Compressor oil change a lot of knowledge fully explored

In the context of the compressor oil change scientific standard to explore exchange system on the oil standard, in fact, in addition to standard oil change, there are a lot of knowledge about compressor oil change, learning to master these oil change will benefit.

1, the necessity of compressor oil change

Compressor oil in use process, by heating, oxidation, high speed shearing, the effect of dust pollution and harmful gas. Oxygen and lubricating oil hydrocarbons in reaction, make the oil oxidation, color black, viscosity rise slowly, and finally may seriously to oxide can’t dissolve in oil, but in brown mucous layer deposition somewhere in the system, easy to plug components of the control oil duct, make the ball bearing, valve core, such as friction losses increase, affect the normal operation of system. Oxidation corrosion may be created and acidification. Oxidation process is started slowly, the accumulation of sediment and acid value increased, the viscosity increased, to a certain extent, it should be an oil change. Otherwise, oxidation, oxidation rate gradually speeding up, the viscosity will follow up, as a result, working oil temperature rise high. With continuous reinforcement, oxidation of compressor oil viscosity will appear obvious rising trend. When the oxidation rate from linear to power curve, the viscosity rise faster, may appear people don’t want to see the results.

2, the temperature of the compressor oil

Under atmospheric pressure, lube oil oxidation process is very slow, so in storage and transportation, the lubricating oil is not easy to oxidation. But when the temperature of the lubricating oil or oxygen pressure rises, the lubricating oil oxidation rate increased rapidly.

Centrifugal compressor piston compressor cycle of lubricating oil and lubricating oil relationship between temperature and the temperature of the compressed gas is not big, but is different screw compressor, the compressor oil temperature in the exhaust temperature of the compressor and lubricant between the temperature changing after cooling. In most of the time, the temperature of the compressor oil is equal to and close to the main engine exhaust temperature. The life of the injection screw compressor oil by thermal oxidation effect is much more strongly.

3, real life of compressor oil

The service life of screw air compressor oil should be under normal working condition of the minimum service life, it is difficult to accurate determination of the use of lubricating oil cycle, each manufacturer is different also, the general rule is: Ⅰ class mineral oil for 2000 hours, Ⅱ class mineral oil to 4000 (later reduced to 2000) hours, Ⅲ class mineral oil to 6000 (later reduced to 4000) hours, PAO to 8000 (6000) also have considered hours, polyol ester to 12000 (8000) also have considered hour.

Is the life of the compressor oil lubricating oil manufacturers, rotating bomb method is used to test the oxidation stability of less than 50 min, below 50 min oxidation accelerated began (oil change standard general for 60 min), argues that the life of the compressor oil. Different kinds of compressor oil life difference is quite big, its oxidation stability depends on the nature of the base oil and formula.

Good Ⅲ part oil and PAO, ester oil compressor oil life can reach 5000 ~ 5000 hours (air compressor exhaust pressure of 0.7 ~ 0.8 MPa), the acid value is 2.0 mgKOH/g time 10000 hours or more, rotary oxygen bomb value of up to 1500 ~ 2000 min. Notice here "life can reach 5000 ~ 5000 hours" and "10000 hours" or two data, looks depending on some contradictions, later will be discussed further.

3.1 type compressor oil

Compressor oil varieties more, now of the compressor oil base oil alone: mineral oil, secondary hydrogenation mineral oil, hydrogenated heterogeneous Ⅲ base oil, natural gas synthetic Ⅲ base oil and PAO, polyether, ester oil, including (double ester and polyol ester), silicone oil and so on.

Sold in compressor oil has ordinary compressor oil (mineral oil as base oil, synthetic oil and semi synthetic oil. Of synthetic oil is relatively chaos, synthetic oil by chemical synthesis method of base oil, a shell called the hydrogenation of heterogeneous Ⅲ class base oil: XHVI synthetic oil of high viscosity index, the base oil is the depth of the mineral oil refining processing, more wonderful is to use natural gas synthetic GTL Ⅲ class base oil.

As for semi synthetic compressor oil has been confused, semi synthetic oil is for pure mineral oil is difficult to meet the conditions of the compressor, the special structure of synthetic oil by adding some targeted to improve some aspects of function, is a kind of not only ensure performance and minimize the cost increase of technical solutions. Half the performance of synthetic oil is not a simple average synthetic oil and mineral oil properties, choose reasonable semi synthetic oil allocation can sometimes get the unexpected performance.

