JPS5934937B2 - ice making control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ice-making control device, and more particularly, to an ice-making control device that can obtain ice cubes with a constant hole diameter throughout the year without being affected by changes in ambient temperature.

Automatic ice making machines are widely used in which an expansion valve, evaporator, compressor, condenser, etc. are connected and arranged in a ring to form a refrigeration system, and the water supplied to the ice making compartment is configured to continuously produce ice cubes. It has come to be.

By the way, this type of automatic ice maker usually controls the ice making time using a timer or thermostat, so changes in ambient temperature cause a prefix between the timer setting time and the actual ice making time. This has the disadvantage that the growth rate of the ice blocks varies, and in order to obtain ice blocks with a constant hole diameter, the timer must be adjusted each time, making the operation extremely complicated.

Furthermore, in order to eliminate this inconvenience, many ice-making control devices have been developed that automatically detect the ambient temperature using a temperature-sensitive element and use this detection signal to energize or de-energize the ice-making cycle and de-icing cycle. However, in this type of ice-making control device, as the ambient temperature changes, the pressure of the refrigerant flowing through the refrigeration system changes, and the ice-making chamber temperature changes accordingly. ,
For example, in a deicing cycle, there is a considerable time difference between when the grown ice leaves the ice making chamber and when the temperature of the ice making chamber reaches the deicing detection temperature.

That is, the conventional ice making apparatus has a drawback that when the ambient temperature falls, the time from when the ice block leaves the ice making chamber until the next ice making cycle is longer than when the temperature is high.

Therefore, the inventor conducted extensive research and devised an ice-making control device that can overcome the above problems, always obtain ice cubes with a constant hole diameter, and operate efficiently. At least two capacitors are used, and the time from the start of deicing to the completion of deicing and the time from the completion of deicing to the completion of ice making in the next ice making cycle are regulated by the charging time of each capacitor, and By controlling the charging time from a constant voltage value to a constant voltage value under the action of a temperature-sensitive element such as a thermistor that operates in response to changes in ambient temperature, appropriate ice-making control is always achieved in response to changes in ambient temperature. We discovered that it is possible to automatically adjust the

Therefore, a general object of the present invention is to provide an ice-making control device that can always obtain ice cubes with a constant hole diameter despite changes in ambient temperature and that can perform efficient ice-making operation. .

In order to achieve the above object, the ice making control device according to the present invention includes a first time constant circuit comprising a first outside temperature sensing element Th1 having negative resistance characteristics and a first charging/discharging element C1; a first voltage divider circuit, which includes a fixed resistor R2 and a variable resistor R1, and generates a first reference voltage across the variable resistor for setting the deicing time; The voltage across the discharge element and the first reference voltage are input and compared, and if the voltage across the first charge/discharge element is greater than the first reference voltage, one logic value is obtained; a first comparison amplifier AMP□ which outputs a first signal having the other logical value; and a first transistor circuit Tr1+
a first charging/discharging circuit 10 including; a second fixed resistor R9;
and a second time constant circuit comprising a second charging/discharging element C2;
It consists of a second outside temperature sensing element Th2 having negative resistance characteristics and a third fixed resistor R1', and generates a second reference voltage across the third fixed resistor that gives the ice making time. A second voltage divider circuit; a voltage across the second charging/discharging element and the second reference voltage are input and compared, and the voltage across the second charging/discharging element is higher than the second reference voltage. a second comparator amplifier A that outputs a second signal having the one logical value when the value is large and having the other logical value otherwise;
MP2; and a second charging/discharging circuit 12 including a second transistor circuit Tr2; and a reset terminal R to which the first signal is input; a set terminal S to which the second signal is input; refrigeration system Deicing is completed when the first signal has the one logical value and the second signal has the other logical value. An ice-making start logic signal, which is a logic signal, is output and held as an ice-making logic signal to deenergize the coil and close the solenoid valve, and the first signal has the other logic value and the first signal has the other logic value. When the second signal has one of the logical values, a deicing start logical signal, which is an ice making completion signal, is output and held, and is used as a deicing logical signal to energize the coil and open the solenoid valve. 1 output terminal Q;
and a bistable circuit having a second output terminal that outputs a signal having a logical value opposite to the output signal of the first output terminal; The charge/discharge element has a collector terminal and an emitter terminal connected between both ends thereof, and a base terminal connected to the first output terminal, and the ice making logic signal is transmitted from the first output terminal to the base terminal. When the voltage is applied, the first charge/discharge element is discharged, and the second transistor circuit has a collector terminal and an emitter terminal connected between both ends of the second charge/discharge element, and the second transistor circuit. a base terminal connected to an output terminal of the second transistor circuit, and when a signal having a logic value opposite to the deicing logic signal is applied from the second output terminal to the base terminal of the second transistor circuit. The second charge/discharge element is discharged, and the first charge/discharge element is discharged.
Alternatively, the first and second signals have logical values opposite to each other when the second charging/discharging element is in a discharging state.

