WO2022143787A1

WO2022143787A1 - Spray system for a dishwasher

Info

Publication number: WO2022143787A1
Application number: PCT/CN2021/142549
Authority: WO
Inventors: Sebastian Jan Chwalibog
Original assignee: Midea Group Co Ltd
Current assignee: Midea Group Co Ltd
Priority date: 2020-12-30
Filing date: 2021-12-29
Publication date: 2022-07-07
Anticipated expiration: 2023-06-30
Also published as: EP4023135A1

Abstract

A spray system for spraying a fluid in a dishwasher (100), the spray system comprising: a rotatable hub (202); and one or more spray arms (204, 206) comprising one or more nozzles (222); wherein the spray arms (204, 206) are rotatablely mounted to the hub (202), and wherein, in operation of the spray system, the hub (202) rotates around a first rotation axis (208) and each spray arm (204, 206) rotates around a second rotation axis (210).

Description

SPRAY SYSTEM FOR A DISHWASHER

TECHNICAL FIELD

The present disclosure relates to a spray arm for dispersing a fluid in a volume. The spray arm can be used in a dishwasher, to disperse water over a plurality of objects.

BACKGROUND

The task of spraying a fluid onto an arbitrarily shaped object is relevant in a plurality of applications, including dishwashers, garden sprinklers, and car wash facilities. Existing solutions include rotating arms bearing nozzles that eject a fluid. These rotating arms allow the nozzles to move, and thereby, the fluid is sprayed from a plurality of different positions. However, as the nozzles are fixed on each arm, each nozzle sprays the fluid only in one direction. Therefore, a need exists to increase the complexity of the fluid spray.

CN111227751A, CN205338873U, CN206950137U, CN110859566A, CN203789884U, CN111297293U disclose spray arms for dishwashers.

SUMMARY

Disclosed and claimed herein is a spray system for spraying a fluid in a dishwasher.

The present disclosure relates to a spray system for spraying a fluid in a dishwasher. The spray system comprises a rotatable hub and one or more spray arms comprising one or more nozzles. The spray arms are rotatably mounted to the hub. In operation of the spray system, the hub rotates around a first rotation axis and each spray arm rotates around a second rotation axis. The rotation around the first rotation axis may be caused by a first driving means, e.g. a motor.

The rotation around the first rotation axis causes a continuous change in the position of the nozzles, i.e. the position from which the flow emanates. The rotation around the second rotation axis causes a continuous change in the angle at which the flow emanates from the nozzle. Thereby, the complexity of the flow of the fluid is increased, and the flow better reaches objects with non-uniform surfaces. The rotation around the second rotation axis may be caused, for example, by a second driving means, such as a motor, which may be independent from the first driving means.

In an embodiment, in operation of the spray system, a rotation of the hub around the first rotation axis causes the spray arm to rotate around the second rotation axis.

The rotational movements are thus simultaneous, thereby increasing the complexity of the flow, i.e. the entropy in the flow parameters. The rotation around the second axis does not need an external driver, such as a motor. Rather, mechanical forces are translated from the rotation around the first axis to the rotation around the second axis. The translation may be caused by a set of gears in an exemplary embodiment. This allows implementing the spray system of the present disclosure by modifying the spray arms of an existing spray system with only limited modification of other parts.

In a further embodiment, the hub is attachable to a first support via a first bearing, and the first bearing is configured to enable a rotation of the hub around the first rotation axis. In yet a further embodiment, each spray arm is mounted to the hub via a second bearing at a proximal end of the spray arm, the second bearing is configured to enable a rotation of the spray arm around the second rotation axis. A bearing reduces the friction upon rotation. The use of bearings is, however, optional, and snapping connections may also be used, as long as the connections allow rotation.

In a further embodiment, the first bearing and/or the second bearing is a ball bearing. A ball bearing allows reducing the friction in the bearings, and thus the mechanical strain and the wear are reduced.

In a further embodiment, the second rotation axis extends from the proximal end to a distal end of the spray arm. Thereby, the space occupied by the spray arm itself is reduced at high complexity of the flow.

In a further embodiment, and the second rotation axis is substantially perpendicular to the first rotation axis. Thereby, the spray arms spray into the direction of the first axis when the rotation angle is zero degrees, and are configured to turn in order to increase the complexity of the spray.

In a further embodiment, the spray system further comprises one or more first protrusions disposed on a second support. In said embodiment, the first protrusions, disposed on the second support, engage with the edges of the spray arms to cause the spray arm to rotate around the second rotation axis.

In yet a further embodiment, the spray system may comprise one or more second protrusions disposed on the spray arms, in addition to the first protrusions disposed on the second support. The rotation of the spray arms around the second axis is then caused by either the protrusions engaging with each other, or the first protrusions engaging with the spray arms, or a combination thereof. The size and/or shape of the first protrusions and second protrusions may determine a minimum angle by which the spray arms are rotated. Rotation of the spray arms may be caused at first by the displacement of the spray arm when engaging with the protrusion, but the angular momentum conferred to the spray arm by said motion may cause a further rotation. The further rotation may optionally be blocked by a hard stop, or prevented by gravity, or spray recoil, as detailed below.

In general, the second support may be a static support that does not rotate with the spray arms. During operation, the spray arms move along the second support. When in contact, the first and/or second protrusions deflect the force generated by the rotation around the first rotation axis into a perpendicular direction. This mechanism allows a simple construction, and thereby avoids unnecessary complexity. However, in an alternative embodiment, the second support may be able to rotate slowly around the first rotation axis. Thereby, the perpendicular motion is initiated at a different angular position, thereby further increasing the complexity of the flow. Such a rotation may be caused by the rotation of the hub and the spray arms or externally driven. The second support may preferably rotate in the opposite direction as the hub, but it may alternatively rotate into the same direction, but at a different speed.

In a further embodiment, the second support is comprised in or attached to the first support. Thereby, one and the same part of the spray system may comprise different features and thereby have multiple functions. By including these parts into one single piece, the complexity of the spray system in further reduced. Also, the first and second support and the blocking element may be combined in one piece.

In a further embodiment, the support is a nut, attached to a manifold of a dishwasher. In a further embodiment, the support is attached to a basket of a dishwasher. The spray system may therefore be suspended by the manifold, and spray objects in baskets above and below. Any part of the system may be integrated into existing features of a dishwasher, thereby reducing the complexity of the construction.

In a further embodiment, the spray system further comprises a blocking element configured to provide a hard stop to restrain the rotation of the spray arm around the second rotation axis to a maximum angle. If the spray arms have the shape of a flat blade, i.e. if its dimensions are more extended in its plane of rotation than perpendicularly to it, then the hard stop may comprise a ring disposed around the first rotation axis. The ring then prevents the blade to rotate further than to a maximum angle. The position of the blocking element thereby determines the maximum angle, and may be fixed or adjustable during operation.

In a further embodiment, the blocking element is comprised in or attached to the first support and/or second support. The first support and/or second support may be made of a single piece of molded polymer, providing a supply for the fluid and carrying the first bearing, and may be appropriately shaped to provide the hard stop to block the rotation around the second axis in excess of a maximum angle, as described above.

In a further embodiment, the blocking element is comprised in or attached to a funnel, or a manifold of the dishwasher. Combination of these elements further reduces complexity both in design of an embodiment and in production.

In a further embodiment, the rotation of the spray arm involves rotation in two directions. In a further embodiment, the rotation of the spray arm is further caused by gravity and/or spray recoil from the nozzles. Thereby, the construction is further simplified. The protrusions on the spray arms and on the second support only initiate the rotation around the second rotation axis in one direction, and the restoring force for the return into the original position is provided by gravity and/or spray recoil. Thereby, the complexity of the system is reduced.

In a further embodiment, the fluid is a liquid. In a further embodiment, the fluid is water, or a water-based solution. The spray system may be used for a number of applications, such as a garden sprinkler, a car wash, or a dishwasher. However, also different uses are possible. For example, an embodiment may relate to dispersing a gas and/or mixing gases.

In a further embodiment, the rotation of the hub is hydraulically or pneumatically driven. Thereby, the pressure of the fluid sprayed does itself drive both rotations, thereby eliminating the need for an additional motor.

In a further embodiment, the nozzles are configured to eject the fluid into different directions relative to the spray arm. This further increases the complexity of the flow.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, objects, and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference numerals refer to similar elements.

