DESCRIPTION OF THE INVENTION
As shown in Figure 1, a machine according to this invention generally includes horizontally-disposed wash drums 11 and 13 which are mounted in spaced-apart, side-by-side relationship. The wash drums are illustrated as being cylinders of equal diameter but, in certain instances, it may be desirable for the wash drums to have different diameters. The wash drums are mounted in vertically stepped relationship to one another so that the central axis of the first drum 11 is lower than the central axis of the second drum 13.
The two illustrated drums are essentially the same in construction and operation and, for that reason, only one wash drum 11 will now be described in detail.
- 15 With reference now to Figures 1 and 2, the wash drum 11 includes a cylindrical sidewall 19 and end closure walls 21 and 23. The cylindrical sidewall is perforated say by small spaced-apart apertures 25 to .
permit liquid to flow freely from the drum. Workers skilled in this art will readily recognize that the side~walls of the drums, instead of being peFforated, could be comprised of a wedgewire grid or other conventional support means which permit liquid flow.
The end closure walls 21 and 23 are nonforaminate.
Axle members 27 and 29 are fixed to the end closure ! ~ walls 21 and 23, respectively, and are supported for rotation outboard of the drum by stationary pillow ' blocks 33 and 35, respectively, or other journal means.
According to the embodiment in Figure 2, a tube 39 is stationarily mounted to extend into the wash drum 11 to introduce liquid into its interior. The illustrated tube 39 has a horizontal section 40 which extends into the drum through the axle member 27, and a leg 42 which extends downward inside the drum.
109Z4~)5 With respect to the machine in Figure 1, tubes 39 and 43 are mounted in communication with the interiors of wash drums 11 and 13 respectively. Tube 43 should be understood to be the same in construction and S operation as the tube 39 described above.
' Referring still to Figure 1, open tanks 45 and 47 are mounted below the respective wash drums 11 and 13.
The tanks are constructed and positioned to encompass the lower half or less of each of the respective wash drums and to contain a substantial quantity of liquid exterior of the wash drums. In practice, the tanks preferably are identical to one another and are mounted in vertically-stepped relationship corresponding to the differential elevations of the wash drums. A plate 49 is connected between the upper-edges of tanks 45 and 47, and a second plate 50 is connected to the upper edge of tank 47 to extend upward therefrom.
A liquid inlet means, such as a conduit 51 shown in Figure 1, is connected in communication with the tube 43 to carry wash liquor into the wash drum 13. In - some applications, the wash liquor may simply be fresh water while in other instances it may be an aqueous solution of particular chemicals or a non-aqueous liquid. As will be understood in view of the following description, the flow of wash liquid is countercurrent to the direction of travel of pulp material through the machine.
I Referring now to Figures 1 and 3, a compression roller member 55 is mounted to the right and above the first wash drum and is supported for rotation by conventional means, not shown. The compression roller member 55 shown in Figure 3 comprises, for example, a rigid hollow cylinder which is formed from wire screen or other foraminous material so that liquid can drain freely through it. Likewise, a second compression :`
.
roller member 57 is rotatably mounted to the right and j above the second wash drum 13. The second roller ¦ member 57 is mounted adjacent the second drum 13 and can be adjustably positioned relative to the second drum. The second roller member 57 is the same in I construction as roller member 55. However, the second j roller member 57 can optio~ally have a rigid, non-foraminate wall.
As further-shown in Figure 1, a conduit 69 is coupled to the tank 47 to carry liquid therefrom to tube 39. A conduit 71 is connected to tank 45 to carry liquid therefrom to disposal.
The machine in Figure 1 further includes feed means which, in the illustrated embodiment by way of example, comprises a horizontal vacuum pan 75 of conventional construction which is mounted to the left of the first wash drum 11. A conventional suction-producing device, not shown, is connected in communication with the interior of the vacuum pan to draw liquid therefrom via a conduit 76. Above the vacuum pan 75 is mounted a distribution box 77, which also is of conventional construction. At the opposite ends of the vacuum pan are rotatably mounted support rollers 79 and 81, respectively. One skilled in this art should readily recognize that the feed means could, alternatively, comprise other conventional means for forming a pulp mat between two belts. For example, the feed means could comprise a conventional vacuum drum means or a conventional system including two belts disposed substantially vertically.
