Abstract: An ohmic heater comprises at least two electrodes contained within a vessel such that the electrodes lie along the length of the vessel. The vessel has inlet and outlet ports in the top and bottom through which a fluid to be heated flows, passing through the vessel along the length of the vessel. The electrodes are equally spaced about the axis of the vessel and when in use, are each connected to a single phase of a power supply, such that the total voltage at any point in time at the electrodes is near or at a neutral potential of the electric power supply. Electrically conductive guard rings are positioned around the inner periphery of the inlet and outlet ports of the vessel and are connected to the neutral potential of the electric power supply by electrical connectors. A leakage current monitor is interposed between guard rings and the neutral potential to enable current leakage from said heater to be monitored.

Abstract: An induction heater for heating a material is described which has an alternating current carrying conductor 30 extending along an axis of rotation. Mounted about the axis are containers 32 which rotate about the axis and hold the material to be heated. A core 34 is provided encircling the alternating current carrying conductor 30. The core 34 guides the magnetic flux resulting from an alternating current flowing in the conductor 30 to induce a current in the inner sleeve 38 between the conductor 30 and core 34. Current flowing in the inner sleeve 38 is conducted to end plates 40 and 42 and through the containers 32. The containers 32 are heated by the electrical current induced by the magnetic flux in the core 34.

Abstract: An ohmic heating apparatus for heating flowable media which is flowing through a conduit comprises electrodes exposed to the flowing media and supply means connected to the electrodes and to the media to pass a heating current through the flowable media. The electrodes are made of a material of closed microporosity having a resistance to surface fouling. The material of closed microporosity is preferably made of vitreous carbon.

Abstract: A feeder tube (26) for outputting a liquid evenly along its length is formed of an inner tube (40) and an outer tube (42), each having a split (48,50) along at least part of their lengths. The splits (48,50) are positioned away from each other thus allowing liquid in the inner and outer tubes (40,42) through the split (48) in the inner tube (40) and into a gap (44) between the inner and outer tubes (40,42). The liquid is then output from the feeder tube (26) through the split (50) in the outer tuber (42). The feeder tube (26) is incorporated in apparatus for enabling heat transfer between a fluid and an elongate element (22). In the apparatus at least one feeder tube (26) is positioned above and at least in part parallel to the elongate element (22), whereby an even film of the fluid in liquid form is formed on at least a part of the elongate element (22).

Abstract: A heated rotor is provided to heat and circulate a substance comprising a shaft and at least one electrically heated rotor member supported on the shaft. The rotor member comprises an outer electrically conductive casing and at least one inner electrical conductor, electrically insulated from the casing. The or each inner conductor is electrically connected to the outer electrically conductive casing at an unsupported extremity of the rotor member. The shaft provides separate electrical connections to the or each inner conductor and the casing to enable an electric heating current to flow in the inner conductor between the or each unsupported blade extremity and the shaft.