EP2384683B1 - Dishwasher with at least one spray arm - Google Patents

Description

The invention relates to a dishwasher, in particular domestic dishwasher, with a washing container for loading introduced items, especially crockery, cutlery and / or other cooking utensils, with a circulating liquid, said liquid is introduced via at least one rotatable spray arm in the washing and its rotation frequency can be measured by a magnetic detection, according to the preamble of claim 1.

DE4020898 discloses a dishwasher according to the preamble of claim 1.

In practice, in some dishwashers on the spray arms individual permanent bar magnets applied to fixed spatial positions, thereby controlling the rotational movement of the respective spray arm via a non-contact sensors, for example via a Hall sensor, and about a blockage of the spray arm on too high projecting To be able to detect parts of the items to be washed.

However, such a construction is expensive manufacturing technology, since on the one hand in the respective spray arm receiving troughs for the magnets must be embedded, including for injection molded parts additional moldings must be provided to effect the formation of these receiving troughs. Also, the permanent determination of the permanent magnets requires additional time and assembly costs. In addition, the bar magnets are relatively heavy and increase due to their far outside the spray arm mounting its moment of inertia significantly, which is undesirable in rotating parts.

The invention is based on the problem of achieving an improvement here.

The invention solves this problem by a dishwasher, in particular household dishwasher, with the features of claim 1. Further advantages and features and further developments of the invention are specified in claims 2 to 12.

By the invention it is achieved that directly with the production of the respective spray arm and its magnetic properties can be manufactured and adjusted.

An attachment of other parts of the spray arm is completely unnecessary for this purpose. As a result, impairments in the design and training of the respective spray arm, as would be the case with individual, provided at fixed spatial positions of the spray arm bar magnet avoided. Thus, it is no longer necessary to apply a certain portion of the spray arm, such as e.g. to reserve its outer end portion for the assembly with a bar magnet. Therefore, now the geometry shape and the formation of the hydraulic elements of the respective spray arm, which serve the guidance and distribution of rinsing liquid, such as. the outlet openings, in particular spray nozzles of the spray arm, and / or the course and the length of the one or more fluid channels in the interior of the respective, according to the invention designed spray arm are freely selected. In particular, one or more outlet openings, preferably spray nozzles, expediently upper side, lower side, and / or front side, without limiting the mounting location can be provided, for example, at the outer end portion of the respective Sprüharms, as would otherwise be the case for stationary, singular or individual bar magnet. The spray arm designed in accordance with the invention can thus be designed to be free on the entire length of its two half-arms without regard to pre-assignment positions for singular bar magnets. In particular, it is possible to extend or extend one or more inflow channels in the interior of the two half arms of the respective spray arm up to their free ends. Overall considered by the elimination of a fixed end provided, separate or singular bar magnet results in a much greater latitude in the design and the design of each Sprüharms in terms of its hydraulic properties.

In addition, the production of the spray arm designed according to the invention is shortened and simplified; In addition, in the magnetizable plastics anyway only a slight increase in weight compared to non-magnetized plastics recorded, and the additional weight can be evenly distributed, without concentration in radially far outlying areas. The moment of inertia is thereby only minimally increased.

The spray arm can therefore also form a light and easy-to-manufacture one-piece or multi-piece injection molded part with the incorporated magnetisable portions, whereby metal parts are embedded only in the plastic matrix.

These magnetizable parts of the spray arm may preferably be exposed during the injection molding of the spray arm by means of an injection molding or in a subsequent production line at least one external magnetic field for aligning metal parts and / or for entering a preferred direction of magnetization so as to produce permanently aligned permanent magnets, which in later Operation without contact with an external sensor, such as a reed switch, can cooperate.

The orientation of the metal parts via an external magnetic field can be carried out favorably in a phase in which the plastic of the spray arm is still softened.

If individual wings of the at least one spray arm are magnetized differently, during operation it can also be detected which end of the respective spray arm is moved past the sensor.

