Patent Application
20150097051
I. Field of the Invention
The present invention relates generally to cleaning devices and, more particularly, to a cleaning device for cleaning the paint spray tip of a spray gun.
II. Description of Related Art
Industrial spray painting equipment is widely used throughout the industry in many different applications. For example, robots manipulate paint spray guns in the automotive industry in order to paint automotive vehicles as well as components for those vehicles.
In many applications it is desirable, indeed oftentimes required, to clean the spray tip of the paint sprayer between spraying operations. Otherwise, accumulated paint on the spray tip for the paint sprayers can result in paint drip, uneven paint spray, as well as other aesthetic defects. When this happens, it is oftentimes necessary to completely remove the paint sprayed on the article and then repaint the article. This, however, is costly and time consuming.
There have, however, been previously known devices for cleaning the spray tips of paint sprayers of the type manipulated by robots. For example, U.S. Pat. No. 7,467,634 to Jessup, entitled “No Contact Spray Apparatus Cleaning Device”, discloses a non-contact device for cleaning the spray tip of a robotic paint sprayer. In this previously known device, the paint spray tip is inserted through an opening in the top of a housing and sprayed with a solvent for the paint. After spraying, drier air is discharged on the paint spray tip in order to dry the paint spray tip. In addition, downdraft nozzles contained within the housing create a downdraft or a partial vacuum within the housing to draw air flow down through the opening in the top of the housing and across the paint spray tip.
These previously known devices for non-contact cleaning the paint spray tip of a spray gun have proven entirely adequate when used with solvent-based paints. For such solvent-based paints, the drier air flow has proven more than satisfactory for completely drying the paint spray tip after cleaning by the solvent.
However, due to government regulations as well as other concerns, many industries have shifted from solvent-based paints to water-based paints. With these previously known devices for non-contact cleaning of the paint spray tip of the spray gun, the spray tips are oftentimes not adequately dried upon removal from the device. While adequate drying of the paint spray tip may be achieved by increasing the cycle time for the non-contact cleaning device, such increased cycle time unacceptably increases the cycle time of the overall painting operation. This, in turn, increases the overall cost of the painting operation.
The present invention provides an apparatus for non-contact cleaning of a paint spray tip of a spray gun which overcomes the above-mentioned disadvantages of the previously known devices.
In brief, the apparatus of the present invention comprises a housing having a top and an opening in the top dimensioned to receive the spray tip so that the spray tip does not contact the housing. Typically, the spray tip is mounted on a spray gun manipulated by a robot.
At least one drier nozzle is attached to the housing so that a discharge from the drier nozzle impinges against the spray tip as the spray tip is withdrawn from the housing. Preferably, a plurality of drier nozzles are placed at circumferentially spaced positions around the housing opening so that air from the drier nozzles impinges against all sides of the spray tip.
At least one, and preferably several circumferentially spaced solvent nozzles are also mounted in the housing and are oriented to discharge solvent on the spray tip once the spray tip is positioned in the housing opening. The solvent nozzle is connected to a solvent passageway formed through the housing and then to a source of pressurized solvent. The actual solvent will, of course, depend upon the type of paint that is sprayed by the spray gun.
The housing also includes a heater fluid passageway in close proximity to the solvent passageway as well as the drier air passageway. Preferably, all passageways extend through one or more heat sinks within the housing. Thus, the heat from the heated water flowing through the housing simultaneously heats both the drier air as well as the solvent. This, in turn, facilitates faster and complete drying of the spray tip following a cleaning operation, particularly in the case where the paint is a water-based paint.
At least one down flow nozzle is positioned beneath the housing opening and is oriented in a direction away from the housing opening. The flow of compressed air through the down flow nozzles effectively creates a lowered pressure region below the housing opening thus drawing air from the drier nozzles downwardly through the housing and across the spray tip.
A better understanding of the present invention will be had upon reference to the following detailed description when read in conjunction with the accompanying drawing, wherein like reference characters refer to like parts throughout the several views, and in which:
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A solvent passageway 90 is formed within the heat sink 40. Furthermore, a tube 92 constructed of a material having high thermal conductivity is preferably positioned within the heat sink 40 to fluidly connect the solvent passageway 90 to the solvent nozzles 64 through an opening 72 in each heat sink corner ledge 66.
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In operation, upon connection of the down flow nozzles 80 to the source 82 of pressurized air, pressurized air is expelled from the nozzles 80 downwardly and below the opening 14 in the housing 12. This, in turn, creates a partial vacuum below the housing opening 14 which serves to induct air flow from the air drier nozzles 48 down through the housing opening 14 and across the spray tip 18 when positioned within the housing opening 14.
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The heated fluid passageway 68 is in close proximity to both the drier air passageway 54 as well as the solvent passageway 90. Consequently, since the heated fluid passageway 68 is thermally coupled to both the drier air passageway 54 and the solvent passageway 90 by the heat sink 40, the hot fluid flow through the heated fluid passageway 68 effectively heats both the drier air in drier air passageway 54 as well as the solvent in solvent passageway 90 prior to their respective discharge against the spray tip.
In operation, during a cleaning operation a spray tip 18, following a paint spraying operation, is inserted through the housing opening 14 and into the interior of the housing. Upon insertion, spray from the solvent nozzles 64 impinges upon and washes the paint from the spray tip. Simultaneously, air spray from the air drier nozzles 48 is inducted by the partial vacuum created by the downdraft nozzles 80 so that the air flows downwardly and across spray tip 18 thus drying the spray tip 18. Furthermore, as the spray tip 18 is withdrawn from the housing opening 14, the continued air flow from the air drier nozzles 48 completely dries the spray tip 18 in the desired fashion.
A primary advantage of the present invention is that the flow of the heated water through the heater fluid passageway heats both the drier air as well as the solvent. This, in turn, speeds the drying of the solvent from the spray tip 18 to a short time period in preparation for the next spraying operation. The short time period for cleaning and drying the spray tip 18 shortens, and thus enhances, the overall cycle time of the cleaning apparatus 10 of the present invention.
From the foregoing, it can be seen that the present invention provides an effective non-contact cleaning apparatus for a paint spray tip of a spray gun. Having described my invention, however, many modifications thereto will become apparent to those skilled in the art to which it pertains without deviation from the spirit of the invention as defined by the scope of the appended claims.
