It is a single direction valve. Generally it is used to prevent the flow of a medium in reverse direction. It is used to prevent damage to equipment or system, by preventing the reverse flow of the medium. It is exclusively used for the pumps and compressor for the fluids and gases respectively.
It is operated by the flow of the medium and do not require the energy from outside. It is also used as a safety valve for different system. They maintain the pressure by preventing the backflow of the medium. They can be used for the backup in the system, in case of failure of the pumps and on exceeding the pressure of the system.
Swing check valves are available with different design as per use. These valves contain very low turbulence and pressure drops. It contains easy opening due to its angled surface. it automatically closed on decreasing pressure of the flow.