Design And Research On Free-oil Scroll Air Compressor And Expander Unit

Scroll compressor with high compression efficiency, high reliability, low energy consumption, low noise, small vibration, compact structure, fewer parts and other outstanding advantages, is gradually used in various occasion demand compression. As the energy crisis, the haze and other environmental pollution problems occurred, the scroll expander which has a similar structure have been gradually concerned by scientists, and have been widely used in different areas.The paper analyzed the domestic and foreign scroll compressors, scroll expander and scroll compressor-expander unit, and according to the design specifications, design a oil-free scroll air compressor-expander unit. The unit can offer the oil-free pressure gas, at the same time, use the high-energy state exhaust gas to recover energy then it can reduce system power consumption.1. According to the system design requirements, it needs to provide oil-free high pressure air. It is true that oil-free air compressor can provide oil-free high pressure air without any other degreasing apparatus. Therefore, the machine used scroll profile to design, completing the program of oil-free scroll air compressor-expander unit, and determining the basic principles and structure modeling, using the scroll compressor and scroll expander share one orbiting scroll structure to reduce energy conversion chain and to improve the efficiency of energy recovery.2. According to design specifications of scroll compressor and scroll expander, the scroll compressor needs large gas displacement, small compression ratio. And in the same disc diameter, dual scroll profile can get higher gas displacement, small compression ratio, so scroll compressor design with dual scroll profile. However affected by the disc diameter orbiting scroll structure, the dual scroll profile expander would unable to complete a completion expander process. So the single scroll profile used in the scroll expander.Scroll top profile correction has a critical influence on the mechanical properties. Reasonable profile correction can improve the scroll mechanical gas displacement, compression ratio or expansion ratio. Dual scroll profile correction adopts the common correction method. Compare the PMP profile correction, the PMP plus line profile correction and the special correction method, single scroll top profile correction adopts the special correction to reduce the scroll expander inlet port power loss.3. According to the different design principle of scroll compressor and scroll expander, the paper completed the oil-free scroll air compressor-expander unit structural design parameters, and with the 3D software Solid works draw all 3D parts and assembly drawings, and put the key 3D parts into 2D machined drawings.4. Intake and exhaust set are very important in scroll machine, the degree of intake and exhaust optimization have directly affect on machine. According to the different feature of scroll compressor and scroll expander, design the different intake and exhaust to meet their needs. And each gas flow pulsations are analyzed, as well as do further research on intake power loss.