Internally Heated Air Dryer

Internally Heated Dryers

When there is less compressed air to spare, Van Air heated regenerative compressed air dryers provide the solution by requiring less purge air for desiccant regeneration. Compared to a heatless dryer, a Van Air internally heated dryer delivers significant savings through purge air reduction.

Van Air HI series internally heated desiccant dryers supply -40°F pressure dew point air for critical requirements for pneumatic instruments, controls and sensitive process air.

Principle of operation: Wet inlet air flows through the drying tower where moisture is attracted to and adsorbed on the desiccant. Approximately 6% of the dry outlet air, expanded to atmospheric pressure, is diverted to the regenerating tower where it is heated as it flows through a heater isolation tube. This air is then directed through the desiccant bed where it strips off accumulated moisture. Standard units available from 150 SCFM to 3,000 SCFM. Finally, the purge air is exhausted into the atmosphere through a purge valve. The eight-hour NEMA cycle includes four hours of drying, three hours of regeneration and one hour of cooling per tower.

All HI series compressed air dryers include individual heater thermostats. Purge flow rates are adjustable for your operating requirements.

Features and Benefits

• Standard designs 150 to 3000 scfm
• On/off switch
• Power on light
• Heater on light
• Activated alumina desiccant
• Desiccant fill/drain ports
• Stainless steel desiccant screens
• Rigid copper pilot air lines
• Control air filter
• 460V/3PH/60HZ supply power
• 115V control voltage transformer
• Permanently lubricated inlet transfer valve with position indicator and depressurization safety
• Purge flow control valve with pressure gauge for flow indication
• Purge exhaust mufflers
• PLC timer with manual & fast advance & hold switches
• NEMA 1 control enclosure
• Heater power and control power fuses
• Heater contactors
• Heater safety guards
• Adjustable heater thermostats
• -40°F dew point
• Interlock Logic valve sequencing
• Tower mounted pressure and temperature gauges
• Controlled repressurization and depressurization
• ASME coded pressure vessels
• Enamel exterior finish
• Tower lifting lugs
• Fail to switch light and common alarm contact

Optional Equipment

• NEMA 4 control enclosure
• Color changing moisture indicator
• Mounted filters and bypass piping
• Audible alarm
• Full flow safety relief valves
• Digital dew point readout
• Energy saver light
• Sequence lights left/right tower regenerating and/or drying
• Dew point demand switching (light and common alarm contact), recommended to minimize temperature spikes at tower switchover

Applications

• Installations where reduced purge air is required
• Installations where -40F pressure dew point is required