US3302979A - Hopper structure - Google Patents

Description

1967 D. w. ROLLINS ETAL 3,

HOPPER STRUCTURE 7 Sheets-Sheet 1 Filed March 5, 1964 INVENTORS DALLAS W. ROLLINS WILLARD E. K MP AGENT 1967 D. w. ROLLINS ETAL 3,302,979

HOPPER STRUCTURE 'T Sheets-Sheet 2 Filed March 3, 1964 INVENTORS DALLAS W. ROLLINS WILLARD E. KEMP AGENT Feb. 7, 1967 Filed March 5, 1964 D. W. ROLLINS ETAL HOPPER STRUCTURE 7 Sheets-Sheet 5 INVENTORS DALLAS W. ROLLINS WILLARD E. KEMP 0/" 21 awn D. w. ROLLINS ETAL 3,302,979

Feb. 7, 1967 HOPPER STRUCTURE Filed March a, 1964 '7 Sheets-Sheet 4 INVENTORS DALLAS W. ROLLINS WlLLARD E KEMP AGENT 7 Sheets-Sheet 5 D. W. ROLLINS ETAL HOPPER STRUCTURE Feb. 7, 1967 Filed March 3, 1964 INVENTORS DALLAS W, ROLLINS BY WILLARD E. KEMP AGENT 1967 D. w. ROLLINS ETAL 3,302,979

HOPPER STRUCTURE '7 Sheets-Sheet 6 Filed March 5, 1964 INVENTOR. DALLAS W ROLLINS BY WILLARD E. KEMP gldl (7/ AGENT 1967 D. w. ROLLINS ETAL 3,302,979

HOPPER STRUCTURE Filed March 5, 1964 '7 Sheets-Sheet 7 INVENTORS DALLAS W. ROLLINS WILLARD E. KEMP United States l atent' 6 3,302,979 HOPPER STRUCTURE Dallas W.- Rollins, St. Charles, and Willard E. Kemp,

Bridgeton, Mo., assignors to ACF Industries, Incorporated, New York, N.Y., a corporation of New Jersey Filed Mar. 3, 1964, Ser. No. 349,538 11 Claims. (Cl. 302-52) This invention relates to a hopper structure for conveying and unloading bulk materials and more particularly to apparatus for transporting and conveying granular or pulverulent materials especially of the type transported in covered hopper railway cars.

In the unloading of granular or pulverulent materials, such as flour, sugar, cement, plastic pellets or powders, lime, and the like, a problem is presented because of the tendency of the particles to compact and adhere to each other. The movement of the railway car or other transport vehicle produces a jarring or vibratory eifect which further tends to compact the material as it is being transported from one location to another. I When the material is unloaded after being transported, the discharge of such material is not of a uniform flow in many instances due to compacted areas, particularly in corners, and the arching or bridging of the material over the outlet openings.

In solving this problem, mechanical devices to vibrate the hoppers and shake the material loose have been employed. Also, mechanical agitators have been used to separate the compacted mass of material so that it will fall freely through a bottom outlet opening. Mechanical devices have not been advantageous because of the size I of the covered hopper railway cars and the relative complexity of the devices, such as agitators. In addition, the mechanical devices merely breakup the compacted mate rial and do not speed unloading of the material.

Other attempts at solving the problem include pneumatic unloading systems in which a plenum chamber having an upper sloping surface is provided along which the material to be discharged flows or slides. Air under pressure within the plenum chamber is diifused into the material through a permeable member forming the sloping surface and tends to breakup compacted particle masses and when employed with pulverulent material will fluidize a substantial portion of the pulverulent material in the hopper structure to aid the particles in moving or sliding toward the discharge opening. The present invention is directed particularly to pneumatic unloading systems in which a plenum chamber is provided and is defined by an upper wall or member formed of a porous or permeable material which permits air to seep through the material and diifuse into the material being unloaded adjacent the .plenum chamber.

A low center of gravity in a loaded covered hopper car is highly desirable. Such a low center of gravity is easily obtained with a hopper structure extending downwardly a maximum extent and having a wide opening leading to the outlet structure. The clearance permitted between the bottom of the outlet structure and the track limits the extent to which a hopper sructure may extend downwardly and an outlet discharge nozzle which extends laterally outwardly from the outlet structure permits the outlet structure beneath the hopper to utilize only a minimum vertical space.

