EP1217936B1 - Water-bearing domestic appliance - Google Patents

Abstract

In a water-bearing household appliance with a liquid container filled through a valve in a liquid feed line, and in which a liquid filling level is detected for monitoring at least one safety level of a safety device, the safety device includes an optical light guidance system for reflecting a light beam by which the filling level is detected with the aid of a change in the reflection response on at least one reflecting site and is used to monitor the safety level. As an optical light guidance system, the safety device offers the advantage of dispensing with moving mechanical components-for example, a float, a level switch, an operating lever, an operating rod, etc.-to reduce the risk of mechanical defects that are associated with a substantial outlay on repair time and costs to a minimum or to completely eliminate the risk.

Description

The invention relates to a water-conducting household appliance with a container for liquid, which can be filled via a valve disposed in a fluid supply valve and in a level of the liquid for monitoring at least one safety level can be detected by a security device.

Water-bearing household appliances - for example dishwashers - are known a safety device for monitoring a safety level in a container filled with liquid. For this purpose, a detection of the level takes place the liquid. The container is arranged over a in a liquid supply line controllable valve filled. Thus, from the patent DE-C2-42 20 718 a water-leading Household appliance known whose safety device several containers having associated level sensor. These level sensors are arranged as one below the other Floats are designed to move one switch independently from each other can act on a switch rod. In this way, the detection takes place the level of pure mechanical, which requires a considerable amount of movable Components and thus an increased risk of mechanical defects means.

A water-conducting household appliance is also known from the patent GB-2 123 148-A.

It is an object of the present invention, a water-conducting household appliance of the beginning to improve the type mentioned.

This object is achieved according to the invention by the features of patent claim 1. Advantageous developments of the invention are specified in the subclaims.

Starting from a water-conducting household appliance with a container for liquid, which can be filled via a valve disposed in a fluid supply valve and in the one Liquid level for monitoring at least one safety level of one Safety device is detected, the object of the invention provides that the Safety device as an optical light guide system for reflecting a light beam is formed, by the level by means of a change in the reflection behavior detected at least one reflective point and to monitor the safety level is used.

The safety device designed according to the invention as an optical light guidance system offers the advantage that on moving mechanical components - such. Float, level switch, Shift lever, shift rod, etc. - can be dispensed with, so that the risk of Mechanical defects, associated with considerable effort in terms of repair time and costs are reduced to a minimum or completely eliminated. In addition, can be make the optical safety device easier and in water-bearing household appliances easier to mount than mechanical devices. The object of Invention supported by the optical light guide system advantageously also an electronic Evaluation of the recording and monitoring of one or more safety levels.

As low has been found according to a development of the invention that the detection the level to monitor a double safety level against a Trapping and emptying of the container is used. This can be done by the same Safety device - the optical light guide system - two safety levels simultaneously monitor safely and elegantly.

According to a favorable variant of the invention, the detection of the level is additional used for monitoring at least one predetermined filling level. This can be done also an individual filling level safe and elegant with one and the same safety device - monitor the optical light control system - in addition to the safety level. The separate collection and monitoring of the double security level and a filling level is by a single safety device with optical means possible.

Preferably, the optical light guide system comprises a dipstick and at least one prism-shaped reflection body for monitoring a double safety level on. Due to the reflection body, the light beam is particularly easy in the optical The light guide system is phased in and based on the reflection behavior on one or several places taking into account the different indices of refraction in the container of the household appliance existing liquid - preferably water - and the air used for recording the level for monitoring the safety level become.

Preferably, a prism body is arranged in the prism-shaped reflection body, from which the light beam is directed back into the dipstick and from there to the reflection body becomes. Thus, the path of the light beam for monitoring above all the double Security levels particularly simple and affect with little effort.

