JPH0730980B2 - Refrigeration system operation controller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to operation control of a refrigerating apparatus, particularly a container refrigerating apparatus, and more particularly to measures for controlling an opening of an expansion valve when a refrigerant temperature sensor is abnormal. Is.

(Prior Art) Conventionally, as an operation control device for this type of refrigeration system,
In order to keep the internal temperature at a set value, for example, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent Publication No. 205057, a refrigerant circulation circuit is formed by sequentially maintaining a compressor with an adjustable capacity, a condenser, an expansion valve with an adjustable opening, and an evaporator, and evaporating the evaporator. A temperature sensor and an outlet-side refrigerant temperature sensor are provided, and the opening degree of the expansion valve is controlled by the detection signals of both sensors so that the degree of superheat becomes a predetermined value.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional one, no backup means is provided for the case where the refrigerant temperature sensor has an abnormality such as a disconnection or a short circuit. Therefore, when there is an abnormality in the sensor, the refrigeration system itself is operating under various operating conditions and fluctuations in the internal heat load capacity,
There is a problem that the expansion valve opening cannot be controlled appropriately, and thus it is difficult to operate the refrigeration apparatus itself accurately.

Especially, in the refrigeration equipment provided in the refrigeration container,
It is important because it directly leads to freezing, dehydration, and spoilage of the goods in the warehouse, and an appropriate backup means has been desired.

The present invention has been made in view of such a point, the abnormality of the refrigerant temperature detection means of the evaporator inlet and outlet, especially, the air temperature of the suction side or the outlet side of the evaporator or the refrigerant temperature of the normal refrigerant temperature detection means By controlling the opening degree of the expansion valve based on the above, it is an object to solve the above problems.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the means taken by the invention according to claim (1) is, as shown in FIG. 1, first, a compressor (1) and a condenser ( 3), expansion valve with adjustable opening (5)
And a refrigerating apparatus provided with a refrigerating and circulating circuit (8) in which an evaporator (6) is connected in series in a closed circuit. An inlet side refrigerant temperature detecting means (Th1) for detecting the inlet side refrigerant temperature of the evaporator (6) and an outlet side refrigerant temperature detecting means (Th for detecting the outlet side refrigerant temperature of the evaporator (6) (Th).
2) and the outputs from both the refrigerant temperature detecting means (Th1) and (Th2), and the opening degree of the expansion valve (5) so that the temperature difference between the outlet side refrigerant temperature and the inlet side refrigerant temperature becomes constant. Expansion valve control means (12) for controlling the above, and the refrigerant temperature detection means (Th
(1), (Th2) at least one of the abnormality detection means (16) for detecting an abnormality and a setting means (2) for setting a desired internal temperature
2), a blown air temperature detecting means (Th4) for detecting the blown air temperature of the evaporator (6), and a rapid setting in which the set temperature in the refrigerator is set within a predetermined value or more by the setting means (22). During the refrigerating operation, when the abnormality detecting means (16) outputs an abnormality signal, the expansion valve control means (12) controls the opening degree of the expansion valve (5) and the blowing temperature of the evaporator (6). A control change means (171) for changing the control based on the temperature difference from the temperature is provided.

The means taken by the invention according to claim (2) is the outlet temperature detecting means (Th3) and the control changing means (1) according to claim (1).
71), instead of the blown air temperature detecting means (Th4) for detecting the blown air temperature of the evaporator (6), and the setting means (2
The abnormality detecting means (16) during the quick freezing operation in which the set temperature in the refrigerator is set within the range less than the predetermined value by 2).
Outputs an abnormal signal, the opening valve control of the expansion valve (5) by the expansion valve control means (12) is changed to control based on the temperature difference between the set temperature in the cold storage and the intake air temperature of the evaporator (6). The control change means (172) is provided.

The means taken by the invention according to claim (3) is the blowout temperature detecting means (Th3) and the control changing means (1) according to claim (1).
71), instead of the calculating means (271) for calculating the outlet side refrigerant temperature of the evaporator (6) based on the set temperature inside the refrigerator set by the setting means (22), When the abnormality detection means (16) outputs an abnormality signal during the refrigeration operation within a predetermined temperature range having a predetermined width, the expansion valve control means (112) controls the expansion valve (5) to the outlet. The configuration is provided with a control changing means (173) for changing the control to the control based on the refrigerant temperature of the side refrigerant temperature detecting means (Th2) and the calculated temperature of the calculating means (271).

