GPI coverage and content

You can use Global Patent Index (GPI) to carry out detailed searches in the EPO's worldwide bibliographic (DOCDB), legal event (INPADOC) and full-text data sets, and download or visualise the search results for statistical analysis.

Current content: 158 817 061 patent documents

This week's update (27/09/2024 12:00 CET):

138 866 new documents added

722 000 documents amended

GPI key values

Run regular monitoring (e.g. monthly or quarterly) of technical areas or companies

Use built-in charts to visualise technical trends and patenting activity of companies

Choose the data you want to see and download to focus on what you are interested in

Run data quality assessments to measure the risk of incomplete search results

EP 0565141 A3 19931020 - ACOUSTIC DATA TRANSMISSION THROUGH A DRILL STRING

Title (en)

ACOUSTIC DATA TRANSMISSION THROUGH A DRILL STRING

Publication

EP 0565141 A3 19931020 (EN)

Application

EP 93111079 A 19890421

Priority

EP 93111079 A 19890421
US 18432688 A 19880421

Abstract (en)

[origin: EP0565141A2] Acoustical signals are transmitted through a drill string by canceling upward moving acoustical noise and by preconditioning the data in recognition of the comb filter impedance characteristics of the drill string. <IMAGE>

IPC 1-7

E21B 47/12

IPC 8 full level

E21B 47/16 (2006.01)

CPC (source: EP)

E21B 47/16 (2013.01)

Citation (search report)

[AD] US 4293936 A 19811006 - COX WILLIAM H, et al
[AD] US 4562559 A 19851231 - SHARP H EUGENE [US], et al

Designated contracting state (EPC)

DE FR GB NL

DOCDB simple family (publication)

EP 0565141 A2 19931013; EP 0565141 A3 19931020

DOCDB simple family (application)

EP 93111079 A 19890421