The valve is opened or closed by the valve disc to rotate around the spindle outside the valve seat; and it is an automatic valve when it is automatically opened or closed by the force generated by the medium flowing within the pipeline. Its major function is to prevent the backflow of the medium in the pipeline, reverse rotation of the pump and its driving motor, and discharge of the medium in the container.

The valve is opened/closed by the valve disc moving in a direction parallel to the valve seat hole axis and can only be installed on horizontal pipelines with the major function of preventing medium backflow when shutting down the pump and maintaining the water column required by pumping.

Two arch disc are fixed onto the valve body with a spindle on which two torsional springs are equipped for installing the butterfly plate onto the valve body sealing face. The butterfly plate pressed by the springs is opened by relying on the medium pressure, and the valve is closed by the spring force and the medium pressure under backflow. It can be installed on horizontal and vertical pipelines.

It is opened or closed by the valve clack moving to-and-fro through the valve body guiding axle under the spring effect. The valve body passageway is designed in a wing-shaped streamline type, allowing the medium to flow through the passageway rapidly and steadily with no noise. It can be installed on horizontal and vertical pipelines.

The pressure seal valves are designed in accordance with BS1868 and ASME B16.34 for service of high temperature and high pressure and are widely used in fossil fuel power plant. Compared with bolted bonnet joint valves, it provides absolute reliable sealing of the bonnet joint, so that the pressure seal valves are more compact and rigid as well as maintenance cost-effective at high temperature and high pressure service. It is an automatic valve when it is automatically opened or closed by the force generated by the medium flowing within the pipeline. Its major function is to prevent the backflow of the medium in the pipeline, reverse rotation of the pump and its driving motor, and discharge of the medium in the container.