乡镇工业砖瓦厂适用通用除尘技术研究

为了控制乡镇砖瓦厂排放粉尘对室内外空气的污染，在改进工艺的基础上，于各产尘点设置了密闭吸尘罩，有效地控制了粉尘向周围环境扩散。根据破碎、筛分等工序排放的含尘空气及粉尘特性，采用了冲击水浴除尘器除尘，针对风选粉碎机等工序排放的含尘空气及粉尘特性，采用了冲击－喷雾联合除尘器除尘。采用上述有效控制技术后，车间工作地点粉尘浓度由原来的每立方米数百毫克降到卫生标准２ｍｇ／ｍ＾３以下，两套通风除尘系统排放粉尘     

水泥厂立窑烟气适宜除尘方法研究

目的 提出小水泥厂立窑烟气应选用的适宜除尘方法。方法 根据ＧＢ／Ｔ１６１５７－１９９６固定污染源排气中颗粒物的测定和气态污染物的采样方法,并使用ＷＹ－１型烟道用７级冲击式尘粒分级仪等测定了立窑烟气的温度、露点温度、粉尘浓度、粉尘粒径分级组成等特性;测定了沉降室、旋风、冲击水浴、冲击－喷雾除尘器的粒径分级除尘效率等特性。结果 在上述基础上,将除尘器与尘源进行合理匹配,提出了排放达标的几种除尘器选型组     

玉石雕刻作业粉尘控制的适宜技术

目的 提供玉石雕刻行业适宜的防尘技术措施。方法 车间粉尘浓度的测定按照GB／T5748－85、通风除尘系统的测定按照GB／T16157－1996的规定进行，使用WY－1型7级冲击式尘粉分级仪测定排气中粉尘的粒径分级组成和除尘器的粒径分级除尘效率。结果 采用了湿式作业，设置了适用的局部通风除尘系统：设计了专门的条缝型吸尘罩，其侧上吸罩罩口风速为2.5m/s、风量为600m^3/h；根据吸尘罩的数量及各风管的风量选定各支、干风管及总风管的直径；选择了冲击式水浴除尘器或滤袋除尘器，对玉石雕刻通风系统排出的含尘空气进行了除尘净化，除尘器的总除尘效率，前者可达97.0%，后者可达98.0%；根据通风除尘系统所需的风量、克服该系统最大阻力管线所需全压及除尘器的阻力确定了风机的机型和参数。结论 实践结果表明，所提供的玉石雕刻作业粉尘控制的适宜技术，可使作业地点粉尘浓度降低到国家卫生标准或接近卫生标准的要求；通风除尘系统排出的含尘空气可以满足排放标准的要求。     

乡镇水泥厂综合防尘适宜技术的研究

目的 研究乡镇水泥厂的适宜防尘技术,以控制尘肺病的发生。方法 采用现场和实验室相结合的综合调研方法。用示踪气体测量抽气罩的效率。按照国家标准（GB／T16157－1996）测定通风管道中的粉尘浓度。采用WY－1型冲击式尘粉分级仪测量各尘源排放粉尘的粉尘粒径分级组成和除尘器的粒径分级除尘效率。结果 （1）工程技术措施方面：提出了破碎、球磨、烘干、烧窑、物料运输和包装等工艺工序的适宜吸尘罩设计（及通用图集）,可有效地控制这些尘源的粉尘外溢。测定不同工序排放烟气的特性（烟气的温度、含水量、粉尘浓度、粉尘粒径分级组成等）,研究了多种除尘器的粒径分级除尘效率、阻力等,提出了各主要工序最适宜方案：破碎、磨机工序除尘以旋风加滤袋或静电等;烘干窑除尘以旋风加静电或冲击喷雾等;立窑除尘以沉降室加静电等;包装工序除尘以滤袋或静电等。（2）组织措施方面：完善职业卫生管理系统,包括建立组织机构、加强职业卫生服务、开展技术培训和职业卫生教育。强调“有效地控制各尘源处的粉尘,防止其向周围扩散”是防止尘肺病发生的最有效方法。结论 提出了乡镇水泥厂适宜综合防尘技术措施,可有效控制水泥尘危害。     

冲击式水浴除尘器在中小工厂的使用

介绍了使用WY-1型尘粒分级仪对冲击式水浴除尘器的粒径分级效率的测定结果;用它所测得的陶瓷、建材行业主要工序排出含尘尾气中粉尘的粒径分级组成;在此基础上,测定了冲击式水浴除尘器使用于上述行业工厂主要工序的效果和预期的除尘效果。     

