Layout of tunnels or galleries; Constructional features of tunnels or galleries, not otherwise provided for, e.g. portals, day-light attenuation at tunnel openings

Introduced: January 1980

Full Title

Full titles differ between systems:

IPC:

Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries > Layout of tunnels or galleries; Constructional features of tunnels or galleries, not otherwise provided for, e.g. portals, day-light attenuation at tunnel openings

CPC:

Tunnels or galleries, with or without linings; Methods or apparatus for making thereof (E02D29/045, E02D29/063 take precedence; linings per se E21D11/00); Layout of tunnels or galleries > Layout of tunnels or galleries; Constructional features of tunnels or galleries, not otherwise provided for, e.g. portals, day-light attenuation at tunnel openings

No child classifications to compare. This is a leaf node in both IPC and CPC.

Top Applicants

Top Applicants (IPC)

Class E21,2013–2023, worldwide · Source: EPO PATSTAT

HALLIBURTON ENERGY SERVICES GROUP US 26,607
PETROCHINA COMPANY 14,382
SINOPEC (CHINA PETROCHEMICAL CORPORATION) 10,137
CNPC (CHINA NATIONAL PETROLEUM CORPORATION) 6,517
BAKER HUGHES US 6,269
SCHLUMBERGER TECHNOLOGY US 5,929
SAUDI ARABIAN OIL COMPANY SA 5,880
SOUTHWEST PETROLEUM UNIVERSITY 4,477
CHINA UNIVERSITY OF MINING AND TECHNOLOGY 4,357
SCHLUMBERGER TECHNOLOGY NL 4,219

Top Applicants (CPC)

Class E21,2013–2023, worldwide · Source: EPO PATSTAT

HALLIBURTON ENERGY SERVICES GROUP US 27,652
SAUDI ARABIAN OIL COMPANY SA 7,755
PETROCHINA COMPANY 7,025
BAKER HUGHES US 6,589
SCHLUMBERGER TECHNOLOGY US 6,151
SINOPEC (CHINA PETROCHEMICAL CORPORATION) 4,443
SCHLUMBERGER TECHNOLOGY NL 4,255
CNPC (CHINA NATIONAL PETROLEUM CORPORATION) 3,991
SERVICES PETROLIERS SCHLUMBERGER FR 3,300
SCHLUMBERGER CANADA CA 3,086