JP2599843B2 - Heater control method for freezer and refrigerated showcase - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a refrigerator and a refrigeration showcase, in particular, a heater for controlling the operation between freezing and refrigeration in a showcase for cooling and displaying a product such as food.

[0002]

2. Description of the Related Art Such a freezing and refrigeration showcase has two compressors. During the refrigeration operation, one of the compressors is operated to maintain the temperature of the product storage in the refrigerator temperature zone. During refrigeration operation, two compressors are operated simultaneously to maintain the internal temperature in the freezing temperature range lower than the refrigeration temperature range. Defrosting removes frost adhering to the cooler for cooling the interior. A defrost heater for use during operation and a dew-proof heater for preventing dew condensation in the case are provided.

FIG. 2 shows an example of a conventional operation control circuit diagram of such a refrigerator / refrigeration showcase. In the figure, reference numeral 2 denotes a changeover switch having a contact 2a for switching to freezing operation and a contact 2b for switching to refrigeration operation. The compressor control relay 7 and the refrigeration temperature controller 3 during the refrigeration operation are connected in series to the contact 2a side, and the compressor control relay 8 and the refrigeration temperature controller 4 during the refrigeration operation are connected. The contact is connected in series to the contact 2b side, thereby forming a switching circuit between freezing and refrigeration. And
As a control circuit of the compressor in the refrigeration operation and the refrigeration operation, the contact 7a of the compressor control relay 7 during the refrigeration operation is supplied to both of the two compressor motors 14 and 15 connected in parallel.
_1, 7a ₂ are connected in series, one of the compressor contact 8a of the compressor control relay 8 during refrigerating operation in the contact 7a ₂ that connected to the motor 15 are connected in parallel.

A defrosting heater 11, a defrosting timer 9, a defrosting electromagnetic contactor 10, and a defrosting heater 13 for current 1 are connected in parallel to the refrigeration / refrigeration switching circuit and the compressor control circuit. The contact 9 of the defrost timer 9 is connected to the frost electromagnetic contactor 10.
The normally open contact 10a of the defrosting electromagnetic contactor 10 is connected to the defrost heater 13 in series. Further, a normally closed contact 10b of the defrosting electromagnetic contactor 10 is connected to the changeover switch 2 in series.

Next, the operation will be described. If the changeover switch 2 is connected to the contact 2a on the refrigeration operation side during the refrigeration operation, the compressor control relay 7 during the refrigeration operation is energized, and the contacts 7a ₁ and 7a ₂ are closed to close the two compressor motors 1
Power is supplied to the compressors 4 and 15, and two compressors are operated, and are operated in a low refrigeration temperature zone. On the other hand, to perform the refrigeration operation, if the changeover switch 2 is switched to the contact 2b on the refrigeration operation side, the compressor control relay 8 at the time of the refrigeration operation is energized, and the contact 8a is closed and only one of the compressor motors 15 is operated. Electricity is supplied, and only one compressor operates to operate in a refrigeration temperature zone higher than the freezing temperature zone.

In the freezing operation and the refrigeration operation, in order to perform defrosting due to frost formation on the cooler, when a defrosting timer 9 preset with a defrosting start time counts up, its contact 9a is closed. The defrosting electromagnetic contactor 10 is energized and its contact 10a is closed to energize the defrosting heater 13, which generates heat and melts frost adhering to the cooler. At this time, the normally closed contact 10b of the defrosting electromagnetic contactor 10 is simultaneously opened to cut off the power supply to the compressor control relays 7, 8, so that the compressor motors 14, 15 are stopped. Further, while the power supply 1 is turned on, the dew-proof heater 11 is continuously energized, so that the same amount of heat is supplied in both the freezing operation and the refrigeration operation.

