Abstract:
A spraying apparatus ( 19 ) for an agricultural field sprayer ( 10 ) having at least one spray line ( 32 ) disposed on the spraying boom ( 20 ), and a plurality of discharge openings ( 36 ) disposed along the spray line ( 32 ) connected by a part ( 38 ) to an inlet opening ( 66, 76 ) of a spray nozzle body ( 40, 70 ). Fluid flow from the inlet opening ( 44 ) to the nozzle body inlet opening ( 66, 76 ) is along a straight line fluid path. The connecting part ( 38 ) is configured as a valve housing. A ball ( 54 ) is responsive to a magnetic field generated by a coil ( 52,68 ) for movement away from a closed position located generally on the straight line fluid path to an open position offset from the path.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a spraying apparatus for an agricultural field sprayer having a spraying boom, a spray line disposed on the spraying boom, and a plurality of discharge openings for spray liquid. The openings are disposed along the spray line and are respectively connected to an inlet opening of a spray nozzle body by way of a connecting part. This invention also relates to an agricultural field sprayer having such a spraying apparatus. 
       BACKGROUND 
       [0002]    Spraying apparatuses for agricultural field sprayers, in which a spray line is mounted on a foldable or hinged or retractable and extensible boom, are known. The boom is generally fastened to the frame of the vehicle and is transported over the ground, by means of the vehicle, for the application of spray liquid. The spray line has a plurality of discharge openings, which are provided with connecting bodies. The connecting bodies connect the spray line to a valve and a spray nozzle housing, and the spray liquid to be applied is routed from the spray line into the spray nozzle body by actuation of the valve. The spray nozzle body is equipped with one or more spray nozzles to ensure an appropriate atomization of the spray liquid during application. The connecting bodies, which are generally configured as a T-joint, are connected to the spray line on an upper connecting part having the respective discharge openings of the spray line. Lower connecting parts are connected to the spray nozzle bodies. A further connecting part, to which the valve controlling the flow of a spray liquid is connected, extends laterally. The spray liquid is thus first conducted from the upper connecting part into the lateral connecting part of the connecting body. From the lateral connecting part, the spray liquid flows into the valve body and into the spray nozzle body via the lower connecting part. Spraying apparatuses of this type are marketed, for example, by the company HYPRO, and may be equipped with pneumatically controlled stem-actuated valves, whereby a spring-loaded control piston, which correspondingly opens and closes a discharge opening in the valve, is moved pneumatically. 
         [0003]    A further spraying apparatus of this type is disclosed in EP 0932448, which differs from the above-described spray apparatus by virtue of the fact that the control piston can be actuated electromagnetically. Both of these arrangements have the drawback that the spray liquid, as it flows through the connecting body or the valve, undergoes several changes of direction which leads to flow losses. In addition, the section through which the spray liquid passes, in particular the section from the discharge opening in the valve to the inlet into the spray nozzle body, is relatively long. Therefore, upon valve closure, considerable residue of spray liquid continues to flow after the closure, which can result in uncontrolled dripping in the application of the spray product. Furthermore, the valves which are used prove to be costly and complicated. 
       SUMMARY 
       [0004]    An object of the invention may be a spraying apparatus of the type stated in the introduction, by which one or more of the abovementioned problems may be overcome. 
         [0005]    The object is achieved according to the invention by the teaching of patent claim  1  with further advantageous embodiments and refinements of the invention emerging from the claims dependent therefrom. 