Conveniently, the or each spray arm over its entire longitudinal extent comprise at least one area of a magnetizable plastic material, in particular of a magnetizable, based on a plastic matrix material, so that the additional mass is radially evenly distributed by the magnetizable areas.

Manufacturing technology, it is advantageous if the or each spray arm comprises an upper and a lower shell, which are connected to each other at the edge via bordering profile frame and the profile frame are formed from magnetizable plastic. The actual shells of the spray arm can then remain unchanged from the non-magnetized version. It is also easy to retrofit or retrofit.

Further advantages and features will become apparent from the drawing illustrated and described below embodiments of the subject invention.

Fig. 1

eine beispielhafte Geschirrspülmaschine mit zwei Sprüharmen in einer möglichen erfindungsgemäßen Ausbildung in einer schematischen Seitenansicht,

Fig. 2

eine teilweise geschnittene Detailansicht eines Sprüharms, dessen seitliche Profilrahmen magnetisiert sind.

In the drawing shows:

Fig. 1

an exemplary dishwasher with two spray arms in a possible embodiment of the invention in a schematic side view,

Fig. 2

a partially sectioned detail of a spray arm, the side profile frame are magnetized.

Elements with the same function and mode of operation are each provided with the same reference numerals in the figures.

In the FIG. 1 only schematically illustrated dishwasher 1 is designed as a household dishwasher. It comprises a washing container 2 for items to be cleaned, for example dishes or cutlery, glasses, pots and similar cooking utensils. As shown FIG. 1 is the rinse tank 2 closed by a front door 3. The closed door position is in the schematic side view of the dishwasher after FIG. 1 shown.

The ware is in the washing container 2 via at least one, here two spray arms 4, 5 with circulating liquid S, in particular water, which may be mixed with cleaning substances or auxiliary substances, such as rinse aid, various types, acted upon. The two spray arms are provided here to act on an upper dish rack 6 and a lower dish rack 7 with circulating liquid S, so-called. Flushing liquor. Also, a different number of baskets is of course possible. In the crockery baskets 6, 7 each wash items can be held and acted on here two spray arms 4, 5 with wash liquor S, each with an upward component. For smaller dishwashers 1, often only one spray arm 4 or 5 is present.

The drawn dishwasher 1 further comprises a supply device for fresh water FW, can be introduced via the externally supplied fresh water FW in the washing compartment 2. Due to its gravity, the water from the rinsing container 2 collects as a rinsing liquor S in a collecting pot 10, which in the lower part of the rinsing container 2 is referred to as a depression in its bottom, which is also referred to as a rinsing pan 16 is located. Here can also be a total designated 17 screening device.

The collecting pot 10 is followed by a circulating pump 11, with the aid of which the rinsing liquor S can be pumped during a circulation phase of a rinsing from the collecting pot 10 via a heater 12 to a distribution space 13 for re-introduction into the spray arms 4, 5. The spray arms are here rotatable about a common vertical axis 8, wherein the rotational speed and also the respectively introduced amount of wash liquor S between the spray arms 4, 5 may differ depending on the program phase.

In order to be able to dissipate rinse liquor S that is no longer needed from the rinsing container 2, a suds pump 14 is furthermore provided, which is connected on the suction side to the collection pot 10 and on the output side to a waste water connection line 15. By means of the drain pump 14, it is possible to pump out wash liquor S during a pumping down phase of a wash cycle as wastewater AW to the outside.

In order to ensure proper program flow, the rotational frequency of at least one of the two spray arms 4, 5 - here both spray arms 4, 5 - measured by a magnetic detection contact. Thus, in particular, of course, a blockage of the respective spray arm 4, 5 such. can be detected by upright crockery parts. But also a delay of the movement by, for example, a slower grinding of items to be washed or too fast turning by too high a pressure of ejected at spray nozzles 9 wash liquor S can be detected.

In order to be able to perform this rotational frequency detection, the respective spray arm 4, 5 to be measured is formed at least partially from a magnetizable material based on a plastic matrix.

The respective spray arm 4, 5 can form a lightweight and easy-to-manufacture single-part or multi-piece injection-molded part, wherein embedded in the injection molding material in the plastic matrix metal particles, for example of a ferromagnetic material, are included. Such an injection-molded part can be formed in a single mechanical step, without the need for a mechanical post-processing, such as the application of separate metal components. In addition, the small remain Weight of a plastic assembly and also their resistance to corrosion. Overall, the manufacturing costs and the time required compared to a solution with separately applied magnets are significantly reduced.

Already during the injection molding of the spray arm 4, 5 or in the subsequent production line, the formed component can be exposed to at least one externally applied magnetic field for aligning the metal parts contained contactlessly and also in a continuous process without delaying production, thereby producing a permanent magnet. In particular, the magnetization can take place in a phase in which the plastic matrix is still softened, for example by the action of high temperature. Subsequently, the achieved alignment of the metal parts can then be frozen when cooling the plastic.

The magnetization can take place similarly over the entire radial extension of the spray arm 4, 5. But it is also possible, for example, that in a two-winged spray arm, the two wings are magnetized differently, so as to distinguish in the measurement, which is the wing or half arms just detected, for example, characterized in that only one wing is magnetized and the others not. Alternatively, wings with mutually different orientations of the metal particles can be magnetized, for example, one wing in the radial and the other wing in axial alignment of the particles.

For this detection, for example, a reed switch or a Hall sensor is provided as the detecting sensor 18, which can be assigned to the washing container 2 stationary. Reed switches have two facing ferrous metal lips which, in response to an applied magnetic field, pull against the force of a spring to establish electrical contact. Hall sensors are based on the effect that in a magnetic field moving charge carriers are deflected. They provide a signal that is proportional to the strength of the applied magnetic field. Both sensors therefore give a signal when approaching a permanent magnet - such as here a magnetized spray arm - whereby the approach of a wing to the sensor 18 is detectable. The data thus obtained for the movement of the spray arm or the spray arms 4, 5 can be evaluated in a computing unit in order to signal disturbances and if necessary to be able to initiate a stop of the program or other measures.

In order to be able to achieve such selective magnetizations, as described above, in the production device of the spray arms 4, 5 individual wings or their sub-areas (for example, frame profiles 19 described in more detail below) in cross-magnetization devices can be introduced, that is, the wings briefly be overlapped by hood-like outer bodies (in particular electromagnets) without contact and thereby exposed in these bodies acting magnetic fields, so that align the metal particles and the spray arm 4, 5 itself or a permanent magnet itself.

In this case, it is easy to manufacture if the or each spray arm 4, 5 comprises over its entire longitudinal extent at least one uniform region 19 of a magnetizable, based on a plastic matrix material. For example, this area can be Fig. 2 ) may be formed from radially extending edge profiles 19 of the spray arms 4, 5, wherein via the edge profiles 19, an upper and a lower shell 20, 21 of the respective spray arm 4, 5 may be interconnected. The shells 20, 21 are curved so convex that between you a radially extending cavity 22 is formed, passed through the wash liquor S and then through the nozzles 9, the in FIG. 1 are indicated only on one side of the lower spray arm 5, can be deployed. The nozzles are preferably provided on the upper side in the upper shell of the respective spray arm. Additionally or independently thereof, however, they can also be provided on the underside on the lower shell of the respective spray arm. This can be favorable in particular in the case of the upper spray arm, since then the items to be washed in the lower dish rack can be sprayed from above in addition to the spraying jets of the lower spray arm directed from the bottom upwards through the upper spray arm.

