Operating torque of various valves

If the valve actuator is too small, the side cannot generate enough torque to fully operate the valve. Generally speaking, we believe that the required valve operating torque comes from the friction between the metal components of the valve (such as the ball core, valve disc) and the sealing components (valve seat). Many factors, such as valve usage, operating temperature, operating frequency, pipeline and pressure difference, and flow media (lubrication, drying, mud), all affect the valve operating torque.

Ball valve operating torque

The structural principle of a ball valve is basically based on a polished ball core (including a channel) sandwiched between two valve seats (upstream and downstream). The rotation of the valve core intercepts or flows through the ball core, and the force generated by the pressure difference between the upstream and downstream makes the ball core tightly against the downstream valve seat (floating ball valve structure). The torque required to operate the valve in this situation is determined by the friction between the ball core and valve seat, as well as between the valve stem and packing. The maximum torque occurs when a pressure difference occurs and the ball core rotates in the open direction from the closed position.

Butterfly valve operating torque

The structural principle of a butterfly valve is basically based on the butterfly plate fixed on the axis. In the closed position, the butterfly plate is completely sealed with the valve seat. When the butterfly plate rotates (around the valve stem) parallel to the flow of fluid, the valve is in the fully open position. On the contrary, when the butterfly plate is perpendicular to the flow of fluid, the valve is in the closed position. The torque for operating a butterfly valve is determined by the friction between the butterfly plate and the valve seat, as well as between the valve stem and the packing. At the same time, the force exerted by the pressure difference on the butterfly plate also affects the operating torque. The valve has the maximum torque when closed, and after a slight rotation, the torque will significantly decrease.

Operating torque of plug valve

The structural principle of the plug valve is based on the plug sealed in the conical plug body. There is a channel in one direction of the plug of the plug valve. As the plug is screwed into the valve seat, the valve opens and closes. The operating torque is usually not affected by the pressure of the fluid, but is determined by the friction between the valve seat and the plug during the opening and closing process. The plug valve has the maximum torque when closed. Due to the influence of pressure, a high torque is maintained throughout the remaining

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