Two endless filter belts 83 and 85, referred to herein as the upper and lower belts respectively, are trained around the wash drums and the compression roller members in zig-zag fashion as illustrated in .
1~)9Z405 Figure l. More particularly, the endless belts are i trained in face-to-face relationship to each other to pass under each of the wash drums 11 and 13 and over each of the compression roller members 55 and 57. The 5 endless belts should be understood to comprise conventional porous filter belts of the type which are well known in the filtration art.
Above the machine, the upper belt 83 is trained over a set of guide rollers 90-94; below the machine, the lower belt 85 is trained over a set of guide -! rollers 95-lO0. Conventional drive means, not shown, , are connected to rotatably drive the roller member 57 and, thus, to cause the two endless belts 83 and 85 to - travel together at equal speeds in the directions indicated by the arrows in Figure 1. The upper and lower sets of guide rollers are positioned to separate the upper and lower belts after the belts have passed over the second compression roller member 57 and, at the opposite end of the machine, to reunite the belts in face-to-face relationship before the belts travel under the first wash drum ll. It should be further ., observed that the lower set of guide rollers 95-100 is positioned so that the lower belt 85 passes around the - support roller 79, then between the vacuum pan 75 and the distribution box 77, and finally over the support roller 81 before reuniting with the upper belt 83. In practice, at least one guide roller in both the upper and lower sets is movably mounted so that the tensions of the belts can be selectively adjusted. Also, ! 30 conventional means for laterally aligning the belts are normally provided.
The operation o the above-described machine can now be understood. Initially a free-filtering material, such as paper stock pulp containing digestion , .
; chemicals, is fed into the distribution box 77 as I indicated by the arrow. That material is then ¦ discharged onto the belt 85 as it travels across the vacuum pan 75. Suction applied through the vacuum pan 75 draws liquid from the pulp, leaving a sheet or mat 102 of partially dewatered fibers lying on the belt 85.
The withdrawn liquid, or filtrate, is discharged from ! the machine via conduit 76. The lower belt 85, after passage across the vacuum pan, meets the upper belt 83 in face-to-face relationship and, thus, the mat of pulp fibers is gripped between the two belts.
Typically, the pulp mat is about one-quarter to one j inch in thickness.
j The two belts 83 and 85, with the pulp mat between j 15 them, then pass into the first tank 45 and under the - first wash drum 11. Simultaneously the wash drum 11 is --rotated, say by frictional engagement with the upper belt 83. At this time, liquid from inside the first drum 11 passes through the pulp mat between the two , - 20 belts and then flows into the tank 45. This flow of liquid through the pulp mat occurs because of the differential in the hydrostatic head (liquid level) between the interior and exterior of the wash drum 11.
The flow of liquid through the pulp mat serves to wash the pulp and, in some instances, also increases the moisture content of the pulp mat because some of the ~ wash liquid is absorbed by the pulp.
¦ The two belts 83 and 85, after passing under the wash drum 11J then pass over the first compression roller member 55. During this stage, the pulp mat is squeezed between the belts due to the tension in the upper belt 83. Liquid, which is thus expressed from -1~)92405 the pulp, drains through the roller member 55 as shown in Figure 3. The expressed liquor is caught by the plate 49 and flows into the tank 45.
After passage over the first compression roller member 55, the two endless belts 83 and 85 carry the pulp mat into the second tank 47 and then under the second wash drum 13. During this stage, the pulp mat undergoes a second wash like the one described above.
Then, the two belts 83 and 85 with the pulp mat therebetween pass over the second compression roller member 57. Thus it can be seen that the pulp mat ~i undergoes two stages of washing and expression. The ¦ second compression roller 57 is positioned relative to the drum 13 so that the two belts are simultaneously ; 15 tangent to both the drum and the roller. The position of the roller 57 is adjusted to compress the pulp mat and express liquid therefrom.
After pressing over the roller 57 the upper and lower belts 83 and 85 are moved apart by the guide rollers 94 and 95 to expose the washed pulp mat. The pulp mat is then discharged from the machine by suitable means, not shown, such as a doctor blade or the like.
