Teledyne 9110TH - Nitrogen Oxides Analyzer - Manual (Page 291)

Troubleshooting & Repair Model 9110TH NOx Analyzer
Teledyne Analytical Instruments 271
8.3.6. O
3
GENERATOR
The 9110TH/M uses a corona discharge (CD) tube for creating its O
3
. Corona discharge
generation is capable of producing high concentrations of ozone efficiently and with low
excess heat. Although there are many cell designs, the fundamental principle remains
the same (Figure 8-9).
Figure 8-9: Ozone Generator Principle
The 9110TH/M utilizes a dual-dielectric design. This method utilizes a glass tube with
hollow walls. The outermost and innermost surfaces are coated with electrically
conductive material. The air flows through the glass tube, between the two conductive
coatings, in effect creating a capacitor with the air and glass acting as the dielectric. The
layers of glass also separate the conductive surfaces from the air stream to prevent
reaction with the O
3
. As the capacitor charges and discharges, electrons are created and
accelerated across the air gap and collide with the O
2
molecules in the air stream
splitting them into elemental oxygen. Some of these oxygen atoms recombine with O
2
to O
3
.
The quantity of ozone produced is dependent on factors such as the voltage and
frequency of the alternating current applied to the CD cells. When enough high-energy
electrons are produced to ionize the O
2
molecules, a light emitting, gaseous plasma is
formed, which is commonly referred to as a corona, hence the name corona discharge
generator.