Bbc Brown, Boveri & Company, Limited

Bbc Brown Boveri Ag

Michael Hirth

Ulrich Kogelschatz

Baldur Eliasson

Peter Erni

Urs Gloor

Jakob J Keller

Helmut Britsch

Tony Kaiser

Hans-Rudolf Beer

Marcel Escudier

Norbert Wiegart

The high-power radiator includes a discharge space (12) bounded by a metal electrode (8), cooled on one side, and a dielectric (9) and filled with a noble gas or gas mixture, both the dielectric (9) and also the other electrode situated on the surface of the dielectric facing away from the discharge space (12) being transparent for the radiation generated by quiet electric discharges. In this manner, a large-area UV radiator with high efficiency is created which can be operated at high electrical power densities of up to 50 kW/m.sup.2 of active electrode surface.

High-power radiator

In the separation and/or reaction of particles, these are heated together with a gaseous carrier medium. Constituents of these particles thus vaporize and form a mixture, while solid constituents remain. A process is to be indicated which enables pollutants adsorbed on the particles to be separated off and/or reacted economically, without an uncontrolled release of residual pollutants to the environment. An apparatus for carrying out the process is also to be provided. This is achieved by mixing the particles and the carrier medium at controlled rates to give a fluidized blend. This blend is heated in a fluidized bed of a heating device in such a way that a mixture is formed. Immediately after the mixture has left the heating device, solid constituents of the mixture are precipitated and the remaining part of the mixture is then passed forward in a closed circulation.

Process for separating and/or reacting particles

The high-power radiator comprises a discharge space (12) bounded by a metal electrode (8), cooled on one side, and a dielectric (9). The discharge space (12) is filled with a noble gas or gas mixture. Both the dielectric (9) and the other electrode situated on the surface of the dielectric (9) facing away from the discharge space (12) are transparent for the radiation generated by quiet electric discharges. In this manner, a large-area UV radiator with high efficiency is created which can be operated at high electrical power densities of up to 50 kW/m.sup.2 of active electrode surface.

Method and device for agglomerating particles of opposite electrical charge suspended in gas streams, in which two partial gas streams (3) are provided, in which the particles are alternatingly charged with positive and negative ions in a manner such that sequences of particle clouds (7, 8) with alternatingly positive and negative charge are generated locally, and that the two partial gas streams (3) are brought together in a manner such that the particle clouds (7, 8) of opposite charge impinge on each other and the particles of different sign conglomerate into larger particles. Two corona discharge devices consisting of a point (5) and plate (6) are fed by two transformers wired in opposite phase.

Method and device for agglomerating electrically nonuniformly charged-up

A method and device for removing solid or liquid particles contained in suspension in a gas stream by an electric field, wherein the gas stream flow is directed past ion sources which simultaneously act as field electrodes. The suspended particles are thereby changed in a bipolar manner, such that approximately half of the particles are positively charged and the other half negatively charged, and are forced by the electric field to migrate across the gas stream into a preferred neutralization zone where they are concentrated, discharged, partially agglomerated and coagulated. Subsequently, the particle-enriched and particle-depleted partial gas stream thus formed are separated and treated further in accordance with operating requirements. Thereby the remaining gas stream maximally loaded with particles is fed into a particle-removal device where their withdrawal occurs. The device results in a considerable reduction in the gas volume carried along up to the fine-cleaning stage, and a decrease in cost of the electrofilter by a factor of two or more.

Process and device for the removal of solid or liquid particles in

A method for electrostatically charging up particles suspended in a gas stream by means of ions originating from a separate unipolar ion source, wherein the ions are injected into the gas/particle stream by means of an alternating field and are deposited on the particles. The frequency of the alternating field is chosen so high at the specified maximum field strength that the drive velocity of the ions during a half-cycle is insufficient to carry the ions to the counter-electrode. As a result, undesirable wall recombination of the ions is avoided.

Method for electrostatically charging up solid or liquid particles

In an internally cooled tubular ozonizer, there is built into the interior of the glass tube (5) a cooling tube (9) whose outer diameter is only slightly smaller than the inner diameter of the glass tube (5). The annular gap left is filled up with a temperature-resistant casting compound (10) which conducts heat well. In the case of a synthetic resin casting compound (10), the cooling tube (9) is connected galvanically via contact springs (11) to the metal layer (8), serving as the inner electrode, on the inner wall of the glass tube (5). The heat transfer from the cooling agent in the cooling tube (8) to the glass tube (5) is not impeded by the casting compound (10). Temperature stresses between the glass tube (5) and the cooling tube (9) are largely reduced, as a result of which the operational safety of the ozonizer is increased, especially at fairly high power densities.

Tubular ozonizer with cooled inner electrode

In modern ozone generators, high power densities are achievable when dielectrics (3) based on ceramics or filled plastic dielectrics and corresponding gap widths and dual cooling are used. With respect to efficiency, such ozone generators are inferior to those with a glass dielectric. To improve the efficiency and the resistance to the discharge attack, it is proposed to glaze the titanium oxide ceramic on the surface and to coat the plastic dielectrics with a high-temperature ceramic adhesive based on SiO.sub.2.

Ozone generator

Through modular construction of the ozone generator from block modules (1) of metal which have through holes (2) as outer electrodes and can be directly cooled, the required mechanical tolerances can be maintained. In particular, if the high voltage electrode (8) and the dielectric (11) is cooled, high power densities can be achieved.

High-power ozonizer

In modern ozone generators high power densities can be achieved using ceramic-based dielectrics and suitable gap widths and double cooling. By constructing the dielectric layer from dielectric powders of different grain size and binding with artificial resin, the long-term breakdown voltage of the dielectric layer can be increased to such an extent that they fulfil the operating requirements.

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Unterentfelden, Switzerland

Michael Hirth