The problem is that the semi synthetic oil, mineral oil base oil content is how much? The type and content of synthetic oil? Because Ⅲ type of base oil are unconventional base oil, the part of Ⅲ type of base oil is mineral oil through hydrogenation of heterogeneous formation, with synthesis gas is a part of the GTL Ⅲ class base oil. In recent years, people put Ⅲ class base oil and mineral oil, synthetic oil and other is called Ⅲ kind of oil, the term is appropriate, reasonable, meaning clear.

3.2 a great relationship with the compressor compressor oil of real life

As the result of lubricating oil manufacturers propaganda, users not know compressor itself to compressor oil, especially the injection screw air compressor oil the influence of the real life, the truth is: even if is the same kind of compressor oil used in different types, different parameters, the compression medium and condition of the compressor, real life is quite different. See the following analysis:

1) if the injection screw air compressor exhaust temperature lowering of 8 ~ 10 ℃, the service life of compressor oil will be doubled;

2) single-stage injection screw compressor exhaust pressure from 0.3 ~ 1.3 MPa, because of the exhaust gas temperature and oxygen partial pressure, air compressor oil oxidation speed, exhaust pressure of 0.3 MPa of low-pressure air compressor lubricants real life than the exhaust pressure of 1.3 MPa compressor increases 3 ~ 5 times;

3) nitrogen compressor lubricants are not affected by the effect of oxygen than real life increase a lot of the same kind of air compressor;

4) compressed CO2 gas similar screw compressor oleic acid value is higher, the real life is short;

5) two stage compression of atmospheric pressure injection screw air compressor because of low oxygen points at all levels, low exhaust temperature not only high efficiency, and lubricating oil real life more than the single stage compressor same type 2 times;

6) high compression ratio of single stage compressor oil screw air compressor is shorter;

7) frequency injection screw air compressor in the variable frequency during exhaust temperature is low, the compressor shearing action of lubricating oil lighter than normal capacitors adjustable air compressor, oil real life is long, frequency conversion time and frequency conversion depth is different, the real life of different lubricating oil;

8) some air compressor manufacturers and users in order to improve the energy efficiency, increase the air injection screw air compressor fan, reduces the exhaust temperature of screw compressor, this not only reduces the power consumption, and prolong the service life of the compressor oil, achieve the result of kill two birds with one stone.

9) centrifugal compressor oil and piston compressor oil real life much more than the captain of the injection screw air compressor.

4, oil change standard

In the compressor oil change scientific standard to explore "the article says: the appearance of the compressor oil change oil standard for sludge, precipitation is more, the color black, emulsified oil change should be considered.

Quantitative description should be:

1) color change is greater than 3;

2) the kinematic viscosity (100 ℃) rate was 20% (3) compressor oil change oil acid value appreciation is limited to greater than 100% is relatively appropriate;

4) light load injection rotary air compressor oil oil change standard SH/T 0538 is about pentane insolubles, % is greater than 2.0;

5) light load injection rotary air compressor oil oil change standard SH/T 0538 on oxidation stability (rotary oxygen bomb), e. 60 min;

6) oil change standard iron/mu (g/g) for 200;

7) oil change/standard silicon content of 50 mu (g/g) regulations.

In these indicators, the kinematic viscosity should be first. Compressor oil viscosity changes, the user can self-test or entrusted test, larger companies may have lubricant viscosity meter, can test yourself; General user might as well take a sample or entrust the local technical supervision inspection bureau have kinematic viscosity tester units for testing.

5, product selection reference

Usually can choose Ⅲ oil, oil Ⅲ antioxidant capacity measured by the rotary oxygen bomb results is Ⅱ class 6 ~ 7 times of base oil. Imagine their lives than the average is given priority to with Ⅱ class base oil of the life of the compressor oil is much longer.

On the basis of Ⅲ oil, oil and PAO and esters, portfolio, equipped with a super antioxidant, anti-friction and anti-wear additive such as fixing agent of ultra-high performance compressor oil qualified for more than 90% of the energy efficient air compressor.