         [0006]    According to the invention, a spraying apparatus of the type stated in the above introduction is configured such that the connecting part is configured as a valve housing and has an inlet opening and an outlet opening for spray liquid. The outlet opening may be closed by a valve control structure. The inlet opening and the outlet opening of the connecting part are located opposite each other, and the direction of flow from the inlet opening to the outlet opening continues in the same direction to the inlet opening of the spray nozzle body. The fact that the connecting part is itself configured as a valve housing reduces the multiplicity of parts of the spraying apparatus. The two originally used components, namely a connecting part configured as a T-joint which connects the spray line and the spray nozzle body, and a valve housing which was fastened to the connecting part, are reduced to just one component. In addition, the path covered by the spray liquid from the discharge opening of the spray line to the inlet opening of the spray nozzle body is able to be made more compact. The fact that the inlet opening and the outlet opening of the connecting part configured as a valve housing are disposed opposite each other and the outlet opening is flowed through by the spray liquid in the same direction of flow as the inlet opening of the spray nozzle body enables the spray liquid, as it flows through the connecting part, to follow a direct path. Compared to a traditional connecting part configured as a T-joint wherein alternating directions of flow of the spray liquid occur, flow losses are reduced. Furthermore, a spraying apparatus according to the invention allows the outlet opening to be disposed in the direct vicinity of, or in comparison to traditional configurations having a T-joint, substantially closer to the inlet opening of the spray nozzle body. Residual flow of spray liquid is thereby virtually prevented when the outlet opening is closed by the valve control means since the distance or spacing between the outlet opening of the valve housing and the inlet opening of the spray nozzle body is minimized to minimize residual spray liquid present in the line portion between the outlet opening and the inlet opening of the spray nozzle body. The structure leads to a marked reduction in drip formation following closure of the outlet opening of the valve housing, since, in the traditional variant having a connecting part configured as a T-joint, the line portion configured between the outlet opening of the valve housing and the inlet opening of the spray nozzle body is substantially longer and thus contains significantly more residual spray liquid. 
         [0007]    In one embodiment of the invention, the connecting part comprises an electromagnetic coil and the valve control means is configured as a magnetizable ball, that is, a ball made of or including material that may be attracted or repulsed by a magnetic field. The coil is configured and disposed such that, when the coil is electrically energized, the ball can be moved out of a closing position to an open position. In the closed position, the outlet opening is closed by the ball, and in the open position the ball may be moved transversely to the direction of flow of the spray liquid away from the outlet opening. The ball is arranged and dimensioned such that it covers or closes off the entire flow cross section of the outlet opening of the connecting part configured as a valve housing. Therefore, when pressure is applied to the spraying apparatus, the ball is forced into the outlet opening by the pressure difference between the inlet opening and the outlet opening to close the outlet opening. By electrically energizing the coil, a magnetic flux and thus a magnetic force can be generated which moves the magnetizable ball out of its seat. When the electrical energization of the coil is terminated, the ball is automatically forced back into the outlet opening due to the abovementioned hydraulic pressure difference. The connecting part configured as a valve housing, together with the coil and the valve control means configured as a ball, thus constitutes a type of ball valve, the seat of the ball constituting a valve seat configured on the outlet opening. An appropriate layout, geometry, positioning and orientation of the coil enables the generated magnetic force acting upon the ball to be orientated such that the ball is moved laterally or transversely to the direction of flow. 
         [0008]    The connecting part may be configured as a hollow body, with the coil being configured over an entire peripheral region of the hollow body such that the rotational axis of symmetry of the coil points in the direction of flow of the spray liquid and the ball is located inside the coil. The hollow body can be configured, for example, as a tube or hollow cylinder having an inlet opening and an outlet opening, the outlet opening being blockable by a ball mounted in the hollow cylinder. The tube or hollow cylinder is surrounded on its periphery by the coil having a winding of configured on or in the wall of the tube or hollow cylinder. The winding is encased by a magnetizable material. A non-magnetizable region in this casing, or an opening or interruption of the casing, is provided from which the magnetic field lines generated upon energization of the coil can emerge or enter and exert a magnetic force on the ball mounted inside the tube or hollow cylinder. By appropriate shaping of the winding and of the non-magnetizable region on the casing of the winding (or of the interruption or opening on the casing of the winding), the direction of action of the generated magnetic force can be varied, so that the magnetic force is able to move the ball out of its seat in a direction transversely to the outlet opening of the tube or hollow cylinder. 
