SE540512C2 - Spray arm for a dishwashing apparatus - Google Patents

Abstract

A rotatable spray arm (110, 111; 348) and a dishwashing apparatus (100). The spray arm comprises an elongated surface member (200,300) and an elongated casing (202,302) on both sides of a center section (203,303), the surface member (200,300) and the casing (202,302) are assembled together forming an inside chamber of the spray arm (110,111; 348). The inside chamber is divided in separate elongated washing channels (232-234, 235-237; 332-334, 335-337) provided on each side of the center section (203;303), said washing channels are connected to a dishwashing inlet (222;322) arranged to guide dishwashing liquid into the washing channels (232-234, 235-237; 332-334, 335-337) towards spray nozzles (212a-f;312a-g) at the end of each washing channel.

Description

SPRAY ARM FOR A DISHWASHING APPARATUS Technical Field The present disclosure relates to a spray arm for a dishwashing apparatus, and more particularly to a rotatable spray arm for a dishwashing apparatus and method for operating the same.

Background Dishwashers for heavily soiled articles to be washed, for example dishwashers for pots and pans , use liquid that is sprayed under high pressure towards the articles to be washed. In order to increase the field of application of the dishwashers, liquid may be circulated alternatively with and without granules. Thereby, the dishwashers may be used for washing both heavily soiled articles with granules and more sensitive ware, such as crockery, cutlery and glasses, without the granules.

US-A-5 667 431 describes a washing process for heavy-duty dishwashers, used in catering departments, wherein a mixture of washing water and blasting agent are sprayed under high pressure towards the articles to be washed. The washing process is begun by a pump pumping washing water with no blasting agent added. When the washing water has attained a suitable pressure and flow, blasting agent is added.

However, it has been difficult to control the amount of blasting agent in the washing water pumped through a conduit to a nozzle arrangement in the dishwashing compartment. The nozzle arrangement may have a number of nozzles adapted to spray the mixture of blasting agent and washing water towards the articles to be washed under high pressure.

Spray arms with a number of nozzles are desirable for distribution of wash liquid in a dishwasher. The mixture of washing water and blasting agent, for example granules, sprayed under high pressure, may cause various flow through the respective nozzle. One or more nozzles may become clogged up with granules and/or food particles in the dishwater, thereby greatly deteriorating the dishwashing result.

Summary It is an object of the teachings of this application to obviate at least some of the above disadvantages and to provide an improved rotatable spray arm for a dishwashing apparatus, and more particularly a rotatable spray arm with a number of spray outlets for a dishwashing apparatus providing essentially uniform liquid flow with granules through the spray outlets.

According to a first aspect, this is achieved by rotatable spray arm for a dishwashing apparatus, comprising an elongated surface member and an elongated casing on both sides of a center section, the surface member and the casing are assembled together forming an inside chamber of the spray arm, wherein the inside chamber is divided in separate elongated washing channels provided on each side of the center section, said washing channels are connected to a dishwashing inlet arranged to guide dishwashing liquid into the washing channels towards spray nozzles at the end of each washing channel.

In some embodiments, end portions of the separate washing channels have inclined, curved or rounded shape for guiding dishwashing liquid with or without granules at the end portions towards the nozzles for acceleration of the flow of liquid with or without granules In some embodiment, the separate washing channels are narrowing to increase the flow through out the nozzles.

In some embodiments the spray nozzles may be located at different individual distances from the center section.

In some embodiments, the washing channels have in cross section a shape corresponding substantially to any of a snip same side comer, snip comer, round same side comer, or round comer rectangle shape for preventing clogging of granules and/or food particles.

In some embodiments, the elongated surface member is arranged with a number of spray nozzles distributed along both sides of the center section, wherein the spray nozzles are disposed at any angle in relation to the length of the spray arm for creating a moving and rotational force by means of dishwashing liquid flowing through and out from the nozzles.

In some embodiments, the spray nozzles are advantageously disposed at any suitable angle of about 20° in relation to the length of the spray arm for appropriate rotational speed of the spray arm.

In some embodiments, the spray nozzles are projecting from the surface member, each nozzle having a cross section in the shape of an elongated rectangle with two opposite short sides and two opposite long sides, wherein two opposite short side walls and two opposite long side walls, wherein each opposite long side walls of each nozzle has an elongated concave cut-in portion, and the two opposite short side walls are rectangular.

Moreover, the long side walls of each spray nozzle may be convex and the short side walls and the long side walls may have a curved upper edge in some embodiments.

The particular shape of the nozzles may provide an advantageous spray pattern from the nozzles and self cleaning of the nozzles making an improved dishwashing effect.

In some embodiments, the nozzles have in cross section a shape corresponding substantially to an elongated rectangle of which the short sides of the rectangle are rounded or semicircular.

In some embodiments, the spray arm is arranged for dishwashing liquid including water or water and detergent.

In some embodiments, the spray arm is arranged for dishwashing liquid and granules.

In some embodiments, the inside chamber of the spray arm is provided with at least a rinsing channel in connection with a rinsing inlet for guiding rinsing liquid into said at least one rinsing channel arranged on each side of the center section for providing an even distribution of rinsing liquid through individual spray jets in the elongated surface.

In some embodiments, the spray jets for rinsing liquid are distributed along a first edge of the surface member one side of the center section and along an opposite second edge of the surface member on the other side of the center section, wherein the spray jets are inclined from the inside chamber towards the first edge or second edge along which the spray jets are distributed. Thereby, the spray arm will be rotating in dependence on the amount and pressure of the rinsing through the spray jets.

