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(11) | EP 0 631 755 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Improved dishwashing machine |
| (57) A dishwashing machine is described, comprising a washing chamber (3) wherein at least
a crockery basket (4) is housed to which a vertical tubular element (9) is associated,
the upper end of said vertical tubular element (9) being able to receive a liquid
flow exiting the end of a conduit (11) coming from a pump (6), said end of said conduit
(11) being upstream, substantially coaxial and at a certain distance from said vertical
tubular element (9), and the lower end of said vertical tubular element (9) being
connected to a spraying organ (8), in particular rotatable around the axis of said
vertical tubular element (9). The main feature of the described dishwashing machine
consists in the fact in the internal upper wall (3A) of said washing chamber (3),
in correspondence of said end of said conduit (11), a terminal element (10) is provided
having variable length, which, when said spraying organ (8) is supplied with liquid
in pressure coming from said pump (6) through said conduit (11), lengthens downwards
in the way of eliminating the distance existing between said end of said conduit (11)
and said vertical tubular element (9). |
[0001] The present invention refers to a dishwashing machine as described in the preamble of the annexed claim 1.
[0002] As is known, modern dishwashing machine are provided with a washing chamber wherein an upper crockery basket and a lower crockery basket are arranged; dishes are sprinkled by means of two rotary collectors, that spray the washing liquid onto the dishes, and which are fed with liquid in pressure coming from a suitable washing pump, arranged in the basement of the machine. The lower collector is generally fed, and supported, by means of a tubular element from the bottom, directly from body of the pump, while the upper collector is normally fed from the top: a nozzle arranged in the roof of the washing chamber, supplied through a conduit coming from the pump, sends downwards a liquid jet and said jet, after having crossed an air gap, reaches a suitable funnel-shaped receiving element, fixed to the upper basket of the machine; the air gap separating the nozzle and the receiving element is provided for allowing the horizontal sliding of the basket, for the normal crockery loading and unloading operations.
[0003] The receiving funnel element, that bears the upper rotary collector and is in communication with it, usually uses a Venturi tube system, for avoiding turbulences and regurgitations in the flow of the liquid.
[0004] The liquid jet that exits the nozzle, however, crosses the free air gap and enters with an high speed in the receiving funnel element, hiting the walls of the latter and generating a noise that can be heard for all the duration of the washing, so making the apparatus noisy.
[0005] Furthermore, the upper basket of the dishwashing machine usually is adjustable in height (i.e. capable of assuming two different positions, an higher one and a lower one, inside of the washing chamber), and the free air gap may be greater or minor, depending on the conditions of use of the dishwasher; it is clear that when the upper rack is placed in the lower position, the distance' in air that the flow has to follow is greater; in such a case therefore the possibility that a part of the liquid misses the receiving funnel element is increased, and so finishes out of it, decreasing the efficiency of the washing; another negative effect in such a condition of use is a greater noise developed by the flow for entering the funnel. In the attempt to solve the problem of minimizing the noise and the losses of the flow in pressure, dishwashing machine machines have been proposed, equipped with means apt at eliminating, during the use of the machine, the air gap existing between the upper nozzle and the receiving funnel element.
[0006] For example, from document DE-A-3.540.238, a dishwashing machine is known, wherein the receiving element is surrounded by a movable tubular piece, at the upper end of which a funnel is obtained. The upwards mobility of the tubular piece, i.e. up to the nozzle, may be realized by manually adjusting the position of the movable element, through appropriate means and depending on the necessity; such a solution is not however practical and functional for the user of the dishwashing machine. In another embodiment described in the cited document, the movable piece and the receiving element are designed in a way to take advantage of the same liquid jet, for obtaining an automatic raising of the movable tubular element, so to eliminate the air gap between the receiving element and the nozzle (a solution substantially similar to the last one is also known from document FR-A-2.651.427).
[0007] The solutions of the cited type have however the drawback of requiring a certain precision of the supply jet, and of being subject to possible malfunctioning in the case of imprecise arrangement of the receiving element, in respect of the nozzle, which would produce pressure losses in the received flow.
[0008] From document EP-A- 509.251 a dishwashing machine is also known, wherein the cited air gap is surrounded by a tubular liquid jet; according to such a solution, which implies the existence of an annular opening for the liquid around to the main nozzle, the alignment between nozzle-annular opening and the receiving element must be almost perfect. Such a solution shows therefore a certain manufacturing complexity and fragility and is more subject to the above cited malfunctioning.
[0009] Aim of the present invention is to solve the above mentioned problems and in particular to show an improved dishwashing machine, wherein, with simple, reliable and efficient means, losses of the coming liquid jet from the upper nozzle are avoided, and the related noise is as low as possible.
[0010] Such aims are reached according to the present invention by a dishwashing machine incorporating the characteristics of the annexed claims.
[0011] The characteristics and advantages of the improved dishwashing machine according to the invention will appear from the following description, made with reference to the annexed drawings, which are supplied as a not limiting example, wherein:
- figure 1 schematically represents in section a dishwashing machine according to the present invention;
- figure 2 schematically represents in section a part of the dishwashing machine according to invention, which shows the supply system of the upper rotary collector in a first condition of use;
- figure 3 schematically represents in section a part of the dishwashing machine according to invention, which shows the supply system of the upper rotary collector in a second condition of use;
- figure 4 schematically represent in section a part of the dishwashing machine according to invention, which shows the supply system of the upper rotary collector, according to a possible variant of the present invention.
[0012] Some elements of the dishwashing machine according to invention will not be represented and/or described in the following of the present description, inasmuch as they are of known realization and operation.
[0013] In figure 1, with 1 the dishwashing machine according to the present invention is indicated as a whole; such a dishwasher 1 has a cabinet 2 and a washing chamber 3, into which an upper basket 4 and a lower basket 5 are arranged.
[0014] As in the prior art, on the opposite sidewalls of the washing chamber 3 sliding guides are provided, in which two series of rollers, being at the sides of the upper basket, can selectively be engaged, at different height levels. In this way, the upper basket 4 is susceptible to assume two positions in the inside of the washing chamber, depending of the washing necessity of the user.
[0015] Under each basket a rotary collector is disposed, being able to spray the dishes; as can be seen in figure 1, it is provided to this purpose a washing pump 6, which directly supplies the lower sprinkler, indicated with 7; the upper rotary sprinkler, indicated with 8, which is sustained by the upper basket 4, communicates with a vertical tubular element 9, the axis of which substantially coincides with the rotation axis of the upper sprinkler 8.
[0016] With 10 an upper supply device for the upper sprinkler is indicated as a whole, through which a liquid jet is sent in the vertical tubular element 9; such a device is supplied through a conduit 11 coming from pump 6.
[0017] In figure 2 the terminal device 10 is illustrated in detail, by a vertical section. In such a figure, with 11 the conduit coming from pump 6 is indicated, and which exits in the roof 3A of the washing chamber 3; with 12 a gasket is shown, with 13 an intermediate bush is shown, being double threatened and screwed onto the end of the conduit 11.
[0018] The terminal device 10 includes a telescopic element, composed by three sleeves having different diameter, which slide one inside the other; the upper sleeve, indicated with 15, has a thread that allows its screwing on the external thread of bush 13; between the upper sleeve 15 and the intermediate sleeve, indicated with 16, a spiral spring 17 is arranged; in the same way, a spiral spring 18, is arranged between the intermediate sleeve 16 and the smaller one, indicated with 19. The different sleeves provide appropriate reference elements, visible in 15A, 16A, 16B and 19A, being able to prevent the exit of a sleeve in respect of the other, and also having the function of support elements for the springs 17 and 18; the two springs 17 and 18, pressing on the two reference elements_16A and 19A, hold the sleeves 16 and 19 inside of the sleeve 15.
[0019] The smaller sleeve 19 realizes in practice the upper nozzle of the dishwasher, from which the supply jet for the tubular element 9 of the upper sprinkler exits; as can be seen, the internal surface of the sleeve 19 realizes a duct having a frusto conical or funnel shape.
[0020] The upper part of the sleeve 19 has an external diameter slightly smaller than the internal diameter of the end of the conduit 11, so that the former can partially enter the latter, in absence of the liquid flow, in order to reduce the encumbrance of the device 10 in the resting position. At the lower end of the smaller sleeve, or nozzle, 19 a flexible element 20 is hooked, having a throughole, for example a rubber membrane, of rounded shape and having a diameter substantially coincident with that of the upper part of the tubular element 9.
[0021] In the resting position, or when the pump 6 does not operates, between the flexible element 20 and the upper end of the tubular element 9 a space is present, which allows the extraction of the upper basket, for the normal loading/unloading operations of the dishes.
[0022] In figure 2 the upper basket 4 of the dishwasher machine, not visible, is in the highest position, in absence of water supply; the device 10 is therefore in the resting position and, as can be seen, in such a condition the thrust of springs 17 and 18 maintains the sleeve 16 and the nozzle 19 substantially within the overall dimensions of the sleeve 15 (the overall dimensions of which is substantially in the order of the vertical overall dimensions of the nozzles in the commonly used dishwashing machine); in particular, the funnel defined in the sleeve 19 directly faces the end of the conduit 11.
[0023] When the upper rotary collector has to be supplied, the pump 6 provides to send of the liquid along the conduit 11, until the device 10.
[0024] When the liquid exits from the end of the conduit 11, its pressure and the funnel shape of the nozzle 19 are such to determine the downwards displacement of the nozzle 19, that slides within the intermediate sleeve 16 in opposition to the action of the spring 18. The displacement of the nozzle 19 causes, through the reference element 19A, the spring 18 and the reference element 16B, also the downwards displacement of the sleeve 16. The nozzle 19 and the sleeve 16 moves so downwards, until the flexible element 20 rests on the upper end of the vertical tubular element 9; in this way no air gap remains between the nozzle and the receiving element 9 and, consequently, the noise produced by the jet of the washing liquid is drastically reduced and the risk of losses in the supply jet of the upper collector is avoided.
[0025] If the upper basket is in the highest position, the maximum excursion of the movable nozzle 19 and annexed sleeves is not necessary, but it is sufficient an intermediate displacement, until the flexible element 20 gets in contact with the tubular element 9; instead if the upper basket is in the lower position, the receiving element 9 is in the position illustrated in figure 2 by the dotted-line; in such a case, during the water supply, also the intermediate sleeve 16 slides downwards within the upper sleeve 15, against the action of the spring 17; in figure 3, which exactly illustrates such a condition, it can be seen how the lowering of the nozzle 19 determines also the lowering of the intermediate sleeve 16. It is clear that the springs 17 and 18 will be duly chosen, so that the load required for compressing them is not excessive, but it is sufficient the pressure the liquid exerts on the internal tubular walls of the nozzle 19.
[0026] When the supply of the upper collector must end, the pump 6 stops sending the liquid to the device 10, through the conduit 11; as can be imagined, in this way the nozzle 19 and the sleeve 16, which are no longer subject to the pressure of the liquid, will return in the native resting positions, under the action of the springs 17 and 18: we are thus again in the condition visible shown in figure 2.
[0027] By appropriately choosing the sections of the sleeve 16 and of the nozzle 19, liquid losses are avoided; it is then clear that the sizes, in particular the length, of the different sleeves will be selected according to the width of the air gap that has to be eliminated.
[0028] In figure 4, where a possible alternative embodiment of the dishwashing machine according to the present invention is illustrated, part of the same reference numbers of the previous figures are used, for indicating similar elements.
[0029] In such a figure 4, with reference number 21 a rubber disk is shown, having a through central hole, having a diameter being substantially greater in respect of that of the upper end of the vertical element 9; the disk 21 is fixed to the lower end of the nozzle 19, for example by means of screws, two of which are shown at 22.
[0030] The greater diameter of the disk 21 has the function of compensating the eventual positioning imprecision of the vertical receiving element 9. In fact, as it can be seen in part B of the figure, also in the case of misaligned placement between the nozzle 19 and the element 9, the opening of the latter is covered by disk 21, so as that the noise and the risk of pressure losses in the liquid flow are in any way avoided.
[0031] Furthermore, in the embodiment illustrated in figure 3, seats 16A and 19A of sleeves 16 and 19 are suitably shaped, in order to favour the passage of the liquid flow through the device 10.
[0032] From the given description the characteristics of the dishwashing machine subject of the present invention are clear, as clear are its advantages.
[0033] In particular they are represented by the fact that in the dishwasher according to invention losses are avoided in the supply jet of the upper collector, and at the same time a drastic reduction of the noise during the operation of the machine is obtained; the adopted solution is simple, reliable, compact and elegant, and can be applied onto any type of machine; the intervention on the device 10, for maintenance and cleaning, is simple and quick.