建材釉砖厂适宜的通风除尘措施研究

目的 探讨釉砖厂适用的通风除尘系统设计方案.方法 选择试点厂,为产尘工序设计、安装通风除尘系统并测定其控尘效果.按照GB 5748-85和GB/T16157-1996测定了工作场所和通风管道中粉尘浓度,使用WY-1型尘粒分级仪测定粉尘的粒径分级组成和除尘器的粒径分级除尘效率,并进行论证.结果 (1)轮碾、斗式提升机、筛分别设置了密闭吸尘罩,轮碾机罩罩口风速为2.5 m/s,斗式提升机、滚筒筛罩的抽风量为1800m3/(h·m2);冲模、质检吸尘罩罩口风速为5和1m/s;(2)上述工序无吸尘罩时粉尘浓度为29.5.255-3 mg/m3,设置吸尘罩后为0.7～1.8 mg/m3;(3)对通风系统排出的含尘空气采用冲击式水浴除尘器净化,除尘后尾气含尘浓度为56.5 mg/m3,除尘效率为97.6%,阻力为800 Pa.结论 釉砖厂安装通风除尘系统后,工作场所粉尘浓度由严重超标降低到1.8 mg/m3;通风系统尾气含尘浓度为56.5mg/m3达到排放标准.     

冲击-喷雾联合除尘器的研究与应用

目的　研究适合排放气体中粒径较细粉尘的除尘器。方法　选择排放粉尘粒径 (<5μm占85 5% )较细的乡镇瓦厂原料旋风分离器尾气排放口 ,研究设计了“冲击 -喷雾联合除尘器”。结果　经测定评价 ,总除尘效率 97 3 % ,排出气体的粉尘浓度 16 0～ 14 1 8mg/m3 。结论　解决了粒径较细、粉尘浓度高、不适用于干式除尘器的粉尘净化问题 ,泥浆废水用于生产不产生二次污染 ,拓宽了水浴除尘器的适用范围 ,展示了利用分级除尘效率选择设计除尘器的方法及意义     

中小工厂防尘中适用除尘器的选型

目的探讨依据不同生产工序粉尘粒度分级组成和除尘器粒度分级效率测定结果进行适用除尘器选型的可行性。方法使用WY-1型冲击式尘粒分级仪测定粉尘的粒径分级组成和除尘器的粒径分级除尘效率。结果（1）①大理石和玉石雕刻、陶瓷、建材、耐火、砖瓦、石粉厂的轮碾、筛分，②陶瓷修坯，③玻璃配料工序的粉尘〉5岬的分别为90．4％～74％、66％、46％；（2）旋风、冲击水浴、冲击喷雾、滤袋、高压静电除尘器对粒径为5μm粉尘的分级除尘效率分别为73．0％、92．1％-98．4％、99．2％、〉99．0％、〉99．0％；计算得出上述除尘器对不同工序总除尘效率。根据有效、适用、经济要求，进行了不同粉尘作业适用除尘器的选型。结论根据现场调查测定结果可进行不同粉尘作业工序适用除尘器的选型，此为防尘设计提供依据。     

郑州北车辆段制动梁电焊除尘系统效果评价

郑州北车辆段日均加修电焊制动梁１５０根，９个电焊作业点同时操作，车间空气中粉尘浓度１３．５ｍｇ／ｍ３。为了治理电焊烟尘，１９９６年初安装了一套通风除尘，并配合工艺改造，使车间粉尘浓度降至２．４ｍｇ／ｍ３。低于国家标准（６ｍｇ／ｍ３）。提示制动梁电焊作业可采用环行流水线降低劳动强度，与工艺配套的通风除尘系统可以有效地控制电焊烟尘，保护职工身体健康。     

石刻雕塑作业粉尘的适宜控制技术

目的 为改善工人的工作环境,控制粉尘的危害,预防工人患上肺病,提供石刻雕塑行业适宜的防尘技术措施。方法 通过对石刻雕塑业的调查研究,现场实测,在总结经验的基础上,本着适用、有效、经济的原则,针对综合防尘技术提供较为详细的设计资料。结果 提供的通风除尘设计方案,可使工作地点粉尘浓度降低到卫生标准或接近卫生标准的要求,通风系统的含尘空气经冲击水浴除尘器或滤袋除尘器除尘后,可以满足排放标准的要求。结论 石刻雕塑行业的通风除尘设计方案,经建筑艺术雕塑厂应用,可以控制作业中的粉尘危害,保护了工人的身体健康。设计方案有科学依据,适用可行,可供基层单位使用。     