In some embodiments, the spray jets are advantageously inclined at any suitable angle of about 20°, in relation to the rotational axis of the spray arm when it is arranged in the dishwasher, for appropriate rotational speed of the spray arm, In some embodiments, a watertight sealing is arranged around the rinsing channel for preventing leakage of rinsing liquid and dishwashing liquid with or without granules between the rinsing channel and the dishwashing channels.

In some embodiments, the watertight sealing is an O-ring sealing arranged in a recessed flange on the inside of the surface member forming a tight sealing between the surface member and the casing of the assembled spray arm.

According to a second aspect, a dishwashing apparatus is provided, comprising at least one rotatable spray arm. The dishwashing apparatus may be a granule dishwasher arranged to circulate liquid alternatively with and without granules.

In some embodiments, the dishwashing apparatus comprises a granule valve arrangement including a granule basket removably arranged on a granule valve, said granule valve is arranged to be altered between a closed position, wherein a valve head covers an aperture in the bottom of the granule basket for collecting granules in the granule basket, and an open position, wherein the valve head is moved upwards such that granules can pass from the granule basket through the aperture in the bottom of the granule basket into the granule valve together with liquid for dishwashing.

According to a third aspect, a method for operating a dishwashing apparatus is provided, comprising initiating the liquid pump for providing liquid with low liquid pressure; detecting a ware holder adapted for coarse washing in the chamber, and that the granule basket is attached to the granule valve; controlling the granule valve to open for adding granules to the liquid; dishwashing, wherein liquid and granules are pumped from the washing tank through the at least one rotatable spray arm on to the ware holder; controlling the granule valve to close for collecting the granules in the granule basket; and rinsing the ware holder.

Other aspects and features of the invention and its embodiments are further explained in the detailed description and the drawings, and are defined by the appended claims.

It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps, or components, but does not preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof.

Brief Description of the Drawings Further objects, features and advantages will appear from the following detailed description of embodiments, with reference being made to the accompanying drawings, in which: FIG. 1 is a perspective view of a dishwashing apparatus according to an embodiment; FIG. 2 is a perspective view of a rotatable spray arm with outlets according to an embodiment for a dishwashing apparatus as shown in FIG. 1 ; FIG. 3 is a perspective view of a rotatable spray arm as shown in FIG. 1 with an inlet connection; FIG. 4 is a perspective view of one part of the rotatable spray arm as shown in FIG 2A with rinsing and washing channels; FIG. 5 is a locally enlarged perspective view of the rotatable spray arm as shown in FIG. 4; FIG. 6 is a perspective view of a rotatable spray arm with outlets according to an embodiment; FIG. 7 is a perspective view of a rotatable spray arm as shown in FIG. 6 with an inlet connection; FIG. 8 is a perspective cross-sectional view of a portion of the rotatable spray arm in FIG. 7; FIG. 9 is a cross-sectional view of the rotatable spray arm in FIG. 6; FIG. 10 is a bottom view of a surface member of the rotatable spray arm as shown in FIG. 6; FIG. 11 is a perspective view of a granule container; FIG. 12 is a perspective view of the granule valve; FIG. 13 is a perspective view of the granule container in FIG. 11 attached to a granule valve in FIG. 12; FIG. 14 is a cross-sectional view of a portion of the granule container as shown in FIG. 12 with a closed granule valve; FIG. 15 is a cross-sectional view of the granule container as shown in FIG. 12 with an open granule valve; FIG.16 is a perspective view of a tray for loading articles; and FIG. 17 is a flowchart of a dishwashing method.

Detailed Description Embodiments of the invention will be described with reference to FIGs. 1-17, which illustrate schematically an example arrangement to some embodiments. The same reference signs are used for corresponding features in different figures. The terminology used in the detailed description and drawings of the embodiments is not intended to be limiting.

The following description describes embodiments applicable to the field of dishwashing apparatuses for equipment surface treatment, such as dishwashers, including but not limited to dishwashers for small, medium, and large sized commercial kitchens, such as pot washers. The dishwashing apparatuses may be, but is not limited to, dishwashers for heavily soiled articles to be washed, for example dishwashers for pots and pans or other coarse articles to be washed. However, it will be appreciated that the disclosure is not limited to this application but may be applied to many other technical fields wherein a tray, basket or the like holding articles, including pots, pans, cauldrons, underwater equipment, such as a scuba diving equipment, working clothes, different kinds of tools or other industrial equipment etc, to be washed.

FIG.1 shows an embodiment of a dishwasher 100 for heavily soiled articles to be washed, for example pots, pans, ovenware, canteens etc., wherein the dishwasher may be arranged to add granules with liquid, including but not limited to water, or water and detergent, or any other suitable liquid for dishwashing that is sprayed under pressure towards the articles to be washed. In some embodiments the dishwasher may be arranged to circulate liquid alternatively with and without granules and/or with and without detergent. Thereby, the dishwashers may be used for washing more sensitive ware, such as crockery, cutlery and glasses, without the granules. The granules may be made of, but is not limited to, plastic material.

