JPH048708B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature display method for displaying the internal temperature of a cooler such as a refrigerator after defrosting is completed, and continuously operating the defrosting means until the internal temperature drops to a predetermined temperature. be.

Conventionally, in a temperature display method that includes both a display means for displaying the internal temperature of a refrigerator or the like on a display tube numerically, and an informing means for notifying defrosting by lighting up a diode at the time of defrosting, the informing means In some cases, abnormalities in the internal temperature of the refrigerator that occur temporarily and abnormalities in the internal temperature of the refrigerator due to malfunctions of the compressor, evaporator fan motor, etc. other than during defrosting were notified. On the other hand, even after defrosting is completed and the cooling operation is resumed, the internal temperature that rose during defrosting does not immediately drop to the set temperature, and the display means is activated or deactivated for a predetermined period of time after defrosting is completed. When the display means is activated, it is not possible to clearly determine whether the high temperature displayed is due to the completion of defrosting or a temperature due to equipment failure, and when the display means is deactivated, it is impossible to confirm the temperature inside the refrigerator.

The present invention improves the above-mentioned drawbacks, and one embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In Fig. 1, 1 is a temperature sensor such as a transistor, whose collector and base are connected to the output terminal and (-) side input terminal of an operational amplifier 2, and which detects the internal temperature of a refrigerator, etc., and when the sensor temperature rises. When the sensor temperature decreases, its impedance decreases and increases when the sensor temperature decreases. Reference numeral 3 denotes a resistor connected between the connection point between the base of the temperature sensor 1 and the (-) side input terminal of the operational amplifier 2 and the power supply terminal A, which determines the reference current of the temperature sensor 1. 4 is an operational amplifier which is connected between current terminals A and B and receives the power supply voltage from power supply terminal B.
Vc is powered. The (-) side input terminal of the operational amplifier 4 is connected to the output terminal of the operational amplifier 2 via an adjustment resistor 5 and a resistor 6, which are connected between the output terminal of the operational amplifier 2 and the power supply terminal A. There is. Incidentally, the adjustment resistor 5 is a resistor for making the display section (to be described later) display 0°C when the temperature sensor 1 is at 0°C. Reference numeral 7 denotes an adjustment resistor connected to a negative feedback circuit between the output terminal of the operational amplifier 4 and the (-) side input terminal, which adjusts the temperature of the temperature sensor 1 at high temperatures and the temperature displayed on the display section to be described later. The temperature characteristics of the temperature sensor 1 are determined by matching. 8 is an A/D converter that converts analog signals into digital signals;
Numerals 9 and 10 are decoder drivers with latches that convert digital signals into codes that can be displayed numerically on the display section 11 and output the codes. When a low level signal (hereinafter referred to as L signal) is applied to the terminals 12 and 13 of the decoder drivers 9 and 10 with latches, the output disappears.
It outputs when a high level signal (hereinafter referred to as H signal) is applied. The display unit 11 has a 4-digit fluorescent display tube using 7 segments arranged in an approximately 8-shape in each digit as a display means for displaying the temperature inside the refrigerator.For example, the temperature is displayed in the right two digits and the other digit. (-) (minus sign) display, and also has a lighting section 14 as a notification means for notifying defrost of the evaporator.
Power is supplied from the secondary side of 5 and power supply terminal B.
The A/D converter 8 is connected to a display section 11 via decoder drivers 9 and 10 with latches.
Resistors 16 and 17 are (+) of operational amplifiers 2 and 4, respectively.
side input terminal and reference voltage terminal 18 of A/D converter 8
is connected between.

An adjustment resistor 19 and a resistor 20 that determine the set temperature inside the refrigerator are connected in series between power terminals A and B.
Reference numeral 12 denotes a changeover switch having fixed contacts 22A, 22B, a fixed terminal 22C for displaying defrost alarm return temperature, which will be described later, and a movable contact piece 23. The fixed contact 22A is connected to the output terminal of the operational amplifier 4, and the fixed contact 22B is connected to the adjustment Between the resistor 19 and the resistor 20, the fixed contact 22C is connected to the (+) side input terminal of a buffer, which will be described later, and the movable contact piece 23 is connected to the input terminal 25 of the A/D converter 8. When the fixed contact 22A is closed, the display section 11 displays the temperature inside the refrigerator, when the fixed contact 22B is closed, the display section 11 displays the set temperature inside the refrigerator, and when the fixed contact 22C is closed, the display section 11 displays the defrost alarm. Displays the recovery temperature.

26 is a temperature control switch circuit. 27 is an operational amplifier, and the (+) side input terminal is a resistor 28
The (-) side input terminal is connected to the output terminal of the operational amplifier 4 via the adjusting resistor 19 and the resistor 20. A positive feedback resistor 29 is connected between the output terminal of the operational amplifier 27 and the (+) side input terminal, and the output terminal is connected to resistors 30, 3 connected in series.
1 to the power supply terminal A. NPN
The base of the type transistor 32 is connected to the resistor 30 and the resistor 3.
1, the collector is connected to the excitation winding 34 of the electromagnetic switch 33, and the emitter is connected to the power supply terminal A.

