JPH04347478A - Control device for compressor for refrigerating and cold-storage showcase - Google Patents

Abstract

PURPOSE:To permit operation in a desired temperature zone by only pushing a changeover switch and make operations, such as temperature setting and the like, unnecessary when either one set or two sets among two sets of cooling devices are operated in different temperature zones to effect cooling operation. CONSTITUTION:A plurality of changeover switches 11a, 11b, 11c, which are connected to a plurality of temperature regulators 2a, 2b, 2c having different temperature settings of cold storage or refrigerating respectively, are connected to the driving circuits of compressors 6a, 6b for a cooling device while the compressors 6a, 6b to be driven are selected by selecting the changeover switches 11a, 11b, 11c.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator/freezer showcase for displaying products such as foods in a cooled state, and more particularly to a compressor control device for a cooling device.

0002

2. Description of the Related Art As shown in FIGS. 6 and 7, for example, a refrigerated freezer showcase has a showcase body 1 with an opening at the top, which is made up of heat insulating walls, and is connected to a cold air circulation duct 17 and a product storage 18 using a duct plate. A fan 8 and coolers 5a, 5b are installed in the cold air circulation duct 17, and condensers 4a, 4b are installed in the machine room 9 formed below the showcase main body 1.
, condenser fans 7a, 7b, and compressors 6a, 6b are provided. A variable temperature controller 2 for setting the cooling temperature inside the refrigerator is installed on the front side of the machine room cover 9a that covers the front opening of the machine room 9.
1, and a changeover switch 22 for switching between refrigeration operation and freezing operation, and a temperature sensing part 21a of the variable temperature regulator 21.
is installed near the air intake port of the cold air circulation duct 17.

FIG. 8 shows the configuration of the refrigeration cycle of the cooling device, which includes a compressor 6a (6b), a condenser 4a (4b),
The expansion valve 10a (10b) and the cooler 5a (5b) are sequentially connected by refrigerant piping.

FIG. 9 shows a compressor motor 19a of a compressor 6a,
A control circuit for a compressor motor 19b of a compressor 6b is shown, in which a variable temperature regulator 21, a contact 12a of a defrosting timer 12, and a relay 14 are connected in series, and a changeover switch 2 is connected to the relay 14.
The series connection circuit of the second contact 22a and the relay 15 is connected in parallel, and the series connection circuit of the variable temperature regulator 21 and the defrost timer 12 are connected in parallel to the power supply. Also,
The contact 14a of the relay 14 is connected in series to the compressor motor 19a to which the fan motor 20a of the condenser fan 7a is connected in parallel, and the contact 14a of the relay 14 is connected in series to the compressor motor 19b to which the fan motor 20b of the condenser fan 7b is connected in parallel. The contacts 15a are connected in series, and the compressor motors 19a and 19b are connected in parallel to the power supply. These control circuits are housed, for example, in a control box 3 attached to the back surface of the machine room cover 9a.

Next, the operation will be explained with reference to FIGS. 10 and 11. When performing refrigeration operation, the variable temperature controller 21 is operated to set the refrigeration temperature T1 as the cooling temperature inside the refrigerator, and the changeover switch 22 is turned off. As a result, the relay 15 is not energized, the compressor motor 19b is not energized, only one compressor motor 19a is energized, and only one compressor 6a is operated. When the compressor 6a operates,
The high temperature and high pressure refrigerant compressed here is cooled by the condenser fan 7a in the condenser 4a, and becomes low pressure in the expansion valve 10a.
It becomes a low-temperature, low-pressure refrigerant in the cooler 5a, exchanges heat with the surrounding air, and cools the surrounding air. This cooled air is sent into the product storage 18 by the fan 8 to cool the inside of the storage.

[0006] In this way, the inside of the refrigerator is cooled, and the temperature sensing part 2
When the temperature inside the refrigerator detected by 1a decreases from the normal temperature point A at the start of operation and further drops below the set temperature T1 and reaches point B, the variable temperature regulator 21 is turned off and the power to the relay 14 is cut off. The contact 14a opens and the compressor motor 19a
The power to the compressor 6a is cut off, and the compressor 6a is stopped. Compressor 6a
When the refrigerator stops and cooling operation stops, the temperature inside the refrigerator increases,
When the temperature reaches point C, which is higher than the set temperature T1, the variable temperature regulator 21 is turned on again, and the compressor 6a resumes operation. By repeating this on/off cycle, the temperature inside the refrigerator is set to the set temperature T.
Keep it close to 1.

Next, when performing a freezing operation at a temperature lower than that of the refrigeration operation, the variable temperature controller 21 changes the cooling temperature inside the refrigerator to a set temperature T3 for freezing, which is lower than the set temperature T1 during the refrigeration operation. setting, and turn on the changeover switch 22. As a result, the compressor motor 19b is also energized, the two compressors 6a and 6b are operated at the same time, and the cooling temperature inside the refrigerator is reduced. When the internal temperature detected by the temperature sensor 21a falls further below the set temperature T3 (point D), the variable temperature regulator 21 is turned off and the two compressors 6a and 6b are stopped. When the temperature inside the refrigerator rises and reaches point E, which is higher than the set temperature T3, the variable temperature controller 21 is turned on again, and the two compressors 6a and 6b are turned on again to perform cooling operation and set temperature T3. The internal temperature is maintained close to temperature T3.

