JPH1123074A - Freezer for freezer container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of freezing performance in the region of freezing operation suppressing the rise of discharging refrigerant temperature for a compressor (in other words, protecting the compressor). SOLUTION: A freezer for a freezer container is provided with a refrigerant circuit comprising a compressor 1, a condenser 2, an electronic expanding valve 4 and an evaporator 5 connected serially, a liquid injection circuit 9 injecting the outlet side liquid refrigerant of the condenser 2 on the intake side of the compressor 1, and an opening and closing valve 10 conducting or shutting off the liquid injection circuit 9. Arranging the controlling means of the opening of an electronic expansion valve 4 collecting the opening of the electronic expansion valve 4 to larger opening than the normal when the temperature To of the discharging gas refrigerant from the compressor 1 rises in the region of freezing operation and during the freezing operation required of high power freezing, the opening of the electronic expansion valve 4 is controlled to larger opening than the predetermined opening when the temperature To of discharging gas refrigerant from the compressor 1 rises, and both of protection of the compressor 1 and the prevention of the deterioration of freezing capability can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus for a refrigerating container, which prevents a decrease in refrigerating capacity in a refrigerating operation region.

[0002]

2. Description of the Related Art Generally, a refrigeration system for a refrigeration container includes a refrigerant circuit in which a compressor, a condenser, an electronic expansion valve, and an evaporator are sequentially connected. In order to prevent excessive rise (in other words, to protect the compressor), a method of injecting the liquid refrigerant at the outlet side of the condenser into the suction side of the compressor has been adopted.

[0003]

However, in the case of a conventional refrigeration apparatus for a refrigerated container, for example, even during a refrigeration operation in which the temperature in the refrigerator is higher than -10 ° C., or during a refrigeration operation in which the temperature in the refrigerator is lower than −10 ° C. Since the method of suppressing the rise in the refrigerant gas discharge temperature of the compressor by liquid injection is adopted, the amount of refrigerant supplied to the evaporator by the liquid injection is reduced in the refrigeration operation region requiring a large refrigeration capacity, and as a result, As a result, there was a problem that the refrigerating capacity was greatly reduced.

The present invention has been made in view of the above points, and suppresses a rise in the temperature of a refrigerant discharged from a compressor (in other words, while protecting the compressor), while maintaining the compressor in a refrigeration operation region. It is an object of the present invention to prevent a decrease in refrigeration capacity.

[0005]

In the basic configuration of the present invention (the invention of claim 1), as means for solving the above-mentioned problems, the compressor 1, the condenser 2, the electronic expansion valve 4, and the evaporator 5 are provided. A liquid injection circuit 9 for injecting the liquid refrigerant on the outlet side of the condenser 2 into the suction side of the compressor 1; and an on-off valve 10 for opening or closing the liquid injection circuit 9 In the refrigerating device for a refrigerating container provided with
In the refrigeration operation region, an electronic expansion valve opening control means for controlling the opening of the electronic expansion valve 4 to be larger than a predetermined opening when the discharge gas refrigerant temperature To of the compressor 1 rises is provided.

With the above configuration, when the discharge gas refrigerant temperature To of the compressor 1 rises during the refrigerating operation requiring a large refrigerating capacity, the electronic expansion valve 4
Is controlled to be larger than the predetermined opening. Therefore, the gas refrigerant at the outlet side of the evaporator 5 (in other words, the suction side of the compressor 1) becomes wet, and the gas refrigerant discharged from the compressor 1 is discharged using the electronic expansion valve 4 which is an essential part of the refrigeration system. The temperature To can be lowered. In addition, since the opening degree of the electronic expansion valve 4 is increased, the amount of circulating refrigerant increases, and the refrigeration capacity does not decrease as in the conventional liquid injection system.

In the refrigeration operation region, when the on-off valve control means for opening the on-off valve 10 when the discharge gas refrigerant temperature To of the compressor 1 rises is provided in the refrigeration operation region, during the refrigeration operation, When the discharge gas refrigerant temperature To of the compressor 1 rises, the liquid refrigerant is injected into the suction side of the compressor 1 via the liquid injection circuit 9, and the discharge gas refrigerant temperature To of the compressor 1 decreases. Can be done. In this case, since a refrigerating capacity that is not so large as compared with the refrigerating operation area is not required, there is no problem even if the amount of circulating refrigerant is slightly reduced.

[0008]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

As shown in FIG. 1, the refrigerating apparatus for a refrigerating container includes a refrigerant circuit in which a compressor 1, a condenser 2, a receiver 3, an electronic expansion valve 4, and an evaporator 5 are sequentially connected. 3 and the evaporator 5
A supercooling heat exchanger 6 for exchanging heat with a gas refrigerant guided from the apparatus to provide supercooling to the liquid refrigerant is provided. Reference numeral 7 denotes a condenser fan for cooling the condenser 2, and reference numeral 8 denotes an evaporator fan for supplying the inside air to the evaporator 3.

[0010] The refrigerant circuit is provided with a liquid injection circuit 9 for injecting a part of the liquid refrigerant guided from the receiver 3 into the suction side of the compressor 1. Reference numeral 10 denotes an electromagnetic on-off valve that operates as an on-off valve that is opened at the time of liquid injection.

The refrigeration apparatus for a refrigeration container includes:
Air temperature in the refrigerator (in other words, suction air temperature of evaporator 5)
A temperature sensor 11 serving as a temperature detecting means for detecting the temperature inside the refrigerator and a temperature sensor 12 serving as a detecting means for detecting the discharge gas temperature To of the compressor 1 are provided.

The temperature information detected by the temperature sensors 11 and 12 (that is, the in-compartment air temperature Tr and the discharge gas refrigerant temperature To) is input to a controller 13, and the controller 13 uses the temperature information based on the temperature information. Various arithmetic processes are performed, and the results are output to the electronic expansion valve 4 and the electromagnetic on-off valve 10 as control signals. That is, in the refrigeration operation range, the controller 13 controls the opening of the electronic expansion valve 4 to be larger than the predetermined opening when the discharge gas refrigerant temperature To of the compressor 1 rises. Function as a means,
In the refrigeration operation region, the compressor 1 has a function as opening / closing valve control means for opening the electromagnetic opening / closing valve 10 when the discharge gas refrigerant temperature To of the compressor 1 rises.

Next, the discharge temperature control in the refrigeration apparatus for a refrigeration container according to the present embodiment will be described in detail with reference to the flowchart shown in FIG.

[0014] is the compressor 1 is ON at Step S _1, the startup routine of the compressor 1 is confirmed that finished in step S _2, the temperature information from the temperature sensors 11 and 12 in step S ₃ (i.e., the internal air temperature Tr, the discharge gas refrigerant temperature to) is input, the internal air temperature Tr and the set value Trs (for example, the comparison between -10 ° C.) is made in step S _4. The set value Trs
Is the boundary between the refrigeration operation and the refrigeration operation.

[0015] The negative determination is made in step S ₄ (ie, T
In other words if (which is r> Trs and determination), if it is determined that the refrigerating operation region), the process proceeds to step S _5, the discharge gas refrigerant temperature To and the first set value of the compressor 1 Tos
₁ (eg, 120 ° C.). The first set value Tos ₁ is a discharge gas refrigerant temperature at which the compressor 1 enters an overheated state.

[0016] affirmative determination in step S ₅ (ie, T
o> Tos ₁ and determined) by if (in other words, when the compressor 1 is determined to be overheated), the process proceeds to step S _6, the solenoid valve 10 is opening operation, then step S
Return to ₁ . Then, the liquid refrigerant is injected into the suction side of the compressor 1 via the liquid injection circuit 9, so that the overheated state of the compressor 1 is eliminated, and the discharge gas refrigerant temperature To decreases.

[0017] The negative determination is made in step S ₅ (ie, T
o ≦ Tos ₁ and determination) if it is, the process proceeds to step S _7, the discharge gas refrigerant temperature of the compressor 1 To a second set value To
A comparison with s ₂ (eg, 116 ° C.) is made. The second
The set value Tos ₂ is a first set value To which is a discharge gas refrigerant temperature at which the compressor 1 enters an overheat state in order to prevent hunting.
there is a predetermined value by a temperature lower than s _1. Step S ₇
Affirmative (i.e., the To <Tos ₂ and determination) (in other words, if the overheating of the compressor 1 has been eliminated) if it is in, the process proceeds to step S _8, the solenoid valve 10 is closing operation , and then returns to the step S _1. In addition,
Negative determination in step S ₇ when it is (i.e., it determines that the To ≧ Tos _2), and then returns to step S ₁ is omitted subsequent control. That is, until an affirmative determination is made in step S ₇ is the solenoid valve 10 will become one being held open state.

Meanwhile, an affirmative decision (i.e., determined that Tr ≦ Trs) in step S ₄ (in other words, if it is determined that the freezing operation region) if it is, the process proceeds to step S _9, the compressor 1 Discharged gas refrigerant temperature To and first set value To
A comparison with s ₁ (eg, 120 ° C.) is made. An affirmative decision (i.e., a the To ≧ Tos ₁ determination) if has been (in other words, if the compressor 1 is determined to be overheated)
The samples the opening of the electronic expansion valve 4 at that time in step S _10, the opening degree of the electronic expansion valve 4 is set to the sampling value + 100 pulses in step S ₁₁ (i.e., the electronic expansion valve 4 opening Is made larger than the predetermined opening degree).

[0019] Then, the discharge gas refrigerant temperature To and the first set value Tos ₁ of the compressor 1 at step S ₁₂ (for example,
120 ° C.), where a positive determination is made (ie,
In other words if (where the To ≧ Tos ₁ and determination) have been, when the compressor 1 is determined to be overheated), the step S ₁₃
Opening of the electronic expansion valve 4 is increased by 1 pulse / 10 seconds, and then returns to step S ₁ in. Then
Since the refrigerant at the outlet side of the evaporator 5 (that is, the suction side of the compressor 1) is in a wet state, the overheated state of the compressor 1 is eliminated, and the discharge gas refrigerant temperature To decreases.

[0020] The negative determination is made in step S ₁₂ (ie, T
o <when Tos ₁ judged) ed, the process proceeds to step S _14, the discharge gas refrigerant temperature To and the first set value T of the compressor 1
os ₁ (for example, 120 ° C.), and a positive determination is made here (that is, To ≦ Tos ₁ is determined) (in other words, when the overheated state of the compressor 1 is eliminated).
The degree of opening of the electronic expansion valve 4 is returned to the sampling values described above in step S _15, and then returns to step S _1.

As described above, in the present embodiment, when the discharge gas refrigerant temperature To of the compressor 1 rises during the refrigerating operation requiring a large refrigerating capacity, the opening of the electronic expansion valve 4 is increased. Since the opening is controlled to be larger than the opening at that time, the gas refrigerant at the outlet side of the evaporator 5 (in other words, the suction side of the compressor 1) is in a wet state, which is indispensable as a refrigeration system. Using the electronic expansion valve 4 as a component, the discharge gas refrigerant temperature To of the compressor 1 can be reduced. In addition, since the opening degree of the electronic expansion valve 4 is increased, the amount of circulating refrigerant increases, and the refrigeration capacity does not decrease as in the conventional liquid injection system.

On the other hand, when the discharge gas refrigerant temperature To of the compressor 1 rises during the refrigeration operation, the liquid refrigerant is injected into the suction side of the compressor 1 via the liquid injection circuit 9 as in the conventional case. In addition, the temperature of the gas refrigerant discharged from the compressor 1 can be reduced.

