JPS6139591B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling control device, and more particularly to a control device for a cooling device equipped with an electric stirring impeller that stirs a cooled liquid near the freezing point temperature.

Conventionally, in water coolers, etc., the water temperature was converted into an electrical signal using a temperature sensor to control the compressor of the cooler, but if the water temperature is close to the freezing point, even a slight change in water temperature will freeze and stir the water. The impeller for the cooling system was locked, and the cooling system's operation control based on water temperature detection was unable to bring the water temperature in the cooling system close to the freezing point.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cooling control device that can operate a liquid near its freezing point or in a state where some ice is present.

A feature of the present invention is to detect the load current of the motor by utilizing the fact that the load current of the motor that drives the impeller for stirring the liquid changes in response to changes in water temperature when ice is mixed in the liquid. The reason is that the cooling machine can be controlled by

The following will be explained based on the embodiments shown in the drawings.
In FIG. 1, 1 is a liquid stirring tank, and the shaft of a stirring electric motor 3 attached to the side wall of this tank via a heat insulating material 2 extends into this tank, and rotates a stirring impeller 4. It's summery. 5 is an auxiliary tank for supplying new liquid into the stirring tank 1, and 6 is an outlet for taking out the liquid that has been cooled and stirred in the stirring tank 1. A cooler 7 is equipped with a compressor, a radiator, a driving electric motor, etc., and a cooling pipe 7a is introduced into the stirring tank 1 to cool the liquid. 8 is the stirring electric motor 3 and the cooler 7
This is a control circuit for controlling the motor (compressor drive motor), and its details are shown in Fig. 2. In Fig. 2, the stirring electric motor 3 is connected to a large output terminal H with a high output specification that magnetically saturates the motor core, and a small output terminal L that allows the current to flow according to the load without magnetically saturating the iron core. A motor winding with a tap (not shown) is provided, a common terminal is connected to a power supply line 10, and a large output terminal H and a small output terminal L are connected to fixed contacts 11H and 11L of a switching relay 11, respectively. The movable contact 11A of the switching relay 11 is connected to the power supply line 12. Reference numeral 13 denotes a relay coil for controlling the operation of the compressor driving motor of the cooler 7, and is connected between the power lines 10 and 12 via the normally open contact 11B of the switching relay 11. 14 is a transformer for auxiliary power supply, and the primary coil 14A is connected between the power lines 10 and 12, and the low voltage obtained in the secondary coil 14B is rectified by a diode 15, smoothed by a capacitor 16, and then connected to the power lines 17 and 18. Apply DC auxiliary voltage to Resistors 19, 20, 21 are power line 1
It is connected in series between 7 and 18 to apply a reference voltage to the input terminal (-) of the operational amplifier 22. 23 is a current transformer that detects the magnitude of the load current flowing through the stirring motor 3, and its output voltage is rectified by a diode 24, smoothed by a capacitor 25 and a resistor 26, and then input to the input terminal (+) of the operational amplifier 22. .
27 is a timer whose output from the operational amplifier 22 is input to the input terminal R, and when this input becomes high level, it is set and the output terminal L is set to the low level.
The output terminal H is set to high level. Output terminal H controls the charge voltage of capacitor 25 via diode 28. Output terminal L of timer 27 controls transistor 30 via resistor 29 and relay coil 1.
Turns 1C current on and off. Relay coil 11
C operates the contacts 11A and 11B,
When the current of the coil 11C is turned off, the contact 11A,
11H is closed and contact 11B is open.

In the above configuration, the stirring tank 1 is filled with liquid and is stirred by the impeller 4 while being cooled by the cooling pipe 7a. The cooled liquid is taken out from the outlet 6, and new liquid is replenished into the stirring tank 1 from the auxiliary tank 5. The liquid in the stirring tank 1 is cooled to such an extent that part of it turns into ice, and in order to prevent the impeller 4 from locking due to freezing, the cooler 7 is controlled by the control circuit 8 as follows. Ru.

