The single plate check valve is automatically held in a middle position by the flange connection bolts and hex nuts. It uses a swinging plate to prevent return flow in the piping system. The valve design allows them to be fitted in a tight space.

The flow is restricted within the valve body because the flange connection is in place and there is not much room for the plate to open in the pipeline. The valve requires a low opening pressure to allow fluid to flow through. The valve is at the closing position and sealed with O-ring if the initial pressure is higher than the entrance pressure.