JPS6115349B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature display device that displays temperature values using a plurality of light emitting elements, including lighting of the light emitting elements,
The purpose is to display a certain temperature range by turning off or blinking, and also to display temperatures above and below the temperature range, and to also display whether the temperature above the temperature range is normal or abnormal.

In general, alcohol, mercury, or pointer thermometers are used as thermometers for refrigeration equipment such as refrigerators. However, these thermometers simply display the high and low temperature values, and the temperature values do not indicate whether the temperature value is in the cooling operation of the refrigeration cycle, the thermocycle operation in which the compressor is stopped intermittently, or the defrosting operation. It was not possible to confirm whether the temperature value was displayed or whether the operating condition during each operation was normal.

The present invention has been made in view of these points, and embodiments thereof will be described below with reference to the drawings.

FIG. 1 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 , R ₂
is a protection resistor, D ₁ and D ₂ are Zener diodes that constitute the constant voltage circuit, and D ₃ is a diode.
Reference numeral 3 designates a temperature detection element such as a negative characteristic thermistor which constitutes a temperature detection bridge circuit together with fixed resistors R ₃ , R ₄ and R ₅ . 4 is an operational amplifier that amplifies the unbalanced voltage generated between the signal terminals a and b of the temperature detection bridge circuit. A resistor _R6 is connected between the output terminal and the one side 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 input terminal on the 1st side to the emitter of transistor Q ₅ , which will be described later, through the resistor R ₁₀ , and connects the input terminal on the 1st side 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 positive input terminal.
Connect a capacitor _C2 between the output terminal and one side input terminal
A resistor R ₈ constituting a charging/discharging circuit is also connected thereto, and 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 a light emitting diode 6 connected to a defrosting device
D and a photoelectric conversion element 6R connected to the output terminal of the operational amplifier 5, and is a photocoupler that is an element for displaying a temperature that is not in an abnormal state such as defrosting operation at a temperature above the displayed temperature range,
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 defrosting of the cooler is started and AC input is given, the light emitting diode 6D is turned on and the output resistance is low. Q ₁ and Q ₂ are PNPs that constitute a current mirror amplifier
The type transistors _Q5 to _Q13 are PNP type transistors whose bases are connected to the output terminal of the operational amplifier 4 via respective resistors _R19 to _R27 . D ₁₁ to D ₁₉ are light emitting elements (hereinafter referred to as light emitting diodes) that emit red light and are connected between the emitter and collector of each of the transistors Q ₅ to _{Q 13} ;
Turns the light off (OFF) when turned ON, lights up (ON) when turned OFF, and displays the temperature 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 it is connected to a PNP transistor Q ₄ provided as an on/off element.
Together with the NPN transistor Q ₃ , resistors R ₁₄ , R ₁₅ , R ₁₆ and diode D ₈ , it constitutes a circuit that indicates when the temperature is below the detection temperature. In addition, R ₁₁ , R ₁₂ , R ₁₃ , R ₁₇
is a resistor and _D9 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 sensing element 3 increases due to a decrease in ambient temperature, the output voltage of the operational amplifier 4 will drop, and when the base voltage becomes lower than the emitter voltage of each of the transistors _Q5 to _Q13 , the
When the ON condition is satisfied, the light emitting diodes D ₁₁ to _{D 19} are sequentially turned off depending on the degree of drop in the output voltage of the operational amplifier 4 until the ON condition for each transistor is satisfied. Therefore, as the impedance of the temperature measuring element 3 decreases, the light emitting diode displays a low temperature value.
Light-emitting diodes _D10 to _D11 , which display the high temperature value, are turned on in sequence, and conversely, light-emitting diodes _D11 to _D19 are turned off in sequence as the impedance of the temperature measuring element 3 increases, and the temperature is within the temperature measurement range, that is, during cooling operation. Display temperature.

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. The emitter voltage of transistor Q ₅ is determined by comparing the input on the other side, which is connected to the emitter of transistor Q 5 and serves as the reference voltage of operational amplifier 5, and the one side input of operational amplifier ₅ , which is connected to the output terminal of 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 _C2 gradually drops through the resistor _R8 due to the time constant of the capacitor/resistance, and since the one side input of the operational amplifier 5 has a constant voltage drop than the positive side input, the ON condition of the operational amplifier 5 is satisfied and its output rises to the supply voltage and is now connected to the capacitor through resistor _R8 .
_C2 is charged to satisfy the OFF condition for the operational amplifier 5, and this charging/discharging operation is repeated. When operational amplifier 5 is ON and its output voltage is zero,
Transistor through diode D ₇ and resistor R ₉
The base voltage of Q ₅ ~ Q ₁₃ drops and the transistor Q ₅
- Q ₁₃ are turned on sequentially, and conversely, light-emitting diodes D ₁₁ - _{D 19} are sequentially turned off. How many light emitting diodes _D11 to _D19 are turned off is determined by the resistor.
It is determined by the size of _R9 , and by making it large, only one light emitting diode _D11 blinks, and by making it small, light emitting diodes _D11 to _D19 can be made to blink at the same time. 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 diodes D ₁₁ to D ₁₉
The entire display flashes to indicate the temperature during defrosting operation. Also, when the light emitting diodes D ₁₁ to _{D 19} flash to indicate a high temperature due to defrosting operation, for example, if the defrosting device malfunctions and the photo coupler 6
When the AC input is no longer applied to the photocoupler 6, the output resistance of the photocoupler 6 increases, and the
D ₁₂ to _{D 19} switch from flashing to lighting, and only light emitting diode D ₁₁ flashes continuously, indicating an abnormal temperature outside the temperature measurement range. This change in display causes a high temperature display during defrosting. It can be determined whether this is due to normal defrosting or a malfunction of the defrosting device.

