| 摘要 |
<p>Pulser connected to the drill string is coupled at the bottom end to the chisel bit and contains a mud entry channel, first pulse or surge channel supplied from the entry channel and a port above the inlet to force the mud out. A second pulse channel supplied from the entry channel covers the annular space up to this port and a rocker valve is used to cut off the channels alternately, producing a negative pulse in the closed channel. A spindle in the pulser is connected to part of the pulser so as to pass torque to the bit. The spindle has the inlet to the second surge channel so that when the valve engages the spindle it closes the inlet to produce a pressure drop abobe the valve. This produces via the negative pulse, a downwards thrust on the spindle and this on the chisel bit. Higher penetration, improved drillings removal in the form of large splinters.</p> |
