JPH09196524A - Trouble diagnostic device of refrigerating equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To diagnose the presence of troubles in a liquid injection circuit, and a solenoid valve, a capillary tube, etc., mounted on the liquid injection circuit of a refrigerating equipment where a compressor, a condenser and an evaporator are connected together in this order to form a refrigerant circuit, and the refrigerant circuit includes the liquid injection circuit which is equipped with a solenoid valve and through which a portion of liquid refrigerant condensed at the condenser is led to the compressor. SOLUTION: When an diagnostic instruction is output from a PTI instruction switch, an operating instruction device 22 of an diagnostic device 20 starts a compressor 1 to begin the operation of a refrigerating machine at the same time a solenoid valve 8 is opened. After a specified period of time T1 set in a timer 23 elapses, the solenoid valve 8 is closed. On the other hand, after the specified period of time T1 elapses, a memory 24 stores the temperature of delivery gas of the compressor 1 detected by a sensor 11. A differential temperature calculating device 21 calculates a differential temperature between the temperature detected by the sensor 11 when a specified period of time T2 passes after the solenoid valve 8 is closed and the temperature stored in the memory 24. A judging device 26 compares the differential temperature calculated with a specified value input from a data memory 27, and judges it normal when it is the specified value or larger and judges it abnormal when it is not exceeding the specified value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure diagnosis device suitable for a refrigeration system for containers.

[0002]

2. Description of the Related Art A system diagram of this type of refrigerating apparatus is shown in FIG. An air circulation fan 5 for air circulation and an evaporator 4 for air cooling are arranged in an air flow passage 9 formed in the container C in which air inside the container circulates.

When the refrigeration system is operated, the gas refrigerant discharged from the compressor 1 enters the condenser 2 where it is condensed and liquefied. This liquid refrigerant enters the expansion means 3 composed of an electronic expansion valve and the like, and is throttled here to adiabatically expand to become a gas-liquid two-phase refrigerant. The refrigerant returns to the compressor 1 after being evaporated and vaporized by cooling the in-compartment air blown by the fan 5 while passing through the evaporator 4.

When the solenoid valve 8 interposed in the liquid injection circuit 6 is opened when the load increases, the condenser 2
A part of the liquid refrigerant condensed in 1. is injected into the liquid injection circuit 6, and the solenoid valve 8 and the capillary tube 7 interposed therein.
And is injected into the compressor 1 to prevent the temperature of the compressor 1 from rising.

[0005]

The above-mentioned conventional refrigeration system checks the presence / absence of abnormality in the pre-operation inspection of the container, but has a problem that it cannot diagnose the presence / absence of failure of the liquid injection circuit 6. .

[0006]

The present invention has been invented to solve the above-mentioned problems, and its gist is to connect a compressor, a condenser, an expansion means and an evaporator in this order. In a refrigerating device provided with a liquid injection circuit for introducing a part of the liquid refrigerant condensed in the condenser into the compressor in the refrigerant circuit formed by, and a solenoid valve provided in this injection circuit, the discharge gas of the compressor A temperature detecting sensor is provided and a diagnostic command is issued to open the solenoid valve to operate the refrigeration system. After a predetermined time from the diagnostic command, operation command means to close the solenoid valve and the sensor to detect the predetermined time are detected. And a temperature difference between the temperature detected by the sensor when the set time elapses after the solenoid valve is closed and the temperature stored in the storage unit. A failure of the refrigerating apparatus, which is provided with a diagnostic device including a temperature difference calculating unit that determines whether the calculated temperature difference is a predetermined value or more and a determination unit that determines an abnormality when the calculated temperature difference is a predetermined value or less. In the diagnostic device.

When the diagnosis command is output, the operation command means opens the electromagnetic valve to operate the refrigerating device, and closes the electromagnetic valve after a predetermined time. The discharge gas temperature of the compressor detected by the sensor after the predetermined time is stored in the storage means, and the temperature detected by the sensor when the set time has elapsed after the electromagnetic valve is closed and the temperature stored in the storage means. The difference is calculated by the temperature difference calculating means. The determination means determines that the calculated temperature difference is normal when the temperature difference is equal to or larger than a predetermined value, and abnormal when the calculated temperature difference is equal to or smaller than the predetermined value.

Display means may be provided for displaying the abnormality when the above-mentioned determination means determines that it is abnormal.

[0009]

1 and 2 show an embodiment of the present invention.
FIG. 1 is a system diagram, and FIG. 2 is a control flowchart. As shown in FIG. 1, a sensor 11 for detecting the discharge gas temperature is attached to the discharge pipe of the compressor 1.
The detected temperature of 11 is input to the temperature difference calculating means 21 of the diagnostic device 20.