Next, another embodiment of the present invention will be explained with reference to FIG. FIG. 2 shows a circuit for displaying a temperature below the temperature measurement range. For example, in the case of a refrigeration cycle, the temperature display will be explained in the case where the thermostat for controlling the temperature inside the refrigerator, which controls the operation of the compressor, fails. When the ambient temperature drops abnormally and the impedance of the temperature sensing element 3 becomes high, and the output voltage of the operational amplifier 4 drops, the positive input of the third operational amplifier 7 becomes the anode of the light emitting diode _D19 and the emitter of the transistor _Q13. Since the output voltage of the operational amplifier 4, which is the input on one side of the operational amplifier 7, becomes about 0.6V lower than the emitter voltage of the transistor _Q13 due to the diode _D21 , the transistor _Q13 starts to turn on and emits light. The diode _D19 begins to disappear, and the ON condition for the operational amplifier 7, ie, the input voltage on the 1st side>the input voltage on the 1st side, is established, positive feedback is applied by the resistor _R29 , and the operational amplifier 7 is turned ON. Then, the output of operational amplifier 7 rises to the power supply voltage, and the resistor
The capacitor _C3 is charged through _R14 to increase the one-side input voltage, and the OFF condition, that is, one-side input voltage≧the tenth-side input voltage, is established, and the operational amplifier 7 is turned off and its output becomes zero. Then, the capacitor C ₃ starts discharging through the resistor R ₁₄ , and the input voltage on one side gradually drops, turning the operational amplifier 7 ON, and this charging and discharging causes the ON and OFF operations to be repeated. When the output of operational amplifier 7 is ON,
Transistor through resistor R ₃₀ , diode D ₂₁
The base voltage of Q ₁₃ increases and transistor Q ₁₃
When it is OFF, the light emitting diode _D19 lights up, and in the opposite case it goes out. That is, the blinking of the light emitting diode _D19 indicates that the temperature is below 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 displays the light emitting diode at temperatures above the temperature measurement range, which is different from that during thermocycle operation.
It is possible to display temperature values during defrosting operation that are different from those caused by failures of each device by flashing D ₁₁ to _{D 19} , and it is possible to check whether the temperature values in each operating state are normal or abnormal. This makes it possible to take appropriate measures against abnormal conditions.

Since the present invention is configured as described above,
It is easy to check the temperature value in each operating state of equipment that requires a temperature display device by displaying the lighting, turning off, and blinking of multiple light emitting elements, and the difference in each display makes it easy to check whether the temperature value is normal or abnormal. It can also be easily confirmed that

[Brief explanation of the drawing]

1 and 2 are circuit diagrams showing mutually different embodiments of the temperature display device of the present invention. 3... Temperature measuring element, 4, 5, 6... operational amplifier,
_Q5 to _Q13 ...Transistors, _D11 to _D20 ...Light emitting elements.

Claims (1)

[Claims] 1 a temperature measuring element, a first operational amplifier whose output changes based on the voltage between the terminals of the temperature measuring element, and the first operational amplifier.
a plurality of light emitting elements that display a predetermined temperature range by sequentially turning on and off based on the output of the operational amplifier; and a first charging/discharging circuit that operates when the temperature measuring element detects a temperature higher than the temperature range. a second operational amplifier that blinks any element among the plurality of light emitting elements based on the temperature range; and a second operational amplifier that operates based on the output of the first operational amplifier to display a low temperature when the temperature measuring element detects a temperature lower than the temperature range. one of an on-off element that lights up a light emitting element for use with the light emitting element and a third operational amplifier that blinks any element of the plurality of light emitting elements based on the operation of the second charging/discharging circuit; and the second operational amplifier. output based on a signal from the defrosting device or the like when the temperature measuring element connected between the temperature sensing element connected between the temperature sensing element and the plurality of light emitting elements detects a temperature higher than the temperature range that is not in an abnormal state such as defrosting operation. A temperature device characterized by comprising an element whose resistance changes to cause any one of the plurality of light emitting elements to blink in a display state different from a display state at a temperature higher or lower than the temperature range. Display device.