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WO1979000765A1 - Filtre a tambour rotatif et sa methode de nettoyage - Google Patents

Filtre a tambour rotatif et sa methode de nettoyage Download PDF

Info

Publication number
WO1979000765A1
WO1979000765A1 PCT/US1979/000166 US7900166W WO7900765A1 WO 1979000765 A1 WO1979000765 A1 WO 1979000765A1 US 7900166 W US7900166 W US 7900166W WO 7900765 A1 WO7900765 A1 WO 7900765A1
Authority
WO
WIPO (PCT)
Prior art keywords
filter
sector
drum
vacuum
filtrate
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.)
Ceased
Application number
PCT/US1979/000166
Other languages
English (en)
Inventor
W Wegener
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Envirotech Corp
Original Assignee
Envirotech Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from US05/886,837 external-priority patent/US4157301A/en
Application filed by Envirotech Corp filed Critical Envirotech Corp
Publication of WO1979000765A1 publication Critical patent/WO1979000765A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D33/00—Filters with filtering elements which move during the filtering operation
    • B01D33/06—Filters with filtering elements which move during the filtering operation with rotary cylindrical filtering surfaces, e.g. hollow drums
    • B01D33/067—Construction of the filtering drums, e.g. mounting or sealing arrangements
    • 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

Definitions

  • This invention relates to rotary vacuum filters and in particular to improved ways and means for effective washing of the filter cloth without interrupting the filtration operation.
  • wash liquor (filtrate) need only be displaced directly from the manifold through the cloth.
  • An even further object is the provision of a drum con ⁇ struction in which the manifold is secured to the inside surface of the drum in such a manner that it is a structural part of the drum contributing to the strength thereof and eli ⁇ minating piping between the manifold and filter sectors on the drum surface.
  • the filter valve is set so that as each sector initiates re-entry into submergence in the slurry, it is subjected to vacuum for a short time suffi ⁇ cient to fill the sector, and associated hydraulic system, in ⁇ cluding manifolds and conduits with filtrate then, while the sector is still submerged, a positive pressure is applied to force a portion of filtrate from the system back through the filter medium into the tank.
  • Pressure for the backwash can be provided by either gas or liquid or. both supplied through the filter valve and hydraulic system. In special cases where blinding is especially stubborn, additional cleaning can be accomplished by supplying additional solvent to the cloth.
  • This reverse flow or backwash dislodges solids from the cloth.
  • additional gas or liquid it is selected to be com ⁇ patible with the material being filtered.
  • a clear solution of the solvent may be used.
  • the backwash is accomplished at virtually no solvent cost. This is so because the liquid used for backwash is drawn from the slurry and is returned thereto without loss or dilution of the slurry.
  • the filter In order to insure that a sufficient volume of filtrate is available for backwash, the filter is constructed with internal manifolds between the surface sectors and the valve. The proper volume of wash liquid will be determined empirically and the conditions of backwash adjusted accordingly.
  • valve again sub ⁇ jects the sector to vacuum and it resumes normal operation whereby filtrate is drawn through the cloth while solids dep on the surface thereof and after emergence from the slurry t cake is washed, further dried and discharged.
  • FIG. 1 is a perspective view of a rotary drum filter embodying the invention
  • FIG. 2 is a front elevational view of a filter valve embodying the invention
  • FIG. 3 is a side sectional view of the valve shown in Fig. 2 taken in the plane of line 3-3 of Fig. 2 and looking in the direction of the arrows;
  • FIG.'s 4-8 are simplified sectional views of a single filter sector going through an operating sequence in which the filter cloth is backwashed pursuant to the invention
  • FIG. 9 is a partial sectional view of the drum taken as looking lengthwise of the drum of Fig. 1 adjacent the surfac
  • FIG. 10 is an elevational view of a part of the drum surface of the drum of Fig. 9 looking in the direction of arrows 10, the drainage grid being omitted for clarity;
  • FIG. 11 is a partial sectional view of the structure of Fig. 10 taken as looking in the direction of arrows 11 of Fig. 10.
  • the drawings illustrate a solvent oil dewaxing filter adapted to separating solidified wax from a chilled crude oi and solvent mixture in which it was initially dissolved at higher temperatures.
  • the basic filter (1) comprises a vat or tank (2) ; a cylin ⁇ drical drum (3) in the tank journalled for rotation therein by trunnions (4), on the drum and.bearings on the tank endwalls.
  • a cover (7) closes the vat with the drum inside. Inspection can be made through any of the glass covered ports (8) .
  • feed slurry to be filtered is introduced into the vat (2) by a convenient inlet and a constant level is main ⁇ tained therein in accordance with standard practice.
  • the surface of the drum is divided longitudinally extending divi- sion strips (9) and outwardly extending end flange (10) into a plurality of individual filtration sectors (11) .
  • Each sector contains a drainage grid (12) overlain by a filter medium (13) held in place by the usual caulking.
  • the sectors continuously pass into submergence in the tank where cake is formed on the drum surface while filtrate is pulled through the cloth.
  • the drum rotates out of emergence and may be subjected to further washing and drying, all under the influence of vacuum originating in a usual pump, not shown, and communicated to the filter sector through the valve (14) then through axial ports in the trunnion (4) , in ⁇ ternal conduit (16) , manifold (17) and ports (18) in the individual sectors (11) .
  • Vacuum applied to the valve (14) through the large flanged openings (21) is maintained continually in the large valve chamber (15) whence it communicates through the trunnion ports whenever those ports rotate into registration with the chamber (15).
  • the ports are subject to vacuum whenever they are not covered by bridge blocks or directly connected to a separ ⁇ ate pressure zone such as shown at (23) .
  • Fig.'s 4-8 illustrate operation of the filter through the wash cycle.
