Globe valve is truncated class, one of the most widely used in valves; valve widely used in various types and different parameters on pressure pipeline, has many advantages, such as: in the process of opening and closing, the cut-off valve sealing surface and the valve seat sealing surface, no sliding friction between friction is much smaller than gate valves, more resistant to wear and abrasion; Simple structure, convenient manufacturing and maintenance; The opening height is also much smaller than the gate valve and has significant advantages in applications where installation height is limited. However, due to the large force of the opening and closing of the globe valve, the required thrust of the driving device is large; At the same time, the length of the structure is long, the valve is large, and the manufacturing cost is high. Therefore, in all kinds of high-pressure, large-diameter pipelines, the application of the globe valve is relatively small. To meet the market demand, expand the globe valve in high pressure, large diameter pipeline applications, the design and development of the double disc type globe valve.
Medium of initial conditions, the valve closed pipe into the valve body, with big holes on the disc into the disc lumen, start the drive, the stem drive small disc first open, open the seal, medium through a small disc, the valve on both ends of the differential pressure decreases rapidly, continue to open small disc until fully open) (about a third of the valve, the valve stem continues to rise to drive the disc open, open the seal, and valve fully open. The stem force of the force needed to open a small disc and the function of the medium on the large disc force (gravity negligible), the small disc opens, the pressure differential between the valve import and export decrease (mainly depends on sealing area ratio between inside and outside), the open large disc, medium forces acting on the large disc far less directly using single disc medium forces acting on the disc, the valve stem of total force decreases, and the stem diameter smaller, lumen size smaller, the overall structure of the valve is reduced, the weight, and at the same time open the valve drive thrust decreases, and at the same time reduces the valve and a driving gear manufacturing costs, Improve the use economy of the valve to achieve the purpose of energy saving.
