GB2082773A

GB2082773A - Liquid Level Indication

Info

Publication number: GB2082773A
Application number: GB8025517A
Authority: GB
Original assignee: Chloride Group Ltd
Current assignee: Chloride Group Ltd
Priority date: 1980-08-05
Filing date: 1980-08-05
Publication date: 1982-03-10

Abstract

An electrolyte level detector for an electric storage battery consists of a conduit (11) sealed at (12) into the lid (13) of the battery casing with the lower end at a predetermined minimum electrolyte level and the upper end opening into an external glass chamber (14) or an external bellows which can be used to give an indication of the electrolyte level. The battery is filled at reduced pressure so that when the liquid covers the bottom of conduit (11) chamber 14 is at reduced pressure. When filling is complete pressure in space 16 rises to atmospheric and liquid is drawn up into the chamber. If the bottom of the conduit (11) is uncovered the liquid drains away. <IMAGE>

Description

SPECIFICATION Electrolyte-level Detector This invention relates to an electrolyte level detector for use with an electric storage battery, and one object is to provide a means for indicating whether the electrolyte level is above or below a predetermined minimum level, in a battery arranged to be filled by the type of suction filling operation described in British Patent Specification No. 79.34782. In such a method of filling a battery or a number of batteries, electrolyte is drawn by a downstream pump through the battery casings in series from an electrolyte reservoir and during the filling operation the pressure in the battery casing will be a little below atmospheric pressure.

According to the present invention, an electrolyte level detector for use with an electric storage battery to be filled with electrolyte under reduced pressure, comprises a conduit sealed into the casing of the battery to extend below the minimum electrolyte level and communicating with an external closed chamber having means for indicating whether the pressure in the chamber is or is not below atmospheric pressure.

At the beginning of the filling operation when the pump is started, the pressure in the casing will be below atmospheric pressure, and so will the pressure in the closed chamber; as filling proceeds and the electrolyte level arises above the lower end of the conduit, the volume within the conduit and the closed chamber will be sealed off, and will remain below atmospheric pressure so that after filling has been completed and the pump is switched off, and the pressure in the top of the casing increases to atmospheric pressure, some electrolyte will be forced up through the conduit into the closed chamber. The closed chamber can be transparent walled, or have a window in it, through which the electrolyte level can be seen.As long as electrolyte is in the closed chamber, it will be known that the electrolyte level in the casing has not dropped below the lower end of the conduit, so that the battery does not require refilling. Once the electrolyte level drops below the minimum level, and the bottom of the conduit communicates with the atmospheric pressure in the top of the casing, the electrolyte in the closed chamber will drop back into the battery casing.

In another embodiment, the top of the conduit is arranged to be closed by a valve carried by one wall of a flexible bellows defining the external closed chamber. During filling, the suction will contract the bellows and close the top of the conduit, but when the electrolyte level drops below the minimum level, and the pressure within the conduit returns to atmospheric pressure, the resilience of the bellows will restore it to its normal raise position. Thus, by observing whether the bellows is raised or lowered, the operator can decide if the level is above or below the minimum level.

The invention may be carried into practice in various ways, and two embodiment will be briefly described by way of example as applied to a battery, whose casing is shown at 10 for filling by the method described in British Patent No.

79.34782. Reference will be made to the accompanying drawings, each figure of which is a sketch of a different form of electrolyte level detector.

A conduit 11 is sealed with an epoxy resin 12 into the lid 1 3 of the battery casing. The lower end of the conduit is at the predetermined minimum electrolyte level, and the upper end opens into an external sealed glass chamber 14 in Figure 1.

During filling, when the level is below the minimum level 15, and the space 1 6 in the top of the casing is below atmospheric pressure, the space within the conduit 11 and chamber 14 will also be perhaps 2.5 p.s.i. below atmospheric pressure, and when during filling the liquid level rises and closes the lower end of the conduit at the moment shown in the Figure, that space will be sealed off and will remain at the reduced pressure. When filling is complete to the maximum level 17, and the filling pump is switched off, the pressure in the top of the casing at 1 6 will be restored to atmospheric pressure and that will drive some electrolyte up the conduit 11 and into the chamber 14 where it can be seen through the glass wall.As long as electrolyte can be seen, it is clear that the level within the casing is above the minimum level 15, but as soon as the level drops below that minimum level, the electrolyte will drop out of the chamber 14 into the casing and the operator can see that refilling is required In the alternative arrangement shown in Figure 2 the closed chamber is defined by a resilient bellows 18, the top wall of which carries a valve plate 1 9 which closes the top of the conduit 11 when the bellows is contracted and the top moves downwards. That happens during filling when the space within the conduit and the chamber is below atmospheric pressure.The pressure remains below atmospheric pressure and the valve plate 1 9 remains held down over the top of the conduit as long as the electrolyte level is above the minimum level 15, but as soon as it drops below the minimum level, the pressure in the conduit rises, and the resilience of the bellows raises the top wall and the valve plate 1 9 again, so that the operator can see whether the electrolyte level is below or above the minimum level in dependence on whether the top of the bellows is held down or is released to its upper position. The force tending to release the bellows from its down position might be about 2 inches water gauge.

The bellows might give a false indication due to a leakage in the level detector, but the operator can always test for that by pushing the top of the bellows down and seeing if it remains down showing that the pressure within the conduit is still below atmospheric pressure, and the electrolyte level has not dropped.

The device might be screwed into the lid of the battery container, instead of being sealed in with a resin.

Claims

1. An electrolyte level detector for use with an electric storage battery to be filled with electrolyte under reduced pressure comprising a conduit sealed into the casing of the battery to extend below the minimum electrolyte level, and communicating with an external closed chamber having means for indicating whether the pressure in the chamber is or is not below atmospheric pressure.

2. A detector as claimed in Claim 1 in which the closed chamber is transparent walled or has a window in it for seeing the electrolyte level.

3. A detector as claimed in either of the preceding claims in which the top of the conduit is arranged to be closed by a valve carried by one wall of a flexible bellows defining the external closed chamber.

4. An electrolyte level detector constructed and arranged substantialiy as herein specifically described with reference to Figure 1 or Figure 2 of the accompanying drawings.

5. An electric storage battery having sealed into its lid an electrolyte level detector as claimed in any of the preceding claims.