Patent Publication Number: US-11026555-B2

Title: Dishwasher comprising a wash arm arrangement

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a national stage application filed under 35 U.S.C. § 371 of International Application No. PCT/EP2015/080746 filed Dec. 21, 2015, which application is hereby incorporated by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to a dishwasher comprising a wash arm arrangement. 
     BACKGROUND 
     Today&#39;s dishwashers are expected to perform high quality wash of dishware, and environmental concerns require an efficient use of energy and water during operation. A dishwasher usually comprises a washing chamber in which an upper rack and a lower rack for accommodating items to be washed are arranged. In some modern dishwashers it is possible to adjust the upper rack in height to adapt the rack to different sizes of dishes. Further, a dishwasher usually comprises an upper wash arm and a lower wash arm. The upper wash arm may be attached to the upper rack or to an interior wall of the washing chamber and the lower arm may be arranged above a sink at a bottom part of the washing chamber. 
     One problem is to configure a dishwasher with a wash arm capable of thoroughly rinsing any dishware arranged at a rack and also all necessary parts and locations within the washing chamber. Another problem is to achieve a less complex dishwasher with maintained or increased functionality. A further problem is to configure a wash arm to perform proper washing of the dishes and to enable a proper rinse at all the desired locations in the dishwasher independently of rack and/or wash arm position. 
     SUMMARY 
     An object of embodiments herein is to provide a dishwasher capable of efficient rinsing of all necessary parts and locations within the washing chamber. 
     According to an aspect of the invention, the object is achieved by a dishwasher having a washing chamber and a door comprising a detergent dispenser, the dishwasher comprising a wash arm arrangement with a rotatable first wash arm arranged within the washing chamber, wherein the wash arm arrangement comprises a second wash arm which is rotatably attached to the rotatable first wash arm, the second wash arm comprising a spray nozzle arranged to expel washing liquid in a direction relatively the second wash arm, wherein the second wash arm is arranged to bring the spray nozzle along a circular path with a radius in a plane during a rotation cycle of the second wash arm, wherein the direction has a first angle in the plane relatively the radius and a second angle relatively the plane, and wherein the spray nozzle is arranged to be directed in the direction towards the detergent dispenser during at least a portion of the rotation cycle to cause the washing liquid to intersect with the detergent dispenser. 
     Since the wash arm arrangement comprises the second wash arm which is rotatably attached to the rotatable first wash arm the entire second wash arm will be rotated via the rotatable first wash arm during operation of the dishwasher. The rotatable first wash arm can also be referred to as first wash arm. The spray nozzle of the second wash arm will also cause the second wash arm to rotate around a centre axis of the second wash arm. Hereby expelled washing liquid will be efficiently distributed over any dishware arranged on racks within the washing chamber. 
     Since the spray nozzle is arranged to be directed in the direction towards the detergent dispenser during at least a portion of the rotation cycle to cause the washing liquid to intersect with the detergent dispenser it can also be referred to as detergent dispenser nozzle. A beam of washing liquid expelled through the spray nozzle will directly hit the detergent dispenser during at least a portion of the rotation cycle. 
     The spray nozzle is directed with the first angle relatively the radius and the second angle relatively the plane. The first angle and the second angle are selected such that the washing liquid expelled through the spray nozzle intersects with the detergent dispenser during at least a portion of the rotation cycle. In other words, a beam of washing liquid expelled through the spray nozzle will directly hit the detergent dispenser during at least a portion of the rotation cycle. Hereby the detergent dispenser will be rinsed more efficiently than if only rinsed by any washing liquid scattered within the washing chamber as a function of rotating wash arms. It is hereby ensured that no residual washing powder or liquid detergent is left in the detergent dispenser. Accordingly, efficient rinsing within the detergent dispenser is achieved by a sole spray nozzle. As a result, the above mentioned object is achieved. 
