Electronic humidity control
OwnerMichael R. Levine, Allen M. Krassinventors
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Abstract
A control system for a humidifier, associated with a hot air furnace, that attains a high level of relative humidity without causing any condensation on the building interior by varying the level of operation of the humidifier as a function of the rate of heat loss from the building. Since the duty cycle of the furnace is a function of the rate of the heat loss, the system generates a digital signal related to the duty cycle and uses that signal to interrogate a digital memory storing a program of desired humidities for various duty cycles to output an instantaneous desired humidity signal which is compared with a measured humidity signal to develop an on/off control signal for the humidifier.
Claims19
A control system for a device for modifying the humidity of a contained air volume, the volume having its temperature controlled by an intermittently operative temperature modifying apparatus, comprising:
- means for generating a first electrical signal having a value which is a function of the duty cycle of the temperature modifying apparatus;
- means for receiving the first electrical signal and generating a signal representation of the desired relative humidity within the volume;
- means for generating a signal representative of the actual relative humidity within the contained air volume;
- and
- comparator means operative to receive the signal representative of the desired relative humidity within the volume and the signal representative of actual relative humidity within the volume and to control the operation of the device to maintain the actual relative humidity substantially equal to the desired relative humidity.
In a heating system for a contained volume including a heat source, an electrically energizable control for the source, and an electrically energized humidifier operative, when energized, to add moisture to furnace heated air, the improvement comprising:
- means for generating an electrical signal proportional to the duty cycle of the source;
- means operative to receive said duty cycle signal and to generate an electrical signal representative of the desired humidity;
- a humidity sensor operative to generate a signal proportional to the actual humidity in the heated volume;
- and
- a comparator operative to receive the signal representative of desired humidity and the signal representative of actual humidity and to control the energization of the humidifier to maintain the humidity within the volume at the level of the desired humidity signal.
In a humidifier system including a humidity sensor having switching contacts connected in the humidity energizing circuit, the improvement comprising means for measuring the duty cycle of an intermittently operative heater for the humidified volume, and means connected to the switching contacts for modifying their operation as a function of the duty cycle.
An electronic humidistat operative to be connected into a system including a thermostat controlled heat source and a humidifier in order to control the state of energization of the humidifier to maintain controlled levels of relative humidity in the heated and humidified air volume, comprising:
- means for generating a digital electrical signal representative of the actual relative humidity in said volume;
- means for generating a digital electrical signal representative of the duty cycle of the source;
- a memory operative to store a program of desired humidities for differing duty cycles;
- means for addressing the memory with the duty cycle signal to output a desired relative humidity signal;
- and
- a comparator operative to receive the desired relative humidity signal and the actual relative humidity signal to control the state of energization of the humidifier to obtain the desired relative humidity.
Dependencies are inferred from the claim text.