There are the following differences between double-plate wafer check valve and swing check valve:
Structural form
Double-plate wafer check valve: The valve disc is usually two semicircular shapes, similar to butterfly wings, and the valve is clamped between two flanges during installation.
Swing check valve: The valve disc is disc-shaped and rotates around the rotating shaft of the valve seat channel. The back of the valve disc is fixedly installed on one end of the rocker through a connecting screw and a nut, and the other end of the rocker is hingedly installed on the bracket of the inner cavity wall of the valve body.
Working principle
Double-plate wafer check valve: When the medium flows forward, the fluid pressure pushes the valve disc to open and allow the fluid to pass; when the medium flows back, the valve disc automatically closes under the action of the spring or fluid pressure to prevent the medium from flowing back.
Swing check valve: The medium pushes the valve disc to rotate and open. When the medium flows back, the valve disc automatically closes by its own gravity or reverse fluid pressure.
Fluid resistance
Double-plate wafer check valve: The fluid resistance is relatively small, because after the valve disc is opened, the fluid channel is relatively smooth and there is no obvious obstruction.
Swing check valve: Since the valve disc rotates to open and close, the fluid resistance when the medium passes through is also small, but it may be slightly larger than the double-plate wafer check valve, because its valve disc may cause some disturbance to the fluid during the rotation process.
Installation method
Double-plate wafer check valve: It adopts wafer installation, that is, the valve is clamped between two flanges, which is easy to install and does not require additional support, which can save installation space.
Swing check valve: It usually adopts flange connection or wafer connection. The installation position is not restricted and can be installed on horizontal, vertical or inclined pipelines, but attention should be paid to the flow direction of the medium during installation.
Applicables
Double-plate wafer check valve: It is suitable for large-flow, low-pressure systems, commonly used in water supply and drainage, fire protection, HVAC and other fields, and can also be used in some places with high space requirements.
Swing check valve: It is suitable for large-diameter pipelines and can be used in various occasions from low pressure to high pressure, such as petrochemical, electric power, metallurgy and other industries, especially for pipelines with large flow, low flow rate and infrequent flow changes.
Sealing performance
Double-plate wafer check valve: The sealing performance is good, the contact between the valve disc and the valve seat is relatively close, which can effectively prevent the leakage of the medium.
Swing check valve: The sealing performance is relatively poor, and the sealing surface between the valve disc and the valve seat may be worn after long-term use, resulting in a decrease in sealing performance.
Maintenance
Double-plate wafer check valve: The structure is relatively simple and the maintenance is relatively convenient. The main inspection is the sealing condition of the valve disc and the valve seat and the elasticity of the spring.
Swing check valve: It is necessary to regularly check the sealing of the valve disc and the valve seat, the wear of the rocker and the pin shaft, etc. to ensure the normal operation of the valve.