Benchtop fermenters are usually autoclaved at 120-135 °C prior to use. If pH or ORP monitoring is required then the electrodes must be calibrated and then autoclaved with the complete system. This puts considerable demands on the electrodes.

Thermo Scientific has developed a unique formulation of pH glass for this purpose. This stands up to the rigors of autoclaving much better than conventional pH glass with a significantly lower change in calibration values. The silver/silver chloride reference system has to be of more robust construction to prevent degradation of the silver wire. A viscous formulation of reference electrolyte is used to reduce loss. Extra seals are used in the cap construction that is fully steam resistant. Electrodes are supplied complete with a blanking cap.

Pilot plant and process fermenters are usually steam sterilized with all instrumentation in place.  Thus it is only the tip of the electrode (the length inside the fermenter) which is subjected to the high temperature.  This results in a longer lifetime for the electrode but a similar, robust construction is still required.  To prevent ingress of broth, positive pressure is provided by means of a housing on the outside of the fermenter.  Different Thermo Scientific electrodes fit all the major designs on the market today.

 Russell Fermenter Electrodes

 Product#

 Description

 Best for

 ACWL 

 Autoclavable combination pH electrode

 Benchtop fermenters

 ACWL/IS 

 Autoclavable combination pH electrode with inclined sidearm

 Benchtop fermenters

 PHT08/PHT16/PHT02 

 Steam sterilisable, pressurisable, combination pH electrode

 Process and pilot plant fermenters

Specifications:

Temperature range :

0-130°C

Reference junction :

Ceramic frit

Reference electrolyte :

S00R

Connector type :

S7

pH range :

0-14