Teledyne 2750 - Portable turbine generator gas analzyer - Manual (Page 11)

Turbine Generator Gas Analyzer Introduction
Teledyne Analytical Instruments 11
Introduction
1.1 Overview
The Model 2750 Turbine Generator Gas analyzer is a portable
microcontroller based three-channel analyzer designed to measure the
concentration of a single gas component in a binary mixture of gases. A
special thermal conductivity cell responds to the difference in thermal
conductivity between the components of a gas mixture and produces a
signal output which is linearized over the specific range of interest. Each
channel is separately linearized for enhanced accuracy. The cell is
maintained at a fixed temperature to minimize any thermally induced
error.
This analyzer is specifically designed for use during the
maintenance of turbine generators. The three ranges allow the user to
monitor the turbine’s blanketing gas as the turbine is in use or during
maintenance. It provides a range of 80%- 100% hydrogen in a
background (impurity) of air for hydrogen purity monitoring. Two
ranges, 0-100% hydrogen in a background of CO
2
, and 0-100% air in a
background of CO
2
are used to monitor the blanketing gas during the
purge cycles. During normal operation the turbine is blanketed with
100% hydrogen. For maintenance the hydrogen is first purged from the
enclosure with CO
2
for fire safety. This process is followed by an air
purge for worker safety. This process is reversed prior to bringing the
turbine back into service.
1.2 Analysis Ranges
The Model 2750 has 3 separate user selectable analysis ranges
controlled by a 3-position rotary switch.
Standard analysis ranges include:
 0-100% hydrogen in CO
2
 0-100% air in CO
2
 80-100% hydrogen in air