Abstract: Apparatus for dehumidifying air comprising two cooling coils operable in a first mode for circulating coolant at a temperature above 32.degree. F. and below the dew point of the air through one of the coils and for circulating coolant at a temperature below 32.degree. F. through the other, and operable in a second mode wherein the circulation of coolant is reversed. In one version of the apparatus, shown in FIG. 1, air flows continuously in one direction first through one coil and then the other; in another version of the apparatus, shown in FIG. 3, the direction of air flow is also reversed.

Abstract: A defrost control for a heat pump system initiates a defrost of the outdoor coil when certain computed condition occur. The conditions include exceeding a limit as to the difference that may be permitted between the maximum indoor coil temperature occurring since the last defrosting of the outdoor coil and the current indoor coil temperature. The limit that may not be exceeded is computed as a function of the maximum indoor coil temperature occurring since the last defrosting of the outdoor coil.

Abstract: A defrosting control method wherein an indoor unit determines whether a drop in the temperature gradient of an indoor side heat exchanger has been caused by a heavy load protecting operation or frosting of the outdoor heat exchanger during a reverse cycle heating operation of a two-unit-type air conditioner. The defrosting control is not triggered when the heavy load protecting operation is being carried out, and the defrosting control is started when predetermined conditions are satisfied, including the temperature of the indoor heat exchanger being below a raised predetermined temperature during a heavy load protecting operating.

Abstract: An adaptive defrost control for a refrigerator is shown in which a single linear power supply (12) and microprocessor (U1) is used for both the adaptive defrost and cold control functions. According to a feature of the invention, a zero current crossing point switching scheme may be used to improve relay cycle life. According to another feature, a calibration procedure based on line frequency may be used to obtain multiples of a selected unit of time for any accumulated compressor run time and defrost heater energization times. According to another feature a sample and hold technique may be used to distinguish between noise and valid signals.

Abstract: The present invention relates to a method for alleviating a short-term "cold blow" effect in a heat pump heating system. According to a method of the invention, reversing of a system valve in response to the sensing of a defrost condition is delayed by a predetermined time. The amount of this delay time depends upon the amount of time required for a supplementary heating unit to achieve an output sufficient to offset the cooling effect resulting from there being a cold indoor coil.

Abstract: A defrost control for a heat pump system initiates a defrost when certain computed conditions are exceeded. The conditions include a limit as to the difference that may be permitted between the maximum temperature difference of two measured temperatures and the current difference of these measured temperatures. The two measured temperatures are the temperature of the indoor coil of the heat pump and the indoor air temperature of the air being heated by the indoor coil.

Abstract: A microwave heat pump defroster system, utilizing a magnetron tube, or other microwave energy generating device, for the application of heat to the external surfaces of the outside coil of an electric heat pump, while the heat pump is operating in the heating mode for the following purposes, (1) to defrost the outside coil of the heat pump, (2) to inhibit the accumulation of frost on the external surfaces of the outside coil of the heat pump, and (3) to allow heat so applied to the external surfaces of the outside coil of the heat pump to be absorbed into the heat pump system via the outside coil of the heat pump, in a manner that will improve the efficiency of the heat pump.

Abstract: The object of the present invention is to provide a defrosting device, for a low temperature display case, that can effectively prevent incomplete defrosting, and that can reduce the temperature increase in a storage chamber during defrosting to the minimum.According to the present invention, a defrosting device comprises: defrosting heaters provided in a duct; a first defrost recovery temperature sensor for detecting an air temperature in the duct; a second defrost recovery temperature sensor for detecting a temperature at the evaporator; and a controller for, during a defrosting operation for the evaporator, rendering the defrosting heaters conductive, supplying a high temperature refrigerant to the evaporator, and for rendering the defrosting heaters nonconductive, based on an output of the first defrost recovery temperature sensor, and halting a flow of the high temperature refrigerant to the evaporator, based on an output of the second defrost recovery temperature sensor.

