SPRAYER WITH REVERSE FLUSH CAPABILITY

Abstract: A method for flushing an airless sprayer comprising a sprayer (210) having an inlet and an outlet and being attached to a pump (212) having an inlet and an outlet and a filter (240) having an inlet and an outlet, said sprayer, pump and filter all having a normal direction of fluid flow and comprising the steps of: supplying said pump inlet with cleaning fluid; connecting said sprayer outlet to said pump outlet; connecting said sprayer inlet to said filter outlet; and pumping said cleaning fluid through said sprayer and said filter in a direction opposite to said normal direction.

Description: SPRAYER WITH REVERSE FLUSH CAPABILITY TECHNICAL FIELD This application is a continuation-in-part of US Application serial number 60/123,630, filed March 10, 1999. BACKGROUND ART Airless and other paint sprayers have been widely used for commercial and other painting purposes for many years. One of the least liked aspects of such units however is the need for cleaning at the end of a day or job. Typically, such cleaning consists of immersing the intake tube of the unit in a bucket of water or other solvent and spraying into a bucket until the fluid coming out of the gun is clean and clear. The amount required can often be many gallons. DISCLOSURE OF THE INVENTION It is therefore an object of this invention to provide an enhanced method of flushing and airless sprayer which is easily accomplished with minimal operator input and which flushes more thoroughly than traditional methods while using less fluid. For flushing, the tip of the airless spray gun is removed, the trigger opened and the gun placed in a container of water or other suitable solvent depending on the material to be flushed. A dump valve control is then operated which connects the gun line to the pump intake and the pump output is connected to the return line which is in turn connected to the suction tube placed in a container to collect the flushed material. The pump is then operated: (1) until the operator sees the output to be clean; or (2) for a predetermined period of time while the operator does other things; or (3) until an opacity detector finds the output to be clear; or (4) until a pressure sensor sees a pressure drop reflecting exhaustion of the cleaning fluid. In an alternate embodiment, a fluid rerouting stem is attached to the front of the spray gun and the pump outlet enabling cleaning fluid to be pumped in reverse through the gun, the filter manifold and out the drain valve into the supply bucket (from whence the cleaning fluid was pumped). These and other objects and advantages of the invention will appear more fully from the following description made in conjunction with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views. BRIEF DESCRIPTION OF DRAWINGS Figure 1 is a schematic view of the instant invention in the standard spray configuration. Figure 2 is a schematic view of the instant invention in the flush configuration. Figure 3 is a schematic view of an alternate embodiment of the instant invention in the standard spray configuration. Figure 4 is a schematic view of an alternate embodiment of the instant invention in the flush configuration. Figure 5 is a schematic view of the preferred embodiment of the instant invention in the standard spray configuration. Figure 6 is a schematic view of the preferred embodiment of the instant invention in the flush configuration. Figure 7 is a partially exploded view of the fluid stem. BEST MODE FOR CARRYING OUT THE INVENTION The sprayer, generally designated 10 is shown in Figures 1 and 2 and is comprised of a pump 12 having intake 14 and outlet 16. Outlet line 18 is connected to outlet 16 and dump valve control 26. Gun line 28 connects control 26 to spray gun 30 having trigger 30a. Dump line 32 connects control 26 to material container 38 while return line 24 connects control 26 to inlet switch valve 20 at port 20a. In the spraying configuration shown in Figure 1 , the suction tube 22 is connected via inlet switch valve 20 to pump inlet 14. Pump outlet 16 sends coating to be sprayed to control 26 via line 18 where it is connected to line 28 and gun 30 (it may also be connected to line 32 for priming). In the flushing configuration shown in Figure 2, gun 30 is immersed in cleaning media 34 and line 28 connected to line 32 at control 26. Line 32 is then connected to pump inlet 14 at inlet switch valve 20. Pump outlet 16 sends the flushing material to control 26 via line 18 where it is connected to return line 24 and thence to intake tube 22 in waste bucket 36 via inlet switch valve 20. After a painter has completed a paint color or job they will be required to get the cleaning media such as water. It will require approx. 