US3679271A - Support for a fluidized bed - Google Patents

Abstract

This invention relates to a support for a fluidized bed. The support consists of a perforated metal base, a wire screen adjacent the base and a mat of bonded metal fiber adjacent the screen.

Description

United States Patent Clark et al. 1 51 July 25, 1972 54] SUPPORT FOR A FLUIDIZED BED 2,968,405 l/l96l 72 Inventors: Raymond c. Clark; Donn G. Ziebell, both '3 "3 ofOrange Conn. 18 12/1 41 3,026,609 3/1962 [73] Assignee: Brunswick Corporation, Chicago, Ill. 3,023,906 3/1962 2,946,450 7/1960 22 Flled. Nov. 19,1969 3,069,017 12/1962 21 Appl. No.: 878,103 2,837,032 6/1958 Horsting, Sr ..210/510 52 U.S. Cl.....- ..302 45, 29 1823, 222 195 "7" f"-- Quarfmh r 51 Int. Cl ..B65g 53 34 48mm" Hammer-B- [58] Field of Search" ..210/496, 510'; 29/1823; Manley-Donald Sheldon p n 0.

75 010. 1, 200; 209/4 6; 222 195; 302/45, 54 flelmovlcs and wllllam Lawler [56] References Cite i ABSTRACT UNITED STATES PATENTS This invention relates to a support for a fluidized bed. The

1 support consists of a perforated metal base, a wire screen ad- 3,379,345 4/1968 Gehrung 222/195 jacem the base and a mat f bondedme-ta] fib adjacent the 1,461,647 7 1923 Bookwalter.. .....209/486 5mm 923,917 6/1909 Williams ..209/486 v 3,092,58l 6/1963 Jaffee ..2,l0/5l0 lClaim, 2Drawing Figures PATENTEDJUL25 I972 RAYMOND C. CLARK DONN G ZIEBE IN NTORS ATTORNEY SUPPORT FOR A FLUIDIZED BED BACKGROUND OF THE INVENTION Frequently it is desired to have structures through which fluid may be allowed to pass by diffusion through very small passageways. Thus, for example, in the transportation of finely divided particulate materials, such as cement, the vehicles in which such materials are transported frequently include structural members through which air may be blown for the purpose of fluidizing the particulate material and thereby facilitating its removal from the vehicle in question. Materials useful in such applications are shown, for example, in U.'S. Pat. No. 3,237,812. Typically, such structures have included a constituent member for diffusing air by channeling it through a multiplicity of relatively fine, tortuous, air passageways. However, such diffusion members typically are comparatively weak structurally and this deficiency tends to become more aggravated as the permeability of the diffusion member increases. Therefore, since the diffusion members must be strong enough to support the weight of the load being carried and, frequently, the weight of men who enter the vehicles for purposes of cleaning them, removing their contents, etc., it is a common practice to reinforce such diffusion members, for example, by use of perforated metal backing plates of sufficient thickness and land" area to insure adequate structural strength against breakage and other forms of damage during the aforesaid operations. However, the use of such structural reinforcements, involving, as it necessarily does, a substantial amount of land area through which fluid cannot pass, has heretofore resulted in shadowing effect on the diffusion member; that is, the land portions of the structural reinforcement tend to act as blocks to the passage of air through the diffusion member, resulting in a non-uniform distribution of diffused air or other fluid through the diffusion member. This lack of uniformity in diffusion is objectionable, for example, in aeration applications for several reasons, including lack of uniformity in the removal rate of the particulate material with which it is being used and the necessity for using higher air pressures in order to get the desired results.

Therefore, it is an object of the present invention to provide a structure through which fluid may be diffused substantially entirely uniformly throughout. 7

Another object of the present invention is to provide a fluid diffusing structure which is strong structurally but does not contain reinforcement shadows.

Still another object of this invention is to provide a fluid diffusion structure having improved strength characteristics.

