Range Of Application; Construction And Function - ProMinent DULCOTEST PAA 1-mA-200 ppm Operating Instructions Manual

Range of application / Construction and function
Construction of
the measuring cell The PAA measuring cell consists of 3 main components, the upper
Function of
the measuring cell The PAA measuring cell is a diaphragm-covered, amperometric
30
4

Range of application

IMPORTANT
• Non-compliance with operating conditions specified in
the technical data (see section 14) could lead to a measur-
ing error and to a dangerous over metering within a con-
trol system.
• The measuring cell is not suitable for checking for the
absence of peracetic acid.
Peracetic acid is used particularly in the food and drinks
industry but also as a disinfectant in the areas of cosmetics,
pharmaceuticals and medicine. The ongoing measurement and
control of peracetic acid is therefore necessary when there are
high demands placed on disinfection and quality assurance.
Typical applications for peracetic acid are found in CIP (Clean-
ing In Place) and rinsing processes (drinks manufacturing).
5

Construction and function

section, the electrode shaft and the diaphragm cap (see fig. 1). The
electrolyte-filled diaphragm cap represents the measuring chamber
into which the measuring electrodes are immersed.
The measuring medium is sealed by a diaphragm in the measuring
chamber.
The electronic amplifier is embedded in a synthetic compound in
the upper section of the shaft.
The measuring cell has a passive 4-20 mA two-wire interface. Po-
wer is supplied externally from a measuring and control system, e.g.
®
DULCOMETER D1C for the measured variable peracetic acid.
two-electrode measuring cell. A gold cathode is used as a collector
and a silver halogenide coated anode as a counter and reference
electrode.
The peracetic acid contained in the sample water diffuses through
the diaphragm. The constant polarisation voltage between the two
electrodes causes the electrochemical reaction of the peracetic
acid on the collector. The resulting current is measured as a primary
signal (amperometric measurement principle). This is proportional
to the concentration of peracetic acid within the area of operation of
the measuring cell. The electronic amplifier within the measuring cell
converts the primary signal into a temperature compensated 4-20
mA output signal, which is displayed in the DULCOMETER
for the measured variable peracetic acid.
®
D1C
ProMinent ®