CDHT Series Desiccant Dryer
Since 1854, CURTIS Air Compressors has earned the reputation of building the most rugged industrial duty equipment you can buy. Today, FS-Curtis continues that reputation with the CDH Series. Heatless/pressure-swing, twin tower desiccant dryers produce consistent outlet pressure dew points down to -100F (-73C) for ultra-dry air. Built with the Latest Technology and on a Strong Tradition.
OPERATION SEQUENCE
1) Wet, compressed air enters the bottom of dryer and is directed up through
tower 1 by an inlet switching valve.
2) Air is dried and then directed to top outlet port through check valve.
3) A small portion of dry discharge air is diverted through a purge orifice &
throttled near atmospheric pressure back down into tower 2. This dry low
pressure purge air regenerates the desiccant in tower 2 by carrying off the
water collected during the drying stage.
4) Purge air is then exhausted to atmosphere out the bottom of tower 2
through a purge/repressurization valve and purge muffler.
5) After regeneration the purge/repressurization valve closes and fully
pressurizes tower 2 to line pressure before going back on-line.
6) Inlet switching valve then opens to direct wet compressed air up through
tower 2 to be dried while tower 1 is being regenerated.
MINIMUM PURGE AIR USED, QUIET OPERATION
By saving the heat of adsorption, our design maximizes the purge air’s ability to carry off moisture in a counterflow arrangement. Our base mounted models use only 13.7% PURGE AIR, the lowest in the industry. All units come with heavy duty purge exhaust mufflers.
LONG LIFE ACTIVATED ALUMINA DESICCANT
Large bed size along with slow and complete regeneration of off-line tower prevents fluidization, desiccant movement and deterioration. This ensures maximum desiccant life. Activated alumina also has high crush strength and is abrasion resistant.
EASY TO MAINTAIN
Separate fill and drain ports are conveniently located for easy desiccant replacement. Stainless steel support screens and flow diffusers protect dryer control valves from contaminants and prevents channeling. Easily removed for cleaning.
PURGE ECONOMIZER CONTROL CDHL SERIES.
Solid state control maintains precise 10 minute cycles to achieve pressure dewpoints of -40F (-40C). Unit is also manually adjustable for 4 minute cycles if -100F (-73C) dewpoints are required. Off-line tower fully repressurizes before going on-line preventing downstream pressure loss.
THERMOSAVE ENERGY SAVING PURGE CONTROL CDHT SERIES. Microprocessor automatically matches purge air usage to dryer load capacity for additional energy savings. Device monitors changes in desiccant bed temperature. Example: at 50% dryer load, only 50% of normal purge air is used and a tower is able to stay on-line for 10 minutes instead of the usual 5. Temperature sensors require no calibration.
PRODUCT SPECIFICATIONS
ELECTRICAL CHOICE:
• 1/60/120 or 240
• 1/50/110 or 220
• (12-24 volt DC optional)
CONTROLS:
• On-off switch
• Tower status lights
• Cycle mode indicator lights
• Economizer indicator lights
• Purge flow indicator
• Switching failure alarm
• Tower pressure gauges
• Moisture indicator
– High dew point alarm optional
– High dew point indicator optional
NEMA 4 STANDARD (NEMA 7 optional)
WORKING PARAMETERS:
• Minimum working pressure 60 psig (10 min cycle)
• Minimum working pressure 80 psig (4 min cycle)
• Maximum working pressure 150 psig (250 psig optional)
• Maximum inlet temperature 120F
• Maximum pressure drop less than 3 psig
• Field adjustable for 10 or 4 minute cycles
AVERAGE PURGE FLOW RATE AT 100 PSIG:
• 13.7% regeneration +0.7% repressurization (10 min cycle)
• 13.7% regeneration +1.8% repressurization (4 min cycle)
OPTIONAL FILTRATION PACKAGES:
.01 MICRON COALESCING PREFILTER
1 MICRON AFTERFILTER
• Package 1 — Prefilter and afterfilter mounted without three valve bypass
• Package 2 — Prefilter and afterfilter mounted with three valve bypass
around complete system
• Package 3 — Prefilter and afterfilter mounted with three valve bypass for
each filter and complete system
