Check Valves

Curtiss-Wright Valves Division offers a large range of high-quality check valves from their product brands Phönix, Valve Group-Korea, and Strack. Check valves are self-automated one-way valves, designed to allow the flow of gases and liquids in only one direction, automatically preventing any reverse or backflow.

A check valve comes in many different forms and offers various solutions for multiple applications. As a check valve is so versatile, it can be found in almost every industry that uses pumps. The collection of check valves we supply include:

  • Angle control valves
  • Swing check valves
  • Piston check valves
  • Micro control valves
  • Cryogenic service valves
  • An array of control valve variations, such as single, double, multi-stage, cage-type, and more.

As each of the check valves in our diverse range is of the highest quality, with leak-free sealing and long-standing durability, all are guaranteed to help keep your equipment running smoothly.


CHeck valves: purpose & functionality 

Check valves are self-automated valves that allow the flow of gases and liquids to move one-way, preventing any reverse or backward flow of material inside a pipeline. Its versatile nature allows them to be installed vertically or horizontally, without human interaction, and reliant on the flow to open and close. The internal disc inside the check valve allows the flow to pass forward, which opens the valve. Dependent on its design, the disc starts to close the valve as the forwarding flow decreases or reverses.


  • Available in a wide range of sizes
  • Reliable
  • Prevents backflow
  • Lower maintenance costs
  • Increase energy savings
  • Cost-effective
  • Maintains pressure
  • Serves as a backup system
  • Can be used horizontally and vertically
  • Flexible when dealing with a variable flow
  • Reduce the chance of sudden valve failure, as they eliminate chatter vibration


Check valves are primarily used for one of four reasons in a wide variety of applications:

  • To prevent siphoning
  • To keep a valve sealed
  • To prevent reverse flow causing contamination
  • To prevent reverse flow causing equipment damage

The nature of their functionality proves useful in household appliances such as dishwashers, wastewater lines, and washing machines, including more industrial purposes like boilers, pumping applications, gas systems, furnaces, and CO2 lines in aquariums. However, they are most commonly used in water and air applications. 

Pneumatic Check Valve

Pneumatic check valves are automated and do not require any manual operation to open or close. Often known as one-way air valves or air check valves, they allow airflow in and prevent it from coming out. They have a specified cracking pressure, which is the minimum pressure required to enable the valve to operate. 

Check Valves for Water

Numerous water applications are home to check valves, such as drinking water and wastewater. Check valves in drinking water applications ensure that no media from the outlet side of the valve can enter the system with clean drinking water and contaminate it. The same goes for wastewater applications; they ensure that the contaminated water cannot re-enter the system and cause an overflow. 

types of check valves

A check valve is the simplest type of directional control valve used in hydraulic systems. There are numerous types of check valves, all with defining characteristics that work more effectively with different applications. 


Usually compact and cost-effective, ball check valves have a spherical moving part to block flow within a pipeline. It’s sometimes spring-loaded to help keep it shut, or otherwise, the reverse flow is required to move the ball toward the seat and create a seal.  


Mounted with a disc that swings on a hinge or shaft, the disc swings off the seat to allow forward flow; when the flow stops, the disc swings back to the seat to block flow moving in reverse. Swing check valves need to be cleaned, so they aren't entirely maintenance-free, so it's crucial to install them in a convenient place that can be inspected.  

Related products: S72 - Swing Check Valve


A disc features inside a piston/lift check valve that lifts up off its seat by higher pressure of the upstream fluid to flow to the outlet or downstream side. When the pressure drops, gravity or higher downstream pressure causes the disc to lower onto its seat, shutting the valve to stop reverse flow.

Related products: S27 - Piston Check Valve


Stop-check valves are used as a check valve or isolation valve. They can responsively stop flow irrespective of the flow direction or pressure in the pipeline, including being shit by an external component.


A dual plate check valve is known by many names, such as a butterfly check valve, folding disc check valves, or double-disc. It features two halves of the disk move towards the center of the pipeline with the forward flow, and it closes with the reverse flow by two halves open and resting on the seat to close the flow. Lightweight and compact in its construction, it’s a low-cost installation and maintenance choice. 


The tilting design feature allows the valve to open fully and remain steady at lower flow rates, ensuring it can close quickly when the forwarding flow stops. The disc has a bevelled seat on the body and the disc edge, allowing tight shut-off at any pressure.


Wafer check valves are a compact and low-cost solution and are the preferred type of check valve for most applications. The valve opens and closes at extremely low-pressure moments over the valve disc. 


Angle control valves are often used in piping systems where space is required, such as drain services, boiler feedwater, and other piping services. The valve's body features a right angle, which prompts the directional change of the flow. 

Related products: 7000ACV - Angle Control Valve (zen-trol type), 7900SATV - Sweep Angle Trim Valve 


A micro control valve is a microscale valve, often less than 10mm, which features two ports to regulate flow. They are usually found in fluidics and microfluidics to control fluids or gases, and the valve is electrically controlled. Micro control valves are often used in the inlets and outlets of micropumps, where the liquid or gas is needed to flow in one direction. 

Related products: 23XXMCV - Micro Control Valve


Cryogenic service valves are suitable for use in very cold applications, ranging from -40 C to -196 C, and feature a long neck bonnet. They can help store and transport tons of cryogenic gasses such as Compressed Natural Gas or Liquefied Natural Gas; when heated, these gases can expand hundreds of times, becoming flammable and explosive.

Related products: 22XXCSV - Cryogenic Service Valve


A control valve is used to control the flow rate of fluids or gases using a controller. Allowing direct control of flow, pressure, liquid level, and temperature within the passage. 

Related products: 2000GCV - General Control Valve, 4000SCV - Standard Control Valve, 4000ZCV - Zen-trol Control Valve, 4X1XSTD - STD Control Valve (cage-type), 4X2XCV - Control Valve (single-stage), 4X3XCV - Control Valve (double-stage), 4X4XCV - Control Valve (double-stage w/difusser), 4X5XCV - Control Valve (multi-stage), 4X6XCV - Control Valve (Zen-trol type), 4XXXCV - Control Valve (steam conditioning), 8000CVSB - Control Valve (split body), 8500CVD - Control Valve (diaphragm weir & pinch)

How do check valves work?

Check valves rely on a pressure differential to work effectively. With two ports, an inlet for the media and output to release it, a check valve controls the flow of fluids in one direction. It does so by measuring the pressure, and if it is higher on the outlet side, the valve will close. If the pressure is not high enough on the input opening, it will close. As there are so many types of check valves, each closing mechanism will differ. 

Can check valves fail?

Check valves can fail, and they start to emit warning symptoms when something isn't quite right. Look out for reverse flow and excessive component damage. Some valves may even begin to vibrate, make noise as they start to break down, and lose internal parts when problems arise. If you're able to recognize the early signs of valve failure, you'll be able to prevent the valve from falling and avoid costly repair or downtime. 

How long do check valves last?

It's recommended check valves are tested every 12 months to check for signs of wear and tear. Although dependent on the application and frequency of use, most check valves will need repairing or replacing after 3-5 years.