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Hankison®'s Heatless Desiccant Dryers
The HHS Series
Utilizing twin towers filled with premium grade activated alumina, Hankison® Heatless dryers are available with three application specific control systems designed to meet the needs of specific industrial applications with economy and performance.
Unit of Measure

Automatic Energy Savings

Energy Savings Control at Load 95%

N/A 741 USD

Energy Savings Control at Load 90%

N/A 1481 USD

Energy Savings Control at Load 85%

N/A 2222 USD

Energy Savings Control at Load 80%

N/A 2962 USD

Energy Savings Control at Load 75%

N/A 3703 USD

Energy Savings Control at Load 70%

N/A 4443 USD

Energy Savings Control at Load 55%

N/A 6665 USD

Energy Savings Control at Load 40%

N/A 8886 USD

Energy Savings Control at Load 25%

N/A 11108 USD






Inlet Flow Capacity at 100 psig (6.7 bar) Pressure

N/A 590 scfm1002 nm³/h


N/A 101 in


N/A 50 in


N/A 53 in

Inlet Connection Size

N/A 2 in

Inlet Connection Type


Outlet Connection Size

N/A 2 in

Outlet Connection Type



N/A 1473 lb

Note for Connections

N/A BSP and DIN flanges available.
Maximum Standard Working Pressure1 N/A 150 psig10.5 bar

Maximum Optional Working Pressure

N/A 250 psig17.6 bar

Minimum Operating Pressure

N/A 60 psig120 psig150 psig250 psig4.2 bar8.4 bar10.5 bar17.6 bar

Maximum Inlet Air or Ambient Air Temperature

N/A 120 ºF49 ºC

Pressure Drop at Rated Flow

N/A ≤ 5 psi≤ 0.35 bar

Available Voltage

N/A 100 to 240 V


N/A 1


N/A 50 to 60 Hz

Direct Current (DC) Voltage

N/A 12 to 24 V

Industry Standards/Certifications

N/A ASME Approved CRN NEMA 4


N/A Industries such as pharmaceutical manufacturing, laboratories, hospitals, microelectronics, food packaging, paper, glass and powder painting with low dew point requirements, utilize heatless desiccant air dryers.

ISO 8573.1 Quality Classes

Dew Point

N/A -100 ºF-40 ºF-4 ºF38 ºF-73 ºC-40 ºC-20 ºC3 ºC

Remaining Moisture at Dew Point -100 ºF (-73 ºC)

N/A 0.12 ppmw0.15 mg/m³

Remaining Moisture at Dew Point -40 ºF (-40 ºC)

N/A 10 ppmw12 mg/m³

Remaining Moisture at Dew Point -4 ºF (-20 ºC)

N/A 81 ppmw97 mg/m³

Remaining Moisture at Dew Point 38 ºF (3 ºC)

N/A 610 ppmw730 mg/m³

Cycle Time for ISO Quality Class 1

N/A 4 min. Fixed

Cycle Time for ISO Quality Class 2

N/A Demand 10 min. Fixed

Cycle Time for ISO Quality Class 3

N/A Demand 16 min. Fixed

Cycle Time for ISO Quality Class 4

N/A Demand 24 min. Fixed

Precision Performance

Industry-Leading Design

  • Consistent outlet pressure dew points
  • Premium grade desiccant beads enhance surface area and have high crush strength
  • Large desiccant beds ensure 4.8 seconds of contact time
  • Large flow diffusers ensure even flow distribution through the bed and eliminate channeling
  • Towers are designed to prevent fluidization of the desiccant
  • Up-flow drying allows water and heavy contaminants to drop out of the air stream
  • Simple discharge of contaminants
  • Cleanable stainless steel flow diffusers/support screens
  • Separate fill and drain ports for ease of desiccant replacement

Integrated Filtration

  • Optional pre-filter and after-filter packages, featuring Hankison® NGF Series filters, can be pre-installed at the
    • Grade SF and Grade HF pre-filters are recommended for -40 ºF to 38 ºF (-40 ºC to 3 ºC) dew points
    • Grade PF and Grade UF pre-filters are recommended for -100 ºF (-73 ºC) dew points
    • Grade PF and Grade CF are the recommended after-filters

Precision AccuShift™ Switching Valves

  • Automatically shift to the low pressure side of the circuit to control process flow
  • Position memory ensures drying continues even without power
  • 5 year AccuShift™ valve replacement warranty (Dryer must be protected by properly sized Hankison® prefilter. Parts and labor covered through first year of warranty, parts only in second through fifth years.)
  • Three-way pilot operated solenoid valves manage the pilot air flow to direct the purge/repressurization valves
  • Purge pressure adjustment valve