         [0009]    In an alternative embodiment of the invention, the connecting part is configured as a hollow body and the coil is configured in or on a region of the wall of the hollow body such that the rotational axis of symmetry of the coil points transversely to the direction of flow of the spray liquid and the ball is located outside the coil. The hollow body may be configured, for example, as a tube or hollow cylinder having an inlet opening and an outlet opening, the outlet opening being blockable by a ball mounted in the hollow cylinder. The tube or hollow cylinder can be formed of a non-ferromagnetic metal with an electromagnetic coil being embedded or incorporated, for example, in the wall of the hollow cylinder, level with the ball seat. The electromagnetic coil when energized exerts a corresponding magnetic force on the ball and moves this out of its seat in a direction transversely to the outlet opening of the tube. 
         [0010]    The connecting part may be connected to the spray line directly at the discharge opening of the spray line. The connecting part configured as a tube or hollow cylinder, or the valve housing configured as a tube or hollow cylinder, can thus be directly fastened with its inlet opening to the discharge opening of the spray line, for example by a screw thread, by a plug connection, by bonding, or by a bayonet fastening. 
         [0011]    The connecting part is connected directly at its outlet opening to the inlet opening of the spray nozzle body. A connecting part configured as a tube or hollow cylinder, or the valve housing configured as a tube or hollow cylinder, can thus connect to the inlet opening of the spray nozzle body, for example by a screw thread, by a plug connection, by bonding, or by a bayonet fastening. By virtue of the fact that the outlet opening of the connecting part and the inlet opening of the spray nozzle body lie as close together as possible, the quantity of spray liquid which, upon closure of the connecting region configured as a valve housing, afterflows into the spray nozzle body is able to be reduced or minimized. The spray nozzle body can here be formed as a traditional spray nozzle body with or without a spray nozzle carousel for nozzle selection. 
         [0012]    In an embodiment of the invention, the spraying apparatus is configured such that the direction of flow of the spray liquid through the discharge opening of the spray line, through the inlet opening of the connecting part, through the outlet opening of the connecting part and through the inlet opening of the spray nozzle body is the same or remains constant so that the flow of the spray liquid from the discharge opening of the spray line into the inlet opening of the spray nozzle body can be realized without significant changes of direction. The connecting part configured as a valve housing can be configured, for example, as a tubular or hollow cylinder having opposing inlet and outlet openings, the inlet opening lying in alignment with the discharge opening of the spray line and the outlet opening lying in alignment with the inlet opening of the spray nozzle body, so that, as far as possible, rectilinear flow of spray liquid is ensured. Flow losses generated by changes of flow direction can hence be avoided or minimized. 
         [0013]    In one embodiment of the invention, an agricultural field sprayer, equipped with a spraying apparatus according to the above description, is provided and has a plurality of discharge openings and a plurality of connecting parts configured as valve bodies connected to a corresponding plurality of spray nozzle bodies. 
         [0014]    It is of particular advantage that, as a result of the arrangement according to the invention compared with traditional electrically or pneumatically controlled valve devices with T-joint-like connecting pieces, the distance between a discharge opening on the spray line and the inlet opening of a spray nozzle body can be significantly reduced, whereby a fall in pressure in the spray liquid in this region is reduced, enabling the spray liquid to be applied in a more effective, precise and uniform manner. As a result of the ball-valve-like configuration of the connecting part configured as a valve body, any potential for blockage of the valve body is further minimized, since the movement of the ball has a self-cleaning effect. 