SUMMARY OF THE INVENTION In accordance with the principles of the present invention, one embodiment thereof comprises a fluid diflusion member including a multiplicity of relatively small tortuous fluid passageways and a strength-reinforcing member in association therewith, with a plenum means interposed between the diffusion member and the reinforcing member such that fluid moving through passageways in the reinforcing member may diffuse laterally through the regions between the land" areas of the reinforcing member and the facing side of the diffusing member, with the result that fluid may pass through the fine tortuous passageways of the diffusion member substantially uniformly throughout.

BRIEF DESCRIPTION OF THE DRAWING invention, together with the accompanying drawing comprising;

FIG. I which is a cross-sectional view of one embodiment of this invention, and

FIG. 2 which is a cross-sectional view of a prior art struc- (life.

DESCRIPTION OF THE PREFERRED INVENTION Turning to FIG. I, there is shown a cross-section of one embodiment of the present invention. It comprises a base member 10 made from structurally strong material such as stainless steel having perforations 12 therein with "land" (or unperforated) portions 14 between the perforations. Although in FIG. 1 this member is illustrated as being a perforated sheet of metal, it will be apparent that a wide variety of other structures may also be used to equivalent efiect. Thus, for example, this member might be other than sheeblike in configuration and could, for example, be a lattice" or other relatively strong structure having a multiplicity of apertures therethrough of sufficient dimension to ensure an adequate flow of fluid therethrough consistent with the structural strength requirements of the finished structure. Of course, a wide variety of some different materials may be utilized to make the base member suitable to the requirements of the particular use and environment with which the structure is to be involved, such as plastic materials, or even wood, or other well-known materials.

Shown in FIG. 1 asresiding next adjacent to the structural strength member 10 is a plenum member 20. In FIG. 1, the plenum 20 is shown as a woven wire structure of comparatively open weave; that is, with distances between the constituent arrays of wires several times greater than the diameters of the individual constituent wires. Of course, such spacings may be adjusted more open or more closed, depending upon the proportions desired and in accordance with well-known engineering principles. Although the plenum means 20 is-illustrated in FIG. 1 as being made from woven wire, it will be obvious that a number of other materials might suitably be used to equivalent effect. Thus, a relatively open lattice, or an array of slat-like parallel members of non-woven configuration, as well as a wide variety of structures made from materials other than metals, such as plastics, natural materials, such as wood, and the like, might also be used. The important characteristic of the plenum member for purposes of the present invention is that it be of such a form and configuration as to permit the lateral diffusion of fluid passing through the apertures 12in the base member 10 into the regions 22 residing between the land areas 14 of the base member 10 and the facing portion of the difi'usion member 30, thereby negating the shadowing" effect that would otherwise occur. In effect, the interposition of the plenum produces a substantially uniform distribution of the fluidizing medium throughout the entire lower surface of the diflusion member which, in turn, ensures substantially uniform distillation through, and throughout the top surface of, the diffusion member.

This shadowing effect, which was a drawback of the prior art structures, is shown in FIG. 2 wherein is depicted a structural base member 50 comprising perforations 52 with land portions 54 interposed therebetween. Typically, such structures were adhered by means of epoxy or other adhesive compound 56 to one surface of a difiusion layer 60. However, when air or other fluid was pumped through the apertures 52 in the base member 50, the land portions 54 of the base member 50 had a blocking effect on the 'perviousness of the diffusion member 60, thereby tending to shadow the presence of the land portions .54 of the base member 50 through to thesurfaces of the diffusion member 60 in the form of domes" 58 through which no significant amount of fluid was diffused.

Referring again to FIG. 1, it will be readily apparent that this objection with the prior art structures, as illustrated in FIG. No. 2, is overcome by the present invention. FIG. 1 in addition to the elements previously described, also includes a diffusion member 30. This member comprises a multiplicity of very small tortuous paths through which air traveling through the apertures 12 in the base member 10, and vertically and laterally through the plenum member 20 may be distributed substantially uniformly throughout the lower surface of the diffusion member 30 and transmitted to the upper surface of the diffusion member 30 substantially uniformly throughout. This diffusion member may be produced from a wide variety of suitable materials, including bonded particulate materials; a term which is meant to include sinter-bonded ceramics, sinterbonded metal powders, sinter-bonded metal fibers, brazebonded metal powders or fibers, or any other form of integrated structure which includes a multiplicity of relatively small tortuous paths through which fluids may pass. Material particularly suited for this use are FELTMETAL fibermetal as manufactured by the Huyck Metals Company of 45 Woodmont Road, Milford, Connecticut, and those made in accordance with the teachings of Troy U.S. Pat. No. 3,127,668.

In the embodiment illustrated in FIG. 1, the constituent elements thereof comprising the base member 10, the plenum means 20, and the diffusion means 30, are in structural continuity with each other. By structural continuity is meant that the plenum means 20 which is interposed between the base member and the diffusion means 30, is in contact with both of them and that this contact may or may not be fixed" which includes bonding, for example, by means of sintering, adhesives, and/or brazing.

The embodiment of the present invention which is illustrated in FIG. No. 1 may be made, for example, by taking a screen reinforced fiber metal structure made in accordance with the teachings of Fisher, U.S. Pat. No. 3,437,457 and bonding same to a perforated metal backing sheet, provided of course that the screen reinforcement is sufficiently above the plane of the fiber metal with which it is associated to permit the screen to function as a plenum means for the lateral distribution of air or other fluids. It has also been found that the integrity of bonds between a woven plenum means and the other constituent members of the structure to which it is affixed can be enhanced by flattening the knuckles" of the woven structure to some extent, thereby providing a greater surface area for the adhesive, sinter, braze, or other bonds.

It will also be apparent from FIG. I that structures made in accordance with the present invention, particularly where the constituent members are affixed to each other, will be stronger than the structures of the prior art. This results from the fact of the diffusion member 30 and the strength providing base structure 10 having been physically separated from each other by the interposition of the plenum means 20 which effectively increases the vertical cross-sectional thickness of the structure. According to well-known engineering principles, this has a tendency to transfer any forces acting vertically to the plane of the structure to the strength member 10 where they appear as stress moments of force, to greater advantage than, for example, in structure such as that shown in FIG. 2 where there is no significant amount of spacing between the diffusing member and the base member 50.

Thus it will be apparent that through the practice of the present invention an improved structure may be produced for the diffusion of fluids therethrough which will not exhibit the objectionable shadow effects of the prior art devices, and in addition will be significantly stronger structurally than the prior art devices.

While I have shown and described only particular embodiments of the present invention, it will be obvious to those skilled in the art that the illustrations given and the terms used herein are by way of illustration and not of limitation, and that additional changes and modifications may be made without departing from the present invention in its broadest aspects. Therefore, it is the intention of the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the present invention.

What we claim as new and novel and desire to secure by Letters Patent of the United States is:

l. A support for a fluidized bed for transporting particulate material comprising:

a. a base made from perforated metal plate;

b. a metal wire screen diffuser adjacent the base and metallurgically bonded thereto; and c. a web of fiber metal ad acent the wire screen with the metal fibers of the web metallurgically bonded to each other and to the diffuser thereby providing a multiple path for fluid to pass therethrough wherein the diffuser distributes the flow of the fluid through the webs substantially uniformly.

Claims (1)

1. A support for a fluidized bed for transporting particulate material comprising: a. a base made from perforated metal plate; b. a metal wire screen diffuser adjacent the base and metallurgically bonded thereto; and c. a web of fiber metal adjacent the wire screen with the metal fibers of the web metallurgically bonded to each other and to the diffuser thereby providing a multiple path for fluid to pass therethrough wherein the diffuser distributes the flow of the fluid through the webs substantially uniformly.

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