JPH0526446Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to refrigeration equipment such as air conditioners, water coolers, and transportation units for freezing and refrigeration.

(Prior art and its problems) In this type of refrigeration system, when it is installed, the amount of refrigerant charged in the refrigerant circuit may be too much or too little.
Air in the refrigerant circuit may not be completely exhausted. Furthermore, during operation of the refrigeration system, refrigerant may leak from the refrigerant circuit or air may enter the refrigerant circuit.

However, conventional refrigeration equipment does not have a function to self-determine whether there is an abnormality in the refrigerant system, such as an excess or deficiency of refrigerant in the system, or air contamination. Judgments were made based on whether the condition was good or whether the high and low pressures in the refrigerant circuit were significantly different from standard values.

(Means for solving the problem) The present invention was proposed to solve the above problem, and its gist is that the refrigerant is removed from the compressor, condenser, throttle, evaporator, etc. In a refrigeration system that radiates heat to the outside air in the condenser and cools a controlled object in the evaporator, a control temperature sensor detects the temperature of the controlled object, and the outside air detects the outside air temperature. A temperature sensor and a high pressure sensor for detecting the high pressure of the refrigerant circuit are provided, and when the temperature of the controlled object detected by the control temperature sensor is at a preset diagnostic temperature, the temperature detected by the outside air temperature sensor is By comparing the outside air temperature and the high pressure detected by the above-mentioned high pressure sensor with preset abnormality judgment criteria, it is determined whether there is an abnormality in the refrigerant system such as excess or deficiency in the amount of refrigerant in the system, or air contamination, and an alarm is issued. A refrigeration system is characterized in that it is equipped with a control device that outputs.

(Function) Since the present invention has the above configuration, when the temperature of the controlled object reaches the preset diagnostic temperature, the detected outside air temperature and high pressure are compared with the preset abnormality judgment criteria. By doing so, it is possible to diagnose whether there is an abnormality in the refrigerant system and issue an alarm.

(Example) Hereinafter, the present invention will be specifically described with reference to illustrated embodiments.

FIG. 1 shows a system diagram.

The high-temperature, high-pressure refrigerant gas discharged from the compressor 1 enters the condenser 2 as shown by the arrow, where it is condensed and liquefied by radiating heat to the outside air sent by the fan 3. Next, after being reduced in pressure by being throttled as it flows through the throttle 4, it enters the evaporator 5, where the air in the freezer sent by the fan 6 is cooled, evaporated, and compressed. Machine 1
Return to

A high pressure sensor 7 is attached to the refrigerant pipe on the discharge side of the compressor 1, and the high pressure detected by the high pressure sensor 7 is input to the control device 10.
An outside air temperature sensor 8 is installed in the intake air flow of the condenser 2.
is installed, and the outside air temperature detected by this outside air temperature sensor 8 is input to the control device 10. In the suction air stream of the evaporator 5 there is a temperature of the object to be controlled, i.e.
A control temperature sensor 9 is installed to detect the temperature of the air inside the freezer, and the control temperature detected by the control temperature sensor 9 is input to the control device 10. Note that the high pressure sensor 7 may be attached to the refrigerant pipe on the outlet side of the condenser 2.

FIG. 2 shows a control block diagram, and FIG. 3 shows a control flowchart.

2 and 3, when a diagnosis start signal is input from the switch 19 to the control means 16 of the control device 10, the control means 16 controls the operation command means 17.
A signal to start operation is sent to the compressor 1, fans 3 and 6, and at the same time, the timing means 15 starts operating.
A timer is set. The control temperature detected by the control temperature sensor 9 is input to the comparison means 11,
Here, it is compared with the diagnostic temperature preset in the diagnostic temperature setting device 12. When the control temperature reaches the diagnostic temperature, the control means 16 determines whether the time set in the timer means 15, that is, the predetermined time required for the refrigerant system to stabilize from the start of operation, has elapsed;
If the specified time has not passed, "Diagnosis not performed"
A signal is sent to the display driving means 18, and the display 20 thereby displays "diagnosis not performed". Furthermore, if a predetermined time has elapsed, a diagnosis is performed. That is,
When the control temperature reaches a predetermined diagnosis temperature, the control means 16 instructs the high-pressure pressure diagnosis means 14 to perform diagnosis. Then, the outside air temperature detected by the outside air temperature sensor 8 and the high pressure detected by the high pressure sensor 7 are inputted to the high pressure pressure diagnosis means 14, and the high pressure and the high pressure detected by the outside air temperature input from the abnormality judgment criterion setting device 13 are inputted to the high pressure diagnosis means 14. It is compared with the abnormality judgment criteria. Based on the comparison result, a display signal such as "high voltage is low", "normal", or "high voltage is high" is sent to the display signal driving means 18, and the display 20 displays this.
Note that the diagnostic temperature is selected from a typical temperature commonly used in refrigeration equipment, for example, a set temperature in a freezer. Furthermore, the abnormality judgment criteria are set through tests and calculations by keeping the control temperature constant and varying the outside air temperature and refrigerant charging amount as parameters.

