Wellhead with safety valve for pumping well
US4907650A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 3, 1989 |
| Grant date | Mar 13, 1990 |
| Priority date | — |
| Expiry date | Jul 3, 2009 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B34/02
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A wellhead for a polished rod pumping unit to provide emergency closure of the bore through the wellhead in the event of breakage of the polished rod. The valve assembly includes a flapper valve mounted on a swivel pin for movement between a vertical open position and a horizontal closed position across the wellhead bore. The flapper valve is spring biased toward the open position. A well pressure responsive cylinder and piston assembly is mounted on the side of the wellhead with an operating rod into the wellhead against the flapper valve to move the valve from the open position to a horizontal closed position. The piston is exposed to well pressure on the one side urging the piston outwardly to the valve open position and a spring engages the piston on the opposite side biasing the piston inwardly toward the valve closed position when well pressure is not sufficient to keep the spring compressed. One form of the wellhead includes a packing assembly for sealing around the polished rod. A second embodiment includes only the valve assembly which is used with a standard packing assembly. A third embodiment of the wellhead includes a swivel mounted packing assembly to permit the polis…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.