Further, in the means taken by the invention according to claim (4), instead of the control changing means (173) according to claim (3), the inside temperature is within a predetermined temperature range having a predetermined width with respect to the set temperature. During the refrigerating operation, when the abnormality detection means (16) outputs an abnormality signal, the expansion valve control means (12) controls the expansion valve (5) to control the refrigerant of the inlet side refrigerant temperature detection means (Th1). The control means (174) for changing the control based on the temperature and the temperature calculated by the calculation means (271) is provided.

Further, the means taken by the invention according to claim (5) is configured such that the control changing means (171) and (174) according to claims (1) to (4) are provided.

(Operation) With the above configuration, in the invention according to claim (1), when the refrigerant temperature detecting means (Th1) and (Th2) are normal, the expansion valve (5) causes the difference in refrigerant temperature between the inlet and outlet of the evaporator (6). The opening degree is controlled so that the temperature difference becomes constant based on the above. Then, during the quick freezing operation in the refrigerator and when the preset temperature in the refrigerator is a predetermined temperature, for example, -5 ° C or higher and 25 ° C or lower, the outlet side and inlet side refrigerant temperature detecting means (Th2) of the evaporator (6). ，
When an abnormality occurs in at least one of (TH1), an abnormality signal from the abnormality detection means (16) causes the control change means (171) to change the control of the expansion valve control means (12) to cause expansion. The opening control of the valve (5) is controlled based on the set temperature in the refrigerator and the temperature of the air blown from the evaporator (6).

Further, in the invention according to claim (2), when the internal quick-freezing operation is performed and the internal preset temperature is lower than -5 ° C, for example,
Evaporator (6) outlet side and inlet side refrigerant temperature detecting means (Th
2) If there is an abnormality in at least one of (TH1),
In response to a signal from the abnormality detecting means (16), the control changing means (172) changes the control of the expansion valve control means (12) to control the opening degree of the expansion valve (5) and the evaporator set temperature and the evaporator (5). Control is performed based on the suction air temperature of 6).

Further, in the invention according to claim (3), when an abnormality occurs in the refrigerant temperature detection means (TH1) on the inlet side of the evaporator (6) when the internal cold storage temperature is within the set temperature range, The control change means (173) receives a signal from the detection means (16),
By changing the control of the expansion valve control means (12), the opening degree control of the expansion valve (5) is controlled by the inlet side refrigerant temperature based on the internal cold storage temperature.

Further, in the invention according to claim (4), when an abnormality occurs in the refrigerant temperature detecting means (TH2) on the outlet side of the evaporator (6) when the set temperature in the refrigerator is within the set temperature range, Control change means (174) by a signal from the abnormality detection means (16)
Changes the control of the expansion valve control means (12) and controls the opening degree control of the expansion valve (5) by the outlet side refrigerant temperature based on the internal cold storage temperature.

In the invention according to claim (5), the above claim (1)
From (4) to (4), the control changing means (171) to (17)
4) is performed.

With the above operation, in the present invention, even when the refrigerant temperature detecting means (Th1), (Th2) at the evaporator inlet / outlet is abnormal, when the internal cold storage is within the preset temperature range during the internal quick freezing operation. Regardless, the opening degree of the expansion valve is appropriately controlled.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 2, (A) is a refrigerating device provided in a refrigerating container or the like, (1) is a compressor with an unloader capable of changing the capacity to 33%, 67% and 100% in three stages, 3) is a condenser equipped with an air cooling fan (F1) and a motor (MF1),
(4) is a receiver, (5) is a PID-controlled electronic expansion valve, (6) is an evaporator with an internal fan (F2) and a motor (MF2), and (7) is an accumulator. Equipment (1), (3), (4), (5), (6), (7)
Are connected in series by refrigerant pipes in the above-mentioned order to form a refrigerant circulation circuit (8). By circulating the refrigerant through the refrigeration circulation circuit (8) by the compressor (1), the condenser ( In 3), the heat of the refrigerant gas is released to the outside of the refrigerator to liquefy the refrigerant gas, and the evaporator (6) vaporizes the refrigerant gas to absorb the heat in the refrigerator and thereby freeze the inside of the refrigerator. Is configured.

