Application of PTFE membrane filter material with induction heating roller

1. Background 

      PTFE composite filter material plays an important role in environmental pollution protection in modern industrial production, mainly internal protection and external protection. The application of internal protection refers to the production of many industrial products with high requirements on production environment, such as electronic products, health products, medical products, etc., which need a certain clean production workshop. Filter materials and multiple methods are used to isolate the clean space and produce products in the clean space in order to achieve the performance of the products in the clean space; External protection refers to that in industrial production, harmful gases, dust and other harmful substances will be discharged into the atmosphere, and the substances harmful to the atmosphere and surrounding environment will be effectively filtered through filtering materials to achieve the purpose of environmental protection, such as dust filtration of cement plants and power plants. In addition, ePTFE membrane is also used in civil clothing fabrics, which plays a role of waterproof and breathable. ePTFE is a kind of microporous membrane formed from polytetrafluoroethylene. It is found that the surface of PTFE membrane is covered with fibrillar micropores, and there are as many as 9 billion micropores in each square inch. Its ross section is a kind of network structure. There are many complicated structures in the three-dimensional structure of the hole, such as mesh connection, hole inlay, hole bending and so on. The diameter of water vapor molecule is 0.0004 μ m, while the diameter of light fog with the smallest diameter in rain water is 20 μ m, the diameter of drizzle has been up to 400 μ m, and the micropore diameter of polytetrafluoroethylene varies from 0.1 to 0.5 μ m, and the pore diameter is between steam and rain water, so it is the top waterproof and breathable material. The composite fabric is made of expanded polytetrafluoroethylene film (ePTFE) and polyester fiber by special process.

 The effect of ePTFE membrane filter material has obvious characteristics

1). Remarkable dust removal efficiency:
    Because of its special structure, PTFE membrane filter material has a dust removal efficiency as high as 99.99%, which greatly exceeds the national standard and is close to zero emission.

2). Wide adaptability of using environment
    Polytetrafluoroethylene (PTFE) membrane filter material has strong adaptability to temperature, humidity and corrosive gas because of its high and low temperature resistance, anti condensation and chemical stability, and non-aging performance. The effect is better especially used for the high concentration, high humidity, fine dust gas use. These performances are incomparable with the conventional filter media at present.

3). Good air permeability:
    The air permeability is an important index to measure the performance of filter materials. The air permeability of PTFE membrane filter material can reach 3 ~ 6m3 / m2 · min, which has exceeded the requirements of practical use.

4). Good economic benefits
    The service life is closely related to the economic benefit (because of the special structure of the membrane filter material, its service life can reach more than 3 years). In three years, the capital needed to use conventional filter bags is much more than the investment in the use of coated filter bags. Moreover, the use of coated filter bags can save a lot of labor and recover more valuable dust. So the economic benefits are conceivable. According to the calculation, the investment can be saved by 25-30%.

2、 Existing technical defects:
    The current production process of ePTFE composite filter material is as follows:Mixing, casting, drying, longitudinal drafting, transverse drafting, compounding, slitting and winding. In the existing technology, the drying process, drafting process and composite process adopted for PTFE film-forming and lamination, and the heating mode of hot roller adopts heat-transfer oil heating or electric heating, which has the problems of temperature uniformity and safety of heat-transfer oil; in the application scenario of high-temperature composite, the heat-transfer oil can not meet its high-temperature heating demand. The roller body is heated by electric heating. The usual way of heat transfer is directly through air radiation. There are problems such as poor temperature stability and control lag, which can not guarantee the normal process.

3. Solution:
    The induction induction heating roller is used to replace the heating roller in the existing drying process, drafting process and composite process. The excellent temperature uniformity and accurate temperature control can provide effective and reliable quality of the composite filter material.

4. Product parameters:
    Roller size: Ф 350 × 780mm (Draft) Ф 500 × 2580mm (composite) Ф 400 × 3000mm (composite)

    (can be customized according to customer requirements)
    Heating power: 20~190kw (customized)
    Working temperature: 100~280 ℃, 280~ 420 ℃
    Linear speed: 5 ~50M / min