JPH04366381A - Cold temperature cabinet - Google Patents

Abstract

PURPOSE:To provide a low temperature storage which prevents the complete discharge of a battery. CONSTITUTION:A microcomputer 46 and a DC fan motor 14 are driven by a battery as their power source under the condition that an AC power source is cut off. The microcomputer 46 executes cold insulation operation which controls the operation of the DC fan motor for five hours after the AC power source is cut off. In the case when there is no connection of the AC power source for 72 hours after the end of this cold insulation operation, the supply to the microcomputer itself is also cut off.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-temperature refrigerator that uses a cold storage agent to keep a storage room at a low temperature.

0002

2. Description of the Related Art The applicant previously applied for a low-temperature warehouse for transportation in which a cold storage agent is frozen in advance using a cooling device, and then the interior of the storage chamber is cooled by the latent heat of melting of the cold storage agent.
The application was filed as No. 307926.

According to this application, a storage battery is charged by an AC power source, and a cooling device is operated by the AC power source to freeze the cold storage agent, and during transportation, the storage battery is used as a power source, and the temperature is determined based on the temperature of the storage room. A cold preservation operation is performed in which the blowing means is operated intermittently under the control of the control device, and cold air from the cold storage agent is sent to the storage chamber to maintain the storage chamber at a predetermined low temperature.

[0004] Such cold storage operation is carried out for a predetermined period such as 5 hours to ensure sufficient time for transportation, but after that, the cold storage operation is terminated and the ventilation means is not operated, resulting in a complete stoppage. .

[0005]

[Problems to be Solved by the Invention] In this way, in a low-temperature refrigerator, although the cooling of the storage compartment by the blower ends when the cold storage operation ends, the power supply for the control device itself is not able to store the storage compartment temperature setting value, etc. Therefore, power was still supplied from storage batteries. Therefore, if the low-temperature refrigerator is not used for a long time and the AC power supply is not connected, the storage battery will be completely discharged due to the long-term power supply to the control device, shortening the life of the storage battery itself, and There was an issue where charging took a long time when the power was reconnected.

The present invention has been made to solve the above problems, and an object thereof is to provide a low-temperature refrigerator that prevents the storage battery from completely discharging.

[0007]

[Means for Solving the Problems] The low-temperature refrigerator R of the present invention includes a storage chamber 2 for storing articles, a cold storage agent 6 for cooling the storage chamber 2, and a cold storage agent 6 driven by an AC power source (AC200V). a cooling device 7 that cools the cold storage agent 6; and a blowing means (DC fan motor) 14 that sends cold air from the cold storage agent 6 to the storage room 2;
It is equipped with a control device (microcomputer) 46 that controls the operation of the DC fan motor 14 based on the temperature of the storage room 2, and a storage battery 32.
The DC fan motor 14 is driven using the storage battery 32 as a power source, and the microcomputer 46 executes a cold storage operation that controls the operation of the DC fan motor 14 for 5 hours after the AC power supply is cut off, and then runs the AC power supply for 72 hours after the end of this cold storage operation. If there is no connection, the power supply to the microcomputer 46 itself is also cut off.

[0008]

[Operation] According to the present invention, if the low-temperature refrigerator R is not used for a long time, that is, 72 hours or more after the cold storage operation ends, and there is no connection to the AC power supply, the power supply from the storage battery 32 to the microcomputer 46 itself is cut off. Therefore, complete discharge of the storage battery 32 can be prevented.

[0009]

Embodiments Next, embodiments of the present invention will be explained based on the drawings. FIG. 1 is a block diagram of an electric circuit, and FIG. 2 is a longitudinal sectional view of the low-temperature refrigerator R.

The low-temperature refrigerator R includes a main body 1 made of a heat-insulating box, a storage chamber 2 formed in the main body 1 for storing articles,
A door 3 that opens and closes the storage room 2, a cold storage room 4 that communicates with the storage room 2 via a duct 5, a cold storage agent 6 stored in the cold storage room 4, and a cooling device 7 that cools the cold storage agent 6. It is configured. Here, the cold storage agent 6 has a freezing and melting temperature Ts of -
Use one at 25°C.

