| 摘要 |
A pressure pulse generator to generate pressure signals in drilling fluid for transmission to surface comprising: an outer housing (100) having an inlet (9) and an outlet for supply to the drilling assembly (59); a control element (10) slidably mounted in the housing (100) for opening and closing said inlet (9), said element being operative to generate a pressure pulses when it closes; a control passage (26, 27, 28) extending through the element (10) and closable by a valve element (36) arranged to be exposed to the pressure in the passage; and an actuator assembly (13, 14, 15, 17, 19, 21, 35, 36, 37) connected to the control element (10). The control element moves upon activation (10) relative to the inlet to generate a pulse. When deactivated, it blocks the flow through the passage (26, 27, 28) so that all of the fluid bypasses via the inlet.
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