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Large caliber gate valve manufacturer: the working principle of large caliber gate valve

Release Time:

Aug 21,2020

Large diameter gate valves are used to cut off or connect the medium in the pipeline through wedge gate valves and parallel gate valves. According to the sealing surface configuration, it can be divided into wedge gate valve and parallel gate valve. Wedge gate valve can be divided into: single gate, double gate and elastic gate. Parallel gate valves can be divided into single gate and double gate. There are two kinds according to the thread position of the stem: open gate valve and dark gate valve.

1. When closing the large-caliber gate valve, the sealing surface can only be sealed by the medium pressure, that is, the sealing surface of the gate is pressed to the seat on the other side by the medium pressure. Ensure that the self-sealing sealing surface is sealed. Most gate valves use a forced seal, which means that when the valve is closed, the gate must be pushed against the seat by an external force to ensure the tightness of the sealing surface. A gate valve moves linearly with the stem, which is called a riser gate valve (also known as a riser gate valve). Usually, there is a trapezoidal thread on the lift rod that passes through the nut at the top of the valve and the guide groove on the body, and the rotational motion becomes linear, that is, the operating torque becomes the operating thrust.

2. When the large-diameter gate valve is opened, when the lifting height of the gate plate is equal to 1:1 of the valve diameter, the fluid channel is completely unimpeded, but this position cannot be monitored during operation. In practical use, the apex of the stem is used as the marker, the non-movable position, as its fully open position. To account for locking due to temperature changes, it is common to open it to the apex position and then reverse the 1/2-1 turn back to the fully open valve position. Therefore, the full opening position of the valve is determined by the position (stroke) of the ram.

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