Ionization voltage source

The method of ionizing a gas such as free air to produce a copious supply of ions without the concomitant production of undesirable chemical by-products such as ozone, the time required to produce incipient dielectric breakdown resulting in said by-products being greater than that required to effect ionization of the gas, said method comprising the steps of:

• A applying to an ionization electrode a unipolar voltage having a steady state component which is below the ionization potential of the gas yet serves to stress the gas to render it conducive to subsequent ionization;
• and
• B imposing on said steady state component an ionization component constituted by periodic surges separated by relatively long time intervals, each surge including at least one sharp unipolar pulse having a steep rise time and a fast slew rate, and having a peak amplitude inducing intense ionization of the gas, the pulse duration relative to the incipient breakdown time being insufficient to effect chemical breakdown of the gas.

A voltage source adapted to apply voltage excitation to an electrode in a wave form resulting in the establishment of an intense electrostatic field without, however, producing substantial amounts of undesirable chemical by-products, said gas having a predetermined ionization potential, the time required to produce incipient dielectric breakdown resulting in said by-products being greater than that required to effect ionization of the gas, said source comprising:

• A means to produce a unipolar voltage wave having a steady state direct-current component which is well below said ionization potential;
• and
• B means to impose a pulsatory component on the steady state component in the form of periodic surges which are separated by relatively long intervals, each surge being composed of at least one sharp unipolar pulse having a steep rise time and a fast slew rate and having a high peak amplitude, the duration of the pulse relative to the incipient dielectric breakdown time being insufficient to break down the gas chemically, but the peak amplitude thereof being such as to produce an intense electrostatic field, the steady state component acting to prevent the electric field from collapsing completely in the interval between surges.