FIG. 4 is a diagram for explaining the concept of criteria for determining normality/abnormality. As shown in FIG. 4, the high pressure changes in response to changes in the outside air temperature and the amount of refrigerant charged under conditions where the control temperature is constant. That is, even if the amount of refrigerant charged is appropriate, as the outside air temperature increases, the condensation temperature increases, so the high pressure also increases like the c line. When the amount of refrigerant charged is greater than the appropriate amount of refrigerant, even if the outside temperature is the same, the high pressure is higher than when the amount of refrigerant is appropriate, as shown by the d-line and the e-line. As the amount of refrigerant charged increases, the amount of liquid refrigerant held in the condenser 2 increases and its effective heat exchange area becomes smaller, so the outside air temperature rises above a certain temperature, that is, above point g on the e line. If this happens, the compressor 1's protector, high pressure protection switch, etc. will operate, making it impossible to continue operation. Conversely, if the amount of refrigerant charged is less than the appropriate amount of refrigerant, the high pressure becomes lower than when the amount of refrigerant is appropriate, as shown by line b and line a. When the amount of refrigerant charged decreases, the amount of refrigerant circulating in the refrigerant circuit becomes insufficient and the cooling capacity decreases.If the outside air temperature exceeds point f on line A, the cooling load becomes greater than the cooling capacity, making it impossible to maintain the control temperature. It disappears. Based on the above, the abnormality judgment criterion is set as a high pressure range in which the refrigeration system can normally operate within the outside temperature range in which it is operated, that is, a range from the b line to the d line. Alternatively, it can be set as the high pressure when the amount of refrigerant is appropriate, that is, the pressure shown by line c, plus some positive or negative allowable pressure. Further, by setting such an abnormality determination criterion, even if air is mixed into the refrigerant circuit, the high pressure becomes abnormally high, so that it is possible to determine an abnormality.

(Effects of the invention) In the present invention, a control temperature sensor that detects the temperature of a controlled object, an outside temperature sensor that detects the outside air temperature, and a high pressure sensor that detects the high pressure of the refrigerant circuit are provided, and the control temperature sensor When the temperature of the controlled object detected by is at a preset diagnostic temperature, the outside air temperature detected by the outside air temperature sensor and the high pressure detected by the high pressure sensor are used as a preset abnormality judgment criterion. By comparison, we have installed a control device that determines whether or not there is an abnormality in the refrigerant system, such as an excess or deficiency of refrigerant in the system, air intrusion, etc., and issues an alarm, so even when the refrigeration equipment is in operation, no measuring equipment or operations can be performed. It is possible to automatically know whether there is an abnormality in the refrigerant system without the need for In addition, when the temperature of the controlled object is at a preset diagnostic temperature, that is, the temperature of the controlled object is kept constant and the outside air temperature and high pressure are compared with preset abnormality judgment criteria, so the refrigerant system The presence or absence of an abnormality can be accurately determined.

As a result, it becomes easier to discover abnormalities in the refrigerant system, and it also becomes easier to maintain and manage the refrigeration system.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a system diagram, FIG. 2 is a control block diagram, FIG. 3 is a control flowchart, and FIG. 4 is an explanatory diagram of abnormality judgment criteria. Compressor...1, Condenser...2, Throttle...4, Evaporator...5, Control temperature sensor...9, Outside temperature sensor...8, High pressure sensor...7, Abnormality standard setting device... 13. Diagnostic means...14.

Claims (1)

[Scope of utility model registration request] In a refrigeration system in which the refrigerant circulates through a refrigerant circuit consisting of a compressor, a condenser, an aperture, an evaporator, etc., heat is radiated to the outside air in the condenser, and the object to be controlled is cooled in the evaporator. A control temperature sensor for detecting the temperature of the outside air, an outside air temperature sensor for detecting the outside air temperature, and a high pressure sensor for detecting the high pressure of the refrigerant circuit are provided, and the temperature of the controlled object detected by the control temperature sensor is set in advance. When the temperature is at the diagnostic temperature, the outside air temperature detected by the outside air temperature sensor and the high pressure detected by the high pressure sensor are compared with preset abnormality judgment criteria to determine whether the amount of refrigerant in the system is too much or too little. A refrigeration system characterized by being equipped with a control device that diagnoses the presence or absence of an abnormality in a refrigerant system such as contamination of refrigerant and issues an alarm.