CPC Main Group
E21D 9/00 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
Filing statistics
CPC E21D 9/00 belongs to the parent subclass E21D, which recorded 43,973 patent applications worldwide between 2013 and 2023. Annual filings grew from 1,000 in 2013 to 6,074 in 2023 (+507%), peaking at 6,255 applications in 2020. The most active applicants in class E21 are HALLIBURTON ENERGY SERVICES GROUP (27,652 applications), SAUDI ARABIAN OIL COMPANY (7,755 applications) and PETROCHINA COMPANY (7,025 applications).
Source: EPO PATSTAT, worldwide filings
13 direct subcodes
Child Classifications
Navigate with arrow keys, Enter to open
- E21D 9/01 Methods or apparatus for enlarging or restoring the cross-section of tunnels, e.g. by restoring the floor to its original level
- E21D 9/02 Driving inclined tunnels or galleries
- E21D 9/04 Driving tunnels or galleries through loose materials; Apparatus therefor not otherwise provided for
- E21D 9/06 Making by using a driving shield
- E21D 9/10 Making by using boring or cutting machines (E21D9/08 takes precedence; mining picks E21C35/18)
- E21D 9/12 Devices for removing or hauling away excavated material or spoil; Working or loading platforms (underground transport E21F13/00)
- E21D 9/14 Layout of tunnels or galleries; Constructional features of tunnels or galleries, not otherwise provided for, e.g. portals, day-light attenuation at tunnel openings
Top Applicants
Top 10 applicants by patent filingsfor 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