A liquid heating device, comprising a pump for pumping a liquid, a convertor for converting of a flow of the liquid, heat exchange a unit, the convertor being formed as a cyclone connected with the pump and having a main spiral passage for a tangential supply of the liquid, passage a unit from withdrawal of the liquid, and an additional spiral passage which is directed toward a side which is opposite toward the main passage is directed, the spiral passages having outlets which are offset relative to one another along an axis of the cyclone.

A viscous fluid type heat generator adopted for being incorporated in a heating system of an automobile has a generally cylindrical hollow housing assembly in which a rotor element in the shape of an axially elongated hollow cylindrical element is rotatably received by being supported on a rotating drive shaft. The elongated rotor element has an outer circumference and end faces to cooperate with an inner wall of the housing assembly to define a heat generating chamber filled with viscous fluid, and a spiral heat receiving chamber hermetically separated from the heat generating chamber and permitting heat exchanging liquid to spirally flow therein to thereby receive heat from the heat generating chamber. The outer circumference of the elongated rotor element has a radius R and an axial length L designed so as to have such a relationship that L is larger than R.

An inline heating device for fluid has rotary members frictionally engaging fixed housing extensions on a central fluid transfer conduit. The rotary members are rotated by drive shafts having multiple vein turbine assemblies respectively thereon within the fluid transfer conduit. The rotary members have enhanced friction engagement surface which are spring urged against the fixed housing extension engagement surfaces generating heat therein for thermal transfer to the fluid flow within the transfer conduit driving the turbine assemblies.

A viscous fluid heater has a heating chamber and a radiator chamber defined in a housing and transfers heat generated by shearing viscous fluid in the heating chamber with a rotor to circulating fluid in the radiator chamber. The housing includes outer and inner housing parts, which are secured to each other. An inner wall surface is formed on the outer housing part, and an outer wall is formed on the inner housing part. The radiator chamber is defined between the inner wall and the outer wall to conduct the circulating fluid through the radiator chamber.

An apparatus for heating a liquid comprising a housing having an internal chamber and a rotor disposed in said chamber. A drive shaft rotatably supported in the housing and extending into said chamber for imparting mechanical energy to the rotor. The rotor having a generally hemi-spherically shaped form and provided with a series of openings. A fluid intake passage in said housing preferably arranged to be nearer the rotational axis of the rotor and a fluid exit passage preferably positioned radially outwardly of said rotor.