The Rosemount Analytical high performance pH sensors incorporate several design innovations that prolong the life of the sensor in difficult applications. The 3300/3400 series were engineered for and evaluated in high temperature processes, which provide the harshest test of pH sensor design. This process validated the improved durability of the pH glass electrode, the increased stability of the reference electrode and the overall reliability of the mechanical design. The resulting sensors live longer, respond faster and drift less thereby minimising maintenance and lowering the total cost of ownership.
The ACCUGLASS pH glass electrode provides exceptional resistance to thermal degradation, even at temperatures above 140°C. This translates to less breakage from thermal stress or shock and improved speed of response for fast and accurate calibrations. The high measurement accuracy and minimal hysteresis have been carried over from previous ACCUGLASS based designs. A slotted tip protects the glass bulb from direct impacts while in service and during calibration.
The sensors utilise an enhanced double junction reference electrode that excels in harsh applications. The KCl based reference electrolyte is a temperature insensitive viscous gel that resists the fouling caused by thermal or pressure cycling. The specially designed porous Teflon liquid junction has a large surface area to maintain a steady reference signal in dirty fouling applications. In the event that it becomes fouled or plugged the reference junction can be easily replaced. With the junction removed the outer reference electrolyte can be recharged using a gel filled syringe supplied in the refill kit, available as an accessory.
Most pH measurements fail due to reference electrode irregularities, fouled electrolytes or clogged reference junctions. Replacing a clogged junction or recharging the electrolyte will rejuvenate most failed sensors. Preventive maintenance on the reference electrolyte can dramatically extend the ultimate life of the sensor by minimising the depletion or corruption of the primary reference. Specialty electrolyte solutions are available for troublesome applications.
Successful pH measurement in harsh chemical applications depends on high quality measuring and reference electrodes packaged together in a robust housing. The 3300/3400 pH sensors accomplish this through the use of a moulded Ryton body housed in a titanium tube. The chemically resistant construction is further enhanced by the choice of EPDM, Viton or Kalrez O-rings. The high performance pH sensors have been evaluated in high-temperature situations and other chemically aggressive, dirty or fouling processes. According to Rosemount the design provided superior performance in most applications.
Models 3300HT and 3400HT are equipped with a 3 m cable for wiring directly to an analyser, transmitter or remote junction box. The Model 3400HT retractable sensor is also available with a shorter cable configuration for use with a sensor head junction box attached to the sensor tube via a compression fitting. A Variopol VP connector is also available to facilitate quick sensor replacement.
When the sensors are installed more than 3 m from the transducer a remote preamplifier should be used to protect the integrity of the high impedance pH signal. All 3300HT and 3400HT sensors are compatible with Rosemount Analytical's Models 54e, 1055, 1056, 5081, Xmt instruments and instruments from other suppliers that do not require a preamplifier in the sensor.
For more information contact Santosh Pillay, Alpret Control Specialists, +27 (0)11 249 6700, [email protected], www.alpret.co.za
| Tel: | +27 11 249 6700 |
| Fax: | +27 11 474 8368 |
| Email: | [email protected] |
| www: | www.acs-autocon.com |
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