Product category:
pH and conductivity meters
News Release from: Jumo Instrument Company | Subject: pH sensors
Edited by the Laboratorytalk Editorial
Team on 08 October 2004
Measuring pH under continual stress
pH electrodes with an annular gap diaphragm and a solid electrolyte to provide high reliability and high quality in industrial measurement
pH sensors are frequently subjected to a considerable amount of continuous stress in industrial measurement technology In such situations, the user needs reliable sensors of high quality
This article was originally published on Laboratorytalk on 24 May 2004 at 8.00am (UK)
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Jumo has developed a new electrode especially for applications in heavily polluted media, emulsions, dispersions, or for use in media containing proteins and sulphides, as an alternative to electrodes incorporating a ceramic or PTFE diaphragm, also for heavily contaminated municipal or industrial wastewater.
The electrodes use a polymer-based solid electrolyte.
In addition, they feature an annular gap diaphragm that is sby a high degree of immunity to interference.
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The annular gap construction and use of a solid electrolyte ensure that the diaphragm cannot become clogged.
The measurement remains stable over a lengthy period, even in heavily polluted media.
For application in general aqueous solutions (swimming pool monitoring, drinking water treatment, aqueous media without any dirt charges, media containing few ions), pH sensors with gel filling and ceramic diaphragm can continue to be used.
As a result of the direct contact between the electrolyte and the medium, an increased thinning effect has to be expected in such media with solid-electrolyte electrodes, which would considerably reduce the operational life of the electrode.
The solid electrolyte is free from silver chloride, which makes it insensitive to sulphide ions.
Black diaphragms associated with it are now a thing of the past, says Jumo.
In order to increase the operational life of the electrode, the electrolyte has additionally been provided with solid potassium chloride (KCl) that is finely distributed in the gel.
As a result, the usage of the electrode can be recognised by the electrolyte clearing up.
The Jumo Ag/AgCl conductive system - tried and tested for many years - is used as a reference system.
The solid electrolyte securely encloses the reference system.
Jumo U glass permits operation at temperatures ranging from -5 to +80C.
The electrode withstands pressures in the range up to 6bar.
If requested, a Pt100 or Pt1000 temperature probe can be integrated.
The electrodes can be installed in existing fittings via a Pg13.5 gland.
The new solid-electrolyte electrodes are distinguished by low maintenance and long life.
They ensure that pH measurement in heavily polluted media can now be performed economically.
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