Reference numeral 35 indicates a fixed contact of the electromagnetic switch 33, and reference numeral 36 indicates a movable contact, which are interposed in the compressor operating circuit of the refrigeration system 37.

Figure 2 shows the defrost alarm circuit and defrost circuit, and the terminals A'', B'', C', D', E', F' are the terminals A', B', C, D, E, and They are each continued in F.

38 is a buffer, and 39 is an operational amplifier 40 which is a non-inverter. The (+) side input terminal of the buffer 38 is connected to the output terminal of the operational amplifier 4,
A negative feedback circuit is provided between the (-) side input terminal and the output terminal.

The output terminal of this buffer is connected to the (+) side input terminal of the operational amplifier 39 via resistors 41 and 42.

The (-) side input terminal of the operational amplifier 39 is connected to the fixed contact 22C through an adjustment resistor 43 and a resistor 44 connected in series between the power supplies, and the output terminal is connected to the defrost notification lighting section 14. It is also connected to the power supply terminal A via a series circuit of a diode 46 and a resistor 47. The adjustment resistor 43 is used to adjust the defrost alarm return voltage, and the defrost alarm return temperature that closes the movable contact piece 23 to the fixed contact 22C is displayed on the display section 11. Further, a positive feedback resistor 48 is connected between the output terminal of the operational amplifier 39 and the (+) side input terminal. The input terminal of the non-inverter 40 is a diode 46 and a resistor 4.
The output terminal is connected to the emitter of a phototransistor 52 which constitutes a photocoupler 51 via a series circuit with a diode 49 and a resistor 50, and via a series circuit with a reverse diode 53 and a resistor 54. It is connected to the emitter of transistor 52. In addition, the non-inverter 40 is a power supply terminal.
Power supply voltage Vc from power supply terminal B" provided between A" and B"
is supplied with power, and a feedback resistor 55 is provided between its output terminal and input terminal. Further, a capacitor 56 forming a time constant circuit together with a resistor 50 is connected between the input terminal of the non-inverter 40 and the power supply terminal A''.
is connected. In addition to the above-mentioned emitter of the phototransistor 52, the collector is connected between the output terminal of the buffer 38 and the input terminal of the inverter 57, and the photocoupler 51 is connected to the power supply terminal B.
When the light emitting diode 58 constituting the light-emitting diode 58 lights up.
Turns on and turns off when the light goes out. Inverter 5
7 is connected between power supply terminals A and B and is supplied with power supply voltage Vc. The output terminal of the inverter 57 is connected to the decoder driver 9, 10 with a latch, and when the signal from the emitter of the phototransistor 51 is above a predetermined value, it outputs an L signal, and when it is less than a predetermined value, it outputs an H signal. Output to 10. A resistor 59 is provided between the input terminal of the inverter 57 and the power supply terminal A to stabilize the operation of the inverter 57. 60 is a defrosting circuit. A first positive contact 61 of a timer device, which will be described later, and a diode 6 are connected between power terminals G and H.
2. A series circuit of resistors 63, 64 and a light emitting diode 58 is connected, and a series circuit of a second positive contact 65 of the contact timer device and a defrosting heater 66 is provided in parallel with the series circuit. Capacitor 6 in parallel with the series circuit with diode 58
7 is provided. Both contacts 61 and 65 are closed by the defrost output of the defrost timer device 68.

The operation of one embodiment of the temperature display method will be described below with reference to the figures.

When the temperature of the temperature sensor 1 decreases due to a decrease in the internal temperature during cooling operation in a refrigeration cycle of a refrigerator or the like, the impedance of the temperature sensor 1 increases.

Accordingly, the (-) side input of the operational amplifier 2 decreases and the output voltage increases. Operational amplifier 4 sent from operational amplifier 2 via adjustment resistor 5 and resistor 6
The output voltage of the operational amplifier 4 decreases due to an increase in the (-) input of the operational amplifier 4. Movable contact piece 23 of changeover switch 21
When the fixed contact 22A is closed, the output of the operational amplifier 4 is applied to the input terminal 25 of the A/D converter 8, and the analog signal is converted into a digital signal. The output of the A/D converter 8 is converted by decoder drivers 9 and 10 with latches into an output that can be displayed numerically on the display section 11, and is sent to the display section 11, where the decreased internal temperature is displayed numerically. When the movable contact piece 23 of the changeover switch 21 is closed to the fixed contact 22B, the display section 11 displays the set temperature inside the refrigerator.
Further, the output of the operational amplifier 4 becomes the (+) side input of the operational amplifier 27 via the resistor 28, and the voltage divided by the adjustment resistor 19 and the resistor 20 becomes the (-) side input. Here, when the output voltage of the operational amplifier 4 decreases as the temperature inside the refrigerator decreases, the change in the output voltage becomes a change in the (+) side input of the operational amplifier 27 via the resistor 28. When the output voltage of the operational amplifier 4 further decreases to the voltage set by the adjustment resistor 19 and the resistor 20, the output voltage of the operational amplifier 27 decreases due to the positive feedback operation of the resistor 29, and the NPN transistor 32 becomes non-conductive. , the movable contact piece 36 of the electromagnetic switch 33 opens, and the refrigeration system 37 stops operating.

