توصيفگر ها :
فيلتر , الياف استبرق , لايه بي بافت , نفوذپذيري , تخلخل , قطر منافذ , ملت بلون , دستگاه ارزيابي راندمان
چكيده فارسي :
هدف از اين پژوهش، بررسي خصوصيات نفوذپذيري و راندمان فيلترهاي بي‌بافت تهيه شده از الياف استبرق مي‌باشد. استبرق از جمله الياف طبيعي سلولز‌ي تو‌خالي با چگالي پايين است كه به طور وسيع در ايران رشد مي‌كند و براق و سوزني شكل هستند . در اين پژوهش در ابتدا دو نوع الياف استبرق، يكي با يك سال عمر از زمان برداشت و ديگري با دو سال عمر پس از زمان برداشت از نظر خصوصيات فيزيكي و شيميايي با هم مقايسه شدند تا تاثير زمان بر روي خصوصيات آن‌ها بررسي گردد. يكي از متغيرهاي مستقل در اين پژوهش، تعداد لايه‌هاي بي‌بافت استبرق روي هم قرار داده شده ( در هفت سطح) مي‌باشد كه همزمان با افزايش تعداد لايه‌‌ها، خصوصياتي از قبيل وزن، ضخامت، نفوذپذيري، تخلخل و قطر منافذ لايه اندازه‌گيري شد. سپس براي افزايش راندمان فيلتر متشكل از لايه‌هاي بي‌بافت استبرق از لايه ملت‌بلون استفاده شد كه وجود يا عدم وجود لايه ملت‌بلون و محل استقرار آن در لايه‌هاي بي‌بافت استبرق يكي ديگر از متغيرهاي مستقل در اين تحقيق مي‌باشد. در اين پژوهش به منظور اندازه‌گيري راندمان، يك دستگاه كوچك در مقياس آزمايشگاهي طراحي و ساخته شد. اساس كار دستگاه، اندازه‌گيري وزن ذرات به دام افتاده و ذرات منعكس شده از بستر فيلتر بود. از ذرات سيمان براي تست راندمان استفاده شد زيرا هدف از توليد اين فيلتر، استفاده در كارخانه سيمان مي‌باشد. در نهايت پس از تعيين فيلتر بهينه از آزمايش‌هاي مذكور، راندمان آن مطابق با استاندارد EN-779 توسط دستگاه مجهز به شمارنده ذرات موجود درآزمايشگاه فيلتراسيون شهرك علمي و تحقيقاتي اصفهان براي ذرات دي‌اتيل‌هگزيل‌سبكات (DEHS) در ابعاد مختلف مشخص گرديدكه براي بزرگترين ذرات DEHS (5/2 ميكرون)، 5/74 درصد تعيين شد، همچنين راندمان اين فيلتر براي ذرات سيمان حدود 94 درصد به دست آمد، بر اين مبنا مشخص شد كه دستگاه طراحي شده به صورت قابل قبول مي‌تواند براي مقايسه راندمان فيلتر‌ها مورد استفاده قرار بگيرد.
چكيده انگليسي :
Today, airborne particles and pollution are one of the most dangerous problems that human beings face in the fields of health and society. Many of these pollutants enter the environment by factories and industrial units and cause many respiratory and incurable.The use of filter substrates is one of the most common methods of control. Textiles are among the most important filter substrates. Despite the fact that woven textiles have many uses in dry and wet filtration, non-woven textiles have gained more attention due to their cheapness, availability of raw materials, flexibility and ease of production, as well as high efficiency. The purpose of this study is to investigate the permeability properties and efficiency of nonwoven filters made of estabragh fibers. estabragh is one of the natural low-density hollow cellulose fibers that grows widely in Iran and is shiny and needle-shaped. These fibers, despite having unique properties and the possibility of cultivation in the country, have not been much attention in the textile industry.This can indicate the importance of this research in order to produce non-woven layers of these fibers with filtration properties. In this study, two types of estabragh fiber were first compared, one with one year of harvest time and the other with two years of harvest time in terms of physical and chemical properties To investigate the effect of time on their characteristics. Due to the lack of surface waveform on the estabragh fibers and low interaction between the fibers, web production the carding machine was impossible. In order to achieve stable carding operations of spin fibers, the required amount of spinning oil was sprayed on the fibers and also the humidity of the spinning hall was increased up to 70%. Finally, a number of non-woven layers of estabragh fiber were produced by a laboratory card machine. One of the independent variables in this study is the number of estabragh non-woven layers stacked on top of each other (in seven levels). As the number of layers increased, characteristics such as weight, thickness, permeability, porosity and pore diameter were measured and the results the face was obtained. By increasing the number of layers from one to seven layers, the permeability decreased by 86.82% and the porosity by 1.52%. Also, the average pore size was reduced by 24.78% using the relation provided by Chapman. The properties of the three-layer non-woven estabragh were then predicted using the corresponding diagrams and equations. Then, to increase the efficiency of the filter consisting of estabragh non-woven layers, the meltblown layer was used. The presence or absence of meltblown and its location in estabragh non-woven layers is another independent variable in this study, Once again, two meltblown layers were placed on the top and bottom of the estabragh layer and its properties were measured. In this study, a small device on a laboratory scale was designed and built to measure efficiency. The basis of the device was to measure the weight of trapped particles and particles reflected from the media filter. Cement particles were used to test the efficiency because the purpose of producing this filter is to use it in a cement factory. Finally, after determining the optimal media from the mentioned experiments, its efficiency was determined according to EN-779 standard by a device equipped with a particle counter in the filtration laboratory of Isfahan Scientific and Research Town for Diethylhexylsebacat (DEHS) particles in different dimensions. That for the largest diethylhexylsebacat particles (2.5 microns), 74.5% was determined, and the efficiency of this media for cement particles was about 94%. Based on this, it was found that a device designed to be acceptable could be used to compare media efficiencies.
