The design engineers of aerospace propulsion systems are always faced with the challenge of optimizing system performance. As program requirements increase, system design engineers investigate the industry to determine the availability of components that can improve system performance. One area for improvement is the check valve.

Check valves prevent backflow of process media in hydraulic, propellant, and oxidizer systems. There is a problem with the check valve in operation. However, this is usually caused by misuse of equipment. Therefore, it is important to consider all aspects of the valve for any given application.

There are many factors to consider when determining the size of check valve; It is not enough or desirable to use only the size of process pipeline. Fluid temperature, pressure, viscosity, turbidity and other factors will affect the check valve size. Based on the severity of the application, the selection of the seat material will also affect the long-term performance of the check valve. The allowable leakage (if any) under the condition of soft seat and hard seat as well as reverse flow shall also be considered. In rare cases, rapid closure and opening of valves or other downstream equipment can create shock waves in the fluid, triggering check valve chatter. In this case, a design is required to protect the check valve from this impact force. All welded construction eliminates the possibility of external leakage, even under severe impact and vibration conditions.

In spring biased check valves, chatter usually occurs when the spool opens rapidly and begins to oscillate toward the seat. Prolonged chatter can lead to premature valve seat failure and valve leakage under reverse flow conditions. This leakage makes the check valve unable to work properly and must be replaced. Flutter is also often the result of oversized check valves because there is not enough flow to lift the spool away from its seat during normal operation. High velocity flow can also create conditions that cause flutter. Under normal flow conditions, check valves of appropriate size shall not vibrate. However, if the flow rate drops significantly during use, the check valve may vibrate. This design can inhibit the movement of the lift spool, so that it can move to the fully open position without bouncing, or oscillate under low flow conditions that may cause flutter, thus providing stable, flutter free operation under all flow and pressure conditions.