Abstract:
An extension device for spraying devices has an extension unit, which has, at a first end, a spraying head having at least one material outlet nozzle and, at a second end, means for connecting a spraying device. The extension device is characterized in that the extension unit has a metering and shut-off valve, which has a valve seat element having a valve opening and which has a valve body, that the valve body is arranged between the spraying head and the valve seat element, and that the valve body is fastened to a tension-transmitting element, which extends through the valve opening. The invention further relates to a spraying device for spraying material onto surfaces, with the spraying device having such an extension device.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims the priority benefits of International Patent Application No. PCT/EP2015/054366, filed Mar. 3, 2015, and claims benefit of DE 102014204012.4, which are hereby incorporated herein by reference in their entirities. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to an extension device for spraying devices with an extension unit, exhibiting a spray head with at least one material discharge nozzle at a first end and at its second end means to connect a spraying device. In addition, the present invention relates to a spraying device to spray material onto surfaces with an extension device. 
         [0003]    Spraying devices have been state of the art for a long time and are used in many different areas for the purpose of cleaning, disinfection, surface treatment or coating workpieces. The main structure of the spraying devices is essentially comprised of a base body with valves for the material to be sprayed, a material needle, a spray head with a material discharge nozzle, and possibly air nozzles, as well as an actuator to activate and terminate the spraying process. 
         [0004]    The materials to be sprayed are understood to be both liquid as well as paste-like media. Both highly as well as low-viscous spray material may be utilized. 
         [0005]    In order to adapt the diverse applications of the spraying devices to the different geometries and properties of workpieces, a number of adapters or extension devices are known to be positioned between the spray head and the base body of the spraying device. 
         [0006]    For example, an extension device with a rigid, straight spraying tube, also identified as a spray lance, is used for spraying trees, shrubs or the like as well as for industrial purposes, and is known from patent DE 1 005 783. The spray head of the jet tube is comprised of nozzles with valves, which are positioned with their valve plates ahead of the inlet openings of the nozzles. By rotating a rotatable body, the different nozzles located in the spray head can be controlled, whereby it is possible to adjust to different spraying modes. The side of the jet tube opposite the spray head can be mounted on the base body of the spraying device. 
         [0007]    A spray lance for a high-pressure cleaning device, wherein the spray lance is comprised of a hose with a nozzle and a support member, on which the hose is attached, is known from DE 20 2004 018 903 U1. Another embodiment provides a rigid tube, wherein the nozzle is positioned in a pivotable manner around a pivot axis transverse to its main spraying direction, specifically however, transverse to the longitudinal direction of the spray lance or the handle, instead of the hose. 
         [0008]    An extension device, which includes an extension tube, exhibiting its own control with hose connections at one end and a spray head with a material discharge nozzle on the other end, is known from DE 100 56 040 A1. The spray head comprises a material needle, which is controlled by means of compressed air and can be used to open and close the material discharge nozzle. Adjacent to the material discharge nozzle, nozzle horns with air nozzles are located on the spray head. The spray head is connected to the control device with the hoses located on the inside of the extension tube. 
         [0009]    This extension device has the disadvantage that an additional control device is required, particularly to actuate the material needle located in the spray head, and that the mechanical actuator usually located in the spraying device cannot be used directly. 
         [0010]    Furthermore, the spray head is clearly designed more elaborately due to the compressed air actuator means for the material needle. The manufacturing cost of the extension device is therefore overall more expensive than for extension devices, in which the material needle is guided from the spraying device to the material discharge nozzle through the extension tube. 
         [0011]    For example, such a device is known from DE-PS 585239. The spray head is constructed more plainly than with DE 100 56 040 A1, however, the length of the extension device is limited due to several factors. 
         [0012]    The material needle extending the entire length of the extension tube increases the total weight of the extension device, so that extension devices of several meters in length are no longer manageable. With such large lengths, the material needle will buckle and must be provided with additional support as necessary in the extension tube, not only further increasing weight, but also manufacturing cost. 
