CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage application filed under 35 U.S.C. § 371 of International Application No. PCT/EP2016/081869 filed Dec. 20, 2016, which application is hereby incorporated by reference herein in its entirety.

TECHNICAL FIELD

The present invention relates to a washing liquid distribution device for a dishwasher, comprising a holder and an impeller, wherein the holder is configured to hold the impeller within a washing chamber of a dishwasher. The present invention further relates to dishwasher comprising a washing liquid distribution device.

BACKGROUND

A dishwasher is an apparatus for washing items by using a force of washing liquid directed onto the items by one or more washing liquid distribution devices. There are many requirements of today's dishwashers. Examples of such requirements are that a dishwasher is expected to wash items with a good cleaning result while environmental concerns require an efficient use of energy and washing liquid during a washing session. In addition, it is an advantage if the dishwasher is designed such that the sound emitted from the dishwasher is low during a washing session. Further, on the consumer market, it is an advantage if high quality products can be provided in a cost-efficient manner. In order to achieve a proper washing result, one important aspect is washing liquid distribution capability of washing liquid distribution devices of the dishwasher. In order to keep the sound level low during the wash session, it is an advantage if pressure of washing liquid from washing liquid distribution devices can be kept low. However, a too low pressure may result in a poor washing result. Accordingly, many of the requirements of today's dishwasher can be seen as conflicting requirements.

Traditionally, a dishwasher comprises a set of elongated wash arms rotatably arranged a washing chamber of the dishwasher. However, in order to meet some of the above-mentioned requirements, washing liquid distribution devices comprising impellers have been developed. Examples of washing liquid distribution devices comprising impellers are described in the document EP 1232720 A2 and the document US 2010116301 A1. Washing liquid distribution devices comprising impellers have several advantages over traditional wash arms. One such advantage is that the risk of stop of rotation is significantly reduced as compared to a traditional wash arm. Another advantage is that washing liquid distribution devices comprising impellers require less space than traditional wash arms. Therefore, such washing liquid distribution devices can be arranged vertically in the washing chamber and at positions in the washing chamber in which a traditional washing arm could not be fitted, or would be unsuitable.

However, in view of the prior art washing liquid distribution devices comprising impellers, there is room for improvement, especially regarding washing liquid distribution capability of the washing liquid distribution devices.

SUMMARY

It is an object of the present invention to provide a washing liquid distribution device with improved washing liquid distribution capability.

According to an aspect of the invention, the object is achieved by a washing liquid distribution device for a dishwasher, wherein the washing liquid distribution device comprises a holder and an impeller, wherein the holder is configured to hold the impeller within a washing chamber of a dishwasher. The impeller comprises a disc-shaped body provided with a plurality of impeller blades extending from a surface of the disc-shaped body. The impeller blades comprise driving blades being angled in a first direction in relation to a radial direction of the disc-shaped body of the impeller to cause rotation of the impeller when washing liquid is directed onto the driving blades. The impeller blades further comprise at least one backflow blade being angled in a second direction in relation to the radial direction of the disc-shaped body, where the second direction is opposite to the first direction.

Since the impeller blades comprise at least one backflow blade being angled in the second direction, washing liquid will be distributed differently from the backflow blade than from the driving blades being angled in a first direction with regard to distribution angle and distribution velocity from the impeller. Thereby, a more varying distribution pattern from the washing liquid distribution device is provided. As a result, washing liquid distribution capability is improved. Dishware arranged in a dishwasher comprising the washing liquid distribution device will be subjected to washing liquid from different angles and with different velocities, thus improving washing intensity, while a flowrate of washing liquid to the washing liquid distribution device can be kept low.

Further, due to these features, rotational velocity of the impeller may vary during one revolution of the impeller since the backflow blade is angled in the second direction being opposite to the first direction of the driving blades. As a result thereof, washing liquid distribution capability is further improved since washing liquid will be distributed differently from the impeller blades during rotation of the impeller with regard to distribution angle and distribution velocity from the impeller blades.

Accordingly, a washing liquid distribution device is provided with improved washing liquid distribution capability. As a result, the above mentioned object is achieved.

Further, since the washing liquid distribution capability is improved, a washing liquid distribution device is provided which more efficiently utilizes flow of washing liquid thereby providing conditions for a reduced consumption of energy and washing liquid for a dishwasher provided with the washing liquid distribution device.

Optionally, the impeller blades comprise at least one combined blade having a first portion being angled in the first direction and a second portion being angled in the second direction. Thereby, a jet of washing liquid, or a portion of a washing liquid flow, directed towards the combined blade may during rotation of the impeller first hit the second portion being angled in the second direction, to distribute washing liquid differently than when hitting other impeller blades, and then hit the first portion being angled in the first direction to contribute to rotation of the impeller. As a result, a washing liquid distribution device is provided with even further improved washing liquid distribution capability.

Optionally, the impeller blades comprise a first, a second and a third driving blade each having different average angles in relation to the radial direction of the disc-shaped body. Since the first, the second and the third blade driving blade each has different average angles in relation to the radial direction of the disc-shaped body, the respective driving blade will distribute washing liquid differently than the other driving blades regarding distribution angle and distribution velocity from the driving blades. Still, the first, the second and the third blade driving blade will contribute to rotation of the impeller, since they are angled in the first direction in relation to the radial direction of the disc-shaped body. As a result, a washing liquid distribution device is provided with even further improved washing liquid distribution capability. In addition, the different average angles in relation to the radial direction of the disc-shaped body of the first, the second and the third blade driving blade may contribute to a varying rotational velocity of the impeller which further may improve washing liquid distribution capability.

