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How Does a Ball Check Valve Work?

Ball check valve for wastewater systems

Check valves come with different types of on/off mechanisms. The ball check valve is one of them. To understand its operation, continue below. We have the working principle it uses illustrated, its different types explained, and a list of its typical applications.

What is a Ball Check Valve?

A ball check valve is a one-way valve that relies on a moving, spherical ball for the on/off operation. Generally, it consists of a grooved chamber, a spherical ball, a sealing seat, and the valve body.

The groove is a tapered design. For valve off, the ball moves into the narrowed end and away to open it. The tapered seat ensures a tight seal and the ball movement that media can only flow one way.

ball  valve and its parts
Inside a ball, 1-way valve

How Does a Ball Check Valve Work?

A ball check or one way valve works by moving a ball from the “valve on” to the “valve off” position based on the flow pressure. The ball floats in a cone-shaped groove or seat where it can move back and forth. Here’s what happens:

1. Valve Open, Forward Flow

  • When flow pressure is high (cracking pressure), it presses against the ball
  • Its force dislodges the ball from the seat, keeping it raised
  • Media flows through the valve

2. Valve Closed, No Reverse Flow

  • When the flow pressure is low, the ball is no longer being pressed
  • It falls back into the tapered chamber, closing the valve to prevent backflow
  • This happens under the force of backflow and gravity pull
  • In some valves, a return spring is included to force the ball into its seat
Y ball check valve and its parts
Y ball check valve and its parts

Ball Check Valve Types

Manufacturers make ball one-way valves in the following versions: floating ball type, spring loaded type, union type, flanged design, and y-shaped type. Let’s see how each differs from the other.

Floating Ball Check Valve

The floating ball check valve has the ball floating inside the tapered or cone-shaped chamber. The pressure of flow, or cracking pressure, pushes the ball away to open the valve.

Back pressure or gravity helps to push the ball back to the “valve off” position. For that reason, this valve is also called a gravity ball check valve.

Spring Ball Check Valve

A return spring operates the ball movement in some types of this valve. The spring pulls the ball into the tapered end when the flow pressure reduces, thus keeping the valve closed.

You can install the spring check valve in any direction, including horizontally, seeing that it closes automatically when the flow pressure reduces.

Union Ball Check Valve

The union check valve uses a threaded installation nut on one or both ends. The union nut(s) allows you to install and disconnect the valve for repair or replacement easily. You only need to unscrew the union and lift the valve.

A single union valve suits applications that involve pipe ends, such as those that empty water into a tank. On the other hand, the double union type fits installation in the middle of pipelines; you can unscrew it from both ends.

Flanged Ball Check Valve

The flanged type comes with a flange to connect it to a pipeline using bolts or screws. Among other benefits, this construction produces sturdy joints and easy connections.

Most valves that come with flanges are suitable for use in industrial pipelines. These include oil and gas systems, manufacturing plant pipes, and more.

Y Ball Check valve

The Y valve derives its name from its shape, which looks like a Y, with an extension from the main body. A seat inside contacts the spherical ball to seal off the orifice. Here’s how it works:

If the pressure is low, the ball rests in the seat. The valve remains closed to prevent reverse flow. When the pressure increases, the ball moves up the extension, opening the valve to forward flow.

Using a ball one-way valve in a wastewater system
Using a ball one-way valve in a wastewater system

Ball Check Valve Applications

Ball check valves ensure that any media (water, chemical, gas, etc.) does not flow back into a pipe or system. It thus finds valuable applications in homes and industries or commercial establishments. Typical uses are listed and explained below.


In a plumping system, the valve is a unidirectional valve to prevent backflow in the pipes carrying potable water. You can also use it to ensure no reserve flow occurs in your water heater or a pumping system.

Wastewater Systems

In wastewater systems, this valve prevents the reverse flow of media, helping to avoid contamination. That can happen if dirty water flows back into a clean water pipe.


The hydraulic type of this valve is suited for use in a system or equipment that uses liquid pressure to work. It prevents the backflow of hydraulic fluids, keeping them safe and operating as they should.


In the manufacturing industry, these valves ensure the success of various industrial processes by preventing backflow. Examples include plastic injection molding systems, beverage production lines, and pharmaceuticals.

In the above applications, the ball check valve provides these benefits:

  • It’s available as a vertical or horizontal type, allowing for installation in different directions or orientations
  • It’s inexpensive and suitable for many projects, including low-budget ones
  • You can use it with different media, from water to gas and air or steam
  • It has a self-cleaning ball and replaceable parts, such as seats
  • You can use it in a broad range of pressures, from low to high


The ball check valve is a versatile type of unidirectional valve. You can use it in many applications, seeing that it provides tight seals to block backflow. Different ball, one-way valves are available, too, based on the type of material, ball movement, and body design. That means a broad range of choices for your project.

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