A GUIDE TO DRYERS
Of course, air treatment is not just good for your bottom line, it is often also mandatory. Many industries and applications have specific air quality requirements that you must be aware of.
The best way to do so is by using ISO 8573-1, the most important internationally recognized air quality standard. It tells you how many contaminants (in this case moisture) your air is still allowed to contain at a specific point in your compressed air system after it has been treated.To identify your drying needs, you should consult the chart below and pay close attention to the “Water” column. As you can see, there are seven different classes (with 0 being the most stringent).
0.1 < d* ≤ 0,5 µm
0.5 < d* ≤ 1,0 µm
1.0 < d* ≤ 5,0 µm
≤ 20.000
≤ 400
≤ 10
≤ -70
≤ -94
≤ 0,01
≤ 400.000
≤ 6.000
≤ 100
≤ -40
≤ 0,1
≤ 90.000
≤ 1.000
≤ -20
≤ -4
≤ 1
≤ 10.000
≤ 3
≤ 37,4
≤ 5
≤ 100.000
≤ 7
≤ 44,6
≤ 5mg/m³
≤ 50
*d = particle diameter
While the other contaminants have a certain threshold of particles or oil per cubic meter, the water in your compressed air is measured by its pressure dew point (PDP).What is that?The PDP is used to define the water content in compressed air. Essentially, it is the temperature at which water vapor condenses into water at the current working pressure. Low PDP values indicate small amounts of water vapor in the compressed air.
To make that happen, you need the right dryers … and to choose the optimal technology for your application, you first have to figure out your dew point requirements.
Here is a helpful rule of thumb: If the pressure dew point is below 3°C (37.4°F), then it is likely that the right solution is a desiccant adsorption dryer, which can achieve a PDP of -40°C or lower. That makes them suitable for providing very dry air for critical applications. If your dew point requirements are less stringent, then you can probably work with refrigerant dryers.Let’s take a closer look at these different technologies.