Analysis and Failure Prevention of Nozzle Check Valves Used for Protection of Rotating Equipment Due to Wear and Tear in the Oil and Gas Industry

This paper reviews the most common type of check valves: swing, dual plate and nozzle. The pros and cons of each choice will be explained in this review, which can be used as a basis for making the most suitable check valve selection for installation after rotating equipment such as pumps and compressors. Dual plate check valves are compared to nozzle check valves in terms of pressure drop and water hammering. The process and valve information in two case studies are based on two recent Norwegian offshore projects. Dual plate check valves show more than twice the pressure drop and more than three times the water hammering effect in the form of applied pressure to the piping system compared to nozzle check valves. Thus, nozzle check valves are proposed as the best choice for use after pumps and compressors. The most important risk that causes nozzle check valve failure during operation is chattering; this occurs when the fluid can not keep the valve in fully open position and causes wear and tear inside the valve. The second case study of a nozzle check valve in a recent Norwegian project is reviewed in which the minimum flow in the piping system can not fully open the valve. Different solutions such as reducing the size of the valve, reducing the spring torque behind the valve seat and increasing the minimum flow are proposed in this paper. In addition, high fluid velocity is considered as another operational problem that leads to wear and tear of the valve as well as valve failure. Adjusting the narrow area inside the nozzle check valves can reduce the velocity inside the valve to an acceptable limit.