Experimental investigation of check valve behaviour during the pump trip

The paper is focused on the description of an experimental investigation of a nozzle check valve. Attention is paid to the behaviour during transitions when the flow is decelerating. Flow reversal is often accompanied with the check valve slam, because the check valve closes with a delay after the flow changes its direction. The maximal back flow velocity determines the maximal pressure peak when the check valve closes, so this velocity was found for different flow decelerations.