Discussion on the characteristics and selection of the filter of the magnetic turning column level gauge

There are two main fluid filtration mechanisms. One is separation based on the size of particles, such as interception, screening, and surface capture; the other is adsorption, that is, particles adhere to the filter under chemical/charge action. This requires each pharmaceutical factory to choose different filter membranes according to their actual needs.

    It is related to the characteristics of the fluid. For example, fluid viscosity and chemical/ionic composition, the greater the fluid viscosity, the slower the flow rate under the same pressure conditions, the more contact between the fluid and the membrane, and the better filtering effect; another example is the mixing of fluid and membrane. The contact time also has a greater impact on the filtering effect. The longer the mixing/contact time, the better the filtering effect. In addition, it should be noted that the characteristics of the fluid only affect the adsorption and retention effect of the membrane on the fluid and not the elimination of particle size.

    It is related to actual operating conditions, such as particle flow rate and filtration pressure. To achieve a good filtration effect, generally choose a lower flow rate, the lower the flow rate, the better the retention effect. Practice has proved that the structure movement of the membrane is unfavorable to filtration. Once the structure of the membrane changes during the filtration process, particles and fibers can be precipitated from the depth filter, which will affect the filtration effect. However, the velocity/pressure difference only has an important effect on adsorption retention, and has a relatively small effect on size elimination.

    The particle type is also closely related to the filtering effect. There are two types of particles: deformable particles and non-deformable particles. Under a certain pressure, deformable particles will enter the filter membrane and cause more filter meshes to be blocked, thereby affecting the filtering effect, such as gel filtration. However, when immutable particles are filtered, a cake-like object is formed on the filter membrane.

    Water filters are generally divided into depth filters, surface filters and membrane filters. The fibers of the depth filter sometimes fall off, and an exact pore size cannot be given. The thickness is generally 3-20mm. It usually has adsorption effect and has a large dirt bearing capacity; the fiber of the surface filter is generally thermally bonded or membrane It is coated to give a rated pore size, relatively thin (<1 mm), and small adsorption capacity; the main characteristics of membrane filters are hard texture, not easy to break, tortuous channels and very high internal surface area, and have a certain The open porosity can be used for integrity testing, and is often used for deep filtration, such as sterile filters.

    Water filtration is an indispensable treatment method in the purification process of fluids, mainly used to remove particles or other suspended matter in the fluid. The principle of the filter is to use porous media to remove contaminants from the fluid, so that the fluid reaches the required cleanliness level. A filter is often thought of as a simple mesh or sieve, and filtration or separation is performed on a surface. This is the way in the past, and now most filters have a certain thickness of the filter wall, that is to say, the filter equipment has a depth, in the form of a "curved channel" played an auxiliary role in removing pollutants. The filter is a device to remove a small amount of solid particles in the liquid. When the fluid enters the filter cartridge with a certain specification filter screen, its impurities are blocked, and the clean filtrate is discharged from the filter outlet. When cleaning is needed, the pipe is turned The bottom screw plug, drain the fluid, remove the flange cover, take out the filter cartridge, and reinstall it after treatment. As we all know, the core element of the filter is the filter membrane, which is a membrane filled with smaller pores prepared on a microporous supporting layer. There are many materials for making filter membranes, which are divided into organic membranes and inorganic membranes. Membrane filters have high filtration accuracy, relatively stable particle size control, and easy backwashing to restore performance. Therefore, it is extremely convenient to use and maintain.