JPH02122182A - Low temperature holding apparatus - Google Patents

Abstract

PURPOSE:To keep a heat insulated compartment at a specified temperature by providing a controller consisting of a temperature lowering device that puts a cooling device into operation when the temperature in the heat insulated compartment detected by a temperature detector is higher than a set temperature, and a temperature raising controller that puts a fan into operation when it is lower than a set temperature. CONSTITUTION:A microcomputer 51 of a controller 50 controls power supply to first and second relay coils 56 and 57 according to the states of a refrigerating operation switch 52, a temperature keeping switch 53, a temperature setting device 54, and a temperature detector 55. When the temperature of a heat insulated compartment 10 is higher than a set temperature, the controller 50 controls so as to supply electric power to a magnetic clutch 47 to put a refrigerating cycle 40 into operation. Then, the air in a chiller unit 20 is cooled by a refrigerant evaporator 41, and blown into the heat insulated compartment 10 by a fan 30 so as to reduce the temperature in the heat insulated compartment 10. When the temperature in the heat insulated compartment is lower than the set temperature, the controller 50 controls so as to electrify the fan 30 for the compartment, and the generated heat is carried by air current to the heat insulated compartment 10 through the chiller unit 20 to raise the temperature of the heat insulated compartment 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a low temperature maintenance device that maintains the temperature inside a heat insulating chamber (hereinafter referred to as the heat insulating chamber) mounted on a vehicle at a set temperature.

[Prior Art] A low temperature maintenance device includes a cooling device that cools air in an insulated chamber that is insulated from the outside, a blower that generates an air flow in the insulated chamber, and a control device that controls the cooling device and the blower. Note that the blower increases the amount of air cooled by the cooling means by generating an air flow within the insulation chamber, and also stirs the air within the insulation chamber to equalize the temperature within the insulation chamber.

The conventional control device controls the cooling capacity of the cooling means according to the output of the temperature detection means that detects the temperature inside the insulation room, and maintains the temperature inside the insulation room at the temperature set by the temperature setting means. .

In addition, the cooling capacity of the cooling means of the blower is reduced,
Alternatively, when the blower is stopped, its operation is reduced or stopped, preventing the heat generated by the blower from increasing the temperature inside the insulated room, reducing power consumption, and extending the life of the blower.

[Problems to be Solved by the Invention] However, conventional low temperature maintenance devices have only been able to reduce the temperature within the heat insulating chamber. Therefore, when the temperature outside the insulation chamber (hereinafter referred to as outside the insulation chamber) falls below the set temperature, the temperature inside the insulation chamber falls below the set temperature.

The present invention has been made in view of the above circumstances, and its purpose is to maintain the temperature inside the insulation room at the set temperature even if the temperature outside the insulation room falls below the set temperature set by the temperature setting means. The aim is to provide a low temperature maintenance device that can

[Means for Solving the Problems] In order to achieve the above object, the low temperature maintenance device of the present invention has a heat insulating chamber 1 insulated from the outside, as shown in FIG.
a cooling means 2 for cooling the air in the heat insulating chamber 1; a blower 3 provided in the heat insulating chamber 1 to generate an air flow in the heat insulating chamber 1; and a temperature detecting device for detecting the temperature in the heat insulating chamber 1. Detection means 4, the heat insulation chamber 1 detected by the temperature detection means 4;
a temperature lowering means 5 that operates at least the cooling means 2 to lower the temperature inside the heat insulating chamber 1 when the temperature inside the heat insulating chamber 1 is higher than a set temperature; Adopt technical means comprising: a control device 7 equipped with a temperature raising means 6 for operating the blower 3 and raising the temperature inside the insulation chamber 1 when the temperature inside the insulation chamber 1 is lower than the set temperature; do.

[Operation] The operation of the low temperature maintenance device configured as described above will be explained.

When the temperature outside the insulation room is higher than the set temperature inside the insulation room.

The temperature lowering means of the control device operates at least the cooling means when the temperature inside the heat insulation chamber detected by the temperature detection means is higher than the set temperature. Then, the cooling means cools the air inside the heat insulating chamber.

At this time, when the blower is activated, the blower generates an air flow inside the insulation chamber, increasing the amount of air cooled by the cooling means, increasing the cooling capacity inside the insulation chamber, and increasing the amount of air cooled by the cooling means. The air is diffused by the blower, and the temperature within the insulated room becomes uniform.

