Silencer check valves are automatic valves that open and close their disc valves automatically due to the flow of the medium, used to prevent backflow of the medium. They are also known as non-return valves, one-way valves, silencer check valves, backflow check valves, and back pressure valves. Check valves are a type of automatic valve primarily used to prevent backflow, prevent pumps and driving motors from reversing, and to release the medium in containers. They can also be used on pipelines that supply auxiliary systems where the pressure may rise above the system pressure. Check valves are mainly divided into swing check valves (rotating around the center of gravity) and lift check valves (moving along the axis).

An anti-siphon valve is a valve that automatically opens and closes its disc based on the flow of the medium itself, used to prevent reverse flow of the medium, also known as a non-return valve, one-way valve, anti-siphon non-return valve, and back pressure valve. The check valve is a type of automatic valve, primarily used to prevent reverse flow of the medium, prevent pumps and driving motors from reversing, and to release the medium in the container. Check valves can also be used on pipelines that supply auxiliary systems where the pressure may rise above the system pressure. Check valves can mainly be divided into swing check valves (rotating around the center of gravity) and lift check valves (moving along the axis). Internal threaded check valves and butterfly check valves belong to this type, which includes swing check valves and lift check valves. Swing check valves have a hinge mechanism and a valve disc that sits freely on the inclined surface of the valve seat. To ensure the valve disc reaches the correct position on the valve seat surface each time, the valve disc is designed within the hinge mechanism, allowing sufficient swing space and ensuring the valve disc makes a true, full contact with the valve seat. The valve disc can be made entirely of metal, or it can be inlaid with leather, rubber, or use synthetic coatings, depending on the performance requirements. In the fully open position, the fluid pressure is almost unobstructed, resulting in a relatively small pressure drop through the valve. Lift check valves have the valve disc seated on the valve body's seat sealing surface. This valve, besides the valve disc being able to rise and fall freely, operates similarly to a gate valve, where the fluid pressure lifts the valve disc from the seat sealing surface, and reverse flow of the medium causes the valve disc to fall back onto the seat and cut off the flow. Depending on the operating conditions, the valve disc can be a full metal structure or have rubber pads or rings镶嵌ed on the valve disc架. Like a gate valve, the fluid passage through the lift check valve is narrow, so the pressure drop through a lift check valve is greater than that of a swing check valve, and the flow of a swing check valve is less restricted. This type of valve should generally be installed horizontally in the pipeline.