4. Oil-gas lubrication method: Use a quantitative piston to intermittently spit out a small amount of lubricating oil, and the mixing valve slowly introduces the lubricating oil into the compressed air, and uses the air to continuously flow the oil. Advantages: The oil supply is small and can be quantitatively managed, suitable for high-speed rotation, low heat generation, low pollution to the surrounding air, and new lubricating oil is often delivered without worrying about oil deterioration. Disadvantages: Special oil-gas lubrication equipment is required, and maintenance is more complicated. Application: Suitable for occasions where the bearing runs at a high speed, and is generally less used in the oil refining and chemical industry.

5. Oil spray lubrication method: Use a high-pressure spray method to spray the lubricating oil into the bearing to lubricate the bearing. Advantages: Less oil pollution, long lubrication time, and no need for frequent replacement and replenishment. Disadvantages: High oil quality requirements and high maintenance costs. Application: Commonly used for bearings on vertical or inclined shafts and high-speed operation. For high-speed operation accompanied by centrifugal force, the lubricating oil injection speed is required to be no less than 15m/s.