Selection of special oil for circulating lubricati

2022-08-03
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Selection of special oil for circulating lubrication system of papermaking machinery equipment (Part 2)

1.3 special oil for circulating system

for the working conditions of high speed, heavy load, high temperature of paper machine trunk and contact between wet end and water of papermaking equipment, special lubricating oil PMO (paper machine oil) for circulating system shall be selected

1.3.1 PMO features,

(1) good viscosity temperature property to ensure normal lubrication in case of large change of working temperature

(2) good oxidation stability to ensure that the deterioration speed of oil products is slowed down during recycling and the service life of oil products is prolonged

(3) good anti rust property to ensure good anti rust effect on lubricated parts

(4) the good anti foaming property makes the bubbles generated during the oil circulation more and more favored by the users, and gradually replaces the steel wire rope sling in many aspects, which is easy to disappear, so as to ensure the normal oil supply and the formation of oil film

(5) good demulsibility, so that the water mixed in the oil can be separated quickly to ensure the service performance of the oil

(6) good filtration performance to prevent blockage of the filtration system

(7) good extreme pressure and anti-wear performance to avoid wear and abrasion under heavy load

(8) good detergency and dispersion to prevent carbon deposition

1.3.2 viscosity brand and performance index of PMO

pmo150, pmo220 and pmo320 can be provided by Great Wall lubricating oil company in China. The viscosity grades of PMO are 150, 220 and 320, and its main performance indexes are shown in the table below

Table 3 main performance indexes of special oil (PMO) for paper machine circulating system

iso viscosity grade 150, 220, 320 experimental method

40 ℃ kinematic viscosity, m each gear needs calibration m2/s gb/t265

viscosity index, ≮ 95 gb/t2541

flash point (opening) ℃, ≮ 235 gb/t 267

pour point ℃, ≯ -6 gb/t 3535

copper corrosion, 121 ℃, 3h, ≯ 1b gb/t 5096

demulsibility () min/82 ℃ ≯ 20 gb/t 7305

liquid phase corrosion test (distilled water) rust free gb/t 11143

rotating oxygen bomb test 150 ℃, min, ≮ 300 sh/t193

timken OK value, IBF, ≮ 50 gb/t11144

1.3.3 application of PMO

(1) selection principle of viscosity

selected oil products if the viscosity is too large, the internal friction resistance will increase, the power loss will also increase, the friction heat will increase, and the deterioration of the oil will be accelerated, After a certain temperature is exceeded, fatigue is accelerated; If the viscosity is too small, the lubricating oil film is thin and the strength is not enough, which increases friction and wear, and even produces non fluid lubrication or dry friction, thus damaging the machinery. Generally, low viscosity oil shall be selected at high speed and low load; Select high viscosity oil at heavy load and low speed

(2) oil performance monitoring

during the use of oil products, they gradually deteriorate due to the effects of heat oxidation, mechanical shear, and the mixing of wear powder, moisture, dust, etc., resulting in the increase of viscosity, acid value and water content, the generation of oil sludge, and the darkening of color. They must be monitored regularly and replaced in time as required. Usually the test items include viscosity, acid value, mechanical impurities and moisture. Replacement indicators are as follows:

Table 4 oil replacement indicators (for reference only)

test method for oil change indicators of the project

viscosity change rate ± 15% gb/t265

acid value increased by 1.0mgkoh/g gb/t4945

moisture 0.5% gb/t 260

mechanical impurities 0.5% gb/t 511

copper corrosion, 121 ℃, 3h, Equal to or greater than 3b gb/t 5096

2. differences between special oil for paper machine circulating system and other oil products

according to the oil consumption survey conducted by the author during his visit to the paper mill, many paper mills did not use special oil for paper machine circulating system in three ways of digital LCD display and computer control display, but used other oil products instead, resulting in poor lubrication and wear of equipment lubricating parts, The circulating lubrication system is blocked due to oil sludge

the circulating lubrication system of papermaking machinery must use special oil, and cannot be replaced by other oil. For example, the commonly used mechanical oil only has the function of anti-oxidation and anti rust, and its level is general, which can not meet the requirements of the circulating lubrication system of paper machinery for oil oxidation stability, extreme pressure and anti-wear, anti emulsification performance, filtration performance, etc

gear oil cannot be used to replace the special oil for paper machine circulation system. The circulating lubrication system of paper machine may contact with water under working conditions, so the demulsification performance of oil is more strict. In addition, as it is a circulating lubrication system, it has stricter requirements on the filtering performance of oil products. It takes more than 15 (4) 5 days to have a longer service life. Therefore, it has higher requirements on oxidation stability. Since some parts to be lubricated by the circulating lubrication system are made of copper, the requirement for copper corrosion is higher than that of gear oil

do not replace gear oil with hydraulic oil. Because the circulating lubrication system not only lubricates the bearings, but also lubricates the gears, the extreme pressure performance requirements are more stringent than that of hydraulic oil

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