Patent Publication Number: US-2017361341-A1

Title: Rotor nozzle for a high-pressure cleaning apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of international application number PCT/EP2015/054310 filed on Mar. 2, 2015, which is incorporated herein by reference in its entirety and for all purposes. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to a rotor nozzle for a high-pressure cleaning apparatus with a housing having at least one inlet opening tangentially into the housing and an outlet which is arranged on an end wall of the housing and on which is arranged a bearing with a pan-shaped, centrally broken recess, and with a nozzle body which is arranged in the housing, has a through channel, and is supported with a spherical end in the pan-shaped recess, the longitudinal axis of which nozzle body is tilted toward the longitudinal axis of the housing and which nozzle body is brought into a revolving movement by the liquid flowing through the housing, in which revolving movement the longitudinal axis of the nozzle body revolves on a conical shell and the nozzle body is supported with a contact surface on its circumference on a support surface, wherein several flow resistance elements are arranged downstream of the support surface on the wall of the housing in the circumferential direction at a distance to one another, which flow resistance elements respectively have one baffle surface protruding into the internal space for impinging liquid. 
     By means of such a rotor nozzle, a compact liquid jet revolving on a conical shell can be produced, which liquid jet can, for example, be directed at a surface for cleaning purposes. Pressurized liquid from a high-pressure cleaning apparatus can be supplied to the inlet of the housing. In the housing is located a nozzle body which is mounted on the pan-shaped recess on only one side and which can otherwise move in the housing about the longitudinal axis of the housing. The nozzle body has a through channel, through which the liquid can pass through the broken recess of the housing. The longitudinal axis of the nozzle body is tilted with respect to the longitudinal axis of the housing. The nozzle body is pressed into the pan-shaped recess by the liquid tangentially entering the housing, which recess forms a bearing for the nozzle body, and at the same time, the nozzle body is brought into rotation about the housing longitudinal axis. This has the consequence that the exiting liquid jet also describes the desired circular movement so that the liquid can be applied to a relatively large area with a pressure comparable to spot jet nozzles. 
     Supplying the pressurized liquid via the inlet tangentially opening into the housing ensures that liquid located in the housing is brought into rotation about the longitudinal axis of the housing and that the nozzle body thereby also rotates about the housing longitudinal axis as a rotating liquid column forms inside the housing. 
     If the nozzle body has a very high rotational speed about the longitudinal axis of the housing, the consequence can be that the liquid jet exiting the outlet is fanned out and that the cleaning effect of the liquid jet impinging on an area is reduced thereby. DE 44 19 404 A1 therefore suggests to arrange several flow resistance elements disposed over the circumference on the inside wall of the housing, which flow resistance elements decelerate the flow of the liquid and thereby also reduce the rotational speed of the nozzle body. The flow resistance elements are formed by lamellas which are arranged on the upstream end of an insert that can be inserted into the housing. The insert can be moved in the longitudinal direction of the housing and has at its upstream end a plurality of slot-shaped recesses which form the lamellas between them. The lamellas respectively form a baffle surface for the flowing liquid, wherein the baffle surface opposes the liquid. 
     The rotational speed that the nozzle body has in its rotation about the housing longitudinal axis is indirectly reduced by the flow resistance elements arranged on the inside of the housing as the flow resistance elements act on the revolving liquid in a decelerating manner. It is desirable to limit the rotational speed of the nozzle body in its rotational movement about the housing longitudinal axis as effectively as possible. However, it must also be ensured that the so-called “start-up behavior” of the nozzle body is not impaired. The term “start-up behavior” refers to the starting of the rotation of the nozzle body about the housing longitudinal axis. Before pressurized liquid is supplied to the housing, the nozzle body is at rest relative to the housing, i.e., it does not yet carry out a revolving movement about the housing longitudinal axis. If pressurized liquid is now supplied via the at least one tangential inlet, the nozzle body must be brought into rotation reliably. If the nozzle body then carries out the rotational movement, the rotational speed of the nozzle body should not exceed a maximum rotational speed in order to avoid a fanning out of the liquid jet exiting the outlet. 
