The present invention relates to a dishwasher having a washing chamber in which is rotatably mounted at least one spray arm.
European Patent Application EP 1 040 786 A1 describes a dishwasher having pulsed nozzles, in which one arm has a plurality of nozzles which are supplied with each other with wash water via different channels. One channel is in communication with what is referred to as auxiliary nozzles. The supply of wash water to said auxiliary nozzles can be shut off by a valve. This enables the wash water to exit in pulses, partially preventing wash water from being sprayed out of the auxiliary nozzles.
German Patent Application DE 10 2004 018 878 A1 describes a dishwasher having a spray arm in which individual spray nozzles can be activated and deactivated without using additional actuators. This enables the spraying of the dishes to be pulsed according to the variation of the pump pressure to allow for effective cleaning. To this end, elastic means are provided which are capable of opening and closing the individual nozzles. However, the known nozzles have the problem that the spray jet always exits in a manner that corresponds to the nozzle opening. No provision is made to change the geometry of the spray jets and, therefore, the spray jets cannot effectively reach problem areas, for example in pots, corner areas of the washing chamber, or other areas that are difficult to access. This is because, although pulsed operation is possible, the exiting spray jet still has a given geometry.
The dishwasher proposed in DE 10 2005 026 558 B3 uses at least one spray arm within which a rotating element creates pulsed spray jets.
European Patent Application EP 1 334 687 A1 describes a spray arm having spray nozzles whose spraying characteristics can be changed by plate-shaped actuation elements. To this end, a manual operation is required of the user.
In an embodiment, the present invention provides a dishwasher including a washing chamber and at least one spray arm rotatably mounted in the washing chamber. The at least one spray arm includes a plurality of nozzles. Each nozzle is configured for spraying wash water in a respective spray jet. The plurality of nozzles are supplied with wash water by a pump. A flow obstacle is disposed in the spray arm upstream of a first nozzle of the plurality of nozzles and configured to change a geometry of the respective spray jet.
An exemplary embodiment of the present invention is shown in the drawings in a schematic way and will be described in more detail below. In the drawings:
An embodiment of the present invention provides a dishwasher in which, the spray arms have a simple design. The jets of wash water sprayed from the spray arms can be at least partially adjusted.
In accordance with the present invention, a flow obstacle is provided within the spray arm upstream of at least one nozzle to change the geometry of the spray jet. It has been found that the geometry of the exiting spray jet can be changed by a flow obstacle that is disposed within the spray arm proximate to the nozzle, so that the spray jet can not only issue from the spray arm in a straight line, but may also have other geometries, increasing the cleaning performance. It is especially by changing the geometry of the spray jet that hard-to-access areas, such as in pots or in corners, can be reached effectively.
In a preferred embodiment of the present invention, the spray arm takes the form of a hollow member, and a flow obstacle is held to the inner wall of the hollow member opposite the nozzle. As a result, defined flow channels are created within the spray arm, so that the exiting fluid forms a spray jet that corresponds to the configuration of the flow obstacle and the nozzle. In order to minimize the influence of pressure fluctuations, the flow obstacle may extend into close proximity to the exit area of the spray jet at the nozzle, for example to a distance of less than about 4 mm therefrom.
In accordance with another embodiment of the present invention, the flow obstacle is movable relative to the nozzle located in the vicinity thereof. This allows the shape of the spray jet to be adjusted, it being possible for the adjustment to be made either manually prior to the washing process or automatically, for example, depending on the pressure.
Preferably, the spray arm is provided with a plurality of distributed nozzles which are each associated with a flow obstacle. This allows a suitable flow obstacle to be associated with a nozzle depending on the location of the nozzle. For example, in an outer region, it is advantageous to provide flow obstacles that create a slightly wider spray jet, while nozzles disposed in the radially inner region of the spray arm may rather produce a narrower, stronger jet.
The flow obstacle may preferably be in the form of a peg having a rounded surface, so that a conical spray jet will be produced. It is also possible for the flow obstacle to take the form of a V-shaped ramp, a helix, or a pin, so as to produce a particular spray jet.
A spray arm 1 is disposed in a washing chamber of a dishwasher. The spray arm takes the form of a hollow member 2 and is provided at a central opening with a coupling portion 3 for connection to a conduit system of the dishwasher. Thus, wash water can be pumped into spray arm 1 by a pump. Coupling portion 3 is located at a central axis of rotation A of spray arm 1.
A first wall 4 of hollow member 2 has formed therein a plurality of nozzles 5 via which the wash water can be sprayed onto items to be washed. Further, one or more driving nozzles 6 may be provided to allow spray arm 1 to rotate during the washing operation. Nozzles 5 may point upward, as shown in the figures. Alternatively, they may be directed downwardly to provide for the cleaning of items located under the spray arm.
Within hollow member 2, flow obstacles 8 are provided upstream of at least some of nozzles 5, said flow obstacles extending from opposite wall 7 of hollow member 2 toward nozzles 5. Each flow obstacle 8 is associated with one nozzle 5.
The function of the flow obstacle is described with reference to
In
In
In the embodiments of
In the exemplary embodiment shown in
In
The flow obstacles shown in
Pegs 8″ having a rounded surface are provided as flow obstacles proximate to nozzles 5. However, these pegs are not fixedly attached to wall 7 of hollow member 2 opposite nozzles 5, but can be moved by a spring member 9″. Because of this, the distance of flow obstacle 8″ from nozzle 5 is dependent on the pressure within spray arm 1, so that at a higher pump speed, flow obstacles 8″ are pushed further away from nozzle 5 than at a lower pump speed. Thus, the spray jet from nozzles 5 is varied depending on the pressure within spray arm 1.
According to
When flow obstacles 8″ or 8″' are resiliently mounted, the geometry of the flow obstacles can also be selected relatively freely. In particular, the flow obstacles shown in
In the exemplary embodiments shown, flow obstacles 8 or either fixedly, adjustably or resiliently supported on bottom 7. Of course, it is also possible to provide a spray arm with different flow obstacles 8, some of which are fixedly supported, some of which are adjustably supported, and some of which are resiliently supported. In addition, the flow obstacles within one spray arm may have different geometries, which allows spray jets having different geometries to be produced at the individual nozzles 5. In this connection, nozzle 5 may be provided with a slit opening, or with an opening having a different geometry, in place of a circular exit area.
While the invention has been described with reference to particular embodiments thereof, it will be understood by those having ordinary skill the art that various changes may be made therein without departing from the scope and spirit of the invention. Further, the present invention is not limited to the embodiments described herein; reference should be had to the appended claims.
Number | Date | Country | Kind |
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10 2007 038 469.8 | Aug 2007 | DE | national |
This application is a U.S. National Phase application under 35 U.S.C. §371 of International Application No. PCT/EP2008/006260, filed on Jul. 30, 2008 and claims benefit to German Patent Application No. DE 10 2007 038 469.8, filed on Aug. 14, 2007. The International Application was published in German on Feb. 19, 2009 as WO 2009/021626 A1 under PCT Article 21(2).
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP08/06260 | 7/30/2008 | WO | 00 | 2/11/2010 |