An Energy-Efficient Self-Regulating Heater for Flow-Through Applications

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• 作者：Purnendu K. Dasgupta ; Ellis L. Loree ; Jianzhong Li ; and Zhang Genfa
• 刊名：Analytical Chemistry
• 出版年：2003
• 出版时间：August 1, 2003
• 年：2003
• 卷：75
• 期：15
• 页码：3924 - 3928
• 全文大小：159K
• 年卷期：v.75,no.15(August 1, 2003)
• ISSN：1520-6882

文摘

In many experiments, a flow-through heating arrangementis needed to reduce reaction time. Often the reactionconditions require inertness of the wetted material. Heatedreactors based on polymeric tubing, notably PTFE, arethe most common, and such reactors are typically usedin a manner in which they are put in a heated bath or anotherwise thermally conductive potting in which a heaterand a temperature sensor are embedded for heating andtemperature control. Polymeric tubes are poor conductorsof heat; as such, most reactors of this type have very poorenergy utilization. We describe here heated flow-throughreactors where a wire runs through the entire length ofthe tubular reactor and where the wire is directly electrically heated. The wire may or may not be electricallyinsulated. If the exterior of the tube is well insulated, theenergy efficiency of such a reactor in heating the fluid ofinterest is nearly unity. This makes it most suitable forbattery-powered applications. If an appropriate wire witha significant temperature coefficient of resistance ischosen, monitoring the current through the device atconstant applied voltage indicates the effective meantemperature of the device and thus allows effective temperature control without an additional sensor/controllerwith essentially instantaneous response. Temperaturecontrol within ±0.4 C at a mean temperature of 65 Cand within ±0.9 C at 87 C have been achieved.