JPH11281227A - Freezing and refrigerating show case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the temperature within a refrigerator with high accuracy regardless of the set in-refrigerator temperature, by ventilating the chill, controlling the show case to raise the number of revolutions when dropping the in-refrigerator temperature to the preset objective value and to lower the number of revolutions when elevating it. SOLUTION: The opening and closing of a solenoid value 9 are performed by controlling the number of revolutions of a blower 4. For that purpose, the drive motor 4a of the blower 4 is connected to the output side of a controller 8. The drive motor 4a is set to the number of revolutions being set separately for each temperature in a controller 8 so as to control the temperature within a refrigerator 5 to be close to the objective value. This show case is equipped with a blower regulator 11 as a number-of-revolutions control circuit, and the drive motor 4a is connected to the output side of the controller 8. Moreover, the blower regulator 11 is connected to a power source 10 through a power source part 12 annexed to it. It is preferable to use the average value of the temperatures detected with each of the temperature sensors 6 and 7 at a blowout port. If it is the same as the average temperature value, to the objective value set in advance in the controller 8, the blower rotates with the reference number of revolutions without changing the number of its revolutions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frozen or refrigerated showcase, and more particularly to an improvement in temperature control in a refrigerator.

[0002]

2. Description of the Related Art Conventionally, a method disclosed in Japanese Patent Application Laid-Open No. 5-272853 is known for controlling the internal temperature of a refrigerator and a refrigerator. As can be seen from the above publication, the internal temperature control is basically performed by controlling the opening and closing of a solenoid valve for opening and closing a refrigerant flow pipe of a refrigeration cycle provided in a case.

That is, as shown in FIG. 3, this kind of case is provided with a cooler (refrigerant evaporator) in a cool air passage 2 formed between an outer case and an inner case of the case body 1. 3 is provided, and cool air cooled by the cooler is circulated by a blower 4 through an opening 1a for putting in and out of a product on a front surface or an upper surface, and cools the inside of the refrigerator 5 and flows to the cooler 3. Temperature control is performed by controlling the refrigerant with an electromagnetic valve. 4a is a motor for driving the blower 4. An outlet temperature sensor 6 and an inlet temperature sensor 7 are provided for controlling the temperature in the refrigerator.

FIG. 4 shows a conventional internal temperature control circuit of a refrigerator-freezer case.
As shown in FIG. 1, a control device 8 comprising a microcomputer or the like is provided. The input device of the control device is connected with temperature sensors -6 and 7 for the air outlet and the suction port, and the output device has a solenoid valve. 9 is connected, the opening and closing of the solenoid valve 9 is controlled by a detection signal of each temperature sensor based on a preset temperature, that is, a target value (set temperature), and the flow rate of the refrigerant flowing through the cooler 3 is adjusted. . Reference numeral 10 denotes a power supply, and the control device 8 and the blower 4 were operated by the power supply, and the blower 4 was driven independently of the control of the solenoid valve 9.

[0005]

Even after the solenoid valve 9 is closed in such internal temperature control, refrigerant remains in the cooler 3 and the residual refrigerant evaporates, thereby circulating cool air. , So the inside 5 keeps cooling down,
Therefore, high-precision temperature control is impossible, and there is a limit to high-precision temperature control.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and therefore, the inside temperature control is performed with relatively high accuracy regardless of a preset inside temperature value. It is an object of the present invention to provide a frozen and refrigerated showcase.

[0007]

In order to achieve the above-mentioned object of the present invention, a refrigerating and chilling case according to the present invention controls the internal temperature of a refrigerator by controlling the opening and closing of a solenoid valve for opening and closing a refrigerant flow pipe. In the refrigerating and refrigeration case described above, the rotation speed of the drive motor of the blower for circulating cool air is made variable, and when the internal temperature is lowered to a preset target value, the rotation speed is increased. When raising the internal temperature to the target value and raising the internal temperature to the target value, it is characterized in that the rotational speed is controlled by the internal temperature so as to reduce the rotational speed, so that the amount of cool air can be adjusted. The effect of the refrigerant remaining in the cooler when the valve is closed is minimized.

