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Oil detection and analysis of variable frequency screw air compressor

2020-11-27 00:00:00

Screw air compressor oil monitoring technology content: The collected equipment lubricating oil or working medium samples are analyzed by optical, electrical, magnetic and other means to analyze their physical and chemical indicators, and detect the wear and contaminant particles carried, so as to obtain Information on the lubrication and wear status of the machine, qualitatively and quantitatively describe the wear status of the equipment, find out the inducing factors, evaluate the working condition of the machine and predict its failure, and determine the location, cause and type of the failure. Main physical performance indicators: viscosity, viscosity index, moisture, flash point, freezing point and pour point, mechanical impurities, insoluble matter, spot test, oxidation resistance, anti-emulsification, anti-foaming, anti-wear and extreme pressure properties .

Main chemical performance indicators: total acid value, total alkali value, corrosion resistance, rust resistance, chemical stability and additive element analysis.


Common concepts, methods and purposes of physical and chemical analysis.

(1) Viscosity

Basic concept: Viscosity is a measure of internal friction when a fluid flows. It is used to measure the ability of oil to resist flow at a specific temperature.

Detection method: Use a capillary viscometer to determine the kinematic viscosity of the oil. GB/T 265, ASTM D445 9

Test purpose: the main basis for the division of oil brand numbers

The main basis for oil selection

Important warning indicators for oil degradation "

Can judge the correctness of the oil

(2) Water content

Basic concept: refers to the percentage of water content in the oil (free water, emulsified water, dissolved water)

Detection method: the determination adopts distillation method; GB/T 260, ASTM D95

Test purpose: Moisture destroys the oil film, reduces lubricity, aggravates the wear of frictional parts, can react with oil, form acid, colloid and sludge. Water can precipitate additives in the oil, reduce the performance of the oil, and reduce the performance of the oil at low temperatures. The fluidity of the oil deteriorates, and the metal material of the equipment is corroded and rusted

(3) Flash point

Basic concept: the instantaneous flash temperature at which the oil escapes vapor under the specified heating conditions. :

Testing method: ASTM D92 GB/T 267

Test purpose: flash point can be used to judge the composition of oil fractions; flash point is a safety index of oil products;

The flash point can detect the light fuel oil mixed in the lubricating oil.

(4) Total acid value

Basic concept: the amount of acid needed to neutralize all the acidic components in 1g sample, and convert it into an equivalent amount of acid, expressed in mgKOH/g.

Detection method: color indicator method and potentiometric titration method.

GB/T 7304, ASTM D664

Test purpose: to judge the degree of refinement of the base oil;

Measurement of acidic additives in refined oil;

An important indicator of oxidative deterioration during the use of oil.

(5) Total base number

Basic concept: the amount of acid needed to neutralize all the alkaline components in 1g sample, and convert it into an equivalent amount of alkali, expressed in mgKOH/g.

Detection method: perchloric acid potentiometric titration method SH/T0251-1993, ASTMD2896 *

Test purpose: to reflect the amount of alkaline clean dispersion additives in internal combustion engine oil.

Monitoring the ability of alkaline additives to prevent oil oxidation

Detection of total base value of new oil

(6) Pollution degree analysis

Basic concept: Detect the size, quantity and distribution of pollutant particles in oil.

Detection method: automatic particle counting method (shading method)

Testing purpose: to quantitatively detect the quantity and pollution level of pollutant particles in lubricating oil;

For precision hydraulic systems, solid particle pollution will aggravate the wear of control components;

For turbine systems, solid particle contamination will aggravate the wear of bearings and other components

(7) Spectral element analysis

Basic concept: Detect the content of wear metals, pollution elements and additive elements in the oil in use.

Detection method: ASTM D6595 emission spectrometry (particle size <10um)

Test purpose: wear metal --- judge the wear of related parts of the equipment according to the composition and content trend of wear metal;

Pollution elements --- Judge the degree and cause of oil pollution;

Additive elements --- Judging the degree of loss of oil additives in the equipment.

(8) Ferrograph wear analysis

Basic concept: Detect the shape, composition, size and quantity of wear particles in the oil in use

Detection method: APTC/QTD-D01 magnetic field deposition, microscope analysis and judgment. .

Test purpose: analyze the shape of the wear particles and determine the type of abnormal wear of the equipment;

Analyze the size and number of wear particles to determine the degree of abnormal wear of the equipment;

Analyze the composition of the wear particles to determine the abnormal wear parts of the equipment

Quality assessment of lubricants:

Through the analysis and testing of various industrial lubricating oil physical and chemical indicators, according to the national and enterprise quality standards of lubricating oil, the quality of lubricating oil is evaluated, and the company is guided to choose high-quality and reasonable lubrication


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