DIFF Subgroup
F22B 21/28 bent spirally
Introduced: September 1968
Full Title
Water-tube boilers of vertical or steeply-inclined type, i.e. the water-tube sets being arranged vertically or substantially vertically > built-up from water tubes of form other than straight or substantially straight > bent spirally
No child classifications to compare. This is a leaf node in both IPC and CPC.