pipe segment 51 may be used for liquid product fill service and the pipe segments connected to the downward oriented ports of valves 25 and 39 fig3 which extend via any desired piping configuration into upper region 59 of tank 3 may be used for vapor withdrawal service valve 49 typically is fixed in place by virtue of pipe segment 51 which is welded or flanged to the valve and to bottom cover 21 of valve box 53 bottom cover 21 may be connected to the internal structure of tank 3 by means of bolts 61 to ring 63 which is part of cylindrical side wall 19 as earlier described an appropriate gasket not shown may be installed between bottom wall 21 and ring 33 side wall 19 is joined to top wall 67 of tank 3 via flange section 15 and threaded bolt holes 17 are disposed in flange section 15 as earlier described valve box 53 can be sealed by attaching top cover 7 to flange section 15 with a gasket between not shown and installing threaded bolts 13 into threaded bolt holes 17 when sealed valve box 53 encloses the valves pipe segments and sealable closures described above thus valve box 53 when sealed serves three purposes u2014 it.