The present invention is directed to transport vehicles and the like which are unloaded pneumatically and have a bottom outlet structure with a plenum chamber extending completely around the periphery of the discharge opening in the bottom of the outlet structure. A permeable member defines the upper portion of the plenum chamber and the material to be unloaded pneumatically is supported on the upper surface of the permeable member adjacent the outlet opening. As the permeable member and plenum chamber extend around the entire inner periphery of the. outlet structure, the permeable member must be sufiiciently rigid to withstand the weight of material supported on its upper surface and to resist adequately air pressure within the plenum chamber. A permeable member which is composed of a single membrane formed of a material, such as a fine mesh metal or plastic mate' rial, is not s-ufiiciently rigid to withstand the weight of the material being unloaded and the air pressure within the plenum chamber over a period of time without being undesirably large in thickness. The present permeable member is formed and constructed in such a manner as to provide sufficient rigidity even with a relatively large support area. A large support area for the membrane is desirable in order to obtain a maximum utilization of the cubic capacity of a covered hopper railway car and such an area is provided when the slope of the permeable member relative to the horizontal is relatively small and the outlet structure has a relatively large area.

It is an object of this invention to provide a covered hopper railway car having a bottom outlet structure for pneumatically unloading material in the car in which a maximum utilization is made of the cubic capacity of the covered hopper railway car and the center of gravity of the loaded car is at a minimum height from the upper surface of the track.

Another object of this invention is the provision of a permeable wall or member for a plenum chamber of a pneumatic outlet structure which wall has an exposed surface along which the material to be unloaded easily slides, is easily cleaned with strong solvents or steam, and is sufliciently rigid even with a relatively large surface area.

An additional object is the provision of such an outlet structure for covered hopper railway cars which has a pneumatic discharge nozzle arranged in such a manner as to utilize only a minimum vertical space between the bottom of the hopper structure and the supporting track structure thereby permitting maximum utilization of the cubic capacity of the hopper car.

A further object is the arrangement of a hopper structure in which pulverulent material is pneumatically unloaded in a generally mass flow with the material moving downwardly in a uniform manner and the upper surface of the material remaining substantially level until unloaded.

Briefly, the invention includes a bottom outlet structure secured to the underside of a hopper structure for pneumatically unloading materials and having a plenum chamber formed between a permeable inner wall and the outlet housing, the plenum chamber extending completely around the inner periphery of the outlet structure and around a discharge opening in the bottom of the outlet structure, the upper surface of the sloping permeable inner wall leading to the discharge opening, and a discharge nozzle extending laterally from the discharge opening and fitting within the bottom ofthe outlet housing with a portion of the housing cut away to receive the inlet end of the discharge nozzle. The inner permeable wall or member is easily secured in place within the outlet housing by welding directly to the outlet housing without the use of any intermediate gaskets or ring members to provide support for the member and is of a sutficient rigidity to support the material to be unloaded without undue wear even though a relatively large sup port area is provided. The exposed surface of the permeable wall is relatively dense and smooth to permit material to slide easily over the surface and to allow cleaning of the surface with strong solvents or steam. By having the discharge nozzle extending laterally from the outlet housing, only a relatively small vertical space is utilized by the outlet structure and the hopper structure may extend downwardly to a maximum extent.

or angle relative to the horizontal thereby to effect a mass flow of the material and a relatively fast movement of material along the surfaces to the outlet structure.

The invention accordingly comprises the constructlons hereinafter described, the scope of the invention being indicated in the following claims.

In the accompanying drawings, in which several of various possible embodiments of the invention are illustrated,

FIGURE 1 is a side elevational view of the present invention illustrating a plurality of outlet structures comprising one embodiment of this invention mounted on the bottom of a covered hopper railway car;

FIGURE 2 is a partial elevational view of the railway car of FIGURE 1 with a portion thereof broken away and illustrating one of the hopper structures;

FIGURE 3 is an end elevation of the railway car of FIGURES 1 and 2 with a portion thereof broken away; FIGURE 4 is a plan view of the outlet structure shown in FIGURES 1-3 removed from the hopper structure;

FIGURE 5 is a sectional view taken generally along line 55 of FIGURE 4;

FIGURE 6 is a sectional view taken generally along line 66 of FIGURE 4;