Abstract: A receiver (4) is provided in a main line (9a) and a bypass passage (4a) having an open/shut-off valve (SV) is provided for introducing gas refrigerant in the receiver (4) into a low-pressure liquid line. A motor-operated expansion valve (5) is fully closed, the open/shut-off valve (SV) is opened, and then defrosting operation is executed. At the initial stage of the defrosting operation, the open/shut-off valve (SV) is closed. When a discharge-pipe temperature Td drops to or below a specified temperature, the open/shut-off valve (SV) is closed. When the discharge-pipe temperature Td rises to or above a specified temperature, the motor-operated expansion valve (5) is once opened to a specified opening. When defrosting operation is completed, the open/shut-off valve (SV) is opened in a heating cycle and the motor-operated expansion valve (5) is gradually opened.

Abstract: A controller for a heat pump system wherein the controller has a variable capacity control capability that responds to thermostat output signals. The variable capacity controller computes real-time performance parameters at variable capacity heating/cooling load conditions of the heat pump system. A defrost controller calculates an optimum heat pump operating time period between successive defrost cycles during a heating mode of the heat pump. Such values are calculated as a function of sensed time, temperature and variable capacity operating conditions which are calculated by the variable capacity controller. The controller preferably has a manual mode for verifying correct operation of each actuator of the heat pump system, as a function of a sequenced input signal, while the heat pump system is in a shutdown mode.

Abstract: An air conditioner having a fan motor brown-out control algorithm for increasing the air conditioner fan speed upon sensing a brown-out under-voltage condition is provided. The air conditioner has a power supply connected to an AC line voltage, a fan motor, a multispeed fan driven by the fan motor and means for sensing a brown-out condition of the AC line voltage. The sensing means is connected to the power supply and provides a signal indicative of a brown-out condition. The air conditioner also has means for increasing the speed of the fan in response to the sensed brown-out condition signal provided by the sensing means. In an embodiment, the air conditioner further has a microprocessor and related circuitry for adjusting the speed of the fan. In another embodiment, logic circuitry is provided instead of a microprocessor. A brown-out control algorithm for an appliance having a multispeed fan and components for operating the fan is also provided.

Abstract: An air conditioner for vehicles can operate at a dehumidifying-operation mode including at least a dry-cooling or a dry-heating mode. The air conditioner comprises a plurality of discharge ports including a defroster discharge port and discharge port switching dampers, a control system for opening at least the defroster discharge port for a predetermined time when the dehumidifying-operation mode is selected, and a control system for opening another discharge port determined in accordance with an operation mode and the like after the predetermined time has elapsed. When the dehumidifying operation is selected, at least the defroster discharge port is opened only for the predetermined time and temperature-conditioned air is discharged to the windshield from the defroster discharge port. After the predetermined time has elapsed, a discharge port in accordance with an operation mode is opened.

Abstract: A defrost control apparatus and method for controlling the defrosting of a cooling coil of a refrigerator by estimating a postpone defrost time to postpone the defrosting of the cooling coil in accordance with fuzzy logic reasoning. The fuzzy logic reasoning uses the total number of times a door on the refrigerator is opened and an outside temperature value related to the outside temperature as input variables. The fuzzy logic estimate is produced at predetermined time intervals after a compressor of the refrigerator has operated a predetermined time since the last defrosting. The defrost control apparatus counts the total refrigerator operating time period after the compressor has operated the predetermined time. The defrost control apparatus starts to defrost the cooling coil when the total refrigerator operating time period exceeds the postpone defrost time.

Abstract: Air drawn in by a fan 4 is cooled by evaporator coils 2 and re-warmed by a condenser 3. A microcontroller MC and sensor S reads the temperature of the incoming air at regular intervals, e.g. once every minute, and controls a compressor 1 to operates in successive run periods, during which the evaporator 2 removes moisture from the air, separated by defrost periods in which the compressor is switched off so that warm incoming air melts any ice on the evaporator. The temperature at the start of a run period determines the duration of the respective run period, and the temperature at the end of a run period determines the length of the following defrost period. The length of the run period is constant at low temperatures but increases to a longer constant period at higher temperatures. The length of the defrost period is a maximum close to freezing point, but is reduced by decreasing increments as air temperature increases. At higher temperatures the dehumidifier operates continuously with no defrost.