The cooling device 7 includes a compressor 8, an accumulator 9, a cooler 10 disposed in the cold storage chamber 4 so as to be in close thermal contact with the cold storage agent 6, and a capillary tube 11.
It is composed of a condenser 12 and a condenser blower 13. Further, the cold air cooled by the cool storage agent 6 is sent to the storage room 2 via the duct 5 by a DC fan motor 14 as a blowing means.

The air in the storage chamber 2 is supplied to the cold storage chamber 4 from the suction port 15.
The cold air from the cold storage chamber 4 is blown out from the outlet 16 of the duct 5 into the storage chamber 2. A cool storage agent temperature sensor 17 is attached to the cool storage agent 6 as a temperature detection means for detecting the temperature thereof. Further, the air outlet 16 is provided with an internal temperature sensor 1 that detects the temperature of the cold air blown into the storage room 2.
8 is provided. Furthermore, the temperature of the condenser 12 is detected by a condenser temperature sensor 19.

Casters 20 are attached to the bottom of the main body 1, and bumpers 21 are attached to the upper and lower ends of the outer peripheral surface of the main body 1. Further, a machine room 22 is formed in the rear corner of the lower part of the main body 1, and a compressor 8, a storage battery, etc., which will be described later, are housed therein. still,
In this embodiment, in order to obtain sufficient cooling capacity, two cooling devices 7 and two DC fan motors 14 each having the same size are installed.

In FIG. 1, a rectifier circuit 31 as a power supply circuit is connected to the a contact point of a switching relay 36, and the output of a storage battery 32 connected to a charging circuit 33 is connected to a relay coil Ry.
It is connected to the B contact of the switching relay 36 via the contact No. 6. The switching relay 36 functions as a switching means for switching the power source of a microcomputer (hereinafter referred to as microcomputer) 46 that constitutes the control device between an AC power source (200 VAC) and the storage battery 32 . That is, the common contact c of the switching relay 36 is connected to the microcomputer 46, and the contact is closed to a contact when AC power is connected, and is closed to contact b when AC power is disconnected. As a result, the microcomputer 46 uses the AC power source when the AC power source is connected, and the storage battery 3 when the AC power source is disconnected.
2 as a power source.

The storage battery 32 includes a resistor 3 as a current sensor.
4 are connected in series and output a voltage proportional to the charging current. Further, a voltage monitoring circuit 35 for monitoring the voltage of the storage battery 32 is connected to the common contact c of the switching relay 36.
The output is input to the microcomputer 46. The voltages generated by the cool storage agent temperature sensor 17, the internal temperature sensor 18, the condenser temperature sensor 19, and the resistor 34, which are composed of transistor sensors, are amplified by amplifier circuits 37, 38, 39, and 40, respectively, and are all sent to the microcomputer 46. is input. Furthermore, the output of the negative phase detection circuit 41 that detects the connection state of the three-phase AC power supply is also input to the microcomputer 46 .

Compressor motor 42 of two compressors 8
, 43 and the reverse phase detection circuit 41, the relay coils 44 and 45 switch contacts (not shown) to bring the AC power supply into a normal connection state, and are respectively relay coils Ry2.
, Ry3, Ry4, and Ry5 to the AC power source. The DC fan motors 14, 14 are connected to a common contact c of a switching relay 36 via a contact of a relay coil Ry1. These relay coils Ry1, Ry2
, Ry3, Ry4, Ry5, and Ry6 are connected to the output of the microcomputer 46, and the microcomputer 46 opens and closes each contact by controlling energization of these, and controls the operation and stopping of the compressor 8 and DC fan motor 14 as described later. do. Similarly, the microcomputer 46 also controls switching between normal phase and negative phase, and discharge control of the storage battery 32.

Here, like the microcomputer 46, when the DC fan motor 14 is connected to an AC power source, it operates using the AC power source via the rectifier circuit 31 and the switching relay 36, and when the AC power source is disconnected, it operates using the storage battery 32 as a power source. . That is, during the cold storage operation to freeze the cold storage agent 6, the DC fan motor 14 uses the output of the rectifier circuit 31 as a power source, and the storage battery 32 and charging circuit 33 are not used.

