Air Blast Oil Cooler
Functions of compressed air after coolers : –
- Cool air discharged from air compressors via the heat exchanger
- Reduce risk of fire (Hot compressed air pipes can be a source of ignition)
- Reduce compressed air moisture level
- Increase system capacity
- Protect downstream equipment from excessive heat
Coolers are usually sized with a CTD (Cold Temperature Difference) of 5°F, 10°F, 15°F or 20°F (2.7°C, 5.5°C, 8.3°C, or 11°C). This means that the compressed air temperature at the outlet of the aftercooler will be equal to the cooling medium temperature plus the CTD when sized at the specified inlet air temperature and flow.
Recommended location of after coolers : –
The aftercooler should be located as close as possible to the discharge of the compressor.
Types of after coolers
There are two basic types of air aftercoolers:
- air-cooled
- water-cooled.
The type of aftercooler you choose depends on your preference and requirements.
Compressor manufacturers may include aftercoolers within the compressor package. In general these compressors are referred to as integral aftercoolers. A stand-alone or freestanding aftercooler is a separate unit installed downstream of the compressor.
Maintenance requirements : –
Aftercooler (water-cooled): Routinely inspect, clean, check approach temperature, pressure drop and monitor water quality.
Aftercooler (air-cooled): Inspect and clean on a regular basis. Check drain valves daily.
Proper maintenance will keep the aftercooler efficient. A dirty aftercooler results in both warmer air temperatures and increased pressure drop.
Rules of Thumb : –
- Most aftercoolers are sized to cool the air to an approach temperature of 5 to 20°F (2.7°C to 11°C) of ambient air temperature.
- Size for the hottest day with 100% relative humidity.
- Compressed air aftercoolers are located directly downstream of the compressor.
- Proper maintenance will keep the aftercooler efficient. A dirty aftercooler results in both warmer air temperatures and increased pressure drop.
- For every 20°F (11.1°C) rise in compressed air temperature, the moisture content of the air doubles.