Features and application of gate valve:

A gate valve is a sliding valve with a parallel gate as a closing element. The closing element (gate) is a valve moving vertically along the axis of the channel. The closing element may be a single gate or a double gate with a brace mechanism between them. Gate to seat pressure is controlled by acting with the medium pressure of the floating gate or floating seat. In the case of a double disc flat gate valve, this tension may be supplemented by a double disc opening mechanism. Gate valves have a variety of structural forms, the main difference is the use of different sealing element structure. According to the structure of the sealing element, the gate valve is often divided into several different types, and the common forms are flat gate valve and wedge gate valve. According to the structure of the valve stem, it can also be divided into lift lever gate valve and rotary lever (blind lever) gate valve.

The advantage of gate valve is the flow resistance is small, the flow resistance is similar to the short tube. The flat gate valve with the diversion hole can be installed on the pipeline and pigging can be carried out directly with the pig. Since the gate is sliding on both seat faces, the blind stem soft-seal gate valve fluid is suitable for media with suspended particles. The sealing surface of flat gate valves is actually automatically positioned. Seat sealing surface will not be damaged by body thermal deformation. And even if the valve is closed in a cold state, the thermal elongation of the stem will not overload the sealing surface. At the same time, when the valve is closed, no guide hole plate gate valve also does not require the closing position of the gate has a higher precision, so the electric plate valve can be used to control the opening and closing position.

When the medium pressure is low, the sealing force of the metal sealing surface is not enough to achieve satisfactory sealing. On the contrary, when the medium pressure is high, if the sealing surface is not lubricated by system medium or external medium, opening and closing frequently may make the sealing surface wear too much. Another disadvantage is that a circular gate moving laterally in a circular runner is only sensitive to flow control when it is at 50% of the valve's closed position. Moreover, when the gate breaks the high speed and high density media flow, it will produce violent vibration. The seat can also be throttled if it is v-shaped and tightly guided to the gate.

In various types of valves, the application of gate valve for a wide range of, in the pipeline generally used as a cut off medium, that is, all open or all closed use. In general, gate valves cannot be used for regulating flow. Gate valves can be used for low temperature, low pressure, high temperature and high pressure, and can be used for a variety of different media according to the different material of the valve. But gate valves are generally not used to transport mud and other granular medium in the pipeline. Gate valves have many advantages and are therefore widely used. Generally, the pipeline with a diameter larger than DN50 is used as the device to cut off the medium. Gate valves are widely used in the pipeline with a small orifice. Gate valves made of forged steel are especially used in the pipeline.