JPH0228781B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a temperature display device for refrigeration equipment, which is used in refrigeration equipment such as a freezer, and displays temperature using a plurality of light emitting elements.

(b) Prior art For example, Japanese Utility Model Application Publication No. 52-43767 discloses a timer switch that operates during the defrost period and a defrost A temperature alarm device for a cooling storage is shown in which the alarm operation is canceled from the start of defrosting to a predetermined time after the end of defrosting by means of a timer switch that operates for a predetermined period after the end of defrosting.

For example, Japanese Utility Model Application Publication No. 52-63771 includes a meter that not only indicates whether the refrigerated room temperature is the preservation temperature, caution temperature, or dangerous temperature, but also indicates that the cooling device is being defrosted. A temperature display device for a cooling device is shown.

(C) Problems to be Solved by the Invention In the above-mentioned Japanese Utility Model Application Publication No. 52-43767, when the above-mentioned alarm operation at the time of defrosting is canceled, for example, the defrosting heater or the like malfunctions and the defrosting is not actually performed. The problem is that when the refrigerator stops, the alarm continues to be canceled even though the temperature inside the refrigerator has risen due to defrosting, and the user is not alerted to the rise in the temperature inside the refrigerator. It was occurring.

Further, in the above-mentioned Japanese Utility Model Publication No. 52-63771, when the meter indicates that defrosting is in progress while the cooling device is defrosting, for example, if the defrosting device malfunctions, the meter indicates that the defrosting If the display continues to indicate that the refrigerator is in the refrigerator and does not switch to the display of the interior temperature, the user will only know that defrosting is in progress, but the interior temperature will be at the caution or dangerous temperature. This has caused problems such as delays in responding to defrosting device failures or increases in internal temperature. The present invention aims to solve the above problems.

(d) Means for Solving the Problems In order to solve the above problems, the present invention includes a temperature measuring element that detects the internal temperature of the refrigeration equipment, and an output based on the voltage between the terminals of the temperature measuring element. a first circuit;
a plurality of light emitting elements that display a predetermined temperature range by sequentially turning on and off based on the output of the first circuit; and a first charging/discharging circuit when the temperature measuring element detects a temperature higher than the temperature range. a second circuit that blinks any one of the plurality of light emitting elements based on the operation of the second circuit; When a temperature higher than the temperature range is detected, any light emitting element among the plurality of light emitting elements is activated to display a temperature within the temperature range and a temperature display higher than the temperature range based on a signal from the defrosting device. The present invention provides a temperature display device for refrigeration equipment, which is equipped with a circuit that causes the temperature to blink in a manner different from that shown in the figure.

(E) Function A predetermined temperature range is displayed by turning on and off a plurality of light emitting elements, and when the temperature measuring element detects a temperature higher than the temperature range, the operation is based on the operation of the first charging/discharging circuit. A change in the output side potential of the second operational amplifier causes any element among the plurality of light emitting elements to blink, and further, during defrosting operation, the operation of the element based on a signal from the defrosting device causes the plurality of light emitting elements to blink. The element is displayed in a display state that is different from the display state when the temperature is higher than the above-mentioned temperature range, indicating that the defrosting operation is in progress. When disappears,
The plurality of light emitting elements switch to display an abnormal temperature higher than the temperature range.