     Optionally, the second angle is in the range of 1-60 degrees. Thereby, the washing liquid will be expelled by the spray nozzle towards the detergent dispenser at the second angle in the range of 1-60 degrees. Since the washing liquid will be expelled at the second angle in the range of 1-60 degrees the distance for the washing liquid to travel from the nozzle to the door of the dishwasher will be greater as compared to a distance between the spray nozzle and the door if the second angle is 0 degree and if the washing liquid is expelled by the spray nozzle in the rotation plane of the spray nozzle. Hereby an intersection path between the door and a beam of washing liquid on a surface of the door which faces the washing chamber will have a relatively long vertical extension. With a relatively long vertical extension of the intersection path the washing liquid can be controlled to intersect with, or hit, the detergent dispenser independently of a relative height between the second wash arm and the detergent dispenser. The length of the vertical extension of the intersection path depends e.g. on the second angle. A larger second angle provides for a longer vertical extension of the intersection path. The length of the vertical extension may alternatively be referred to as a height or magnitude of the vertical extension. 
     Optionally, the second angle is directed downwards relatively the plane. Thereby, the detergent dispenser can be efficiently rinsed when arranged lower than the plane. 
     Optionally, the second angle is directed upwards relatively the plane. Thereby, the detergent dispenser can be efficiently rinsed when arranged at a position above the plane. 
     Thus, the second wash arm can be arranged to efficiently rinse detergent dispensers independently of a relative height between the second wash arm and the detergent dispenser. 
     Optionally, the first angle is in the range of 45-89 degrees. Thereby, the washing liquid will be expelled by the spray nozzle towards the detergent dispenser at the first angle in the range of 45-89 degrees. In some embodiments the first angle is sharp. Thus, the washing liquid will be expelled by the spray nozzle in a direction inwards relatively the circular path. Since the washing liquid will be expelled inwards relatively the circular path the spray nozzle may be arranged such that the second angle will be relatively small. Thereby the washing liquid expelled towards the detergent dispenser will hit the detergent dispenser with a less acute angle relatively a main extension of the detergent dispenser. Thus, an efficient rinsing of the detergent dispenser is achieved. Since the washing liquid will be expelled inwards relatively the circular path also an even rinse of dishes arranged within the washing chamber will be achieved. 
     Optionally, the first angle is in the range of 91-135 degrees. Thereby, the washing liquid will be expelled by the spray nozzle towards the detergent dispenser at the first angle in the range of 91-135 degrees. Thus, the washing liquid will be expelled by the spray nozzle in a direction outwards relatively the circular path. Since the washing liquid will be expelled by the spray nozzle in the direction outwards the circular path, the spray nozzle can be arranged such that the second angle will be relatively large. Thereby, the washing liquid will also be effectively expelled towards dishes arranged within the washing chamber during portions of some of the rotation cycles. Thus, more effective washing of dishes arranged within the washing chamber is achieved. 
     Optionally, the wash arm arrangement is an upper wash arm arrangement, arranged to be mounted above any lower wash arm arrangement within the washing chamber. Hereby the wash arm arrangement can be positioned such that the washing liquid from the spray nozzle efficiently can reach the detergent dispenser when the detergent dispenser is positioned at a middle- or upper portion of the door. 
     Optionally, the wash arm arrangement is arranged to be displaceable between a first position and a second position, the first position and the second position being different height positions within the washing chamber. A sole spray nozzle according to embodiments herein is capable to efficiently rinse the detergent dispenser independently of whether the wash arm arrangement is positioned within the first or second position, i.e. independently of the relative height between the second wash arm and the detergent dispenser. 
     Optionally, the rotatable first wash arm is arranged to rotate at a first velocity and the second wash arm is arranged to rotate at a second velocity, the first velocity being different from the second velocity. Hereby the first wash arm and the second wash arm will have different mutual positions for different rotational cycles of the second wash arm whereby even and efficient rinsing of the dishwasher is achieved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The various aspects of the invention, including its particular features and advantages, will be readily understood from the following detailed description and the accompanying drawings, in which; 
         FIG. 1  illustrates a dishwasher and a wash arm arrangement according to some embodiments, 
         FIG. 2  illustrates a wash arm arrangement according to some other embodiments, 
         FIG. 3  illustrates a wash arm arrangement according to some alternative embodiments as seen from above, 
         FIG. 4  illustrates a wash arm arrangement according to yet some alternative embodiments as seen from above, and 
         FIG. 5  illustrates a door of the  FIG. 1  dishwasher according to some embodiments and paths from washing liquid beams sprayed on the door. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments herein will now be described more fully with reference to the accompanying drawings. Like numbers refer to like elements throughout. 