     The object of the present invention is therefore to further develop a rotor nozzle of the aforementioned type such that the rotational speed that the nozzle body has in its rotational movement about the housing longitudinal axis can be effectively limited without the start-up behavior of the nozzle body being noticeably impaired. 
     SUMMARY OF THE INVENTION 
     This object is accomplished according to the invention in a rotor nozzle of the generic type by a guiding surface being arranged directly upstream of each baffle surface with respect to the flow direction of the liquid, which guiding surface is continuously adjoined by the baffle surface, wherein the guiding surface is aligned obliquely to a radial plane with respect to the longitudinal axis of the housing. 
     In the rotor nozzle according to the invention, a guiding surface is arranged upstream of each baffle surface, which guiding surface is continuously adjoined by the respective baffle surface in the flow direction of the liquid. The guiding surfaces are aligned obliquely to a radial plane with respect to the longitudinal axis of the housing. The oblique alignment of the guiding surfaces has the consequence that revolving liquid is supplied along the guiding surfaces to the baffle surfaces, which oppose the revolving movement of the liquid. A significant deceleration of the liquid flow can thereby be achieved and this, in turn, has the consequence that the rotational speed that the nozzle body has in its rotational movement about the housing longitudinal axis can be limited effectively. 
     The flow resistance elements are arranged downstream of the support surface, on which the nozzle body is supported on the inside wall of the housing. In the region between the at least one inlet of the housing and the support surface, no flow resistance elements are arranged, which could impair the movement of the liquid. This ensures that the start-up behavior of the nozzle body is not noticeably impaired despite the use of the baffle surfaces and guiding surfaces. 
     It has been shown that the use of baffle surfaces and guiding surfaces cannot only limit the rotational speed that the nozzle body has in its revolving movement about the housing longitudinal axis but can also keep low the self-rotation of the nozzle body, i.e., the rotation that the nozzle body exhibits about its own longitudinal axis. Because the liquid rotating in the housing does not only have the consequence that the nozzle body rotates about the housing longitudinal axis according to the liquid. Rather, the nozzle body, in particular in its front region directly adjacent to the pan-shaped recess, is driven by the revolving liquid to a rotation about the longitudinal axis of the nozzle body. The self-rotation about the longitudinal axis of the nozzle body superposes the revolving movement of the nozzle body on the conical shell of the housing. The self-rotation has the consequence that the liquid jet flowing out of the nozzle body is also brought into rotation about its longitudinal axis. This results in an additional fanning out of the liquid jet, which fanning out impairs the cleaning effect of the liquid jet. The positioning of the baffle surfaces and guiding surfaces downstream of the support surface, on which the nozzle body is supported on the wall of the housing, results precisely in the region of the nozzle body in a deceleration of the revolving movement of the liquid jet, as a self-rotation of the nozzle body is induced by the liquid jet. The use of the baffle surfaces and guiding surfaces thus cannot only limit the rotational speed that the nozzle body has in its revolving movement about the housing longitudinal axis but can also limit the rotational speed of the self-rotation of the nozzle body. 
     As already mentioned, the baffle surfaces oppose the revolving movement of the liquid. The baffle surfaces are preferably at least in sections arranged in a radial plane with respect to the longitudinal axis of the housing. The liquid revolving about the housing longitudinal axis can thereby impinge orthogonally on the baffle surface at least in a region of the baffle surface and can thereby experience a particularly strong deceleration. 
     It is particularly advantageous if the guiding surfaces are curved in the shape of an arc at least in sections. For example, it can be provided that the guiding surfaces are curved outward convexly, i.e., in the direction facing away from the longitudinal axis of the housing, at least in sections. The arc-shaped curve results in a particularly effective change of the flow of the liquid in the direction toward the baffle surface directly following the respective guiding surface. 
     In combination with the baffle surface adjoining the guiding surface, each guiding surface advantageously forms a channel-shaped expansion of the internal space of the housing. The channel-shaped expansion extends in the direction toward the outlet of the housing. The channel-shaped expansion is preferably aligned obliquely to the longitudinal axis of the housing, in particularly parallelly to the longitudinal axis of the nozzle body. 
