Abstract:
A paint spray system including paint sprayer, a pressurized air generator, a pressurized air duct and an air control mechanism. The paint sprayer has a spray nozzle, the pressurized air generator has a blower, the pressurized air duct connects the blower to the spray nozzle, and the air control mechanism includes a throttle mechanism and is situated in the course of the pressurized air duct. The air control mechanism includes an outlet mechanism, wherein a decreasing of an aperture cross section of the throttle mechanism automatically leads to an increasing of an aperture cross section of the outlet mechanism and vice versa. The aperture cross sections existing in individual settings of the throttle mechanism and the outlet mechanism are attuned to each other such that a dynamic pressure generated at the blower remains constant in the individual aperture settings of the throttle mechanism and the outlet mechanism.

Description:
[0001]    This application claims the benefit under 35 USC §119(a)-(d) of German Application No. 10 2014 112 640.8 filed Sep. 2, 2014, the entirety of which is incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a paint spray system, especially an HVLP paint spray system, and an air control mechanism for a paint spray system. 
       BACKGROUND OF THE INVENTION 
       [0003]    A paint spray system is known from DE 20 2006 011 671 U1, which comprises a paint sprayer, a pressurized air generator, a pressurized air duct and an air control mechanism, wherein the paint sprayer has a spray nozzle, wherein the pressurized air generator has a blower, wherein the pressurized air duct connects the blower to the spray nozzle, wherein the air control mechanism comprises a throttle mechanism, and wherein the air control mechanism is situated in the course of the pressurized air duct. 
       SUMMARY OF THE INVENTION 
       [0004]    The problem which the present invention proposes to solve is the development of a paint spray system and an air control mechanism in which the air flow through the blower or the working point of the blower is held constant despite a change in the volume of an air flow supplied to the nozzle, so that the paint spray system can be designed without costly electric power adjustment, yet still provide an altered air flow to the nozzle. 
         [0005]    In the paint spray system of the present invention, the air control mechanism comprises an outlet mechanism, through which pressurized air can flow out into the surroundings, wherein a decreasing of an aperture cross section of the throttle mechanism automatically leads to an increasing of an aperture cross section of the outlet mechanism and wherein an increasing of the aperture cross section of the throttle mechanism automatically leads to a decreasing of the aperture cross section of the outlet mechanism and wherein the aperture cross sections existing in individual settings of the throttle mechanism and the outlet mechanism are attuned to each other such that a dynamic pressure generated at the blower remains constant in the individual aperture settings of the throttle mechanism and the outlet mechanism. This ensures that the blower works under constant conditions and thus optimally, regardless of a volume of air flow supplied to the nozzle, and neither heats up unacceptably as a result of a high dynamic pressure nor delivers a higher volume flow as a result of a low dynamic pressure, which creates a needless amount of moving air in the vicinity of the painting work and increases the electricity consumption. Thus, the crux of the invention is to maintain constant dynamic pressure at the blower by attuning the aperture cross sections of the throttle mechanism and the outlet mechanism in each setting of the throttle mechanism and in each setting of the outlet mechanism. 
         [0006]    Furthermore, the air control mechanism comprises coupling means, wherein the coupling means connect the throttle mechanism and the outlet mechanism such that an actuator determining the aperture cross section of the throttle mechanism and an actuator determining the aperture cross section of the outlet mechanism are mechanically or electromechanically or electronically or pneumatically or hydraulically coupled to each other. The coupling means enable both a synchronous adjustment of the throttle mechanism and the outlet mechanism and an arrangement of the throttle mechanism and the outlet mechanism separate from each other, as well as the realization of a translation between the throttle mechanism and the outlet mechanism so that their aperture cross sections, which they make clear in the individual settings, can be predetermined according to the requirements. 
         [0007]    Furthermore, when the paint spray system has a multiple-piece design in which the pressurized air generator, the pressurized air duct and the paint sprayer are designed as separate individual components, the throttle mechanism and the outlet mechanism of the air control mechanism are arranged in the pressurized air duct preferably in the immediate vicinity of the pressurized air generator or preferably in the immediate vicinity of the paint sprayer or in the paint sprayer or in the pressurized air generator. An arrangement near the pressurized air generator or in the pressurized air generator brings the advantage that the outlet mechanism is far away from the spray nozzle and air emerging through the outlet mechanism does not affect the spray jet. An arrangement near the paint sprayer or in the paint sprayer brings the advantage that the user can conveniently make an adjustment to the setting. 