In a preferred aspect of the present invention, the rotation speed of the drive motor of the blower is controlled by chopper control, and in another preferred aspect, the internal temperature used for controlling the rotation speed is controlled. The average value of the temperature of the outlet temperature sensor and the average temperature of the inlet temperature sensor is used, and in still another preferred embodiment, the drive motor of the blower is used.
The control of the rotation speed of the motor is performed in conjunction with the opening / closing control of the solenoid valve.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIGS. 1 and 2 show a control circuit for controlling the internal temperature of a refrigerator-freezer case according to the present invention.
As shown in (1), the opening and closing control of the solenoid valve 9 is performed by the control device 8 which is preferably constituted by a microcomputer, and the temperature of the interior 5 is controlled. Therefore, in addition to the power supply 10, the temperature sensor -6 at the outlet and the temperature sensor -7 at the suction port are connected to the input side of the control device 8 as in the prior art.
The configuration is such that the temperature of the cool air at the outlet and the inlet is detected and input to the control device 8. An electromagnetic valve 9 is connected to an output side of the control device 8.

The control of the opening and closing of the solenoid valve 9 in this control circuit is also performed by comparing the preset target value of the internal temperature with the temperature value detected by the temperature sensors -6 and 7 and comparing the target value with the target value. When the internal temperature is low, the solenoid valve 9 is closed to reduce the flow rate of the refrigerant to the cooler 3, and the internal temperature is controlled to increase to approach the target value.

The present invention supplements the internal temperature control by the opening / closing control of the solenoid valve 9 by controlling the rotation speed of the blower 4. Therefore, as shown in FIG. The drive motor 4a of the blower 4 is connected. The drive motor 4a is set so that the rotation speed set in advance by the controller 8 for each temperature is controlled so that the temperature of the interior 5 is controlled near the target value.

In order to control the rotation speed of the blower 4, it is preferable to use chopper control.
As shown in FIG. 2, a blower control unit 11 is provided as a rotation speed control circuit, and the drive motor 4 is controlled via the control unit.
a is connected to the output side of the control device 8. The blower control unit 11 is connected to a power supply 10 via a power supply unit 12 attached to the blower control unit 11.

The control of the rotation speed of the drive motor 4a is performed by a chopper.
When performing the control, the duty (duty ratio) of the control signal output from the control device 8 is made variable, and the average voltage applied to the drive motor 4a by the control unit 11 is changed by the variable duty. The rotation speed of the drive motor, and thus the rotation speed of the blower 4, is varied. If this chopper control is used, the average voltage to be applied can be changed with a very simple configuration, and it has a function of forcibly turning on and off at a high speed and at a high frequency.

Preferably, the average value of the temperature detected by the temperature sensor 6 at the outlet and the temperature detected by the temperature sensor 7 at the suction port is used as the internal temperature of the case. Regarding the output of the control device 8, if the average value of the temperature is the same as the target temperature value set in advance in the control device 8, the rotation speed of the blower 4 is not changed, and the fan 4 rotates at the reference rotation speed. Does not change, but if it differs from the target value, the duty of the control signal is changed according to the temperature difference (± ΔT).

That is, if the average value of the temperature is lower than the target value, the duty of the control signal is reduced in accordance with the temperature difference, the rotation speed of the drive motor 4a is reduced, and the air volume of the cool air is reduced. Reduce the temperature in the refrigerator and bring it closer to the target value. Conversely, if the average value is higher than the target value, the duty of the control signal is increased in accordance with the temperature difference, the rotation speed of the drive motor 4a is increased, and the internal temperature is reduced. The temperature is adjusted so as to approach the target value, and in any case, to keep the temperature in the refrigerator close to the target value and appropriately maintain the temperature.

In one example, when the internal temperature rises and the temperature difference ΔT from the target value is 2 degrees (° C.) or more, the duty of the control signal at the basic rotation speed is set to 40%. Then, the duty of the control signal output from the control device 8 is reduced by 50%.
To increase the average voltage applied to the drive motor 4a to accelerate the motor rotation speed by 10%. When the temperature in the refrigerator is 1 degree or 1 to 2 degrees higher than the target value, the motor rotation speed is 3 to
Accelerate 5%. The target value varies depending on various conditions. In one example, the target value is -20 ° C. for a frozen case and 0 ° C. for a refrigerated case. On the other hand, when the internal temperature is lowered to be lower than the target value by 2 degrees or more, the duty of the control signal is changed to 30%, and the average voltage to be applied is lowered to reduce the motor speed. Is reduced by 10%.

If the chopper control is used for controlling the number of rotations of the blower 4 as in the above-described embodiment, high-speed, high-frequency, and fine-grained control of the number of rotations is possible with a simple configuration. It is also possible to change the rotation speed by another method, for example, by performing voltage control via a transformer, and it is therefore said that the rotation speed control of the blower is not limited to the chopper control. Not even.