When AC power is applied to the power lines 10 and 12, the current in the relay coil 11C is off at that moment, so the motor 3 starts with high output at the H terminal. And since the starting current is large, current transformer 2
3 is large, the output of the operational amplifier 22 temporarily becomes high level, and the output terminal L of the timer 27 becomes low level. Therefore, the transistor 30 is off and no current flows through the relay coil 11C, the stirring motor 3 is operated at the H terminal, the relay coil 13 is also off and the cooler 7 is not operated. When the set time (3 to 4 minutes) of the timer 27 has elapsed, the output L of the timer 27 becomes high level, current flows through the relay coil 11C, contacts 11A, 11L, and 11B close, and the motor 3 is loaded with low output. The cooler 7 is operated with a current corresponding to the current. As the cooling in the stirring tank 1 progresses and the amount of ice increases, the load on the impeller 4 increases, and as a result, the load current on the motor 3 also increases.
The generated voltage also increases. As a result, when the terminal voltage of the capacitor 25 becomes larger than the reference voltage applied to the input terminal (-) of the operational amplifier 22, the output of the operational amplifier 22 becomes high level and the timer 27 is set. As a result, the output terminal L of the timer 27 becomes low level, and the relay coil 1
1C current is turned off, contact 11B is turned off, and contact 1
1A is in contact with contact 11H. Cooler 7 stops,
The stirring electric motor 3 is operated with a high output terminal H. Then, after the time set by the timer 27, current is again applied to the relay coil 11C, and the cooler 7 is operated.
The stirring electric motor 3 is switched to the low output terminal L. By repeating such operations, the liquid in the stirring tank 1 is controlled to be in a state in which ice is mixed therein.

On the other hand, when the set time elapses after the timer 27 is set, the output terminal H becomes low level and the capacitor 25 is discharged via the diode 28. Therefore, the input voltage (+) of the operational amplifier 22 falls, the operational amplifier 22 is inverted, and the timer 20 is reset. When the timer 27 is reset, the output terminal H becomes high level and the capacitor 26 stops discharging. For this reason, when the stirring motor 3 is switched to the low output terminal L, the capacitor 25 is discharged by the diode 28 even if the input voltage (+) of the operational amplifier 22 is higher than the input voltage (-). Output is inverted and timer 2
7 is reset. Therefore, if the load on the electric motor 3 is large when the cooler 7 is turned on, the cooler 7 is turned off again and the electric motor 3 is operated at the high output terminal H.

As described above, in the present invention, the high output terminal H and the low output terminal L are drawn out from the stirring electric motor 3, and the control circuit 8 is connected to the coil 1 that switches between the two terminals.
1C, and a current transformer 23 that detects the load current of the stirring motor 3, and when the load current of the stirring motor 3 exceeds a predetermined value, the output of the current transformer 23 is changed to Therefore, the coil 11C of the switching relay 11 selects the high output terminal H of the stirring motor 3, stops the cooler 7, and activates the timer 27, and after the set time of the timer 27 has elapsed, the operation starts again. Select the low output terminal L of the stirring motor 3, and turn on the cooling machine 7.
The system is configured to operate a cooling control system that allows the liquid to be mixed with ice, prevents the impeller and stirring motor from locking up due to freezing, and is safe and capable of stably supplying cold water near the freezing point. This is something that can be provided.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is an overall configuration diagram of a cooling device, and FIG. 2 is a control circuit diagram. 1... Stirring tank, 3... Stirring electric motor, 4... Impeller,
8... Control circuit, 22... Operational amplifier, 23... Current transformer, 27... Timer.

Claims (1)

[Claims] 1. A liquid stirring tank 1 having a liquid inlet and an outlet, a stirring impeller 4 disposed in the liquid stirring tank 1, and a stirring device that rotates the stirring impeller 4. electric motor 3 and a cooler 7 that cools the water in the stirring tank 1
and a control circuit 8 for controlling the operation and stop of the cooler 7, in which a high output terminal H and a low output terminal L are drawn out from the stirring motor 3, and the control circuit 8 connects both terminals. It includes a switching relay 11 having a switching coil 11C, and a current transformer 23 that detects the load current of the stirring motor 3, and when the load current of the stirring motor 3 exceeds a predetermined value, the current transformer 23 detects the load current of the stirring motor 3. Depending on the output, the coil 11C of the switching relay 11 selects the high output terminal H of the stirring motor 3 and stops the cooler 7,
The cooling control device is characterized in that the timer 27 is activated, and after the set time of the timer 27 has elapsed, the low output terminal L of the stirring electric motor 3 is selected again to operate the cooler 7.