| 422 / | HD | CHEMICAL APPARATUS AND PROCESS DISINFECTING, DEODORIZING, PRESERVING, OR STERILIZING |
| 129 | DF | CHEMICAL REACTOR {28} |
| 168 | DF | .~ Waste gas purifier {5} |
| 169 | DF | .~.~ Including means providing sequential purification stages {1} |
| 170 | | .~.~.~ Plural chemical reaction stages {2} |
| 171 | DF | .~.~.~.~> Solid, extended surface, fluid contact type |
| 172 | DF | .~.~.~.~> And means downstream of a stage for injecting a reactant into waste gas for interreaction in subsequent stage |