JP3071027B2 - Defrosting control method 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 method for controlling defrosting of a refrigerating and refrigerated showcase of a refrigerator type.

[0002]

2. Description of the Related Art As is well known, a refrigerated showcase is provided with a refrigerating device including a compressor, a condenser, a cooler and the like, and the refrigerating device keeps the temperature in a product storage at a constant level. However, there is a refrigerator-separated type in which only a cooler is provided in a showcase body and a compressor or the like is provided in a machine room or the like remote from a place where the showcase is installed.

[0003] In this type of refrigerator-freezer refrigerated showcase, for example, when a large number of showcases are installed in a supermarket or the like, showcases having the same operating conditions depending on the type of goods to be stored are installed in a machine room. Refrigerators such as compressors are commonly used by a plurality of showcases, and the defrosting operation of the coolers provided in each showcase is performed simultaneously.

Conventionally, the wiring structure in this case is, for example, for a cooling operation, each showcase and a refrigerator are connected by a power line, and for a defrosting operation, a control of a machine room is performed. A defrost timer is provided for each showcase on the panel, and a defrost heater provided for each showcase is connected to each defrost timer. Then, the refrigerator is turned on / off to perform the cooling operation, and all the defrost heaters are energized to perform the defrost operation simultaneously in all the showcases.

[0005] In a refrigerated showcase employing such an operation method, a large current flows at a time when the defrost heater and the refrigerator are energized at the same time. A relay or the like is provided in the defrost circuit to which the defrost heater is connected.

[0006]

As described above, conventionally, each showcase is individually connected to the refrigerator and the respective defrost timers, so that not only the number of wirings is increased but also the simultaneous energization is prevented. In addition, the circuit configuration became complicated, wiring man-hours and costs were increased, and advanced wiring technology was required.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned disadvantages of the prior art, wherein a single refrigerator is shared by a plurality of freezing and refrigerated showcases, and a plurality of freezing and refrigerated showcases are simultaneously defrosted. An object of the present invention is to provide a method for controlling defrosting of a refrigerated showcase, which has a simple wiring structure and can reliably prevent simultaneous energization of a refrigerator and a defrost heater.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a refrigeration system in which a plurality of coolers installed in a plurality of showcases are connected to a single refrigerator to simultaneously defrost these coolers. In the method for controlling defrosting of a refrigerated showcase, a defrosting control circuit is provided for each freezing and refrigerated showcase and a refrigerator, and both defrosting control circuits are connected by a serial transmission line. After a defrost start command is transmitted to the defrost control circuit on the refrigerated showcase side via a serial transmission line, each refrigerated showcase receives the defrost start command, stops the operation of the cooler, and executes a defrost start command. The defrost control circuit on the freezing and refrigeration showcase side transmits the signal to the defrosting control circuit on the refrigerator side via a serial transmission line, and after receiving this response, the defrosting control circuit on the refrigerator side Side defrost control circuit When the low pressure cut signal is input, it is determined that the refrigerator is turned off, and the defrost heater of the defrost heater is transmitted from the defrost control circuit on the refrigerator side to the defrost control circuit of each freezing and refrigeration showcase through a serial transmission line. When the defrost control circuit of all the freezing and refrigeration showcases detects the completion of defrosting and reports via a serial transmission line that the defrosting heater has been turned off while outputting the energization start command, each freezing and refrigeration showcase And outputting a cooling start command through a serial transmission line.

[0009]

According to the present invention, since the defrosting control circuit of the refrigerator installed in the machine room and each of the freezing and refrigeration showcases are only connected to each other by the serial transmission line, the number of wirings is small.
The defrost start command from the defrost control circuit on the refrigerator side to the defrost control circuit on the freezing and refrigeration showcase side, and the low pressure cut signal are input to the defrost control circuit on the refrigerator side to turn off the refrigerator. After the confirmation, a command to start energizing the defrost heater later is output, and the defrost control circuits of all the freezing and refrigeration showcases detect the end of defrost and turn off the defrost heater. Since the cooling start command is output, simultaneous energization to the refrigerator and the defrost heater is reliably prevented only by the response of the signal using the serial transmission line.

[0010]

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 block diagram for implementing a method for controlling defrosting of a refrigerator-freezer showcase according to the present invention. In FIG. 1, reference numeral 5 denotes a control device of a refrigerator installed in a machine room or the like, and 11 denotes a plurality of freezers installed in a store. 2 shows a showcase control device provided for each refrigerated showcase.

The control device 5 of the refrigerator includes a defrost control circuit 3 for instructing the timing of defrosting of each showcase, and a transmission connected to the defrost control circuit 3 for inputting and outputting signals to and from the showcase. A defrost timer 1 for counting a defrost start time and a low-pressure cut detector 2 for detecting a stop of the refrigerator are connected to an input side of the defrost control circuit 3.

The control device 11 of the showcase comprises a defrost control circuit 9 and a transmission circuit 10 for inputting and outputting signals to and from the control device 5 of the refrigerator. An electromagnetic valve 7 for turning on and off the supply, an electromagnetic switch 8 for turning on and off the defrost heater, and a defrost end detector 6 for detecting the end of defrost are connected to the input side of the defrost control circuit 9.

Then, a plurality of transmission circuits 10 on the showcase side and a transmission circuit 4 on the refrigerator side are connected by a serial transmission line 12.

