| 摘要 |
A downhole valve 26, such as a downhole injection valve, comprises a valve body 32 defining a sealing surface 34 and a flow port 36 , a valve member 50, such as a poppet, mounted within the valve body and including a sealing arrangement 60, and a protection sleeve 72 mounted within the valve body. The valve member is moveable within the valve body from a closed position (fig 2a) in which the flow port is closed and the sealing arrangement sealingly engages the sealing surface of the valve body, towards an open position in which the flow port is opened (fig 2c) and the sealing arrangement is disengaged from the sealing surface and received within the protection sleeve. |