         [0008]    When the paint spray system has a single piece design in which the pressurized air generator, the pressurized air duct, the paint sprayer and the air control mechanism are designed as a single-piece compact unit, the air control mechanism with its throttle mechanism and its outlet mechanism are arranged in the pressurized air duct or immediately upstream from the spray nozzle or immediately downstream from the blower. Once again, this brings the advantages indicated in the previous paragraph. 
         [0009]    It is also provided that the air control mechanism is outfitted with activating means, wherein a changing of the aperture cross section of the pressurized air duct and a changing of the aperture cross section of the outlet mechanism is done by the activating means, wherein the activating means in particular is adjustable continuously or in steps and in particular in a locking or nonlocking manner and/or wherein an adjusting of the activating means changes the aperture cross sections in a linear manner or changes the aperture cross sections in a nonlinear manner and/or wherein the activating means are configured as the housing of a muffler and/or as part of the air guidance mechanism and especially as a guide vane or air scoop. In this way, the desired adjustment of the pressurized air for the spray nozzle can be done with one hand on the activating means, without having to interrupt the spraying or painting process for this or without having to set down the paint sprayer for this. 
         [0010]    Furthermore, the directional control valve comprises a guide element and a bearing element, wherein the guide element is configured in particular as a linear slider or rotary slider and is moved with the activating element and wherein the bearing element is arranged in the pressurized air duct in the pressurized air flow direction upstream from the guide element. This enables a mechanically simple construction, which additionally offers the advantage that the guide element is pressed by the pressurized air against the bearing element, thereby accomplishing a sealing between these two structural parts. 
         [0011]    It is also provided that the outlet mechanism is outfitted with a muffler, wherein the muffler comprises in particular an open-pore foam body through which pressurized air emerging from an outlet opening of the outlet mechanism is taken, and/or the outlet mechanism is outfitted with an air guidance mechanism which is placed after an outlet opening of the outlet mechanism, wherein the air guidance mechanism deflects outgoing pressurized air at an angle of at least 90° from a spraying direction of the paint sprayer. In this way, one can both avoid unwanted noise production and also prevent an unwanted influencing of the spray jet by the pressurized air emerging from the outlet duct. 
         [0012]    It is also provided that the paint spray system is outfitted with a paint tank, whose paint is delivered with pressurized air, which branches off from the pressurized air duct, wherein the pressurized air for the operation of the paint tank is diverted from the pressurized air duct looking in the direction of flow from a first supply connection, arranged upstream from the air control mechanism, or from a second supply connection, arranged downstream from the air control mechanism, or from both supply connections. In this way, once the volume of pressurized air taken to the spray mechanism has been adjusted, such that the volume flow taken to the spray mechanism is reduced, it is possible to supply the paint tank with higher or lower pressure as necessary. 
         [0013]    Furthermore, it is provided that the paint tank is connected to the two supply connections across a switching valve via two supply lines, wherein depending on a switch setting of the switching valve pressurized air is fed to the paint tank from only one of the two supply connections or pressurized air is supplied to the paint tank from both supply connections. Thereby, one can easily realize a supply of pressurized air to the paint tank which can be adapted to three pressure levels. 
         [0014]    Finally, the invention provides for the configuration of an air control mechanism as a retrofitted part, wherein the air control mechanism comprises a throttle mechanism and an outlet mechanism, wherein a decreasing of an aperture cross section of the throttle mechanism automatically leads to an increasing of an aperture cross section of the outlet mechanism and wherein an increasing of an aperture cross section of the throttle mechanism automatically leads to a decreasing of the aperture cross section of the outlet mechanism, and wherein the aperture cross sections existing in individual settings of the throttle mechanism and the outlet mechanism are attuned to each other such that, when the air control mechanism is installed between the blower and the spray nozzle, a dynamic pressure generated at the blower remains constant in the individual settings. With such a retrofitted part or such an adapter, an existing paint spray system can be easily retrofitted so that the volume of pressurized air supplied to its spray nozzle can be changed without increasing the dynamic pressure at the pressurized air generator or without changing its intended operating point. 
