EP2925206B1

EP2925206B1 - Automatic dishwashing machine having a rotary drum

Info

Publication number: EP2925206B1
Application number: EP13798300.3A
Authority: EP
Inventors: Giambattista BLASETTI
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-11-28
Filing date: 2013-11-25
Publication date: 2020-07-08
Anticipated expiration: 2033-11-25
Also published as: WO2014082972A1; ITAN20130221A1; CN104812284A; US20150289745A1; JP2015535455A; CN104812284B; EP2925206A1; JP6357166B2

Description

The present invention falls in the field of household appliances used to automatically wash dishes, cups, glasses and other kitchen tools. In particular, the present patent application for industrial invention relates to an automatic machine used to wash kitchenware, in particular coffee cups and more in particular one or more sets of coffee cups.
A dishwasher according to the prior art comprises a washing chamber that contains a drum that can be pulled out of said washing chamber to make loading easier, and reintroduced in the washing chamber before starting a washing cycle in the dishwasher.
The washing chamber is provided with nozzles that deliver water steam at settable pressure and temperature values, which intercepts the items disposed on the drum.
The dishwashers that are currently available on the market can be divided in two different types, according to the operation of the pull-out drum: according to a first type, said pull-out drum is a rotary drum, whereas according to a second type, said pull-out drum is a fixed drum.
Regardless of the type of drum, which can be either a rotary or a fixed drum, the dishwasher and/or relevant drum comprise means that ensure an easy introduction and extraction into and from the dishwasher.
With reference to dishwashers with rotary drum, when said dishwashers are in operating position, the drum rotates around its axis, perpendicular to the support surface of the drum. In such a case, the water is sprayed on the kitchenware items by means of fixed nozzles suitably disposed in such manner that the water jet coming out of these nozzles reaches and perfectly washes all the surfaces of the kitchenware items loaded in the rotary drum. Consequently, in addition to actuating a hydraulic pump in order to push the water towards the dispensers provided in the dishwasher, the electrical motor of said dishwashers activates a rotary motion of the drum that is rather slow in order to avoid breaking the kitchenware items contained in the drum.
In particular, with reference to the dishwashers with non-rotary pull-out drum, when said dishwashers make a washing cycle, the drum remains fixed inside the washing chamber. In such a case, the nozzles are disposed on rotary arms that are advantageously rotated by the water pressure. In order to provide a correct washing and rinsing of the items loaded inside the drum, the dishwashers comprise two series of nozzles, a first series of nozzles disposed above the support surface of the drum and a second series of nozzles disposed under the support surface of the drum. In view of the above, the cavity of hollow containers, such as cups, glasses, pots, etc. must be faced downwards in order to drain the water and prevent water stagnation.
However, it must be noted that, in addition to the main cavity, some types of glasses, normally defined as goblets, are provided with a concave base that, when facing upwards, originates a stagnation cavity for the fluids used during the washing cycle. The same drawback impairs the majority of mugs and cups that are provided with a lower base from which an annular support element protrudes, which stops the fluids that reach said lower base, causing undesired water stagnation.
Moreover, it must be noted that the dishwashers that are currently available on the market are designed in such manner to house any type of kitchen tools, including large items, such as pots, lids and serving dishes. In other words, the washing chamber must have a suitable height in order to house items that are much bigger than mugs, cups and glasses. In view of the above, when large items are not present, it is practically impossible to use the entire volume of the washing chamber of a traditional dishwasher, which can be advantageously used only after cooking activities. In other words, the structural configuration of the currently available dishwashers impairs the use of the dishwashers for a limited number of glasses and/or mugs and cups.
FR926315 discloses a rotary drum inserted in a truncated-conical washing chamber with tilted bottom wall and nozzles disposed above the rotary drum in such manner to spray according to a vertical or radial direction with respect to the axis of rotation of the drum. The drum has a cage-shaped structure with circular and longitudinal sections.
FR480252 discloses a dishwasher with fixed drum inserted in a cylindrical chamber and nozzles disposed under the fixed drum.
None of the prior documents discloses a system used to detect the position of the drum in order to avoid that the kitchenware items remain full of water.
The main purpose of the present invention is to remedy the aforementioned drawback by devising a method to use a dishwasher that, with a single series of nozzles, makes a complete washing of any item loaded in the drum and guarantees the elimination of unpleasant stagnation regardless of the geometrical shape of the items loaded in the drum.
Another purpose of the present invention is to devise method to use a dishwasher that, in addition to satisfying the aforementioned purposes, the dishwasher has a drum provided with such a structural configuration that allows using the space at best in the presence of small items, such as cups, mugs, glasses, goblets, saucers and plates.
The automatic machine of the method of the invention, which is used to wash kitchenware, comprises a rigid support frame, one or more covering panels fixed to said rigid support frame and a compartment defined by said covering panels.
Moreover, the automatic machine of the method of invention comprises a washing chamber that is disposed inside said compartment and houses a rotary drum.
Specifically, said washing chamber has a bottom wall that is tilted by an angle higher than 3° with respect to the horizontal axis.
Finally, the automatic machine comprises at least one nozzle, the dispenser point of which is disposed inside the washing chamber.
The machine comprises:

an encoder to count the number of revolutions of the rotary drum,
a control unit adapted to compare the number of revolutions counted by the encoder with a preset number of revolutions,
a stop device (B) that temporarily stops the rotation of the drum, when the number of revolutions detected by the encoder is equal to the preset number of revolutions minus half a revolution, in such manner that the kitchenware items are situated above the axis of rotation of the drum to drain water;
a timer that temporarily stops the rotation of the drum for a preset time interval and successively releases the rotation of the drum to make the last half revolution, complete the washing cycle and bring the kitchenware items back to the loading position.

Because of the provision of such components, the automatic machine guarantees the elimination of unpleasant stagnation inside the cavity of the kitchenware items loaded in the drum at the end of the washing cycle.
In fact, the encoder counts the number of revolutions made by the dishwasher and the control unit compares such a number of revolutions with a preset number of revolutions equal to the complete washing cycle.
If the kitchenware items are loaded with cavity facing upwards, when the control unit detects that the number of revolutions counted by the encoder is equal to the preset number of revolutions minus half a revolution, it actuates the stop device so that the kitchenware items are stopped for a few seconds with the cavity facing downwards and water can be drained from said cavity.
Therefore, the last revolution of the rotary drum is completed after a preset time interval, during which the cavity of the kitchenware items faces downwards and any residual liquid deposited in such a cavity is drained.
For explanatory reasons, the description of the method to use an automatic machine according to the present invention continues with reference to the attached drawings, which only have illustrative, not limiting value, wherein:

Fig. 1 is an axonometric view of the automatic machine of the method of invention without covering panels;
Fig. 2 is a side view of the automatic machine of the invention of Fig. 1 without covering panels;
Fig. 3 is an axonometric view of the rotary drum of the automatic machine without kitchenware items;
Fig. 4 is an axonometric view of the rotary drum of Fig. 3 with kitchenware items;
Fig. 5 is an axonometric view of the rotary drum of Fig. 3 with a cup supported by lock means;
Fig. 6 is a diagrammatic, partially interrupted axial sectional view of the automatic machine and
Fig. 7 is a block diagram showing the operation of the automatic machine.

