• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Water jet propulsion for a water craft, wherein a water jet can be drawn in through a hull opening (3) and ejected through at least one nozzle opening, the hull opening (3) being provided with a protective grating (1) formed of at least one primary grid bar (10 ) and the at least one primary grid bar (10) intersecting secondary grid bars (11) and wherein the at least one primary grid bar (10) is oriented along the longitudinal centerline (L) of the watercraft when sailing straight ahead of the watercraft, the secondary grid bars ( ll) are of circular arc design, whereby when sailing straight ahead the radius of the successive secondary grate bars (ll), starting from the most forward arranged secondary grate bar (ll), is designed in ascending order and the imaginary centers of the secondary grating bars (ll) on a common , along the longitudinal axis preceding the secondary grid bars (ll) are positioned.
    公开号:NL2024913A
    申请号:NL2024913
    申请日:2020-02-14
    公开日:2020-09-18
    发明作者:Mac Nelly Steven；Benke Dietrich；Mertes Paul
    申请人:Schottel Gmbh；
    IPC主号:
    专利说明:

    Description: The invention relates to a water jet propulsion for a watercraft, wherein a water jet can be drawn in through a hull opening and ejected through at least one nozzle opening, the hull opening being provided with a protective grating formed of at least one primary grid bar and the at least one primary grid bar intersecting secondary grid bars and wherein the at least one primary grid bar is oriented along the longitudinal centerline of the water vessel when sailing the watercraft straight ahead.
    Water jet drives, for example pump jets, are known with such protective grids. Protective grilles on water jet drives have the function of protecting the following impeller or impeller, respectively, against collisions with solid objects, such as floating wood or stones. With known protective grids, the supply of water is not diverted in a targeted manner. The feed breaks off at the top of the lead-in funnel at high cruising speeds and leads to areas of dislodgement. The grid bars attached in the feed diversion area reinforce this behavior. This locally leads to cavitation that continues until the entry of the idler wheel.
    GB932633A is concerned with a waterjet drive where the feed enters the waterjet drive through blade-shaped nozzles. Such designed suction nozzles entail the risk of foreign bodies getting stuck in the interior of the nozzle, which impairs the operation of the water jet propulsion and which are difficult to remove again.
    Also in GB1087798A a water jet drive is disclosed.
    A grid is arranged at the inlet, by the embodiment of which the profile of the flow is adapted, preventing disturbing objects from entering.
    It is therefore an object of the invention to propose a device of the above-mentioned type by means of which the bypass of the flow can be influenced in order to increase the thrust due to the improved flow and a decreased flow resistance, while at the same time preventing cavitation which damages the water jet propulsion.
    To achieve this object, according to the invention, a device is proposed according to the features of claim 1. Advantageous embodiments and further developments of the invention are the subject of the dependent claims.
    According to the invention, a water jet propulsion system is designed for a water craft, in which the secondary grid bars are designed in the form of a circular arc.
    When sailing straight ahead, the radius of the successive secondary grid bars starting from the pre-mounted secondary grid bar is made up in steps and the imaginary centers of the secondary grid bars are positioned on a common axis extending along the longitudinal axis in front of the secondary grid bars. .
    The distance between the arcuate secondary grid bars is constant on the axis extending along the longitudinal axis L.
    This embodiment has the advantage that disconnection of the current at the protective grid is prevented.
    Furthermore, with this embodiment, cavitation at the protective grille that is transferred to the impeller can be prevented.
    At the same time, the thrust of the waterjet propulsion at high ship speeds is increased by the improved supply and the reduced flow resistance.
    According to a proposal of the invention, the radius of the secondary grid bars increases in a mathematical order with the equation Di = p * Dnw-1y + pP * Dir-zy, where n is a natural number greater than or equal to 1. An example of this relationship is the Fibonacci sequence.
    This arrangement supports the optimal redirection of the supplied water flow for the impeller within the water jet drive.
