Abstract: The invention refers to a method of detecting workpieces in an electrostatic coating system, comprising at least one electrostatic coating device, which applies a high voltage to a high voltage electrode, in which the high voltage electrode generates a spray current including electrostatic charges for charging particles of a coating medium to be sprayed, an electrically conductive workpiece to be coated is moved past the coating device, the spray current of the high voltage electrode is determined and it is detected in accordance with the magnitude of the spray current whether the workpiece is in front of the coating device.

Abstract: The invention provides a method for determining the composition of fluidizable solid matter particles, such as powder particles, in which the solid matter particles are fed through a measuring resonator device comprising a high frequency resonator under defined feeding conditions, and a change of the resonant frequency and/or the amplitude of the high frequency resonator is detected in the measuring resonator means, said change being caused by the fed solid matter particles.

Abstract: The invention refers to a method of controlling a coating device, which discharges a coating medium such as a powder or wet lacquer to a workpiece, in which in accordance with the shape of the workpiece the shape of the cloud of the coating medium discharged is automatically adjusted by changing at least one of the velocity, and the quantity, and the mass flow of the coating medium discharged or shaping air. The invention further refers to a coating installation capable of operating by this method.

Abstract: A device and method of measuring and controlling the flow rate of a fluid determine analog process variables which are dependent on a volumetric flow of the fluid, and the values thus obtained are converted into digital values, the latter being corrected by an offset value which is dependent on a change of the operating parameters of analog components of the measuring system occurring in the course of operation of the system. To obtain the offset value, an analog process variable is determined during interruptions in operation, when the volumetric flow is zero, and converted into a digital value. This digital value is memorized and used as the offset value when operations are resumed. The digital corrected measured values are supplied to a digital signal processor and the flow rate control is carried out digitally. Preferably, at least one parameter memory is provided for the digital control.

Abstract: A method of photothermally examining workpiece surfaces, wherein an electromagnetic exciting beam is directed from a measuring unit to a point to be measured on the workpiece surface so as to heat the workpiece surface at that point and, furthermore, the heat radiation emitted from the point to be measured is detected and analyzed, is characterized in that a plurality of selected points to be measured on the workpiece surface are irradiated by at least a partial beam of the exciting beam, and the heat rays issuing from the points to be measured are sensed and subjected to joint analysis.

Abstract: Apparatus and method of determining the surface condition of a workpiece, operate by measuring a roughness profile of the surface across a certain measuring distance, splitting up the roughness profile into wave frequencies and amplitudes associated with them, dividing the wave frequencies into wave frequency ranges, and determining the surface condition of the workpiece based on the amplitudes in the respective wave frequency ranges. The roughness profile may be understood as the superpositioning of harmonic oscillations having certain wavelengths and amplitudes. By subjecting them to a Fourier analysis, these harmonic oscillations are split up into their wave frequencies and associated amplitudes. Then wave frequency ranges are combined to form bands such that a high intensity in one of the bands each corresponds to a certain physical appearance of the surface. The invention thus provides an objective, calculable measure of the surface condition of a workpiece.

Abstract: A nondestructive workpiece testing method and apparatus are provided, wherein an electromagnetic, intensity modulated excitation beam is directed at a point of examination on a workpiece surface, and wherein thermal radiation emitted by the point of examination is detected and evaluated, the excitation beam being guided periodically in different directions in each one of which it is directed at a different point of examination on a workpiece surface. Moreover, an apparatus is provided for nondestructive workpiece testing, comprising an excitation source for the emission of an electromagnetic excitation beam, an optical means to modulate the intensity of the excitation beam and to direct the excitation beam at a point of examination on a workpiece surface, further comprising a detector means to detect the thermal radiation emitted by the point of examination.

Abstract: A method for photothermally testing workpieces, which includes the steps of directing an electromagnetic excitation beam to a desired measuring point on the workpiece surface, detecting and evaluating the heat in the form of thermal radiation which is generated by the excitation beam at the measuring point with the aid of a measuring head; directing two visible locating beams to the workpiece surface, the two locating beams intersecting at a point of intersection; and correcting the relative position between the workpiece and the measuring head so that the point of intersection and the desired measuring point coincide on the workpiece surface.