Further, a switch input line from an operation panel 47 provided with input means for inputting signals to the microcomputer 46 and various display means and a display output line to the operation panel 47 are connected to the microcomputer 46 . Furthermore, the output of the rectifier circuit 31 is connected to the microcomputer 4 via a power signal line 49.
6, and based on this, the microcomputer 46 determines whether or not there is an AC power source.

Next, the operation will be explained. When the low-temperature refrigerator R is connected to an AC power source (AC200V) and the microcomputer 46 is powered on for the first time, the contacts of the relay coil Ry6 are closed, and the switches SW1 to SW4, which are input means provided on the operation panel 47, are closed. The configuration operation status is read. The microcomputer 46 stores the read settings as long as the power is on. Here, the operation panel 47 is provided with a refrigerator switch SW1 for instructing the start of internal cooling, a temperature selection switch SW2 for selecting the internal temperature of the storage compartment 2 to +5°C which is the refrigerating temperature, and 0 which is the ice temperature. Temperature selection switch SW3 to select ℃, temperature selection switch SW4 to select -18℃ which is the freezing temperature, LED4 to LED6,
A display section 48 consisting of two 7-segment LEDs, S
When any one of SW2 to SW4 is operated, the microcomputer 46 lights up the LED4 to LED6 corresponding to the selected temperature. Further, the microcomputer 46 detects that the low-temperature refrigerator R is connected to the AC power source based on the output from the power signal line 49.

FIG. 3 shows temperature changes and operations of each part during operation, and FIGS. 4 and 5 show flowcharts of the control program of the microcomputer 46. At the delivery base, when the low-temperature warehouse R is connected to an alternating current power source (AC200V), charging of the storage battery 32 is started. Also, on the operation panel 47, S
It is assumed that W4 is operated and -18° C. is designated as the set temperature Tc. The microcomputer 46 has the switching relay 36 a.
Power is supplied from the rectifier circuit 31 through the contact, and starts at the same time as this power is supplied.In step 50, it is determined whether or not the cool storage agent temperature sensor 17 is short-circuited.If it is not short-circuited, the cool storage agent temperature is determined in step 51. It is determined whether the sensor 17 is disconnected this time. If there is no failure, it is determined in step 52 whether or not the compressor 8 is currently operating, and since it is stopped, in step 53 the temperature of the refrigerant 6 is -35°C.
It is determined whether or not the temperature is higher than that, and since the temperature is high at the start of operation, the compressor 8 is operated in step 54. As a result, the cool storage operation shown in FIG. 3 is started. Note that a short circuit or disconnection of the cool storage agent temperature sensor 17 can be determined by an abnormality in the output potential from the sensor.

If the compressor 8 is in operation in step 52, it is determined in step 55 whether the temperature of the refrigerant 6 is below -37°C, and if it is below, the compressor 8 is operated in step 56.
stop. As long as the cool storage agent temperature sensor 17 is normal and the AC power source (AC 200V) is connected, the compressor 8 is repeatedly operated and stopped under the above control.

In step 57, a subroutine for determining the completion of freezing of the cool storage agent 6 and the completion of charging of the storage battery 32 is executed. That is, there are two freezing determination conditions for the cold storage agent 6 here. One is that the temperature of the cold storage agent 6 based on the output of the cold storage agent temperature sensor 17 is -29 degrees Celsius lower than the freezing and melting temperature of -25 degrees Celsius. ℃ or below for more than 9 hours,
The other is -3, where the temperature of cold storage agent 6 is 7°C lower than -25°C.
This means that the temperature remained below 2°C for 10 minutes or more. If either one of these two conditions is satisfied, freezing of the cold storage agent 6 is considered to have been completed.

The charging state of the storage battery 32 is determined by inputting the voltage generated by the resistor 34 and calculating the charging current flowing through the storage battery 32 from that value. Consider it completed. When all of these steps are completed, the microcomputer 46 turns on the LED 2 to indicate that the cold storage operation is ready.

Next, in step 58, the refrigerator switch S
It is determined whether W1 has been pressed or not, and if it has not been pressed, it is determined in step 59 whether the freezing and charging have been completed, and since neither freezing nor charging has been completed since the power has just been turned on here, step 64 At this point, the DC fan motor 14 is stopped.

