Title:
MULTIPLE COLOR PAINT SPRAY SYSTEM
United States Patent 3674205


Abstract:
A multiple color paint spray system for sequentially supplying selected ones of a plurality of colors to a single spray outlet. A pair of parallel paint manifolds are each connected to the sources of a plurality of colored paints and a solvent. Both manifolds are connected to a single spray gun through a two position valve or to a group of guns each having its two position valve. While paint of one color is being supplied to the outlet from one manifold, the other manifold is conditioned by a solvent purge and filled with the next color to be supplied so that color change to the spray gun or guns may be rapidly effected by switching the two position valve or all the valves simultaneously from one manifold to the other. In a second embodiment, a four-way valve is used to simultaneously supply paint of one color to the gun from one manifold to carry the solvent purge from the second manifold to a disposal source.



Inventors:
KOCK ERHARD
Application Number:
05/143309
Publication Date:
07/04/1972
Filing Date:
05/14/1971
Assignee:
CHAMPION SPARK PLUG CO.
Primary Class:
Other Classes:
137/240, 239/112, 239/569, 239/574
International Classes:
B05B12/14; (IPC1-7): E01B/; E05B15/02
Field of Search:
239/112,569,574,1 137
View Patent Images:
US Patent References:
3450092COLOR CHANGE APPARATUS1969-06-17Kock
3373762Multiple fluid delivery system with liquid and gas purging means1968-03-19Korchak
3219273Electrostatic painting system1965-11-23Killen
3155539Electrostatic spray coating methods and apparatus1964-11-03Juvinall
3145930Electrostatic paint spraying apparatus for changing liquids1964-08-25Herklotz et al.
1085502N/A1914-01-27Smith



Primary Examiner:
Wood Jr., Henson M.
Assistant Examiner:
Grant, Edwin D.
Parent Case Data:


CROSS REFERENCE TO A RELATED APPLICATION

This is a continuation-in-part of my co-pending application Ser. No. 007,465, filed Feb. 2, 1970 now abandoned.
Claims:
I CLAIM

1. A fluid control system for supplying a selected one of a plurality of fluids to a single outlet with means for rapidly changing from one selected fluid to another comprising, in combination, a single fluid outlet, a first fluid manifold having a manifold outlet and connected to the source of each of said plurality of fluids, a second manifold having a manifold outlet and connected to said source of each of said plurality of fluids, a plurality of inlet valves for individually controlling fluid flow from each fluid source into each of said manifolds, a manifold selector valve operably connecting either said first or said second manifold outlets to said single fluid outlet, a first and a second dump valve positioned, respectively, in said first and second manifold outlets upstream of said manifold selector valve whereby, while one fluid is supplied to said single fluid outlet through said first manifold, said second manifold can be preconditioned to supply another fluid by opening said second dump valve and filling said second manifold and its manifold outlet up to said open dump valve with said other fluid.

2. The fluid control system of claim 1 which further includes means for purging said manifolds with air to remove all other fluids therefrom.

3. The fluid control system of claim 1 which includes means to close the fluid inlet valve to said first manifold to terminate flow of one fluid and to open another inlet valve to initiate flow of another fluid in said first manifold for a predetermined time prior to shifting said manifold selector valve to initiate fluid flow from said second manifold to said single fluid outlet.

4. The fluid control system of claim 3 which further includes means for opening said first dump valve following movement of said manifold selector valve to initiate fluid flow from said second manifold.

5. A multiple color spray paint system for supplying to a spray gun a selected paint color from one of a plurality of color paint sources and for rapidly changing from one color to another comprising, in combination, a pair of paint manifolds each having a manifold outlet and each connected to the source of each of a plurality of paint colors, a plurality of paint inlet valves for individually controlling paint flow of each color paint into each of said pair of paint manifolds, a manifold selector valve operably connecting one or the other of said manifold outlets to said spray gun, and a dump valve in each of said manifold outlets upstream of said manifold selector valve whereby, while a first color paint is supplied to said spray gun through one manifold, the other of said manifolds can be preconditioned to supply another color paint by opening said dump valve in said other manifold outlet and filling said other manifold and said other manifold outlet up to said open dump valve with said other color paint.

