JPH0493579A - Defrosting control device for open show case - Google Patents

Abstract

PURPOSE:To simplify a control line out of a refrigerator and further simplify a wiring work by a method wherein a defrosting timer is disposed in one open show case and a defrosting signal from the defrosting time is sent to another open show case through a bridging line between the open show cases. CONSTITUTION:A defrosting timer 13 is mounted on an open show case 1A. Electromagnetic contact devices 23 for separately controlling defrosting heaters 8A and 8B are disposed at each of open show cases 1A and 1B. Its normally- open contact point 88H is inserted into an electric power-supply circuit for the defrosting heaters 8A and 8B. A defrosting signal of the defrosting timer 13 is sent to another open show case 1B. Accordingly, a control panel can be eliminated, it is not necessary to make a respective connection between defrosting timer within the control panel and each of the defrosting thermostats 17A and 17B within the open show cases 1A and 1B and then the power supply taken into for performing an interior illumination or lighting can be utilized as the defrosting control power supply, resulting in that the control line for the defrosting control can be eliminated and then an outdoor electrical wiring can become quite simple.

Description

[Detailed description of the invention]

τIndustrial Application Field] This invention relates to an open showcase for refrigerating and displaying products.
The present invention relates to defrosting control of a cooler when a plurality of refrigerators are connected to one refrigerator to form one operating system.

[Conventional technology]

Generally, a plurality of open showcases are connected to one refrigerator to form one operation system, and FIG. 7 conceptually shows this. In other words, in the case shown, two open showcases IA
and IB are connected in parallel to one refrigerator 2, and the liquid refrigerant sent from the refrigerator 2 through the liquid pipe 3 is connected to each electromagnetic valve 4A. 4B and expansion valves 5A and 5B to the coolers 6A and 6B, where the gas is evaporated to cool the inside of the refrigerator, and then collected through the gas pipe 7 to the refrigerator 2. As time passes, frost builds up on the coolers 6A and 6B and the cooling efficiency decreases, so when a certain time is reached, a defrost timer (described later) sends a signal to stop the refrigerator 2 and energizes the defrost heaters 8A and 8B. Defrost. Figure 4 is a single line connection diagram to the warehouse of the operation system shown in Figure 7.
The 3-phase 200mm power line 10 from the power panel 9 is wired to the open showcase IA and the refrigerator 2, fIiiill
l 11 Kara single phase 200V (7) system? HIi12 is wired to open showcases IA and IB, respectively. 13 is a defrost timer, which is arranged within the control panel 11. Although not shown, a single-phase 100cm power line is connected from the power panel 9 to each open showcase IA and I as a power source for interior lighting, anti-condensation heaters, fan motors, etc.
It is wired separately to B. FIG. 3 is an internal connection diagram of a one-bun showcase. This will be explained below. In the figure, 14 is an electromagnetic contactor that turns on and off the refrigerator 2, and a thermostat for overheating prevention built into the refrigerator 2 (
Internal thermo) normally closed contact 49C2 electromagnetic contactor 1
Normally closed contact 51c of the thermal relay built into 4, refrigerator 2
The normally open contact 63H of the high pressure switch inserted into the discharge side (high pressure side) of the 1, the normally closed contact 63L of the low pressure switch also inserted into the suction side (low pressure side), and the electromagnetic switch that turns ON and OFF the defrost heaters 8A and 8B. It is connected to the single-phase 200cm control line 12 in series with the series circuit of the normally closed contact 52H of the contactor 15. The defrost timer 13 has six terminals 1 to 4, X, and H, and terminals 1 to 3 are opened and closed by a normally open contact 13a, and terminals 2 and 4 are opened and closed by a normally closed contact 13b. There is. In addition, the terminals 1 and 2 are electrically connected by a crossover wire 13C,
A self-holding coil 13d is connected between the terminals 3-X. The drive unit 13e is connected to the control line 12 via terminals 1 and N, respectively. On the other hand, the open showcases IA and IB have internal temperature control thermostats (temperature control thermostats) 16A and 16B.
, defrost control thermostat (defrost thermostat) 17A, 1
7B, alarm output thermostat (alarm thermostat) 18A
, 18B, etc. are installed respectively. A series circuit of temperature control thermostats 16A, 16B and solenoid valves 4A, 4B is OR-connected between the terminal 4 of the defrost timer 13 and one of the control lines 12; Defrost thermostats 17A and 17B are OR-connected between them. Here, in FIG. 5, 19 and 20 are the terminal boards in the control panel 11 and the open showcases IA and IB, respectively, and the appended numbers mean terminal numbers, and between the terminal boards 19 and 20 with the same terminal number. are connected by wiring. Further, between the terminal 3 of the defrost timer 13 and one of the control lines 12, an electromagnetic contactor 15 is a normally closed contact of a thermostat which is placed on a normally closed contact of the electromagnetic contactor 14. FIG. 6 is a time chart showing the operation of the control circuit shown in FIG. Now, referring to FIG. 6, the defrosting operation shown in FIG. 5 will be explained. During normal cooling operation, the electromagnetic contactor 14 is in a closed state, the normally open contact 52C1 is ONL, and the refrigerator 2 is in an operating state. At the same time, normally closed contact 52C! is 0FFL, and the electromagnetic contactor 15 is in the open state, so the defrost heater 8A
, 8B are not energized. In addition, solenoid valves 4A and 4B
is turned on and off by warm 1jlt-mo 16A and 16B.
controlled. The alarm thermometers 18A and 18B close a buzzer circuit (not shown) and issue an alarm when the temperature inside the refrigerator becomes abnormally high for some reason. Here, at a predetermined time, the drive unit 13e of the defrost timer 13 switches the normally open contact 13a to the closed state and the normally closed contact 13b to the open state, and sends out a defrost signal. At the same time, the self-holding coil 13d is energized, and each contact 13a,
13b is maintained in the above state. As a result, solenoid valve 4A
, 4B, the excitation circuit is opened and turned OFF (closed), and the refrigerant supply is stopped. At this point, refrigerator 2 is still on.
Although it is in the N state, when the refrigerant in the coolers 6A and 6B is eventually recovered, the pressure on the suction side decreases and the normally closed contact 63L of the low pressure switch turns OFF, so the electromagnetic contactor 14 is released and stops. do. As a result, the normally closed contact 52C1 becomes O.
Since the electromagnetic contactor 15 is turned on and the normally open contact 52H is turned on, the defrost heaters 8A and 8B are energized and defrosting is started. When the frost attached to the coolers 6A, 6B melts and disappears, the temperature of the coolers 6A, 6B gradually rises, but when this temperature reaches a predetermined value, the normally closed contact 17a of the defrosting thermometer 17 turns OFF.
Then, the excitation circuit of the self-holding coil 13c opens and the contact 13
a and 13b return to the illustrated state. As a result, solenoid valve 4
A, 4B are ON, defrost heaters 8A, 8B are 0FF.
L, refrigerator 2 starts operating again. In addition, in the illustrated example, in addition to defrosting by defrost heaters 8A and 8B,
A means (fan defrost) is provided that reverses the rotation of a fan (not shown) for circulating cold air inside the refrigerator to disturb the air curtain at the opening of the open showcase and introduce high-temperature outside air into the refrigerator to promote defrosting.