Referring to FIG. 1, the granule dishwasher 100 according to some embodiments comprises a stand 101, a dishwashing chamber 102, a washing tank 103a for washing liquid and a rinse tank 103b with a pump for rinsing liquid located below the dishwashing chamber and arranged on the stand, and a conduit system 104, comprising a washing liquid conduit system 104a and a rinse liquid conduit system 104b. The washing liquid conduit system connects the washing tanks 103a to the dishwashing chamber 102 and the rinse liquid conduit system connects the rinse tank 103b to the dishwashing chamber 102. A back wall 105 of the stand, a sink 106 and a hood 107 may form the chamber 102. The hood 107 is movably arranged to the back wall 105 of the stand. The hood 107 may be moved between a closed position as shown in FIG. 1 when the dishwasher is ready for operation, and an open position, in which dishes, preferably on a washing rack or ware holder, may be put into or removed from the chamber. The hood 107 may be moved by means of handles 108 arranged on the exterior of the hood.

Further, the dishwasher 100 comprises a liquid or water pump 109 arranged in the lower part of the stand 101, which can operate at different speeds, leading to different liquid pressures and flow of rinsing water or liquid and dishwater with an without granules through an upper rotatable spray arm 110 arranged in the upper part of the chamber 102 and a lower rotatable spray arm 111 arranged in the lower part inside the chamber 102 and connected to the washing liquid conduit system 104.

The pump of the rinse tank 103b may be configured to operate at different speeds, leading to different liquid pressures and flow of liquid through the upper rotatable spray arm 110 and the lower rotatable spray arm 111 being connected to the rinse liquid conduit system 104b.

The rinse liquid conduit system 104b may have a rinsing pipe 112 for providing rinsing liquid, i.e fresh water, circulation water, or any other suitable liquid, with or without rinsing agent, to the upper spray arm 110 and a separate dishwashing pipe 113 for providing dishwater to the upper spray arm 110. A corresponding arrangement with rinsing pipe and dishwashing pipe is provided for the lower spray arm 111. A low speed is used for washing up crockery, cutlery and glasses and a higher speed is used for pot washing. The speed of the liquid pump and the resulting liquid pressure should be adjusted to the specific dishwasher and the type of glassware or pots etc that are going to be washed up. Moreover, an electric cabinet 114 is arranged in the lower part of the stand 101 configured for main connection and power supply of the liquid pump 109, heaters in the washing tank and the rinse tank, the pump of the rinse tank, and a draining pump 115. The electric cabinet 114 may contain circuitry and/or a program-control device configured to run one or more different washing programs for operating the dishwasher in response to user input via a user interface, such as a control panel 116, arranged on and accessible from the exterior of the dishwasher and operatively connected to the circuitry.

The liquid pump 109 and draining pump 115 are connected to the washing tank 103 a through the washing liquid conduit system 104a. As mentioned above, the liquid pump 109 may be configured to operate at different speeds, leading to different water pressures and flows. A low speed is used for washing up crockery, cutlery and glasses and a higher speed is used for pot washing, with or without granules. The granules may be made of, but is not limited to, different plastic material preferably soft enough not to harm pans or the wash system, but hard enough to remove food from pots and pans. The lower part of the dishwasher may also comprise a removable granule container or basket 117, where the granules may be collected, separated from the liquid and removed from the dishwasher. This granule basket 117 may be provided with a granule valve 118 together forming a granule valve arrangement, for controlling the addition/collection of granules to/from the liquid in response to the washing program being run.

The speed of the liquid pump and the resulting liquid pressure through the spray arms 110, 111 may be adjusted to the specific machine and what type of glassware or pots that are going to be cleaned. The liquid pump 109 can also be driven by a standard electric motor, which is controlled by a speed regulator, such as a frequency changer or a variable-frequency drive. This gives more flexibility and several different speeds and liquid flows with and without granules can be provided.

FIG. 2 shows the rotatable spray arm 110, 111 according to an embodiment for a dishwashing apparatus as shown in FIG. 1. The upper and lower rotatable spray arms 110, 111 may have identical features and may be connected to the conduit system 104 in the same way and provide the same functional characteristics in operation. However, for the sake of simplicity only one of the rotatable spray arms 110, 111 will be described in detail herein. The spray arm 110 may comprise an elongated surface member 200 and an opposite elongated casing 202 on both sides of a center section 203. The elongated surface member 200 and the elongated casing 202 are assembled together, for example but not limited to a snap connection, forming an inside chamber of the spray arm 110 with number of channels for rinsing and dishwashing liquid. The elongated surface member 200 may be provided with a number of spray outlets, including spray jets or holes 204 for rinsing liquid, which are distributed along a first edge 205a of the surface member 200 on one side of the center section 203 and along a corresponding second edge 206a of the surface member 200 on the other side of the center section 203, which is illustrated in FIG 2. The elongated surface member 200 and casing 202 may be formed by, but not limited to, injection- molded plastic material.

The spray jets 204 are inclined at any angle a (FIG. 9) in the range of: 0< a <90, preferably but not limited to about 20°, in relation to the rotational axis Z (FIG. 1) of the spray arm when it is arranged in the dishwasher, from the inside chamber towards the edge along which the spray jets are disposed. Thereby, the spray arm 110 will be rotating in dependence on the amount and pressure of the rinsing liquid being pumped through the rinse liquid conduit system 104b into the spray arm 110 further through the spray jets 204.