吸尘罩的优选及其在玉石雕刻防尘中的应用

目的对适用吸尘罩进行优选,并在实际通风除尘系统中应用。方法用示踪气体法对吸尘罩进行优选,比较不同吸尘罩捕集效率和风量的关系;对吸尘罩前风速分布进行测定,得出罩前风速分布模型。并对吸尘罩进行空气动力性能分析,测定雕刻排气中粉尘的粒径分级组成和除尘器的粉尘粒径分级除尘效率,评估除尘器的总除尘效率。结果优选出的雕刻吸尘罩,置于切割轮正前方0.11 m处,其控制风速为0.5 m/s,能有效地控制雕刻切割轮的粉尘不向周围扩散,工作地点空气粉尘浓度由无罩时的30-297 mg/m3降低至1.1-1.7 mg/m3,吸尘罩风量为255 m3/h,为其他类型吸尘罩的50%-77%。优选出的冲击水浴除尘器,其除尘效率为97%-98%,阻力为1.5 kPa;滤袋除尘器的效率为98%-99%,阻力为2.5 kPa;除尘后尾气的粉尘浓度为20-30 mg/m3。结论提出了优选吸尘罩的设计方法及实用的除尘器,可供实际应用。     

小型喷砂机柜式水幕排风罩矽尘防控有效性研究

目的探究柜式水幕排风罩应用于小型喷砂机防治矽尘的效果,提出粉尘通风防护设施新思路,有效保护劳动者职业健康。方法于2018年8至10月,选取某研究所喷砂间喷砂工艺配置的柜式水幕排风罩为研究对象,采用职业卫生调查、现场检测和气流组织物理相似模拟的方法,对其改造前后的局部排风设施设置情况、矽尘浓度、控制风速、气流组织进行现场检测和发烟测试,并结合设置情况进行分析与评估。结果气流组织模拟实验发现,改造后柜式水幕排风罩气流组织合理,能有效控制工件清扫过程矽尘逸散的全部范围。改造后,控制风速由改造前的0.01 m/s提高至0.53 m/s,控制风速提高98.1%;喷砂、开舱取件及清扫时接触矽尘(总尘)时间加权平均容许浓度(CTWA)由改造前的7.00 mg/m3降至0.50 mg/m3,矽尘(呼尘)CTWA由改造前的3.36 mg/m3降至0.27 mg/m3,其总粉尘和呼吸性粉尘CTWA降尘率分别为92.9%和92.0%。结论柜式排风罩与水幕除尘的一体化结合,优化了粉尘防治的组合方式,具有除尘净化效率高、节能环保等优点,可在同性质企业推广使用。     

清洗消毒对集中空调通风系统空气质量改善效果的评价

目的评价公共场所集中空调通风系统消洗消毒效果。方法依据《公共场所集中空调通风系统卫生学评价规范》(2006年)对天津市46家公共场所102组集中空调通风系统清洗消毒前后相关卫生指标进行监测和评价。结果清洗消毒前后比较,管道积尘量中位数由41.8g/m2降至0.4g/m2,合格率由17.3%(13/60)提高到100%(62/62);积尘中细菌总数和真菌总数中位数分别由14、10cfu/cm2降至1和0cfu/cm2,合格率分别由92.4%(171/185)、82.2%(152/185)提高到99.4%(165/166)、100%(166/166);送风中细菌总数、真菌总数分别由756、382cfu/m3下降为229、120cfu/m3,合格率分别由33.3%(81/243)、62.1%(151/243)提高到79.8%(292/366)、87.7%(242/276)。可吸入颗粒物(PM10)浓度由0.060mg/m3上升至0.068mg/m3,合格率由74.2%(13/60)提高到90.2%(46/51)。结论公共场所集中空调通风系统清洗消毒对改善其送风和管道卫生状况有明显的效果,使用集中空调的公共场所及公共建筑均应定期清洗消毒以保证集中空调的卫生安全。     

Respirable crystalline silica dust exposure during concrete finishing (grinding) using hand-held grinders in the construction industry

Studies reporting the findings of exposure to crystalline silica dust during concrete finishing in construction settings are scarce due to the dynamic nature of the activity and the existence of many confounding factors. This study was initiated to explore the issue. A total of 49 personal respirable dust samples were collected during concrete finishing while workers used hand-held grinders. Only 15 (31%) of the grinders were equipped with local exhaust ventilation (LEV) systems. The confounding factors (e.g. wind velocity, wind direction, relative humidity and ambient temperature) were determined. To make the sampling task-specific, air sampling was activated only during actual grinding. Task-specific sampling times during each work shift ranged from 10 to 200 min. The concentration of total respirable particulate ranged from 0.34 to 81 mg/m3, with a mean +/- SD of 18.6 +/- 20.4 mg/m3, and the concentration of crystalline silica in the samples ranged from 0.02 to 7.1 mg/m3, with a mean +/- SD of 1.16 +/- 1.36 mg/m3. LEV on the grinders reduced the silica dust level significantly (P < 0.01) compared to grinders without LEV. Increased wind velocity also reduced the silica dust concentration significantly (P < 0.03). Working upwind reduced the exposure to silica dust compared to working downwind, but the difference was not statistically significant. The time-weighted average concentration of silica dust in 69% of the samples exceeded the current recommended threshold limit value of 0.05 mg/m3, indicating a strong need to devise methods for controlling workers' exposure to crystalline silica dust during concrete finishing activities.     