FIGURE 7 is a sectional view taken generally along line 7-7 of FIGURE 4;

FIGURE 8 is a sectional view similar to FIGURE 6 but showing a discharge nozzle removed from the bottom of the outlet structure;

FIGURE 9 is a plan View of the discharge nozzle shown in FIGURE 8;

FIGURE 10 is a side elevational view of the discharge nozzle of FIGURE 9;

FIGURE 11 is an end elevation of the discharge nozzle of FIGURES 9 and 10 with a portion thereof broken away and taken generally along line 1111 of FIGURE 10;

FIGURE 12 is an enlarged fragment of the connection of the outlet structure to the hopper structure and showing the permeable wall secured adjacent thereto;

FIGURE 13 is an enlarged fragment in elevation of a rib supporting the permeable member;

FIGURE 14 is a section taken generally along line 14-14 of FIGURE 13;

FIGURE 15 is a plan view of the permeable member showing a membrane broken away and illustrating the rigid base therebeneath;

FIGURE 16 is a schematic view showing the piping arrangement for the covered railway hopper car and outlet structures shown in FIGURE 1;

FIGURE 17 is a plan view of a separate embodiment of the outlet structure adapted to be removably secured to the bottom hopper structure of a railway car or the like;

FIGURE 18 is a sectional view taken generally along line 1818 of FIGURE 17;

FIGURE 19 is a sectional view taken generally along line 19--19 of FIGURE 18 and showing the discharge nozzle removed;

FIGURE 20 is a side elevation of the discharge nozzle of FIGURE 19;

FIGURE 21 is a plan view of the discharge nozzle shown in FIGURE 20;

FIGURE 22 is an end elevation of the discharge nozzle of FIGURES 20 and 21;

FIGURE 23 is a perspective of a modification of the permeable member employed in the bottom outlet structures of FIGURES 116 and FIGURES 17-22; and

FIGURE 24 is an enlarged fragment of a modified construction for securing the permeable member within the outlet structure.

Referring to the embodiment shown in FIGURES 1-16 of the drawings and particularly FIGURES 1-3, a covered hopper railway car is generally designated 10 and is of the type to which the present invention is applicable. Car 10 includes a plurality of contiguous hoppers or hopper structures 12 separated by bulkheads 14 extending only partially to the top of car 10. Bulkheads 14 serve to strengthen the sides of the car and to minimize the spill-over between adjacent hopper structure 12. A partial cylindrical shell 15 forms the roof and upper sides of car 11). End slope sheets 16 extend downwardly to end hoppers 12 at an angle of around 60 with respect to the horizontal. A side sheet 17 on each side of car 10 extends downwardly from partial shell 15 and each sheet 17 is disposed at an angle of around 70 with the horizontal. The inner surface of each hopper 12 funnels downwardly from a generally rectangular upper opening adjacent bulk head 14 to a generally elliptical lower opening 18 which extends transversely of car 10 beyond the extent of wheels W. The inner surface of each hopper structure 12 which surrounds opening 18 is a smooth arcuate surface. Extending outwardly about the periphery of each opening 18 is a horizontal flange 20. Bulk material may be loaded within hopper car 10 through suitable openings beneath hatch covers 19.

Secured to each flange 20 is an outlet structure generally designated 22. Bulk or finely-divided materials to be pneumatically unloaded, such as granular or pulverulent materials, pass through opening 18 into the respective outlet structure 22. Each outlet structure 22 is positioned centrally of the Width of car 10 and is generally panshaped or dish-shaped to form a relatively smooth, arcuate and shallow inner area. As outlet structure 22 is of a shallow pan-shaped outer contour, only a relatively small vertical space is employed beneath the adjacent hopper 12. Thus, hopper 12 may extend downwardly a maximum'distance within specific clearance requirements to permit a relatively large hopper capacity.

In order to obtain a mass flow of material into the outlet structures from hoppers 12, side sheets 17 and end slope sheets 16 are relatively steep. Mass flow is defined as a condition under which all of the bulk material within a specified hopper moves downwardly uniformly with the top or upper surface of the material in the hopper remaining substantially level during the unloading operation regardless of the amount of material remaining in the hopper. A minimum angle greater than 50 with respect to the horizontal is necessary for the surfaces tunneling into outlet structures 22 in order for finelydivided material to have a mass flow into the outlet structures. It is to be understood that any desired number of outlet structures 22 may be provided on railway car 10.

