The function of square drill pipe plug valve/Kelly Cock

The square drill pipe plug valve (Kelly Cock) plays a vital role in drilling operations, and its main functions are as follows:

1. **High-Pressure Sealing**:

   - The square drill pipe plug valve, as a manual control valve in the drill string circulation system, can achieve sealing under high-pressure conditions to prevent the leakage of drilling fluid.

2. **Blowout Control**:

   - It is one of the effective tools for preventing blowouts and kicks, used to close off the central through-hole of the drill string and配套 with the wellhead blowout preventer to prevent well fluids from spraying up along the drill pipe.

3. **Easy Operation**:

   - The square drill pipe plug valve is simple to operate; turning it 90 degrees with a specialized wrench according to the instructions can open or close it.

4. **Preventing Catastrophic Accidents**:

   - To avoid catastrophic blowouts during drilling operations, square drill pipe plug valves should be connected at both ends of the drill pipe.

5. **Blowout Prevention Tools**:

   - The square drill pipe plug valve is a type of internal blowout prevention tool that can close the upper plug valve to prevent the bursting of water hoses when a well kick or blowout occurs.

6. **Structure and Sealing**:

   - The square drill pipe plug valve includes both the upper and lower valves, which are turned on and off by a specialized wrench. The sealing is achieved through the rigid配合 of a spherical valve body and a spherical valve seat, with auxiliary rubber sealing.

7. **Responding to Emergencies**:

   - During drilling operations, the plug valve is kept open. In case of a kick or well surge, to prevent drilling fluid from surging up along the water eye of the drill pipe, the plug valve must be immediately closed to prevent a blowout.

8. **Maintaining Drilling Safety**:

   - The square drill pipe plug valve can be used as a safety measure during drilling operations, such as when water hoses or high-pressure manifolds are damaged.

In summary, the main function of the square drill pipe plug valve is to ensure fluid control and safety during the drilling process, preventing blowouts and other catastrophic accidents.