Further, (2) is a three-way proportional valve provided between the compressor (1) and the condenser (3), and (9) has one end connected to the three-way proportional valve (2) and the other. A hot gas bypass line whose end bypasses the condenser (3), the receiver (4) and the electronic expansion valve (5) and is connected to the suction side refrigerant pipe (10) of the evaporator (6). The gas bypass line (9) includes a drain pan heater section (11). Also, (HPS) is a pressure sensor for high pressure, (Th1) and (Th2)
Is a refrigerant temperature sensor which is a refrigerant temperature detecting means for detecting an inlet refrigerant temperature and an outlet refrigerant temperature of the evaporator (6),
(Th3) and (Th4) are air temperature sensors that are in-compartment temperature detecting means for detecting the intake air temperature and the blown-air temperature (in-compartment temperature) of the evaporator (6).

Then, the temperature sensors (Th1), (Th2), (Th
The detection signals of 3) and (Th4) are configured to be input to the controller (21), and the controller (21) includes an A / D converter (23) as shown in FIG. , An I / 0 port (24), a RAM (25), a ROM (26), and a CPU (27). Further, when the motor (MEV) of the electronic expansion valve (5) is in the refrigerating operation, each refrigerant temperature sensor (Th1), (Th1)
Based on the signal from 23), the opening is controlled by PID control so that the temperature difference between the outlet side refrigerant temperature and the inlet side refrigerant temperature becomes constant, while the opening side is controlled during the refrigerating operation. Expansion valve control means (12) that controls the opening by PID control so that the blown air temperature becomes a set value by the detection signal of the air temperature sensor (Th4), and the motor of the three-way proportional valve (2) during defrost operation (MV) for controlling the amount of hot gas flowing through the hot gas bypass line (9), capacity control means (14) for controlling the capacity of the compressor (1), and a storage It is provided with a desired internal temperature setting temperature input from the internal temperature setting device (22).

Further, (16) is an abnormality detecting means for detecting an abnormality of the refrigerant temperature sensors (Th1) and (Th2), and (17) is an expansion valve control means (1
2) Control means, wherein the first to fourth control changing means (171) to (174) according to claims (1) to (4) are incorporated in the controller (21), and based on the set temperature in the refrigerator. The controller (21) is provided with calculation means (271) for calculating the inlet side refrigerant temperature and the outlet side refrigerant temperature of the evaporator (6).

The first control change means (171) is configured such that the abnormality detection means (16) outputs an abnormality signal during the rapid freezing operation in which the set temperature in the refrigerator is set within a predetermined value or more by the setting device (22). When output, the opening valve control of the expansion valve (5) by the expansion valve control means (12) is configured to be changed to control based on the temperature difference between the set temperature in the refrigerator and the temperature of the air blown from the evaporator (6), The second control change means (172) is provided with the abnormality detection means (1) during the quick freezing operation in which the set temperature in the refrigerator is set within the range of less than a predetermined value by the setting device (22).
6) outputs an abnormal signal, the expansion valve control means (1
The control of the opening degree of the expansion valve (5) by 2) is changed to the control based on the temperature difference between the set temperature in the refrigerator and the blowout temperature of the evaporator (6).

Further, the third control change means (173) causes the abnormality detection means (16) to detect the inlet side refrigerant temperature sensor during the refrigerating operation in which the inside temperature is within a predetermined temperature range having a predetermined width with respect to the set temperature. When the abnormal signal of (Th1) is output, the opening control of the expansion valve (5) by the expansion valve control means (12) is performed by the refrigerant temperature of the outlet side refrigerant temperature detection means (Th2) and the calculation means (271). The fourth control changing means (174) is configured to change to control based on the calculated temperature, and during the refrigerating operation in which the inside temperature is within a predetermined temperature range having a predetermined width with respect to the set temperature, When the abnormality detecting means (16) outputs an abnormality signal of the outlet side refrigerant temperature sensor (Th2),
The control of the expansion valve (5) by the expansion valve control means (12) is configured to be changed to control based on the refrigerant temperature of the inlet side refrigerant temperature detection means (Th1) and the calculated temperature of the calculation means (271). ing.

