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

Definitions

• the present invention relates to machines for washing paper stock pulp and other free-filtering materials.
• paper stock pulp is formed by digesting wood chips in the presence of various chemicals in a heated pressure vessel. After discharge from the pressure vessel, the paper stock pulp must be washed and filtered to separate the wood fibers from the digestion chemicals.
• 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.
• the system includes additional agitation devices, screen-covered cylinders, and couch rolls to wash the pulp in stages.
• 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.
• paper pulp is bleached by treating the pulp with chemicals_ such as a solution of chlorine or sodium hydroxide.
• chemicals_ such as a solution of chlorine or sodium hydroxide.
• chemical solutions are often used to treat the pulp.
• the primary object of the present invention is to provide an improved machine to wash paper stock ' pulp and other free-filtering materials.
• free-filtering encompasses materials which, when covering a filtering surface, allow liquid to pass readily there through when a slight hydraulic head is exerted.
• pulp is used herein as a synonym for 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.
• 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.
• Still another object of the present invention is to provide a machine for washing pulp wherein frothing of the pulp is substantially minimized.
• 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 Figure 1 partially cut away;
• Figure 3 shows a detail of the machine of Figure 1 enlarged for purposes of clarity;
• Figure 4 is a side elevation of another embodiment of a machine according to the present invention.
• Figure 5 is a view taken along line 5-5 in Figure 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.
• a machine 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.
• 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.
• the sidewalls of the drums instead of being perforated, 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.
• 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.
• 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 operation as the tube 39 described above.
• 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.
• 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.
• 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.
• the flow of wash liquid is countercurrent to the direction of travel of pulp material through the machin .
• 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.
• a second compression roller member 57 is rotatably mounted to the right and 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 construction as roller member 55. However, the second roller member 57 can optionally have a rigid, non-for minate wall.
• 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.
• the feed means could, alternatively, comprise other conventional means for forming a pulp mat between two belts.
• 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 are trained around the wash drums and the compression roller members in zig-zag fashion as illustrated in Figure 1. More particularly, the endless belts are trained in face-to-face relationship to each other t ⁇ pass under each of the wash drums 11 and 13 and over each of the compression roller members 55 and 57.
• the endless belts should be understood to comprise conventional porous filter belts of the type which are well known in the filtration art.
• 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 95-100.
• Conventional drive means 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 11.
• 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.
• 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.
• conventional means for laterally aligning the belts are normally provided.
• a free-filtering material such as paper stock pulp containing digestion chemicals
• 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
• 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.
• the pulp mat is about one-quarter to one inch in thickness.
• the two belts 83 and 85 after passing under the wash drum 11, 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 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.
• 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 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 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.
• 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.
• the upper and lower belts are held under predetermined tensions by the adjustable guide rollers.
• the tensions need not be the same.
• the upper belt 83 is preferably at greater tension than the lower belt 85. This causes the co pressive 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.
• 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 11 via the conduit 71. The liquid in the first drum 11 then is forced into the first tank 45 by the hydrostatic head in the first drum 11 and, followingly, flows to disposal via conduit 69.
• 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.
• 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.
• the wash cylinders each have a least one open end, not two closed ends as had the aforedescribed wash drums.
• 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 seal members 107 which are fixedly mounted in pairs in each of the tanks 45 and 47 near the ends of the wash cylinders.
• each seal member is planar and has an arcuate edge portion which sealingly abuts the sidewall of the 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 cylinders via the open ends of the cylinders.
• the discharge spaces 112 are of course, separated from the wash spaces 109 by the seal members 107.
• Outlet conduit 115 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.
• 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 space 112 in the second 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.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Paper (AREA)
• Detergent Compositions (AREA)
• Cleaning By Liquid Or Steam (AREA)

Priority Applications (2)

Applications Claiming Priority (3)

Publications (1)

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ID=27127113

Family Applications (1)

Country Status (7)

Cited By (5)

Citations (6)

• 1978
  • 1978-11-17 NO NO783875A patent/NO154136C/no unknown
  • 1978-11-20 WO PCT/US1978/000165 patent/WO1979000309A1/en unknown
  • 1978-11-20 FI FI783528A patent/FI69327C/fi not_active IP Right Cessation
  • 1978-11-20 CA CA316,488A patent/CA1092405A/en not_active Expired
  • 1978-11-20 JP JP50015078A patent/JPS54500055A/ja active Pending
  • 1978-11-21 AR AR274523A patent/AR220159A1/es active
• 1979
  • 1979-07-19 SE SE7906221A patent/SE422817B/sv not_active IP Right Cessation

Patent Citations (6)

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