As mentioned earlier, the upper and lower belts are held under predetermined tensions by the adjustable I - guide rollers. The tensions need not be the same. In fact, the upper belt 83 is preferably at greater ! tension than the lower belt 85. This causes the compressive force on the pulp mat to be greater when the mat passes over the compression rollers 55 and 57 than when it passes under the wash drums 11 and 13.
This is advantageous because the pulp mat is "worked", i.e., compressed during its passage over the compression roller members and allowed to expand and absorb wash liquid when passing under the wash drums.
!
This working can be likened to wringing a sponge and then allowing it to expand to absorb more water.
At this juncture, it should be appreciated that th`e flow of wash liquor through the illustrated machine is opposite to the travel of the pulp mat. More specifically, fresh wash liquor is continuously fed into the second drum 13 via inlet conduit 51 at a sufficient flow rate to keep approximately the lower half of the wash drum 15 filled. Suitable control means, not shown, are preferably provided to insure that this liquor level is maintained. This fresh wash liquor, as previously described, is then forced into the tank 47 through the submerged pulp mat due to the hydrostatic head difference between the interior and exterior of the drum 13. Then, the once-used wash liquor flows from the tank 47 into the first drum ll via the conduit 71. The liquid in the first drum ll then is forced into the first tank 45 by the hydrostatic head in the first drum ll and, followingly, flows to disposal via conduit 69.
It should now be apparent that a machine according to this invention can include more than two pairs of wash drums and tanks, depending upon the number of stages of washing which are required for a particular application.
An embodiment of a particular modification of the aforedescribed machine will now be described in conjunction with Figures 4-6. In this embodiment, elements which are common to the machine in Figure l are designated by the same reference numerals. This embodiment differs from the one described earlier principally with respect to the construction of the wash drums and tanks as well as with respect to the piping within the machine.
.
10~24~S
~ As shown in Figure 4, a machine according to this ¦ embodiment includes two wash cylinders 104 and 105 arranged to rotate in respective tanks 45 and 47 in the same fashion as the wash drums in the earlier-described embodiment. Here, however, the wash cylinders each have a least one open end, not two closed ends as had the aforedescribed wash drums. Thus, as shown by way of example in Figures 5-6, the wash cylinder 104 has a perforate sidewall 19 supported by rigid spokes 106 which extend radially from axle shafts 27 and 29. The spaces between the spokes are open, permitting liquid-flow communication between the associated tank 45 and the interior of the wash cylinder.
The machine in this embodiment further includes ` seai members 107 which are fixedly mounted in pairs in each of the tanks 45 and 47 near the ends of the wash cylinders. As can be best seen in Figures 5 and 6, each seal member is planar and has an arcuate edge l portion which sealingly abuts the sidewall of the -I ~ 20 associated wash cylinder. Each seal member is fixed to extend from sidewall to sidewall of the associated tank across the tank floor. The function of the seal members is to partition the interior of each of the tanks into distinct zones. The zones defined between associated pairs of the seal members, herein referred to as wash spaces 109, are in liquid-flow communication with the interiors of the associated wash cylinders only via the openings in the cylindrical sidewalls.
Pipe 111 is connected to the wash space 109 of tank 47 to introduce liquid thereinto.
A zone defined between a seal member 107 and the adjacent sidewall of the associated tank is herein referred to as discharge space 112. At least one such discharge space is provided in each of the tanks 45 and 47. (The wash cylinder 95 in Figure 5 should be understood to have both of its ends open and, therefore, there are two discharge spaces 112 provided in tank 45.) The discharge spaces are in direct flow communication with the interiors of the associated wash j cylinders via the open ends of the cylinders. The discharge spaces 112, are of course, separated from thè
wash spaces 109 by the seal members 107. Connected in communication within the tank 45 is outlet conduit 115 which functions to withdraw liquid from discharge space 112. Pipe 117 is connected between the wash space 109 of tank 45 and the discharge space 112 of tank 47 to provide liquid flow therebetween.
Referring to Figure 4, the outlet conduit 115 associated with the discharge space 112 in the first tank 45 is connected so that liquid drawn from the interior of the first wash cylinder 104 is carried to discharge. The outlet conduit 117 connected to the discharge spacé 112 in the seco,nd tank 47 is also connected to the wash space 109 of tank 45 so that liquid drawn from the interior of the second wash cylinder 105 is conveyed into the first tank 45.