The elongated surface member 200 may be provided with additional spray outlets, including a number of spray nozzles 212a-f for dishwashing liquid, three of which are distributed along a third edge 205b of the surface member 200 on one side of the center section 203 and the other three along a corresponding fourth edge 206b of the surface member 200 on the other side of the center section 203, which is illustrated in FIG 2. The spray nozzles 212a-f are disposed at any suitable angle ? in the range of: 0< ?<90, preferably but not limited to about 20° in relation to the length of the spray arm 110. In operation, dishwashing liquid flowing through the spray arm and out from the angled nozzles creates a force making the spray arm to rotate around its center section 203. Hence, the spray arm 110 will be rotating in dependence on the amount and pressure of the dishwashing liquid being pumped through the conduit system 104 into the spray arm 110 further through the dishwashing channels (described below) and the spray nozzles 212a-f.

As shown in FIG. 2, the spray nozzles 212a-c may be located at different individual distances from the center section than the spray nozzles 212d-f, thereby achieving good flow coverage, preferably overlapping, in the dishwashing chamber 104 for an improved dishwashing result.

FIG. 3 shows the rotatable spray arm 110 as shown in FIG. 1 with an inlet connection 203 a at the centre section 203 configured for rotatable connection to the conduit system 104, 104a, 104b. The connection 203a has a rinsing inlet 220 for guiding rinsing water into rinsing channels 230, 231 and a dishwater inlet 222 for guiding dishwater/liquid with or without granules into washing channels 232-234 and 235-237. Although, the rinsing inlet 220 and the dishwater inlet 222 are separate, the rinsing inlet 220 may have a filter 225 for preventing granules in the dishwater to pass into the rinsing channel of the spray arm 110, which otherwise may lead to clogged spray jets 204.

FIG. 4 illustrates the elongated casing 202 forming one part of the rotatable spray arm 110, which is provided with at least one rinsing channel 230, 231 in connection with the rinsing inlet 220 for rinsing water/liquid and the washing channels 232-234 and 235-237 in connection with the dishwater inlet 222 for dishwater/ dishwashing liquid with or without granules. In this embodiment, one rinsing channel 230, 231 is arranged on each side of the center section 203 providing an even distribution of rinsing water through the individual spray jets 204 in the surface 200, shown in FIG. 2. Individual washing channels 232-234 and 235-237 are provided on each side of the center section 203 in this embodiment, whereby almost the same pressure and flow of dishwater is provided in each spray nozzle 212a- f. In case of granules being used in the dishwater, they will be evenly distributed in the washing channels and the nozzles 212 a-f. In this embodiment the washing channels may have, but is not limited to, in cross section a shape corresponding substantially to a snip same side comer, snip comer, round same side comer, or round comer rectangle or similar shape. The geometry of the channels, i.e the shape in cross-section and in addition the relation between width and height of the channels, will produce an advantageous flow and prevent granule traps or clogging channels.

The spray arm is, however, not limited to one rinsing channel and three dishwashing channels on each side of the center section. The spray arm may have 1, 2, 3 or more rinsing channels and/or 2, 3, 4 or more individual washing channels on each side of the center connection in other embodiments of the spray arm.

FIG. 5 shows a locally enlarged view of end portions 242-244 of the washing channels 232-234. It should be understood that the features and advantages described herein with reference to the washing channels 232-234 are applicable to the other washing channels 235-237 and their end portions.

In this embodiment each end portion 242-244 has an inclined, curved or rounded shape 252-254, thereby guiding the dishwater with or without granules from the washing channels 232-234 towards the nozzles. Moreover, the shape of the channels may be narrowing from the center section 203 towards the nozzle, which may be provided by a continuous variation of the radius of the snip/rounded comers along the channels and the shape of the end portions may be narrowing or angled in line with the nozzles. Dishwater/liquid with and without granules are accelerated by means of the particular shape of the end portion, thereby causing self-cleaning of the channel due to “no dead end” and preventing clogging of granules and/or food particles at the end portion of the channel and the connecting nozzles 212a-f (as shown in FIG 2).

The shape of the end portions of the washing channels and the angled nozzles may even create a combined effect to increase the moving and rotational force by means of flowing dishwashing liquid for rotating the spray arm. Hence, the spray arm 110 will be rotating in dependence on the amount and pressure of the dishwashing liquid being pumped through the conduit system 104 into the spray arm 110 further through the dishwashing channels 232-237 and the spray nozzles 212a-f.

FIG. 6 is a perspective view of a portion of a rotatable spray arm 348 according to another embodiment for a dishwashing apparatus as shown in FIG. 1. The spray arm 348 may comprise an elongated surface member 300 and an opposite elongated casing 302 on both sides of a center section 303. The elongated surface member 300 and the elongated casing 302 are assembled together, for example but not limited to screw fastening 350, forming an inside chamber of the spray arm 348 with a number of channels for rinsing water/liquid and washing channels for dishwater/dishwashing liquid with or without granules. The elongated surface 300 may be provided with a number of spray jets or holes 304 for rinsing liquid, which are distributed along a first edge 305a of the surface member 300 on one side of the center section 303 and along an opposite second edge 306a of the surface member 300 on the other side of the center section 303, which is illustrated in FIG 6. The elongated surface member 300 and casing 302 may be formed by, but not limited to, injection- molded plastic material.

The elongated surface member 300 may be provided with a number of spray nozzles for dishwashing liquid, which are distributed on both sides of the center section 303. In this embodiment, three spray nozzles 312a-c are distributed along one side of the center section 303 and another three spray nozzles 312 d-f along the other side of the center section 303. In addition, still another nozzle 312g is arranged at the center section 303.

As shown in FIG. 6, the spray nozzles 312 a-g may be located at different individual distances from the center section, thereby achieving a distributed coverage in the dishwashing chamber 102 for an improved dishwashing result.