(F) Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

The drawing shows a temperature display device of the present invention, in which 1 is a power transformer whose primary winding is connected to an AC power source, 2
is a diode bridge rectifier circuit connected to the secondary winding of the transformer, C ₁ is a smoothing capacitor connected between the output terminals of the rectifier circuit, R ₁ and R ₂ are protective resistors, and D ₁ and D ₂ is a Zener diode that constitutes a constant voltage circuit, and D ₃ is a diode. 3
is a temperature detection element such as a negative characteristic thermistor that constitutes a temperature detection bridge circuit together with fixed resistors R ₃ , R ₄ , and R ₅ . Reference numeral 4 denotes an operational amplifier for amplifying the unbalanced voltage generated between signal terminals a and b of the temperature detection bridge circuit, the positive input terminal of which is connected to signal terminal a, the negative input terminal connected to signal terminal b, and the output A resistor _R6 is connected between the terminal and the negative input terminal, and a diode _D5 is interposed between the output terminal and the bases of transistors _Q5 to _Q13 , which will be described later. 5
connects the + side input terminal to the emitter of transistor Q ₅ , which will be described later, via resistor R ₁₀ , and connects the one side input terminal to the resistor.
R ₇ is an operational amplifier connected to the output terminal of the operational amplifier 4 via a diode D ₆ , and a positive feedback resistor R ₁₈ is connected between the output terminal and the + side input terminal.
Connect a capacitor C ₂ between the output terminal and the negative input terminal.
Connect the resistor _R8 that forms the charge/discharge circuit with the
Further, a resistor R ₉ and a diode D ₇ are connected between the output terminal and the anode of the diode D ₅ .
6 is an element for displaying a temperature that is higher than the temperature range and is not in an abnormal state due to defrosting operation, such as a light emitting diode 6D connected to the defrosting device and a photoelectric conversion element 6R connected to the output terminal of the operational amplifier 5. With this photo coupler, when there is no AC input, the light emitting diode 6D is turned OFF and the output resistance of the photoelectric conversion element 6R is high, and when the cooler defrost is started and AC input is given, the light emitting diode 6D is turned ON. Output resistance is lower.
Q ₁ and Q ₂ are PNP transistors constituting a current mirror amplifier, and Q ₅ to _{Q 13} are PNP transistors whose bases are connected to the output terminal of the operational amplifier 4 via respective resistors R ₁₀ to _{R 27} . . D ₁₁ to _{D 19} are light emitting elements (hereinafter referred to as light emitting diodes) that emit red light, which are connected between the emitters and collectors of the transistors Q ₅ to Q _13. When the transistors are turned on, the light is turned off (OFF), and when the transistors are turned OFF, the light is turned on. (ON) to display temperatures within the displayable temperature range (hereinafter referred to as temperature measurement range). D ₂₀ is a light emitting element (hereinafter referred to as a light emitting diode) that emits green light, and includes a PNP transistor Q ₄ , an NPN transistor Q ₃ , a resistor R ₁₄ ,
Together with R ₁₅ , R ₁₆ and diode D ₈ , it forms a circuit that indicates when the temperature is below the detection temperature. Furthermore, R ₁₁ ,
R ₁₂ , R ₁₃ , and R ₁₇ are resistors, and D ₉ is a Zener diode.

Next, the operation of the temperature display device will be explained. First, to explain the temperature display within the temperature measurement range, for example, the temperature display during normal cooling operation in the case of a refrigeration cycle such as a refrigerator, when the impedance of the temperature measurement element 3 decreases due to a rise in ambient temperature,
The output voltage of the operational amplifier 4 increases. This output voltage is compared with the emitter voltage which is the reference voltage of the transistors _Q5 to _Q13 , and if the output voltage is equal to or higher than the reference voltage, each transistor _Q5 to _Q13
The base voltage becomes higher than the emitter voltage of , transistors Q ₅ to _{Q 13} turn OFF, and the light emitting diode
_D11 to _D19 are lit. i.e. each light emitting diode D ₁₁
~ Transistors Q ₅ connected in parallel with D _{19 ~}
Q ₁₃ lights up the light emitting diode by OFF,
When turned on, the light emitting diodes are turned off, and the light emitting diodes D ₁₁ to _{D 19} are lit continuously until the OFF conditions for the transistors Q ₅ to _{Q 13} are satisfied depending on the degree of rise in the output voltage of the operational amplifier 4. Conversely, if the impedance of the temperature measuring element 3 increases due to a decrease in the ambient temperature, the output voltage of the operational amplifier 4 will decrease,
When the base voltage becomes lower than the emitter voltage of each transistor _Q5 to _Q15 , the ON condition for each of the transistors is satisfied, and the light emitting diodes _D11 to _D19 turn ON to each transistor depending on the degree of drop in the output voltage of the operational amplifier 4. The lights are turned off one after another until the condition is met. Therefore, as the impedance of the temperature measuring element 3 decreases, the light emitting diode displays a low temperature value.
The light emitting diode _D11 , which displays the high temperature value, lights up sequentially from _D19 , and conversely, as the impedance of the temperature measuring element 3 increases, the light emitting diode _D11 lights up.
The lights go out one after another until D ₁₉ , and the temperature within the temperature measurement range, that is, during cooling operation, is displayed.