         [0015]    In the sense of the invention, by a paint spray system is meant both paint spray systems which comprise a paint spray gun and paint spray systems which comprise a paint spray lance. Furthermore, both variants include either an integrated pressurized air generator or a pressurized air generator which is connected across a pressurized air hose. 
         [0016]    In the sense of the invention, a blower of a pressurized air generator is designed in particular as a radial blower. A radial blower here is a blower which takes in air parallel or axially to an axis of rotation of a fanwheel and blows it out by rotation of the fanwheel deflected through 90° and radially to its axis of rotation. 
         [0017]    In the sense of the invention, by constant dynamic pressure is meant a dynamic pressure at the blower in particular, which deviates at most 10% upward or at most 20% downward during adjustments to the air control mechanism, but preferably at most by only 5% upward or at most only 10% downward from a nominal pressure. 
         [0018]    In the air control mechanism of the invention, in the direction of flow from the blower to the gun, the outlet mechanism for delivering pressurized air to the surroundings is arranged upstream from the throttle mechanism, i.e. before the throttle mechanism, or at least at the position of the throttle mechanism which is placed in the flow duct to the spray nozzle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a schematic representation of a paint spray system according to the invention; 
           [0020]      FIG. 2  is a first variant embodiment of an air control mechanism of the paint spray system shown in  FIG. 1  in exploded view; 
           [0021]      FIG. 3  is a perspective representation of a rotary insert belonging to the air control mechanism shown in  FIG. 2 ; 
           [0022]      FIG. 4  is the air control mechanism shown in  FIGS. 2 and 3  in fully installed condition in a perspective representation; 
           [0023]      FIG. 5  is the air control mechanism shown in  FIGS. 2 and 3  in fully installed condition in top view, the throttle mechanism being set to minimum flow rate; 
           [0024]      FIG. 6  is a sectional view through the representation of  FIG. 5 , corresponding to sectioning line V-V; 
           [0025]      FIG. 7  is a sectional view through the representation of  FIG. 6 , corresponding to sectioning line VI-VI; 
           [0026]      FIG. 8  is a representation of  FIG. 6  looking in direction VIII; 
           [0027]      FIG. 9  is a perspective view of the sectional representation shown in  FIG. 6 ; 
           [0028]      FIG. 10  is the air control mechanism shown in  FIGS. 2 and 3  in fully installed condition in top view, the throttle mechanism being set to minimum flow rate; 
           [0029]      FIG. 11  is a sectional view through the representation of  FIG. 10 , corresponding to sectioning line XI-XI; 
           [0030]      FIG. 12  is a sectional view through the representation of  FIG. 11 , corresponding to sectioning line XII-XII; 
           [0031]      FIG. 13  is a representation of  FIG. 10  looking in direction VIII; 
           [0032]      FIG. 14  is a perspective view of the sectional representation shown in  FIG. 11 ; 
           [0033]      FIG. 15  is a second variant embodiment of an air control mechanism of the paint spray system shown in  FIG. 1  in sectional side view; 
           [0034]      FIG. 16  is a third variant embodiment of an air control mechanism of the paint spray system shown in  FIG. 1  in sectional side view; 
           [0035]      FIG. 17  is a fourth variant embodiment of an air control mechanism of the paint spray system shown in  FIG. 1  in sectional side view; 
           [0036]      FIG. 18  is a fifth variant embodiment of an air control mechanism of the paint spray system shown in  FIG. 1  in sectional side view; 
           [0037]      FIG. 19  is a schematic representation of a second paint spray system which is designed as a single-piece paint spray system and 
           [0038]      FIG. 20  is a schematic representation of a sixth air control mechanism. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0039]      FIG. 1  shows schematically a paint spray system  1  according to the invention. The paint spray system  1  is designed as a High-Volume-Low-Pressure paint spray system  1 ′ or HVLP paint spray system. The paint spray system  1  comprises a paint sprayer  2 , a pressurized air generator  3 , a pressurized air duct  4  and an air control mechanism  5 . The paint sprayer  2  is designed as a spray gun  6  and comprises a housing  7 , a front end  8  with a spray nozzle  9 , a paint tank  10 , a handle  11  with a trigger  12  and a connection  13  for the pressurized air duct  4 . The pressurized air generator  3  comprises a housing  14 , an electric blower  15 , a connection  16  for the pressurized air duct  4  and an air inlet  17  for taking in ambient air. The pressurized