FIG. 7 shows the rotatable spray arm 348 as shown in FIG. 6 with an inlet connection 303 a at the centre section 303 configured for rotatable connection to the conduit system 104, 104a, 104b. The connection 303 a has a rinsing inlet 320 for guiding rinsing water into rinsing channels 330, 331 and a dishwater inlet 322 for guiding dishwater with or without granules into washing channels 332-334 and 335-337.

Although, the rinsing inlet 320 and the dishwater inlet 322 are separate, the rinsing inlet 320 may have a filter 325 for preventing granules in the dishwater to pass into the rinsing channel of the spray arm 348, which otherwise may lead to clogged spray jets 304.

Moreover, the shape of the channels may be narrowing from the center section towards the nozzle and shape of the end portions may be narrowing or angled in line with the nozzles. Dishwater with and without granules are accelerated by means of the particular shape of the end portion, thereby causing self-cleaning of the channel due to “no dead end” and preventing clogging of granules and/or food particles at the end portion of the channel and the connecting nozzles.

FIG. 8 shows an enlarged cross-sectional portion of the rotatable spray arm 348 in FIG. 7. In this embodiment the washing channels 336, 337 may have, but is not limited to, in cross section a shape corresponding substantially to a snip same side comer, snip comer, round same side comer, or round comer rectangle or similar shape. Preferably, all washing channels 332-337 may have the same shape in cross section. The shape and geometry of the channels will produce an advantageous flow and prevent granule traps or clogging of granules and/or food particles at the end portion channels.

In this embodiment, the rinsing channel 331 may have a rectangular shape in cross section. Moreover, the spray jets 304 are inclined at any angle ?, preferably but not limited to about 20° in relation to the rotational axis Z of the spray arm, i.e from the inside chamber towards the edge along which the spray jets are disposed. Thereby, the spray arm 348 will be rotating in dependence on the amount and pressure of the rinsing liquid being pumped through the conduit system 130 into the spray arm 348 further through the spray jets 304.

Reference is made to FIG. 9 which is an enlarged cross-sectional view of the spray arm in FIG. 6. The spray nozzles 312 (a-f) are disposed at any suitable angle in the range of: 0< ? < 90, preferably but not limited to about 20° in relation to the length of the spray arm 348. The angled nozzles create a moving and rotational force by means dishwashing liquid sprayed out from the nozzles as described above. In this embodiment, the spray nozzles 312 are projecting from the surface 300 as short pipe ends having cross sections in the shape of an elongated rectangle with convex long side walls 315, 316. The convex long side walls 315,316 are provided with an elongated concave cut-in portion 317 while two opposite short side walls 318,319 are rectangular as illustrated in FIG. 9. The side walls 315, 316, 318, 319 may have a curved top edge 327.

In another embodiment, the nozzles may have in cross section a shape corresponding substantially to an elongated rectangle of which the short sides of the rectangle are rounded or semicircular.

The particular shape of the nozzles described herein may provide an advantageous spray pattern from the nozzles and self cleaning of the nozzles making an improved dishwashing effect.

FIG. 10 shows a reverse side of the elongated surface member 300 forming an inner side of the spray arm 348, arranged with the rinsing spray jets 304 and holes 322ag connected to and angled in line with the dishwashing nozzles 312a-g as shown in FIG. 6. In this embodiment, the holes 322a-g may have, but is not limited to, in cross section a shape corresponding substantially to an elongated rectangle of which the short sides of the rectangle are rounded or semicircular.

An O-ring sealing 325 or similar sealing made of, but not limited to, rubber, is advantageously arranged around the rinsing channel(s) 330, 331 forming a water tight sealing for preventing leakage of rinsing liquid and dishwashing liquid with and without granules between the rinsing channel(s) 330, 331 and the dishwashing channels 332-337. The O-ring is preferably arranged in a recessed flange 326 on the inside of the surface member 330 forming a tight sealing between the surface member 300 and the casing 302 of the assembled spray arm 348, as shown in FIG 7.

The dishwasher may be provided with either an upper spray arm or a lower spray arm or both. The upper spray arm and the lower spray arm may be any combination of the embodiments of the spray arms 110, 111, 348, i.e two identical spray arms of the same embodiment or a combination of two different embodiments. In some embodiments, the dishwasher 100 is arranged to supply liquid to the upper spray arm 110 for washing, and liquid with or without granules to the lower spray arm 111 for washing. Both spray arms 110, 111 may be supplied with rinsing liquid during the rinsing phase of the washing program.

FIG. 11 shows an embodiment of the removable granule container or basket 117 in which granules may be collected and separated from the liquid. In this embodiment, the granule basket 117 may be a cylindrical basket, open in the top end 119 and perforated by recesses or holes 120 around the basket. The recesses or holes may be sufficiently wide to allow the passage of liquid but small enough to prevent the passage of granules. The granule basket 117, which is preferably made of any suitable metal or plastic material, may comprise a larger cylindrical upper portion 121 and a smaller cylindrical lower portion 122 assembled together. The larger cylindrical upper portion is both higher and has a larger diameter than the smaller cylindrical lower portion. In this embodiment, the basket is provided with two pins 123 (one shown in FIG. 11) projecting from opposite sides of the envelope surface of the smaller cylindrical lower portion 122. The basket may be provided with a handle 124 for easy removal of the granule basket 117 by hand from the dishwasher 100.

