The difference between parallel gate valve and wedge gate valve

What is a parallel gate valve: that is, the sealing surface is parallel to the vertical centerline, so the valve body and the sealing surface on the gate are also parallel to each other. The most common type of this kind of gate valve is the double gate type. In order to make the valve body and the two sealing surfaces of the gate closely contact when closing, a double-sided thrust wedge is often sandwiched between the two gates. In this way, when the valve is closed, the contact between the double-sided thrust sub-block and the bottom of the valve body is gradually stressed, and the double gate is pushed open so that the sealing surface of the gate and the valve body are sealed and tightly attached. This kind of double gate parallel gate is mostly used in low pressure pipelines such as small pipelines. Parallel gate valves with single gate are also available but rare.

Wedge gate valve has single and double gates. The advantage of the double gate type is that the accuracy of the sealing and the angle is lower, the temperature change is not easy to make the gate wedge, and the gasket can be added to compensate for the wear of the sealing surface. The disadvantage is that the structure is complicated, and it is easy to stick in dry medium, and more importantly, the gate plate is easy to fall off after the upper and lower baffles are corroded for many years. Although the single gate has the disadvantages of high sealing and high angular accuracy, difficult processing, and temperature changes may cause the gate to be wedged, it is simple in structure and reliable in use. Elastic deformation is used to compensate for the deviation generated in the angle processing of the sealing surface, so it is widely used at present.

Post time: Mar-08-2022