This series belongs to the pilot valve piston valve. From the main valve and pilot valve composed of two parts. Mainly by the main valve seat, the main valve plate, piston, springs and other parts. Mainly by the pilot valve seat, disc, diaphragm, spring, adjusting SPRINGS. This product is based on the common valve made a great improvement, increased piston area, changing the throttle structure. Changed the seal in the form, and so increase the flow area, resulting in increased sensitivity, flow, life and other areas has greatly improved the performance. 
 This product is mainly used for steam pipeline for flow of large flow changes, variation in inlet pressure steam pipe.