JPH08145518A - Detecting device of quantity of refrigerant of air conditioning equipment - Google Patents

Abstract

PURPOSE: To detect correctly the insufficiency of a refrigerant in a refrigerant circuit even when the refrigerant and a refrigerating machine oil sealed in the refrigerant circuit separate into two layers. CONSTITUTION: A light-emitting diode 23 and a phototransistor 24 constituting a photosensor are provided at the back of sight glasses 21 and 22 respectively. When a specific condition determining means 29 determines that a refrigerant and a refrigerating machine oil are under the specific conditions of no opacity, on the basis of a refrigerant temperature detected by a temperature sensor 26 and a time passing from the start of operation of a compressor, which is detected by a timer 28, a check means 25 compares an output of the photosensor with a set value inputted from a setting means 18 and, when the former is smaller than the latter, it judges that the refrigerant sealed in a refrigerant circuit is insufficient and makes a display means 19 display the result of the judgement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner mounted on buses, trucks, passenger cars and the like.

[0002]

2. Description of the Related Art A refrigerant circuit diagram of a conventional air conditioner is shown in FIG.
Is shown in. When a running engine (not shown) rotates, the compressor 4 is passed through the pulleys 1 and 2 and the electromagnetic clutch 3.
Is driven. The gas refrigerant discharged from the compressor 4 enters the oil separator 15 via the discharge pipe 5, where the oil contained in the discharge gas is separated. The separated oil is returned to the compressor 4 via the oil return pipe 16.

The gas refrigerant flowing out of the oil separator 15 enters the condenser 6 where it is condensed and liquefied by radiating heat to the outside air blown by the fan 7. Next, this liquid refrigerant enters the expansion valve 11 via the receiver 9, dryer 10 and sight glass 17, and is adiabatically expanded by being throttled there. This refrigerant enters the evaporator 12 where it is
By cooling the air in the passenger compartment blown by 13, it is vaporized. Next, this gas refrigerant is sucked into the compressor 4 through the suction pipe 14.

[0004]

In the above-mentioned conventional air conditioner, it is possible to determine whether or not the liquid refrigerant is flushed through the sight glass 17, that is, by observing the amount of bubbles in the liquid refrigerant so that the inside of the refrigerant circuit is controlled. It was detecting whether the enclosed refrigerant was insufficient.

However, when the refrigerant enclosed in the refrigerant circuit is separated into two layers from the refrigerating machine oil, the refrigerant and the refrigerating machine oil are emulsified and become cloudy. Therefore, it is necessary to distinguish the cloudiness from the liquid refrigerant flush. There was a problem that I could not do it.

[0006]

The present invention has been invented to solve the above-mentioned problems, and the gist of the first invention is to provide a sight glass part in the liquid side pipe of the refrigerant circuit. In the provided air conditioner, a photosensor is installed in the sight glass part and a specific condition determining means for determining a specific condition in which the refrigerant and the refrigerating machine oil do not become cloudy, and the specific condition determining means determines that the specific condition is present. At this time, the refrigerant amount detection device of the air conditioner is provided with a check means for detecting the shortage of the refrigerant by comparing the output of the photo sensor with a set value.

The gist of the second aspect of the present invention is to provide an air conditioner having a sight glass portion in the liquid side pipe of a refrigerant circuit, wherein the sight glass portion is provided with a float that moves up and down due to the difference in density of the refrigerant. Along with this, there is provided a mark for judging whether or not there is a shortage of the refrigerant due to the movement of the float, in the refrigerant amount detecting device of the air conditioner.

[0008]

In the first aspect of the invention, when the specific condition determining means determines that the refrigerant and the refrigerating machine oil are in a specific condition in which the refrigerant and the refrigerating machine oil are not clouded, the checking means sets the output of the photosensor that has passed through the sight glass and the liquid refrigerant. The lack of refrigerant is detected by comparing with the value.

In the second aspect of the invention, whether or not the refrigerant is insufficient is determined by seeing through the sight glass and the relationship between the vertical position of the float and the mark.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A first embodiment of the invention is shown in FIGS. As shown in FIG. 1, sight glasses 21 and 22 are attached to the liquid refrigerant pipe 20 so as to face each other. A light emitting diode 23 is arranged behind the sight glass 21, and a phototransistor 24 is arranged behind the sight glass 22. The light emitting diode 23 and the phototransistor 24 constitute a photosensor.

The light emitted from the light emitting diode 23 passes through the sight glass 21 and the liquid refrigerant flowing through the liquid side pipe 20 and the sight glass 22, and is received by the phototransistor 24. The output of the phototransistor 24 is input to the checking means 25.

On the other hand, the temperature of the refrigerant detected by the temperature sensor 26 and the elapsed time from the start of operation of the compressor detected by the timer 28 are input to the specific condition judging means 29,
It is determined whether or not these are the specific conditions in which the refrigerant and the refrigerating machine oil stored in advance here are not clouded.

