Development of spunlaced nonwoven filters from PAN, PPS and PI fibres for industrial use

The aim of this work was to produce filter fabrics suitable for high temperature and other conditions encountered in coal power plants using the spunlacing manufacturing technique. Polyacrylonitrile (PAN), polyphenylene sulfide (PPS) and polyimide (PI) fibres being combined suitable for this purpose, each at three aerial density of (440, 500 and 560 g/m2) and each at three water jet pressures of (60, 80 and 90 bars) were produced. The effect of changing these on the fabric air permeability, tensile strength and filtration properties were investigated and optimized. For this purpose, the Box-Behnken experimental design (BBD) was considered the best and therefore used. The PPS/PI fabrics were found to consistently have the highest air permeability, tensile strength and filtration performance, followed by the PPS fabrics and the PAN fabrics. As could be expected, an increase in area weight and water jet pressure generally resulted in a decrease in air permeability irrespective of the fabric types, this being due to the increased number of fibres and therefore greater fibre surface area and entanglement respectively. For fabric tensile strength, the effects of varying fabric area weight and water jet pressure were not so straight forward. For cross direction (CD) an increase in water jet pressure resulted in an increase tensile strength whereas in the machine direction (MD) there was a decrease when the water jet pressure was increased. The filtration efficiency and dust holding capacity of the fabrics were found to be around 96% and 211g/m2, respectively, with the exception of the PPS (500 g/m2 80 bar) fabrics. Increasing the amount of dust being fed to the fabric during each loading cycle, it caused an increase in pressure drop, as the fabrics became increasingly clogged forming a cake layer

Development of spunlaced nonwoven filters from PAN, PPS and PI fibres for industrial use

The aim of this work was to produce filter fabrics suitable for high temperature and other conditions encountered in coal power plants using the spunlacing manufacturing technique. Polyacrylonitrile (PAN), polyphenylene sulfide (PPS) and polyimide (PI) fibres being combined suitable for this purpose, each at three aerial density of (440, 500 and 560 g/m2) and each at three water jet pressures of (60, 80 and 90 bars) were produced. The effect of changing these on the fabric air permeability, tensile strength and filtration properties were investigated and optimized. For this purpose, the Box-Behnken experimental design (BBD) was considered the best and therefore used. The PPS/PI fabrics were found to consistently have the highest air permeability, tensile strength and filtration performance, followed by the PPS fabrics and the PAN fabrics. As could be expected, an increase in area weight and water jet pressure generally resulted in a decrease in air permeability irrespective of the fabric types, this being due to the increased number of fibres and therefore greater fibre surface area and entanglement respectively. For fabric tensile strength, the effects of varying fabric area weight and water jet pressure were not so straight forward. For cross direction (CD) an increase in water jet pressure resulted in an increase tensile strength whereas in the machine direction (MD) there was a decrease when the water jet pressure was increased. The filtration efficiency and dust holding capacity of the fabrics were found to be around 96% and 211g/m2, respectively, with the exception of the PPS (500 g/m2 80 bar) fabrics. Increasing the amount of dust being fed to the fabric during each loading cycle, it caused an increase in pressure drop, as the fabrics became increasingly clogged forming a cake layer

Filtering function of vertically pleated textile products (ROTIS II)

katedra: KTT; přílohy: 1 CD; rozsah: 89 s.There is a growing use of nonwovens in technical applications such as filtration. The ability to understand the parameters that influence the filter medium is important for the use of filter media. Parameters like pressure drop and efficiency are the two most important parameters that filter media designers consider when designing filter media. The aim of this study is to test if the geometry of pleated filters produced by the ROTIS II technology has influence on the following filtering parameters: pore size, pressure drop and filtration efficiency. This will also involve comparing these parameters to find if there is linear relationship between them. For this study pleated filter media was prepared using the ROTIS II technology and tested. Their results were compared to that of flat filter media to find out if the is an influence on filtering parameters. The permeability coefficient results have shown that pleating the filter media increases its permeability coefficient than flat filter media. However if were to use the same weight of material for flat filter as in pleated filter media we will increase permeability coefficient slightly higher than that of double layered filter media. Pleating the filter media changes the pore sizes. Pores can be smaller or larger than that of flat filter media depending on the pressure. There is no linear relationship between pore size and permeability coefficient. There are varied results for pore size against dust starting pressure as such we could not come to the conclusion that there is linear relationship between pore size against dust starting pressure. Pleating the filter media increases the efficiency of the filter media that do not have 100 percentage efficiency. The pore size influences the efficiency of the filter media. The smaller the pore size the higher is the efficiency and the larger the pore size the smaller is the efficiency however this linear relationship does not apply to filter media that have 100 percentage.There is a growing use of nonwovens in technical applications such as filtration. The ability to understand the parameters that influence the filter medium is important for the use of filter media. Parameters like pressure drop and efficiency are the two most important parameters that filter media designers consider when designing filter media. The aim of this study is to test if the geometry of pleated filters produced by the ROTIS II technology has influence on the following filtering parameters: pore size, pressure drop and filtration efficiency. This will also involve comparing these parameters to find if there is linear relationship between them. For this study pleated filter media was prepared using the ROTIS II technology and tested. Their results were compared to that of flat filter media to find out if the is an influence on filtering parameters. The permeability coefficient results have shown that pleating the filter media increases its permeability coefficient than flat filter media. However if were to use the same weight of material for flat filter as in pleated filter media we will increase permeability coefficient slightly higher than that of double layered filter media. Pleating the filter media changes the pore sizes. Pores can be smaller or larger than that of flat filter media depending on the pressure. There is no linear relationship between pore size and permeability coefficient. There are varied results for pore size against dust starting pressure as such we could not come to the conclusion that there is linear relationship between pore size against dust starting pressure. Pleating the filter media increases the efficiency of the filter media that do not have 100 percentage efficiency. The pore size influences the efficiency of the filter media. The smaller the pore size the higher is the efficiency and the larger the pore size the smaller is the efficiency however this linear relationship does not apply to filter media that have 100 percentage

A review of wound dressings treated with Aloe vera and its application on natural fabrics

Natural wound dressings extracted from Aloe vera leaves have gained greater recognition in the treatment of wounds due to their ability to accelerate wound healing and their nontoxic nature for humans and the environment. Treated wound dressing allows the removal of moisture and movement of gases to and from the wound area while the antimicrobial agent in it suppresses microbial growth. Extracted Aloe vera components can be applied directly into a fabric or they can be electrospun to nanoparticles that are incorporated into the fabric. Because biological antimicrobial agents like Aloe vera are not highly effective against high concentrations of microorganisms, chemical antimicrobial agents are still used even though they are harmful. Processing Aloe vera using methods like the thermal treatment method makes the Aloe vera lose some of its therapeutic benefits. Natural fabrics treated with Aloe vera can be used as an alternative to chemical agents used for wound treatment. Natural wound dressings treated with natural antimicrobial agents have the advantage of preventing microbial growth while at the same time promoting wound healing without activating the immune response as they are biocompatible