The working principle of gate valve and its application
The working principle of gate valve is based on the linear motion of valve plate. Gate valve is mainly composed of valve body, valve plate, valve stem, valve seat and driving device. When a driving device, such as a manual handwheel, an electric actuator or a pneumatic actuator, exerts a force on the valve stem, the valve stem will drive the valve plate to move linearly up and down along the guide of the valve seat. When the valve plate is completely lowered to the sealing surface of the valve seat and tightly attached, the gate valve is in a closed state, at which time the fluid is completely cut off and cannot pass. When the valve plate is lifted away from the sealing surface of the valve seat and reaches a certain height, the gate valve is in an open state and the fluid can flow freely in the valve body. Compared with butterfly valves which adjust the flow by rotating the valve plate, gate valves are generally suitable for full-open or full-closed conditions, and are seldom used for accurate flow adjustment, because in the partially-opened state, the gate is greatly washed and impacted by the fluid, which is easy to cause wear and deterioration of sealing performance.
Gate valves are widely used in many fields. In the water supply and drainage system, it is often used at the raw water inlet of urban waterworks to control the on-off of water flow in the water source introduction stage, so as to ensure that the waterworks can cut off the water source under the conditions of equipment maintenance and overhaul. Gate valves are also widely used in midway nodes of long-distance water pipelines and key positions of urban water supply main network, so that when the pipeline fails or is maintained, the water flow can be quickly cut off and the water cut-off scope can be narrowed. In the sewage treatment plant, gate valves are used for the inlet and outlet pipes of each treatment unit to control the flow direction and treatment process of sewage.
In the oil and gas industry, gate valves are used in wellhead devices, which can control the exploitation and transportation of oil and gas flow at the initial stage of oil and gas exploitation. In the gathering and transportation pipeline, when the pipeline needs to be maintained and overhauled in sections, or in case of emergency, the gate valve can quickly cut off the oil and gas to ensure the safety of the pipeline system. In refineries and chemical plants, gate valves made of special materials (such as high-temperature alloy and corrosion-resistant stainless steel) will be used for high-temperature, high-pressure and corrosive medium pipelines, such as pipelines for various oil products in the process of petroleum refining and pipelines for corrosive materials such as acid and alkali in chemical production, so as to ensure stable operation under harsh working conditions.
In the electric power industry and thermal power field, gate valves are used in the water supply pipeline of boilers to provide stable water supply for boilers, and the water supply can be cut off in time when the boilers need to be overhauled or maintained. In the hydropower industry, the gate valve can control the water flow into the water turbine in the diversion pipeline of hydropower station. When the water turbine fails or needs maintenance, the water flow is cut off by closing the gate valve. In the field of nuclear power, gate valves are used in key parts such as cooling system pipelines of nuclear islands and conventional islands. Because of the high safety requirements of nuclear power systems, the design, manufacture and installation of these gate valves need to follow strict standards and specifications to ensure reliable operation under various working conditions and ensure the safe and stable operation of nuclear power plants.
Have Any Questions? Get in Touch with Us Now!