When the specific condition discriminating means 29 discriminates that the specific condition is present, it outputs it to the checking means 25. Then, the checking means 25 compares the output of the photosensor with the set value input from the setting means 18, and when the former is smaller than the latter,
It is determined that the flash, that is, the refrigerant is insufficient, and the determination result is output to the display means 19 and displayed here.

FIG. 2 shows a refrigerant (R134a) and a refrigerating machine oil (JE460P).
The critical solubility curve of A) is shown, A is a region where the refrigerant and refrigerating machine oil are completely dissolved at any ratio, B is a region where the refrigerating machine oil is dissolved, C is a region where the refrigerant is dissolved in the refrigerating machine oil, and D is This is a region where the refrigerant and the refrigerating machine oil do not dissolve in each other but separate into two layers and coexist.

On the other hand, when the compressor is stopped for a long time, the refrigerant and the refrigerating machine oil are separated into two layers, and immediately after the start of operation, these become an emulsion and become cloudy. Therefore, a predetermined time, for example, 10 minutes has elapsed after the start of operation. Otherwise, this cloudiness will not disappear.

However, when the temperature and the oil concentration of the refrigerant are in regions other than D shown in FIG. 2 and 10 minutes have passed after the start of the operation of the compressor, that is, under the specific condition that the refrigerant and the refrigerating machine oil are not clouded. At one time, if the output of the photo sensor is less than or equal to the set value, it can be determined that a large amount of bubbles are contained in the liquid refrigerant and a so-called flash is occurring, that is, the refrigerant in the refrigerant circuit is insufficient. . Therefore, even when the refrigerant and the refrigerating machine oil are separated into two layers, the shortage of the refrigerant sealed in the refrigerant circuit can be accurately detected and the fact can be notified.

In the above embodiment, the temperature of the refrigerant is input to the specific condition discriminating means 29. However, instead of the temperature of the refrigerant, information indicating this indirectly, for example, the temperature of the condenser, the discharge of the compressor, etc. It is possible to input the pipe temperature, the number of revolutions of the compressor, the high pressure and the low pressure of the refrigerant circuit, and the like.

A second embodiment of the invention is shown in FIG. The tubular housing 30 is arranged horizontally, and both ends thereof are connected to the liquid side pipe 20 by welding 36.
A sight glass 32 is tightly fitted on one side surface or both side surfaces of the enlarged portion 31 formed in the center of the housing 31, and a mark 39 is provided on the sight glass 32.

A float 34 is provided in the enlarged portion 31, and a wire is provided in a through hole 35 formed in the float 34.
33 is inserted. The wire 33 extends vertically, and both ends thereof are inserted into holes 37 formed in the upper surface and the lower surface of the enlarged portion 31 and fixed by welding 38.

Although the liquid refrigerant flows through as shown by the white arrow, when the number of bubbles in the liquid refrigerant increases, the density of the liquid refrigerant decreases, and the float 34 moves downward accordingly. Then, when the lower end of the float 34 contacts the mark 39, it is determined that the refrigerant in the refrigerant circuit is insufficient.

[0021]

According to the first aspect of the present invention, when the specific condition determining means determines that the refrigerant and the refrigerator hydraulic pressure are under the specific condition in which the refrigerant and the refrigerator are cloudy, the output of the photo sensor that has passed through the sight glass and the liquid refrigerant is checked. The lack of the refrigerant can be detected by comparing the set value with the means. Therefore,
Even when the refrigerant enclosed in the refrigerant circuit and the refrigerating machine oil are separated into two layers, it is possible to accurately detect whether or not the refrigerant in the refrigerant circuit is insufficient.

In the second aspect of the invention, the shortage of the refrigerant can be determined by seeing through the sight glass and seeing the relationship between the vertical position of the float and the mark. As a result, not only the same effect as the first aspect of the present invention can be achieved, but also under the condition that the refrigerant and the refrigerating machine oil are emulsified and cloudy, the lack of the refrigerant enclosed in the refrigerant circuit can be accurately detected. it can.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a critical solubility curve of a refrigerant and a refrigerating machine oil.

FIG. 3 is a vertical cross-sectional view showing a second embodiment of the present invention.

FIG. 4 is a refrigerant circuit diagram of a conventional air conditioner.

[Explanation of symbols]

 20 Liquid side piping 21, 22 Sight glass 32, 24 Photo sensor

Claims (2)

[Claims] 1. In an air conditioner having a sight glass portion provided in a liquid side pipe of a refrigerant circuit, a photosensor is installed in the sight glass portion and a specific condition determining means for determining a specific condition in which the refrigerant and the refrigerating machine oil are not clouded. And an air conditioner characterized by comprising check means for detecting a shortage of the refrigerant by comparing the output of the photosensor with a set value when it is determined that the specific condition is determined by the specific condition determination means. Refrigerant amount detection device. 2. An air conditioner in which a sight glass portion is provided in a liquid side pipe of a refrigerant circuit, wherein the sight glass portion is provided with a float that moves up and down due to a difference in density of the refrigerant and the movement of the float causes a shortage of the refrigerant. A refrigerant amount detection device for an air conditioner, which is provided with a mark for determining the presence or absence of the refrigerant.