Abstract:
A bulk unloader for emptying powder from an original box-shaped shipping container has a support platform with a cradle angularly mounted thereto for holding the containers in a tilted position so that one of its corners is lower than the others. A vibrator, attached to the cradle, loosens the powder to facilitate movement of the powder towards the container's lowest corner. A pump connected to the outlet end of a hollow pick-up tube, having an inlet end positioned adjacent the container's lowest corner, draws powder from the container, into the inlet end of the pick-up tube, and then transfers the powder to a powder spray gun. The lower end of the pick-up tube is designed to prevent the plastic bag lining the shipping container from blocking the inlet end of the pick-up tube. A vibration dampening isolation mount is provided between the cradle and the support platform to prevent vibrations from being transferred from the cradle to the support platform.
Abstract:
An apparatus for generating a very thin mist of powder with a device for measuring the flow of powder from a supply container and controlling the flow of the powder to an atomization chamber, which includes a device for periodically diverting the flow of the powder past the measuring device so as to determine the effects of aging and impurities on the measuring device and to compensate the measuring device for such effects.
Abstract:
An electrostatic filament coater comprising a plurality of coating chambers arranged coaxially in spaced apart serial relation. Each of the coating chambers has a base and an apex and being generally frusto-conical in shape with an exit opening at the apex and an entrance opening at the base. All of the coating chambers except the last one are positioned with the apex being within the base of the next adjacent coating chamber. The filament is trained through the coating chambers. A plurality of electrodes are positioned within the coating chambers so as to surround the filament. A near arc-over voltage is supplied to the electrodes and a fog of particulate coating material suspended in a gas is passed through the coating chambers and axially of the filament at a velocity which results in the electrostatic deposition of the particulate matter on the filament and the exhaust of the gas and excess particulate matter from between the coating chambers and the apex opening of the last coating chamber. The method of the invention includes the steps of passing a filament through a cloud of particulate coating material suspended in a gas, surrounding the filament with a plurality of spaced apart electrodes, imposing a near arc-over potential to the electrodes and imposing a near arc-over potential to the electrodes to electrostatically deposit the particulate coating material on the filament.
Abstract:
Apparatus and method for electrostatically depositing a layer of particulate material on a substrate surface from a gaseous suspension of particulate, thermoplastic material. Classifying means removes oversized particles from a supply of particulate, thermoplastic material and feeds properly-sized particulate material to a metering feed device. A pressure responsive sensing means is associated with the metering feed device, and energizes a control circuit associated with the classifying means to direct properly-sized particulate material from the classifying means into the metering feed device to maintain a substantially constant, predetermined amount of properly-sized particulate material in the metering feed device. The metering feed device feeds the properly-sized particulate material at a controlled volumetric rate into a gaseous medium to form a gaseous suspension of properly-sized particulate, thermoplastic material which is directed through a plurality of electrically charged spray means onto a substrate surface. The metering feed device includes a housing having a hopper section for receiving particulate material from the classifying means, and an elongate trough section in communication with the hopper section through a gate means. The trough section is divided into separate elongate channels by elongate, transversely spaced partition means which extend for substantially the entire elongate extent of the trough section. Each spray means includes a spray nozzle having an elongate passage terminating at a downstream end in an exit orifice, and a deflector fan positioned downstream of, and in overlying relationship with the exit orifice. Each spray nozzle has an inlet port in a side wall, and an elongate, tapered baffle overlies the inlet port for mixing a gaseous suspension of particulate material entering the spray nozzles through a conduit which is in communication with the inlet port of the spray nozzle and one channel of the metering feed device. Each spray nozzle further includes a discharge outlet chamber downstream of the baffle to confine the flow pattern of the gaseous suspension of particulate material as the gaseous suspension travels through the discharge outlet chamber and out of the exit orifice. The deflector fan associated with each spray nozzle deflects the gaseous suspension of particulate material onto the substrate surface in an elliptical pattern having its major axis disposed substantially transverse to the direction of elongation of the elongate passage. The spray nozzles are mounted on a belt which is movable along a path defining a closed loop having spaced, linear runs which traverse past the substrate surface upon which a layer of particulate material is to be formed. The metering feed device is supported on a rotatable platform, and drive means rotates the belt supporting the metering feed device at a synchronized speed to prevent twisting of delivery conduits which are in communication with the metering feed device and the spray nozzles.
Abstract:
Particulate material spraying apparatus comprises an extractor device having an inlet passage extending from the mouth of an inlet nozzle at one end of the inlet passage and a compressed gas passage extending past the other end of the passage to entrain particulate material through the inlet nozzle and inlet passage, to a flexible pipe leading to a spray gun. To prevent choking by accumulation of the material in or on the extractor device, the inlet nozzle has a tapered outer surface converging with the inlet passage at the mouth, and a vibrator is provided for vibrating the nozzle. The extractor device may be attached to the wall of a container for the particulate material, or may be separate from the container to facilitate transference of the extractor device to a different container.
Abstract:
A coating apparatus with a powder supply system for use in a device for electrostatically spraying powder material onto the surface of an article or substrate to be coated. The system includes a powder reclaiming and recycling system which pneumatically retrieves the unused powder from the spray booths and filters the powder from the air. The filter system includes plural modules, each capable of accommodating a given number of spray guns. An automatic filter shaking system releases the powder from the filters upon command by sequentially shutting down the filter modules, one at a time, while the system is in operation. An additional filter module is provided so that adequate filtering capability is maintained while the filter shaking operation proceeds. The powder released from the filters is blown from the filters to a feeder section through a sieve which mixes new powder with the reclaimed powder under automatic control which replenishes the powder supply to the feeder. The feeder employs a fluidizing bed from which (a plurality of) plural module feeders are fed. The feeders are positioned beneath the bed and draw powder through elongated standpipes for improved powder flow control. This configuration shows complete drainage of the bed and prevents ''''puffing'''' associated with conventional fluidized bed feeders. The feeders are quickly and easily detachable from the system and can be quickly and easily replaced or disassembled for cleaning when material or color change is desired.
Abstract:
In an electrostatic powder spray system wherein resin powder is fed from a supply hopper to a powder dispensing venturi and is propelled therefrom by pressurized air through a conduit to a spray gun, the venturi housing is constructed of insulating material so that resin powder particles electrostatically charged by the triboelectric effect are not attracted to the venturi housing walls and do not clog the venturi.
Abstract:
The fluidizer and dispenser has a storage container mounted above the fluidizing chamber and a valve system to meter small increments of pulverant material from the storage container to the fluidizing chamber. The fluidizing element comprises a cylinder having an air nozzle and fluidizing plate and a diffuser plate extending across its lower area to provide a fluidized bed of pulverant material in the region above the plate. Part of the fluidized bed of pulverant material is aspirated by means of the jet into a conduit through which it is conducted in air solution. Fluidized pulverant material is conducted to a nozzle and there sprayed onto a can or other surface.
Abstract:
An apparatus for feeding and dosing powder includes a powder storage container, an oscillating feeder with feeder with adjustable feeding rate for dispensing the powder to a powder outlet, a conduit arrangement for feeding the powder dispensed from the oscillating feeder in a feeding gas as a powder-gas mixture and for supplying the powder-gas mixture to a powder processor, wherein a decoupler is provided in the conduit arrangement to extract a defined proportion of the powder from the powder-gas mixture, a powder quantity measuring arrangement for detecting the decoupled powder quantity and for providing a powder quantity information signal, wherein the extracted powder quantity has a predetermined ratio to the fed powder quantity of the oscillating feeder, and controller configured to adjust the adjustable feeding rate of the oscillating feeder to a predetermined set value based on the powder quantity information signal provided.