| 摘要 |
A new fill valve for use in cementing operations in a wellbore extending down into the earth has been invented, the fill valve having a tubular housing having a valve seat, a valve member slidably mounted in said tubular housing, a spring for biasing said valve member towards a closed position, the valve member having a head engageable with the valve seat of the tubular housing to close the valve, selectively releasable apparatus for releasably maintaining the fill valve in an open position, the selectively releasable apparatus including a shear ring breakable in response to pressure thereon, a slider movably disposed in a slider housing mounted in the tubular housing, a lower end of the slider initially projecting down and out from the slider housing and abutting a top end of the valve member and preventing the valve member from moving, a top end of the slider abutting the shear ring, the slider prevented initially from moving by the shear ring, the slider movable in response to pressure of fluid in the wellbore. |
