BACKGROUND  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to a device and method for mixing a water-dilutable, water-free paint concentrate with water at the time of spraying onto a paintable surface.  
           [0003]    2. Prior Art  
           [0004]    A water-dilutable paint such as latex and water-dilutable acrylic paint comprises primarily coloring pigments in a resin (“Paint” and “stain” are used interchangeably and meant to include all manner of paints, stains and all other liquid compounds applied to color, protect, or cover a surface with a film or absorbent). Several other components can be added such as wetting agents and antifoams, and extenders. These components are mixed in water to a viscosity suitable for application by spraying or by brush or roller. Paint components mixed in water decompose in time and also tend to settle to the bottom. To counter this decomposition and settling, a paint stabilizer is also added. The stabilizer and other additives dilute the paint.  
           [0005]    Water-dilutable paint typically comprises a high proportion of water and a low proportion of paint concentrate. The mixed paint is packaged, transported, stored, and applied with this high proportion of water, increasing cost and inconvenience of dealing with weight and volume increased by the water over the paint ingredients. It would be advantageous to maintain the paint ingredients unmixed from the water until the paint is applied. Water is generally available for mixing with these paint ingredients at the place of application of the paint. This would eliminate the need for stabilizers and greatly reduce the volume and weight of the paint to its essential elements.  
           [0006]    It is the primary object of the present invention, therefore, to have a paint concentrate without water that is first mixed with water at the time of spray delivery of the paint to a paintable surface.  
         SUMMARY  
         [0007]    This object is achieved in a water-tight unpressurized reservoir of constant volume containing the water-dilutable paint concentrate without water and a head typically secured to the reservoir, although conceivably the head can be detached with a tube between them. The head comprises a mixing chamber, a spray nozzle that directs and atomizes the paint composition, and a conduit attachment to which a water conduit is attached, typically a household garden hose. In operation, water typically under waterline pressure is delivered through the garden hose to the mixing chamber and out the spray nozzle. Concentrate from the reservoir is siphoned or otherwise extracted from the reservoir into the mixing chamber, such as by gravity feed, where it mixes with water passing through in an aqueous solution approximately one part paint/stain solids to three to twenty parts water. A valve regulates flow from the reservoir.  
           [0008]    Typically, the valve also regulates flow of water in a three-way valve, including a fully closed position where no water or concentrate flows, an opened position where water and concentrate flow for mixing and delivery through the nozzle suitable for spray application, and a water flow position, where the concentrate is closed but water continues to flow for flushing the mixing chamber and nozzle for cleaning purposes. With water flowing unmixed through the spray nozzle, the directed flow is advantageous for clean up, for example, of overspray until the paint is dry. A surface inadvertently painted can usually be washed clean of sprayed paint with clear water from the nozzle during the first ten minutes after application. This facilitates not only the clean up but also the painting process. It becomes more efficacious to not even cover or otherwise prepare adjoining surfaces and ignore overspray during the painting process. Then using the clear water pass through mode of operation, water is directed onto the overspray area which washes it clean. Clear water that might mist or slightly splatter onto the painted area is unaffected by the water. If one chooses, a board may be briefly held between the painted area and the overspray area in the near vicinity of clear water clean up.  
           [0009]    For purposes within, “waterless” or “water free” or the like is meant to mean water restricted and without water added but recognizing that paint ingredients may naturally have water within a compound. “Resin” is meant to include all water-dilutable resins forming a film when applied to a paintable surface. Water soluble resins typically contain carboxyl groups that make them water-dilutable. They can be any of many commercially available resins. Once specific example is known commercially as NeoCryl XK-90. “Pigment” is meant to include any and all inorganic and organic compounds and metallic powders employed to provide cover, color effect and cover. Two well-known commercially-available pigments are SGS yellow iron oxide 115 (yellow iron oxide) and SGS red iron oxide 417 (red iron oxide). The resin and pigments as the primary concentrate ingredients are combined in a paint or stain composition, meant to include all forms of combination of paint ingredients, such as mixtures, solutions, emulsions, dispersions and suspensions. Water dilutable is also meant to include water soluble and any of these combinations of ingredients with water. Other additives, meant to include all other ingredients such as stabilizers, antifoamants, anticratering additives, wetting agents for dispersion of the pigment, binders and the like, are added to render the concentrate applicable to a paintable surface.  
           [0010]    Table 1 following represents a typical 1-gallon formula of paint concentrate.  
                                           TABLE 1                           Concentrate Formula, 1 Gallon                Ingredient   Lbs./Gal                            Propylene Glycol   0.2           Nuosept 95   0.008           Nuocide 960   0.008           AMP-95   0.01           Surfynol CT-111   0.016           Tinuvin 1130   0.04           Lactimon WS   0.047           Attagel 50   0.05           BYK 022   0.006           BYK 024   0.006           Minex 4   0.6           SGS YO 115   4.634           SGS RO 417   0.724           NeoCryl XK-90   3.092           NeoCryl A-639   2.293           NeoRez R-9649   0.097           Texanol   0.135           Solvent EB   0.135           Bentolite WH   0.013                      
 
           [0011]    These formula ingredients are understood as follows:  
           [0012]    a. Propylene Glycol (dihydric alcohol) is used as an esterifying agent (a process involving the interaction of a compound possessing a hydroxyl group with an acid, with the elimination of water. This ingredient is used to help the stain form a film and it also acts as an anti-freeze. It is also used as a wet-edge additive.  
           [0013]    b. Nuosept 95 (formaldehyde, bicyclic oxazolidines) is a preservative used to prevent the stain from growing bacteria and fungus while it is in storage in its container.  
           [0014]    c. Nuocide 960 (chlorothalinil) is a fungicide and algaecide used to prevent mold and mildew from growing on the surface of the stain or paint after it is applied to a paintable surface such as a house or a fence. Although acrylic stains are not prone to attract mold and mildew growth in dry climates, this ingredient helps prevent the normal occurrence of mold and mildew that might occur in damp climates, such as the Pacific Northwest.  
           [0015]    d. Amp 95 (2-amino-2-methyl-1-propanol) is used as a pigment dispersant or stabilizer that increases the stability of a suspension of pigments in the stain and also as a pH modifier. Without a dispersant the pigments tend to settle to the bottom of a composition and water based coatings need to have a certain pH for the paint/stain to form a film on the paintable surface.  
           [0016]    e. Surfynol CT-111 (alkoxylated acetylenic diol) is used as a surfactant. Most pigments in the dry state contain bound agglomerates of primary particles. A primary particle is one of optimum size of pigment structure that achieves the best color development. In order to disperse these primary particles in water, they are subjected to deagglomeration to break up the agglomerates, wetting to disperse the pigment from the resin surface, and stabilization to maintain the pigment throughout the resin. This additive reduces surface tension and improves wetting, thereby helping to disperse pigments and inhibit foaming or emulsifying.  
           [0017]    f. Tinuvin 1130 (hydroxyphenyl benzotriazole) is a liquid ultra-violet radiation absorber used as a light stabilizer to protect the substrate from the harmful effects of the sun.  
           [0018]    g. Lactimon WS (a solution of a partially neutralized alkyl-ammonium salt of a polycarboxylic acid polymer and a polydimethylsiloxane) used as a wetting and dispersing deflocculating additive to improve pigment wetting and to stabilize the pigment dispersion preventing flooding and floating and improving gloss. It contains a polysiloxane copolymer which helps to prevent pigment separation and in particular helps to counteract formation of Benard cells and pigment striations.  
           [0019]    h. Attagel 50 (attapulgite crude) is a colloidal, inorganic mineral thickener that is essentially inert and non-swelling in aqueous applications. When dispersed in water, it displays unique thixotropic (gelling) properties that promotes anti-settling and drip and sag control.  
           [0020]    i. BYK 022 (composition of hydrophobic solids, emulsifiers and foam destroying polysiloxanes in polyglycol) is a silicone defoamer for aqueous coatings.  
           [0021]    j. BYK 024 (emulsion of hydrophobic solids, emulsifying agents and foam destroying polysiloxanes) is a silicone defoamer for aqueous coatings. T  
           [0022]    k. Minex 4 (nepheline syenite) is used as an extender and a filler. It is an achromatic pigment of low refractive index in a range of 1.5 to 1.6. Consequently, it does not contribute significantly to the hiding power of the paint/stain. It is used to reduce cost, achieve durability, and alter appearance (e.g., decrease in gloss).  
           [0023]    l. SGS Yellow Iron Oxide 115 (SGS YO; yellow iron oxide) is a yellow pigment dispersion. These are finely ground synthetic insoluble dispersed particles which, when dispersed in a liquid vehicle to make paint, also enhances paint-opacity, hardness, durability, and corrosion resistance. As great ultraviolet absorbent colorants, oxide pigments are also are one of the best ingredients to protect a surface from damaging effects of the sun.  
           [0024]    m. SGS Red Iron Oxide 417 (red iron oxide) is a red pigment dispersion. As with SGS YO, these are also finely ground synthetic insoluble dispersed particles which, when dispersed in a liquid vehicle to make paint, also enhances paint-opacity, hardness, durability, and corrosion resistance and are one of the best ingredients to protect a surface from damaging effects of the sun.  
           [0025]    n. Neocryl XK-90 (acrylic copolymer emulsion) as a resin holds the pigments to the paintable surface. It is a 100% acrylic emulsion polymer designed for exterior paints and stains. It provides excellent color development and early block resistance and outstanding wet adhesion to aged and chalked alkyds. Its unique small particle morphology gives hard durable stains with cosolvent demands as low as 3.5% on resin solids. Blocking is the undesirable sticking together of two painted surfaces when pressed together under normal conditions or under specified conditions of temperature, pressure and relative humidity. Without block resistance, for example, the stained gate on a fence may stick shut even after the stain has already dried  
           [0026]    o. Neocryl A-639 (acrylic polymer) also is an acrylic copolymer resin that holds the pigments to the paintable surface that is used to formulate pigmented industrial coatings for wood substrates. It exhibits excellent chemical resistance, hardness, and good block resistance.  
           [0027]    p. NeoRez R-9649 (water-borne urethane) is a coating vehicle that contains a polyisocyanate monomer reacted to yield polymers containing a combination of urethane linkages, active isocyanate groups or polyisocyante monomers. It exhibits very low coeffecient of friction and excellent rub resistance. It also exhibits excellent water and stain resistance.  
           [0028]    q. Texanol (ester alcohol: 2,2,4-Trimethyl-1,3-pentanediol Monoisobutyrate) is a slow evaporating, water-insoluble coalescing aid for water-borne paints. It provides good scrub resistance, color development, and package stability. It is an excellent coalescing aid for emulsion polymers and has excellent hydrolytic stability, allowing it to be used with a wide variety of latex emulsions including high pH acrylics. When added to emulsion paint, it is absorbed by the emulsions polymeric particles, softening them and causing complete fusion when the paint film dries. Since Texanol is insoluble in water and therefore is not in a water phase, applying the paint over a porous substrate does not result in reduced coalescing efficiency because it is not absorbed by the substrate along with the water.  
           [0029]    r. Solvent EB (ethylene glycol monobutyl ether) is necessary for the paint/stain to form a film. It is a colorless liquid soluble in alcohol and water having a high dilution ratio with petroleum hydrocarbons. It oxides slowly when exposed to air, particularly at elevated temperatures.  
           [0030]    s. Bentolite WH (bentolite) swells in water and is used as a thickening agent. It is a very fine-grained clay derived from volcanic ash and consisting largely of montmorillonite mineral. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0031]    [0031]FIG. 1 is a perspective view of the apparatus of the present invention.  
         [0032]    [0032]FIG. 2 cut-away side view of the apparatus of FIG. 1 shown with paint concentrate inside and a water hose connected.  
         [0033]    [0033]FIG. 3 is a top plan view of the apparatus of FIG. 1 shown with a valve slide outside but aligned longitudinally.  
         [0034]    [0034]FIG. 4 is a front end view of the apparatus of FIG. 1.  
         [0035]    [0035]FIG. 5 is a side plan view of the apparatus of FIG. 1.  
         [0036]    [0036]FIG. 6 is a top view of the valve stem divider. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0037]    The present apparatus for spraying water dilutable paint is adapted to mix a paint concentrate  100  with water  102  flowing through the apparatus  10  to form a paint suitable for application to a paintable surface. The apparatus  10  mixes the paint concentrate  100  in a mixing chamber  15  within the apparatus  10  only immediately prior to spraying the mixed paint to that paintable surface. Until the concentrate  100  is mixed with water  102 , it is in a concentration unsuitable for application to a paintable surface. Typically, the concentrate  100  comprises between fifty and fifty-seven percent solids (nonvolatile matter in a stain or paint composition that remains after drying to constitute a dry film). Typically, the resin is at least 45% and the pigment is at least 44% of the concentrate total weight. After mixing with water, the composition comprises approximately 3 to 20 parts of water by volume for each part concentrate.  
         [0038]    The apparatus comprises a reservoir  20  in which the water-dilutable paint concentrate  100  is contained until mixed with water  102  at the time of application. The paint concentrate includes a paint resin and a paint pigment at high solids (50-70%) without water as its major ingredients by weight. A valve  30  in fluid communication with the reservoir  20  prevents water from entering the reservoir  30 , which would contaminate the concentrate  100 , thus maintaining the concentrate  100  substantially without water. The valve  30  includes a first, or open, position that provides fluid communication between the reservoir  20  and the mixing chamber, a second, or closed, position that blocks fluid combination between the reservoir  20  and the mixing chamber  15 , and a third position providing fluid communication between a water attachment fixture  40  and the mixing chamber  15  while blocking fluid communication between the mixing chamber  15  and the reservoir  20 .  
         [0039]    The mixing chamber  15  is in fluid communication with the valve  30  with the valve  30  between the reservoir  20  and the mixing chamber  15 . The valve  30  thus regulates flow of concentrate  100  from the reservoir  20  to the mixing chamber  15 .  
         [0040]    Pressurized water  102  is provided from an external conduit  42 , typically a garden hose under waterline pressure, which is attached to the mixing chamber  15  at the water attachment fixture  40 , feeding water  102  into the and through the mixing chamber  15 . A spray nozzle  34 , through which said paint concentrate is sprayed, typical in paint spray guns, in fluid communication with the mixing chamber  15 , receives the mixed paint composition from the mixing chamber  15  which is then discharged through the nozzle  34 .  
         [0041]    Thus, paint concentrate  100  flows from the reservoir  20  through the valve  30  and into the mixing chamber  15  when the valve is in a first, or open, position. The concentrate  100  then mixes with water  102  fed from the attached water conduit  42  under pressure forming a water dilutable paint composition. Flow of the concentrate  100  is such as to yield a composition of a suitable concentration capable of application to a paintable surface to form a dried coating of paint.  
         [0042]    Typically, the mixing chamber  15 , valve  30 , water attachment fixture  40  and spray nozzle  34  comprise a spray head  50  that attaches to the reservoir  20 . The water attachment fixture  40  is at a spray head first end  51  and the spray nozzle  34  at a spray head second end  52  with a straight passageway  53  between them through which water  102  passes. A valve stem  62  in a head vertical bore  60  has a channel divider  61  that divides the straight passageway from the water attachment fixture  40  into first and second passageways  53   a  and  53   b  ending in first and second spray nozzles  34   a  and  34   b.  For mixture with paint concentrate  100 , the valve stem  62  is turned to direct water  102  into first passageway  53   a.  For water passage through the head and out the nozzle  34  without mixture with concentrate  100 , the valve stem  62  is turned to direct water  102  into second passageway  53   b  and out second nozzle  34   b.    
         [0043]    A reservoir attachment fixture  54  is adapted to attach to a matching reservoir port  55 . A valve tube  56  provides fluid communication between the first passageway  53   a  and the reservoir attachment fixture  54 . A reservoir conduit  21  extending into the reservoir  20  attaches to the reservoir attachment fixture  54  effectively extending the valve tube  56  into the reservoir  20 . As concentrate  100  is then drawn from the reservoir  20  through the valve tube  56  into the passageway  53 , it mixes with water passing through the first passageway  53   a  between the valve tube  56  and the nozzle, that portion of the first passageway  53   a  comprising the mixing chamber  15 .  
         [0044]    A valve slide  57  with a vertical valve hole  58  therethrough slides transverse to the valve tube  56  between the first passageway  53   a  and the reservoir attachment fixture  54  between open and closed positions in a head channel  59  that runs from the valve tube  56  to the head vertical bore  60  that intersects the passageway  53 . In the open position the hole  58  is in alignment with the valve tube  56 . In other valve positions, the valve slide  57  slides out of alignment of the valve hole  58  with the valve tube  56 , including the second and third, or closed and through positions described above. The valve slide  57  includes a rack  61  at its end intersecting the head vertical bore  60 . Valve stem  62  fits snugly in the head vertical bore  60  and includes a pinion  63  on its bottom end  64  that meshes with the valve slide rack  61 . A valve handle  65  fits on a valve stem top end  66  to turn the valve stem  62 , adapted such that as the valve handle  65  turns the valve stem  62 , the valve pinion  63  engages the valve slide rack  61  causing the valve slide  57  to slide in the channel  59  therein bringing the valve hole  58  into and out of alignment with the valve tube  56 .  
         [0045]    The simplicity of design lends itself to low-cost production with disposable capability. The design reduces to a container with an expensive spray head. A concentrate must be marketed in some container anyway. The addition of a low cost spray head is the only additional cost. Compared with the cost of a spray gun and larger containers that would otherwise be required with premixed paint/stain, the spray head becomes the less costly alternative. With no intent to clean the apparatus, but instead throw it away after first and only use rather than refilling the reservoir, a simplified two-way valve opening and closing the reservoir is all that is required. The water from the water conduit can be opened and closed with the same valve positioning or controlled externally at the water source.  
         [0046]    In operation then, until paint is to be applied to a paintable surface, paint concentrate is maintained apart from water in the reservoir. Just prior to painting, a conduit, normally a garden hose is attached to the paint head under waterline pressure and turned on with the valve closed. The valve is opened to its first position and concentrate begins to flow, either by siphon or by gravity feed, into the mixing chamber where it mixes with water flowing through the mixing chamber in the preferred ratio of 1:15-17 simultaneously as the mixed composition is discharged through the nozzle, directed toward a paintable surface. When the water evaporates, a dry film of paint remains on or absorbed into the surface, or both. Upon completing a painting period, the valve is turned to its third position to flush the paint composition from the mixing chamber and nozzle, blocking concentrate flow from the reservoir while allowing water to flow through the mixing chamber and nozzle.  
         [0047]    It is to be understood that these embodiments merely exemplify the invention. One skilled in the art will recognize that various modifications and adaptations can be made in the device as described and the method of employing this or another device to exploit the invention. Such modifications and adaptations within the ability of one skilled in the art are deemed to be within the scope of the present application.
An apparatus adapted to mix in a mixing chamber within the apparatus a waterless paint concentrate maintained in a reservoir within the apparatus. The concentrate is stored in the reservoir in a concentration unsuitable for application to a paintable surface. The concentrate is mixed with water received into the mixing chamber under external waterline pressure forming a paint suitable for application to a paintable surface. The paint is then discharged from the apparatus through a spray nozzle. Mixing occurs in the apparatus concurrently with discharge through the nozzle as water flows through the apparatus. The apparatus as largely a container of waterless paint concentrate with a simple mix and discharge spray head attached is disposable after consumption of the concentrate without need for cleaning.