Installation Instructions Type 1940 Automatic Dehydrator

Bulletin 237051

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Description This automatically operated dehydrator is designed to supply dry air under pressure to the transmission line of an antenna system. The dehydrator (Figures 1 and 2) basically consists of a motor-compressor unit and a dryer unit. They start operation when the transmission line pressure decreases to a preset level and stop when pressure increases to a preset level. The motor-compressor unit is shock-mounted to reduce vibration. The compressor has one single-stage cylinder. The dehydrator is designed to produce a maximum outlet pressure of 9 psi (62 kPa) with a maximum dew point (the temperature at which air becomes saturated and moisture condenses) of -40°F (-40°C) at the outlet. Since the compressor has low-friction piston rings and the motor has sealed bearings, no lubrication is required. The air intake filter assembly at the top of the compressor should be

replaced at least once a year to ensure efficient operation. Two adsorption cylinders in the dryer unit hold the desiccant in which air drying takes place. During operation, a timing motor controls two input solenoid values for the alternate drying of air in one cylinder and purging of moisture from the other cylinder. The front panel controls and indicators include a humidity indicator, illuminated circuit breaker, and pressure gauge. The humidity indicator contains a visible layer of silica gel style desiccant that changes color according to the relative humidity in the outlet line of the dehydrator. A deep blue color indicates 10% relative humidity or less, lavender indicates 30%, and pink indicates 50% or more.

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