| 165 / | HD | HEAT EXCHANGE |
| DIG 184 | DD | INDIRECT-CONTACT CONDENSER {12} |
| DIG 217 | DD | .~ Space for coolant surrounds space for vapor {4} |
| DIG 221 | DD | .~.~ Vapor is the only confined fluid {1} |
| DIG 222 | | .~.~.~ Plural parallel tubes confining vapor connecting between spaced headers |