ABB AP100 pH/Redox (ORP) cartridge sensors
The cartridge
The cartridge sensing system has a proven track record in a
wide range of applications. New features such as the low
resistance ‘blue-glass’ and the small-bore flow version for low
volume samples reinforces the performance and extends the
applications that can be fulfilled using this versatile and well tested system.
Manufactured in glass-coupled polypropylene, the all-in-one
sensor can be supplied for flow-through, dip and submersible
applications.
Flow systems – can be supplied with a choice of process
connections and materials to meet the demands of the
sample to be measured. The bayonet snap-fit enables rapid
and convenient access for calibration – just twist and turn and
the sensor is released for easy and quick calibration.
Pipeline adaptor (7670/063) – is available to enable the
sensor to be inserted directly into a pipe.
Dip systems – available in 1, 2 and 3 m (39, 78 and 117 in)
lengths for use in open channels and tanks.
Submersible systems – available with an integral sealed
connection cable enabling the sensor to be completely
submerged – ideal for boreholes or where there is a large rise
and fall in the sample to be measured. Provision is made for a
support chain to be attached to the system. A wide range of
standard cable lengths is available.
Water-wash options – available for flow and dip systems
where coating of the pH glass causes maintenance issues.
Water-wash has proven very successful in many applications.
Detachable cables – an option that makes replacing the
sensor a simple, easy-to-do operation. The use of IP67 plug
and socket connectors ensures that problems caused by
moisture ingress do not occur and enables reliable operation
in the most demanding applications.

The cartridge
Double-junction PTFE reference – a key feature to minimize
the risk of blocking of the junction and protect against
poisoning of the electrolyte.
Supplied ready-to-go – fitted with a wetted teat to ensure
the sensor is in optimum condition and requires no
preconditioning prior to installing and commissioning.
Small-bore flow systems – ideal for applications where only
small sample volumes are available (between 100 and 500 ml/
minute [0.176 and 0.88 pints/minute]) for continuous analysis.
These flow systems are offered in a choice of two materials,
stainless steel and Delrin, both widely used on low
conductivity water. Being small and compact they help to
keep the panel size to a minimum when used on multi parameter
ackages and are a very cost effective solution.
Low resistance glass – a unique glass designed particularly
for cold water samples where conventional sensors perform
sluggishly due to low sample temperatures (below 10 °C down
to 0 °C [below 50 °F down to 32 °F]). This sensor is used
extensively on potable water treatment works where the
sample temperature is commonly below 10 °C (50 °F). A
further benefit of the low resistance glass is improved speed
of response where the sample has a low conductivity (less
than 100 µS/cm and down to 20 µS/cm).
Water-wash systems – have proven extremely successful on
potable water treatment plants where iron or manganese
coat the glass electrode, increasing maintenance levels. The
frequency and duration of the clean is controlled via the
AX400 Analyzer and during the clean cycle the current output
and alarms are frozen to prevent spurious alarms.
Redox (ORP) sensors – supplied in flow, dip and submersible
systems, with water-wash options available for flow and dip
systems. They are used widely in the treatment of waste
water and, in particular, for electro-plating for the treatment
of cyanide and chromate waste liquor.
Reference electrode refurbishment kit
To allow the maximum working life of the sensor to be
achieved, a refurbishment kit is available (Part No. 7670/088).
The kit contains a replacement PTFE liquid junction, a bottle
of 3.5M KCl reference electrolyte solution and pipette, a liquid
junction removal/refitting tool and all necessary O-rings.
Many sensors are replaced because the liquid junction
becomes blocked due to the nature of the sample or because
the electrolyte solution is exhausted. Replacing the junction
and electrolyte extends sensor life and reduces the cost of
ownership.
