Features:
· Air dryers are available with AutoDew, energy saving purge air control and adjustable dewpoint monitor
· 2 year warranty on all dryer switching valves
· Continuous removal of water vapor from compressed air
· Dewpoints of -400C (-40O F),or lower, at line pressure
· Fully assembled, packaged units complete with desiccant, ready for operation
· Low power requirements -220 Volt/50hz, single phase electrical input
· Coalescing prefilter and particulate afterfilter mounted and prepiped |
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Advantages:
·Dry air prevents corrosion in air operated instruments, tools and valves
·Reactivation of the moisture adsorbing desiccant without the use of heat
·Low pressure dew points eliminate condensation of moisture and freeze-ups
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General
Principle of operation
Heaterless dryers are fully automatic, dual-tower desiccant dryers for the continuous dynamic adsorption of water vapor from compressed air. Continuous drying is accomplished by the operation of two desiccant towers. Air is being dried under pressure by passing through one desiccant bed while the other bed is being reactivated.
Reactivation
As the name implies in a heaterless dryer, reactivation of the wet desiccant is accomplished without the use of heat. A small portion of the dried process air, called purge, is passed through the wet desiccant bed at near atmospheric pressure. This super dry air strips the desiccant of all water vapor previously adsorbed.
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Automatic Operation On A Fixed Time Cycle
All functions of the operation of the dryer are performed automatically on a fixed time cycle controlled by a PLC. Standard dryers operate on a 10 minute total cycle, 5 minutes for drying, 5 minutes for reactivation. Dryers with a 4 minute total cycle are designed for lower dewpoints. Switching air from one tower to the other is fully automatic. In order to prevent line surges and to minimize desiccant attrition, switching over from one tower to the other is carried out when both towers are at equal pressure. Both depressurization and purge flow are in a direction countercurrent to drying.
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Automatic Operation With AutoDew
With the energy saving AutoDew feature, the effluent dewpoint performance of each desiccant tower is monitored on a continuous basis. The dryer outlet dewpoint can be observed on a direct reading digital
dewpoint meter located at the dryer control panel. Should a good dewpoint be indicated, the electronic controls of AutoDew prevent the respective purge exhaust valve from opening and the purge cycle will not take place. The desiccant tower remains in standby in the repressurized state. All dry compressed air normally utilised for regeneration will be saved. For extensive details on the AutoDew control ask for the
HY Bulletin.
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Standard Features
Dewpoints
Standard models are designed for a continuous dewpoint performance of -40oC (-40oF) at full pressure. Dryers are available with effluent dewpoints as low as -75oC (-100oF).
Counter-current
reactivation
Reactivation purge flow is counter-current to the direction of air flow during drying. This assures maximum removal of moisture from the desiccant bed and lowest dewpoints during the adsorption (drying) cycle.
Controlled repressurization
Prior to the switchover, the reactivated desiccant tower is repressurized to full line pressure to prevent line surges and minimize desiccant attrition.
Purge rate
The purge rate of dryers is controlled by an orifice, sized to suit the specific operating conditions.
Fail safe design
On power and/or pilot air failure, the purge exhaust valves close.The dryer will continue to deliver low dewpoint air for several hours.
Moisture indicator
A colour-change type moisture indicator is provided with all heaterless air dryers. It provides a visual colour indication on a continuous basis. AutoDew equipped dryers do not have the colour-change moisture indicator.
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Typical GW Dryer Flow Schematic
Typical flow schematic showing a HY heaterless dryer, upflow
design. Technical details will differ with the model of the dryer.
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Standard
· Prefilter with DPI and automatic float type drain mounted
· Fully automatic operation
· -40oF (-40oC) dewpoint at line pressure
· Afterfilter with DPI and vent valve mounted
· 10 minutes NEMA dryer cycle
· EEMAC 4/NEMA 4 electrical class, CSA approved
· 220/1/50 electrical input
· 150 psig (1035kpag) maximum design pressure
· Maximum pressure drop 5 psid (35 KPA) at rated flow
· Locally mounted chamber pressure indicators
· Chamber relief valves
· Moisture indicator, color change type
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Design Features
Desiccant towers
Designed and fabricated in accordance with the ASME code section VIII, Div. I. for unfired pressure vessels. All models feature separate desiccant fill and drain ports. Piping manifolds, gauges, etc. Do not have to be removed to either fill or drain the desiccant. Each chamber is equipped with a stainless steel desiccant support and diffuser screen.
Automatic switching valves
All models use (2) 2-way inlet switching valves, soft seated (Teflon) carbon steel body with stainless steel internals and 2-way purge exhaust valves.
Purge exhaust muffler
Each purge exhaust valve is equipped with a highly effective purge exhaust silencer to assure quiet tower depressurization |
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Dimensions and Capacities
GW |
-1/1 |
-3/1 |
-6/1 |
-10/1 |
-12/1 |
-20/1 |
-30/1 |
-40/1 |
-60/1 |
-80/1 |
-100/1 |
-150/1 |
-200/1 |
capacity(Nm3/min) |
1 |
3 |
6 |
10 |
12 |
20 |
30 |
40 |
60 |
80 |
100 |
150 |
200 |
connectionDN(mm) |
25 |
25 |
32 |
50 |
80 |
80 |
80 |
100 |
125 |
125 |
125 |
200 |
200 |
Lmm |
800 |
1000 |
1400 |
1517 |
1517 |
1930 |
1945 |
1995 |
2050 |
2350 |
2450 |
3000 |
3500 |
W mm |
410 |
500 |
530 |
577 |
577 |
694 |
718 |
774 |
1140 |
1170 |
1370 |
1800 |
2000 |
H mm |
1500 |
1600 |
1920 |
2275 |
2595 |
2840 |
2910 |
3105 |
3485 |
3450 |
3725 |
4700 |
4900 |
Inlet H2 mm |
120 |
120 |
160 |
160 |
160 |
200 |
200 |
200 |
310 |
310 |
310 |
500 |
500 |
Outlet H1 mm |
1440 |
1540 |
1850 |
2195 |
2515 |
2620 |
2810 |
3005 |
2908 |
2860 |
3123 |
3500 |
3500 |
Desiccant weight(kg) |
38 |
85 |
170 |
265 |
320 |
535 |
785 |
1045 |
1560 |
2045 |
2800 |
3800 |
4800 |
Dryer weight(kg) |
150 |
260 |
500 |
835 |
890 |
1190 |
1680 |
1990 |
2890 |
3845 |
4765 |
6700 |
8000 |
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