Furthermore, in the third, (Tr) is a converter, (S) is a start / stop switch, (31) is a high pressure switch, (32) is a low pressure switch, and (33) is a hydraulic protection pressure switch. , (34)
Is a lamp switch, (35) is a hydraulic reset switch,
(36) is a compressor protection thermoswitch, (37) is for switching the transformer (Tr) connection, (38) is for voltage switching, (39),
Reference numeral (40) is a manual switching switch for the compressor motor, and the switches (37) to (40) are all interlocked.

(MC) is a compressor motor, and (10C) is a normally open contact (10C- ₁ ) that allows the blower fan motor (MF1) of the condenser (3) to be energized while operating the compressor motor (MC). )
Compressor relay having, (10F) is an evaporator (5) normally open contact to operate the blower fan motor (MF2) of _(10-1)
An evaporator fan relay having (20S- ₁ ) is a solenoid valve relay that allows or blocks the flow of the refrigerant in the refrigerant pipe.

Next, the control operation of the invention according to claims (1) and (2) will be described based on the control flow of FIG.

First, in step SA1, the temperature inside the refrigerator is rapidly cooled, then the flow proceeds to step SA2, and the abnormality detection means (16) determines whether or not the refrigerant temperature sensors (Th1), (Th2) are abnormal. Then, when normal, it stands by in step SA2 and continues to detect whether both refrigerant temperature sensors (Th1) and (Th2) are normal, and the expansion valve (5) has an inlet side and an outlet side of the evaporator (6). The expansion valve control means (12) controls the degree of opening based on the control value based on the refrigerant temperature difference between the internal combustion chamber and the internal combustion chamber to rapidly cool the inside.

On the other hand, if it is determined in step SA2 that there is an abnormality, the process proceeds to step SA3 and then to the setting means (22), where the set internal chamber temperature (SP) is a predetermined temperature, for example, -5.
℃ It is judged whether there is an abnormality.

Next, if the internal set temperature (SP) is set to -5 ° C or higher, the process proceeds to step SA4 and the blown air temperature sensor (Th
4) detects the blown air temperature of the evaporator (6) and then
In Step SA5, the control value changing means (171) obtains the temperature difference (ΔT) between the set temperature (SP) in the refrigerator and the blown air temperature (SS).

Next, in step SA6, control value changing means (171)
Based on the temperature difference (ΔT) of the expansion valve control means (12), the control right value of the expansion valve control means (12) is changed so that the temperature difference (ΔT) becomes a constant value. PID control of the opening in (5) is performed to continue the quick freezing operation.

Next, in the above step SA3, the set temperature in the refrigerator (SP)
Is lower than -5 ° C, the process proceeds to step SA7, the suction air temperature sensor (Th3) detects the suction air temperature of the evaporator (6), and then the process proceeds to step SA8, in which the control value changing means (172) is set. Find the temperature difference (ΔT) between the set temperature (SP) and the intake air temperature (RS). Next, at step SA9, the control value of the expansion valve control means (22) is changed so that the temperature difference (ΔT) becomes a constant value based on the temperature difference (ΔT) of the control value changing means (172). Expansion valve control means (12)
Performs PID control of the opening degree of the electronic expansion valve (5) to continue the quick freezing operation.

Next, the control operation of the invention according to claims (3) and (4) will be described based on the control flow of FIG.

First, in step SB1, if a freezing operation is performed in which the internal temperature is within a predetermined temperature range set in advance, the process proceeds to step SB2, and whether or not the inlet side refrigerant temperature sensor (Th1) is abnormal, specifically, The display can't really be a freezer. The abnormality detection means (16) determines whether the temperature is above + 80 ° C or below -80 ° C. Then, if normal, the process proceeds to step SB3, and similarly to step SB2, it is determined whether or not the outlet-side refrigerant temperature sensor (Th2) is abnormal, and if normal, the process returns to step SB2 and each sensor (Th1), (Th1), Th
The abnormality of 2) is continuously detected and the electronic expansion valve (5) is controlled by the output signals of both sensors (T1) and (Th2).

On the other hand, if the inlet side refrigerant temperature sensor (Th1) is abnormal, the outlet side refrigerant temperature To is obtained by the calculating means (271) by the CUP (27) in step SB2. Where To = SP-α + S
H is SP, SP is the set temperature in the compartment, α is the temperature difference between the refrigerant evaporation temperature in the evaporator (6) and the compartment temperature during steady operation in which the compartment temperature is within a predetermined temperature range, and SH is the evaporator ( 6) The degree of superheat of the evaporator (6) during steady operation, that is, the refrigerant temperature difference between the inlet and outlet of the evaporator, and the specific values of α and SH are calculated by the CPU (27) according to SP, etc. In this embodiment, S
When P is -12 ° C, α is 10 ° C and SH is 3-5 ° C.

Therefore, for example, the outlet side refrigerant temperature To = 19 ° C. to −17 ° C. is calculated.

Next, based on the third control changing means (173), the expansion valve opening control means (12) at step SB5 the deviation ΔT between the indication To 'and To of the outlet side refrigerant temperature sensor (Th2). After the calculation of the deviation ΔT
The opening degree of the electronic expansion valve (5) is PID-controlled so that becomes 0.

If not abnormal, the process returns to step SB1 and the same flow is repeated.

In step SB3, the outlet side refrigerant temperature sensor (T
If h2) is abnormal, the inlet side refrigerant temperature Ti is obtained by the CPU (27) in step SB7 as in step SB4. Here, Ti = SP−α, and in this embodiment,
If SP is -12 ° C, α is 10 ° C.

Next, under the instruction of the fourth control changing means (174), the expansion valve opening control means (12) determines in step SB8 that the indication Ti 'and Ti of the evaporator inlet refrigerant temperature sensor (Th1) are changed. Deviation ΔT
Then, in step SB9, the opening degree of the electronic expansion valve (5) is PID-controlled based on the deviation ΔT so that the deviation ΔT becomes zero.

Incidentally, the superheat degree SH in the present embodiment, the relationship between the temperature difference α between the inside temperature and the evaporator evaporation temperature of the evaporator and the inside set temperature SP,
The relationship between the blown air temperature SS or the intake air temperature RS and the set temperature SP in the refrigerator, and the control of the expansion valve opening for making the temperature difference ΔT 0 or a constant value are not limited to the present embodiment. Not a thing.

(Effect of the Invention) As described above, according to the inventions according to claims (1) to (5), when the refrigerant temperature detecting means on the outlet side or the inlet side of the evaporator is abnormal, a normal freezing temperature detecting means is provided. Alternatively, since the opening degree of the expansion valve is controlled by using the intake or outlet temperature detecting means of the evaporator, the opening degree of the expansion valve can be appropriately controlled, so that the refrigerating apparatus can be operated appropriately. be able to.

Therefore, in the present invention according to claim (1), for example, in the case of a refrigerating container, the temperature inside the refrigerator is lowered with reference to the temperature of the air blown from the evaporator, so that the articles inside the refrigerator are not damaged and the set temperature is set. Be dropped to.

Further, in the invention according to claim (2), since the internal cold storage temperature is lowered with reference to the intake air temperature of the evaporator, the frozen product in the cold storage is quickly exposed to the high temperature for a short time, and the set temperature is quickly set. Be dropped to.

In the invention according to claim (3) and call (4), not only the inside of the refrigerator can be held at the set temperature, but also the temperature of the evaporator can be appropriately held. The frost formation due to the shift of No. 2 is small, and consequently the temperature distribution of the air blown into the cold storage and the distribution of the temperature inside the cold storage can be maintained well.

Further, in the invention according to claim (5), the above effect can be obtained corresponding to each operating state.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. FIG. 2 is a refrigerant circuit diagram of an embodiment of the present invention, FIG. 3 is an electric circuit diagram,
4 and 5 are control flow charts. (1) …… Capacity control type compressor, (2) …… Three-way proportional valve,
(3) …… Condenser, (5) …… Electronic expansion valve, (6) ……
Evaporator, (8) ... Refrigerant circulation circuit, (12) ... Expansion valve control means, (A) ... Refrigerating device, (Th1) ... Inlet side refrigerant temperature sensor, (Th2) ... Outlet side refrigerant temperature Sensor, (Th
3) …… Suction air temperature sensor, (Th4) …… Blowout air temperature sensor, (12) …… Expansion valve, (16) …… Abnormality detection means,
(21) …… Controller, (22) …… Internal chamber temperature setter,
(171) to (174) ... control change means, (271) ... calculation means.

