{ }. (Gas Manuf.) A compound hydraulic valve for regulating the passage of the gas through a set of purifiers so as to cut out each one in turn for the renewal of the lime. [ Webster 1913 Suppl. ]

{ or }. (Gas Manuf.) A compound hydraulic valve for regulating the passage of the gas through a set of purifiers so as to cut out each one in turn for the renewal of the lime. [ Webster 1913 Suppl. ]