[0007]

As described above, the defrosting operation is performed in exactly the same way as energizing the same defrosting heater in both the freezing operation and the refrigeration operation. In this case, the capacity of the defrosting heater is increased. Is set corresponding to the amount of frost during the freezing operation in the low temperature range, so if defrosting is performed during the freezing operation using the same defrost heater, the heating value of the defrost heater is too large and Had the disadvantage of rising. In addition, since the calorific value of the dew-proof heater is also set corresponding to the temperature in the refrigerator during operation in the freezing temperature range, the temperature in the refrigerator increases when dew-proofing is performed during refrigeration using the same heater. Resulting in.

An object of the present invention is to eliminate the disadvantages of the conventional example, and to perform defrosting and defrost prevention by different methods by changing the calorific value of the heater between the freezing operation and the refrigeration operation so as to match the respective temperature zones. In particular, it is an object of the present invention to provide a method of controlling a heater of a freezing and refrigerated showcase that prevents a rise in the temperature of a refrigerator due to defrosting and dew prevention during a refrigeration operation.

[0009]

In order to achieve the above object, the present invention has two compressors, and operates one of the compressors during a refrigeration operation and during a refrigeration operation. The two compressors are simultaneously operated to operate in a lower temperature zone than in the refrigeration operation, and in a refrigerating and refrigerated showcase including a defrost heater and a dew-proof heater, respective defrosting operations are performed in conjunction with switching between freezing and refrigeration. The gist is to change the amount of power to the defrost heater during operation and to change the amount of power to the anti-dew heater in conjunction with switching between freezing and refrigeration.

[0010]

According to the present invention, the defrosting operation during the freezing operation is performed by energizing the defrost heater, and the defrosting operation during the refrigeration operation is performed by off-cycle by setting the energizing amount to the defrost heater to zero. Therefore, the internal temperature does not increase due to the heat of the heater during the defrosting operation during the refrigeration operation. Further, in the freezing operation, for example, all of the plurality of dew-proof heaters are energized, and in the refrigeration operation, only some of the dew-proof heaters are energized to reduce the calorific value and prevent the temperature in the refrigerator from rising.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a control circuit diagram in which a method of controlling a heater of a freezing and refrigeration showcase according to the present invention is implemented. In the figure, the same components as those of the conventional example shown in FIG. The detailed description of is omitted. The basic configuration of a refrigeration / refrigeration switching circuit using two compressors and a control circuit of the compressor is basically the same as the conventional one. 2a
The defrost heater control relay 6 is connected in parallel to the compressor control relay 7 during the refrigeration operation, and the defrost heater control relay 6 is connected to the compressor control relay 8 during the refrigeration operation, which is connected in series to the contact 2 b of the changeover switch 2. Connected in parallel.

As a defrosting circuit, a defrosting timer 9, a defrosting electromagnetic contactor 10, and a defrosting heater 13 are connected in parallel to the power supply 1 as in the prior art.
Is connected in series to the defrosting electromagnetic contactor 10, and the contact 10a of the defrosting electromagnetic contactor 10 is connected in series to the defrost heater 13. In the present invention, in addition to the above configuration, the defrost heater control relay 6 are connected to the defrost heater 13 in series.

Further, as the dew-proof circuit, two dew-proof heaters 11 and 12 are provided in parallel, and one of the dew-proof heaters 12 is provided.
The normally open contact 5a of the relay 5 for controlling the dew-proof heater is connected in series.

Next, the operation will be described. As before,
During the refrigerating operation, the two compressor motors 14 and 15 are energized by the operation of the compressor control relay 7 to cool the inside of the refrigerator in the low freezing temperature zone. Electric power is supplied only to the motor 15, and the inside of the refrigerator is cooled in a refrigeration temperature zone higher than the freezing temperature zone.

In the case of defrosting during the freezing operation, when the defrost timer 9 counts up, its contact 9a is closed and the defrost electromagnetic contactor 10 is energized, and its contact 10a is closed.
At this time, the changeover switch 2 is switched to the contact 2a on the refrigeration operation side, and the relay 6 for defrost heater control is not energized. Therefore, the normally closed contact 6b is closed and the defrost heater 13 is energized. This generates heat. Therefore, defrosting during the freezing operation is performed by heat from the defrost heater 13. During this time,
The normally closed contact 10b of the defrosting electromagnetic contactor 10 opens, and the compressor motors 14 and 15 stop.