         [0013]    Another disadvantage lies therein that angled extension devices, for example, cannot be implemented without accepting additional disadvantages. The rigid material needle can be guided from the spraying device only to the bend in the extension tube, where another nozzle must then be positioned, with which the material needle interacts. Between this nozzle and the spray head positioned at the front end of the extension device, where the material exits through the actual material discharge nozzle, is potentially a large volume in the extension tube. After closing the nozzle by means of the material needle, material remains in this volume, which may discharge unintentionally through the constantly open material discharge nozzle. 
       SUMMARY OF THE INVENTION 
       [0014]    It is an object of the invention to provide an extension device, which distinguishes itself by a low weight and simple structure even at great lengths, wherein the amount of material to be sprayed, which may leak unintentionally, is to be minimized. 
         [0015]    The extension device is characterized in that the extension unit is comprised of a metering and shut-off valve exhibiting a valve seat member with a valve opening and a valve body, that the valve body is positioned between the spray head and the valve seat member and that the valve body is fastened to a tension-transmitting member, which extends through the valve opening. 
         [0016]    The metering and shut-off valve is preferably positioned within the extension unit, preferably in the first end of the extension unit or at the first end of the extension unit. 
         [0017]    The valve body is preferably located in front of the material discharge nozzle of the spray head. 
         [0018]    The valve body may extend into the spray head. The valve body does not interact with the material discharge nozzle. 
         [0019]    The metering and shut-off valve is preferably positioned in front of the spray head and thus in the flow direction of the material before the material discharge nozzle. 
         [0020]    Positioning the metering and shut-off valve as closely as possible in front of the spray head, respectively in front of the material discharge nozzle of the spray head, has the advantage that the space between the metering and shut-off valve and the material discharge nozzle can be kept small. The loss of material, respectively the remaining material, is therefore reduced considerably. 
         [0021]    If the metering and shut-off valve is positioned at the first end of the extension unit, the spray head is positioned at the first end of the extension unit and/or at the metering and shut-off valve. 
         [0022]    The metering and shut-off valve exhibits a valve seat member with a valve opening in interaction with a valve body. The conventional rigid material needle is replaced by the valve body and a tension-transmitting member attached thereto, wherein the valve body is located between the spray head and the valve seat member. The valve body is thus located between the material discharge nozzle and the valve opening. 
         [0023]    This arrangement is advantageous in that the pressure of the material to be sprayed can be used to open the metering and shut-off valve. The material pressed through the valve opening moves the valve body from the valve opening in the direction of material discharge nozzle, whereby the valve opening is opened. In order to close the valve opening, the valve body is pulled into the opposite direction by means of the tension-transmitting member. As the tension-transmitting member is required only to close the metering and shut-off valve, but not to open the metering and shut-off valve, it must not be rigidly constructed like a conventional material needle. This opens up the possibility for a simpler and particularly more flexibly designed tension-transmitting member, so that the extension unit can also be designed curved or bent. 
         [0024]    When retracting the valve body, the valve body moves increasingly closer to the valve seat member and finally closes the valve opening completely. Depending on the design of the metering and shut-off valve, the effective inner diameter of the throttle and shut-off valve may be altered by means of the tension-transmitting member by even slightly moving the valve body to the valve seat member, whereby the material flow can be controlled. As the tension-transmitting member is guided by the valve opening, the valve body is automatically pulled in front of the valve opening during the closing process, so that a tight seal is always guaranteed. 
         [0025]    In order to ensure that the spray material passes through the valve opening, the cross-section of the valve opening is greater than the cross-section of the tension-transmitting member. 
         [0026]    Opening the valve is accomplished by releasing or suspending the tractive forces acting on the tension-transmitting member. Due to the material pressure of the material located inside the extension device between the second end of the extension unit and the metering and shut-off valve, the valve body is pushed out of the valve seat member in the direction of the first end of the extension unit or pushed away from the valve seat member. The valve body is pushed as far in the direction of the first end of the extension unit as is possible with the maximum length of the tension-transmitting member. 
         [0027]    The tension-transmitting member can preferably be connected with a spraying device actuator located in the spraying device, which has the advantage that this device is utilized and additional actuators in the spray head, as is the case with state of the art according to DE 100 56 040 A1, are dispensable. The structure of the extension device is therefore further simplified, and manufacturing costs are kept low. 