    According to an exemplary embodiment of the invention, each primary and / or each secondary grid bar is designed in the shape of a drop in cross-section. In accordance with a further proposal of the invention, each primary and / or secondary grid bar includes a blunt side of the break. This version in the form of a drop with a blunt side of the break-off ensures the lowest possible flow resistance. Due to the blunt side of the break-off, the supply takes place with as few eddies as possible. In this way, on the one hand, the interior of the water jet drive can be protected against foreign bodies, on the other hand, the protective grid is as little disturbing as possible to the operation of the water jet drive with the use of high approach speeds with as few eddies as possible. A next possible embodiment provides that one or more of the primary and / or one or more of the secondary grid bars are in the form of a droplet and with a blunt end of the break.
    According to a further proposal of the invention, the hull opening comprises an inlet funnel and an approach plate. The approach plate is disposed at the most forward, i.e. when the watercraft travels straight towards the bow, the nearest arranged secondary grate rod in front thereof. The water flow can be sent to the inlet funnel via the flow plate. The flow plate causes the flow to be evenly fed into the inlet funnel without loosening and causing cavitation. This has the advantage that the allocated
    water flow for the impeller within the water jet drive is optimally diverted. Furthermore, due to the combination of the flow plate and the circular arc-shaped secondary grid bars, no areas of cavitation occur on the protective grid which can then be transferred to the impeller. The improved run-in to the impeller and the reduced flow resistance at the protective grille lead to a higher specific pressure of the water jet drive and at the same time enable a higher final speed.
    According to a further exemplary embodiment of the invention, in the region in which the flow plate is adjacent to the inlet funnel, a zone is provided without grid bars. The highest flow velocity prevails in this area and the formation of a zone without grids prevents eddies and breakdown of the flow. This version additionally ensures an even flow to the impeller.
    According to a further proposal of the invention, the secondary grid bar with the smallest radius ends at a transition between the flow plate and the inlet funnel. From this secondary grid bar, the radius increases to each subsequent secondary grid bar in steps. This design keeps the current resistance in this area as small as possible.
    According to an exemplary embodiment of the invention, the approach plate is connected to the inlet funnel and the protective grid. This design prevents increased flow resistances from occurring at the transition from the approach plate to the inlet funnel as a result of inaccurate fitting. Another possibility consists of designing the approach plate as a separate construction part. This allows it to be retrofitted to existing installations.
    The invention is then illustrated in more detail with reference to the drawing. Here: Figure 1 shows a top view of the protective grid with an approach plate,
    figure 2 shows a perspective view of the protective grid shown in figure 1, figure 3 a top view of a protective grid according to the prior art, figure 4 a cross-sectional view of the protective grid shown in figures 1 and 2.
    Figure 1 shows an exemplary embodiment of a water jet propulsion with a protective grid 1 composed of primary 10 and secondary grid bars 11. The watercraft is in a straight line of travel and the waterjet propulsion is directed along the longitudinal centerline L of the watercraft. The radius of each secondary grid bar 11 increases in steps, with the imaginary centers of the secondary grid bars 11 positioned on a common axis running along the longitudinal centerline L in front of the secondary grid bars
    11. The distance of the circular arc-shaped secondary grid bars 11 is constant on the axis running along the longitudinal axis L. The securing of the secondary grid bar 11 with the smallest radius takes place laterally at the transition between an approach plate 4 and an inlet funnel 2. This ensures that the zone with the strongest bypass 5 of the flow and therefore a maximum flow velocity is located at the inlet funnel 2. there are no grid bars. The approach plate directs the flow through the inlet funnel 2 into the hull opening 3 and into the interior of the water jet drive.
    Figure 2 shows the exemplary embodiment of figure 1 in a perspective view. The water flows in a direction of the main flow via the approach plate 4 into the inlet funnel 2 which opens into the hull opening 3. In the zone of the strongest bypass 5 of the flow, the supplied flow is guided unobstructed into the hull opening 3 as there are no grid bars here applied to initiate a breakdown of the current.
    Figure 3 shows a protective grid 1 according to the prior art. The primary grid bars 10 run parallel to each other and the secondary grid bars 11 are also parallel to each other and are arranged at right angles to the primary grid bars 10. The distances between the parallel grid bars are always the same. The grid bars are arranged circumferentially on the inlet funnel 2. In the zone of the strongest diversion 5 of the flow are grid bars. In the zone of the strongest bypass of the current, the grid bars present there cause the current to break off. The current is suddenly diverted and cannot follow the contour of the run-in sufficiently. This causes cavitation. Over time, the cavitation will damage structural components of the waterjet propulsion system, such as the impeller. Furthermore, the flow resistance in this exemplary embodiment is increased relative to the subject matter of the application, which has negative consequences for the thrust power of the water jet propulsion. The diamond-shaped arrangement of the grid bars interferes with the flow in the zone of the maximum bypass of the flow, which further aggravates the occurrence of cavitation.
    Figure 4 shows a cross-sectional view of the exemplary embodiment already shown in Figures 1 and 2. Due to the design of the flow plate 4, the supplied water flow is optimally diverted for the impeller within the water jet drive. The secondary grid bars 11 are drop-shaped and have a blunt side 12 of the break-off in order to keep the flow resistance as small as possible and at the same time keep unwanted objects away from the hull opening 3.
    REFERENCE NUMBER 1 Primary grid bar guard 11 secondary grid bar 12 blunt side of breakdown 2 inlet hopper 10 3 hull opening end 4 approach plate 5 zone of strongest flow diversion 6 direction of main flow L longitudinal centerline of watercraft
    权利要求:
    Claims (8)
    [1]
    1. Water jet propulsion for a water craft, wherein a water jet can be sucked in through a hull opening (3) and ejected through at least one nozzle opening, the hull opening (3) being provided with a protective grating (1) formed of at least one nozzle opening. maire grid bar (10) and the at least one primary grid bar (10) intersecting secondary grid bars (11) and wherein the at least one primary grid bar (10) is oriented along the longitudinal centerline (L) of the watercraft when sailing straight ahead of the watercraft , characterized in that the secondary grate bars (11) are of circular arc design, whereby during straight sailing the radius of the successive secondary grate bars (11) is made ascending stepwise from the most forward arranged secondary grate bar (11) and the imaginary centers of the secondary grid bars (11) on a common axis extending along the longitudinal axis preceding a of the secondary grid bars (11) are positioned.
    [2]
    Water jet propulsion system according to Claim 1, characterized in that the jet rises in a mathematical sequence of the designation D = p * D (1-1) + pP * Dm-2.
    [3]
    Water jet propulsion system according to Claim 1 or 2, characterized in that each primary (10) and / or secondary grid rod (11) is of drop-shaped cross-section.
    [4]
    Water jet propulsion system according to any one of claims 1 to 3, characterized in that each primary (10) and / or secondary grid bar (11) has a blunt side (12) of the break-off.
    [5]
    Water jet drive for any one of claims 1 to 4, characterized in that the hull opening has an inlet funnel
    (2) comprises and is arranged in front of the frontmost arranged secondary grid bar (11) an inflow plate (4) over which the water flow can be guided to the inlet funnel (2).
    [6]
    6. Water jet propulsion system according to claim 5, characterized in that in the area in which the approach plate adjoins the inlet funnel, a zone is provided without grid bars.
    [7]
    Water jet propulsion system according to Claim 5 or 6, characterized in that the secondary grid rod (11) with the smallest jet ends at a transition between the flow plate (4) and the inlet funnel (2).
    [8]
    Water jet propulsion system according to any one of claims 5 to 7, characterized in that the approach plate (4) is connected to the intake funnel (2) and the protective grid (1).
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    同族专利:
    公开号 | 公开日
    DE102019106717A1|2020-09-17|
    NL2024913B1|2021-10-04|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    DE102019106717.0A|DE102019106717A1|2019-03-15|2019-03-15|Water jet propulsion for a watercraft|
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