Battery water-refill plug

This application is the US-national stage of PCT application PCT/EP2016/000273 filed 18 Feb. 2016 and claiming the priority of German patent application 102015012175.8 itself filed 23 Sep. 2015.

The invention relates to a water-refill plug for automatically filling and refilling cells of a battery and comprising a valve body that is actuated by a float and closes the valve when the battery cell is full in order to end the refilling.

During the electrical charging of batteries, water is electrolyzed during charging. In order not to reduce the service life and performance of the battery, water must therefore be refilled regularly into the battery cells. This is often achieved by means of water-refill plugs plugged into the fill opening of the battery cover and connected in series with the aid of conduits. These water-refill plugs close automatically when the fill level in the battery cells has reached the desired point. The fill level in the cells is often determined with the aid of floats. The movement of the float is transferred to the valve body via a rod assembly, so that the valve closes when the desired fill level has been reached, as is known from WO 83/00260 [U.S. Pat. No. 4,512,378].

As a result of the charging and discharging processes, impurities form in the battery cells that float on the electrolyte surface and deposit on the parts of the refilling plugs that come into contact with the electrolyte. This can lead to sticking of the rod assembly and thus to the malfunctioning of the refilling plug.

A water-refill plug is known from DE 35391671 where the upper head of the float forms the valve body and, in its upper position, seals the valve seat. A retaining element projects upward on the head of the float body, rests with a ferromagnetic part against a permanent magnet, and is held thereby in this position. Detachment is achieved by means of a pressure pulse transmitted through the refill conduit.

It is the object of the invention to provide a water-refill plug with a simple construction that ensures reliable functionality even in case of contamination of the electrolyte.

According to the invention, this object is achieved in that a permanent magnetic force is exerted between the valve body and the float so that movement of the float is transferred to the valve body.

In this solution, no rod assembly is necessary between valve body (or valve control element) and float, so sticking or blockage cannot occur even in case of contamination of the electrolyte, thus ensuring reliable functionality over extended periods.

It is advantageous that valve body and float are not mechanically connected to one another.

An especially simple construction with a high level of functional reliability is achieved if a permanent magnet is provided on or in the float, with the magnets being fastened so as to be poled such that they repel each other, so that lifting of the float results in lifting of the valve body into its closed position.

One advantageous alternative solution consists in providing a permanent magnet or a part made of ferromagnetic material on or in the valve body and a permanent magnet on or in the float, the latter moving the valve body through its attractive force.

Another advantageous alternative solution consists in providing a permanent magnet or a part made of ferromagnetic material on or in the float and a permanent magnet on or in the valve body, the latter being moved by the float through the magnetic attractive force.

Preferably, the permanent magnet and/or the part made of ferromagnetic material are annular. The valve body is held securely in its closed position if the valve body is by the force of the flowing water toward its closed position.

Embodiments of the invention are illustrated in the drawings and described in further detail below.

FIG. 1 shows a vertical axial section through a first embodiment of the water-refill plug, and

FIG. 2 shows a vertical axial section through a second embodiment of the water-refill plug.

The water-refill plug 1 has a substantially cylindrical housing 15 that is plugged into the opening of a battery cover above a battery cell. A gasket ring 10 in an annular groove on the outside of the housing seals the plug in the fill opening of the battery cover. A T-connector 7 is plugged with an O-ring 8 into the upper side of the plug 1 to which water hoses are plugged and through which distilled water is conducted via the T-piece 7 to the inside of the plug.

A float housing 16 is fastened to the underside of the housing 15 that forms a basket 12 with a floor 13 for a float body 11 that can move vertically by the electrolyte from the lower position shown in FIG. 1 into an upper position. A first permanent magnet 6 is fastened in or on the upper end of the float body 11 .

The float housing 16 is formed at its upper end with an upwardly projecting guide collar 17 that is upwardly open and in which a lower thickened end of a vertically displaceable valve body 4 rests, with a lower large-diameter end forming the closing part 4 a of the valve body 4 . The collar 17 guides the closing part 4 a for vertical movement upward until the closing part 4 a reaches and blocks a valve seat 14 that is formed by an inner conduit 9 of the housing 15 . A valve body rod 4 b extends vertically upward from the closing part 4 a on whose upper end a member 3 sits that is guided in a downwardly open guide recess 2 of an upper part 18 of the housing 15 .

A second permanent magnet 5 in the closing part 4 a of the valve body 4 is vertically above the first permanent magnet 6 . If water is refilled into the battery cell via the T-piece 7 and via the plug 1 , the float 11 rises with its magnet 6 . Since the mutually facing poles of the two magnets 5 , 6 have the same polarity, the two magnets repel each other and the float magnet 6 presses the closing part 5 upward until the valve of the parts 4 and 14 is closed and the flow of water is stopped.

The embodiment shown in FIG. 2 differs from the first inter alia in that only one permanent magnet 5 is present, which acts with attractive force on a part ferromagnetic material. Here again, the lifting of the float 11 brings about the lifting of the valve body 4 . FIG. 2 shows that the permanent magnet 5 is on the closing part 4 a and the part 6 made of ferromagnetic material is on the float 11 . Instead, however, the permanent magnet can also be fastened to the float and the part made of ferromagnetic material can be fastened to the closing part. In both embodiments, the magnetic attractive force is exploited so as to move the valve body 4 upward using the float 11 in order to close the valve with a sufficiently high liquid level of the electrolyte.

The permanent magnet and/or the part made of ferromagnetic material can be annular, so that of these parts can fit through the other of the parts. Distilled water flowing through the valve 4 , 14 can also be guided such that the valve body ( 4 ) is urged by the flowing force of the flowing water toward its closed position and held securely.