         [0028]    Due to this connectivity, the tension-transmitting member can be comfortably operated via the spraying device. The actuator thus transfers tractive forces by means of the tension-transmitting member to the valve body. In addition, this connectivity offers the possibility of equipping a spraying device with various extension devices. Furthermore, a respective exchange of the extension device can be performed very quickly and inexpensively. 
         [0029]    In order to also transfer these tractive forces reliably, the tension-transmitting member is preferably soldered, welded or glued to the valve body. The connection may also be accomplished by means of clamping. 
         [0030]    The tension-transmitting member preferably consists of flexible material. 
         [0031]    The tension-transmitting member may also, for example, consist of a rope, cable, wire or a chain. 
         [0032]    The tension-transmitting member may exhibit significantly lower material cross-sections than is the case with a conventional material needle, as the tension-transmitting member is subjected to tensile stress only during tension. This has the advantage that weight is saved and that extension devices, exhibiting a length of several meters, are still manageable. The extension unit preferably exhibits a length of at least 0.5 m, specifically at least 1 m or at least 2 m. The extension unit may exhibit a length of 5 m or even up to 10 m. 
         [0033]    The tension-transmitting member enables force transmission between the second end of the extension unit and the valve body, regardless of the shape of the extension unit, i.e. regardless whether the extension unit exhibits curves, or is constructed straight. 
         [0034]    A flexible, i.e. bendable, tension-transmitting member adapts to any form of extension unit without being limited in its function. In order to be able to ensure the function of the tension-transmitting member pulling the valve body in the axial direction of the extension unit in the direction of the second end of the extension unit, its flexibility must not apply to the axial direction of the extension unit. 
         [0035]    By using, for example, a cable or rope, the flexibility of the tension-transmitting member can be accomplished in a simple, inexpensive and practical manner. Furthermore, it is very easy to lay a rope or cable through the extension unit of the extension device, specifically if the extension unit exhibits curvatures. 
         [0036]    The tension-transmitting member consists advantageously at least partially of metal or an alloy or plastic, or a combination thereof. 
         [0037]    Tension-transmitting members made from these materials exhibit good flexibility in the radial direction and very little flexibility in the axial direction depending on their diameter and are therefore very suitable for the transmission of tractive forces. In addition, by selecting different materials, the tension-transmitting member can be adapted to the respective requirements. For example, metals or alloys exhibit increased long-term stability, while plastics may be resistant to acidic or alkaline spray materials. 
         [0038]    In another advantageous embodiment of the extension device according to the invention, the extension unit is at least partially curved. 
         [0039]    The degree of curvature may be chosen arbitrarily. The extension unit may have only one curvature or even several curvatures that are provided consecutively. The term curvature here means any deviation from a straight line. 
         [0040]    By means of an extension unit with at least partial curvature, the extension device can be adapted to different workpieces to be treated. By selecting appropriate curvatures, even undercuts or cavities of workpieces can be reached with the first end of the extension unit and be treated or coated with spray material. Due to the flexibility of the tension-transmitting member, the tension-transmitting member accordingly aligns with the respective curvatures of the extension unit. 
         [0041]    The extension unit preferably consists of a pliable, preferably ductile material, and/or the extension unit is comprised of at least one pliable section. Ductile material can be metals, alloys or plastics. Pliable sections can be positioned between non-pliable sections. Such pliable sections may consist of pliable materials or even of a bellows-like structure. At the curved location, such bellows-like or accordion-like sections are preferably dimensionally stabile, specifically dimensionally stabile as it pertains to their diameter. 
         [0042]    In a first embodiment, the valve seat member is an annular disc and the valve body a valve plate. 
         [0043]    Annular discs and valve plates are inexpensive workpieces, which, in addition, can be easily positioned in the extension unit. 
         [0044]    An annular disc can be made with different opening diameters, which, in addition, can be positioned centrally or peripherally inside the annular disc. By using an annular disc as the valve seat member, the option of adapting same to the different requirement features of the extension device is therefore attained. 
         [0045]    According to a further embodiment, the valve seat member and the valve body each exhibit a cone-like or frustoconical shape. 
