Lubricating oil is figuratively referred to as the blood of industrial equipment operation. In the process of long-term operation of the equipment, due to the oxidation of lubricating oil, the consumption of additives and external pollution, it may lead to equipment failure and cause significant economic losses. Adopting an oil purification solution that maximizes contaminant capture and reduces maintenance downtime is important to improve equipment performance, extend equipment life, and reduce operating costs. Common oil contaminants are moisture, solid particulates, gases, and lubricant oxides. There are a number of different purification methods for these contaminants:Pressurized mechanical filtration, magnetic filtration, centrifugal separation, sedimentation separation, balanced charge, electrostatic oil filtration adsorption, vacuum dehydration (air), resin absorption and adsorption water removal, coalescence water removalWait. At present, the control technology adopted by various enterprises for oil pollutants such as solid particulate matter and oil oxides is more common in pressurized filtration, balanced charge, electrostatic adsorption and other methods, pressurized filtration is the most traditional and widely used oil purification method, and the use of electrostatic adsorption principle to purify oil is the latest technology developed by modern scientific and technological progress, at present, electrostatic oil filter has been widely used in developed countries and major industrial and mining enterprises in China. Its advantages are more and more affirmed by the majority of equipment workers in the practical application process.
The working principle and advantages and disadvantages of pressurized filtration, balanced charge oil purifier and electrostatic oil purifier
1.1 Traditional Pressurized Mechanical FiltrationTraditional pressurized mechanical filtration has a long history of use, and the user has rich experience. The filtration device has the advantages of high filtration accuracy, easy to use, and high degree of automation; However, the service life of the filter element is relatively short, and the filter element needs to be replaced frequently during work, and it may cause pollution when the work is not careful. In addition, the cartridge filter device cannot effectively remove liquid products such as water and sludge in the oil and particles smaller than the pore size of the filter screen.
1.2 Balanced Charge Oil Purifier Balanced Charge Oil Purifier is to let the oil go in two ways, place positive and negative electrodes in the two ways, load positive ( ) charge one way, load ( ) charge one way, load ( ) charge one way, the pollutants in the oil will be loaded with positive and negative charges after passing through, and the pollutants with positive and negative charges will be mixed again and attracted to each other by the particles of positive and negative charges, and the particles of positive and negative charges will be attracted to each other and condensed and grown, and the size of these tiny particles that are not easy to be intercepted by the filter element will be easily captured and intercepted by the pressure filter after they grow up (see Figure 1). The equilibrium charge part only realizes the condensation and growth of tiny particles, and cannot directly remove particulate pollutants by itself, and the real work of capturing particulate pollutants is completed by the high-precision filter installed after charging and mixing. From the principle, it can be seen that the balance charge oil purifier is exactly the same as the pressurized mechanical filtration except for the charging and mixed flow, but because the charged particles attract each other and become larger in size after cohesion, the fine particles are also removed. The advantage of the balanced oil purifier is that the filtration accuracy is higher, which can reach 01 micron, however, it is less effective than electrostatic oil filters for micro-sized contaminants.
1.3 Electrostatic Oil PurifierThe principle of electrostatic oil purifier is electrophoresis and dielectrophoresis phenomenon. Electrophoresis is the phenomenon in which charged particles are attracted to a surface with opposite polar charges, which is easy to understand and will not be elaborated on. Particles that are already charged in the oil are attracted to the surface with an opposite polar charge and are removed. Dielectrophoresis, on the other hand, is much more complex, involving fluid and particle properties including the dielectric constant of particles and fluids (e.g., lubricating oil), the size of the particles, and the gradient of the electric field domain (which indicates the non-uniformity of the electric field intensity). By dielectrophoretic force, neutral uncharged particulate contaminants can also be attracted to the side of the strong electric field. The electrostatic oil filter uses an electrostatic generator to generate high voltage, and the pleated paper filter element design results in a non-uniform electric field strength with a large gradient of electric field. The strength of the ordinary dielectrophoretic force is determined by the extent to which the non-uniform electric field can polarize the charge distribution of the particles. The uniform electric field passes symmetrically through the particles, and the charge distribution does not change, so there is little or no dielectrophoretic force. However, in the inhomogeneous electric field, the closer you are to the sharp top, the stronger the electric field, and the farther away you are, the weaker the electric field. Regardless of whether the particles are polarized by themselves (lubricating oil oxides) or polarized by a non-uniform electric field (metal wear particles are the most typical), they will move towards a stronger electric field (sharp end). Particles that are not charged and cannot be significantly polarized (non-polar or weakly polar contaminants) are not affected or removed. Finally, the polar solid pollutant particles, highly polar suspended lubricating oil oxides and trace moisture in the oil move to the tip of the pleated filter element under the action of the electric field gradient, and are adsorbed to the surface of the paper filter to be removed. Strictly speaking, the electrostatic oil purifier is not filtering lubricating oil, but the highly polar insoluble liquid lubricating oil oxidation products and charged solid particles in the adsorption lubricating oil, which belong to adsorption rather than filtration. The accuracy of the electrostatic oil purifier to purify the oil is very high, up to 0It is about 10 times more accurate than the balanced charge oil purifier, and can remove oxides such as suspended sludge and trace water (less than 500ppm) in the oil, and prolong the service life of the lubricating oil by removing the suspended lubricating oil oxides. Its high-capacity cartridge has a long service life (2 kg dirt holding capacity) and is suitable for the purification of a wide range of oils. However, because of the adsorption principle, there are certain requirements for the flow rate of the oil, and at the same time, the water content in the oil must be controlled.
