CA1303423C - Limp, porous membrane for a fluidized outlet - Google Patents

Limp, porous membrane for a fluidized outlet

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Publication number
CA1303423C
CA1303423C CA000572017A CA572017A CA1303423C CA 1303423 C CA1303423 C CA 1303423C CA 000572017 A CA000572017 A CA 000572017A CA 572017 A CA572017 A CA 572017A CA 1303423 C CA1303423 C CA 1303423C
Authority
CA
Canada
Prior art keywords
outlet
membrane
walls
limp
fluidized
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.)
Expired - Fee Related
Application number
CA000572017A
Other languages
French (fr)
Inventor
Perry D. Fix
William B. Rogers
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.)
ACF Industries Inc
Original Assignee
ACF Industries Inc
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
Application filed by ACF Industries Inc filed Critical ACF Industries Inc
Priority to CA000572017A priority Critical patent/CA1303423C/en
Application granted granted Critical
Publication of CA1303423C publication Critical patent/CA1303423C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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  • Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
  • Filling Or Emptying Of Bunkers, Hoppers, And Tanks (AREA)

Abstract

Abstract of the Disclosure A limp, porous membrane of sheet (i.e., cloth) material for a fluidized outlet is disclosed. The outlet is in communication with a container, such as a hopper within a covered hopper railway car, containing a supply of particulate material for being fluidized and unloaded via the outlet. The outlet comprises an outlet housing, an outlet frame for securing the outlet housing to the hopper, an outlet opening, and outlet walls extending from the frame to the outlet opening. The membrane is secured to the outlet frame and to the outlet opening and is disposed generally on the inside faces of the outlet walls. A
manifold is provided for introducing a fluidizing fluid (e.g., air) under pressure between the outlet walls and the membrane such that the fluidizing fluid flows through the membrane thereby to fluidize the lading above the membrane. A stiffener extends from the outlet frame to the outlet opening for holding the limp membrane generally in face-to-face relation with the outlet wall in at least the area of this holder during fluidization of the lading.

Description

~L3~3~
~ck~round o~ the Invention _ __ _ _ __ __ _ _ This invention relates to a limp, porous membrane of sheet or cloth material or a 1uidized ou~le~. ~ore speciflcally, this invention relates to the ~luidized outlet Oe a coveeed hopper railway car.
Generally, when unloading a bulk pulverant, powdered, or particulate lading from a hopper, such as a hopper o~ a covered hopper cae, such ladings have a tendency to bridge and column inside the hopper. In order to continue the unloading, it is a common practice to vibrate or hammer on the outside of the hopper, thereby to dislodge the bridged and columned lading. It is also conventional to use probes inserted into the lading rrom above to break up the bridges and columns within the 1ading.
It has been known that by using a 1uidized outlet built into the bottom o the hopper, fluidizing fluid (e.g., air under relatively low pressure, S-15 psi) flowing through a fluidizing, porous membrane and into the powdered or particulate lading 1n contact w1th the membrane would cause the lading to ~e 1uid zed so that the lading would flow as freely as a liq~id. This resulted in faster and much more eficient unloading of the railway hopper car.
As shown in the co-assigned U.S. Patents 4,280,706 and 4,568,244, i.ssued in April, 1981 and April, 1986, respectively, prior art fluidizing membranes conventionally comprised a porous screen or the like made of .fine mesh stainless steel. However, while stainless steel fluidizing membranes were relatively impervious to moisture pick-up, could be readily cleaned, and weee long-lasting, they were relatively expensive, both to install and to replace if necessary. ~n a larger size o ~3~3~3 outlets where the outlet had both side and end walls converging inwardly and downwardly from the centraL lower outlet opening, the stainless steel membrane was often formed in one piece so as to be disposed on the inside faces of the end and side walls.
During unloading, particularly upon exhausting of all or substantially all of the lading from within the hopper, the stainless steel mesh, which was relatively rigid, had suficient force to withstand the static air pressure behind the porous membrane in the outlet walls without damage to the porous membrane.
It has long been recognized that limp fabLic membranes could be used in place of the stainless steel membranes with large attendant cost savings. However, cloth membranes were rela~ively difficult to seal at ~he connection o~ the cloth membrane and the outlet frame and to the outlet opening at the bottom proximate the outlet opening. In addition, cloth membranes o~tentimes did not have sufficient strength to withstand the static air pressure therebehind when the lading was nearly withdrawn from the outlet. It will be appreciated that the static air pressure would tend to "balloon" the membrane matexial away from the walls of the outlet when the hopper was substantially free o~ the lading thus putting undue tearing ~orces on the membrane where it joined the outlet frame and the bottom outlet As a conse~uence, oftentimes, fabric membranes were only used in relatively small panels in which the cloth membrane could be secured around its periphery to a rigid metal frame, such as shown in the co-assigned U.S. patent 4,280,706.