[Problem to be solved by the invention]

However, in such a conventional configuration, since the defrost timer 13 is installed inside the control panel 11, the fourth
As shown in the figure and FIG. 5, it is necessary to draw control lines 12 individually between the control panel 11 and the open showcases IA and IB, making the wiring complicated. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a defrosting control device for an open showcase, which simplifies the control lines outside the refrigerator and simplifies wiring work.

[Means to solve the problem]

In order to achieve the above object, the present invention has a plurality of open showcases connected to one refrigerator in parallel to form one operation system, and a defrost timer common to these open showcases. In a defrost control device for open showcases that receives defrost signals all at once, a defrost timer is installed in one of the open showcases, and the defrost signal from the defrost timer is passed through the connecting wire between the open showcases. It is configured to be sent to other open showcases.

[For use]

Conventionally, by installing a defrost timer common to multiple open showcases in one of the open showcases, the defrost timer outside the refrigerator and the defrost thermometer and temperature control thermometer inside the refrigerator are connected. This eliminates the need for control lines that were previously required.

【Example】

Hereinafter, an embodiment of the present invention in an operation system consisting of two open showcases will be described based on the drawings. Note that the same reference numerals are used for the same or corresponding parts as in the conventional example. First, FIG. 1 is a defrosting control circuit diagram corresponding to FIG. 5 of the conventional example, FIG. 1(A) is a sequence circuit diagram, and FIG. 1(B) is an internal connection diagram of an open showcase. In the figure,
Refrigerator 2 and defrost heater 8 in FIG. 1(A)
The main circuits of A and 8B are the same as the conventional ones, and their explanation will be omitted.However, the main circuits of the defrost timer 13 and its terminal board 19, which were conventionally housed therein, are different from each other (as shown in Fig. 1(B)). As shown in the figure, it is mounted in the open showcase IA. 13a is its normally open output contact. Also, the defrost heater 8A. The electromagnetic contactor 15 that controls the defrost heater 8B is the low pressure pressure switch 63.
It is directly connected in parallel to the series circuit of L and the electromagnetic contactor 14. On the other hand, as already mentioned, the open showcase IA is equipped with a defrost timer (motor timer) 13, and this defrost timer 13 is equipped with a forced switch 25 that allows the timer output to be turned on and off by manual operation. Furthermore, each open showcase IA, 1B is equipped with a defrosting controller 22A, 2 consisting of a microcomputer.
2B are provided respectively. Note that the internal configuration of the defrosting controllers 22A and 22B is not shown, and only the control contacts included therein are conceptually shown. In addition, in Figure 1, each open showcase IA
An electromagnetic contactor 23 that individually controls the defrost heaters 8A and 8B is provided in the IB, and its normally open contact 88H connects the defrost heater 8A in the open showcase LA and IB.
, 8B is inserted into the energizing circuit. Furthermore, in the case of FIG. 1, a solenoid valve 4A. 4B is placed in open showcases IA and IB,
In addition, the single-phase 100mm power supply drawn into the refrigerator as a driving power source for the interior lighting, anti-condensation heater, fan motor, etc. (24 is its terminal board, and the terminal number is the same as the terminal board 20 in the open showcases IA and IB. (wired between the two). At the same time, this 100■ power supply is connected to the defrost timer 13 and the defrost controllers 22A and 2.
It is also used as a control power source for 2B. Now, the defrosting control operation with such a configuration will be explained below with reference to the time chart of FIG. 2. During the cooling operation when the refrigerator 2 is turned on, when the defrosting time comes, the defrost timer 13 turns on the output contact 13a and sends out a defrost signal. This defrost signal is sent directly to the defrost controller 22A and also to the open showcase IA.
, IB are simultaneously sent to the defrosting controller 22B via the connecting wire 26 between the terminal boards 20 and 20. The defrosting controller 22A receives this at the photocoupler 22a,
22B is the defrost control contact [defrost thermostat] 17A, 17B
Close and open temperature control contacts (temperature control thermo) 16A16B. As a result, the electromagnetic contactor 23 is turned on and the defrost heaters 8A and 8B are energized, and at the same time the electromagnetic valves 4A and 4B are turned on.
