【 Weak current College 】 refrigeration compressor works on

Refrigeration compressor is a core part of the air conditioning system, usually known as refrigerator host. Scientific and technological progress, new air conditioning system, promoted the refrigeration compressor manufacturing technology continues to progress. From current trends in the refrigeration compressor, compact, energy-efficient, as well as micro-vibration characteristics of low noise is the air conditioning compressor manufacturing technology constantly pursuit of goals. Following on the refrigeration compressor do an overview.
Role:
L, from the evaporator steam suction m to ensure the evaporator pressure within a certain amount of evaporation;
2, higher pressure (compressed) in order to create at a high temperature condensation conditions;
3. transportation of refrigerant, the refrigerant complete refrigeration cycle.
First, there are many kinds of compressors, according to the works, the air conditioning compressor can be divided into fixed displacement compressor and variable displacement compressor.
L, fixed displacement compressor for exhaust volume, with the engine's speed increases in proportion to the increase, it cannot under refrigeration needs automatic change of power transmission and engine oil consumption of relatively large. Its control normally through acquisition evaporator outlet temperature signal, when the temperature reaches the set temperature, the compressor stops working; when the temperature rises, the compressor start T II. Fixed displacement compressor was also affected by the air conditioning system pressure pipeline control, when the pressure is too high, the compressor stops working.
2. variable displacement compressor can set temperature automatically adjust the power output. Air-conditioning control system does not capture the evaporator outlet temperature signal m, but according to the air conditioning pipe pressure change signal to control the compressor automatically adjust compression ratiothus m air temperature. The whole process of the refrigeration, the compressor has always been in the works, the regulation of refrigeration and intensity depend entirely on the compressor's internal pressure control valve to control. When the air conditioning pipe inner high-pressure side pressure too high, the pressure control valve shorten compressor in piston stroke to decrease the compression ratio, which reduce the strength of refrigeration. When the high-side pressure drop to a certain extent, low-voltage-side pressure up to a certain extent, is increasing the pressure regulating valve piston stroke to improve refrigeration strength.
Second, according to the working methods of different,
Can be divided into two categories: volume type and speed.
Volume compressors by working cavity volume changes to achieve suction steam, compressed, exhaust, etc. Belong to this type of compressor with reciprocating compressors and rotary compressor. Speed type compressor by high-speed rotating T for I1 "work on steam, pressure, and complete the task of conveying of steam. Belong to this type of compressor with centrifugal and axial flow compressors, centrifugal compressor is commonly used. 1, reciprocating compressor works
Reciprocating compressor also known as the piston compressor. Compressor working cavity is the cylinder. Piston in the cylinder for upper and lower reciprocating motion, thus completing the compression and exhaust, expansive, steam, etc. Figure 1 the four process represent a compressor 1 second in four processes.
To the lowest position (called the piston down only point), cylinder suction full steam. While the Pistons move up, then suck, exhaust doors are closed, cylinder volume, steam is compressed and has been compressed into the exhaust pressure is reached. Diagram (b) to exhaust process: when the pressure reaches a certain value (greater than the pressure in the exhaust pipe), exhaust valve opening, Pistons continue to move up, vapor discharge until the piston moves up to the highest position (the position that the piston TDC), exhaust end. (C) in the diagram is clearance expansion process: in order to prevent the piston and suction steam valves, piston moves up to the top point, the top of the piston and the cylinder with a certain gap between that clearance. When the piston turn down motion, leave at the end of the exhaust in the clearance of the high pressure steam stop smoking steam steam suction valve opening, cannot start. When the clearance of steam with the expansion of the piston down, has been expanded to suction steam pressure below. Diagram of (d) is the process of steam absorption: absorption steam valve opening, with the piston downward movement and suction steam, has been carried out to the piston down to piston bottom stop point.
(2) benefits: its broader application, manufacturing technology, mature, simple structure, but also for the processing of materials and processing requirements lower lT arts, the cost is relatively low, adaptable, able to adapt to the wide pressure range and refrigeration capacity requirements can be maintained.
(3) disadvantage: can't achieve high speed, large, heavy machinery, not easy to achieve lightweight, exhaust air flow is not continuous, but prone to fluctuations in work have higher vibration. Due to the crankshaft and connecting rod compressors of the above characteristics, has very few small compressor using this structure, the crank-connecting rod compressors are mostly used in passenger cars and trucks of large displacement air conditioning system.
2. screw compressors of structures and work process
Screw compressor is a rotary positive displacement compressors. It leverages the volume and the screw slot location changes to complete the vapour inhalation, compression and exhaust IqJ process. Oil free screw compressors in the 1930s, primarily used for compressed air. Later, cylinder injection screw compressors, performance is improved, at present, injection-type screw compressor is the main machines in the refrigeration compressors. Screw compressor consists of twin screw and single-screw, two-screw compressor customarily called the screw compressor.
(1) in Figure 2-injection type screw compressors. In the section for double circle intersecting hood is equipped with a pair of rotor and rotor-Yang and Yin rotor. Yang rotor has four teeth, Yin rotor has six teeth, two rotor mutual engagement. Dangyang rotor rotation for a week, hidden rotor rotation 2/3 weeks, or rather, Yoko speed than the speed of the rotor Yin Fast 50 per cent. Figure 3 is a screw compressor from suction steam by exhaust work process at the suction vapour-seat open mouth with suction steam, steam when the alveolar and suck, suck mouth with steam begins to, with the screw rotation, alveolar detachment suction steam vents, an alveolar spaces suction full steam, as in figure (a). Screw continue to rotate, two screw gear meshing with alveolar mutual, cylinder block, meshing of screw and exhaust-side seat composed of alveolar volume smaller, and the location to move the exhaust tip, completed a vapor compression and transmission, as in Figure
(b)。 When the alveolar spaces and the end of the exhaust
EstuarySame time, compression, vapour exhaust ended, as in figure (c). Each pair of alveolar spaces there smoke steam,
Compression and exhaust three procedures. At the same time there are suction steam, compressed, exhaust three process, but
They occur in different alveolar spaces.
(2) screw compressors of advantages:
① screw compressor only rotation, not reciprocating motion, therefore the balance good compressor, small vibration, you can increase the compressor speed.
② screw compressors of simple structure, compact, light weight, non-smoking, exhaust valve, few wearing parts, high reliability, long life cycle maintenance.
③ in low evaporation temperature or high compression mode, use the single-stage compression can still be working, and have good performance. This is because there is no screw compressor clearance, no smoking, exhaust valve, so in such adverse conditions still has high volumetric efficiency.
④ screw compressor is not sensitive to wet compressed.
⑤ screw compressors for refrigeration capacity to 10 per cent of a 100 percent stepless adjustment, but 40 percent load regulation more economical.
(3) bad: noise is large, and the need to set
Reset a lubricating oil separation, cooling, filtration and compression of auxiliary equipment, resulting in a unit volume.