| 165 / | HD | HEAT EXCHANGE |
| DIG 327 | DD | THERMOSYPHONIC HAVING VERTICAL AIR DRAFT PASSAGE {3} |
| DIG 337 | DD | .~ Heating or cooling means entirely surrounded by air draft passage forming casing {3} |
| DIG 341 | | .~.~ Parallel heating or cooling tubes or tubular sections (e.g., coil, serpentine, etc.) |