       FIG. 1  illustrates a dishwasher  1  having a washing chamber  3  and a door  5  comprising a detergent dispenser  7 . As illustrated in  FIG. 1 , the dishwasher  1  comprises a wash arm arrangement  9  with a rotatable first wash arm  11  arranged to rotate around a first rotation axis a 1  within the washing chamber  3 . The rotatable first wash arm  11  can also be referred to as first wash arm. 
     According to the embodiment illustrated in  FIG. 1 , the dishwasher  1  comprises a rack  10  arranged to accommodate items (not shown) to be washed in the dishwasher  1 . The wash arm arrangement  9  may be fastened to the rack  10  by attachment means  12 . A position change of the rack  10 , e.g. between an upper and a lower position, will result in a position change of the wash arm arrangement  9 . 
     The wash arm arrangement  9  comprises a second wash arm  13  which is rotatably attached to the first wash arm  11  and is arranged to rotate around a second rotation axis a 2 . Thus, the entire second wash  13  arm will be rotated via the first wash arm  11  during operation of the dishwasher  1 . Further, because the second wash arm  13  is rotatably attached to the first wash arm  11 , the second wash arm  13  may rotate around the second rotation axis a 2  while the first wash arm  11  rotates around the first rotation axis a 1 . 
     The first rotation axis a 1  and the second rotation axis a 2  are arranged at a distance c from each other. The distance c and a length of the second wash arm  13  are selected such that the second arm  13  is allowed to rotate in an unobstructed manner around the second rotation axis a 2 . 
     A washing liquid pipe  14  may be arranged to feed washing liquid to the wash arm arrangement  9 . The washing liquid pipe  14  may be arranged with a first end  16  arranged towards a washing liquid supply or connection (not shown) and a second end  18  arranged as an attachment portion for the first wash arm  11 . The washing liquid pipe  14 , the first wash arm  11  and the second wash arm  13  may be arranged as hollow bodies. 
     The first wash arm  11  and the second wash arm  13  may comprise a number of nozzles  17  arranged to expel washing liquid towards the items at the rack  10  to wash and/or rinse the items. The first wash arm  11  and/or the second wash arm  13  may comprise further nozzles (not shown), which are arranged to expel washing liquid such that rotation of the first and/or second wash arm(s)  11 ,  13  are achieved. In some embodiments, rotation of the first and/or second wash arm(s)  11 ,  13  are provided by means of an electric motor (not shown). 
     The second wash arm  13  also comprises a spray nozzle  15  arranged to expel washing liquid into the washing chamber  3 . The spray nozzle  15  can also be referred to as dedicated detergent dispenser nozzle which is arranged to rinse the detergent dispenser  7  during operation of the dishwasher  1 . The spray nozzle  15  has both the function of rinsing the detergent dispenser  7  and to cause the second wash arm  13  to be rotated. The spray nozzle  15  is arranged to be directed towards the detergent dispenser  7  in a direction d having a first angle α, described below, and a second angle β relatively a rotation plane p of the second wash arm  13 . The spray nozzle  15  is directed towards the detergent dispenser  7  in the direction d during at least a portion of a rotation cycle of the second wash arm  13  and during at least a portion of some of rotational cycles of the first spray arm  11 . The portions of the rotational cycles of the first wash arm  11  and the second wash arm  13  may, for example relate to a time range or to a part of the rotational cycles. 
     As illustrated in  FIG. 1 , angle β is sharp relatively the plane p in the  FIG. 1  embodiment. Thus, the angle β is an angle between the direction d and the plane p in a vertical plane extending through the direction d and an orthogonal projection of the direction d on the plane p. When the nozzle  15  is directed towards the detergent dispenser  7 , as illustrated in  FIG. 1 , the angle β is thus the angle between the direction d and the plane p. The angle β may have substantially the same magnitude during rotation of the second wash arm  13 . When the second wash arm  13  is rotated the spray nozzle  15  will be brought along a circular path, further illustrated in conjunction with  FIGS. 3 and 4 . 
