Abstract:
The wall of a powder spraying booth intended to the pulverent coating of work-pieces is comprised of profiled metal plate elements (17, 172) connected to earth connections (21) so that the booth acts has an earthing cage. On the inner sides of the booth there are arranged, by means of an adhering layer (23) based on insulating glue, separated sheets or plates (31), which are also based on electrically insulating glue, which touch each other and which, optionally, also touch the hollow moulding flanges (34) based on insulating glue to be installed in the corners, which are connected by welds (36) or glued so as to form a smooth surface. Thereby, the whole inner side of the booth is configured so as to present a smooth surface without curves, thereby facilitating the cleaning and, owing to the insulation with respect to the earthed outer booth part, the inner side is charged to the same polarity by the spraying powder. The powder which approaches the booth wall is pushed back by electrostatic forces before adhering. Thereby, deposits on the booth wall are substantially reduced.
Abstract:
A booth for applying a powdered coating to the surface of workpieces in which a clean gas zone (47) is joined to the coating zone (18) via the rear wall (14), which is connected to an extractor fan. Located in a recess (21) of the rear wall (14) is a frame-like structure (22), the outer frame (17) of which is split up into individual areas (24) by means of frame cross-members (23), each area receiving a filter element (25), which is housed in an interchangeable cassette, and consisting of a continuous zig-zag shaped or wave-shaped surface-membrane filter strip. Each area of the frame is covered in a leakproof manner by a protective hood (69) in whose hood space (70) periodic pressure pulses are produced by the venturi tube (73) and high-pressure blower (74), which deform the filter element (25) in an oblique manner towards the coating zone (18) and detach the excess powder attached to the membrane applied thereon, which is diverted through a slat-type screen (55) down to the floor of the booth (67) and into a powder container (80). Thorough cleaning can be effected by a second cleaning device arranged in the coating zone or after removal of an interchangeable cassette from the booth.
Abstract:
A stream of carrier gas with powder particles is introduced at the feeding end (2) of a powder pipe (1) in the direction of arrow (3) for coating workpieces. The material of the coating powder, of the powder pipe (1) and of displacement bodies (21, 22) built in the latter have different dielectric constants. At a certain distance from the outlet end (5) is mounted a charging device (12) provided with boosting electrodes (15) projecting inwardly and connected through a protective resistance (15) to a high-voltage supply (17). A rear counter-electrode (7, 26, 27) comprises an earthed conductive body (7). The displacement bodies (21, 22) accelerate the flow of powder particles. The latter come repeatedly in contact with the inner surface (11) of the powder pipe (1) and the displacement bodies (21, 22), communicating negatively charged particles (10) to them, after charge separation, whereas the positively charged particles (4) remain attached to the powder particles. The concentration of negatively (10) and positively (4) charged particles at opposite ends (2, 5) of the pipe is increased through the electrostatic field acting between the boosting electrodes (13) and the counter-electrode (7, 26, 27). The coating powder is thus so highly charged that an outer electrostatic field between a spraying electrode and the workpiece can be dispensed with.
Abstract:
A booth for applying a powdered coating to the surface of workpieces in which a clean gas zone (47) is joined to the coating zone (18) via the rear wall (14), which is connected to an extractor fan. Located in a recess (21) of the rear wall (14) is a frame-like structure (22), the outer frame (17) of which is split up into individual areas (24) by means of frame cross-members (23), each area receiving a filter element (25), which is housed in an interchangeable cassette, and consisting of a continuous zig-zag shaped or wave-shaped surface-membrane filter strip. Each area of the frame is covered in a leakproof manner by a protective hood (69) in whose hood space (70) periodic pressure pulses are produced by the venturi tube (73) and high-pressure blower (74), which deform the filter element (25) in an oblique manner towards the coating zone (18) and detach the excess powder attached to the membrane applied thereon, which is diverted through a slat-type screen (55) down to the floor of the booth (67) and into a powder container (80). Thorough cleaning can be effected by a second cleaning device arranged in the coating zone or after removal of an interchangeable cassette from the booth.
Abstract:
Un chariot (2) se deplacant sur le sol (1) comprend une colonne de support (3) sur laquelle sont fixes de facon reglable en hauteur un support (5) solidarise d'un recipient (6) et des pistolets de pulverisation (8) tenus par des bras (7). Le support (5) est relie a une source d'air comprime au moyen d'un tuyau flexible (11) et a une source de haute tension au moyen d'un cable collecteur (13) qui est branche avec chaque pistolet (8) au moyen d'un cable haute tension (14) passant par chaque bras creux (7). Chaque bras (7) est fixe par un mandrin (47) de facon mobile longitudinalement et pivotante au moins autour d'un axe. Le pistolet (8) est supporte par l'extremite libre du bras (7) de facon a pouvoir pivoter au moins autour d'un axe transversal, et est connecte avec l'un des plusieurs orifices (32) du recipient (6) au moyen d'un tube flexible (44) et d'un injecteur (40). Le recipient (6) comprend un agitateur et des moyens de traitement associes avec chaque orifice (32). Les pistolets (8) qui sont reglables independamment les uns des autres, peuvent etre enclenches et commandes chacun de facon independante au moyen des injecteurs (40) sans qu'une variation dans la pulverisation d'un pistolet ait une influence sur le pouvoir de pulverisation des autres pistolets.