     It is particularly advantageous if a plurality of baffle surfaces and guiding surfaces are arranged alternatingly one behind the other with respect to the flow direction of the liquid. In the circumferential direction of the housing, the baffle surfaces and the guiding surfaces thus adjoin one another, wherein each guiding surface is followed by a baffle surface which is, in turn, adjoined by a guiding surface. 
     In an advantageous embodiment of the invention, each guiding surface forms, in combination with the baffle surface adjoining the guiding surface, an S-shaped or sawtooth-shaped contour in a plane aligned orthogonally to the longitudinal axis of the housing. It has been shown that a particularly effective deceleration of the liquid flow in a region between the support surface on which the nozzle body is supported and the outlet of the housing can be achieved thereby. 
     The guiding surface advantageously extends in the circumferential direction of the housing across a larger region than the baffle surface adjoining it. It is particularly advantageous if the guiding surface extends in the circumferential direction across a region that is at least twice as large as the baffle surface following the guiding surface. The liquid is thereby respectively supplied over a relatively large circumferential region to a baffle surface and then effectively decelerated on it. 
     It can be provided that the flow resistance elements are formed in a wall of the housing. In such an embodiment, the flow resistance elements form, together with the housing, a one-piece component. For example, it can be provided that the flow resistance elements in combination with the housing form a one-piece injection-molded part, which is preferably produced from a plastic material. 
     It can alternatively be provided that the flow resistance elements are formed by an insert that can be inserted into the housing. Such an embodiment has the advantage that the housing can be designed to be relatively thin-walled, wherein it can have on its inside a relatively smooth surface without any profile. The risk of cracks forming in the housing when highly pressurized liquid is applied to the housing can thereby be kept particularly low. The insert can form a pre-assembled component, which can be inserted into the housing. The insert thus forms an additional component that provides the flow resistance elements, without the mechanical resilience of the housing being impaired thereby. 
     It is particularly advantageous if the insert has a constant wall thickness along its circumference. This facilitates the shaping of the insert in an injection molding process. In such an embodiment, the insert has on its outside a contour that corresponds to the inside contour of the insert. 
     In an advantageous embodiment, the insert can be connected to the housing in a rotationally fixed and axially unmovable manner. Despite the deceleration effect it exerts on the revolving liquid, the insert does not carry out a rotational movement or an axial movement relative to the housing in such an embodiment. Such relative movements could result in damage to the insert and/or to the housing. The provision of a rotationally fixed and axially unmovable connection between the insert and the housing therefore allows for a longer service life of the rotor nozzle. 
     The insert can preferably be screwed to the housing and has a stop surface, which rests against an inner shoulder of the housing in the final position of the insert. The insert can in such an embodiment of the invention be screwed into the housing until it rests with its stop surface against an inner shoulder of the housing. An additional rotational movement or axial movement of the insert relative to the housing is then no longer possible. 
     Advantageously, the insert comprises an external thread, which interacts with a first internal thread of the housing. 
     The external thread of the insert is advantageously arranged downstream of the flow resistance elements. For this purpose, the housing has, upstream of the pan-shaped recess, an internal thread designed to be complementary to the external thread of the insert. 
     Advantageously the screw-in direction of the insert is identical to the revolving movement of the liquid inside the housing. The liquid revolving in the housing thus presses the insert into the final position, in which the insert rests with its stop surface against the inner shoulder of the housing. The revolving liquid thus ensures that the screw connection between the insert and the housing cannot be loosened unintentionally. 
     The internal thread of the housing is preferably designed as a multi-start thread. This has the advantage that the insert only has to be turned very little relative to the multi-start thread in order to produce a stable screw connection. For example, it can be provided that the insert must be turned relative to the housing by less than 360° in order to reach its final position. 
     As already mentioned, pressurized liquid is supplied to the inlet of the housing during the use of the rotor nozzle. The rotor nozzle can for this purpose have a connecting part that can be connected to the housing to connect to a liquid supply line. 
     The connecting part can preferably be connected to the housing in a rotationally fixed manner. 
     The connecting part advantageously has an external thread which can be screwed into a second internal thread of the housing. 
