Regenerative Desiccant Dryers

Externally Heated Air Dryer

Van Air HB series blower purge regenerative compressed air dryers process larger volumes of compressed air economically, using no compressed air to regenerate the desiccant bed. An externally mounted blower and heater drives hot atmospheric purge air through the desiccant in the off stream tower. A -40°F protects critical equipment and processes.

All Van Air HB series dryers include: fully jacketed insulation on both towers and heater for greatest safety and operating efficiency; a centrifugal blower (3000 scfm and up); Interlock Logic valve control; failure to switch/purge alarm and contact; and polishing purge selector to minimize dew point spikes.

Principle of operation: Wet compressed air is directed through the drying tower where moisture is adsorbed on the desiccant. In the regenerating tower, moisture is stripped from the desiccant by atmospheric air drawn in through the blower and passed over the heater. As the hot purge air flows through the bed, it collects moisture and is discharged through the purge valve(s). The eight-hour NEMA cycle includes four hours of drying, three hours of regeneration and one hour of cooling per tower.

Features and Benefits

• Standard designs 350 to 5,000 scfm (larger units available)
• Fail to switch light & common alarm contact
• On/off switch
• Power on light
• Heater on light
• Blower on light
• Activated alumina desiccant
• Desiccant fill/drain ports
• Stainless steel desiccant screens
• Rigid copper pilot air lines
• Control air filter
• Aluminum jacketed tower, heater and hot piping insulation
• 460V/3PH/60HZ supply power
• 115V control power (Control voltage transformer)
• Permanently lubricated inlet transfer valve with a position indicator and depressurization safety
• Purge exhaust mufflers
• PLC control with manual fast advance & hold switches
• NEMA 1 control enclosure
• Heater power and control power fuses
• Heater and blower contactors
• Adjustable heater thermostat
• Polishing (cool down) purge selector
• -40°F dew point
• Interlock Logic valve control
• Tower mounted pressure and temperature gauges
• Controlled re-pressurization and depressurization
• Blower motor thermal overload protection
• Blower inlet filter
• ASME coded pressure vessels
• Enamel exterior finish
• Tower lifting lugs

Optional Equipment

• NEMA 4 enclosure
• Color change moisture indicator
• Mounted filters and bypass piping
• Audible alarm
• Full flow safety relief valves
• Digital dew point read out
• Dew point demand switching, recommended to minimize dew point spikes at tower switchover
• Energy saver. A thermostat registers a rise in purge air outlet temperature, which indicates the bed is regenerated, so the heater is turned off. The relay is automatically reset at the end of the cycle.
• High dew point indicator
• Sequence lights left/right tower regenerating and/or drying
• Steam regeneration

Applications

• Compressed air systems where a -40°F pressure dew point is critical and where no excess air can be spared for desiccant bed regeneration