A lot of copies are broken by an explanation of the principle of making cold, but today they decided to send another army. Perhaps, they will not pass the material in vain, efforts in vain. The principle of operation of the refrigerator is based on the ability of freon to easily change the state of aggregation, giving, taking heat. This class of substances was not always used. Used ammonia and other aggressive media. In the 1930s, freons, relatively safe for humans, and effective, were discovered. As a result, the other is forgotten today, refrigerants are called digits, marked with the prefix R. Today the world develops isobutane, the concentrations of workers are small, the security for the ozone layer is great. True, the substance is explosive. Discuss the principle of operation of the refrigerator.
How the refrigerator
works Let's start the discussion of the principles of operation of the refrigerator by the compressor. A heart! The main thing here. The motor of the refrigerator usually costs asynchronous, therefore, a start-up relay is often required for operation. The responsibility of the device is to connect the start winding, only at the time of launch. The internal bimetallic plate is heated, the capacitor is disconnected from the starting winding, the only working one is functioning. Over-heating protection works according to a similar system: the refrigerator engine runs for too long, the thermal effect of the current unbends another bimetallic plate, tearing the contact, allowing the windings to rest.
Such a scheme will allow the refrigerator to work efficiently, will provide a good starting point. It is clear that inside the device freon, which is not that with pleasure circulating around the contour, the piston requires some effort. Here, remember:
The motor is withdrawn from the refrigerator - the start-up relay is included. You can not take another relay, another engine, with a high degree of probability disrupts the normal operation, sooner or later causes the combustion of the windings.
Refrigerator motors have individual starting requirements. Power is also different, therefore, the type, heating of the bimetallic plate of the relay does not remain constant. Special reference books have been written, where we will see which refrigerator motors are, what types of relays correspond. By the way, they laid out a list on the site, we hope, pleased the readers. Modern refrigerator engines have inverter control, the crankshaft no longer contain. The linear motion of the shaft, stuck with wits called epithet compressors.
Inside there is a coil, equipped with a core, moving progressively according to the law of alternating current supplied to the wire. Despite the seeming awkwardness( similarity with electric shavers) motors, as practice shows, maximally meet the goals. In addition, inverter control is most effectively implemented, helping to reduce noise and prolong life. No wonder Samsung gives 10 years warranty on the motors of refrigerators. Recall:
- Asynchronous motors with a squirrel-cage rotor can change the rotational speed, including those controlled by varying the frequency of the supply voltage.
- Collector motors, rarely used in refrigerators, are deprived of this ability.
- A new type of motor from a coil and an oscillating core is also easily controlled by changing the pulse frequency.
The result is the following circuit:
- The input voltage is rectified.
- Is cut with a power key with the desired duration.
- The work is filled with a clock pulse generator.
The simplest circuit, rather related to a pulsed power supply, is the same as before: there is a voltage of 50 Hz, then it becomes a voltage of another frequency. As a result, we see a change in the speed of movement of the piston, which is why freon begins to move acceleratedly, slowly. What does this give?
The heart pumps blood, the compressor is freon. Meaning: it is required to create high pressure on the condenser( on the back wall of the refrigerator), low on the evaporator. As a result, the refrigerant starts to liquefy on the first one, and the second one actively evaporates. In the first case, a large amount of heat is released, which goes to the kitchen, in the second case, the energy confiscated from the refrigerator compartment is absorbed. As a result, the refrigerator freezes. The blood moves faster, the health of a person is more vigorous, the difference in pressure drops is greater than the condenser-evaporator, more cold, which means the compressor will have to sweat.
refrigerator So, we have shown the dependence of cold output on the speed of the compressor, now consider the method of obtaining the pressure difference. You know, YouTube is spinning a roller: a man in fins masters a water stadium. Runs far enough from the coast. The speed of running is the first factor, the second we call the increased footprint. In the refrigerator, the situation is similar. Frisky torsion of the rotor of the engine freon powerless to provide the desired pressure difference. Powerless directly - it helps an important addition to the veins of the coolant circulation, a capillary tube. The course is very thin, set after the condenser. As a result, the pressure here quickly grows, freon at once becomes a liquid. Instantly gives energy. Formed the principle of operation of the refrigerator.
Some heat is collected by the evaporator. Do not believe it, even water evaporates in a vacuum, ice evaporates. .. sublimation. A similar process takes place behind the back wall of the freezer( cold store), where a vacuum is created by the compressor. Liquid freon gradually flows through the capillary tube and disappears. Even at a low temperature that prevails in the evaporator, it manages to select the heat of the frozen metal. In this regard, it is time to mention one detail, without which the device of the refrigerator is incomplete in any way. Filter drier( sometimes called receiver).
Filter drier of the
refrigerator So, we see high temperatures near the condenser - water quickly becomes steam. Where it comes from in the freon circuit remains a mystery even for the masters, but it is known for certain: without liquid, half of the refrigeration repairmen will lose their jobs.
Useful liquid, trying to leave the capillary tube, forms an ice block, tightly blocking the operation of the unit. If you remember, the pressure on this side is low, the vacuum cannot penetrate the growth of crystals of frozen moisture.
As a result, it turns out that the compressor is working to its fullest, the pressure difference between the condenser and the evaporator is incredible, the point is zero, the freon does not circulate. There is no one to transfer heat from place to place.
A characteristic feature of the malfunction in this case is that the malfunction disappears if you turn off the refrigerator for a while. Then the collision begins again. Caused by the fact that the cork melts, growing again. Therefore, the filter drier is working near the condenser, take more water. Inside is a trivial silica gel, familiar to many by shoes, clothes. Bags filled with balls that collect moisture. Gradually, the filter drier produces a resource, water vapor continues to treat the freon circuit of the refrigerator. By the way, when refilling the part is subject to mandatory replacement.
The filter drier looks like a thickening of the copper tube, which is impossible not to notice. However, often covered with a layer of polyurethane foam. In this case, the details need to be broken. It all depends on the type of refrigerators. However, a complex system would be a pile of iron, do not exist thermostat, measuring the conditions of the chambers, issuing a command on and off the compressor.
Typically, a thermostat is built on the basis of pressure measurement. It is clear that the cold air is heavier, therefore, it is possible to determine whether the membrane is pressing enough. Access to the sensing element is through a tube. Screw tightens the tension of the membrane. As a result, we get such small “pocket watches” that have a long tube instead of a chain. The excess cut is laid between the walls, the intake hole is held in the working chamber.
Modern thermostats are much more primitive. A sad thermocouple, depending on the size of the EMF, what the electronic board of the refrigerator will do at the next moment. Understandably, such a scheme, unlike the previous one, requires power, which somewhat complicates the adjustment process. But the repair turns into real entertainment: the main thing is to find a thermocouple with suitable characteristics, it is not necessary to tear half the refrigerator to pull the tube. Simplifies the life of masters.
Finished the story about how the refrigerator works, mentioned aspects of the device device.