A SENSOR FOR MEASURING THE CONCENTRATION OF A SOLVENT OR SOLUTE IN A MIXED SOLUTION SYSTEM

• Main Authors: GU, CAIKANG (ELTON), WILKINSON, DAVID P, SHEN, JUN, ZHANG, JIUJUN
• Format: Patent
• Language: English; French
• Published: 12.08.2010
• Subjects: ADHESIVES; CHEMICAL PAINT OR INK REMOVERS; CHEMISTRY; COATING COMPOSITIONS, e.g. PAINTS, VARNISHES ORLACQUERS; CORRECTING FLUIDS; DYES; FILLING PASTES; INKS; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FORELSEWHERE; MEASURING; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; PAINTS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; PHYSICS; POLISHES; TESTING; USE OF MATERIALS THEREFOR; WOODSTAINS

The invention described relates to an apparatus and method for measuring the concentration of a low molecular weight alcohol, in an aqueous liquid feed solution, comprising a first sensor including a hydrophilic capillary tube having an inner diameter, being disposed between two electrodes to form a first capacitor, a second sensor including a hydrophobic capillary tube having the same inner diameter as a capillary tube of the first sensor; said hydrophobic capillary tube having a hydrophobic coating on the inner diameter, being disposed between two electrodes to form a second capacitor, wherein the first hydrophilic and second hydrophobic sensors are dipped to the same depth in the aqueous solution to measure the solution concentration, means for measuring the capacitance of the two capacitors, and control means including a control circuit driven by a computer, wherein the difference in capacitance between the two capacitors is a measure of the concentration of the solution, independent of the depth of dipping of the two capacitors in the aqueous solution. In another embodiment, a single hydrophilic sensor is employed. L'invention concerne un appareil et un procédé pour mesurer la concentration d'un alcool de faible masse moléculaire, dans une solution d'alimentation aqueuse liquide, comprenant un premier capteur comprenant un tube capillaire hydrophile ayant un diamètre interne, qui est placé entre deux électrodes pour former un premier condensateur, un deuxième capteur comprenant un tube capillaire hydrophobe ayant le même diamètre interne que le tube capillaire du premier capteur ; ledit tube capillaire hydrophobe ayant un revêtement hydrophobe sur le diamètre interne, et étant placé entre deux électrodes pour former un deuxième condensateur, le premier capteur hydrophile et le deuxième capteur hydrophobe étant plongés à la même profondeur dans la solution aqueuse pour mesurer la concentration de la solution, un moyen de mesure de la capacitance des deux condensateurs et un moyen de commande comprenant un circuit de commande dirigé par ordinateur. La différence de capacitance entre les deux condensateurs est une mesure de la concentration de la solution indépendamment de la profondeur d'immersion des deux condensateurs dans la solution aqueuse. Dans un autre mode de réalisation, un seul capteur hydrophile est employé.