According to a preferred embodiment of the invention, the optical light guide system a prism-shaped reflection body for monitoring the filling level. In order to especially several reflection body for different monitoring purposes be advantageously arranged in one and the same light control system. To form a As compact as possible safety device is each prism-shaped reflection body firmly connected to the dipstick.

It is particularly favorable if an optical reflector is used on each prism-shaped reflection body Sensor for phasing the light beam into the light guide system and for phasing out the light Light beam is mounted from the light guide system. This is the initiation and Evaluate the security level (s) and reflection level fill level completely separate from each other. A mutual influence separates as good as off.

The optical light guide system is according to an advantageous further feature with an electronic Evaluation device - preferably processor-controlled - coupled, the at Receiving at least one monitoring signal from the light guide system at least one security measure initiated. The evaluation of incoming monitoring signals - z. B. through a microprocessor - from an optical system allows a smart direct Reaction of the household appliance to possible problems of the levels. Most have higher quality Home appliances anyway a processor control, so that for the above method not even an additional device necessary but only a software technical Adjustment of the existing processor control is performed.

From the evaluation device preferred options of security measures include switching off the valve and / or switching on a drain pump for pumping liquid from the container, or turning off the main switch of the Household appliance.

Fig 1

ein Prinzipschaubild der erfindungsgemäß ausgebildeten Sicherheitsvorrichtung zur Überwachung von Sicherheitsniveaus und Füllniveau, sowie

Fig 2

ein Funktionsschaltbild mit Einrichtungen zur Durchführung der Überwachung der Niveaus bei Verwendung des optischen Lichtleitsystems als Sicherheitsvorrichtung.

The invention will be explained in more detail with reference to an embodiment shown in FIGS. In detail show:

Fig. 1

a schematic diagram of the inventively designed safety device for monitoring safety levels and filling level, and

Fig. 2

a functional diagram with means for performing the monitoring of the levels when using the optical light guide system as a safety device.

Fig. 1 shows a schematic diagram of a security device 1, not in one shown water-conducting household appliance -. B. a dishwasher - arranged is. The dishwasher has a container for liquid - preferably Water - on, as a rinse tank usually via a in a liquid supply line located controllable valve is filled, see, for. B. the arrangement according to DE 42 20,718 C2. In this case, the liquid flows out of the liquid supply line when the filling valve is open into the container. The safety device 1 according to the invention allows by optical means to monitor a level of security that overfills the Container with the liquid avoids, and preferably in addition a second level of security, that the emptying of the container -. B. by a leak at the bottom of Container - prevented. In addition to monitoring the double safety level causes the safety device 1 also the detection of the level in addition to monitoring at least one predetermined fill level.

The security device 1 is in accordance with the subject invention as optical Light guide system - preferably made of permeable material such. As plastic or Plexiglas - educated. It has a preferably tapering on the ground dipstick 2 in Cylindrical shape and a prism-shaped reflection body 3 for monitoring the double Security levels and a prism-shaped reflection body 4 for monitoring a predetermined filling level. Both reflection body 3, 4 are with the Dipstick 2 firmly connected and arranged one below the other in the present example. Of the a prism-shaped reflection body 3 is located at the upper end of the dipstick 2, while the other prism-shaped reflection body 4 is parallel at a short distance is located underneath.

Due to the dipstick-like shape, the safety device 1 in the liquid of the Rinsing container, for example, immersed as a conventional Füllanzeigestift in the vertical direction become. The light guide system is at several points of contact with the container connected, for example, by the tip of the dipstick 2 at the bottom of the container and by the triangular ends of the reflection body 3, 4 on a container wall.

