Zero purge air dryers
A zero purge dryer gives you -20 °C or -40 °C dew point without spending compressed air on regeneration. A conventional heatless dryer blows 15–20% of its rated air back to atmosphere to dry its desiccant. On a 37 Nm³/min dryer that is about ₹29–38 lakh of compressor power a year*. A zero purge dryer regenerates with a blower and heater and cools the tower in a closed loop, so the air your compressor made reaches your plant.
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Where it fits
- Pharma and vaccine plants that need ISO 8573-1 Class 2 (-40 °C PDP) process and instrument air
- Tyre, chemical and fertiliser plants running 24×7, where every Nm³ of purge costs power all year
- Plants replacing old heatless dryers, or adding capacity without adding a compressor
How it works
- Adsorption: wet air passes up through activated alumina or molecular sieve in tower A and leaves dry.
- Heated regeneration: a blower pushes ambient air through a heater and down through tower B, driving the moisture out.
- Closed-loop cooling: tower B is cooled without using product air, so purge loss is zero.
- Switch-over: towers change over on a controlled cycle; the dew point sensor confirms outlet quality.
AIRS HRB series at a glance
| Item | Detail |
|---|---|
| Type | Blower reactivated, heated, zero purge desiccant dryer |
| Dew point | -20 °C or -40 °C PDP (other on request) |
| Capacity | Sized to your compressor flow, inlet temperature and pressure |
| Controls | PLC with HMI, dew point display, alarms, remote monitoring option |
| Support | Sizing, GA drawing, installation supervision, commissioning, service from Ahmedabad |
Proof from the field
A leading tyre manufacturer in Maharashtra runs an AIRS HRB-ZW1100 zero purge dryer at -20 °C PDP. See the case study for the energy comparison against heatless, heated purge and blower purge dryers. Read the case studies
Questions buyers ask
How is a zero purge dryer different from a heatless dryer?
A heatless dryer regenerates with 15–20% of its dry air. A zero purge dryer uses a blower and heater instead, so no compressed air is lost.
Does a zero purge dryer use any power?
Yes, the blower and heater draw power during regeneration. In most 24×7 plants that is far less than the compressor power a heatless dryer's purge consumes. We show both numbers in your proposal.
Which dew point do I need?
Instrument air and most pharma process air: -40 °C PDP. General dry plant air that must not condense in winter or in an air-conditioned area: -20 °C PDP is often enough.
Can it handle Indian monsoon inlet conditions?
We size for your summer and monsoon inlet temperature, not the catalogue's 35 °C reference, using the OEM's correction factors.
What filters do I need?
A coalescing pre-filter (to protect the desiccant from oil) and a particulate after-filter (to stop desiccant dust). We supply both.
What is the payback?
It depends on your flow, hours and power tariff. Send your compressor details and we will calculate it within 48 hours.
Which areas do you serve?
Ahmedabad, Vadodara, Ankleshwar, Dahej, Vapi, Sanand, Halol and the rest of Gujarat, plus Pune, Aurangabad, Baddi and plants across India.
Get a sizing
Send us: compressor make and model, flow (CFM or Nm³/min), pressure, inlet temperature, dew point needed and running hours. Call or WhatsApp +91 84888 42227 or email support@airs.net.in.
*Basis: 37 Nm³/min dryer, 15–20% purge, 0.10 kWh per Nm³ of compressed air, 8,400 h a year, ₹10.3 per kWh. Your figure will differ.