Next, the operation will be described with reference to the flowcharts of FIGS. FIG. 2 is a flowchart showing the operation of the defrost control circuit 3, and FIG. 3 is a flowchart showing the operation of the defrost control circuit 9. While the refrigerator operates and the cooling operation of the plurality of showcases is performed, the defrosting is performed. The frost timer 1 counts the defrost start time, and the count value is determined by the defrost control circuit 3.
[Step (A)], and when the defrost start time set in the defrost control circuit 3 is reached [Step (B)],
A defrosting start command is transmitted from the transmission circuit 4 to the transmission circuits 10 of the control devices 11 of all showcases via the serial transmission line 12 [step (c)].

The transmission circuit 10 of the control device 11 on the showcase side receives this defrosting start command (steps (ヲ) and (W) in FIG. 3) and outputs it from the defrosting control circuit 9 to the solenoid valve 7. This is turned off [step (f)], and at the same time, the operation of the cooler is stopped, and at the same time, a response indicating that the defrost start command has been received is output from the transmission circuit 10 to the transmission circuit 4 via the serial transmission line 12 [step (step (f)). G)).

The control device 5 on the refrigerator side receives this response [step (d, e)], and determines whether a low pressure cut signal is input from the low pressure cut detector 2 to the defrost control circuit 3 or not. [Step (f)], if a low pressure cut signal is input [Step (g)], it is determined that the refrigerator is turned off, and a command to start energization to the defrost heater is transmitted from the transmission circuit 4 to all of them. Output to the transmission circuit 10 of the control device 11 of the showcase [Step (h)].

The transmission circuit 10 on the showcase side receives this command [Step (T, T)] and outputs it from the defrost control circuit 9 to the electromagnetic switch 8 to turn on the power to the defrost heater [Step (S)]. ].

When the end of the defrosting is detected by the output from the defrosting end detector 6 to the defrosting control circuit 9 (step (T)), the output from the defrosting control circuit 9 is used as the defrosting heater. Is turned off [step (n)], and the completion of defrosting is output from the transmission circuit 10 to the transmission circuit 4 of the control device 5 of the refrigerator [step (a)].

In the other showcases, the same operation is performed when the defrosting start time set in the defrosting control circuit 3 comes, and the end of the defrosting is transmitted from the transmission circuit 10 to the transmission circuit of the control device 5 of the refrigerator. 4 is output.

The defrost control circuit 3 of the control device 5 receives the notification of the completion of the defrost [step (re)], and informs all the showcases that the defrost has been completed and that the defrost has been completed in all the showcases. After confirming [Step (N)], the transfer circuit 4 outputs a cooling operation start command to all showcases via the transmission line 12 [Step (L)]. The showcase side receives this command [Step (M, C)], turns on the solenoid valve 7 with the output of the defrost control circuit 9 [Step (No)], supplies the refrigerant to the cooler, and starts the cooling operation. I do.

[0021]

As described above, according to the method for controlling defrosting of a refrigerated showcase of the present invention, one refrigerator is shared by a plurality of refrigerated showcases, and a plurality of refrigerated showcases are removed. When performing the frost operation simultaneously, the refrigerator side and the showcase side were connected to each other with a serial transmission line,
The on / off of the refrigerator and the on / off of the defrost heater can be controlled by the response of the signal via the transmission line, so that not only the wiring structure for control can be simplified, but also the refrigerator and the defroster can be controlled with this simple wiring structure. Simultaneous energization to the frost heater can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a control block diagram in which a method for controlling defrosting of a refrigerator-freezer showcase according to the present invention is implemented.

FIG. 2 is a flowchart showing an operation on a refrigerator side of a method for controlling defrosting of a refrigerator-freezer showcase of the present invention.

FIG. 3 is a flowchart showing an operation on the showcase side of the method for controlling defrosting of the freezing and refrigeration showcase of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Defrost timer 2 ... Low pressure cut detector 3 ... Defrost control circuit 4 ... Transmission circuit 5 ... Control device 6 ... Defrost end detector 7 ... Solenoid valve 8 ... Electromagnetic switch 9 ... Defrost control circuit 10 ... Transmission Circuit 11 ... Control device 12 ... Serial transmission line

Continuation of front page (58) Fields investigated (Int. Cl. ⁷ , DB name) F25D 11/00-13/00 F25D 21/08 F25D 23/00 301 A47F 3/04

Claims (1)

(57) [Claims] 1. A method for controlling defrosting of a refrigerated showcase in which a plurality of coolers installed in a plurality of showcases are connected to a single refrigerator and defrosting of the coolers is performed simultaneously. A defrost control circuit is provided for the case and the refrigerator, and both defrost control circuits are connected by a serial transmission line, and the defrost control circuit on the refrigerator side is connected to the defrost control circuit on the refrigeration showcase by a serial transmission line. After the defrosting start command is transmitted, each freeze / refrigeration showcase receives the defrosting start command, stops the operation of the cooler, and informs the freezing / refrigeration showcase that the defrosting start command has been received. After transmitting from the circuit to the defrost control circuit on the refrigerator side via a serial transmission line, the defrost control circuit on the refrigerator side receives this response,
When a low-pressure cut signal is input to the defrost control circuit on the refrigerator side, it is determined that the refrigerator is turned off, and the defrost control circuit on the refrigerator side defrosts the defrost control circuit of each freezing and refrigeration showcase. To the defrost heater through the serial transmission line, and the defrost control circuits of all the freezing and refrigeration showcases detect the end of defrost and report through the serial transmission line that the defrost heater has been turned off. Wherein a cooling start command is output to each freezing and refrigerated showcase via a serial transmission line when the refrigerated showcase is defrosted.