SENSOR

摘要

Referring to Figures 1 and 2, the illustrated sensor cell comprises a body (1) defining an annular bore therethrough. A porous disc (2) formed from high density polyethylene is received within the body and pressed against a shoulder defined by the body by an O-ring (3). The ring (3) is compressed against the disc (2) and against the cell body (1) by an electrolyte pot (4) which is retained within the body by a spring clip (5). As shown in Figure 1, the pot (4) defines an inverted cup the open end of which located above the disc (2). Thus the interior of the pot may be filled with an electrolyte (6). A reference electrode (7) extends through the base of the pot (4) so as to electrically contact the electrolyte (6). The reference electrode may be formed from for example silver or silver chloride. Working and counter electrodes are formed on the surface of the disc (2) facing away from the electrolyte, the disposition of those electrodes being shown in Figure 2. The working electrode (8) is generally circular and an annular counter electrode (9) extends therearound, the two electrodes being connected to contact pads (10) to enable their connection to appropriate electrically conductive wires. The working electrode (8) is formed from a film of copper and the counter electrode (9) is formed from copper. The electrodes (8 and 9) may be in the form of printed tracks. Connections may be made to the electrode (8 and 9) in any convenient manner, for example by arranging steel pins in the body (1) which define points that bear against the contact pads (10). The pot (4) is filled with a conducting electrolyte such as glycerol or KCl.