This invention relates to an improved heat generating device of the type utilizing a liquid such as oil as the heat transfer medium and more particularly to improved apparatus for heating the oil by friction, for absorbing the created heat and distributing it to a point of use. 
Heat generating devices using air or oil as the heat transfer medium are well known and examples may be found in such patents as U.S. Pat.  Nos.  2,625,929, 3,481,322, 3,791,167 and 3,813,036.  The present invention discloses improvements over such devices in efficiency and economy and with considerably less complicated and sophisticated construction. 
In general, the present invention comprises a sealed drum of heat conducting material containing a relatively small amount of oil and an internal cage-like agitator rotatable in closely spaced relationship to the inner wall of the drum.  Rotation of the agitator acts to drive the oil through restricted passageways therein against the drum whereby the oil is heated by friction and the heat is absorbed and radiated by the drum from which it is preferably moved by a blower means to any desired point of use. 
Accordingly, the important objects of this invention are to provide a heat generating device of the type characterized which is simple in construction, economical to manufacture and operate, highly efficient and safe in use, environmentally clean and generally improved over similar type devices previously known. 
More particularly, one of the objects of this invention in a heat generating device of the above class is to provide a new and improved agitator means for generating heat from the oil heat transfer medium. 
A further object is to provide a heat generator as characterized in which the oil does not foam. 
Still another object herein is to provide a heat generator of the above class particularly adaptable for residential and industrial furnaces as well as other uses including water heaters and the like. 
The foregoing objects and such further objects as may appear herein, or be hereinafter pointed out, together with the advantages of this invention will be more fully discussed and developed in the more detailed description of the accompanying drawings.