US 3572366 A
Description (OCR text may contain errors)
March 23, 1971 R. F. WIGGINS CONTROL VALVES FOR SUPPLYING PAINT IN PAINT SPRAY INSTALLATIONS Filed Oct. 20, 1967 4 Sheets-Sheet 1 ATTORNEYS March 23, 1971 R. F. WIGGINS 3,572,355
CONTROL VALVES FOR SUPPLYING PAINT IN PAINT SPRAY INSTALLATIONS Filed Oct. 20, 1967 4 Sheets-Sheet a FIG. 3
lNVI-TNTOR. RICHARD F WIGGINS ATTORNEYS March 23, .1971 R. F. WIGGINS 3,572,355
CONTROL VALVES FOR SUPPLYING PAINT IN PAINT SPRAY INSTALLATIONS Filed Oct. 20, 1967 4 Sheets-Sheet s INVENTOR RICHARD F WIGGINS FIG. 4
ATTO R N EYS March 23, 1971 R. F. WIGGINS CONTROL VALVES FOR SUPPLYING PAINT IN PAINT SPRAY INSTALLATIONS 4 Sheets-Sheet 4.
Filed Oct. 20, 1967 OmNEDmmwmm ATTORNEYS United States Patent 3,572,366 CONTROL VALVES FOR SUPPLYING PAINT IN PAINT SPRAY INSTALLATIONS Richard F. Wiggins, Fairfield, C0nn., assignor to The Gyromat Corporation, Stratfield, Conn. Continuation-impart of application Ser. No. 440,736, Mar. 18, 1965. This application Oct. 20, 1967, Ser. No. 676,824
Int. Cl. F16k 51/00 US. Cl. 137-240 3 Claims ABSTRACT OF THE DISCLOSURE This invention is concerned with control valves for supplying paint to paint spray installations utilizing a plurality of different color paints. The control valve may be adapted to various systems by utilizing a disclosed flow housing which forms an elongated flow passageway when a number of valves are assembled. The control valve may also be adapted to recirculate paint during periods of valve inactivity to prevent clogging due to the solidification of stagnant paint. The control valve of the invention includes structural innovations, such as manual means for activating a disabled valve. The invention is also directed to a system for automatically purging the installation when the paint supply to a valve is cut oif.
CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of my copending application Ser. No. 440,736, filed Mar. 18, 1965, now US. Pat. No. 3,348,774, issued Oct. 24, 1967.
BACKGROUND AND SUMMARY OF THE INVENTION This invention is concerned with paint supply systems for use in multi-color spray painting installations such as those installations described in my previously mentioned US. Pat. No. 3,348,774. More specifically, the invention provides a control valve for selectively supplying paint or solvent to the spray guns of a spray painting installation and supply systems including an assemblage of control valves to accomplish various objectives which will be discussed in detail hereinafter.
In accordance with a specific aspect of the invention, a control valve is provided with a flow housing section having a through passageway and attaching means for connecting the flow housing to that of a similar valve. When connected in this manner, the individual flow housing passageways form a continuous supply passageway of relatively uniform cross section which is selectively fed by all of the supply valves and which in turn ultimately feeds the spray guns of the spray painting installation.
Each individual control valve flow housing passageway is defined, in part, by a longitudinally movable valve head which is on the lower end of a valve stem and controls the flow of fluid into the flow housing passageway. The valve head seat in a valve seat located in the lower end of a valve housing that contains a passageway for the valve stem.
The supply valve farthest upstream may be used as a solvent supply valve to supply purging fluid to the system during the purging cycle. Since this single purge fluid supply valve is upstream from the paint supply valves, all lines feeding the spray guns and contaminated with the previously used paint will be flushed by the solvent supplied by this valve.
Each control valve of the assemblage is provided with two conduits communicating with each other in the valve 3,572,366 Patented Mar. 23, 1971 housing passageway and with the flow housing passageway. These conduits typically are used as paint and solvent inlet nozzles with the solvent supply nozzle feeding the valve upstream from the paint supply nozzle so that all contaminated internal surfaces of the valve are flushed during the purge cycle.
The provision for purging each individual valve after use permits an assemblage comprising two paint supply valves as previously described, with a purge or solvent valve if desired, to be used for alternatively supplying three or more different color paints to the spray guns. By completely flushing the paint supply system including the valve supplying the color it is desired to discontinue using, the second paint supply valve can be used to supply the color paint it is then desired to spray, and the now flushed, previously used supply valve is rendered inactive and prepared to supply a third color paint when desired. It should be apparent that this sequence can be repeated for as many different colors as one desires. A more detailed description of a typical color change cycle as contemplated by the invention will be found in my above referred to US. Pat. No. 3,348,774, and a discharge system for use in conjunction with the color change cycle is described in detail in my copending application entitled Purging System for a Spray Painting Installation filed on or about even date.
Where economically justified, an assemblage of valves of the type mentioned above may include a separate, individual control valve for each of a multitude of different color paints. Such a system has the advantage of being operable on a substantially fully automated basis, since color changes may be effected without disconnecting and reconnecting paint supply lines. Maintenance of a system of this type can also be minimized by continually circulating paint through inactive valves, thereby preventing clogging of the valve by the solidification of stagnant paint.
In a system wherein a separate paint supply Valve is provided for each color paint, it is not necessary to purge the valve itself during the purging cycle. It is therefore practical, in such an installation, to utilize the solvent inlet nozzle to recirculate the paint back to the paint supply receptacle when the valve is inoperative.
In accordance with another aspect of the invention, a pair of control valves of the general type previously described may be joined to opposite ends of a simplified connecting member, advantageously having a longitudinal passageway and a traverse outlet flow passage. The valves are oriented to position their respective valve seats opposite one another and thereby forming a chamber, the ends of which are defined by the two valve seats and the sides of which are defined by the walls of the connecting membet. The transverse outlet flow passage of the connecting member is located in the chamber between the respective valve seats, and ultimately feeds either paint or solvent to the spray guns of the spray painting installation. In effect, the connecting member serves substantially the same function as the previously described flow housing, with attendant advantages to be described shortly.
The last described assemblage of control valves can be used advantageously in a multi-color paint spray system utilizing three or more different colors. It should be noted that by utilizing this assemblage in a multi-color paint spray installation, a separate purge fluid supply is not required. This is enhanced by the facing relationship of the two control valves. During the purge cycle, the just-used valve is purged by solvent which also flushes the chamber formed in the connecting member up to and including the seated valve seat of the other control valve. The solvent then flows from the chamber to the spray guns through the traverse outlet flow passage and connecting lines and eventually to a purging discharge system.
After the purging cycle is completed, the previously inactive control valve is activated and supplies a second color paint to the system. The now inactive valve can be connected to a third color paint supply receptacle during the spray cycle of the second color paint and thus be ready for use when the system is purged of the second color paint.
Advantageously, each solvent inlet includes a check valve to prevent paint supplied to the control valve from backing up into the solvent supply system. In conjunction with the solvent inlet check valves, the paint supplied to the control valves at a higher pressure than the solvent, thereby preventing solvent flow into the valve when paint is being supplied and automatically causing solvent to flow into the control valve through the check valve when the paint supply is shut off. A significant aspect of the invention is, therefore, the provision of a purging system that automatically supplies solvent to the paint spray installation in response to the shutting off of a paint supply.
Another significant feature of the invention is the provision, in a valve arranged to be remotely actuated by pneumatic or other means, of a novel, manually operated mechanism for activating a control valve that has become inactive due to a mechanical failure in its activation mechanism. Such a failure can possibly occur with any type of activation mechanism and may be expected to occur periodically with an air bellows mechanism, as is typically and advantageously used in conjunction with the valves of this invention. When an activation bellows fails, the valve head seats and cuts off the supply of paint to the system. Since multi-color spray paint installations of this type are used to paint articles moving on a production line, it is highly desirable to continue spraying the particular color in use until the end of its run even after a breakdown occurs and without having to stop the production line to repair the disabled valve. The manually operated mechanism of the invention, while being simplified and inexpensive, permits the disabled valve to continue supplying paint during its active portion of the painting cycle and to be subsequently repaired While it is inactive. This aspect of the invention, therefore, saves valuable production time by not forcing a production line shut down while the disabled control valve is repaired.
BRIEF DESCRIPTION OF THE DRAWING For a better understanding of the invention, reference should be made to the following detailed description and drawing, in which:
FIG. 1 is a top plan view of an assemblage of control valves in accordance with the invention;
FIG. 2 is an elevation view of the assemblage of FIG. 1;
FIG. 3 is a cross-sectional view of an individual control valve of the invention, taken along line 3-3 of FIG. 2;
FIG. 4 is a partial cross-sectional view of a modified control valve of the invention, taken along line 4-4 of FIG. 5;
FIG. 5 is a partial cross-sectional view of an assemblage of modified control valves in accordance with the invention, taken along line 55 of FIG. 4; and
FIG. 6 is a partial cross-sectional view of an advantageous form of two valve paint supply systems in accordance with the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT With reference now to FIGS. 1-3, there is shown a control valve assemblage generally indicated by the reference numeral 24, according to the invention, which is particularly suited for incorporation in the spray paint system disclosed in my beforementioned US. Pat. No. 3,348,774. The illustrated assemblage includes four con- 4 trol valves of substantially identical construction, the individual features of which are illustrated in FIG. 3.
Advantageously, each of the primary control valves has two inlets controlled by the valve elements and arranged to discharge fluid into the main flow passage 26 when the associated primary control valve is open. Thus, the purge valve 27 has its inlets connected to a purging air supply line 45 and a purging solvent supply line 46. The air supply line 45 is connected through a check valve 47 and a solenoid operated control valve to an air supply line. The arrangement is such that, when the solenoid operated control valve is open, air under pressure is supplied to the purge valve 27, for discharge into the system upon opening of the purge valve. The solvent supply line '46 is connected through a check valve 49 and a shut-off valve to a solvent supply container. 'Each of the principal control valves 17 and 27-29 is pneumatically or electrically actuated and, for this purpose includes an actuating bellows 30-33 connected to a source of compressed air by means of control lines such as 34 shown in conjunction with valve 17. The control lines can be detached from the actuating bellows 30-33 by the use of quick disconnect couplings 64, 65, thereby permitting a control line to activate more than one control valve. Each valve includes a flow housing provided with a longitudinal flow passage 81 extending from one end to the other. At its end extremities, the flow housing of each valve is provided with outwardly extending flanges 82 adapted to be bolted or otherwise secured to the similar flanges of adjacent valves or to mounting brackets '83.
In the upper portion of each of the flow housings 80, there is a machined recess 84 which extends downward and into open communication with the longitudinal flow passage 81, which is horizontally oriented in the illustrated arrangements. A valve housing 85 having a downwardly projecting machined boss 86 is secured in fluidtight relation to the flow housing- 80, with the boss 86 being received in and maintained in sealed relation with the recess 84. The valve housing 85 is provided at its lower end with a hardened and ground valve seat 87 of annular form, the opening of which communicates with a lower, primary valve passage 88 and an upper, secondary valve passage 89.
An elongated hardened and ground valve stem 90 extends through the valve passages 88, 89, being slidably guided in the secondary valve passage 89. At its lower end, the valve stem has a conical valve head 91 which closes against the annular valve seat 87 in the manner shown, such that the lower surface 92 of the valve head forms part of the wall of the flow passage 81. The arrangement is such that the flow passage 81, from one end to the other of the flow housing 80, is smooth and relatively uniform in cross-section, affording a relatively minimum opportunity to form eddies and collection pockets which would reduce the efiiciency of clean-out.
At its upper end, the valve stem 90 connects with a bellows element 93 which is located within a bellows housing 94 and forms a seal between the housing and the valve passage 89. The bellows is normally urged upward by a spring 95, but is actuated in a downward direction by introduction of pressure fluid (air) into the bellows chamber 96 through a quick disconnect control air fitting 97.
The specific valve illustrated in FIG. 3, which is the downstream paint valve 29, has its flow passage plugged on the downstream side and is provided with a fitting 98 in its bottom outlet port 23, which causes the fluid flow to be discharged into the supply line 21. The valve is also connected to the solvent line 61, through stop cock 59 and to the paint supply line '55 (downstream of the quick disconnect fitting) through the stop cock '57. The paint supply discharges into the primary valve passage 88, while the solvent suply discharges into the secondary valve passage 89, upstream of the paint supply. An upstream paint valve 28, of similar construction to the valve 29, is connected to the solvent supply through a solvent line 60 and a stop cock 58, and to a paint supply through a quick disconnect fitting 62 and stop cock 56, from a paint line 54.
In accordance with one aspect of the invention, a complete installation advantageously incorporates a unitized bank of primary control valves, including a discharge valve '17 and a purge valve '27, as well as a plurality of paint valves 28, 29. Actually, the discharge valve 17 may be located elsewhere in the installation, without inconvenience, but it is particularly advantageous for the purge valve and paint control valves to be arranged in a unitized bank, as shown in FIGS. 2 and 3. Thus, a series of primary control valves including the purge valve and as many paint control valves as may be desired to be used in the system are assembled in end-to-end relation, "with their respective flanges 82 in abutting relation and secured together in a fluid-tight manner by bolts or other suitable means (not shown). The arrangement is such that the flow passages 81 of the respective flow housings are aligned and in communication to form an elongated, relatively smooth passage of relatively uniform cross-section from one end to the other.
In a complete assembly of valves, a suitable plug 99 is inserted in the upstream end of the How passage of the purge control valve 27, while a similar plug 100 is inserted in the downstream end of the flow housing of the downstream paint valve 29. Other suitable plugs close off two of the three openings of the flow housing for the discharge valve 17, while the remaining opening, advantageously at the bottom, is connected with the discharge line 18 through a fitting 101. The discharge valve is thus isolated from the other valves of the installation.
As shown in FIG. 2, suitable plugs 102 close off the bottom outlets of the upstream control valves, while the discharge outlet 23 in the bottom of the downstream control valve 29 is connected with the supply line 21 through the fitting 98.
The entire bank of control valves, as shown in FIGS. 1 and 2, forms a convenient unitary assembly, which is secured at each end to suitable mounting brackets 83.
Referring to FIGS. 4 and 5, a valve of the general type previously described is shown with certain modifications which make it suitable for use in multi-color paint spray installations wherein a separate supply valve is provided for each color. Such an installation may be operated on a substantially fully automated basis, and it is, therefore, advantageous to provide, in a valve for such service, means effective to minimize breakdown and to enable breakdowns, should they occur, to be remedied with a minimum loss of production time.
The valve shown in FIGS. 4 and 5 includes, as one modified feature, a packing 103 sealing olT the valve passage 88 upstream from connections 114, 117. This sealing element has the effect of preventing a fluid flow into the control air line 97 through the bellows elements 93 if the bellows element should happen to fail during operation, but does not inhibit longitudinal movement of the valve stem 90. In this respect, it will be understood that the repeated flexures to which the bellows elements are subjected in use renders them inherently susceptible to failure after a time.
In the event of a breach in the bellows element 93 during operation of the valve, the air pressure inside and outside the bellows element will equalize causing the bellows element to assume its upwardly extended position by the action of the spring 95. This would cause the valve stem 90 to move upward, seating the valve head 91 in the valve seat 87 and stopping the flow of paint into the paint spray system.
Paint spraying installations of this type often are used to paint objects moving on a production line. In a com-' plex system, a predetermined number of objects may be painted a particular color according to a computerized plan, after which the paint spray system is purged and a second group of objects is sprayed with a different color paint. With this in mind, it is apparent that if a supply valve should break down during the period it issupplying a particular color paint to the spraying system, the entire production line might have to be shut down while the valve is repaired. Obviously, this could be a very costly and undesirable produced. Losses due to such shut downs are minimized by the inclusion in the valve of this invention of a single and convenient manually operated mechanism, shown generally as 104 in FIG. 4, for immediately reactivating a disabled valve without having to shut down the production line. The disabled valve is permitted to complete its cycle with an inconsequential interruption in production and can be subsequently repaired during a period of inactivity.
The manually operated mechanism 104 comprises a main sleeve 107, threadably connected to the top of the bellows housing 94, and cap 105, having a closed upper end and threadably mounted on the main sleeve 107. The cap 105 has a recess, closed by an abutment surface 112, into which an indicator stern 108 projects when the valve head 91 is seated. The indicator stern 108 is fixed to the upper section of the bellows actuating mechanism 110 and reflects the position of the bellows element 93.
During operation of the valve, pressurized air is supplied to the bellows chamber and urges the bellows element 93- downward, which in turn moves the valve stem downward, causing the valve head 91 to unseat. The indicator stem 108 also moves downward and at least partially out of the cap recess and away from its end surface 112. In the event of a breach in the bellows element 93 during operation, the bellows element would be moved upward by the spring 95 due to the equalization of pressure inside and outside of the bellows element. Consequently, the valve head 91 is seated by this upward movement of the be lows element, and the paint supply is cut off from the spray painting system. The indicator stem 108 also moves upwardly and toward an abutting relationship with the abutment surface 112. The condition of the valve can be determined by observing the indicator stem 108 through a window 113 provided in the cap through which the upper end of stem 108 is visible when valve head 91 is seated.
To reactivate a disabled valve, the cap 105 is unscrewed and removed from the sleeve 107, thereby permitting a spacing collar 106 to be removed. The cap 105 is thereafter replaced and screwed down as far as it will go. Since the spacing collar is no longer present, the cap 105 is finally seated farther down on the sleeve 107, as shown in the right hand portion of FIG. 5. In accordance with the invention, the collar 106 has a thickness approximately equal to the longitudinal distance the valve stem must move to fully open the valve head 91. Accordingly, when the cap is replaced after removal of the spacer section, the stem 108 is pressed downward this distance by contact between the upper end of the stem and the abutment surface 112 of the cap. This downward movement of stem 108 is transmitted directly to the valve stem 90, through a connecting element 109. This effects unseating of the valve head 91 and enables continuation of the supply of paint to the paint spray system. The spring 95 urges the indicator stem 108 upwardly and keeps it in solid contact with the cap 105 while the valve is being manually activated. A suitable packing 111 is disposed around the indicator stem 108 to prevent the loss of air pressure in the bellows chamber 96 through the window 113 during normal valve operation.
As previously stated, the control valve described above may be advantageously used in a multi-color paint spray installation having a separate control valve for each color of paint. In such a system, it is not necessary to have a solvent inlet line leading to each of the control valves, since the valve does not have to be flushed during the purging cycle. This permits the conduit normally used to supply solvent to the valve to be used to recirculate paint while the valve is inactive thereby avoiding sett ing or stagnation of the paint in the system.
