| Oxygen Probe Manual  |  pdf Leaflet  | buy or view price

The most Robust Accurate  and Low Cost probe available

 The Dryden oxygen probe is a very high performance and extremely robust  oxygen probe manufactured by Dryden Aqua  for the measurement of oxygen in water and air. The probe provides for a low cost, easy maintenance sensor suitable for connection to Dryden Aqua monitors, or your own instrumentation.

The probe has a high mv out-put for PLC based controllers, the high out-put increases accuracy and reduces electrical noise problems. The unique shape provides a stream-lined approach and minimizes water turbulence

Typical Applications

• Aquaculture
• Rivers and lakes
• Sewerage effluent
• Industrial waste water treatment systems
• Hydroponics
• Almost any application where you need to measure  the oxygen content of a liquid
• Air quality monitoring, environmental warehouses

Technical Properties

The oxygen  probe is a galvanic cell, basically the probe acts like a battery in which there are two dissimilar metals in a conducting electrolyte solution. The anode is zinc and the cathode is silver, oxidation takes place on the surface of the anode to form a white deposit of zinc oxide. The rate of oxidation is a function of the diffusion of oxygen through a semi permeable Teflon membrane, which is in turn directly related to the partial pressure of oxygen in solution, or in the air. A potential difference is established in the probe, the milli volt out-put being approx. 8mv per 1 mg/l of dissolved oxygen. This gives the probe a reading of approximately 80mv when in air.

Any length of good quality two core  (0.5mm squ, multi-strand) cable can be connected to the probe,  technically there is no limit to the length of cable that you can attach,  however we have only tested to 2000 meters. General maintenance is also very easy,  all that you need to do is keep the probe membrane reasonably clean,   this is achieved by giving the membrane a wipe with a cloth once a week.

Membranes

There are two types of membrane available for our Oxygen probe. The standard is a Teflon membrane which is temperature compensated in the probe to give very accurate measurements of oxygen in ppm or mg/l. The second type of membrane is made from Polythene and is designed for use with our probe when measuring oxygen in percentage saturation % sat.  The Teflon membrane is slightly better than the polythene membrane and mg/l oxygen measurement are more meaningful than % saturation membranes so we always include Teflon membranes as standard unless requested to provide polythene membranes for % saturation.    If you only plan to use % saturation as a measurement then only order the polythene membranes.

How to identify the membranes

Teflon membranes will sink when placed in freshwater, Polythene membranes will float.  If you use the wrong membrane the temperature compensation will not work properly, especially if the water temperature is very different from the air temperature.