JP3302500B2 - Control device for 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 control device for a plurality of refrigerated showcases which are connected to a common refrigerator in parallel with each other and constitute one operation system.

[0002]

2. Description of the Related Art When a large number of refrigerated showcases (hereinafter simply referred to as showcases) are installed in a store, an appropriate number, for example, eight or so, constitutes one operation system. The refrigerant circuits are usually connected in parallel to one another by a common refrigerator. In this case, the operation control of each showcase is usually performed independently by each control unit. However, the so-called defrosting operation for melting and removing frost attached to the cooler with a heater or the like is one operation.
It is common to control several times a day to start all at once at a predetermined time.Also, for the cooling operation after the completion of defrosting, it is confirmed that all defrosting of showcases in the series has been completed. In addition, control for restarting is also performed (Japanese Patent Laid-Open No.
106683).

For this purpose, conventionally, as shown in FIG. 3, control units 1a, 1a,
A common control panel 4 is installed outside the refrigerator separately from 2a, 3a..., And a defrosting start signal from a timer (defrost timer) provided inside the control panel 4 is transmitted to each showcase via an external wiring 5 and a crossover 6. Upon receiving the defrosting end signal from each showcase, the cooling operation restart signal is sent back when the defrosting of all the showcases is completed.

[0004]

Conventionally, as described above, a control panel is separately provided for synchronizing the start of the defrosting operation and the resumption of the cooling operation, and a necessary sequence circuit is incorporated in this panel. I have. However, in such a configuration in which a control panel is installed separately, wiring must be routed to and from the control panel after the showcase has been installed on site, and that work has become a heavy burden on the local construction . In addition, since the determination of the end of the conventional defrosting operation is left to each showcase, when trying to synchronize the restarting of the cooling operation, the system is dragged to the showcase with much frost and the defrosting time of the entire series becomes abnormal. It could be long.

[0005] On the other hand, with the progress of computerization of showcase control, it is not limited to turning on / off the cooler simply by detecting the temperature of the cool air outlet and starting defrosting operation at a regular time by a timer. There is a tendency to detect the condition, the temperature in the refrigerator, and the like with a large number of sensors, and to control the temperature in the refrigerator, the timing of the start of defrosting, and the like more finely. In that case, if the individual showcases in the series are to be individually and finely controlled, the scale of each control device becomes large, and the cost burden for the entire series becomes excessive. The present invention
An object of the present invention is to provide a control device for a refrigerated showcase that can perform detailed control of the entire system at a low cost while simplifying on-site wiring work. It is.

[0006]

In order to achieve the above object, the present invention relates to a plurality of refrigerated showcases connected to a common refrigerator and connected in parallel with each other to form one operation system. One of the refrigerated showcases is provided with a control management unit for centrally controlling all the refrigerated showcases in the series, and various control data from each refrigerated showcase is absorbed by the control management unit, and the control is performed. It is assumed that the control management unit integrally controls the entire system based on the data.

[0007]

In the present invention, the control data detected by the sensors of each showcase in the series is absorbed by the control management unit provided in the master unit, and the entire series is centrally integrated in the control management unit based on the control data. Control. Since the control management unit is provided in one master unit of the plurality of showcases, there is no need to provide a separate control panel, so that all control wiring can be performed at the factory stage,
No on-site wiring work is required. On the other hand, by controlling the entire series by the control management unit of the master unit, the control unit of each showcase can be reduced to the minimum necessary for inputting and outputting signals, and the scale of the entire series can be small. Moreover, since control data from each showcase can be processed in a unified manner, finer control can be performed in consideration of the overall balance as compared with the case of individual control.

[0008]

FIG. 1 is a system diagram showing an embodiment of the present invention. Showcases 1, 2, 3,... Are connected to a refrigerator (not shown) in parallel with one another to constitute one operation system.
Each of the showcases 1, 2, 3,...
are provided, and the showcase 1 is further provided with a control management unit 7 for controlling the entire system using the showcase 1 as a master unit. The control unit 1a and the control management unit are connected by an internal wiring 8, and the control units 1a, 2a, 3a... Are connected by a crossover 6.