         [0046]    A cone-like or frustoconical valve body, whose cross-section tapers in the direction of the second end of the extension unit, is a streamlined valve body. So configured, turbulences of the spray material flowing past the valve body are greatly reduced. Thus a homogenous and constant material discharge from the first end of the extension device is ensured. 
         [0047]    The valve seat member preferably exhibits a first conical surface and the valve body a second conical surface. The conical surfaces are adapted to each other such that the valve body in the closed position abuts with its second conical surface against the first conical surface. Outside of a good seal in the closed position of the valve body, the valve body is centered by the interaction of the conical surfaces during the closing process. A tilting of the valve body is thereby prevented. 
         [0048]    In one advantageous embodiment, the valve body is at least partially comprised of metal or an alloy or plastic, or a combination of these materials. 
         [0049]    As already described in the context of material properties of the tension-transmitting member, the valve body can also be adapted to different requirement profiles of the extension device by selecting different materials. For example, valve bodies made of metal exhibit an increased lifespan, while valve bodies made of plastic are more cost-effective and lighter. 
         [0050]    In another advantageous embodiment, the extension device exhibits at least one hole and/or at least one groove. These grooves and holes preferably extend in the longitudinal direction of the extension unit. Holes and/or grooves have the advantage that when the valve body is in the open position, space is created for spray material to pass through. 
         [0051]    The outer cross-sectional dimensions of the valve body can be adapted to the dimensions of the inner cross-section of the extension unit such that the valve body is guided inside the extension unit. In this embodiment, while the valve body is in the open position, the spray material flows exclusively through the holes and/or grooves, whereby the grooves are preferably positioned in the outer circumferential surface of the valve body. 
         [0052]    The outer cross-sectional dimensions of the valve body may be lower than the dimensions of the inner cross-section of the extension unit. In this embodiment, the valve body is not guided, however there is an advantage in that sufficient space is available between the valve body and the wall of the extension unit to allow spray material to pass. The holes and/or grooves form an additional space for the spray material to pass, which is specifically important in the use of highly viscous materials. 
         [0053]    Holes and/or grooves have an additional advantage in that the volume flow of the spray material intended to pass through the valve opening can be additionally adjusted. Also, the risks of possibly occurring clogs at the throttle and shut-off valve are reduced by providing holes or grooves. 
         [0054]    A material guide element is preferably positioned in front of the valve opening in the direction of the flow of the material to be sprayed. The material guide element directs the material flow to the valve opening, whereby dead spaces are avoided in the area in front of the metering and shut-off valve, and the flow of the material is promoted. The material guide element is preferably an integral component of the valve seat member. 
         [0055]    The material guide element is preferably shaped in a frustoconical manner or has a conical inner surface. Thus, a conical cavity is formed in the material guide element, tapering toward the valve opening. 
         [0056]    In an advantageous embodiment of the extension device, the extension unit is a tube. 
         [0057]    An extension unit made as a tube is cost efficient and can be made fast. Tubes may exhibit different wall thicknesses, diameters and cross-sections, whereby the extension unit can be adapted to many different spray materials and workpieces to be treated. The tube preferably exhibits a circular cross-section, whereby non-rotational passage of the spray material through the extension unit is promoted. 
         [0058]    Preferably at least one compressed air line, which can be positioned inside or outside of the extension unit, is provided. 
         [0059]    In order to form a beam, the spray head exhibits at least one air nozzle, which can be connected to the compressed air line. 
         [0060]    The extension unit is preferably made with double walls. The extension unit preferably exhibits an inner and an outer wall. 
         [0061]    The inner wall and the outer wall are preferably positioned at least partially spaced apart from each other, specifically completely spaced apart, so that a compressed air line is formed. To completely space apart walls means that the walls are positioned spaced apart over the entire length of the extension unit. 
         [0062]    The inner wall and the outer wall are preferably positioned coaxially. 
         [0063]    The outer wall is preferably a hose. A hose has the advantage that it can easily be pushed via the wall of the extension unit. Partial contact of the hose with the wall cannot be excluded with curved extension units. In this instance, partially spaced positioning of the two walls is the case. 
         [0064]    The invention also relates to a spraying device for spraying spray materials onto surfaces, whereby an extension device according to the invention is provided. 
