Pressure Control Valve: All About The Check Valve

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How does a check valve work?

A check valve is a type of pressure control valve that allows only a single direction for the flow of fluids. There are only two ports: an inlet port and an output port. Since the media is only allowed to flow in one direction, check valves’ main purpose is to prevent backflow in the system.

One, two, three, four, Pressure!

A check valve heavily relies on pressure to work (hence called, pressure control valve). Naturally, higher pressure on the input side of the valve is needed than on the output side to open the valve. When the pressure shifts to the output side, the valve automatically closes. Unlike other valves, they don’t need manual handles, levers, or actuators to work correctly.

Importance of check valve application

Check valves are usually used in applications wherein backflow might cause an issue. Since they are “non-return” valves, they are an easy, effective, and cheap solution to solve an obvious potential problem. Backflow can cause a lot of damage if it is contaminated, thus, contaminating the media upstream. For instance, a check valve ensures that waste from a sewer line can leave, but not re-enter the system. They are also used to ensure that backflow will not damage equipment upstream.

The check valves’ cracking pressure

A check valve requires a minimum upstream differential pressure between inlet and outlet to open the valve and allow through flow. This required minimum upstream pressure is called the check valve ‘cracking pressure.’ Specifics of the cracking pressure may change based on the valve design and size.

Check valve closing action

If the upstream pressure falls below the cracking pressure, or there is a danger of backpressure/backflow, the check valve automatically closes. The closing mechanism will depend on the valve’s design, such as a gate, ball, diaphragm, or disc against the orifice. Since the main purpose of the closing action is to seal completely, it can be assisted by gravity or a spring.

Get quality valves from MasterMac 2000 P/L

When Univer first came out in 1980, its original valves, sub-bases, spool systems, and cylinders have proven to be of the highest quality in the international and Australian markets. They can be used for all industrial applications, including heavy applications. For quality pressure control valve and check valve systems, get in touch with MasterMac2000 today on 07 3344 4711 or visit

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