压力位差式气体层流流量传感器开发

基于压力位差式气体层流流量技术,进行了新型层流流量传感器的设计和测试工作.传感器由本体和集成盖板两部分组成,壳体采用一体化加工,毛细管组固定于壳体的两个流道中,取压盖板使用内部嵌入式管路联通的方式代替外部取压管,毛细管组、滤网、管路连接件等均采用模块化设计,差压、绝压和温度传感器集成在取压盖板上.分析了传感器工作原理,给出了修正公式,基于活塞式气体流量标准装置进行了空气和氮气两种介质的实验测试,最大流量约为50 L/min.测试结果显示,两种气体的流量测量误差均小于±0.8％,量程比达到250倍.预计这种传感器可以在微小气体流量准确测量领域获得应用.

Development of the pressure potential differential type laminar flow transducer for gas flow measurement

Based on the pressure potential differential (PPD) type gas laminar flow technology, a new type of laminar flow transducer is designed and tested. The flow transducer is composed of two components, i. e. main part and integrated cover plate. The shell of the transducer is machined from a block material, and capillary components are fixed in the two channels of the shell. There are internal embedded channels in the cover plate for pressure acquisition, which can replace outside pressure tubes. Other components, such as capillary components/ bundles, mesh filter, and pipe connector, are designed with the idea of modularity. The differential, absolute pressure sensors, and temperature sensor are integrated on the pressure acquisition cover plate. The principle of the PPD gas flow transducer is analyzed and the correction formula is given. Based on a piston gas flow standard device, the PPD laminar flow transducer was calibrated with air, and tested with air and nitrogen gases. The maximum flow rate is about 50 L/ min. The results show that, the flowrate measurement errors for the two kinds of gas are within ±0. 8%, and the turndown ratio is about 250. It is predicted that the PPD laminar flow transducer will be used in the micro & small gas flow measurement fields.