The string wound filter cartridge is refined by winding the textile fiber yarn with good filtering performance on the porous skeleton. The yarn materials include polypropylene fiber, acrylic fiber, absorbent cotton fiber and so on. By controlling the tightness and thinness of the yarn during winding, string wound filter cartridges with different precisions can be made. In today's article, we will briefly understand the relevant characteristics of the string wound filter cartridge.
1. Structure characteristics of string wound filter cartridge
When making the string wound filter cartridge, the special roving with fluff is cross-wound on the porous skeleton and wound layer by layer to the required diameter. The roving is continuously cross-wound on the skeleton to form a filter layer with thousands of diamond-shaped holes. The diamond-shaped pores on the filter layer near the frame of the filter element are small, the more outward, the larger the diamond-shaped pores, the outermost diamond-shaped pores are the largest, and the diamond-shaped pores penetrate inside and outside to form a channel. In order to increase the flow of liquid in the filter element, the rhombic hole channel is curved and scattering, but the rhombic holes of each layer are still connected. The bending makes the rhombus hole channel extend, which is equivalent to increasing the thickness of the filter layer of the filter element and improving the filtering effect. This is the filter element. Where the deep filtration is, the yarn is wound with certain parameters, and the inside of the filter element forms a diamond-shaped curved filter channel from the surface to the inside, from large to small). The size of the innermost diamond-shaped hole of the filter element is the key to determining the accuracy of the filter element. The smaller the diamond-shaped hole, the higher the accuracy of the filter element; the larger the diamond-shaped hole, the lower the accuracy of the filter element. Formal filter element manufacturers have specific filter element accuracy and diamond hole number comparison table, and different channel numbers represent different filter element accuracy. Normally, the accuracy of 8 channels is 100μm, the accuracy of 15 channels is 20μm, and the accuracy of 19 channels is 10μm.
2. Filtration characteristics of string wound filter cartridge
Another feature of the string wound filter cartridge is that it can pass a larger flow. Each string wound filter cartridge of filtration accuracy has a fixed number of channels D. After the filtration accuracy is determined, the number of channels L will increase or decrease according to the length of the filter element.
The formula for the total number of channels is: total number of channels = D×L×2.
Take a filter element with a length of 250 mm as an example, its filtration accuracy is 20 μm, the number of channels on its diameter is 15, and the number of channels along the length of the filter element is 51, the total number of channels for the filter element is 15×51× 2 = 1530, that is, there are 1530 independent channels on the filter element. If the filtration flow rate is 0.5m³/h (take clean water as an example), that is, 8.3 L/min, the liquid is dispersed into 1530 independent channels for filtration, and the flow rate in each channel has actually dropped to 5.4 mL/min.
If the filtering precision is 3 μm, the number of channels is 27, and the number of channels is 91, the total number of channels on the filter element is 27 × 91 × 2 = 4 914 (pieces). Therefore, for the 3 μm precision filter element, although the filter medium (ie, fiber fluff) has become denser, the number of filter channels has increased to 4,914, and the flow rate in the channel is only 1.7 mL/min. The flow rate at this time can be called "Siphon Flow".
It can be seen that the string wound filter cartridge can pass through the filter element with a large flow rate during filtration, but the structure of dispersing the flow rate allows the filter element to maintain its excellent filtration performance under a small pressure difference. This structure of the filter element is also beneficial Filter out colloidal or gelatinous substances in the liquid. The string wound filter cartridge can filter out particles much smaller than the pore size with a larger filter hole, so it is often called a precision filter element.