JPS6324234B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for monitoring the temperature of a refrigerator.
The present invention relates to a temperature alarm device for a refrigerator that is configured to issue an external alarm for both high and low temperatures without causing false alarms.

Conventionally, temperature alarms used in refrigerators have often been constructed of mechanical relays, time-limited relays, liquid ring thermostats, etc., or electronic means. However, the former was constructed as shown in FIG.

That is, L1 and L2 in Fig. 1 are
This is a power line to which AC100V or 200V voltage is applied. Between the power lines L1 and L2, there is a contact 21 of a liquid ring thermostat and a relay 2.
2 is connected, and the normally open contact 22a of this relay 22 is connected to the series circuit of the time-limiting relay 23.

In addition, between the power lines L1 and L2, a time-limited contact 23a of a time-limited relay 23 and a buzzer 2 for abnormality alarm are provided.
A series circuit with 4 is connected.

Next, the operation of the conventional temperature alarm shown in FIG. 1 will be explained. When the contact 21 of the liquid ring thermostat closes due to the detection of the high temperature inside the refrigerator, the relay 22 is energized and the normally open contact 22a is closed.
is closed. As a result, the time-limited relay 23 is started, and when the liquid ring thermostat 1 continues to detect the temperature inside the high-temperature refrigerator for a certain period of time or more, the time-limited relay 23 is activated, its time-limited contact 3a is closed, and the buzzer 24 is activated. The system is designed to alert the outside world of abnormalities.

However, since such temperature alarms use liquid-sealed thermostats, the distance between the temperature sensing part of the thermostat is limited, and it must be housed in the same area as the electrical components such as relays. This configuration has the drawback that the installation location of the alarm body is limited, and furthermore, the thermostat contact point 2
1. The relay 22, the time-limited relay 23, etc. are expensive, and the alarm main body is also large in size.

On the other hand, in the case of the latter, the disadvantage of the former, which is that the shape of the alarm body becomes large, is solved because it is configured by electronic means, but in terms of functionality, when it is determined that the internal temperature has risen, In many cases, the function is to alert the outside as an abnormality after a certain period of time, or the structure is such that abnormalities in the refrigerator (freezer), cooler, and condensing device are captured and controlled by the alarm. It was the same as a temperature alarm consisting of mechanical parts.

In addition, some conventional temperature alarms have the function of not only warning when the temperature inside the refrigerator rises but also when the temperature inside the refrigerator drops abnormally. , the function immediately issues an external alarm and simultaneously stops the refrigeration system, which solves problems such as internal contents freezing, but malfunctions often occur because there is no time-limited operation when the temperature drops abnormally. Since the refrigeration equipment was stopped, the temperature inside the refrigerator would rise abnormally.

This invention has been made in consideration of the above points, and uses electronic means to set a time limit until alarm or stop when a high internal temperature is detected and a low internal temperature is detected using a single counter-type timer. The purpose of the present invention is to provide a temperature alarm device for a refrigerator that can be automatically switched.

Embodiments of the temperature alarm device for a refrigerator according to the present invention will be described below with reference to the drawings. FIG. 2 is a circuit diagram showing the configuration of one embodiment. Reference numeral 1 in FIG. 2 is a power supply, which is composed of a transformer 1a, a rectifier circuit 1b, and a smoothing capacitor 1c. In the primary winding of transformer 1a,
AC 100V or 200V is applied, and the input end of a rectifier circuit 1b is connected to the secondary winding of this transformer 1a. The DC voltage rectified by the rectifier circuit 1b is smoothed by the capacitor 1c.

Both ends of the output side of the rectifier circuit 1b (that is, both ends of the capacitor 1c) are connected to lines L11 and L, respectively.
12. A positive voltage is applied to the line L11, and a negative voltage is applied to the line L12.

A temperature detection bridge component 2 is connected between the lines L11 and L12. The temperature detection bridge component 2 is usually composed of a thermistor, a semiconductor sensor, a platinum resistor, etc., and a resistor having a known resistance value and a bridge.

Further, a high temperature detection temperature setting section 5 is connected between the lines L11 and L12. The output of the high temperature detection temperature setting section 5 and the output of the temperature detection bridge component 2 are input to a high temperature detection comparator 3. The output of this comparator 3 is output to a display 7 that indicates high temperature detection.

This indicator 7, together with the resistor R1, is connected to the line L1
1 and L12, and the output of comparator 7 is connected to terminal 16 of timer element 9 through diode D1.

Further, a low temperature detection temperature setting section 6 is connected between the lines L11 and L12. The output of this low temperature detection temperature setting section 6 and the output of the temperature detection bridge component 2 are inputted via a resistor 17 to a comparator 4 for low temperature detection.

The resistor 17 is a high resistor for preventing the temperature sensing bridge component 2 from becoming unbalanced due to positive feedback when detecting a low temperature. The output of the comparator 4 is then displayed on a display 8 that indicates low temperature detection.
It is now being supplied to This comparator 8 is connected in series with the resistor R2 to the lines L11 and L1.
It is connected between the two. The indicators 7 and 8 are each composed of a light emitting diode or the like.

The output of comparator 4 is also connected to terminal 16 of timer element 9 through diode D2. Comparator 4
Similar to the comparator 3, when detecting an abnormal temperature state, it is configured to output an output to the timer element 9 through diodes D2 and D1, and the timer element 9 starts timer counting.

Further, the output of the comparator 4 is also output to a switch circuit 15. The switch circuit 15 is mainly composed of a transistor Q1, the output of the comparator 4 is supplied to its base, the emitter is connected to the line L12, and the collector is connected to the timer element 9.
is connected to terminal 14 of.