  • the trunnion lead port (24) passes the small opening (26) in th bridge block and vacuum is cut off but the trail port (27) the trunnion registers with another small hole (28) in the block and vacuum is then applied to the trailing outlets (1 of the sector until the trail piping is filled. Further rotation brings both lead and trail ports (24) and (27) int registration with the openings (29) which communicate to a pressure source through the pressure zone, (23) and conduit (31) . The application of pressure forces the thin cake off the drum surface and is continued until the preselected vol of filtrate in the hydraulic system is forced through the f cloth back into the tank.
  • the filtrate backflow through the submerged filter clo is a dynamic and uniformly distributed wash which acts even across the entire sector. This method will be useful in an filtration operation where cake formation occurs quickly so there will be ample time to conduct backwash and to reform the cake after backwash. Once the backflow has been completed, continued drum rotation brings successive sectors into register with the large vacuum chamber to effect cake formation and drying pr • to discharge.
  • each sector (11) is p vided with lead and trail ports (18) adjacent its leading a trailing edges.
  • lead and trail h reference to the direction of drum rotation.
  • all lead ports of a single sector communicate with a common lead manifold (17) and all trail ports of a sector with a common trail manifold (17) .
  • a single conduit (16) then
  • OMPI connects each manifold with one of the ports in the trunnion which in turn connect through a valve to a vacuum source.
  • This single pipe arrangement reduces the number of internal pipes and enables the use of larger pipes ' and ports in the trunnion thus enhancing hydraulic efficiency of the filter.
  • the manifolds are rectangular. Each manifold of a given sector is located as close as possible to the adjacent mani ⁇ fold of an adjacent sector with the junction therebetween, preferably directly under a division strip. Thus, the trail manifold of any sector is located next to the lead manifold of the next succeeding sector; and the centerline between the manifolds is under the division strip (9) between sectors.
  • the manifolds are utilized as structural members for the drum by securing them along their length, either with a continuous weld or a series of tack welds to the interior wall of the drum. Also, the ports in the drum wall and those in the top wall of the manifold are in registration with each other and their peripheral edges are sealed together, usually by welding.
  • a plurality of both lead and trail ports (18) is provided in each sector.
  • the ports are formed as elongated slots located as close as possible and parallel to a division strip. This insures presentation of maximum opening for liquid flow when the port is on the low side of the sector. Also, the slotted port is quite easy to seal weld to a corresponding port in the top wall of the manifold with which it registers to provide communication with the manifold.
  • the slot location is important. As shown, one side of the slot should be close aboard the top edge of the manifold sidewall. This will keep one or more slots adjacent the lower edge of the sector at all times while the drum is out of the slurry, whether the sector is ascending of descending thus enhancing filtrate removal.
  • the slot location is also an aid to cake discharge by gas blowback through the trail slot. This is so because when a sector is descending to the discharge level the trail port is at the top and the manifold acts to trap and retain residual or entrain moisture that would otherwise be carried back into the filte cake when pressured gas is supplied through the trail port f cake discharge.
  • location of the ports at the extre opposite sides of the sector insures sweeping of the complet sector during purge when positive pressured gas is introduce through the trail slot and withdrawn under vacuum through th descending lead slot. Complete sweeping is further enhanced by staggering the lead and trail ports with respect to each other as shown in Fig. 10.
  • the filter is provided with a drainage grid (12) secure between the division strips (9) and a filter cloth (13) suit ably secured in place by conventional caulking and wire windings.
  • a usual deflector blade to guide discharged cake into a cake removal scroll or other conveyor is provided.
  • the configuration and physical location of the manifold are important for two reasons. First, they provide an impro drum construction because they are secured to the inner drum surface and there are no intervening conduits.- Secondly, an this is very important to the cyclic wash operation, the man folds provide a reservoir of wash liquor (filtrate) just adjacent the filter sector. This means that very little ene is wasted by drawing in the necessary wash volume and very little reverse flow is required to effect uniform flow of th necessary small volume of filtrate for cloth wash. Thus, it adjacent that use of the " manifold as a wash liquor reservoir directly adjacent the filtration sector which minimizes back- wash cycle time and energy consumption.
  • the invention has primary application in dewaxing oper ⁇ ations where there is danger of rapid blinding of the cloth by the solids being separated. While the invention is capable of and has been described as occurring every cycle, it may be operated at a lower fre ⁇ quency as the need is determined empirically. In any event, the improved wash reduces down time, increases filtration rate, and increases cloth life. In the case of separation of wax from crude oil and solvent, reduction in shutdown reduces wear and tear on materials of construction because the extreme variations in temperatures between hot wash (180°F.) and normal operation (as low as -15°F.) are drastically reduced.
  • the invention is not limited to filters having both lead and trail ports, but is readily adaptable to various types of hydraulic systems. Also, in the illustrated embodiment, it is not necessary that both lead and trail systems be- used for backwash as either may be used alone. Nor is it necessary that both lead and trail systems be used simultaneously for backwash as it may be desirable to have them backflow in series to effect a prolonged wash. All such variations are within the scope of this invention.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Filtration Of Liquid (AREA)