On the other hand, during cooling operation, the defrost output of the defrost timer device 68 closes the tangent points 61 and 65.
When the defrosting heater is energized and defrosting operation is started, a voltage is simultaneously applied to the light emitting diode 58 of the photocoupler 51 and it lights up, the phototransistor 52 becomes conductive, and the (+) of the operational amplifier 39 is turned on.
The side input becomes an H signal, and the operational amplifier 39 outputs the H signal to the lighting section 14 of the display section 11.
is lit to notify defrost. At this time, the buffer 38 prevents the output of the phototransistor 52 from affecting the operational amplifiers 4, 27, A/D converter 8, etc. Further, the (-) side input of the operational amplifier 39 is adjusted to the defrost alarm return voltage, that is, the defrost alarm return temperature, by the adjustment resistor 43.
When the photo transistor 52 is conductive, (+)
It is assumed that the side input is sufficiently larger than the (-) side input.
At the same time as the phototransistor 52 becomes conductive, a signal of a predetermined value or more is applied to the inverter 57, and the output of the inverter 57 becomes an L signal, and the L signal is applied to the terminals 12 and 13 of the latch decoder driver 9 and 10. 9,1
0 stops the output and the temperature display on the display section 11 disappears. When the temperature inside the refrigerator rises during the defrosting operation period and becomes higher than the defrost alarm return temperature determined by the adjustment resistor 43, the time-up operation of the defrost timer device 66 causes the positive junction 61,
65 is opened and the defrosting operation is completed, the light emitting diode 58 goes out, the phototransistor 52 becomes non-conductive, and the input of the inverter 57 becomes an L signal and the output becomes an H signal. Therefore, the H signal is applied to the terminals 12 and 13 of the decoder drivers 9 and 10 with latches, the decoder drivers 9 and 10 with latches output, and the display section 11 displays the temperature. At the same time, the H signal is no longer sent from the phototransistor 52 to the (+) side input of the operational amplifier 39, but since the temperature inside the refrigerator is higher than the defrost alarm return temperature, the (-) side input of the operational amplifier is determined by the adjustment resistor 43. Therefore, since the (+) side input of the operational amplifier 39 sent from the operational amplifier 4 through the buffer 38 is large, the operational amplifier 39 outputs an H signal, and after the defrost operation is completed, the temperature inside the refrigerator drops to the defrost alarm return temperature. Until then, the display section 11 displays the temperature and lights up the lighting section 14 to continue to notify defrost. still,
The photocoupler 51 turns on and the H signal is sent from the phototransistor 52 to the operational amplifier 3 through the resistor 42.
9, while the operational amplifier 39 is outputting the L signal, the input side of the non-inverter 40 is drawn to the L signal through the diode 46, but the output of the operational amplifier 39 is is H
At the same time as the signal, the input of the non-inverter 40 passes from the emitter of the phototransistor 52 through the diode 49 and the resistor 50 to become an H signal, so its output also becomes an H signal and remains at the H signal through the resistor 55. When the temperature inside the refrigerator falls below the defrost alarm return level due to operation of the cooling system, the (+) side input of the operational amplifier 39 becomes below the (-) side input, the operational amplifier 39 outputs an L signal, and the lighting section 14 turns off. , the defrost notification ends. At this time, the input side of the non-inverter 40 is drawn by the L signal output from the operational amplifier 39 via the diode 46, and becomes an L signal, and the output side also becomes an L signal. On the other hand, at the end of the defrosting operation, if the temperature inside the refrigerator is below the defrost alarm return temperature, the display section displays the temperature inside the refrigerator in the same way as described above, and at the same time the lighting section 14
will turn off and the defrost notification will end. At this time, the input side and the output side of the non-inverter 40 become L signals, similar to the above. On the other hand, during cooling operation, sensor 1
Since the detected temperature is low, its output voltage is also low, so the output voltage of the buffer 38 is low, the + input voltage of the operational amplifier 39 is lower than the - input voltage, and the output becomes L. Therefore, the input voltage of the non-inverter 40 is pulled to L by the diode 46, and the output becomes L. Furthermore, a diode 53 and a resistor 54
The voltage after passing through the resistor 41 at the output of the buffer 38, that is, the input voltage of the operational amplifier 39 is L.
For example, due to a failure of the compressor or evaporator fan motor, the temperature inside the refrigerator increases, and the temperature detected by the sensor 1 increases, causing the buffer 38 to rise.
Even if the output voltage of the operational amplifier 39 increases, the input voltage of the operational amplifier 39 does not increase, and the display section 11 does not issue a defrost notification but only displays a high temperature display. Therefore, it is possible to accurately determine whether a high temperature display continues when the cooling operation is restarted after the defrosting operation is completed, or a high temperature display due to an abnormality, such as a failure in the refrigeration cycle of the compressor or a failure in the evaporator fan motor. Furthermore, when the cooling operation is restarted after the defrosting operation is finished, the timer will operate.
Compared to a time-controlled defrost notification means that continues the defrost notification for a predetermined period of time, the present invention is a temperature-controlled defrost notification unit that detects the internal temperature and ends the defrost notification. If the temperature drops below the temperature and the high temperature display is performed again within the predetermined time, it cannot be determined that the high temperature display is due to a malfunction of the compressor, etc., because in the case of time control, a defrost alarm is issued at the same time. In the case of temperature control, it can be clearly determined. Furthermore, when the cooling load is large and it takes longer than the predetermined time for the temperature inside the refrigerator to drop below the predetermined temperature, only the high temperature display is performed without a defrost notification, so that it is not determined that there is a malfunction in the compressor, etc. .