The conventional cold storage operation operation will be explained based on FIG. 3. The temperature of the cold storage agent 6 rapidly decreases due to the operation of the compressor 8, and the freezing temperature of the cold storage agent 6 reaches Ts about 3.5 hours after the start of operation. It reaches -25°C. However, due to the supercooling phenomenon of the cool storage agent 6, the cool storage agent 6 does not freeze immediately, and its temperature continues to fall further. Then, the temperature of the cold storage agent 6 is about -
Freezing begins when the temperature reaches 31°C, and the temperature of the cold storage agent 6 is approximately -
Return to 25°C. While the cold storage agent 6 is frozen, its temperature is -25
The temperature remains constant at ℃, but once the freezing ends, the temperature starts to drop again and becomes lower than -32℃.

In the process of the above-described operation, when the freezing and charging completion determination conditions of step 57 are satisfied, the process proceeds from step 59 to step 60, where it is determined whether the DC fan motor 14 is currently operating, and since it is not, step 61 is performed. The temperature of the storage compartment 2 based on the internal temperature sensor 18 is the set temperature Tc.
It is determined whether the temperature is +1°C or higher, and since the temperature of the storage chamber 2 is high here, the DC fan motor 14 is operated in step 63.
The cool storage operation is ended and the refrigerator internal cooling operation is started. This DC
By operating the fan motor 14, latent heat of fusion of the cool storage agent 6 or cold air cooled by the cooler 10 is circulated into the storage chamber 2, thereby cooling the storage chamber 2.

When the temperature of the storage chamber 2 based on the internal temperature sensor 18 reaches the set temperature Tc by this cooling, the process proceeds from steps 60 and 62 to step 64, and the DC fan motor 14 is stopped. In this way, DC fan motor 1
4 is repeatedly operated and stopped, and the temperature of storage room 2 is -18
Maintained around ℃.

Here, when the refrigerator switch SW1 is pressed during the cold storage operation, the cold storage agent 6 freezes or the storage battery 32 freezes.
Step 58
The process then proceeds to step 60, so that the cold storage operation is shifted to the internal cooling operation. This is performed when it is necessary to cool the food in the storage room 2 while freezing the cold storage agent 6.

[0029] Also, during the above-mentioned cold storage operation or refrigerator cooling operation, in step 50 or 51, the cold storage agent temperature sensor 17 is
If a failure is discovered, the process proceeds to step 65. In step 65, it is determined whether or not the DC fan motor 14 is in operation, and if it is not in operation, in step 66, the temperature of the storage compartment 2 based on the internal temperature sensor 18 is set to the set temperature Tc + 1°C.
(i.e. -17°C) or higher, and if the temperature is higher than that, the compressor 8 and the DC fan motor 14 are
is operated, and when the temperature of the storage compartment 2 based on the internal temperature sensor 18 reaches the set temperature Tc due to this cooling, step 6
Step 5 and step 67 proceed to step 69, where the compressor 8 and DC fan motor 14 are stopped.

That is, if a failure such as a short circuit or disconnection occurs in the cold storage agent temperature sensor 17, it will be impossible to determine whether the freezing of the cold storage agent 6 is complete, but even in that case, instead of stopping the entire system, the compressor 8 and the DC fan motor 14 are automatically controlled by comparing the temperature of the storage compartment 2 based on the internal temperature sensor 18 and the set temperature Tc, that is, the control of general refrigerator operation is performed. The DC fan motor 14 is repeatedly operated and stopped, and the temperature of the storage chamber 2 is maintained at around -18° C., which is the set temperature Tc. Therefore, although freezing control of the cold storage agent 6 is not performed, even if foods are stored in the storage chamber 2, at least the preservation of these foods is achieved.

Here, the microcomputer 46 displays the temperature inside the storage chamber 2 and the set temperature on the display section 48 during normal operation.
When a failure occurs in the cool storage agent temperature sensor 17, an error message such as E5 is displayed in the case of a disconnection, and E6 is displayed in the case of a short circuit. This notifies the user of the occurrence of a failure.