Figure 1 depicts a drawing of a dishwasher comprising a spray system;

Figure 2A represents a drawing of a first spray system;

Figure 2B represents a drawing of a detail of the first spray system;

Figure 2C represents a drawing of a further detail of the first spray system;

Figure 2D represents an exploded view drawing of the first spray system;

Figure 3A represents a drawing of a second spray system;

Figure 3B represents a drawing of a detail of the second spray system;

Figure 3C represents a drawing of a further detail of the second spray system;

Figure 3D represents an exploded view drawing of the second spray system;

Figure 4A represents a drawing of a third spray system; and

Figure 4B represents a drawing of a third spray system wherein the spray arms are in a different position.

DETAILED DESCRIPTION

Figure 1 represents a drawing of a dishwasher 100 according to an embodiment of the present disclosure. The dishwasher 100 comprises a first spray system 102 according to the embodiment described with respect to Figures 2A-2D below. The dishwasher further comprises a second spray system 104 according to the embodiment described with respect to Figures 3A-3D below. The second spray system 104 may be attached to a basket 106 for storing the dishes to be washed.

First embodiment

Figure 2A represents a drawing of a first spray system 200, according to a first embodiment of the present disclosure. The first spray system 200 comprises a hub 202 and, in this exemplary embodiment, two spray

arms

204, 206. However, in other embodiments, the spray system 200 may comprise another number of spray arms. The hub 202 is configured to rotate around a first rotation axis 208. Thereby, the two

spray arms

204, 206 revolve around the first rotation axis 208. At the same time, each spray arm is configured to perform a second rotation around a second rotation axis 210. The second rotation axis extends from the proximal end, i.e. the base end of each spray arm to its distal end, i.e. its tip. Thus, in principle, the second rotation axis is different for each spray arm. In a different embodiment, for example, the spray system may comprise five spray arms, each of which has its own second rotation axis. These rotation axes do, however, have in common that all of them are, at least substantially, perpendicular to the first rotation axis. In yet another embodiment, the spray arms may be attached to the hub in a way that they are tilted away from the normal, such that they cover a cone when revolving around the first rotation axis, rather than a plane. In that case, also the second axes describe a cone, similar to the second embodiment shown in Figure 3A. Furthermore, the rotation may be limited to a maximum angular range as described below. The

spray arms

204, 206 comprise nozzles as discussed below.

Figure 2B represents a drawing of a detail of the first spray system 200. The spray arm 204 is shown in a horizontal position, i.e. at zero degrees rotation angle of the rotation around the second rotation axis. The spray arm 206 is shown in a tilted position, i.e. rotated at a non-zero rotation angle around the second rotation axis. The

spray arms

204, 206 are only connected via the hub, and therefore rotate independently around the second rotation axes.

On the second support 212, one or more first protrusions 214 are disposed. There are also second protrusions 216 disposed on the spray arm 206 and second protrusions on the spray arm 204. During operation, the hub rotates around the first rotation axis, and the second protrusions 216 on the spray arms move along the rim of the second support 212. Once they reach the first protrusions 214 disposed on the second support, the first and

second protrusions

214, 216 engage with each other and cause the spray arm to rotate around the second rotation axis, in one direction, as shown. As the hub continues to rotate around the first axis, the first and

second protrusions

214, 216, disengage. Then, the spray arm moves back to zero rotation angle. This restoring movement may be caused by gravitation, as the weight of the spray arm is symmetrically distributed with respect to the second rotation axis. The restoring movement may further be caused or assisted by the contact between the first protrusions 214 on the second support 212 and the second protrusions 216 on the

spray arms

204, 206, as well as by the contact of the first protrusions 214 with the edges of the

spray arms

204, 206. This may be further assisted by the recoil force of the nozzles 222 (Fig. 2D) if the nozzles have a symmetric directionality.

The rim of the funnel element (second support 212) here also serves as a blocking element to restrain the rotation of the spray arms. As shown, spray arm 206 is prevented from further rotating by the blocking element. However, in other embodiments, the blocking element may be positioned independently from the second support 212. The maximum angular range covered by the

spray arms

204, 206 is defined by the positioning of the blocking element. In particular, the blocking element may be designed by choosing an appropriate maximum angle for the rotation around the second rotation axis, calculating an according position for the blocking element using angular functions, and positioning the blocking element. This may be done using design of an embodiment, but the blocking element may be configurable such that the maximum angle can be changed after fabrication. The blocking element may also be displaceable during operation.

Figure 2C represents a drawing of a further detail of the first spray system 200.

