Nonspill vented closure assembly for storage battery

Abstract

A nonspill vented closure assembly is provided for a wet cell type of storage battery which normally provides a venting hole to the interior of the battery, and which includes a tiltable weight that lifts a valve to close the vent hole whenever the battery is tilted with respect to the vertical beyond a certain angular displacement, so as to prevent leakage of the liquid electrolyte through the closure assembly. The closure assembly includes a tubular casing which is threaded into the normal fill hole of the battery. A lead weight which constitutes the tiltable mass is supported in the casing. A valve stem connects the lead weight to a valve member, and it serves to move the valve member against an annular valve seat surrounding an orifice in the lower end of the casing whenever the lead weight is tilted. The valve stem includes a ball at its upper end which extends into a cavity in the bottom of the lead weight, and which is held in the cavity by a plastic disc which forms a bearing surface for the ball. A cover is mounted on the other end of the casing, and a vent hole extends through the cover. A hydrophobic porous filter is mounted under the cover, and this filter forms a secondary barrier for preventing any liquid electrolyte from leaking through the vent. The casing is provided with an internal sloping shelf which supports the lead weight, the shelf having internal channels which serve as drainage means to permit and facilitate the free flow back into the interior of the battery of any liquid electrolyte in the closure assembly.