To monitor the double security level, a light beam 5 - is preferred Infrared beam - the reflection body 3 and fed through the prism shape at several Positions 7, 8 are reflected so that it is arranged on a reflection body 3 in the prism body 3 ', from which the incoming light beam is directed into the dipstick 2. This deflected light beam runs in a vertical direction to the bottom of the dipstick 2, is reflected there at points 9, 10 and directed to the prism body 3 'back. The prism body 3 'then deflects the reflected light beam 5' in such a way that it the reflection body 3 in the opposite direction of the supplied light beam 5 again leaves. To phase in the light beam 5 in the light guide system and to phase out the reflected light beam 5 'from the light guide system is on the prism-shaped reflection body 3 - preferably on its back - an optical sensor 13 attached. The optical sensor 13 consists for example of a photodiode for transmitting the Light beam 5 and a phototransistor for receiving the light beam 5 '. The A- and Ausphasung the infrared beam is at least approximately in the horizontal direction.

Taking into account the different refractive indices of air and water based the detection of the level on the reflection of the supplied light beam 5 in optical light guide system. In its contact with the water at one of the reflective Positions 7, 8, the reflection behavior in the reflection body 3 and the changes Light beam is interrupted, for example. Thus, the upper reflection body monitors 3, which is arranged approximately at the level of the maximum permitted in the container level, the Security level against overcrowding. A coupled with the light control system electronic Evaluation device - see Fig. 2 with description - receives one from the sensor 13th triggered monitoring signal and evaluates it. If the light beam has been interrupted, the evaluation device recognizes the error and initiates at least one safety measure, which reliably prevents overfilling of the container.

In a corresponding manner, the upper reflection body 3 monitors the safety level in addition to emptying - for example, due to leakage of the container on Soil - due to the different refractive indices of air and water the reflection behavior at one of the reflecting points 9, 10 at the bottom of Dipstick 2 changes and the light beam is interrupted again. The change of the Reflectance behavior leads in the sensor 13 to trigger a monitoring signal, the the electronic evaluation device is transmitted for evaluation.

For additional monitoring of a certain filling level, a light beam 6 - also preferably an infrared beam - the reflection body 4 and fed through the Prism form at several points 11, 12 reflected so that it the reflection body. 4 leaves in the opposite direction of the supplied light beam 6 again. To the Einphasen the light beam 6 in the light guide system and to phase out the reflected Light beam 6 'from the light guide system is on the prism-shaped reflection body 4 - preferably on its rear side - also an optical sensor 14 attached. Of the For example, the optical sensor 14 has a photodiode for transmitting the light beam 6 and a phototransistor for receiving the light beam 6 '. The injection and phasing out The infrared beam is at least approximately in the horizontal direction. The capture the fill level and the individual filling level to be monitored is in turn based on the principle of reflection of the supplied light beam 6 in the optical light guide system taking into account the refractive indices of water and air. At a contact of the reflection body 4 with the water at one of the reflecting points 11, 12 changes the reflection behavior in the reflection body 4 and the infrared beam is interrupted. Thus monitors the lower reflection body 4, which is approximately equal to that in the container to be monitored level is arranged on the dipstick 2, the individual Filling level. The coupled with the light control system electronic evaluation device Upon interruption of the light beam receives a triggered by the sensor 14 monitoring signal and evaluate it. Does the evaluation recognizes the achievement of the desired Filling levels, it causes at least a security measure that the avoid further filling of the container. The double security level and the predefinable Füllniveau can by one and the same safety device according to the invention an optical light guide system is advantageously monitored separately from each other. Mechanical components and the associated defects are eliminated.