Abstract: Apparatus for providing integrated control of a space cooling system is disclosed. The apparatus receives inputs from a plurality of temperature sensors, including a temperature sensor for measuring evaporator superheat, space temperature and compressor discharge temperature. The control apparatus incrementally adjusts the position of the cooling system expansion valve to regulate evaporator superheat and compressor discharge temperature and cycles the outdoor condenser fan on and off to raise condenser pressure in response to a low condenser pressure condition. In one embodiment, the cooling system includes a plurality of evaporators and a corresponding plurality of controllers electrically interconnected in a series loop for controlling the expansion valves and defrost heaters associated with the respective evaporators.

Abstract: A method for determining the time to begin and end a defrosting cycle of an evaporator included within a refrigeration system. Decisions as to initiate and terminate defrosting operations are predicated on information about the external temperature of the system and measuring differences in the rate of change of temperature drop between non-iced and iced conditions.

Abstract: A defrost cycle controller for a system, comprising a circuit operatively configured to control operation of a compressor and a defrost heater including a timer module that can be used either as a variable timer controller, a real time controller, or a cumulative run time controller, by selective connection of feedback signals provided to the plug-in module from the compressor and the defrost heater.

Abstract: Methods and apparatus for defrosting the outdoor coil in a variable speed heat pump system including determining, after the end of the last preceding defrosting, the optimal time to begin the next defrosting, and then initiating the defrosting responsive to the time interval since the end of the last defrosting tsD, the averages, over time, of liquid line temperature LLT, speed ES of the engine that drives the compressor, and outdoor dry bulb temperature ODT. The defrosting includes switching the system to the defrost mode at a predetermined maximum engine speed, periodically measuring the time taken during the defrosting ttD and the liquid line temperature LLT; periodically computing the rate of change of LLT with respect to time .DELTA.LLT/.DELTA.t, and when .DELTA.LLT/.DELTA.t is greater than the previous maximum value and ttD is greater than a predetermined time, storing the value of each in place of its preceding value.

Abstract: A device and method is provided for automatically defrosting a refrigeration system. The present invention includes a microprocessor which initiates a defrost cycle during a time of day which is most efficient for the refrigerator and the utility company. Moreover, the defrost cycle is initiated during a time of day which has the least impact on food stored within the microprocessor. The microprocessor is programmed and enabled so as to analyze the power consumption of the refrigerator during a 24 hour period, and from this analysis, the microprocessor is able to determine the time of day and period(s) of time which will be most efficient for the initiation of a defrost cycle.

Abstract: An air conditioning apparatus includes an air duct having an inlet and an outlet supplying conditioned air, and an air conditioner for cooling and heating air using a refrigeration cycle. In the refrigeration cycle, the air conditioner includes a first heat exchanger, a second heat exchanger disposed on a downstream side of the first heat exchanger, and a compressor. The air conditioner selectively operates in a cooling mode where cool air cooled by the first heat exchanger is supplied through the outlet of the air duct, in a heating mode where hot air heated by the first heat exchanger is supplied through the outlet of the air duct, and in a dehumidifying mode where air cooled by the first heat exchanger and subsequently heated by the second heat exchanger is supplied through the outlet of the air duct.

Abstract: A defrost cycle controller for modifying the total length of time a compressor operates before a defrost cycle is initiated, wherein the time the compressor is on between defrost cycles is referred to herein as a frost accumulation period. A microprocessor includes means for deenergizing the compressor and coupling the defrost heater to a power supply when a continuous compressor run time exceeds a predetermined demand defrost time. The microprocessor further includes means for determining the time required to actually defrost the evaporator during a defrost operation, referred to herein as a defrost time, and means for modifying the frost accumulation period in response to the time to complete the defrost operation.

