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How Does a Brass Check Valve Work

Brass check valve opening and closing diagram

A check valve only allows media to flow in one specified direction. The brass check valve is one such valve. Owing to the many benefits of brass, check valves made from it are popular in many applications, from home plumbing to industrial systems. Below, we look at how the brass, non-return check valve works and its different types.

A brass check valve uses inlet fluid pressure to open. It then uses backpressure or mechanical components, such as a return spring, to close. In other words, it only allows media to go in one direction and not the other and is also called a one-way valve.

To better understand the working principle of check valves, here’s what you need to know about their operating pressures. These are the opening pressure, also called cracking pressure, and the closing action when the force is not acting.

Check Valve Cracking Pressure

A check valve opens when the pressure of the media upstream reaches a specified level called cracking pressure. When that happens, the valve opens, letting water, gas, or other medium through.

The valve remains open as long as the cracking or inlet pressure is high. Note that check valve cracking pressure levels are different for different device designs.

Closing Pressure

The closing pressure is the pressure level that falls below what the valve requires to remain open. The check valve closes once the inlet or upstream pressure reaches this level.

The closing action of a check valve can also result from back pressure or the force of the reverse flow. Additionally, the valve can close under the action of gravitational force or with the help of a spring and any other mechanism.

Inside a brass spring check valve
Inside a brass spring check valve
Resource: https://www.youtube.com/watch?MeDflQ1IHM0

Brass Check Valve Types

Different types of check valves use varying mechanisms to allow and restrict media. To shed more light on that, we explained the working of popular kinds of this valve. They are swing, spring, ball, lift, and the foot brass type—a check valve with a filter.

Brass Swing Check Valve

As the name suggests, this check valve type uses a swinging hinge for the opening and closing action. The disc, held by a hinge, can move up and down. Here is how a brass swing check valve works:

  • When the inlet pressure is high, the media pushes the hinged disc up
  • This opens the valve
  • When the media ceases to flow, the valve falls under its weight
  • This action results in the valve closing.
  • The weight of the disc must be high enough for gravity to move it
  • The disc may also use a spring mechanism to pull it down or depend on backflow to close

Brass Spring Check Valve

A brass spring check valve uses the action of a spring to return to pull a disc to its original position and prevent backflow. These valve types come in a variety of configurations. However, their general working principle is as follows:

  • When the inlet reaches cracking pressure, it overcomes the pull of the spring
  • The valve opens, allowing flow
  • When the flow ceases, the pressure drops and the spring pulls at the disc
  • This causes the valve to open, usually with the assistance of backpressure to prevent reverse flow

Brass Ball Check Valve

A brass ball check valve relies on the action of a ball to open and close. The ball moves up and down inside the valve and can be a floating or spring-loaded type. Here’s what happens:

  • When the inlet pressure is below the specified cracking pressure, the ball rests on a conical seat
  • The ball’s position creates a tight seal, preventing any backflow
  • As soon as the pressure increases to a cracking level, the ball pushes away and opens the valve
  • The reverse happens if there’s low pressure or reverse flow

Brass Lift Check Valve

The brass lift check valve is called so for using a raise and drop mechanism to operate. This is usually a disc that, under the inlet pressure, can vertically rise and fall when the flow ceases.

  • If the upstream pressure is high enough, the disc will rise in its guiding mechanism
  • Upon sensing a decrease in pressure, the disc will fall under gravity
  • This causes it to align with the valve seat and shut it
  • Some types of this valve feature a return spring.
  • If not, the valve is mounted in a way that allows gravity to act on the disc

Brass Strainer Check Valve

Also called a foot check valve, this type comes with a screen or filter. The screen, which sits on the inlet side of a suction pump, helps keep debris away while preventing backflow. Let’s see how it works:

  • During operation, water is freely rushing through the valve and suction pipe
  • When the flow stops, the valve quickly closes
  • The weight of the water as it rushes down under gravity is what causes the valve to close
  • A brass strainer check valve is typically used in applications where clogging can be a problem
  • These include fuel tanks and other applications such as the suction ends of well pumps.
Double check valve
Double check valve
Resource: https://www.youtube.com/watch?v=o66WY3ifloA

Dual Check Valve vs. Double Check Valve

In addition to the mentioned types, a brass one-way check valve can be a dual or double configuration. These feature two valves connected in series. They help stop backflow that may result in contamination or hazardous situations.

One valve is a backup to the other in the event of failure, making them essential parts of many systems today—more about the difference between the dual and double valves below.

Brass Dual Check Valve

The dual type uses two check valves combined in series. These close under the action of a return spring. Dual check valves do not include isolation or shut-off valves.

They also often do not come with test valves. It’s, therefore, recommended only to use these valves in residential settings.

Brass Double Check Valve

A double backflow preventer valve combines two single valves. However, unlike the dual type, it comes equipped with isolation valves and, most often, some test valves.

Typical applications that suit a brass double check valve include the backflow prevention systems of swimming pools and irrigation equipment.

Brass, swing check valve installation
Brass, swing check valve installation
Resource: https://www.youtube.com/watch?dvjemyIKl4I

Brass Check Valve Uses

Brass offers various advantages when used to make valves. A brass one-way check valve is durable, inexpensive, and resistant to corrosive materials. You can also use brass backflow preventers with various media types, including air or gas, fuel, and water.

Pumping Systems

A brass water check valve finds essential applications in the plumbing systems of homes, commercial facilities, or industrial plants. In these applications, you can use them as shut-off or control valves.

As we saw earlier, check valves made of brass are popular in the pumping systems of wells. Here, they help prevent water from flowing back while also blocking debris.

Automotive

In the automotive world, brass check valves are installed in older motor vehicles to prevent reverse flow. You can also use a brass fuel check valve with other fuels, such as jet fuel.

Backflow preventer valves made of brass are also available in various design options. That includes designs that fit both vehicle and aircraft applications.

Pneumatic Equipment and Systems

Brass air check valves find application in compressors and other pneumatic equipment and systems. They help prevent the backflow of fluid while letting it through whenever needed.

In low gas pressure applications, you can use them as a pressure relief valve that comes into operation when the pressure exceeds a preset level.

There are many other uses of brass valves that work by preventing a reverse flow. The above mentioned examples are only some of the most common.

Conclusion

The brass check valve is a versatile type of valve in various situations. From water to air and fuel or gas, it helps prevent reverse flow while offering the advantages of brass as a material for fittings. The valve also comes in various designs and operating mechanisms. That, in turn, means an array of options to fit your project or other use.

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