Electrostatic spraying

Portable electrostatic spraying apparatus including

• (a) a spray nozzle,
• (b) means to supply liquid to be sprayed to said spray nozzle,
• (c) a low voltage power source,
• (d) a high voltage generator powered by said low voltage power source, whereby rectified high voltage pulses may be produced across its output,
• (e) a capacitor connected to said nozzle and to one side of said generator output, whereby said capacitor may be charged by said rectified high voltage pulses so that said nozzle may be maintained at a sufficiently high potential, with respect to the other side of said generator output, to cause electrostatic atomisation of said liquid at said nozzle,
• characterised in that capacitor has a value below ##EQU4## where V is the average voltage, expressed in kilovolts, that said generator is capable of maintaining at said nozzle, and in that said capacitor is formed by the capacitance between a lead connecting said one side of the generator output to said nozzle and a lead connected to said other side of the generator output,
• said generator being capable of producing said high voltage pulses of such magnitude and frequency that the potential at said nozzle may be maintained at a sufficient value to cause electrostatic atomisation of the liquid but without corona discharge.