The operation of the machine in Figure 4 can now be understood with reference, for example, to wash cylinder 105 located in tank 47. Counduit 111 carries liquid into the wash space 109 of tank 47.
I Simultaneously, a pulp mat is carried between the j endless belts 83 and 85 into the tank 47 and, with the belts, passes under the wash cylinder 105. From the ~- wash space 109 in tank 47, liquid flows through the pulp mat into the wash cylinder 105. This flow is due to the hydrostatic head exterior of the wash cylinder exceeding the head within the wash cylinder. Liquid -..--lO9Z405 ; then flows through the open end of the wash cylinder 1 105 and into the discharge space 112. This liquid is ¦ then withdrawn from the discharge space 112 via the outlet conduit 117 and conveyed to tank 45.
' :' , ' - .
Claims (18)
1. A machine for washing paper stock pulp and other free filtering materials comprising:
a. two or more horizontally-disposed wash drums 11 and 13 each having a sidewall 19 through which liquid can pass, said wash drums 11 and 13 being mounted for rotation about their horizontal axes and disposed in side-by-side, vertically-stepped relationship with the first of said drums being the lowest and the last being the highest;
b. two or more open tanks 45 and 47 mounted to encompass the lower half or less of respective ones of said wash drums 11 and 13, said tanks 45 and 47 being constructed to contain liquid exterior to said wash drums;
c. roller members 55 and 57 mounted for rotation at spaced-apart locations above said wash drums 11 and 13;
d. first and second endless filter belts 83 and 85 trained to pass under each of said wash drums 11 and 13 and over each of said roller members 55 in face-to-face relationship with each other to hold a mat of material 102 to be washed;
e. a first set of guide means 92 mounted above said wash drums 11 and 13 to guide said first endless filter belt 83 from the last of said wash drums to the first of said wash drums, and a second set of guide means 97 mounted below said wash drums 11 and 13 to guide said second endless filter belt 85 from the last of said wash drums to the first of said wash drums;
f. drive means mounted to drive said first and second endless belts; and, g. means 51 and 69 connected in communication with each of said wash drums 11 and 13 and each of said tanks 45 and 47 to form a first body of liquid inside said drums 11 and 13 and a second body of liquid inside said tanks 45 and 47 and to provide a hydrostatic head differential between the first and second bodies of liquid to force the liquid through the material 102 held between said first and second endless belts 83 and 85, thereby to wash the material.
a. two or more horizontally-disposed wash drums 11 and 13 each having a sidewall 19 through which liquid can pass, said wash drums 11 and 13 being mounted for rotation about their horizontal axes and disposed in side-by-side, vertically-stepped relationship with the first of said drums being the lowest and the last being the highest;
b. two or more open tanks 45 and 47 mounted to encompass the lower half or less of respective ones of said wash drums 11 and 13, said tanks 45 and 47 being constructed to contain liquid exterior to said wash drums;
c. roller members 55 and 57 mounted for rotation at spaced-apart locations above said wash drums 11 and 13;
d. first and second endless filter belts 83 and 85 trained to pass under each of said wash drums 11 and 13 and over each of said roller members 55 in face-to-face relationship with each other to hold a mat of material 102 to be washed;
e. a first set of guide means 92 mounted above said wash drums 11 and 13 to guide said first endless filter belt 83 from the last of said wash drums to the first of said wash drums, and a second set of guide means 97 mounted below said wash drums 11 and 13 to guide said second endless filter belt 85 from the last of said wash drums to the first of said wash drums;
f. drive means mounted to drive said first and second endless belts; and, g. means 51 and 69 connected in communication with each of said wash drums 11 and 13 and each of said tanks 45 and 47 to form a first body of liquid inside said drums 11 and 13 and a second body of liquid inside said tanks 45 and 47 and to provide a hydrostatic head differential between the first and second bodies of liquid to force the liquid through the material 102 held between said first and second endless belts 83 and 85, thereby to wash the material.
