AU2010280878B2

AU2010280878B2 - Water-bearing domestic appliance

Info

Publication number: AU2010280878B2
Application number: AU2010280878A
Authority: AU
Inventors: Bernd Heisele; Michael Lugert; Karl Wirth
Original assignee: BSH Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2009-08-06
Filing date: 2010-07-22
Publication date: 2013-08-01
Anticipated expiration: 2030-07-22
Also published as: WO2011015464A1; EP2461732B1; AU2010280878A1; EP2461732A1; DE102009028277A1

Abstract

The invention relates to a water-bearing domestic appliance, in particular a dishwasher, having a liquid line (23) in which a valve (26) is arranged, said valve having an adjustable valve element (45) which interacts with a valve seat (49) in order to open and close the valve (26). According to the invention, the valve seat (49) or the valve element (45) is designed, at least partially, to have a substantially sharp-edged severing edge with which particles (61) of dirt between the valve seat (49) and the valve element (45) can be cut off during a closing process of the valve (26).

Description

Water-bearing domestic appliance The invention relates to a water-bearing domestic appliance, in particular a dishwasher, having a liquid line in which a valve is arranged, said valve having an adjustable valve element which interacts with a valve seat in order to open and close the valve. During a washing process, dishwashers perform washing programs comprising a number of sub-program stages, such as pre-rinse, wash, interim rinse, clear rinse and dry. In order to distribute liquid while a washing program is being run, the liquid circuit in a dishwasher has valves to open or close a liquid path. However, particles of dirt in the liquid may block a valve. Object of the Invention It is the object of the present invention to substantially overcome or ameliorate one or more of the above disadvantages. Summary of the Invention The present invention provides a water-bearing domestic appliance, in particular a dishwasher, having a liquid line in which a valve is arranged, said valve having an adjustable valve element which interacts with a valve seat in order to open and close the valve, wherein the valve seat or the valve element is designed, at least partially, to have an essentially sharp edged severing edge with which particles of dirt between the valve seat and the valve element can be cut off during a closing process of the valve, and wherein the severing edge protrudes into a valve chamber on the valve which is subject to a flow of liquid. This arrangement does not have any adverse effect upon the sealing function between the valve element and the valve seat, since it is not possible for any particles of dirt to settle around the flow gap between the valve element and the valve seat. The valve is therefore most suitable for use in the soiled water and service water section of a water-bearing domestic appliance. In order to ensure that clinging particles of dirt are cut off, the cross-section of the severing 2 edge may run at an acute angle towards the adjustable valve element. A cutting function may be guaranteed in particular if the severing edge runs at an angle of between 300 and 50*. An acute angle of 450 is preferable. In such a case, the severing edge is still sufficiently sharp edged on the one hand and sufficiently stable in form on the other hand; furthermore, it is still straightforward to manufacture in a plastics injection molding process. In addition, efforts should be made to prevent operational damage to the sealing surface of the valve element, such as can occur if the valve seat is designed with edges which are too sharp. It has therefore been proven to be beneficial to provide the severing edge with a rounded edge at its tip, in particular with a radius of around 0.3 mm. The valve seat which is designed as a severing edge may e.g. be designed to have rotational symmetry and may define a nozzle aperture for the liquid line. The rotationally symmetrical external contours of the severing edge may in such a case be designed to be tapered, in order to achieve the sharp-edged geometry for the valve seat mentioned above. With the valve in the closed status, the adjustable valve elements can be pressed against the severing edge in such a way as to be liquid-tight. With the valve in the open status, on the other hand, the valve element can be displaced from the valve seat by means of a valve stroke, whereby an flow gap to the nozzle aperture is created, making it possible for liquid to flow through the valve. As mentioned above, the valve seat designed as a severing edge can be used to keep the sealed area between the valve seat and the valve element essentially free of particles of dirt, thus ensuring flawless operation of the valve. Instead of the sealing surface being oriented on a horizontal plane, it has been proven favorable for a sealing level to be aligned towards a horizontal plane of this nature, and in particular for it to be vertical in orientation. Particles of dirt around the flow gap between the valve seat and the valve element are not therefore able to settle in this area; instead, they are simply carried away from the flow gap by the force of gravity.

