| 摘要 |
A mud saver valve, positionable at the bottom of the drill string, above the bit, which includes an elongated body portion; portion of the valve housing a compressible spring a pressure; a valve mechanism which is a sliding sleeve moveable between open and closed positions within the valve; while in the closed position, drilling fluid cannot pass through the valve; when a combination of static and pump pressure exceeds the setting pressure of the dome, the sleeve will be moved by actuation pistons to the open position, at which drilling fluid is allowed to through the valve. Also, wherein when the valve is normally closed, as long as the fluid column pressure is less than the setting pressure, the valve remains closed, and allows the drill string to be disconnected and a section of pipe can added without the fluid draining from the drill column above the bit, and thus saving fluid.
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