a gas outlet conduit 25 on the receiver which conduit carries on from the vacuum pump outlet back to the filter station hood in the receiver oil is separated from the gas the latter being recycled through the outlet 26 of the vacuum pump back to the hood in the filter station while the clear filtrate is conducted by a pump 27 and associated conduit to a clarified or clear oil storage tank 28 clarified oil in the tank 28 is ready for reuse in the cooker new oil as needed to make up for oil lost from the cooker with the cooked food and with the filter cake is conveniently added to the clarified oil storage then to the cooker via a suitable pump 29 and valve 31 so far as system operation is concerned new oil and clarified oil are equivalent except that new oil needs heating while recycled oil may already contain some color bodies for initial precoating of the filter and for adding additional precoat bed materials a separate mix tank 32 is provided into which clear oil is supplied by a valved conduit 33 a suitable precoat pump 34 and conduit 36 are provided to conduct the proper filter material to the filter as needed for precoating and free fatty acid control the rotary drum vacuum filter 20 is of.