Charge/purge control system for air dryer with humidity control
First Claim
1. Compressed air system comprising an air compressor for compressing air, a storage reservoir for storing compressed air, said air compressor having a compressed air outlet connected to said storage reservoir and disabling means responsive to a compressor control signal for disabling said air compressor when the pressure level in the storage reservoir attains a predetermined pressure level and for again enabling said air compressor when the pressure level in the reservoir drops to a predecided pressure level, an air dryer connected between the compressed air outlet and said storage reservoir for removing entrained moisture in the compressed air communicated to said storage reservoir, said air dryer including a desiccant requiring periodic purging when said compressor is disabled, purge valve means responsive to a purging control signal for purging said desiccant, pressure sensing means for generating a pressure signal which varies as a function of the pressure level in the reservoir, means responsive to said pressure signal for generating a pressure control signal when the pressure level in the reservoir increases above said predetermined level and terminating said pressure control signal when the pressure level in the reservoir drops below the predecided pressure level, and timer means for generating a timer signal for a predetermined time period after generation of said pressure control signal, means for generating said purging control signal in response to said timer signal, and means for generating said compressor control signal in response to either said timer signal or said pressure control signal.
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Accused Products
Abstract
A compressed air system includes an electronic control which controls enabling and disabling of the compressor in response to pressure level variations in the system storage reservoir. A humidity sensor is installed in the system reservoir and generates a signal which varies as a function of the humidity of the compressed air in the reservoir. The control unit includes a comparator which compares the signal generated by the humidity sensor with a reference signal and generates a humidity control signal when the humidity of the air in the reservoir exceeds the reference level. The control unit responds to compressor disabling by causing the system air dryer to regenerate or purge for a predetermined time period, even if the compressor is unloaded for time periods greater than the predetermined time period.
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Citations
17 Claims
- 1. Compressed air system comprising an air compressor for compressing air, a storage reservoir for storing compressed air, said air compressor having a compressed air outlet connected to said storage reservoir and disabling means responsive to a compressor control signal for disabling said air compressor when the pressure level in the storage reservoir attains a predetermined pressure level and for again enabling said air compressor when the pressure level in the reservoir drops to a predecided pressure level, an air dryer connected between the compressed air outlet and said storage reservoir for removing entrained moisture in the compressed air communicated to said storage reservoir, said air dryer including a desiccant requiring periodic purging when said compressor is disabled, purge valve means responsive to a purging control signal for purging said desiccant, pressure sensing means for generating a pressure signal which varies as a function of the pressure level in the reservoir, means responsive to said pressure signal for generating a pressure control signal when the pressure level in the reservoir increases above said predetermined level and terminating said pressure control signal when the pressure level in the reservoir drops below the predecided pressure level, and timer means for generating a timer signal for a predetermined time period after generation of said pressure control signal, means for generating said purging control signal in response to said timer signal, and means for generating said compressor control signal in response to either said timer signal or said pressure control signal.
- 10. Compressed air system comprising an air compressor for compressing air, a storage reservoir for storing compressed air, said air compressor having a compressed air outlet connected to said storage reservoir and disabling means responsive to a compressor control signal for disabling said air compressor when the pressure level in the storage reservoir attains a predetermined pressure level and for again enabling said air compressor when the pressure level in the reservoir drops to a predecided pressure level, an air dryer connected between the compressed air outlet and said storage reservoir for removing entrained moisture in the compressed air communicated to said storage reservoir, said air dryer including a desiccant requiring periodic purging when said compressor is disabled, purge valve means responsive to a purging control signal for purging said desiccant, and humidity control means for sensing the humidity of the compressed air in said system and generating said purge control signal and said compressor control signal to unload said compressor and purge said air dryer when the humidity of the compressed air in the system exceeds a predetermined level.
Specification