Referring to Figure 1, the automatic machine is generally indicated with reference numeral (1).
The automatic machine (1) shown in Figs. 1 and 2 is represented without the lateral covering panels and the upper panel in order to show all the parts contained in the machine.
In any case, said automatic machine (1) comprises a rigid frame (2) that supports a series of covering panels, not shown in the attached figures, of which a front panel, a back panel, an upper panel, a bottom panel and a pair of lateral panels.
Said covering panels define a compartment (V) adapted to house the parts of the machine.
The automatic machine (1) comprises a washing chamber (3), a clean water tank (4), a boiler (5) (Fig. 2) and a drain tank (6) disposed in said compartment (V).
Referring to Fig. 2, the washing chamber (3) advantageously has a truncated-conical shape. Said washing chamber (3) has a bottom wall (32) that is tilted by an angle (α) higher than 3° with respect to the horizontal axis. Advantageously, the angle (α) is 5°.
It must be noted that the horizontal direction is parallel to the support surface of the automatic machine of the invention.
According to an embodiment not shown in the attached figures, the automatic machine of the invention is provided with a cylindrical washing chamber.
Referring to Fig. 1, the washing chamber (3) houses a rotary drum (7) in coaxial position to the washing chamber, and a series of nozzles (8) disposed under the rotary drum (7) and from which steam jets are ejected during a washing cycle of the automatic machine (1).
Moreover, the washing chamber (3) comprises a door (31) provided on the front panel of the automatic machine (1) that can be opened to access the rotary drum (7).
Referring to Fig. 2, the rotary drum (7) is provided with a basically horizontal axis of rotation (Y).
It must be noted that, if the washing chamber (3) has a cylindrical shape, the axis of rotation (Y) of the rotary drum (7) is advantageously tilted with respect to the horizontal axis in order to favor the outflow of the dirty water possibly deposited inside the washing chamber (3) because the washing chamber is coaxial with respect to the drum.
Vice versa, if the washing chamber (3) has a truncated-conical shape, as shown in the enclosed figures, it is not necessary to tilt the axis of rotation (Y) of the rotary drum (7), because the truncated-conical shape guarantees water draining because of the inclination of the bottom wall (32) of the washing chamber.
The nozzles (8) are preferably disposed in such manner to spray steam according to a vertical direction and/or according to a radial direction with respect to said axis of rotation (Y) of the drum.
Referring to Fig. 3, the rotary drum (7) comprises a cage made of a plurality of circular sections (70) bent in such manner to form a plurality of consecutive circles, having the same diameter and disposed in parallel position, and a plurality of straight longitudinal sections (71) that cross the circular sections (70).
The rotary drum (7) is provided with a bottom portion that comprises one or more circular sections with lower diameter (72) with respect to said circular sections (70) and a plurality of radial sections (73) that connect the circular section (70) with higher diameter with the circular sections with lower diameter (72).
According to an alternative embodiment not shown in the attached figures, said rotary drum (7) can be made of sheet steel provided with a plurality of holes to allow the fluid coming out of the nozzles to achieve the kitchenware items loaded inside the rotary drum.
The rotary drum (7) is connected to a drive shaft (90) of an electrical gear motor (9) provided inside the automatic machine (1) so that said rotary drum (7) is driven into rotation as soon as the electrical gear motor (9) is actuated.
Specifically, the electrical gear motor (9) is supported by the rigid frame (2) of the automatic machine (1) and the drive shaft (90) of said gear motor (9) supports the rotary drum (7) and protrudes into the washing chamber (3). More precisely, the drive shaft (90) passes through the washing chamber (3) and is coupled with the bottom portion of the rotary drum (7).
Referring to Fig. 5, the bottom portion of the rotary drum (7) is inserted on the drive shaft (90) of said electrical gear motor (9) with movable prismatic coupling, so that the rotary drum (7) is advantageously introduced or extracted from the washing chamber (3) to load the kitchenware items or carry out maintenance operations on the parts of the automatic machine according to the invention.
According to an alternative embodiment of the automatic machine of the invention not shown in the attached figures, said rotary drum (7) can be loaded from the top by means of three openings respectively obtained on the upper panel of the automatic machine, on the washing chamber (3) and on the rotary drum (7). The openings are manually opened by the user when the machine is stopped.
Referring to Fig. 4, the rotary drum (7) houses a set of tableware items (11, 12, 13), comprising a saucer (11), a coffee cup (12) and a teaspoon (13). Specifically, the coffee cup (12) is advantageously positioned inside the rotary drum (7) with the cavity facing upwards in order to prevent any liquids contained inside it from dripping.
The rotary drum (7) is provided with locking means (74) adapted to prevent the movement of the kitchenware items (11, 12, 13) loaded inside said rotary drum (7) during rotation. Specifically, the locking means (74) consist in inserts (74) advantageously made of stainless steel or thermoformed materials with high temperature resistance properties. In particular, the inserts (74) comprise flexible rods (74) with two ends (74a, 74b), each of them being joined with said circular sections (70) or said straight longitudinal sections (71).
Referring to Fig. 4, the surface of each kitchenware item (11, 12, 13) loaded inside the rotary drum (7) is in contact with the corresponding insert (74) in specific support positions (P) of the insert. It must be noted that each insert (74) is slightly elastic in order to allow for and favor the positioning of the kitchenware items. In this way, each insert (74) is deformed in the support positions (P) and adapted to the configuration of the kitchenware item (11, 12, 13) while holding it in fixed position during a washing cycle.