     In an advantageous embodiment, the direction of rotation of the second internal thread corresponds to the direction of rotation of the first internal thread. A corresponding direction of rotation of the two internal threads makes the shaping of the housing easier and allows for a particularly cost-effective production. 
     It can, however, also be provided that the direction of rotation of the second internal thread is opposed to the direction of rotation of the first internal thread. As mentioned, it is advantageous if the screw-in direction of the insert corresponds to the revolving movement of the liquid inside the housing. The insert is thereby pressed into its final position by the liquid. So that the reaction force of the housing does not result in a loosening of the screw connection between the housing and the connecting part, the direction of rotation of the second internal thread is advantageously opposite the direction of rotation of the first internal thread. 
     The following description of two advantageous embodiments of the invention serves the more detailed explanation in connection with the drawing. Shown are: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  a longitudinal sectional view of a first advantageous embodiment of a rotor nozzle according to the invention with a housing, in which an insert and a nozzle body are arranged; 
         FIG. 2  a longitudinal sectional view of a housing lid of the rotor nozzle of  FIG. 1 ; 
         FIG. 3  a lateral view of the insert of the rotor nozzle of  FIG. 1 ; 
         FIG. 4  a sectional view of the insert along the line  4 - 4  in  FIG. 3 ; 
         FIG. 5  a sectional view of a housing lid of a second advantageous embodiment of a rotor nozzle according to the invention, and 
         FIG. 6  a sectional view of the housing lid along the line  6 - 6  in  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1 to 4  schematically show a first advantageous embodiment of a rotor nozzle according to the invention, which rotor nozzle is overall denoted by the reference symbol  10 . The rotor nozzle  10  has a housing  12  with a housing bottom  14  and a housing lid  16 . The housing bottom  14  is designed to be disk-shaped and has several tangential inlets  18 , which open into an internal space  20  of the housing  12 . The internal space  20  is surrounded by the housing lid  16  and tapers starting from the tangential inlets  18  toward an outlet  22 , which is arranged on an end wall  24  of the housing lid  16 . 
     Via the tangential inlets  18 , pressurized liquid can be supplied to the internal space  20 , which liquid rotates about a housing longitudinal axis  26  in the internal space  20  and can exit the housing  12  via the outlet  22 . 
     Directly upstream of the outlet  22 , a bearing in the form of a bearing ring  28  is arranged in the internal space  20 , which bearing ring forms a pan-shaped recess  30 . On its outside, the bearing ring  28  carries a sealing ring  32  and is thereby sealed with respect to the housing lid  16 . 
     Upstream of the bearing ring  28 , the housing lid  16  has a first internal thread  34 , which is designed as a multi-start thread. In the exemplary embodiment shown, the first internal thread  34  is designed to be double-threaded. Upstream of the first internal thread  34 , the housing lid  16  forms an inner shoulder  36  and, upstream of the inner shoulder  36 , the housing lid  16  is designed in the shape of a conical contact region  38 . Upstream of the conical contact region  38 , the housing lid  16  forms a smooth support surface  40  without any profile, which support surface is designed to be conical in the exemplary embodiment shown. On the side facing away from the outlet  22 , the housing lid  16  has a second inner shoulder  42  at a distance to the support surface  40 , against which second inner shoulder the housing bottom  14  rests. 
     On the side facing away from the outlet  22 , the housing lid  16  forms a second internal thread  44  at a distance to the second inner shoulder  42 , the direction of rotation of which second internal thread corresponds to the first internal thread  34  in the exemplary embodiment shown. Alternatively, the direction of rotation of the second internal thread  44  can be opposed to the direction of rotation of the first internal thread  34 . 