         [0015]    The invention, and further advantages and advantageous refinements and embodiments of the invention, are described and explained in greater detail below with reference to the drawing, which shows two illustrative embodiments of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  shows a schematic side view of an agricultural field sprayer having a spraying apparatus according to the invention, 
           [0017]      FIG. 2  shows an enlarged cross-sectional view of a connecting part of the spraying arrangement from  FIG. 1  in a first illustrative embodiment, 
           [0018]      FIG. 3  shows an enlarged cross-sectional view of a connecting part of the spraying arrangement from  FIG. 1  in a second illustrative embodiment, and 
           [0019]      FIG. 4  shows an enlarged cross-sectional view of the connecting part of the spraying arrangement according to  FIG. 3 , with a spray nozzle body having a spray nozzle carousel. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]      FIG. 1  shows an agricultural sprayer  10  in the form of a trailer sprayer towed by a tractor  12 . The sprayer  10  has a frame  14  with wheels  16 . Fitted to the frame  14  is a parallelogram linkage  18 , to which a spraying apparatus  19  is connected. The spraying apparatus  19  comprises a spraying boom  20 . In addition, the sprayer  10  is provided with a tank  22  fitted to the frame  14 . 
         [0021]    The spraying boom  20  has top and bottom members  24 ,  26 , which are connected to each other by numerous diagonal members  28  and form a framework. The spraying boom  20  is made up of a plurality of segments  29 ,  30 , which are connected to each other by hinges  31  and extend on both sides of the sprayer  10 . As a result of the hinges  31 , the spraying boom  20  can be collapsed into a transport position (as represented in  FIG. 1 ) or into an operating position. 
         [0022]    The spraying boom  20  is provided with spray lines  32  which extend on both sides of the sprayer  10  along the spraying boom  20 . The spray lines  32  are configured at least partially as tubes, which are provided with discharge openings  36 . The spray lines  32  are connected to supply and return hoses (not shown), by which a spray liquid to be sprayed is conducted from the tank  22  into the spray line  32 , or non-applied (unsprayed) spray liquid is conducted in a recirculating manner from the spray line  32  back to the tank  22 . 
         [0023]    In one embodiment of the spraying apparatus  19  illustrated in  FIG. 2 , the discharge openings  36  of the spray line  32  are provided with a connecting part  38  and a spray nozzle body  40  connected to the connecting part  38 . The spray nozzle body  40  is further equipped with a spray nozzle  42 . 
         [0024]    The connecting part  38  comprises an inlet opening  44 , an outlet opening  46 , and a mounting flange  48 , which is sealed off by means of an O-ring  50 . The connecting part  38  further comprises an electromagnetic coil  52 . Inside the connecting part  38  there is disposed a magnetizable ball  54 , which blocks the outlet opening  46 . The connecting part is shown as being configured in a rotationally symmetric manner as a tube or as a hollow cylinder. In a cavity  55  of the connecting part  38 , a step surface  56  is provided between the inlet opening  44  and the outlet opening  46 . The ball  54 , the outlet opening  46 , the step surface  56  and the inlet opening  44  are dimensioned or coordinated such that, on the one hand, the diameter of the ball  54  is larger than the diameter of the outlet opening  46  and, on the other hand, the step surface  56  is large enough to enable the ball  54  to be mounted thereon without blocking the outlet opening  46  once the outlet opening  46  is cleared of the ball  54 . The lower region of the connecting part  38  is configured as a mounting flange  58 , to which the spray nozzle body  40  is fastened, the step surface  56  being configured on that side of the mounting flange  58  which is facing the cavity  55 . The coil  52  has a wire winding  60  and a magnetizable casing  62  of the wire winding  60 , the casing  62  having a non-magnetizable region  64  or an opening or interruption of the casing  62  for the issue of magnetic field lines  65 . The coil  52  is configured as a sleeve or tube, so that it is pushed with its cavity over the outer surface of the connecting part  38 . The non-magnetizable region  64  of the casing  62  is here orientated such that it lies level with the ball  54 , so that the magnetic field lines  65  which, when the coil  52  is energized, emerge from the non-magnetizable region exert a magnetic force which is directly transmitted to the ball. Through energization of the coil  52 , the ball is then moved to the side by means of the generated magnetic force, i.e. perpendicularly to the direction of flow of the spray liquid flowing through the connecting part  38 , so the outlet opening  46  is cleared. 
