Lee Eun Gyung, Lee Larry, Möhlmann Carsten, Flemmer Michael M, Kashon Michael, Harper Martin
National Institute for Occupational Safety and Health, Health Effects Laboratory Division, Exposure Assessment Branch, 1095 Willowdale Road, Morgantown, WV 26505, USA;
Ann Occup Hyg. 2014 Jan;58(1):60-73. doi: 10.1093/annhyg/met047. Epub 2013 Sep 24.
Pulsations generated by personal sampling pumps modulate the airflow through the sampling trains, thereby varying sampling efficiencies, and possibly invalidating collection or monitoring. The purpose of this study was to characterize pulsations generated by personal sampling pumps relative to a nominal flow rate at the inlet of different respirable cyclones. Experiments were conducted using a factorial combination of 13 widely used sampling pumps (11 medium and 2 high volumetric flow rate pumps having a diaphragm mechanism) and 7 cyclones [10-mm nylon also known as Dorr-Oliver (DO), Higgins-Dewell (HD), GS-1, GS-3, Aluminum, GK2.69, and FSP-10]. A hot-wire anemometer probe cemented to the inlet of each cyclone type was used to obtain pulsation readings. The three medium flow rate pump models showing the highest, a midrange, and the lowest pulsations and two high flow rate pump models for each cyclone type were tested with dust-loaded filters (0.05, 0.21, and 1.25mg) to determine the effects of filter loading on pulsations. The effects of different tubing materials and lengths on pulsations were also investigated. The fundamental frequency range was 22-110 Hz and the magnitude of pulsation as a proportion of the mean flow rate ranged from 4.4 to 73.1%. Most pump/cyclone combinations generated pulse magnitudes ≥10% (48 out of 59 combinations), while pulse shapes varied considerably. Pulsation magnitudes were not considerably different for the clean and dust-loaded filters for the DO, HD, and Aluminum cyclones, but no consistent pattern was observed for the other cyclone types. Tubing material had less effect on pulsations than tubing length; when the tubing length was 183cm, pronounced damping was observed for a pump with high pulsation (>60%) for all tested tubing materials except for the Tygon Inert tubing. The findings in this study prompted a further study to determine the possibility of shifts in cyclone sampling efficiency due to sampling pump pulsations, and those results are reported subsequently.
个人采样泵产生的脉动会调节通过采样系统的气流，从而改变采样效率，并可能使采集或监测无效。本研究的目的是表征个人采样泵相对于不同可吸入旋风分离器入口处标称流速所产生的脉动。实验采用13种广泛使用的采样泵（11种中等流量和2种高体积流量的隔膜式泵）和7种旋风分离器[10毫米尼龙，也称为多尔 - 奥利弗（DO）、希金斯 - 德韦尔（HD）、GS - 1、GS - 3、铝制、GK2.69和FSP - 10]的析因组合进行。将热线风速仪探头固定在每种旋风分离器类型的入口处，以获取脉动读数。针对每种旋风分离器类型，测试了显示最高、中等和最低脉动的三种中等流量泵型号以及两种高流量泵型号，使用加载粉尘的过滤器（0.05、0.21和1.25毫克）来确定过滤器负载对脉动的影响。还研究了不同管材和长度对脉动的影响。基频范围为22 - 110赫兹，脉动幅度占平均流速的比例范围为4.4%至73.1%。大多数泵/旋风分离器组合产生的脉冲幅度≥10%（59种组合中的48种），而脉冲形状差异很大。对于DO、HD和铝制旋风分离器，清洁和加载粉尘的过滤器的脉动幅度没有显著差异，但其他旋风分离器类型未观察到一致的模式。管材对脉动的影响小于管材长度；当管材长度为183厘米时，除了泰贡惰性管材外，对于高脉动（>60%）的泵，在所有测试的管材材料中都观察到了明显的阻尼。本研究的结果促使进一步研究以确定由于采样泵脉动导致旋风分离器采样效率变化的可能性，后续将报告这些结果。
