Utmost Flow Control Technology Co., Ltd.
Utmost Flow Control Technology Co., Ltd.

Installation and Maintenance of Gate Valve

1. The installation and maintenance matters of the gate valve

(1) The handwheel, handle and transmission mechanism are not allowed to be used for lifting, and collision is strictly prohibited.

(2) The double gate gate valve should be installed vertically (that is, the valve stem is in the vertical position and the handwheel is on the top).

(3) The gate valve with the bypass valve should open the bypass valve before opening (to balance the pressure difference between the inlet and outlet and reduce the opening force).

(4) The gate valve with transmission mechanism shall be installed according to the provisions of the product instruction manual. If the valve is frequently used, lubricate it at least once a month.

2. The gate valve is used as a cut-off medium

When the gate valve is fully open, the entire flow is straight, and the pressure loss of the medium is minimal at this time. Gate valves are usually suitable for conditions that do not require frequent opening and closing, and keep the gate fully open or fully closed. Not intended for use as regulation or throttling. For high-speed flowing media, the gate can cause vibration of the gate when it is partially opened, and the vibration may damage the sealing surface of the gate and the valve seat, and the throttling will cause the gate to be eroded by the medium. From the structural form, the main difference is the form of the sealing element used. According to the form of the sealing element, the gate valve is often divided into several different types, such as: wedge gate valve, parallel gate valve, parallel double gate valve, wedge double gate gate valve, etc.

3. The most commonly used forms are wedge gate valves and parallel gate valves

The sealing surface of the parallel gate valve is parallel to the vertical centerline, so the sealing surfaces of the valve body and the gate plate are also parallel to each other. This kind of gate valve is common with double gate type. In order to keep the valve body and the two sealing surfaces of the gate tightly in 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 wedge and the bottom of the valve body is gradually stressed, and the double gates are 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 valve is mostly used in low pressure pipelines such as small pipelines.

The sealing surface of the wedge gate valve forms a certain angle with the vertical center line. It is required that the inlet valve with higher temperature of the medium should have a larger inclination angle to reduce the possibility of wedging the gate plate when the temperature changes. Wedge gate valve has single and double gates. The advantage of the double gate type is that the precision of sealing and angle is low, and the temperature change is not easy to wedge the gate. The wear of the sealing surface can be compensated by adding a gasket. Especially after changing to elastic gate. Elastic deformation can be produced to compensate for the deviation in the angle processing of the sealing surface.

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