The filter is often classified as a hydraulic accessory. It seems that without it, the cylinder, pump and valve can still work, but the working reliability of a system, and the failure period of the cylinder, pump and valve mostly depends on the working medium (oil, oil, etc.). The advantages and disadvantages of water glycol, emulsion, etc.). To judge the quality of the filter element, the following aspects are mainly considered: the selection of the filter material; the structure of the filter element; the production process; the inspection of the finished product; the appearance quality, etc. Filter material: There are many kinds of filter materials, such as metal mesh, metal felt, glass fiber, plant fiber, organic chemical fiber and so on. The metal mesh is woven from metal filaments, divided into square mesh and twill mesh. It has low flow resistance and can be used in a very high temperature range. Mainly used for coarse filtration of the system, it belongs to surface filtration and can be used repeatedly for cleaning. 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 flow resistance. It has 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, and it is less affected by changes in the working environment. strong ability. Plant fiber is the earliest used fiber filter material. Due to its uneven pore size distribution, it cannot be expressed with absolute accuracy. Only nominal accuracy is used to express the filtration accuracy. The filtration efficiency is low, but due to its lower cost, the temperature range is wider than that of glass fiber. , So it is widely used in engine lubrication, diesel oil, gasoline filtration and air filtration. Generally, the nominal accuracy range is 10~100um. The thickness of the fiber affects the accuracy and oil-passing ability of the filter material. Filter element structure: high-strength, no pollution, no burr, no chemical reaction inner skeleton; inner and outer support nets should have sufficient strength, no pollution, no burr, no chemical reaction; inner and outer lining paper should have high passing ability, high resistance For tensile strength, long-fiber, non-shedding, non-chemically reactive materials should be used. The high-performance filter material should be made of inert fiber and high-strength resin, with uniform pore size, more micropores per unit area, and reasonable and optimal thickness; advanced longitudinal seam bonding, no leakage at the bonding point. Reasonable selection of the sealing form to ensure no leakage at the connection with the filter body; external reinforcement should make the filter material components close to the inner skeleton to enhance impact resistance. Production process and equipment The production environment, production process and production equipment determine the basic conditions for the production of high-quality filter elements. In the production of the filter element, the lap joint of the longitudinal seam and the bonding of the upper and lower covers are a very important part. Appearance quality: refers to the appearance impression of the filter element after it is made, mainly including: whether the processing finish and surface treatment of the upper and lower covers are beautiful; whether the filter material is evenly corrugated and whether it is perpendicular to the upper and lower covers; Whether the viscose is appropriate, uniform, bubble-free and beautiful; in short, to judge the quality of the filter element, it is not only the appearance, but also the inner quality of the filter element, which is more important.