air duct  4  connects the blower  15  to the spray nozzle  9  across the connections  16  and  13 . The air control mechanism  5  shown schematically in  FIG. 1  in turn comprises a throttle mechanism  18  and an outlet mechanism  19  and is arranged in the pressurized air duct  4 . The air control mechanism  5  is supplied with pressurized air D 1  at the blower side from the blower  15  across a first segment  4   a  of the pressurized air duct  4 . The pressurized air D 1  in the air control mechanism  5  at the blower side is either conducted further into a second segment  4   b  of the pressurized air duct  4  to the spray nozzle  9  with the outlet mechanism  19  closed and the throttle mechanism  18  fully open, or the pressurized air D 1  at the blower side is further conducted, as shown symbolically by arrows in  FIG. 1 , as a first portion of pressurized air D 2  at the spray side with the throttle mechanism  18  partly closed to the spray nozzle  9  and blown out to the surroundings U as a second portion with outlet mechanism  19  partly open as exhaust air D 3 . In this case, an aperture cross section A 18  (see  FIG. 7 ) of the throttle mechanism  18  and an aperture cross section A 19  (see  FIG. 7 ) of the outlet mechanism  19  in each position of the adjustment dictated by the throttle mechanism  18  and in each position dictated by the outlet mechanism  19  are attuned to each other by experiments or calculations so that a dynamic pressure PS prevailing at the blower  15 , e.g. at the connection  16 , remains constant regardless of any setting dictated by the throttle mechanism  18  for the outlet mechanism  19  or by the outlet mechanism  19  for the throttle mechanism  18 . The air control mechanism  5  also comprises coupling means  20 . The coupling means  20  connect the throttle mechanism  18  and the outlet mechanism  19  such that an actuator determining the aperture cross section A 18  of the throttle mechanism  18  and an actuator determining the aperture cross section A 19  of the outlet mechanism  19  are mechanically connected to each other. 
         [0040]    According to variant embodiments not shown, an electromechanical or an electronic coupling of the actuators of the throttle mechanism and the outlet mechanism is also provided. An electromechanical coupling comprises a driving means, especially an electric motor, and a force transmittal means powered by the driving means, especially a toothed rack or a belt, wherein the force transmittal means acts on the two actuators and moves them. An electronic coupling comprises two driving means, especially two electric motors or two electromagnets, electronics, and a manually operated controller, wherein the electronics actuate the driving means depending on a selected setting or adjustment of the controller, which is configured in particular as a slide control or rotary controller or by two keys, while each driving means is connected to one actuator and the driving means bring the actuators into positions dictated by the electronics. 
         [0041]      FIG. 1  shows the paint spray system  1  in a multiple-piece design, in which the pressurized air generator  3 , the pressurized air duct  4  and the paint sprayer  6  are designed as separate individual components for transport, cleaning or storage purposes. The air control mechanism  5  with its throttle mechanism  18  and its outlet mechanism  19  are arranged here in the pressurized air duct  4 . This ensures that exhaust air D 3  blown out from the outlet mechanism  19  into the surroundings U does not have any disturbing influence on the spraying work. 
         [0042]      FIGS. 2 and 3  show a first variant embodiment of the air control mechanism of the paint spray system shown in  FIG. 1  in exploded view. The air control mechanism  101  shown as individual parts in  FIGS. 2 and 3  is configured as an adapter, which can be installed in the pressurized air duct  4  (see  FIG. 1 ). The air control mechanism  101  comprises an adapter pipe  102 , an activating means  104  designed as a clasp  103 , a rotary insert  105 , which is formed by a first actuator  106   a  and a second actuator  106   b  (see  FIG. 3 ), and a muffler  107 . The adapter pipe  102  comprises a first connection  102   a  for attaching the first segment  4   a  of the pressurized air duct  4  and a second connection  102   b  for attaching the second segment  4   b  of the pressurized air duct  4  (see  FIGS. 1 and 2 ). 
         [0043]      FIGS. 4 to 9  show different views of the air control mechanism  101 , wherein the air control mechanism  101  is in an assembled condition here and stands in a position in which its throttle mechanism  18  is set for a minimum flow rate. 
         [0044]      FIGS. 10 to 14  show different views of the air control mechanism  101 , wherein the air control mechanism  101  is likewise in an assembled condition here, but stands in a position in which its throttle mechanism  18  is set for a maximum flow rate. 
