Conveyors: fluid current – Ambulant or portable – Vehicle mounted
Reexamination Certificate
1999-04-19
2001-08-14
Olszewski, Robert P. (Department: 2167)
Conveyors: fluid current
Ambulant or portable
Vehicle mounted
C052S197000, C053S151000, C105S248000, C406S145000
Reexamination Certificate
active
06273647
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to railway hopper cars and, more particularly, to hoppers and product discharge apparatus associated with pressure discharge railway hopper cars.
BACKGROUND OF THE INVENTION
Closed railway hopper cars with pneumatic systems for unloading are often 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 in an air flow through product transfer conduits from the car. Air pressure within the hopper car during the unloading procedure may be maintained at approximately fifteen psi gage. The pneumatic discharge or unloading system associated with a pressure discharge railway hopper car may include an air supply conduit for directing a portion of the air supplied to the hopper car into the discharge line leading from the car to the destination of the product being discharged. The air pressure in the discharge line may be 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. Reference may also be made to U.S. Pat. No. 5,433,559 entitled Pressurized Hopper Car.
Flours, 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-form commodity may, usually to advantage, be transported in such hopper cars. An enclosed hopper car and the pneumatic discharge apparatus protect the contents of the car and minimizes product losses during the loading, transportation, and the discharge process. Also, pneumatic transport is often the most cost effective, efficient method of moving large quantities of dry, bulk product.
Pressure discharge hopper cars may have a single product outlet leading from each hopper located near the center of the car and opens to a hopper discharge conduit located therebelow. Discharge conduits connected to each hopper outlet communicate with the hopper outlet and are typically connected to a main product transfer conduit extending along the side of the car. Providing piping immediately below each hopper outlet within appropriate American Association of Railroads (AAR) plate may limit the height above the track of the bottom of each hopper.
SUMMARY OF THE INVENTION
In accordance with teachings of the present invention, disadvantages and problems associated with the fabrication, assembly and use of pressure discharge railway hopper cars have been substantially reduced or eliminated.
One embodiment of the present invention provides a pressure discharge hopper car having an increased capacity, a lower center of gravity, and lower air resistance than previously known hopper cars of comparable size and type. One aspect is to reduce the costs of designing, producing parts for, and assembling pressure discharge railway cars. Another aspect is to provide a pressure discharge railway car that can readily handle a wide variety of dry materials and that can be unloaded more quickly and with fewer operating steps than previously known cars of comparable size.
A particular embodiment of the present invention provides a pressure discharge railway hopper car that includes a car body having a plurality of hoppers arranged in adjacent relation longitudinally of the car body. Each hopper may have a discharge opening at its bottom end with an aerator tub assembly attached to the bottom end. The aerator tub assembly preferably includes a top opening extending generally coextensive with the discharge opening of the hopper. Each aerator tub assembly may be symmetrical with respect to the longitudinal centerline of the car with two aerator units respectively disposed opposite sides of the centerline. Downwardly convergent inclined walls of each section define two outlet openings at substantially the lowermost portion thereof. The respective aerator units divide the flow of product from each hopper when the car is being unloaded approximately in half, one-half of the product on one side of the longitudinal centerline of the car being discharged through the outlet of the aerator unit on that side of the centerline and the remaining half being discharged through the outlet of the aerator unit on the other side of the centerline.
Technical advantages of the present invention include dividing the discharge paths of each hopper approximately in half along the longitudinal centerline such that the upper ends of the inwardly sloping side walls (hopper side skirts) of each hopper can be at a relatively low height above the bottom of the AAR Plate and laterally close to the sides of the AAR plate.
Another technical advantage includes the width between the hopper side skirts which can be relatively large. The sloping side walls of each aerator unit of each aerator tub assembly, each of which side walls may have a slope above a preselected valve to maintain gravity flow of all products for which the car is designed, which may eliminate the need for any aeration devices disposed laterally of the respective aerator units. The lateral walls adjacent the centerline, which are preferably joined at an apex, divert product from the center portion of the car to the outlets of the aerator units. Yet another technical advantage includes the increase in size of the lower portion of the car body, thus increasing the capacity and lowering the center of gravity of the resulting car body, as compared to comparable cars with a single center outlet from each hopper. The total height of each hopper and its associated aerator tub assembly is kept relatively low—the side sheets of the car body may be taller and farther apart at the bottom. The side skirts of the hoppers may be planar, which simplifies making piece-parts for the car body and assembling the resulting hopper car.
Still another technical advantage includes the product discharge conduit which leads substantially horizontally and laterally from the outlet of each aerator unit toward the centerline of the car body. Each product discharge conduit may be a length of pipe having an opening in its wall. The lower ends of the side walls and end walls of each aerator unit of each aerator tub assembly are joined at the perimeter of the outlet to the walls of the pipe around the perimeter of the opening in the pipe wall. This arrangement requires only about half of the pipe diameter between the bottom of the tub and the bottom of the applicable AAR Plate. A full pipe diameter of the discharge pipe may open laterally. The half pipe immediately below the aerator unit presents a favorable shape for completely emptying the car.
In conjunction with the outlet conduit of each aerator unit, a generally L-shaped discharge pipe may be associated with each aerator tub assembly. Each L-shaped discharge pipe may have a longitudinal leg that is connected to the product discharge conduits of the two aerator units of the associated aerator tub assembly located between the aerator units and a lateral leg that extends transversely to the centerline to an outlet end laterally outwardly of the aerator tub assembly. The L-shaped pipes optimize use of the space between the aerator units of each aerator tub and between adjacent aerator tubs and conserve space outboard of the aerator units. In a particular embodiment a main discharge pipe may extend longitudinally along a side of the rail car laterally of the aerator tub assemblies. The L-shaped
Sande Jerry W. Vande
Smith Stephen W.
Baker & Botts L.L.P.
Olszewski Robert P.
Ridley Richard
TRN Business Trust
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