~3~3~ 3 Thus, there has been a long-standing need for a relatively inexpensive, limp cloth fluidizing membrane which could be used on large fluidized outlet walls and surfaces which did not experience undue ~ballooning~ when pressurized such that the membrane would remain attached to the outlet, both at the outlet frame and at the outlet opening.

Summar~ of the Invention Thus, according to the present invention, there is provided a limp, porous membrane o~ flexible sheet material for use with a fluidized outlet, said outlet being in communi.cation with a container, such as a hopper, containing a supply of a particulate lading Eor being fluidized and unloaded via said outlet. The outlet comprises an outlet housing having an outlet frame for securing said outlet to said hopper, an outlet opening, and outlet walls extending from said frame to said outlet opening. The membrane is secured to said outlet frame and to said outlet opening and is disposed generally on the inside face of said outlet walls. Means are provided for introducing fluidized fluid undar pressure between said outlet walls and said membrane such that fluid flows through said membrane so as to fluidize said lading. Means are also provided, carried by said membrane extending generally from said outlet ~rame to said outlet opening, for holding said limp membrane generally in face-to-face relation with said outlet walls at least in the areas of said holding means during fluidization of said lading.
Notable amongst the advantages to be realized by the present invention are the following:
The use of limp, porous (for example, cloth) membranes which will hold their shape, in place of more expensive stainless steel membranefi for use with a wide variety of pulverant, particulate ladings.
The use of limp porous membranes as recited which will resist "ballooning" forces when exhaustion of the lading from ~3~313~L23 within the hopper is near complete, and when fluidizing fluid remains connected to the fluidization system.
The use of a limp fluidizing membrane which may be readily incorporated in a number of outlets of various size6, which is of cugged construction, which is reliable in operation, which may be readily cleaned, and which has a long service life~
The invention will now be described further by way of example only and with reference to the accompanying drawings.

Brief Description of_~he Drawinqs FIG. 1 is an exploded view of a fluidized outlet for a railway hopper car. showing a membrane assembly of the pre6ent invention;
FIG. 2 is a top plan view of the membrane assembly;
FIG. 3 is a side elevational view of the membrane assembly;

~L36~3~;~3 FIG. 4 is a cross sectional view, taken along line 4--4 of FIG, 2, illustrating, on an enlarged ssale, means carried by the membrane assembly for holding the membrane assembly in place relative to the walls of the outlet;
FI~. S is a vertical cross sectional view of an outlet boot of the membrane assembly, taken along line S--5 of FIG. 2;
and FIG 6 is a cross setional view, taken along line 6--6 of FIG. 2, illustrating the gasket on an enlarged scale utilized to seal the porous membrane between the outlet frame and the hopper frame.
Corresponding reference characters indicate corresponding parts throughout the several views of the drawing.
Description of a Preferred Embodiment Referring now to the drawings, and particularly to FIG.
1, a pneumatic, fluidized outlet lS indicated in its entirety by reference charac~er 1. This outlet 1 is adapted to be bolted to the lo~er portion of a hopper ~not s;hown), such as a hopper of a covered hopper railway car utilized ~o transport a wide variety o~ bulk particulate, powdered, granular, or other pu~verant ladings. It will be appreciated that within the broader aspects Q~ the present invention, the term "particulate" is used generally to refer to any powdered, granular, or other dry, ~lowable lad ing .
More specifically, outlet 1 is shown to comprise an outlek housing 3, having an outlet frame 5 at its upper end, and an outlet opening 7 at its lower center portion. The outlet further has a plurality of outlet end and side walls 9 and 10, respectively, sloping inwardly and downwardly from outlet frame 5 toward outlet opening 7, As indicated at 11, so-called valleys are formed at the intersections between the side and end walls.

