Overview; Navigator 550 Hydrazine Wet-Section - ABB Navigator 550 Operating Instructions Manual

Navigator 500
Hydrazine analyzer

2 Overview

2.1 Navigator 550 hydrazine wet-section

The Navigator 550 hydrazine wet-section has been designed for use with an ABB Navigator 540 transmitter to provide continuous
monitoring and control of power station boiler feed water, using an electro-chemical sensor to measure the amount of hydrazine in
the boiler water. The information provided by the wet-section can be used to avoid expensive overdosing of hydrazine or costly
damage to boiler plant due to under-dosing of hydrazine.
The hydrazine wet-section contains a measurement sensor (that can be refurbished), calibration valve, dosing chamber, delay /
mixing coil, constant-head unit and electronics that store the calibration data and calculate the concentration reading. Reagent
solution* to raise the pH of the sample is added via a microporous disc. During the calibration sequence, a solenoid valve switches
the sample to drain and enables the standard solution to flow through the sensor instead. A calibration can be initiated manually
when required or automatically with programmable daily frequency ranges, from 1 to 7 days and 1 to 8 weeks.
Reagent and standard solution tanks are located in the upper half of the wet-section. The measurement range specification is 0.0 to
1000 ppb.
*For information about reagent solutions, contact the local ABB representative.
Hydrazine sensor (red)
Pt1000 temperature
sensor (blue)
Calibration
solution tubing
Hydrazine sensor
mounting clip
Hydrazine sensor
Reagent dosing chamber outlet (base)
Fig. 2.1 Navigator 550 hydrazine wet-section – main components
6
Calibration solution tank
PCB cover / PCB
Delay /
Mixing coil
Drain (hydrazine sensor)
Reagent dosing
chamber (base)
Solution
filler caps
Reagent solution tank
Constant-head unit
Calibration valve assembly
Drain tube (emergency) –
constant-head unit
Reagent tube – reagent tank to
dosing chamber (top)
Sample tube from solenoid
valve to dosing chamber (base)
Sample inlet
Drain tube
(constant-head unit)
Drain outlet
OI/AHM550–EN Rev. A