         [0045]    As is evident for example from  FIGS. 6 to 9 , the rotary insert  105 , which together with a perforated wall  102   d  formed in a channel  102   c  of the adapter pipe  102  forms the throttle mechanism  18  (see  FIG. 6 ), can turn about an axis of rotation d 102  in the assembled state of the air control mechanism  101  in the adapter pipe  102 . The rotary insert  105  is supported by a journal  102   e  formed on the wall  102   d.  The journal  102   e  projects into a seat  105   a  of the rotary insert  105 . In order to ensure a reliable bearing of the rotary insert  105  against the wall  102   d  in operation, the journal  102   e  is directed from the wall  102   d  against a direction of flow S 1  of the pressurized air D 1 , so that the rotary insert  105  in operation is pressed by the pressurized air D 1  flowing through the adapter pipe  102  against the wall  102   d.    
         [0046]    It is evident from  FIG. 3  that the rotary insert  105  has four axially oriented triangular openings  108   a  to  108   d  in its first guide element  106   a  and an axially oriented slotlike opening  109  in its second guide element  106   b.  Furthermore, a pocket  110  is formed beside the slotlike opening  109 . This pocket  110  is matched up with a lug  111 , which is formed on the clasp  103  beneath a handle grip R 103 . In the assembled condition of the air control mechanism  101 , the clasp  103  reaches by its lug  111  through a window  112  formed in the adapter pipe  102  (see  FIGS. 2 ,  3  and  6 ) into the pocket  110  of the rotary insert  105 , so that the clasp  103  and the rotary insert  105  are coupled together and the rotary insert  105  can turn about the axis  102   e  on the outside by means of the clasp  103 . The turning ability here is limited to an angle of rotation allowed by the window  112  for the lug  111 . The window  112  formed in the adapter pipe  102  has a dual function and not only forms a passageway for the lug  111  of the clasp  103 , but also forms an outlet opening  112   a  for pressurized air D 3  of the outlet mechanism  19 , which is formed by the actuator  106   b  configured on the rotary insert  105  and the adapter pipe  102  with the window  112 . In this way, it is possible for the pressurized air D 1  to flow out into the surroundings U as pressurized air D 3 , in which the rotary insert  105  is oriented by its slotlike opening  109  toward the window  112  in the adapter pipe  102 . Inasmuch as the opening  109  and the window  112  are oriented toward each other (see, for example,  FIG. 7 ), a portion of the pressurized air D 1  emerges as pressurized air D 3  through the opening  109  and the window  112  into a space  113  situated between the clasp  103  and the adapter pipe  102 . Thus, the opening  109  forms an outlet opening  109   a  of the outlet mechanism  19 . The space  113  is filled by the muffler  107 , which is configured as foam plastic. Accordingly, noise produced by the escaping pressurized air D 3  is dampened and the emerging pressurized air D 3  leaves the space  113  through outlet boreholes  115  fashioned in a wall  114  of the clasp  103 . The opening  109  and the pocket  110  are formed in a first wing  116  of the rotary insert  105 . The rotary insert  105  comprises a second wing  117 , which lies opposite the first wing  116 , so that the rotary insert  105  is braced by the outer surfaces  116   a  and  117   a  of its opposite wings  116 ,  117  against an inner wall  118  of the adapter pipe  102  and a skewing of the rotary insert  105  due to an activation by the clasp  103  is prevented. In  FIG. 2 , an opening  119  is indicated at the muffler  107 , through which the clasp  103  enters by its lug  111  when it is coupled with the rotary insert  105 . 
