Replacement pH Sensors
pH Electrodes, and pH Probes
The biggest changes in pH sensor technology have been in the mountings and in the change from the P90S refillable electrodes to the newer PS90S sealed electrodes introduced in 1999. At this time the old calomel reference which contained mercury was discontinued. The original refillable pH electrode system had a 5/8” BSP thread which was changed to prevent the new sealed pH Sensors being fitted to the refillable dip tubes and being filled with the liquid salt bridge solution.
The original pH electrode holders made by many of the international instrument companies with separate glass reference and auto temp comps. These have now been replaced with sealed combination pH electrodes - which often outperform the originals and are very much simpler to maintain.
pH Probe Model P90S/R90S
Model P90S/R90S pH electrode / redox electrode system for submersion into open tanks, pits or sumps. Original systems were filled with 3.8 molar KCL solution and had a sight glass at the top. The electrode mounted via a 5/8” BSP thread now obsolete as the electrode contained mercury. Manufacture ceased in 1999.
Replacement pH Probe
Replaced with PS90S pH probe sealed or RS90S Redox probe sealed - which has a larger thread to prevent fitting the new electrode to the flooded holder. The pH Electrode / Redox Electrode is identical in size to the original, please advise the length required.
Model PES2 - PES4 or PES7
Model PES2 - PES4 or PES7 pH electrode system for submersion into open tanks, pits or sumps. Manufactured from PVC or Kynar and Polypropylene some had a stainless steel riser tube fitted with LB J-Box on the electrode top. (Commonly called the walking stick pH electrode). Manufactured from 1984, many still in use.
Replacement pH Sensor
Replacement pH Sensor in Kynar (PVDF) PN 3637-10B Replacement mV electrode in Kynar (PVDF) PN 3698-10B
Complete systems can be replaced with the PS100S pH probe or the PRS100S Redox probe, note the flange and riser tube are a larger diameter.