Inventors:
Bradley W. Mosman - Shawnee OK
Frederick A. Hausler - Emporia KS
Assignee:
ERC Industries, Inc. - Houston TX
International Classification:
F16K 4104
F16K 4118
F16K 4300
Abstract:
A valve, having provision for replacing stem packing while the valve is under pressure, has a valve body with a flow passageway through it, a gate that is vertically positioned to open and close the passageway, a stem extending upwardly from the valve body, the lower end being attached to the gate, a bonnet secured to the valve body by which the valve body open top is closed, the stem extending through an opening in the bonnet, a packing box slidably positioned in an opening in the top of the bonnet and receiving the stem, a back seat ring is positioned within the opening of the bonnet below the packing box and having a circumferential sealing surface surrounding the valve stem, the valve stem having an integral enlarged diameter shoulder so that when the stem is in the full upward position the packing box can be moved downwardly in the direction towards valve body forcing the back seat ring sealing surface to seal against the stem shoulder formed on the valve stem to permit packing retained within the packing box to be removed and replaced while the valve is under pressure.