PCT/EP2010/060624 / 2008P04584WOAU 3 / 15 In order to assist with cutting off particles of dirt lodged in the flow gap, the valve element can be pressed against the severing edge with a high level of thrust by means of an actuator. Electromagnetic actuators or thermoactuators can be considered as actuators. In view of the high level of actuating force, it is preferable to use a thermoactuator, wherein an extensible material, such as wax, is extended upon energization, which makes it possible to achieve especially high levels of actuating force. In order to create a perfect seal, that side of the valve element which faces the valve seat can be made of an elastic material, such as silicon. The elastic material can be designed to be sufficiently yielding that, with the valve in the closed status, the severing edge can be pressed into the valve element at a specified depth of penetration, in order to guarantee that any particles of dirt which may have become lodged are cut off. If the valve seat is to operate as required, it is preferable for said depth of penetration to be in the range between 0 and I mm. It is possible to assist removal of particles of dirt already inside the valve from the sealed area between the valve seat and valve element by having the liquid line feeding downwards from its nozzle aperture into the valve at a specified gradient, in the manner of a siphon, whereby the gradient of the line can cause the particles of dirt to accumulate at the base of the siphon. It is also possible to assist the removal of particles of dirt in the flow area between the valve element and the severing edge by providing a vertical clearance underneath the severing edge where the particles of dirt can accumulate. It is preferable if the clearance feeds directly by means of an outlet into the liquid pipe as it extends further, so that the particles of dirt can be displaced externally from the valve chamber through the outlet by the force of gravity. It is preferable for the invention to be used in a dishwasher which has an additional storage container in particular. The storage container can be used for temporary storage of that washing liquor which is no longer required after a subprogram stage of a rinsing process has been completed. The washing liquor no longer required is pumped from the rinsing chamber into the storage container by means of a circulation pump and with the storage container valve open. The storage container valve is then closed and the washing liquor held in temporary storage until the next rinsing process, for example, where it is used to pre-rinse the items to be washed during the next rinsing process. In order to manage filling and emptying of the storage container, there is provision for a storage container valve, which can be used by a control PCT/EP2010/060624 / 2008PO4584WOAU 4/15 device in the dishwasher to open or close the liquid path to the storage container. The storage container valve is arranged fluidically between the washing liquor container and the storage container, i.e. in the soiled water or service water area of the dishwasher. This presents the problem that, with the valve open, it is possible for particles of dirt to cling within the storage container valve and to become lodged there. In such a case, the valve can become faulty or leak, leading to a malfunction in the storage container. In order to feed the temporarily stored washing liquor back into the liquid circuit for the dishwasher, the storage container valve is opened, allowing the washing liquor to flow out of the storage container. The washing liquor can then flow from the storage container into the washing compartment of the dishwasher under the force of gravity, i.e. at low speed. In the event of a fault in the storage container valve, the discharge of the washing liquor from the storage container is critical. In such an event, there is a particular risk that particles of dirt will also be carried off from the storage container and will be able to clog the storage container valve. On the other hand, washing liquor is pumped into the storage container by means of the circulation pump when the storage container is being filled. The base of the siphon is therefore subject to rapid flushing on a regular basis, which makes it possible to prevent any blockage of the siphon. Another preferred embodiment provides for the severing edge to be designed to border all or part of a nozzle aperture in the liquid line, whereby the nozzle aperture in the liquid line can have a circular or other e.g. oval cross-section. Furthermore, it is also preferable for the severing edge to be circular in form, in cases where it borders all of the nozzle aperture, and curved in form, where it borders part of the nozzle aperture. Other versions of the severing edge are also possible, however, e.g. with abrupt transitions in the form of kink sections, such as rectangular, pentagonal or hexagonal shaped embodiments of the severing edge. Other forms, such as star shapes, are also possible.

FU I /EIP2010/060624 / 2008P04584WOAU 5 / 15 Finally, there is a benefit in the arrangement whereby the severing edge bordering part of the nozzle aperture is arranged in the area where particles of dirt are deposited as a consequence of gravity and/or flow. With a essentially horizontal liquid line in the area of the nozzle aperture, for example, the severing edge may be arranged in the lower section of the nozzle aperture, e.g. in the lower semi-circle in the case of a nozzle aperture with a circular cross section, since this is where experience suggests that particles of dirt are likely to accumulate. There follows a description of an exemplary embodiment of the invention, using the figures attached. Wherein: Fig. 1 shows, in a schematic block diagram, a dishwasher with a storage container; Fig. 2 shows, in an enlarged lateral sectional view, the storage container valve connected to the storage container during discharge of the washing liquor in temporary storage; Fig. 3 shows, in a view consistent with Fig. 2, the storage container with closed storage container valve; Fig. 4 and 5 show enlarged sectional views of the storage container valve in various operating states respectively; and Fig. 6 shows a detailed view of the sealed zone between the valve seat and the adjustable valve element in the storage container valve. Fig. 1 provides a schematic illustration of a dishwasher with a washing container 1 defining a washing area. The items to be washed, which are not illustrated, can be arranged in cutlery baskets 3, 5 in the washing area of the washing container 1. The washing container I illustrated includes, for exemplary purposes, two spray arms 7, 8 arranged at different spray levels, which can be used to apply washing liquor to the items to be washed. There is a sump 11 with a filter arrangement 10 which is indicated in outline only in the base of the washing container. A circulating pipe 9 with a circulation pump 13 arranged inside leads away from the sump 11. The circulating pipe 9 has a fluidic connection with the spray arms 7, 8 by PCT/EP2010/060624 / 2008P04584WOAU 6/15 means of feed lines 14, 15. A heating element 12, designated as a water heater, is connected downstream of the circulation pump 13. The sump 11 is also connected, by means of stub fittings, to a freshwater feed pipe 16 connected to the mains water supply and to a discharge pipe 17, in which a detergent pump 18 is arranged in order to pump out washing liquor from the washing container 1. On its right hand side in Fig. 1, the washing container I has a "washing container", designated in Fig. I as washing container 19, which, in the manner of a heat exchanger, has a thermal connection with a side panel 20 of the washing container 1. The storage container 19 can be used for temporary storage of washing liquor which is no longer required once one section of the sub-program has been completed. The storage container 19 has an aeration and ventilation aperture 22 in its upper section which creates a fluidic connection with the washing area. While a washing process is being carried out, the liquid circuit includes, inter alia, the sump 11 with assigned filter arrangement 10, the circulating pipe 9, the feed lines 14, 15 and the two spray arms 7, 8. A water diverter in the form of a three-way control valve is provided downstream of the heating element 12 in the circulating pipe 9, from which a connecting pipe 23 branches off, leading to the storage container 19. In the operating position for the three-way control valve 25 illustrated in Fig. 1, the connection with the storage container 19 is interrupted and the circulating pipe 9 is connected to the feed lines 14, 15. In this operating position for the three-way switching valve 25, therefore, the washing liquor can be circulated in the dishwasher in order to conduct the washing cycle. On the other hand, in an operating position not illustrated in Fig. 1, the three-way control valve 25 connects the circulating pipe 9 with the connecting pipe 23 leading to the storage container 19 and interrupts the fluidic path to the feed lines 14, 15. In this operating position, it is possible to pump the washing liquor into the storage container 19 at a high flow rate in PCT/EP2010/060624 / 2008P04584WOAU 7/15 order to clean the storage container 19 and fill it until the washing liquor is fed into the washing container 1 by means of the aeration and ventilation aperture 22 and is fed back into the sump 11 with assigned filter arrangement 10, past the side panel of the washing container 20 and into the cutlery baskets 3, 5. This makes it possible to draw particles of dirt, fatty residues, etc. out of the storage container 19. A storage container valve 26 is provided to ensure that loading or emptying of the storage container 19 can be controlled by means of the control device 27. The valve 26 is arranged in the connecting pipe 23 leading to the storage container 19 and is in its open position during the cleaning of the storage container mentioned above, for example. For example, the washing process can be started with a pre-rinse stage, in which a volume of clear rinse water from the previous washing process held in temporary storage in storage container 19 is released into the sump section of the washing container 1. To this end, the storage container valve 26 is opened and the three-way valve 25 is adjusted as appropriate. The volume of clear rinse water held in temporary storage is therefore able to flow into the sump section of the washing container 1 simply through the force of gravity. The three-way valve 25 is then switched back into its switching position as illustrated in Fig. 1 and the circulation pump 13 is started, which makes it possible for the clear rinse water released from the storage container 19 to circulate. Once the pre-rinse stage has been completed, the washing liquor is pumped out by means of the washing liquor pump 18; fresh water for a subsequent cleaning stage is then fed into the sump section. As illustrated by Fig. 2, the connecting pipe 23 leading from storage container 19 is connected with a valve chamber 31 in the storage container valve 26 by means of a nozzle aperture 29. The valve chamber 31 also has an external radial limit, in the form of a connector fitting 33. The fitting 33 is connected with the underside of the storage container 19 by means of two reinforcing ribs 35. On its base, the valve chamber 31 also feeds, by means of a duct 37, back into the connecting pipe 23, which can be connected to the water diverter 25 by means of a stub fitting 39. Starting from the duct 37 on the base of the valve 26, the connecting pipe 23 is fed vertically downwards by means of a U-shaped curve.

PCT/EP2010/060624 / 2008P04584WOAU 8 / 15 The connector fitting 33 defining the valve chamber 31 has a thermoactuator 41 for the storage container valve 26 inserted in it, whereby a valve head 45 which can be adjusted by means of a valve lift is attached to the valve tappet 43. Fig. 2 shows the adjustable valve head 45 in its open position, while in Fig. 3 it is in its closed position, in which the sealing points 47 of the valve head 45 and of the valve seat 49 are pressed close up against one another in order to form a seal. On the circumference, the valve seat 49 is extended around the nozzle aperture 29. The sealing points or sealing areas 47 of the valve seat 49 and of the valve head 45 are oriented in a vertical plane, in accordance with Fig. 3. In accordance with Figs. 2 to 5, the valve head 47 is an integral component part of a membrane element 51, which takes the form of an essentially rotationally symmetrical silicon component. The open annular end of the rotationally symmetrical membrane element 51 is fitted in an annular gap between the connector fitting 33 and an internal connecting sleeve 55 of a housing section 57. The thermoactuator 41 is not therefore fitted directly into the connector fitting 33; instead, the housing section 57 lies in between. As illustrated in Fig. 3, the liquid line 23 has a siphon 59 between the storage container valve 26 and the storage container 19, which is designed to keep those particles of dirt 61 indicated in Fig. 3 away from valve 26. The siphon 59 takes the form of two essentially vertical pipe sections 62 and 63 which run in opposing directions. The two pipe sections 62, 63 are each connected directly to the nozzle aperture 29 on the valve 26 and to a duct on the storage container 19. The pipe section 62 from the siphon 59 drops down directly from valve 26 with an increasing degree of inclination a and passes, via the base of the siphon 64, to the pipe section 63 which leads to the storage container 19. Starting from the nozzle aperture 29, therefore, the pipe section 62 from the siphon 59 is inclined downwards by degree of inclination a as standard, whereby the force of gravity makes it possible for the particles of dirt 61 to be carried away from the valve 26 to the base of the siphon 64. The base of the siphon 64 is arranged at a height difference Ah underneath the storage container valve 26.

PCT/EP2010/060624 / 2008P04584WOAU 9/15 As shown by Figs. 4 and 6 in particular, the valve seat 49 is sharp-edged on the side facing the valve head 45. This means that particles of dirt can be severed between the valve seat 49 and the valve head 45 during a closing process for the valve head 45, as illustrated in Figs. 4 and 5. Consequently, Fig. 4 shows an elongated particle of dirt 61 which has become lodged in the valve seat 49 while the storage container 19 was being emptied. When valve 26 is closed, the particle of dirt 61 is severed into two sections as per Fig. 5, whereby one severed section is moved by the force of gravity through the duct 37 into the next stage of the liquid line 23. The other section can also be moved to the base of the siphon 64 by the force of gravity. The schematic diagram in Fig. 6 shows the geometry of the valve seat 49 which takes the form of a severing edge. This shows the external contours 65 of the severing edge 49 as tapered and the severing edge as running at an acute angle 0 of approximately 450 towards the valve element 45. The tip of the severing edge 49 is slightly rounded off. In the present exemplary embodiment, on the other hand, the valve element 45 takes the form, in the area of its sealing surface 47, of a silicon material which is sufficiently soft as to allow the severing edge 49 to be pressed into the silicon material of the valve element 45 up to a depth of penetration a in the range of I to 2 mm. The severing edge 49 is therefore in virtually tangential contact with the sealing surface 47 of the valve element 45. The dotted line in Fig. 6 indicates a cone whose surface area contains the external contours 65 of the valve seat 49. Figs. 2 and 3 below describe various operational states for the dishwasher. Thus, Fig. 3 shows the storage container valve 26 in its closed position, whereby the washing liquor pumped into the storage container 19 beforehand can be stored temporarily. The particles of dirt 61 in the storage container 19 and in the connecting pipe 23 are therefore deposited, over the course of time, onto the base of the storage container 19 or onto the base of the siphon 64. The storage container valve 26 remains essentially free of particles of dirt 61 around the area of the sealing surfaces 47. Fig. 2 shows the storage container valve 26 in its open position, whereby the valve element 45 has been moved to the left by one valve stroke. This clears an flow gap between the valve element 45 and the valve seat 49. The washing liquor held in temporary storage in the storage PCT/EP2010/060624 / 2008PO4584WOAU 10/15 container 19 is therefore released from the storage container 19 by the force of gravity and feeds back into the liquid circuit for the dishwasher. In direction of flow I, therefore, the washing liquor held in temporary storage flushes storage container valve 26. The difference in height Ah between the storage container valve 26 and the base of the siphon 64 is designed in such a way that the vast majority of the particles of dirt 61 trapped on the base of the siphon 64 cannot be carried as far as the storage container valve 26 by the flow I.

PCT/EP2010/060624 / 2008P04584WOAU 11/15 LIST OF REFERENCE CHARACTERS I Washing container 3, 5 Cutlery baskets 7, 8 Spray arms 9 Circulating pipe 10 Filter arrangement 11 Sump 12 Heating element 13 Circulation pump 14, 15 Feed lines 16 Fresh water supply pipe 17 Drainage pipe 18 Washing liquor pump 19 Storage container 20 Side panel of washing container 22 Aeration and ventilation aperture 23 Connecting pipe 25 Three-way switching valve 26 Storage container valve 27 Control device 29 Nozzle aperture 31 Valve chamber PCT/EP2010/060624 / 2008P04584WOAU 12/15 33 Connector fitting 37 Duct 39 Stub fitting 41 Thermoactuator 43 Valve tappet 45 Valve element 47 Sealing points 49 Valve seat, severing edge 51 Membrane element 55 Connecting sleeve 57 Housing section 59 Siphon 61 Particles of dirt 62, 63 Pipe sections 64 Base of siphon 65 External contours of severing edge I Direction of flow Ah Difference in height a Angle of inclination B Acute angle of severing edge a Depth of penetration

Claims

1. Water-bearing domestic appliance, in particular a dishwasher, having a liquid line in which a valve is arranged, said valve having an adjustable valve element which interacts with a valve seat in order to open and close the valve, wherein the valve seat or the valve element is designed, at least partially, to have an essentially sharp-edged severing edge with which particles of dirt between the valve seat and the valve element can be cut off during a closing process of the valve, and wherein the severing edge protrudes into a valve chamber on the valve which is subject to a flow of liquid.

2. The water-bearing domestic appliance as claimed in claim 1, wherein the severing edge is designed to be sharp-edged, in particular with an angle of between 300 and 504, where an angle of 450 is particularly preferable.

3. The water-bearing domestic appliance as claimed in claim I or 2, wherein the tip of the severing edge is rounded off, with a radius of around 0.3 mm in particular.

4. The water-bearing domestic appliance as claimed in any one of the above claims, wherein the external contours of the severing edge are embodied in conical form.

5. The water-bearing domestic appliance as claimed in any one of the above claims, wherein sealing surfaces are located in a sealing plane between the severing edge and the valve element, which is inclined towards a horizontal plane and in particular is oriented in a vertical direction.

6. The water-bearing domestic appliance as claimed in any one of the above claims, wherein the valve element can be pressed against the severing edge with a high level of actuating force by means of a control element, in particular by means of a thermoactuator. 14

7. The water-bearing domestic appliance as claimed in any one of the above claims, wherein the valve element is made of an elastic material, at least in the area of the sealing surface.

8. The water-bearing domestic appliance as claimed in any one of the above claims, wherein, in the closed state of the valve, the severing edge is pressed into the valve element with a depth of penetration in a range of 0 to 1 mm.

9. The water-bearing domestic appliance as claimed in any one of the above claims, wherein the liquid line has a nozzle aperture which is inclined downwards at an angle of inclination.

10. The water-bearing domestic appliance as claimed in any one of the above claims, wherein the valve chamber in the valve has a vertical duct on its base underneath the severing edge, which is connected to the liquid line.

11. The water-bearing domestic appliance as claimed in any one of the above claims, wherein the water-bearing domestic appliance has a storage container which can be used for temporary storage of washing liquor and the liquid line connects a washing container for the water-bearing domestic appliance with the storage container.

12. The water-bearing domestic appliance as claimed in claim 11, wherein, in a first direction of flow, the washing liquor held in temporary storage in the storage container flows, in particular when subject to the force of gravity, from the storage container into a washing chamber in the domestic appliance, wherein in an opposed second direction of flow, the washing liquor can be conveyed into the storage container by means of a circulation pump. 15

13. The water-bearing domestic appliance as claimed in any one of the above claims, wherein the severing edge is embodied to border all or part of the nozzle aperture in the liquid line, wherein the severing edge is designed to be circular or curved.

14. The water-bearing domestic appliance as claimed in claim 13, wherein the severing edge running around part of the nozzle aperture is arranged in the area where particles of dirt are deposited by gravity or by flow.

15. A water-bearing domestic appliance substantially as hereinbefore described with reference to the accompanying drawings. BSH Bosch und Siemens Hausgerite GmbH Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON