RU87021U1 - DEVICE OF NON-DESTRUCTIVE X-RAY CONTROL OF WELDED RING SEAMS OF TUBULAR ELEMENTS - Google Patents

Abstract

1. A device for non-destructive x-ray inspection of welded annular seams of tubular elements containing an x-ray emitter, a collimator, a movement system, a detector of x-ray radiation transmitted through the weld, and an indicator unit for converting the radiation image of the weld into a radiographic image, characterized in that the x-ray emitter represents a rod-shaped anode of the x-ray apparatus, intended for insertion into the cavity of the tubular element and the implementation of x-ray radiation, the collimator is located in front of the X-ray detector and is made in the form of a disk with radially directed slots, while the specified disk is rotatable around the longitudinal axis of the anode to pass through the X-ray slots in the direction of the X-ray detector, the disk is mounted on a cone-shaped sleeve mounted on the anode to block the inlet of the tubular element when the anode is inserted into the cavity of this element, and the movement system is configured to reciprocating movement of the anode in horizontal and vertical directions. ! 2. The device according to claim 1, characterized in that an X-ray film is used as an X-ray detector, on the back of which there is a lead plate. ! 3. The device according to claim 1, characterized in that it is provided with guiding elements in the form of rods arranged on the sides of the anode for insertion into the cavity of tubular elements adjacent to the tubular element into which the ano is inserted

Description

The utility model relates to test equipment and can be used for non-destructive testing of circular welds of welded elements on pipes and cylindrical products, and can be used in engineering technology. In particular, the utility model relates to nuclear energy and may find application in the manufacture of shells for fuel elements, mainly for nuclear power reactors. The utility model also relates to the field of flaw detection, in particular to non-destructive testing of the quality of annular welds of main pipelines by panoramic scanning with penetrating radiation, and can be effectively used in the construction of gas and oil pipelines or their repair.

A known method of non-destructive quality control of annular welds of main pipelines by panoramic scanning of welds from the inside of the pipe using a gamma source or x-ray radiation (hereinafter referred to as the emitter), which is part of a self-propelled flaw detector moving along the pipe according to commands sent by the penetrating radiation source (hereinafter - command apparatus) located outside the pipe and acting on the flaw detector motion control device. The described control method was implemented using self-propelled flaw detectors of X-MAS (USA), OIS (ENGLAND), JME LTD (ENGLAND), SOLUS OCEANEERING Int., Inc. (USA), GAMMAMAT (GERMANY). A self-propelled flaw detector consists of an x-ray or gamma source with panoramic radiation (emitter), a self-propelled trolley designed to move the emitter inside the pipe, a control device located on the trolley and designed to receive signals from the command apparatus, process them and turn on the actuators (trolley engine, emitter exposure timer, etc.). Flaw detector motion is controlled using a command device that provides control signals for the truck’s movement, stopping the emitter, and turning on the emitter (Isotope test moth for pipeline construction GAMMAMAT, Isotope Technique Avenue. Dr. Sauerwein GmbH, Germany; Prospectus for Oil Field bispecnion Services Ltd (OIS) , England, 1985; JME Pipeline X-Ray Crawlers, prospectus of JME LTD, England; SU No. 1446034, G01N 23/18, 1984; RU No. 2123683, G01N 23/18, G01N 23/02, publ. 1998.12.20).

In all known methods of controlling annular welds by panoramic scanning from the inside of the pipe using self-propelled flaw detectors, a radioactive isotope, for example, iridium-192, mounted outside the pipe and emitting gamma rays through the wall into the pipe, is used as a command apparatus. When the flaw detector is raised under the beam of gamma-quanta of the command apparatus, the electronic circuit for controlling the flaw detector motion is triggered, and it stops in the position when the emitter is installed in the position opposite the weld. Next, the emitter automatically fulfills a given exposure, showing through panoramic the entire annular seam. An image of the weld is recorded, for example, with a film, which is applied to the controlled seam in advance.

A significant disadvantage of this method is also the radiation hazard for staff, since the flaw detector is controlled by a command isotope, which the operator holds directly in his hands, while making the necessary isotope movements (by swings) along the pipe. Despite the radiation protection measures taken, the risk of exposure, especially of unskilled personnel, is very likely. In addition, the operation of isotopes is difficult, as it requires the availability of special containers for storage, as well as reloading of isotopes at specialized enterprises as they develop their resources. The disadvantages of the known methods for controlling welds using known self-propelled flaw detectors also include the ability to control welds in tubular products of only large diameter.

The disadvantages of this known method are partially eliminated by the method of non-destructive quality control of the ring joint (welded butt joint of pipes) (S.A. Ivanov, N.N. Potrakhov, G.A. Shchukin "Specialized X-ray machine for microdefectoscopy. Electronic equipment", series 4. Vacuum and gas-discharge devices, Issue 2 (125), 1989, p. 100). In this method, shooting is carried out by the contact method with the location of the x-ray source (remote anode of the x-ray tube) in the cavity of the tube, and the radiation detector is on the outside of the seam. The method allows to obtain an image of the seam without overlapping images of diametrically opposite sections of the annular connection. In this case, the anode must be inserted into the cavity of the pipe to a depth sufficient for the radiation field to “cover” the seam over its entire height.