6, timing of oil change,

6.1 and the simple floating time and time

1) oil suppliers will tell users a service life of the compressor oil, part of the user is actually according to the supplier recommended lubricating oil life, fixed oil change time.

Too many problems here: compressor oil supplier did not promise him the use of the compressor oil temperature and the corresponding service life; Different compressor oil with different base oil and additives, life difference is very big. The author in this paper, 2015 7 issue of the domestic long life compressor oil present situation and the development, the article has done, but because of space, the discussion of this problem is real.

Including Ⅰ, Ⅱ, Ⅲ, Ⅳ class the work of the compressor oil temperature above 60 ℃, each additional 8 ~ 10 ℃ its service life will be halved, which work at 90 ℃ is the life of compressor oil at 80 ℃ for 50% of the working life.

2) when buying compressor oil compressor users, should be clear for the use of the compressor oil temperature and the corresponding life. So, compressor users can work in accordance with the compressor oil temperature and the life of the relationship, based on the practical working temperature of the compressor flexible, the service life of the compressor oil using floating - doing so is a scientific, economic, reliable and practical.

7, the way of an oil change

If at the time of the compressor oil change, dirty oil or spent oil cleaning not clean, the new added to the compressor oil will be affected by pollution, has introduced a large number of free radicals, the role of accelerated oxidation, the result is a newly added to the life of the compressor oil will be reduced by half. This is tantamount to put just burn a pot of good dishes to have rotted leftovers containers, flavor changed, all dishes deteriorate faster.

In order to get good oil change effect, the following countermeasures to choose from:

Game 1: serious cleaning oil, pipeline and oil cooler. When an oil change, put clean the spent oil, first in components in oil and gas separator, carefully cleaning the oil and gas separator shell; Circumstances to determine whether to purge oil cooler, oil change again after cleaning.

Strategy 2: in 3 to 5% of the old oil cleaning agent added to the compressor, under normal working condition of 6 ~ 24 hours after the operation, will be all clean oil discharge system, after replacing oil filter and oil and gas separator element, add a new compressor oil boot can normal operation. Such as system due to the use of mineral oil or poor quality oil sludge or carbon deposit for a long time did not clean, can be appropriate to extend the time of cleaning, is 2 ~ 3 days, has no effect on the system. Such as cleaning out a large number of oil sludge and carbon deposition during or after a colloidal suspension of filter clogging up, may cause the system to jump machine, the need to replace the new filter cleaning.

Strategy 3: with the compressor spent oil, add 5 # spindle oil, low voltage operation 5 ~ 10 minutes after release (clean), add new compressor oil. The release of spindle oil safekeeping (appropriate USES five gallons of water storage in plastic drum, next time, when using can remove sediment), supplies of oil change with. Don’t have to worry of spindle oil low flash point, low viscosity of spindle oil flow is big, exhaust temperature is low, and the high rate of washing, easy rinse;

Strategy 4: with the compressor spent oil, add 5 # spindle oil, low voltage operation 5 ~ 10 minutes after release (clean), using compressed air or bottled nitrogen blow pipe line, including oil cooler and oil and gas separator, after being blown clean, add new compressor oil.

Five countermeasures: conditional user can connect higher levels of lubricants professional service providers, trust them to clean the compressor oil and oil change.

After countermeasures 6: add oil, add new oil weight 0.5% SL anti-wear repair agent, which not only can prolong the service life of bearing, and because the SL contain antioxidant, anti-wear repair agent can make double air compressor oil life.

conclusion

1, the compressor oil catch in it somewhere on the market a lot, it is difficult to find cost-effective products, make up for the solution is to study more to understand more, watch out, 3 without oil and large "dirty oil" problem and a lot of hidden trouble;

2, the life of the compressor oil mainly depends on base oil and additives, different formulations of compressor oil life difference is very big, manufacturers and compressor users should carefully choose;

3, compressor oil, real life is associated with the model, configuration and operating conditions of the compressor;

4, the compressor oil relationship between real life and oil change method is very big, good oil change method measures can make double real life;

5, grasp the overall compressor oil change technology, careful operation, can make the life of the compressor oil real relative lie about 5 times;

6, injection screw air compressor oil real life subject to design scientific, reasonable, effective simulation bench test method, need to the test, after analysis, accurate judgement.