Conversely, if the temperature outside the insulation room is lower than the set temperature inside the insulation room.

The temperature raising means of the control device operates the blower when the temperature inside the heat insulating chamber detected by the temperature detection means is lower than the set temperature. Then, the air inside the heat insulating chamber is heated by the heat generated by the operation of the blower.

Then, the air heated by the blower is diffused by the blower, and the temperature inside the heat-insulating room is made uniform.

[Effects of the Invention] Since the present invention is configured as described above,
This produces the effects described below.

When the temperature inside the insulation room is higher than the set temperature, the temperature inside the insulation room is kept at the set temperature by the temperature lowering means, and when the temperature inside the insulation room is lower than the set temperature, the temperature inside the insulation room is set by the temperature raising means. maintained at temperature.

[Example] Next, an example in which the low temperature maintenance device of the present invention is applied to a refrigerated vehicle will be described with reference to the drawings.

Figure 2 shows a schematic diagram of a refrigerated truck.

This refrigerating vehicle is equipped with a heat insulating chamber 10 insulated from the outside by a heat insulating material or the like in the rear half of the vehicle.

A cooling unit 20 is attached above the front part of this heat insulation chamber 10. This cooling unit 20 has an inlet 21 on the lower surface and an outlet 22 on the rear.

In addition, inside the cooling unit 20, air inside the heat insulating chamber 10 is sucked through an inlet 21, and the sucked air is sent to an outlet 22.
A blower 30 for inside the refrigerator is attached to blow air from the inside of the heat insulating chamber 10. The blower 30 for inside the refrigerator is a blower according to the present invention that generates an air flow inside the heat insulating chamber 10 when operated, and is energized and controlled by the control device 50 below.

A refrigeration cycle 40 is installed in the ventilation passage in the cooling unit l-20.
A refrigerant evaporator 41 is installed. The refrigeration cycle 40 has a well-known configuration including, in addition to the refrigerant evaporator 41, a refrigerant compressor 42, a refrigerant condenser 43, a receiver 44, a refrigerant pressure reducing device 45, and a refrigerant pipe 46 connecting these. The refrigerant evaporator 41 is a cooling means of the present invention, in which the refrigerant flowing therein absorbs heat from the air flowing in the cooling unit 20 and evaporates, so that the refrigerant evaporator 41
The air passing through is cooled and the inside of the heat insulation chamber 10 is cooled. The refrigerant compressor 42 includes an electromagnetic clutch 47, and when the electromagnetic clutch 47 is energized, it transmits the rotational torque of an engine (not shown) to the refrigerant compressor 42. Further, the refrigerant condenser 43 includes a condenser blower 48 for forcibly exchanging heat between the refrigerant passing through the inside and air. Note that the electromagnetic clutch 47 and the condenser blower 48 are energized and controlled by a control device 50 below.

The above-mentioned internal air blower [30, electromagnetic clutch 47, and condenser air blower 48] are energized and controlled by a control device 50. FIG. 3 shows an example of the electric control circuit of the control device W50. The control device 50 of this embodiment includes a microcomputer 51. The microcomputer 51 controls the energization of the first relay coil 56 and the second relay coil 57 according to the states of the refrigeration operation switch 52, the heat retention switch 53, the temperature setting means 54, and the temperature detection means 55.

The refrigeration operation switch 52 is manually operated by a user such as a vehicle occupant, and is turned on by the user when the user wants to lower the temperature inside the insulation chamber 10 to the temperature set by the temperature setting means 54. It is something.

The heat retention switch 53 is used when the temperature outside the heat insulation chamber 10 falls below the set temperature set by the temperature setting means 54 and when the temperature inside the heat insulation room 10 is not desired to fall below the set temperature. It is turned on by the user. The temperature setting means 54 is a variable resistor, and is used to manually set the temperature inside the heat insulation chamber 10 as desired by the user.

The temperature detection means 55 is a thermistor that detects the temperature inside the heat insulation chamber 10. When the first relay coil 56 is energized, the relay switch 56a is turned on and off.
This is to energize the electromagnetic clutch 47 and the condenser blower 48.

