JPH0579903B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an operation control device for an ice maker that causes ice making water to flow down along a plate to form ice on the surface of the plate.

(b) Prior Art For example, in Japanese Patent Publication No. 58-17391, a contact point of a thermocouple is arranged in the freezing part of an ice-making compartment, and the contact point of the thermocouple is arranged in the freezing part of the ice-making compartment, and the temperature of the thermocouple that occurs in response to the temperature change of the ice formed in the ice-making compartment is When the electromotive force reaches a certain value, a certain output voltage is generated in the differential amplifier circuit connected to the thermocouple, and this output voltage energizes the relay to open the hot gas valve and remove ice. An automatic electronic ice making control device is disclosed.

(c) Problems to be Solved by the Invention In the above-mentioned conventional technology, for example, when the outside air temperature drops in winter, the temperature in the ice-making compartment also drops as ice-making operations occur, so the temperature of the thermocouple also gradually drops, causing the above-mentioned When the electromotive force of the thermocouple reaches a certain value, even though ice formation has not finished,
There was a problem that the ice making operation would stop due to malfunction. Furthermore, when the ice-making operation is completed and the ice falls from the ice-making compartment due to the de-icing operation, an appropriate detection device is required to detect this state, and the configuration of the automatic electronic ice-making control device is required. The problem was that it became complicated. The present invention aims to solve the above problems.

(d) Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides an ice making machine in which ice-making water flows down along a plate to form ice on the surface of the plate. A self-heating type thermistor sensor provided at a predetermined distance from the surface of the thermistor sensor, and an input delay circuit that inputs the terminal voltage of the thermistor sensor to one input terminal and outputs a change in the terminal voltage with a delay. a comparator that inputs the terminal voltage to one input terminal and inputs the output of the amplifier to the other input terminal, and operates based on the output of the comparator. The present invention provides an operation control device for an ice making machine, which is equipped with a switch circuit for controlling ice making operation.

(e) Operation When the comparator outputs a high-level signal and the switch circuit operates to perform ice-making operation, ice gradually grows on the surface of the plate, and the thermistor sensor detects water flowing on the surface of the ice. or when it comes into contact with ice,
The thermistor sensor is cooled by water or ice and the terminal voltage increases. At this time, the rise of the positive input voltage of the amplifier lags behind the negative input voltage due to the operation of the input delay circuit, and the negative input voltage of the comparator rises faster than the positive input voltage.
When the difference between the negative side input voltage and the positive side input voltage reaches a predetermined value, the comparator outputs a low level signal with a delay from the contact between the thermistor sensor and water or ice, and the switch circuit operates to start ice making operation. Then move on to ice removal operation. When ice falls during ice removal operation, the temperature of the thermistor sensor rises due to self-heating, and the terminal voltage gradually decreases. At this time, the positive input voltage of the amplifier changes to the negative input voltage due to the operation of the input delay circuit. When the input voltage on the positive side is higher than the input voltage on the negative side and the difference between the respective input voltages reaches a predetermined value, a high level signal is output with a delay from the deicing of the comparator, and the switch circuit It operates and ice making operation starts again.

(F) Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on FIGS. 1 to 3.

Figure 1 is a schematic side view of the ice making device, where 1 is a plate on which ice is formed, 2 is an upper water storage tank provided on the top of plate 1, and 3 is provided below plate 1. The lower water storage tank 3 is a lower water storage tank with an opening on the top surface, and this lower water storage tank 3 receives and stores ice-making water flowing down from the surface of the plate 1. Further, 4 is a water pipe installed between the lower water storage tank 3 and the upper water storage tank 2, and a water pump 5 is provided in this water pipe 4. Furthermore, reference numeral 6 denotes a refrigeration system installed for ice-making operation.
The evaporation pipe 10 is provided in a cooling space 12 formed by the plate body 1 and the outer plate 11, and a plurality of ice making nuclei 13, 13 are attached to appropriate positions on the plate body 1. It is caulked on the back. Here, the ice-making cores 13, 13 are made of a metal with good thermal conductivity such as copper, for example, and are fitted into openings formed in a plurality of places in the plate 1, and their surfaces are exposed on the surface of the plate 1. There is. Further, a self-heating type thermistor sensor S is provided at a distance from the plate 1 and facing the ice-making cores 13, 13.

Further, FIG. 2 shows a schematic operating circuit of the ice making device, in which 15 is a constant current diode connected in series with the temperature sensor S, 16 is an amplifier, 17 is a comparator that is a hysteresis comparator, and the terminal voltage of the thermistor sensor S is Amplifier 1 through the first resistor R ₁
It is input to the negative input terminal of 6, and the second resistor R ₂ and capacitor provided as an input delay circuit.
It is input to the positive input terminal of the amplifier ₁₆ via a charging/discharging circuit consisting of
is input to the negative input terminal of Further, R ₃ is a third resistor forming a feedback circuit of the amplifier 16, R ₄ is a fourth resistance, and R ₅ is a fifth resistance forming a feedback circuit of the comparator 17. The output terminal of the comparator 17 is connected to the excitation coil of the relay R via the sixth resistor _R6 .
NPN transistor that controls energization to RC
Connected to the base of the TR. 20 is a power supply control circuit for the water pump 5 and the compressor 7;
is a relay switch of the above-mentioned relay R.

When the ice-making device starts ice-making operation, the thermistor sensor S is energized, and the temperature of the sensor increases slightly due to self-heating, its resistance value decreases, and the terminal voltage gradually decreases. and,
The terminal voltage is input to the negative input terminal of the comparator 17, and is also input to the amplifier ₁₆ via the first resistor R1.
Further, the drop in the terminal voltage is delayed by the second resistor R ₂ and the capacitor C ₁ and is input to the positive input terminal of the amplifier 16 . Therefore, the output voltage of the amplifier 16 is higher than the voltage at the negative input terminal of the comparator 17 (hereinafter referred to as the negative input voltage), and when the difference between the output voltage and the negative input voltage of the comparator 17 exceeds a predetermined value, , the output of the comparator 17 becomes a high level signal (hereinafter referred to as an H signal).

When the comparator 17 outputs an H signal, the sixth resistor
Transistor TR is turned on through _R6 , and relay coil RC is energized. And relay switch RS
is turned on, the water pump 5 and the compressor 7 are energized and start operating, and the water sent from the lower water storage tank 3 to the upper water storage tank 2 flows down the surface of the plate 1, and the refrigeration device 6 starts operating. The refrigerant circulates, and ice making starts from the ice making cores 13, 13 of the plate 1.

As the water pump 5 and compressor 7 operate, ice gradually grows as shown in FIG. , the thermistor sensor S is rapidly cooled by the ice or water, exceeding the self-heating. Therefore, the resistance value of the thermistor sensor S increases, and the terminal voltage increases. At this time, the voltage input by the positive input terminal of the amplifier 16 (hereinafter referred to as positive input voltage)
Since the rise in voltage is via the second resistor R ₂ and the capacitor C ₁ , the rise in the negative side input voltage is delayed due to charging of the capacitor C ₁ , and the rise in the output voltage of the amplifier 16 is also delayed. Therefore, the negative input voltage of the comparator 17 increases faster than the output voltage of the amplifier 16, and when the difference between the negative input voltage and the output voltage exceeds a predetermined value,
Almost simultaneously with the contact of the thermistor sensor S with ice or water, the output of the comparator 17 becomes a low level signal (hereinafter referred to as an L level signal). Then, the base voltage of the transistor TR becomes an L level signal, the transistor TR is turned off, the relay coil RC is de-energized, and the relay switch RS is turned off. Therefore, the operation of the water pump 5 and the compressor 7 is stopped, and the ice making operation is ended.

When the ice-making operation is finished and the compressor 7 is stopped, water flows into the cooling space 12 from above and the ice removal operation is started. When the temperature of the evaporation pipe 10 rises and the temperature of the plate 1 rises, the plate 1, the ice falls into an ice storage (not shown). When the ice falls, the temperature of the thermistor sensor S increases due to self-heating, and at this time, the terminal voltage of the thermistor sensor S decreases,
Since the positive input voltage of the amplifier 16 decreases later than the decrease of the negative input voltage due to the discharge of the capacitor C ₁ in the charging/discharging circuit consisting of the second resistor R ₂ and the capacitor C ₁ , the output voltage of the amplifier 16 is lower than the comparator output voltage. The negative input voltage of the comparator 17 quickly decreases, and when the difference between the output voltage and the negative input voltage exceeds a predetermined value, the comparator 17 outputs an H level signal almost at the same time as the ice falls. This H level signal turns on the transistor TR, operates the relay R in the same manner as described above, and the water pump 5 and compressor 7 start operating, thereby starting the ice making operation. Thereafter, the ice-making operation is similarly controlled based on the temperature detected by the temperature sensor S.