Thus, in the system shown in FIG. 4, a paint inlet connection 114, feeds paint from a paint supply receptacle 115 to the valve passageway 88 through first paint conduit 116. A suitable pump (P), located in the conduit 1 16 supplies the necessary pressure. When the control valve is inactive, the valve head 91 is seated preventing paint supplied through the inlet connection 114 from flowing into the paint spray installation. A paint outlet connection 117 communicates with the paint inlet connection 114 in the valve passageway 88 and is connected to the paint supply receptacle by a second conduit 118. A pressure regulator (PR) is located in the second conduit line 118 enabling the spray pressure to be maintained according to requirements.
During periods of valve inactivity, the pump (P) continuously circulates paint through the valve and back to the supply recetpacle 115 at a constant pressure determined by the pressure regulator (PR), so that the paint is at all times in a condition for immediate use.
When the valve is activated, paint supplied to the passageway 88 flows into the flow housing passageway 81 and eventually to the spray guns (not shown). It should be noted that, typically, even when the control va ve is supplying paint to the system, a portion of the paint will be recirculated back to the paint supply receptacle 115, because the nozzle discharge rate typically will be less than the capacity of the pump.
Referring now to FIG. 6, a paint supply system incorporating a pair of control valves of the general type previously described, is shown. This system is most advantageously suited for use in a multi-color Paint spray installation handling three or more different colors of paint with only two control valves.
A pair of control valves 128, 129, generally as previously described except without the allocated flow housing 80, are disposed opposite each other and connected together by a connecting member 119. The connecting member 119 has a longitudinal internal passageway, which in conjunction with the valve head 91, forms a chamber 121. A transverse flow passage 122 is provided in the connecting member 119 to bring the chamber 121 into eventual communication with the spray guns of the spray paint installation. The arrangement is such that pressurized paint, supplied to an activated control valve through either of paint supply lines 123 or 124, flows into the chamber 121, and then out through the transverse passageway 122 into the spraying apparatus (not shown).
Each of the valves 128, 129 also is supplied with solvent from a pressurized source 140 thereof, through solvent supply lines 125. During a color change cycle, as will be described, a just used valve may be flushed out with a solvent flow, which then continues through the distribution lines to flush out the entire system of the previously used paint and ready the installation to handle a new color of paint.
A significant specific feature of the invention is the provision of check valves 126 in each of the solvent and paint inlet connections 127, 130. The check valves 126 are oriented to permit flow only into the control valves. In conjunction with this feature of the invention, the system includes paint and solvent pressure regulators 141, 142, whereby paint is supplied to the control valves at a higher pressure than the solvent. Because of the higher paint supply pressure, solvent cannot flow into the valve while paint is being supplied, and the check valves 126 associated with the solvent connections 127 prevent the higher pressure paints from backing up in the lower pressure solvent lines. The arrangement provides a substantially automatic purging system that immediately responds to the shut-ofi of paint in an active control valve to supply purging solvent to the valve and to the distribution lines.
Thus, when the supply of paint to the valve is shut oil, pressurized solvent is no longer held back by the higher pressure paint and consequently automatically flushes the valve and associated spray painting apparatus. It is apparent that this assemblage of control valves does not require a separate purge valve for flushing the system during the color change cycle.
At any given time during the operation of this system, one of the control valves is active and the other inactive. When the valve 128 is activated, for example, paint B is supplied to the valve through a supply line 123, paint inlet connection 130, and associated check valve 126. When it is desired to discontinue spraying paint B and to commence spraying paint A, a shut-off valve V is closed, cutting off the supply of paint B. At this point, the valve head 91 of control valve 128 is still unseated and remains so until the end of the purge cycle. Of course, the valve head 91 of the second control valve 129 is seated at this point and remains so at least until the valve head of the first control volve 128 is seated.
When the shut-off valve V is closed, solvent automatically flows into the control valve 128 as previously explained and into the spray system through the passage 122, thereby flushing the system of paint B. After a sufiicient purging interval, the control valve 128 is deactivated, thereby stopping the fiow of solvent into the system, and the second control valve 129 is activated. At this point, the shut-off valve V for paint A is open, and paint A flows through the system.
