Brochure

The new pH measuring instruments with innovative probe engineering
2
Measurement of the pH value plays an
important role in many areas. Anywhere where
there are chemical and biochemical reactions,
the pH value has an important indicator
function.
Even though the engineering has been
established on the market for years, there are
still some application problems:
· Short life span of pH probes due to glass
breakage and dirt ingress, for example
· Sensitivity to dirt of the pH probe resulting in
incorrect measurements
· Spillage of storage solution
· Handling problems when calibrating
· Lack of one-hand penetration pH probes for
liquid and viscoplastic substances
· Lack of combined temperature and pH
measurement
Together with experts from industry and the
trades, Testo has developed innovative
solutions.
Instead of a liquid electrolyte, Testo pH probes
have a gel electrolyte as a reference substance
for pH measurement which facilitates the use of
a hole diaphragm between the measurement
electrode and housing in place of the micro-
porous structure usually used in pH probes.
The micro-porous structure becomes blocked
up more quickly, similar to a finely woven sieve,
consequently requiring regular service which in
return results in a shorter life.
Due to the large volume of gel electrolyte and
the hole diaphragm, Testo pH probes are not
only leakproof, they are almost completely
maintenance-free, robust and and unaffected
by dirt and dust.
The combination of the pH penetration tip and
temperature probe in a one-hand instrument for
accurate and fast temperature compensation is
unique. Consequently, accurate readings are
guaranteed in all ambient conditions.
With the development of different, breakproof
probe geometries, Testo is making available
special solutions for liquid as well as for
viscoplastic substances.
The leakproof storage solution is also new.
pH probes must be stored in moist conditions,
when not in use, in order to prevent the glass
membrane coating around the measurement
electrode and the diaphragm from drying out.
Pure water alone should not be used since
water would release the conducting
components contained in the probe
electrolytes. A potassium chloride solution is
usually used for this purpose. As with every
liquid, it can leak which, particularly in the food
branch, can lead to contamination of raw
foodstuffs or products.
Testo, with its new gel storage, has eliminated
this disadvantage. The potassium chloride
solution is available in a container in gel form.
What doesn’t drip can’t leak!
pH1 probe head for liquids
pH2 probe head for semisolid
substances
Interchangeable probe
The potassium chloride solution
bonded in the gel cannot leak.