Non-obvious Problems in Clark Electrode Application at Elevated Temperature and Ways of Their Elimination

Figure 4

Scheme of warming-up (wavy arrows are heat transfer) of the measuring cell up to the operating temperature: (1) is oxygen sensor (cathode is not shown), (2) is measuring cell, (3) is thermostat, (4) is heating element, (5) is connecting tubes, (6) is magnetic stirrer, (7) is thermometers, (8) is mounting place of thermocouples, (9) is heat carrier, (10) is electrolyte of oxygen sensor, and (11) is incubation medium. 𝑡₁, 𝑡₂, and 𝑡₃ are points of temperature control. Warming-up of the system is carried out in the direction of the thermostat-medium-electrolyte. In the state of thermal equilibrium, temperature of the incubation medium (11) is appreciably below the temperature of the heat carrier (9) into the thermostat (3) due to heat losses in the connecting tubes (5). The temperature of the electrolyte (10) is even lower due to the cooling of the oxygen sensor body (1) by ambient air.