Project TE 117, Existing Example No. A15
Level/Categories
CL 1a, 1b, 2b1, 3a, 3b
AL 1a, 1b, 2b1, 2b3, 3a, 3b
Documents (Classification is Based on US 4 013 760 A)
US 4 013 760 A
FR 2 239 739 A1
DE 23 38 739 B1
Short Version of the Disclosure
Graphite or carbon molded articles of high isotropy and high heat conductivity, especially
useful for high temperature reactor fuel elements, are prepared by pressing a mixture of a
binder and a powdery carbon filler which consists partially or wholly of pyrolytically
produced isotropic carbon with subsequent heat treatment of the pressed article. There is used
as the filler an isotropic pyrolytic carbon made by depositing a hydrocarbon on a carbon
granulate and then grinding to a particle size of less than 100 micrometers.
Representative Prior Art
Nuclear fuel elements produced from mixtures containing carbon or graphite based particles
and a binder are well known:
- a compacted mixture of finely divided graphite and pyrolitic carbon coated nuclear fuel
particles is impregnated with a carbonisable substance (see US 3406227 - the basic document
of the present example - claim 1).
- as filler a carbon black obtained by thermal pyrolysis of gaseous hydrocarbon can be used
(see US 4013760, col. 1, lines 48-51)
Invention Information
I1: Process for producing isotropic carbon particles comprising pyrolysing hydrocarbon gas
on isotropic carbon granulates to form a carbon deposit on the granulates and grinding to a
carbon powder having a particle size below 100 micrometers (see claim 1).
I2: The particles obtained in I1 are used to produce molded synthetic carbon articles by
mixing them with a resin as binder and carbonizing the resin (see col. 1, lines 5-10 and col. 4
lines 14-25).
I3: The articles obtained in I2 are suitable for use in high temperature reactor fuel elements
(see col. 1, lines 5-10)
[Classification is based on US 4 013 760. In this document only I1 is claimed. So strictly,
what is defined above as I2 and I3 could be considered as additional information. From the
whole description in the document however, it is clear that the purpose of the invention is to
ameliorate the characteristics of the nuclear fuel elements, not so much to produce a new kind
of carbon particles. Therefore, it is considered to be more correct to characterize these two
pieces of information as invention information rather than as additional information.]
Additional Information
No additional information found.
Identification of Potential Subclasses
Subject Matter
Tool
Query
IPC Places
I1
Catchword Index
CARBON
C01B
I2
IPCCAT
Invention information description (I2)
C04B
I3
Catchword Index
NUCLEAR reactors
G21C
Analysis and Selection of Classification Symbols
Core Level
I1: Class C01 relates to inorganic chemistry, i.e. to the chemical elements and their
compounds as well as their preparation. Subclass C01B deals with non- metallic elements.
The IPC definitions of groups of chemical elements can be found in the note after the title of
section C. In the whole class C01, as well as in subclass C01B itself, the last place priority
rule applies. From the subclass index (as from the search in the Catchword Index) it is clear
that carbon is classified in main group C01B 31/00.
I2: Articles made of carbon are generally considered to be ceramic products. That is why
IPPCAT (as well as the catchword index) points to C04B, and more particularly to C04B
35/00 the main group relating to shaped ceramic products and their composition. In this part
of IPC, classification of a composition is made according to the constituent present in the
highest proportion by weight (see note (1) after the title of C04B 35/00. In the present
example only carbon (or graphite which is a special form of carbon) is present, thus this rule
does not apply. The common rule brings us to C04B 35/52, the group for ceramic products or
compositions based on carbon, e.g. graphite.
I3: The subclass index for G21C leads to main group G21C3/00 for reactor fuel elements and
the selection of substances therefore. In this subclass the common rule applies. Selection of
substances is classified in G21C 3/42.
The same subclass index points to main group G21C 21/00 for processes specially adapted to
the manufacture of reactors or parts thereof. In the basic document (see col.4, line 51 - col.5,
line 10) a process for manufacturing composite nuclear reactor fuel elements that include fuel
containing and fuel free zones is described. So further classification is made in this group.
What is claimed in the patent document under consideration, is the production of the isotropic
carbon particles. Therefore, classification symbol C01B31/00 should be listed first as this
symbol thus most adequately represents the invention.
Advanced Level
I1: Class C01 relates to inorganic chemistry, i.e. to the chemical elements and their
compounds as well as their preparation. Subclass C01B deals with non- metallic elements.
The IPC definitions of groups of chemical elements can be found in the note after the title of
section C. In the whole class C01, as well as in subclass C01B itself, the last place priority
rule applies. From the subclass index (as from the search in the Catchword Index) it is clear
that carbon is classified within main group C01B 31/00. While in the art of nuclear fuels,
graphite is the common material used, the document to be classified refers both to carbon and
graphite. Therefore classification is made both in C01B 31/04 (graphite) and C01B 31/02
(carbon). As graphite is the more traditional material used in the art, symbol C01B 31/04 is
put first.
I2: Articles made of carbon are generally considered to be ceramic products. That is why
IPPCAT (as well as the catchword index) points to C04B, and more particularly to C04B
35/00 the main group relating to shaped ceramic products and their composition. In this part
of IPC, classification of a composition is made according to the constituent present in the
highest proportion by weight (see note (1) after the title of C04B 35/00. In the present
example only carbon (or graphite which is a special form of carbon) is present, thus this rule
does not apply. The common rule brings us to C04B 35/52, the group for ceramic products or
compositions based on carbon, e.g. graphite. Because a carbonisable binder is used, the most
appropriate subgroup is C04B 35/532.
I3: The subclass index for G21C leads to main group G21C 3/00 for reactor fuel elements and
the selection of substances therefor. In this subclass the common rule applies. Selection of
substances is classified in G21C3/42 and its subgroups. The subgroup relating to ceramics is
G21C 3/62.
The same subclass index points to main group G21C 21/00 for processes specially adapted to
the manufacture of reactors or parts thereof. In the basic document (see col.4, line 51 - col.5,
line 10) a process for manufacturing composite nuclear reactor fuel elements that include fuel
containing and fuel free zones is described. The common rule applied in this subclass leads us
thus to G21C 21/02.
What is claimed in the patent document under consideration, is the production of the isotropic
carbon particles. Therefore, the classification symbols of C01B should be listed first as this
subclass thus most adequately represents the invention.
Subject
Matter
Analysis of Subclass
Selection
Subclass
Analysis of Group Selection
IPC CL
IPC (2006)
IPC AL
C01B31/00
C01B31/04
(2006.01)
C01B31/02
(2006.01)
I1
Subclass title covers
subject matter
C01B
Last place priority rule
I2
Subclass title covers
subject matter
C04B
Common rule
C04B35/52
I3
Subclass title covers
subject matter
Common rule
G21C3/42
G21C21/00
Complete Classification
G21C
C04B35/53
2
(2006.01)
G2C3/62
(2006.01)
G21C21/02
(2006.01)
The complete core and advanced level classification for this document based on the above
analysis is as follows:
Core Level
Int. Cl. (2006)
C01B 31/00
C04B 35/52
G21C 3/42
G21C 21/00
Advanced Level
Int.Cl.
C01B 31/04 (2006.01)
C01B 31/02 (2006.01)
C04B 35/532 (2006.01)
G21C 3/62 (2006.01)
G21C 21/02 (2006.01)