     An insert  46  shown schematically in  FIGS. 3 and 4  is screwed into the housing lid  16 . The insert  46  has an external thread  48 , which can be screwed to the first internal thread  34  of the housing lid  16 . Upstream of the external thread  48 , the insert  46  forms a plurality of flow resistance elements  50 , which are disposed evenly in the circumferential direction and which respectively have one baffle surface  52 . A guiding surface  54  is arranged upstream of each baffle surface  52  with respect to the flow direction of the liquid. The baffle surfaces and guiding surfaces  52 ,  54  are arranged alternatingly with each other in the circumferential direction of the insert  46  and transition into each other continuously. In a plane aligned orthogonally to the housing longitudinal axis  26 , the baffle surfaces and guiding surfaces form an S-shaped contour in the exemplary embodiment shown as both the baffle surfaces  52  and the guiding surfaces  54  are curved in an arc shape. The baffle surfaces  52  have an end portion  56  aligned in a radial plane with respect to the housing longitudinal axis  26 . This can be clearly seen in  FIG. 4 . Each guiding surface  54  forms, in combination with the adjoining baffle surface  52 , a channel-shaped expansion  55 , which is aligned obliquely to the longitudinal axis  26  of the housing  12 . 
     In the circumferential direction, the insert  46  has in the region of the baffle surfaces and guiding surfaces  52 ,  54 , a constant material thickness. This facilitates the production of the insert  46  in an injection molding process. 
     The insert  46  extends from the first internal thread  34  of the housing lid  16  to an upstream edge  58  of the conical contact region  38  so that the support surface  40  is not impaired by the insert  46 . 
     In the transition region between the external thread  48  and the flow resistance elements  50 , the insert  46  forms on its outside a stop surface  60  and the insert  46  can be screwed with its external thread  48  into the first internal thread  34  until the stop surface  60  rests against the first inner shoulder  36  of the housing lid  16 . 
     After screwing the insert  46  into the housing lid  16 , a nozzle body  62  can be inserted into the internal space  20 , which nozzle body is supported with a spherical end  64  in the pan-shaped recess  30  of the bearing ring  28 . The nozzle body  62  has a nozzle  66 , which forms the spherical end  64 , and a nozzle carrier  68 , which has a through channel  72  extending in the axial direction along a longitudinal axis  70  of the nozzle body  62 . The nozzle  66  is pressed into the through channel  72 . The nozzle  66  has a nozzle channel  74  with is aligned to be flush with the through channel  72 . In its end region facing away from the nozzle  66 , the through channel  72  expands in a stepped manner. In the region of the expansion, a solid body, in the form of a steel ball  76 , amplifying the centrifugal force, is held. Adjoining the steel ball  76  in the through channel  72  in the direction of the nozzle  66  is a rectifier  78 , which has two walls standing orthogonally one above the other, extending parallelly to the longitudinal axis  70  of the nozzle body  62 , and penetrating the through channel  72  diametrically. 
     Liquid can flow around the steel ball  76  in the through channel  72  so that the liquid, after passing the rectifier  78  and the nozzle  66 , can flow through the bearing ring  28  and the outlet  22  and exit the rotor nozzle  10 . 
     At the height of the rectifier  78 , the nozzle carrier  68  has an annular groove extending in the circumferential direction, in which annular groove an O-ring  86  is held in a rotationally fixed manner. With respect to the longitudinal axis  70  of the nozzle body  62 , the O-ring  86  protrudes in the radial direction beyond the nozzle carrier  68 . Said O-ring forms a contact surface, with which the nozzle body  62  can rest against the support surface  40  of the housing lid  16 . This can be clearly seen in  FIG. 1 . 
     With respect to the longitudinal axis  70 , the nozzle body  62  extends across at least a third of its total length in the region upstream of the insert, i.e., in the region between the insert  46  and the housing bottom  14 . 
     The channel-shaped expansions  55  are aligned parallelly to the longitudinal axis  70  of the nozzle body  62 . 
     The housing  12  of the rotor nozzle  10  is screwed to a connecting part  88 , via which the housing  12  can be supplied with pressurized liquid from a high-pressure cleaning apparatus. For this purpose, the connecting part  88  has an external thread  90 , which can be screwed into the second internal thread  44  of the housing lid  16 . 