Referring to FIGURES 4-7 in which a single outlet structure 22 is indicated, each structure 22 has a body housing 24 with an upper peripheral flange 26 secured by suitable bolt and nut combinations 28 to flange 20. Sloping downwardly from flange 26 is a peripheral shoulder 30 forming an inner ledge or seat. A circumferential rim 32 extends downwardly from shoulder 30 and a body portion 34 slopes inwardly from rim 32 at a relatively small degree of inclination. Inclinations between about 5 and 30 form generally shallow panshaped outlet structures and will function effectively while utilizing a relatively small vertical space. As outlet structure 22 is generally oval-shaped, the slope of the outlet structure varies from a maximum along the transverse center line thereof as shown in FIGURE 5 to a minimum along the longitudinal center line thereof as shown in FIGURE 6. Thus, the slope is constantly and generally uniformly decreasing for each quadrant from the transverse center line along line 5-5 of FIG- URE 4 to the longitudinal center line along line 6-6 of FIGURE 4.

It is desirable to have an outlet structure extending transversely of the car to a maximum extent in order to provide a maximum cubic capacity or volume in hopper car and to obtain a relatively low center of gravity in the loaded car. Each outlet structure 22 extends transversely of the car beyond wheels W as shown in FIGURE 3 so that hopper structures 22 may be of a maximum dimension transversely of car 10. The dimension of each outlet structure 22 longitudinally of car 10 is denoted as the width of outlet structure 22 and is substantially smaller than the length of outlet structure 22 which extends transversely of the car.

Sloping downwardly from shoulder 36 to an elongate outlet discharge opening 36 and secured to a main body portion 34 are a plurality of generally T-shaped ribs each generally designated 38. Each rib 38 has an upper flange 39 and a web 40 with a plurality of apertures 42 therethrough, see FIGURES 13 and 14. Each web 40 is welded to body portion 34. To form elongate opening 36, a portion of body portion 34 is cutaway at 44 as shown in FIGURE 4. Fitting within cutaway portion 44 is a discharge nozzle generally designated 46 which is secured, such as by welding, to housing 24 (see FIG- URE 4). Nozzle 46 is a cast structure and is welded to housing 24.

Referring to FIGURES 81l particularly, nozzle 46 includes a plate-like extension 48 having a generally fiat bottom 59 beneath outlet opening 36 and an upper circumferential wall 52 defining the discharge opening 36 extending around bottom 50. Extending from extension 48 is a tubular portion 54 having an inlet opening 56 of an inner generally elliptical contour and an outlet opening 58 of an inner generally circular contour. Inlet opening 56 extends through the adjacent portion of wall 52. The inner peripheral surface of tubular portion 54 gradually changes from an elliptical contour at inlet opening 56 to a circular contour at outlet opening 58. This arrangement permits outlet structure 22 to be mounted in a minimum vertical space. Projecting from the upper surface of tubular portion 54 is a T-shaped rib 38 which fits adjacent a T-shaped rib 38 mounted on body portion 34 to form a smooth continuation thereof as shown in FIGURE 4. Extending downwardly from the outer end of T-shaped rib 38' is an outer shoulder 66 fitting against and secured to housing 24. Extending downwardly from the inner end of T-shaped rib 38 is an inner shoulder 68 formed by the adjacent wall 52. Shoulder 66 is welded to the adjacent edge of body portion 34 for holding and securing nozzle 46 in position.

Mounted on ribs 38 are eight generally triangularshaped segments 72 each segment extending between two adjacent ribs as shown in FIGURE 4. Segments 72 form a permeable member which extends circumferentially around the inner periphery of housing 24 to define a plenum chamber 76 between segments 72 and the inner surface of housing 24. The area beneath rib 38' is also a portion of chamber 79. Each segment 72 is formed of an upper permeable membrane 74 and a lower supporting base 76 which has a sufiicient rigidity to support membrane 74 between adjacent ribs 38 when material is supported on the upper surface of membrane 74 and air under pressure is supplied to plenum chamber 70 through an air inlet conduit or pipe 75. Membrane 74 is formed of a fiber metal material in which metallic fibers having a length to diameter ratio of at least ten to one, and a high as two thousand to one, are individually dispersed and felted to form a random, interlocked non-woven body. The non-woven body is then sintered under reducing conditions at a high temperature to produce welds or metallic diffusion bonds at interfiber contact points. The sintered fiber metal forming membrane 74 is relatively dense but yet is permeable to allow a generally uniform introduction of fiuidizing air from plenum chamber 70. Thus, the porosity of membrane 74, defined as the percent ratio of pore space by volume 6 to the entire volume of the membrane, is relatively small.

Base 76 may be formed, for example, of stainless steel having a plurality of apertures 78 therethrough to permit air under pressure from plenum chamber 70 to pass through apertures 78 and membrane 74. The area of base 76 over nozzle 46 is not perforated for around two inches from inlet 56 so that air will not interfere with the material entering inlet 56. Membrane 74 may be suitably secured to base 76, for example, by an adhesive such as a thermosetting liquid adhesive, or by sintered bonding.

The resistance to the passage of air through a porous medium may conveniently be expressed in terms of air volume passing at a specified pressure drop across the medium. The term permeability is commonly employed as illustrative of this method and is defined as the amount of air measured in cubic feet and at 70 F. and 25% relative humidity which will pass through the area of one square foot of the membrane in one minute when tested under an equivalent pressure differential of two inches of water. A permeability of around 10 has been found to be effective for unloading the bulk material in railway car 10. This rating may be obtained by employing a membrane 74 of around ,4 of an inch in thickness and a stainless steel base 76 of around inch in thickness with apertures 78 including around 60% of the entire surface area of base 76.

Referring to FIGURE 12, base 76 of each segment 72 has an upper marginal portion 79 seated on shoulder 30 and welded thereto as indicated at 80. A lower marginal portion 81 of each segment 72 (see FIGURES 4 and 8) is secured, such as by welding, to the upper surface of wall 52. Membrane 74 has its upper edge 82 spaced downwardly from weld as shown in FIG- URE 12. Adjacent segments 72 are spaced slightly from each other over each rib 38. Adjacent metal bases 76 extend laterally beyond the superjacent membranes 74 and are welded at 83 to the upper surface of flange 39 as shown in FIGURE 14.

It is not necessary for base 76 and membrane 74 to be tightly secured to each other except along the upper and lower edges of the membrane as lateral air flow between membrane 74 and base 76 is not undesirable, unless, of course, the air leaks considerably between membrane 74 and base 76 adjacent upper edge 82 and lower marginal portion 81 (see FIGURE 8).

Metallic base 76 permits the permeable member or wall to be welded permanently in place while the inner surface of membrane 74 which is in contact with the lading to be unloaded is relatively smooth. Thus, no retaining bolts or similar retaining means are required to hold membrane 74 in position which might possibly interfere with the flow of material along the relatively smooth and dense surface of the membrane. Additionally, if it is desired to replace a defective segment 72, only the respective defective segment need be removed and a new segment 72 may be welded into position. Since membrane 74 is relatively dense, it may be easily cleaned with water or solvent without any resulting damage or deterioration to the membrane. The small pore size of membrane 74 minimizes the filling or clogging of the pores with the material to be unloaded, such as cement. Also, the path of the air passing through the sintered metal membrane is tortuous and any material which tends to fill the pores must follow a tortuous path thereby permitting only a minimum amount of material to penetrate the surface of the membrane.

Referring to FIGURE 16, the piping system for conveying air under pressure to car 10 and for removing the lading from the car is shown. Air under pressure is sup plied at either inlet 88 of pipe 90 from a suitable low pressure air source (not shown) of around 15 psi. such as commonly found on many highway trailers. Inlet pipes 75 connect to a main supply pipe 92'and each has a valve 94 therein to selectively control the supply of air to the plenum chamber of each outlet structure 22. Each valve 94 also includes a check valve. Air is also supplied from inlet 88 to a lading discharge pipe 96 which has an outlet 97 through which the material is discharged from car 10 to a suitable storage facility (not shown). Nozzles 46 are each connected to discharge pipe 96 and each nozzle has a discharge valve 98 so that the flow of material from each outlet structure 22 may be selectively controlled. A main valve 100 in pipe 96 selectively controls the flow of air through pipe 96 for unloading car 10.

