Air Release Valve Overview

An air release valve, also known as an air vent valve or air relief valve, is a crucial component installed in underground water or wastewater pipelines. Its primary function is to automatically release air pockets or trapped gases from the system. By doing so, it helps maintain optimal system performance and prevents potential damage that can occur due to the presence of air in the pipelines.

Here are some key points about air release valves:

1. Function: The main purpose of an air release valve is to release air or gas that may accumulate in water or wastewater pipelines during system operation or maintenance activities. Air pockets or trapped gases can cause numerous issues, such as reduced flow capacity, increased pressure, water hammer effects, and pipe corrosion. The air release valve effectively eliminates these problems.
2. Operation: Air release valves operate on a simple principle. They are designed with a float mechanism or a combination of a float and a lever system. The valve is typically closed when there is no air present in the pipeline. As air accumulates in the system, it rises to the top of the valve, causing the float to rise. Once the float reaches a certain level, it opens the valve, allowing the trapped air to escape. When the air is released, the float drops, and the valve closes again.
3. Types of Air Release Valves: a. Automatic Air Release Valve: This type of valve operates automatically, relying on the float mechanism to open and close the valve as required. It is the most common type used in water and wastewater systems. b. Combination Air Valve: A combination air valve serves multiple functions, including air release, air vacuum, and large air volume relief. It combines the features of an air release valve and an air vacuum valve into a single unit.
4. Location and Installation: Air release valves are typically installed at high points in the pipeline or at specific locations where air pockets are likely to form. These valves are usually found at high elevations, near pumps, on the crest of pipelines, or at the top of slopes. Placing them strategically ensures efficient air release and prevents air accumulation in the system.
5. Importance: a. Preventing Damage: Air pockets can cause significant damage to pipelines and associated equipment. They can lead to reduced flow capacity, increased energy consumption, and even pipeline bursts. Air release valves help prevent these issues by eliminating trapped air or gas. b. Maintaining System Performance: Properly functioning air release valves ensure optimal system performance by reducing pressure fluctuations, preventing water hammer effects, and maintaining a continuous and uninterrupted flow of water or wastewater. c. Minimizing Corrosion: Air trapped in pipelines can accelerate corrosion, especially in metallic pipes. By releasing the air, air release valves help minimize the potential for corrosion, thereby extending the lifespan of the pipeline.
6. Maintenance: Air release valves require regular inspection and maintenance to ensure their proper operation. This includes checking for any blockages, cleaning or replacing damaged parts, and verifying the float mechanism’s functionality.

In summary, air release valves play a crucial role in water and wastewater systems by automatically releasing trapped air or gas. They contribute to optimal system performance, prevent damage caused by air pockets, and help maintain the integrity and efficiency of underground pipelines.