Next, the ice making control device according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an electric circuit of an ice-making control device according to the present invention, in which a first charging/discharging circuit 10 basically has approximately the same configuration.
and a second charge/discharge circuit 12 and a bistable circuit 14, and the output conductors of the bistable circuit 14 that generate mutually inverted outputs are connected to the first charge/discharge circuit 10 and the second charge/discharge circuit 12, respectively. By doing so, the first charging/discharging circuit 10 and the second charging/discharging circuit 12 are configured to perform a charging operation or a discharging operation alternately.

However, one end of the coil 16 that operates the solenoid valve (not shown) provided in the hot gas bypass pipe of the refrigeration system is connected to one output terminal Q of the bistable circuit 14 connected and arranged in this way, and the coil The other end of 16 is connected to a DC power source.

Therefore, for example, when the other output terminal Q side of the bistable circuit 14 is at a low potential, the output terminal Q is at a high potential H, so no current flows through the coil 16, and as a result, the solenoid valve is closed.

Next, when a reset signal is input to the bistable circuit 14, the potential states of the output terminals Q and Q are reversed, and as a result, the solenoid valve becomes open.

Therefore, in the present invention, the input timing of the set signal and reset signal to the bistable circuit 14 is adjusted to the first timing.
It is regulated by each charging time of the charging/discharging circuit 10 and the second charging/discharging circuit 12.

The first charge/discharge circuit 10 connects in series a negative characteristic thermistor Th1 for detecting outside temperature and a capacitor C1, connects the negative characteristic thermistor Th to a DC power supply terminal, and grounds the capacitor C1.

The connection point between the negative characteristic thermistor Th1 and the capacitor C1 is connected to one input terminal of the comparator amplifier AMP1, and the other input terminal of the comparator amplifier AMP1 is grounded via a variable resistor R7 and connected to a DC power supply via a resistor R2. Connect to the terminal.

Furthermore, the output terminal of the comparator amplifier AMP1 is connected to the bistable circuit 14.
It is connected to the reset input terminal R of , and is also connected to the DC power supply terminal via a resistor R3.

Furthermore, a transistor Tr□ for discharging the capacitor C1 is provided, and the collector terminal of this transistor Tr1 is connected to the DC power supply terminal via a resistor R4, and the negative characteristic thermistor Th1 and the capacitor C1 are connected via a diode D1. The emitter terminal of the transistor Tr1 is connected to the ground via the resistor R5 and the emitter terminal of the transistor Tr1 is connected to the resistor R5.
The base terminal of the transistor Tr1 is grounded through a resistor R7 and connected to one output terminal Q of the bistable circuit 14 through a resistor R8.

The second charging/discharging circuit 12 includes a capacitor C2, a comparison amplifier A
MP2, transistor T r 2, diode D2, resistor R1', R3', R4', R6', R6'
, R7', R8 Thermistor Th2 and resistor R9 are used to configure a circuit substantially the same as the first charging/discharging circuit 10.

In addition, in the second charging/discharging circuit 12, compared to the first charging/discharging circuit 10, a resistor R9 is connected to a part corresponding to the negative characteristic thermistor Th1, a thermistor Th2 is connected to a part corresponding to the resistor R2, and the variable A fixed resistor R1' is connected to the part corresponding to the resistor R1, and the output terminal of the comparison amplifier AMP2 is connected to the set input terminal S of the bistable circuit 14, and the base terminal of the transistor Tr2 is connected to the bistable circuit through the resistor R8'. Connect to the other output terminal page of circuit 14.

Next, the operation of the circuit of this embodiment will be explained.

By applying power to the DC power supply terminal, the capacitors C7 and C2 of each charging/discharging circuit 10.12 are charged via the negative characteristic thermistor Th1 and resistor R9.

While capacitors C1 and C2 are charged to a constant voltage value,
The comparator amplifiers AMP, AMP2 do not operate, and therefore the input terminals S and R of the bistable circuit 14 maintain a high potential, so one of the output terminals Q and ( becomes a high potential and the other becomes a low potential. .

For example, when the output terminal Q of the bistable circuit 14 has a low potential as shown in Fig. 2, the solenoid valve opening/closing coil 16 is energized, so the solenoid valve is in the open state, and the ice making device is in the deicing operation state. .

On the other hand, by holding the output terminal Q at a high potential, a bias voltage is applied between the base and emitter of the transistor Tr2 of the second charging/discharging circuit 12, so that the transistor Tr2 is turned on and the collector of the transistor Tr2 is turned on. As a result of the potential dropping and diode D2 becoming conductive,
The charging voltage of capacitor C2 does not exceed the potential of the collector of transistor T r 2.

