摘要 |
<p>A flushing system for supplying compressed flushing air to a drill string for flushing cuttings during a drilling operation includes an air compressor having an inlet valve at the compressor inlet, and a turnvalve at the compressor outlet. Those valves are biased to a normal state, but when actuated, the inlet valve is to reduce the inlet air volume, and reduce the outlet air volume and pressure. If flushing air conducted to the drill string is temporarily reduced or terminated, while the compressor continues to operate, air pressure builds up and is conducted to both the inlet valve and turnvalve for reducing the volume and pressure of air emitted from the compressor outlet. In this way, the energy required to operate the compressor is significantly reduced.</p> |