FIG. 2 is a longitudinal sectional view illustrating the internal configuration of the showcase 1. As shown in FIG. In the drawing, two layers of inner and outer air circulation passages 10 and 11 are formed outside a refrigerating room 9 having an open front surface, and air is circulated in the direction of an arrow by the operation of fans 12 and 13 incorporated therein, respectively. An air curtain is formed on the open surface of the. In the refrigerating compartment 9, product display shelves 14 are provided in multiple stages, and the products (not shown) on the product display shelves 14 are illuminated by illuminating lamps 15 arranged as shown.
A cooler 16 connected to a refrigerator (not shown) by piping is provided in the inner passage 10, and an electromagnetic valve 17 is inserted into a refrigerant inlet pipe. A defrost heater 18 is arranged below the cooler 16.

On the other hand, an outlet sensor 19 for detecting the temperature of the blown cool air is provided at a cool air outlet in the inner passage 10, and an air temperature immediately after passing through the cooler 14 is provided on a cool air outlet side of the cooler 14. Is provided. Further, a refrigerator temperature sensor 21 for detecting a refrigerator temperature is provided on a ceiling portion of the refrigerator compartment 9. Furthermore, outside the refrigerator, a temperature sensor 22 for detecting the temperature of the outside air around the showcase and a humidity sensor 2 for detecting the humidity are provided.
3 are provided. The control unit 1a of the showcase 1 and the control management unit 7 for controlling the entire system are housed in an eave-shaped cover (canopy) 24 at the upper front of the showcase. The configuration of other showcases 2, 3,... Is the same except that the control management unit 7 is not provided.

The control units 1a, 2a, 3a... Are used for minimum parts individually required for each of the showcases 1, 2, 3,. The CPU and the memory for calculating and judging the control data from each sensor and performing the optimum internal temperature control and defrosting control for each showcase are provided in the control management unit 7. In such a configuration, the outlet sensor 19 of each showcase 1, 2, 3,.
Detection data from the cooler outlet sensor 20, the inside temperature sensor 21, the outside temperature sensor 22, the humidity sensor 23, etc., and the status signal from the ON / OFF switch (not shown) of the illuminating lamp 15, the night cover presence / absence detection switch (not shown), etc. Are all absorbed by the control management unit 7, and the control management unit 7 centrally executes the internal temperature control and the defrost control of the entire system based on all of these control data.

For example, the internal temperature control is performed as follows.
The temperature in the refrigerator is maintained in a desired range by turning on / off the cooling device 16 (opening / closing the electromagnetic valve 17) based on a comparison between a preset temperature and a temperature detected by the temperature sensor. The measurement is performed by the outlet sensor 19 instead of the internal temperature sensor 21. This is because the outside air easily enters the refrigerator through the air curtain while the store is open.
The reason 1 is that stable control cannot be performed because the output fluctuates greatly, and the outlet temperature is set lower than the desired internal temperature in preparation for the intrusion of outside air. But,
When the store is closed at night, the inside air does not fluctuate and the invasion of outside air is reduced, so that the output of the inside temperature sensor 21 is stabilized.
Therefore, during the night when the switch of the illumination lamp 15 is turned off, the inside temperature is controlled based on the temperature detected by the inside temperature sensor 21. This makes temperature control more accurate and reduces the risk of freezing of the product due to too cold. In addition, since the heat load decreases at night, the control is performed at a lower set temperature than during the day, and further, the showcase with the night cover set is controlled at a lower set temperature. The heat load of the showcase also changes depending on the outside air temperature. Therefore, the set temperature is changed depending on the data from the outside temperature sensor 22 in addition to day and night. The set temperature is lowered if the outside air temperature is high, and is raised if the outside air temperature is low.

