Liquid container with electrical level monitoring

Abstract

A liquid container with electrical fill level monitoring, with at least one fill level sensor (9) arranged therein with electrodes (10, 11) for measuring an electrical variable and with an evaluation unit connected to the electrodes (10, 11), wherein the electrodes (10, 11) project into the interior of the container and can be connected to the evaluation unit on the outside of the container, wherein the electrodes (10, 11) are arranged separately in the wall of the liquid container (6) in a sealing manner in the region of a plug receptacle (12) formed on the outside of the container and are formed on the outside of the container to form plug contacts (13), characterized in that the arrangement of the electrodes (10, 11) in the wall of the liquid container (6) is carried out after injection molding by screwing in or by hot shooting into the same.

Description

The invention relates to a liquid container with an electrical fill level monitoring device, in particular a washing liquid container for a windscreen wiper system and / or a headlight cleaning system on a vehicle according to the preamble of claim 1.Window cleaning systems and / or headlight cleaning systems on a vehicle usually have a liquid container with a control device for its fill level. This control device can consist of a level limit switch with a float which interacts with a control lamp arranged in the cockpit and activates the latter when a predetermined minimum level is undershot. To detect a plurality of filling levels in a liquid container, a plurality of detection means, for example reed contacts, arranged one above the other can be arranged, with which a float interacts, as is described in DE 198 33 464 A1. The float carries a magnet and follows the liquid level. If the position of the magnet corresponds to one of the reed contacts, an electrical signal is triggered by the latter and is fed to a display device connected via a connector socket.In a fill level display device described in DE 198 56 174 A1, the fill level is determined by means of a conductivity measurement. For this purpose, the fill level sensor has a plurality of contact plates enclosed in the wall of the liquid container and is connected to an evaluation device via a connection socket.The subject matter of DE 91 03 858 U1 is an electrical fill level measuring arrangement with a measuring rod in which an electrical line is arranged and is provided with a plug for electrical connection. To simplify the construction and installation of the measuring rod, the plug is integrated into the measuring rod and is cast on it in a non-detachable and sealing manner. This results in a reduction in parts, and the measuring rod can easily be arranged in a liquid container, in particular a window washer of a vehicle, and connected to the electrical overall system.DE 100 53 592 A1 describes a fill level sensor which consists of two individual sensors, each of which is formed from a pair of electrodes and which measure the same electrical variable, for example current, conductance or resistance, and feed it to an evaluation unit, the two pairs of electrodes being extended over a partial height in the container. From the measured values, which are compared with zero, with one another or with reference values stored in the evaluation unit, conclusions can be drawn as to how far each of the two sensors is immersed in the liquid. The fill level sensor is preferably sealingly fastened as a component in the opening of a container wall or inserted into such a wall. However, the electrode pairs can also be arranged as two separate structural units and combined by an interconnection to form a fill level sensor.In practice, it is also known to use only one electrode pair combined to form a component as fill level sensor for detecting a fill level. The component formed has a mounting base holding the electrodes for arrangement in the container wall and is formed on the container exterior as a plug connector, wherein the electrodes are formed into plug contacts in the formed plug connector housing. This component is sealingly secured with the mounting base by means of a rubber bushing as sealing means in an opening in the container wall, for example in the lower region of one of the container walls for detecting a lower fill level limit value. This construction and fastening arrangement entail high parts costs and increased assembly effort.DE 196 27 082 A1 discloses a liquid container of the generic type having an electrical fill level monitoring system which has a fill level sensor with electrodes for measuring an electrical variable. In contrast to the injection during the injection process, the electrodes are pressed into bores provided in the upper shell of the liquid container after the injection part has cooled.DE 38 27 744 A1 discloses a method for producing a device for monitoring the liquid level in a container. For this purpose, electrodes of a liquid sensor are placed in a blow mold in such a way that they do not penetrate the container wall of the liquid container. The electrodes