Abstract: A cleaning device for a powder coating compartment that comprises a tube system that can be moved back and forth under motor drive through the compartment with a conveyor that passes through a longitudinal slot in the compartment roof and that is equipped with nozzles through which compressed air can be blown against the compartment walls, The tube system comprises two tube branches that are respectively arranged at the contour of the compartment roof and the compartment side walls symmetrically relative to a longitudinal center plane; and in that the compartment floor not swept by the tube system is covered by a discharge belt for eliminating excess powder. The belt is cleaned by a belt cleaning mechanism.

Abstract: A powder injector creates a powder-air mixture and feeds the mixture to a powder coating gun. The injector comprises a powder suction conduit, an injector nozzle fitted in the powder suction conduit, a mixing cone with a venturi tube connected thereto, the mixing cone being disposed downstream of the injector nozzle, a conveying air supply conduit including a control valve for feeding conveying air to the injector nozzle, and a metering air supply conduit for feeding metering air to metering air outlet ports opening into the venturi tube. The metering air supply conduit is composed of two parallel branch passageways branching off the conveying air supply conduit and opening into a common supply conduit leading to the metering air outlet ports. One of the two branch passageways has a metering air control valve disposed therein which is actuated by the air pressure prevailing in the conveying air supply conduit.

Abstract: The invention provides a method of generating a high voltage in an electrostatic powder coating gun with a high-voltage generator having a transformer and a high-voltage cascade arrangement. The primary coil of the transformer is fed with an a.c. supply voltage operating at a working frequency. During operation of the coating gun, the frequency of the supply voltage is continuously varied about the working frequency, the current intensity of the primary coil current of the transformer is also continuously detected and the direction of frequency variation is reversed every time an increase in the current intensity of the primary coil current is determined.

Abstract: An electrostatic powder-coating gun is provided which comprises a powder duct which is connected to a supply conduit for a powder-air-mixture and arranged along the longitudinal axis of the gun barrel and having an open mouth towards the work to be coated, a high-voltage generator, an electrode supporting tube extending through the powder duct in axial direction thereof, and a high-voltage electrode located on the supporting tube and protruding beyond the mouth of the powder duct towards the work. The high-voltage generator and the powder duct are disposed in series along the longitudinal axis of the powder tube in such a way that the powder duct is adjacent the muzzle of the gun barrel. The powder duct is comprised of a toroidal duct and an annular channel extending therefrom and opening to the outside.

Abstract: A process of powder coating of workpieces in which initially a workpiece is coated with color powder such that the powder adheres to the workpiece and subsequently the powder is baked in an oven, in which subsequent to coating and prior to baking the powder adhering to the workpiece is irradiated with electromagnetic radiation within a particular, defined surface portion so that the powder within the defined surface portion will gelate and stick to the workpiece, and in which the color powder adhering to the workpiece outside of said defined surface portion is removed subsequent to irradiation.

Abstract: An apparatus for feeding powder coating apparatus with a powder-air mixture, whereby the powder is fluidized in a reservoir, the powder-air mixture that has thereby arisen is conveyed to a dosing container via conveyor lines and is prepared in this dosing container. The fluidization air is eliminated from the powder-air mixture coming from the reservoir, the remaining powder is re-fluidized and re-dosed in defined fashion, and the powder-air mixture produced is conveyed to the allocated powder coating apparatus.

Abstract: A method of fluidizing, conveying and/or atomizing powdery or liquid coating material in surface coating, particularly in electrostatic surface coating. An inert gas under high pressure is reduced to a lower, operating pressure, whereby it cools to a temperature below the ambient temperature, and is employed as compressed gas for fluidizing, conveying and/or atomizing coating material.

Abstract: In an electrostatic paint spray gun having a built-in high-voltage cascade that is cast into an insulator member together with a transformer, a carrier tube is provided that is composed of a tube section and of an annular flange, whereby the electrical component parts of the high-voltage cascade are arranged and fixed at the outside jacket of the tube section and the output resistors are arranged and fixed at the annular flange. The inside bore of the tube carrier can serve as a receptacle for the high-voltage stranded electrode conductor.

Abstract: In an electrostatic spray gun, particularly a hand spray gun, for coating workpieces with liquid or powdery coating material, the integrated or atached high-voltage cascade comprises a carrier plate of sintered ceramic that is printed with interconnects and capacitor surfaces. The diodes of the high-voltage cascade can also be printed onto a corresponding carrier plate.