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03.12.01
10:39
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250
pH electrodes/conductivity measuring cells and their applications
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Water analysis technology
Universal electrode, type 01 pH
+ + + 0 – – 0 0 0 0 – – – 0 – – – – – 0 0 0 0 + 0 0 – – 0 – 0 – 0 pH
Lab. electrode, type 02 pH
0 + + 0 – – 0 0 0 + – – 0 0 0 0 0 – 0 + 0 0 + + 0 0 – – 0 0 + 0 0 pH
Universal electrode, type 04 pH
+ + + 0 – – 0 0 0 0 – – – 0 – – 0 – – 0 0 0 + + 0 0 – – 0 – – – 0 pH/°C
Special electrode, type 05 pH
+ + 0 + – 0 + + + + – – 0 + – – 0 – – 0 0 + + + + + + – 0 0 – – 0 pH/°C
Penetration electrode, type 03 pH
0 0 0 0 + + + + + – 0 0 – 0 – + – + + – + – + 0 + + + 0 0 0 – – – pH
Robust penetr. electrode, type 13 pH
0 0 0 0 + + + + + – + + – 0 – + – + + – + – + – + + + + 0 0 – – – pH
Conduct. meas. cell, type 07 mS
+ + + + – + + 0 0 0 – – 0 + – – + – – + + + + + + 0 0 – 0 0 – – + mS/°C
Conduct. meas. cell, type 10 mS
+ + + + – + + 0 0 0 – – 0 + – – + – – + + + + + + 0 0 – 0 0 – – + mS/°C
Key:
+ suitable
0 suitable in certain cases
– not suitable
Example: cooking salt
An exact analysis of the contents in the laboratory will reveal the cause If cooking salt (NaCl) is added to of this alarming increase. Perhaps water the salt then breaks down into sewage was discharged into the its components (ions) Na+ and CI–. lake. Ions are charged particles and are responsible for the electrical Testo conductivity measuring resistance of the water. systems guarantee problemfree conductivity The conductivity provides informeasurement due to: mation on the total number of dissolved, charged components. What is conductivity? – a robust and user-friendly handheld instrument with simulFor electric conductivity electrical If, for example, the conductivity in taneous display of conductivity resistance is measured between two a lake has increased during a (referred to reference temperaelectrodes e.g. in a liquid. specific time the number of ture) and the temperature of the particles dissolved has also product being measured The lower the resistance the higher increased. the conductivity and vice versa. – the adaptability of the measuring Substances such as salt dissolved system to different measuring in water lower the electrical solutions on account of its resistance thus increasing adjustable temperature conductivity. coefficient Analytical instruments are only as accurate as the sensor used to perform the measurements. When measuring pH or conductivity only those probes suited to the particular substance can guarantee an accurate measured value.
– a robust measuring cell with 4 electrode measuring technology to protect from disturbing influences caused by polarisation effects
– fully automatic temperature compensation with the help of a temperature sensor integrated in the measuring cell – the display and documentation of measured and calibrated data
Conductivity measuring cells The 4 electrode measuring technology in our sensors enables an extensive measuring range to be covered with only one measuring cell. It also prevents the measured values becoming distorted by the formation of physical coatings, such as in waste water for example, ensuring accurate results every time. 4 electrode cells do not require replating unlike 2 electrode cells which means they have an almost unlimited lifetime.