Flanged swing check valve China also known as a non-return valve, or one-way valve. It is used to allow water to flow through it in only one direction. It works automatically without any external control. The disc swings off the seat to permit forward flow or swings on the seat to block reverse flow. It typically applies to the fire pipelines between the water main and private fire service systems, or at the fire pumper connections.Universal fire Protetion Provides at reasonable cost.