JPH055429Y2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to a low-temperature case that uses two types of power sources, such as a 200V three-phase AC power supply and a 100V single-phase AC power supply, as power supplies.

(B) Conventional technology Conventionally, this type of low-temperature storage case has a storage chamber that is wide open upwardly or forwardly, and has a storage chamber that is wide open upwards or forwardly, in order to facilitate selective removal by the purchaser or storage of the product by the user. The cold air cooled by the evaporator included in the cycle is accelerated by a blower, and an air curtain is formed at the opening to prevent warm air from entering from outside, while the cold air is forced to circulate inside the storage room for cooling. It is becoming. The handrail portion at the edge of the storage chamber opening of the show case is exposed to the outside air and is further cooled by the circulating cold air, so moisture in the outside air is likely to condense, and therefore an anti-condensation heater is provided. Further, lighting equipment such as a fluorescent light is installed in the storage room as necessary.

(c) Problems that the invention aims to solve The electric compressor that constitutes the refrigeration cycle of such a low-temperature show case is installed in a machine room outside the storage room, and the storage room is open, so it has a relatively high output. Therefore, the power supply is usually three-phase AC 200V. However, the blower
For items installed inside the storage room, such as anti-condensation heaters and fluorescent lights, a single-phase AC 100V power supply is usually used to prevent accidents such as electric shock to the purchaser. That is, two types of power sources are used, as shown in, for example, Japanese Utility Model Publication No. 52-37895.

In order to prevent condensation from occurring due to the dew-proof heater not generating heat, the bulletin states that if only the single-phase AC 100V power supply is out of power, the electric circuit between the electric compressor and the three-phase AC power supply is cut off, and the electric compressor It is configured to stop the machine. In addition, in this case, a special operation indicator lamp is installed for the anti-condensation heater so that it is turned off in the event of a power outage, which raises the problem of rising costs due to the increase in the number of operation indicator lamps. There was also a problem in which people were not aware of power outages for long periods of time.

(d) Means for solving the problems The present invention has been made to solve the above problems, and the structure of the present invention will be explained below with reference to examples.

A compressor drive motor 3 included in the refrigeration cycle of the show case is connected to a first power source 1 of three-phase AC 200V. The first power supply 1 has an abnormal temperature detector 13 that detects the temperature of the condenser of the refrigeration cycle and closes the contact when the temperature reaches an abnormally high temperature, and an alarm buzzer BZ, with the terminal a of the changeover switch 9B and the common interposed between them. At least it's connected. Terminal b of selector switch 9B
is connected between the alarm BZ and the first power supply 1. On the other hand, the dew-proof heater 19 is connected to the second power supply 15 of single-phase AC 100V.
Furthermore, a relay coil 9 is connected to the second power supply 15.
Connect. The relay coil 9 closes the changeover switch 9B to terminal a when it is energized, and closes the switch 9B to terminal b when it is de-energized.
Close to.

(e) Effect: According to the present invention, a power outage of the second power source can be notified by using the abnormal temperature alarm of the condenser of the refrigeration cycle, which is normally used in low-temperature housings.

(f) Examples Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an electrical circuit diagram of the present invention. 1 is the first
The power supply is a three-phase AC 200V power supply, and its R
The phase is connected to the electric compressor drive motor 3 via the normally open contact 2A of the relay coil 2. Also, the S phase is connected to the motor 3, and the T phase is connected to the relay coil 2.
It is connected to the motor 3 via the normally open contact 2B.
A relay coil 4 is connected between the R phase and T phase of the first power supply 1.
a normally open contact 4A, a thermostat 5 that senses the temperature inside the storage chamber of the show case, and a relay coil 2.
are connected in series. Relay coil 4 connects terminal a of defrost timer TM selector switch 6 and first power supply 1.
is connected between the T-phases of the L ₁ is the defrost indicator lamp,
It constitutes a parallel circuit with the relay coil 8, and is connected between the terminal b of the changeover switch 6 and the T phase. The common terminal of the changeover switch 6 is connected to the R phase via the normally open contact 9A of the relay coil 9. Defrost TimerTM is
A parallel circuit is formed with the blower drive motor 10 for cooling the condenser of the refrigeration cycle, and the R
Connected between phase and T phase. Reference numeral 11 denotes a defrosting heater for the evaporator of the refrigeration cycle (not shown), and the R phase and T Connected between phases.