6. The multiple color spray paint system of claim 5 which further includes means for purging said manifolds with air to remove all other fluids therefrom.

7. The multiple color spray paint system of claim 5 which further includes a source of paint solvent connected to each of said manifolds through a pair of solvent inlet valves and means to close the paint inlet valve to said one manifold to terminate flow of said first color paint and to open the solvent inlet valve to said one manifold to initiate flow of solvent in said one manifold for a predetermined time prior to shifting said manifold selector valve to initiate flow of said other color paint from said other manifold to said spray gun.

8. The multiple color spray paint system of claim 7 which further includes means for opening said dump valve of said one manifold after shifting said manifold selector valve to initiate flow of said other color paint from said other manifold.

9. A method of supplying a selected one of a plurality of color paints and for shifting from such selected one paint to another selected paint and supplying it to a paint spray gun from a pair of paint manifolds each having a valved connection to each of said color paint sources and a valved connection to a source of solvent with said manifolds alternately connected to said gun through a manifold selector valve and with each manifold having a dump valve upstream of said manifold selector valve comprising the steps of sequentially (1) closing the valve supplying said selected one color to the one manifold connected to said spray gun and opening the solvent valve to that manifold to initiate flow of solvent through that manifold toward said spray gun, (2) moving said manifold selector valve to connect said other manifold to said spray gun to terminate flow of solvent toward said spray gun, (3) and opening the dump valve of said one manifold to direct solvent flow therethrough.

10. The method of claim 9 which further includes the steps of (4) opening a paint inlet valve to initiate flow of another selected color paint from its source into said one manifold and (5) subsequently closing the dump valve of said one manifold after filling said one manifold with said other selected color paint.

11. A multiple color spray paint system for supplying to a spray gun a selected paint color from one of a plurality of color paint sources and for rapidly changing from one color to another comprising, in combination,

12. The multiple color spray system of claim 11 which further includes means for automatically purging one of said manifolds with solvent through its associated dump valve and for filling it with another selected color paint while said other manifold is supplying paint of a selected color through said manifold selector valve to said gun.

13. The multiple color spray system of claim 11 which further includes means for opening the dump valve and the solvent inlet valve to the manifold supplying paint to said gun a predetermined time prior to shifting said manifold selector valve to connect said other manifold to said gun.

14. A fluid control system for supplying a selected one of a plurality of fluids to a single outlet with means for rapidly changing from one selected fluid to another comprising, in combination, a single fluid outlet, a first fluid manifold having a manifold outlet and connected to the source of each of said plurality of fluids, a second manifold having a manifold outlet and connected to said source of each of said plurality of fluids, a plurality of inlet valves for individually controlling fluid flow from each fluid source into each of said manifolds, a four-way selector valve simultaneously operably connecting one of said manifold outlets to said single fluid outlet and the other of said manifold outlets to a waste outlet, whereby, while one fluid is supplied to said single fluid outlet through said first manifold, said second manifold can be preconditioned to supply another fluid by filling said second manifold and its manifold outlet up to said waste outlet with said other fluid.

15. The fluid control system of claim 14 which further includes means for purging said manifolds with air to remove all other fluids therefrom.

16. The fluid control system of claim 14 which includes means to close the fluid inlet valve to said first manifold to terminate flow of one fluid and to open another inlet valve to initiate flow of another fluid in said first manifold for a predetermined time prior to shifting said four-way selector valve to initiate fluid flow from said second manifold to said single fluid outlet and from said first manifold to said waste outlet.

17. A multiple color spray paint system for supplying to a spray gun a selected paint color from one of a plurality of color paint sources and for rapidly changing from one color to another comprising, in combination, a pair of paint manifolds each having a manifold outlet and each connected to the source of each of a plurality of paint colors, a plurality of paint inlet valves for individually controlling paint flow of each color paint into each of said pair of paint manifolds, a four-way selector valve operably connecting one of said manifold outlets to said spray gun and the other of said manifold outlets to a waste outlet whereby, while a first color paint is supplied to said spray gun through one manifold, the other of said manifolds can be preconditioned to supply another color paint by filling said other manifold and said other manifold outlet up to said waste outlet with said other color paint.

18. The multiple color spray paint system of claim 17 which further includes means for purging said manifolds with air to remove all other fluids therefrom.

19. The multiple color spray paint system of claim 17 which further includes a source of paint solvent connected to each of said manifolds through a pair of solvent inlet valves and means to close the paint inlet valve to said one manifold to terminate flow of said first color paint and to open the solvent inlet valve to said one manifold to initiate flow of solvent in said one manifold for a predetermined time prior to shifting said four-way valve to initiate flow of said other color paint from said other manifold to said spray gun.

20. A multiple color spray paint system for supplying to a spray gun a selected paint color from one of a plurality of color paint sources and for rapidly changing from one color to another comprising, in combination,

21. The multiple color spray system of claim 20 which further includes means for automatically purging one of said manifolds with solvent through said four-way selector valve and said waste outlet and for filling it with another selected color paint while said other manifold is supplying paint of a selected color through said four-way manifold selector valve to said gun.

22. A method of supplying a selected one of a plurality of color paints and for shifting from such selected one paint to another selected paint and supplying it to a paint spray gun from a pair of paint manifolds each having a valved connection to each of said color paint sources and a valved connection to a source of solvent with said manifolds alternately connected to said gun through a selector valve comprising the steps of sequentially (1) closing the valve supplying said selected one color to the one manifold connected to said spray gun and opening the solvent valve to that manifold to initiate flow of solvent through that manifold toward said spray gun, (2) shifting said manifold selector valve to connect said other manifold to said spray gun and to terminate flow of solvent toward said spray gun and to connect said one manifold to said waste outlet to direct solvent flow therethrough.

23. A multiple color paint spraying system comprising, in combination, a first manifold and a second manifold, a plurality of fluid inlet conduits in fluid communication with each of said manifolds, a manifold outlet conduit extending from each of said manifolds to a common selector valve downstream of said manifolds, a paint spray outlet and a waste disposal outlet operably connected to said selector valve, and means for alternately directing the flow of one fluid from one of said fluid inlet conduits through one of said manifolds to said paint spray outlet and the flow of a second fluid from another of said fluid inlet conduits through the other of said manifolds to said waste disposal outlet.

Description:
BACKGROUND OF THE INVENTION

This invention relates to a paint spray system in which a plurality of paints may be selectively supplied one at a time to a single spray outlet or to each gun of a multiple gun installation. More particularly the invention is a spray paint control system for selectively supplying to the spray outlet one of a number of colored paints and for rapidly changing from one color to another. The invention may be used with electrostatic or conventional spray installations and is particularly useful in high speed finishing applications in which a series of articles to be sprayed or coated are sequentially passed through a coating zone. In such systems, such as in the painting of automotive parts, it is desirable to finish a number of parts in one color and then to rapidly change to another color. The rapid change is, of course, important to prevent the necessity of stopping or slowing the conveyor or leaving a gap between parts on the conveyor while the change-over is taking place.

It is also desirable when changing from one color to another to provide for a means for purging the paint lines leading to the gun with a solvent to remove any paint residue from the previous color, prior to initiating spraying the next selected color. Apparatuses which will feed separate colors to a single spray outlet and which will also permit the operator to clean the spray gun by passing a solvent through it as a part of the color change cycle are known and U.S. Pat. Nos. 3,219,273 and 3,145,930 show devices of this general class.

