US3241678A - Fibrous structures - Google Patents

Description

March 22, 1966 Filed Dec. 13. 1961 Fig.1

5 Sheets-Sheet 1 lNVENTOR ART/ UR C. WROTNO WSK/ BY Fm v 222 ATTO R N Y5 March 22, 1966 A. c. WROTNOWSKI 3,241,673 I FIBROUS STRUCTURES Filed Dec. 15, 1961 3 Sheets-Sheet z INVENTOR ARTHUR C. WROTNOWSKI BY 7? a, ORNZYS ATT March 22, 1966 A. c. WROTNOWSKI 3,241,678

FIBROUS STRUCTURES Filed Dec. 13. 1961 5 Sheets-Sheet 3 INVENTOR. ARTHUR C. WROT/VOWSK/ Wm M W ATTO AE'YS United States Patent 3,241,678 FIBROUS STRUCTURES Arthur C. Wrotnowski, Greenwich, Conn., assignor to American Felt Company, Glenville, Conm, a corporation of Massachusetts Filed Dec. 13, 1961, Ser. No. 159,023 3 Claims. (Cl. 210231) This is a continuation-in-part of application Serial No. 724,973, filed March 31, 1958, now abandoned, in the name of Arthur C. Wrotnowski.

This invention relates to filter elements of the nonwoven non-metallic type, and particularly to a unitary fibrous filter plate for use in a plate and frame type filter.

Plate and frame type filters are Well known in the art, an example thereof being shown in US. Patent No. 891,393. Such arrangements normally have frames which are recessed, said frames having transverse passages extending from one face to the other. The transverse passages provide a fluid path along the filter in cooperation with similar transverse passages in adjoining plates and frames extending the length of the filter. The frames also have passages extending from said recess thereof to the transverse inlet passage thereof. In prior practice, the plate means have been composed of a plurality of elements, said plate means being located in the press between pairs of the aforementioned frames. Each of the prior plate arrangements has been composed of a heavy separating member having a waffle or frustum design dressed with woven filter cloth on either side thereof. The woven cloth has been carried in various manners on the face of the plate. In many instances, the separating plate has been of cast iron or heavy material. The plate arrangements have been thick with resultant undesirable filter length and have been awkward to handle and replace. Furthermore, because the separating plate is impervious, any difference of pressure between the sides thereof due, for example, to the filter cloth on one side being clogged, may cause breakage of the plate.

One of the objects of the present invention is to provide a fibrous filter plate element which is unitary, easy to handle and is economical to make and use.

Another of the objects of the invention is to provide a unitary filter plate combination having improved filtering characteristics.

Another of the objects of the invention is to provide a non-metallic plate assembly.

In one aspect of the invention, a plate assembly may comprise an internal drainage member having drainage channels therein and having an outlet zone means, the internal drainage member preferably being made of a suitable felt such as a synthetic fiber felt. Filter plate felt fabric or media members can be cut'to the desired shape and placed on either side of the drainage member. Preferably, but not necessarily, a separating or spacer means is used between said two outside filter media face members, said separating means having a cutout portion or recess including an outlet zone to receive the internal drainage member and its drainage zone or appended area. The complete assembly can be joined around its edge zone by pressing and sealing, such as by fusing or by a suitable adhesive, a restricted peripheral zone thereof, which zone also will provide gasketing surfaces on either side of the laminated plate against which adjoining frame members can be held in abutting and sealing relationship. The joining can be by fusing or by using a suitable adhesive. In one form, the side plates and gasketing area are substantially flat or in a single plane. The drainage member preferably may be of mechanically interlocked felt which is formed by subjecting the fiber batt to a needling operation. The plates and frames have passages extending therethrough or across their faces which register when in assembled relation to form outlet and inlet passages for the fluid.

In another aspect of the invention, a plate filter assembly may include a central impervious plate element having a plurality of transverse through passages adjacent the corners thereof. Frame members may be located on each side of the central plate and may surround drainage elements in the form of grid, lattice or perforated members, and one of the through passages of the central plate may communicate with the spaces within said frame members that are occupied by the grid or lattice members. Each frame member may be covered with a sheet of filter media, retaining the grid members in place, and the entire assembly may be sealed together forming a unitary assembly.

These and other objects, advantages and features of the invention will become apparent from the following description and drawings which are merely exemplary.

In the drawings:

FIG. 1 is a broken view of one form of frame and filter press with which the present invention can be used.

FIG. 2 is an exploded view showing the various ele ments before assembly of a plate for use in FIG. 1.

FIG. 3 illustrates the plate of FIG. 2 in an assembled relationship.

FIG. 4 is a sectional view looking in the direction of line 4-4 of FIG. 3.

FIG. 5 is a view of a plate with an open discharge.

