摘要
气相色谱分析仪一般采用注射器手动单个进样。这种进样方式不能够大批量进样,进样一个样品一般需要2 min,并且在手动进样过程中不能排除由于工作误差导致的样品与大气存在交换,不仅费时费力,而且无法保证进样量的准确性,会导致检测结果出现偏差。因此,自动进样管理(EPC)系统应运而生,解决了手动进样中不能大量进样和进样偏差导致的结果误差,使检测结果更加准确、可靠。分析仪要求整个气路系统气体纯净并连续运行,且流速要稳定、密闭性好、流量测定准确。精确的气路流量检测和流量控制是实现EPC的前提。主要设计了一种气路流量的检测与控制的电路方案。方案选用PIC32MX6高性能单片机对WBIM200高精度气体流量传感器进行管路流量监控,通过控制气路电磁阀实现气路的关闭以及气路流量的调节,进而达到对气路流量的精准控制和监测。
Gas chromatography analyzers generally adopt a syringe to manually inject a single sample.But this injection method cannot be applied to inject large quantities of samples.In general,it takes about 2 min to inject only one sample.In the manual sample injection process,the exchange between samples and atmosphere caused by working errors cannot be ruled out,which not only takes time and effort,but also cannot guarantee the accuracy of sample injection,thus resulting in the deviation of detection results.Therefore,electric pneumatic control(EPC)system is designed to solve the problem of result error,which is caused by the large number of injections and injection deviations in manual sampling,and to achieve more accurate and reliable detection results.The analyzer requires the entire gas circuit system has pure and continuously running gas,the gas flow rate is required to be stable and tightly sealed,and the flow rate measurement is accurate.Accurate gas flow detection and flow control are the prerequisites for achieving EPC.The gas circuit solution for gas flow detection and control is designed.In the solution,the PIC32MX6 high-performance single-chip microcomputer is selected for WBIM200 high-precision gas flow sensor Pipeline flow monitoring.By controlling the solenoid valve of the gas circuit to achieve the closing of the gas circuit and the adjustment of the gas circuit flow,thereby achieving precise control and monitoring of the gas circuit flow.
作者
陈冲
张银建
CHEN Chong;ZHANG Yinjian(Chongqing Chuanyi Aytomation Co,Lld.,Chongqing 401121,China)
出处
《自动化仪表》
CAS
2020年第12期64-66,71,共4页
Process Automation Instrumentation
