Call: 1-800-643-4330
Hankison®'s Heatless Desiccant Dryers
The HHL 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






Inlet Flow Capacity at 100 psig (6.7 bar) Pressure

N/A 115 scfm195 nm³/h


N/A 54 in


N/A 44 in


N/A 38 in

Inlet Connection Size

N/A 1 in

Inlet Connection Type


Outlet Connection Size

N/A 1 in

Outlet Connection Type



N/A 685 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 10 min. Fixed

Cycle Time for ISO Quality Class 3

N/A 16 min. Fixed

Cycle Time for ISO Quality Class 4

N/A 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
  • Three-way pilot operated solenoid valves manage the pilot air flow to direct the purge/repressurization valves
  • Purge pressure adjustment valve
    • 1 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.

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.

Controller Features

Controller Features

  • Choice of four fixed cycle operating modes corresponding to ISO 8573.1 Air Quality Classes
  • Choice of eight Purge Economizer Energy Savings settings
  • Switches for On/Off, Alarm and Service reminder reset
  • Operational LED lights for power-on, tower status, valve status, and tower pressure
  • Alarm LED for valve switching failure
  • RS-232 communications port is standard
  • Service reminder LED lights for filters and drains, valves and desiccant

Selectable Purge Economizer Savings

Selectable Purge Economizer Savings

N/A HHL Series provides user selectable energy savings with tailored drying cycles designed to match your peak air demands.

Reducing the amount of time the dryer spends purging in the regeneration cycle can save energy. Eight settings (0% to 70% in 10% increments) are furnished for users to lower the purge to match reduced air loads on the dryer. Each energy saving setting has an LED light which will illuminate when it is selected. Simply flip the switch to select the desired energy saving setting.

In addition, this state-of-the-art controller offers four pressure dew point settings to further tune your savings and adapt the system to your environment.

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.