The main function of the gate valve is to cut off the flow of the medium in the pipeline. In the pipeline system, when a certain section of the pipeline needs to be inspected, maintained or replaced, the gate valve can be closed to isolate the section of the pipeline from other parts, prevent the medium from continuing to flow, and ensure safe operation. For example, in the urban water supply pipeline, when the pipeline in a certain area needs to be repaired, the water flow can be cut off by closing the corresponding gate valve.
In addition, the gate valve can also be used to adjust the flow in some cases. Although it is usually not used as the main flow regulating valve, in some occasions where the flow control accuracy is not high, a certain degree of flow regulation can be achieved by adjusting the opening height of the gate. For example, in some small irrigation systems, the flow of irrigation water can be controlled by slightly opening the gate valve.
In some special pipeline systems, the gate valve can also be used in conjunction with the check valve to prevent the medium from flowing back. When the medium in the pipeline has a tendency to flow back, the gate valve can be closed in time to prevent the medium from flowing back and protect the safety of the equipment and pipeline system. For example, in some sewage discharge systems, it prevents sewage from flowing back to the sewage treatment equipment.
The structural features of the gate valve include its disc being a gate type, and it is usually installed on pipes with a diameter greater than 100mm. The gate valve has the advantages of labor-saving opening and closing and low flow resistance, but the sealing surface is prone to wear and leakage, the opening stroke is large, and maintenance is difficult. The gate valve cannot be used as a regulating valve and must be in the fully open or fully closed position.