Abstract: A defrost control apparatus for refrigerator includes a microcomputer which counts the number of opening/closing times of a door of a storage room for each of time zones within a day so as to set indexes for every time zones on the basis of the number of opening/closing times. The microcomputer also counts operating hours of a compressor and total elapsed hours, and determines a sudden phenomenon and a season. The microcomputer further selectively fetches the indexes, and generates a single index by joining a plurality of indexes so as to apply the same to a neural network included in a defrost signal generating unit. The neural network generates a defrost on/off signal on the basis of inputted data. In addition, if feature amounts are generated on the basis of the indexes by a feature detecting unit, the neural network generates the defrost on/off signal on the basis of the feature amounts.

Abstract: An apparatus controls an appliance, the appliance including a compressor, a fan, and a heater. The apparatus includes a first switch for selectively coupling a first terminal with one of a second terminal and a third terminal in response to a first control signal. The first terminal is coupled with an energy source and the third terminal is coupled with the compressor. The apparatus further includes a second switch for selectively coupling the second terminal with the heater and the third terminal with the fan in response to a second control signal. The apparatus still further includes a control circuit coupled with the first switch and the second switch for generating the first control signal and the second control signal. A relay drive circuit couples relay coils in series to control the first switch, the second switch, and the third switch. A bypass switch allows a single current to selectively energize one or both relay coils.

Abstract: A defrost controller for a refrigerator/freezer including one or more of the following features: (1) a timer module that can serve as a real time, cumulative time or variable time defrost timer; (2) an algorithm to control defrosting in view of frequent power outages; (3) a power up defrost cycle; (4) a default reaction to loss of compressor run information; (5) a simple manufacturing test initiator; (6) a test initialization via thermostat actuation; (7) a relay power supply which supplies two different energization voltages; (8) a relay energization signal which decays rapidly from a voltage in excess of the relay rated voltage to a voltage within the relay rated voltage; and (9) respective relay energization sequence to overcome light contact welding.

Abstract: A defrost controller for a refrigerator/freezer including one or more of the following features: (1) a timer module that can serve as a real time, cumulative time or variable time defrost timer; (2) an algorithm to control defrosting in view of frequent power outages; (3) a power up defrost cycle; (4) a default reaction to loss of compressor run information; (5) a simple manufacturing test initiator; (6) a test initialization via thermostat actuation; (7) a relay power supply which supplies two different energization voltages; (8) a relay energization signal which decays rapidly from a voltage in excess of the relay rated voltage to a voltage within the relay rated voltage; and (9) respective relay energization sequence to overcome light contact welding.

Abstract: Control of defrost cycle initiation in a refrigeration apparatus is based on the difference between the last two defrost times, taking into account the sign of the difference so that the increase or decrease in the time between defrosts corresponds to the trend in defrost times rather than on any particular defrost time or the average of defrost times. A variety of limits are included to ensure that the time between defrosts is reactive to sudden aberrational changes in defrost times, and does not exceed minimum or maximum values.

Abstract: A controller for a gas heat pump system wherein the controller has a variable capacity control capability that responds to thermostat output signals. The variable capacity controller computes real-time performance parameters at variable capacity heating/cooling load conditions of the gas heat pump system. A defrost controller calculates a maximum heat pump operating time period between successive defrost cycles and a minimum heat pump operating time period of each defrost cycle, during a heating mode of the gas heat pump. Such values are calculated as a function of sensed time, temperature and variable capacity operating conditions which are calculated by the variable capacity controller. The controller preferably has a manual mode for verifying correct operation of each actuator of the gas heat pump system, as a function of a sequenced input signal, while the gas heat pump system is in a shutdown mode.

