How to improve the filtering accuracy of sintered filter element- Ningbo Jiangbei District Cicheng Pneumatic Components Factory.

The filtration accuracy of sintered filter elements is mainly determined by the pore structure of the filter material and its distribution uniformity. In the raw material selection stage, the selection of metal or non-metal powders with narrow particle size distribution is one of the key factors to improve the filtration accuracy. For example, strict screening of powder raw materials by laser particle size analyzer to ensure that the standard deviation of powder particle size is controlled within ±5% can significantly reduce the pore inhomogeneity caused by particle size differences during sintering. At the same time, nano-scale modification of the powder surface, such as the introduction of alumina or silica coating, can enhance the bonding strength between particles and form a denser sintered structure.

Precise control of sintering process parameters is an important part of improving filtration accuracy. The use of vacuum sintering technology can create an oxygen-free environment, effectively avoid oxidation of metal powders, and promote atomic diffusion between particles. Studies have shown that when the sintering temperature is controlled in the range of 80 to 120°C below the melting point of the metal and combined with a vacuum degree of 0.1 to 1Pa, the porosity of the sintered body can be reduced to less than 15%, while maintaining an open porosity of more than 30%. For porous ceramic filter elements, freeze drying is used to pre-treat the slurry, which can form directional pore channels during the sintering process, thereby improving the filtration accuracy by 2 to 3 orders of magnitude.

Structural optimization design provides new possibilities for improving filtration accuracy. By optimizing the flow channel structure of the filter element with the help of computer simulation technology, the uniform distribution of the fluid inside the filter element can be achieved. For example, the tree-like fractal flow channel designed using the bionic principle can reduce the fluid flow velocity gradient by 40%, thereby reducing the local filtration load. In addition, a gradient pore structure is constructed on the surface of the filter element, that is, the outer layer uses a large-pore filter material for pre-filtration, and the inner layer uses an ultra-fine pore filter material for fine filtration. This composite structure can increase the overall filtration efficiency by more than 50%.

Surface treatment technology provides important support for improving the performance of sintered filter elements. Chemical etching technology can form a nano-scale rough structure on the surface of the filter element by precisely controlling the reaction time and temperature, thereby increasing the contact area between the filter material and the fluid. For example, etching a stainless steel filter element with a sulfuric acid-hydrochloric acid mixture can increase its specific surface area by 2 to 3 times, significantly improving its ability to intercept tiny particles. Plasma modification technology introduces polar groups on the surface of the filter element to enhance the adsorption selectivity of the filter material for specific substances. In the application of hemodialysis filter elements, this technology can increase the urea removal rate by 15%.