When the second relay coil 57 is energized, the relay switch 57a turns ON and energizes the internal air blower 30.

Note that the reference numeral 58 shown in the figure represents a battery as a power source for the vehicle, and the reference numeral 59 represents a key switch.

Next, the operation of the microcomputer 51 will be explained based on the flowchart in FIG.

(starting when the refrigeration operation switch 52 is turned on with the key switch 59 turned on), and in step S1 it is determined whether the heat retention switch 53 is turned on or not.

If the determination result in step S1 is NO, in step S2
It is determined whether the temperature within 0 is higher than the set temperature set by the temperature setting means 54. This step S
If the determination result in step 2 is YES, in step S3,
The first relay coil 56 and the second relay coil 57 are energized, and then the process returns. If the judgment result in step S2 is NO, step S4
At this point, the first relay coil 56 and the second relay coil 57 are de-energized, and then the process returns.

If the judgment result in step S1 is YES, step S
5, the heat insulating chamber 10 detected by the temperature detection means 55
It is determined whether the temperature inside is higher than the set temperature set by the temperature setting means 54. If the determination result in step S5 is YES, in step S6, the first relay coil 56 and the second relay coil 57 are energized, and then the process returns. If the determination result in step S5 is NO, then in step S7, the first relay coil 56 is de-energized and the second relay coil 57 is energized. and then return.

Note that the operations from step S2 to step S4 indicate the operation of the temperature lowering means of the present invention programmed in the microcomputer 51, and the operations from step S5 to step S7
shows the operation of the temperature increasing means of the present invention programmed into the microcomputer 51.

Next, the operation of the above embodiment will be briefly explained.

b) When the temperature outside the heat insulation chamber 10 is higher than the temperature set by the temperature setting means 54. In this case, it is assumed that the user has turned on the refrigeration operation switch 52 but has not turned on the heat retention switch 53.

Immediately after startup, when the temperature inside the heat insulating chamber 10 is higher than the set temperature, the electromagnetic clutch 47, the condenser blower 48, and the refrigerator blower 30 are energized by the action of the control device 50.

The refrigeration cycle 40 is activated by energization of the electromagnetic clutch 47, and the refrigerant evaporator 41 cools the air within the cooling units 1 to 20. Then, the cooled air is sent to the air blower 3 for inside the refrigerator.
0 is blown out from the cooling unit 20 into the heat insulating chamber 10, thereby lowering the temperature inside the heat insulating chamber 10.

Then, when the temperature inside the insulation chamber 10 falls to the set temperature,
The control device 50 de-energizes the electromagnetic clutch 47, the condenser blower 48, and the refrigerator blower 30.

Then, since the refrigerant evaporator 41 does not cool the air in the heat insulating chamber 10, heat from outside the heat insulating chamber 10 is transmitted into the heat insulating chamber 10 little by little via the heat insulating material that constitutes the heat insulating chamber 10.

When the temperature inside the heat insulating chamber 10 becomes higher than the set temperature, the electromagnetic clutch 47, the condenser blower 48, and the refrigerator blower 30 are energized by the action of the control device 50.

Note that although the internal air blower 30 generates heat when operating, the cooling capacity of the refrigerant evaporator 41 is much larger than the amount of heat generated by the air blower 30. For this reason, the blower 30
Even if heat is generated, the inside of the heat insulating chamber 10 is cooled by the operation of the refrigerant evaporator 41.

Ex) When the temperature outside the heat insulation chamber 10 is lower than the temperature set by the temperature setting means 54. In this case, the user turns on the heat retention switch 53 together with the refrigeration operation switch 52.

Immediately after startup, if the temperature inside the insulation chamber 10 is lower than the set temperature, the control device 50 will start blowing air 1) 130 for the inside of the refrigerator.
energized only.

Then, the air blower 30 for the inside of the refrigerator is activated, and thereby the air blower 30 generates heat. The heat generated by the blower 30 is blown out from the cooling unit 20 into the heat insulating chamber 10 by the air flow generated by the blower 30, raising the temperature in the heat insulating chamber 10 by 1.

Then, when the temperature inside the insulation chamber 10 rises to the set temperature,
By the action of the control device jf50, in addition to the internal air blower 30, the electromagnetic clutch 47 and the condenser air blower 48 are energized. Then, as described above, the refrigerant evaporator 4
1 cools the air inside the heat insulating chamber 10.