When the power is turned on, the input side of the non-inverter 40 is connected to the operational amplifier 39 (+ ) side input becomes an L signal, and its output becomes an L signal. That is, since the output of the buffer 38 connected to the temperature sensor 1 is becoming the power source for the non-inverter 40, when the temperature detected by the sensor 1 is high, the output voltage of the buffer 38 becomes high and Without it, the input voltage of the non-inverter 40 may become H when the power is turned on. In case of H, non-inverter 40
is ON and the output becomes H, so operational amplifier 3
Since the output of 9 also becomes H and the defrost alarm is turned on, a problem occurs when the power is turned on. Therefore, the resistor 50 and capacitor 56 are used to suppress the increase in the input voltage of the non-inverter 40. Therefore, the notification unit 14 does not light up and defrost notification is not performed.

In the above embodiment, the lighting section 14 provided in the display section 11 was used as a notification means to display the defrosting of the cooler during defrosting and to operate continuously for a predetermined period of time when the cooling operation is resumed after defrosting. A similar effect can be obtained by using other notification means such as a buzzer.

As described above, the present invention includes a display means for displaying the internal temperature of a refrigerator or the like and a notification means for informing that the cooler is being defrosted, and operates the defrosting time notification means and disables the display means. Some devices operate the display means when the cooling operation is restarted after defrosting and continue to operate the notification means until the temperature inside the refrigerator falls to a predetermined temperature after defrosting. High temperature display on the display means and when there is an abnormality in the refrigerator, etc. For example, the compressor,
It is possible to more accurately determine when a high temperature display is caused by a failure of the evaporator fan motor, etc., compared to a time-controlled defrost notification means.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram of an internal temperature detection and temperature display circuit and a temperature control switch circuit, and FIG. 2 is an electric circuit diagram of a defrost notification circuit and a defrost circuit. In the figure, 1 is a temperature sensor, 2, 4, 27, and 39 are operational amplifiers, 8 is an A/D converter, 9 and 10 are decoder drivers with latch, 11 is a display unit, and 32 is a
NPN type transistor, 33 is an electromagnetic switch, 37
38 is a buffer, 40 is a non-inverter, 51 is a photocoupler, 57 is an inverter, 60 is a defrosting circuit, and 68 is a defrosting timer device.

Claims (1)

[Claims] 1 An operational amplifier that amplifies the analog signal from the temperature sensor that detects the temperature inside the refrigerator, an A/D converter that converts the amplified analog signal to a digital signal, and a decoder driver with a latch that converts the digital signal to a code signal. and a display section comprising a notification means for notifying defrosting of the evaporator and a display means for displaying the temperature inside the refrigerator based on the code signal, a defrosting timer device for outputting a defrosting signal, a defrosting heater, etc. means for activating the notification means in response to the defrost signal; and an operating circuit for reducing the output from the decoder driver with a latch to the display unit to stop the display on the display unit when the defrost signal is output; an inverter that restores the display of the display means when the output is not output, and a continuation means that continues the operation of the notification means until the internal temperature of the refrigerator falls to a predetermined value after defrosting is completed, and operates the defrosting time notification means. A temperature display method characterized by disabling the display means, activating the display means when cooling operation resumes after defrosting, and continuously operating the notification means until the internal temperature of the refrigerator falls to a predetermined temperature.