     As illustrated in  FIG. 1 , the spray nozzle  15  is arranged to be directed towards the detergent dispenser  7 , thereby causing the washing liquid to intersect with, or hit, the detergent dispenser  7 . 
     The angle β is chosen such that a beam of washing liquid ejected by the spray nozzle  15  in the direction d hits the detergent dispenser  7  during at least a portion of the rotational cycles of the first wash arm  11  and the second wash arm  13 . Thus, a major portion or a core portion of the beam ejected by the spray nozzle  15  is controlled to enter interior surfaces of the detergent dispenser  7  while the beam passes the detergent dispenser  7  during at least a portion of the rotation cycles of the first wash arm  11  and the second wash arm  13 . Thereby, the spray nozzle  15  is dedicated to expel washing liquid towards the detergent dispenser  7  in contrast to the nozzles  17  which mainly direct the washing liquid towards items accommodated at the rack  10  in order to wash and/or rinse the items. Hereby the detergent dispenser  7  will be rinsed more efficiently than if only rinsed by any washing liquid scattered within the washing chamber of the dishwasher  1 . It is hereby ensured that no residual washing powder or liquid detergent is left in the detergent dispenser  7 . Accordingly, both efficient rinsing, and avoidance of clogging within the detergent dispenser  7  is achieved by a sole spray nozzle  15 . The spray nozzle  15  is arranged to be directed towards the detergent dispenser  7  during at least a portion of the rotation cycles of the first wash arm  11  and the second wash arm  13  to cause the washing liquid to intersect with the detergent dispenser  7 . Thus, the spray nozzle  15  is arranged to be directed towards the detergent dispenser  7  for at least a predetermined amount of time of at least a predetermined subset of rotation cycles of a dishwasher washing program or similar. When not directed towards the detergent dispenser  7 , the spray nozzle  15  may be configured to wash and/or rinse other parts within the dishwasher chamber  3 . 
     According to the embodiment illustrated in  FIG. 1  the detergent dispenser  7  is positioned downwards relatively the plane p. It is understood that “downwards” here relates to a direction when the dishwasher  1  is arranged in a normal operating position where a lower portion with a sink or similar is arranged downwards. Upwards is thus the opposite direction, facing towards an upper portion of the dishwasher  1 . Therefore, the spray nozzle  15  is directed downwards in the second angle β relatively the plane p. The second angle β may be in the range of 1-60 degrees. The second angle β is selected such that the washing liquid hits the detergent dispenser  7  when expelled through the spray nozzle  15 . 
     As illustrated in  FIG. 1 , the dishwasher  1  may comprise a second rack  20  adapted to accommodate items (not shown) to be washed in the dishwasher  1  and a lower wash arm arrangement  19 . Thus, the wash arm arrangement  9  in  FIG. 1  is an upper wash arm arrangement, arranged to be mounted above the lower wash arm arrangement  19 . The rack  10  may be referred to as an upper rack and the second rack  20  may be referred to as a lower rack. Thus, the spray nozzle  15  is arranged to, when not directed towards the detergent dispenser  7 , wash and/or rinse other parts within the dishwasher chamber  3 , such as items (not shown) on the rack  20 . 
       FIG. 2  illustrates the wash arm arrangement  9  according to an alternative embodiment. As described in conjunction with  FIG. 1 , the wash arm arrangement  9  comprises the first wash arm  11  and the second wash arm  13 . The second wash arm  13  comprises the spray nozzle  15  which is arranged to expel washing liquid into the washing chamber  3 . According to the embodiment illustrated in  FIG. 2 , the spray nozzle  15  is arranged to be directed towards the detergent dispenser  7  in a direction d having a second angle β relatively the plane p, wherein the second angle β is directed upwards relatively the plane p. Thereby, the detergent dispenser  7  can also be efficiently rinsed when it is arranged at a position above the plane p. As illustrated in  FIG. 2 , angle β is sharp relatively the plane p in some embodiments herein. 
