Design On Gas System Of Personal Sampling Pump

Occupational health standards of China's express unit has been using the maximum allowable concentration (MAC) past, is insufficient to assess the actual exposure level of workers, and with international practice does not converge.In 2002 the new promulgation's standard "Industrial Enterprise Designed Sanitation Standard" as well as in 2007 new revision standard GBZ2.1 "Operational Exposure Limits for Hazardous Agents In the Workplace Chemical Hazardous Agents " and GBZ2.2 " Operational Exposure Limits for Hazardous Agents In the Workplace Physical Agents " proposed that the occupation contact limiting value used time weighted average admissable concentration (TWA) to indicate much.TWA concentration used for detection, we need 8 hours of continuous application of sampler, the use of these machines are imported, which is very expensive, high demand and can not promote,the use of which has now resulted in the standard can not be implemented.The national more than 2000 occupational health monitors and the appraisal organization, besides purchased few imported the TWA sampling instrument, the major part did not have the use corresponding sampling instrument,so that create the maximum error, even was unable the correct sampling determination.This article is to seize the domestic occupational health monitoring of the current difficult problems, conduct research and design of new air sampling individual's gas system, adapt to the individual-based TWA testing the new standards, so an accurate reflection of workers on the dust and toxic the actual exposure level.This article in view of this reality request, has conducted the research to the personal sampling pump gas systems. First of all, through domestic and foreign production and using gas sampler units of research and information retrieval, in accordance with the requirements of the standard to determine the corresponding personal sampling pump gas system technical performance and technical indicators;Next, carry on the investigation and study to the main primary device product situation of sampler gas systems, optimal as well as the examination; Finally, to sampler gas system's constituent: cyclone sampling head as well as the low current capacity adapter carries on the theoretical design.In this paper, the main research results are designed the integration of personal sampling pump gas system ,which can realize the sampling of dust and toxic , in addition to the adoption of experimental and theoretical study of design and calculation, by the following conclusions:(1) A reasonable personal sampling pump gas system should use flow sensor technology to replace rotameter which needs artificial regulation and thus a better solution sampler unsteady flow problems.(2) Cyclone sampling head has the following features: simple structure, no moving parts, high separation efficiency and pressure drop moderate, and the separation characteristics of the sampling head can meet the corresponding requirements. In this paper, through the use of Barth, Leith formula for calculating, in accordance with the requirements of deal volume, the partition size and basic design-related data in conformity with our standard sample curve--BMRC curve required cyclone sampling head.(3) In order to realize the on the integration of dust, toxic personal sampling, this paper designed a low-flow adapter. Through needle valve can change the tee cross-sectional of low-flow adapter, thus changing the sample flow, and thus able to meet the requirements of toxicology sampling norms.