The granule valve 118, which is arranged in the dishwasher as shown in FIG. 1, is illustrated in further detail in FIG 12. In this embodiment the granule valve may comprise an upper perforated open ended cylindrical sleeve 125 arranged on a branch conduit 126, which may have a perforated filter plate or mesh 127 arranged on a top inlet of the conduit 126 or within the conduit. The perforations are large enough to let both liquid and granules to flow in to the branch conduit 126 but preventing food scraps and cutlery to limit or stop up the flow through the branch conduit. A pipe joint 128 is provided in the lower part of the branch conduit for connection to the conduit system 104, wherein the flow of liquid, with or without granules, may be drawn by means of the liquid pump 109 when the dishwasher is in an operating mode. Moreover, a draining pipe 129 is provided in the lower part of the branch conduit for connection to the draining pump 115.

The cylindrical sleeve 125 may have two L shaped recesses 130, 131 partly around portions of the cylindrical sleeve 125 for receiving the pins 123 of the granule basket 117 for connection of the granule valve 118 to the granule basket 117. The sleeve 125 may be assembled to the branch conduit 126 by means of a knurled nut 132 for easy disassembling/assembling in case of cleaning of the granule valve.

The granule valve 118 further comprises a valve push rod 133, which extends from the bottom of the branch conduit 126 through the filter plate 127 and the cylindrical sleeve 125. The valve push rod 133 is provided with a valve cone 134 at the top end thereof forming a valve plunger, which is arranged to open and close the granule valve arrangement, as will be described below.

As shown in FIG. 13 the granule basket 117 is removably arranged on the granule valve 118 forming a granule valve arrangement, wherein the pins 123 of the granule basket have been inserted in the corresponding recesses 130, 131 of the cylindrical sleeve 125 of the granule valve 118 by turning the granule basked until the pins 123 reach the end of the recesses 130, 131. A sensor 135, such as a magnetic or magneto-optical sensor, may be arranged in the washing tank 103 a in order to detect whether the granule basket is attached to the granule valve 118. The sensor 135 is operatively connected to the circuitry of the electrical cabinet 114 and configured to generate a sensor signal indicating whether the granule basket 117 is located and available for providing granules to the liquid depending on the washing program in operation.

FIG 14 illustrates a portion of the granule basket 117 attached to the granule valve 118 forming the granule valve arrangement. In this embodiment, a massive “puck” with a conical cavity is arranged as a valve head 136 on top of the valve cone 134. In a closed position as is shown in FIG 14, the valve head 136 rests on an edge 137, preferably chamfered, around an aperture 138 in a bottom end 139 of the upper portion 121 of the granule basket 117. The aperture 138 may preferably have a circular shape or any other suitable shape, such as oval or rectangular etc. The valve head 136 has a corresponding shape, and large enough to cover the aperture in a closed position. In some embodiments, the bottom end 139 may be perforated by recesses or holes 140 similar to the recesses or holes 120 in the envelope of the cylindrical granule basket 117. The recesses or holes 140 may be sufficiently wide to allow the passage of the liquid flow but small enough to prevent the passage of granules. A liquid flow through the recesses 140 may advantageously prevent granules from getting caught between the valve head 136 and the chamfered edge 137 when the granule valve 118 is moved to a closed position by a downward movement of the valve push rod 133.

FIG. 15 illustrates the granule valve arrangement including the granule basket 117 assembled with the granule valve 118 inserted in the dishwasher in an operative position. The removable granule basket 117 is inserted in the dishwasher, and arranged in a hole 119’ in the bottom of the sink 106, wherein the circular top end 119 of the granule basket is located at the same level as the bottom of the sink. The hole 119’ in the bottom of the sink and the circular top end 119 have corresponding diameters, so that granules cannot pass there between into the washing tank 103a. Preferably, the circular top end 119 may have a flange that may rest on the edge of the hole 119’, when the granule basket is inserted into the dishwasher.

In this embodiment, an upward movement of the valve push rod 133 is generated by a valve lifter arrangement comprising an electric motor 141, which is operatively connected to and controlled by the circuitry and the program control device of the electric cabinet 114. A hinged lever arrangement 142 that may be moved backward and forward (corresponding to a left direction and a right direction in FIG. ) is operatively connected and controlled by the electric motor 141. A backward movement of the hinged lever arrangement 142 causes an upward movement of the valve push rod 133, thereby moving the valve head 136 in to the position as shown in FIG. 15, i.e in an open position of the granule valve arrangement. A forward movement of the hinged lever arrangement 142 causes a downward movement of the valve push rod 133, thereby moving the valve head 136 in to a position as shown in FIG. 14, i.e the closed position of the granule valve arrangement. Thereby, an efficient and fast addition of granules is provided by a fast opening of the granule valve when granules are desired as well as an efficient collection of granules is provided by a fast closing of the granule valve when the granules are to be removed from the dishwashing apparatus.

FIG.16 shows an embodiment of a ware holder or tray 150 adapted for loading articles, such as pots and pans or other articles for coarse washing when the tray is inserted into a dishwasher, such as the dishwasher 100 in FIG. 1. The tray may have a rectangular frame 151 and transverse bars 152 . The frame 151 may have elongated cuts 153 along the sides of the frame 151 to keep pots and pans etc in position during a washing cycle. The bars may be bended in the bottom to keep pots and pans in position during washing. Few bars are provided to manage heavy pots and pans and at the same time avoid shadows from the wash spray which can influence the wash result. Magnets 154 may be provided at each side or comer of the frame 151. Corresponding sensors (not shown) are provided in the dishwasher and operatively connected to the circuitry of the electric cabinet for detecting the magnets of the tray, i.e indicating if the basket is in or out of the dishwasher. In response to the sensors detecting that the tray is located in the dishwasher, the washing program may add granules to the liquid during the dishwashing cycle.

