Patent GB-190300175-A (GB)
Title: Means for Promoting Electric Discharges Across a Di-electric Gap in a Circuit.
Inventor: WILLIAMS ALFRED
Filed: 1903-01-03
Granted: 1903-12-31
Abstract: 175. Williams, A. Jan. 3. Telegraphs.-Consists in providing di-electric spark-gaps, applicable to Hertzian transmitters, with a high-resistance shunt, whereby vigorous sparking may be obtained from sources the energy of which would otherwise be insufficient to cause sparking, while, with a given source, the length of the spark-gap may be increased, consequently increasing the intensity of the electric radiations. The spherical poles of the spark-gap are carried by screws e, f in insulated supports a, b, Fig. 2, so that the length of gap may be adjusted, whilst the shunt circuit consists of a disc n of talc, bauxite, hµmatite, or other material of high resistance, carried on a screw m in a pivoted insulated support h. There may be gaps between the poles e, f and the disc n, or one or both poles may be in contact with the disc, according to the power of the source of electrical energy. The disc may form the base on which the supports a, b are carried, in which case the supports are effectually insulated from the base, and are also pivoted, so that the poles e, f may be rotated and brought as near the base as desired and then clamped in position by a nut on the pivot. A modification is shown in Fig. 3, in which a block o of high resistance is placed laterally to one pole of the spark-gap and connected by a wire with a pointed screw r adjustable angularly near the other pole. Both the rod r and the block o are longitudinally adjustable. In the case of very high potentials, the pointed screw r may be dispensed with, and the block o replaced by a longitudinally-adjustable base conductor, suitably mounted in an insulating-support. This base conductor may be in the form of a spiral enfolding one pole of the spark-gap, the inner end of the spiral being brought more or less close to the pole. The device is also applicable to coherers for Hertzian waves, to the discharging of vacuum tubes, and to the production of discharges for therapeutic purposes. In the Provisional Specification, the device is stated to be applicable to the regular maintenance of the electric arc for lighting purposes, and to the insuring of ignition sparks in internal-comhustion engines. A modification of the device is also described, in which one end of the shunt resistance is connected with one terminal of the source or anywhere between it and the corresponding spark-gap pole, but preferably near the latter, and the other end brought near the other pole of the spark-gap. The shunt may be attached either to the positive or the negative terminal of the source. Arrangements are provided for adjusting the position and modifying the resistance of the shunt circuit, either at will or automatically, such as by means of a solenoid energized by the passing charge, or by a relay. The shunt may also be provided with subsidiary shunts of a like character and arrangement for rendering the effect more sensitive. The di-electric gap may consist of air, other gases and vapours, an insulating-liquid, or a solid di-electric.