Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
  • D21C9/02—Washing ; Displacing cooking or pulp-treating liquors contained in the pulp by fluids, e.g. wash water or other pulp-treating agents
  • D21C9/06—Washing ; Displacing cooking or pulp-treating liquors contained in the pulp by fluids, e.g. wash water or other pulp-treating agents in filters ; Washing of concentrated pulp, e.g. pulp mats, on filtering surfaces
• • 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
  • B01D33/09—Filters with filtering elements which move during the filtering operation with rotary cylindrical filtering surfaces, e.g. hollow drums arranged for inward flow filtration with surface cells independently connected to pressure distributors
• • 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
  • B01D33/463—Regenerating the filter material in the filter by scrapers, brushes nozzles or the like acting on the cake-side of the filtering element nozzles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D33/00—Filters with filtering elements which move during the filtering operation
  • B01D33/44—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
  • B01D33/58—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element
  • B01D33/60—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element for washing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D33/00—Filters with filtering elements which move during the filtering operation
  • B01D33/58—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element
  • B01D33/62—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element for drying
  • B01D33/64—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element for drying by compression
  • B01D33/644—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element for drying by compression by pressure plates, membranes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D33/00—Filters with filtering elements which move during the filtering operation
  • B01D33/58—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element
  • B01D33/62—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element for drying
  • B01D33/64—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element for drying by compression
  • B01D33/646—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element for drying by compression by pressure rollers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D33/00—Filters with filtering elements which move during the filtering operation
  • B01D33/58—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element
  • B01D33/62—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element for drying
  • B01D33/66—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element for drying by gases or by heating
  • B01D33/663—Handling the filter cake in the filter for purposes other than for regenerating the filter cake remaining on the filtering element for drying by gases or by heating by direct contact with a fluid
• • 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
  • B01D33/70—Filters with filtering elements which move during the filtering operation having feed or discharge devices
  • B01D33/76—Filters with filtering elements which move during the filtering operation having feed or discharge devices for discharging the filter cake, e.g. chutes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2201/00—Details relating to filtering apparatus
  • B01D2201/28—Position of the filtering element
  • B01D2201/282—Filtering elements with a horizontal rotation or symmetry axis
• • 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
  • B01D33/70—Filters with filtering elements which move during the filtering operation having feed or discharge devices
  • B01D33/72—Filters with filtering elements which move during the filtering operation having feed or discharge devices for feeding
  • B01D33/722—Filters with filtering elements which move during the filtering operation having feed or discharge devices for feeding containing fixed liquid displacement elements or cores
• • 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
  • B01D33/80—Accessories
  • B01D33/801—Driving means, shaft packing systems or the like
• • 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
  • B01D33/80—Accessories
  • B01D33/804—Accessories integrally combined with devices for controlling the filtration
  • B01D33/808—Accessories integrally combined with devices for controlling the filtration by pressure measuring

Definitions

• the invention concerns so-called drum washers, which are used especially for washing pulp suspensions in the cellulose industry.
• cylinder washers there is a rotatable cylindrical drum, which is pervious to the washing liquid and onto the case of which pulp to be washed is fed constantly to form a mat. Washing liquid is conducted onto the top of the mat and it then passes through the mat and the case, entering the drum, from which it is removed by way of the drum end. The washed pulp is worked loose and removed from the case.
• Such drum washers are also known wherein the filtrate obtained in a final washing stage is recovered within the drum with the aid of a special collecting trough. This filtrate is then reused as washing liquid for the initial stage.
• Such a device is described, for example, in a brochure by the name of Kunststoffa-Repola Pro-feed Pressure Washers, Kunststoffa 1985.
• the purpose of this invention is primarily to bring about a two-step cylinder washer having a technically reliable but simple system for collecting the filtrate in the final washing step.
• the purpose of the invention is achieved by the means presented in Claim 1.
• the other claims present advantageous applications of the invention.
• FIG. 1 is an end view of the washer and washing process looking from the end of the washing drum;
• FIG. 3 shows an end view from the drum end of the second-step washing liquid collecting equipment placed on the drum shaft
• FIG. 4 shows the other drum end and its washing liquid collecting equipment as seen obliquely from the end.
• the main washer components are a basin 1 attached to the body, a filtering drum 2 rotatable within the basin, an assembly 3 for feeding pulp to be washed, an assembly 4 for supplying washing water, piping 5 for circulating washing water, an assembly 6 for removing washing water and an assembly 7 for removing washed pulp.
• a cylindrical case 9 permeable to washing water is attached to the shaft 8 within the filtering drum.
• the shaft ends protrude from the open ends of the drum into bearings mounted on the body. The drum rotates clockwise as seen in Figure 1.
• the case 9 ends have flanges 10. On the exterior side of these there are sealing means 11 matching with the basin ends ( Figure 2) . Pulp 12 to be washed is fed into the basin and through the assembly 13 to an approximate four - five o'clock position in relation to the axis of rotation.
• the pulp flow 12 supplied into the basin is guided to form a mat against the drum case 9 with the aid of a guiding plate 14 which is parallel with the case.
• the front end of the guiding plate is journalled tightly in the bottom wall 15 of the basin on a shaft 16 which is parallel with the drum shaft.
• the distance of the guiding plate from the drum periphery can be adjusted by bars 17.
• a follower plate 18 is located after the guiding plate. Its back end is journalled tightly on shaft 20 in a partition wall 19.
• the partition wall is located in an approximate eight - nine o'clock position in the rotational direction of the drum.
• the distance between follower plate and drum periphery is adjustable by using bars 21.
• a gap 22 is left between the plates.
• the bottom wall 15 of the basin, the guiding plate 14, the follower plate 18 and the partition 19 form a feeding space 23 for washing water. Washing water is supplied into this space by way of an assembly 24. The washing water passes through the gap 22 on to the pulp mat and further through the mat and through the drum periphery, entering the drum.
• a flexible lip 25 forms an extension of the back edge of the guiding plate 14 and it is compressed on to the follower plate 18 from the drum side. It functions as a flap valve in gap 22 to prevent pulp from entering the washing water feeding space 23. Below the lip the lip is provided with support forks 26 articula ⁇ ted to the follower plate. Their free ends are located on top of the guiding plate extension.
• a pulp mat compression plate 28 forms an extension to the follower plate 18.
• the upper part of the basin is closed tightly by a hood 27.
• washing water feeding box 29 The bottom wall 15 of the basin, its partition 19 and the hood 27 mark the limits of a second-step washing water feeding box 29. Washing water can be fed into the box through an assembly
• a partition 31 in the hood and a sealing means 32 which presses against the pulp mat and consists of a roller rotating against the mat.
• a positive pressure for example, 0.3 bar
• the positive pressure assists in moving washing water through the mat.
• a device 34 for detaching the mat is located behind the sealing means 32 to remove the mat from the drum into a chute 35.
• the pulp is removed from the chute into line 36 with the aid of a screw conveyor.
• the chute may also be equipped with pulp mat comminutor means 37, for example, suitable obstacles. Diluting water is also supplied into the chute through an assembly 38.
• the filtrate accumulated on the drum bottom exits by way of an aperture 39 in the basin end.
• the top edge of the pulp feeding assembly 13 is sealed against the drum periphery.
• an overflow area 40 is formed which assists in keeping the filtrate level in the drum at a constant level.
• the water passing through the drum also cleans the holes in the case 9 removing any attached fibres. Due to the positive pressure in the chamber, air passes above the overflow area from the region 41 and through the holes, thus also cleaning the holes. There is also a cleaning scraper 42 in front of the overflow area.
• the filtrate obtained from the upper part of the drum in the final washing stage is cleaner than the filtrate of the early stage.
• This cleaner filtrate is recovered separately into collecting troughs 44, which are located below the drum shaft ends and from which the filtrate is removed along lines 45.
• the drum shaft 8 has two fixed similar circular-based cones 46 located with their bases against one another.
• a flange 47 extends along their base seam and is attached to the drum case 9 with radial support bars so that air is admitted between the case and the flange.
• Vanes 48 are attached to the surface of each cone 46.
• the vanes are essentially triangular. There is a straight gap between the vane and the drum case 9.
• Filtrate entering through the drum case 9 in the upper part of the drum falls down onto the vanes 48 and runs along these onto the cone 46 surface and further into the collecting trough 44 located under the shaft 8 end.
• vanes 48 are not located radially, but they are turned slightly backwards in the rotational direction. In this way that sector is reduced from which the filtrate is collected. In the embodiment shown in the figures, filtrate collection begins at approximately 45° before the top position of the vane.
• the vanes 48 may be provided with grooves or corrugations 49, which guide the flow toward the cone 46 surface ( Figure 2).
• the vane rigidity is increased at the same time.
• a suitable rotational speed is, for example, 0.5 - 6 revolutions per minute.
• the cleaner filtrate collected into the troughs 44 can be used, for example, by the same washer as washing liquid supplied to the first step.
• the pressurized air which is conducted into the hood 27 is taken from the pulp exit side from a pulp screw space limited by the partition 31 by way of the line 51 and using a pump 50. In this way, a low pressure is created on the exit side to further the transfer of washing water and the removal of pulp from the case 9.
• a cleaning scraper 52 may be connected for use in connection with the sealing roller 32.
• the washing water feeding space 23 and the air space in the hood 27 are interconnected by a pressure pipe 53.
• the positive pressure within the hood is made to affect the feeding space 23 as well.
• the pipe functions as a safety device, balancing the water pressure within the feeding space 23.
• Pressure indicators are connected to the assembly at various points for allowing adjustment e.g. of the pressure and of the speed of rotation according to their indications, when required.
• the described system for collecting filtrate in the second step can easily be constructed to operate reliably.
• a significant additional advantage is that the drum's strength can be essentially increased.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Paper (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=8532722

Family Applications (1)

Country Status (6)

Cited By (3)

Families Citing this family (9)

Citations (2)

Family Cites Families (12)

• 1991
  • 1991-06-17 FI FI912919A patent/FI88939C/fi active IP Right Grant
• 1992
  • 1992-06-17 JP JP51075692A patent/JP3160614B2/ja not_active Expired - Fee Related
  • 1992-06-17 AU AU18977/92A patent/AU1897792A/en not_active Abandoned
  • 1992-06-17 CA CA002109574A patent/CA2109574A1/en not_active Abandoned
  • 1992-06-17 WO PCT/FI1992/000188 patent/WO1992022703A1/en active Application Filing
  • 1992-06-17 US US08/142,335 patent/US5460019A/en not_active Expired - Fee Related

Patent Citations (2)

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