In order to draw high quality low loss optical Fiber with the required strength and attenuation the temperature of the drawing tower furnace must be stable and precisely controlled.

The furnace lining can get close to melting point so its temperature is monitored and used as the heating control parameter.

Measurement Problems Graphite resistance and Induction-heated zirconia furnaces operating at high temperatures, typically 2200°C/4000°F, make contact methods of temperature measurement impractical.

The thermometer requires a small target size to view between the coils in an induction heated furnace, or sight down a narrow tube on to the zirconia susceptor.

In the case of a graphite resistance type furnace the thermometer has to sight through a quartz window, down through a narrow tube onto the heating element.

Experience has shown outstanding benefits by using short wavelength thermometers, for this application in order to achieve maximum accuracy.

A silicon cell detector gives high stability, rapid response and high rate of change of output with temperature.

A small target size is offered, with a measurement spot size of 4mm/0.15in diameter at the focus distance of 450mm/17.7in.

The thermometer provides high level signal to noise output for retransmission to a readout or control system.

Individually calibrated thermometers are available with traceability to National Standards. UKAS or NIST Calibration certificates are available.

Features

• 2m light guide length
• Small target capability
• Rugged, flexible, modular design
• Accurate, reliable, drift-free measurement
• Industry standard outputs to suit any process monitoring, recording or control system
• Standard industry mounting