RU2270993C2 - Device for controlling internal surface of bodies - Google Patents

Abstract

FIELD: technology for non-destructive control of internal surface of bodies by visual method.

SUBSTANCE: device has hollow cylinder-shaped body and, serially positioned inside it along its longitudinal axis, lighting system with electric lamp and toroidal lens, observation system, containing circular observation mirror, objective, light guide, scale mesh and ocular. Device additionally has second objective, positioned behind first ocular on its optical axis, television CCD-matrix, mounted in focal plane of second objective, video monitor, on screen of which images of light sections of object are visualized at output end of light guide, second replaceable ocular, positioned, during projection of first ocular from beams route, on optical axis parallel to optical axis of first ocular and distanced from it for distance equal to half diameter of image of light section of object at output end of light guide, and having possibility of rotation relatively to optical axis of first ocular.

EFFECT: possible observation of enlarged image of defects.

3 dwg

Description

The invention relates to non-destructive testing of the internal surface of bodies by a visual method.

A device for controlling the inner surface of bodies is known, comprising a hollow cylindrical body with a lighting system with an electric lamp and a toroidal lens, sequentially arranged inside it along its longitudinal axis, and a light section observation system for the object’s inner surface, containing a conical ring-shaped mirror, a lens, a light guide, a large-scale grid and the eyepiece [1].

The disadvantage of this device is the impossibility of observing an enlarged image of defects, which reduces the accuracy of measuring their size, as well as the absence of television surveillance tools that increase the comfort of observation and allow the implementation of computer image processing technologies.

To eliminate this drawback, we propose to additionally introduce into the optical circuit of the device a second lens located behind the first eyepiece on its optical axis, a television CCD array mounted in the focal plane of the second lens, a video monitor for visualizing the airborne matrix of television images, a second interchangeable eyepiece, located instead of the first eyepiece on the optical axis parallel to the axis of the first eyepiece and remote from it by a distance D / 2, where D is the diameter of the image of the light section of the object there is water at the output end, and the second eyepiece is mounted to rotate relative to the optical axis of the first eyepiece to align the optical axis of the second eyepiece with the center of the defect image, and the focal lengths of the first eyepiece f ₁ , the second eyepiece f ₂ , the second lens f ₀ , the diameter of the output the end of the fiber D _c , the size of the CCD matrix A, the maximum image size of the defect on the end of the fiber t _max , the diameter of the entrance pupil of the second pupil lenses of the second eyepiece D ₂ correspond to the relations:

D _with ≥D + 2t _max , D _g ≥D + D ₂ .

The device diagram is presented in figures 1 and 2.

The device comprises a hollow cylindrical body 1, in which a lamp 2, a toroidal lens 5, a conical mirror 4, a lens 5, a light guide 6, a scale mesh 7, a first eyepiece 8, a second lens 9, a CCD matrix 10, a video monitor are placed sequentially along its longitudinal axis 11, second eyepiece 12.

The device operates as follows.

The toroidal lens 3 forms a narrow ring of light on the inner surface of the object. The lens 5 using a conical mirror 4 forms at the input of the fiber 6 an image of this strip, which displays the profile of the object in a given section. The first eyepiece 8 and the second lens 9 form a telecentric system with a parallel beam path between the eyepiece and the lens.

In the focal plane of the lens 9, an image of the light section of the object observed at the output end of the fiber 6 is formed on the CCD matrix 10. The scale of this image is determined by the known ratio m = f ₁ / f ₀ [2] and is selected so that the image of the end of the fiber with a diameter of D _with fully fit into the CCD matrix of size A × A. The optical axis of the first eyepiece 8 and the second lens 9 coincide in space with the normal to the output end of the optical fiber 5 in its center.

When the first eyepiece 8 is pulled out of the path of the rays and a second eyepiece 12 is introduced into it with the help of known design techniques, the optical axis of which is parallel to the axis of the first eyepiece 4 and is D / 2 removed from it, a light beam is directed from the second eyepiece 9, whose axis is parallel to the axis of the second lens and passes through the center of the image of the defect perpendicular to the plane of the output end of the optical fiber 5.

The rotation of the second eyepiece relative to the axis of the second lens allows you to combine its axis with the center of the image of the defect at any point on the circle of diameter D at the output end of the fiber 6. Moreover, according to the properties of the telecentric system [2], the image of the defect is always formed in the center of the air defense matrix 10 with a scale of m ₂ = f ₂ / f ₀ , which is selected from the condition that the image of the defect of size 2t _max is fully entered into the CCD matrix of size A × A.

The doubled value of the defect image size is taken due to the possibility of observing both protruding defects above the surface (sagging, traces of metal splashes, etc.) and those located below it (shells, scratches, punctures, etc.). Obviously, the diameter of the second lens 9 must meet the condition D _g ≥D + D ₂ , where D ₂ is the diameter of the exit pupil of the second eyepiece.

Figure 2 shows the location of the elements of the optical scheme when introducing into the course of the rays of the first (Fig.2A) and second (Fig.2, b) eyepiece.

On figa shows a view of the screen of the video monitor when introducing the rays of the first eyepiece, and fig.3b view of the screen when introducing the rays of the second eyepiece.

Information sources

1. A.S. 1214259.

2. Reference designer of optical-mechanical devices. - L .: Engineering, 1982, 560s.

Claims (1)

A device for controlling the internal surface of bodies, comprising a hollow cylindrical body and a lighting system with an electric lamp and a toroidal lens, sequentially located therein along its longitudinal axis, a monitoring system comprising a conical mirror, a lens, a light guide, a scale mesh and an eyepiece, characterized in that it further contains a second lens located behind the first eyepiece on its optical axis, a television CCD array mounted in the focal plane of the second lens, a video monitor, on the wound of which the images of the light sections of the object are visualized at the output end of the fiber, the second interchangeable eyepiece located when the first eyepiece is pulled out of the beam on the optical axis parallel to the optical axis of the first eyepiece and at a distance D / 2 from it, where D is the diameter of the light section image object on the output end of the fiber and having the possibility of rotating relative to the first optical axis of the eyepiece, wherein the output end of the fiber diameter D _c, a first eyepiece focal lengths f _1, f ₂ of the second eyepiece, torogo lens f _0, the size of the CCD array A and the maximum value of the image defect at the end of the light guide t _max satisfy the following relations:

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