         [0047]    Thanks to the activating means  104  of the air control mechanism  101  fashioned as a clasp  103 , when the activating means  104  is turned about the axis of rotation d 102  there occurs a changing of the aperture cross section A 18  of the throttle mechanism  18  and at the same time a changing of the aperture cross section A 19  of the outlet mechanism  19 . The activating means  104  can move continuously and without locking between a minimum setting MIN indicated in  FIGS. 5 to 9  and a maximum setting MAX indicated in  FIGS. 10 to 14 . In the minimum setting MIN (see especially  FIG. 7 ) the aperture cross section A 18  of the throttle mechanism is reduced to a minimum and the aperture cross section A 19  of the outlet mechanism  19  is opened to a maximum. In the maximum setting MAX (see especially  FIG. 12 ) the aperture cross section A 18  of the throttle mechanism is opened to a maximum and the aperture cross section A 19  of the outlet mechanism  19  is totally closed. By adjusting the activating means  104 , the aperture cross section A 18  of the throttle mechanism  18  is changed by a first function depending on the angle of rotation and the aperture cross section A 19  of the outlet mechanism  19  is changed by a second function depending on the angle of rotation. The activating means  104  is designed not only as a housing of the muffler  107 , but also as part of the air guide mechanism  101  it forms an air scoop  120 , which deflects the pressurized air D 3  to opposite sides. Coupling means  121  of the air guide mechanism  101  are formed in the present design by the clasp  103  and the activating means  104 , since the clasp  103  is used to activate both the first actuator  106   a  and the throttle mechanism  18  comprising the wall  102   d  and also the second actuator  106   b  and the outlet mechanism  19  comprising the adapter pipe  102  with the window  112 . In this case, the two actuators  106   a  and  106   b  form a single-piece guide element  122  for the pressurized air and the wall  102   d  and the inner wall  118  of the adapter pipe  102  form a bearing element  123  for the guide element  122 . The guide element  122  in the form of the rotary insert  105  is fashioned as a rotary slider  124 . 
         [0048]      FIG. 1  furthermore shows schematically a pressurized air supply  50  for the paint tank  10 , by which paint is delivered from the paint tank  10  to the spray nozzle  9 . The pressurized air supply  50  comprises two feed lines  51 ,  52 , a switch valve  53  and a supply line  54 . Through the feed lines  51 ,  52  the switch valve  53  is connected to a supply connection  55  arranged at the pressurized air duct  4  upstream from the air control mechanism  5  in the flow direction of pressurized air and to a supply connection  56  arranged downstream from the air control mechanism  5  at the pressurized air duct  4 , so that pressurized air flows via both feed lines  51 ,  52  to the switch valve  53 . The switch valve  53  depending on its switch setting conveys pressurized air via the supply line  54  to the paint tank  10 . The paint tank  10  is either supplied exclusively with pressurized air from the first supply connection  55  in a first switch setting of the switch valve or exclusively with pressurized air from the second supply connection  56  in a second switch setting of the switch valve or in a third switch setting it is supplied with pressurized air from both supply connections  55 ,  56  or in a fourth switch setting it is blocked off from pressurized air supply. Once the throttle mechanism  18  is not in a maximum setting and the pressurized air can flow unhindered through the air control mechanism  5 , the pressurized air will be present at the two supply connections  55 ,  56  with different pressure, so that the more suitable pressure for the delivery of the paint can be chosen. Thanks to the third switch setting of the switch valve a further pressure potential is available lying between the first and the second pressure potential. 
         [0049]    According to another variant embodiment it is also provided that the pressurized air supply comprises only one supply line, by which the paint tank is manually connected optionally to the first or the second supply connection, while the supply connection to which the supply line is not connected is naturally closed, for which it is designed in particular as a self-closing valve. 
         [0050]      FIG. 15  shows a second variant embodiment of an air control mechanism  201  of the paint spray system of  FIG. 1  in sectional side view. The air control mechanism  201  comprises an adapter pipe  202  with a first and a second connection  202   a,    202   b  for the pressurized air duct  4  shown in  FIG. 1 . Moreover, the air control mechanism  201  comprises a slide insert  205  with an opening  208   a,  which can be shifted in linear manner in front of a perforated wall  202   d  of the adapter pipe  202  and routes the pressurized air depending on its position with respect to a recess  202   f  of the adapter pipe  202  to different parts in the adapter pipe  202  and out from the adapter pipe  202  into the surroundings U. The slide insert  205  forms a linear slide  225 . 
         [0051]    In  FIG. 16  is shown a third variant embodiment of an air control mechanism  301  of the paint spray system of  FIG. 1  in sectional side view. The air control mechanism  301  comprises an adapter pipe  302  with a first and a second connection  302   a,    302   b  for the pressurized air duct  4  shown in  FIG. 1 . Moreover, the air control mechanism  301  comprises a slide insert  305  with three openings  308   a,    308   b  and  308   c,  which can be moved in a linear manner and lies behind a triple-perforated wall  302   d  of the adapter pipe  302  and routes the pressurized air depending on its position to different parts in the adapter pipe  302  and out from the adapter pipe  302  into the surroundings U, where the openings  308   a  and  308   b  emerge into the adapter pipe  302  and the opening  308   c  emerges into the surroundings U. The slide insert  305  forms a linear slide  325 . 
         [0052]      FIG. 17  shows a fourth variant embodiment of an air control mechanism  401  of the paint spray systems of  FIG. 1  in sectional side view. The air control mechanism  401  comprises an adapter pipe  402  with a first and a second connection  402   a,    402   b  for the pressurized air duct  4  shown in  FIG. 1 . Furthermore, the air control mechanism  401  comprises a screw insert  405 , by which a single perforated wall  402   d  of the adapter pipe  402  can be closed, wherein the pressurized air under increasing closure of the wall  402   d  can flow out into the surroundings U through an increasing opening of the screw insert. 
         [0053]      FIG. 18  shows schematically a fifth variant embodiment of an air control mechanism  501  of the paint spray systems of  FIG. 1  in sectional side view. The air control mechanism  501  comprises an adapter pipe  502  with a first and a second connection  502   a,    502   b  for the pressurized air duct  4  shown in  FIG. 1 . Furthermore, the air control mechanism  501  comprises a rotary insert  505 , which is fashioned as a rotary plug and admits an increasing outflow of pressurized air into the surroundings U when turned from a middle position. 
         [0054]      FIG. 19  shows schematically a second paint spray system  601 . This is designed as a single-piece paint spray system  601 . In the single-piece paint spray system  601  a pressurized air generator  603 , a pressurized air duct  604 , a paint sprayer  602  and an air control mechanism  605  form a single-piece compact appliance. The pressurized air generator  603  comprises an electric blower  615  and the paint sprayer  602  comprises a spray nozzle  609 . The air control mechanism  605  here with a throttle mechanism  618  and an outlet mechanism  619  is arranged in the pressurized air duct  604 . In regard to the function of the air control mechanism  605 , refer to the description of the air control mechanism shown in  FIG. 1 . Optionally, the second paint spray system  601 , which is designed as an HVLP paint spray system  601 ′, also comprises a pressurized air supply  650  for a paint tank  610  of the paint sprayer  602 . Regarding the function of the pressurized air supply  650 , refer to the description of the pressurized air supply shown in  FIG. 1 . 
         [0055]      FIG. 20  shows schematically a sixth variant embodiment of an air control mechanism  701 . The air control mechanism  701  comprises an adapter pipe  702  with a first and a second connection  702   a,    702   b.  In a channel  702   c  there is fashioned a window  712 , which forms an outlet opening  712   a.  In the channel  702   c  is arranged a first actuator  706   a  in the form of a first pivoting flap  751 . In the outlet opening  712   a  is arranged a second actuator  706   b  in the form of a second pivoting flap  752 . Both flaps  751 ,  752  are each connected to a gear  753 ,  754 , so that a rotation of the gears about axes of rotation  751   a,    752   a  of the flaps  751 ,  752  also produces a rotation of the flap  751 ,  752 . As coupling means  721 , the air control mechanism  701  comprises a toothed belt  755  and another gear  756  with axis of rotation  756   a.  The three gears  753 ,  754  and  756  are arranged at corner points of an imaginary triangle  757  and the toothed belt  755  is passed around them such that a rotation of the third gear  756  is transmitted via the toothed belt  755  to the gears  753  and  754  and thus brings about a turning of the flaps  751 ,  752 . The flap  751  here is shown by solid lines in a position in which the channel  702   c  is fully open and the flap  752  here is shown by solid lines in a position in which the outlet opening  712   a  is fully closed. In this position, a full volume flow will be taken to a spray nozzle, not shown. By broken lines is shown an intermediate position of the air control mechanism  701 , in which the channel  702   c  is slightly closed and the outlet opening  712   a  is slightly opened. In this position, a reduced volume flow is taken to the spray nozzle, not shown, and a lesser volume flow, corresponding to a difference between the full volume flow and the reduced volume flow, is taken via the outlet opening  712   a  into the surroundings U. Thanks to a use of gears  753 ,  754  with different diameters, the mechanical coupling of the actuators  706   a,    706   b  can be adapted, so that the air control mechanism  701  can also be operated with greatly different diameters of the flaps, so that a dynamic pressure on a blower is maintained constant at all adjustments of the air control mechanism. As activating means  704  a pin  704   a  is used, which is connected eccentrically to the third gear  756 , so that the gear  756  can be turned by hand through any given angle. 