2. A machine for washing paper stock pulp and other free-filtering materials comprising:
a. two or more horizontally-disposed wash drums 11 and 13 each having a perforated sidewall 19, and end closure walls 21, said wash drums being mounted for rotation about their horizontal axes and disposed in vertically-stepped relationship with the first of said drums being the lowest and the last being the highest;
b. two or more open tanks 45 and 47 mounted and constructed to contain liquid exterior to said wash drums;
c. roller members 55 and 57 mounted for rotation at spaced-apart locations above said wash drums 11 and 13;
d. first and second endless filter belts 83 and 85 trained to pass under each of said wash drums 11 and 13 and over each of said roller members 55 and 57 in face-to-face relationship with each other;
e. a first set of guide means 92 mounted for rotation above said wash drums 11 and 13 to guide said first endless belt 83 from the last of said wash drums to the first of said wash drums, and a second set of guide roller means 97 mounted below said wash drums 11 and 13 to guide said second endless belt 85 from the last of said wash drums to the first of said wash drums;
f. drive means mounted to drive said first and second endless belts to travel under each of said wash drums and over each of said roller members;
g. liquid inlet means 51 to introduce liquid directly into the interior of the highest of said wash drums; and h. outlet means 69 and 71 connected in communication with each of said tanks 45 and 47 to remove liquid from said tanks 45 and 47 to provide a hydrostatic head differential between the interiors of said wash drums 11 and 13 and the liquid contents of the associated said tanks thereby to force liquid from the wash drums into said tanks to wash the material held between said first and second endless belts.
a. two or more horizontally-disposed wash drums 11 and 13 each having a perforated sidewall 19, and end closure walls 21, said wash drums being mounted for rotation about their horizontal axes and disposed in vertically-stepped relationship with the first of said drums being the lowest and the last being the highest;
b. two or more open tanks 45 and 47 mounted and constructed to contain liquid exterior to said wash drums;
c. roller members 55 and 57 mounted for rotation at spaced-apart locations above said wash drums 11 and 13;
d. first and second endless filter belts 83 and 85 trained to pass under each of said wash drums 11 and 13 and over each of said roller members 55 and 57 in face-to-face relationship with each other;
e. a first set of guide means 92 mounted for rotation above said wash drums 11 and 13 to guide said first endless belt 83 from the last of said wash drums to the first of said wash drums, and a second set of guide roller means 97 mounted below said wash drums 11 and 13 to guide said second endless belt 85 from the last of said wash drums to the first of said wash drums;
f. drive means mounted to drive said first and second endless belts to travel under each of said wash drums and over each of said roller members;
g. liquid inlet means 51 to introduce liquid directly into the interior of the highest of said wash drums; and h. outlet means 69 and 71 connected in communication with each of said tanks 45 and 47 to remove liquid from said tanks 45 and 47 to provide a hydrostatic head differential between the interiors of said wash drums 11 and 13 and the liquid contents of the associated said tanks thereby to force liquid from the wash drums into said tanks to wash the material held between said first and second endless belts.
3. A machine according to claim 2 wherein said outlet means 69 and 71 comprises a vacuum receiver.
4. A machine according to claim 2 wherein the one of said outlet means 69 and 71 which is connected to said highest tank is disposed to convey withdrawn liquid into one of said wash drums.
5. A machine according to claim 2 wherein at least one of said outlet means 69 and 71 is connected to discharge withdrawn liquid into the wash drum which is associated with the next lower one of said tanks.
6. A machine according to claim 2 wherein said roller members 55 and 57 each comprise a rigid, hollow cylinder formed from foraminous material which lets liquid drain freely through it.
7. A machine according to claim 2 further including means to adjustably position at least one of the guide means of said first set 92 to thereby adjust the tension in said first endless belt.
8. A machine according to claim 2 further including feed means 77 to form a mat of the material between said endless belts.
9. A machine according to claim 8 wherein said feed means 77 includes (a) vacuum pan means 75 mounted adjacent the lowermost one of said wash drums; (b) means 79 and 81 mounted adjacent the ends of said vacuum pan means to guide said second endless filter belt to pass over said vacuum pan means; and (c) means to form a mat of pulp on the second endless filter belt.
10. A machine according to claim 2 wherein said first belt 83 is at greater tension than said second belt 85 so that a greater compressive force is exerted upon the material held between the two belts when the belts pass over said roller members 55 and 57 than when said belts pass under said wash drums 11 and 13.
