| 165 / | HD | HEAT EXCHANGE |
| DIG 51 | DD | HAVING EXPANSION AND CONTRACTION RELIEVING OR ABSORBING MEANS {2} |
| DIG 52 | DD | .~ For cylindrical heat exchanger {6} |
| DIG 60 | | .~.~ Expandable casing for cylindrical heat exchanger {2} |
| DIG 61 | DD | .~.~.~> For plural cylindrical heat exchangers |
| DIG 62 | DD | .~.~.~> Having particular external casing support means |