RU2417565C1 - Laser centrator for x-ray emitter - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: here is disclosed laser centrator consisting of centrator with enclosed in it laser. Optical axis of the laser is parallel to lengthwise axis of X-ray emitter. Further, the centrator consists of two deflectors. The first deflector is positioned on crossing point of laser axes and X-ray beam, while the second one is located on laser axis before its emitting end between it and the first deflector at distance H from the centre of the first deflector. This distance H is equal to distance from the centre to focus of an X-ray tube along axis of X-ray beam. A spherical lens is arranged before the emitting end of the laser and the second deflector. It forms a conic laser beam, geometrical parametres of which are identical to parametres of the X-ray beam. Perpendicularity of object surface to axis of X-ray beam is evaluated by degree of ellipticity of a light disk formed with the beam. Optical axis of lens of TV-camera coincides with axis traced from the centre of the second deflector perpendicular to axis of the laser and to a measuring scale for quantitative evaluation of defect dimensions on surface of an object and its perpendicularity to a beam of X-ray radiation. There are additionally introduced a computer and a laser range finder mounted on the case of the centrator beyond a zone of X-ray beam. Optical axis of the range finder is parallel to axis of the X-ray beam, while its digital output is conjugated with an input of the computer. The second deflector has a central orifice D=Dl transmitting the laser beam, where Dl is diametre of this beam. The computer automatically calculates a current value of C - a division value in plane of a scale object - shown on a screen of a display or generated with software, by ratio C=Co/M, where M is general magnification, Co is a division value of the scale of the screen of the display, M=MtxMo, where Mt=B/A is television magnification, A and B are dimensions of raster of a CCD-matrix and display correspondingly, Mo=F/L is optical magnification, where F is focus distance of TV-camera lens, and L is current distance from the object to the centrator.

EFFECT: avoiding both subjectivity in procedure for measuring distance to object and uncertainty of division value of scale on monitor screen depending on distance from object to centrator and corresponding to it value of scale of optical image.

1 dwg

Description

The invention relates to non-destructive testing using x-ray radiation and can be used to control materials and products in various engineering industries.

Known laser centralizer for an x-ray emitter, containing a laser with two-sided output of radiation and two reflectors, the first reflector is installed at the intersection of the optical axes of the laser and x-ray beams, the second is on the optical axis of the exit of laser radiation from its second end, a means of indicating the distance from the x-ray emitter to the object , two cylindrical lenses mounted on the axis of the laser in front of its ends, the first of which can be removed from the laser beam and replaced with a spherical lens that forms a conical light beam that is adequate in structure to the x-ray beam and creates a disk image on the surface of the object, the degree of elliptical distortion of which determines the perpendicularity of the surface of the object to the axis of the x-ray beam with the possibility of quantification using scales on the monitor screen of the television system, which is part of the centralizer [one].

The disadvantages of this device are the subjectivity of the method of measuring the distance to the object, as well as the uncertainty of the value of the scale division on the monitor screen, the value of which depends on the distance from the object to the centralizer and the corresponding value of the optical image scale. In addition, the presence of a beam splitter causes a significant weakening of the information flows of optical radiation.

The purpose of the invention is the elimination of these disadvantages.

To do this, in a laser centralizer containing a housing in which the laser is located, the optical axis of which is parallel to the longitudinal axis of the x-ray emitter, two reflectors, the first of which is made of plexiglass, is installed at the intersection of the laser and x-ray beam axes, and the second is mounted on the laser axis between its emitting the end face and the first reflector at a distance H from the center of the first reflector, equal to the distance from this center to the focus of the x-ray tube along the axis of the x-ray beam, a spherical lens mounted on the laser axis on the distance from the center of the second reflector at a distance equal to the focal length of the spherical lens, with which a conical laser beam is formed, coaxial with the x-ray beam, having the same angle of divergence and forming an image of a bright disk on the object, the diameter of which is equal to the diameter of the object’s area, illuminated by the x-ray radiation, and by the degree of its ellipticity they judge the perpendicularity of the surface of the object to the axis of the x-ray beam, a camera whose optical axis of the lens coincides with the axis conducted from the center of the second reflector perpendicular to the laser axis and a measuring scale for the quantitative assessment of the size of the surface defects of the object and its perpendicularity to the x-ray beam, characterized in that an additional computer and a laser range finder mounted on the centralizer case outside the x-ray beam propagation zone moreover, the optical axis of the rangefinder is parallel to the axis of the x-ray beam, and its digital output is coupled to the input of the computer, the second reflector is made n with a central hole for the passage of the laser beam, the center of this hole coincides with the point of intersection of the focal plane of the spherical lens with the axis of the laser beam, and its diameter D = L, Dl is the diameter of the laser beam, the computer automatically calculates the current value of the scale division value, set to a computer display screen or formed by software according to the ratio C = Co / M, where M is the image scale equal to M = Mt × Mo, where Mt = B / A is the television magnification, A and B are the sizes of the rasters of the CCD matrix and the display screen, respectively venno, Mo = F / L - optical magnification, F - focal distance of the camera lens, L - distance from the current object to the centralizer.

