Explain the working principle of refrigerator compressor in detail, so that users can become experts.

The heart is the source of our human vitality. A strong heart can promote people's overall function. So is the refrigerator. As the heart of the refrigerator, the compressor determines the quality of a refrigerator. The quality of compressor plays a very important role in the performance optimization, efficiency improvement and noise level of refrigerator. Let me see how the refrigerator works. What is the working principle of the refrigerator compressor? How to simply distinguish the quality of compressor?

Working principle of refrigerator compressor

The refrigerator compressor is the heart of the refrigerator. It sucks in low-temperature and low-pressure refrigerant from the evaporator, drives the piston to compress the refrigerant to make it into high-temperature and high-pressure gas through the operation of the motor, and then sends the refrigerant to the refrigerator condenser through the conveying pipeline to provide sufficient power for the refrigeration system of the refrigerator to circulate, and finally realizes that the refrigerant changes from the compressor into high-temperature and high-pressure gas, condenses into high-pressure and low-temperature liquid through the condenser, and becomes low-temperature and low-pressure liquid through the capillary.

Boiling and vaporizing in the evaporator with equal pressure, absorbing heat from the surrounding medium into saturated low-temperature and low-pressure steam, and finally being absorbed by the compressor again, completing the cycle of the whole refrigeration system. Types of compressors for household refrigerators

At present, the compressors of household refrigerators and air conditioners are all positive displacement, which can be divided into reciprocating type and rotary type. Reciprocating compressor adopts piston, crank and connecting rod mechanism or piston, crank and sliding tube mechanism, and the rotating shaft adopts crankshaft mechanism.

According to the scope of application, it can be divided into low back pressure type, medium back pressure type and high back pressure type. Low back pressure type (evaporation temperature -35 ~- 15℃), generally used in household refrigerators, food freezers, etc. Medium back pressure type (evaporation temperature -20 ~ 0℃), generally used in cold drink cabinets, milk freezers, etc. High back pressure type (evaporation temperature -5 ~ 15℃), generally used in room air conditioners, dehumidifiers, heat pumps, etc.

The quality of the compressor determines the performance of a refrigerator. Therefore, it stands to reason that when you buy a refrigerator, you should carefully check the old and new compressor and its running state. But ordinary consumers don't know how to carry out professional testing, and many businesses are not allowed to carry out similar testing, so many consumers ignore this problem.

How to simply distinguish the quality of compressor

Check the old and new degree and state of the compressor from the appearance.

1: Refrigerator compressor with brand-new appearance, usually with smooth appearance, bright color and no roughness. The welded joints of the input pipe and the output pipe are directly welded with the evaporator at one time. If re-welded, there are usually polishing marks.

2. Date of production label: All new compressors have nameplates, indicating the compressor model, serial number, factory date, power size, etc. , can be checked.

3. Temperature: When the compressor is running, you can touch its shell with the back of your hand, and the shell should not be too hot. If it is too hot, it means that there is something wrong with the quality of this compressor, so you should buy it carefully.

4. Listen to the sound and simply check the quality of the compressor.

What are the normal noises?

(1) Jingle: When the running compressor stops running, it will produce this kind of jingle, sometimes it rings once, sometimes it rings twice, and the sound is loud. This noise comes from inside the compressor. The reason is that there are three springs hanging on the cylinder and stator in the compressor to prevent earthquakes. When the compressor stops working, there will be a resistance. Due to the action of the spring, the cylinder will swing to both sides, producing a metal impact sound, which is a normal noise.

(2) Click: After the compressor runs for a few minutes or stops for a few minutes, you can hear click, depending on which part of the refrigerator. If it is behind the refrigerator, it is usually condenser copper tube or louver fin.

Noise caused by thermal expansion and contraction, if this noise comes from the upper part of the refrigerator, it is usually the evaporator hoisted on the upper part of the refrigerator. Due to the change of temperature from cold to hot, the thin ice that has been frozen together in the hoisting part is cracked. Both of the above noises are normal. (3) Thunder: When the refrigerator is in use, whenever the compressor starts and stops, thunder is often heard in the tube, which is the sound of liquid refrigerant flowing. In the pressurized liquid pipeline, when the liquid flows, there is a rolling sound of water flow. This noise is very loud when the compressor starts and stops. For example, when the compressor is started, the liquid refrigeration is instantly impacted by high pressure, that is, when it starts to flow, the liquid flow rumbles, and once the liquid flow is stable, the noise is reduced; When the compressor stops running, the pressure decreases or disappears, but the flow of liquid can't stop for a while. Although the front wave slows down, the rear wave has a large inertia force and still rolls forward, making a rumbling sound, and then the sound disappears. This is a normal phenomenon.

What are the abnormal noises?

(1) Impact sound: When the compressor is running, there is a metal impact sound in the compressor, which is caused by the high-pressure silencing fracture in the compressor and often occurs in the use of refrigerators. This kind of sound requires cutting the casing, replacing the high-pressure muffler pipe or welding the damaged part.

(2) Thunder: When the compressor is running, there is thunder in the compressor. This kind of sound is the sound that the spring hanging steam in the compressor is broken or misplaced, which leads to the collision between the cylinder and the casing. This is an abnormal sound.

(3) Hum: One refers to the hum that the compressor is difficult to start after the power supply is turned on, because the power supply voltage is too high or too low, the heating wire of the overload protection relay is overheated, and the moving parts in the machine are stuck; The other is the hum of the pipeline hanging for too long without anti-vibration measures.

(4) Click sound: mainly because the pipes are close to each other, or the pipes are close to the refrigerator wall, the compressor will produce a click sound when running; In addition, loose screws can also produce this noise.

Editor's summary: The above is the working principle of refrigerator compressor, but the flow of liquid will not stop for a while. Although the front wave slows down, the rear wave has a large inertia force and still rolls forward, making a rumbling sound, and then the sound disappears. This is a normal phenomenon.

What are the abnormal noises?

(1) Impact sound: When the compressor is running, there is a metal impact sound in the compressor, which is caused by the high-pressure silencing fracture in the compressor and often occurs in the use of refrigerators. This kind of sound requires cutting the casing, replacing the high-pressure muffler pipe or welding the damaged part.

(2) Thunder: When the compressor is running, there is thunder in the compressor. This kind of sound is the sound that the spring hanging steam in the compressor is broken or misplaced, which leads to the collision between the cylinder and the casing. This is an abnormal sound.

(3) Hum: One refers to the hum that the compressor is difficult to start after the power supply is turned on, because the power supply voltage is too high or too low, the heating wire of the overload protection relay is overheated, and the moving parts in the machine are stuck; The other is the hum of the pipeline hanging for too long without anti-vibration measures.

(4) click: mainly because the pipes are close to each other, or the pipes are close to the refrigerator wall, the compressor will produce a click when it is running; In addition, loose screws can also produce this noise.

Editor's summary: The above is the working principle of refrigerator compressor.