2
1
INTRODUCTION
Fig. 1.1 AV400 Series Systems
1.3
AV400 Series Systems – Fig. 1.1
Note.
An AV400 System is supplied factory-
configured as a matched system with each component
bearing the same serial number. If any part of a system
is replaced (transmitter or sensor[s]),
a complete
factory re-calibration must be carried out
– see
Section 7.
•
The
AV410
and
AV411
low range monitors are primarily for
use in potable water applications, such as monitoring the
effectiveness of the coagulation control, THM precursor
detection and final treated water quality.
Range:
0 to 20mgl
-1
C
maximum.
•
The
AV420
and
AV422
high range coagulation monitors are
designed for use in potable water treatment plants to predict
the coagulant dose to be applied to the raw water and to
detect the rise in DOC from algal bloom toxins.
Range:
0 to 100mgl
-1
C
maximum.
1.1
Introduction
UV
Warning.
The sensor emitter module
contains a high intensity xenon strobe lamp that emits
ultraviolet (UV) radiation.
This must
NOT
be viewed
with the naked eye and must
NEVER
be operated
while outside the sensor
. Under normal operating
conditions, it is not possible to see the light source but,
if the sensor is dismantled with electrical power applied,
it may be possible to expose the eyes to the strobe
flash.
Many dissolved organic compounds (DOC) found commonly in
potable water absorb ultraviolet radiation. These include Humic
Acids, that gives water a characteristic yellow color, and
dissolved organics, that result in the formation of
Trihalomethanes (THMs).
The monitor is designed for use as a surrogate color monitor,
coagulation monitor/controller and to monitor for THM
precursors in potable water treatment plants.
1.2
Principle of Operation
The broad-spectrum, high intensity xenon strobe lamp, housed
in the emitter module, generates pulses of light that pass
through the sample water in the flowcell to a filtering and
detection system, contained in the receiver module. The
received light pulses are analyzed at two wavelengths; the
measurement wavelength of 254 nm and the reference
wavelength of 405 nm (at which the sample constituents of
interest do not absorb). This dual light path system provides
information that enables the measured value to be corrected for
any turbidity due to suspended matter in the sample. The
monitor is calibrated with a pure solution of a suitable organic
compound of known carbon content.
An automatic, microprocessor-controlled, dual-wiper system,
housed in the cleaner module, cleans the flowcell optical
windows periodically to ensure that the sensor remains
functional. Samples containing large solids and/or very high
concentrations of solids must be pre-filtered.
7320 100
AV400
AV400
7320 200
Low Range System
High Range System
