Check valves are suitable for gas. The following is a detailed introduction:
Working principle: Check valves rely on the power of the fluid itself, the deadweight of the valve disc, and the pressure of the spring. When the fluid flows forward, the valve disc is pushed open and the fluid can pass smoothly; when the fluid tries to flow back, the valve disc will quickly close to prevent the fluid from flowing in the opposite direction. Gas, as a fluid, also follows the principles of fluid mechanics. Check valves can use the flow pressure and characteristics of the gas to achieve one-way flow control and prevent gas backflow.
Practical application cases
Compressor outlet: Check valves are usually installed on the outlet pipe of the compressor. The compressor compresses the gas and discharges it. The check valve prevents the gas from flowing back to the compressor when the compressor stops running or fails, protecting the compressor from damage. At the same time, it also avoids problems such as system pressure fluctuations caused by gas backflow in the pipeline.
Ventilation system: In the ventilation system of factories, buildings, etc., check valves are used to control the flow direction of air. For example, installing a check valve on the exhaust duct can ensure that air can only be discharged from indoors to outdoors, preventing outdoor air from flowing back into the room, and ensuring indoor air quality.
Gas transmission pipeline: In long-distance gas transmission pipelines, check valves can be installed at key locations, such as pump station outlets, distribution stations, etc. When abnormal conditions occur in the gas transmission in the pipeline, such as when the pump stops running or the pipeline ruptures, the check valve can be closed in time to prevent gas reflux, avoid damage to the pipeline system, and ensure the safety and stability of gas transmission.
Applicability of different types of check valves to gas
Swing check valve: The valve disc is disc-shaped and rotates around the rotating axis of the valve seat channel. Because the channel inside the valve is streamlined, the flow resistance is smaller than that of the lift check valve. It is suitable for large-caliber occasions with low flow rate and infrequent flow changes, but it is not suitable for pulsating flow, and its sealing performance is not as good as the lift check valve. It can be used in pipeline systems with relatively stable gas flow and small pressure changes.
Lift check valve: The valve disc slides along the vertical center line of the valve body and can only be installed on horizontal pipelines. The valve disc on the high-pressure small-caliber check valve can be a ball. It is suitable for occasions where the gas flow changes greatly and the sealing performance needs to be strictly controlled, such as some chemical gas transmission pipelines with high requirements for gas leakage.
Butterfly check valve: The disc rotates around the pin in the valve seat. It has a simple structure and can only be installed on horizontal pipes. It has poor sealing performance. It is suitable for low-pressure, large-diameter gas pipelines, such as some branch pipelines in urban gas pipelines.
