Multiple Activation Bypass Valve

During a drilling operation， when the well kick has taken place and the bit bore is blocked. The by-pass valve can be opened to go fluid circulation and well killing. Before drilling in flow gas formation, the by –pass valve shall be located near or on the bit.

When take place well kick and pump pressure is too high or blocked， the following steps can be taken to open the by-pass valve :

1. Discharge Kelly and drop in a steel ball (or a Nylon ball) which is carried by tool;

2. Connect with Kelly;

3. Put the ball into retainer by pump circulation;

4. When fluid is closed， the shear pin can be sheared off by adding 0.5~1.5Mpa pump pressure than the original pump pressure;

5. After the pin is sheared， the seal sleeve moves down to open the discharge hole and pump pressure comes to drop down, then normal circulation and well-killing operation can be started.