being equal in arms 64 and 66 as depicted in fig2 when battery gases are discharged from cell 12b into manifold 10 or when gases are vented through the manifold to above cell 12b the gas pressure builds up in tube 44b and thus in chamber 52 the gas buildup forces water 70 from trap 58 into chamber 50 remote from cell 12b as seen in fig3 because of the difference in diameters the flow of water 70 into chamber 50 reduces the water head blocking the gases when the gas pressure is sufficient to overcome the water head a burst of gases flow through the trap into chamber 50 and thus into tube 44a water displaced from trap 58 by the burst splashes into chamber 50 but is not carried through the chamber because of its relatively large size the gas escape reduces the pressure in chamber 52 and the water drains into trap 58 to reestablish the seal when an explosion is ignited in manifold 10 adjacent cell 12b the resulting increase in gas pressure temporarily brakes the liquid seal in flame arrestor 48 however the water 70 has sufficient inertia to quench the flame prior to releasing the gases thus flame arrestor 48 prevents the explosion from spreading while safely venting gases to reduce the damage to cell 12b most probably the water physically blocks the flame from reaching the explosive gases in chamber 50 it is believed that the gas release through the seal and water drainage to reestablish the seal occur concurrently as a result the gases in chambers 50 and 52 are never in direct communication.