Choice without Compromise - 31/03/2011

Tough and durable sensors for on-line pH measurement

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.certificates of cell constant accuracy can be supplied on request.

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 packages 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.The AC200 series of cells provide highly accurate and reliable inline conductivity measurements up to 20 bar (290 psi) and 200°C (392°F). Typical applications are power plants, ionexchangers, reverse osmosis and chip cleaning.













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