Figure 2D represents an exploded view drawing of the first spray system 200. The hub 202 is disposed on a first support 218. In this exemplary embodiment, the sump cavity serves as a first support 218. A funnel component serves as second support 212. The

spray arms

204, 206 are attached to the hub 202 via second bearings 220 and comprise a plurality of nozzles, 222. The nozzles 222 spray water into a plurality of directions relative to the spray arm.

Second embodiment

The second embodiment (Fig. 3A-3D) relates to a spray arm related to a basket in an upper part of a dishwasher. As far as not described differently, the properties and advantages of the first embodiment also apply to the second embodiment.

Figure 3A represents a drawing of a second spray system 300, according to a second embodiment of the present disclosure. The second spray system 300 comprises a hub 302 and, in this exemplary embodiment, two spray

arms

304, 306. The hub 302 is configured to rotate around a first rotation axis 308. Thereby, the two

spray arms

304, 306 revolve around the first rotation axis 308. At the same time, each spray arm is configured to perform a second rotation around a second rotation axis 310. The

spray arms

304, 306 comprise nozzles as discussed below. The

spray arms

304, 306 are tilted downwards, so that they form an oblique angle to the first rotation axis. However, the axes are substantially perpendicular.

Figure 3B represents a drawing of a detail of the second spray system 300.

Figure 3C represents a drawing of a further detail of the second spray system 300. The

spray arms

304, 306 are shown in a horizontal position, i.e. at zero degrees rotation angle of the rotation around the second rotation axis. On the second support 312, one or more protrusions 314 are disposed. There are also second protrusions 316 disposed on the spray arm 306 and second protrusions (not shown in Fig. 3C) on the spray arm 304. As shown, the second protrusions 316 disposed on the spray arm 306 are about to engage the first protrusions on the second support. The nut (second support 312) here also serves as a blocking element, limiting the angle of rotation of the spray arms.

Figure 3D represents an exploded view drawing of the second spray system 300. The hub 302 is connected to a first support 318. In this exemplary embodiment, the manifold serves as a first support 318. A nut serves as second support 312. The

spray arms

304, 306 are attached to the hub 302 via second bearings 320, and comprise nozzles 322.

Third embodiment

Figures 4A and 4B represent drawings of a third spray system 400, according to a third exemplary embodiment. As far as not described differently, the properties and advantages of the first embodiment also apply to the third embodiment. The hub 402 rotates around the first rotation axis 414. The spray arm 404 is mounted on hub 402 asymmetrically, so that the spray arm is inclined to the right if at rest. Upon operation, however, the spray arm is displaced by the

first protrusions

408, 410 on the second support 406, and receives an angular momentum that causes further rotation around the second rotation axis 412.

Figure 4A depicts the spray arm at its largest angle of the rotation around its second axis. A typical value is 12 to 15 degrees. After reaching the maximum angle of rotation, the spray arm is returned by gravity. Since the spray arm is asymmetric, i.e. the spray arm extends more to the right from the second axis 412 as shown, the position is restored by gravity.

Figure 4B shows the spray arm after partial restoration of the position.

Fourth embodiment

In a fourth exemplary embodiment (not shown) , the rotation of the hub around the first axis is generated by a first driving means, as in the other embodiments. However, the fifth embodiment comprises a motor, acting as a second driving means that causes the rotation of the spray arms around the second axis. The second driving means is actuated and controlled independently from the first driving means.

Fifth embodiment

In a fifth exemplary embodiment (not shown) , the spray system comprises a set of gears that acts as a transmission means. The set of gears transmits a rotation force from the rotation of the hub around the first axis to the spray arms. This causes the spray arms to rotate around the second axis.

Further Examples

Example 1. A spray system for spraying a fluid in a dishwasher, the spray system comprising:

a rotatable hub (202) ; and

one or more spray arms (204, 206) comprising one or more nozzles (222) ;

wherein the spray arms (204, 206) are rotatably mounted to the hub (202) , and

wherein, in operation of the spray system, the hub (202) rotates around a first rotation axis (208) and each spray arm (204, 206) rotates around a second rotation axis (210) .

Example 2. The spray system of example 1,

wherein, in operation of the spray system, a rotation of the hub (202) around the first rotation axis (208) causes the spray arms (204, 206) to rotate around the second rotation axis (210) .

