The Electricity Council

Electricity Association Technology Limited

David Preston Simpson

Robert Stirling

James Lawton

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. In use, a current passes perpendicular to the flow of the fluid, but the electric potential on the axis is near to neutral, and hence the leakage current from the ohmic heater is substantially reduced.

OHMIC heater including electrodes arranged along a flow axis to reduce

An apparatus for heating an electrically conductive fluid ohmically by passing an electric current through the fluid between electrodes spaced along a pipe through which the fluid flows. The pipe has an electrically insulating internal liner and is cooled, e.g. by cooling water flowing through a cooling jacket between inner and outer skins of the pipe. The inner skin supports the liner and is perforated to allow intimate cooling of the liner. The cooling prevents heating of the fluid in a layer immediately adjacent the internal liner to such a temperature that the medium would foul the liner.

Apparatus for heating electrically conductive flowable media

A heater for liquid foodstuffs has a pipe through which the foodstuff flows and electrodes spaced along the pipe to drive a heating current through the foodstuff. In the embodiment, the electrode is a platinum coated cylinder arranged transversely in an enlarged part of the pipe so that electric current flows to the electrode only over a smooth surface portion, entirely within the edges of the exposed electrode surface.

A method of disrupting vapor films formed in film boiling in boilers, in which method transient electrical discharges are effected either in the boiler liquid or in a body of liquid in acoustic communication with the boiler liquid. The electrical discharges are effected at one or more selected locations in the boiler to produce shock waves which act on surfaces of the boiler liquid space where vapor films are to be disrupted. By disrupting such vapor films there is enabled an improvement in the heat transfer rates per unit area across the interface between the fire space and the liquid space of a boiler. There are also disclosed various arrangements in boilers for generating these shock waves. Electrical discharges may be effected between a pair of electrodes mounted in the boiler or between an electrode and an adjacent wall of the boiler, and several mounting configurations for electrodes in boilers are described.

Boilers

The contact area between a first phase of a multi-phase system and a liquid second phase of the system is increased by effecting transient electrical discharges between electrodes immersed in the liquid second phase or in a volume of liquid in acoustic communication with the liquid second phase. The first phase can be in the form of a particulate solid, a gas, or a liquid of lower density than that of the second phase. The first phase is mingled with the second phase by a bubbling technique where the first phase has a lower density than the second phase. The hydraulic shock waves produced by the electrical discharges disperse the bubbles or particles of the first phase in the liquid second phase and thus increase the contact area between the phases. When the electrodes are immersed in a volume of liquid separate from but in acoustic communication with said liquid second phase, these liquids are separated by means of an acoustically transmissive membrane formed from a thin film of stainless steel or from rubber selected such that the product of density (.rho.) and velocity of propagation of sound waves (c) is matched to those of the liquids separated by the membrane. The spacing between the electrodes is adjusted in response to a sensed parameter of the electrical discharges such as to maintain the sensed parameter constant.

Method and apparatus for increasing contact area in a multi-phase system

A method of producing U.V. radiation by effecting an electrical discharge such that at least a part of the discharge path is submerged in water. An apparatus for performing the above method comprises two electrodes spaced apart to form a discharge region, a discharge chamber containing the discharge region, means arranged to apply a high voltage across the electrodes, and means arranged to supply water to the discharge region such that at least a part of the electrical discharge is submerged in the water, at least a portion of the discharge chamber being transparent to U.V. radiation. Also, a method of treating a material comprising producing U.V. radiation as described above in a discharge chamber at least a portion of which is U.V. transparent, passing the material through a treatment chamber adjacent the transparent portion of the discharge chamber; and an apparatus for performing the method of treating a material. In some described embodiments the position of an electrode is adjusted in dependence upon the electrical characteristics of the discharge such as to maintain predetermined conditions. In one embodiment an electrode is mounted in the bottom of the discharge chamber which forms the other electrode; water covers the electrode and has a controlled circulatory motion such as to control the height of water over the electrode and thus the submerged discharge path. In another embodiment one of the electrodes is formed by a layer of mercury; an initiating discharge between a third electrode and the mercury or the other electrode to establish a degree of ionisation of the mercury in the vicinity of the discharge region. The main discharge excites the mercury vapour resulting in radiation at 254 nm.

Growing community of inventors

Chester, United Kingdom

David Preston Simpson