Reference numeral 13 designates an abnormal temperature detector as an abnormality detector for detecting the temperature of the condenser of the refrigeration cycle, and is connected in series with the abnormality display lamp _L2 . BZ is an alarm buzzer as an alarm device, and is connected in parallel to the abnormality indicator lamp _L2 via the common of the changeover switch 9B of the relay coil 9 and the first terminal a. Further, the second terminal b of the changeover switch 9B is connected between the alarm BZ and the R phase of the first power supply 1. The changeover switch 9B is closed to the terminal b when the relay coil 9 is energized, and closed to the terminal a when the relay coil 9 is not energized.

Next, 15 is a single-phase AC 100V power supply as a second power supply, and the second power supply 15 is connected to a relay coil 9, a fluorescent lamp 17 for lighting the storage room, and a blower for circulating cold air through an operation switch 16. A motor 18 and an anti-dew heater 19 for preventing dew condensation on the handrail at the edge of the storage chamber opening of the show case are connected in parallel. The electric compressor drive motor 3 requires a large current when starting up and is usually installed in a machine room outside the storage room, so it is connected to the first power source 1. The heater 19 and the blower drive motor 18 are connected to the second power source 15 in consideration of electric shock accidents for product purchasers. In addition, the anti-frost heater 11 is installed in the evaporator of the refrigeration cycle, but since a relatively large current flows during defrosting, if it is connected to the second power supply 15, the voltage drop may cause the anti-defrost heater 19 to generate heat. The fluorescent lamp 17 is connected to the first power source 1 because the fluorescent lamp 17 has a lighting failure.

Next, the operation will be explained. Assuming that the first power source 1 and the second power source 15 are normal, when the operation switch 16 is closed, the fluorescent light 17 lights up and the blower drive motor 18 is operated to circulate air inside the storage room and to circulate air through the opening. An air curtain is formed to suppress the entry of outside air, and heat is generated by the dew prevention heater 19.
Also, since the relay coil 9 is also energized, the contact 9A
is closed, and the changeover switch 9B is closed to terminal a.
Also, since defrosting is not currently in progress, the changeover switch 6 is closed to the terminal a, and the relay coil 4 is energized and the contact 4A is closed. Also, at this time, the temperature in the storage room is high, so the thermostat 5 is closed (thermostat 5 opens its contacts when the temperature is -2°C, and closes at +2°C).
℃ and close the contacts. ), therefore, the relay coil 2 is energized and the contacts 2A and 2B are closed, the electric compressor drive motor 3 is started, and the cooling operation of the storage room is started. The cold air cooled by the evaporator is circulated into the storage chamber by the operation of the blower drive motor 18. This cooling lowers the storage room temperature by -2
When the temperature drops to .degree. C., the thermostat 5 opens to de-energize the relay coil 2, and the contacts 2A and 2B open to stop the motor 3. Even if the motor 3 is stopped and the refrigerant circulation in the refrigeration cycle is stopped, the motor 18 is continuously operated to form an air curtain. After that, repeat this process to bring the inside of the storage room to an average of 0°C.

During this time, the defrost timer TM performs integration operation,
Close the changeover switch 6 to terminal b for 30 minutes once within 8 hours, open the contact 4a to stop the motor 3, energize the relay coil 8 and close the contact 8A,
The defrosting heater 11 is energized to start defrosting the evaporator. When defrosting progresses and the temperature of the evaporator at the defrosting end temperature sensor 12 rises to +10°C, the contact is opened and defrosting ends. During this defrosting operation, the motor 18 is operated continuously to form an air curtain, but since the heat generated by the defrosting heater 11 is used to melt the frost, it has almost no effect on the storage room. I won't give it. Further, the calorific value of the defrosting heater 11 is set to a capacity sufficient to defrost the air while cold air is being circulated to the evaporator. On the other hand, if the condenser becomes clogged, for example, and ventilation is obstructed,
When the temperature of the condenser increases due to a failure of the motor 10, etc., the refrigerant cannot be sufficiently condensed and the cooling capacity of the evaporator decreases, but the abnormal temperature detector 13 detects that the temperature of the condenser has risen to, for example, +55°C. It closes at this point, lights up the abnormality indicator lamp L ₂ , and since the changeover switch 9B is closed to terminal a, the alarm buzzer sounds.
Since the BZ sounds, the user is notified of an abnormality at an early stage, and the stored products are prevented from deteriorating.