Claims (5)

[Claims] 1. A refrigeration circuit (8) comprising a compressor (1), a condenser (3), an expansion valve (5) with adjustable opening and an evaporator (6) connected in series in a closed circuit. In a refrigeration apparatus including: an inlet side refrigerant temperature detecting means (Th1) for detecting an inlet side refrigerant temperature of the evaporator (6); and an outlet side refrigerant temperature detected by an outlet side refrigerant temperature of the evaporator (6). Detection means (Th
2) and the outputs from both the refrigerant temperature detecting means (Th1) and (Th2), and the opening degree of the expansion valve (5) so that the temperature difference between the outlet side refrigerant temperature and the inlet side refrigerant temperature becomes constant. Expansion valve control means (12) for controlling the above, and the refrigerant temperature detection means (Th
(1), (Th2) at least one of the abnormality detection means (16) for detecting an abnormality and a setting means (2) for setting a desired internal temperature
2), a blown air temperature detecting means (Th4) for detecting the blown air temperature of the evaporator (6), and a rapid setting in which the set temperature in the refrigerator is set within a predetermined value or more by the setting means (22). During the refrigerating operation, when the abnormality detecting means (16) outputs an abnormality signal, the expansion valve control means (12) controls the opening degree of the expansion valve (5) and the blowing temperature of the evaporator (6). An operation control device for a refrigerating device, comprising: a control changing means (171) for changing to control based on a temperature difference from a temperature. 2. A refrigeration circuit (8) comprising a compressor (1), a condenser (3), an expansion valve (5) with adjustable opening and an evaporator (6) connected in series in a closed circuit. In a refrigerating apparatus including: an inlet side refrigerant temperature detecting means (Th1) for detecting an outlet side refrigerant temperature of the evaporator (6); and a refrigerant temperature detecting means for detecting an outlet side refrigerant temperature of the evaporator (6). (Th2)
And outputs from both of the refrigerant temperature detecting means (Th1) and (Th2), and controls the opening degree of the expansion valve (5) so that the temperature difference between the outlet side refrigerant temperature and the inlet side refrigerant temperature becomes constant. Expansion valve control means (12) and the refrigerant temperature detection means (Th
1), (Th2) at least one of the abnormality detection means (16) for detecting an abnormality, a setting means (22) for setting a desired internal temperature, and the evaporator (6) blow-in air temperature detection Intake air temperature detecting means (Th4) and the setting means (2
The abnormality detecting means (16) during the quick freezing operation in which the set temperature in the refrigerator is set within the range less than the predetermined value by 2).
Outputs an abnormal signal, the opening valve control of the expansion valve (5) by the expansion valve control means (12) is changed to control based on the temperature difference between the set temperature in the cold storage and the intake air temperature of the evaporator (6). An operation control device for a refrigeration system, comprising: a control changing means (172). 3. A refrigerant circulation circuit (8) comprising a compressor (1), a condenser (3), an expansion valve (5) with adjustable opening and an evaporator (6) connected in series in a closed circuit. In a refrigerating apparatus including: an inlet side refrigerant temperature detecting means (Th1) for detecting an inlet side refrigerant temperature of the evaporator (6); and an outlet side refrigerant temperature for detecting an outlet side refrigerant temperature of the evaporator (6). Detection means (Th
2) and the outputs from both the refrigerant temperature detecting means (Th1) and (Th2), and the opening degree of the expansion valve (5) so that the temperature difference between the outlet side refrigerant temperature and the inlet side refrigerant temperature becomes constant. An expansion valve control means (12) for controlling the above, an abnormality detection means (16) for detecting an abnormality of the inlet side refrigerant temperature detection means (Th1), a setting means (22) for setting a desired inside temperature, and Calculating means (271) for calculating the outlet side refrigerant temperature of the evaporator (6) based on the internal cold storage temperature set by the setting means (22)
When the abnormality detection means (16) outputs an abnormality signal during the refrigerating operation in which the temperature inside the refrigerator is within a predetermined temperature range having a predetermined width with respect to the set temperature, the expansion valve control means (12) causes A control changing means (173) for changing control of the expansion valve (5) to control based on the refrigerant temperature of the outlet side refrigerant temperature detecting means (Th2) and the calculated temperature of the calculating means (271). A characteristic operation control device for a refrigeration system. 4. A refrigerant circulation circuit (8) comprising a compressor (1), a condenser (3), an expansion valve (5) with adjustable opening and an evaporator (6) connected in series in a closed circuit. In a refrigerating apparatus including: an inlet side refrigerant temperature detecting means (Th1) for detecting an inlet side refrigerant temperature of the evaporator (6); and an outlet side refrigerant temperature for detecting an outlet side refrigerant temperature of the evaporator (6). Detection means (Th