11. A machine for washing paper stock pulp and other free-filtering materials comprising:
a. two or more horizontally-disposed wash cylinders 104 and 105 each having a perforated sidewall 19 and at least one open end, said wash cylinders 104 and 105 being mounted for rotation about their horizontal axes and disposed in vertically-stepped relationship with the first of said wash cylinders being the lowest and the last being the highest;
b. open tanks 45 and 47 mounted and constructed to contain liquid exterior to associated ones of said wash cylinders 104 and 105;
c. seal means 107 mounted in each of said tanks 45 and 47 to define in each of said tanks, a first zone 109 contiguous with the perforated sidewall 19 of the associated one of said wash cylinders and a second zone 112 in liquid flow communication with said first zone only through the perforations in the sidewall 19 of the associated said wash cylinder;
d. roller members 55 and 57 mounted for rotation at spaced-apart locations above said wash cylinders;
e. first and second endless filter belts 83 and 85 trained in face-to-face relationship with each other to pass alternatively under each of said wash cylinders 104 and 105 and over each of said roller members 55 and 57;
f. a first set of guide means 92 mounted for rotation above said wash cylinders 104 and 105 to guide said first endless belt 83 from the last of said wash cylinders to the first of said cylinders, and a second set of guide means 97 mounted below said wash cylinders 104 and 105 to guide said endless belt 85 from the last of said wash cylinders to the first of said cylinders;
g. drive means mounted to drive said first and second endless belts to travel under each of said wash cylinders 104 and 105 and over each of said roller members 55 and 57; and h. withdrawal means connected in communication with each of said second zones 112 in each of said tanks 45 and 47 to withdraw liquid from the interiors of said wash cylinders 104 and 105 to provide a hydrostatic differential head between the interiors of said wash cylinders 104 and 105 and the liquid contents of the associated said tank, thereby to force liquid through the belts 83 and 85 and into said wash cylinders 104 and 105 to wash the material held between said first and second endless belts.
a. two or more horizontally-disposed wash cylinders 104 and 105 each having a perforated sidewall 19 and at least one open end, said wash cylinders 104 and 105 being mounted for rotation about their horizontal axes and disposed in vertically-stepped relationship with the first of said wash cylinders being the lowest and the last being the highest;
b. open tanks 45 and 47 mounted and constructed to contain liquid exterior to associated ones of said wash cylinders 104 and 105;
c. seal means 107 mounted in each of said tanks 45 and 47 to define in each of said tanks, a first zone 109 contiguous with the perforated sidewall 19 of the associated one of said wash cylinders and a second zone 112 in liquid flow communication with said first zone only through the perforations in the sidewall 19 of the associated said wash cylinder;
d. roller members 55 and 57 mounted for rotation at spaced-apart locations above said wash cylinders;
e. first and second endless filter belts 83 and 85 trained in face-to-face relationship with each other to pass alternatively under each of said wash cylinders 104 and 105 and over each of said roller members 55 and 57;
f. a first set of guide means 92 mounted for rotation above said wash cylinders 104 and 105 to guide said first endless belt 83 from the last of said wash cylinders to the first of said cylinders, and a second set of guide means 97 mounted below said wash cylinders 104 and 105 to guide said endless belt 85 from the last of said wash cylinders to the first of said cylinders;
g. drive means mounted to drive said first and second endless belts to travel under each of said wash cylinders 104 and 105 and over each of said roller members 55 and 57; and h. withdrawal means connected in communication with each of said second zones 112 in each of said tanks 45 and 47 to withdraw liquid from the interiors of said wash cylinders 104 and 105 to provide a hydrostatic differential head between the interiors of said wash cylinders 104 and 105 and the liquid contents of the associated said tank, thereby to force liquid through the belts 83 and 85 and into said wash cylinders 104 and 105 to wash the material held between said first and second endless belts.
12. A machine according to claim 11 wherein the one of said withdrawal means which is connected in association with said highest wash cylinder 105 is disposed to discharge withdrawn liquid into the one of said tanks 45 associated with the next lower one of said wash cylinders.
13. A machine according to claim 11 further including trough means 49 which are mounted below said respective roller members 55 to catch liquid drainage when said first and second endless drainage belts 83 and 85 pass over said roller members 55 and 57.