     Liquid supplied via the connecting part  88  to the housing  12  arrives through the tangential inlets  18  in the internal space  20  of the housing  12  and can exit the internal space  20  via the through channel  72 , the nozzle channel  74 , the bearing ring  28 , and the outlet  22 . During operation of the rotor nozzle  10 , the internal space  20  is filled with liquid, which is brought into rotation about the housing longitudinal axis  26  by the liquid flowing in through the tangential inlets  18 . A liquid column rotating about the housing longitudinal axis  26  thus forms in the internal space  20 . The rotating liquid column carries along the nozzle body  62  supported with its spherical front end  64  on the bearing ring  28  so that said nozzle body also rotates about the housing longitudinal axis  26 . The nozzle body  62  rests against the circular cylindrical support surface  40  via the O-ring  86  held on the nozzle body  62  in a rotationally fixed manner. The longitudinal axis  70  of the nozzle body  62  is thus tilted toward the housing longitudinal axis  26 . 
     In the region of the insert  46 , the liquid flowing around the housing longitudinal axis  26  experiences a deceleration as a result of the baffle surfaces  52 , which is struck by a portion of the revolving liquid. In the process, liquid is supplied via the guiding surfaces  54  to respectively one baffle surface  52  so that an effective deceleration of the liquid can be achieved. Upstream of the insert  46 , the liquid does however not experience any deceleration. This ensures that the nozzle body  62  is reliably brought into rotation about the housing longitudinal axis  26  by the liquid. In this region, the nozzle body  62  is only located on one side of the housing longitudinal axis  26 , whereas the nozzle body  62  crosses the housing longitudinal axis  26  in the region of the insert  46  and the nozzle  66 . This can be clearly seen in  FIG. 1 . The liquid flowing around the nozzle body  62  could drive the nozzle body  62  in the region in which it crosses the housing longitudinal axis  26  to a self-rotation about the longitudinal axis  70  of the nozzle body  62 . Since the liquid is, however, decelerated in this region by the flow resistance elements  50 , the self-rotation of the nozzle body  62  can be kept low. In addition, the provision of the flow resistance elements  50  achieves a limitation of the rotational speed that the nozzle body  62  has in its rotational movement about the housing longitudinal axis  26 . The reduction of the self-rotation of the nozzle body  62  and the reduction of the rotational speed of the nozzle body  62  about the housing longitudinal axis  26  ensure that the liquid jet exiting the housing  12  is only fanned out unnoticeably. The rotor nozzle  10  is therefore characterized by a particularly large cleaning effect. 
     The invention is not limited to the use of a pre-assembled insert  46 , which is used in addition to the housing lid  16  and the housing bottom  14 .  FIGS. 5 and 6  schematically show a housing lid  116  of a second advantageous embodiment of a rotor nozzle according to the invention. The housing lid  116  is designed to be largely identical to the housing lid  16  described above. It is distinguished from the housing lid  16  by the flow resistance elements  118  being formed directly in the housing lid  16 . The flow resistance elements  118  are designed to be identical to the flow resistance elements  50  explained above. They respectively have one baffle surface  120 , upstream of which is arranged a guiding surface  122 . The baffle surfaces and guiding surfaces  120 ,  122  transition continuously into one another and respectively form a channel-shaped expansion  123 . One baffle surface  120  and one guiding surface  122  respectively form an S-shaped contour in a plane aligned orthogonally to the housing longitudinal axis  124 . Alternatively, the baffle surfaces and guiding surfaces  120 ,  122  could also form a sawtooth-shaped contour. In the same way as the guiding surfaces  54  explained above, the guiding surfaces  122  supply liquid to the respective baffle surface  120  following in the revolving movement of the liquid, wherein the liquid is noticeably decelerated on the baffle surface  120 . 
     The housing lid  116  is used as an alternative to the housing lid  16 . The housing bottom  14  can also be inserted into the housing lid  116 , and the housing lid  116  can be screwed to the connecting part  88 . For this purpose, the housing lid  116  also has, on its end region facing away from the outlet  126 , an internal thread  128 . 
     In the same way as into the housing lid  16  explained above, the nozzle body  62  can also be inserted into the housing lid  116 , which nozzle body is driven by the liquid flowing around the housing longitudinal axis  124  to a rotation about the housing longitudinal axis  124 , wherein the rotational speed of the nozzle body  62  can be effectively limited by the provision of the flow resistance elements  118 . In addition, the use of the flow resistance elements  118  can limit the self-rotation of the nozzle body  62 , without its start-up behavior being impaired however.