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KONDIC Oil Filtration

TRANSFORMER OIL FILTERING UNIT - S 4000 vario - KONDIC Oil Filtration - 1
TRANSFORMER OIL FILTERING UNIT - S 4000 vario - KONDIC Oil Filtration - 2
TRANSFORMER OIL FILTERING UNIT - S 4000 vario - KONDIC Oil Filtration - 1
TRANSFORMER OIL FILTERING UNIT - S 4000 vario - KONDIC Oil Filtration - 2


Adjustable oil flow rate 1200 - 4000 l/h
Maximal oil flow rate 4000 l/h
Heating capacity 60 kW (2 x 30 kW)
Adjustable oil temperature range 0 °C – 90 °C
Differential temperature (inlet/outlet) approx. 28 °C
Minimal oil inlet temperature 5°C
Vacuum pump capacity 100 m3/h
Filter fineness 3 microns
Total power 65 kW
Final oil qualities, after three passes:
- water content 2 - 5 ppm
- gas content 0.05 % Vol
Operating pressure in degassing tank 2 - 9 mbar
Unit, size 2000x1200x2000 mm
Unit, weight approx. 800 kg

Above mentioned values after conditioning are guaranteed when treating naphtenic based mineral oils with
normal foaming conditions

The Unit is delivered ready for operation, together with:
- control panel, wiring, two connecting hoses for oil (each 10 m long) and safety devices which provides maximum
operating security;
- frequency converter for adjustment of flow rate from 30% to 100% of the capacity of the gear pump and digital
flow meter
- specially designed system in the degassing tank which provides uniform distribution of the processed oil in the
low-pressure environment, in order to achieve best treatment results;
- spare filter cartridge with 3 micron fineness;
- spare heating element;

The Unit S4000 Vario is designed for filtering, drying and degassing of transformer oil. The model and the
example that were kept in mind during development and construction of this Unit were the units, which
proved to be most efficient in operation, built by leading European manufacturers. All essential parts of the Unit
(vacuum pump, gear pump, electromagnetic valve and floater) are produced by leading German manufacturers.
Some of the components (such as fine and coarse filters, temperature control, construction of the heaters, gear
pump) had to be modified to improve the operation of the Unit and to eliminate shortcomings noticed in the
operation of some other unites of this kind.

The electrical properties of insulating oil (such as puncture voltage and coefficient of losses) can be considerably
improved by its filtering, degassing and dehydration. Only properly and sufficiently filtered and dried oil is suitable
for filling up of the transformer. Even brand-new oil is rarely clean enough to be used in high-voltage installations,
as it is often already polluted in the transporting barrels and it may absorb too much moisture in contact with air.
During its operation, transformer-insulating oil is absorbing moisture over its free surface in the expansion vessel
and it becomes polluted by absorbing dirty particles, fibers, soot and aging products. Therefore, oil conditioning
has to eliminate the following:
- solid particles
- free and dissolved water
- dissolved gasses
The puncture voltage can be considerably increased and the coefficient of loses tangδ improved by filtering,
degassing and dehydration of insulating oil to the extent depending on moisture content.