Operation is as follows:

A suitable source of air under pressure is connected to inlet 88 with valve 100 closed and all valves 94 for the plenum chambers 70 being opened to permit air under pressure in the plenum chambers. A suitable conduit (not shown) is connected to outlet 97 and leads to a suitable storage facility. Air from each plenum chamber 70 permeates the associated membrane 74 and mixes with the material or lading adjacent the membrane. The pulverulent material is fluidized so that it behaves like a liquid by reducing the internal strength of the mass of material. The air pressure within car It gradually increases after inlet 88 is connected to an air source and upon reaching around 14 p.s.i., valve 100 is opened to permit air within pipe 96, valves 98 remaining closed. To commence the discharge of the lading, the first two valves 98 adjacent outlet 97 are opened and the lading is unloaded through the associated nozzles 46. The outlet structure 22 closest adjacent outlet 97 will be unloaded first, and then the lading is unloaded immediately from the next succeeding outlet structure 22, the valve 98 being closed for the outlet structure 22 which has been unloaded and the next succeeding valve 98 being opened. Thus, a continuous flow of lading is provided from one hopper structure 12 to the next. After all of the outlet structures 22 have been emptied, a relatively complete cleanout of material may be effected by opening each valve 98 individually for a few seconds. It is to be understood that plenum valves 94 may in some instances, such as during operation with a limited air supply, be operated simultaneous with the respective associated valve 98.

A relatively small period of time is requird to unload as a uniform mass flow of material is obtained. During unloading of a hopper, the upper surface of the lading in the hopper remains generally level during all stages of unloading. This is important as car 10 is under air pressure when being unloaded and aids in assisting the material toward the outlet structure. If the material un loads unevenly, air above the material will communicate directly with the outlet opening before the car is fully unloaded. A relatively large amount of material usually remains in the outlet structure 22 when mass flow is not effected. Once direct communication is effected between air within the car and the outlet opening, the remaining material may only be unloaded by gravity flow to the outlet opening where it is entrained in a high velocity air stream which results in undesirable dusting and an inefficient employment of available air.

Referring to FIGURES 17-22, another embodiment of an outlet structure is illustrated in which outlet structure 22A is of a generally frusto-conical shape. Four segments 72A are secured, such as by welding, to ribs 38A secured to housing 24A. Segments 72A are formed in a manner similar to segments 72. Air under pressure is supplied to plenum chamber 70A through an inlet pipe 75A. As outlet structure 22A is frusto-conical in shape, the slope of segments 72A is generally uniform about the entire inner periphery of outlet structure 22A. A portion of housing 24A is cut away to receive discharge nozzle 46A which is secured, such as by welding, to housing 24A. Discharge nozzle 46A has a plate-like extension 1112 generally circular in outer contour and forming a bottom for bottom opening 104. A tubular portion 106 of discharge nozzle 46A has a circular contour. Segments 72A are secured to the upper surface of wall 52A which extends around the outlet opening.

Referring to FIGURE 23, a separate embodiment of a permeable member is illustrated in which the separate metallic base 76 illustrated in FIGURES ll6 is eliminated. Permeable member indicated generally 198 has a wire fabric of a fine mesh pressed into the permeable fiber metal membrane 74A on each surface thereof during the sintering operation. VJire fabric 110 provides adequate rigidityfor membrane 74A and may be Welded directly to housing 24 or 24A as is permeable member 72 of the embodiment illustrated in FIGURES 1-16.

Referring to FIGURE 24, another construction for securing the upper portion of the permeable member in position is illustrated which eliminates welding of the permeable member to shoulder 30. Metallic base 76B has a generally horizontally extending rim 112 about its periphery fitting between flange 20 of hopper structure 12 and flange 26 of outlet structure 22. A suitable gasket 114 is positioned on each side of rim 112. Membrane 74B is secured, such as by a thermosetting adhesive, to base 76B to form a permeable wall. Metallic base 763 may be easily clamped between flanges 20 and 26 without welding. The lower portion of the permeable member is secured similarly to the embodiment of FlGURES ll6.

While outlet structure 22 has been illustrated particularly for employment with a covered hopper railway car, it is to be understood that outlet structure 22 may be employed with other types of hopper structures, such as hop per structures on highway trailers or the like.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous result-s attained.