FF is turned on, and the supply of refrigerant to the coolers 6A and 6B (FIG. 6) is stopped. The electromagnetic contactor 27 is a reversing air differential electromagnetic contactor that is turned on at the same time as the defrost heater electromagnetic contactor 23. When the normally open contact of air is introduced into the refrigerator to promote defrosting. This starts defrosting, but the solenoid valve 4A. 4B is turned off, the pressure on the suction side of the refrigerator 2 decreases, so the low pressure switch 63L is soon turned off, the electromagnetic contactor 14 is released, and the refrigerator 2 is stopped. On the other hand, as the defrosting progresses and the temperatures of the coolers 6A and 6B rise, the defrosting thermoses 17A and 17B are turned off to stop the defrosting operation. Here, the defrosting thermoses 17A and 17B operate independently of each other, and only the one whose temperature rises faster stops defrosting first. The defrost controllers 22A and 22B on the side that stopped defrosting then turn on the temperature control thermos 16A and 16B and turn on the solenoid valves 4A and 22B.
4B is turned on, but at that time, it is not turned on at the same time as the defrosting is stopped, but after the frost has melted and the water on the wet surface of the cooler 6A and 6B flows off (draining time), ONL is turned on, and the remaining water is refrozen. This is prevented. When both open showcases IA and IB finish defrosting and draining, and both solenoid valves 4A and 4B are turned on, refrigerator 2
The pressure on the suction side increases, the low-pressure cassette 63L is turned on again, the refrigerator 2 is turned on, and the cooling operation is restarted. After this, the temperature control thermostat will be set to 16 until the next defrosting time.
Each open showcase LA is activated by ON/OFF operation of A and 16B. IB internal temperature control is performed. According to the illustrated configuration, the defrost timer 13 is mounted on the open showcase IA, and the defrost signal is sent to the other open showcase IB via the connecting wire 26, so that the conventional configuration (FIG. 5) The control panel 11 in the control panel 11 is not required, and the defrost timer 13 placed in the control panel 11 and the defrost thermos 17A and 17B in each open showcase IA and IB are not required to be connected individually, and Since the power source drawn in for interior lighting etc. can be used as the defrosting control power source, the control line 12 for defrosting control between the control panel 11 or power panel 9 and the open showcases IA and 1B is unnecessary. becomes. FIG. 3 is a single-line wiring diagram showing this in comparison with FIG. 4. In FIG. 3, there is no control line 12 in FIG. 4, and the outside wiring is extremely simple. In addition, the defrost timer 13 is installed in the open showcase I.
Since it is installed in A, the excitation circuit of solenoid valves 4A and 4B, which open at the same time as the defrosting signal is sent, is shown in open showcase IA.
, IB, and accordingly, the solenoid valves 4A4B can be housed in open showcases LA and IB as shown in
It is now possible to place it within B. Solenoid valve 4A, 4B
is inserted in the middle of the refrigerant piping, but the piping work is done by the refrigeration machine engineer, and the wiring work is done by the electrician. Therefore, when the solenoid valves 4A and 4B are placed outside the refrigerator as in the past, after installing the open showcases IA and IB on-site, a refrigeration machine worker first installs the piping, and then an electrician installs the open showcases IA and IB. Wiring needed to be done, and consideration had to be given to coordination of work processes. On the other hand, if the solenoid valves 4A and 4B are placed inside the refrigerator,
The piping and wiring around the solenoid valves 4A and 4B can be completed at the factory stage, so only the refrigeration machine contractor will have to do the work on site, which will speed up the construction process. Furthermore, since the defrost timer 13 is installed inside the refrigerator, the related operations between the defrost timer 13 and the equipment inside the refrigerator can be confirmed on the spot during a test run. Conventionally, the defrost timer 13 was housed in the control panel 11 in the power room, which is located away from the open showcase installation location. I had to go around and check between 1B and 1B. Moreover, in the illustrated embodiment, since the defrost signal forced switch 25 is provided on the output side of the defrost timer 13, it is possible to repeatedly operate this switch during test runs or inspections to check the operation of various devices. Previously, the check was performed by changing the setting time of the defrost timer 13, so
There was a problem where the current time and the set time were different. Additionally, in the illustrated embodiment, defrost controllers 22A, 22
B and each defrost thermostat 17A. Since the defrosting operation stop control is performed individually in 17B,
All open showcases LA and IB as before
Compared to the case where the defrosting operation is continued uniformly until the defrosting of the product is completed, the decrease in product freshness due to an unnecessary rise in internal temperature is reduced.

