Swing check valves are used in the following situations:
According to the pipeline installation position
Horizontal pipeline: Swing check valves can be installed on horizontal pipelines. At this time, when the medium flows forward, the valve disc rotates around the pin shaft under the action of the medium pressure to open, allowing the medium to pass; when the medium flows in the reverse direction, the valve disc closes under the action of its own weight and the pressure of the countercurrent medium to prevent the medium from flowing back.
Vertical pipeline: When installed on a vertical pipeline, the medium must flow from bottom to top. Because the closing torque of the valve disc is generated by its gravity, if the medium flows from top to bottom, the closing torque of the valve disc is very small when it is in the fully open position, and the valve will be delayed in closing, which may not effectively prevent the medium from flowing back.
According to the size of the pipeline diameter
Large and medium diameter pipelines: The flow channel inside the swing check valve is basically a straight line, and the flow resistance is smaller than that of the lift check valve. It is suitable for large and medium diameter occasions. For example, the single-flap swing check valve is suitable for large and medium diameters. Large-diameter single-flap swing check valves mostly adopt a slow-closing structure, which can reduce the water hammer phenomenon of the medium. The nominal diameter is generally DN50-DN600; double-flap swing check valves are also suitable for large and medium diameters. The double-flap swing check valve with a short structure length and light weight can also adopt a slow-closing structure. The nominal diameter can reach DN50-DN1200; multi-flap swing check valves are suitable for low-pressure and extra-large diameter pipelines, and the nominal diameter is DN800-DN1800.
By working pressure and temperature
High-pressure and high-temperature environment: Swing check valves can be made into very high working pressures, with a nominal pressure of up to 42 MPa. Moreover, depending on the material of the shell and seal, they can be used for any working medium and any working temperature range. The working temperature range of the medium is between -196℃-800℃, and can be used in high-temperature and high-pressure industrial scenes, such as steam pipes in thermal power plants.
Low-pressure and normal-temperature environment: In some low-pressure and normal-temperature pipeline systems, such as urban water supply and drainage systems, swing check valves can also play a role in preventing the backflow of media and ensuring the normal operation of the system.
By medium type
Clean media: Swing check valves are suitable for clean media such as water, oil, steam, and gas. These media will not cause serious wear and corrosion to the valve disc and valve seat, and can ensure the normal operation and long service life of the check valve.
Corrosive media: By selecting suitable materials, such as stainless steel, corrosion-resistant alloys, etc., swing check valves can also be used in pipelines of some corrosive media, such as pipelines for the transportation of corrosive media such as acids, alkalis, and salts in the chemical industry.