On the other hand, defrost control is performed as follows. When frost is formed on the cooler 16, the ventilation resistance increases and the amount of circulating air decreases. However, when the amount of frost exceeds a certain level, cool air is not sufficiently supplied to the outlet due to a decrease in the amount of air.
The temperature detected by the outlet sensor 19 is considerably lower than that of the air outlet sensor 19. Therefore, if the decrease width reaches a certain value for a certain number or more of a plurality of showcases in the series, for example, five or more out of eight, if the defrosting time has come, it is assumed that the defrosting time has come and defrosting is performed at once. Start. Thus, the defrost can be started at a more appropriate timing than the regular defrost by the timer.
Defrosting is performed by turning off the cooler 16 and energizing the heater 18, but as the frost melts, the temperature detected by the cooler outlet sensor 20 gradually increases. Therefore, the defrosting is sequentially terminated from the one at which this temperature reaches a certain temperature. And whether the ratio of the number of units that have finished defrosting becomes a certain value or more,
Alternatively, even if the defrosting is not completed, when the defrosting time reaches a certain time, the cooling operation is simultaneously returned to the cooling operation. As a result, the defrosting time of the entire system is not dragged by one of the units having an abnormally long defrosting time.

The amount of frost in the cooler 16 is affected by humidity outside the refrigerator. That is, when the humidity outside the refrigerator detected by the humidity sensor 23 is high, the amount of frost increases and the number of times of defrost increases, and in such a case, it is necessary to increase the defrosting ability.
Therefore, when the outside humidity is high, the output of the heater 18 is increased, and the reverse air differential (the fan 13 of the outer passage 11 is reversed only during defrosting, and warm outside air is taken into the inner passage 10 according to the humidity). (To promote defrosting). As a result, the defrosting time is shortened, and as a result, an increase in the internal temperature can be suppressed. Conversely, when the outside humidity is low, the heater 18 is simply turned off and the heater 18 is turned off.
It is also possible to save energy by stopping the power supply (off-cycle defrost) or by performing only the reverse rotation air differential. On the other hand, if the defrosting is performed for a long time when the temperature outside the refrigerator is high, the temperature inside the refrigerator increases excessively, and there is a possibility that the product is deteriorated.
Therefore, in such a case, the defrost end temperature detected by the cooler outlet sensor 20 is lowered and defrosting is quickly increased, and the defrost end temperature is raised at night to remove the remaining frost. Since the heat load is small at night, even if the defrosting end temperature is raised, the influence on the internal temperature is small.

Although some examples of control by the control management unit 7 have been described, for example, when defrosting is started by a defrost timer, the defrosting interval (the number of times of defrosting) may be changed according to the humidity and temperature outside the refrigerator. The history of the defrosting time is stored, and the number of times of defrosting is increased only in a showcase having a particularly long defrosting time, or the time (draining time) from the end of the defrosting to the restart of the cooling operation is changed according to the temperature in the refrigerator. Various controls such as sloshing are possible. Also in this case, since the control management unit 7 that performs complicated control is installed only in the parent machine, the cost burden of the control device as a whole system is not so large.

[0016]

As described above, according to the present invention, one of a plurality of refrigerated showcases is provided with a control management unit for centrally controlling all refrigerated showcases in the series, and By absorbing the control data from the showcase in the control management unit and having the control management unit integrally control the entire sequence based on the control data, the following effects are obtained. (1) The control management unit has the following effects. Since it is placed in one of the affiliated showcases, there is no need for a separate control panel to control the entire affiliated system, simplifying on-site construction of control wiring, reducing construction costs and shortening construction schedules Can be achieved. (2) Since the control unit of each showcase in the series is kept to a minimum, and the main part is provided only in the master unit, it is necessary to configure the control unit inexpensively as a whole series while performing complicated control. Can be. (3) Since the showcases in the series can be controlled centrally,
Highly reliable control in consideration of the overall balance becomes possible.

[Brief description of the drawings]

FIG. 1 is a control system diagram showing an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a configuration of a parent machine showcase in FIG.

FIG. 3 is a control system diagram showing a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 showcase 2 showcase 3 showcase 7 control management unit 15 illuminator 16 cooler 17 solenoid valve 18 defrost heater 19 blower outlet sensor 20 cooler outlet sensor 21 internal temperature sensor 22 external temperature sensor 23 humidity sensor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F25D 11/00 A47F 3/04

Claims (1)

(57) [Claims] 1. A plurality of refrigeration showcases connected to a common refrigerator in parallel with each other to form one operation system, wherein all of the refrigeration in the system are arranged in one of the plurality of refrigeration showcases. A control management unit for centrally controlling the showcase is provided, various control data from each refrigerated showcase is absorbed by the control management unit, and the entire system is centrally controlled by the control management unit based on the control data. A control device for a refrigerated showcase.