| 422 / | HD | CHEMICAL APPARATUS AND PROCESS DISINFECTING, DEODORIZING, PRESERVING, OR STERILIZING |
| 129 | DF | CHEMICAL REACTOR {28} |
| 168 | DF | .~ Waste gas purifier {5} |
| 173 | DF | .~.~ With heat exchanger for reaction chamber or reactants located therein {2} |
| 174 | | .~.~.~ Electrical type |