| 165 / | HD | HEAT EXCHANGE |
| DIG 454 | DD | HAVING SIDE-BY-SIDE CONDUITS STRUCTURE OR CONDUIT SECTION {16} |
| DIG 459 | | .~ Strips with shaped, interfitted edges form heat exchanger core with plural passages {1} |
| DIG 460 | DD | .~.~> With spacers interposed between adjacent passages |