Frost detection system for refrigeration apparatus
First Claim
1. A system for detecting frost buildup on an evaporator of a refrigeration system having intermittent forced air flow across the evaporator, and for avoiding unnecessary defrost cycles due to transient fluctuations in air flow, comprising:
- air movement means for moving air across said evaporator, said air movement means operative intermittently;
air velocity sensing means for sensing air velocity adjacent the evaporator;
signal generating means in connection with said sensing means for generating at least one signal corresponding to the air velocity sensed by said sensing means;
processor means in connection with said signal generating means, and said air movement means;
memory means in connection with said processor means, said memory means adapted for storing a defrost initiation value;
said processor means programmed to receive said air velocity signal, to calculate said defrost initiation value as a function of said air velocity signal a predetermined time after said air movement means commences operation and when said evaporator is in a defrosted condition, and to transmit said defrost initiation value to said memory means for storage therein, said processor means further programmed to thereafter compare said velocity signal and said initiation value and generate a defrost cycle initiation signal when said velocity signal and said initiation value have a predetermined relationship.
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Accused Products
Abstract
Apparatus for detecting frost buildup on an evaporator (34) of a refrigeration system (10) includes an air velocity sensor (42) in the air flow path. The sensor is connected to an analog to digital converter (46) which delivers binary signals representative of air velocity to a microcomputer (50) which includes a processor and a memory. Microcomputer (50) is programmed to prompt an operator through a screen (56) at a user station (52) to input an air flow reduction factor at a keyboard (54). The microcomputer uses the air flow reduction factor and the velocity sensed when the evaporator is fully defrosted to calculate a defrost initiation value. When the air velocity sensed at the sensor is no longer greater than the initiation value the microcomputer generates a defrost initiation signal. The microcomputer also includes a timer clock and periodically prints at a printer (58) the time and the velocity sensed.
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Citations
8 Claims
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1. A system for detecting frost buildup on an evaporator of a refrigeration system having intermittent forced air flow across the evaporator, and for avoiding unnecessary defrost cycles due to transient fluctuations in air flow, comprising:
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air movement means for moving air across said evaporator, said air movement means operative intermittently; air velocity sensing means for sensing air velocity adjacent the evaporator; signal generating means in connection with said sensing means for generating at least one signal corresponding to the air velocity sensed by said sensing means; processor means in connection with said signal generating means, and said air movement means; memory means in connection with said processor means, said memory means adapted for storing a defrost initiation value; said processor means programmed to receive said air velocity signal, to calculate said defrost initiation value as a function of said air velocity signal a predetermined time after said air movement means commences operation and when said evaporator is in a defrosted condition, and to transmit said defrost initiation value to said memory means for storage therein, said processor means further programmed to thereafter compare said velocity signal and said initiation value and generate a defrost cycle initiation signal when said velocity signal and said initiation value have a predetermined relationship. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification