How Do Air Vent Valves Work?

In this blog post, you’ll read:In many types of fluid control related to the flow of water supply piping air through the system and avoid hot water and air safety problems
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In many types of fluid control related to the flow of water supply, piping air through the system, and avoiding hot water and air safety problems, it’s very important to prevent air in the system. In this situation, only an air vent valve can assist you properly. Today, we will explain the functions, uses problems and solutions, buying guide, and everything necessary about brass air vent valves. So, stay till the last word.

Problems In Pipelines For Air Existence

Common problems and damages that occur when there’s a presence of air in the pipelines:

· Fluctuations in the flow and sometimes blockage up to the stoppage.

· Water hammer problem resulting in damage to the plumbing system and accessories.

· Corrosion, cavitations, and noise inside the system.

· Water is splashing in the pipe outlet and faucets.

· Improper water supply due to inaccurate meter readings and increased energy costs.

Hopefully, you now understand how much damage the presence of air can do to your pipelines. So, before these problems start, ensure your system has air vent valves for safety.

Now let’s discuss the brass air vent valves

What Is An Air Vent Valve?

The Air Vent Valve is a mechanical safety valve. It is used to release or remove the existing air from a water supply pipeline to prevent air problems. This valve is also an automatic air vent, bottle air vent, and Air Release Valve (ARV).

Air Vent Valve Components

An Air vent valve looks like a bottle from the outside. And like every bottle, it has a plug or cover. This plug covers the inner components and offers easy removal. In addition, right at the top of the cover, there’s a tiny cap thing. This cap holds the inner mechanism up. If you remove the cap and dive in, you’ll see a spring and the locking system.

After removing the plug, the inner mechanism will also come out with it. This is because the lever mechanism and the float are attached to the plug. The lever mechanism here consists of a pin and sticks to play the role of a level. Moreover, it connects to the locking system from one end and the floating from the other. Lastly, the float is a cylindrical or round-shaped thing and is very light in weight.

Above all, the rest you can see outside of the valve is the valve body. And at the bottom of the body, the threaded part works as the inlet. 

Air Vent Drawing
Air Vent Drawing

How It Vents The Air(Air release for safety and Protection)

The best thing about the air vent valve is it operates automatically without any human help. And there’s a beautiful physics working behind it. Let’s explore it.

Since the float is heavy enough for the lever, it holds it down. As a result, the valve outlet or the locking system remains open to pass the air. But when the water enters the valve, the float starts floating in the water and moves up as the water level increases. This makes the lever down on the locking side and seals the outlet. Thus, water cannot go through the outlet, but air can.

The initial air inside the pipes moves to the valve when the water starts flowing. Since the float is down and the valve outlet is open now. So, air can quickly enter and be exhaled by the valve. Further, when the water enters the valve and gradually goes up, it pushes the float up and locks the outlet. But, if some air enters the valve again, it occupies some space at the top and pushes the float down. Therefore, the outlet opens a bit and releases that air. This process repeats continuously to discharge air from the pipelines.

air vent dimensions
air vent dimensions

Where And How To Use

The brass air vent valves suit almost all irrigation or sanitary applications. You can use it anywhere where there’s a need for air removal from pipes. Examples are water distributions, water treatment plants… hot and cold water supply, pressure tanks, air conditioning, boilers, and more. 

Most importantly, remember that these valves should stay at the top position of the pipes. When water flows inside the tubes, the air will pass as bubbles. And bubbles always go upwards. So, if you install the valve somewhere below, it cannot catch and release the air.

Common Problems And Solutions

Leaking and clogging are the most common problems of air vent valves. For leakage problems, you’ll need to repair or replace them. And for clogging, an excellent cleaning can help; otherwise, replacement is the only solution.


How To Clean

Firstly, make sure to turn off the supply of that line. Secondly, grab the valve with your hand and rotate it anticlockwise to loosen and remove it. Next, remove the plug or cover with the cap to loosen all its components. Then wash all the parts. After that, reassemble the parts and install them where it was before.

Brass Air Vent
Brass Air Vent

[Note: Use check valve at the inlet to prevent dirt entries and clogging.]

How To Replace

Replacement is needed when the valve is leaking. However, sometimes a simple change can do well without any replacement. That is changing the O ring washer. 

Remove the valve from the pipeline and then disassemble the cover. You’ll see an O ring rubber washer below the body. Change this washer and reinstall the same valve. Hopefully, it’ll stop the leakage. If not, then go for the replacement. 

To replace it:

  1. Remove the valve the way we told you a while ago.
  2. Apply some Teflon tape on the threads of the new air vent valve.
  3. Install it by placing and rotating it clockwise on the threads. 

Air Vent Valve Choosing Guide

Not all types and sizes of air vent valves fit all applications. So, you’ll need to consider every small thing to select the best fit for your system. Here are the options available:

ü Body and Cover Material: Brass is best. However, stainless steel, Bronze, and cast iron are also available.

Air Vent Valves

1. Float Material: Stainless steel, polypropylene.

2. Body Finish: Sandblasted, nickel, chrome, and gold plated.

3. Thread Size: 1/2″, 1/4″, 3/8″, 1″.

4. Temperature: -10oC to 120oC.

5.Pressure: 0.1Mpa – 1Mpa.

6. End Connection: Screwed with BSP and NPT thread types.

You can pick up the ready-made brass air vent valves or customize any of these options for your application. We, Plumberstar, are always here to help you with these things. We also offer OEM and ODM. Reach us for more queries.

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