Functional Principle Of Measurement; Technical Data; Used Chemicals; Dimensional Sketch / Drilling Diagram - Grundfos AQC-D5 Installation And Operating Instructions Manual

5.1 Functional principle of measurement

• Sample water is taken at a representative position and passed
to the measuring cell via an integral filter.
– The water flow rate can be adjusted on the measuring cell.
– A float switch serves to signal a sample water deficiency and
for example trigger an alarm.
• Part of the water is taken from the measuring cell and routed
through the three-electrode assembly.
– The agent to be determined (Cl
noble-metal electrode.
• The material to be determined generates an electric current:
– in the µA range
– proportional to the concentration of the parameter Cl
chlorine)
– The measuring cell is controlled by a potentiostat integrated
into the measuring amplifier.
– An exactly defined potential of the working electrode is
retained by means of the third electrode (reference
electrode). This results in a linear response for the
measuring cell as well as a stable zero point for the
measurement.
• The measuring amplifier Conex
– amplifies the current
– calculates it using the calibration parameters
– displays the concentration as a numerical value
– controls a gas dosing unit or a dosing pump as final control
element.
A water sample without buffer solution can be taken at the sample
water tap. This tap is located before the measuring cell.
) is converted at the
2
(total
2
®
DIA:

6. Technical data

Measured
Free chlorine
parameters
Sample water
0 °C to +40 °C
temperature
Inlet pressure 0.2 bar - 6 bar (free outlet)
Permissible
ambient +5 °C to +40 °C
temperature
Sample water flow
Minimum 4.5 l/h
rate
Wetted parts
PMMA, PVC, steel, PTFE, EPDM
materials
Electrode materials Glass, PVC
Inlet: for PVC tube 6/12 mm or PVC pipe
12 x 1.2
Connections
Outlet: for PVC tube 6/12 mm or PVC pipe
12 x 1.2
Sensitivity < 10 ppb
Accuracy < ± 5 % of full-scale value
Repeatability < ± 3 %
Response time T approximately 60 seconds
90
Measuring range
for measuring 0 - 20.0 mg/l
parameter Cl
2

6.1 Used chemicals

The following chemicals are used:
• 91835799 (549-300), buffer solution: ready for use
• buffer solutions consumption: < 360 ml/day
– One container lasts about two weeks.
For further data, see the installation and operating instructions
enclosed with the components.

6.2 Dimensional sketch / drilling diagram

Dimensional sketch
Fig. 2
7