GB1584304A

GB1584304A - Seismic wave detectors

Info

Publication number: GB1584304A
Application number: GB280/80A
Authority: GB
Original assignee: IFP Energies Nouvelles IFPEN
Current assignee: IFP Energies Nouvelles IFPEN
Priority date: 1976-07-02
Filing date: 1977-07-01
Publication date: 1981-02-11
Also published as: DE2729905C2; NL7707298A; DK143523B; DE2729905A1; SE7707584L; AU2655977A; DK293577A; JPS60220886A; DK143523C; BE856235R; AU513212B2; JPS5333651A; NO772313L; IT1114621B; JPS614061B2; GB1584303A; NO144863B; NO144863C

Description

PATENT SPECIFICATION

-4 t ( 21) Application No 280/80 ( 22) Filed 1 July 1977 I ( 62) Divided out of No 1 584 303 Icn ( 31) Convention Application No.

-, 7620550 ( 32) Filed 2 mr 00 tn ( 33) France (FR) ( 44) Complete Specification published 11 Feb 1981 ( 51) INT CL ' HO 4 R 19/00 ( 52) Index at acceptance H 4 J 30 M 31 A 31 W C ( 72) Inventor JEAN-CLAUDE DUBOIS ( 11) 1 584 304 July 1976 in ( 54) SEISMIC WAVE DETECTORS ( 71) We, INSTITUT FRANCAIS DU PETROLE, a body corporate organised and existing under the laws of France, of 4 avenue de Bois-Preau, 92502 RuelMalmaison, France, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: -

This invention relates to seismic wave detectors, and is more particularly directed to a modification of the invention which is the subject of our Patent No 1 505 664 (hereinafter referred to as ' the parent patent ').

Claim 1 of the parent patent recites a seismic wave detector for seismic prospecting of a medium, the detector comprising an elongate sensitive assembly that comprises a deformable electret, two electrodes located one on each side of the deformable electret, and a compressible and electrically insulative flexible member located between the deformable electret and one of the electrodes, the sensitive assembly being so arranged that at least one surface thereof defines or is adjacent to a surface of the detector that, in use, contacts the medium along the length of the detector.

According to the invention there is provided a seismic wave detector for seismic prospecting of a medium, according to claim 1 of the parent patent, modified in that a first of the electrodes of the sensitive assembly and the compressible and electrically insulative flexible member are replaced by a single member which acts as the first electrode and which has recesses regularly distributed over a face thereof in contact with another component of the sensitive assembly.

The invention will now be further described, by way of illustrative and nonlimiting example, with reference to the accompanying drawing, the sole figure of which shows a seismic wave detector constituting an embodiment of the invention.

The embodiment of Figure 1 of the parent patent may be replaced by the arrangement shown in the sole figure hereof, in which the first electrode and the compressible element of Figure 1 of the parent patent are replaced by a flat element 21 of electrically conductive material 55 having regularly spaced recesses in the surface, formed for example by recesses of parallelepipedal, pyramidal or cylindrical shape or formed as a portion of a sphere.

The recesses in the surface may be pro 60 duced:

by adding a material on a flat strip, e g.

by depositing a metal by electrolysis or depositing a varnish by means of a screen; by mechanical or chemical engraving of 65 the surfaces of a flat metal strip; or by milling or stamping.

The element 21 forms the first electrode.

The second electrode is a metallised film in contact with the electret 4 During 70 the manufacturing operation, the electret strip 4 is disposed on the element 21 and the air contained in the recesses is trapped.

Since air is a compressible fluid, the volume of air in the recesses defined between the 75 facing surfaces of the element 21 and the electret strip 4 varies in response to stresses exerted on the other electrode 5 Accordingly, the element 21 acts similarly to a compressible perforated strip as used in the 80 embodiment of Figure 1 of the parent patent.

Claims

WHAT WE CLAIM IS: -

1 A seismic wave detector for seismic prospecting of a medium, according to 85 claim 1 of Patent No 1 505 664, modified in that a first of the electrodes of the sensitive assembly and the compressible and electrically insulative flexible member are replaced by a single member which acts as 90 the first electrode and which has recesses regularly distributed over a face thereof in contact with another component of the sensitive assembly.

2 A seismic wave detector according to 95 claim 1, wherein said other component is the deformable electret.

3 A seismic wave detector for seismic prospecting of a medium, the detector being substantially as herein described with 100 1 584304 reference to the accompanying drawing.

4 A method of manufacturing a detector according to claim 1 or claim 2, wherein the recesses are obtained by depositing additional material on a flat strip.

A method of manufacturing a detector according to claim 1 or claim 2, wherein the recesses are obtained by engraving the surface of a flat strip.

For the Applicants:

D YOUNG & CO, Chartered Patent Agents, Staple Inn, London WC 1 V 7RD.

Printed for Her Majesty's Stationery Office by The Tweeddale Press Ltd, Berwick-upon-Tweed, 1980.

Published at the Patent Office, 25 Southampton B uildings, London, WC 2 A l AY, from which copies may be obtained.