Engineered-to-Order Options

  • High dew point alarm which includes light and voltage free contacts for remote alarm
  • Dew point monitor, includes digital display, voltage-free contacts and recorder output
  • Low ambient packages, epoxy paint, severe environment protection
  • Oil-free packages with integrated activated carbon towers

Safety Built to Code

  • Pressure vessels are CRN and ASME Certified
  • Heavy-duty mufflers for quiet operation
  • NEMA 4 electrical construction is standard
  • Pressure relief valves are standard

Application Specific Designs

How it Works

  • Phase 1 - Moist, filtered compressed air enters the pressurized on-line desiccant-filled drying Tower 1 through the AccuShift™ valve (A).
  • Phase 2 - Up-flow drying enables the desiccant to strip the air stream of moisture. Clean, dry compressed air exits through AccuShift™ valve (B) to feed the air system.
  • Phase 3 - When in regeneration mode, Tower 2 depressurizes to atmosphere through the muffler (C) when the valve (D) opens.
  • Phase 4 - A portion of dry compressed air (purge air) is diverted before exiting (B) and passes through off-line Tower 2 and exits at valve (D) to desorb the moisture from the desiccant. Once desorbed, valve (D) closes and Tower 2 is repressurized.
  • Phase 5 - At tower shift-over, valve (E) will open, causing AccuShift™ Valves (A & B) to shift.
  • Phase 6 - Tower 2 will be placed on-line to dry the bed. Operations will switch and Tower 1 will be regenerated.

Match Performance by Demand

N/A Three user selectable designs engineered to balance economy and performance.

Ideal for applications that operate with a large swing in air demands due to variations in production scheduling or shifts of operation. Some applications operate at a fraction of the flow of the compressor due to air system efficiency improvements. Some applications operate continuously at-or-near full capacity.

Automatic SensaTherm® Energy Savings

Automatic SensaTherm® Energy Savings

N/A Hankison®'s HHS Series with patented SensaTherm® automatically matches purge air to plant air demand. This ensures maximum performance as the saved energy goes right to your bottom line.

When operating at reduced capacity, the on-line drying tower remains active longer, until its full drying capacity is utilized. Desiccant bed temperature changes are constantly monitored within each tower to precisely manage drying times and reduce purge air consumption.

SensaTherm® also measures the increase in desiccant bed temperature (heat of adsorption) during the drying stage and the decrease in desiccant bed temperature (heat of desorption) during the regeneration stage. These temperature changes are accurate indicators of the moisture load on the dryer. This data is interpreted by microprocessor based controls to determine how long a tower stays on-line during the drying stage.



  1. Temperature transducers (thermistors) are used as sensing devices. They are simpler, more reliable and rugged than those others use.
  2. Sensors require no calibration.
  3. The system is based on saving the heat of adsorption, towers switch before heat's lost maximizing purge air efficiency and minimizing the amount of purge air required.

Controller Features

Controller Features

  • Choice of four operating modes
  • SensaTherm® Demand mode
  • Switches for On/Off, Alarm and Service reminder reset
  • Operational LED lights for power-on, tower status, valve status, and tower pressure
  • Service reminder LED lights for filters and drains, valves and desiccant. The user selects between a Normal and a Severe service interval
  • Alarm LED for tower switching failure, filter monitor signals, electronic demand drain alarms on filters
  • Vacuum fluorescent text display communicates energy savings, operating mode and service reminders
  • RS-232 communications port is standard

Inlet Flow

Inlet Flow

N/A Inlet flow capacities are established in accordance with CAGI (Compressed Air and Gas Institute) standard ADF-200: Inlet air pressure 100 psig (6.7 barg), inlet temperature saturated at 100 ºF (38 ºC). To determine inlet flow at pressures other than 100 psig (6.7 barg), multiply inlet flow at 100 psig (6.7 barg) from Product Specifications by the corresponding multiplier.

Four Dew Point Options per ISO 8573-1 Air Quality Standards

Four Dew Point Options per ISO 8573-1 Air Quality Standards

N/A Specifying a pressure dew point is not simple work for an engineer. Hankison® Heatless dryer designs allow you to optimize performance and dew points in the field to adapt to your environment and meet the following ISO 8573-1 Classes of air quality.

Dedicated to Excellence

Dedicated to Excellence

N/A Since 1948, compressed air users around the world have relied on Hankison® to provide innovative compressed air treatment solutions for critical applications.
Hankison® maintains a long standing reputation for manufacturing products that deliver superior performance, time proven reliability and optimal energy savings.
Hankison® today is the preferred choice for providing clean, dry compressed air for the most challenging industries.



N/A Dimensions and weights are for reference only. Request certified drawings for construction purposes.
  • 1 Units with higher Maximum Working Pressures are available.