Therefore, during ice-making operation, even when the temperature inside the ice-making chamber decreases due to a decrease in outside air temperature, the thermistor sensor S remains unaffected until the ice formed on the plate 1 or the water flowing on the surface of the ice directly contacts the thermistor sensor S. Since S is self-heating, the terminal voltage does not change significantly due to the temperature change, and as the ice grows, the ice or water flowing on the surface of the ice comes into contact with the thermistor sensor S, causing the temperature to drop rapidly. Since the growth of ice is detected when the ice is grown, it is possible to detect the growth of ice regardless of changes in the outside temperature, and it is possible to always obtain substantially uniform ice. When the thermistor sensor S is no longer in contact with ice or water, the temperature of the thermistor sensor S quickly rises due to self-heating of the thermistor sensor S, and the ice-making operation can be started. In order to detect ice growth and ice falling, the operation control device can be simplified.

Also, during ice-making operation or ice-removal operation, the change in the terminal voltage of the thermistor sensor S is delayed by the charging/discharging circuit of the second resistor R ₂ and the capacitor C ₁ and is inputted to the positive input terminal of the amplifier. This is because the change in the output voltage of the comparator 17 is delayed from the change in the negative input voltage of the comparator 17, and the output of the comparator 17 is changed by the difference between the respective voltages, which is not affected by changes in outside temperature, and the transistor TR is operated. , the thermistor sensor 5 as the outside temperature changes.
Even if the terminal voltage changes, ice growth or ice falling can be accurately detected, and as a result, ice making operation or ice removal operation can be accurately controlled.

(G) Effects of the Invention Since the present invention is an operation control device for an ice maker configured as described above, even if the outside temperature drops due to seasonal changes, the thermistor sensor self-generates heat, so the outside temperature The temperature drop of the thermistor sensor due to the decrease in temperature is small, and the change in the output of the amplifier due to the change in outside temperature is small. After the ice falls, the output of the comparator changes due to the temperature rise due to self-heating of the thermistor sensor, and the next ice-making operation can be started promptly. Changes in the terminal voltage of the sensor are delayed by an input delay circuit and sent to an amplifier, and the delayed signal is output from the amplifier to one input terminal of the comparator, and the thermistor sensor without delay is output to the other input terminal. terminal voltage is input, and the output of the comparator changes based on the difference between the respective input voltages to detect the completion of ice making and ice removal, so even if changes in outside air temperature etc. affect the thermistor sensor. , ice growth or ice falling can be accurately detected regardless of changes in the outside temperature, etc. As a result, the operation of the ice maker can be accurately controlled.

[Brief explanation of drawings]

1 to 3 show an embodiment of the present invention,
Fig. 1 is a schematic vertical cross-sectional view of the ice making device, Fig. 2 is a schematic operating circuit diagram of the ice making device, and Fig. 3 shows changes in the output of the amplifier, the negative side input voltage of the comparator, and the changes in the output signal of the comparator. FIG. 1... Plate, S... Thermistor sensor, R ₂ ,
C ₁ ...Second resistor constituting the charge/discharge circuit, capacitor, 16...Amplifier, 17...Comparator, TR...
...transistor.

Claims (1)

[Claims] 1. In an ice maker that causes ice-making water to flow down along a plate to form ice on the surface of the plate, a self-heating thermistor sensor provided at a predetermined distance from the surface of the plate; and the thermistor. An amplifier that inputs the terminal voltage of the sensor to one input terminal and inputs the terminal voltage to the other input terminal via an input delay circuit that outputs a change in the terminal voltage with a delay, and inputs the terminal voltage to one input terminal. and a comparator that inputs the output of the amplifier to the other input terminal, and a switch circuit that operates based on the output of the comparator to control ice-making operation. Control device.