One of the undesirable features in multiple color spray gun systems which include a solvent purge, particularly such as those shown in U.S. Pat. No. 3,155,539 and in my earlier U.S. pat. No. 3,450,092, is that, in flowing solvent through the paint lines and gun to remove the residue of the previous paint, the solvent leaving gun enters the painting zone or spray booth which increases the fire hazard due to the volatility of the solvent. This is particularly true in systems where the solvent purge is conducted at an increased flow rate which is necessary to reduce the time for color change in order to keep pace with the movement through the spray zone of the objects being coated. The increased flow rate, due to increased supply pressure, will cause an increase in the spray area of the exiting solvent to further compound the fire hazard.

SUMMARY OF THE INVENTION

This invention provides a control system for a paint spray apparatus which is capable of rapidly switching from one selected paint color to another, which includes a means for providing a solvent purge to remove paint residue from the entire system except for the relatively short passages within the spray gun itself and which does not allow any solvent to enter the spray zone. These objects are accomplished through use of a pair of parallel connected paint manifolds which are each connected to the sources of colored paints and solvent and with each manifold connected to the spray gun or guns through a two position manifold selector valve. This valve is moved to alternately connect one or the other manifold to the spray gun. When multiple guns are used in one installation for spraying the same color, each gun may have its own manifold selector valve which are switched simultaneously so that all guns are shifted from one manifold to another.

Positioned adjacent the manifold selector valve and in the line connecting it to the manifold is a dump valve for each manifold which, in one position, allows the paint from that manifold to the manifold selector valve and, in the other position, directs paint from that manifold to a waste dump, bypassing the manifold selector valve. In a second embodiment a four-way manifold selector valve is used to simultaneously supply paint of one color to the gun from one manifold and direct a solvent purge from the second manifold to a disposal source. With this system, and suitable valve controls, one manifold can be purged and filled with the next selected color paint while the other manifold is still supplying a first selected color paint to the spray gun. Upon movement of the manifold selector to connect the other manifold to the gun, only a small amount of the old paint residue must be forced out through the gun prior to initiating spraying with the newly selected paint and no solvent enters the spraying area. The operation and advantages of this system will be more fully understood from the following detailed description of a preferred embodiment thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the dual manifold paint supply system of this invention, showing paint manifolds I and II each connected to a pressurized source of air, solvent, and paint colors A-D. The outlets of the manifolds I and II are shown connected to a single spray gun through the manifold selector valve.

FIG. 2 is a schematic diagram of a second embodiment of the dual manifold paint supply system of the invention showing the outlets of manifolds I and II connected to a four-way manifold selector valve.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, a pair of paint manifolds, designated I and II, are shown with each having an elongated flow passage 10 extending throughout its length with the lower end of the flow passage 10 connected to a manifold outlet line 11. As schematically shown in the drawing, each manifold is formed by a plurality of valve segments which are secured together in a row to form an elongated manifold having a common flow passage extending throughout its length.

As illustrated in the broken away portion of manifold II, a series of inlet valves, each one contained in a valve segment, is connected to the flow passage 10 from top to bottom. Each of the corresponding inlet valves in each of the manifolds is connected through fluid supply lines 12-17 to a pressurized source of air, solvent and paint colors A-D. It should be understood that any number of paint colors can be utilized in this system with larger manifolds which provide a separate fluid inlet valve for each individual paint color and that the illustrated system which includes only air, solvent and four paint colors is not intended to limit the number of fluids which may be controlled using the principles of the present system.

Each of the fluid inlet valves is pneumatically controlled by an air cylinder which, when actuated, moves to the left in the drawing of manifold II to open the fluid inlet valve for flow from the fluid supply controlled by that valve to the flow passage 10 within the manifold. In the drawing, the inlet valves and air cylinder for manifold I are designated as I-air, I-S (solvent), I-A, etc. while the inlet valves and air cylinders for manifold II are designated in a similar manner. Each of the air cylinders controlling the inlet valves are connected to a source of control air pressure through air lines 18 and 19 leading from a control air supply to branched air headers, each of which are connected to the appropriate air cylinder through electrically controlled air valves 20-31 as indicated. A visual indicator 32 may be connected in each header line between the air valves 20-31 and the appropriate air cylinder. The indicators 32, the details of which are not shown, provide a visual indication of the position, open or closed, of the appropriate paint inlet valve. It is apparent that the fluid inlet valves could also be electrically controlled using a solenoid winding directly acting upon the valves.

The manifold outlet line 11 from each of the manifolds I and II is connected to a manifold selector valve which is a two position valve for alternately connecting one or the other of the manifolds I or II to the spray gun through a spray gun supply line 33. The position of the manifold selector valve is shown as connecting manifold II to the gun supply line 33. The manifold selector valve is pneumatically controlled through air control lines 34 and 35 which are connected to the control air line 18 through a branch line 36 and an electrically controlled air valve 37. The air valve 37, as shown in its lower position, connects control air pressure to the line 34 while, in the upper, dotted line position, the control air is connected to the air control line 35 which will move the manifold selector valve to its other position to connect paint manifold I to the gun.

A pair of bypass or dump valves I and II are connected to the respective manifold outlet lines 11 on either side of the manifold selector valve as shown. The dump valves I and II are pneumatically controlled by electrically controlled air valves 38 and 39 and have an open position, in which the manifold outlets 11 are connected to a dump line 40 which leads to a waste collector 41. In their closed position, the dump valves I and II close communication between the dump line 40 and the manifold outlet lines 11. The position of the dump valves I and II is shown by indicators 42. The dump valves I and II and the manifold selector valve could also be controlled electrically.

The supply of control air to each of the air solvent and paint inlet valves in both manifolds, the manifold selector valve, and the two dump valves I and II is electrically controlled so that a valve control apparatus can be positioned in a control station remote from the spray booth. The electrical control apparatus can be a manually operated push button type in which the operator has an appropriate button for changing the position of each of the valves so that any desired operating sequence, as will be subsequently explained, can be manually controlled by the operator Preferably however, the electrical control for the control air to the valve includes an automatic or semi-automatic cycling device which is preprogrammed in accordance with the speed of the conveyor carrying the articles through the spray booth and desired color variations for those articles so that semi- or fully automatic color change can be preprogrammed into the electrical control apparatus. One such device which has been successfully incorporated and which is representative of a number of mechanical-electrical memory devices is generally known as an "Edon Chain" which is marketed by the Edon Industrial Products Company, 2891 Industrial Row, Troy, Mich. 48084. This device is a driven endless chain having a plurality of movable pins which can be placed along the chain to actuate electrical switches positioned in the path of the pins to open or close circuitry to control the position of the fluid valves in the color change system thus described. Other electro-mechanical memory devices including punch card or tape controlled computers may be readily adapted to program the desired sequence of valve operation in the previously described system and will be apparent to those skilled in the art.

Using the color change apparatus previously described and as shown in the drawing, the following are two examples of an operating sequence which may be used to rapidly effect the change from spraying one color to spraying with another color.

EXAMPLE

Assume that the spray gun is spraying the objects to be coated with paint color A from manifold II. In this condition, which is that shown in the drawing, both of the dump valves I and II are closed, the manifold selector valve is in the position to connect manifold II with the gun, the paint inlet and its air cylinder II-A are open while the valves II-air, II-S and the other paint valves in manifolds II are closed.

Assume that it is desired to spray with paint B for a given time and to subsequently change again to spray with paint C. Manifold I will have been previously conditioned, as will be subsequently described, so that it is filled with paint B in the manifold outlet line 11 up to manifold selector valve. With the controller programmed to switch spraying to paint B and then to paint C, the following valve movement sequence takes place:

1. The manifold selector valve moves to its alternate position to connect manifold I to the spray gun through line 33. This of course cuts off manifold II and the gun changes to paint B as soon as the remaining paint A is pushed out of line 33 through the spray gun.

