Apparatus for determining the curvature of an elongated hole
First Claim
1. An apparatus for determining the curvature of an elongated channel, said apparatus comprising a flexible probe which is intended to assume the curvature of the channel when inserted thereinto, said probe having sensing means for sensing the curvature of the probe and therewith the curvature of the channel, between at least two longitudinally spaced probe positions on the probe, said sensing means further including a first optical fibre section connected to a bendable probe body disposed in the probe and connected to said probe to accompany bending or curving of said probe, said first optical fibre section extending parallel with and at a constant distance from a bending neutral axis of the probe body so that the strain of the first optical fibre section will provide a measurement of the bending of the probe body in an axial plane that includes the first optical fibre section, said first optical fibre section including two partial reflection means at said longitudinally spaced probe positions along the probe body, a determination means connected to the first optical fibre section for interferometric determination of a change in distance between the partial reflection means in the first optical fibre section;
- and a compensating means for compensating for the influence of temperature on the change in distance between the partial reflection means.
1 Assignment
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Accused Products
Abstract
Apparatus for determining the curvature of an elongated channel, such as a drill hole in rock for instance, wherein the apparatus includes a probe (1) which may be constructed for movement through the channel and to assume the curvature of the channel at the different positions into which the probe is moved along the channel, wherein the probe (1) includes means (3, 31, 10) for sensing the curvature of the probe, and thus also the curvature of the channel, between at least two longitudinally spaced positions (A, B) on the probe (1), and wherein the apparatus can be connected to means (10) for determining the extension of the channel by registering curvature of the probe, for instance in different positions of the probe along the channel. The probe means include an optical fibre section (31) which is connected to a flexible probe body (3) arranged in the probe (1), wherein the optical fibre section (31) extends parallel with and at a constant distance from the bending neutral axis (44) of the probe body (3), such that strain acting in the fibre section will constitute a measurement of the bending or curvature of the probe body (3) in an axial plane (41) that includes the fibre section (31). The optical fibre section (31) has two partial reflection means(8a, 8b; 22a, 22b), for instance gratings, at said positions (A, B) along the probe. Means (10) are connected to the optical fibre section for interferometric determination of the change in distance between the partial reflection means in the fibre section (31). Means (32, 10) are provided for compensating for the influence of temperature on the change in distance between the partial reflection means.
34 Citations
14 Claims
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1. An apparatus for determining the curvature of an elongated channel, said apparatus comprising a flexible probe which is intended to assume the curvature of the channel when inserted thereinto, said probe having sensing means for sensing the curvature of the probe and therewith the curvature of the channel, between at least two longitudinally spaced probe positions on the probe, said sensing means further including a first optical fibre section connected to a bendable probe body disposed in the probe and connected to said probe to accompany bending or curving of said probe, said first optical fibre section extending parallel with and at a constant distance from a bending neutral axis of the probe body so that the strain of the first optical fibre section will provide a measurement of the bending of the probe body in an axial plane that includes the first optical fibre section, said first optical fibre section including two partial reflection means at said longitudinally spaced probe positions along the probe body, a determination means connected to the first optical fibre section for interferometric determination of a change in distance between the partial reflection means in the first optical fibre section;
- and a compensating means for compensating for the influence of temperature on the change in distance between the partial reflection means.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
Specification