The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 26, 1989
Filed:
Aug. 11, 1988
Geoffrey Wilson, Chesterfield, GB;
Gareth A Evans, Sheffield, GB;
Sarclad International Limited, Derbyshire, GB;
Abstract
An electrical discharge apparatus comprises a plurality of electrodes mounted on an electrode carrier and spaced from a workpiece surface to define a gap across which a train of electrical pulses are transmitted. Dielectric fluid is present within the gap and controlled additions of solid particles are made to the dielectric fluid, with the particles being of a material of different electrical conductivity and/or permittivity to that or those of the dielectric fluid. The concentration by volume of the particles within the dielectric fluid lies within the range 0.05% to 7.0% and the size of the majority of the added particles is in excess of 7 microns. The particles are of a material having a relatively high electrical conductivity, e.g., graphite or metallic particles. Alternatively, the particles are formed from a material having good electrical insulating properties, e.g., glass, ceramic or certain metallic oxides.