Gate Valve

Gate Valve


Topper provides superior gate valves in different sizes, types and standards, including wedge gate valves, pressure seal gate valves, knife gate valves, flat gate valves and bellows seal gate valves. A gate valve, also known as a sluice valve, is a valve that opens by lifting a barrier (gate) out of the path of the fluid. Gate valves require very little space along the pipe axis and hardly restrict the flow of fluid when the gate is fully opened. Gate valves are used to shut off the flow of liquids rather than for flow regulation. When fully open, the typical gate valve has no obstruction in the flow path, resulting in very low flow resistance. Gate valves are mostly used with larger pipe diameters (from 2" to the largest pipelines) since they are less complex to construct than other types of valves in large sizes. Gate valves can be divided into different types by seal part modes, such as wedge gate valve, plate gate valve, parallel 2-flashboard gate valve, wedge 2-flashboard gate valve. Gate valves are usually used under particular working conditions in which the valved are not opened or closed frequently, and support flashboard fully open or fully closed. They are not suitable for adjustment or throttling. Concerning pipeline transport, gate valves may be selected for transporting oil, urea, water, steam, oxidant, natural gas, nitric acid and acetic acid, depending on different materials used.

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.


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