14. A machine according to claim 11 wherein said first endless belt 83 is at greater tension than said second belt 85 so that a greater compressive force is exerted upon the material held between said two belts when the belts pass over said roller members 55 and 57 than when said belts pass under said wash drums 104 and 105.
15. A method of washing paper stock pulp ond other free-filtering materials in a machine including two or more wash drums 11 and 13 mounted in associated open tanks 45 and 47 which contain liquid exterior of the wash drums, which drums have perforated sidewalls 19 and are arranged in vertically-stepped relationship to one another, the first drum being the lowest and the last being the highest, said method comprising:
a. training a pair of endless filter belts 83 and 85 in face-to-face relationship to pass under each of said wash drums 11 and 13;
b. forming a mat of the material 102 between the two belts 83 and 85;
c. driving the two belts 83 and 85 to carry the mat of material 102 under each of the drums 11 and 13 from the first to the last;
d. forming a first body of liquid in each drum 11 and 13 and a second body of liquid in each tank 45 and 47, and maintaining a hydrostatic head differential between the two bodies of liquid to cause the liquid to flow through the mat of material 102 whereby the mat is washed by the liquid;
e. conveying without pumping, the once-used liquid from the tank associated with the last drum to the pulp mat associated with a lower drum;
f. removing the washed mat of material from between the two belts 83 and 85 after the belts 83 and 85 have passed under the last drum; and, g. removing the liquid from the tank associated with the first drum.
a. training a pair of endless filter belts 83 and 85 in face-to-face relationship to pass under each of said wash drums 11 and 13;
b. forming a mat of the material 102 between the two belts 83 and 85;
c. driving the two belts 83 and 85 to carry the mat of material 102 under each of the drums 11 and 13 from the first to the last;
d. forming a first body of liquid in each drum 11 and 13 and a second body of liquid in each tank 45 and 47, and maintaining a hydrostatic head differential between the two bodies of liquid to cause the liquid to flow through the mat of material 102 whereby the mat is washed by the liquid;
e. conveying without pumping, the once-used liquid from the tank associated with the last drum to the pulp mat associated with a lower drum;
f. removing the washed mat of material from between the two belts 83 and 85 after the belts 83 and 85 have passed under the last drum; and, g. removing the liquid from the tank associated with the first drum.
16. A method of washing paper stock pulp and other free-filtering materials in a machine including two or more wash drums 11 and 13 mounted in associated open tanks 45 and 47 which contain liquid exterior of the wash drums 11 and 13, which drums have perforated sidewalls 19 and are arranged in vertically-stepped relationship to one another, the first drum being the lowest and the last being the highest, and further including roller members 55 and 57 mounted for rotation at spaced-apart locations above each of said wash drums 11 and 13, said method comprising:
a. training an upper and a lower filter belt 83 and 85 in face-to-face relationship to pass under each of said filter drums and 11 and 13 over each of said roller members 55 and 57;
b. forming a mat of the material 102 between the two belts;
c. driving the two belts 83 and 85 to carry the mat of material 102 under each of the drums 11 and 13 and over each of the rollers 55 and 57 from the first drum to the last drum;
d. introducing liquid into the interior of the last said drum 13 to flow through the perforated sidewall 19 of that drum and then through the mat 102 into the tank 47 associated with that drum, whereby the mat is washed by the liquid;
e. conveying without pumping, the once-used liquid from the tank associated with the last drum 13 to the interior of a lower drum 11;
f. removing the washed mat of material from between the two belts 83 and 85 after the belts 83 and 85 have passed over the roller member 57 associated with the last drum 13, and g. removing the liquid from the tank 47 associated with the first drum.
a. training an upper and a lower filter belt 83 and 85 in face-to-face relationship to pass under each of said filter drums and 11 and 13 over each of said roller members 55 and 57;
b. forming a mat of the material 102 between the two belts;
c. driving the two belts 83 and 85 to carry the mat of material 102 under each of the drums 11 and 13 and over each of the rollers 55 and 57 from the first drum to the last drum;
d. introducing liquid into the interior of the last said drum 13 to flow through the perforated sidewall 19 of that drum and then through the mat 102 into the tank 47 associated with that drum, whereby the mat is washed by the liquid;
e. conveying without pumping, the once-used liquid from the tank associated with the last drum 13 to the interior of a lower drum 11;
f. removing the washed mat of material from between the two belts 83 and 85 after the belts 83 and 85 have passed over the roller member 57 associated with the last drum 13, and g. removing the liquid from the tank 47 associated with the first drum.