5 gals with a small airless sprayer. They should " chase" the painting media with the clean media until they have removed as much of the salvageable material as desired. At this time the user should place the gun 30 with the trigger 30a locked in the open position and the tip removed into the cleaning media 34. Operate the dump valve control 26 to the clean position. Turn the inlet switch valve 20 by 180 degrees to reverse the intake to the gun line 28. Put the pump suction line 22 into an empty bucket 36. Go to the control and switch the sprayer to the " clean" position. The pump 12 will take approx. 2 min to prime and then the sprayer will reverse flush for about 7-9 minutes. When the sprayer shuts down the user can wipe down the stinger or suction tube 22 and empty the waste bucket 36. Wipe down the gun and attach it to the sprayer and the clean up is completed. Figures 3 and 4 show another embodiment 110 of the instant invention. A pump 112 has an inlet 114 and an outlet 116. Outlet 166 is connected via line 118 to the inlet 142 of filter 140. Return port 144 of filter 140 is connected to switch valve 154 via line 152. Control valve 148 also can connect inlet 142 to dump line 124. Spray gun 130 is connected to filter 140 via line 138 at inlet 130b. Gun 130 sprays at outlet 130a. The operation of embodiment 110 for normal spraying is shown in Figure 3. Switch valve 154 is positioned in the first position shown in Figure 3 such that paint or other material to be sprayed is drawn in through intake tube 122 and thence into pump inlet 114. The fluid is then pumped from outlet 166 through line 118 to filter inlet 142 and then from outlet 150 via line 138 to gun 130 where it is sprayed. For cleaning and flushing, control valve 148 and switch valve 154 are positioned as shown in Figure 4. Spray gun 130 is placed in a container of cleaning fluid (water for water based materials or a solvent for solvent based materials) which fluid is drawn into the gun inlet 130a. The fluid is then drawn through line 138 into filter outlet 150 where it reverse flushes filter 140 passing through control valve 148 into dump line 124 where switch valve 154 connects it to pump inlet 114. Pump 112 then pumps the fluid from pump outlet 116 through line 118 to control valve 148 where it is directed to port 144 and line 152 which is connected to intake tube 122 at switch valve 154 and outputted into a bucket or other collector. In the preferred embodiment 210 shown in Figures 5 and 6, pump 212 has an inlet 214 and an outlet 216 which is in turn connected via line 218 to fluid bar 256. Fluid bar 256 has a central passage 258, a filter port 260 and an outlet 262. Filter 240 has an inlet 242 which is connected to filter port 260. Filter 240 also has a drain valve 272 connected to a dump line 224. Filter outlet 250 is connected to spray gun 230 inlet 230b via line 238. For spraying, the sprayer is configured as shown in Figure 5 such that paint or other material is pumped from pump inlet 214 to line 218 and thence into fluid bar 256 which has outlet 262 plugged. The material passes through filter port 260 into filter 240 and thence through line 238 to spray gun 230 where it is sprayed from outlet 230a. For cleaning and flushing, the sprayer 210 is configured as shown in Figure 6. The operator should " chase" the painting media with the clean media until they have removed as much of the salvageable material as desired. Fluid stem 266 has an inlet portion 268 which is inserted into port 262 of fluid bar 256 where it blocks filter port 260. Gun attachment nut 270 allows the other end of stem 266 to be attached to outlet 230a of spray gun 230. In order to do so, the gun tip and guard must be removed and the trigger locked into the on position. In operation, fluid is pumped through pump 212 into fluid bar 256 where it is passed to stem 266 and thence flows in reverse direction through spray gun 230, line 238 and filter 240 where drain valve 272 is operated so that the cleaning fluid is exhausted from line 224. A final step to complete the cleaning process is for the operator to wipe the outside of the intake tube and examine the filters to make sure they have been completely cleaned. The system may be controlled by a processor for any of the embodiments set forth so that the pump is operated: (1) until the operator sees the output to be clean; or (2) for a predetermined period of time while the operator does other things; or (3) until an opacity detector finds the output to be clear; or (4) until a pressure sensor sees a pressure drop reflecting exhaustion of the cleaning fluid. It is contemplated that various changes and modifications may be made to the sprayer without departing from the spirit and scope of the invention as defined by the following claims.

