| 摘要 |
Venting equipment comprising a housing (119) containing a main valve (51) opening upwardly to control gaseous and/or vaporous medium flow into the housing and a secondary valve (117) controlling medium flow out of the housing has the main and secondary valves counterbalanced to move in opposite directions relative to their respective valve seats by a linkage (116) within the housing, the linkage being arranged so that the secondary valve moves at a faster rate than the main valve. |
