Liquid piping applications are vulnerable to air entering the system through connections, pumps and incoming fluids, causing inefficiencies and operating issues. Air release valves are designed to combat this issue and release pockets of accumulated air to maintain a consistent and safe system. However, they must be installed at optimal locations to expel the maximum amount of air early and make the application as efficient as possible. When installed correctly and at the optimal locations, air release valves allow for greater fluid flow and help to protect systems from the chance of pressure surges.
At John Valves, we manufacture and supply air release valves in various sizes to support the efficiencies in industrial fluid applications for clients around Australia. In this article, we discuss where to install air release valves as best practices for fluid systems.
Where to install air release valves
Air release valves are installed to expel air or gases when they’ve accumulated inside liquid applications as well as assisting in the prevention of pressure surges. They’re essential in ensuring that the system is operating efficiently to maintain a high flow performance through the pipeline.
Air can enter pipelines in various ways and locations and can travel with the fluid until it becomes trapped and accumulates. It’s these areas of accumulation where valves must release air to maintain an efficient system. When possible, install the air release valves directly on top of the pipe in a vertical position to have the best effect. Below we look at various locations along the pipeline where air pockets are likely to accumulate to help you determine where to install air release valves:
Bends or elbows
Bends or elbows are typical locations for air to become trapped, as air usually has a different density to the fluid, so it can become ‘trapped’ when the flow reaches a turning point. Therefore, we recommend installing air release valves as close to bends or elbows as possible to expel air or gases from the system. When this isn’t possible, you can install a tee at these locations, which will allow the air to accumulate in the tee and then move into the air valve.
Downstream of pumps
Pumps involve multiple piping connections and pressure changes of the fluid, which can result in the presence of air in an application. Installing an air release valve downstream from pumps means that any air that enters the system at the pump can be expelled once it accumulates and reaches the air release valve. After shutdown, pump casings can also fill with air, so when the pump is restarted, this large amount of air is discharged from the pump and needs to be released before it enters check valves within the application. A specific type of air valve, called an air/vacuum valve, installed downstream of pumps is suitable for expelling this air.
High points, long runs and slope changes
As air and gases are almost always lighter than liquid, high points within fluid systems are prone to hold and trap pockets of air as it rises into these positions. Changes in pipe slope can also hold air pockets due to pressure and velocity changes. Both of these locations are suitable spots to install air release valves that expel this trapped air and enhance the system’s efficiency.
Air travelling within long horizontal pipeline runs can remain in the system for a long time without reaching a significant point to be released, making the pipeline over this length less efficient. It’s therefore a good idea to install air valves along long runs to expel pockets of air that may travel slowly and would otherwise affect the system for an extended period.
Adjacent to other valves
As an external connection point, valves are susceptible to allowing undesired air into the system. Installing air release valves adjacent to or downstream from mainline valves enables air that enters through valves to be expelled soon after it enters, minimising the inefficiencies caused.
The locations along pipelines mentioned in this article commonly contain air within applications and cause inefficiencies. While installing air release valves in these locations is recommended, it’s also important to be mindful of other areas where piping connections may allow air to enter and require an air release valve to exhaust the air. John Valves has helped many facilities operate fluid applications with sufficient, custom-made air release valves to suit their needs. If you need help in selecting an appropriate valve, please get in touch with our team.