Abstract: A device and method is provided for automatically defrosting a refrigeration system. The present invention includes a microprocessor which initiates a defrost cycle during a time of day which is most efficient for the refrigerator and the utility company. Moreover, the defrost cycle is initiated during a time of day which has the least impact on food stored within the microprocessor. The microprocessor is programmed mid enabled so as to analyze the power consumption of the refrigerator during a 24 hour period, and from this analysis, the microprocessor is able to determine the time of day and period(s) of time which will be most efficient for the initiation of a defrost cycle.

Abstract: A method of energizing a relay comprising the steps of applying an energization signal to the relay having a voltage in excess of a rated voltage of the relay and then allowing the energization voltage to rapidly decay to a level within the rated voltage of the relay.

Abstract: A defrosting control unit for providing centralized control of the defrosting a showcase having showcase units with defrosting devices includes an environmental informer ion signal generation portion and a defrosting control portion. The signal generation portion generates a signal reflecting at least one environmental parameter such as whether it is daytime or nighttime, the difference in air temperature measured at different places in a showcase unit, the deviation of the temperature difference with respect to a steady-state value, and the temporal variation of the deviation. The defrosting control portion receives the environmental information signal from the signal generation portion and sends a defrosting start signal and a defrosting end signal to the defrosting devices at a time interval . The signal generation portion may include a fuzzy reasoning portion, membership functions, and rules so that an inference on the optimal time for starting a defrosting operation can be made.

Abstract: A defrost cycle controller for a system, comprising a circuit operatively configured to control operation of a compressor and a defrost heater including a timer module that can be used either as a variable timer controller, a real time controller, or a cumulative run time controller, by selective connection of feedback signals provided to the plug-in module from the compressor and the defrost heater.

Abstract: A defrost controller for a refrigerator/freezer including one or more of the following features: (1) a timer module that can serve as a real time, cumulative time or variable time defrost timer; (2) an algorithm to control defrosting in view of frequent power outages; (3) a power up defrost cycle; (4) a default reaction to loss of compressor run information; (5) a simple manufacturing test initiator; (6) a test initialization via thermostat actuation; (7) a relay power supply which supplies two different energization voltages; (8) a relay energization signal which decays rapidly from a voltage in excess of the relay rated voltage to a voltage within the relay rated voltage; and (9) respective relay energization sequence to overcome light contact welding.

Abstract: A method for controlling a defrosting operation of a refrigerator by providing a defrosting operation control method wherein a refrigerator use pattern by the user is learned. The defrosting operation control method based on the learning of the refrigerator use pattern comprises the steps of dividing a day, namely, 24 hours into a plurality of time intervals each corresponding to a predetermined period, for example, one hour, calculating the number of refrigerator door openings by time intervals, repeating the calculating step for predetermined days, storing information about arithmetic average values of the number of door openings calculated by time intervals, and performing a defrosting operation during the period that the refrigerator is not used by the user, based on the arithmetic average value information.

Abstract: A defrost recycle apparatus and method for use with a temperature control system is provided. The temperature control system includes a heat transfer unit for removing heat from an enclosed space. The temperature control system automatically defrosts the heat transfer unit based upon a default defrost control strategy. After the termination of a defrost operation initiated according to the default defrost control strategy, the defrost recycle apparatus determines if the defrost operation was successful (completely defrosted the heat transfer unit) based upon two parameters associated with the defrost operation. In the preferred embodiment, the defrost recycle apparatus determines the success of the defrost operation based upon the temperature in the vicinity of the heat transfer unit after a predetermined period of time has elapsed after the termination of the defrost operation.

Abstract: An air conditioning system includes a compressor which is reversed in order to switch from a heating mode to a defrost mode, or in order to switch between heating and cooling modes. Prior to being reversed, the compressor is automatically reduced to a slower speed greater than zero for a predetermined time period to minimize damage and noise when reversal occurs. The compressor is reversed while at the slower speed when switching the system to a defrost mode. When switching between heating and cooling modes, the compressor speed is first reduced to the slower speed for the first predetermined time period and then to zero speed for a second predetermined time period, before the compressor is reversed.