For example, during refrigeration operation, the defrost timer 1
When the defrosting start time preset in 2 arrives (point F),
The contact 12a opens and the power to the relay 14 is cut off,
The compressor 6a is stopped and the cooling operation is stopped. When the internal temperature rises to point G, it is determined that defrosting has ended, the contact 12a closes again, and the compressor 6a resumes operation.

[0009]

[Problems to be Solved by the Invention] As described above, in conventional refrigeration/refrigeration showcases, switching between refrigerating operation and freezing operation requires changing the set temperature using a variable temperature controller and switching the changeover switch. This required two operations, which was troublesome.

An object of the present invention is to solve the above-mentioned disadvantages of the conventional example, and to provide a refrigeration system that can automatically control operation at a cooling temperature between refrigeration or freezing, or between refrigeration and freezing, with a simple operation of pressing one switch. An object of the present invention is to provide a compressor control device for a showcase.

[0011]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides two cooling devices, one of which is operated during refrigeration operation, and one of the cooling devices is operated during refrigeration operation. In a refrigerator/refrigeration showcase that operates two cooling devices at the same time, a plurality of changeover switches each connected to a plurality of temperature controllers each having a different temperature range for refrigeration or freezing are installed in the drive circuit of the compressor of the cooling device. The gist of the system is to select the compressor to be driven by selecting a selector switch.

0012

[Operation] According to the present invention, by selecting and pressing one of the changeover switches connected to a temperature controller set to a temperature range of refrigeration, freezing, or an intermediate temperature range, the changeover switch can be pressed. The output from the compressor operates one compressor, another compressor, or two compressors.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a circuit diagram showing one embodiment of the compressor control device for a freezer/refrigerator showcase of the present invention, FIG. 2 is a front view of a freezer/refrigerator showcase equipped with the device of the present invention, and FIG. This is a vertical cross-sectional side view of the frozen/refrigerated showcase, and the same components as those of the conventional example shown in FIGS. 7 to 9 are given the same reference numerals. The basic configuration of the frozen/refrigerated showcase is the same as the conventional example already explained with reference to FIGS. 6 and 7, so a detailed explanation will be omitted here. is divided into a cold air circulation duct 17 and a product storage 18 by a duct plate, and coolers 5a, 5b and a fan 8 are installed in the cold air circulation duct 17.
In the lower machine room 9, compressors 6a, 6b, condensers 4a, 4b, and condenser fans 7a, 7b are installed.

The refrigeration cycle of the cooling device is the same as that shown in FIG.
b and cooler 5b are connected by refrigerant piping to form a refrigeration cycle.

[0015] The present invention provides a freezer/refrigerator showcase in which two cooling devices are installed as described above, in which the temperature controller 2a is set to the refrigeration set temperature T1 as the cooling temperature inside the refrigerator, and the freezing set temperature T3 is set to the temperature controller 2a. A temperature regulator 2c is provided, and a temperature regulator 2b is provided with a preset temperature T2 for refrigeration between the preset temperatures T1 and T3. It was provided near the air suction port of the circulation duct 17. In addition, there are three
Continuous changeover switches 11a, 11b, and 11c are provided on the front surface of the machine room cover 9a, etc.

As shown in FIG. 1, as a control circuit for compressor motors 19a, 19b of compressors 6a, 6b, a contact 12a of a defrost timer 12 is connected in series to changeover switches 11a, 11b, 11c which are connected in parallel. , selector switch 11
A relay 16 for controlling one compressor is connected in series to a. A temperature controller 2b and a relay 14 for controlling the compressor motor 19a are connected in series to the changeover switch 11b, and a temperature controller 2c, a normally closed contact 16a of the relay 16, and a relay 14 for controlling the compressor motor 19b are connected to the changeover switch 11c. A control relay 15 is connected in series, and a delay timer 13 is connected in parallel to the relay 15, and the relay 1 for controlling the compressor motor 19a is connected via the contact 13a of the delay timer 13.
A changeover switch 11c is connected in series to 4. In addition, the temperature controller 2a and the compressor 1 are connected to the contact 12a of the defrost timer 12.
The normally open contact 16b of the relay 16 for controlling the stand and the relay 15 for controlling the compressor motor 19b are connected in series. Relays 14 are connected to compressor motors 19a and 19b to which fan motors 20a and 20b are connected in parallel, respectively.
, 15 are connected in series, and the compressor motor 19a and the compressor motor 19b are connected in parallel to the power supply.