Abstract:
Aus dem Sprühraum (4) einer Pulversprühkabine wird Rohgas mit Beschichtungspulver durch eine hochliegende Auslaßöffnung (17) der Kabinen-Seitenwand (6) herausgesaugt. Dabei sammeln sich die Pulverkörner auf dem Kabinenboden (3) vornehmlich unterhalb der Auslaßöffnung (17). Um den Niederschlag zu vermeiden, wird vor der Auslaßöffnung (17) eine Blende (22) angebracht, die Teil eines Absaugschachtes (211) ist. Dieser ist an seinem oberen Ende in einem Gelenk (23) schwenkbar gelagert und kann mit seinen Seitenwänden an der Kabinen-Seitenwand (6) mit einstellbarer Neigung bei verstellbarer Öffnungsweite von Spalten (39) anliegen. Dicht über dem Kabinenboden (3) bildet er einen Saugschuh (36), der durch einen Saugspalt (37) das Pulver unmittelbar vom Kabinenboden hochsaugt. Absaugöffnungen (331) sind an den Wänden und der Oberseite des Absaugschachtes angebracht. In die Auslaßöffnung (17) kann Rohgas aus fast allen Richtungen parallel und quer zur Seitenwand (6) einströmen. Diese weitgehend laminaren Strömungen treffen sich im Bereich eines die Auslaßöffnung (77) umgebenden Schlitzes (38) bei verminderter Strömungsgeschwindigkeit. So wird das nicht am Werkstück niedergeschlagene Pulver in die Auslaßöffnung eingesaugt, bevor es sich am Boden oder einer Wandung niederschlagen kann.
Abstract:
In der Pulversprühkabine (1) werden die Werkstücke (14) durch den Behandlungsraum (2) hindurchtransportiert und aus der Einsprühöffnung (19) mittels einer elektrostatischen Pulversprühpistole (18) beschichtet. Ein Sauggebläse (5) saugt die durch die Einsprühöffnung (19) eintretende Luft durch ein Zyklonaggregat (3) mit einer Reihe von Zyklonabscheidern (23) und ein Filteraggregat (4) mit einem Filter (31) hindurch. Während sich die Luft nach den Strömungslinien (38) zum Saugkanal (27) stärker ansteigend bewegt, fällt das Pulver überwiegend nach den Flugbahnen (39) ab. Nur ein Teil gelangt in die Zyklonabscheider (23) und wird dort zwischenzeitig durch Schleusenverschlüsse (40) abgelassen. Der dort nicht ausgeschiedene Pulveranteil wird im Filterraum (32), teils nach Abreinigen des Filters (31), niedergeschlagen. Dieser Anteil kann durch Öffnen der Auslaßklappe (63) auf die Siebmaschine (65) des Pulverwagens (8) geleitet und dadurch mit dem Pulver der Zyklonabscheider (23) zusammengeführt oder durch Öffnen der Auslaßklappe (58) in einen Raum (9) geleitet werden, in dem sich ein zweiter Pulverwagen unterbringen läßt. Durch die Einbindung von Zyklonaggregaten in Kabineneinheiten wird der Gesamtaufbau ebenso vereinfacht wie die Reinigungszeit beim Farbwechsel verkürzt wird.
Abstract:
A stream of carrier gas with powder particles is introduced at the feeding end (2) of a powder pipe (1) in the direction of arrow (3) for coating workpieces. The material of the coating powder, of the powder pipe (1) and of displacement bodies (21, 22) built in the latter have different dielectric constants. At a certain distance from the outlet end (5) is mounted a charging device (12) provided with boosting electrodes (15) projecting inwardly and connected through a protective resistance (15) to a high-voltage supply (17). A rear counter-electrode (7, 26, 27) comprises an earthed conductive body (7). The displacement bodies (21, 22) accelerate the flow of powder particles. The latter come repeatedly in contact with the inner surface (11) of the powder pipe (1) and the displacement bodies (21, 22), communicating negatively charged particles (10) to them, after charge separation, whereas the positively charged particles (4) remain attached to the powder particles. The concentration of negatively (10) and positively (4) charged particles at opposite ends (2, 5) of the pipe is increased through the electrostatic field acting between the boosting electrodes (13) and the counter-electrode (7, 26, 27). The coating powder is thus so highly charged that an outer electrostatic field between a spraying electrode and the workpiece can be dispensed with.