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 drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A bottom outlet structure adapted to be secured beneath an opening in the bottom of a hopper to receive and effect pneumatic discharge of material from the hopper through the opening, said bottom outlet structure comprising a generally oval, pan-shaped housing tunneling downwardly to a bottom discharge opening and adapted to communicate with the opening in the bottom of the hopper for receiving material therefrom, a gas permeable member fitted within the housing and being generally funnel-shaped to provide inner surfaces converging from the opening in the hopper, said gas permeable member being spaced inwardly from the housing to form a plenum chamber extending circumferentially between the housing and the gas permeable member and adapted to communicate with. a source of gas for supplying gas under pressure to the plenum chamber, said gas permeable member comprising a gas permeable membrane on the upper side thereof and a generally rigid base on the lower side thereof having a plurality of apertures therethrough, a circumferential wall projecting generally upwardly from said housing to form said bottom discharge opening, a plurality of support ribs in the plenum chamber extending longitudinally generally radially from said circumferential wall and supporting the gas permeable member, said ribs having air passages there through to permit a substantially free flow of air about the circumferential wall, said base being secured along its upper marginal portion to the housing and having a lower marginal portion secured to said circumferential wall and extending around the bottom discharge opening, said housing having a portion thereof cutaway adjacent the discharge opening, and a discharge nozzle received within said cutaway portion and extending generally in a horizontal direction from the bottom discharge opening whereby material being unloaded moves along the permeable member to the bottom discharge opening.

2. An outlet structure as set forth in claim 1 wherein said housing has an outer flange extending around its upper periphery and a downwardly sloping inner surface adjacent said outer flange forming a smooth ledge thereon, and said permeable member comprises a permeable membrane on the upper side formed of a sintered fiber metal and a metallic base on its lower side adjacent the permeable membrane, said metallic base having its upper marginal portion secured to said ledge and having a plurality of apertures therethrough to permit the passage of air from the plenum chamber.

3. An outlet structure as set forth in claim 2 wherein said permeable member is divided into a plurality of generally triangularly-shaped segments each supported on and secured to at least one of said support ribs.

4. A covered hopper railway car for carrying and unloading finely-divided materials comprising a hopper structure having downwardly directed surfaces disposed at an angle of at least 50 with respect to the horizontal and funneling through a bottom opening, a bottom outlet structure removably secured beneath the opening in the hopper structure to receive and effect pneumatic discharge of the material received from the hopper structure, said bottom outlet structure comprising a generally pan-shaped housing funneling downwardly to a bottom discharge opening and communicating with the opening in the hopper structure to receive material therefrom, a gas permeable member fitting within the housing and being generally funnelshaped to provide surfaces converging from the opening in the hopper structure, said gas permeable member being spaced inwardly from the housing to form a plenum chamber extending circumferentially between the housing and the gas permeable member, said gas permeable member comprising a gas permeable membrane on the upper surface thereof and a generally rigid base on the lower surface thereof having a plurality of apertures therethrough, a circumferential wall projecting generally upwardly from said housing to form said bottom discharge opening, a plurality of support ribs in the plenum chamber extending longitudinally generally radially from said circumferential wall and supporting the gas permeable member, said ribs having air passages therethrough to permit a substantially free flow of air about said circumferential wall, said housing having a portion thereof cutaway adjacent the bottom discharge opening, said gas permeable member having a lower marginal portion secured to said circumferential wall around the entire periphery of the bottom opening, a discharge nozzle received within said cutaway portion and extending generally in a horizontal direction from the discharge opening, and means to supply gas under pressure to the plenum chamber at a suflicient rate to free any finely-divided material adjacent the gas permeable member whereby the material moves downwardly along the inner surface thereof to the discharge opening.

5. A covered railway hopper car for carrying and unloading finely-divided materials as set forth in claim 4 wherein said generally pan-shaped housing has an outer flange extending around its upper periphery and a downwardly sloping inner surface adjacent said outer flange forming a smooth ledge thereon, said permeable membrane being sintered fiber metal and said base being a steel sheet metal having sufiicient rigidity to withstand the weight of the material on the membrane and the air pressure within the plenum chamber, said base having its upper marginal portion secured to said ledge to hold the permeable member in position.

6. A covered hopper railway car for carrying and unloading finely-divided material as set forth in claim 5 wherein said permeable member is divided into a plurality of generally triangularly-shaped segments each supported on and secured to at least one of said support ribs.