~3~3~L23 In accordance with this invention, a fluidizing membrane assembly, as generally indicated at 13, is provided on the inside ~aces of the outlet walls 9 and 10. Means 15, reerred to as a fluidizing air manifold, is provided for introducing a fluidizing medium (i.e., air under pressure) between the outlet walls 9 and 10 and fluidizing membrane 13, such that the fluidizing medium will ~low through the porous membrane and tend to 1uidize the lading in close proximity to the membrane, such that the ladiny will flow, as a liquid, downwardly over the inner surfaces of the membrane toward outlet opening 7, thus greatly facilitating the unloading of pulverant material from within the hopper. A
fluidizing air distribution manifold 17 may optionally be provided between outlet walls 9 and 10 and fluidizing membrane 13 so as to be in communication with means lS so as to distribute the 1uidized medium between the o~tlet walls and the membrane assembly 13.
As indicated at 19, an outlet manifold is secured to the bottom portion of the outlet walls so as to be in communication with outlet opening 7 such that the fluidized lading may be removed from the outlet in any conventional manner, such as by pneumatic ~onveying, or the like. It is intended that outlet 1 is a pressure diferential outlet such ~hat elevated pressure of a predetermined level (e~g., S psi) may be exerted upon and maintained wi~hin the hopper o~ the hopper car. Fluidizing air int~oduced into outlet 1 via fluidizing means 15 and manifold 17 will, o~ necessity, be of a somewhat higher pressure level so that the ~luidizing air will ~low freely through membrane 3 and ~luidize the lading in close proximity to the membrane, Upon the ~3~3~4~

lading being fluidized and flowing downwardly for unloading via outlet opening 7, the elevated pressure within the hopper forces the fluidi~ing lading out of manifold lg and into a conduit (not shown) ~or pneumatically conveying the lading away from the outlet. An outlet control valve 21 is provided for regulating the flow of lading f~om the outlet. A fluidizing air bypass valve 23 is provided between fluidizing air manifold 15 and outlet manifold 19 such that the amount of fluidizing air admitted into distribution manifold 17 for fLuidizing the lading may also be regulated.
Refe~ring now to FIGS. 2~6, the 1uidizing membrane assembly 13 is shown to comprise a gasket 25 around its upper edge with a cloth membrane, as indicated at 27, secured lstitched) to the gasket, as indicated at 28 (see FIG. 6).
Gasket 25 comprises upper and lowe~ gasket members 2~ with an elastomeric s~rip 31 therebetween. Securement bolt holes 33 are provided at desired spaced locations (as shown in FIG. 2) such that the gasket may be bolted between outlet frame 5 and a corresponding hopper frame (not shown). For example, the gasket material may be constructed in accordance with the gasket disclosed and claimed in the co-assigned U.S. patent 4,428,585 Membrane assembly 13 further comprises generally trapezoidal side panels 35a, 35b disposed on opposite sides o the membrane, and end panels 37a, 37b at opposite ends of the membrane assembly. The membrane side and end panels are disposed to be generally in face-to-face contact with the inside respective faces of outlet side and end walls 9 and 10. Further, ~3~4~3 the membrane side and end panels are joined together along membrane panel intersections, as generally indicated a~ 39, which in the outlet frame in ~IG. 1, tend to overlie valleys 11 between outlet walls 9 and 10. A boot assembly 41 is secured to the lower margins of the side and end panels, in the manner illustrated in FIG. 5, such that the membrane assembly may be rigidly connected to outlet housing 3 surrounding the outlet opening 7. The boot includes a gasket 43 (as best shown in FIG.
S) at the lower margin thereof for being rigidly secured to the lower portion of the outlet housing.
In accordance with this invention, a membrane stiffener, as generally indicated at 4S, is carried by the permeable membrane generally at the locations of the intersections 3~ so as to support the membrane side and end panels between gasket 25 and boot 41 thereby to prevent undue "ballooning" of the side and end panels during fluidization, and more particularly when the lading is substantially unloaded therefrom and when fluidizing air continues to enter via the fluidizlng air inlet means 15. More specifically, each membrane stiffener, as shown in FIG. 4, comprises an elongate, rigid rod 47 of suitable metal (e.g., s~ainless steel or the like) which is held captiva within overlapping panel portions 49 of the side and end panels 35a, 35b anad 37a, 37b, respectively, which are stitched together along lines of stiching 51.
In this manner, with fluidizing membrane assembly 13 disposed on the inside faces of outlet housing walls 9 and 10, with gasket 25 secured between outlet frame 5 and the hopper frame (not shown), and with boot 41 secured to the bottom of the ~3~3~;~3 outlet frame, membrane stiffeners 45, and par~icularl.y rods 47, hold the intersecting edges of the side panels 35a, 35b and the end panels 37a, 37b in close proximity to the inner faces o the outlet walls in the general proximity o~ valleys lL without placing undue stresses or tear-out forces on the fabric membrane adjacent gasket 25 or boot 41. However, those skilled in the art will appreciate that the membrane stiffeners 45 of the present invention do permit a limited amount of "ballooning" action of the flexible membrane between the stiffeners which aids in clean out of the outlet by forcing any residual lading clear of the membrane and to fall into the outlet opening.
In this manner, a porous, limp cloth membrane can be utilized on large size outlets in place of rigid and more expensive stainless steel mesh outlets, without the necessity of the outlet membLane being divided lnto small panels and secured around all of the edges to the outiet frame. AdditionalLyl a more complete clean-out of the paLticulate Lading materiaL is possible.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

