Abstract:
The present invention relates to a spark discharge generator. The spark discharge system of the present invention includes a plurality of columnar electrodes and a ground plate having a plurality of outlet holes at positions corresponding to the columnar electrodes. The use of the spark discharge generator enables the production of a three-dimensionally shaped nanostructure array on a large area in a uniform and rapid manner.
Abstract:
A high voltage controller configured to drive a high voltage generator. The high voltage controller includes a voltage select input and a current select input, an actual voltage input and an actual current input. First circuitry is configured to generate an alternating current (AC) drive signal. Second circuitry configured to generate a direct current (DC) drive signal. Closed loop control circuitry is configured to adjust the DC drive signal based on at least one of the voltage select and current select inputs and at least one of the actual voltage and actual current inputs. The first circuitry may include a push-pull circuit. The second circuitry may include a pulse width modulation (PWM) controller. A high voltage generator may be coupled to the AC and DC drive signals. The high voltage generator may include a high voltage transformer having a pair of primary windings and center tap. The AC drive signal may be coupled to the primary windings and the DC drive signal may be coupled to the center tap.
Abstract:
An apparatus for independent voltage, air pressure, and/or fluid pressure control of multiple material or coating applicators, such as paint spray guns, includes a multiple gun control board that allows a single power supply to provide voltage to a plurality of paint guns and an independent gun control board that can output a different voltage signal for each gun to generate different gun operating voltages, different air pressures, and/or different fluid pressures. The independent gun control board includes a separate relay and potentiometer for each gun to be controlled. The potentiometer is adjustable so that the output voltage of the independent gun control board can be varied. The output voltage can be used to control the paint spray gun operating voltage and/or be sent to a pressure transducer to adjust the air and/or fluid pressure at which the triggered gun operates. The present invention therefore allows independent voltage and/or pressure control of each gun without requiring each gun to have its own separate power supply and pressure regulator, greatly reducing space and the number of components needed to operate multiple guns.
Abstract:
A method and device for monitoring operation of a high voltage generator which converts an input voltage into an output voltage which is higher than the input voltage, by measuring at least one first physical quantity which is representative of the input voltage; deriving at least one parameter from the at least one measured first physical quantity; comparing the at least one parameter with a second measured physical quantity which is representative of the magnitude of the output voltage; and producing a response when a predetermined minimum differential exists between the at least one parameter and the second measured physical quantity.
Abstract:
A method and apparatus for generating a high voltage by converting input power at a low voltage to output power at a high voltage, by: supplying input power to a low voltage unit to produce a periodic signal having a frequency; supplying the periodic signal to a rectifier voltage multiplier of a specific type to cause the rectifier voltage multiplier to produce the output power at a high voltage, wherein the ratio of output power to input power is a function of the frequency of the periodic signal; identifying the type of the rectifier voltage multiplier; and continually adjusting the frequency of the periodic signal toward a value which maximizes the ratio of output power to input power.
Abstract:
An arc preventing electrostatic power supply suitable for operating an electrostatic paint atomizer such as a rotary atomizer. High voltage control is based on the high voltage current, as measured in the ground return path. The power supply is controlled to provide a substantially constant high voltage DC output up to a predetermined current and an output voltage which rapidly drops off as the current increases above the predetermined current. The magnitude of an AC component superimposed on the high voltage DC current is detected to determine incipient arcing. Upon detecting an incipient arcing condition, the output voltage is interrupted for a predetermined short time. When the output voltage is turned back on, it is ramped up from a low level back to the normal high voltage level. While the output voltage is less than a predetermined low level, the sensitivity of the incipient arc detection circuit is increased. The output voltage is again interrupted for the predetermined short time whenever an incipient arcing event is detected.
Abstract:
A method of selecting the optimum value for a series limiting resistor in conjunction with a high-voltage power supply of the Cockcroft-Walton type, wherein the high-voltage circuit is used to deliver an electrostatic field in a volatile atmosphere of the type associated with paint spraying systems.
Abstract:
An electrostatic spray system including a spray device having an electrode for electrostatically charging coating particles emitted from the spray device toward an article to be coated, a high voltage electrostatic supply, and a high voltage insulated electrical cable interconnecting the electrostatic supply and the spray device electrode. The high voltage cable includes a fibrous resistive core, preferably fabricated from silicon carbide fibers, a fiber-restraining layer of insulative thread tightly wrapped spirally around the entirety of the core to prevent fiber ends from projecting outwardly from the core, an outer dielectric sheath, and an intermediate sheath sandwiched between the spirally wound inner fiber-restraining layer and the outer dielectric sheath and having a resistivity lying between that of the inner resistive fiber core and the outer dielectric sheath. The intermediate sheath provides uniform voltage stress distribution in the region surrounding the resistive core, thereby avoiding internal corona sites which cause degradation of the outer dielectric sheath, which might otherwise occur due to the very small diameter of the resistive core coupled with the very high operating voltages used in electrostatic spray coating operations. The intermediate sheath also avoids high voltage stresses at the ends of stray resistive fibers projecting through the spirally wound layer, which might otherwise occur due to the extremely small diameter of the projecting fibers.
Abstract:
An electronic safety device to prevent electrical arcing in electrostatic sprayer apparatus for spraying material such as paint comprises a device for generating a very low voltage AC signal in a fixed supply and control unit and a voltage step-up device in a mobile sprayer. A device sensitive to variations in the alternating current flowing in the conductors linking the generating device to the step-up device is connected to a disabling device capable, for example, of blocking the generating device when too sudden a current variation is measured, since such a current variation may precede electrical arcing.
Abstract:
Control of high voltage is effected using apparatus having a high impedance generator, the output being connected to a first member of low radius of curvature and a second member. The two members are spaced apart by a gas gap so that when the voltage between them exceeds a threshold value corona discharge across the gas can occur. Such apparatus is particularly useful in controlling voltage and hence the size and size distribution of liquid droplets in electrostatic spraying apparatus.