FIG. 6 is an exploded perspective view of a modified form of filter plate.

The frame and filter press arrangement can have rigid end members 10, 11 (FIG. 1), said end members being held in assembled relation in any suitable manner, such as by rod or strut means 12 on either side of the plates and frames. Frame members 13 are located between plate members 14, said frame members having hollow or recessed interior portions 15 with passageways 16 connecting the interior 15 with transverse inlet passages 17, said transverse passages extending laterally across the frame between opposite faces of the frame. The joined inlet passages in the various elements register and are connected with supply or inlet pipe 18. Similar outlet passages not connected to the recess 15 are also provided in the usual manner.

This invention particularly and specifically relates to the unitary construction of the fibrous filter plate members 14. The fibrous filter plate member has encasing or enclosing means 19, 19 of a suitable filter media, preferably synthetic fiber felt. This may be a bonded felt, such being felt which is composed of fibers, some of which have binder properties, and which have been subjected to heat and pressure. The fibers may be thermoplastic or may have any desired cohesive or adhesive properties.

The internal drainage member 20 can be composed of a material having drainage channels such as a coarse felt, preferably synthetic fiber mechanically interlocked felt. The drainage member is shaped so that it has a drainage zone or means 21 extending from an edge or appended thereto. Usually, a transverse aperture 22 is provided therein extending across the member and in registration with the outlet passages 30 and 26.

Spacer boarder means or frame means 23 can be of a suitable plastic material having an opening or pocket 24 extending therethrough and including a drainage zone or transverse through passage 25 formed therein, said drainage zone being coextensive with and being arranged to receive drainage means 21 of drainage member 20. The spacer means 23 also can be of the same felt as the face plates and there may be a plurality thereof. Outlet passage 26 is arranged so as to cooperate with passages 25, 22 in frame 23 and drainage member 20; and inlet passage 27 in means 19 and frame 23 are aligned.

may'be die cut to shape.

in abutting relationship with the frames of the press.

As an example, the filter media 19, 19 may be made of a bonded felt 0.0100.100 in thickness, such a felt having binder fiber therein so that part of the fibers become bonded by cohesion or adhesion under heat. The spacer plate 23 can be made, for example, of material 43 ,to A" in thickness and the drainage member a similar thickness.

The spacer plate can be made of bonded felt or some suitable plastic. The drainage member can be made of a synthetic fiber mechanically interlocked felt. The various materials can be die cut to shape and then laminated in a hot compression step on a fiat bed press.

For example, the heat may be in the range of 200 to 700 F. and the pressure 25 to 1000 p.s.i. The finished thickness of such a plate will be in the range of to /2. The press elements are arranged so that only the peripheral zones will be joined and not the drainage area or the. outlet zone of the drainage member.

a The laminating operation will serve to mount the filter media in the assembly, stiffen the filter plate assembly and develop the bearing gasketing surface.

As a result of the thinner plate, a considerably larger number of plates for filtering will become available in a frame and filter press of a given length. Also, there will be no danger of a cast iron separator plate breaking because of unequal pressure on the two sides of the plate. Further, the plates will be non-metallic so that they will have a chemical, electrolytic and biological stability.

Also, the plate can be made one-tenth the weight of a conventional plate.

3 Various types of synthetic fibers or combination thereof can be used. As an example, linear polyamide fibers known as nylon, acrylic fibers sold under the name .Orlon and polyester fibers sold under the name Dacron. Other fibers includes polyethylene and Vinyon, a copolymer of vinyl chloride and vinyl acetate. One example of a suitable bonded felt is one composed of 1090% Vinyon and 90-10% Dacron. By using non-woven felt, the defect of blinding due to apparent collection of particles at thread intersections is eliminated. A further form is illustrated in FIG. 5 wherein an open drainage means A having valve 30B is suitably fastened to the assembly 31, such being usable as is well known in the art to provide alternate outlets. One of the outlets can have back wash water introduced therethrough when desired. Assembly 31 may be similar to that describe for FIGS. 2 and 3.

Referring to FIG. 6, the filter plate 14 (FIG. 1) may be replaced by a filter plate assembly comprising a central .plate 32 having transverse through holes 33, 34, 35, 36 and 37. This plate may be made from a plastic or hard pressed bonded fiber that is coated on both sides with a polyethylene or other heat sealing film,'after which it By bonded fiber is meant, besides others, a mixture of plastic fibers having different molecular weights and melting points so that heating to a predetermined temperature under a predetermined pressure causes the fibers of lower melting temperature to become tacky, bonding the fibers of higher melting temperature into a semisolid mass. Frame members 38 made from a plastic material may be placed on each side of the central plate 32 and the assembly may be heat sealed or otherwise integrally joined. This provides pockets 39 and 40 on each side of central plate 32 for the reception of drainage members 41 and 42, which latter may be in the form of a lattice. The lattice drainage members 41 and 42 may be made from stainless steel or the like, but

preferably are molded from aplastic such as 30% poly- 4 propylene and 70% of a lower melting thermoplastic material.

