Liquid indicator for a storage battery with a flame barrier vent filter

Claim 1

A LIQUID LEVEL INDICATOR HAVING AN ELONGATED ROD OF LIGHT TRANSMITTING MATERIAL HAVING AN UPPER VIEWING SURFACE AND A LOWER REFLECTING SURFACE, A CAP HAVING A THROUGH BORE ADAPTED TO ACCEPT THE UPPER END OF SAID ROD, AN ANNULAR CHAMBER IN SAID CAP WHICH IS SPACED FROM AND SURROUNDS THE BORE AND THE ROD, SAID CHAMBER BEING OPEN AT ITS UPPER END TO AMBIENT CONDITIONS AND AT ITS CLOSED END BEING PROVIDED WITH AT LEAST ONE PORT WHICH IS IN COMMUNICATION WITH THE INTERIOR OF THE CONTAINER BEING MONITORED, A POROUS FLAME BARRIER FILTER POSITIONED WITHIN AND CLOSING THE UPPER OPEN END OF SAID CHAMBER, SAID ROD FURTHER HAVING A RELATIVELY LARGE DIAMETER LATERALLY EXTENDING RIM AROUND SAID ROD AND IN ENGAGEMENT WITH THE PERIPHERAL INNER CAP WALL FORMING THE LOWER PORTION OF THE BORE OF SAID CAP AND HAVING AT LEAST ONE POINT OF DISCONTINUITY AT THE JUNCTURE OF SAID RIM AND SAID WALL, AND A RELTIVELY SMALL DIAMETER RIM AROUND SAID ROD WHICH IS POSITIONED ABOVE SAID LARGE DIAMETER RIM AND SPACED FROM SAID WALL, A RESILIENT EALING LIP POSITIONED WITHIN SAID BORE OF SAID CAP AND ADAPTED TO ENGAGED SAID SMALLER DIAMETER RIM TO SEAL THE BORE WITHIN WHICH SAID ROD IS POSITIONED, SAID LARGE DIAMETER RIM AND SAID WALL AT THEIR POINT OF DISCONTINUITY CREATING A PORT MEANS FORMING A GAS PASSAGEWAY TO THEREBY PERMIT THE PASSAGE OF GAS UPWARDLY THERETHROUGH WHILE SAID SMALL DIAMETER RIM FORMS A PROJECTING BAFFLE IN ALIGNMENT WITH SAID GAS PASSAGEWAY, SAID CAP BEING FORMED OF A RESILIENT MATERIAL SUCH THAT WHEN SAID CAP IS AXIALLY TELESCOPED WITH THE UPPER END OF SAID ROD, THE NATURAL RESILIENCY OF SAID CAP FORMS A COMPRESSION FIT WITH SAID FILTER AND SAID ROD SO AS TO MAINTAIN SAID ROD AND FILTER IN PLACEE IN SAID CAP