7. A covered hopper railway car for carrying and unloading finely-divided materials comprising a hopper structure having downwardly directed surfaces disposed at an angle of at least with respect to the horizontal and funneling into a generally elliptical bottom opening having a peripheral outer flange therearound, a bottom outlet structure beneath the opening in the hopper structure to receive and effect pneumatic discharge of material from the hopper structure, said bottom outlet structure comprising a housing being generally of an oval panshape and funneling downwardly to an elongate bottom discharge opening, the housing having a length extending transversely of the car to an extent beyond the wheels on each side of the railway car, an upper peripheral flange on said housing adapted to be secured to said outer flange of the hopper structure adjacent said generally elliptical bottom hopper opening, a gas permeable member mounted within the housing and forming a plenum chamber between the gas permeable member and the housing, means in the plenum chamber between the permeable member and said housing for supporting the permeable member, a circumferential wall projecting generally upwardly from said housing to form said bottom discharge opening, said permeable member having a lower margin-a1 portion secured to the upper surface of said circumferential wall about the entire periphery of the elongate bottom outlet therein, said housing having a portion thereof cutaway adjacent the discharge opening, and a discharge nozzle received within said cutaway portion and extending generally in a horizontal direction from the elongate bottom opening whereby material being unloaded moves along the permeable member to the bottom opening.

8. A covered hopper railway car as set forth in claim 7 wherein said permeable member comprises an upper permeable membrane of sintered metal and a lower supporting metal base having a plurality of apertures to permit the passage of gas from the plenum chamber through the permeable member.

9. A covered hopper railway car for carrying and unloading finely-divided material as set forth in claim 7, wherein said permeable member comprises a permeable membrane of sintered metal and a meshed metal fabric on each side of said membrane to provide rigidity for said permeable member.

10. A covered hopper railway car as set forth in claim 8 wherein said permeable membrane is divided into a plurality of generally triangularly-sh-aped segments each supported on said metal base.

11. A covered hopper railway car for carrying and unloading finely-divided material as set forth in claim 8 wherein said supporting metal base has a peripheral rim fitting between the peripheral flanges of said housing and hopper structure, and means holding said flanges tightly together for clamping said peripheral rim therebetween.

References Cited by the Examiner UNITED STATES PATENTS 2,395,727 2/1946 Devol 30229 2,676,851 4/1954 Sylvest 302--29 2,924,489 2/1960 Beckmann 302-53 2,975,915 3/1961 Lindley 30252 3,080,173 3/1963 Johnson et al. 30252 3,180,689 4/1965 Albert 302-52 ANDRES H. NIELSEN, Primary Examiner.

Claims (1)

1. A BOTTOM OUTLET STRUCTURE ADAPTED TO BE SECURED BENEATH AN OPENING IN THE BOTTOM OF A HOPPER TO RECEIVE AND EFFECT PNEUMATIC DISCHARGE OF MATERIAL FROM THE HOPPER THROUGH THE OPENING, SAID BOTTOM OUTLET STRUCTURE COMPRISING A GENERALLY OVAL, PAN-SHAPED HOUSING FUNNELING DOWNWARDLY TO A BOTTOM DISCHARGE OPENING AND ADAPTED TO COMMUNICATE WITH THE OPENING IN THE BOTTOM OF THE HOPPER FOR RECEIVING MATERIAL THEREFROM, A GAS PERMEABLE MEMBER FITTED WITHIN THE HOUSING AND BEING GENERALLY FUNNEL-SHAPED TO PROVIDE INNER SURFACES CONVERGING FROM THE OPENING IN THE HOPPER, SAID GAS PERMEABLE MEMBER BEING SPACED INWARDLY FROM THE HOUSING TO FORM A PLENUM CHAMBER EXTENDING CIRCUMFERENTIALLY BETWEEN THE HOUSING AND THE GAS PERMEABLE MEMBER AND ADAPTED TO COMMUNICATE WITH A SOURCE OF GAS FOR SUPPLYING GAS UNDER PRESSURE TO THE PLENUM CHAMBER, SAID GAS PERMEABLE MEMBER COMPRISING A GAS PERMEABLE MEMBRANE ON THE UPPER SIDE THEREOF AND A GENERALLY RIGID BASE ON THE LOWER SIDE THEREOF HAVING A PLURALITY OF APERTURES THERETHROUGH, A CIRCUMFERENTIAL WALL

Images