Selection method of filter element

Filters are often classified as hydraulic accessories. It seems that without it, cylinders, pumps, and valves can still work, but the working reliability of a system, the majority of the failure period of cylinders, pumps, and valves depends on the working medium (oil, The pros and cons of water glycol, emulsion, etc.). To judge the quality of the filter element, it is mainly considered from the following aspects: the selection of the filter material; the structure of the filter element; the production process; the inspection of the finished product; the appearance quality. Filter material: Filter materials include metal mesh, metal felt, glass fiber, plant fiber, organic chemical fiber, etc. The metal mesh is woven by metal filaments, divided into square mesh and twill fine mesh. It has low circulation resistance and can be used in a very high temperature range. It is mainly used for the coarse filtration of the system. It belongs to the surface filtration and can be cleaned and used repeatedly. Metal felt is a felt made of metal fiber, which has the properties of glass fiber and belongs to depth filtration. It has a labyrinth three-dimensional structure, high porosity, and low circulation resistance. Strong dirt holding capacity, long service life, and can be used in a wide temperature range. Glass fiber is one of the most common and best-performing filter materials. It is widely used in hydraulic systems. It belongs to depth filtration. The accuracy range is 1~30um. It is less affected by changes in the working environment, and has low flow resistance and pollution. strong ability. Plant fiber is the first fiber filter material used. Because of its uneven pore size distribution, it cannot be expressed with absolute accuracy. Only the nominal accuracy is used to express the filtration accuracy. The filtration efficiency is lower. However, due to the lower cost, the temperature range is wider than that of glass fiber. , So it is widely used in engine lubrication, diesel, gasoline filtration and air filtration. Generally, the nominal accuracy range is 10~100um. The thickness of the fiber affects the accuracy of the filter material and the ability to pass oil. Filter element structure: high-strength, pollution-free, burr-free, and chemical-reaction-free inner framework; inner and outer supporting nets should have sufficient strength, no pollution, no burrs, and no chemical reaction; inner and outer lining paper should have high passing capacity and high resistance For tensile strength, materials with long fibers, no shedding, and no chemical reaction should be used. The high-performance filter material should be made of inert fiber and high-strength resin, the pore size should be uniform, the number of micropores per unit area should be large, and the thickness should be reasonable and most suitable; advanced longitudinal seam bonding, no leakage at the joint. Reasonably choose the sealing form to ensure that there is no leakage at the connection with the filter; the external reinforcement should make the filter component close to the inner frame to enhance the impact resistance. Production process and equipment Production environment, production process and production equipment determine the basic conditions for producing high-quality filter elements. In the production of the filter element, the longitudinal seam overlap and the upper and lower cover bonding are a very important link. Appearance quality: refers to the impression of the appearance of the filter element after it is made, mainly including: whether the upper and lower cover processing finish and surface treatment are beautiful; whether the filter material is uniformly corrugated and whether it is perpendicular to the upper and lower cover; the upper and lower cover and the filter material, the longitudinal seam Whether the viscose is appropriate, uniform, bubble-free and beautiful; in short, to judge the quality of the filter element, it is necessary to look at the appearance and the inner quality of the filter element, and the latter is more important.