How to lubricate and dissipate heat from an oil-free compressor

The oil-free lubrication compressor realizes lubrication and heat dissipation in an oil-free environment through special design, and its core methods are as follows:

1. lubrication method

1. water lubrication technology
   • principle: Replace lubricating oil with water, and realize the four functions of lubrication, cooling, sealing and noise reduction through water film. The water forms a uniform water film during the compression process, which covers the surfaces of moving parts such as rotors and bearings, reducing direct metal contact and reducing wear.
   • Advantage:
     • zero oil pollution compressed air completely free of oil, in line with the food, pharmaceutical and other industries CLASS 0 standards.
     • Environmental protection: The discharge water can be directly discharged or recycled without special treatment.
     • Efficient sealing: The water film fills the mechanical gap to prevent air leakage and improve compression efficiency (the amount of air discharged is 25% more than that of the dry screw).
   • Application Scenarios water lubricated single screw compressor is widely used in food processing, pharmaceutical, electronic manufacturing and other fields requiring high purity gas.
2. Material self-lubricating and special design
   • self-lubricating material some compressors use anti-wear materials such as polytetrafluoroethylene (PTFE) and graphite to make piston rings, sealing packings or bearings, and use the low friction characteristics of the material itself to reduce wear.
   • Gap design: Through precision machining to ensure that the rotor and the housing, the rotor to maintain a small gap (such as oil-free screw compressor rotor gap control in 0.01-0.05mm), to avoid direct contact, while the use of gas pressure to achieve sealing.
   • synchronous gear: The dry screw compressor drives the male and female rotors through synchronous gears to ensure that the rotors rotate without contact and further reduce wear.

2. heat dissipation mode

1. water cooling system
   • water jacket cooling: A water jacket is installed outside the cylinder or compressor shell to absorb the heat generated during compression through circulating cooling water. For example, oil-free lubrication screw compressor in the cylinder outside the water jacket, the use of water specific heat capacity, good thermal conductivity characteristics, quickly take away heat.
   • water film heat dissipation: In the water-lubricated compressor, the water film not only lubricates, but also directly absorbs the heat generated by the friction of the parts, realizing the dual functions of lubrication and heat dissipation.
2. air cooling and structural optimization
   • fin heat dissipation: Some oil-free compressors (such as oil-free models transformed from oil-injected lubricated compressors) are equipped with fins outside the cylinder to accelerate heat dissipation by increasing the heat dissipation area.
   • runner design: Optimize the air flow channel inside the compressor, such as setting a special flow channel to guide the air flow to take away heat. For example, a patented technology through the design of the flow channel between the cylinder and the connecting body, so that the air flow from the air outlet to take away the heat of the cylinder and the motor housing, improve the heat dissipation efficiency.
   • Heat absorption ring and heat conducting rod: The high-efficiency oil-free scroll compressor uses a heat absorption ring to absorb internal heat, and then transfers the heat to the heat sink through a heat conducting rod to achieve rapid cooling.
3. isothermal compression design
   • due to the cooling effect of water, the compression process of water-lubricated compressor is close to isothermal compression (temperature rises slowly), which significantly reduces energy consumption and heat generation compared to adiabatic compression (temperature rises sharply), and reduces heat dissipation requirements from the root.