1. Inlet valve a spherical valve 6/4“ with special “Teflon” gaskets
2. Coarse filter as oil is often very polluted, the Unit is fitted with a large sized, easy to open and clean, coarse
filter. Oil is conveyed at a reduced flow rate around a strong permanent magnet which retains steel particles and
protects the gear pump from damages 2a. Service valve a spherical valve 1“ with special “Teflon” gaskets
for maintenance and cleaning of coarse filter
3. Oil heater 60 kW power of the heater is divided into two stages, each of 30 kW. Oil is heated indirectly by means
of electric heating elements insulated from oil by pipes and air. The heating process is thereby gradually
accomplished and, with the sufficiently large heating surface, any damage of oil is excluded. Together with the
thermal control (details of which are given in the following text) this allows heating of oil in individual stages, e.g.
at higher temperatures quite “tenderly”. Special electrical connection prevents the heater to be turned on if the
gear pump is not operating. This is to protect the non-circulating oil from overheating
4. Safety valve prevents increase of pressure in case oil is overheated
5. Safety thermostat the Unit is equipped with a precise thermostat, acting as a safety thermostat. By means of
other (control) thermostat, both heating stages can be controlled. This safety thermostat is designed to allow max.
temperature of 900°C, with a construction that allows it both safety and control role.
6. Control thermostat Is fitted onto the same housing with safety thermostat. It has an external button for the
temperature range from 0°C up to 900°C; the button maximum position is 900°C, thus these control thermostat act
as another safety device to prevent oil overheating. Both heating stages are adjusted with this thermostat. The
swithching on of the second heating stage is delayed via time-relay (that can be adjusted) in order to avoid
sudden electric overload. Control thermostat should be adjusted to cca. 60-65 °C which represents an optimal
temperature for oil processing
7. Thermometer measures the temperature at the outlet of the oil heater
8. Degassing tank of a welded construction, with specially shaped separating sheets for equal distribution of oil.
Oil is conveyed over the “RASIG” rings, where oil surface is significantly increased and gas fractions can be
efficiently separated. In addition, the resting time of oil is increased tothe maximum. The degassing tank is
equipped with a sight-glass for the visual control of the process, as well as with a special lamp for illumination of
the tank interior. The power supply of the lamp is 12 V for safety reasons
9. Floater this floater, as essential control equipment, is procured from well-known European manufacturer. It
protects the degassing tank from overfilling and, together with electromagnetic valve, prevents the insulating oil
to penetrate into the vacuum pump
10. Electromagnetic valve a special magnetic valve capable of operating in vacuum, resistant to transformer oil
and high temperatures. Together with the floater, it controls the oil level in degassing tank
11. Gear pump with maximum of 4000 l/h capacity. The capacity of the oil flow can be adjusted via frequency
regulator installed at the control panel. Adjustable capacity is from 1200 – 4000l/h. This pump is specially
designed to operate under vacuum conditions
12. Overflow valve protects the Unit from an excessive rise of pressure in case outlet valve is negligently closed or
because of some other reason
13. Air valve a spherical valve installed on the fine filter container for elimination of trapped air from the filter
14. Fine filter container the fine filter container is of a size that allows it to accept a standard filter separating
particles of 3 microns
15. Mano-vacuummeter for reading of fine filter dirtiness, through oil pressure rise. Filter should be cleaned when
the pressure rises up to 2.5 bar
16. Sampling valve a spherical, closing valve for insulating oi sampling
17. Outlet valve a spherical 6/4” valve with special “Teflon” gaskets
18. Air valve a spherical valve for aeration of the degassing tank in case of an excessive foaming of oil
19. Sight-glass for process control equipped with search-light fitted on its left side to illuminate the interior of the
degassing tank
20. Vacuum meter measures vacuum in the degassing tank and/or in the transformer
21. Separator of a special construction for separation of liquid fractions from gasses which are extracted out of
degassing tank. It is equipped with sight-glass for control of separated water
22. Discharge valve a spherical valve for discharging condensate from the separator
23. Vacuum pump of 100 m3/h capacity, provides vacuum for operation of the Unit. It is equipped with a socalled
“gas-ballast” valve. Maximal vacuum that could be achieved with this pump is 0.1 mbar
24. Drainage valve a spherical valve for drainage of transformer oil from oil heater
25. Control panel it consists of frequency converter, fuses, contactors, electric motors electrical protection,
protection relays, transformer, main switch, internal wiring etc., for an automatic operation of the Unit. Control
panel is equipped with totalstop taster for immediate shut down of the complete Unit in urgent situations. In
addition on the front of control panel, there are three green indicator lights (L1, L2 and L3) for voltage presence.
Beside this, above every cam switch, there is also an green light, that serves as an indicator of the current state
(on / off) of the respective components.
26. Check valve a valve, which allows transformer oil to flow through it in only one direction, and prevents its
returning into the Unit
27. Framework a welded, sectional steel construction, which represents foundation for all described components
of the Unit
28. Electric equipment consisting of driving motors for the gear and vacuum pump and of internal wiring of the
Unit. Suitable for three-phase, 50 Hz power supply

29. Two flexible hoses suction (6/4”) and discharge (6/4”) hoses are specially designed, suitable for operation
under vacuum and with oil. Each hose is 10 m long
30. Oil tub oil retaining tub in case of oil leakage. It is placed under the complete Unit with a purpose of preventing
environmental accidents and spillage of oil into the surroundings.
31. Rollers for base frame comprising of 4 swivelling rollers, 2 of which are equipped with locking device
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