초록 ▼

An improved oxygen sensing cell, especially of the polarographic type, is intended for use primarily in a gaseous environment. The cell has a cathode located at the bottom of the cell body. The cathode comprises a gold mesh electrode laminated to a thin-film sense membrane. The electrode is thus mad

An improved oxygen sensing cell, especially of the polarographic type, is intended for use primarily in a gaseous environment. The cell has a cathode located at the bottom of the cell body. The cathode comprises a gold mesh electrode laminated to a thin-film sense membrane. The electrode is thus made immobile relative to the membrane, thereby improving the response time and providing for long-term sensor stability. The cell further has a guard electrode for the cathode. The guard electrode operates continuously and scavenges any oxygen molecules which are dissolved in the electrolyte and diffused towards the cathode. As a result, the dynamic range of the cell is substantially increased. The anode comprises a silver wire wound about a spool retained within the main cavity in the cell body. A p.c. board, as well as a compensation membrane, are resiliently retained at the top of the cell body. The body carries conductors for electrically connecting the p.c. board with the anode, cathode, and guard electrode, respectively.

대표청구항 ▼

An oxygen sensing cell, comprising a body having a pair of end portions provided with respective first and second openings therein, the body further having a central bore forming a main cavity communicating with the openings, an electrolyte within the cavity, a compensation membrane mounted over the

An oxygen sensing cell, comprising a body having a pair of end portions provided with respective first and second openings therein, the body further having a central bore forming a main cavity communicating with the openings, an electrolyte within the cavity, a compensation membrane mounted over the first opening in the body, an anode within the cavity in the body, a cathode across the second opening in the body and including an outer permeation sense membrane and an inner porous electrode bonded to the inner surface of said sense membrane, a guard electrode between the second opening and the cathode, said guard electrode being substantially coextensive with and overlying said inner porous electrode, a thin layer of insulating material which is pervious to said electrolyte interposed between said guard electrode and said porous electrode, the opposite sides of said insulating layer being in intimate contact with the adjacent surfaces of said guard electrode and said porous electrode so that said guard electrode is spaced from said porous electrode only by said insulating layer, the guard electrode operating continuously, whereby oxygen molecules dissolved in the electrolyte and diffusing towards the cathode will be scavenged by the guard electrode, thereby substantially increasing the dynamic range of the sensing cell, and means within the body for respectively establishing electrical connections to the anode, cathode and guard electrode.