1. Dishwashing machine, comprising a washing chamber (3) wherein at least a crockery
basket (4) is housed to which a vertical tubular element (9) is associated, the upper
end of said vertical tubular element (9) being able to receive a liquid flow exiting
the end of a conduit (11) coming from a pump (6), said end of said conduit (11) being
upstream, substantially coaxial and at a certain distance from said vertical tubular
element (9), and the lower end of said vertical tubular element (9) being connected
to a spraying organ (8), in particular rotatable around the axis of said vertical
tubular element (9), characterised in that in the internal upper wall (3A) of said
washing chamber (3), in correspondence of said end of said conduit (11), a terminal
element (10) is provided having variable length, which, when said spraying organ (8)
is supplied with liquid in pressure coming from said pump (6) through said conduit
(11), lengthens downwards in the way of eliminating the distance existing between
said end of said conduit (11) and said vertical tubular element (9).
2. Dishwashing machine, according to claim 1, characterized in that said terminal element
(10) is of variable length against the action of elastic means (17,18).
3. Dishwashing machine, according to claim 1 or 2, characterized in that said terminal
element (10) of variable length is of the telescopic type and has two or more sleeves
(15, 16, 19) having different diameter, at least one of said sleeves (16,19) being
sliding within an other of said sleeves (15,16) in contrast to the action of a spiral
spring (17,18).
4. Dishwashing machine, according to claim 3, characterized in that the sleeve having
smaller diameter (19) of said telescopic terminal element (10) constitutes the nozzle
from which the liquid flow exits, which supplies, through said vertical tubular element
(9), said spraying organ (8).
5. Dishwashing machine, according to claim 4, characterized in that in said sleeve of
smaller diameter (19), that it is in particular the last sleeve of said telescopic
terminal element (10), is obtained a frusto conical or funnel shaped duct.
6. Dishwashing machine, according to at least one of previous claims, characterised in
that, when said spraying organ (8) is not supplied with liquid in pressure coming
from said pump (6) through said conduit (11), the reaction of said elastic means (17,18)
is able to maintain said sleeves (15,16,19) substantially one inside the other, in
such a condition the overall dimensions in height of said sleeves (15,16,19) being
in particular contained within the overall dimensions of the sleeve of greater diameter
(15).
7. Dishwashing machine, according to at least one of previous claims, characterised in
that, when said spraying organ (8) is supplied, the pressure of the liquid coming
from said pump (6) and exiting said conduit (11) is apt at determining the downwards
displacement of at least one of said sleeves (16,19), winning the action of the relevant
elastic means (17,18), exercising a force on the internal wall of the funnel duct
provided inside said sleeve of smaller diameter (19).
8. Dishwashing machine, according to at least one of previous claims, characterised in
that the upper part of the sleeve having smaller diameter (19), has external dimensions
being minor of the internal dimensions of the end of said conduit (11), in order to
be able to enter therein at least partially, in absence of liquid in pressure coming
from said pump (6)
9. Dishwashing machine, according to at least one of previous claims, characterised in
that in the lower part of said sleeve of smaller diameter (19), an element (20;21)
is present for the resting on the upper end of said vertical tubular element (9),
said sleeve of smaller diameter (19) moving in particular downwards until said resting
element (20;21) reaches the upper end of said vertical tubular element (9).
10. Dishwashing machine, according to the previous claim, characterised in that said resting
element is a membrane in flexible material (20), in particular in rubber, fixed to
said sleeve of smaller diameter (19) and having a diameter substantially coincident
to that of the upper end of said vertical tubular element (9).
11. Dishwashing machine, according to claim 9, characterised in that said resting element
is a disk in flexible material (21), in particular in rubber, having a through central
hole, the diameter of said disk (21) being substantially greater in respect of that
of the upper end of said vertical tubular element (9) and therefore able to compensate
the eventual positioning imprecision of the latter.
12. Dishwashing machine, according to at least one of previous claims, characterised in
that said terminal element includes a bellow element, in particular in rubber
13. Dishwashing machine, according to at least one of previous claims, characterised in
that said end of said conduit (11) partially exits from the upper surface (3A) of
said washing chamber (3) and that the sleeve of greater diameter (15) is screwed on
it, in particular by means of an intermediate bush (13) having a double thread.
14. Dishwashing machine, according to at least one of previous claims, characterised in
that said sleeves (15,17,19) provides reference elements (15A,16A,19A), apt at preventing
the exit of a sleeve in respect of the other and apt at also realizing support elements
for said springs (18,19), said reference elements being in particular shaped in order
to favour the passage of the liquid flow which pass through said telescopic terminal
element (10).
15. Dish-washing machine, according to claim 1, characterized in that said basket (4)
is apt at assuming at least two different positions in height inside of said washing
chamber (3).