US3791521A

US3791521A - Apparatus and method for continuous filtering

Info

Publication number: US3791521A
Application number: US00160746A
Authority: US
Inventors: W Eakins
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-09-09
Filing date: 1971-07-08
Publication date: 1974-02-12
Anticipated expiration: 1991-02-12
Also published as: US3615011A

Abstract

A traveling filter comprising a plurality of trays disposed to travel along a path, a plurality of frames adapted to travel along a second path and through a portion of said path mate with the trays to confine material thereon, and a plurality of conduit means adapted to travel along a third path and adapted to be advanced and retracted to establish communication with and discharge liquid from said trays.

Description

Unlted States Patent 1 1 1111 3,791,521 Eakins 1 Feb. 12, 1974 [54] APPARATUS AND METHOD FOR 3,138,088 6/1964 Foth 210/77 x CONTINUOUS FILTERING [76] Inventor: William S. Eakins, St. Andrews Ln.,

Glen Cove 11542 Primary ExaminerJohn Adee Attorney, Agent, or Firm-Kenyon & Kenyon Reilly [22] Filed: July 8, 19,71 Carr & Chapin [2]] Appl. No.: 160,746

Related US. Application Data Continuation-in-part of Ser. No. 845,984, July 30, 1969, Pat. No. 3,615,011, Continuation-impart of Ser/No. 613,691, Dec. 21, 1966, Pat. No. 3,460,674,

and a continuation-in-part of Ser. No. 578,361, Sept. 9, 1966, abandoned.

U.S. c1. 210/67, 210/393 1m. 01 B0ld 33/04 Field of Search 210/67, 391, 77, 328, 332,

References Cited UNITED STATES PATENTS 4/1963 Bounin 210/77 X 5 7 ABSTRACT A traveling filter comprising a: plurality of trays disposed to travel along a path, a plurality of frames adapted to travel along a second path and through a portion of said path mate with the trays to confine material thereon, and a plurality of conduit means adapted to travel along a third path and adapted to be advanced and retracted to establish communication with and discharge liquid from said trays.

6 Claims, 36 Drawing Figures PAIENTEI] FEB I 2 I974 saw 010% 17 I INVENTOR, MILL/4M 3 59km;

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PATENTEU FEB 12 1914 SHEET 170F W I N VEN TOR. Mum/1y S (Lyn V wwwzw Now Va i 1 APPARATUS AND FOR CONTINUOUS FILTERING This application is a continuation-in part of my copending application Sen No. 845,984 filed July 30, 1969, now US. Pat. No. 3,61'5,01l, issued Oct. 26, 1971, application Ser. No. 845,984 being a division of my then copending application filed Dec. 21, 1966 which issued as U.S. Pat. No. 3,460,674,the last menwhether it be induced by a pressure or a vacuum source, to 'thetr'aveling filter inorder to'treat the filter cake being accumulated upon the filter medium. During and after the deliveryof the material to be filtered to the'filter-medium which can'be'mountd upon a 'filter tray, it isgenerally necessary to apply a vacuum condition in'orderto'draw the liquid portion o f the'material through the filter medium and thereby separate and buildup a filter cake upon the medium. Since filtering apparatus commonlyemploys an'endless' belt of-appreciable length ofa plurality'of traveling filt'er trays and since itis u'suallynecessary to apply 'a'v'acuum or pressure condition*to the belt-or trays'over-an'eiitensive-period of travel, it"becornes difficult to provide the necessary equipment for subjecting the belt-oreach of the filter trays at least through Zpar t of their travel throughout the apparatus 'toa vacuum or .pressure condition without involving undue I complexity or shortened life forthe equipment.

1n the prior art, vacuum has been applied to an endless belt or to 'the separate trays of atravelingfilterby providing an'elongated suction-boxover whichthebelt or trays are advanced. Since his necessary-toforma seal between the bottom portion of l the belt orthe trays and the suctionbox, the resulting arrangement'is generally subject :to excessive leakage and a comparatively high rate of wear'between the fixed and stationary portions of the seal.

Another difficulty encountered with traveling filters has been that of obtaining an efficient, reliable and-durable arrangementfor removing thefilter cake after'its formationupon the filter medium. Wherever ap'lurality of continuously moving 'trays each having a-filt'er'medium are employed,difficultyis experienced in removingthe filter cake from the'tray sincethe caketends to cling firmly to'the tray and tothe 'filtermedium even though the tray is inverted after the formation of the filter cake. Where'eachtray'is providedwith side walls of sufficient'height to receiveand confine-a substantial quantity of material-to befiltered, the'side walls'ofthe tray present a greater area'to *whichthefilter-cake can cling and adhere during attemptsto remove'the cake from the tray. Attempts to insure removal of thecake from the tray by the applicationof'reverse'blasts' or jets of pressure fluid tothe filter cake have alsore'sulted in complicated designs which still I fail 'to provide for the simple and'reliable removal o'fthefilter'cake from "the filter medium withinthe tray.

