Evoqua WALLACE & TIERNAN SFC, Original Instruction Manual

Page: 55 / 288

SFC
Functions
4.
55
4.2.5 Conductivity Measurement
The conductivity measurement represents a composite parameter
for the total mineralization of water. This measurement depends
heavily on the temperature, therefore a temperature sensor is
integrated directly into the conductivity sensor. The measured
value is always indicated in relation to a certain temperature value.
The international reference temperatures are 20°C or 25°C.
Picture 4 Sensor measuring module
The conductivity measuring system consists of:
• Conductivity module with terminal strip
• Conductivity sensor
• Electrode support for pressurized/non-pressurized assembly
The LF325 conductivity measuring cell consists of a 4-electrode
system with integrated temperature sensor. The electrodes are
made of graphite and are therefore very robust and abrasion-
resistant. The cell constant is 0.48 cm
-1
.
The conductivity module must be installed in the module slot of the
SFC. Various controller functions are available depending on the
application. The electrode can be installed in the flow block
assemblies DEPOLOX
®
5/DEPOLOX
®
Pool/DEPOLOX
®
4 or in a
separate Y-style flow through assembly. The electrode support
must also be used if installing the pressurized version in the flow
block assembly.
Installation notes
Ambient conditions
The following must be taken into account when installing the
conductivity measurement:
• Select the sample water extraction point that guarantees
bubble-free sample water flow.
• This does not require a certain flow rate.
• The electrode must be immersed at least 4 cm deep into the
sample water.
• If the conductivity electrode is not installed right next to the
SFC, the measuring cell cable can be lengthened up to no
more than 50 m using a connecting box and a six-core,
shielded cable (see 8. “Complete Units, Retrofit Kits and Spare
Parts”).
• The terminal strips must be used with a right-hand direction of
connection. Information on connecting the sensor to the
conductivity module can be found in the wiring diagrams in 9.
“Wiring Diagrams”.