Using water sprays to improve performance of a flooded-bed dust scrubber

Supplemental water sprays were placed along the sides of a continuous mining machine to improve suppression and confinement of the dust cloud under the cutting boom to reduce downwind dust levels. Using a full-scale mock-up of a continuous mining machine, preliminary work showed that these side sprays improved suppression of the dust cloud and redistributed this cloud under the cutting head. This led to reductions in dust levels around the machine and in down-wind airways for some positions of the mining machine. This testing also showed that side spray effectiveness was influenced by the distance from the fresh air ventilation device to the cutting surface, termed the ventilation setback distance. These sprays produced larger reductions in machine and return dust levels at smaller setback distances than at larger setback distances. These side sprays then were installed in similar locations on a mining machine at an underground coal mine operation to evaluate their effectiveness for improving suppression and capture of dust by the flooded-bed dust scrubber. Although sampling could not be conducted successfully in the return, sampling around the mining machine and at the machine operator showed that dust levels decreased with use of these sprays. Further analysis showed that these sprays were most effective at the smaller setback distances, a result confirmed by full-scale laboratory testing.     

Crystalline silica dust and respirable particulate matter during indoor concrete grinding - wet grinding and ventilated grinding compared with uncontrolled conventional grinding

The effectiveness of wet grinding (wet dust reduction method) and ventilated grinding (local exhaust ventilation method, LEV) in reducing the levels of respirable crystalline silica dust (quartz) and respirable suspended particulate matter (RSP) were compared with that of uncontrolled (no dust reduction method) conventional grinding. A field laboratory was set up to simulate concrete surface grinding using hand-held angle grinders in an enclosed workplace. A total of 34 personal samples (16 pairs side-by-side and 2 singles) and 5 background air samples were collected during 18 concrete grinding sessions ranging from 15-93 min. General ventilation had no statistically significant effect on operator's exposure to dust. Overall, the arithmetic mean concentrations of respirable crystalline silica dust and RSP in personal air samples during: (i) five sessions of uncontrolled conventional grinding were respectively 61.7 and 611 mg/m(3) (ii) seven sessions of wet grinding were 0.896 and 11.9 mg/m(3) and (iii) six sessions of LEV grinding were 0.155 and 1.99 mg/m(3). Uncontrolled conventional grinding generated relatively high levels of respirable silica dust and proportionally high levels of RSP. Wet grinding was effective in reducing the geometric mean concentrations of respirable silica dust 98.2% and RSP 97.6%. LEV grinding was even more effective and reduced the geometric mean concentrations of respirable silica dust 99.7% and RSP 99.6%. Nevertheless, the average level of respirable silica dust (i) during wet grinding was 0.959 mg/m(3) (38 times the American Conference of Governmental Industrial Hygienists [ACGIH] threshold limit value [TLV] of 0.025 mg/m(3)) and (ii) during LEV grinding was 0.155 mg/m(3) (6 times the ACGIH TLV). Further studies are needed to examine the effectiveness of a greater variety of models, types, and sizes of grinders on different types of cement in different positions and also to test the simulated field lab experimentation in the field.     

Determination of exposure to respirable quartz in the stone crushing units at Azendarian-West of Iran

The purpose of this study is to describe the personal exposure to respirable dust and quartz and in stone crushing units located at west of Iran. A size of 40 personal samples and 40 stationary samples were obtained and analysis was done by X-ray diffraction (XRD). The results of personal sampling were shown the concentrations of respirable dust exposure level in workers of process, hopper and drivers were 1.90, 2.22, 1.41 times greater than Occupational Safety and Health Administration permissible exposure limit (OSHA PEL). The average value of total dust and respirable dust emission from stationary sources was 9.46 mg/m(3), 1.24 mg/m(3) respectively, showing that 13.8 % of total dust is respirable. The efficiency of local exhaust ventilation (LEV) to control of particles inside of industrial units was greater than 99%. It is concluded from this research the particulate generated from stone crushing activities contain a significant amount of respirable particle. The amount of free silica in stone quartz is 85 to 97 percent that emission of particles effect to health workers. LEV has important effect in the removal of silica particles in stone crushing units. The worker of hoppers still exposed to silica more than standard limits.