Dissolved Oxygen Sensors

Dissolved oxygen (DO) is a liquid process measurement for determining the amount of oxygen dissolved or carried in the process liquid. There are three common technologies for dissolved oxygen measurements: polographic, galvanic and optical. The standard units of measure are milligrams per liter (mg/l), parts per million (ppm), parts per billion (ppb), or % saturation.

  • The DO30G sensor for dissolved oxygen is designed for use in water treatment plants such as sewage treatment works, effluent activated sludge process, and potable water treatment. It is also effective in river monitoring, intake protection, fish farming, and other fields where water quality is important.

  • The rugged design of the OXYFERM's membrane is stable, fast to respond, has low flow dependance, and withstands numerous sterilizations.

  • Dissolved oxygen measurements in the parts per billion range are critical in, but not limited to power generating plants. Maintaining a low level of dissolved oxygen in boiler feedwater assures that corrosion of certain components is minimized. A reliable measurement of ppb dissolved oxygen helps to reduce downtime and improve efficiency.

  • Hamilton's VisiFerm is the first optical sensor ever for the measurement of dissolved oxygen that has significant advantages compared to classical Clark cells because there's no electrolyte needed and the luminophore is embedded in a robust sensor cap. Typical applications are biotechnology, water treatment and monitoring as well as in breweries, wineries and soft drink processing.

  • The VisiTrace optical DO sensor meets crucial needs in industries like power plants and breweries where controlling the dissolved oxygen to low ppb levels is important for maintaining product quality or reducing downtime.

Overview:

We recommend returning your ZR402G to the factory for display replacement.

There are several reasons:

  1. There are 2 generations of displays for the ZR402G: the Green display and the White display. The green displays were used on the early model ZR402Gs and are no longer available. We can replace the entire electronics assembly if a Green display has failed. The white displays are available.
  2. The display assembly is easily damaged by static. You MUST have a good grounding system when you handle the boards.
  3. If the display requires alignment, it has to be returned to the factory. The alignment routine requires special care or the unit can be permanently damaged.

For all of these reasons, we highly recommend coming to the Yokogawa repair center to ensure the display of your ZR402G is correctly replaced.

If you will be replacing the display yourself, we can seel you the display assembly. 

Overview:

How to startup a new sensor, or how to replace the Membrane Cap and Electrolyte.

 

Startup of a new Oxygold G sensor:

The Oxygold G sensor is shipped dry with a protective cap over the end of the Membrane Cartridge.

CAUTION: The electrolyte should not be allowed to touch your skin or clothing. Use Personal Protective Equipment such as gloves and protective eyeware when working with the electrolyte.

 

1. Inspect the new sensor for damage during shipment. 

2. Remove the membrane cartridge and rinse it once with a small amount of the OXYGOLD G electrolyte. 

3. Using the installed pipette dispense 1.5 ml. of the OXYGOLD G electrolyte into the membrane cartridge.

4. Maintain the membrane cartridge in a vertical position to prevent spilling the electrolyte, and insert the sensor shaft and screw it in place. Rinse off any electrolyte that may remain on the exterior of the sensor. 

5. The sensor must now polarize to remove the oxygen that is dissolved in the electrolyte. This can be accomplished by connecting the sensor to a transmitter and turning on the power. It will take 2 hours for the polarization to be completed. Normally the next step will be to perform an air calibration so you should leave the sensor in air during this polarization period. 

6. Perform an air calibration. 

Replacing the membrane cartridge and electrolyte

1. Remove the membrane cartridge and discard any remaining electrolyte. Do not attempt to polish or even wipe the anode and cathode of the sensor. 

2. If the membrane cartridge is being replaced discard the old cartridge and follow the steps below with the new cartridge. If it is being reused, follow the steps below with the old cartridge. 

3. Rinse the membrane cartridge once with a small amount of the OXYGOLD G electrolyte.

4. Using the installed pipette dispense 1.5 ml. of the OXYGOLD G electrolyte into the membrane cartridge.

5. Maintain the membrane cartridge in a vertical position to prevent spilling the electrolyte, and insert the sensor shaft and screw it in place. Rinse off any electrolyte that may remain on the exterior of the sensor. 

6. The sensor must now polarize to remove the oxygen that is dissolved in the electrolyte. This can be accomplished by connecting the sensor to a transmitter and turning on the power. It will take 2 hours for the polarization to be completed. Normally the next step will be to perform an air calibration so you should leave the sensor in air during this polarization period. 

7. Perform an air calibration. 

We also have a video you can watch of the OxyGold G startup process. Click the link at the top of this page.

 

 

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