A sheet 43 of filtering media may be heat sealed to the borders of the frames 38 to complete the filter plate assembly. Sheets 43 may be made from felted polypropylene bonded fibers, one example of which may be 45% polypropylene fibers and 55% polypropylene binder. The central plate 32 may also be made from this mixture.

The through passage 33 may include slots 44 that form drainage passages leading from the pockets 39 and 40 to the through hole 33. The hole 33 is aligned with corresponding holes in elements 38 and 43; however, such corresponding holes do not include slots 44. The holes 34, 35, 36 and 37 do not communicate with the pockets 39.and 40, but are aligned with corresponding holes in the elements 38 and 43.

When the filter press plate assembly of FIG. 6 is substituted for fiber plates 14 of FIG. 1, the holes 33 communicate with the outlet line; the holes 34 communicate with the inlet line 18; and the holes 35 may be employed with a line (not shown) that equalizes the pressure of fiber, spaced transverse passage means arranged in and extending through said plate member adjacent the periphery thereof, a frame member on each side of said plate member, generally corresponding in shape with said plate member, each frame member being of plastic bonded fiber and having an inner periphery defining a pocket therein, spaced transverse through passage means in said frame members in alignment with said passage means in said plate member, plastic lattice drainage members removably arranged in said pockets and being of substantially the same thickness as said frame members and being coextensive with said pockets, said lattice members being separated from each other and said central plate, and fiber filter sheets arranged on one side of and attached to said frame members, said filter sheets having spaced transverse through passage means therein in alignment with said through passage means in said frame members and said central plate member.

2. A filter plate assembly according to claim 1, wherein said' frame members and said filter sheets are integrally bonded to each other and to said central plate member.

3. A filter plate assembly according to claim 1, wherein said central plate is of hard pressed bonded fiber coated on both sides with a heat sealing film.

References Cited by the Examiner UNITED STATES PATENTS 393,633 .11/1888 Enzinger 2l0228 1,282,414 10/1918 Hagstrom 21023l 1,308,438 7/1919 Miller 210-231 1 2,006,131 6/1935 Durant 210- 226 2,122,259 6/1938 McKenna 210-23l 2,186,501 1/1940 Seligman et al. 210228 2,594,518 4/1952 Teale 210-231 2,788,901 4/1957 Boeddinghaus et a1. 210-486 2,830,359 4/1958 Reinshagen 29-l63.5 3,007,238 11/1961 Pail 29-1635 OTHER REFERENCES Dupont Industrial Coated Fabrics 194, Scientific American, No. 3, page 1, March 1956.

REUBEN FRIEDMAN, Primary Examiner. HERBERT L. MARTIN, Examiner.

Claims (1)

1. A FILTER PLATE ASSEMBLY FOR A FILTER PRESS COMPRISING IN COMBINATION, A CENTRAL PLATE MEMBER OF PLASTIC BONDED FIBER, SPACED TRANSVERSE PASSAGE MEANS ARRANGED IN AND EXTENDING THROUGH SAID PLATE MEMBER ADJACENT THE PERIPHERY THEREOF, A FRAME MEMBER ON EACH SIDE OF SAID PLATE MEMBER, GENERALLY CORRESPONDING IN SHAPE WITH SAID PLATE MEMBER, EACH FRAME MEMBER BEING OF PLASTIC BONDED FIBER AND HAVING AN INNER PERIPHERY DEFINING A POCKET THEREIN, SPACED TRANSVERSE THROUGH PASSAGE MEANS IN SAID FRAME MEMBERS IN ALIGNMENT WITH SAID PASSAGE MEANS IN SAID PLATE MEMBER, PLASTIC LATTICE DRAINAGE MEMBERS REMOVALBLY ARRANGED IN SAID POCKETS AND BEING OF SUBSTANTIALLY THE SAME THICKNESS AS SAID FRAME MEMBERS AND BEING COEXTENSIVE WITH SAID POCKETS, SAID LATTICE MEMBERS BEING SEPARATED FROM EACH OTHER AND SAID CENTRAL PLATE, AND FIBER FILTER SHEETS ARRANGED ON ONE SIDE OF AND ATTACHED TO SAID FRAME MEMBERS, SAID FILTERS SHEETS HAVING SPACED TRANSVERSE THROUGH PASSAGE MEANS THEREIN IN ALIGNMENT WITH SAID THROUGH PASSAGE MEANS IN SAID FRAME MEMBERS AND SAID CENTRAL PLATE MEMBER.

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