Abstract: The system is adapted for saving energy in an ambient air and conventional refrigeration system by independently controlling the compressor, evaporator fans and door heating unit in conjunction with the outdoor temperatures and the unit's internal temperature. The system also provides controls that provide for freeze up protection. The system can be adapted for use with walk in cooler units currently in operation to provide a system that can provide operational cost savings and increased efficiency for the operator.

Abstract: A defrost cycle for a heat pump system which optimizes the efficiency of the heat pump by initiating defrost depending upon the relationship of both the outdoor coil ambient temperature and the outdoor coil refrigerant temperature with a predetermined temperature reference level.

Abstract: A defrost controller for a refrigeration system. The system includes a circuit having a programmable controller which monitors compressor demand from a thermostat and uses alternating current cycles of a line voltage to control on and off cycles for a defrost mode of the refrigeration system. An anti-short cycle feature is optionally included to inhibit compressor operation for a predetermined interval each time the compressor is disabled.

Abstract: A refrigerator is defrosted by comparing a sensed temperature in the refrigerator with a predetermined temperature when a defrost start time is reached. If the sensed temperature is too high, a compressor is caused to operate in order to reduce the temperature to the predetermined temperature. Then, the open/closed conditions of the refrigerator doors are sensed, and the defrost heater is activated if the doors are sensed as being closed.

Abstract: The invention relates to methods of defrosting an evaporator coil of a transport refrigeration unit which includes microprocessor based electrical control. The electrical control maintains the temperature of a conditioned space at a predetermined set point temperature via hot gas heating and cooling cycles. The evaporator coil is defrosted to remove frost and ice by closing a damper to the served space and initiating a heating cycle. At the termination of defrost, a cooling cycle is initiated, but the damper is maintained in a closed position for a predetermined period of time to remove heat built up during the defrost process. The invention also detects damper malfunctions, including failure to close prior to defrost, and failure to open after defrost. The invention also evaluates manual and timed requests for a defrost operation, overriding the requests in response to predetermined conditions.

Abstract: A defrosting control method for an air conditioner wherein when the frost amount of an outdoor heat exchanger becomes an allowable value or more during a heating operation, a defrosting operation is performed for defrosting the outdoor heat exchanger. A time period is calculated which is required for a room temperature to reach a preset temperature after the start of the heating operation by an inverter running at one of a predetermined plurality step of frequencies, in accordance with an environmental condition data. A frost amount of the outdoor heat exchanger is calculated in accordance with the environmental condition data, under the condition that the inverter runs for the calculated time period. There is selected an inverter output frequency from the plurality step of frequencies, the inverter output frequency allowing each of the calculated amounts to take the allowable value or less, the allowable value being determined as a level indicating the defrosting operation is unnecessary.

Abstract: A adjustable defrost cycle for a heat pump system which ensures that the outdoor coil is maintained free of frost by adjusting a defrost initiation reference level for the initiation of the next subsequent defrost cycle depending upon the time period of the previous defrost cycle.

Abstract: A method of operating a transport refrigeration system having a refrigerant compressor driven by an internal combustion engine. Microprocessor based electrical control maintains the temperature of a conditioned space at a desired set point via heating, cooling and null cycles, with the engine being started and stopped, as required. During the engine starting process, a suction line modulation valve, if used, is closed, engine pre-heat time is selected, including using engine temperature to access a look-up table, and current draw is checked during pre-heat. Excessive current terminates pre-heat. Control diagnostics checks the voltage level on both sides of a refrigerant high pressure switch, before initiating engine cranking. Prior to stopping the engine, a control option initiates a heating cycle for a short time when null is being entered from a cooling cycle, to warm the evaporator and prevent premature starting of the engine.