Claims: CLAIMS 1. A method for flushing a paint sprayer having a spray gun with an outlet attached to a pump and filter all having a normal direction of fluid flow and comprising the steps of: supplying a cleaning fluid to said outlet; and pumping said cleaning fluid from said outlet through said gun and said filter in a direction opposite to said normal direction. 2. The method of claim 1 wherein said spray gun is immersed in a container of cleanin *gto fluid. 3. The method of claim 1 wherein said spray gun outlet connected to the outlet of said pump. 4. A method for flushing a paint sprayer having a spray gun having an inlet and an outlet and being attached to a pump having an inlet and an outlet and a filter having an inlet and an outlet, said spray gun, pump and filter all having a normal direction of fluid flow and comprising the steps of: supplying said pump inlet with cleaning fluid; connecting said spray gun outlet to said pump outlet; connecting said spray gun inlet to said filter outlet; and pumping said cleaning fluid through said gun and said filter in a direction opposite to said normal direction. 5. The method of claim 4 further comprising means for detecting the exhaustion of said cleaning fluid. 6. The method of claim 4 further comprising means terminating said pumping in said reverse direction after a predetermined period of time. 7. A method for flushing a paint sprayer having a spray gun having an inlet and an outlet and being attached to a pump having an inlet and an outlet and a filter having an inlet and an outlet, said spray gun, pump and filter all having a normal direction of fluid flow and comprising the steps of: supplying said gun outlet with cleaning fluid; connecting said spray gun inlet to said filter outlet; connecting said pump inlet to said filter inlet; and pumping said cleaning fluid through said gun and said filter in a direction opposite to said normal direction. 8. The method of claim 7 further comprising means for detecting the exhaustion of said cleaning fluid. 9. The method of claim 7 further comprising means terminating said pumping in said reverse direction after a predetermined period of time. 10. An apparatus for flushing a paint sprayer having an intake tube, a drain tube, a spray gun having an inlet and an outlet and being attached to a pump having an inlet and an outlet and a filter having an inlet and an outlet, said spray gun, pump and filter all having a normal direction of fluid flow, said apparatus comprising valve means having first and second positions wherein in said first position said pump inlet is connected to said intake tube, said pump outlet is connected to said filter inlet and said filter outlet is connected to said spray gun inlet such that the sprayer may be operated to spray in said normal and wherein in said second position, said filter inlet is connected via said drain to said pump inlet and said pump outlet is connected to said intake tube such that when said spray gun outlet is supplied with cleaning fluid, said cleaning fluid is pumped opposite said normal direction consecutively through said gun, said filter, said pump and said intake tube. 11. An apparatus for flushing a paint sprayer having an intake tube, a drain tube, a spray gun having an inlet and an outlet and being attached to a pump having an inlet and an outlet and a filter having an inlet and an outlet, said spray gun, pump and filter all having a normal direction of fluid flow, said apparatus comprising valve means having first and second positions wherein in said first position said pump inlet is connected to said intake tube, said pump outlet is connected to said filter inlet and said filter outlet is connected to said spray gun inlet such that the sprayer may be operated to spray in said normal and wherein in said second position, said filter inlet is connected to said drain tube said pump outlet is connected to said spray gun outlet such that when said pump inlet is supplied with cleaning fluid, said cleaning fluid is pumped opposite said normal direction consecutively through said pump, said gun, said filter and said drain tube.

Inventors: DURKEE STEVEN, OLSON DIANE, THOMPSON DAVID, DURKEE, STEVEN, OLSON, DIANE, THOMPSON, DAVID
Applicants: DURKEE STEVEN, GRACO INC, OLSON DIANE, THOMPSON DAVID, DURKEE, STEVEN, GRACO INC., OLSON, DIANE, THOMPSON, DAVID
Application year: 2000
Main classification: B08B9
IPC codes: B05B15, B08B9