Railway rolling stock – Special car bodies – Dumping
Reexamination Certificate
1999-04-19
2001-05-29
Morano, S. Joseph (Department: 3617)
Railway rolling stock
Special car bodies
Dumping
C105S247000, C052S045000, C052S047000, C052S050000, C052S051000, C052S052000
Reexamination Certificate
active
06237505
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to railway hopper cars and, more particularly, to a large capacity car body for pressure discharge railway hopper cars.
BACKGROUND OF THE INVENTION
Closed railway hopper cars with pneumatic systems for unloading them are well known and widely used for the transportation of powdered and granular products. For cars with positive pressure pneumatic systems, air is supplied from an external source to pressurize the interior of the car body and simultaneously fluidize the dry, bulk product carried within the car to enable it to be conveyed in a fluidized state by air flow through product discharge conduits from the car. An air pressure of about fifteen psi gage may be maintained within the hopper car during the unloading procedure. Ordinarily, the pneumatic discharge or unloading system associated with a pressure discharge railway hopper car includes an air supply conduit for directing a portion of the air supplied to the hopper car directly into the discharge conduit or line. The air pressure in the discharge line is generally maintained at two or three psi below the pressure within the hopper car.
Trinity Industries, Inc., the assignee of the present invention, manufactures and sells Power Flo® pressure discharge railway cars with pneumatic unloading systems. An example of aeration equipment and a pneumatic discharge system for removing dry, bulk material from hopper style containers is described and shown in U.S. Pat. No. 3,929,261 entitled
Aeration Device and Method for Assisting Discharge of Material from Containers.
Flour, starch, and similar powdery food products are examples of dry, bulk material suited for loading, transportation and discharge with an enclosed hopper car having a positive pressure pneumatic unloading system. Any dry powder, granular, or pellet-type product may, usually to advantage, be transported in such hopper cars. An enclosed hopper car in cooperation with the pneumatic system protects the contents of the car and minimizes product losses during loading, transportation, and discharge processes. Also, pneumatic transfer is often the most cost effective, efficient method for handling large quantities of dry, bulk fluent materials.
Except for a spherical vessel, which is impractical and not necessary for the relatively low pressure involved, a generally cylindrical vessel is often the most efficient form for the body of a pressure discharge railway hopper car. The generally cylindrical wall of such a vessel is typically self-supporting with respect to forces due to internal pressure, which tend to produce uniform circumferential tensile stresses in portions of the cylindrical wall. A normal requirement for such containers is that the cylindrical wall be sufficiently thick to endure the tensile stress. A generally cylindrical shape is also effective in carrying its own load and the load of the product it contains, although supplementary longitudinally extending, vertical load-carrying members are often desirable, and usually necessary, to prevent buckling of the tank.
A disadvantage of a generally cylindrical car body for a pressure discharge railway hopper car is that it often does not effectively use the available AAR Plate “C” boundaries, which in end profile are essentially rectangular, except for small triangular cut-away areas in each corner. From the point of view of maximizing load carrying capacity, a car with an end profile approximating the AAR Plate “C” rectangle is desirable. Such a car would have flat sides and a flat roof, but it would require thicker wall plates and numerous side and roof stiffeners to keep the side and top walls from deforming, thus considerably increasing the costs of manufacturing parts and of assembling the car.
SUMMARY OF THE INVENTION
Accordingly, a need has arisen in the art for an improved large capacity car body for pressure discharge railway hopper cars. The present invention provides a large capacity car body for pressure discharge railway hopper cars that substantially eliminates or reduces problems associated with prior car bodies for railway hopper cars.
One aspect of the present invention is to provide a pressure discharge hopper car having a greater capacity than previously known hopper cars of comparable size and type. Another aspect is to reduce the costs of designing, producing parts for, and assembling pressure discharge railway cars. A further aspect is to add load carrying capacity for a given AAR profile without unduly increasing manufacturing costs, avoid increasing aerodynamic drag, and retain an interior which may be readily fully emptied and easy to clean and maintain.
The aforementioned are attained, in accordance with teachings of the present invention, by a large capacity car body for a pressure discharge railway hopper car that forms a chamber and may include end slope sheets, and a plurality of intermediate slope sheet units, each of inverted “V” shape. The intermediate slope sheet units and the end slope plates form the end walls of a plurality of hoppers in the lower portion of the car body. A side sheet may form each side of the car body, attached to each of the intermediate slope sheet units and to the end assemblies. Each side sheet preferably has a uniform convex curvature outwardly with respect to the interior chamber in end profile along its length. A top sheet forms a top of the car body and is attached to the end assemblies. The top sheet preferably has a uniform convex curvature outwardly with respect to the interior chamber in end profile along its length. An upper edge portion of each side sheet may form an obtuse included angle with a side edge portion of the top sheet.
A crossridge frame may be associated with each of the intermediate slope sheet units. Each crossridge frame preferably has an upwardly extending side stiffener rib attached to each end of the intermediate slope sheet unit and to each of the side sheets, each side stiffener rib being curved to match the curvature of the side sheet, and a top stiffener rib extending between the upper ends of the side stiffener ribs and attached to the top sheet, the top stiffener rib being curved to match the curvature of the top sheet. A corner connector preferably joins an upper end portion of each side stiffener rib to an end portion of the top stiffener rib. Each corner connector may have a side arm portion engaging and fastened to the upper end portion of the side stiffener rib, a top arm portion engaging and fastened to the end portion of the top stiffener rib, and a juncture portion joining the side arm portion and top arm portion at an angle corresponding to the obtuse angle between the upper edge of each side sheet and the side edge of the top sheet.
The arrangement of the side sheets and top sheet with an obtuse angle between them makes it possible to use more of the upper corner portions of the AAR Plate “C” end profile, thus increasing the capacity of the car body, as compared with a car having a nearly cylindrical end profile. The forming of each crossridge frame from two curved side members, a curved top member, and corner connectors, simplifies manufacture by eliminating complicated and time-consuming welding operations, especially at the corner junctures. The connectors ensure the accuracy and required strength at the corner junctures.
Although other smooth curvatures are possible, in one embodiment of the present invention the side stiffener ribs and side sheets are preferably substantially arcuate in end profile and have a first radius. The top stiffener ribs and top sheet are substantially arcuate in end profile and have a second radius. The first radius is preferably substantially greater than the second radius. For one application, the first radius may be about eleven feet and the second radius about seven feet. The lateral extremities of the associated side sheets may be spaced apart by about ten feet, eight inches. The top sheet may have a span of about eight feet, five inches. The first and second radius and the other dimensions coope
Sande Jerry W. Vande
Smith Stephen W.
Baker & Botts L.L.P.
Morano S. Joseph
Olson Lars A.
TRN Business Trust
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