     The wash arm arrangement  9  may be arranged as a middle or an upper wash arm arrangement within the washing chamber of the dishwasher. The spray nozzle  15  is arranged to be directed towards the detergent dispenser  7  during at least a portion of the rotation cycles of the first wash arm  11  and the second wash arm  13  to cause the washing liquid to intersect with the detergent dispenser  7 . Thus, the spray nozzle  15  is arranged to be directed towards the detergent dispenser  7  for at least a predetermined amount of time of at least a predetermined subset of rotation cycles of a dishwasher washing program or similar. The spray nozzle  15  is arranged to, when not directed towards the detergent dispenser  7 , to wash and/or rinse other parts within the dishwasher chamber  3 , such as items on a rack arranged above the wash arm arrangement  9 . Similarly to the embodiment illustrated in  FIG. 1 , with the second angle β directed downwards, the second angle β, according to the embodiment in  FIG. 2 , may be in the range of 1-60 degrees. The second angle β is selected such that the washing liquid hits the detergent dispenser  7  when expelled through the spray nozzle  15 . 
       FIG. 3  illustrates the wash arm arrangement  9 , the rotatable first wash arm  11 , the second wash arm  13  and the spray nozzle  15  from above. The second wash arm  13  is arranged to bring the spray nozzle  15  along a circular path with a radius r. The circular path is illustrated with dashed lines in  FIG. 3 . When both the first wash arm  11  and the second wash arm  13  are rotated the entire circular path will be rotated around the rotation axis of the first wash arm  11 . The spray nozzle  15  is arranged to rotate in the plane denominated pin  FIG. 1  during rotation cycles of the second wash arm  13 . The spray nozzle  15  is arranged to be directed towards the detergent dispenser  7  in a direction d having a first angle α relatively the radius r and arranged to cause the washing liquid to intersect with, or hit, the detergent dispenser  7  during at least a portion of some of the rotation cycles. According to the embodiment illustrated in  FIG. 3  the first angle α is in the range of 0-89 degrees, however the first angle α may also be in the range of 45-89 degrees. In the embodiment depicted in  FIG. 3  the first angle α is thus sharp. In other words, the washing liquid will be expelled by the spray nozzle  15  in the direction d inwards relatively the circular path. 
     The embodiment illustrated in  FIG. 4  resembles the embodiment illustrated in  FIG. 3  but in this embodiment the first angle α is blunt. The first angle α may be in the range of 91-135 degrees. In other words, the washing liquid will be expelled by the spray nozzle  15  in a direction d outwards relatively the circular path. 
     In the embodiments illustrated in  FIG. 3  and  FIG. 4  the rotatable first wash arm  11  is arranged to rotate at a first velocity v 1  and the second wash arm  13  is arranged to rotate at a second velocity v 2 . Since the first velocity v 1  may be different from the second velocity v 2 , the first wash arm  11  and the second wash arm  13  will have different mutual positions for different rotational cycles of the second wash arm  13 . 
     According to some embodiments the wash arm arrangement  9  may be arranged to be displaceable between a first position and a second position where the first position and the second position being different height positions within the washing chamber  3 . The wash arm arrangement  9  may be arranged to be attached to an upper rack, denominated  10  in  FIG. 1 . The wash arm arrangement  9  may thereby be positioned in an upper position when the rack  10  is positioned in an upper position and in a lower position when the rack  10  is positioned in a lower position. The lower positions and the upper positions here refer to different height positions of the same rack and wash arm arrangement. Thereby, user may displace the wash arm arrangement  9  and the upper rack  10  to adapt the dishwasher to items to be washed and to be accommodated at the rack  10  and at a rack denominated  20  in  FIG. 1 . Spray paths/patterns for different height positions, i.e. the upper position and the lower position are further discussed in conjunction with  FIG. 5 . 