Example 3. The spray system of example 1 or 2,

wherein the hub (202) is attachable to a first support (218) via a first bearing, and

wherein the first bearing is configured to enable a rotation of the hub (202) around the first rotation axis (208) .

Example 4. The spray system of any preceding example,

wherein each spray arm (204, 206) is mounted to the hub (202) via a second bearing (220) at a proximal end of the spray arm (204, 206) ,

wherein the second bearing (220) is configured to enable a rotation of the spray arm (204, 206) around the second rotation axis (210) .

Example 5. The spray system of example 3 or 4,

wherein the first bearing and/or the second bearing (220) is a ball bearing.

Example 6. The spray system of any preceding example,

wherein the second rotation axis (210) extends from the proximal end to a distal end of the spray arm (204, 206) .

Example 7. The spray system of any preceding example,

wherein the second rotation axis (210) is substantially perpendicular to the first rotation axis (208) .

Example 8. The spray system of any preceding example, further comprising one or more first protrusions (214) disposed on a second support (212) ,

wherein the first protrusions (214) engage with one or more edges of the spray arms (204, 206) to cause the spray arms (204, 206) to rotate around the second rotation axis (210) .

Example 9. The spray system of example 8,

further comprising one or more second protrusions (216) disposed on the spray arms (204, 206) ,

wherein the first protrusions (214) engage with one or more edges of the spray arms (204, 206) and/or with the second protrusions (216) to cause the spray arms (204, 206) to rotate around the second rotation axis (210) .

Example 10. The spray system of example 8 or 9,

wherein the second support (212) is configured to rotate around the first axis.

Example 11. The spray system of any of examples 8-10,

wherein the second support (212) is comprised in or attached to the first support (218) .

Example 12. The spray system of any preceding example,

wherein the first and/or second support (212) is a nut, attached to a manifold of the dishwasher.

Example 13. The spray system of any example,

wherein the first and/or second support (212) is attached to a basket of the dishwasher.

Example 14. The spray system of any preceding example,

wherein the first and/or second support (212) is attached to a sump cavity of the dishwasher.

Example 15. The spray system of any preceding example,

further comprising a blocking element configured to provide a hard stop to restrain the rotation of the spray arm (204, 206) around the second rotation axis (210) to a maximum angle.

Example 16. The spray system of example 15,

wherein the blocking element is comprised in or attached to the first support (218) and/or second support (212) .

Example 17. The spray system of example 15 or 16,

wherein the blocking element is comprised in or attached to a funnel, a docking tube, spray arm nut, or a manifold of the dishwasher.

Example 18. The spray system of any preceding example,

wherein the rotation of the spray arm (204, 206) involves rotation in two directions.

Example 19. The spray system of any preceding example,

wherein the rotation of the spray arm (204, 206) is further caused by gravity and/or spray recoil from the nozzles (222) .

Example 20. The spray system of any preceding example,

wherein the fluid is a liquid.

Example 21. The spray system of any preceding example,

wherein the fluid is water, or a water-based solution.

Example 22. The spray system of any preceding example,

wherein the rotation of the hub (202) and/or the rotation of the spray arms (204, 206) is hydraulically or pneumatically driven.

Example 23. The spray system of example 1,

wherein the rotation of the hub (202) is caused by a first driving means, and the rotation of the spray arms (204, 206) is caused by a second driving means, wherein the first driving means is independent from the second driving means.

Example 24. The spray system of example 23,

wherein the first and/or the second driving means is a motor.

Example 25. The spray system of any of examples 1-7, further comprising a transmission means, wherein the transmission means is configured to translate the rotation of the hub (202) around the first rotation axis (208) into rotation of the spray arms (204, 206) around the second rotation axis (210) .

Example 26. The spray system of example 25, wherein the transmission means is a set of gears.

Example 27. The spray system of any preceding example,

wherein the nozzles (222) are configured to eject the fluid into different directions relative to the spray arm (204, 206) .

Example 28. A dishwasher, comprising the spray system of any preceding example.