17. The process of claim 16 further including the step of maintaining the upper belt 83 at a higher tension than the lower belt 85.
18. The process of claim 16 further including the step of applying greater pressure to the mat of material 102 as it passes over the rollers 55 and 57 than as it passes under the drums 11 and 13 in order to sequentially compress the mat 102 and allow it to expand.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/853,068 US4160297A (en) | 1977-11-21 | 1977-11-21 | Pulp washer |
| US853,068 | 1977-11-21 | ||
| US951,540 | 1978-10-16 | ||
| US05/951,540 US4246669A (en) | 1978-10-16 | 1978-10-16 | Dual belt pulp washer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1092405A true CA1092405A (en) | 1980-12-30 |
Family
ID=27127113
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA316,488A Expired CA1092405A (en) | 1977-11-21 | 1978-11-20 | Dual belt pulp washer |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS54500055A (en) |
| AR (1) | AR220159A1 (en) |
| CA (1) | CA1092405A (en) |
| FI (1) | FI69327C (en) |
| NO (1) | NO154136C (en) |
| SE (1) | SE422817B (en) |
| WO (1) | WO1979000309A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1980000460A1 (en) * | 1978-08-18 | 1980-03-20 | Envirotech Corp | Twin belt vacuum washer |
| AT385790B (en) * | 1986-09-17 | 1988-05-10 | Andritz Ag Maschf | DEVICE FOR TREATING A BETWEEN AT LEAST TWO ENDLESS PERMANENT TAPES, e.g. SCREENBAND, GUIDED MATERIALS |
| AT386850B (en) * | 1986-09-17 | 1988-10-25 | Andritz Ag Maschf | DEVICE FOR TREATING A BETWEEN AT LEAST TWO ENDLESS PERMANENT TAPES, e.g. SCREENBAND, GUIDED MATERIALS |
| DE4018120A1 (en) * | 1990-06-06 | 1991-12-12 | Bernt U Treu | Cellulose washing |
| US5513956A (en) * | 1994-01-14 | 1996-05-07 | Arrow International Investment Corp. | Circulatory assisted device with motor driven gas pump |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL76401C (en) * | ||||
| US899440A (en) * | 1905-12-29 | 1908-09-22 | Walter Erben | Apparatus for extracting grease and potash salts from wool. |
| US2745712A (en) * | 1953-10-22 | 1956-05-15 | Improved Machinery Inc | Process for countercurrent washing of cooking liquor out of pulp |
| DE2121722A1 (en) * | 1971-05-03 | 1972-11-23 | Vepa Ag, Riehen, Basel (Schweiz) | Impregnating appts - partic for uniformly impregnating a binding agent into fleece |
| FR2147894B1 (en) * | 1971-08-04 | 1974-10-11 | Neyrpic Bmb | |
| US3857261A (en) * | 1973-08-27 | 1974-12-31 | Riggs & Lombard Inc | Textile scouring range |
-
1978
- 1978-11-17 NO NO783875A patent/NO154136C/en unknown
- 1978-11-20 WO PCT/US1978/000165 patent/WO1979000309A1/en unknown
- 1978-11-20 FI FI783528A patent/FI69327C/en not_active IP Right Cessation
- 1978-11-20 JP JP50015078A patent/JPS54500055A/ja active Pending
- 1978-11-20 CA CA316,488A patent/CA1092405A/en not_active Expired
- 1978-11-21 AR AR274523A patent/AR220159A1/en active
-
1979
- 1979-07-19 SE SE7906221A patent/SE422817B/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| FI783528A (en) | 1979-05-22 |
| WO1979000309A1 (en) | 1979-06-14 |
| SE422817B (en) | 1982-03-29 |
| NO783875L (en) | 1979-05-22 |
| NO154136B (en) | 1986-04-14 |
| FI69327C (en) | 1986-01-10 |
| FI69327B (en) | 1985-09-30 |
| AR220159A1 (en) | 1980-10-15 |
| JPS54500055A (en) | 1979-11-08 |
| NO154136C (en) | 1986-07-23 |
| SE7906221L (en) | 1979-07-19 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |