Abstract:
A paint spray gun for use in association with a HVLP turbine blower and an attachable paint container divides input air flow into two horizontally adjacent channels. Air flow through one channel remains open whereas air flow through the second channel may be varied by a side air controller such that when air flow is cut off from the second channel, the paint mixture is sprayed in a substantially circular shape whereas when air flows through the second channel the paint mixture is sprayed in a substantially fan shape. 
     In another embodiment, a rotatable nipple is positioned to redirect some air flow from the channels to drive paint from the paint container.

Description:
FIELD OF THE DISCLOSURE 
       [0001]    The disclosure relates generally to spray guns operated with air supplied by a high-volume, low pressure (HVLP) turbine blower to spray liquids such as paint. 
       BACKGROUND 
       [0002]    Various spray guns are known in the art. Some rely on high pressure air flows, typically in the range of 40-50 pounds per square inch, to atomize and discharge liquids. Others rely on high-volume, low pressure (HVLP) air flows, typically under 10 pounds per square inch. 
         [0003]    Various HVLP spray guns rely on standard compressors. Others rely on high-volume, low pressure turbine blowers that are often used in association with paint sprayers. Turbine air flow is constant and can be varied by a turbine motor from approximately 2 to 10 PSI. Turbine motors are preferred as they result in a more efficient atomization of liquids and lower wastage of liquid. 
         [0004]    Various HVLP turbine spray guns are known in the art. Some rely on fan size adjustment at the rear. Some rely on fan size adjustment at the front air jet. Others rely on fan size adjustment, side-mounted behind the front barrel. 
       SUMMARY 
       [0005]    An embodiment of the present disclosure describes an apparatus for spraying liquids for use in association with an HVLP blower and a fluid container. The apparatus has an air inlet port which can be connected to the HVLP blower. Air is divided into two horizontally adjacent channels, a variable channel and an open channel, both in flow communication with the air inlet port and both receiving air from the HVLP blower. A side controller is positioned such that the flow of air through the variable channel can be varied whereas the air flow through the open channel remains constant. The spray head is for mixing air from one or both channels as well as fluid from the fluid container. 
         [0006]    More specifically, the open channel feeds air into the centre orifice and the variable channel feeds air into two side orifices such that when air is cut off from the variable channel the output fluid mixture has a substantially circular shape and when air flows through the variable channel the output fluid mixture has a substantially fan shape. 
         [0007]    In another embodiment, a rotatable nipple extends from one or more of the spray gun&#39;s air channels and a second nipple extends from the fluid container such that the nipples are connected by a tube and some air is diverted from the channels to drive fluid from the container to the spray head. 
         [0008]    In an alternate embodiment, the fluid container can be located above the spray gun such that gravity in addition to pressure drives the fluid into the spray head. 
         [0009]    In another embodiment, a common trigger controls all air flow from the air inlet port such that fluid mixture only exits the spray gun when the trigger is activated. 
         [0010]    The air and liquid may be mixed externally of the spray head. 
         [0011]    Further features will be described or will become apparent in the course of the following detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a perspective view of the left profile of an embodiment of the spray gun; 
           [0013]      FIG. 2  is an exploded perspective view of the left profile of an embodiment of the spray gun and showing the components of the side air controller and the rotatable nipple; 
           [0014]      FIG. 3  is a side view of the left profile of an embodiment of the spray gun with an attached fluid container; 
           [0015]      FIG. 4   a  is a side view of an embodiment of the spray gun; 
           [0016]      FIG. 4   b  is a cross sectional view of a portion of an embodiment of the spray gun showing the variable channel when air is allowed to flow through; 
           [0017]      FIG. 5   a  is a side view of an embodiment of the spray gun and showing rotation of the side air controller; 
           [0018]      FIG. 5   b  is a cross sectional view of a portion of an embodiment of the spray gun showing the variable channel when air is cut off by the side air controller; 
           [0019]      FIG. 6  is a cross sectional view of a portion of an embodiment of the spray gun showing the rotatable nipple; 
           [0020]      FIG. 7  is a cross sectional view of the horizontally adjacent channels showing the side air controller positioned on the left channel; and 
           [0021]      FIG. 8  is a blown apart perspective view of an alternate embodiment of the spray gun showing a top mounted gravity container. 
