Electrodes
Glass diaphragm electrodes use a
reference electrode, suspended in a
buffer solution of pH7 - that is compared to the measuring electrode
and as such this design is used for
a wide range of applications. For
more robust applications single
element electrodes made from
enamel-coated steel or a polymer
that use pH sensitive coatings are
also available.
Bürkert uses a modular system
that allows process engineers to
build the most suitable pH sensing system, depending on the
application. A variety of probes
designed to operate in varying conditions and media can be combined
with PT1000 temperature sensors
and connected to a transmitter / controller such as the Type 8619 multiCELL. Combined with a choice of
fittings and sealing materials as well
as EHEDG certification, the product
range can be specified to suit most
applications within the food industry.
In general glass pH electrodes are
not suitable for food applications due
to the risk of broken glass fragments
contaminating the process. Further-
more, many designs of pH electrode
need to be removed from the process
stream before the CIP process can be
completed which requires expensive
retraction systems to be employed,
creating extra work and inconvenience for the end user.
A variety of probes and temperature sensors designed to
operate in varying conditions and media can be connected
to a transmitter / controller such as the Type 8619
multiCELL seen here mounted into a stainless enclosure.
One solution could be the Type 8201
pH measuring system, which employs a hygienic, robust and glassfree design that can withstand high
temperatures and can be sterilised in
situ. In addition, the smooth enamel
external surface of the probe inhibits
the process medium from sticking to
it and is very easy to clean.
By using industry standard signals,
these pH sensors can either be integrated into an existing process control system or used in conjunction
with other control components. This
can provide localised feedback for a
closed loop control system, for example to ensure the correct dosing of a
product with pH sensors both before
and after the process.
Material specification of the sensor
body and the sealing components
can also play an important role in
the performance of the pH sensor
within the wider process control
environment. This is particularly
true when dealing with extremes
of pH which can be highly reactive
and corrosive. Sensor manufacturers with specialist knowledge
in this area should be available to
support customers to ensure that
both process and hygiene control
are properly managed.
The wid H