As mentioned above, the dishwasher is configured to operate according to one or more different washing programs. Initially, the rinse tank is filled with liquid, which may be heated before it is sprayed into the washing chamber to fill up the washing tank with liquid, preferably via the spray arm. As described above, the liquid may include but is not limited to dishwater, or water and detergent, or any other suitable liquid for dishwashing, which is used for several dishwashing cycles before the liquid in the washing tank need to be exchanged.

FIG 17 is a flow chart illustrating a method for operating a dishwashing apparatus according to one embodiment. As described above, the electric cabinet 114 may contain circuitry and/or a program-control device configured to run one or more different washing programs for operating the dishwashing apparatus to run a washing cycle in response to user input via the user interface 116.

The method includes, but is not limited to, at least one washing cycle including dishwashing and rinsing. Before starting the dishwashing program a tray with articles to be washed may be inserted into the chamber 102 and the hood 107 is closed. A dishwashing program to initiate a washing cycle is started via the interface of the control panel 116. The rinse tank 103b may preferably be refilled by fresh water or other suitable rinsing liquid, which may be warmed up by a heater in the rinse tank for each washing cycle. The fresh liquid may be supplied from an external fresh water supply or another external liquid reservoir that may be connected to the rinse tank. The liquid may be supplied to the washing tank via the washing liquid conduit system and the spray arms or via a separate conduit in connection with the tank.

According to one embodiment, the liquid pump 109 is started at a low speed in an initial step, which leads to a low liquid pressure and flow. A detector or sensor arranged within the chamber as described above is activated for detecting what type of ware holder that has been placed in the chamber in step 401.

In response to that a ware holder or tray 150 adapted for pot-washing is detected in step 401 by means of sensors in the dishwasher detecting the magnets 154 on the tray, and that the granule basket 117 is detected by means of the sensor 135, the liquid pump 109 is controlled to provide high water pressure together with granules thorough the spray arms and spray nozzles as described above. Hence, the granules are added to the liquid in the dishwasher by controlling 402 the granule valve 118 to open after a few seconds, if desired and enabled by the current dishwashing program, for dishwashing with granules 403. Liquid with granules is pumped from the washing tank through the washing liquid conduit system and the spray arms on to the articles in the ware holder. Although, the liquid in the washing tank has been pre heated in the rinse tank, maintenance heating of the liquid may be provided by the heater in the washing tank for improved washing result. Before the end of a washing program with granules, the granule valve 118 is controlled 404 to close the valve. Although, the granules will be collected almost immediately in the granule basket 117, the dishwashing program continues for a short while, typically a few seconds to secure that all of the granules are collected. Then, the dishwashing program continues with rinsing 405 with liquid pumped from the rinse tank through the rinse liquid conduit system and the spray arms on to the articles in the tray. When the rinsing ends the dishwashing program may be finished, and the operator may open the hood 107 to remove the tray 150 with the clean dish.

However, if a ware holder for standard washing is provided, the granule valve 118 should be closed and the liquid pump 109 is controlled to provide low water pressure during dishwashing 406. The dishwashing program continues with rinsing 407 with liquid pumped from the rinse tank through the rinse liquid conduit system and the spray arms on to the articles in the tray. When the rinsing ends the dishwashing program may be finished, and the operator may open the hood 107 to remove the tray 150 with the clean dish.

Embodiments of the present invention have been described herein with reference to dishwashing programs. It will be understood that washing programs may be implemented in the form of an entirely hardware embodiment, or an embodiment combining software and hardware aspects including computer program instructions to control the dishwasher. These computer program instructions may be provided to a processor of the program-control device, a general purpose computer, special purpose computer, or other programmable data processing apparatus of the dishwasher to produce a machine, such that the instructions when executed create means for implementing the specified functions/acts of the washing programs to operate the dishwasher accordingly.

The features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention, which fall within the scope of the technology. For example, the dishwasher may be provided with either a single rotatable spray arm arranged in the upper part or in the lower part in other embodiments. Other configurations with one or more spray arms arranged within the chamber are possible within the scope of the present patent claims.

In addition, singular references do not exclude a plurality. The terms "a", "an", "first", "second" etc do not preclude a plurality. Reference signs in the claims are provided merely as a clarifying example and shall not be construed as limiting the scope of the claims in any way.

List of feature elements: granule dishwasher 100 stand 101 dishwashing chamber 102 washing tank 103 a rinse tank 103b conduit system 104 a washing liquid conduit system 104a a rinse liquid conduit system 104b back wall 105 sink 106 hood 107 handles 108 liquid pump 109 upper rotatable spray arm 110 lower rotatable spray arm 111 rinsing pipe 112 dishwashing pipe 113 electric cabinet 114 draining pump 115 control panel 116 granule container or basket 117 granule valve 118 top end 119 recesses or holes 120 larger cylindrical upper portion 121 smaller cylindrical lower portion 122 pin 123 handle 124 cylindrical sleeve 125 branch conduit 126 perforated filter plate 127 pipe joint 128 draining pipe 129 vertical recesses 130, 131 knurled nut 132 valve push rod 133 valve cone 134 sensor 135 valve head 136 chamfered edge 137 circular aperture 138 bottom end 139 recesses or holes 140 electric motor 141 hinged lever arrangement 142 tray 150 frame 151 transverse bars 152 elongated cuts 153 magnets 154 surface member 200 elongated casing 202 center section 203 spray jets or holes 204 first edge 205 a second edge 206a third edge 205b fourth edge 206b rinsing inlet 220 dishwater inlet 222 filter 225 rinsing channel 230, 231 washing channels 232-237 end portions 242-244 surface member 300 casing 302 centre section 303 an inlet connection 303a spray jets or holes 304 first edge 305 a second edge 306a spray nozzles 312a-f side walls 315, 316, 318, 319 rinsing inlet 320 dishwater inlet 322 O-ring sealing 325 recessed flange 326 top edge 327 rinsing channels 330, 331 washing channels 332-337 spray arm 348 screw fastening 350

