Abstract:
A vent cap ( 10 ) for a battery having a centrally disposed cavity ( 22 ) to militate against contamination of battery components from impurities contained in the ambient air and also including a plurality of alternating partitions ( 26 ) which creates a condensation medium for the deposit of droplets of electrolyte carried by gases venting from the battery.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims the benefit of U.S. provisional patent application Serial No. 60/212,763, filed Jun. 20, 2000. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The invention relates to a vent cap and more particularly to a vent cap for a battery including a labyrinth structure through which gas from the battery is caused to pass while droplets of electrolyte carried by the gases from the battery are caused to condense and coalesce on the labyrinth structure.  
         BACKGROUND OF THE INVENTION  
         [0003]    Wet cell electric storage batteries such as those used in industrial traction batteries typically include a battery cover having a vent opening providing communication with a battery cell. The vent opening facilitates access to the battery cell for initial filling with electrolyte and permitting the fluid level to be checked and corrected occasionally during the life of the battery. The vent opening also permits the controlled venting of gases generated during the discharging and the recharging of the battery.  
           [0004]    Prior art battery vent caps incorporate a vertical flow configuration for directing venting gases from a battery. An inherent problem with the vertical flow configuration is the possibility of contamination of the battery fluid with foreign matter such as oil, neutralizing agents used in washing the battery, or other substances which could settle on the vent cap surfaces. Additionally, the contaminants can restrict or block the gas vent. A restricted or blocked gas vent can result in a dangerous pressure buildup within the battery cell or element jar creating the possibility of a ruptured cell or cover separation.  
           [0005]    Other problems inherent in prior art vent cap designs include the loss of electrolyte from the battery in the vent gas and the use of structures having numerous parts.  
           [0006]    It would be desirable to produce a vent cap which militates against entry of contaminants into an associated battery, militates against loss of electrolyte from the battery, and minimizes vertical gas flow from the battery.  
         SUMMARY OF THE INVENTION  
         [0007]    Consistent and consonant with the present invention, a vent cap for a battery cell cover which militates against entry of contaminants into an associated battery, militates against loss of electrolyte from the battery, and minimizes vertical gas flow from the battery has surprisingly been discovered. The vent cap for a battery cell cover having an aperture formed therein comprises: a main body having a centrally disposed cavity, the main body including an inlet and an outlet, the inlet providing communication between an associated battery cell and the cavity and the outlet providing communication between the cavity and ambient air, and a plurality of spaced apart partitions defining a flow path, the partitions disposed in the cavity of the main body. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    The above, as well as other objects, features, and advantages of the present invention will be understood from the detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings, in which:  
         [0009]    [0009]FIG. 1 is a bottom perspective view of a vent cap incorporating the features of the invention;  
         [0010]    [0010]FIG. 2 is a bottom perspective view of an alternate embodiment of the vent cap illustrated in FIG. 1; and  
         [0011]    [0011]FIG. 3 is a perspective view of the vent cap illustrated in FIG. 1 showing the vent cap installed in the open position on an associated battery cell cover.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0012]    Referring now to the drawings, and particularly FIGS. 1 and 3, there is shown generally at  10  a vent cap incorporating the features of the invention. The vent cap  10  includes an annular main body  12 . The main body  12  has an annular outer wall with a first lower surface  14  and a cooperating second upper surface  15 . An annular lip  16  extends outwardly from the first surface  14 . The second surface  15  has a generally cylindrical head portion  18  which extends outwardly therefrom, as illustrated in FIG. 3. A plurality of spaced apart protuberances  20  are formed on an outer wall of the head portion  18 .  
         [0013]    The main body  12  includes a centrally disposed cavity  22  formed by an inner cylindrical wall  24  of the main body  12 . A plurality of alternating partitions  26  form a flow path in the cavity  22  for vent gases from an associated battery. Each of the partitions  26  includes a plurality of spaced apart baffles  28  which cooperate to form a labyrinth to maximize the overall length of the flow path through the partitions  26 . In the embodiment shown, the baffles  28  of one partition  26  are interdigitated between the baffles  28  of an adjacent partition  26 . The partitions  26  and baffles  28  provide a large surface area for condensation of conderisables such as electrolytes, for example, present in the vent gases from the battery. It is understood that the partitions  26  can either be formed separately and inserted into the cavity  22  or integrally formed with the main body  12 .  