Fig. 2 shows a basic functional diagram with means for carrying out the Monitoring the safety levels and, if necessary, the filling level when using the optical The light guide system of FIG. 1 as a safety device in the water-bearing Household appliance. The devices include a function generator FG, an electronic Sensor SS, an evaluation AU and a microprocessor PU, the Control signals for components of the household appliance - in the present example of the dishwasher - As valve V for filling the washing container, drain pump U for pumping the liquid from the container and a main switch H to turn on and off of the household appliance. The function generator FG generates a clocked input signal and fed to the downstream sensor SS, which according to the comments to 1 has a photodiode on the input side and a phototransistor on the output side. Receives the sensor SS downstream evaluation device AU from the phototransistor a signal corresponding to the phased input signal, it recognizes that no Change in the reflection behavior in the light guide system is present and thus no Monitoring signal was generated. Evaluation device AU and function generator FG preferably together form an electronic circuit for level monitoring. If, however, the sensor SS delivers a signal deviating from the input signal, the signal is taken Evaluation device AU on this signal as a monitoring signal and generates a control signal for the microprocessor PU for triggering at least one security measure. The double safety level is via the one electronic sensor on the reflection body of the optical light guide system, which has a corresponding output signal while checking the filling level, the electronic sensor checks at the other reflection body of the optical light guide system a corresponding Output signal for evaluation and reaction provides. Preferred security measure insist on detecting one or the other security level in that the microprocessor PU in the presence of the corresponding control signal, the Close valve V to stop further filling of the washing and thus counteract the overfilling, or turn off the main switch H to the avoid further filling and thus the defect of a component -. B. Leakage of Bottom tank - display. A safety measure when detecting the filling level consists in turning on the drain pump U, which sucks liquid from the container.

In the event that you want to capture and monitor multiple filling levels, you can several optical light guide systems of dip rods with associated reflection bodies be arranged in the container. The electronic evaluation is done in the same way and As described above with reference to the functional diagram.

Claims (13)

1. Water-conducting domestic appliance with a container for liquid, which can be filled by way of a valve arranged in a liquid feed duct and in which a filling state of the liquid is detectable by a safety device (1) for monitoring at least one safety level, wherein the safety device (1) is constructed as an optical waveguide system for reflection of a light beam (5), by which the filling state is detected by way of change in the reflection behaviour at at least one reflective location (7, 8) and used for monitoring the safety level, characterised in that the detection of the filling state is used for monitoring a double safety level relative to an overflowing and an emptying of the container.
2. Water-conducting domestic appliance according to claim 1, characterised in that the detection of the filling state is additionally utilised for monitoring at least one predeterminable filling level.
3. Water-conducting domestic appliance according to claim 1 or 2, characterised in that the optical waveguide system comprises an immersion rod (2) as well as at least one prismatic reflection body (3, 4) for monitoring a double safety level.
4. Water-conducting domestic appliance according to claim 3, characterised in that a prismatic body (3'), by which the light beam (5) is guided into the immersion rod (2) and from there back to the reflection body (3), is arranged in the prismatic reflection body (3).
5. Water-conducting domestic appliance according to claim 3 or 4, characterised in that the optical waveguide system comprises a prismatic reflection body (4) for monitoring the filling level.
6. Water-conducting domestic appliance according to one of claims 3 to 5, characterised in that each prismatic reflection body (3, 4) is fixedly connected with the immersion rod (2).
7. Water-conducting domestic appliance according to one of claims 3 to 6, characterised in that an optical sensor (13, 14) for phasing the light beam (5, 6) into the waveguide system and for phasing the light beam (5', 6') out of the waveguide system is mounted at each prismatic reflection body (3, 4).
8. Water-conducting domestic appliance according to one of the preceding claims, characterised in that the waveguide system is coupled with an electronic evaluating device (AU) which on reception of at least one monitoring signal from the waveguide system initiates at least one safety measure.
9. Water-conducting domestic appliance according to claim 8, characterised in that the safety measure consists of switching off the valve (V).
10. Water-conducting domestic appliance according to claim 8 or 9, characterised in that the safety measure consists of switching off a solution pump (U) serving for sucking liquid out of the container.
11. Water-conducting domestic appliance according to claim 8, characterised in that the safety measure consists of switching off the main switch (H) of the domestic appliance.
12. Water-conducting domestic appliance according to one of the preceding claims, characterised in that the waveguide system consists of transparent material.
13. Water-conducting domestic appliance according to one of the preceding claims, characterised in that the waveguide system is connected with the container at several contact points.

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