Valve having provision for replacing stem packing while the valve is under pressure
US5743288A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 12, 1997 |
| Grant date | Apr 28, 1998 |
| Priority date | — |
| Expiry date | Mar 12, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/6072
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.