Each insert (74) is made in such manner to minimize the number of support positions (P) with the kitchenware item (11, 12, 13) in order to guarantee the complete washing of the item during each washing cycle of the automatic machine (1).
Referring to Figs. 6 and 7, according to the invention, the electrical gear motor (9) comprises an encoder (E) that counts the number of revolutions (N) of the drive shaft (90) and therefore the number of revolutions of the drum (7) connected to the drive shaft (90). The encoder (E) is connected to a control unit (CPU) that controls a stop device (B) adapted to stop the rotation of the gear motor (9). The automatic machine also comprises a timer (T) connected to the control unit (CPU) to release the stop device (B).
Optionally, the automatic machine comprises detection means (R), such as for example a position sensor, to detect the position of a kitchenware item (12) in the drum (7). In particular, the detection means (R) detect whether the item (12) has an upward cavity. The detection means (R) are fixed to the washing chamber (3) and electrically connected to the control unit (CPU).
In order to better understand the operation of the automatic machine of the invention, the description continues with reference to a washing cycle.
The kitchenware items (11, 12, 13) are manually loaded by the user inside the rotary drum (7) through the opening of the door (31) of the washing chamber (3) and disposed inside said rotary drum (7) in such manner that all surfaces of said items (11, 12, 13) are reached by the washing fluids coming out of the nozzles (8).
After positioning the items (11, 12, 13) inside the rotary drum (7), the user starts a washing cycle of the automatic machine (1) by pressing a button, after closing the door (31) of the washing chamber (3).
During the washing cycle, the rotary drum (7), which is connected to the electrical gear motor (9), rotates for a preset number of revolutions around its axis of rotation (Y) and the items (11, 12, 13) are reached by high-temperature steam jets coming out of the nozzles (8). Specifically, the clean water tank (4) housed in the compartment (V) of the automatic machine (1) contains clean water that is previously heated by the boiler (5) and converted into steam that comes out of each nozzle (8).
Specifically referring to Fig. 2, each nozzle (8) is provided with a dispenser point (81) and disposed under the axis of rotation (Y) of the rotary drum (7) in such manner that the dispenser point (81) protrudes inside the washing chamber (3) for a height higher than the maximum level of the dirty water that can be temporarily deposited inside the washing chamber during a washing cycle. In view of the above, the steam jets coming out of the dispenser point (81) of each nozzle (8) do not reach the dirty fluid.
At the end of the washing cycle, the steam returns to the liquid state and is conveyed in the drain tank (6), preferably provided with a filter to prevent the passage of undesired solid elements.
At the end of the washing cycle, the kitchenware items (11, 12, 13), and in particular the cups (12) loaded inside the rotary drum (7) must be with cavity facing downwards, preventing water from stagnating inside it.
The machine provides for loading the kitchenware items with their cavity facing upwards and stopping the washing cycle when the kitchenware items are disposed above the axis of rotation (Y) of the rotary drum (7), i.e. with the cavity facing downwards in such manner to drain water from the cavity of the kitchenware items. Then the machine makes a repositioning cycle by rotating the drum by half a revolution in order to bring the kitchenware items back to the loading position. When the kitchenware items are in the loading position, the door (31) of the washing chamber can be opened to take out the items.
Therefore, the operation cycle of the automatic machine of the invention comprises a washing cycle and a repositioning cycle in which the drum makes half a revolution.
To that purpose, the rotation of the rotary drum (7) is controlled by means of the encoder (E) and the control unit (CPU). From the start of the automatic machine (1), the encoder (E) counts the number of revolutions (N) made by the rotary drum (7) and the control unit (CPU) compares the number of revolutions (N) counted by the encoder with a preset number of revolutions (Np).
When the number of revolutions (N) counted by the encoder is equal to the preset number of revolutions (Np) minus half a revolution (N = Np - ½) the washing cycle ends and the control unit (CPU) sends a control signal (S1) to the stop device (B) that stops the rotation of the gear motor (9). Simultaneously, the control unit (CPU) sends a control signal (S2) to the timer (T) that starts counting a preset time interval, for example a pause of 2 - 4 seconds, in order to drain the liquid from the cavity of the kitchenware items. When the preset time interval has elapsed, the timer (T) sends a control signal (S3) to the stop device (B) in order to release the gear motor (9) and start the repositioning cycle, in which the drum (7) makes the last half a revolution to return to the loading position.
Although the structure of the drum implies that the cups are positioned with the cavity facing upwards, the user might erroneously load the cups with the cavity facing downwards. In such a case the repositioning cycle would not be necessary. To that end, the detection means (R) are optionally actuated.
When the detection means (R) detect that the kitchenware items (12) are not positioned correctly, i.e. are positioned with the cavity facing downwards, the control unit does not make the repositioning cycle and the washing cycle directly ends with the drum in the loading position.
The provision of the detection means (R) allows for eliminating the temporary interruption of the washing cycle when the cups are loaded with the cavity facing downwards in the drum because in such a case it is not necessary to drain the water from the cavity of the cups. However the detection means (R) can be optional.
An alternative embodiment of the automatic machine (1) of the invention, not shown in the attached figures, provides for a fixed drum and a series of rotary nozzles.
In such a case, the kitchenware items will maintain the loading position during the entire washing cycle and, consequently, must be suitably positioned in the drum in order to avoid the accumulation of dirty water.