Abstract: In multiple system type air conditioner, there are provided an auxiliary outdoor heat exchanger provided in an outdoor unit, and defrosting device that, on heating operation, periodically or as needed feeds the refrigerant discharged from the compressor to the outdoor heat exchanger and all the indoor heat exchangers. After the refrigerant has passed through the outdoor heat exchanger and all the indoor heat exchangers, the refrigerant returns to the compressors through the auxiliary outdoor heat exchanger.

Abstract: An air conditioning system including a refrigerant circuit having a compressor, a three port switching valve, a four port reversing valve, an outdoor heat exchanger, a first throttle device including a first decompression device, a second throttle device including a first decompression device, an indoor heat exchanger and an accumulator connected in series by use of refrigerant pipes; a first bypass circuit which is constructed to carry out heat exchange with the intake pipe connecting between the accumulator and the compressor, and which is connected as a bypass to the pipe connecting between the first and second throttle devices; a second bypass circuit having a check valve to bypass the first decompression device; a third bypass circuit having a check valve to bypass the second decompression device; a fourth bypass circuit which is connected as a bypass to the pipe between the first and second throttle devices, and which is smaller than the discharge pipe in inside diameter; and a fifth bypass circuit whic

Abstract: A defrosting controller for use with a refrigeration system determines calculating a frost melting period from the measurements of the evaporator temperature during defrosting by means of an evaporator temperature sensor, establishes a refrigerating operation rate which is the ratio of the period of the frost melting process to the (total) open period of an electronic motor-driven valve during the refrigeration, and then decides whether the next defrosting operation is to be skipped or not.

Abstract: A refrigerator having an enclosed compartment for storing food to be cooled, an evaporator including a refrigerant flowing therethrough for cooling the food in the compartment, a defrosting device, and a defrost override device. The defrosting device periodically heats the evaporator for removing the accumulated frost for controlled periods. The defrost override device automatically deactivates the defrosting device when the heating of the evaporator continues for longer than a preset time. The defrost override device may also automatically activate the refrigerant flowing through the evaporator. In this manner the refrigerator of this invention can store food without overheating during the defrosting operation.

Abstract: A low-temperature foods preserving case and a temperature control method therefor, in which a plurality of evaporators, each partitioned by partitioning panels, are arranged correctively in a cooling chamber, for which sequential cooling and defrosting operations are instructed by a timer, so that circulatory passage of the cooling air is formed through said cooling chamber, the foods preserving chamber, and the cooling chamber by means of fans installed in each of partitioned air passages separated by said partitioning panels.

Abstract: A refrigerating apparatus is conventionally provided with an electric which is fed with an electric current to effect heating and defrosting operations, a defrosting control device including a defrosting timer and an evaporator outlet refrigerant temperature detector for controlling the electric current fed to the electric heater, and an overheating preventing temperature detector for preventing the occurrence of abnormal overheating by the electric heater. The refrigerating apparatus of the present invention can regularly effect defrosting even if any anomaly should arise in the evaporator outlet refrigerant temperature detector. Specifically, the overheating preventing temperature detector is connected to the defrosting control device, and a detection temperature signal from either the evaporator outlet refrigerant temperature detector of the overheating preventing temperature detector is used to commence and terminate defrosting.

Abstract: A refrigerating machine (10) of the refrigerator or freezer type comprises a device (33) for defrosting cold parts to transform the ice into water to be discharged. It has an end-of-defrosting detector (20) comprising:(1) a reservoir (24) which receives the water to be discharged, one of the branches (23) of a siphon (21) extending into said reservoir in order to drain the reservoir when the water reaches the level required for activation of the siphon, the other branch (22) being situated externally of the reservoir,(2) a light barrier (27, 28), comprising a light source and a light receiver arranged around the other branch (22) of the siphon in such a way that the light beam of the light barrier is interrupted by the passage of water through said other branch while defrosting is in progress, and(3) a electric circuit (30, 31, 32, 34) which stops defrosting when the light beam is not interrupted for a predetermined time.