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Velcon Superdri Cartridges SD Series

Remove Dissolved Water from Transformer Oil

Reduce Moisture in Transformer Oil to <10 ppm Without Heat & Vacuum


Dissolved water removal from insulating oil is now possible without the need for heat and vacuum oil processing systems. Specifically developed for dehydrating oil to be used in transformers, patented* Superdri® cartridges can help utilities reduce expenses and increase efficiency when processing oil.



  • Unique Construction – Specifically designed for transformer oil dehydration.
  • High Capacity – Process up to 5,000 gallons of oil or more with a single cartridge.
  • Efficient – Single pass water removal to less than 10 ppm total water, or better.
  • Versatile – Models available to fit most industry standard housings.
  • Safe – Will not remove oxidation inhibitors.
  • Cost Effective – Process transformer oil for less than 5¢ per gallon.


Special Considerations

Superdri cartridges are not designed for particulate solids removal. Prefiltering through Velcon 1/2 micron cartridges is recommended if particle contamination is suspected. Superdri cartridges are not recommended for cost effective removal of free water in insulating oil. If free water is suspected, the oil should be prefiltered using Velcon Aquacon® cartridges.



Superdri cartridges are designed for oil processing situations where dissolved water in insulating oil is a concern, and its removal is desirable.

Examples of these situations follow:

  • New distribution and EHV transformers are typically oil-filled under vacuum. If the insulating oil has a high total water content, it is also processed through a heat and vacuum system. Superdri cartridges can be used instead of heat and vacuum to dry the oil.
  • Repaired transformers are often oil filled under vacuum. Flowing the oil through Superdri cartridges eliminates the need to vacuum process the oil.
  • Insulating oil in storage tanks, and tankers of oil that have accumulated a high level of dissolved water can be recirculated and dried to less than 10 ppm total water using Superdri cartridges.
  • Use Superdri cartridges for processing oil in other high voltage apparatus that is sensitive to dissolved water.
  • Use Superdri cartridges to help meet processing specifications where dissolved water sensitive dielectric breakdown voltage test ASTM D-1816 is used, or required.


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