The use of this method for transillumination of the ring connection does not give the desired result due to the fact that in the immediate vicinity of the seam there are other structural elements. By virtue of this, the anode cannot be installed in a position that will ensure the filming of the seam along its entire height.

Thus, there is a technical contradiction: the known contact methods of radiographic quality control of an annular seam either have insufficiently high contrast sensitivity due to the overlapping image of the opposite (back with respect to the radiation source) wall, or do not allow the seam to be taken along its entire height. In addition, all known methods allow you to shoot a seam only in the radial direction. However, to obtain a reliable picture of the state of the seam, it is necessary to perform additional shooting along the height of the seam.

A known method of non-destructive quality control of an annular connection, including its X-ray transmission, in which the studied area is placed between the x-ray source and the radiation detector, while excluding the possibility of getting into the radiation passage zone a diametrically opposite section of the connection, while the plane in which the focal spot of the radiation source is located , removed from the surface of the cover in the direction from the center of the tubular product at a distance not exceeding the radius of the ring connection, and the "central beam" of the source radiation flux is oriented to the studied area at an angle not exceeding 45 ° to the lid surface, the focal length is chosen commensurate with the diameter of the ring connection, the distance between the focal spot of the radiation source and the radiation detector is 1.5 -3 times the distance between the focal spot and the surface of the investigated area, while using a source whose determining size of the focal spot is 1.5-3 times less than the absolute value of additional ska changes suture sizes of elements (RU №2175126, G01N 23/18, publ. 2001.10.20).

In the known solution, an X-ray sensitive film can be used as a detector, and X-ray television detectors, including digital ones, with image transmission to a monitor, can be used for express analysis. To obtain a complete picture of the quality of the seam when shooting, it is necessary to rotate the product around its axis. Thus, as can be seen from the x-rays presented in the drawings to the description, the method allows to obtain a complete image of the seam, including along its entire height in at least two projections. Given the image scale and due to the high image sharpness, the measurement error of the main parameters of the seam does not exceed 0.05 mm.

There is a method of control and sorting of the welds of the shells with plugs of fuel elements ("Development, production and operation of fuel elements of power reactors." Book 2, F. G. Reshetnikov, Yu. K. Bibilashvili, I. S. Golovnin, etc. .. Under Edited by F.G. Reshetnikova, M, Energoatomizdat, 1975, pp. 268-271) includes operations of random inspection of the welds of the shells with the lower plugs by X-raying of the welds with rotation of the shells around its axis, transforming the radiation image of the weld wa to a radiographic image with subsequent conversion to a light image and sorting

In welds on shells made of zirconium alloys made by electron beam welding, the most common defects are pores, fusion at the root of the joint, gas channels in the form of root swelling in the interface between the shell and the plug. The greatest difficulty is the identification of lack of fusion at the root of the seam with a small opening and small pores. The design of the sealing welds is very unfavorable for radiography, since the thickness of the translucent material varies from a maximum (in diameter) to zero (tangent). Therefore, radiography of welded joints by this method is carried out in three to six positions of the shell with a rotation around the axis of 120-60 °. At the same time, useful information about the quality of the welded joint is obtained only in two small diametrically opposite sections, which does not fully characterize the weld. The angle of rotation of the shell around its axis is also important, since only a clear angle of rotation can give complete information about the quality of the weld seam of the shell with a plug, and approximate rotations of the shell around its axis will give approximate information about the quality of the weld.

A technical solution is known - a device for studying the internal structure of objects, which provides shadow projections of sections of the studied object by scanning it with a collimated x-ray beam and detecting radiation transmitted through the object by a detector that generates electrical signals representing the corresponding shadow projections (GB No. 1283915, G01N 23 / 08, publ. 1975).

This device is the basis of x-ray computed tomography, according to which, using the shadow projections obtained from various angular directions, computing means are used to restore the image of the scanned layer of the object under study. In the known device, the spatial resolution obtained in the obtained shadow projections is determined primarily by the dimensions of the collimated beam and / or detector in the scanning direction, i.e. if there are finer details of the structure in the studied object, the latter may not be detected in the resulting shadow projection.

A known device for radiation research of the internal structure of objects, which consists in producing at least one shadow projection of the cross section of the studied object by scanning it with a collimated x-ray beam and detecting the radiation transmitted through the object with the formation of electrical signals, while the studied object and the collimated beam are moved relative to each other (RU No. 2069853, G01N 23/08, publ. 1996).

A disadvantage of the known technical solution is that it is collimated beams that are moved relative to the object to obtain shadow images, which complicates the overall design, increases the requirements for radiation protection, and the possibility of gaps in the control of the object due to sudden movements of the emitter.

