Electrolytic sensor for measuring the content of gas in a fluid

A sensor for measuring the content of a gas in a fluid using a liquid or gel electrolyte, comprising:

• a sensing electrode layer comprising a first substrate layer of impermeable material having a groove and a sensing electrode having an exposed portion formed on said first substrate layer in the groove,
• a further electrode layer comprising a second substrate layer of impermeable material and a further electrode formed on said second substrate layer, the sensing electrode layer and the further electrode layer being bonded together in superimposed relation in a laminated construction and defining therebetween an electrolyte reservoir cavity for containing an electrolyte, contacted by the further electrode, and
• a third substrate layer having a gas-permeable membrane extending across a window provided in the third substrate layer, the third substrate layer and the sensing electrode layer being bonded together in superimposed relation in a laminated construction so that a portion of the groove therebetween defines a reaction cavity for containing an electrolyte wherein the exposed portion of the sensing electrode is in the reaction cavity, said window communicating between an exterior of the sensor and the reaction cavity, said reaction cavity being smaller in volume than said reservoir cavity and communicating with said reservoir cavity, and said reaction cavity and said reservoir cavity containing the electrolyte with a portion thereof held between the gas permeable window and the exposed portion of the sensing electrode.

A laminated sensor construction comprising:

• a window layer, having a first gas-impermeable substrate and a gas-permeable membrane extending across a window communicating with an exterior of the sensor in said first substrate;
• a sensing electrode layer having a groove formed therein superimposed on and fixed to the window layer and having a second gas-impermeable substrate with a sensing electrode having an exposed portion that extends into a portion of the groove, wherein the groove portion forms a reaction region exposed to the gas-permeable window;
• at least one reservoir layer superimposed on and fixed to the sensing electrode layer, said reservoir layer having a third gas-impermeable substrate with at least one through-aperture, and
• a further electrode layer having a fourth gas-impermeable substrate superimposed on and fixed on the reservoir layer, whereby opposing surfaces of the further electrode layer and the sensing electrode layer extending over the at least one through-aperture of the reservoir layer define an electrolyte reservoir cavity communicating with the reaction region through the groove formed in the sensing electrode layer, the reaction region having a smaller volume than that of said reservoir cavity, said reservoir cavity and said reaction region containing the electrolyte and holding a portion of the electrolyte in contact with the exposed portion of the sensing electrode and the gas-permeable window, and a further electrode contacting the electrolyte reservoir cavity.