| 摘要 |
<p>Disclosed is a float valve that allows passage of objects down the drill string while the drill string is within the borehole using a flap valve and sliding sleeve. The float valve has an outer hollow housing for connection to and location between upper and lower sections of the drill string. A flap valve is located at least in part within the outer hollow housing to allow or disallow flow of fluid and/or objects through the outer hollow housing via the float valve. A sliding sleeve is located at least in part within the outer hollow housing, to translate at least in part within the outer hollow housing, such that in a first position the sliding sleeve is clear of the flap valve, and in a second position the sliding sleeve retains the flap valve open to allow the flow therethrough. The sliding sleeve can be remotely actuated between the first and second positions to allow the flap valve to close or to retain the flap valve open, such that when the flap valve is retained open objects and or fluid can pass from the upper section to the lower section and vice versa, through the outer hollow housing.</p> |
