| 165 / | HD | HEAT EXCHANGE |
| DIG 9 | DD | HAVING A SOLID HEAT STORAGE MASS FOR ABSORBING HEAT FROM ONE FLUID AND RELEASING IT TO ANOTHER (I.E. REGENERATOR) {5} |
| DIG 37 | DD | .~ Having flow diverting means (e.g. valve) to selectively control flow through storage mass {2} |
| DIG 41 | | .~.~ Rotary diverting means |