Refrigeration compressors can be divided into two types: semi-hermetic and fully hermetic refrigeration compressors according to their structural methods.
1. Environmental test chamber fully enclosed refrigeration compressor
Fully enclosed refrigeration compressor advantage:
The refrigeration compressor and motor of the environmental test chamber are installed in a shell that is welded or brazed, and share a main shaft. This not only eliminates the shaft seal device, but also greatly reduces the size and weight of the entire compressor. Exposed on the surface of the casing are only welded suction and exhaust pipes, process pipes and other necessary pipes (such as spray pipes), input power terminals and compressor brackets.
Shortcoming:
Since the entire refrigeration compressor motor unit is installed in a sealed casing that cannot be disassembled and is difficult to open for internal repairs, this type of refrigeration compressor is required to have high reliability and long life, and the installation requirements for the entire refrigeration system are also High, this fully enclosed structure is generally used in mass-produced small cooling capacity refrigeration compressors.
2. Environmental test chamber semi-hermetic refrigeration compressor
Environmental test chamber semi-hermetic refrigeration compressors mostly adopt the integral structure of cylinder block and crankcase, and the motor casing is often an extension of the cylinder block crankcase to reduce the connection surface and ensure the concentricity between the compressor stage motors; In larger models, they are made separable for the convenience of casting and processing, and are connected by flanges at the joints. The two spaces of the crankcase and the motor room are connected by holes to facilitate the return flow of lubricating oil. The main shaft of the semi-hermetic refrigeration compressor is a crankshaft or an eccentric shaft; some use air or water to cool the built-in motor, and some use inhaled low-temperature working fluid vapor. For semi-hermetic compressors in the small power range, centrifugal oil supply is often used for lubrication.
This lubrication method has a simple structure, but when the compressor power increases and the oil supply is insufficient, it is changed to the pressure lubrication method.
Environmental test chamber semi-hermetic refrigeration compressor advantage:
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Can adapt to a wider pressure range and cooling capacity requirements
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The thermal efficiency is high and the unit power consumption is low. Especially the existence of the air valve makes the deviation from the design operating conditions more obvious;
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The material requirements are low, and ordinary steel materials are mostly used, which are easier to process and the cost is relatively low;
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It is technically mature and has accumulated rich experience in production and use;
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The installation system is relatively simple.