Abstract

Filtre a aspiration rotatif dans lequel, chaque unite de filtration (11) du filtre est lavee a contre-courant avec le filtrat et/ou separement avec du gaz ou du liquide de lavage pendant que l'unite est immergee dans la pate dans le reservoir. Lorsque chaque unite commence a s'immerger de nouveau dans le reservoir, on exerce une aspiration pour que l'unite et le systeme hydraulique associe se remplisse rapidement et completement de filtrat et qu'un gateau mince ou une couche de particules solides se forme sur l'element filtrant (13) puis, l'unite etant toujours immergee, on stoppe l'aspiration et on applique une pression positive par l'intermediaire du gaz et/ou liquide de pression dont l'alimentation se fait par la vanne (14), forcant ainsi le filtrat a repasser a travers le filtre pour en effectuer le lavage. Apres lavage, on exerce a nouveau une aspiration pour former le gateau. Le tambour (3) comprend un collecteur interne (17) sous chaque unite de filtration. Les collecteurs sont montes sur la paroi interne du tambour et sont fixes directement sur celle-ci en tant qu'elements faisant partie de la structure. De plus, chaque collecteur sert de reservoir pour le stockage de la liqueur de lavage.
PCT/US1979/000166 1978-03-15 1979-03-13 Filtre a tambour rotatif et sa methode de nettoyage Ceased WO1979000765A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US88683678A 1978-03-15 1978-03-15
US05/886,837 US4157301A (en) 1978-03-15 1978-03-15 Drum construction for rotary drum filter
US886836 1978-03-15

Publications (1)

Publication Number Publication Date
WO1979000765A1 true WO1979000765A1 (fr) 1979-10-04

Family

ID=27128813

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1979/000166 Ceased WO1979000765A1 (fr) 1978-03-15 1979-03-13 Filtre a tambour rotatif et sa methode de nettoyage

Country Status (8)

Country Link
AU (1) AU4510679A (fr)
CA (1) CA1110552A (fr)
ES (1) ES478684A1 (fr)
FR (1) FR2419746A1 (fr)
IT (1) IT1192640B (fr)
MX (1) MX147795A (fr)
NL (1) NL7901975A (fr)
WO (1) WO1979000765A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1993013262A1 (fr) * 1991-12-20 1993-07-08 The Black Clawson Company Pile laveuse de pate a papier ou appareil epaississeur fonctionnant par gravite

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2289762A (en) * 1939-05-08 1942-07-14 Oliver United Filters Inc Method and apparatus for filtering
US3027011A (en) * 1958-01-06 1962-03-27 Whiting Corp Pulp washer and filter
US3262575A (en) * 1963-08-08 1966-07-26 Dorr Oliver Inc Rotary drum filters
US3627139A (en) * 1970-06-22 1971-12-14 Nikolai Alexandrovich Burtsev Continuous drum vacuum filter
US3630380A (en) * 1969-08-28 1971-12-28 Dorr Oliver Inc Rotary vacuum drum filters

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2289762A (en) * 1939-05-08 1942-07-14 Oliver United Filters Inc Method and apparatus for filtering
US3027011A (en) * 1958-01-06 1962-03-27 Whiting Corp Pulp washer and filter
US3262575A (en) * 1963-08-08 1966-07-26 Dorr Oliver Inc Rotary drum filters
US3630380A (en) * 1969-08-28 1971-12-28 Dorr Oliver Inc Rotary vacuum drum filters
US3627139A (en) * 1970-06-22 1971-12-14 Nikolai Alexandrovich Burtsev Continuous drum vacuum filter

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1993013262A1 (fr) * 1991-12-20 1993-07-08 The Black Clawson Company Pile laveuse de pate a papier ou appareil epaississeur fonctionnant par gravite
US5266168A (en) * 1991-12-20 1993-11-30 The Black Clawson Company Gravity type pulp washer or thickener with rotating disrupters

Also Published As

Publication number Publication date
ES478684A1 (es) 1980-01-01
MX147795A (es) 1983-01-12
IT7921027A0 (it) 1979-03-15
NL7901975A (nl) 1979-09-18
CA1110552A (fr) 1981-10-13
FR2419746A1 (fr) 1979-10-12
IT1192640B (it) 1988-04-27
AU4510679A (en) 1979-09-20

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