         [0065]    This spraying device exhibits the same advantages previously discussed in the context with the extension device according to the invention. 
         [0066]    In an advantageous embodiment of the spraying device, the actuator is connected to the tension-transmitting member of the extension device. 
         [0067]    In another advantageous embodiment of the spraying device, the actuator exhibits a movable plunger and a spring device. This plunger is preferably positioned in a manner accommodating retracting and extending. The tension-transmitting member is preferably attached to the plunger. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0068]      FIGS. 1 a, b    Sectional illustrations of the extension unit with a spraying device according to a first embodiment with a metering and shut-off valve in open and closed positions, 
           [0069]      FIG. 2  an extension unit with a spraying device according to a second embodiment, 
           [0070]      FIG. 3 a - c    enlarged sectional illustrations of the first end of an extension unit with metering and shut-off valves according to three additional embodiments, 
           [0071]      FIG. 4  a sectional illustration of an extension unit with a spraying device and a metering and shut-off valve according to  FIG. 1 a, b    and a spray head according to another embodiment, 
           [0072]      FIG. 5  a sectional illustration of an extension device with a spraying device according to another embodiment and 
           [0073]      FIG. 6  a detailed illustration of the first end of the extension unit according to  FIG. 5 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0074]      FIG. 1 a    is an extension device  10  shown in longitudinal section, connected at its second end  16  to spraying device  1  by means of fastening devices  18 , which may, for example, exhibit a screw thread. Spraying device  1  is depicted schematically in  FIG. 1 . 
         [0075]    At its first end  14 , extension unit  12  shows a spray head  40 , which exhibits a material discharge nozzle  42 . The embodiment shown here shows spray head  40  shaped cone-like and exhibiting a conical inner surface  45 . Spray head  40  may be attached to extension unit  12  in a releasable manner, e.g. by means of a screw thread, or may be fastened in a non-releasable manner, e.g. by soldering. 
         [0076]    A metering and shut-off valve  20 , which exhibits a valve seat member  22  with valve opening  24 , is positioned at first end  14  inside extension unit  12 . Between spray head  40  and thus between material discharge nozzle  42  and the valve seat member  22 , is an intermediate space  44 , inside which is valve body  26 , at which tension-transmitting member  28  is attached. Tension-transmitting member  28  consists of flexible material and can, for example, be a rope and extends from valve body  26  through valve opening  24 . The diameter of valve opening  24  is greater than the diameter of tension-transmitting member  28 . Furthermore, the diameter of valve opening  24  is smaller than the largest diameter of valve body  26 . 
         [0077]    Tension-transmitting member  28  extends to the second end  16  of extension unit  12  and reaches into spraying device  1 , where tension-transmitting member  28  is connected to actuator  2  of spraying device  1 . 
         [0078]    This actuator  2  is depicted schematically and exhibits a movable plunger  3 , which interacts with spring device  4 . Tension-transmitting member  28  is fastened to plunger  3 . 
         [0079]      FIG. 1 a    illustrates how valve body  26  is pushed against valve seat member  22  by means of spring device  4  interacting with tension-transmitting member  28  and held there. Consequently, valve opening  24  is closed by valve body  26 . In this position, spray material cannot pass from extension unit  12  to spray head  40  through valve opening  24 . 
         [0080]    In order to open valve opening  24 , plunger  3  is preferably moved back by means of compressed air against the force of spring device  4 , whereby tension-transmitting member  28  is relieved. The pressure of the material pressed into extension unit  12  is sufficient to move valve body  26  into the open position (see  FIG. 1 b   ). 
         [0081]    The material to be sprayed is introduced into extension unit  12  by spraying device  1  and flows in arrow direction through extension unit  12  to valve opening  24 . The material pressed through valve opening  24  moves valve body  26  from valve seat member  22  in the direction of spray head  40 , when tension-transmitting member  28  is relieving tension. 
         [0082]    The material to be sprayed subsequently passes into intermediate space  44  and can be discharged by material discharge nozzle  42 . 
         [0083]    Valve seat member  22  is shaped like a cone and exhibits a first conical surface  23  on its inside. Valve body  26  exhibits a second conical surface  27 , which is adapted to the first conical surface  23 . The diameter of valve body  26  is smaller than the inside diameter of extension unit  12  shaped like a circular tube, so that sufficient space is available between valve body  26  and the tube&#39;s wall for spray material to pass. 