Claims (16)

Claims

1. A rotatable spray arm (110, 111; 348) for a dishwashing apparatus (100), comprising an elongated surface member (200,300) and an elongated casing (202,302) on both sides of a center section (203,303), the surface member (200,300) and the casing (202,302) are assembled together forming an inside chamber of the spray arm (110,111; 348), wherein the inside chamber is divided in separate elongated washing channels (232-234, 235-237; 332-334, 335-337) provided on each side of the center section (203;303), said washing channels are connected to a dishwashing inlet (222;322) arranged to guide dishwashing liquid into the washing channels (232-234, 235-237; 332-334, 335-337) towards spray nozzles (212a-f;312a-g) at the end of each washing channel, characterized in that the spray nozzles (212a-f ; 312 a-g) are located at different individual distances from the center section (203,303).

2. The rotatable spray arm of claim 1, wherein end portions (242,243,244) of the separate washing channels have inclined, curved or rounded shape for guiding dishwashing liquid with or without granules at the end portions towards the nozzles (212a-f;312a-g).

3. The rotatable spray arm of claim 2, wherein the end portions (242,243,244) of the separate washing channels are narrowing.

4. The rotatable spray arm of any of the claims 1-3, wherein the washing channels (232-234, 235-237; 332-334, 335-337) have in cross section a shape corresponding substantially to any of a snip same side comer, snip comer, round same side comer, or round comer rectangle shape.

5. The rotatable spray arm of any of the claims 1-4, wherein the elongated surface member (200;300) is arranged with a number of spray nozzles (212a-f;312a-g) distributed along both sides of the center section (303), wherein the spray nozzles (212a-f;3 12a-g) are disposed at any angle in relation to the length of the spray arm (110, 111; 348).

6. The rotatable spray arm of claim 5, wherein the spray nozzles (212a-f ;312 a-g) are disposed at any suitable angle of about 20° in relation to the length of the spray arm (110;348).

7. The rotatable spray arm of any of the claims 1-6, wherein the spray nozzles (212a-f;312a-g) are projecting from the surface member (200,300), each nozzle having a cross section in the shape of an elongated rectangle with two opposite short sides and two opposite long sides, wherein two opposite short side walls (318,319) and two opposite long side walls (315,316), wherein each opposite long side walls (315,316) of each nozzle has an elongated concave cut-in portion (317), and the two opposite short side walls (318,319) are rectangular.

8. The rotatable spray arm of claim 7, wherein the long side walls (315, 316) of each spray nozzle (212a-f; 312a-g) are convex and the short side walls and the long side walls (315, 316, 318, 319) have a curved upper edge (320).

9. The rotatable spray arm of any of the claims 1-8, wherein the nozzles (212ae; 312a-f) have in cross section a shape corresponding substantially to an elongated rectangle of which the short sides of the rectangle are rounded or semicircular.

10. The rotatable spray arm of any of the claims 1-9, wherein the inside chamber of the spray arm (110,111,348) is provided with at least a rinsing channel (230, 23 1 ;330,331) in connection with a rinsing inlet (220;320) for guiding rinsing liquid into said at least one rinsing channel (230, 231 ;330,331) arranged on each side of the center section (203,303) for providing an even distribution of rinsing liquid through individual spray jets (204,304) in the elongated surface (200,300).

11. The rotatable spray arm of claim 10, wherein the spray jets (204,304) for rinsing liquid are distributed along a first edge (205a;305a) of the surface member (200,300) on one side of the center section (203;303) and along an opposite second edge (206a;306a) of the surface member (200;300) on the other side of the center section (203;303), wherein the spray jets (204;304) are inclined from the inside chamber towards the first edge (205a;305a) or second edge (206a;306a) along which the spray jets are distributed.

12. The rotatable spray arm of claim 11, wherein the spray jets (204) are inclined at any suitable angle (a) of about 20°, in relation to the rotational axis (Z) of the spray arm when it is arranged in the dishwasher.

13. The rotatable spray arm of any of the claims 1-12, wherein a watertight sealing (325) is arranged around the rinsing channel (330, 331) for preventing leakage of rinsing liquid and dishwashing liquid with or without granules between the rinsing channel (330, 331) and the dishwashing channels (332-337).

14. The rotatable spray arm of claim 13, wherein the watertight sealing (325) is an O-ring sealing arranged in a recessed flange (326) on the inside of the surface member (300) forming a tight sealing between the surface member (300) and the casing (302) of the assembled spray arm (348).

15. A dishwashing apparatus, comprising at least one rotatable spray arm (148,149:348) according to any of the claims 1-14.

16. The dishwashing apparatus of claim 15, wherein dishwashing apparatus is a granule dishwasher arranged to circulate liquid alternatively with and without granules.