2) and the outputs from both the refrigerant temperature detecting means (Th1) and (Th2), and the opening degree of the expansion valve (5) so that the temperature difference between the outlet side refrigerant temperature and the inlet side refrigerant temperature becomes constant. Expansion valve control means (12), an abnormality detection means (16) for detecting an abnormality of the outlet side refrigerant temperature detection means (Th2), a setting means (22) for setting a desired internal temperature, and Calculating means (271) for calculating the inlet side refrigerant temperature of the evaporator (6) based on the internal temperature set by the setting means (22)
When the abnormality detection means (16) outputs an abnormality signal during the refrigerating operation in which the temperature inside the refrigerator is within a predetermined temperature range having a predetermined width with respect to the set temperature, the expansion valve control means (12) causes A control changing means (174) for changing control of the expansion valve (5) to control based on the refrigerant temperature of the inlet side refrigerant temperature detecting means (Th1) and the calculated temperature of the calculating means (271). A characteristic operation control device for a refrigeration system. 5. A refrigerant circulation circuit (8) comprising a compressor (1), a condenser (3), an expansion valve (5) with adjustable opening and an evaporator (6) connected in series in a closed circuit. In a refrigerating apparatus including: an inlet side refrigerant temperature detecting means (Th1) for detecting an inlet side refrigerant temperature of the evaporator (6); and an outlet side refrigerant temperature for detecting an outlet side refrigerant temperature of the evaporator (6). Detection means (Th
2) and the outputs from both the refrigerant temperature detecting means (Th1) and (Th2), and the opening degree of the expansion valve (5) so that the temperature difference between the outlet side refrigerant temperature and the inlet side refrigerant temperature becomes constant. Expansion valve control means (12) for controlling the above, abnormality detection means (16) for detecting abnormality of the refrigerant temperature detection means, setting means (22) for setting a desired internal temperature, and the evaporator (6). Suction temperature detection means (Th3) for detecting the intake air and blown air temperatures of
And outlet temperature detecting means (Th4) and the setting means (22)
When the abnormality detection means (16) outputs an abnormality signal during the quick freezing operation in which the set temperature in the refrigerator is set within the predetermined value by the expansion valve (5) by the expansion valve control means (12). Opening control for the set temperature in the refrigerator and the evaporator (6)
Change to control based on the temperature difference from the blown air temperature of the first
When the abnormality detecting means (16) outputs an abnormality signal during the rapid freezing operation in which the temperature inside the refrigerator is set to a range below the predetermined value by the control changing means (171) and the setting means (22), the expansion Second control changing means (17) for changing the control of the expansion valve (5) by the valve control means to control based on the temperature difference between the set temperature of the internal cold storage temperature and the intake air temperature of the evaporator (6).
2), a calculating means (271) for calculating the refrigerant temperature on the inlet side and the outlet side of the evaporator (6) based on the set temperature inside the refrigerator set by the setting means (22), and the inside temperature is the set temperature. When the abnormality detection means (16) outputs an abnormality signal of the inlet side refrigerant temperature detection means (Th1) during the refrigeration operation within a predetermined temperature range having a predetermined width, the expansion valve control means (12) ) Control of the expansion valve (5) by the outlet side refrigerant temperature detecting means (Th2) and the calculating means (2).
A third control changing means (173) for changing the control based on the calculated temperature of (73) and the abnormality detection during the refrigerating operation in which the inside temperature is within a predetermined temperature range having a predetermined width with respect to the set temperature. The means (16) is an outlet side refrigerant temperature detecting means (Th2)
When the abnormal signal is output, the control of the expansion valve (5) by the expansion valve control means (12) is based on the refrigerant temperature of the inlet side refrigerant temperature detection means (Th1) and the calculated temperature of the calculation means (271). An operation control device for a refrigerating apparatus, comprising: a fourth control changing means (174) for changing to control.