Nordson Corporation

John A Hendricks

Donald R Hastings

Gerald W Crum

Jeffrey A Perkins

Jeffery Edward Dailidas

An improved power supply for an electrostatic spray gun device having a voltage multiplier circuit adjusts to variations in the output load conditions of the multiplier circuit and dynamically modifies the operational loadline of the multiplier circuit in order to maintain optimal operating conditions for the spray gun device notwithstanding output load variations. The power supply utilizes a loadline manipulation circuit coupled to a feedback circuit that monitors the output load, and the manipulation circuit, in response to a feedback signal from the feedback circuit that is proportional to the output load, varies the input voltage level to the multiplier circuit to modify the loadline of the power supply in response to varying load conditions. The manipulator means of the power supply has memory means to store a variety of external commands which will control the manipulation means and a user interface to enter the external commands into the memory. The power supply also comprises a voltage limiting circuit coupled to the output of the multiplier circuit which regulates the output voltage level of the multiplier circuit so that when the output load current increases above a predetermined maximum level the output voltage is reduced to reduce the high voltage stress on the multiplier circuit and high voltage circuitry and reduce the amount of insulation that must surround the multiplier circuit and high voltage circuitry of the power supply in order to insulate it from ground potential.

Spray gun device with dynamic loadline manipulation power supply

A method and apparatus for spraying liquid coating material containing supercritical fluid or liquified gas as a diluent comprises a spray gun having internal passages which transmit the liquid coating material under high pressure from an inlet to a nozzle at the tip of the gun and then to an outlet so that the liquid coating material can be continuously recirculated. A relatively short flow discharge path is formed between the internal passages in the spray gun and the nozzle to avoid the formation of an area of ambient or reduced pressure so that the supercritical fluid or liquified gas is substantially maintained in solution in the liquid coating until it is discharged from the gun. A pressure regulator is provided to maintain a substantially constant pressure drop across the inlet and outlet of the gun to induce flow of liquid coating material through the gun, and to permit several guns to be connected in series without creating a substantial pressure drop therebetween.

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Vickery, OH, United States of America

John A Hendricks