are then driven through the container wall of the liquid container.It is the object of the invention to design a liquid container with an electrical fill level monitoring according to the preamble of claim 1 in a cost-reduced manner.This object is achieved in a liquid container having the features of claim 1. Advantageous embodiments are listed in the dependent claims.The invention consists in that, in the case of a liquid container having an electrical fill level monitoring device, which has at least one fill level sensor arranged therein and having electrodes for measuring an electrical variable and an evaluation unit connected to the electrodes, and the electrodes project into the container interior and can be connected on the container exterior side to the evaluation unit, the electrodes are arranged separately in the container wall in a sealing manner in the region of a plug receptacle formed integrally on the container exterior side and are formed on the container exterior side into plug contacts. This eliminates the complicated preliminary production and preliminary assembly of a level sensor or fill level sensor provided with a mounting base, which is designed as a preliminary assembly unit on the container exterior side to form a plug receptacle and must moreover be arranged in a sealing manner in the container wall by means of a rubber bushing. The plug receptacle is formed on the housing wall, namely during the production of the liquid container by injection molding.According to the invention, the electrodes are subsequently arranged in such an integrally formed plug receptacle, namely by screwing into the container wall or by hot injection into the latter. Depending on the design of the fill level monitoring system, i.e. depending on a plurality of fill levels to be displayed, a plurality of fill level sensors designed in this way can be arranged one above the other and connected to an evaluation unit.A comparative example not encompassed by the invention is described below: FIG. 1 : a fill level sensor according to the prior art for arrangement in a washer fluid container of a windscreen wiper system in a vehicle, FIG. 2 : a washing liquid container with an integrally formed plug receptacle and injection-molded electrodes, FIG. 3 : this plug receptacle, enlarged, and FIG. 4 : shows the electrode arrangement in a horizontal section.FIG. 1 shows a pair of electrodes formed as a fill level sensor. This has a mounting base 3 which holds the electrodes 1 and 2 for arrangement in an opening in the wall of a washing liquid container in a vehicle, the electrodes of the installed fill level sensor projecting into the interior of the washing liquid container. The mounting base 3 is sealingly secured in an opening formed in the container wall by means of a rubber spout 5 of known type. On the outside of the container, the fill level sensor or the mounting base 3 is designed as a plug connector 4 for connection to an evaluation unit.Compared to this prior art, FIG. 2 shows a liquid container 6 produced by injection molding, to which a liquid pump 7 is fastened, having fastening means 8 for fastening in the vehicle and having an integrated fill level sensor 9, the latter being formed by two electrodes 10, 11 arranged fixedly in the wall of the liquid container 6 and a plug receptacle 12 formed integrally on the container outer side for connection to an evaluation unit, not shown. The electrodes 10 and 11 project into the liquid container 6 and are formed in the region of the plug receptacle 12 into flat plug contacts 13. The plug receptacle 12 is enlarged in FIG. 3 and is also shown in a horizontal section in FIG. 4. The sealing arrangement of the electrodes 10 and 11 and the formation of the plug receptacle 12 is effected by injection molding for producing the liquid container 6.List of reference characters1 Electrode 2 Electrode 3 Holder base 4 Plug connector 5 Rubber grommet 6 Liquid container 7 Liquid pump 8 Fastener 9 Level sensor 10 Electrode 11 Electrode 12 Plug receptacle

Claims

Liquid container having an electrical fill level monitoring device, having at least one fill level sensor (9) arranged therein, having electrodes (10, 11) for measuring an electrical variable, and having an evaluation unit connected to the electrodes (10, 11), wherein the electrodes (10, 11) project into the container interior and can be connected to the evaluation unit on the container exterior side, wherein the electrodes (10, 11) are arranged separately in a sealing manner in the wall of the liquid container (6) in the region of a plug receptacle (12) formed integrally on the container exterior side and are formed on the container exterior side into plug contacts (13), characterized in that the electrodes (10, 11) are arranged in the wall of the liquid container (6) after the injection molding by screwing in or by hot shooting into the same.Liquid container according to claim 1, characterised in that a plurality of filling level sensors (9) are arranged one above the other in the wall of the liquid container (6).

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