       
    
    
       [0022]    The embodiments will now be described by way of example only, with reference to the accompanying drawings, in which: 
       DETAILED DESCRIPTION 
       [0023]    A high volume low pressure manual spray gun that operates from a standard HVLP turbine blower is shown in  FIGS. 1 through 8 . The spray gun shown in  FIGS. 1 through 7  is configured for a bottom mounted liquid container and the spray gun shown in  FIG. 8  is configured for a top mounted liquid container  230 . The gun has a barrel  165  that supports a spray head  185 . A handle tube  135  (shown in  FIG. 8 ) extends downwardly from the barrel  165  and is surrounded by an insulating handle  140 . An inlet port  145  is at the bottom of the handle tube  135  and is for receiving compressed air from an HVLP blower such as a turbine blower (not shown). Referring to  FIG. 8 , a conventional air valve  80  mounted above the handle  140  controls the flow of compressed air through the gun. Valve  80  includes a valve spring  85  and a fluid screw nut  90 . A conventional liquid needle valve  95  extends centrally along the interior of the barrel  165  and engages a liquid jet  15  in the spray head  185  to control discharge of liquid. The needle valve  95  includes a liquid valve spring  100  and a fluid adjustment knob  105 . The barrel  165  includes a liquid valve seal  45  and a liquid valve seal nut  50 . 
         [0024]    The spray head  185  has a liquid jet  15  that discharges liquid received from the container and an air jet  10  surrounds the liquid jet  15 . The air valve  80  and liquid needle valve  95  are operated with a common trigger  155  in sequence to ensure that paint is not introduced before atomizing air. The air flows within the barrel  165  are directed through passages in the air jet  10  to atomize and spray the discharged liquid. 
         [0025]    Trigger  155  is pivotally attached to the barrel with a trigger pin  160  and a retaining ring  150 . Trigger  155  is operably connected to air valve  80  and liquid needle valve  95 . 
         [0026]    Referring to  FIGS. 4 ,  5 , and  7 , spray gun has a left or variable air channel  180  and a right or open air channel  175 , both of which are in flow communication with the air inlet  145 . In use, air flows in through the air inlet  145 , through the handle tube  135  and into a main air channel  170 . It is then diverted into variable air channel  180  and open air channel  175 . It then flows into the spray head  185 . A side-mounted fan pattern control knob  125  controls a side air controller  110  to limit air through the left air channel or variable air channel  180  in the barrel  165 . The side air controller  110  is rotatably mounted in the barrel  165 . A control knob nut  120  is connected to an air deflector seal  115  and secures the controller  110  to the barrel  165 . The side-mounted fan pattern control knob  125  is connected to the controller  110  with a locking screw  130 . 
         [0027]    Referring to  FIG. 8 , an air divider  35  disperses air through an air diffuser  20  to the air jet  10  to increase or decrease the size of the fan pattern of the atomized liquid discharge. When air flows through both air channels  175 ,  180  in the front of barrel  165  the air flows through the side holes and center hole of the air jet  10  producing a large size fan pattern shape. When air is cut off to the left air channel or variable air channel  180 , air flows only through the right air channel  175  to the center orifice of the air jet  10  producing a circular pattern. 
         [0028]    As shown in  FIG. 8 , the spray head  185  includes a collar  5 , an air jet  10 , a liquid jet  15 , and air diffuser  20 , a diffuser seal  25 , an air divider seal  30  and an air divider  35 . 
         [0029]    As shown in  FIG. 3 , part of the air flow in the spray gun is diverted into a liquid container  200  attached below the spray gun to force liquid into the spray head  185 . Note if the top mounted liquid container  230  is attached so that it is above the barrel  165 , as shown in  FIG. 8 , gravity plus pressurized air from the flexible tube  190  will feed the liquid into the spray gun. A rotatable nipple assembly  70  at the rear of the barrel  165  supplies pressurizing air to the container  200  through a flexible tube  190  attached to another nipple  75  on container  200 . The rotatable nipple assembly  70  allows the operator to set the direction of nipple to his preference to accommodate the container  200  or top mounted container  230 . At the spray head  185 , air from the variable air channel  180  and from the open air channel  175  is mixed with fluid from the fluid container  200  to produce a fluid mixture which is then ejected from the spray head. In the embodiment shown herein the air and the fluid is mixed externally of the spray head  185 . 
