Comparison of five materials for filtering dust

Due to the decrease in air quality, especially in some northern cities, you cannot go out without a smog mask in winter. The reason why the smog mask has the effect of preventing smog is because of the filtering material inside. There are currently five main types of filter materials.

1. Glass fiber material

The most prominent features of glass fiber are high temperature resistance, good dimensional stability, and high tensile strength at break. In terms of chemical resistance, glass fiber is very stable to other media except hydrofluoric acid and high temperature and strong alkali. The disadvantage of glass fiber is its poor folding resistance, and it is generally not used on oscillation or pulse systems.

2. Polypropylene material

Polypropylene has good abrasion resistance, high elastic recovery rate, acid and alkali resistance, good moisture resistance, and weak oxidation resistance. It is also an excellent thermoplastic fiber. Polypropylene felt is often used in low-temperature pulse filter bags in melting plants and chemical , In the pulse filter bag of a pharmaceutical factory. Polypropylene is specially used in damp places, and it is limited by low temperature resistance.

3. Polyester material

The most common reason for polyester damage is the hydrolysis of water vapor or the increase of water temperature, especially the hydrolysis corrosion in alkaline environment. It can withstand the operating temperature of 130 ℃ under dry conditions; it will become hard when continuously working above 130 ℃; Fading; brittle, temperature will weaken its strength


4. PTFE (polytetrafluoroethylene) fiber and membrane filter material

Features: PTFE is a neutral polymer compound with a unique molecular structure, that is, a completely symmetrical structure. The special structure makes it have good thermal stability, chemical stability, insulation, lubricity, water resistance, etc.

Filtration performance: high temperature resistance, wide operating temperature range, can be used continuously at 260℃ (long-term continuous use at high temperature, the instantaneous temperature can reach 280℃; strong chemical stability, corrosion resistance; good self-lubrication, very low friction coefficient, very low filter wear Small; the surface tension of the PTFE membrane is very low, with good non-stick and water repellency.

The PTFE coated filter material can achieve surface filtration. This is because the PTFE coated filter material has a microporous structure and has no through holes on the surface, so that dust cannot enter the inside of the membrane or the substrate through the surface of the membrane , so that only gas passes through. Keep dust or materials on the surface of the membrane. At present, the coated filter material has been widely used in many fields such as industrial dust removal and precision filtration.

The surface of the polytetrafluoroethylene (PTFE) film is smooth and resistant to chemical substances. It is laminated to the surface of the ordinary filter material to act as a disposable dust layer, trapping all the dust on the surface of the film, and achieving surface filtration; The film has a smooth surface, excellent chemical stability, non-aging, and hydrophobic, so that the dust trapped on the surface is easily peeled off, and at the same time, the service life of the filter material is improved.

Compared with ordinary filter media, its advantages are:

1). The membrane pore size is between 0.23μm, the filtration efficiency can reach more than 99.99%, and almost zero emission is achieved. After cleaning, the porosity is not changed, and the dust removal efficiency is always high.

2). The pressure loss of the membrane filter material at the beginning of use is higher than that of the ordinary filter material, but after it is put into operation, the pressure loss changes little with the increase of the use time, and the pressure loss of the ordinary filter material will change with the use time The lengthening and getting bigger and bigger.

3). Dust can easily enter the inside of ordinary filter media in use, and it accumulates more and more, until the pores are blocked and the use cannot be continued. With the use of PTFE coated filter material, the filtered dust can be easily removed from the surface of the membrane. The dust removal effect is good, the cycle is long, and the cleaning pressure intensity used is low, which improves the service life of the filter material and reduces the operating cost of the product..


5. Antistatic fiber

Stainless steel fiber and carbon or other antistatic elements are mixed with the fiber to help reduce the risk of static electricity accumulation. This kind of antistatic fiber is often used in the occasions where the bag filter has the risk of explosion.

It Generalmente se espera que cuando el material del filtro garantice la misma eficiencia de filtración, cuanto mayor sea la permeabilidad del aire, cuanto menor sea la resistencia, mejor, porque esto puede ahorrar mucha energía. En un colector de polvo que usa flujo de aire para expulsar el polvo, Se utiliza la misma presión y el mismo volumen de aire. Cuando se utiliza el flujo de aire para eliminar el polvo, el efecto de eliminación del polvo cuando se utiliza un material tejido con una gran permeabilidad al aire como bolsa de filtro es mejor que seleccionar un material tejido con una pequeña permeabilidad al aire .Cómo mejorar el material del filtro con la condición de que el material del filtro alcance una mayor precisión de filtración La permeabilidad al aire del medio filtrante, la mejora del acabado de la superficie, la reducción de la adherencia del polvo y la reducción de la resistencia al funcionamiento son los primeros temas que el fabricante del material filtrante debería estudiar.

La velocidad de filtración se calcula mediante la siguiente fórmula:

v = Q / 60 × A

Donde v-velocidad de filtración (velocidad aparente del aire de filtración), m / min

Volumen de aire de procesamiento del colector de polvo Q-filter, m3 / hora

A － Área de filtrado del material filtrante del colector de polvo del filtro, ㎡

La alta tasa de filtración aumentará la diferencia de presión entre los dos lados del material del filtro, exprimirá el polvo fino que se ha adherido al material del filtro y reducirá la eficiencia de filtración para alcanzar el valor de emisión especificado o desgastar la fibra única del filtro. material. Acelere especialmente el daño del material de filtro de fibra de vidrio. Si la velocidad de filtrado es pequeña, el volumen del colector de polvo aumentará, lo que aumentará la inversión. La velocidad de filtración es uno de los principales factores que afectan el rendimiento de los colectores de polvo de filtro.


Los catalizadores de monóxido de carbono, catalizadores de descomposición de ozono, catalizadores de COV, catalizadores de Hopcalita, catalizadores de dióxido de manganeso y catalizadores de óxido de cobre también necesitan usar materiales de filtro en la parte delantera y trasera durante el uso para evitar que salga un poco de polvo en el catalizador.