The above has described the operation in a state where both power supplies 1 and 15 are normally applied, but even if the switch 16 is closed, if the second power supply 15 is in a power outage state,
The fluorescent light 17 goes out, the anti-condensation heater 19 stops generating heat, and the blower drive motor 18 stops.
Cold air circulation within the storage room will no longer take place. At this time, when the defrost timer TM operates, the changeover switch 6 is closed to terminal b, the contact 8A is closed, and the evaporator is defrosted, generating heat that allows defrosting to be performed while the cold air is already being circulated. As the cold air is no longer circulated relative to the specified amount, excessive heat is generated, causing the temperature near the defrosting heater 11 to rise abnormally, and if electrical wiring is installed near the defrost heater 11, there is a risk of burning out the electrical wires. comes out. Also, the motor 18
is not operated, the electric compressor drive motor 3
Even if the store is in operation, cold air is not circulated and the storage room is no longer cooled, causing the product to deteriorate due to the temperature rise.

For this reason, in the embodiment, the relay coil 9 is de-energized when the second power supply 15 loses power. This opens contact 9A and de-energizes relay coils 4 and 8, resulting in contact 2A,
2B and 8A are opened to prohibit the operation of the motor 3 and the heat generation of the defrosting heater 11, thereby preventing wasteful operation and the occurrence of the above-mentioned burnout accident. Further, dew condensation does not occur because the dew prevention heater 19 does not generate heat. At the same time, the changeover switch 9B is closed to terminal b, and the alarm buzzer is activated regardless of the abnormal temperature detector 13.
The BZ is made to sound to notify the user of the power outage of the second power source 15. As a result, the user can quickly eliminate the abnormality in the second power supply 15 and return the show case to its normal cooling state. The alarm at this time can also be used as an alarm buzzer BZ for notifying an abnormality in the condenser, that is, the refrigeration cycle, so manufacturing costs can be reduced and the configuration can be simplified. Further, at this time, whether there is an abnormality in the refrigeration cycle or a power outage in the second power supply 15 can be easily determined by the lighting state of the abnormality indicator lamp _L2 .

Here, the abnormal temperature detector 13 is not limited to the condenser as in the embodiment, but may be configured to detect inside the storage room and close the contact at a predetermined abnormally high temperature. An alarm is issued for an abnormality in the blower drive motor 18 or electric compressor drive motor 3 that constitutes the cooling device.

(g) Effects of the invention According to the invention, in a low-temperature case that uses two types of power sources, the second
If the power supply stops, the changeover switch closes to the second terminal and the alarm is energized and issues an alarm regardless of the operation of the abnormality detector, so the user is notified of the power outage early. You can tighten it.
In this case, the alarm is activated by an alarm that is activated by an abnormality detector that detects abnormalities in the refrigeration cycle, which reduces manufacturing costs and simplifies the electrical wiring inside the case. It is highly effective.

[Brief explanation of drawings]

The figure shows an embodiment of the electric circuit of the low-temperature show case of the present invention. 1...First power supply, 3...Electric compressor drive motor, 9...Relay coil, 9B...Switchover switch, a...Terminal (first terminal), b...Terminal (second terminal) , 13... Abnormal temperature detector, 15...
2nd power supply, 19... Anti-dew heater, BZ... Alarm buzzer.

Claims (1)

[Scope of utility model registration request] an abnormality detector for the refrigeration cycle connected to a first power source to which a compressor drive motor of the refrigeration cycle is connected; an alarm driven by the abnormality detector; and a storage chamber opening connected to a second power source. A first terminal connected between a dew-proof heater and an electromagnetic relay coil for preventing dew condensation on the edge, the abnormal temperature detector and the alarm, and the first power source and the alarm. a second terminal, and a changeover switch for the electromagnetic relay that closes to the first terminal when the coil of the electromagnetic relay is energized and closes to the second terminal when the coil is de-energized. .