2. Dump valve II opens.

3. Inlet valve II-A closes and inlet valve II-S opens so that solvent purges the common flow passage 10 through manifold II, pushing paint A out the dump valve II into dump line 40 to the waste collector 41.

4. Inlet valve II-S closes and inlet valve II-C opens, so that the new paint color C pushes solvent out through the dump valve II to fill the lines leading to the manifold selector valve with paint C.

5. dump valve II closes. In this condition, manifold II is now preconditioned to be ready to immediately supply paint of color C to the gun as soon as the manifold selector valve is again moved and the above sequence is repeated on corresponding valves on the other manifold.

In the above described sequence of Example I, it should be noted that solvent never enters the spray booth through the spray gun, that each manifold is preconditioned to spray another color paint while the other manifold is supplying paint to the gun so there is no down time, and that the common flow passage 10 in the manifold and the lines leading up to the manifold selector valve are purged with solvent prior to introduction of another color of paint.

EXAMPLE II

Again assume that paint A being supplied to the gun through manifold II with the manifold selector valve in the position as shown. Assume that manifold I has been preconditioned and filled with paint B, as described with reference to Example I. With the electrical control programmed to switch from paint A to paint B and later to paint C, the following sequence of valve operation takes place:

1. Inlet valve II-A closes and valve II-S opens. In this condition, solvent pushes paint A through the common flow passage 10 of manifold II towards the manifold selector valve.

2. The manifold selector valve moves to its alternate position to connect manifold I and paint B to the spray gun. This stops the flow of solvent through the manifold outlet line 11 until dump valve II is opened. The time delay between the opening of the solvent valve II-S and the switching of the manifold selector valve is such that the solvent which is purging paint A from manifold II will completely clear manifold II itself but will not reach the manifold selector valve. This time interval, is of course dependent upon the length of the manifold outlet 11, and the rate of paint flow and is easily determined for a given installation. This system has the advantage in that while paint A in the manifold is being purged by the solvent, most of the paint A in the system ahead of the solvent is pushed out to the spray gun, thus reducing the amount of paint loss in a color changeover.

3. Valve II-S closes and valve II-C opens so that paint C pushes solvent out of the manifold II and manifold outlet line 11 through the dump valve II.

4. dump valve II closes so that manifold II is now preconditioned to immediately supply paint C as soon as the manifold selector valve is again switched to its position shown in the drawing.

It should be appreciated that in either of the operational sequences described in Examples I and II above, the dual manifold system has the advantage of providing almost instantaneous change from one color to another. Because each of the manifolds is being purged and conditioned with a subsequent paint while the other manifold is still supplying a desired paint to the spray gun, the amount of time for an effective color change is substantially reduced. For example, using a built up manifold of 45 inches in length, the volume within the manifold's internal passages is about 70 cc. When changing from one color to another with an intermediate solvent change, the replaced liquid must be scrubbed in effect by the subsequent liquid so that several volume changes within the manifold are necessary. For example, with a solvent flow rate of 600 cc per minute, it would take approximately 40 seconds to purge that manifold of a previous color with solvent and refill it with a subsequent color. Using the system of this invention, the complete color change can be effected in approximately 2-3 seconds, depending upon the length of the paint supply line 33. It is to be understood that the only time delay in changing from one paint to another in the instant system is that required to flow the new paint through the line 33 to the gun. By positioning the manifold selector valve as close as is possible to the gun, this time is reduced to a minimum.

To further accelerate the paint change cycle, the source of solvent may be under a pressure higher than that of the paint sources so that supply line 13 and solvent flowing through the manifolds I and II when the valves I-S or II-S are open is under higher pressure and thus flows at a higher rate. The higher solvent pressure also improves the purging action in the interior of the manifolds. Such increased solvent pressure does not present any undesirable fire hazards in the present system because no solvent flows through the gun, as would be the case with prior art color change systems.