When the temperature inside the heat insulation chamber 10 becomes lower than the set temperature, the control device ff50 de-energizes the electromagnetic clutch 47 and the condenser fan 48, and only the refrigerator fan 30 is energized again. .

By repeating item 1 above, the temperature inside the heat insulating chamber 10 is maintained close to the set temperature even if the temperature outside the heat insulating chamber 10 is lower than the set temperature.

In addition, this example adds a heat retention switch to a current refrigerated vehicle (equipped with a refrigerant evaporator and a blower in an insulated chamber, and whose temperature is controlled by a control device using a microcomputer) and the programming of the microcomputer. Since it can be implemented by making changes, it also has the advantage of being able to be provided at low cost.

(Modification) In this example, in order to explain the basic operation,
Although an example without hysteresis is shown, when actually installed in a vehicle, it will have hysteresis as shown in Figure 5 (operation by temperature lowering means) and Figure 6 (operation by temperature raising means). to program a microcomputer.

In this embodiment, an example is shown in which the temperature raising means and the temperature lowering means are switched by the heat retention switch, but the refrigeration operation switch and the heat retention switch may be combined into one switch. Furthermore, instead of the heat retention switch, an outside temperature detection means for detecting the temperature outside the insulation room may be provided, and the temperature raising means and the temperature lowering means may be switched depending on the difference between the temperature outside the insulation room and the set temperature. Note that by doing this, it can be automated. Further, the temperature increasing means and the temperature lowering means may be switched depending on the difference between the temperature in the heat insulating chamber and the set temperature. Note that by doing this, it is possible to automate the process and also to eliminate the need for a heat retention switch and outside temperature detection means.

Although we have shown an example in which the temperature reduction means, temperature and valve means are programmed into a microcomputer, it is also possible to configure the temperature reduction means and temperature and valve means by a discrete circuit using a comparator, etc., without using a microcomputer. It's okay.

Regarding the operation of the temperature raising means, we have shown an example in which the blower is always operated, and when the temperature inside the insulation room rises by 10°C, the cooling means is activated to adjust the temperature inside the insulation room. However, the air flow rate (current flow amount) of the blower and the 0N-O
By controlling the FF operation, the amount of heat generated by the blower may be controlled and the temperature within the heat insulating chamber may be adjusted.

Although we have shown an example of using a refrigerant evaporator as a cooling means, there are also air compression type refrigeration cycles that radiate and absorb heat by compressing air and expanding fat, and semiconductor type refrigeration cycles that radiate and absorb heat by energizing semiconductors. Other cooling means such as an element may also be used.

Although an example in which the present invention is applied to a refrigerated vehicle has been shown, the present invention can also be applied to other low temperature maintenance devices, such as small vehicle refrigerators installed in ordinary passenger cars, and stationary refrigerators used in general households and businesses. May be applied.

[Brief explanation of drawings]

Fig. 1 is a schematic block diagram showing the configuration of the present invention, Fig. 2 is a schematic diagram of a refrigerating vehicle, Fig. 3 is an electric circuit diagram of a control device, and Fig. 4 is a schematic block diagram showing the configuration of the present invention.
The figure is a flowchart showing the operation of the microcomputer, and FIGS. 5 and 6 are time charts showing an example of the operation in which hysteresis is provided for temperature control in the heat insulating chamber. In the diagram: 1...Insulation chamber 2...Cooling means 3...
-Blower 4...Temperature detecting means 5...Temperature lowering means 6...Temperature increasing means 7...Control device

Claims (1)

[Scope of Claims] 1) (a) A heat insulating chamber insulated from the outside; (b) cooling means for cooling the air in the heat insulating chamber; (c) a cooling means provided in the heat insulating chamber, which cools air within the heat insulating chamber; (d) (d-1) Temperature detection means for detecting the temperature inside the insulation chamber; (d-2) The temperature inside the insulation chamber detected by the temperature detection means is lower than a set temperature. (d-3) when the temperature inside the insulation chamber detected by the temperature detection means is lower than the set temperature; A low temperature maintenance device comprising: a control device including a temperature raising means for operating the blower and raising the temperature inside the heat insulating chamber.