It is preferable to use the average value of the cool air temperature at the air outlet and the cool air temperature at the suction port as the temperature in the refrigerator because it can be regarded as a value close to the average temperature value of the whole region of the refrigerator. Obviously, in some cases, a temperature sensor may be installed at another position, for example, at an appropriate position in the refrigerator, and the temperature at that position may be represented.

Further, the drive mode of the blower 4 as described above
The rotation speed control of the motor 4a may be performed independently of the opening and closing control of the solenoid valve 9, but may be performed in conjunction with the opening and closing control of the solenoid valve 9 if desired. In that case, the control device 8 detects that the inside temperature, for example, the average value of the temperature detection values of the two temperature sensors -6 and 7 has a predetermined temperature difference, for example, 2 ° C. difference from the target value. At this time, the control device 8 simultaneously outputs to the solenoid valve 9 and the control unit 11 to open and close the solenoid valve 9 and change the rotation speed of the blower 4. Make adjustments.

For example, when the internal temperature is lower than the target value by a predetermined temperature, the solenoid valve 9 is closed to stop the cooling operation in the cooler 3, and the duty of the control signal is lowered to reduce the blower 4 as described above. Decrease the speed. As described above, since both the cooling action and the flow rate of the cool air act on the temperature control, a remarkable temperature change occurs, and there is an advantage that the temperature inside the refrigerator can be quickly brought close to the target value. Further, when the solenoid valve 9 is closed, even if the refrigerant remaining in the cooler 3 evaporates and the cooling action remains, the blowing capacity is reduced. Therefore, the influence of the remaining refrigerant on the internal temperature is small. Thus, a highly accurate temperature control is possible.

[0021]

As described above, according to the present invention, in addition to controlling the opening and closing of the solenoid valve, the amount of circulating cool air is controlled, and when the temperature in the refrigerator is lower than the target value, the amount of cool air is reduced. The internal temperature is rapidly increased to approach the target value, and when the internal temperature is higher than the target value, the amount of cool air is increased and the internal temperature is rapidly decreased to approach the target value. Therefore, the internal temperature is appropriately maintained at or near the target value. In addition, when the solenoid valve is closed due to the internal temperature being too low, the rotation speed of the blower is reduced, so that the refrigerant remaining in the cooler has little effect on the internal temperature at that time, and the temperature with high accuracy Enable control.

If the chopper control is used for the rotation control of the blower, the rotation speed can be controlled at a high speed and at a high frequency with a simple configuration, and the rotation speed control can be performed finely and suitably.

By using the average value of the temperatures at the air outlet and the suction port of the cold air as the internal temperature to be compared with the target value in the internal temperature control, the average value is calculated based on the average temperature of the whole area of the internal space or extremely. Since it can be considered as a close temperature,
The internal temperature can be effectively maintained at the target value.

Since the rotation speed control of the blower is linked to the opening / closing control of the solenoid valve, the cooling operation in the cooler and the air volume adjustment of the circulating cool air are simultaneously performed. And the time required to deviate from the target value is reduced, and the internal temperature is suitably maintained at or near the target value.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a control circuit of a refrigerator-freezer case according to the present invention.

FIG. 2 is a configuration diagram of a chopper control circuit provided in the control circuit of FIG. 1;

FIG. 3 is a longitudinal sectional view showing an example of a frozen and refrigerated showcase.

FIG. 4 is a block diagram showing a conventional control circuit for controlling the internal temperature of a refrigerator-freezer case.

[Explanation of symbols]

 4: Blower 4a: Driving motor of blower 5: Inside of chamber 8: Control device 9: Solenoid valve 11: Blower control unit

Claims (4)

[Claims] In a refrigerating and refrigerating case in which the temperature in a refrigerator is controlled by opening and closing an electromagnetic valve for opening and closing a refrigerant flow pipe, rotation of a drive motor of a blower for circulating cool air. When the internal temperature is reduced to a preset target value, the rotation speed is increased so that the rotation speed is increased, and when the internal temperature is increased to the target value, the rotation speed is decreased so as to decrease the rotation speed. A refrigerating and chilling case, characterized in that the number of cold air can be adjusted by controlling the number. 2. The refrigerating and chilling case according to claim 1, wherein the number of rotations of a drive motor of the blower is controlled by chopper control. 3. An air outlet temperature sensor as the inside temperature.
2. The refrigerator-freeze case according to claim 1, wherein an average value of the temperatures of the temperature sensor and the suction port temperature sensor is used. 4. The refrigerating and chilling case according to claim 1, wherein the control of the rotation speed of the drive motor of the blower is performed in conjunction with the opening and closing control of the solenoid valve.