         [0084]    By activating actuator  2 , the tension-transmitting member can be retracted such that valve body  26  abuts first conical surface  23  of valve seat member  22  with its second conical surface  27  and thus closes valve opening  24 . Depending on how far valve body  26  is pulled in the direction of valve opening  24  by means of actuator  2 , material flow can be controlled by valve opening  24 . 
         [0085]      FIG. 2  depicts another embodiment, which illustrates a curved extension unit  12 . The curvature, i.e. the deviation from the longitudinal axis L S  of spraying device  1 , amounts to 90° in this embodiment. Since tension-transmitting member  28  is a flexible element, tension-transmitting member  28  adapts to extension unit  12 &#39;s 90° curvature shown here. The way metering and shut-off valve  20  functions, is the same as in the embodiment of  FIGS. 1 a  and  b   . Extension unit  12  may also exhibit several arbitrary curvatures. The length of the extension unit  12  may be several meters. Lengths up to 10 m are possible. 
         [0086]    In addition, material guide element  30  is positioned at valve seat member  22 , which is shaped cone-like in the embodiment shown here and has a conical inner surface  31 . 
         [0087]    Material guide element  30  tapers in the direction of valve opening  24 , so that the incoming material is directed to valve opening  24 . As a result, dead spaces in the area of valve seat member  22  are avoided, in which the material to be sprayed could dam up and deposit. 
         [0088]    In  FIG. 3 a   , another embodiment of the metering and shut-off valve  20  is illustrated. Valve seat member  22  is comprised of an annular disc and valve body  26  of a valve plate. In order to improve the material flow in the open position of metering and shut-off valve  20 , the valve plate additionally exhibits holes  32 . 
         [0089]      FIG. 3 b    depicts another embodiment of the metering and shut-off valve  20 , wherein the outer diameter of valve body  26  essentially corresponds to the inner diameter of extension unit  12 , so that valve body  26  is guided by extension unit  12 . In order to enable material flow in the direction of material discharge nozzle  42 , valve body  26  has at its outer peripheral surface grooves  34 , which extend parallel to longitudinal axis L of spray head  40 . 
         [0090]    Holes  32  and grooves  34  may also be combined in valve body  26 . 
         [0091]      FIG. 3 c    illustrates another embodiment, wherein metering and shut-off valve  30  is positioned at the first end  14  of extension unit  12 . Spray head  40  is located at metering and shut-off valve  20 . 
         [0092]    Valve seat member  20  is connected in a detachable manner with extension unit  12 , and spray head  40  is connected in a detachable manner with valve seat member  22 . The combination of valve seat member  22  and extension unit  12  is, for example, accomplished by means of screw connection  21 , whereas the connection between valve seat member  22  and spray head  40  is accomplished by means of a plug-in connection  41 , or a clamping connection. 
         [0093]    For this plug-in connection  41 , a sleeve-like tube is positioned on spray head  40 . Material guide element  30  exhibits a conical inner surface  31 , whereby a cavity is formed, which tapers toward valve opening  24 . Valve element  22  exhibits a first conical surface  23 , which is adapted to the second conical surface  27  of valve body  26 . 
         [0094]    A sleeve-like section  29  attaches to the first conical surface  23 , which extends in the direction of spray head  40 . 
         [0095]    Valve body  26  is shaped in a cylindrical manner and has a smaller diameter than the inner diameter of the sleeve-like section  29 . At its end facing spray head  40 , valve body  26  has a cone-like tip  27   a  with which valve body  26  extends into spray head  40  in its open position. Spray head  40  abuts the front surface  29   a  of sleeve-like section  29 . A cone-like intermediate space  44  is formed between the conical inner surface  45  of spray head  40  and the cone-like tip  27   a  of valve body  26 . Intermediate space  44  remains, even if valve body  26  is located at its maximum distance to conical surface  23 . 
