Chemistry: electrical current producing apparatus – product – and – Having specified venting – feeding or circulation structure – Venting structure
Reexamination Certificate
2001-06-14
2004-06-08
Kalafut, Stephen J. (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
Having specified venting, feeding or circulation structure
Venting structure
C429S089000
Reexamination Certificate
active
06746795
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to battery caps for insertion into fill ports of a lead-acid storage battery, particularly deep cycle, high charge and high discharge batteries of the type utilized on golf carts and other battery powered vehicles.
2. Description of the Prior Art
A typical lead-acid battery consists of a plurality of cells filled with aqueous sulfuric acid electrolyte. The cells employ negative plates using lead as the electroactive material and positive plates in which lead oxide is the electroactive material. Sets of an equal number of positive and negative plates in the electrolyte are referred to as cells. Each lead-acid cell produces two volts per cell. The assembly of several cells in a series circuit to produce a higher voltage is called a battery.
Each cell in a battery has a fill opening which requires a battery cap. The purpose of the fill opening is to provide an opening for electrolyte filling and water replacement. The fill opening also provides a path to vent gas that is produced during charging and discharging of the battery.
The purpose of the battery cap is to prevent the electrolyte from spilling or spewing from the battery cells. The sulfuric acid battery electrolyte is highly caustic and can cause injury to persons upon contact, eat holes in clothing and other fabric materials, and rapidly corrode metal if it is ejected from the battery. Therefore, it is highly desirable to prevent electrolyte from escaping the battery case. During charging a battery generates bubbles within the acid that can and do spew electrolyte from the battery unless precautions are taken. Conventional prior art battery caps are therefore equipped with splash guards, baffles and other devices designed to recover and return to the battery cells electrolyte spewed from the battery.
Lead-acid cell batteries have intrinsic hazards. It is well known that lead-acid storage batteries utilized on motor vehicles emit potentially explosive gases during charging and discharging. During the normal course of charging and discharging a battery, a potentially explosive mixture of oxygen and hydrogen is liberated. A conventional battery cap is not a solid structure, but is typically hollow and includes one or more passageways to vent the mixture of oxygen and hydrogen from the battery compartment to the atmosphere at a slow rate. This process is referred to as off-gassing.
An inherent danger that accompanies the off gassing process is the possibility that a spark, flash or flame might enter the battery cell through the vent passageway of a battery cap. If this occurs the volatile, explosive gases are ignited within the battery, whereupon the battery will explode. If this happens acid and battery fragments are thrown through the air. When this occurs damage to the battery compartment is very likely, and the risk of personal injury is quite great.
Because of the risk of personal injury and property damage that may occur, original equipment manufacturers (OEM's) and battery distributors have insisted in recent years that battery caps utilized on batteries with which they deal must be APF (flame retardant approved). This is achieved by utilizing a microporous disc as a flame barrier in each battery cap. This microporous disc acts as a spark or flame arrester.
One problem created by porous disc spark arresters is the “loading” or destruction of the porosity of the microporous filter from suspended particulate contamination carried by the gas bubbles during off gassing. Such contaminants do not pass through the microporous filter but are instead loaded into the open pores of the porous disc. As a result of this process the porosity of the filter disc is reduced from its design specifications. As this occurs internal battery gas pressure rises. As pressure increases above and beyond atmospheric pressure, battery acid is spewed through a conventional battery cap and into a battery compartment. This results in a loss of electrolyte which, when it escapes the battery, is likely to cause injury or damage.
Also, the buildup of gas pressure within a battery alters the “battery envelope”. That is, gas pressure buildup within a battery alters the outside dimensions of the battery. The battery bulges and can damage the battery compartment. Also, unless pressure is relieved the battery can crack and leak electrolyte.
In the past battery caps have been designed to attempt to solve these problems. In some cases the porous disc is protected by splash guards. Examples of battery caps constructed in this way are described, for example, in U.S. Pat. Nos. 5,422,199; 5,209,992; 4,400,450; and 5,132,175. Also, some battery caps have been designed with labyrinth paths. Examples of these types of battery caps are found in U.S. Pat. Nos. 5,132,175; 5,209,992; and 5,422,199. In other battery caps special types of chambers have been constructed. Examples of these appear in U.S. Pat. Nos. 4,400,450; 5,132,175 and 5,422,199.
Some conventional battery caps perform satisfactorily when utilized on relatively shallow cycle batteries of the type employed for ignition in a gasoline or diesel fuel powered vehicle. However, until the present invention battery caps employing microporous disc spark or flame arresters have not been feasible for use with the high charge and high discharge batteries required as the sole power source for vehicles such as golf carts, warehouse forklifts and other such vehicles. Some of the deep cycle batteries suitable for such vehicles are sold with the trade designations 250's, L16's, J185's, and Scrubbers.
The introduction of the widespread requirement for spark and flame arresters has created a new set of problems in lead-acid electrical storage batteries. One of these problems is the interruption of the natural equilibrium of the internal gas pressure within a battery cell and the outside atmosphere. This imbalance in equilibrium is made progressively worse by the deterioration of the porous disc spark or flame arrester. This deterioration results from the agglomeration of particulate contaminants in the porous disc that are carried in the aqueous electrolyte solution.
During the usual charging and discharging cycle of a battery the negative lead plates and positive lead oxide plates of the battery gradually erode. Particles from the heavy-metal plates are carried into the aqueous sulfuric acid electrolyte as dissolved, particulate matter. These particles eventually precipitate to the bottom of the battery. This byproduct is called “mud” in the battery industry.
During agitation and jostling of the battery that occurs as a battery powered vehicle travels, the particles of “mud” are carried into suspension in the electrolyte. These particles are ultimately transported to the microporous flame arrester by gas bubbles created in the electrolyte during charging and discharging and by spewing electrolyte.
SUMMARY OF THE INVENTION
One important object of the present invention is to provide a battery cap which does incorporate a spark or flame arrester for used in a deep charge, lead-acid electrical storage battery of the type used to power golf carts, forklifts and similar vehicles.
A related object of the invention is to provide a battery cap that solves the problem of pressure buildup and envelope expansion in deep cycle lead-acid electrical storage batteries.
In one broad aspect the present invention may be considered to be a battery cap for insertion into a fill port of a cell of a lead-acid electrical storage battery comprising a hollow, tubular body, a diverter located within the tubular body, a flame arrester located within the tubular body above the diverter, and a top end closure.
The tubular body is a hollow, barrel shaped body having upper and lower ends. It is formed with an upright, annular wall having an exterior configured to engage a battery fill port. The wall has a first snap fit engaging element on its inner surface at the upper end of the body. The upper end of the body defines a circular mouth opening. An an
Kalafut Stephen J.
Thomas Charles H.
LandOfFree
Lead-acid safety battery cap does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Lead-acid safety battery cap, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Lead-acid safety battery cap will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3334838