It is therefore one of the objects'of the invention to provide a traveling filter to which flow of pressure or vacuum fluid can be applied without the need of continuously sliding seals or the like between the filter trays and the source of the fiow of pressured or vacuum fluid.

It is another object of the invention to provide a traveling filter in which the duration of the applying of pressure or vacuum to the filter trays-can be accurately controlled.

It is still another objectof the invention to provide a traveling filter in which pressure or vacuumcan be applied in a controlled manner with respect to each of the filter trays independently'of one another.

It is an additional object of the invention to provide atraveling'filter in'which fluid can be applied with respect to each tray individually 'even'though the filter travels over an appreciable distance.

It is a furthe'r object of the invention to provide a treveling filter=in which the construction of the trays is conditioned to facilitate the release and'theremoval of feed 'thetraysofa travlingfilter insequential-manner.

Itis another object of the invention to provide a traveling filter in which the filter medium of each of the trays can be operated-to facilitate the 'removalofthe filter cake therefrom. I

Inone of the-embodiments of f the invention the traveling filter includes 'a plurality of tray members each having afilter medium'which is-adated toreceive material tobefilteredi'Each ofthe'pluralityoftray members has a passage for passing a' flow' of fluid =with respect'to the -tray member. 'Means are provided "for conveying the plurality of tray members along a predetermined path. Atleas't one-conduita'dapted tobe connected to a device for'producing a flowof 'fiuid' is:provided. In addition, means are :provided for driving the conduit alongan additional-path adjacent'to-at least-a portion of the predeterminedpath of thetray membersMeans are also provided -for successively advancing and re- 'tracting'the-conduit with r'espec't'to its additional path as'the conduit'is driven in order suceessively 't o-enage and-disenage the conduit with respect to the passage' of the 'tray member as "the tray member I is conveyed.

An'advantage-of this arrangement is'thatthe operation of the conduit'canbe'conveniently'established at various locations alongthe predetermined path;of the tray-member since the conduit isdriven adjacentto the path of "the tray members'and sincethe conduit is advanced and-retracted with respect'to its own path. An additional advantageisthat it enablesa'flow of fluid to be controlled with'rsp'ectto each'individual tray member independently of theremaining 'traymembers. Another advantageis that-the 'advancing'an'd retracting of the conduit enables th'epassa'ge' of thetraymember'to be eng'agedand disengaged at various locations along 'its predetermined path or 'travel'without interfering with theconveying of the-tray member.

In another embodiment of the invention the tray members are provided with a cavity with whichthe passage is in communication and over which the filter medium is disposed. This construction enables the conduit to establish a flow of fluid with respect to the filter medium by way of the cavity.

In still another embodiment of the invention the filter medium of each of the plurality of tray members extends in a substantially horizontal plane throughout at least a portion of the predetermined path of the tray members in order to assist the accumulation of a filter cake upon the filter medium.

In an additional embodiment of the invention the conduit compries a tubular member which is adapted to successively engage and disengage the passage of the tray member in order to establish a flow of fluid with respect to the tray member.

In a further embodiment of the invention the traveling filter comprises a plurality of tray members each having a filter medium and means for conveying the tray members along a predetermined path. The filter further includes a plurality of frame members each having an opening adapted to mate in a facing relationship with the surface area of the filter medium. Means are provided for moving the plurality of frame members along another path extending at least in part adjacent to the predetermined path of the tray members in order successively to place and remove the opening of each of a portion of the plurality of frame members with respect to a conidtion of registry and substantial engagement with a different one of the tray members of a corresponding portion of the plurality of tray members.

An advantage of this arrangement is that the frame members are adapted to confine the material to be filtered upon the filter medium adjacent thereto. Subsequently, upon removal of the frame members from in registry and substantial engagement with the tray members, the removal of the filter cakes from the filter mediums is facilitated and made more positive.

In still a further embodiment of the invention the conveying means for the pluraity of tray members and the plurality of frame members each have upper and lower reaches with at least a portion of the lower reach of the frame members overlying and sufficiently adjacent to the upper reach of the tray members in order to enable the frame members to be placed in registry and substantial engagement with the tray'members.

In another embodiment of the invention the traveling filter includes means for delivering the material to be filtered through the openings of the frame members as .the frame members are moved along the lower reach of their conveying means.

In another embodiment, a hopper is positioned within the reach of the conveying means to be filled with feed material and intermittently pivotedin response to the presence of atray underneath to dump its contents into successive trays.