         [0096]      FIG. 4  illustrates another embodiment, in which extension unit  12  is designed with double walls. Extension unit  12  exhibits an inner wall  50  and an outer wall  52 , whereby both walls are positioned spaced apart from each other such that between inner wall  50  and outer wall  52  a compressed air line  54  can be formed in the shape of an annular channel, as can be seen in the enlarged detail illustration of  FIG. 6 . Respective connections (not depicted) are provided in spraying device  1  in order to be able to introduce compressed air into this channel. 
         [0097]    Outer wall  52  is preferably formed by a hose pushed over inner wall  50 , which may consist of a metal tube. 
         [0098]    Spray head  40  exhibits horns  46  with air nozzles  48 . Compressed air line  54  is connected to these air nozzles  48  by means of air duct  49 , so that forming a beam of spray material with different beam geometries can be accomplished. 
         [0099]      FIG. 5  illustrates another embodiment, in which extension unit  12  is also shaped with double walls and, in addition, exhibits two curvatures. The double-walled embodiment of extension unit  12  is shaped such that regardless of the curvatures, the inner wall  50  and outer wall  52  are always positioned spaced apart to each other, so that between the two walls compressed air line  54  can be formed in the shape of an annular and curved channel. 
         [0100]    In this embodiment, spray head  40  also exhibits horns  46  with air nozzles  48 . Compressed air line  54  is connected to these air nozzles  48 , so that forming a beam of spray material with different beam geometries can be achieved. 
         [0101]      FIG. 6  is a detailed illustration of the first end  14  of extension unit  12  shown in  FIG. 5 . Valve seat member  22  of the metering and shut-off valve  20 , corresponding to the embodiment in  FIG. 3 c   , is connected in a detachable manner to extension unit  12 , and spray head  40  is connected in a detachable manner with valve seat member  22 . Valve body  26  with tension-transmitting member  28  also corresponds to the embodiment of  FIG. 3 c   . The connection of valve seat member  22  and extension unit  12  is again made by means of screw connection  21 , whereas the connection between valve seat member  22  and spray head  40  is achieved by a simple plug-in and/or clamping connection  41 . 
         [0102]    With this embodiment as well, a sleeve-like section  47  is positioned on spray head  40  for the plug-in and/or clamping connection  41 . 
         [0103]    Spray head  40  exhibits two horns  46  with air nozzles  48 , which are positioned in the direction of material flow behind the material discharge nozzle  42 . Furthermore, extension unit  12  is designed with double walls, whereby the compressed air line  54  leads to spray head  40 &#39;s air ducts  49 , at whose ends are air nozzles  48 . Air ducts  49   a , which lead to material channel  42   a , positioned ahead of material discharge nozzle  42 , branch off from air ducts  49 . Thus, forming a beam with different beam geometries can be achieved. 
         [0104]    By means of clamping connection  43 , outer wall  52  is connected in a detachable manner with spray head  40  and closes compressed air line  54  with an airtight seal. The sleeve-like section  47  is positioned between end section  53  of outer wall  52  and sleeve-like section  29  of valve element  22 . The spray head exhibits a conical inner surface  45  similar to  FIG. 3   c.    
       REFERENCE LIST 
       [0000]    
       
         
           
               1  Spraying device 
               2  Actuator 
               3  Plunger 
               4  Spring device 
               10  Extension device 
               12  Extension unit 
               14  First end 
               16  Second end 
               18  Fastening devices 
               20  Metering and shut-off valve 
               21  Screw connection 
               22  Valve seat member 
               23  First conical surface 
               24  Valve opening 
               26  Valve body 
               27  Second conical surface 
               27   a  Tip 
               28  Tension-transmitting member 
               29  Sleeve-like section 
               29   a  Front surface 
               30  Material guide element 
               31  Inner surface 
               32  Hole 
               34  Groove 
               40  Spray head 
               41  Plug-in connection 
               42  Material discharge nozzle 
               42   a  Material channel 
               43  Clamping connection 
               44  Intermediate space 
               45  Inner surface 
               46  Horn 
               47  Sleeve-like section 
               48  Air nozzle 
               49  Air duct 
               49   a  Air duct 
               50  Inner wall 
               52  Outer wall 
               53  End section 
               54  Compressed air line 
             L Longitudinal axis 
             L s  Longitudinal axis of the spraying device