| 摘要 |
The apparatus (10) for delivering grease through the individual string (12) includes a tubular member (14) for holding a supply of grease, a piston (16) sealing slidable through the tubular member (14) and a first valve (18) coupled to a downstream end (20) of the member (14). Valve (18) has a body (22) provided with orifices (24) and a collar (26) slidably mounted over an end of the body (22) and biased to a sealing position in which it seals the orifices (24). Piston (16 ) is initially located above an upstream end (28) of the tubular member (14). Apparatus (10) is slid through the drill string (12) until coll ar (26) abuts a stub, typically a core bit retained at the end of the string. Fluid pressure is then applied to apparatus (10) by pumping water or mud down the drill pipe (12). This forces collar (26) to be displaced in covering the orifices (24). This allows the fluid pressure to push piston (16) through the tubular member (14) to force grease through the orifices (24) and out the downstream end of stream (12).
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