气力输送系统旋风分离器的计算方法

目前,在设计制材—木材加工企业的车间气力输送系统时,选择旋风分离器的方法,存在一些严重缺点。 第一,没有根据旋风分离器的几何参数与状态参数来计算除尘量和气动阻力的可靠的经验公式;第二,没有规定评价旋风分离器工作的生态和经济标准的计算方法;第三,完全没有根据各种机床的数量来考虑粉尘微粒质量和尺寸的统计分布;第四,没解决根据已知的总耗气量选择旋风分离器的最佳数目的问题;第五,未研究进入实际车间旋风分离器的混合气流中的粉尘初含量的计算方法。总之,由于上述缺点,将无法达到除尘的卫生标准和最低的能量消耗。 列宁格勒林科院对УЦ型旋风分离器经过几年实验研究,确定了根据旋风分离器的     

旋风除尘器工作原理

粮食工业的初步除尘和风力输送中的卸料器常常用到旋风分离器,该分离器又叫沙克龙分离器,该设备用在除尘上就是旋风除尘器。旋风除尘器是利用含尘气流作旋转运动产生的离心力,将尘粒从气体中分离并捕集下来的装置。旋风除尘器与其他除尘器相比,具有结构简单、没有运动部件、造价便宜、除尘效率较高、维护管理方便以及适用面宽的特点,对于收集5~10μm以上的尘粒,其除尘效率可达90%左右,它广泛应用于粮食、化工、炉窑、烟气等除尘和工厂通风除尘,也用于工业气力输送系统气固两相分离与物料风力烘干物料回收等。此外,旋风除尘器亦可以作为高浓度除尘系统的预除尘器,能与其他类型高效除尘器串联使用。旋风除尘器在粮食行业得到了广泛的应用,如原料输送、加工、包装等生产环节的除尘。     

双压力门闭风装置闭风性能的研究

主要论述了双压力门闲风装置的原理、结构及其特点，并通过调节双压力门处的静压力来研究其排料情况，以及改变旋风分离器的进口风速、进口含尘浓度来考察双压力门的闭风效果，并且使用集灰斗接料(完全密封)和单级压力门闲风与之对比。研究结果表明，双压力门闭风器是一种很好的闲风装置，使用它闭风时的除尘效率与使用集灰斗完全密封时的除尘效率差别很小。它的效率要远远高于单级压力门。     

统收棉杂质收集新方法评估

三次试验旨在对统收棉轧花杂质收集方法——预分离器和旋风除尘器几种组合进行评估。预分离器效率随着预分离器内部的临界速度的减少而增加。除尘效率为90 %的预分离器装置可减少 2 D2 D旋风除尘器粉尘排放物的约 9% ,但对 1 D3D旋风除尘器没有给予这种改进 ,在其中的 2次试验中 ,预分离器实际上导致 1 D3D旋风除尘器排放物的增加。这种反相效应是因为旋风除尘器锥体靠近杂质出口部分的棉绒再循环问题 ,预分离器使这个问题恶化 ,对 1 D3D旋风除尘器更是如此     

对湍球塔用于元明粉干燥尾气除尘的探讨

笔者针对元明粉干燥工序中旋风分离器出口尾气的特性，提出在湍球塔中以水洗除尘的设想，并通过一系列的计算和论证，确定了湍球塔的结构尺寸和相应尾气除尘工艺流程。     

除尘滤袋用PPS纤维毡滤料PM_(2.5)及高温过滤特性研究

除尘滤袋用聚苯硫醚(PPS)纤维毡滤料是高温烟气过滤的重要材料,本研究采用单位面积质量、厚度、透气性、孔径的参数对除尘滤袋用聚苯硫醚(PPS)纤维毡滤料进行表征,考察高温对其动态滤尘性能的影响,探索性的对该类滤料进行PM_(2.5)过滤性能测试,结果表明:在动态滤尘测试过程中,聚苯硫醚(PPS)纤维毡滤料清灰周期、总测试时间随着试验温度的升高迅速下降,而试验温度对除尘效率影响不大;结合测试用粉尘粒径分析和PM_(2.5)旋风分离器,获得滤料的PM_(2.5)过滤效率略低于其除尘效率,这与穿透滤料的粉尘中细颗粒物含量较高的预期相符,结果可靠。     

除尘预分离器清除系统回路分析

本文根据风量平衡和风压平衡定律，分析了预分离器清除系统回路的风量、压力损失和风机风压及其与除尘系统的关系。这些结论为预分离器清除系统的设计提供了理论依据。     

送料风机叶轮的改造

我公司由于生产需要新建了一套芦苇加工处理系统,使用切苇机将芦苇切成长度均匀的苇片,经过双锥除尘器后由除尘风机送至旋风分离器除尘,由旋风分离器出来的苇片储存至一定的数量再由送料风机送至下道工序使用.     

中密度纤维板施胶纤维旋风分离器的适用改造

通过对MDF施胶纤维气力输送旋风分离器结构的改进，针对MDF施胶纤维的特点提出一种适用的旋风分离器结构，并探讨其结构原理和实用计算方法。     

中密度纤维板施胶纤维旋风分离器的适用改造

通过对ＭＤＦ施胶纤维气力输送旋风分离器结构的改进，针对ＭＤＦ施胶纤维的特点提出一种适用的旋风分离器结构，并探讨其结构原理和实用计算方法。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.