Classification of liquid filter bags
Liquid filter bags are divided according to material
Polypropylene fiber (PP, PP) : Polypropylene has good wear resistance and high elastic recovery rate. It is an excellent thermoplastic fiber. Polypropylene felt is often used in low-temperature pulse filter bags in smelting plants and pulse filter bags in chemical and pharmaceutical factories.
Polypropylene precision range: 0.1–500 microns, maximum temperature 94 degrees.
Polyester fiber (polyester, PE) : special polyester fiber has good performance at room temperature, is the main filter material in the bag filter. Can withstand 130℃ operating temperature under dry conditions; Working continuously above 130℃ will harden; Fade; Brittle, and the temperature will weaken it. Accuracy range: 1–300 microns.
Nylon mesh (NMO) : Nylon mesh, also known as nylon mesh, nylon mesh, nylon mesh, is made of nylon 6 (PA6) monofilaments by flexible rapier loom plain weaving, dyeing (if needed), heat set processing. It is made of synthetic fiber and belongs to polyamide system. Nylon wire mesh has high strength, wear resistance, chemical resistance, water resistance and elasticity are better, because the wire diameter is uniform, smooth surface, so the ink through is also very good. The disadvantage is that the tensile property of nylon mesh is larger. This screen in the stretch after a period of time, the tension is reduced, so that the screen printing plate relaxation, precision reduction. Therefore, it is not suitable for printing circuit boards with high dimensional accuracy requirements.
PTFE (polytetrafluoroethylene) : Polytetrafluoroethylene is a kind of neutral polymer compound with unique molecular structure, that is, the structure is completely symmetric. The special structure makes it have good thermal stability, chemical stability, insulation, lubricity, water resistance and so on. High temperature resistance, the use of a wide temperature range, can be 260℃(high temperature for a long time continuous use, instantaneous temperature up to 280℃; Strong chemical stability, corrosion resistance; Good self-lubrication, very low friction coefficient, filtration wear is very small; The surface tension of PTFE film is very low, and it has good inviscosity and water repellency.
PTFE coated filter material can achieve surface filtration, this is because PTFE coated filter material is microporous structure, no straight through the surface of the hole, so that the dust can not pass through the surface of the membrane into the inner membrane or substrate, so that only gas through the dust or material interception on the surface of the membrane. At present, coated filter material has been widely used in industrial dust removal, precision filtration and many other fields.
Glass fiber: deep filter, filter material is composed of multiple layers of glass fiber, suitable for filtering hydraulic oil, lubricating oil, refractory liquid, fuel and synthetic liquid.
Stainless steel mesh: Surface filtered, with very low flow resistance. Filter materials using weaving methods: interwoven, twill and flax type. Metal mesh filter material is suitable for oil absorption filter in hydraulic and lubricating system, or for coarse filtration of high speed fluid, or for safe filtration of coolant.
According to the filtration efficiency of the liquid filter bag is divided into
Relative filtering: Deep filter is on the surface of filter layer and internal to intercept filter, non-woven (also called nonwoven fabric) not woven fiber interwoven irregularly, large particles were intercepted in the outside of the non-woven fabric, first into smaller, but to a certain depth and intercepted, further more smaller impurities, Finally, particles smaller than a certain size and a small number of particles larger than this size are passed. Usually used for deep filtration of polypropylene, polyester, NOMEX, PTFE and other materials of the filter bag, non-woven fabric and other filter consumables internal organization structure, material thickness, fiber surface will affect the interception efficiency of deep filtration. Usually, this kind of filtration is also called relative filtration, and the filtration accuracy is often defined in terms of the filtration efficiency of the impurities of a certain pore size. Different companies have different test methods for filter bag accuracy and filtration efficiency requirements, some defined as 80~85%, some defined as 50~70%.
Absolute filtration: Absolute filtration is a filtration method using surface interception. 95-99.9% of particles larger than a certain size are intercepted, and all particles smaller than this size pass through. The pore size of the filter bag material surface must be consistent, the fiber braid must be tight and firm, the material joint requirements can withstand large pressure, in order to prevent leakage, strictly ensure the absolute filtering effect.