         [0014]    An inlet  30  is formed in the inner cylindrical wall  24  and provides fluid communication between a cell of the battery and the cavity  22 . An outwardly and laterally extending lift tab  32  is formed adjacent an outlet  34 . The outlet  34  is formed in the head portion  18  of the main body  12  and provides fluid communication between the cavity  22  and the ambient air. A hydrophobic barrier  36  is disposed within the cavity  22  to cover the outlet  34 . A pair of spaced apart guide walls  37  are adapted to receive, position, and hold the hydrophobic barrier  36  in place against the inner cylindrical wall  24 . The hydrophobic barrier  36  is produced from any conventional material antagonistic to water such as sintered polypropylene, for example. Although a planar hydrophobic barrier  36  is illustrated, it is understood that a barrier having a different shape can be used such as curved to conform to the inner cylindrical wall  24 , for example. A removable cover  38  is adapted to enclose the cavity  22 , while leaving the inlet  30  open as illustrated in FIGS. 1 and 3.  
         [0015]    A hinge section or platform  40  extends outwardly and laterally from the main body  12  diametrically opposite the lift tab  32  and includes a pair of oppositely extending protuberances  42  and  43 . The protuberances  42  and  43  are adapted to be received with respective upwardly projecting pin receiving detents  44  and  45  typically formed integral with a battery cell cover  48 . The protuberances  42 ,  43  and the respective detents  44 ,  45  cooperate to form a hinge between the vent cap  10  and the battery cell cover  48 . It is understood that other hinges can be used.  
         [0016]    In operation, the vent cap  10  is installed on the battery cell cover  48  by snapping the protuberances  42 ,  43  into the slots formed on the respective detents  44 ,  45 . The vent cap  10  is pivoted about the protuberances  42 ,  43  until the lip  16  of the main body  12  is received in an aperture  50  formed in the battery cell cover  48 .  
         [0017]    The vent cap  10  functions to condense electrolyte from gases being vented from the battery. The vent gases enter the inlet  30  and are directed through the flow path in the labyrinth formed by the partitions  26  and baffles  28 . The large amount of surface area created by the unique labyrinth provides an efficient condensing surface which causes electrolyte droplets to condense out of the vent gases and drain back into the battery, thereby minimizing required electrolyte balancing. The removal of the electrolyte from the vent gases also helps keep the top surfaces of the battery clean and eliminates dangerous and irritating fumes. Other liquid and solid contaminants present in the vent gases will also be removed. The vent gas then travels through the hydrophobic barrier  36  and out of the vent cap  10  through the outlet  34 .  
         [0018]    The outlet  34  is located directly below and protected by the lift tab  32 . The outlet  34  is thus protected by the lift tab  32  against contamination and foreign matter present on the top of the battery.  
         [0019]    The entire vent cap  10  may be opened to permit easy inspection of water levels by grasping the lift tab  32  and pulling upward and pivoting the vent cap  10  about the protuberances  42 ,  43 . A watering device such as a hose, for example, may be easily inserted into the battery for filling. Prior art vent caps require that the watering device be directed through the vent cap assembly when filling the battery cells which is often difficult and hinders visual observation of the water level within the battery. After inspection or filling of the battery cell, the vent cap  10  is pivoted to be reinserted in the aperture  50  of the battery cell cover  48 .  
         [0020]    Additionally, the unique labyrinth structure of the present invention provides flame and spark protections. The structure serves as a flame and spark arrestor and militates against ignition of fumes which escape from the battery by sparks or flames.  
         [0021]    A second embodiment of the present invention is illustrated in FIG. 2, wherein prime numerals are utilized to describe parts which are the same as illustrated in FIGS. 1 and 3. The hydrophobic barrier  36 ′ of the second embodiment is disposed within the cavity  22 ′ to cover the inlet  30 ′.  
         [0022]    From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various usages and conditions.