The invention is illustrated in the drawing, which shows a diagram of a centralizer.

The laser centralizer contains an X-ray emitter 1, to which a housing 2 is attached, in which the first plexiglass reflector 3, the second reflector 4, the spherical lens 5, the laser 6, the zoom lens 8 with a light filter 7 of a CCD camera 9, a computer 10 and laser rangefinder 11. The filter 7 has a maximum transmission in the wavelength region emitted by the laser 6, and is intended for contrasting images of laser structures on the object.

The centralizer works as follows.

When the lens 5 is removed from the laser beam, the laser 6 forms a bright dot on the object 12, which, using the means of moving the centralizer, is combined with the center of the controlled zone. Then the lens 5 is introduced into the laser beam and on the monitor 13 observe the image of the light disk. If it has ellipticity, it is eliminated by performing linear and angular movements of the centralizer. If necessary, a quantitative assessment of the degree of ellipticity of the disk and / or the size of the surface defects of the object using measuring scales on the monitor screen is performed. At the same time, the current division price of these scales and the current distance from the centralizer to the lens are displayed on the computer display. After completing these procedures, they begin to x-ray the control object.

Here are some numerical estimates of the calculation of the division price of measuring scales according to the above relations.

As a rule, the scale division price on the display screen is selected from ergonomic and technological considerations equal to Co = 1 mm. The raster size of the CCD matrices is usually in the range A = 5-10 mm, and the screen size of the monitor of portable mobile devices is B = 150-200 mm. The distance from the centralizer to the object is usually within L = 3-5 m.

The focal length of the camera lens for imaging objects at these distances is selected based on the requirements for the field of view angle and resolution of the television system and is usually in the range of F = 50-100 mm.

For the characteristic values of these parameters, A = 10 mm, B = 200 mm, L = 5000 mm, F = 50 mm, we will have Mt = 20, Mo = 0.01, M = 0.2, and C = Co / M = 1 / 0.2 = 5 mm, i.e. 1 mm of the scale on the screen corresponds to 5 mm in the plane of the object. For example, if the image of a defect on the display screen occupies 20 mm (and, accordingly, 20 divisions of the scale), then its true size in the plane of the object will be 100 mm for the above characteristic values of the parameters of the television system.

It should be noted that the formula for calculating the optical magnification is approximate and is valid for the ratio of the focal length of the lens and the distance from the centralizer to the object, at which L> 30F, which almost always takes place during radiation monitoring of large-sized products of aircraft [2].

Literature

1. RF patent 2250575. Laser centralizer.

2. Reference designer of optical-mechanical devices. Panov V.A. et al. L .: Engineering, 1980, 742 p.

Claims (1)

A laser centralizer comprising a housing in which a laser is located, the optical axis of which is parallel to the longitudinal axis of the x-ray emitter, two reflectors, the first of which is made of organic glass at the intersection of the laser and x-ray axes, and the second is mounted on the laser axis between its emitting end and the first reflector at a distance H from its center, equal to the distance from this center to the focus of the x-ray tube along the axis of the x-ray beam, a spherical lens mounted on the laser axis at a distance from the center of the second about the reflector at a distance equal to the focal length of the spherical lens with which a conical laser beam is formed, coaxial with the x-ray beam, having the same angle of divergence and forming on the object an image of a light disk, the diameter of which is equal to the diameter of the object’s area, which is exposed to x-ray radiation, and by the degree of its ellipticity they judge the perpendicularity of the surface of the object to the axis of the x-ray beam, a camera whose optical axis of the lens coincides with the axis drawn from the center of the W of a reflector perpendicular to the laser axis and a measuring scale for quantifying the size of defects on the surface of the object and its perpendicularity to the x-ray beam, characterized in that it additionally includes a computer and a laser range finder mounted on the centralizer body outside the x-ray beam propagation zone, the optical axis the range finder is parallel to the axis of the x-ray beam, and its digital output is coupled to the input of the computer, the second reflector is made with a Central hole In order to pass the laser beam, the center of this hole coincides with the point of intersection of the focal plane of the spherical lens with the axis of the laser beam, and its diameter is Д = Д, Дл is the diameter of the laser beam, the computer automatically calculates the current value of the scale division value set on the computer screen or formed programmatically by the ratio C = Co / M, where M is the image scale equal to M = Mt × Mo, where Mt = B / A is the television magnification, A and B are the sizes of the rasters of the CCD matrix and the display screen, respectively, Mo = F / L - Optical elichenie, F - focal distance of the camera lens, L - current distance to the object from the centralizer.