Precision filter, also known as security filter, is generally set in front of the pressure vessel to remove fine particles with turbidity more than 1 degree, so as to meet the requirements of the subsequent process for water inflow; Sometimes it is also set at the end of the whole water treatment system to prevent fine particles (such as broken resin) from entering the finished water.

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Precision filtration devices (also known as security filters) are mostly made of stainless steel with filter elements (such as PP cotton) inside. They are mainly used after multi-media pretreatment filtration and before membrane filtration equipment such as reverse osmosis and ultrafiltration. It is used to filter the fine substances (such as tiny quartz sand, activated carbon particles, etc.) after multi-media filtration, so as to ensure the filtration accuracy of water quality and protect the membrane filtration elements from the damage of large particles. The precision grade of filter element in precision filter device can be divided into 0.5 μ s,1 μ s,5 μ s,10 μ According to different use occasions, different filtration precision is selected to ensure the effluent precision and the safety of membrane elements.

PPC, nylon, meltblown and other materials are used as filter elements to remove micro suspended solids, bacteria and other impurities in the water, so that the raw water quality can meet the requirements of reverse osmosis membrane.

Process principle

Security filter belongs to precision filter, its working principle is to use PP filter element 5 μ Mechanical filtration was carried out in the pores of 0. The residual micro suspended particles, colloids and microorganisms in the water are trapped or adsorbed on the surface and pores of the filter element. With the increase of water making time, the operation resistance of the filter element increases gradually due to the pollution of intercepts. When the water pressure difference between the inlet and outlet reaches 0.1MPa, the filter element should be replaced. The main advantages of security filter are high efficiency, small resistance and easy replacement.

Structure and principle

The security filter adopts the shaped filter material. Under the action of pressure, the original liquid passes through the filter material, the filter residue remains on the pipe wall, and the filtrate flows out through the filter material, so as to achieve the purpose of filtration. Structure: filter cloth, filter screen, filter piece, sintered filter tube, wire wound filter element, melt blown filter element, etc. Due to different filter materials, the filtration pore size is also different. Precision filtration is a kind of filtration between sand filtration (coarse filtration) and ultrafiltration. The filtration pore size is generally 0.5 ~ 120 μ M range. The same type of filter material can be divided into different specifications according to the size. There are two kinds of wire wound filter element (also known as honeycomb filter element): one is polypropylene fiber --- polypropylene skeleton filter element, with the maximum service temperature of 60 ℃; The other is degreased cotton fiber - stainless steel framework filter element, the maximum temperature of 120 ℃. Melt blown filter element is a kind of filter material with polypropylene as raw material and melt blown process. The maximum working temperature is 60 ℃. Precision filtration can remove suspended solids, some colloidal substances and small particles in water.

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(1) The water source is generally fixed and cannot be changed easily.

(2) Improve the operation effect of pretreatment, optimize the dosage of flocculant and coagulant aid, select the scale inhibitor suitable for the water source, adjust the pretreatment equipment to achieve the best operation state, strictly follow the requirements of operating procedures, and ensure the quality of pretreatment effluent.

(3) The brand filter element with guaranteed quality can not only prolong the service life of the filter element, but also ensure the effluent quality of the security filter. For example, the filtration accuracy of geosonics filter element is 5 ± zero point five μ m. Geosmonics new Purex filter element with Z. plex technology redefines all previous ro pretreatment performance and filter element construction standards. Z. Plex technology adopts short diameter melt blown filter element, wide layer spacing and a three-dimensional fiber matrix Purex filter element, which is particularly suitable for water treatment applications, because the fine sediment particles in water treatment applications are easy to cause fouling of reverse osmosis equipment. This kind of filter element is incomparable in intercepting water pollutants, with lower pressure loss and longer service life than most similar filter elements. Under the no-load shell of the filter element, the fiber and three-dimensional network form a variety of pores, which can effectively capture impurities. In the next filter layer, the number of small pores in the unique fiber structure of Z. plex technology is increasing until the filter core, which can maximize the filter life and sludge removal efficiency.