On the other hand, when defrosting during the refrigeration operation, the changeover switch 2 is switched to the contact 2b on the refrigeration side, the relay 6 for controlling the defrost heater is energized, and the normally closed contact 6b is open. The defrost heater 13 is not energized. At the same time, when the defrost timer 9 counts up and the defrost start time comes, the contact 9a is closed and the defrost electromagnetic contactor 10 is energized, the normally closed contact 10b is opened, and the compressor control relay 8 is energized. Is cut off and the compressor motor 15 stops. Therefore, defrosting during the refrigeration operation is performed only by the off cycle without supplying power to the defrost heater 13.

Next, a description will be given of the dew prevention during the refrigerating operation. During the refrigerating operation, the changeover switch 2 is switched to the contact 2a side as described above.
, The contact 5a is closed and the dew-proof heater 12 is energized. At this time, since the other dew-proof heaters 11 are connected in series to the power supply 1, the dew-proof heaters 11 are also energized, and the two dew-proof heaters 11 and 12 generate heat simultaneously, so that a large amount of heat is generated in the case. Supplied to

On the other hand, during the refrigeration operation, the changeover switch 2 is switched to the contact 2b side, so that the relay 5 for controlling the dew-proof heater is not energized, and one of the dew-proof heaters 12 does not generate heat. Only the dew-proof heater 11 generates heat. Therefore, during the refrigeration operation, the number of energized dew-prevention heaters is reduced by half compared to the refrigeration operation, and a smaller amount of heat is supplied into the case than during the refrigeration operation.

In the above-described embodiment, the defrosting method during the refrigeration operation is based on the off cycle by setting the amount of power supplied to the defrost heater 13 to 0. However, the present invention is not limited to this. Or just

[0020]

As described above, according to the method of controlling the heater of the freezing and refrigeration showcase of the present invention, the amount of power to the defrost heater and the dew-proof heater is changed between the freezing operation and the refrigeration operation.
A suitable amount of heat can be supplied to each of the freezing temperature zone and the refrigeration temperature zone. In particular, it is possible to prevent overheating of the heater and increase in the temperature of the refrigerator during the refrigeration operation, and also to save energy.

[Brief description of the drawings]

FIG. 1 is an operation control circuit diagram in which a heater control method for a refrigerator-freezer showcase of the present invention is implemented.

FIG. 2 is an operation control circuit diagram of a conventional method for controlling a heater of a refrigerator-freezer showcase.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Power supply 2 ... Changeover switch 2a ... Contact 2b ... Contact 3 ... Refrigeration temperature controller 4 ... Refrigeration temperature controller 5 ... Dew-proof heater control relay 5a ... Contact 6 ... Defrost heater control 6b ... Normally closed contacts 7 ... compressor control relay 7a ₁ ... contacts 7a ₂ ... contact 8 ... compressor control relay 8a ... contact 9 ... defrost timer 9a ... contact 10 ... defrost electromagnetic contactor 10a ... normally open contact 10b ... normally closed contact 11 ... dew-proof heater 12 ... dew-proof heater 13 ... defrost heater 14 ... compressor motor 15 ... compressor motor

Claims (1)

(57) [Claims] 1. A compressor having two compressors, wherein one of the compressors is operated during a refrigeration operation, and the two compressors are simultaneously operated during a refrigeration operation so that the compressor is operated at a lower temperature than during the refrigeration operation. Operating in a low temperature zone, in a refrigerated showcase including a defrost heater and a defrost prevention heater, the amount of power to the defrost heater during each defrost operation is changed in conjunction with switching between freezing and refrigeration, and A method for controlling the amount of electricity supplied to a dew-proof heater in conjunction with switching between freezing and refrigeration.