Optionally, the first driving blade is arranged prior to the second driving blade seen in an intended direction of rotation of the impeller, and wherein the first driving blade is provided with a greater average angle in relation to the radial direction r of the disc-shaped body than the second driving blade. As a result, the impeller will be subjected to a progress of acceleration when the first and second driving blades passes a jet of washing liquid, or a portion of a washing liquid flow. Thereby, a more varying velocity of the impeller is provided and distribution of washing liquid is further improved.

Optionally, the third driving blade is arranged after the second driving blade, seen in an intended direction of rotation of the impeller, and wherein the third driving blade is provided with a smaller average angle in relation to the radial direction of the disc-shaped body than the second driving blade. As a result, the impeller will be subjected to a progress of acceleration when the second and third driving blades passes a jet of washing liquid, or a portion of a washing liquid flow. Thereby, a more varying velocity of the impeller is provided and distribution of washing liquid is further improved.

Optionally, the impeller blades further comprise at least one rebound blade comprising a parabolic or cup-shaped portion essentially facing a centre of the impeller. Thereby, washing liquid hitting the parabolic or cup-shaped portion of the rebound blade may rebound towards the centre of the of the impeller, and/or may rebound a direction away from the surface, of the disc-shaped body from which the impeller blades extend. Further, the washing liquid may rebound through a through hole of the impeller to a side of the impeller opposite to the surface of the disc-shaped body from which the impeller blades extend. Thereby, the washing liquid distribution capability can be further improved. In addition, washing liquid being rebound towards the centre of the of the impeller may strike against washing liquid being directed in a direction towards the impeller blades. Thereby, an even more varying distribution pattern from the washing liquid distribution device can be provided which further improves washing liquid distribution capability.

Optionally, the impeller blades comprise at least one bi-convex blade having a bi-convex shape. A bi-convex shape is advantageous for directing washing liquid due to flow guiding characteristics of the bi-convex shape. The least one blade having a bi-convex shape may therefore direct washing liquid further into a washing chamber of the dishwasher than the other impeller blades and may distribute washing liquid differently regarding distribution velocity and distribution angle than the other impeller blades. Thereby, a more varying distribution pattern from the washing liquid distribution device is provided and the washing liquid distribution capability is further improved.

Optionally, the surface of the disc-shaped body, from which the plurality of impeller blades extend, is curve-shaped. Thereby, washing liquid directed onto the driving blades will be guided along the surface of the disc-shaped body, from which the plurality of impeller blades extend, and due to the curve shape be deflected. As a result, a washing liquid distribution device is provided with even further improved washing liquid distribution capability.

Optionally, the surface is convex. Thereby, washing liquid directed onto the driving blades will be guided along the convex surface of the disc-shaped body, from which the plurality of impeller blades extend, and as a result thereof be deflected into an area of a washing chamber being opposite to the surface of the disc-shaped body. As a result, a washing liquid distribution device is provided with even further improved washing liquid distribution capability.

Optionally, the impeller blades extend from the surface of the disc-shaped body between an inner radius and an outer radius of the disc-shaped body, wherein the holder is arranged to direct washing liquid onto the impeller blades at the inner radius. Thereby, an efficient distribution of washing liquid to the impeller blades is provided. Further, a compact washing liquid distribution device is provided.

Optionally, the holder comprises nozzles arranged to direct washing liquid onto the impeller blades. Thereby, a controlled and efficient distribution of washing liquid to the impeller blades is provided, which may require less flowrate of washing liquid to rotate the impeller since nozzles may provide a higher velocity of washing liquid than a solution without nozzles.

Optionally, the nozzles are arranged to direct washing liquid onto the impeller blades in directions having an angle in relation to radial directions of the disc-shaped body. Thereby, a washing liquid distribution device is provided with even further improved washing liquid distribution capability since washing liquid is hitting the impeller blades in directions having an angle in relation to radial directions of the disc-shaped body.

Optionally, the angle is a positive angle in relation to an intended direction of rotation of the impeller. Thereby, washing liquid will hit the respective impeller blade in an angle contributing to the rotation of the impeller. Thereby, rotational velocity of the impeller will increase while providing conditions for a reduced flowrate of wash liquid. Due to the increased rotational velocity of the impeller, a washing liquid distribution device is provided with even further improved washing liquid distribution capability. In addition, a washing liquid distribution device is provided more efficiently utilizing flow of washing liquid thereby providing conditions for a reduced consumption of energy and washing liquid.

It is a further object of the present invention to provide a dishwasher with improved washing liquid distribution inside a washing chamber of the dishwasher.

According to a further aspect of the invention, the further object is achieved by a dishwasher comprising a washing chamber and a washing liquid distribution device according to some embodiments, wherein the washing liquid distribution device is arranged to distribute washing liquid inside the washing chamber of the dishwasher. Since dishwasher comprises a washing liquid distribution device with improved washing liquid distribution capability being arranged to distribute washing liquid inside the washing chamber of the dishwasher, a dishwasher is provided with improved washing liquid distribution inside the washing chamber of the dishwasher.

As a result, the above mentioned further object is achieved.

Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following detailed description.

