Top IPC subclasses
|
1
|
F03D
|
47
|
Wind motors
|
|
2
|
F24J
|
21
|
Production or use of heat not otherwise provided for
|
|
3
|
H02M
|
21
|
apparatus for conversion between ac and ac, between ac and dc, or between dc and dc, and for use wit
|
|
4
|
C25B
|
21
|
Electrolytic or electrophoretic processes for the production of compounds or non- metals; apparatus therefor
|
|
5
|
G09B
|
17
|
educational or demonstration appliancesappliances for teaching, or communicating with, the blind, de
|
|
6
|
H02J
|
13
|
circuit arrangements or systems for supplying or distributing electric powersystems for storing elec
|
|
7
|
H01F
|
12
|
magnetsinductancestransformersselection of materials for their magnetic properties
|
|
8
|
A01G
|
12
|
Horticulture; cultivation of vegetables, flowers, rice, fruit, vines, hops, or seaweed; forestry; watering
|
|
9
|
F24S
|
10
|
|
|
10
|
H05B
|
9
|
electric heatingelectric lighting not otherwise provided for
|
|
11
|
C02F
|
8
|
Treatment of water, waste water, sewage, or sludge
|
|
12
|
H01L
|
8
|
Semiconductor devices; electric solid state devices not otherwise provided for
|
|
13
|
F23D
|
6
|
burners
|
|
14
|
B01D
|
4
|
Separation
|
|
15
|
E02D
|
4
|
foundationsexcavationsembankmentsunderground or underwater structures
|
|
16
|
C25C
|
4
|
processes for the electrolytic production, recovery or refining of metalsapparatus therefor
|
|
17
|
H01M
|
4
|
processes or means, e.g. batteries, for the direct conversion of chemical energy into electrical ene
|
|
18
|
F24H
|
3
|
fluid heaters, e.g. water or air heaters, having heat-generating means, in general
|
|
19
|
G01N
|
3
|
Investigating or analysing materials by determining their chemical or physical properties
|
|
20
|
B04B
|
2
|
centrifuges
|