Further, while the output terminal Q of the bistable circuit 14 maintains a low potential, the transistor Tr1 of the first charging/discharging circuit 10 is OFF.
However, the charging voltage of the capacitor C1 increases over time, and this charging voltage becomes a high potential compared to the first reference voltage for setting the deicing time, which is the terminal voltage of the variable resistor R1 set in advance. When this happens, the comparator amplifier AMP1 operates to cause a current to flow through the resistor R3, thereby bringing the reset terminal R of the bistable circuit 14 to a low potential.

As a result, the potential states of the output terminals Q and Q of the bistable circuit 14 are reversed, the output terminal P becomes a low potential, and the output terminal Q
outputs an ice making start signal which is a high potential deicing completion signal,
The coil 16 is de-energized, the solenoid valve is closed, and the ice maker is brought into the ice-making state.

At the same time, the transistor T r of the second charge/discharge circuit 12
Since the capacitor C2 is turned off and the transistor Tr1 of the first charging/discharging circuit 10 is turned on, the capacitor C2 continues to be charged and the capacitor C1 is discharged.

Therefore, as shown in FIG. 2, the potential of the reset terminal R is low for a short period when the transistor Tr1 discharges the capacitor C1, and returns to a high potential after the discharge.

However, the logic value of the ice-making start signal from the output terminal Q is held as the ice-making logic signal.

This set state of the bistable circuit 14 is maintained for a period of time during which the charging voltage of the capacitor C2 rises to a second reference voltage value for providing ice-making time for operating the comparator amplifier AMP2.

Therefore, the charging time of the capacitor C2 to the second reference voltage value defines the ice making operation time (see FIG. 2).

Next, the charging voltage of capacitor C2 increases and resistor R1/
When the potential becomes higher than the second reference voltage for giving the ice-making time, which is the terminal voltage of .

Therefore, the output terminals of the bistable circuit 14 become high potential, and the output terminal Q outputs a deicing start signal which is a low potential ice making completion signal, the transistor Tr1 is turned off, and the capacitor C1 is charged. Transistor T r 2
is turned on and the capacitor C2 is discharged.

At this time, the direct solenoid valve opening/closing coil 16 is energized, the solenoid valve is opened, and the ice making apparatus performs ice removal operation.

In this case, the potential of the set terminal S is as shown in FIG.
The transistor Tr2 has a low potential for a short period of time while discharging the capacitor C2, and returns to a high potential after discharging.

However, the logical value of the deicing start signal from the output terminal Q is held as the deicing logic signal.

Therefore, in this case, the time until the capacitor C1 is charged to the first reference voltage value regulates the deicing operation time (see FIG. 2).

In addition, in the control circuit shown in FIG. 1, the resistance value of the capacitor C1 in series with the first charging/discharging circuit 10 changes according to changes in ambient temperature due to negative characteristics (see FIG. 3).
Because of the connection of the thermistor, the time constant of the charging circuit becomes smaller when the ambient temperature is high, and therefore the time it takes to raise its charging voltage becomes shorter (see Figure 4).

However, if the ambient temperature is low, the time constant of the charging circuit will be large and the time will be longer (see Figure 4C).

As a result, the charging voltage of the capacitor C1 changes exponentially, so by appropriately selecting and adjusting the resistance value of the variable resistor R1, the capacitor C1 changes when the ambient temperature is high and when the ambient temperature is low.
The difference in charging time can be adjusted to the desired size, and the time required to move on to making the next ice after ice falls from the ice tray, that is, the deicing operation time, does not become particularly long, especially when the ambient temperature is low. The amount of ice made per day will substantially increase.

In this embodiment, a thermistor Th is used as a resistor constituting a charging circuit for the capacitor C1.

The same effect as described above can also be obtained by connecting a variable resistor R1 connected to the input terminal of the comparator amplifier AMP1 instead, and connecting and arranging a negative characteristic thermistor Th to the connection portion of the variable resistor R1.

In other words, if the negative characteristic thermistor Th1 is used as the input resistance of the comparator amplifier AMP, the higher the ambient temperature becomes, the lower the terminal voltage becomes. Therefore, the time it takes for the terminal voltage of the capacitor C1 to reach the first reference voltage becomes shorter. It gets faster.

In addition, when the ambient temperature is low, the negative characteristic thermistor T
Based on the terminal voltage of h1, the time for the terminal voltage of capacitor C1 to reach the first reference voltage becomes longer, and an appropriate deicing time can be obtained.

In addition, in the control circuit shown in FIG. 1, since the thermistor Th2 similar to that used in the first charging/discharging circuit 10 is connected to the input terminal of the comparison amplifier AMP2 provided in the second charging/discharging circuit 12, the capacitor C2 is charged. The ice-making operation time is controlled by changing the terminal voltage of the resistor R1', which is compared with the voltage, according to the ambient temperature.