         [0030]    The rotatable nipple assembly  70  includes a nipple  75 , a rotatable portion  205 , a small seal  210 , a nipple assembly nut  215 , a large seal  220  and a retaining ring  225 . The rotatable nipple assembly  70  allows the flexible tube  190  (shown in part in  FIG. 3 ) to be connected to the container  200 . The flexible tube  190  can rotate so that air can freely flow through flexible tube  190 . The container  200  is connected to the barrel  165  through the fluid coupler  40 . 
         [0031]    To control the size of the fan pattern by turning a knob requires the pressurized air to pass from a main air channel  170  through to the right air channel or open air channel  175  and left air channel or variable  180  that are separate and distinct. The left air channel  180  airflow is controlled by a side air controller  110 . The right air channel  175  is always fully open for constant airflow. These passages reside in the main barrel  165  behind the spray head  185 . Airflow through the right air channel  175  is diverted by the air divider  35  through to the air diffuser  20  so that air flows only through the center hole of the air jet  10 . Airflow through the left channel is controlled by a rotating side air controller  110  allowing varying levels of airflow through to the spray head  185 . The air flow from the left air channel  180  is diverted by the air divider  35  and through the air diffuser  20  so that air flow can only pass through the side holes of the air jet  10 . 
         [0032]    When air is passed through both air channels the atomized liquid is discharged in a wide ‘fan’ pattern. When air is completely cut off by the side air controller  110  in the left air channel  180 , the atomized liquid is discharged in a small round circular pattern. By turning the fan control knob  125  to restrict and vary air volume through the spray head  185 , a full incremental range of fan sized patterns can be produced. 
         [0033]    Unlike other HVLP turbine spray guns with side mounted fan control, the barrel  165  is split down the middle forming two natural horizontal air channels set side by side. This method allows for both right  175  and left air channels  180  to have a much greater cross sectional area, as compared to spray guns where the channels are an upper and lower channel, resulting in greater airflow through the spray head  185 . The left air channel  180  is fitted with a rotating side air controller  110  to reduce or shut off the air flow thereby adjusting the size of the fan of the atomized liquid discharge. 
         [0034]    A unique rotatable nipple assembly  70  placed in a unique location at the rear of the barrel  165  supplies pressurizing air to the container through a flexible tube  190  attached to the nipple  75 . The flexible tube  190  connects nipple  75 , which is part of the rotatable nipple assembly  70 , to the other nipple  75  attached to the liquid container  200 . A liquid tube  195  extends into the liquid container  200 . Pressurized air from flexible tube  190  is connected to the liquid container  200  so that liquid container  200  is pressurized and liquid is forced into the spray gun when the trigger  155  is activated. 
         [0035]    Several advantages are achieved over the prior art, particularly HVLP turbine spray guns with side mounted fan pattern control. Placing the two air channels side by side allows for a greater volume of airflow through the spray head  185  reducing back pressure and air turbulence in the gun barrel  165  and through the spray head  185 . Placing the two air passages side by side streamlines the linear air flow producing superior atomization. Use of a simpler, shorter side air controller  110  reduces the incidence of jamming and the need for periodic adjustment. 
         [0036]    An alternate embodiment is shown in  FIG. 8  wherein the barrel  165  is provided with a top liquid inlet. Inlet  65  has a fluid coupler  55  and a fluid coupler seal  60 . In this embodiment a top mounted liquid container  230  may be attached to the top liquid port  65  and the liquid may be gravity fed into the spray gun. 
         [0037]    As used herein, the terms, “comprises” and “comprising” are to be construed as being inclusive and open ended, and not exclusive. Specifically, when used in the specification and claims, the terms, “comprises” and “comprising” and variations thereof mean the specified features, steps or components are included. These terms are not to be interpreted to exclude the presence of other features, steps or components. 
         [0038]    As used herein, the term “exemplary” means “serving as an example, instance, or illustration,” and should not be construed as preferred or advantageous over other configurations disclosed herein. 
         [0039]    As used herein, the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is “substantially” enclosed would mean that the object is either completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained. The use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result. 
         [0040]    Unless defined otherwise, all technical and scientific terms used herein are intended to have the same meaning as commonly understood to one of ordinary skill in the art.