By the way, outside temperature 38 ° C / SP-30 ° C
Under the above conditions, the liquid injection specification in the refrigeration operation region and the operation time rate without load in the refrigerator and the minimum temperature reached in the refrigerator when the load in the refrigerator was turned on were compared for both of the electronic expansion valve opening control specification and the following. The results in Table 1 were obtained.

[0024]

[Table 1]

According to the above results, in the refrigeration operation region, the electronic expansion valve opening control is superior to the liquid injection operation (that is, the operation time ratio is 7).
6.6% → 94.2%, lowest temperature in the refrigerator -28.5 ° C
→→ 27.1 ° C.).

[0026]

According to the invention of the present application (the invention of claim 1),
Liquid injection for providing a refrigerant circuit in which a compressor 1, a condenser 2, an electronic expansion valve 4, and an evaporator 5 are sequentially connected, and injecting a liquid refrigerant at an outlet side of the condenser 2 to a suction side of the compressor 1. Circuit 9 and an on-off valve 10 for opening or closing the liquid injection circuit 9
In the refrigerating apparatus for a refrigerating container, the discharge gas refrigerant temperature To of the compressor 1 is in the refrigerating operation region.
The electronic expansion valve opening control means for controlling the opening of the electronic expansion valve 4 to be larger than a predetermined opening when the pressure of the compressor 1 rises is increased. When the gas refrigerant temperature To rises, the opening degree of the electronic expansion valve 4 is controlled to be larger than the predetermined opening degree, so that the outlet side of the evaporator 5 (in other words,
The gas refrigerant at the suction side of the compressor 1) becomes wet, and the temperature To of the gas refrigerant discharged from the compressor 1 can be reduced by using the electronic expansion valve 4, which is an essential component of the refrigeration system, and the electronic expansion valve By increasing the opening degree of 4, the amount of circulating refrigerant can be increased, and there is an excellent effect that the refrigerating capacity does not decrease as in the conventional liquid injection system.

As described in the second aspect of the present invention, when the on-off valve control means for opening the on-off valve 10 when the discharge gas refrigerant temperature To of the compressor 1 rises is provided in the refrigeration operation region, during the refrigeration operation, When the discharge gas refrigerant temperature To of the compressor 1 rises, the liquid refrigerant is injected into the suction side of the compressor 1 via the liquid injection circuit 9, and the discharge gas refrigerant temperature To of the compressor 1 decreases. Can be done.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram of a refrigeration container refrigeration apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating discharge temperature control in the refrigeration apparatus for a refrigeration container according to the embodiment of the present invention.

[Explanation of symbols]

1 is a compressor, 2 is a condenser, 4 is an electronic expansion valve, 5 is an evaporator, 9 is a liquid injection circuit, 10 is an on-off valve (electromagnetic on-off valve), 11 is an internal temperature detecting means (temperature sensor), 12 Denotes discharge temperature detecting means (temperature sensor), 13
Is the controller, and To is the discharge gas refrigerant temperature.

Claims (2)

[Claims] 1. A refrigerant circuit comprising a compressor (1), a condenser (2), an electronic expansion valve (4), and an evaporator (5) connected in order, and an outlet side of the condenser (2). A liquid injection circuit (9) for injecting the liquid refrigerant into the suction side of the compressor (1), and an on-off valve (10) for opening or closing the liquid injection circuit (9)
Wherein the opening degree of the electronic expansion valve (4) is higher than a predetermined opening degree when the discharge gas refrigerant temperature (To) of the compressor (1) rises in a refrigeration operation region. A refrigeration apparatus for a refrigeration container, further comprising electronic expansion valve opening control means for controlling the size of the refrigeration container to increase. 2. An on-off valve control means for opening the on-off valve (10) when the discharge gas refrigerant temperature (To) of the compressor (1) rises in a refrigeration operation region. The refrigeration apparatus for a refrigeration container according to claim 1.