Overcenter valve control system and method for drilling
US5033266A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 25, 1989 |
| Grant date | Jul 23, 1991 |
| Priority date | — |
| Expiry date | Aug 25, 2009 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B44/02
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A drill feed control system for controlling the force exerted on a drill string having substantial weight. A feed cylinder, which has a first end and a second end, is connected to the drill string. Fluid is pumped from a reservoir to displace the feed cylinder. A first conduit is connected to the first end while a second conduit is attached to the second end. A variable displacement pump displaces fluid from the reservoir, within the first conduit, to the first end of the feed cylinder. A feed pressure control regulates the pressure of the variable displacement pump. An overcenter valve, which is connected to the second conduit, restricts the fluid exiting the second conduit. A relief valve controls the flow of fluid to a pilot conduit which extends between the first conduit and the overcenter valve. An orifice or check valve to release the pressure is connected to the pilot conduit such the the pressure in the pressure conduit will respond to a pressure increase or decrease in the first conduit. The pressure in the pilot conduit and the second conduit interact to open the overcenter valve.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.