When the diagnostic command from the PTI command switch 12 is input to the operation command means 22, the operation command means 22 causes the solenoid valve 8 to operate.
To start the operation of the refrigeration system by outputting it to the compressor 1 and opening it.
Then, when the predetermined time T ₁ set in the timer 23, that is, the time required for the operating state to stabilize, has passed, it is output again to the solenoid valve 8 to close it.

The sensor 11 when the predetermined time T ₁ has elapsed
The detected temperature is stored in the storage means 24. After the solenoid valve 8 is closed, when the set time T ₂ set in the timer 25, that is, the time required for the operating state to stabilize, the temperature difference calculation means 21 detects the temperature detected by the sensor 11 and the storage means 24. The temperature difference from the temperature stored in is calculated.

The calculated temperature difference is input to the determination means 26, and the determination means 26 determines that the temperature difference is normal when the temperature difference is equal to or more than the predetermined value input from the data storage means 27 and abnormal when the temperature difference is less than the predetermined value. When it is determined to be abnormal, the display means 13
And output it to.

The predetermined value is the pressure of the high pressure refrigerant,
It is obtained from the correlation between the refrigerant temperature at the outlet of the evaporator 4 and the temperature of the air blown out from the evaporator 4, and is stored in the data storage means 27.

If the liquid injection circuit 6 is normal, the solenoid valve 8 is opened and the compressor 1 is operated for a predetermined time T ₁
When operated, a part of the liquid refrigerant condensed in the condenser 2 is partially injected into the liquid injection circuit 6, the solenoid valve 8 and the capillary tube 7.
The temperature of the gas discharged from the compressor 1 is lowered by being injected into the compressor 1 through the gas.

After that, when the electromagnetic valve 8 is closed and T _{2 is} operated for a predetermined time, the liquid refrigerant is not injected into the compressor 1 and the temperature of the discharged gas rises. Therefore, the temperature difference between the discharge gas temperature when the solenoid valve 8 is opened and the discharge gas temperature when the solenoid valve 8 is closed becomes large.

However, if the liquid injection circuit 6 is abnormal, the liquid refrigerant is not injected even if the electromagnetic valve 8 is opened, the injection amount is too small, or the liquid refrigerant is injected even if the electromagnetic valve 8 is closed. Therefore, the temperature difference between the discharge gas temperature when the solenoid valve 8 is open and the discharge gas temperature when the solenoid valve 8 is closed becomes small.

Therefore, by comparing this temperature difference with the predetermined value stored in the data storage means 27, it is possible to determine whether the liquid injection circuit 6 is normal or not. In addition to this, it is possible to check whether the refrigerant pipe is erroneously connected to the compressor 1.

[0018]

In the refrigerating apparatus of the present invention, when a diagnostic command is output, it is possible to automatically diagnose the presence or absence of a failure in the liquid injection circuit by the diagnostic apparatus.

When the determination means determines that the abnormality is present, if a display means for displaying the abnormality is provided, the failure of the liquid injection circuit can be easily corrected, so that the failure of the compressor due to the failure of the liquid injection circuit can be prevented. It can be prevented.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a control flowchart of the embodiment.

FIG. 3 is a system diagram of a conventional refrigeration system.

[Explanation of symbols]

 1 Compressor 2 Condenser 3 Expanding means 4 Evaporator 6 Liquid injection circuit 8 Solenoid valve

Claims (2)

[Claims] 1. A liquid injection circuit for introducing a part of the liquid refrigerant condensed in the condenser into the compressor in a refrigerant circuit formed by connecting a compressor, a condenser, an expansion means and an evaporator in this order. , In a refrigeration system provided with an electromagnetic valve in this injection circuit, a sensor for detecting the discharge gas temperature of the compressor is provided and the refrigeration system is operated by opening the electromagnetic valve according to a diagnostic command, and the predetermined time of the diagnostic command is reached. The operation command means for closing the solenoid valve later, the storage means for storing the temperature detected by the sensor after the predetermined time, and the temperature detected by the sensor when the set time after closing the solenoid valve has elapsed. A temperature difference calculating means for calculating a temperature difference between the temperature stored in the storage means, and a normal temperature when the calculated temperature difference is a predetermined value or more, and an abnormality when the calculated temperature difference is a predetermined value or less. Failure diagnosis apparatus of a refrigeration apparatus, characterized in that a diagnostic device comprising a determination unit. 2. A display means for displaying the abnormality when the determination means determines that the abnormality is present.
A failure diagnosis device for the refrigeration system described.