Air valves are a crucial component in pipeline systems, so it is not a matter of whether or not they are needed, it is a matter of why. There is a wide variety of different air valves, each of which serves a particular purpose in its system, and each of which is equally as important as the others.
Essentially, air valves do something to control the flow of air in a pipeline, and the valve chosen is directly related to the air flow requirements of the system.
1. Air release valves
In pressurized pipelines, air can become trapped which can throw off the pressure of the flow in the pipe and cause various other issues like corrosion, pressure surges, and increased stress on pumps and other parts of the pipeline. Air release valves release the trapped air.
Most of the air will exit out the other end of pipes or faucets, but since air naturally rises, it often becomes trapped in high points of the system. Air release valves are installed in those high points so that it can let it go. The air builds up to a certain point, and then when the pressure is too much, it is released through the valve.
Once it is released, the valve closes again and the process begins over.
2. Vacuum valves
Vacuum valves are used to both release and take in air in a pipeline. When doing so, vacuum valves are known for either taking in or releasing very large amounts of air at a time, and thus also go by the name “large orifice valves.”
These valves are used in pipelines to help avoid collapse or other damage, as well as to maintain proper pressure in the system. Vacuum valves are mostly used for industrial purposes in pumps for plants, factories and other large facilities.
3. Combination air valves
Combination air valves, as the name indicates, combine both air release valves and vacuum valves. They release air that builds up, as air release valves do, but they also release or bring in large volumes of air like vacuum valves.
Combination air valves can be made in either single or dual body formats. The single body formats are cheaper and smaller, but the two parts of dual body combination valves work independently of one another which is a huge benefit.
4. Butterfly gas/air valves
Butterfly valves are so called due to the identifying butterfly plate that is used to release or block the flow of a pipe. They are primarily used when the flow of a pipe needs to be easily transferred from open to closed quickly.
A disc is placed in the middle of the pipe and is left sideways when the valve is open. When it needs to be closed, the plate is turn to block the flow of the pipe. These valves are excellent when the volume of gas needs to be highly controlled. Butterfly valves are light-weight, small, and are simple in their construction. They are also very easy to operate, however they do not tend to seal very well.
5. Check valves
Check valves, also known as reflux valves, retention valves, or one-way valves, among other names, allow the flow of air in only one direction. They are used to avoid backflow in a system, and to regulate the pressure.
Check valves can be used for both industrial and domestic purposes. For instance, air compressors use check valves. Industrially they are used to avoid the cross-contamination of gases that are to be mixed. Since check valves eliminate backflow, there is no worry about gases or other substances being pulled backwards through the pipe.