Patent ID: 7179369

Claim:
Oil filter system for cleaning or cleaning and desiccation of the oil in a tap changer at a power transformer or a plunger core coil, wherein a pump unit constructed as a pressure vessel is provided, wherein the pump unit comprises a conveying pump, a pump motor driving the conveying pump and a filter cartridge, and wherein an oil circuit is formed between the pressure vessel and tap changer by a return line for transport to the tap changer of the oil that has flowed through the filter cartridge and a forward line for transport to the filter cartridge of the oil that is to be cleaned, characterised in that a measuring device for detection of the volume flow of the throughflowing oil and conversion into an electrical measurement signal is provided, that the measuring device is connected with a regulator in which a setting signal can be produced as a result of a comparison of the electrical measuring signal with a preset target value, that the regulator is electrically connected with the input of a frequency converter and that the output of the frequency converter is electrically connected with the electrical terminals of the pump motor.