         [0025]    The inlet opening  44  and the outlet opening  46  are arranged such that they flow passes therebetween in a same direction. The cavity  55  inside the connecting part  38 , which is accessible through the inlet opening  44 , passes directly into the outlet opening  46  so that no further partitions are provided so that, as far as possible, direct flow of fluid occurs without changes of direction. The spray nozzle body  40  has an inlet opening  66 , which directly connects to the outlet opening  46  of the connecting part  38  in the region of the mounting flange  58 , the same direction of flow being maintained here also. The spray nozzle body  40  is in this case configured as a single-nozzle body, having just one exchangeable spray nozzle  42 . 
         [0026]    The coil can be energized on a frequency-dependent basis by a programmed electronic control unit (not shown), so that, in the presence of a voltage, a magnetic field is generated, by which the ball  54  is moved to the side onto the annular surface of the step  56 , and, in the absence of a voltage, the magnetic field is deactivated, so that the ball is forced by the through-passing spray liquid into its ball seat. In other words, the ball is pressed into the outlet opening  46  to block flow. Through appropriate clocked or frequented or pulsed or pulse-width modulated energization of the coil, an opening and closing of the outlet opening  46  can be precisely controlled. The connecting part  38  thus constitutes a valve body comprising a valve control means configured as a ball  54 . The ball  54  and the outlet opening  46  disposed in the connecting part  38  or in the valve body, defines a ball valve which can be controlled or opened electromagnetically by energization of the coil  52 . Advantageously, due to the compact configuration of the connecting part  38 , a very short spacing between the outlet opening  46  of the connecting part  38  and the inlet opening  66  of the spray nozzle body  40  is realized, whereby the residual or afterflow of spray liquid present between the outlet opening  46  and the inlet opening  66 , and thus also a drip formation on the spray nozzle  42 , occurring upon closure of the valve body, is minimized or reduced. 
         [0027]    An alternative embodiment represented in  FIG. 3  is similar to the embodiment represented in  FIG. 2  but includes a different type and arrangement of the coil  68  which magnetizes the ball  54 . The coil  68  of the  FIG. 3  embodiment is configured as a traditional electromagnetic coil  68  without magnetizable casing  62 . The coil  68  is level with the ball  54  and is flush-mounted into the wall of the connecting part  38 . The coil diameter is relatively small compared that of the embodiment shown in  FIG. 2 . The magnetic force generated by energization of the coil  68  acts longitudinally to the coil axis. Through appropriate geometric configuration of the coil  68  with respect to diameter, length, number of windings and coil wire thickness, various magnetizations, and thus variously high magnetic forces, can be obtained. The energization of the coil  68  is realized in the same way as in the illustrative embodiment represented in  FIG. 2 . All other details and particulars apply correspondingly according to the embodiment described above in relation to  FIG. 2 . 
         [0028]    Even though the invention has been described on the basis of several illustrative embodiments, in the light of the above description and the drawing many other diverse alternatives, modifications and variants which fall under the present invention will be revealed to the person skilled in the art. For instance, in a further embodiment as represented in  FIG. 4 , in place of a single-nozzle body, a spray nozzle body  70  having a plurality of spray nozzles  72  can be connected. The spray nozzles are in this case disposed on a spray nozzle carousel  74 , which is arranged such that it can be twisted in relation to an inlet duct  78  connected to an inlet opening  76 , so that, through twisting of the carousel  74 , different spray nozzles  72  can be selected for application of the spray liquid. A spray nozzle body  70  of this type, which is commonly known in the prior art, can be used both in the embodiment described in relation to  FIG. 2  and in that described in relation to  FIG. 3 .