Swedish Patent and Registration Office
IPC Maintenance Project M 747, subclass F23M
January 18th, 2013
Rapporteur Report
Background
The reason for starting this project was that it was realised that F23M contains groups, such
as F23M 3/04, F23M 9/02 and F23M 9/04, that relate to air feeding, which is covered by
F23L. Formally, since F23M is a residual subclass, these groups should be empty. It was
decided to investigate the problems during a definition project (D 273), but since changes to
the scheme were deemed necessary IPC/WG/28 decided to start this maintenance project
for the purpose of making the necessary changes.
Rapporteur's opinion
In our opinion the main groups of F23M, with exception of 99/00, are not residual places. We
think main groups F23M 3/00 – F23M 11/00, which each cover more or less well-defined
constructional details of combustion apparatus, operate in the same way in relation to other
subclasses of F23 as the other detail subclasses (F23H – F23L, F23N and F23Q). For
example, we think the relationship between F23M 7/00 (Doors) and F23B or F23C is the
same kind of "details versus whole things" relationship as that between F23K (fuel feeders)
and F23B or F23C. See this table:
F23M 3/00
F23M 5/00
F23M 7/00
F23M 9/00
Firebridges (baffles not
confining the fire
F23M 9/06)
Casings; Linings; Walls
(casings, linings, or walls of
heat-treatment chambers of
ovens, kilns, or retorts
F27D)
Doors specially adapted
for combustion chambers
(in general E06B; for flues
or smoke-boxes
F23J 13/08)
Baffles or deflectors for
air or combustion
products; Flame shields
F23M 11/00 Safety arrangements (by
controlling combustion
F23N 5/24)
F23M 99/00 Subject matter not
provided for in other
groups of this subclass
Not a residual place. There are no related
places in F23.
Not a residual place. Some specially adapted
matter is classified in F23R, but that is no
contradiction and no limiting references are
needed.
Not a residual place. There is some overlap with
F23L that should be cleared up with a group
definition.
Not a residual place, but baffles or deflectors
structurally associated with burners should be
classified in F23D, so limiting references are
needed.
It could perhaps be argued that this is a residual
place, since there are several other places for
safety arrangements in places in F23
(F23D 5/16, F23D 14/72, F23G 5/50, F23K 5/16,
F23N 5/24, F23Q 7/24, F23Q 25/00). However,
we think references are a better solution.
Obviously a residual place.
Areas of conflict between F23M and F23L (and F23C):
 Firebridges with means for feeding air or steam: A limiting reference to F23M 3/04
must be added at subclass level in F23L.




Heating combustion air by air-cooling combustion chamber walls: No reference
needed, classify in both F23L 15/00 and F23M 5/08.
Doors specially adapted for air feeding: No reference needed, classify in both
F23L and F23M 7/00.
Baffles or deflectors in air inlets: We think F23M 9/02 is misplaced and superfluous
and should be deleted. The matter is covered by F23C 7/00, F23L 1/00 and F23L
9/00. If the group is retained limiting references are needed from F23C 7/00 and
F23L. However, we note that in CPC the matter is partly covered by F23C 7/004, and
therefore the IPC backfile is partly covered by F23C 7/00, so the situation is not
crystal-clear.
Baffles or shields with air-supply passages: Limiting references are needed in
F23C 7/00 and F23L.
For the detailed proposal see the accompanying Annex 3.
Anders Bruun