Rosemount PERpH-X High Temperature (HT) pH sensors incorporate several design innovations that prolong the life of the pH sensor in difficult hot processes. High temperatures cause deterioration of the glass pH sensing membrane, depletion of the reference electrolyte, and thermal stress on all sensor components.
The Rosemount PERpH-X high performance pH sensors incorporate several design innovations that prolong the life of the sensor in difficult applications. The 3300/3400 sensors 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 minimizing maintenance and lowering the total cost of ownership.
The AccuGlass pH glass electrode provides exceptional resistance to thermal degradation, even at temperatures above 140C. This translates to less breakage from thermal stress or shock and improved speed of response for fast and accurate calibrations even after months of service. The beneficial pH traits of near theoretical response, even at extreme values, and minimal hysterisis carryover from previous AccuGlass designs. A slotted tip protects the glass bulb from direct impacts while in service and during calibration.
The PERpH-X sensors utilize an enhanced double junction reference electrode that excels in harsh applications. The specially designed porous Teflon liquid junction has a large surface area to maintain a steady reference signal in dirty fouling applications. The KCl based reference electrolyte is a temperature insensitive viscous gel that resists the fouling caused by thermal or pressure cycling. The porous Teflon reference junction can be easily replaced in the event that it becomes fouled or plugged. 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 problems, 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 minimizing the depletion or poisoning of the primary reference. Specialty electrolyte solutions are available for certain troublesome measurements.
The successful measurement of pH requires more than just a great pH glass electrode, the AccuGlass electrode, and a great reference electrode, the double junction porous Teflon reference; it requires that these electrodes are built into a sensor that can withstand the demanding environments present in Chemical Processing Industries. The 3300/3400 pH sensors accomplish this through the use of a molded Ryton@ body housed in a titanium tube. The chemically resistant construction is further enhanced by the choice of EPDM, Viton® or Kalrez orings.
Viton® is a registered trademark of DuPont Performance Elastomers.