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Air Dryers |
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| The air dryers available today can be segregated into two major |
- Refrigerated
- Heatless
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| Before discussion about dryers, it is very essential to define Dew point temperature,which is the unit of measurement for dryness of compressed air. |
| DEW POINT temperature is the temperature at which the moisture, which is in the compressed air (in vapour form). condenses to liquid form. |
| PRESSURE DEW POINT termperature is the dew point temperature of the compressed air,when under pressure. |
| ATMOSPHERIC DEW POINT temperature is the dew point temperature of the air when it is at atmospheric pressure. |
| The conversion chart from pressure depoint temperature to atmospheric dew point temperature is provided at the end of this text. |
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| Refrigerated air dryers are the most advanced and cheapest mode of drying compressed air. This dryer operates on the principle that cooling of the compressed air. causes condensation of water carried by the compressed air in vapour form. In the refrigerated type of air dryer the cooling takes place in two stages. The compressed air at about 40 Degree C, which enters the Refrigerated type air dryer, first enters the Precoofer . In the precooler the incoming hot-wet air is cooled by the outgoing cool-dry air. In the bargain the outgoing cool-dry is heated upto operating temperature of about 28 � 32 degree C.The hot-wet air, now partially cooled. enters the evaporator. In the evaporator, this partially cool air is chilled down to a temperature of about 2 to 8 degree C. Due to this chilling, the moisture carried by air in vapour form is condensed. This chilled air, carrying condensed moisture, then travels into the moisture separator. The moisture separator is a mechanical equipment, in which the condensed moisture is separated from the air by mechanical action. This moisture is drained out from the moisture separator with the help of an automatic drain valve. This dry-cool air is then passes through the precooler as discussed before. By this process you get dry air at the outlet with a pressure dew point temperature of about 4 Degree C or as required. (but above 2 degree C). In case of refrigerated air dryers, the power consumption for air dry- ing is approximately 5.0 kwh for 1000 cubic feet per minute of air. |
| Refrigerated Air Drier |
Heatless Air Drier |
| Dew Point Atmospheric : - 23 degree C |
Dew Point Atmospheric : - 40 Degree C |
| Moisture Content in comp.Air : 700 ppm |
Moisture Content in comp. Air : 80 ppm |
| Purge Air loss : Nil |
Purge Air loss : 15 % of compressed Air |
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| Model |
Capacity (CFM) |
| RFG - 20 |
20 |
| RFG - 40 |
40 |
| RFG - 60 |
60 |
| RFG - 80 |
80 |
| RFG - 100 |
100 |
| RFG - 150 |
150 |
| RFG - 200 |
200 |
| RFG - 250 |
250 |
| RFG - 300 |
300 |
| RFG - 400 |
400 |
| RFG - 500 |
500 |
| RFG - 600 |
600 |
| RFG - 750 |
750 |
| RFG - 1000 |
1000 |
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- Inlet Air Temperature 40 Degree C
- Pressure Dew Point : 2 Degree C to 5 Degree C
- Automatic Drain Valve provided in all Models
- Normal working Pressure : Max. 12 Kg/Cm2
- High pressure models up to 50 Kg/Cm2 are also available.
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| The theory behind operation of Heatless Dryers, is very simple. Chemicais which have the capacity to adsorb moisture on its surface. These adsorbents are used to dry the air. The adsorber are packed into two columns. The Cornpressed air is passed through this Column of packed adsorbent / dessjcant. It is obvious that after a certain period or drying (i.e. few hours / few minutes) the dessicant looses its capacjty to adsorb more moisture and hence is not capable of drying any more air, in its present Condition.The drying Capacity of the dessicant is restored by the process of regeneration. |
| This process involves purging out the moisture from the saturated dessicants with the help of the nearly 15% of the air that has already been dried. |
| All Heatless dryers are provided with 2 (two) towers packed with dessicant (adsorbent). At any given moment, during the operation of the dryers, one tower of dessicant is drying the compressed Air and the other tower of dessicant is being regenerated. The time period for drying and reactivation is equal. |
| The 3 major types of dessicants used in lndia are Silica Gel, Activated Alumina and Molecular sieves. |
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Heatless Air Drier |
Refrigerated Air Drier |
| Dew Point Atmospheric : - 40 Degree C |
Dew Point Atmospheric : - 23 degree C |
| Moisture Content in comp. Air : 80 ppm |
Moisture Content in comp.Air : 700 ppm |
| Purge Air loss : 15 % of compressed Air |
Purge Air loss : Nil |
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| Compact Series |
| Model |
Capacity (CFM) |
| CHL-10 |
10 |
| CHL-20 |
20 |
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| Standard Series |
| Model |
Capacity (CFM) |
| HL-15 |
15 |
| HL-35 |
35 |
| HL-50 |
50 |
| HL-75 |
75 |
| HL-100 |
100 |
| HL-150 |
150 |
| HL-200 |
200 |
| HL-300 |
300 |
| HL-500 |
500 |
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Max.Working Pressure : 12 Kg/Cm2
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