Comprehensive knowledge of air compressor oil

Comprehensive knowledge of air compressor oil

1. How is air compressor oil classified? Answer: According to the structure of the compressor, air compressor oil is divided into two types: reciprocating air compressor oil and rotary air compressor oil, each of which has three levels of light, medium and heavy load.

Air compressor oil can be divided into mineral oil compressor oil and synthetic compressor oil according to the type of base oil.

2. What kinds of oils are available for reciprocating air compressors? Answer: Reciprocating air compressor oil is divided into three types: light-duty L-DAA, medium-duty L-DAB, and heavy-duty L-DAC. The viscosity grades are all set to five grades of 32, 46, 68, 100, and 150, of which DAA, DAB is a mineral oil type, and DAC is a synthetic oil type.

2. What kinds of rotary air compressor oils are there?

Answer: Rotary air compressor oil is also divided into three types according to light, medium and heavy loads, namely L-DAG for light load, L-DAH for medium load, and L-DAJ for heavy load. The viscosity grades are set to 15 and 22. , 32, 46, 68, 100 six grades, among which DAG and DAH are mineral oil type, DAJ is synthetic type.

3. What is the function and main performance of air compressor oil?

Answer: Air compressor oil is mainly used for the lubrication of the moving parts of the compressor cylinder and the exhaust valve, and plays a role of rust prevention, corrosion protection, sealing and cooling. Since the air compressor is always in an environment with high pressure, high temperature and condensed water, the air compressor oil should have excellent high temperature oxidation stability, low carbon deposition tendency, suitable viscosity and viscosity-temperature performance, and good Oil-water separability, rust and corrosion resistance, etc.

4. What are the main types of synthetic air compressor oil? What are the advantages compared with mineral oil type?

5. Answer: The base oil used in synthetic compressor oil mainly includes synthetic hydrocarbon (poly-olefin), organic ester (diester), polyalkylene glycol, fluorosilicone oil and phosphate ester. Compared with mineral oil type, it has High temperature stability, not easy to form carbon deposits at high temperature, wide use temperature, low pour point, low volatility, long service life, etc., but because of the high price, it is only used for various harshness that mineral oil compressor oil cannot withstand Compressor under conditions.

6. Why must air compressor oil have good oxidation stability? What is the assessment method?

Answer: Because the air compressor oil is constantly in contact with high-pressure hot air in the cylinder, it is easy to cause oxidation and decomposition, and under the catalytic oxidation of metal wear debris, it aggravates the aging of the oil and generates various organic acids, Gum, asphaltene, etc., reduce the mechanical efficiency of the equipment, cause wear and tear, increase the temperature of the machine, and even cause a cylinder explosion. Therefore, air compressor oil must have good oxidation stability. The evaluation method is GB/T12709 lubricating oil aging characteristics measurement method and GB/T12581 steam turbine oil oxidation stability measurement method.

7. What is the main reason for the explosion of air compressor? How to prevent it? Answer: Air compressor oil with poor anti-oxidation stability is easy to produce sludge and carbon deposits, and air compressor oil with poor thermal stability is easy to decompose to produce light hydrocarbons and carbon dust, both of which cause air The main reason for the explosion of compressor oil. The substances that easily form carbon deposits in oils are mainly gums, asphalt and polycyclic aromatic polymers, which can be removed by deep refining. Therefore, air compressor oils are generally low-viscosity,

deep-refined, and do not contain the narrow fraction of heavy bright oil. That is, oils with low residual carbon value are used as base oils, and ash additives should be avoided as much as possible. To improve the oxidation stability and stability of the oil.

8. How to choose the viscosity of air compressor oil?

Answer: The choice of compressor oil viscosity mainly considers the discharge pressure, followed by the pressure ratio and discharge temperature.

9. What is the suitable compression medium for air compressor oil? Answer: The suitable compression medium for air compressor oil is air; various hydrocarbon gases (such as natural gas, petroleum gas, coke oven gas, ethylene, propylene, propane, etc.); inert gases (such as hydrogen, nitrogen, carbon dioxide, carbon monoxide, etc.) Argon, neon, helium, etc.); reactive gases (such as chlorine, hydrogen chloride, nitrogen oxide, sulfur dioxide, etc.)

10. What are the current domestic air compressor oil varieties? What are the specifications?

Answer: At present, the domestic standardized reciprocating air compressor oils are L-DAA and L-DAB. The specifications are GB12691-90, and the viscosity grades are equally divided into five brands: 32, 46, 68, 100, and 150.

Rotary air compressor oil has been standardized with L-DAG light-load injection rotary air compressor oil, the specification standard is GB5904-86, and the viscosity grades are 15, 22, 32, 46, 69, 100, and six brands; The L-DAH rotary screw air compressor oil standard is the corporate standard, with four grades of 32, 46, 32A, and 46A. DAH oil is a new type of high-quality screw air compressor oil prepared from hydrogenated base oil. Thermal oxidation stability and low carbon deposition tendency, of which 32A and 46A are anti-wear type.

11. What are the representative specifications of foreign air compressor oils? Answer: The representative specifications and standards of foreign air compressor oil are: German DIN51506 (my country GB12691 is formulated with reference to this standard), ISO/DP6521.3 (my country GB5904 is formulated with reference to this standard).

12. How is compressed gas oil classified?

Answer: ISO/DP6743/3 divides gas compressor oils other than air and refrigerant into five types according to their composition and characteristics, namely DGA (mineral oil type), DGB (specific mineral oil), KGC (common synthetic fluid), DGB (non-hydrocarbon synthetic fluid), DGE (commonly used synthetic fluid), among which DGA gas compressor oil is mainly used in N2, H2, NH3, CO2 compressors with pressure less than 100times; 105Pa, and He, Ar, SO2 under any pressure H2S compressor.

13. How to choose air compressor oil?

Answer: Choose the type of air compressor oil according to the design type of compressor oil, environmental conditions and operating load. Generally, under long-term high temperature environment (30℃), choose L-DAB oil, high speed water cooling or low pressure, small compression ratio The compressor can choose low-viscosity compressor oil. usually ①Air-cooled piston shaft output power; 20KW, select 32, 46, 100 (ambient temperature; -10℃ optional 32) DAA, DAB, DAC air compressor oil; ② Water-cooled piston type select 68 or 100 DAA oil; ③Drop oil rotary type to choose 100, 150, 220 DAB or DAC oil;

④ The oil injection rotary type selects No. 32 DAG, DAH or DAJ oil 14. What is the oil change index of the compressor?

Answer: Under normal circumstances, the compressor oil in operation should be sampled regularly to observe the color and cleanliness of the oil, and regularly analyze the physical and chemical properties of the oil viscosity, acid value, and n-pentane insolubles. If one of the following situations occurs, you should consider changing the oil. ① The oil has turned green, and the color number has deepened by 4 levels; ② The acid value exceeds 0.5mgKOH/g; ③ The viscosity change exceeds 15%; ④ The n-pentane insoluble matter exceeds 0.5%. The special oil change index for light-load oil-injected rotary air compressors is SH/T0538-93.