【Effect of the invention】

According to this invention, by installing a defrost timer in one of a plurality of open showcases, external wiring can be simplified, construction period can be shortened and costs can be reduced, as well as test runs and inspections of open showcases. Various effects such as easier work can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a control circuit diagram showing an embodiment of the present invention.
A) is a sequence circuit diagram, Figure 1 (B) is an internal connection diagram of the open showcase, Figure 2 is a time chart showing the operation of the control circuit in Figure 1, and Figure 3 is a diagram of the control circuit in Figure 1. The corresponding external single-line wiring diagram, Fig. 4 is the external single-line wiring diagram of the conventional example, Fig. 5 is the control circuit diagram of the conventional example, Fig. 5 (A) is the sequence circuit diagram, and Fig. 5 (B) is the FIG. 6 is a time chart showing the operation of the control circuit shown in FIG. 5, and FIG. 7 is a system diagram of the open showcase in which two units constitute one system. IA, IB...open showcase, 2...refrigeration machine, 13...defrost timer, 26...crossover wire. (A) Figure Figure

Claims (1)

[Claims] 1) An open show system in which multiple open showcases are connected to one refrigerator in parallel to form one operating system, and a defrost signal is given to these open showcases all at once from a common defrost timer. In the case defrosting control device, a defrost timer is installed in one of the open showcases, and the defrost signal from this defrost timer is sent to the other open showcases through the connecting wire between the open showcases. An open showcase defrost control device characterized by: