Chemistry: electrical current producing apparatus – product – and – Having specified venting – feeding or circulation structure – Venting structure
Reissue Patent
2000-11-01
2002-11-05
Kalafut, Stephen (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
Having specified venting, feeding or circulation structure
Venting structure
C429S082000, C429S087000, C429S088000, C429S071000, C429S072000, C429S175000, C429S163000, C429S225000, C429S176000
Reissue Patent
active
RE037901
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The invention relates to a storage battery cover, and more particularly to a storage battery cover offering added protection against leakage when a battery using the cover of the invention is tipped to any one of its sides or inverted.
(2) Description of the Prior Art
Conventional storage batteries include a battery housing having a housing and a cover for closing an open top end of the casing. The battery housing is a rectangular casing having multiple compartments or cells for receiving cell plates and electrolyte therein. The cover device is heat sealed to an open top end of the battery housing casing.
The cover device often includes a main cover part and a sub-cover part. The main cover part has a horizontally disposed plate body with a top face formed by a rectangular confining wall. The confining wall is divided by multiple partitions and associated chambers. The main cover further includes multiple service ports for pouring electrolyte into respective cell compartments within the casing and multiple degassing vents and drain-back return holes associated with each cell.
The sub-cover is integrally secured to the main cover after electrolyte has been poured into the cell compartments through the service ports. The sub-cover part is heat sealed to the main cover part along its perimeter and at top edges of the partitions and chamber walls. The chambers and partitions ultimately form enclosed chambers and associated paths from the cell vent and return hole of each cell to multiple atmospheric vents. The chambers typically include relatively large containment areas for holding electrolyte spilled into the battery cover when the battery is tipped.
In operation, heat that is generated during electrolysis causes the electrolyte and water in the electrolyte to evaporate. This evaporation is referred to as “gassing”. Gassing of the cells occurs at any point the battery reaches the hydrogen over-voltage, producing bubbles that break at the surface introducing a mist into the venting gas stream. In conventional batteries, the vaporized electrolyte was released to atmosphere through an atmospheric vent in the cover device. Loss of electrolyte through the atmospheric vent requires replenishing electrolyte in the battery housing periodically. In order to overcome electrolyte loss, a battery housing with a cover capable of recovering the vaporized electrolyte was developed, thereby obviating the need for replenishing the electrolyte in the battery housing.
When the electrolyte in the cell compartments undergo electrolysis and evaporates due to the heat that is generated, the vaporized electrolyte flows into the path formed in the cover through the cell vents or drain-back holes. Since the interior of the cover is exposed to the atmosphere via the atmospheric vent, the interior temperature of the cover is less than that of the vaporized electrolyte entering the cover. Thus, heat transfer occurs so that the vaporized electrolyte condenses, and the resulting condensate flows back into the corresponding cell compartments via the drain-back holes. The paths are often sloped towards the drain-back holes to further facilitate the return of electrolyte to the respective cells. Since the vaporized electrolyte is recovered instead of released to atmosphere, there is no need to periodically replenish the electrolyte in the battery housing.
Although these batteries prevent electrolyte loss during normal operation, the battery will leak, and in many cases pour, electrolyte from the atmospheric vents when the battery is tipped to one side, inverted or agitated. Batteries are often placed in a non-upright position during shipping, handling or accidents, such as car wrecks. A significant threat to person and property arises when electrolyte leaks from a battery.
Various approaches have been taken in the past to deal with the problem of electrolyte spilling or leaking from a battery when it is tipped to any one of its sides. Many of the arrangements are acceptable in situations where the battery is tilted to its side and not subjected to vibration or other forms of movement. However, the related art has yet provided a cost effective battery cover providing total steady state leak protection when the battery is tipped to one side and substantial resistance to electrolyte leakage when subjected to vibration, agitation or inversion.
U.S. Pat. No. 1,605,820 to Edwards discloses a multilevel chamber configuration for each cell. The chamber includes two opposed inclined partitions for preventing electrolyte spills when the battery is tipped to one side. The chamber configuration provides no inverted leak protection. Furthermore, the large chamber configuration provides very limited protection against vibration or agitation when tipped to one side.
U.S. Pat. No. 3,597,280 to Hennen disclosed a multiple vent plug assembly for merely reducing spillage when a battery is partially tipped or completely inverted. The plug assembly incorporates a multi-chamber configuration designed to contain a substantial portion of electrolyte prior to spilling the electrolyte to atmosphere. The Hennen patent does not disclose a chamberless cover design or provide substantial leak protection over extended periods of time.
U.S. Pat. No. 4,348,466 to Elehew et al. discloses a large rectangular chamber configuration having an inlet in communication with a respective cell. Each chamber has an outlet off to one side of and below the inlet. A passage associated with the chamber outlet is provided for containing and holding electrolyte. The passage has an outlet in communication with an atmospheric vent. The arrangement is such that the chambers and associated passages are of sufficient volume to retain the amount of electrolyte displaced into them when equilibrium is achieved between levels of electrolyte in the cells and respective chambers and passages.
The Elehew et al. patent requires that a portion of the passage be above the chamber inlet regardless to which side the battery is tipped. When the chambers and the passages fill with electrolyte, an airlock is developed which prevents additional flow of electrolyte from the cell into the chamber and passage configuration.
The Elehew et al. patent provides no leak protection when the battery is inverted and provides only steady state protection when the battery is tipped to one side. As seen from viewing the chamber and passage configuration of the Elehew et al. patent, when a battery using the Elehew et al. cover is tipped on various sides and vibrated or agitated, it is very likely that electrolyte will spill out of the chamber and run into the passage to the venting area. The large chambers and passage configuration in Elehew et al. allows substantial amounts of electrolyte to spill into the battery cover; thus, increasing the likelihood of electrolyte being spilled into the venting area and ultimately leaking outside the battery systems. The Elehew et al. patent is directed towards preventing leak protection at a steady-state equilibrium when the battery is tipped to one side. Having substantial amounts of electrolyte in the cover and limited flow restriction substantially increases the likelihood that electrolyte will spill if the battery is vibrated or agitated after arriving at an equilibrium in a non-upright position.
Similar configurations are shown in U.S. Pat. No. 5,380,604 to Hampe et al. and U.S. Pat. No. 5,424,146 to Lin. Both patents disclosed leak resistant battery covers having chambers associated with each cell. The chambers have guides for controlling the flow of acid. However, each cover is designed to allow a significant amount of electrolyte to flow into the respective cover and provides no protection against electrolyte leakage when the battery is inverted and very limited protection when vibrated or agitated.
The German Patent No. 4,216,563 discloses a dual section cover having a chamber associated with each cell. Each chamber is sized so that when the battery is tipped or inverted, no more acid from a res
Fritts Robert W.
Revak David M.
Douglass Battery Manufacturing Company
Kalafut Stephen
Martin Angela J.
Womble Carlyle Sandridge & Rice PLLC
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