This timer element 9 is a counting timer element equipped with a CR oscillation circuit 10 having a resistor R3 and a capacitor C, and when the oscillation frequency determined by the CR oscillation circuit 10 is counted by a predetermined value, the timer is up and the output terminal 11 is output. An output signal 12 is output to an alarm circuit 13. This alarm circuit 13 generates an alarm to the outside when an abnormal condition continues for a certain period of time.

Further, the timer element 9 is provided with a terminal 14 for changing the frequency division ratio of the counter described above, and the time limit interval for multiplying the predetermined value to be counted by 1 to 600 times can be changed in several stages (usually 2 to 4 stages). The value of the terminal 14 is determined depending on the stage, but in this embodiment, the terminal 14 is one terminal and the frequency division ratio is 1/10, and the terminal 14 is in an open state or a high signal. It shall be 1/10. For this reason, the terminal 14 has a switch circuit 15 for controlling the terminal signal.

In addition, the timer element 9 is provided with a terminal 16 that can control, stop, and reset the oscillation and counting described above, and when a low signal is input to this terminal 16, In this case, the timer element 9 is stopped.

Next, the operation of the refrigerator temperature alarm device of the present invention configured as described above will be explained. The comparator 3 for high temperature detection detects an abnormality and sends a high signal to the terminal 16 of the timer element 9 through the diode D1.
When the signal is output to , it is also output to the display 7 for high temperature detection, and this display 7 lights up.

At the same time, the timer element 9 starts operating,
The count starts, and after a time limit determined by the CR oscillation circuit 10, the count is increased, and the output signal 12 is output from the output terminal 11 as a high signal to alert the outside of an abnormality.

In this way, when a high signal is output from the comparator 3 for detecting a high temperature, a high signal is not output from the comparator 4 for detecting a low temperature, the switch circuit 15 is in an open state, and the frequency division Terminal 1 that determines the ratio
4 is in the open state, the timer count is executed to a predetermined value, and the timer is up, but normally high temperature detection is performed from 10 to It is often set between 180 minutes.

In other words, the comparator 8 for high temperature detection detects an abnormality within 10 to 180 minutes after detecting the abnormality, and alerts the outside of the abnormality.The time adjustment is made by varying the resistance value R that constitutes the above-mentioned CR oscillation circuit 10. Normally, it is set as follows.

Similarly, when the low temperature detection comparator 4 detects an abnormal temperature drop in the refrigerator and outputs a high signal, the low temperature detection indicator 8 lights up, and at the same time the switch circuit 15 is closed and the frequency division The terminal 14 is connected to the ground, that is, it becomes a low signal state, the frequency division ratio is 1/10, and the output signal 1 is output from the output terminal 11.
The time during which signal 2 is output as a high signal is 1/10, and is controlled from 1 to 18 minutes.

This time limit of 1 to 18 minutes will not cause fatal damage to the internal contents even if the time limit is set incorrectly.

In the above embodiment, the frequency division ratio was only switched to 1/10, but when the timer is configured with a normal timer element 9 or a counter IC, the division ratio is switched to 4.
It is possible to switch between stages to about 8 stages, and depending on the type of contents inside the refrigerator, it is possible to change the time limit to a greater degree than can be obtained by changing the capacitor C or resistor R of the CR oscillation circuit. .

In addition, not only the type of contents inside the refrigerator, but also the degree of rise or fall of the temperature inside the refrigerator can be determined in advance by measuring the time with another timer element or counter and switching to a predetermined frequency division ratio. If a problem occurs with the time limit for avoiding false alarms or normal temperature rise conditions, the time limit can be automatically shortened or expanded to suppress the problem from occurring.

As described above, according to the temperature alarm device for a refrigerator of the present invention, when an abnormality in the temperature inside the refrigerator is notified to the outside, the high temperature abnormality side detection input and the low temperature abnormality side detection input are connected to one timer element. By inputting to the same input terminal and automatically switching the counter division ratio for counting by the timer element depending on whether a high temperature is detected or a low temperature is detected, the time limit is adjusted. The occurrence of false alarms can be prevented, the circuit can be made smaller and lighter, and the configuration cost can also be lowered.

Further, since it is configured by electronic means, the temperature detection section and the circuit body can be separated, so it goes without saying that the position of the alarm circuit body can be freely installed.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional refrigerator temperature alarm device composed of a mechanical timer and a relay, and FIG. 2 is a circuit diagram showing an embodiment of the refrigerator temperature alarm device of the present invention. DESCRIPTION OF SYMBOLS 1...Power supply, 2...Bridge component for temperature detection, 3, 4...Comparator, 5...High temperature detection temperature setting part, 6...Low temperature detection temperature setting part, 7, 8...
Display device, 9...Timer element, 10...CR oscillation circuit, 13...Alarm circuit, 15...Switch circuit.

Claims (1)

[Claims] 1. A first comparator for high temperature detection that outputs an output when the temperature rise in the refrigerator exceeds a predetermined value, a second comparator for low temperature detection that outputs an output when the decrease in the temperature in the refrigerator becomes below a predetermined value, and the first comparator a timer element that starts counting based on the output of the comparator, counts up after a predetermined time and outputs it, and outputs the frequency division ratio lower than the predetermined time based on the output of the second comparator; the first comparator; When the output from the second comparator is output, the timer element becomes open and the predetermined time is determined, and the output of the second comparator turns the timer element into a closed state and sets the timer element from the predetermined time to the frequency division ratio. A temperature alarm device for a refrigerator, comprising a switch circuit for changing the temperature, and an alarm circuit for activating an alarm based on an output signal counted up by the timer element.