The Security Filter is generally installed before the pressure vessel to remove fine particles with a turbidity above 1 degree to meet the requirements for water ingress in the subsequent process. Sometimes it is also set at the end of the entire water treatment system to prevent small particles (such as broken resin) from entering the finished water.
Security filters are mostly made of stainless steel with a filter element (such as PP cotton) inside. They are mainly used after multi-media pretreatment filtration and before reverse osmosis and ultrafiltration membrane filtration equipment. Small substances (such as tiny quartz sand, activated carbon particles, etc.) to ensure the water filtration accuracy and protect the membrane elements from damage by large particles. The accuracy of the filter element in the security filter device can be divided into 0.xn--5s-99b, 1μs, 5μs, 10μs, etc. Different filtration accuracy can be selected according to different use occasions to ensure the accuracy of the water outlet and the membrane element.
The security filter uses PP cotton, nylon, meltblown and other different materials as the filter element to remove tiny suspended solids, bacteria and other impurities in the water, so that the raw water quality can meet the water inlet requirements of the reverse osmosis membrane.
1. Process principle
The working principle of the Security Filter Housing is to use the pores of the filter element for mechanical filtration. The trace suspended particles, colloids, microorganisms, etc. remaining in the water are trapped or adsorbed on the surface and pores of the filter element. As the water production time increases, the operation resistance of the filter element gradually rises due to the pollution of the trapped material. When the operation reaches 0.1 MPa between the inlet and outlet water pressure difference, the filter element should be replaced. The main advantages of the security filter are high efficiency, low resistance and easy replacement.
2. Structure and principle
The Stainless Steel  Security Filter adopts a shaped filter material. Under the action of pressure, the original liquid passes through the filter material, the filter residue is left on the tube wall, and the filtrate flows out through the filter material to achieve the purpose of filtration.
Structure: filter cloth, filter screen, filter disc, sintered filter tube, wire wound filter element, melt blown filter element, etc.
Due to the different filter materials, the filter pore size is also different. Filtration is a kind of filtration between sand filtration (coarse filtration) and ultrafiltration. The filter pore size is generally in the range of 0.5~120μm. The filter material of the same type can be divided into different specifications according to the appearance size.