In a still further embodiment of the invention, the traveling filter has a take-up roller mounted adjacent a conveying means and a pair of scrapper blades. The take-up roller is provided with ports in the surface which communicate with a vacuum source to hold the cake material and the blades are arranged so that one scrapes a filter cake onto the roller and the other scrapes an upper layer of cake material from the roller at an advanced position.

Various other objects and advantages of the present invention will be readily apparent from the following detailed description when considered in connection with the accompanying drawings in which:

FIG. 1 is an elevational view of the traveling filter of the invention showing the lower reach of the conveyor of the frame members overlying and in substantial engagement with the upper reach of the conveyor of the tray members with means for successively advancing and retracting the conduits disposed adjacent to the upper reach of the conveyor for the tray members;

FIG. 2 is a fragmentary elevational view of the traveling filter showing the means for driving the conduits along an additional path adjacent to a portion of the predetermined path of the tray members;

FIG. 3 is a fragmentary plan view of the conveyor for the tray members showing the conduits and the means for driving the conduits along an additional path adjacent to a portion of the predetermined path of the conveyor of the tray members;

FIG. 4 is a plan view of a single one of the assemblies of conduits with the means for successively advancing and retracting the conduits as they are driven with respect to the conveyor for the tray members;

FIG. 5 is a vertical section view taken along the line 5-5 in FIG. 4 and showing the control valve arrangement for the flow of fluid through the conduits;

FIG. 6 is a vertical section view taken along the line 6-6 of FIG. 5 and showing the means for driving the conduits along an additional path adacent to the predetermined path of the tray members;

FIG. 7 is a perspective view of one of the plurality of tray members and one of the plurality of frame members in registry and substantially engaged with the tray member;

FIG. 8 is a vertical section view taken along a plane extending parallel to the line of travel of the tray membr and showing the cavity, the filter medium and the passage of the tray member;

FIG. 9 is a plan view of one of the tray members showing the filter medium overlying the plate of the tray member;

FIG. 10 is an elevational view of the end portion of a passage connected to a tray member showing the alternate titled portions which the passage can assume with respect to its support;

FIG. 11 is a vertical section view taken along the line 1l11 in FIG. 8'and showing the passage and the valve connected thereto for a tray member in alignment with the conduit;

FIG. 12 is a fragmentary vertical section view showing the opening of a conduit advancing into engagement with the valve of the passage leading to the tray member;

FIG. 13 is a fragmentary vertical section view showing the opening of the conduit fully engaged with the open valve of the passage leading to the tray member;

FIG. 14 is a fragmentary vertical section view of the conveyors for the frame members and the tray members and showing the filter cake being released from the tray member after removal of the frame member;

FIG. 15 is a fragmentary vertical section view showing a detachable filter medium for facilitating the removal of the filter cake;

FIG. 16 is a fragmentary vertical section-view showing means for assisting in the removal of the filter cake from the detachable filter medium;

Claims

2. An apparatus in accordance with claim 1 and further comprising an additional scraper blade disposed adjacent to the surface of said filter downstream of said roller, said additional scraper blade extending adjacent to the periphery of said roller and to a substantially close clearance with respect to the surface of said filter medium, whereby said additional scraper blade assists in the removal of the filter cake therefrom.
3. An apparatus in accordance with claim 1 and further comprising means for pivotally mounting said porous roller and said scraper, means for biasing said mounting means toward said filter medium, and means for engaging said mounting means to limit the clearance between said roller and said filter medium.
4. An apparatus in accordAnce with claim 1 in which said roller has end portions which extend axially beyond said additional filter medium on said roller and which have a slightly larger outside diameter than said additional filter medium, said end portions being adapted to engage said filter medium and said scraper blade establish a predetermined clearance between said filter medium and said additional filter medium and between said scraper blade and said additional filter medium.
5. Method of removing filter cake from the filter medium of a moving filter comprising positioning a porous roller having an additional filter medium disposed thereupon adjacent the path of travel of the filter medium of the moving filter and at a substantially close clearance therewith, rotating the roller with the peripheral movement thereof being in the same direction as the movement of the filter medium of the moving filter, inducing fluid flow through the additional filter medium into the porous roller, the fluid flow forming an additional filter cake upon the roller from the filter cake on the filter medium, the additional filter cake engaging the filter cake on the filter medium, and scraping a layer of filtered material from the roller to retain a uniform layer of additional filter cake thereon and to remove the remainder of filtered material therefrom, whereby the engagement of the additional filter cake on the roller with the filter cake on the filter medium enables the filter cake on the filter medium to be removed.
6. A method in accordance with claim 5 and further comprising the step of scraping the filter cake from the filter medium downstream of the roller and adjacent thereto.