After or during the cold storage operation and refrigerator cooling operation as described above, articles such as food are stored in the low-temperature refrigerator R, disconnected from the AC power source, and loaded onto a delivery vehicle. When the AC power supply to the low-temperature refrigerator R disappears (AC power is turned off)
Next, a cold storage operation is started in which the storage chamber 2 is cooled by the latent heat of fusion of the cold storage agent 6. In FIG. 5, the control of the microcomputer 46 after the cold storage operation will be explained. The input from the power signal line 49 causes the microcomputer 46 to output an AC power source (AC200V).
) is detected, it is determined in step 82 whether the AC power supply is turned off, and in step 83 it is determined whether the stop flag is set.
count. Next, in step 85, it is determined whether the count of timer B has reached 5 hours, and if it has not, in step 86, cold preservation operation is executed.

In this cold storage operation, the microcomputer 46 and the DC fan motor 14 are supplied with power by discharging the storage battery 32 by switching the changeover switch 36 to the b contact. Further, the operation of the DC fan motor 14 is controlled by the microcomputer 46, and when the temperature of the storage compartment 2 measured by the internal temperature sensor 18 rises to the set temperature Tc + 1°C, the DC fan motor 14 starts operating.
When it descends to Tc, it will be stopped. As a result, the inside of the storage chamber 2 is maintained at around -18°C.

When five hours have elapsed since the AC power supply was turned off, the process proceeds from step 85 to step 87, where the cold storage operation is stopped and the operation of the DC fan motor 14 is stopped. These five hours are determined as enough time for the delivery vehicle to complete the delivery. Next, the process advances to step 88 to set a stop flag, and in step 89 the microcomputer 46 counts a 72-hour timer C as a function, and in step 90 it is determined whether the count of timer C has reached 72 hours. If so, return to the original state and proceed from steps 83 to 89.
Proceed to count.

If the low-temperature refrigerator R is left unattended without AC power connected for 72 hours after the cold storage operation is stopped, the count of timer C reaches 72 hours in step 90, and the stop flag and timer C are reset in step 91. At the same time, the contacts of the relay coil Ry6 are opened to stop discharging the storage battery 32, and as shown in FIG. 3, the power supply to the microcomputer 46 itself is also stopped. This prevents the storage battery 32 from being completely discharged, so
The life of the storage battery 32 can be extended, and the charging time can be shortened even when charging is started when the AC power source is turned on again.

[0036] Regarding each temperature and time listed in the above examples, the present invention is not limited to these values.
It goes without saying that various changes can be made depending on the capacity and capacity of the low-temperature refrigerator.

[0037]

[Effects of the Invention] According to the present invention, if the low-temperature refrigerator is not used for a certain period of time after the cold storage operation ends and the AC power supply is not connected, the power supply from the storage battery to the control device itself is cut off. , it is possible to prevent the storage battery from completely discharging. Therefore,
The life of the storage battery can be extended, and the charging time during recharging can be shortened.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an electric circuit.

FIG. 2 is a longitudinal cross-sectional view of the low-temperature refrigerator.

FIG. 3 is a characteristic diagram showing temperature changes and operations during operation.

FIG. 4 is a flowchart of a control program.

FIG. 5 is a flowchart of a control program.

[Explanation of symbols]

2 Storage room 6 Cold storage agent 7 Cooling device 14 DC fan motor 32 Storage battery 46 Microcomputer

Claims (1)

[Claims] 1. A storage chamber for storing articles, a cold storage agent for cooling the storage chamber, a cooling device driven by an AC power source to cool the cold storage agent, and a cooling device for supplying cold air from the cold storage agent to the storage chamber. The control device includes a blowing means for sending air, a control device for controlling operation of the blowing means based on the temperature of the storage room, and a storage battery, and when the AC power source is cut off, the control device and the blowing means operate the storage battery. Driven as a power source, the control device executes a cold storage operation for controlling the operation of the air blowing means for a predetermined period from the disconnection of the AC power source, and performs control when the AC power source is not connected for a certain period from the end of the cold storage operation. A low-temperature refrigerator characterized by cutting off the power supply to the device itself.