For accurate micron filtration, the inner core is the last layer. The inner core is a hot-melt bonded structure with incomparable integrity, cleanliness and rigidity, and no support core is required. Similarly, the adhesive coating with strong permeability is very smooth, which can prevent the loose fiber from moving, which is critical for applications with high purity requirements.

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Features precision filter has the following features:

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It can effectively remove suspended solids and rust in liquid.

. can withstand high filtration pressure.

The unique deep mesh structure enables the filter element to have high slag loading capacity.

The filter element can be made of various materials to meet the needs of various fluid filtration.

Small size, large filtration area, small resistance and long service life

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Function and purpose

In order to prevent the suspended particles that are not completely removed or newly generated in the pretreatment from entering the RO system and protect the high-pressure pump and RO membrane, the filter element type security filter is usually set before the RO water enters. Generally, the aperture is less than 10 μ m. According to the actual design, it can be designed as 5 μ M or less.

component

The security filter is mainly composed of filter shell and filter element. Most of the filter shell is made of r304 stainless steel. If it is used in special occasions such as acid and alkali resistance, r316 stainless steel can be used as the shell. It can be divided into flange type and clamp type, and flange type shell is mainly used in the occasion of large filtration flow. The filter element installed in the middle of the filter shell is mainly PP filter cotton core. In some cases, the wire wound filter element or activated carbon filter element can also be selected. The installation number of filter elements can vary from one to dozens, which is mainly determined according to the size of the treatment capacity.

Common filter element types

The filter materials mainly include sintered filter tube, melt blown fiber filter and honeycomb filter.

The sintering tube is made of powder material by sintering, and its filter tube materials include ceramics, glass sand, plastic, etc. Melt blown fiber filter element is generally made of polypropylene as raw material, which is heated, melted, sprayed, drawn and received. Polypropylene filter element is commonly used as raw material. Honeycomb filter element is made of textile fiber roving which is wound on the porous framework. Polypropylene wire wound honeycomb filter element is commonly used.

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matters needing attention

The inlet and outlet water of security filter shall be provided with pressure gauge. When the inlet and outlet water pressure difference reaches the limit value during operation, the filter element shall be replaced in time. As the cleaning recovery efficiency of the filter element is low, it is best to use disposable filter element.

Installation method

1. Take the package apart and put it in good order

2. Install the filter element

3. Fix the filter element into the filter tank

4. Fix the tank cover and install the vent valve.

technical parameter

Design pressure: 0.75-1.6mpa

Design temperature: 20 ℃ ~ 120 ℃

Sealing type: O-ring and flat gasket

Sealing material: nitrile rubber, silica gel, fluorine rubber and polytetrafluoroethylene, etc. the standard configuration is silica gel sealing

Interface type: jaw, clamp, GB, Hg, DIN, ANSI, JIS standard flange

Applicable filter element: flat and 222 and 226 socket filter elements

Surface treatment: Matt spraying, mirror polishing, electrolytic polishing

Filtration accuracy: 0.5 μ m--100 μ m

Material: SUS304 316L

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Scope of application

1. Nanofiltration (NF), ultrafiltration (UF), reverse osmosis (RO), electrodialysis (EDI) system security filtration and terminal filtration;

2. Medical injections, infusion, eye drops, Chinese herbal medicine, etc. are filtered, and biological preparations are extracted, purified and concentrated;

3. High purity water pre filtration and terminal filtration for electronics, microelectronics and semiconductor industry;

4. Filtration of oilfield reinjection water, boiler make-up water, chemical reagents, liquid organic products, high-purity chemicals, concentrated chemicals, etc;

5. Filter purified water, mineral water, fruit juice, tea drink and health drink;

6, wine Baijiu, wine, beer, yellow wine and other fruit wine filtration, pure draft beer sterilization (instead of pasteurization);

7. Pretreatment filtration or security filtration in the process of production and domestic wastewater treatment and reclaimed water recycling;

8. Others are bioengineering, oil refining, printing and dyeing, water supply and wastewater treatment in textile industry, scientific research and experimental filtration, etc

Applicable industries

The quality of the effluent meets the food hygiene standard. It can be used in hotels, schools, food factories, beverage factories and families to prepare cold drinking water and beverages, and as a pure water preparation unit