An air purge to dry the manifold interior and prevent solvent dilution may be included in the present system, using a source of air under pressure connected to the manifold I and II as shown in the drawing. If an air purge following the solvent purge is desired, the operating sequence of Examples I and II would include the step of closing the appropriate solvent inlet valve and opening the appropriate air inlet valve for a predetermined time to push out solvent with air. Finally, it should be noted that in each case, the solvent and air inlet valves are positioned in the manifold at the end remote from the manifold outlet line 11 so that solvent and air purges are effective to scrub the entire length of the common flow channel 10 in the manifolds.

It will be apparent to those skilled in the art that the timing of valve movements in the sequence described in Examples I and II may be varied to fit the desired installation to attain the advantages provided by the dual manifold system of this invention. The timing and sequence of opening and closing each of the valves is, of course, dependent upon the frequency with which the articles to be sprayed are presented in the spray zone and the particular selection of color sequence is, of course, dependent upon the desired color output for the articles being coated.

Referring to FIG. 2, a second embodiment substantially similar in function and structure to the first embodiment described above is shown. In this embodiment, a four-way manifold selector valve 43 is positioned between the outlet lines 11 from manifolds I and II. The four-way manifold selector valve 43 combines the functions of the manifold selector valve and the dump valves I and II shown in FIG. 1.

The four-way valve 43 comprises a body 44 having a valve inlet 45 connected to the manifold outlet 11 from manifold I and a valve inlet 46 connected to the manifold outlet 11 from manifold II; a spray gun supply outlet 47 and a waste disposal outlet 48. A rotatable cylindrical valve member 49 is located within a complementary bore 50 in the body 44. Two curved passageways 51 within the cylindrical valve member 49 provide fluid communication simultaneously from one of the valve inlets 45 or 46 to the gun supply outlet 47 and from the other of the inlets 45 or 46 to the waste disposal outlet 48.

The valve member 49 may be rotated by air actuated means to alternatively direct fluid selected from a color source in one of the manifolds, as described above, to the gun supply outlet 47 and purging fluid from the second manifold to the waste disposal outlet 48. A single dump valve 52 downstream of the waste disposal outlet 47 provides a means for controlling fluid flow from the purging manifold to the waste collector 41.

Thus, for example, when the four-way selector valve 43 is positioned as shown in FIG. 2, a selected color from manifold II is supplied to the spray gun and the solvent and air purge being cycled through manifold I is sent through the waste disposal outlet 48 to the waste collector 41. Prior to effecting a color change, solvent flow in manifold I from the solvent supply line is terminated and flow from a selected color supply line to purged manifold I is initiated, pushing the remaining solvent through the waste disposal outlet 48 and the single open dump valve 52 to the waste collector 41. The color flow through manifold I toward the waste collector is terminated by closing the single dump valve 52. Thus a selected color under pressure is now in manifold I and the manifold outlet line 11 up to the four-way selector valve 43.

To effect color change, the cylindrical valve member 49 is rotated 90° to place the manifold outlet 11 from manifold I in fluid communication with the spray gun supply outlet 47. Since the selected color from manifold I is already in the manifold outlet line 11 prior to shifting the four-way valve 43, the new color will rapidly enter the gun supply line 33 and the gun when the valve 43 is shifted. Shifting of the four-way valve 43 will also place manifold II in fluid communication with the waste disposal outlet 48 as described. The purging cycle is now initiated in manifold II. Thus the four-way valve 43 provides means for simultaneously directing a selected color to the spray gun from one manifold and purging fluid to the waste collector 41 from the second manifold and means for realigning the manifold outlets 11 to exchange color supply and purging cycles from one manifold to the other. Other advantages of the present system in various modifications thereto will be apparent to those skilled in the art and may be made without departing from the spirit and scope of the following claims.