The cap includes a transverse top wall which is spaced from {TAIL ~ the top edge} of the inner wall to provide an overflow path for surges of {HEAD ~ liquid} and gas 
The cap includes a transverse top wall which is spaced from { TAIL ~ the top edge } of the inner wall to provide an overflow path for surges of { HEAD ~ liquid } and gas
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH