EP1659917A1

EP1659917A1 - Valve device

Info

Publication number: EP1659917A1
Application number: EP04749208A
Authority: EP
Inventors: Roger Fransson
Original assignee: Wexiodisk AB
Current assignee: Wexiodisk AB
Priority date: 2003-09-01
Filing date: 2004-08-18
Publication date: 2006-05-31
Also published as: SE0302333D0; WO2005020782A1; SE526140C2; SE0302333L

Abstract

A valve device (1), especially intended for a dishwasher, comprises a liquid container (3) with an upper liquid inlet (4) and a lower liquid outlet (5). It further has a valve seat (6) which is arranged in the container (3), and a float valve body (7) which is arranged in the container (3) and movable therein between an upper closed position, in which it abuts against the valve seat (6), and a lower end position. The valve device (1) has a holding means (11, 12) which is arranged to hold the float valve body (7) in the lower end position as the liquid level rises, until the liquid level has reached an upper limit position (9). Moreover the float valve body (7) has such great buoyancy that it is held in the closed position as the liquid level falls, until the liquid level has reached a lower limit position.

Description

VALVE DEVICE

Field of the Invention The present invention relates to a valve device, especially intended for a dishwasher, said valve device comprising a liquid container with an upper liquid inlet and a lower liquid outlet, a valve seat which is arranged in the container, and a float valve body which is arranged in the container and movable therein between an upper closed position, in which it abuts against the valve seat, and a lower end position.

Object of the Invention The object of the valve device according to the present invention is in particular to eliminate a problem in a one-compartment dishwasher of the type in which pre-rinsing liquid is recirculated and which is described in SE 520,854. Such a dishwasher comprises a dishwashing compartment and liquid tanks positioned under the same. Articles to be washed are placed in the dishwashing compartment and flushed with liquid, first dishwashing liquid, then pre-rinsing liquid and finally rinsing liquid. The pre-rinsing liquid is a mixture of the pre- rinsing liquid and rinsing liquid of the preceding dishwashing round and should be kept as clean as possible. All the liquid sprayed into the dishwashing com- partment in such a dishwasher is collected by a collecting plate arranged under the dishwashing compartment and above the liquid tanks . An opening in this plate is formed by an inlet tube which opens into a recirculation rinsing tank for pre-rinsing liquid. When the recircula- tion rinsing tank is full, also the inlet tube is full, which means that liquid cannot flow down in the tube and, thus, into the recirculation rinsing tank. In the pre-rinsing phase, liquid is pumped from this tank up to the dishwashing compartment, whereby the liquid level falls in the tank as well as the inlet tube and the liquid collected on the collecting plate can again flow down into the recirculation rinsing tank through the inlet tube. The recirculation rinsing tank is being filled again as soon as the liquid level of the inlet tube falls. This is a problem since the major part of the dirt is washed away during the introductory pre-rinsing phase and the liquid from this introductory pre-rinsing phase will thus be the dirtiest liquid. The object of the invention thus is in particular to eliminate this problem and provide a valve device which makes it possible to keep the liquid in the recirculation rinsing tank cleaner in a simple, reliable and inexpensive manner. More generally, the object of the invention is to provide a valve device with a delayed opening and closing function.

Summary of the Invention These objects are achieved by a valve device of the type mentioned by way of introduction, said valve device being characterised in that the valve device has a holding means which is arranged to hold the float valve body in the lower end position as the liquid level rises, until the liquid level has reached an upper limit position, and the float valve body has such great buoyancy that it is held in the closed position as the liquid level falls, until the liquid level has reached a lower limit position. The container is preferably an essentially vertical tube, but of course the container can also be a liquid tank. The holding means consists of a first holding element which is arranged on the float valve body, and a second holding element which is fixedly arranged on the container and adapted to magnetically cooperate with the first holding element. The holding means could also be a mechanical system involving, for example, links or springs which are actuated by the liquid in the container. Preferably one holding element is a magnet and the other holding element is made of a magnetic material. Of course, also both holding elements could be magnets. The float valve body suitably has an upper and a lower float held together by a narrow central portion, but the float valve body may be designed in other ways depending on, for instance, the shape of the container and/or how long a delay is to be provided. To provide a further holding effect, the valve device can have an additional holding means adapted to hold the float valve body in the closed position in cooperation with the same, until the liquid level has fallen to the lower limit position.

Brief Description of the Drawings The invention will now be described in more detail by means of an exemplifying but non-limiting embodiment which is schematically shown in the accompanying draw- ings . Fig. 1 is a side view and illustrates very schematically a dishwasher provided with a valve device according to the invention. Figs 2-8 are side views and illustrate schematically the valve device in Fig. 1 in a tube with a float valve body in different positions, Figs 2-5 showing the position of the float valve body as the liquid level falls, and Figs 6-8 showing the position of the float valve body as the liquid level rises. Description of a Preferred Embodiment A valve device 1 according to the invention has a special application in a one-compartment dishwasher 2 of the type shown in Fig. 1. The dishwasher 2 has a dish- washing compartment 16, in which articles to be washed are placed, and spray arms 17 which are adapted to spray liquid over the articles to be washed. A dishwashing tank 18 and a recirculation rinsing tank 19 are positioned under the dishwashing compartment 16. Under the dishwashing compartment 16 above the tanks there is a collecting plate 21, on which liquid sprayed into the dishwashing compartment 16 is collected. This plate 21 has an opening (not shown) which communicates with the dishwashing tank 18, and an opening which is made of an inlet tube 3 which opens into the recirculation rinsing tank 19. The valve device 1 according to the invention comprises the inlet tube 3 which has an upper liquid inlet 4 and a lower liquid outlet 5, a valve seat 6 which is arranged in the tube 3 at the inlet 4 and a float valve body 7 which is arranged in the tube 3. The float valve body 7 is movable in the tube 3 between an upper closed position, in which it abuts against the valve seat 6 (Figs 2-4 and 8), and a lower end position (Figs 5-7) . In the shown embodiment, the float valve body 7 has an upper and a lower float 13 and 14, respectively, held together by a narrow central portion 15. In the closed position, the upper float 13 abuts against the valve seat 6. A magnet is arranged on the underside of the lower float 14 and forms a first holding element 11. A second holding element 12 is fixedly arranged on the tube 3 in the lower end position and is made of a magnetic mate- rial. The first and the second holding elements 11, 12 together form a magnetic holding means 11, 12. The purpose of the valve device is to delay opening and closing of the inlet 4 during emptying and filling respectively. A conventional float follows the liquid level linearly, i.e. the position of the float depends merely on the liquid level in a container. However, the valve device is not opened by the float valve body 7 until the liquid level has fallen to a predetermined lower limit position 10 (Fig. 4) . The float valve body 7 of the valve device has in fact such great buoyancy that it is held in the closed position (Figs 2 and 3) as the liquid level falls, until the liquid level has reached the lower limit position 10 (Fig. 4). In continued emptying of the tube 3, the float valve body 7 falls to a lower end position (Figs 5-7), where it is held by the magnetic holding means 11, 12. As the liquid level again rises, the float valve body 7 is held by the holding means 11, 12 until a predetermined upper limit position 9 (Fig. 7) has been reached. In continued filling of the tube 3, the float valve body 7 is immediately moved to the closed position (Fig. 8) . Thus the position of the float valve body 7 depends on the one hand on the liquid level and, on the other hand, on whether the liquid level rises or falls . In the shown embodiment, the float valve body 7 falls from the lower limit position 10 to the lower end position (Fig. 5) in continued emptying of the tube 3. In Fig. 5, the float valve body has thus reached the lower end position at a liquid level which is lower than in Fig. 4. In Fig. 6, the tube has been filled up to the upper float 13, but the float valve body 7 is still held in the lower end position by the holding elements 11, 12. Without the holding elements, the float valve body 7 would already close the inlet 4 at the liquid level shown in Fig. 4, i.e. at the lower limit position 10. Due to the holding elements 11, 12, the float valve body 7 is held in the lower end position until the tube has been filled to the upper limit position 9 (Fig. 7), i.e. until the tube has been essentially filled. When the upper limit position 9 has been reached, the buoyancy of the float valve body 7 is greater than the mutual force of attrac- tion of the holding elements 11, 12, whereby the float valve body 7 rises. The dishwashing program of the dishwasher 2 comprises a washing phase, a pre-rinsing phase and a rinsing phase. During the washing phase and the pre-rinsing phase, dishwashing liquid and pre-rinsing liquid respectively are circulated in the dishwasher between the dishwashing compartment and the respective tank. During the dishwashing phase, dishwashing liquid is pumped from the dishwashing tank 18 to the dishwashing compartment 16 by means of the spray arms 17. Liquid that is sprayed into the dishwashing compartment 16 is collected by the collecting plate 21 and flows down into the dishwashing tank 18. The recirculation dishwashing tank 19 and its inlet 23 are filled with liquid during the dishwashing phase and the float valve body 7 closes the inlet 4 of the tube 3. Liquid collected by the collecting plate 21 thus cannot flow down in the tube 3. During the pre-rinsing phase, the pre-rinsing liquid is pumped from the recirculation rinsing tank 19 up to the dishwashing compartment 16 via the spray arms 17.

