Oil particle size is an objective measure of the particle size in petroleum products. It reflects the distribution, size and quantity of particles in the oil. There are standards to follow: NAS1638, ISO4406, GJB420, GJB380. 1. The concept of particle size. The particle size refers to the number and concentration of solid particles with different particle sizes in the unit volume of oil, with the unit of pieces/100 ml. It is measured with a special particle size meter. Particle size is an important standard to judge whether turbine lubricating oil is qualified. It is generally believed that when people can't see the oil without particles, that is, the oil is not polluted. In fact, it is less than 40 μ Particles below m are invisible to the naked eye, and are more than 40 μ M Smaller particles have disastrous effects on hydraulic components or bearings, and often these small particles play a key role in the wear process.
2. Reasons for unqualified particle size in turbine lubricating oil. 1) Contaminants left by lubricating oil system components during manufacturing, assembly and overhaul. Such as hair, iron filings, welding slag, dust, etc. These pollutants were not cleaned timely and thoroughly during unit installation and flushing. 2) The oil enters the oil system and pollutes the oil quality. 3) The manual valve at the outlet of the exhaust fan of the main oil tank of the steam turbine is opened too large, and small particles enter each bearing box through the oil baffle, thus polluting the lubricating oil. 4) Normal wear of components of lubricating oil system, hydraulic pumps, bearings and oil supply system pollutes oil quality. 5) The main oil tank is refueled without oil mixing test before normal refueling. The new oil does not match the old oil, producing sludge and polluting the oil quality. 6) The new steam turbine oil is unqualified when entering the plant, and is added into the main oil tank to pollute the lubricating oil in the main oil tank.
3. What is the acceptable standard of turbine lubricating oil particle size? The standard for the quality of steam turbine oil in China is the NAS1638 standard of the American Aerospace Industry Association, which requires that the oil quality must reach Grade 8. Therefore, when the particle size of lubricating oil is greater than 8, it is considered as unqualified. 4. How to deal with unqualified particle size of turbine lubricating oil? 1) When the particle size of the turbine lubricating oil increases, the oil purification device should be started immediately to filter the lubricating oil at any time, and the oil quality should be regularly sampled for testing, and the particle change should be continuously monitored. 2) Investigate the cause of unqualified particle size immediately. Generally, unqualified particle size in operation is due to oil quality pollution. Carry out targeted treatment according to the causes of troubleshooting, and eliminate the cause of oil pollution from the source. 3) If it is suspected that the oil cooler is leaking, switch the oil cooler, put the standby oil cooler into operation, and switch the operating oil cooler; 4) During this period, the oil filter should be operated continuously for 24 hours. In addition to the online oil purification device, the plate oil filter should also be put into operation to filter the oil and control the change of particle size.
