How do Air Release Valves Work?

Automatic air release valves are a valuable part of any piping system. These valves have a few different applications and offer a variety of benefits.

air release valves

What are Air Release Valves

Air release valves are a device that is installed on a piping system that continually release any excess air out of the piping system. Any trapped air in a piping system can cause inefficiencies and be dangerous.

They are often used in water applications and ensure that no air is trapped within the system. Any air pockets can cause pressure build-up within the system. Releasing air pockets improves efficiency by reducing the change of flow reduction, reducing head loss, and reducing energy consumption.

The Importance of Air Release Valves

Any air left in a piping system can cause a variety of problems. From head loss to high pressure water surges known as water hammers. Any surge in pressure can cause damage to the pumps, pipes and valves. Pockets of air can even cause flow stoppage if left for too long.

Where does the air come from?

There are 3 main ways that air becomes trapped in a pipeline. The first is from the pipeline itself. Although it may seem that a new pipeline is empty, it is filled with air. This air must be evacuated as the pipeline is filled with a liquid.

The fluid itself can also cause air buildup in the pipe. Did you know that even water contains 2% air by volume? Other liquids can also contain air by volume, especially thicker fluids and adhesives. As they move along the pipeline, the air can separate from the fluid and accumulate in the pipe.

Mechanical equipment can also draw air into the system. Common areas for this to occur include valves, pipe joints, pumps and packing.

How do Air Release Valves Work?

Air release valves are designed to automatically remove (release) the air from the pipe. They are strategically installed in the parts of the pipeline that naturally collect air.

The valves have small orifices with weighted floats and mechanisms that all work together. In order to work, the valves are left open to release the air, as fluid enters the valve, the float rises to the top and seals the valve. As the air rises, the float will drop and allow the vent to open, releasing any excess air in the pipe.

Applications for Air Release Valves

The main application for air release valves is in sewer mains and water pipelines. The best application for these valves is for pipelines that have small volumes of air that need released.

Air release valves protect the system and reduce damages to the mechanisms within it. They are designed to remove air quickly as a pipe is being filled, but also to let air in when the pipeline is empty to maintain a constant pressure within the pipe.

Correctly installing a valve ensures that it operates as expected and operates automatically.