Also, a temperature display above the temperature measurement range, for example, a temperature display during a thermocycle operation, which temporarily stops the operation of the compressor in the refrigeration cycle and causes an increase in the temperature inside the refrigerator, will be explained. By comparing the + side input connected to the emitter of the transistor Q ₅ and serving as the reference voltage of the operational amplifier 5 and the − side input of the operational amplifier 5 connected to the output terminal of the operational amplifier 4, the emitter voltage of the transistor Q ₅ becomes the reference voltage of the operational amplifier 4. When the output voltage becomes equal to or lower than the base voltage of the transistor _Q5 , the operational amplifier 5 becomes a switch circuit with positive feedback, so there is no input difference, and the output becomes zero, resulting in an OFF condition. Then, the capacitor
The voltage of C ₂ gradually drops through the resistor R ₈ than the time constant of the capacitor/resistance, and since the negative input of operational amplifier 5 has a constant voltage drop than the positive input, the ON condition for operational amplifier 5 is satisfied and its output rises to the supply voltage and is now connected to capacitor C ₂ through resistor R ₈
is charged to satisfy the OFF condition for operational amplifier 5,
This charging/discharging operation will be repeated. When the operational amplifier 5 is ON and its output voltage is zero, the transistors Q ₅ ~ through the diode D ₇ and the resistor R ₉
The base voltage of _Q13 drops and transistor _Q5 ~
The light-emitting diodes _D11 to D19 are sequentially turned on, and the light-emitting diodes _D11 to _D19 are sequentially turned off.
The size of the resistor _R9 determines how many light-emitting diodes _D11 to _D19 are turned off.By increasing the resistor R9, only one light-emitting diode _D11 blinks, and by decreasing the resistor R9, the light-emitting diodes _D11 to _D19 also blink at the same time. can be done. Therefore, by increasing the resistance R ₉ and causing one light emitting diode D ₁₁ to blink, it is indicated that the thermocycle operation is being performed at a temperature that is above the temperature measurement range. In this case, since the emitter of the transistor _Q5 is used as the reference voltage, the blinking operation does not occur during cooling operation, that is, when the temperature returns to within the temperature measurement range.

Furthermore, the lowest temperature display within the temperature measurement range, for example, in the case of a refrigeration cycle, a temperature display that indicates that the inside of the refrigerator is too cold just before the thermostat for controlling the temperature inside the refrigerator is turned off will be explained. When the output voltage of the operational amplifier 4 becomes lower than the emitter voltage of the transistor _Q13 , the transistor _Q13 is turned on and the light emitting diode _D19 is turned off. Then, with a delay of the voltage of diode _D8 (approximately 0.6V), the base voltage of transistor _Q4 drops, and together with that transistor, transistor _Q3
turns ON, lighting up the light emitting diode _D20 . That is, when the red light emitting diode _D19 starts to go out, the green light emitting diode _D20 starts to light up, indicating that the inside of the refrigerator is too cold.