Claims

A method to use an automatic machine (1) to wash kitchenware items (11, 12, 13);
the automatic machine (1) comprising:
- a rigid support frame (2),

- one or more covering panels fixed to said rigid support frame (2),

- a compartment (V) defined by said covering panels,

- a washing chamber (3) disposed inside said compartment (V) and provided with a bottom wall (32) tilted with respect to the horizontal axis by an angle (α) higher than 3° in order to make the washing water flow towards an outlet,

- a rotary drum (7) disposed inside the washing chamber (3) and provided with axis of rotation (Y),

- at least one nozzle (8) provided with at least one dispenser point (81) disposed inside said washing chamber (3),

- an encoder (E) to count the number of revolutions (N) of the rotary drum (7),

- a control unit (CPU) connected to the encoder and adapted to compare the number of revolutions (N) detected by the encoder with a preset number of revolutions (Np),

- a stop device (B) connected to the control unit (CPU) and encoder (E), said stop device (B) being configured to stop,

- a timer (T) connected to the control unit (CPU) and stop device (B), said timer (T) counting for a preset time interval and being configuration to control the stop device (B),
the method comprises the following steps:
- load the kitchenware items (11, 12, 13) into the drum, in loading position wherein the kitchenware are situated under said axis of rotation (Y);

- start the rotation of the drum wherein the encoder (E) counts the number of revolutions (N) of the rotary drum (7) and the control unit (CPU) compares the number of revolutions (N) detected by the encoder with the preset number of revolutions (Np),

- stop the rotation of the drum, my means of the stop device (B), when the number of revolutions (N) detected by the encoder is equal to the preset number of revolutions (Np) minus half a revolution (N = Np - ½), in such manner that the kitchenware items (11, 12, 13) are situated above the axis of rotation (Y) of the drum to drain water,

- count the preset time interval, by means of the timer (T),

- release the rotation of the drum, after the preset time interval, to make a last half revolution of the drum and bring the kitchenware items back to the loading position.
The method of claim 1, wherein said encoder (E) is installed in a gear motor (9) provided with a drive shaft (90) connected to said drum and said encoder (E) counts the number of revolutions (N) of said drive shaft (90).
The method of claim 1 or 2, wherein said timer (T) is adapted to temporarily stop the rotation of the drum for a preset time interval comprised between 2 and 4 seconds.
The method of any one of the preceding claims, wherein the automatic machine (1) also comprises detection means (R) to detect the position of the kitchenware items (12) in the rotary drum, said detection means (R) being operatively connected to the control unit (CPU) to monitor the washing cycle in accordance to the position of the kitchenware items.
The method of claim 4, wherein said detection means (R) comprise a position sensor fitted to the washing chamber (3) to detect the direction of the cavity of the kitchenware items.
The method of any one of the preceding claims, wherein said angle (α) between the base wall (32) of the washing chamber and the horizontal axis is 5°.
The method of any one of the preceding claims, wherein said washing chamber (3) has a truncated-conical shape.
The method of any one of claims 1 to 6, wherein said washing chamber (3) has a cylindrical shape and said axis of rotation (Y) of the rotary drum (7) is inclined with respect to the horizontal axis.
The method of one of the preceding claims, wherein said at least one nozzle (8) is disposed in such manner to spray steam according to a vertical direction or a radial direction with respect to the axis of rotation (Y) of the rotary drum (7).
The method of the preceding claim, wherein said at least one nozzle (8) is disposed under the axis of rotation (Y) of said rotary drum (7).
The method of one of the preceding claims, wherein said rotary drum (7) comprises a cage made of a plurality of circular sections (70) bent in such manner to form a plurality of consecutive circles, disposed in parallel position, and a plurality of straight longitudinal sections (71) that cross the circular sections (70).
The method of the preceding claim, wherein said rotary drum (7) is provided with a bottom portion comprising one or more circular sections with lower diameter (72) with respect to said circular sections (70) and a plurality of radial sections (73) connecting the circular section (70) with higher diameter with circular sections with lower diameter (72).
The method of one of the preceding claims, wherein said rotary drum (7) is provided with locking means (74) adapted to prevent the movement of the kitchenware items (11, 12, 13) loaded inside said rotary drum (7) during rotation.
The method of the preceding claim, wherein said locking means (74) consists in inserts (74) that comprise flexible rods (74) with two ends (74a, 74b), each of them being joined with said circular sections (70) or said straight longitudinal sections (71).