The subject matter disclosed herein relates to a check valve and in particular to a check valve having a damper to reduce or prevent damage to the valve due to high speed closure rates.
Flapper or check valves are used in a wide variety of applications such as in air handling units for example. The valve operates on pressure differential and is arranged to open when the fluid is flowing in the desired direction and automatically close if the pressure differential falls below a desired level or if the flow of the fluid reverses. These check valves assist in preventing contamination of the upstream system if the flow of fluid reverses, or prevent the reversal of flow from a pressurized space if leakage occurs upstream from the valve.
A check valve includes a flapper member that rotates between an open position and a closed position against a valve seat. In an instance where the valve closes due to a leakage or failure of an upstream conduit or component, the flow of fluid from a pressurized space (e.g. an aircraft cabin) may result in the flapper member closing at high speeds against the valve seat. The high-speed impact of the flapper member against the valve seat may result over time in a damaged valve seat, valve hinge or housing. As a result, these valves may have to be periodically inspected and replaced or redundant valving arrangements may need to be incorporated into the system, which increases operating and maintenance costs.
Accordingly, while existing check valves are suitable for their intended purposes the need for improvement remains, particularly in the providing of a check valve with a reduced flapper closure speed and improved reliability.