Comparison of Pressurized Oil Filter, Balanced Charge Oil Purifier and Electrostatic Oil Purifier
Electrostatic oil purifier and balanced charge oil purifier have high filtration accuracy, can remove sub-micron particle pollutants, at the same time, part of the charge particles that have not had time to adsorb or have not had time to grow up in the group back to the system operation, can have a peeling and adsorption effect on the oil sludge paint film inside the system, including the components on the sludge paint film, long-term operation can play a role in cleaning the entire system.
Technical advantages brought by selective adsorption of electrostatic oil purifiers
The pleated filter design of the electrostatic oil filter creates a strong electric field gradient in the oil stream, so the application of both electrophoresis and dielectrophoresis for selective adsorption brings the following technical advantages.
1) Adsorption of uncharged, but conductive submicron metal particles. The electrostatic oil filter can not only adsorb conventional charged particles through the principle of electrophoresis, but also adsorb neutral particles without charge but with certain conductivity by dielectric power. See 13 parts, therefore, the electrostatic oil purifier has a particularly excellent effect on the removal of metal wear particles, especially submicron non-ferromagnetic metal wear particles, such as copper, tin and other submicron wear particles, pressure filtration and magnetic adsorption are difficult to remove.
2) Adsorption and removal of liquid lubricating oil oxides in a strongly polar suspension state. The electrostatic oil purifier adopts the principle of selective adsorption, because the lubricating oil oxide is a strong polar substance, as long as it is not in a dissolved state but in a suspended state, even the fluid can be adsorbed to the surface of the filter paper on the side of the strong electric field.
3) Remove submicron particles. Based on the principle of selective adsorption, it can effectively remove more than 001 m of solid or liquid suspended contaminants.
4) Retain lubricant additives. Lubricating oil is a fluid composed of base oil and additives, and many users are worried that electrostatic oil purifiers may cause the loss of additives. The adsorption principle of electrostatic oil filter is electrophoresis plus dielectric electrophoresis to remove conductive or strongly polar substances insoluble in oil, which has the characteristics of selective adsorption, and cannot filter oil-soluble substances or non-polar and weakly polar substances insoluble in oil. Base oil itself is extremely polar and can be regarded as a non-polar substance, while additives are conventionally designed to be non-polar or very weak polar in order to dissolve in the base oil, so the electrostatic oil purifier will not remove the additives of the lubricating oil in principle. Even if a small amount of additives are precipitated and suspended in the oil, it is difficult to be filtered out by the electrostatic oil purifier because the polarity of the additives is much weaker than that of metal wear particles or lubricating oil oxidation products. On the contrary, due to the limitation of the principle, the pressurized oil filter has the risk of high-precision filter element filtering out oil-insoluble additives.
Weishengda environmental protection electrostatic oil purifier
It has been proved by the practice of many customers that the Weishengda environmental protection electrostatic oil purifier will not have an adverse effect on the additives during use, on the contrary, the removal of paint film and oxide is conducive to the protection of additives, and at the same time, it has the advantages of high filtration accuracy, large dirt-holding capacity, thorough removal of sub-micron solid suspended liquid pollutants in the oil, and low power consumption; In particular, the paint film generated by the centrifugal compression lubricating oil system, hydraulic oil system and steam turbine lubricating oil system can play a particularly significant peeling effect, and can prevent and solve the temperature fluctuations of bearings and bearings caused by the paint film.