Refrigerant leakage and detection

What is refrigerant

Refrigerant is also known as refrigerant, Freon, etc.; it is a working substance that circulates continuously in a refrigeration system and achieves refrigeration through changes in its own state. The refrigerant absorbs the heat of the cooled medium (water or air, etc.) vaporizes in the evaporator, and transfers the heat to the surrounding air or water and condenses in the condenser.

Industrial Infrared propane (Refrigerant) Sensor (6)
Industrial Infrared propane (Refrigerant) Sensor FS4NDIR/R290

Types of refrigerants

①. Inorganic compounds. Water, ammonia, carbon dioxide, etc.

②. Derivatives of saturated hydrocarbons, commonly known as Freon. Mainly methane and ethane derivatives. r22, r134a, etc..

③. Saturated hydrocarbons. Such as propane, isobutane, etc.

④. Unsaturated hydrocarbons. Such as ethylene, propylene, etc.

⑤. Azeotropic mixed refrigerants. Such as R502, etc.

⑥. Non-azeotropic mixed refrigerants. Such as R407c, R410, etc.

Industrial Infrared HFCs (Refrigerant) Sensor FS4NDIRR454B (6)
Industrial Infrared HFCs (Refrigerant) Sensor FS4NDIR/R454B

Refrigerant leakage and detection

1. Visual inspection:

Methods: When the refrigeration system leaks, it will be accompanied by the seepage of refrigeration oil. Using this feature, visual observation can be used to observe the entire refrigeration system of the outer wall, especially the welded parts and the evaporator surface with or without oil stains. If you suspect that the leakage is not obvious, you can put a clean white cloth, and gently press with your hand, if there are oil stains on the white cloth, indicating that there is a leakage.

Advantages and disadvantages: no cost can be checked by yourself; however, because the leakage is usually very subtle, and many parts of the refrigeration system are almost invisible. Unless the system suddenly breaks the big leak, and the system leaks liquid-colored media, otherwise the visual leak detection can not be located.

2. Bubble water or soapy water leak detection:

Methods: Soap water leak detection is to use a small brush dipped in pre-prepared soapy water, coated in the parts to be checked, and carefully observed.

Preparation of soapy water: available 1/4 piece of soap cut into thin slices, immersed in about 500g of hot water, stirring constantly to make it dissolve, after cooling the soapy water is condensed into a thick, light yellow solution. If you do not prepare good soapy water and the need, you can use a small brush dipped in more water, and stir in the soap into a foam, to be used after the disappearance of the foam.

Advantages and disadvantages: the method is simple and easy to use, and is also commonly used by maintenance workers to detect the method; but the human arm is limited, the range of human vision is limited, and many times can not see the leak.

3. Nitrogen water leak detection:

Method: fill the system with 10-20kg/cm2 pressure nitrogen, and submerge the system in water, the bubbling point is the leakage point.


The water used for leakage checking can easily enter into the system, resulting in corrosion of the materials in the system. It is very labor-intensive to carry out leakage detection.

4. Fluorescence leakage detection:

Method: add fluorescent agent into the system according to a certain proportion, put on special glasses after the system has operated for 20 minutes, irradiate the outside of the system with a leakage detection lamp, and the leakage place will be fluorescent in yellow.

Advantages and disadvantages: accurate positioning, the leakage point can be seen directly with eyes, and the maintenance cost is lower. The operation time is long, and the accuracy rate can not reach 100 percent;

5. Differential gas pressure leakage detection:

Method: Using the difference of gas pressure inside and outside the system, amplifying the pressure difference through the sensor to express the leakage detection result in the way of digital sound or electronic signal.

Disadvantage: This method can only “qualitatively” know whether the system is leaking or not, but can not accurately find the leakage point.

6. Halogen lamp leak detection:

Method: light the leakage detection lamp, holding the halogen lamp on the air tube, when the mouth of the tube near the leakage of the system, the flame color changes to purple-blue, that is, indicating that there is a large number of leaks here.

Disadvantages: this way there is an open flame, not only is it dangerous, but the combination of open flame and refrigerant will produce harmful gases, in addition, it is not easy to accurately locate the leak.

7. Electronic leak detector leak detection:

Electronic Refrigerant leak detection equipment is a reliable leak detector, because of its leak detection accuracy these years quickly occupied the market, the use of the probe against the possible leakage of the place to move, when the leak detection device issues an alarm, that is, indicating that there is a leak here. Leak detection with an electronic leak detector is the most scientific, simple, and fast leak detection method.