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INW - TempHion Instruction Manual
TempHion
TM
Reference Electrode
TempHion’s patented reference electrode is the key to TempHion’s superior downhole/
high pressure performance.
TempHion uses a long capillary pathway, initially fi lled
with reference electrode fi lling solution, to separate the reference electrode chamber
from the solution being analyzed. In addition, TempHion’s reference electrode is
fi lled without
any
air (which is compressible). With this construction, the principle
mechanism that will eventually allow test solution to enter the reference chamber and
contaminate the reference electrode fi lling solution is diffusion – an exceedingly slow
mechanism. Further, while the capillary pathway is narrow by garden hose standards,
its open cross-section is huge compared to the microscopic openings in a conventional
porous ceramic fl uid/fl uid junction. It is therefore much less susceptible to fouling.
Fluid expansion and contraction caused by temperature variations can augment the
effects of diffusion. Nevertheless, TempHion’s proven stability under actual fi eld
conditions is measured in weeks or months, rather than hours or days!
The fi gure below illustrates the construction of the TempHion
TM
reference electrode.
Please note that the capillary pathway between the reference and test solutions is
established using a modifi ed screw thread. This means that the capillary can be easily
opened up for cleaning, refi lling, or other maintenance.
TempHions with standard pH elements, ISE elements, and ORP elements come with
the TempHion Reference Electrode, as described above. The TempHion is also sold
with a wastewater pH element that has a built in reference and so does not use a fi lling
solution.
Reference Electrode Assembly: The modifi ed thread provides
a continuous liquid path between the solution in which the
instrument is immersed and the reference element.
Reference
Electrode
Assembly
Liquid Junction Port
Outer Reference Housing
Capillary Flow path
(Modifi ed Thread)
Reference Electrode
Filling Solution
Reservoir
Reference Element