Compressed Air Dryers are very important in the compressed air system, because it removes moisture from the air and prevent corrosion. Without it many automated pneumatic system will breakdown from mechanical failure. There are 3 types of dryers in
• Refrigeration Dryers +3 ˚C to + 5 ˚C
• Desiccant Dryers -40 ˚C to -70 ˚C
• Membrane Dryers -5 ˚C to -10 ˚C
The selection of the type of dryer is dependent on the application and the process. As a guide line the international standard ISO 8573.1 is used.
For semiconductor sector, Class 1 & 2 is preferred because of its low moisture, oil and dust content, while medical sectors uses Class 2 & 3, General Industry uses Class 4, 5 & 6. But in food industries especially for packaging, sometimes Class 2 is required to prevent food contamination.
Desiccant dryer is used when a low dew point is required.
The desiccant dryers are categorized into 2 types and is mainly the way the desiccant is regenerated. But VAPS Technologies together with our manufacturers Newgate Technologies, Inc from USA is offering a third option which will offer customers an even higher energy savings compared to both standard pressure swing and heat regenerative dryers. The new 3 main categories are as follows
• Vacuum Assist Pressure Swing (VAPS) Dryers (ENERGY SAVING)
• Pressure Swing Dryers
• Heat Regenerative Dryers
As an operating standard for desiccant dryer, the wet air is flowed through a desiccant bed which can consist of either Silica Gel, Activated Alumina, Molecular Sieves or a combination of the latter 2 types. The desiccant has very fine capillary on its surface which makes it very Hygroscopic and will adsorb the water molecules from the compressed air. In the process of adsorbing it releases some energy in the form of heat which we call it Heat of Adsorption.
In the pressure swing dryer the heat of adsorption is needed later to be reabsorbed back into the desiccant to release the water molecules during regeneration, therefore the cycle time for pressure swing dryers are usually short.
For heat regeneration systems, since we are introducing heat into the system to regenerate the desiccant, we do not need to maintain the heat of adsorption in the vessel, thus the cycle time here is long.
Please call us for your requirements
|Why Do We Need Condensate Drains?
Condensate is generated from water vapour in the air after compression. Water vapour that is present in the atmospheric air is not saturated and is usually denominated by a percentage of saturation. A common name used here is Humidity. When a compressor takes in the air from the surrounding & compresses it to a higher pressure, the amount of water vapour present in the air will increase accordingly when the volume reduces. This will push the humidity level above 100% and thus condensation starts
to happen. The amount of condensation will depend on the pressure and temperature of the compressed air. Most often after compression the air is very hot and thus no condensation will happen. Condensation will only happen when the air is cooled down in the after cooler and in the refrigeration dryer. When the compressed air is cooled down, it is pushed into the saturated zone and condensation happens.
Why we must remove condensate
Condensate contains large amount of water, oil and particles and thus will cause damages to the machine. Water will cause piping to rust and scales to form and this will cause wear and tear to the pneumatic components. Compressor Oil on the other hand is not suitable as a lubricant for the pneumatic components and thus will cause it to hesitate or damaged.
Often compressed air users uses an open orifice to remove the condensate from the system but we have to know this method is a very expensive method. Air compressors uses large amount of energy to generated compressed air and thus compressed air has a value to it. As a rule of thumb the cost of compressed air is about :
Oil Lubricated: RM0.03(USD0.008) per m3
Oil Free : RM0.04(USD0.010) per m3
If there is a small leak, money is constantly lost. The below table shows the amount of air loss for various pressure and open orifice
Air loss per Cubic Meter per hour
As an example from the above,
- Pressure : 6.9 bar
- Orifice Size : 3.2mm
- Working Hrs per Year : 8000hrs
- Cost of Compressed Air : RM0.04
Total Money Lost Per Year = RM14,080.00 (USD3705.00)
So we need to ensure that the leaks from condensate outlets are plug
Condensate Drains Available
There are many types of condensate drains available and the main ones are as follows
- Float Drains
- Timer Drains
- Zero Loss Pneumatically Operated Drains
- Electronic Zero Loss Drains
VAPS Technologies offers all of the above autodrains but specialize on the Pneumatically operated Zero Loss Drains.