Consequently the liquid level in this tank 19 falls and, thus, also the liquid level in the inlet tube 3 falls, but this is initially held closed by the valve device 1 as explained above. Consequently, the first and, thus, dirtiest pre-rinsing liquid does not flow into the recirculation rinsing tank 19 through the inlet tube 3 but instead flows down into the dishwashing tank 18. When the liquid level in the recirculation rinsing tank 19 and in the inlet 3 has reached the lower limit position 10, the float valve body 7 falls. When the float valve body 7 has begun to fall, the valve device 1 is opened, which makes the pre-rinsing liquid, which is pumped from the recircu- lation rinsing tank 19 to the dishwashing compartment 16 and collected by the collecting plate 21, flow down in the inlet 4 of the tube 3 and again fill the recirculation rinsing tank. Of course, the float valve body 7 can also be designed as a single float or in some other manner, provided that it has the buoyancy required to produce the above-described delay function. It is possible to provide the float valve body 7 with a magnet also in its upper part and to make part of, or the entire, valve seat 6 of a magnetic material, adapted to be attracted by this magnet in order to produce a holding effect in cooperation with the buoyancy of the float valve body 7, so that the flat valve body is held in the closed position as the liquid level falls. The float valve body 7 can be arranged in a liquid tank instead of in a tube 3, in which case some kind of control is necessary for the float valve body to reach the closed position and the end position. For instance, the float valve body can be arranged on a spindle or in a cage . It is possible to provide delays of different lengths in opening and/or closing by changing the buoyancy of the float valve body and/or the force of the magnets. Even if the valve device has been described with reference to the inlet tube of a recirculation rinsing tank in a dishwasher, it will be appreciated that a valve device according to the invention can be used in other positions in a dishwasher or washing machine, for instance at an intake of dishwashing detergent or washing detergent, or for control of liquid flows in other contexts where a delayed opening and closing function is required.

Claims

1. A valve device (1), especially intended for a dishwasher (2) , said valve device comprising a liquid container (3) with an upper liquid inlet (4) and a lower liquid outlet (5) , a valve seat (6) which is arranged in the container (3) , and a float valve body (7) which is arranged in the container (3) and movable therein between an upper closed position, in which it abuts against the valve seat (6), and a lower end position, ch a r a c t e r i s e d in that the valve device (1) has a holding means (11, 12) which is arranged to hold the float valve body (7) in the lower end position as the liquid level rises, until the liquid level has reached an upper limit position (9), and the float valve body (7) has such great buoyancy that it is held in the closed position as the liquid level falls, until the liquid level has reached a lower limit position (10) .

2. A valve device as claimed in claim 1, in which the container (3) is an essentially vertical tube.

3. A valve device as claimed in claim 1 or 2, in which the holding means (11, 12) consists of a first holding element (11) which is arranged on the float valve body (7), and a second holding element (12) which is fixedly arranged on the container (3) and adapted to magnetically cooperate with the first holding element

(11) • 4. A valve device as claimed in claim 3, in which one holding element (11, 12) is a magnet and the other holding element (12, 11) is made of a magnetic material. 5. A valve device as claimed in claim 1 or 2, in which the holding means consists of a first holding element which is arranged on the float valve (7), and a second holding element which is fixedly arranged on the container (3) and adapted to mechanically cooperate with the first holding element. 6. A valve device as claimed in any one of claims 1-5, in which the float valve body (7) has an upper and a lower float (13 and 14 respectively) held together by a narrow central portion (15) . 7. A valve device as claimed in any one of claims 1-6, in which the float valve body (7) has an additional holding means which is arranged to hold the float valve body (7) in the closed position in cooperation with the same, until the liquid level has fallen to the lower limit position (10) . 8. A valve device as claimed in claim 7, in which the additional holding means consists of a third holding element which is arranged on the float valve body (7), and a fourth holding element which is fixedly arranged on the container (3) and adapted to magnetically cooperate with the third holding element.