Teledyne 3010PA - Split architecture percent oxygen analyzer - Manual (Page 63)

2-2: Part II
2 Operational Theory Model 3010 P
analyzed. The Micro-Fuel Cell is therefore a hybrid between a battery and a
true fuel cell. (All of the reactants are stored externally in a true fuel cell.)
2.2.2 Anatomy of a Micro-Fuel Cell
A Micro-Fuel Cell (MFC) is a cylinder only 1¼ inches in diameter and
1 inch thick. All are made of an extremely inert plastic, which can be placed
confidently in practically any environment or sample stream. The cell is
effectively sealed, although one end is permeable to oxygen in the sample
gas. The other end of the cell is a contact plate consisting of two concentric
foil rings. The rings mate with spring-loaded contacts in the sensor block
assembly and provide the electrical connection to the rest of the analyzer.
Figure 2-1 shows the external features of a typical cell.
Figure 2-1: Micro-Fuel Cell
Refer to Figure 2-2, Cross Section of a Micro-Fuel Cell, which illus-
trates the following internal description.
Figure 2-2. Cross Section of a Micro-Fuel Cell (not to scale)
At the top end of the cell is a diffusion membrane of Teflon, whose
thickness is very accurately controlled. Beneath the diffusion membrane lies
the oxygen sensing element—the cathode—with a surface area almost 4 cm
2 .