Reference signs

100 Dishwasher

102 First spray system

104 Second spray system

106 Basket

200 First spray system

202 Hub

204, 206 Spray arms

208 First rotation axis

210 Second rotation axis

212 Second support

214 First protrusions, disposed on the second support

216 Second protrusions, disposed on the spray arms

218 First Support

220 Second bearing

222 Nozzles

300 Second spray system

302 Hub

304, 306 Spray arms

308 First rotation axis

310 Second rotation axis

312 Second support

314 First protrusions, disposed on the second support

316 Second protrusions, disposed on the spray arms

318 First Support

320 Second bearing

322 Nozzles

400 Third spray system

402 Hub

404 Spray arm

406 Second support

408, 410 First protrusions, disposed on the second support

412 Second rotation axis

414 First rotation axis.

Claims

A spray system for spraying a fluid in a dishwasher, the spray system comprising:

a rotatable hub (202) ; and

one or more spray arms (204, 206) comprising one or more nozzles (222) ;

wherein the spray arms (204, 206) are rotatably mounted to the hub (202) , and

wherein, in operation of the spray system, the hub (202) rotates around a first rotation axis (208) and each spray arm (204, 206) rotates around a second rotation axis (210) .
The spray system of claim 1, wherein, in operation of the spray system, a rotation of the hub (202) around the first rotation axis (208) causes the spray arms (204, 206) to rotate around the second rotation axis (210) .
The spray system of claim 1 or 2, wherein the hub (202) is attachable to a first support (218) via a first bearing, and wherein the first bearing is configured to enable a rotation of the hub (202) around the first rotation axis (208) , wherein the first bearing preferably is a ball bearing.
The spray system of any preceding claim, wherein each spray arm (204, 206) is mounted to the hub (202) via a second bearing (220) at a proximal end of the spray arm (204, 206) ,

wherein the second bearing (220) is configured to enable a rotation of the spray arm (204, 206) around the second rotation axis (210) , wherein the second bearing preferably is a ball bearing.
The spray system of any preceding claim, wherein the second rotation axis (210) extends from the proximal end to a distal end of the spray arm (204, 206) , and/or wherein the second rotation axis (210) is substantially perpendicular to the first rotation axis (208) .
The spray system of any preceding claim, further comprising one or more first protrusions (214) disposed on a second support (212) ,

wherein the first protrusions (214) engage with one or more edges of the spray arms (204, 206) to cause the spray arms (204, 206) to rotate around the second rotation axis (210) , and

in particular further comprising one or more second protrusions (216) disposed on the spray arms (204, 206) , wherein the first protrusions (214) engage with one or more edges of the spray arms (204, 206) and/or with the second protrusions (216) to cause the spray arms (204, 206) to rotate around the second rotation axis (210) .
The spray system of claim 6, wherein the second support (212) is configured to rotate around the first axis, and/or wherein the second support (212) is comprised in or attached to the first support (218) .
The spray system of any preceding claim, wherein the first and/or second support (212) is a nut, attached to a manifold of the dishwasher, and/or wherein the first and/or second support (212) is attached to a basket of the dishwasher, and/or wherein the first and/or second support (212) is attached to a sump cavity of the dishwasher.
The spray system of any preceding claim, further comprising a blocking element configured to provide a hard stop to restrain the rotation of the spray arm (204, 206) around the second rotation axis (210) to a maximum angle, and in particular wherein the blocking element is comprised in or attached to the first support (218) and/or second support (212) , and/or wherein the blocking element is comprised in or attached to a funnel, a docking tube, spray arm nut, or a manifold of the dishwasher.
The spray system of any preceding claim, wherein the rotation of the spray arm (204, 206) involves rotation in two directions, and/or wherein the rotation of the spray arm (204, 206) is further caused by gravity and/or spray recoil from the nozzles (222) .
The spray system of any preceding claim, wherein the fluid is a liquid, and in particular wherein the fluid is water, or a water-based solution.
The spray system of any preceding claim, wherein the rotation of the hub (202) and/or the rotation of the spray arms (204, 206) is hydraulically or pneumatically driven, or wherein the rotation of the hub (202) is caused by a first driving means, and the rotation of the spray arms (204, 206) is caused by a second driving means, wherein the first driving means is independent from the second driving means, and in particular wherein the first and/or the second driving means is a motor.
The spray system of any of claims 1-6, further comprising a transmission means, wherein the transmission means is configured to translate the rotation of the hub (202) around the first rotation axis (208) into rotation of the spray arms (204, 206) around the second rotation axis (210) , and in particular wherein the transmission means is a set of gears.
The spray system of any preceding claim, wherein the nozzles (222) are configured to eject the fluid into different directions relative to the spray arm (204, 206) .
A dishwasher, comprising the spray system of any preceding claim.