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TF9 540l/h Oil filter

Transorfilter Sweden performs reconditioning of transformer oil through heating, particle filtration and degassing. The oil is heated to about 70°C and through patented technology it is effectively treated and its insulating properties improved.

Reconditioning the oil is a much more environmentally friendly alternative than replacing the oil with new. In addition, brand new oil from the factory must also be degassed (dried) before it can be used in a power transformer.

Our smallest products in the TF-series is TF9-1 which is best suited for smaller transformers eg. in the railway industry, locomotives etc. For handling larger oil volumes, we would rather recommend a higher capacity filter to save time.



Product Description

Transformer oil filter TF9-1 for degassing transformer oil.

The filter is tested before delivery, CE-marked and filled with Nynäs Nytro 10XN transformer oil.

  • Degassing capacity: 9 l/min (540 l/h)
  • Single stage filter (-1) with 1 pcs degassing chamber
  • Operating pressure: <5 mbar
  • Heating power: 18 kW
  • Temperature increase/passing: approx. 40°C
  • Lamellvakuumpump: 1 st á 25 m3/h
  • Roots vacuum pump: No
  • Built-in compressor for backflushing: No
  • Digital flowmeter: No
  • Vacuum instrument: Digital with Pirani gauge
  • Filter housing with 1 pcs filter cartridge (not backflushable)
  • Oil pumps: 2 pcs magnetic coupled screw pumps

Mobile / Stationary

The TF-series transformer oil filter units are manufactured with a welded, painted steel frame. The frame is adapted as a mobile or stationary unit. The TF-series units are available as a mobile unit on a trailers, for transportation on public road, mobile unit with simple wheels for mobility on site or as a stationary unit mounted in a container.

Filtration and heating

An oil pre-heater with heating elements heats the oil and a filter vessel filters away particles. The heating elements are divided into a single thermostatically controlled heating group and are automatically adjusted to the set temperature. The heating group have high capacity and a large heating area with a surface effect of 1.6 Watt/cm².

Extra pre-heaters (A) can be integrated into the larger high-flow equipment and / or equipment used at colder temperatures.

Particle filtration is done with a filter housing containing a filter cartridge. The filter cartridge filters particles down to 1-3 microns. When the back pressure in the filter housing becomes too high due to a lot of sediment and particles the operator will get a visual signal, and it's time to replace the filter cartridge. If filter change is not done, the filter cartridge will go into by-pass mode as the presssure increases even more over time and the oil will pass unfiltered. The life span of the filter cartridge depends on the customer's operating conditions. If only new and clean oil is filtered the cartridge will lasts for a long time.

Filtration according to SAE ARP4205, CST rating 08/04/01.


Patented degassing principle with an even flow of oil over specially developed degassing plates. This process results in controlled and highly efficient degassing. Available as two variants, single stage degassing in one vessel or double stage degassing in two vessels.

Single stage degassing -1

Degassing in one stage with rotary vane vacuum pump. At one pass-through, the amount of water in the oil is reduced to <5 ppm and residual gas value to <0.2% (at start value: <50ppm, 10%). Can be supplemented with roots vacuum pump for process optimization.

Double stage degassing -2

Degassing in two stages with more efficient high degassing in the second stage. A rotary vane vacuum pump is working towards the first and second stages and a roots pump working towards the second stage. At one pass-through, the amount of water in the oil is reduced to <5 ppm and residual gas value to <0.1% (at start value: <50ppm, 10%).


Standard equipment included in the TF-series transformer oil filter is:

  • Inlet hose L=10m incl. lockable camlock connections
  • Outlet hose L=10m incl. lockable camlock connections
  • Integrated air compressor for backflushing of filter elements (Not included in TF18-1 requiring external compressed air connection)
  • Suction nozzle for oil filling (Use with barrel or IBC)
  • Oil sample connections with ball valve and sample hose


Additional information

Weight1250 kg
Dimensions290 × 180 × 222 cm