       LIST OF REFERENCE NUMBERS 
       [0000]    
       
           1  paint spray system 
           1 ′ HVLP paint spray system 
           2  paint sprayer 
           3  pressurized air generator 
           4  pressurized air duct 
           4   a,    4   b  first, second segment of  4   
           5  air control mechanism 
           6  spray gun 
           7  housing of  7   
           8  front end of  7   
           9  spray nozzle of  7   
           10  paint tank of  7   
           11  handle of  7   
           12  trigger of  7   
           13  connection of  7   
           14  housing of  3   
           15  blower of  3   
           16  connection of  3   
           17  air inlet of  3   
           18  throttle mechanism of  5   
           19  outlet mechanism of  5   
           20  coupling means of  5   
           50  pressurized air supply 
           51 ,  52  supply lines to  53   
           53  switching valve to  53   
           54  supply line between  53  and  10   
           55 ,  56  supply connections at  4   
           101  air control mechanism (first variant) 
           102  adapter pipe 
           102   a  first connection at  102   
           102   b  second connection at  102   
           102   c  channel of  102   
           102   d  perforated wall in  102   
           102   e  journal on  102   d    
           103  clasp 
           104  activating means 
           105  rotary insert 
           106   a  first actuator 
           106   b  second actuator 
           107  muffler 
           108   a - 108   d  opening at  105  and  106   a    
           109  opening at  105  and  106   b    
           110  pocket at  105   
           111  lug at  103   
           112  window in  102   
           112   a  outlet opening formed by  112   
           113  space between  102  and  103   
           114  wall of  103   
           115  outlet borehole in  114   
           116  first wing of  105   
           116   a  outer surfaces of  116   
           117  second wing of  105   
           117   a  outer surfaces of  117   
           118  inner wall of  102   
           119  opening on  107   
           120  air scoop at  103   
           121  coupling means 
           122  guide element 
           123  bearing element for  122   
           201  air control mechanism 
           202  adapter pipe 
           202   a,    202   b  connection at  202   
           202   d  perforated wall of  202   
           202   f  recess of  202   
           205  slide insert 
           208   a  opening in  205   
           225  linear slider 
           301  air control mechanism 
           302  adapter pipe 
           302   a,    302   b  connection of  302   
           302   d  perforated wall of  302   
           305  slide insert 
           308   a - 308   c  openings in  305   
           325  linear slider 
           401  air control mechanism 
           402  adapter pipe 
           402   a,    402   b  connection of  402   
           402   d  perforated wall of  402   
           405  screw insert 
           501  air control mechanism 
           502  adapter pipe 
           502   a,    502   b  connection of  502   
           505  rotary insert 
           601  single-piece paint spray system 
           601 ′ HVLP paint spray system 
           602  paint sprayer 
           603  pressurized air generator 
           604  pressurized air duct 
           605  air control mechanism 
           609  spray nozzle 
           610  paint tank 
           615  blower 
           618  throttle mechanism 
           619  outlet mechanism 
           650  pressurized air supply 
           701  air control mechanism 
           702  adapter pipe 
           702   a,    702   b  first, second connection of  702   
           702   c  channel 
           704  activating means 
           704   a  pin 
           706   a  first actuator 
           706   b  second actuator 
           712  window in  702   
           712   a  outlet opening in  702   
           721  coupling means 
           751  first pivoting flap 
           751   a  pivot axis of  751   
           752  first pivoting flap 
           752   a  pivot axis of  752   
           753 ,  754  gear 
           755  toothed belt 
           756  third gear 
           756   a  pivot axis of  756   
           757  imaginary triangle 
         A 18  aperture cross section of  18   
         A 19  aperture cross section of  19   
         D 1  pressurized air at blower side 
         D 2  pressurized air at sprayer side 
         D 3  exhaust air 
         d 102  pivot axis of  105   
         MIN minimum setting of  101   
         MAX maximum setting of  101   
         PS dynamic pressure at  3   
         R 103  grasping rib on  103   
         S 1  flow direction 
         U surroundings