Next, the operation will be explained with reference to FIGS. 4 and 5. To perform the refrigeration operation at the set temperature T1 set in the temperature controller 2a, when the changeover switch 11a is pressed, the relay 16 is energized, its normally closed contact 16a opens, and its normally open contact 16b closes. As a result, relay 1
5 is energized, its contact 15a closes, and the compressor motor 1
9b is energized, and the compressor 6b is operated. At the same time, the fan 8 is also energized, and the air cooled by the cooler 5b is sent into the refrigerator for cooling. When the temperature inside the refrigerator detected by the temperature controller 2a falls below the set temperature T1 (point H), the compressor 6b stops, and then the temperature inside the refrigerator falls below the set temperature T1.
When the temperature rises above (point I), the compressor 6b is turned on again and the cooling operation is resumed. By repeating such on/off operations, the temperature inside the refrigerator is maintained close to the set temperature T1.

Next, the set temperature T set on the temperature controller 2c
3, when the changeover switch 11c is pressed, the relay 15 is energized, its contact 15a is closed, the compressor motor 19b is energized, and the compressor 6b is turned on. At the same time, the delay timer 13 is also energized, and when it counts up, its contact 13a closes and the relay 14 is energized, the contact 14a is closed and the compressor motor 19a is energized, and the other compressor 6a is also activated slightly later than the compressor 6b. Turn on, compressor 6
Simultaneous cooling operation of the two units a and 6b starts. During such refrigeration operation, when the temperature inside the refrigerator falls below the set temperature T3, the compressors 6a and 6b are turned off (point J), when the temperature rises above the set temperature T3, the compressor 6b is turned on, and a little later than this, the compressors 6a and 6b are turned off. 6a is turned on (point K) and this process is repeated.

To perform the cooling operation at the set temperature T2 set on the temperature controller 2b between the set temperatures T1 and T3, press the changeover switch 11b, and the temperature controller 2b
The relay 14 is energized via the relay 14, the contact 14a is closed, the compressor motor 19a is energized, and only the compressor 6a is turned on. Then, with the set temperature T2 as the boundary, the upper limit value L point,
The compressor 6a is repeatedly turned on and off between the lower limit value M point and maintains the internal temperature near the set temperature T2.

During this cooling operation, when the defrosting start time set in the defrosting timer 12 comes and the contact 12a opens, all electricity to the cooling circuit is cut off, the cooling device is stopped, and the defrosting operation is performed. As defrosting progresses and the internal temperature rises and reaches point N, the contact 12a of the defrosting timer 12 is reset and the cooling operation is resumed.

[0021]

[Effects of the Invention] As described above, the compressor control device for a refrigerator/freezer showcase of the present invention allows cooling operations to be performed in different temperature ranges such as refrigeration, freezing, and between them by simply pressing a changeover switch. Since the operation is automatically switched to the temperature range of 1, there is no need to perform temperature setting operations each time, and the switching operation can be performed easily.

[Brief explanation of the drawing]

FIG. 1 is a control circuit showing one embodiment of a compressor control device for a refrigerated showcase of the present invention.

[Fig. 2] One of the refrigerator/freezer showcases equipped with the device of the present invention
It is a front view showing an example.

[Fig. 3] One of the refrigerator/freezer showcases equipped with the device of the present invention
It is a longitudinal side view which shows an example.

FIG. 4 is a temperature characteristic diagram of the device of the present invention.

FIG. 5 is a time chart of operations performed by the device of the present invention.

FIG. 6 is a front view showing a conventional example of a frozen/refrigerated showcase.

FIG. 7 is a longitudinal side view showing a conventional example of a freezer/refrigerator showcase.

FIG. 8 is an explanatory diagram of the refrigeration cycle of the frozen/refrigerated showcase.

FIG. 9 is a circuit diagram of compressor control showing a conventional example.

FIG. 10 is a temperature characteristic diagram according to a conventional example.

FIG. 11 is a time chart of operations according to a conventional example.

[Explanation of symbols]

1...Showcase body 2a, 2b, 2c...Temperature controller 3...Control box 4a, 4b...Condenser 5a, 5b...Cooler 6a, 6b...Compressor 7a, 7b...Condenser fan 8...Fan 9...Machine room 9a... Machine room cover 10a, 10b... Expansion valve 11a, 11b, 11c... Changeover switch 12... Defrost timer 12a... Contact 13... Delay timer 13a... Contact 14... Relay 14a... Contact 15... Relay 15a... Contact 16... Relay 16a , 16b...Contact 17...Cold air circulation duct 18...Product storage 19a, 19b...Compressor motor 20a, 20b...Fan motor 21...Variable temperature controller 21a...Temperature sensing section 22...Selector switch 22a...Contact

Claims (1)

[Claims] Claim 1: In a freezer/refrigeration showcase that is provided with two cooling devices, in which one of the cooling devices is operated during refrigeration operation, and the two cooling devices are operated simultaneously during refrigeration operation. , a plurality of changeover switches each connected to a plurality of temperature controllers each having a different temperature range for refrigeration or freezing are connected to the drive circuit of the compressor of the cooling system, and the compressor is driven by the selection of the changeover switch. A compressor control device for a refrigerated refrigerator showcase.