That is, when the ambient temperature is high, the terminal voltage of the resistor R1' becomes high, and it takes a long time for the charging voltage of the capacitor C2 to reach the second reference voltage value, thereby lengthening the ice making time.

Further, when the ambient temperature is low, the terminal voltage of the resistor R1' becomes low, and the time required for the charging voltage of the capacitor C2 to reach the second reference voltage value is shortened, thereby shortening the ice making time.

In this way, it is possible to obtain ice cubes with uniform hole diameters.

Further, when the output terminal Q of the bistable circuit 14 becomes a high potential, the ice making operation state is entered, and thereafter the same operation as described above is performed.

As described above, according to the device of the present invention, a thermistor whose resistance value is variable according to changes in the ambient temperature is used, and the terminal voltage of the capacitor of the charging/discharging circuit reaches a predetermined value due to the change in the resistance value of the thermistor. It is possible to perform ice making or deicing operations using this time, and it is possible to obtain ice cubes with a constant hole diameter throughout the year regardless of changes in ambient temperature. can be increased to

Although the preferred embodiments of the cooling control device according to the present invention have been described in detail above, the present invention is not limited to these embodiments, and can also be applied to a down-flow ice maker. Of course, the same effect can be obtained even if the condensation temperature is detected in addition to the ambient temperature.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram related to the device of the present invention, and FIG. 2 is a waveform diagram showing changes in the terminal voltages of capacitances C1 and C2 and the potentials of the S and R terminals and the Q and N terminals of the bistable circuit. Figure 3 is a characteristic curve diagram of the thermistor used as resistor R1,
FIG. 4 is a characteristic curve diagram showing the correlation between ambient temperature and deicing time. 10...First charge/discharge circuit, 12...Second charge/discharge circuit, 14...Bistable circuit, 16...
... Coil, Q. Q...Output terminal, S, R...Input terminal, Th1. Th2...Thermistor, C1, C2
・・・・・・Capacitor, AMPL. AMP2... Comparison amplifier, Trl, Tr2...
...Transistor, Dl, D2...Diode.

Claims (1)

[Claims] 1. First outside temperature sensing element Th1 having negative resistance characteristics
and a first time constant circuit comprising a first charging/discharging element C1;
a first voltage divider circuit comprising a first fixed resistor R2 and a variable resistor R1 and generating a first reference voltage across the variable resistor to set the deicing time; The voltage across the charging/discharging element and the first reference voltage are input and compared, and if the voltage across the first charging/discharging element is thicker than the first reference voltage, one logical value is obtained, and other than this. a first comparison amplifier AMP that outputs a first signal having the other logical value when; and a first transistor circuit Tr;
: A first charging/discharging circuit 10 including: a second fixed resistor R
9 and a second charging/discharging element C2; a second time constant circuit consisting of a second outside temperature sensing element Th2 having negative resistance characteristics and a third fixed resistor R7', which gives ice making time. a second voltage divider circuit that generates a second reference voltage across the third fixed resistor; a voltage across the second charging/discharging element and the second reference voltage are input and compared; and a second signal having the one logical value when the voltage across the second charging/discharging element is higher than the second reference voltage, and outputting a second signal having the other logical value in other cases. A second charging/discharging circuit 12 including a comparison amplifier AMP2; and a second transistor circuit Tr2; and a reset terminal R to which the first signal is input; a set terminal S to which the second signal is input; Connected to a coil 16 that opens and closes a solenoid valve provided in a hot gas bypass pipe of a refrigeration system, except when the first signal has the one logical value and the second signal has the other logical value. Outputting and holding an ice-making start logic signal, which is an ice completion logic signal, and using it as an ice-making logic signal, deenergizes the coil and closes the solenoid valve, and the first signal has the other logic value. When the second signal has one of the logical values, a deicing start logical signal, which is an ice making completion signal, is output and held, and is used as a deicing logical signal to energize the coil and open the solenoid valve. and a second output terminal Q that outputs a signal having a logical value opposite to the output signal of the first output terminal; The transistor circuit has a collector terminal and an emitter terminal connected between both ends of the first charge/discharge element, and a base terminal connected to the first output terminal, and the ice-making logic signal is connected to the first charge/discharge element. The second transistor circuit discharges the first charging/discharging element when the voltage is applied from the output terminal to the base terminal, and the second transistor circuit has a collector terminal connected between both ends of the second charging/discharging element. and an emitter terminal and a base terminal connected to the second output terminal, wherein a signal having a logic value opposite to the deicing logic signal is transmitted from the second output terminal to the second transistor circuit. When the voltage is applied to the base terminal, the second charging/discharging element is discharged, thereby causing the first or second charging/discharging element to discharge.
An ice-making control device characterized in that the first and second signals have logical values opposite to each other when the charging/discharging element is in a discharging state.