What Is a Check Valve and How Does It Work?

Check valves have several other names, such as one-way, non-return, or clack valves. They have a design that is used for the guarantee of unidirectional flow. With this, they are often used as a preventive measure to avoid overflow, backflow, and other hazardous operating conditions. As such, they are found in a wide variety of fluid handling systems. A few check valve applications are irrigation systems, oil and gas extraction and processing equipment, potable water systems, standard and critical power generation and distribution equipment, subsea operation systems, wastewater treatment facilities, and more.

Check valves are available in various designs in the market and they usually vary with respect to the shape and structure of the element. However, every check valve has the same basic principle of operation. To ensure that you only procure the best fit for your operations, we will discuss check valves in more detail and provide an overview of the most common options.

How Do Check Valves Work?

Check valves have a unique design of the two-port system. These two ports are separated by a regulating mechanism known as a clapper. In the first port, the fluid enters through its opening. Then it flows from the first port to the second port, and the clapper aids in preventing the valve from flowing in the backward direction. This type of valve design makes operation much easier without involving any humans because it all depends on the pressure of the fluid to open or close the valve. As a result, most check valves usually require minimum upstream pressure.

Axial Flow Check Valves

Axial flow check valves are often known as nozzle check valves. They generally feature a spring-loaded disc and remain closed when the cracking pressure is low, but they open completely and immediately when the pressure is surpassed. These check valves are suitable for maintaining continuous flow at minimum pressure and eliminate water hammer effects. 

Ball Check Valves

The ball check valve features a spherical clapper that may or may not be spring-loaded, all depending on the application. Also, they should be placed in such an area that is easily accessible for everyday maintenance and repair.

Diaphragm Check Valves

Diaphragm check valves have a rubber diaphragm clapper that opens when the upstream pressure is higher than the downstream pressure. They usually close when the pressures are equal or when below the set standards.

Duckbill Check Valves

As the name suggests, duckbill check valves have elements shaped like a duck bill and they are used to control flow. Their opening action is caused by upstream flow, and their closing action is affected by the downstream flow. 

Stop Check Valves

A stop check valve is generally used by industry experts to stop valve operation whenever required, regardless of flow. They also use an external control mechanism, such as an actuator, handwheel, or lever.

Swing Check Valves

Swing check valves are often known as tilting-disc check valves. They usually consist of a hinged clapper that swings open toward the outlet port.


If you require check valves or any other aviation parts, then Sourcing Streamlined is your go-to solution for such devices. We are a premium distributor of aviation, NSN, and electronic components. At Sourcing Streamlined, customer satisfaction is always our priority. We have a two billion-plus item inventory stocked with offerings of the highest caliber. If you require any aviation parts, we invite you to take advantage of our Instant RFQ services. With 24/7x365 availability, all requests will be returned to you within 15 minutes or less upon submission of a completed form. 


November 2, 2022

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