To Consort website  |  Print page

User Tools

Site Tools


do_measurementprinciple

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
do_measurementprinciple [31/03/2015 13:34]
pieter [Temperature effects on the probe output]
do_measurementprinciple [31/03/2015 13:35]
pieter [Galvanic probe]
Line 2: Line 2:
 The dissolved Oxygen electrode is a galvanic MPOD (Membrane-covered Polarographic Oxygen Detector) system. ​ They provide a convenient approach to an essential direct measurement of molecular oxygen. The membrane isolates the electrode from the sample and the oxygen is detected as it diffuses across the membrane. The probe can be used to measure any system where oxygen is present. Calibration of the sensor is readily achieved if the oxygen concentration or solubility at a specific condition is known. The dissolved Oxygen electrode is a galvanic MPOD (Membrane-covered Polarographic Oxygen Detector) system. ​ They provide a convenient approach to an essential direct measurement of molecular oxygen. The membrane isolates the electrode from the sample and the oxygen is detected as it diffuses across the membrane. The probe can be used to measure any system where oxygen is present. Calibration of the sensor is readily achieved if the oxygen concentration or solubility at a specific condition is known.
  
-=====Measurement ​probe=====+=====Galvanic ​probe=====
 A galvanic MPOD consists internally of two metals of different nobility which serve as electrodes. The more noble metal is the cathode (Silver, Platinum or Gold), the other (Lead or Zinc) is the anode. In the presence of an electrolyte,​ a voltage around 800 mV is produced between the two metals. ​ A galvanic MPOD consists internally of two metals of different nobility which serve as electrodes. The more noble metal is the cathode (Silver, Platinum or Gold), the other (Lead or Zinc) is the anode. In the presence of an electrolyte,​ a voltage around 800 mV is produced between the two metals. ​
  
 Molecules of oxygen dissolved in the electrolyte will diffuse to the surface of the cathode and pick up electrons which, in combination with water, will produce hydroxyl ions. At essentially the same time, hydroxyl ions will give up electrons at the anode and form an oxide. The resulting transfer of electrons establishes a current flow through an internal resistance which is measured as a voltage by the oxygen meter. Molecules of oxygen dissolved in the electrolyte will diffuse to the surface of the cathode and pick up electrons which, in combination with water, will produce hydroxyl ions. At essentially the same time, hydroxyl ions will give up electrons at the anode and form an oxide. The resulting transfer of electrons establishes a current flow through an internal resistance which is measured as a voltage by the oxygen meter.
  
-The membraned ​oxygen electrode offers the following advantages:+The membrane ​oxygen electrode offers the following advantages:
  
   * The membrane encloses the two electrodes in a captured volume of electrolyte,​ ensuring constant electrolyte strength and purity so that ions which might otherwise “poison” the probe are not present.   * The membrane encloses the two electrodes in a captured volume of electrolyte,​ ensuring constant electrolyte strength and purity so that ions which might otherwise “poison” the probe are not present.
do_measurementprinciple.txt · Last modified: 31/03/2015 13:35 by pieter