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| Internal
Heat Re-activated Dryers |
Heat
Reactivated dryers are used when one needs compressed air
of very low Dew point of (-)60oC or (-)80o
Deg C. In this design, the desiccant is regenerated at higher
temperature, along with small quantity of Dry air purge. Due
to purging with Dry air and thermal regeneration, residual
moisture loading on desiccant becomes low and this gives very
low Dew point.
The Drying
unit has 2-vessels filled with Activated Alumina or Molecular
sieves desiccant. One vessel remains in drying cycle for 4
hours, while other vessel is simultaneously regenerated at
atmospheric pressure. Around 3% flow of dryer capacity is
used as purge for regeneration. Electrical heaters are provided
in a central finned Stainless steel pipe in both drying vessels.
Heating cycle is for 2 hours and in this time hot purge air
increases desiccant temperature to around 100oC.
At this temperature regeneration is complete (due to dry air
purge). Dew point achieved is around (-)40oC. If
still lower Dew point is required, air purging rate
is slightly increased to 5% for (-)60oC and to
7.5% for (-)80oC Dew point. |
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A Pre-filter
with automatic drain valve is provided to remove any physical
moisture from compressed air before entering Air dryer. A
micronic filter is also provided in the Dryer outlet to arrest
any desiccant dust particles, up to 1 micron size. Thus, you
get absolutely “Clean & dry compressed air”. |
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A fully
Automatic unit requiring no attention of the operator.
Heaters switch ON/ off and all valves operate automatically.
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Pressure
is equalized to line pressure before changeover of drying
vessels. This prevents pressure and flow surge, and,
desiccant dusting |
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Low
purge air requirement in comparison to Heatless type
dryer. |
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Desiccant
life is around 5 years. |
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Internal
heaters provide maximum heat transfer efficiency resulting
in lower power requirement.
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Counter
current heated dry purge air provides maximum removal
of moisture with minimum gas purge loss. |
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Heaters
are not in physical contact with the desiccant.
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Standard
units are designed to deliver dry gas / air of (-)400C
Dew Point. By using more purge airflow, and using Molecular
sieves, Dew point of (-) 800C can be achieved. |
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| Air
capacity |
: |
5 to 5000 NM3/ Hr. |
| Dew point |
: |
(-)40oC
to (-)80oC. |
| Operating pressure |
: |
2 to 50 kg/ cm2g. |
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