Engineers designing aerospace propulsion systems are always faced with the challenge of optimizing system performance. As program requirements increase, system design engineers survey 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. But this is usually due to misuse of equipment. Therefore, for any given application, it is important to consider all aspects of the valve.

There are many factors to consider when determining the size of a check valve; It is not sufficient or desirable to use only process pipe size. Factors such as fluid temperature, pressure, viscosity, and turbidity can affect the size of the check valve. Depending on the rigor of the application, the choice of seat material can also affect the long-term performance of check valves. Soft versus hard seating and allowable leakage (if any) under countercurrent conditions should also be considered. In rare cases, the rapid closing and opening of a valve or other downstream device can create shock waves in the fluid that can trigger check flutter. In this case, a design is needed to protect the check valve from this impact response. The all-welded construction eliminates the possibility of external leakage, even under the most demanding shock and vibration conditions.

In spring-biased check valves, quivering usually occurs when the spool opens rapidly and begins to oscillate toward the seat. Prolonged chatter can cause premature seat damage and can lead to valve leakage in countercurrent conditions. This leak prevents the check valve from working properly and must be replaced. Chatter 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 speed flows can also create conditions that cause flutter. Properly sized check valves should not vibrate under normal flow conditions. However, if the flow rate drops significantly during use, the check valve may quiver. This design inhibits the movement of the lift spool, allowing it to move to a fully open position without bouncing, or oscillate under low flow conditions where flutter may occur, thereby providing stable, flutter free operation under all flow and pressure conditions.