       FIG. 5  illustrates paths s 1  and s 2 . Paths s 1  and s 2  represent a pattern that beams of washing liquid ejected from a nozzle at a traditional wash arm will cause on a door  5  of a dishwasher. The path s 1  is achieved when the traditional wash arm is arranged in an upper position and the path s 2  is achieved when the traditional wash arm is arranged in a lower opposition. As depicted in  FIG. 5  only one of the paths s 1  and s 2  with relative long horizontal extension and relatively short vertical extension for each of the upper and lower positions are achieved. Only the beam of washing liquid at the lower position, along the path s 2  of the traditional wash arm, hits the detergent dispensed  7 . When the traditional wash arm is positioned in the upper position the path s 1  does not intersect with or hit the detergent dispenser  7 . Hereby the detergent dispenser  7  will only be rinsed by any “ambient” washing liquid scattered around in the washing chamber. 
     Paths t 1  and t 2  illustrate patterns caused by a spray nozzle according to embodiments herein. As illustrated in  FIG. 5  a larger amount of paths are achieved as compared to the paths s 1  and s 2  achieved by a traditional wash arm. Thereby, noise caused when the beams of washing liquid traveling along paths t 1  and t 2  hit the door  5  by will have a pulsating character. Noise caused when the beams of washing liquid traveling along paths s 1  and s 2  on the door  5  will have a continuous character. The pulsating character of the noise may be preferable as it more clearly indicates that the dishwasher is in use and may be less perceived as background noise. 
     In some embodiment the wash arm arrangement is arranged to be displaceable between a first position and a second position, the first position and the second position being different height positions within the washing chamber. 
     The path t 1  is achieved at the first, here upper, position and the path t 2  is achieved at the second, here lower, position of the wash arm arrangement. The paths t 1  and t 2  have a reverse U-form having a horizontal extension and a vertical extension. The number of paths t 1  and t 2  on the door  5  is a function that depends on a ratio between the first velocity and the second velocity of the first wash arm and the second wash arm respectively. The horizontal extension of path t 1  and t 2  can be controlled e.g. by adjustment of the first velocity, the second velocity or the ratio between the first velocity and the second velocity. The horizontal extension of path t 1  and t 2  can be adjusted such that at least one of paths t 1  and t 2  hits the detergent dispenser  7  on the door  5 . 
     Also the vertical extension of the paths t 1  and t 2  are a function of the first velocity and the second velocity of the first wash arm and the second wash arm respectively. Further, the horizontal extension and the vertical extension of the paths t 1  and t 2  are a function of the first angle α and the second angle β. Both the horizontal extension and the vertical extension of the paths t 1  and t 2  may be controlled by adjustment of the first velocity and the second velocity of the first wash arm and the second wash arm. Further the horizontal extension and the vertical extension of the paths t 1  and t 2  may also be controlled by selection of the first angle and the second angle based on the position of the detergent dispenser for a particular type of dishwasher. 
     The vertical extension of the paths t 1  and t 2  depends to a large extent on the second angle β. A relatively large second angle β provides for a relatively long vertical extension of the paths t 1  and t 2 . 
     As illustrated in  FIG. 5 , the detergent dispenser  7  is hit by a beam of washing liquid ejected from the spray nozzle both when the wash arm arrangement is in the first, upper position, illustrated by the path t 1  and in the second, lower, position, illustrated by the path t 2 . Therefore a sole spray nozzle according to embodiments herein is capable to efficiently rinse the detergent dispenser  7  independently of whether the wash arm arrangement is positioned within the first or second position, i.e. independently of the relative height between the second wash arm and the detergent dispenser. 
     Paths t 1  and t 2  can also be referred to as intersection paths. The reverse U-shape is at least partly caused by the fact that the spray nozzle expels the washing liquid upwards or downwards relatively the rotation plane of the second spray arm. Expelled washing liquid will not hit the door substantially perpendicularly, but is instead controlled to travel in a bow-shape. The vertical extension of paths t 1  and t 2  are therefore larger than a vertical extension of paths s 1  and s 2 . In some embodiments the vertical extension on a path, or intersection path, is controlled to have a predetermined minimum extension.