When making PP string wound filter elements, the special roving with fluff is cross-wound on the porous skeleton, and wound to the required specified diameter layer by layer. The roving is continuously cross-wound on the skeleton to form a filter layer containing thousands of diamond-shaped holes. The smaller the diamond-shaped holes on the filter layer near the skeleton on the filter element, the more outward, the larger the diamond-shaped holes, the larger the diamond-shaped holes in the outer layer, and the inside and outside of the diamond-shaped holes pass through to form a channel.
In order to increase the process of the liquid in the filter element, the channels of the diamond-shaped holes are curved and scattered, but the diamond-shaped holes of each layer are still connected. The bending prolongs the diamond-shaped hole channel, which is equivalent to increasing the thickness of the filter layer of the filter element and improving the filtering effect. This is the depth filtration of the filter element. The yarn is wound in a certain parameter, and the inside of the filter element forms a diamond-shaped curved filter channel from the surface to the inside and from large to small.
The size of the rhombus hole in the filter element is the key to determine the accuracy of the filter element. The smaller the diamond-shaped hole, the higher the precision of the filter element; the larger the diamond-shaped hole, the lower the precision of the filter element. Formal filter element manufacturers have a specific comparison table of filter element precision and the number of diamond-shaped holes. Different channel numbers represent different filter element precision. Typically, 8-channel accuracy is 100 μm, 15-channel accuracy is 20 μm, and 19-channel accuracy is 10 μm.
Winding filter element filtration can have a large flow rate through the filter element, but through the structure of dispersing the flow rate, the filter element can still maintain its excellent filtration performance under a small pressure difference. The filter element of this structural form is also conducive to filtering colloid or gel substances in the liquid. PP string wound filter elements can use larger filter holes to filter out particles much smaller than the pore size, so they are often called precision filter elements.
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