Company Name: Kunshan Hao Hong lubricants Limited
Contact: Manager Li
Customer Service: 18914053614
Address: Suzhou City, Jiangsu Province, Kunshan City Zhangpu Jinhua West Village plant
Hydraulic oil as a hydraulic transmission system works hydraulic energy transmission medium in the hydraulic system plays an important role in energy transfer, lubrication system, corrosion and rust and cooling, and the cleanliness of hydraulic oil directly affects the performance of the hydraulic system , The life of hydraulic components and so on, so in the construction machinery hydraulic system filter technology is more widely used. Hydraulic oil filtration is a key technology, once the hydraulic oil cleanliness problems will inevitably affect the normal operation of construction machinery and equipment.
Second, hydraulic oil filter technology introduction
Hydraulic oil filtration technology which uses lipophilic hydrophobic technology and the "air pocket" principle, the contact area of the oil in the vacuum separator expanded to hundreds of times the original, and "air pocket" system in turn make the oil evaporation surface area increases , And the evaporating interface is continuously updated, increasing the stroke of the oil in the vacuum system and the static water evaporation area, so that the water in the oil is rapidly vaporized and evaporated under the conditions of low heat, high vacuum, large surface and high pumping speed, System discharge. The water and gas discharged from the upper part of the vacuum separator are cooled down by the cooling system step by step and finally discharged into the air by a vacuum pump. Vacuum separator by vacuum vaporization dehydration after drying oil, the pump from negative pressure to positive pressure, after fine filtration, the net oil discharged from the oil outlet to complete the entire oil process. Hydraulic oil filtration technology is an important technology for system protection in construction machinery Hydraulic oil in the system means that the pressure transmission, lubrication, to seal the role of the cooling If you choose not to be appropriate, it will lead to system failure and pollution So in the choice of hydraulic oil should be in accordance with the appropriate rules and procedures for the correct operation of the hydraulic oil of different materials can not be mixed or will have a huge pollution in use should be in accordance with the rules of regular maintenance Long-term monitoring can play a role in the use of equipment rate.
Third, filtration dehydration principle
Liquid wetting on the solid surface can be divided into wetting, soaking and spreading three, spreading is wet conditions. In other words, if water can spread on a solid surface, it must also be able to wet and soak solids. Wettability is good or bad based on the contact angle (or wetting angle) to measure the size.
The size of the contact angle depends on the nature of the liquid and the solid. Specifically by the role of the three-phase point on the various types of interface surface tension coefficient σ water solid, σ oil solid, σ oil water balance between the decision. ? The oil-water force attempts to minimize the surface of the water droplets to reduce the surface energy between the oil and water. ? The oil-strength map unfolds the droplets to cover the solid surface (trying to absorb the liquid to reduce the surface tension) because the solid surface itself can not shrink, To reduce the surface energy between oil and solid. Σ water solid strength map to reduce the area of water-solid interface to reduce the water-solid interface energy. When the system reaches equilibrium, the water drops form solid contact angles with the solid surface. The smaller Θ, the better wetting performance.
According to the size of the contact angle, the solid material is divided into two categories, a class of solid water is good for its wettability, and oil on its wettability is not good, these types of solid called hydrophilic solid or oleophobic solid (θ <90 °), such as glass, quartz, various types of inorganic salts and metal oxides, etc .; the other type of solid oil is good for its wettability, and water wetting performance is not good, called lipophilic solid or hate An aqueous solid (θ> 90 °), such as solid hydrocarbons, large hydrocarbon weakly polar organic solids, inorganic sulfides and the like. Liquid substances are generally divided into two categories, one is a non-polar liquid (such as hydrocarbon liquid), almost all the good wetting most solids; the other is a polar liquid (such as water), you can only wet well A small number of solids (such as glass, quartz, inorganic salts, etc.). It can be considered that the closer the polarity of the liquid to the solid, the better the wettability.
Oil-water dispersion is a thermodynamically unstable system, and some process measures can be taken to destroy the conditions for maintaining the stable existence of such a dispersion system, so that the tiny water particles in the oil can be aggregated into larger water droplets and the oil-water separation can be achieved by settling. Filtration Dewatering The use of fiber media on the different affinity of oil and water, through the two filter layers: the cohesion layer and the water repellent layer, to achieve the separation of emulsified water filtration.
There are mainly three kinds of interaction between water droplets and coalesced fiber layer: interception (micro-droplets of movement directly contact with fibers), Brownian diffusion and inertial collision. Gravity, electrostatic charge, and van der Waals forces exert an influence on these three interactions. Water droplets are in contact with the fibers under these effects.
Water droplets in contact with the fiber, there is an oil film between them. However, the coalescing fiber layer is a hydrophilic substance. Water droplets displace the oil film from the hydrophilic surface, so water droplets displace the oil film from the fibers and wet the fibers, allowing the water droplets to adhere to the fibers.
The efficiency of water droplets adhering to the fiber depends on the nature of the fiber surface contact angle θ, diameter and the droplet size. And, the smaller the contact angle, the smaller the diameter of the fiber, the greater the water droplet size, the easier it is to adhere to the fiber surface.
According to the principle of reduced free surface energy, water droplets condense in two ways after wetting the fiber:
(1) Water droplets aggregate on the wetted fiber surface. Water droplets continue to adhere to the surface of the fiber, water droplets and water droplets meet each other will converge into a large water droplets;
(2) the condensation of water droplets in the fiber pores. Due to the high density of the fiber layer, the pores between the fibers are small, and the water droplets and the water droplets also meet each other in the fiber pores to condense into large water droplets.
In both cases the contact angle 0 ° ~ 180 ° at the same time. The first case is the main one. When the water droplets reach a certain particle size, the water droplets will desorb or flow along the fiber surface under the force of the oil flow and the gravity of the water droplets themselves, and form a water channel connecting to the lower fiber. After passing through the porous layer, Water droplets will desorb from the surface of the fiber under the same force as the fiber, the fluid dynamics of the fluid, and gravity.
Two-phase liquid flows to the water-repellent layer with the oil flow. The water repellent layer is made of water-repellent material with a contact angle of 180 °. Water on the water-repellent layer due to interfacial surface tension effect, in its capillary water resistance effect, the oil can smoothly through the water-repellent layer, while the water droplets are obstructed. In order to achieve the separation of oil and water.
Water resistance, also known as Jia Min effect: If there is liquid in the capillary diameter larger than the insoluble droplets, and the wetting of the capillary droplet is not good, then the capillary will have a resistance effect. The reason for the water resistance effect can be explained by the surface energy. Spherical water droplets through the capillary, it is necessary to change the shape, from spherical to non-spherical, thereby increasing the water droplets with the oil interfacial area, the surface energy also increases. To increase the surface energy to increase the external pressure to do work (ie surface work), this external pressure that is to overcome Jiamin effect force.
Fourth, concluding remarks
In summary, in the process of construction machinery and equipment used in the hydraulic oil we need timely filtering and maintenance, to ensure the normal operation of machinery and equipment. Continuous use of new technologies and new processes to improve the purity of hydraulic oil, reduce mechanical failure.