In addition, if the temperature is above the temperature measurement range and is different from the temperature display of the thermocycle operation, for example, in the case of a refrigeration cycle, the temperature inside the refrigerator may be changed once or several times a day to defrost the cooler. The temperature display during defrosting operation, which causes an increase in temperature, will be explained. Now, when the resistance R ₉ is high and defrosting is started and there is AC input, the output resistance of the photocoupler 6 becomes small, and when the display voltage is exceeded, the light emitting diode D ₁₁ ~
The entire D ₁₉ flashes to indicate the temperature during defrosting operation. Also, light emitting diode D ₁₁ ~
When D ₁₉ is blinking and a high temperature is displayed due to defrosting operation, for example, if the defrosting device breaks down and AC input is no longer given to the photocoupler 6, the output resistance of the photocoupler 6 increases and the light emitting diode D ₁₁ to _{D 19} switch from blinking to lighting, and only the light emitting diode D ₁₁ blinks to display an abnormal temperature outside the temperature measurement range.

As described above, according to the present invention, when the temperature display device is used in a refrigeration cycle of a refrigerator or the like, any light emitting diode among the light emitting diodes D ₁₁ to _{D 20} is turned on or off within the temperature measurement range, and the temperature display device is turned on or off during cooling operation. It displays the temperature value, and when the temperature is above the temperature measurement range, the light emitting diode D ₁₁ blinks to indicate an abnormal temperature value due to compressor failure during thermocycle operation, and when the temperature is below the temperature detection range, the light emitting diode D ₁₉ blinks. Displays the temperature value of supercooling during cooling operation, and also lights up the light emitting diodes _D11 to _D19 all on and off when the temperature is outside the temperature measurement range, which is different from that during thermocycle operation. It is possible to display the temperature value during defrosting operation, and in addition, if the defrosting device malfunctions during defrosting operation, the photocoupler 6 can be disconnected from the defrosting device.
When AC input stops, the output resistance of photocoupler 6 becomes smaller, light emitting diodes D ₁₂ to _{D 19} light up, and light emitting diode D ₁₁ blinks, indicating an abnormal temperature above the temperature measurement range and notifying the administrator. This makes it easy to confirm whether the temperature value in each operating state is normal or abnormal, and appropriate processing can be performed for abnormal states.

(g) Effects of the invention Since the present invention is configured as described above,
In a temperature display device for a low-temperature refrigerator that performs a defrosting operation of a cooler, confirmation of the temperature value in each operating state of the device is facilitated by displaying lighting, turning off, and blinking of a plurality of light emitting elements, and each of the above Due to the difference in the display, if the defrost device malfunctions during defrosting operation, the output resistance of the photo coupler will increase and the light emitting diode that makes up the photo coupler will turn off, so the defrost device will In addition to accurately determining that there is a failure in the defrosting device, even when the output from the defrosting device is stopped, the failure of the device connected between the second operational amplifier and the plurality of light emitting devices and inputting the output is detected. Upon operation, the plurality of light emitting elements switch to display an abnormal temperature, which notifies the administrator of the low temperature refrigerator that the temperature inside the refrigerator is abnormal, and allows appropriate processing to be performed in response to the abnormal condition during defrosting operation. can.

[Brief explanation of drawings]

The drawing is a circuit diagram showing an embodiment of a temperature display device for a low-temperature refrigerator according to the present invention. 3...Temperature measuring element, 4, 5...First and second operational amplifiers, 6...Element for detecting a signal from the defrosting device (photocoupler), _D11 to _D20 ...Light emitting elements.

Claims (1)

[Claims] 1 A temperature measuring element that detects the internal temperature of the refrigeration equipment,
A first output based on the voltage between the terminals of the temperature measuring element.
a plurality of light emitting elements that display a predetermined temperature range by sequentially turning on and off based on the output of the first circuit; a second circuit that blinks any one of the plurality of light emitting elements based on the operation of the charging/discharging circuit; a photoelectric conversion element connected to the output terminals of both the first and second circuits; and a defrosting device. and a light emitting diode connected to the photocoupler, the photocoupler is operated based on a signal from the defrosting device during the defrosting operation, and when the temperature measuring element detects a temperature higher than the temperature range during the defrosting operation. a circuit that causes any light emitting element among the plurality of light emitting elements to blink in a manner different from a temperature display for a temperature within the temperature range and a temperature display for a temperature higher than the temperature range, based on a signal from the defrosting device; A temperature display device for refrigeration equipment, characterized by comprising: