How to select the lubricate oil type-- type of compressor and its lubrication requirements
Selection of lubricating oil for compressor
When the mechanical equipment is constantly improved, the lubricating oil as its "blood" must also adapt to the development pace. At this stage, mineral oil has not been able to adapt to more stringent conditions of compressor application, and synthetic compressor oil was born.
Generally, paraffin and naphthenic mineral oil are used as lubricants for compressors. In recent years, the material and design of compressors have been greatly developed, which provides increasingly stringent requirements for lubricating materials. Due to the mutual dissolution of mineral oil and hydrocarbon gas, resulting in viscosity loss; chemical feed gas carrying mineral oil into the processing process, resulting in catalyst poisoning; the formation of carbon deposits in the compressor of mineral oil, mineral oil has been unable to meet its use needs.
The performance of synthetic lubricating oil is better than that of mineral oil, such as high viscosity index, low pour point, prevention of hydrocarbon dilution, low volatility, good thermal stability, hydrolysis stability, demulsibility, chemical stability and compatibility with rubber and metal. The selection range of synthetic lubricants is wide, so it is necessary to investigate the characteristics of different synthetic oils to select the right lubricants for the improved compressor.
I. type of compressor and its lubrication requirements
According to the different ways of compressed gas, compressor can be divided into two categories: volume type and speed type. The positive displacement compressor depends on the reciprocating piston or the rotating rotor in the cylinder to change the gas volume, so as to compress the gas and increase the pressure. With the help of the high-speed rotating impeller, the speed compressor makes the gas obtain a very high speed, and then reduces the speed sharply in the diffuser, making the kinetic energy of the gas change into potential energy, that is, pressure energy.
According to their different structures and compressed gas modes, the two compressors can be divided into several types: Compressor - volume type - reciprocating type - piston type, diaphragm type, rotary type - leaf type, screw type, liquid ring type, rotor type, speed type - centrifugal type and axial flow type. In addition, according to different compression media and uses, compressors can be divided into two types: power compressors and process compressors. The former compressed medium is air, which is mainly used to drive pneumatic machinery, tools and materials transportation; the latter compressed medium is all gases, which is used for the compression and transportation of gases in the process flow.
At present, the widely used gas compressors are centrifugal, piston, vane, screw and so on. Because of the relatively harsh lubrication conditions, synthetic oil needs to be used. Some compressors with special gas medium also need to use synthetic oil with special performance.