Silent check valve is a kind of valve that automatically opens and closes the valve flap by relying on the flow of the medium itself to prevent the backflow of the medium. It is also known as check valve, one-way valve, backflow valve, and back pressure valve. Its main characteristics and advantages are as follows: 

 I. Structural characteristics 

 1. Automatic operation: The silent check valve is an automatic valve that does not require an external power source, and automatically opens and closes the valve flap by relying on the pressure of the medium flow. 

 2. Various types: Silent check valves can be mainly divided into rotary check valves (rotated according to the center of gravity) and lifting check valves (moving along the axis). 

 3. Reliable sealing: A linear sealing structure is adopted between the valve flap and the valve seat of the silent check valve to ensure that the medium can effectively cut off the flow when it flows in reverse and prevent leakage. 

 II. Performance characteristics 

 1. Silent effect: The silent check valve adopts a special design, such as streamlined internal channel, short-stroke valve flap opening and closing, etc., so that the noise generated during the shutdown process is extremely small, forming a silent sound effect 2. Fruit. Fluid flow is smooth: The internal flow channel of the silent check valve is reasonably designed, and the fluid can remain smooth when passing, and the local water head loss is small, which improves the efficiency of the system. 

 3. Small pressure loss: Due to the streamlined design of the internal flow channel and the short opening and closing stroke of the valve flap, the pressure loss generated by the silent check valve during the opening and closing process is relatively small. 

 4. Strong applicability: Silent check valves can be used in a variety of occasions such as water supply and drainage, fire protection, HVAC systems, etc., especially in situations where it is necessary to prevent backflow of media and damage caused by water hammers to the pump. 

 III. Other characteristics 

 1. Small size and light weight: The silent check valve has a compact structure, small size and light weight, which is convenient for installation and maintenance. 

 2. Anti-corrosion coating: The inner and outer surfaces of some silent check valves are sprayed with non-toxic epoxy electrostatic spraying, which has good anti-corrosion performance and prolongs the service life of the valve. 

 3. Safe and reliable: The silent check valve can effectively prevent the backflow of the medium, prevent the reversal of the pump and drive motor, and the release of the container medium, which improves the safety of the system. 

 However, silent check valves also have certain limitations. For example, they should not be used in media containing solid particles and high viscosity. In addition, during installation and use, it is necessary to comply with relevant standards and specifications, and carry out regular inspection and maintenance to ensure its reliability and safety. 

 In general, silent check valves have been widely applied and recognized in many fields with their unique structure and performance advantages.