Nordson Corporation

Fire Sentry Systems, Inc.

Don R Scarbrough

Masafumi Matsunaga

Douglas C Mulder

Lawrence J Macartney

Ronald E Niemiec

Joseph A Pintelon

Harald Pleuse

Donald R Hastings

David A Castleman

Glen A Herstek

Robert C Lindrud

An apparatus for spraying powder coating material includes a rotatable turret which moves articles to and from a work station. A powder spray gun is operable to spray a pattern onto each of the articles in turn while the article is at the work station. The powder flows through the spray gun as a series of pulses. A diverter assembly is operable to divert a portion of each pulse of powder away from the nozzle to more sharply define the pulse. An excess powder collector draws a flow of powder away from the work station. A virgin powder container supplies powder to a powder collector container which supplies powder to a powder feed container which supplies powder to the spray gun. Sensors associated with the virgin, collector and feed containers ensure that a predetermined quantity of powder is maintained in each container. During transport of powder from the virgin and collector containers, the containers and their associated pumps are vibrated to facilitate the flow of powder. The powder spray gun is mounted on a three axis adjustment assembly to enable the powder spray gun nozzle to be accurately positioned relative to an article at the work station.

Methods and apparatus for applying powder to workpieces

A system and method for coincidence detection of ungrounded or inadequately grounded parts during the electrostatic coating process in order to improve production flow, provide an overall cost saving by efficient use of the coating material and prevention of accidental fires and false shutdown during production. The present invention utilizes a coincidence detection technique which performs a test for radio-frequency electromagnetic energy radiated by sparking and/or corona discharge caused by ungrounded parts outside a electrostatic coating area and a test for sensing and discriminating spurious radio-frequency electromagnetic energy radiated by sparking and/or corona discharge caused by any other external source. In accordance with one specific embodiment, the test performed outside the booth may include a further test for detecting ultraviolet energy radiated by the sparking and/or corona discharge. Upon detecting an ungrounded part, the part may be removed from the production line and appropriate steps to properly ground it may be taken. Performing coincident tests thus prevents false shutdowns in the production line.

System and method for coincidence detection of ungrounded parts with

A system for detecting fire in a powder spray booth having a spray gun for depositing powder onto products moving through the booth includes a switch mounted to the spray gun which is operatively connected to a control system which operates the booth and controls the supply of powder to the spray guns. A spring biases the switch toward an open, operating position in which a signal is sent to the control system to shut down the booth operation and powder supply. Under normal operating conditions, the spring force is overcome by a switch closure mechanism which comprises a fixed rod, and a movable rod mounted to the switch which is pulled toward the fixed rod to close the switch by a burnable filament extending between the rods and positioned in the path of the powder discharged from the spray gun. If a fire starts in the booth, the burnable filament is immediately destroyed and releases the movable rod so that the spring is permitted to move the switch to the open position. In turn, the switch sends a signal to the control system to shut down the supply of powder to the spray guns to extinguish the fire.

System for detecting fire in a powder spray booth

A method of substantially eliminating corona discharge at the high-value resistor of an electrostatic spray gun comprises the steps of inserting an insulating tube within a bore formed in the gun barrel, positioning a high-value resistor in the insulating tube, filling a portion of the insulating tube with a slug of dielectric material such as grease and then inserting a high voltage cable into the insulating tube so as to force the grease ahead of the cable. The grease encapsulates the resistor and flows into the space between the insulating tube and bore in the gun barrel to eliminate the presence of air around the resistor so as to prevent corona discharge.

Method of reducing corona discharge in an electrostatic spray gun

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Elyria, OH, United States of America

Don R Scarbrough