Receptacles – Closures – With condition responsive vent or valve
Reexamination Certificate
1999-08-27
2001-10-02
Shoap, Allan N. (Department: 3727)
Receptacles
Closures
With condition responsive vent or valve
C105S377050, C220S203010, C220S373000, C220S374000, C220S844000
Reexamination Certificate
active
06296135
ABSTRACT:
DESCRIPTION
This invention relates in general to a hatch cover for a hatch opening of a railcar, and more particularly to a vent-on-demand hatch cover for a hopper car which normally maintains a closed and sealed relation between the outside air and the compartment and which allows air flow into the compartment when a vacuum is produced inside the compartment.
BACKGROUND OF THE INVENTION
Heretofore, it has been well known to provide hatch covers for railcars. More particularly, the heretofore known vented hatch covers included passageways with openings to the outside air and to the compartment which is closed by the cover for the purposes of allowing the venting of air between the outside and the compartment and which allow unloading of the contents without removing the cover. Where shippers of goods want to assure no contaminants can be transferred by air flow, a non-vented hatch cover is used.
When unloading a compartment of a railcar having non-vented hatch covers, it is necessary to remove the hatch covers in order to provide sufficient air flow into the compartment to allow the contents to be discharged from the compartment and also to eliminate any implosion risks during unloading operations.
Accordingly, there is a need to provide a hatch cover for a hatch opening that will seal out contaminants during shipping while also allowing unloading without the necessity of removing the hatch cover from the opening.
SUMMARY OF THE INVENTION
The present invention relates to a vent-on-demand hatch cover that solves a problem heretofore known where it is necessary to remove a hatch cover for unloading of a compartment of a hopper car where it is desired to seal off the hatch openings against contaminants entering the compartment during shipping. Except for the vent-on-demand feature of the hatch cover of the present invention, the hatch cover is similar to the vented hatch cover in copending application 08/868,463, ('463 application) filed Jun. 3, 1997 now Pat. No. 5,960,980, and assigned to the assignee of this application. Accordingly, the disclosure in that copending application is incorporated herein by reference.
The hatch cover in the '463 application includes an upper member and a lower member in assembled relation which defines peripheral openings for the outside air and a central opening for communication with the inside compartment air, and interconnecting passageways for controlling the air flow and reducing the entry of contaminants into the compartment during shipping. Thus, the vented hatch cover in the '463 application continually allows the venting of air and the air flow between the ambient and the compartment during the time that the cover is in place on the hatch opening. Moreover, the vented hatch cover of the '463 application allows unloading of the compartment without the necessity of removing the hatch cover as air can flow into the compartment through the air flow passageways.
The present invention differs from that disclosed in the '463 application in that a closure member is provided for the opening in the cover that communicates with the interior of the compartment. This closure member is resiliently biased into closed position and opens on demand during unloading operations or whenever the pressure within the compartment differentiates sufficiently from the outside pressure. Thus, all implosion risks are avoided. Further, the closure member opens during unloading when venting is needed and thereafter closes automatically when a car unloading operation is completed in order to seal out any possible entry of contaminants.
It is therefore an object of the present invention to provide a vent-on-demand hatch cover that allows venting on demand during unloading operations.
A further object of the present invention is in the provision of a vent-on-demand hatch cover for a railcar that includes a closure member normally resiliently biased into closed position and openable upon reduction of the air pressure within the compartment of a railcar during unloading operations or during any other unusual air pressure differential situations.
Other objects, features and advantages of the invention will be apparent from the following detailed disclosure, taken in conjunction with the accompanying sheets of drawings, wherein like reference numerals refer to like parts.
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Anderson John D.
Peach, Jr. Walter J.
Hylton Robin A
Shoap Allan N.
Zeftek, Inc.
Zickert Lloyd E.
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