The profile frame 19 are themselves plastic-based and can thus also by injection molding with the shells 20, 21 are co-extruded or subsequently molded onto this. The shells 20, 21 can also be made of plastic cheap; however, this is not mandatory. Also, for example, a metallic training is possible in principle. The coextrudability of shells 20, 21 and profile frame 19, however, is very low in terms of production technology and also for a particularly low weight. At least the plastic of the profile frame 19 is magnetizable, such as by the above-described inclusions of metal particles, which can become permanent magnets themselves by the action of an external magnetic field. This allows a metal particle-saving production of the spray arm. Alternatively, it would of course also be possible to provide the shells 20, 21 with metal particles themselves and to magnetize.

As at the cut surfaces FIG. 2 it can be seen, the profile frame are provided with an inner structure in the manner of an undercut or staple structure and thus hold the shells 20, 21 firmly pressed together, they have for this over their entire edge region large contact flanges 23. The edge-side contact flanges 23 of the upper shell 20 and the lower shell 21 are largely flush and contacting each other. In particular, the respective profile frame 19 by its inner edge-side clamp structure a groove for receiving, ie clasping the lateral, web-like, superposed edge flanges 23 of the two shells 20, 21 ready, so that a tongue and groove connection is formed.

LIST OF REFERENCE NUMBERS

1

Dishwasher,

2

rinse tank,

3

Door,

4

spray arm,

5

spray arm,

6

Dish rack,

7

Dish rack,

8th

Axis of rotation

9

spray nozzle,

10

Collecting pot,

11

circulation pump,

12

Heater,

13

distribution space,

14

Drain pump,

15

Sewage lead,

16

rinsing tank,

17

screening,

18

Sensor,

19

Frame profile,

20

upper shell,

21

lower shell,

22

Cavity,

23

contact flange,

FW

Fresh water,

S

rinsing,

AW

Sewage,

Claims (10)

1. Dishwasher (1), in particular household dishwasher, having a rinsing container (2), in which inserted items to be washed, in particular crockery, cutlery and/or other cooking utensils, can be exposed to a circulating liquid (S), wherein the circulating liquid (S) can be introduced into the rinsing container (2) by means of at least one rotatable spray arm (4;5) and wherein the latter's rotational frequency can be measured by means of magnetic detection (19;18),
   characterised in that
   the or each spray arm (4;5) is formed at least in part (19) from a magnetisable plastic material, in particular from a magnetisable material based on a plastic matrix.
2. Dishwasher (1) according to claim 1,
   characterised in that
   the spray arm (4;5) is a single-piece or multi-piece (20;21;19) injection-moulded part.
3. Dishwasher (1) according to one of claims 1 or 2,
   characterised in that
   metal parts are embedded into the plastic material, in particular into the plastic matrix.
4. Dishwasher (1) according to one of the preceding claims,
   characterised in that
   while the magnetisable parts (19) of the spray arm (4;5) are being injection-moulded in an injection-moulding device or on a subsequent assembly line they are exposed to at least one external magnetic field for orientation of metal parts and/or for introduction of a preferred direction of magnetisation.
5. Dishwasher (1) according to claim 4,
   characterised in that
   the external magnetic field for orienting metal parts is effective in a phase in which the plastic of the spray arm (4;5) is at least in part (19) still soft.
6. Dishwasher (1) according to one of the preceding claims,
   characterised in that
   individual wings of the spray arm (4;5) are differently magnetised.
7. Dishwasher (1) according to claim 6,
   characterised in that
   individual wings can be introduced into overall magnetisation devices for differentiated magnetisation of the wings in the production device.
8. Dishwasher (1) according to one of the preceding claims,
   characterised in that
   the or each spray arm (4;5) comprises at least one region (19) over almost all or all of its total longitudinal side which is made of a magnetisable plastic material, in particular a magnetisable material based on a plastic matrix.
9. Dishwasher (1) according to one of the preceding claims,
   characterised in that
   the or each spray arm (4;5) comprises an upper (20) and a lower shell (21) which are connected to each other at the edge by means of surrounding profile frames (19).
10. Dishwasher (1) according to claim 9,
    characterised in that
    the profile frames (19) are formed of magnetisable plastic.

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