Protect Your Equipment Using Compressed Air Heater
When the topic of discussion is about compressed air and air compressors, people always talk about cooling. It’s because air compression generates heat, so yes, compressor needs to be cooled. Compressed air is always hot… so why do you need a compressed air heater?
This is actually because you need to prevent condensation of water vapour that can affect your sensitive equipment.
Let us first talk about compressed air, dew point, and relative humidity.
The air coming from your compressor is usually about 30 degrees Celsius and saturated with water with100 relative humidity. This is if you do have an aftercooler. Having 100% relative humidity means once the temperature drops, there will be more water drops (condensate) forming.
Having an air dyer helps a lot as compressed air dryers can remove a lot of water vapour from the air. The usual type of compressed air dryer can dry the air up to a pressure dewpoint of 4 degrees Celsius. F
What that means is that as long as the temperature doesn’t go below 4 degrees Celsius, there will be no condensate forming. Most applications will find this suitable. The only thing you have to worry about is if you have compressed air piping outside of the building, you can get some problems with water condensate during winter.
Compressed Air Expansion
We all use compressed air for a purpose. It could drive a pneumatic actuator, actuate valves or perform other tasks. In all its uses, compressed air is expanded again to ambient pressure. When air expands, it cools down. It’s the opposite of compression which heats up the air. When a lot of air is expanded in a certain part of your equipment, it can get really cold. How cold? Freezing cold!
This can result to valve icing. It can be a big problem in industrial applications as the valve can get stuck in either open or closed position when the condensate water does freeze up inside the valve. Small valves and other openings can completely freeze shut when there’s too much ice deposit inside.
Lower the Dewpoint
You can use a desiccant compressed air dryer to get the air to a dewpoint as low as -50 degrees Celsius but a desiccant dryer can be expensive! Also while that can solve the problem of condensate forming inside the valve, it can still get very cold, which is a problem for precision devices.
Compressed Air Heaters
Another good solution is for you to use a compressed air heater to pre-heat the compressed air before it is expanded. Since you start the expansion with hot air, the end temperature will be above freezing point.
A compressed air heater is a heating coil inside a housing that is sometimes combined with a compressed air filter to serve as an all-in-one solution. You can usually set the desired temperature, but sometimes it’s a fixed value.
When buying a compressed air heater, make certain that you get one with enough power. Also, ensure that it can reach the temperature that you need.