Claims (5)

1. A limp, porous membrane of flexible sheet material for use with a fluidized outlet, said outlet being in communication with a container containing a supply of a particulate lading for being fluidized and unloaded via said outlet, said outlet comprising an outlet housing having an outlet frame for securing said outlet to said hopper, an outlet opening, and intersecting outlet walls extending downwardly from said frame to said outlet opening and having valleys between adjacent outlet walls, said membrane being secured to said outlet frame and to said outlet opening and being disposed generally on the inside face of said outlet walls and supported thereby, means for introducing fluidizing fluid under pressure between said outlet walls and said membrane such that fluid flows through said membrane so as to fluidize said lading, and stiffener means carried by said membrane extending generally from said outlet frame to said outlet opening for holding said limp membrane generally in face-to-face relation with said outlet walls and in close proximity to the valleys between adjacent outlet walls during fluidization of said lading.
2. A limp membrane for a fluidized outlet as set forth in claim 1, wherein said membrane comprises a plurality of panels which are joined to one another in juncture areas which are in general alignment with the valleys between adjacent outlet walls, and said stiffener means comprise a plurality of stiffeners engaging said panels in the areas of juncture therebetween to hold same in close proximity to the valleys between adjacent outlet walls.
3. A limp membrane for a fluidized outlet as set forth in claim 2, wherein said stiffeners each comprise a metal rod held captive by a portion of said membrane stitched on itself.
4. A limp membrane for a fluidized outlet as set forth in claim 3 having a gasket around its upper edge for being sealed with respect to said outlet frame and a boot at its lower end, said boot being securable to said outlet opening, said stiffeners extending substantially from said gasket to said boot.
5. A limp membrane for a fluidized outlet as set forth in claim 1, 2, 3 or 4, wherein said container is a hopper.
CA000572017A 1988-07-14 1988-07-14 Limp, porous membrane for a fluidized outlet Expired - Fee Related CA1303423C (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA000572017A CA1303423C (en) 1988-07-14 1988-07-14 Limp, porous membrane for a fluidized outlet

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA000572017A CA1303423C (en) 1988-07-14 1988-07-14 Limp, porous membrane for a fluidized outlet

Publications (1)

Publication Number Publication Date
CA1303423C true CA1303423C (en) 1992-06-16

Family

ID=4138377

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000572017A Expired - Fee Related CA1303423C (en) 1988-07-14 1988-07-14 Limp, porous membrane for a fluidized outlet

Country Status (1)

Country Link
CA (1) CA1303423C (en)

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