HD Series Heatless Dryers

HD™–Series Heatless Dryers



Further Information:

Perma Pure HD-Series heatless dryers are ideal for low flow air drying operations. Dryer operation is fully automatic, and outlet dew points as low as -50°C can be achieved.

HD Heatless Desiccant Dryers dryers consist of two chambers filled with highly adsorbent desiccant. The standard desiccant is molecular sieve 4A. One chamber dries the gas stream while the opposite chamber is regenerated (purged). Purge air is a small portion of dried air taken from the drying chamber, expanded to atmospheric pressure and flowing counter-current through the regenerating (wet) chamber. Wet purge air is released from an exhaust port in the vapor state so that no drain is required. Purge air volume is controlled with an orifice housed within the unit. Purge air may be vented directly into the surrounding atmosphere, or it may be piped to a remote location. Once electrical power and air pressure are supplied to the dryer, it is ready to be used.

There are two models available. The 7″ model is best for flows under 60 liters per minute, while the 12″ version is recommended for flows of up to 90 liters per minute. The 12″ model is also recommended for applications requiring dew points below 40°C.

Air Requirement Oil-Free, Non-Condensing Air
Inlet Pressure 60-100 psig
Inlet Temperature 43°C Maximum
Purge Usage Approximately 10% of the inlet flow
Inlet/Outlet Connections 1/4″ Compression Fittings
Depth 5.625″
Model Number HD-2000-06-110 or (-220 for 220 VAC) HD-2000-12-110or (-220 for 220 VAC)
Inlet Flow Rate 0-60 LPM 0-90 LPM
Outlet Dew Point -40°C -50°C
Weight 8 Lbs. 12 Lbs.

Electrical Connection

The Heatless Dryer requires 110 VAC/60Hz or 220VBAc/50Hz, depending upon model.

Piping Connections

A compressed air line supplying between 60 psig and 100 psig should be connected to the 1/4″ wet air inlet port located between the two solenoid valves. The 1/4″ polypropylene compression fitting is the dry air outlet port. This should be connected via 1/4″ tubing. If the length of tube exceeds 15 meters, 3/8″ tubing should be used. The purge air exhaust ports located at the center of the solenoid valve coil should be left open to the atmosphere to provide venting for the wet air exhaust. They can be piped to a remote location if desired. An inexpensive particulate after-filter may be used on the purge air exhaust to reduce noise.


Once electrical power and air pressure are supplied to the dryer, it is ready for use. The dryer will operate indefinitely assuming a few precautions are taken. The number one cause of failure is compressor oil contamination of the drying media. A coalescing oil/water pre-filter is recommended for installations where oil or water mist is present.

HD Series Heatless Dryer Maintenance Items

ITEM # Description
HD-AR Molecular sieve absorbent replacement, 1 refill
100025 O-Rings, EP
HD-2000-02-09 Disk,Filter,HD