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Gate Valve Installation and Usage
A gate valve is a type of shut-off valve, but its sealing performance is not as good as that of a globe valve. The primary "responsibility" of a gate valve is to completely stop the flow, while allowing fluid to continue flowing with *minimal resistance*. However, it is not suitable for precisely controlling the flow rate or pressure of the medium. If used continuously for throttling purposes over an extended period, the sealing surfaces can easily become eroded and worn by the flowing media, compromising their ability to maintain a tight seal.
Release date:
2021-11-12
1. Gate valves are shut-off valves, but their sealing performance is not as good as that of globe valves. The primary "responsibility" of a gate valve is to completely stop the flow while allowing fluid to continue flowing with *minimal resistance*. However, they are not suitable for precisely regulating the flow rate or pressure of the medium. Prolonged use in adjustment mode can cause the sealing surfaces to erode and wear due to the abrasive action of the medium, compromising their ability to maintain a tight seal. Additionally, operators should pay close attention to the temperature and pressure ratings of the medium, as these factors directly impact the valve's reliability. At high temperatures and pressures, thermal expansion or contraction may lead to the gate becoming stuck in the closed position. This issue is particularly pronounced in wedge-type gate valves.
2. Gate valves can be installed on either horizontal or vertical pipelines. However, single- or double-disc gate valves must be mounted horizontally, with the handwheel positioned above the valve—downward installation is strictly prohibited. Additionally, there are no restrictions on the direction of media flow through the gate valve. Typically, gate valves are connected via flanges, though welded connections may also be used in certain special applications.
3. For large-diameter and high-pressure gate valves, the operating torque required for opening and closing is relatively high. To reduce this torque, an alternative method is to install a bypass valve. The bypass valve is mounted externally to the main gate valve, with its inlet and outlet connected in parallel—directly to either side of the main valve. Before opening the main gate valve, first open the bypass valve to equalize the pressure difference across the valve’s disc, thereby minimizing the opening torque of the main gate valve. The selection of the bypass valve’s diameter should be carefully determined based on the main valve’s size and the specific application requirements.
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