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Distinguish the quality of the filter element

Jan 30, 2020

Filters are often classified as hydraulic accessories. It seems that without them, cylinders, pumps, and valves can still work, but the reliability of a system's work. The failure period of cylinders, pumps, and valves depends on the working medium (oil, water glycol, emulsion, etc.).

Judging the quality of the filter element is mainly considered from the following aspects:

Selection of filter material; structure of filter element; production process; finished product inspection; appearance quality, etc.

1. Filter media

Filter materials include metal mesh, metal felt, glass fiber filter, plant fiber filter, and organic chemical fiber.

The metal mesh is woven from metal filaments, divided into square mesh and twill mesh. It has low circulation resistance and can be used in a high temperature range. It is mainly used for coarse filtration of the system. It belongs to surface filtration and can be repeatedly cleaned and used.

Metal felt is a felt made of metal fiber, which has the properties of glass fiber and belongs to deep filtration. It has a three-dimensional labyrinth structure, high porosity, and low circulation resistance. It has strong dirt holding capacity, long service life, and can be used in a wide temperature range.

Glass fiber filter element is one of the most common and best-performing filter materials. It is widely used in hydraulic systems and belongs to depth filtration. The accuracy range is 1 ~ 30um. Pollution ability is strong.

Plant fiber filter is the earliest used fiber filter material. Due to its uneven pore size distribution, only the nominal accuracy is used to express the filtration accuracy, and the filtration efficiency is low. Lubrication, diesel, gasoline filtration, and air filtration. The general nominal accuracy range is 10 to 100um. The thickness of the fiber affects the accuracy of the filter material and the oil permeability.

2. Filter element structure:

High strength, no pollution, no burr, no chemical reaction of the inner skeleton; the inner and outer support nets should have sufficient strength, no pollution, no burrs, no chemical reaction; the inner and outer liner paper should have high passing capacity and high tensile strength Use long-fiber, non-shedding, non-chemically reactive materials. High-performance filter materials should be made of inert fibers and high-strength resins, with uniform pore diameters, a large number of micropores per unit area, and a reasonable and optimal thickness; advanced longitudinal seam bonding, and no leakage at the joints. Reasonably select the sealing form to ensure that there is no leakage at the connection with the filter body; the external reinforcement should make the filter material components close to the inner frame to enhance the impact resistance.

3. Production process and equipment

The production environment, production technology, and production equipment determine the basic conditions for producing a high-quality filter element. Longitudinal seam overlap and upper and lower cover bonding are a very important link in the production of filter elements.

4. Appearance quality

It refers to the appearance impression after the filter element is made, mainly including:

Whether the finish and surface finish of the upper and lower covers are beautiful; whether the filter material ripples are uniform and vertical to the upper and lower covers; whether the adhesive on the upper and lower covers and the filter material and the longitudinal seams of the filter materials are appropriate, uniform, air-free and beautiful;

In short, judging the quality of the filter element depends on both the appearance and the intrinsic quality of the filter element, and the latter is more important.