CA1039495A - Dispensing apparatus - Google Patents

Abstract

Abstract of Disclosure A spray gun especially adapted for dispensing foam type plastics or other coating materials which is characterized by two feed lines for the coating materials which are encased in return lines with valves which are selectively positioned to control the flow of the material so as to provide, selective-ly, for spray operation or for continuous return flow to the supply source without passage through the discharge control valves of the gun. The discharge control valve assemblies are readily removable as complete units for cleaning and repair. A solvent flush valve is arranged relative to the discharge control valves to enable the valves, the mixing chamber and passageways in the head to be flushed out with solvent while the valves are in place and while the coating material is recirculated through the supply lines.

Description

~ )39~5 This invention relates to the dispensing of coating materials and is particularly concerned with improvemen~s in a dispenser for spraying, pouring, or frothing coating materials.
Dispensing apparatus has been provided here~ofore for applying a variety of coating materials including various plastics which are comprised of relatively rapidly reacting chemical components. Conventional equipment such as the ordinary paint spray gun is not suitable for the application of plastic coatings having chemical components which react rapidly when mixed. While individual components are generally stable, when they are mixed in proper proportions they react quickly to form the completed product and take at least a firm ; set or commence to solidify. Consequently, provision must be made for mixing the components in the proper proportions and immediately dispensing the mixture. Efforts ha~e been made to modify conventional paint spraying guns for dispensing plastic ~` materials of this type. Generally, this has involved pro-viding a mixing chamber within the gun and feeding the ingred-ients through separate supply lines into the mixing chamber in proper proportions so as to produce the desired coating. Much of the apparatus heretofore developed for this purpose has not been satisfactory, generally because adequate provision is not made for ~eeping the apparatus clean so that the control valves and passageways for the ingredients are not clogged and jammed ~y the plastic components becoming set in the same and rendering the apparatus inoperative. One apparatus previously developed and disclosed in my patent ~o. 3,504,855, granted April 7, 1970, has proven highly efficient in use.

~3~49S
However, experience with this and other apparatus of this general character has indicated the desirability of providing a more simplified gun construction which will provide the desired operation with satisfactory efficiency and which may be produced at a lower cost.
It is, therefore, a general object of the invention to provide an apparatus for dispensing coating materials, by spraying, pouring or frothing the material, which is of relatively simple construction and which has adequate provision for maintaining the materials being dispensed at tha proper temperakure, for cleaning the control valves and passageways so that the apparatus may be kept in condition for operation at all times, and which is sufficiently economical to manu-facture so as to compete with more complicated apparatus.
It is a more specific object of the invention to provide a dispenser for coating materials, which includes an improved valve arrangement of relativel~ simple construction - for controlling the flow of the separate elements through the gun so that the valve structures may be kept free of materials which will clog the same and so that they may be readily washed with a solvent, without dismantling the gun, and thereby kept in operative condition.
Another object of the invention is to provide a dis-penser for coating materials having valve structures for controlling the flow of the materials from the supply lines into a mixing chamber, which valve structures are mounted so that they may be readily removed for cleaning and repairing.
The invention as claimed herein is a device for mixing and dispensing coating material which includes a body ~L~39~9~
member having a mixing chamber therein, a discharge nozzle leading therefrom, and laterally spaced parallel bores extending therethrough with passageways leading from an intermediate portion of each bore to the mixing chamber, a flow control valve in the ~orward end of each bore, an adjustably mounted flow selector valve in each bore aligned with the flow control valve, a trigger member having a connection with each of the flow control valves which is operative in one position to open said valves so as to allow passage of coating material :~ 10 through the valves and into the passageways to said mixing chamber, the trigger member being operative in another position to close said flow control valves, each selector valve having an infeed passageway to which an inner supply conduit is attached and a co-operating passageway for return flow of material to which an outer conduit is attached, the outer conduit enclosing the inner conduit, each flow selector valve being disposed in its bore with the innsr end spaced from the irmer end of the associated flow control valve so as to leave a chamber between the valves t each selector valve being adjust-able between a position to connect the infeed passageway withsaid chamber and a position to close the connection with said chamber and to connect the infeed passageway with the return passageway and each flow control valve being disposed in its respective bore so that when in an open position material will flow from said chamber through said control valve.
The said ~low selector valves may have paralle~
axially extending, infeed and return passageways, with generally radially extending outlets at the innermost end, the innermost end being rotatably mounted in a sleeve member fixed in the 3~ S
bore, which sleeve member has axial and circumferential slots arranged to connect the passageways in one rotatable position of the valve through the chamber between the valves and in another rotatable position to close off the connection through said chamber and to connect the infeed and return passageways.
The said control valves may be mounted in said : bores for removal in an axial direction and normally locked in said bores by a locking pin removably positioned in a cross bore spanning the valve bores with portions engagable in a co-operating cross groove in each of said val~es.
The said trigger member may have a connection with the control valves enabling it to be released therefrom and said connection to be disabled so as to release said valves from said bores.
The said body member may have a passageway for connection to a solvent suppl~ line which passageway connects with each of said flow control valves for passage of solvent through said valves into the mixing chamber in one position of the valves and a manually operated solvent valve may be disposed in said passageway enabling the flow of solvent to said control valves to be cut off.
The said flow control valves may each have an axially movable piston member located relative to the associated flow selector valve so that in one position the flow control valve and the flow selector valve are open and material to be mixed flows through both valves to the mixing chamber while in another position both valves are closed to cut off the flow of the material.

- ~L039~5 These and other objects and advantages of the inven~ion will be apparent from a consideration of the spray gun type dispenser which is shown by way of illustra-.
tion in the accompanying drawings wherein:
: Figure 1 is a side elevation showing a spray gun which incorporates the principal features of the invention;
Figure 2 is an elevation of the front or trigger side of the spray gun of Figure l;
Figure 3 is a rear elevation showing the side of the spray gun opposite the trigger;
Figure 4 is a vertical section taken on the line - ~-4 of Figure 2;
Figure 5 is a sectional view taken on the line 5-5 of Figure ~;
Figure 6 is a sectional view taken on the line 6-6 of Figure 4;
Figure 7 is a sectional view taken on the line 7-7 of Figure 4;
Figure 8 is a fragmentary sectional view taken on the line 8-8 of Figure 4, to an enlarged scale, showing the one selector valve in an DON'I position; and Figure 9 is a fragmentary sectional view taken on the same line as Figure 8 but showing the selector valve in "OFF" position.
Referring to the drawings, there is illustrated a spray gun type dispenser which is particularly adapted for the dispensing of a coating material, such as a foam plastic, which may be, for example, constituted by an isocyanate resin and a polyol resin with an appropriate solvent and with air 103~495 pressure employed as a propellant. As illustrated, the gun is designed for a spraying application. With slight adjust-ment or modification it may be used for pouring or frothing the foam material.
The illustrated spray gun comprises a body section or portion of generally circular cross section constituting a head 10 and a handle member 11, respectively. The handle 11 is secured at the top face or end thereof to the head member 10 i~ a suitable manner. The head 10 has a nozzle 12 joined by a connector member or coupling 13 with the head 10 and telescoping a portion of a tubular section 14 forming a mixing chamber 15. The tubular section 14 is butted against the impingement chamber 1~ which is seated in the recess 16 con-stituting the inner or forward end of a bore 17 extending through the top portion of the head 10. ~he coupling 13 has its end connected in threaded engagement in the forward end o~ the bore or recess 16. The bore 17 has an enlarged diameter rear end portion in which there is mo~nted an air valve assembly 20 by means of an externally threaded bushing 21 engaging an internally threaded section at the rear entrance to t~e bore 17.
The air valve 20, which may control any suitable gaseous propellant material, comprises a barrel or spool member 22 which is axially slidable in an axial bore 23 opening at the rear end of a housing or valve body forming member 24 which constitutes an air chamber. The body member 24 has a forward end portion 25 of reduced cross section which extends into the rear portion of the tubular section or impingement chamber 18. The cross section of the 3~4~5 bore 23 is progressively reduced in steps toward a forward end portion which acts as a no~zle wi~h an elongated passage-way 26 of relatively small cross section. The valve barrel or spool 22 has an axial air passageway 27 with a laterally extending passageway at the forward end which is axially spaced from the tapered inner end portion 28. The barrel or spool end 28 is adapted to engage a seat forming shoulder 30 in the bore 23 in closing the valve. A valve operating nut 32 has an internal shoulder at one end which rotatably engages a fixed abutment shoulder on the bushing 21 and at the other end is in threaded engagement with a head portion 33 on the axially slidable valve spool or barrel 22 so as to ena~le the valve to be opened and closed by rotating the same. The valve spool is prevented from rotating about its a~is by pin 34 which extends into a co-operating axial slot in the spool outer wall. The end 25 of the valve housing 24 terminates short of a pair of radial apertures or port form-ing openings 35 and 35' ~Figure 6~ in the wall of impinge-ment c~amber 18 (Pigures 4 and 6) through which the resins enter the mixing chamber 15 by means of passageways 36 and 36' from trigger operated control valve assemblies 40 and 40'.
The materials which are to be mixed to form the desired coating are supplied to the gun through infeed suppl~ conduits 42 and 42' (Figures 4 and 7) which are connected by means of suitable couplings or nipples 43 and 43' in threaded bores at the rear ends of infeed passageways 44 and 44' which extend axially in selector valve assemblies 45 and 45'. The selector valve assemblies are mounted in parallel bores 46 and 46' which, in transverse section, are ~\
3 (~39g1~ ~
in a triangular forming arrangement with the upper parallel bore 17 in the gun body or head 10 in which the air valve assembly 20 is mounted. The inner material infeed conduits 42 and 42' have associated outer return conduit members 47 and 47' which have an internal diameter larger than the external diameter of the inner conduits 42 and 42' and which encase or surround the latter. The outer conduits 47 and 47' are connected by nipple and adapter assemblies 48 and 48' to the outer ends of the body portions 50 and 50' of the flow selector members or valves 45 and 45' to which the inner conduits 42 and 42' are coupled so as to be in communication with return flow passageways 52 and 52' which are generally parallel with the passageways 44 and 44', respectively, and which extend to generally radial or laterally directed open-ings near the forward ends of the ~alve body members 50 and 50'. The valve body members 50 and 50' have tapered forward end portions which are seated in sleeve members 53 and 53'.
Sleeve members 53 and 53' are in turn non-rotatably seated in the parallel bores 46 and 46'. The rearward ends of the sleeve members 53 and 53' are internally threaded for engagement by the externally threaded end portion of nuts 54 and 54' which hold the valve bodies in the sleeves53 and 53' by means of engagement with an external shoulder thereon while permitting rotation of the body members 50 and 50' about their respective longitudinal axes. Hexagon rings 55 and 55' are secured on the rearward ends of body members 50 and 50' for manual rotation of the assemblies. The coupled hose or material feeding assemblies turn with the ~alve body members when the selector valves are rotated.

9~13139~495 As shown in Fi~ures 4 and 7, the forward ends of the valve bodies 50 and 50' are spaced from the forward ends of bores 46 and 46' and the sleeves 53 and 53' have axial slots 56 and 56' (Figures 4, 8 and 9), which, as shown in Figure 4, allow inflowing fluids to pass from the passageways 44 and 44' into the small chamber or recess 57 formed at the end of the valve body. Axially extending passageways 58 and 58' at the ends of the valve bodies connect wi~h generally radial passage-ways 60 and 60' which open into one end of circumferential slots 62 and 62' in the sleeves 53 and 53'. The slots 62 and 62' extend for approximately one quarter of the circumference so that in the "0~" position of the valve bodies 50 and 50' (Figures 4, 7 and 8) the fluid may flow through the passage-ways 58 and 58', the slots 62 and 62' and into the passage-ways 52 and 52' for return through the outer conduits.
Rotation of the valve members 50 and 50' is limited to approxi-mately 90 by a set screw 64 which has an end extending into a co-operating groove in the outer wall of each of the valve boaies 50 and 50'. When the valve bodies 50 and 50' are rotated to the alternate "OFF" position (Figure 9) the fluid flows directly from the passageways 44 and 44' into t~e slots 62 and 62' and from there into the return passageways 52 and 52'. While in the "0~" position the passageways 58 and 58' may be closed by operation of control valve assemblies 40 and 40' (Figures 4 and 7) through movement of the trigger member 65.
The flow control valve assemblies 40 and 40' (Figures 2 and 4 to 7) are mounted in a recess 67 at the foxward end of the body or head 10 with rearward end portions _g_ 49~i seated in parallel bores 68 and 68' w~ich are axially aligned with the bores ~6 and 46', respectively, in which the selector valve assemblies 45 and 45' are mounted. The bores 68 and 68' are of smaller diameter than the bores 46 and 46'. The control valve assemblies 40 and 40' comprise cylindrical valve bodies or housing members 70 and 70' w-nich are seated in fixed position in the bores 68 and 68', with suitable external seal forming rings, and piston or spool members 72 and 72' which are axially slidable in the body members 70 and 70'. The spool members 72 and 72' each have an inner head portion 73 and 73' of enlarged cross section with a tapered forward face portion 74 and 74' extending to a section 75 and 75' of substantially reduced cross section as to provide a relatively small cylindrical chamber 76 and 76' at the end of the valve member 70 and 70' and for seating at the head portion 73 and 73' on a complementary tapered edge at the end of the valve body thereby to close the inner end of the chamber 76 and 76'. The valve housings 70 and 70' have portions 77 and 77' of enlarged diameter at the forward or outer ends which are encased in the inner end portions of tubular sleeve members 78 and 78' in the forward ends of which compression springs 80 and 80' are housed. rrhe springs 80 and 80' surround the portions 82 and 82' of the valve spools 72 and 72' with one of their ends seated on the ends of the valve housings 70 and 70' and the other ends abutting the inner faces of the head portions of caps 83 and 83' which are secured in the ends of the spools 72 and 72' so as to normally hold the valve end members 73 and 73' in valve closing position and permitting the ends of the ~L~3~95 chambers 76 and 76' to be opened hy axial sliding movement of the spools 72 and 72' so as to permit passage of spray material from the chambers 57 and 57' into the chambers 76 and 76' and through openings 84 and 8~' in the walls of the valve housings 70 and 70' which constitute openings into the passageways 36 and 36' leading to the mixing chamber 15. These walls have diametrically opposite openings 85 and 85l (Figures 4 and 6) for entrance of solvent material from a push type solvent flushing valve assembly 86 which is mounted in a cross bore 87 lmmediately below the two control valve housing members 70 and 70' and which is best shown in Figure 6.
The housings 70 and 70' of the valve assemblies 40 and 40' are held against movement in an axial direction by a removably mounted locking pin 90 which is slidable in a transverse bore 92 in the body 10. The bore 92 is located relative to the recess 67 as shown in Figure 5 so that full diameter portions 93 and 93' of the locking pin 90 will extend into the recess 67 when the pin 90 is fully inserted into the bore 92 and will engag~ in transverse grooves 94 and 94' in the valve housings 78 and 78' and body members 70 and 70'. The locking pin 90 is provided with axially spaced full diameter portions 93 and 93' permitting partial axial movement for unlocking the valve assemblies 40 and 40' and enabling their removal as units ~or replacement or repair.
The locking pin 90 is held in the bore 92 by a spring plunger screw 95 (Figure 4).
The control valve assemblies 40 and 40' are operated by pivotal movement of the trigger member 65. The trigger member 65 carries a cross pin or cross bar 96 ~C)39~ BS
tFigures 2, 4 and 7) which has its opposite ends extending through axially extending slots 97 and 97' in oppositely disposed wall portions of the sleeve members 78 and 78' of the control valve housing and the valve bodies 70 and 70' and is pivoted to the valve spool or core members 72 and 72'. The trigger member 65 has a top end extension 98 which extends into a downwardly opening recess 100 in the top wall of the recess 67 and forms a loose pivot point for the trigger member. The cross pin 96 sits in an upwardly opening cross slot 101 on the trigger and is removably held therein by a spring plunger screw. The compression springs 80 and 80' normally hold the trigger member 65 pivoted to the inoperative position. The control valve assemblies are opened for resin feed by pressing the trigger handle 65 toward the gun handle 11 which moves the valve spool heads or end portions 73 and 73' inwardly into engagement with the forward ends of the selector valve members 50 and 50' which closes the passageways 58 and 58' and allows the resins to flow from chambers 57 and 57' through the valve assemblies 40 and 40'. The rearward movement of the valve spools 72 and 72' closes the valve openings 85 and 85' and prevents flow of solvent regardless of position of solvent flush valve 86.
The solvent flush valve 86 (Figure 6) is a push type which comprises an elongated cylindrical body or housing member 105 of a size to fit in the cross bore 87 and a core forming spool member 106 which is slidable in the body or housing member 105. The housing or body member 105 has external grooves 107 and 108 forming passageways connecting with the openings 85 and 85' in the control valve bodies 70 and ~03~495 70'. A cross bore 110 in the valve housing 105 connects the grooves 107 and 108 with the inside of the housing 105 at a point where t~e connection is closed by the valve head portion 112 of the spool in one position of the latter and opened in another position of the latter. The valve is normally held close~ by a compression spring 113 seated at one end against the spool head 112 and at the other end against a set screw 114 in the end of the valve body 105. The(valve spool 106 has a stem portion with a threaded end on which a button is fastened for manual operation of the spool. Solvent is supplied to the valve 86 through a passageway 115 (Figures 3 and 4~ to which there is suitably connected a solvent supply line. The passageway 115 connects with an opening 116 into the interior of the valve housing 105 at the same point as the outflow ports formed by the bore 110.
In using the illustrated form of the device in a typical spray coating operation employing a ~oam plastic, the kwo resin components which are to be mixed and discharged through the nozzle 12 by an air propellant are fed from a supply tank through the conduits 42 and 42' with the material being heaked to the proper temperature required for the desired mixing. The manually operated selector valves 45 and 45' may be adjusted to recirculate the resin components through the supply tan~s without passage of the resin components through the control valves 40 and 40' as shown in Figures 4 and 8 of the drawings. When it is desired to operate the gun for spraying or dispensing the mixed resins the selector valves 45 and 45' are first rotated to the position shown in Figures 4 and 8. With the trigger 65 in the normal 9L~3~4~S
inoperative position shown in solid lines in Figure 4, the valve assemblies 40 and 40' remain in the position shown in Figures 4 and 7 and the resin components are recirculated through the selector valves 45 and 45' as shown. This is the normal "OFF" position of the control valves 40 and 40'.
In this position of the valves 40 and 40' the solvent line is opened for passage of solvent through the valves and into the mixing chamber 15 to flush out the same upon operation of the solvent control valve ~6.
When the trigger 65 is swung toward the handle 11 to the fully "ON" position the valves 40 and 40' are in the position indicated by dotted line in Figure 7, and the valve ends are closed on the ends of the selector valves 45 and 45' so that the resin materials flow through the selector valves 45 and 45' and through the control valves 40 and 40' ~o the mixing chamber 15. In this position of the valves 40 and 40' the solvent passageways 85 and 85' are blocked off by the valve spools 72 and 72'.
The selector valves 45 and 45' may be rotated 90 to the position shown in Figure 9 which will prevent the -flow of resin materials into the chambers 57 and 57' and allow return of the resin materials through the passageways 52 and 52', while valves 40 and 40' can be opened sufficiently to allow the solvent flush valve 86 to be operated to flush out the passageways and the mixing chamber. The air or other propellant control valve 20 can be manually opened and closed as desired.
The valve assemblies 40 and 40' are both held in the bores 68 and 68' by the loc~ing pin 90. The trigger 65 ~0;~49S
may be released from the pin 96 and removed, whereupon thevalve assemblies 40 and 40' may be readily removed, ~y with-drawing the locking pin 90, as complete units from the bores 68 and 68' for cleaning or replacement of parts. The selector valves 45 and 45' are, of course, adjusted to the position shown in Figure 9 when the control valve units or assemblies 40 and 40' are to be removed so as to prevent passage of the resin components into the bores 68 and 68' and enabling the same to be recirculated through the supply tanks.
While the apparatus has been illustrated and des-cribed as a spray gun type dispenser, it is not intended that its use be limited to a spraying operation. It may also be used for pouring or frothing operations. For a pouring operation it is necessary to remove the nozzle and replace the same with a plain spout forming piece of pipe or hose (not shown) which may contain a motor driven agitator for the purpose of mixing the plastic components. For the frothing operation a different mixing head i5 employed havin~ a spiral coil for dispensing the foam material.
~hile particular materials and specific details of construction have been referred to in describing the form of the apparatus illustrated it will be understood that ot~er materials and e~uivalent structural details may be employed within the spirit of the in~ention.

Claims (14)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A device for mixing and dispensing coating material which comprises a body member, means forming a mixing chamber in the body member and a discharge nozzle leading therefrom, said body member having parallel bores extending therethrough, passageways leading from one end of each bore to said mixing chamber, a flow control valve mounted in said one end of each bore, a flow selector valve adjustably mounted in each said bore in alignment with the flow control valve therein, a pivotally mounted trigger member having a connection with each of said flow control valves and operative in one position thereof to open said control valves so as to allow passage of coating through said passageways to said mixing chamber and operative in another position to close said flow control valves, each said flow selector valve having an axially extending infeed passageway to which an inner supply conduit is attached and a parallel passageway for return flow of material to which an outer conduit is connected which outer conduit encloses said inner supply conduit, each said flow selector valve being disposed in its respective bore so as to provide a relatively small chamber between the innermost end thereof and the confronting innermost end of the associated flow control valve, each said selector valve being formed so that it is adjustable to a position to connect the infeed passageway with said chamber and also adjustable to a position to close the connection with said chamber and to connect the infeed passageway with the return passageway and each flow control valve being formed and disposed in its respective bore so that when said valve is in an open position material will flow from said chamber through said control valve.

2. A device for mixing and dispensing coating material as set forth in Claim 1 wherein each of said flow selector valves has parallel, axially extending, infeed and return passageways with generally radially extending outlets at the innermost end thereof and said innermost end is rotatably mounted in a sleeve member fixed in the bore in which the selector valve is mounted, which sleeve member has axial and circumferential slots arranged to connect said passageways in one rotatable position of said selector valve through said chamber between said selector valve and the associated flow control valve and in another rotatable position thereof to close off the connection through said chamber while maintaining a connection between said infeed and return passageways.

3. A device for mixing and dispensing coating material as set forth in Claim 1 wherein each of said flow selector valves has parallel, axially extending infeed and return passageways which open radially at the innermost end thereof with the openings spaced circumferentially of each other and wherein each said valve is rotatably mounted at its innermost end in a fixed sleeve forming member, said sleeve forming member having an axially extending slot positioned to connect said infeed passageway with the chamber between said selector valve and the associated flow control valve in one position of the flow control valve and said sleeve member having a circumferential slot on its inner face connecting said infeed and return passageways in another position of said flow selector valve.

4. An apparatus for mixing and dispensing a coating material which apparatus comprises a body member having a bore in one end of which there is a mixing chamber and in the other end of which there is mounted a valve for controlling the flow of propellant material from a connecting supply line, a pair of parallel bores in said body member having flow control valve assemblies seated in one end thereof and flow selector valves adjustably seated in the opposite end thereof, passage-ways connecting said pair of bores with said mixing chamber, said flow control valve assemblies having axially movable members which are operable to open and close the passageways leading to said mixing chamber, said slow selector valves having axially extending, parallel passageways for connection to material supply lines which comprise inner infeed and outer return conduits in telescoping relation, means associated with said flow selector valve assemblies for selectively connecting said infeed passageways with the passageways leading to the mixing chamber upon opening of said flow control valves and for connecting said infeed passageways with the associated return passageways while closing off the connection with said mixing chamber,said flow control valve assemblies being operable by a readily removable trigger mechanism and said flow control valve assemblies being removable as units from said bores for cleaning and repair and being locked in said bores by a lock pin removably seated in a cross bore beneath said valve assemblies which lock pin has portions extending into recesses in the valve assemblies when said pin is seated in said bore.

5. A device for mixing and dispensing coating material which comprises a body member, means forming a mixing chamber in the body member and a discharge nozzle leading therefrom, said body member having laterally spaced, parallel bores extending therethrough, passageways leading from an intermediate portion of each bore to said mixing chamber, a flow control valve mounted in the forward end of each bore, a flow selector valve adjustably mounted in each said bore in alignment with the flow control valve therein, a valve operating trigger member having a connection with each of said flow control valves and operative in one position thereof to open said control valves so as to allow passage of coating material through said control valves and into the passageways leading to said mixing chamber, and said trigger member being operative in another position to close said flow control valves, each said flow selector valve having an infeed passageway to which an inner supply conduit is attached and a co-operating passage-way for return flow of material to which an outer conduit is connected, said outer return conduit enclosing said inner supply conduit, each said flow selector valve being disposed in its respective bore with the inner end spaced from the inner end of the associated flow control valve so as to leave a chamber between said valves, each said selector valve being formed so that it is adjustable to a position to connect the infeed passageway with s aid chamber and also adjustable to a position to close the connection with said chamber and to connect the infeed passageway with the return passageway and each flow control valve being formed and disposed in its respective bore so that when said valve is in an open position material will flow from said chamber through said control valve.

6. A device for mixing and dispensing coating material as set forth in Claim 5 wherein each of said flow selector valves has parallel, axially extending infeed and return passageways with generally radially extending outlets at the innermost end thereof and wherein said innermost end is rotatably mounted in a sleeve member fixed in the bore, which sleeve member has axial and circumferential slots arranged to connect said passageways in one rotatable position of said selector valve through said chamber between said selector and control valves and in another rotatable position thereof to close off the connection through said chamber and to connect said infeed and return passageways.

7. A device for mixing and dispensing coating material as set forth in Claim 5 wherein each of said flow selector valves has parallel, axially extending infeed and return passageways which open radially at the innermost end thereof with the openings spaced circumferentially approxi-mately 90° relative to each other and wherein each said valve is mounted at its innermost end in a fixed sleeve forming member for 90° rotation therein, said sleeve forming member having an axially extending slot positioned to connect said infeed passageway with the chamber between said valves in one position of the flow control valve and said sleeve member having a circumferential slot on its inner face con-necting said infeed and return passageways in another position of said flow selector valve.

8. A device for mixing and dispensing coating material as set forth in Claim 5 wherein said flow control valves are mounted in said bores for removal from said bores in an axial direction and said valves are normally locked in said bores by a locking pin which is removably positioned in a cross bore spanning said valve bores and which has portions engageable in a co-operating cross groove in each of said valves

9. A device for mixing and dispensing coating material as set forth in Claim 8 wherein said trigger member has a connection with said control valves which enables said trigger member to be released from said connection and said connection disabled so as to release said valves for removal from said bores.

10. A device for mixing and dispensing coating material as set forth in Claim 5 wherein said body member has a passageway for connection to a solvent supply line which passageway connects with each of said flow control valves for passage of solvent through said flow control valves and into said mixing chamber in one position of said flow control valves.

11. A device for mixing and dispensing coating material as set forth in Claim 10 wherein a manually operated solvent valve is disposed in said solvent passageway which enables the flow of solvent to said control valves to be cut off.

12. A device for mixing and dispensing coating material as set forth in Claim 10 wherein a transverse bore spans the bores in which the flow control valves are housed, connecting solvent passageways between said transverse bore and said flow control valves and a valve in said transverse bore controlling the flow of solvent.

13. A device for mixing and dispensing coating material as set forth in Claim 5 wherein said flow control valves each have an axially movable piston member operable to open and close the valve and said trigger member has an end portion which is seated in pivoting relation in a recess in said body member and said trigger member carries a cross rod having opposite ends engaging said valve piston members for axially moving said piston members when said trigger member is pivoted.

14. A device for mixing and dispensing coating material as set forth in Claim 5 wherein said flow control valves each have an axially movable piston member which is so constructed and located relative to the associated flow selector valve that in one position thereof the flow control valve and the flow selector valve are open and material to be mixed flows through both valves to the mixing chamber while in another position of said piston member both valves are closed so as to cuttoff the flow of material.