While the control valve 129 is supplying paint A to the system, the paint supply line 123 can be disconnected from the paint inlet connection 130 for the first control valve 128, and supply line 131 for a third paint, paint C, can be connected thereto. A shut-off valve V for paint C can now be opened and paint C is ready to be supplied as soon as the painting cycle with paint A has been completed and the system has been purged of paint A. It should be noted that this two-valve paint supply system can be used to supply any number of different color of paint and is very eflicient and economical to install and operate.
The control valve of the invention is very versatile in that it may be used effectively in manually operated, semiautomated and fully automated spray paint installations. It can be used efiectively in systems wherein it is desired or economically advantageous to supply more than one color of paint per valve, and can also be provided with recirculating means when used in systems wherein a separate control valve is provided for each color of paint.
The control valve of the invention incorporates structural innovations which contribute to its versatility and simplified operation. A simplified and convenient means is provided for actuating a valve that fails during its paint spraying cycle. This means permits the disabled valve to continue supplying paint and delays its repair until an inactive period. This innovation could substantially reduce the operational cost of multi-color paint spray systems of this type since breakdown of a paint supply valve during operation does not necessitate a production line shut-down while the valve is being repaired.
In conjunction with the means for activating a disabled valve, the invention also provides means for indicating an operational valve. This means permits an interested party to immediately visually determine Whether an individual valve in the system is active or not.
The invention also provides a two valve system for supplying three or more diiferent color paints, that does not require a separate purging fluid valve thereby resulting in a simplified, less costly installation. This system may be operated on a semi-automated basis by supplying paint to the valve at a higher pressure than the solvent and providing check valves in the paint and solvent inlets. In such an installation the solvent flushing cycle is automatically initiated by shutting off the paint supply thereby resulting in simplier and easier to operate system.
In accordance With the invention a supply system combining the advantages of control valves designed to supply a single color paint and those designed to supply a plurality of different color paints may be utilized. This is accompilshed by providing a plurality of control valves continuously serving an equal number of regularly used paint colors with a pair of control valves arranged in the manner of valves 28, 29 of FIGS. 2-3 or valves 128, 129 of FIG. 6, to handle a larger variety of less frequently used colors.
1. A paint supply system for a multi-color paint spray installation, comprising (a) conduit means having a downstream portion communicating with a spray noz zle,
(b) a plurality of paint inlet passageways communicating with said conduit means,
() a solvent inlet passageway communicating with said conduit means,
(d) controllable valving means associated with each of said paint and solvent inlet passageways,
(e) paint supply means for supplying paint to said paint inlet passageways, and
(f) solvent supply means for supplying solvent to said solvent inlet passageway,
(g) said solvent inlet pasageway being disposed in said conduit means upstream of said paint inlet passageways.
2. The paint supply system of claim 1, wherein '(a) each of said paint inlet passageways and said solvent inlet passageway includes a valve seat,
(b) each of said controllable valving means including a valve head operable with said valve seat to selectively interrupt communication between the inlet passageways and said conduit means,
(0) each of said valve heads forming a portion of said conduit means when seated in said valve seat.
3. The paint supply system of claim 1, wherein (a) said conduit means includes a longitudinally disposed supply passageway,
(b) said paint inlet passageways and said solvent inlet passageway intercept said supply passageway transversely along its longitudinal length.
References Cited UNITED STATES PATENTS 2,997,055 8/ 1961 'Cadonau 137240 3,025,871 3/1962 Roth 13723 8 3,219,273 11/1965 Killen 13715X 3,334,648 8/1967 Probst 137-238 3,348,774 10/1967 Wiggins 239-70 3,373,762 3/1968 Korchak 137240 3,403,695 10/1968 Hopkins 137240 CLARENCE R. GORDON, Primary Examiner US. Cl. X.R.