A device for non-destructive x-ray inspection of welded annular seams of tubular elements, containing an x-ray emitter, a collimator, a movement system, a detector of x-rays transmitted through the weld, and an indicator unit for converting the radiation image of the weld into a radiographic image (U. Zscherpel, O.AIekseychuk, P. Rost, V. Schid, K. Spardotis, A. Wanikhoff "Anew fully digital system for RT inspection of metal tube to tube sheet joints of heat exchanger." 17 ^th World Conference on Nondestructive Testing, 25-28 Oct 2008, Shanghai , China) (accepted as a prototype).

The disadvantage of this solution is the great complexity of control, since for one seam it is necessary to conduct four studies and the four images obtained along the angular zones of the seam are then combined. This device cannot take the opportunity to conduct a comparative analysis of several measurements at different seams. Since there is no regulation of the positioning of the x-ray emitter relative to the entrance to the pipe hole in the weld zone.

This utility model is aimed at achieving a technical result, which consists in increasing the reliability of control of welds of tubular welded shells and simplifying the operation to obtain radiographs (images) of the weld while eliminating the need to move the collimator relative to the tubular element. The utility model also improves the safety of quality control of annular welds of tubular products while ensuring ease of control and a sufficiently high speed of control.

The specified technical result is achieved by the fact that in the non-destructive X-ray inspection device of the welded annular seams of the tubular elements comprising an X-ray emitter, a collimator, a movement system, an X-ray detector passing through the weld, and an indicator unit for converting the radiation image of the weld into a radiographic image, an X-ray the emitter is a rod-shaped anode of an x-ray apparatus with a target emitter, intended for introduction into the cavity of the tubular element and the implementation of x-ray radiation in the direction of the emitter target, the collimator is located in front of the x-ray detector and is made in the form of a disk with radially directed slits, while the specified disk is made to rotate around the longitudinal axis of the anode to pass reflected x-rays through the slots in the direction to the X-ray detector, the disk is mounted on a cone-shaped sleeve mounted on the anode to block the tubular inlet element when you enter the anode into the cavity of this element, and the movement system is configured to reciprocate the movement of the anode in the horizontal direction and in the vertical direction.

In this case, an X-ray film may be used as an X-ray detector, on the back of which there is a lead shield. And on the sides of the anode can be mounted guide elements in the form of expanded rods designed to enter into the cavity of the tubular elements adjacent to the tubular element into the cavity of which the anode is inserted. And on the case of the x-ray emitter mounted device for powering the x-ray emitter when you enter the anode into the cavity of the tubular element until it stops in the conical sleeve.

These features are significant and are interconnected with the formation of a stable set of essential features sufficient to obtain the desired technical result.

The present utility model is illustrated by a specific example of execution, which, however, is not the only possible one, but clearly demonstrates the possibility of achieving the required technical result.

Figure 1 shows a diagram of an x-ray control device;

figure 2 - design of a disk collimator;

figure 3 - annular welds in the shell;

4 is an x-ray image of the annular weld.

According to this utility model, a device for non-destructive testing of circular welds of welded tubular elements is considered, based on the fact that the weld of the welded tubular element is exposed to X-ray radiation, then the detector receives the x-ray radiation transmitted through the weld and converts the radiation image of the weld into a radiographic image.

A feature of this device is that the rod type anode of the X-ray apparatus is used as the source of the X-ray radiation, which is introduced into the cavity of the tubular element with the emitter target moving through the zone of the circular weld. After passing the target emitter through the zone of the circular weld, this target is stopped (fixed) at a distance from this weld when the zone of the circular weld is placed between the emitter and the detector.

X-ray radiation is directed in the direction of the circular weld, and the X-ray detector receives X-rays transmitted through the weld zone through a rotating slotted collimator, the slots of which are made radially directed.

X-ray inspection devices of circular welds of welded tubular elements (Figs. 1, 2) are a rod-shaped anode 1 (made in the form of a rod) of an X-ray apparatus 2, an X-ray reception detector 3 (for example, an X-ray film is used as a detector, behind which located lead plate 5 - protection). A collimator 6 is arranged in front of the detector in the form of a disk with radially directed slots 7. The disk is made to rotate around the longitudinal axis 8 of the anode to pass X-rays through the slots towards the detector. The drive of rotation of the disk includes a driving wheel 9 (driving pulley), kinematically coupled to an electric motor and covered by a belt 10, which is laid in an annular groove on the disk (the disk acts as a driven wheel - pulley).

The disk is rotatably mounted on a cone-shaped sleeve 11 mounted on the anode to block the inlet of the test tubular element 12 when the anode is inserted into the cavity of this element.

For example, in the presented example, an X-ray film is used as an X-ray detector, on the back of which there is a lead plate.

A device for switching on the power of the X-ray emitter is mounted on the case of the X-ray emitter when the anode is inserted into the cavity of the tubular element until it stops in the conical sleeve. For example, on the case of the emitter (it is on the right and the anode tube exits) there is a blocking microswitch (not shown) that allows you to turn on a high voltage, that is, x-ray radiation, only when the radiating end of the anode tube has entered the controlled tube, thereby absorbing radiation going not backward, but sideways with the mass of this whole tube board. Radiation (excess), traveling back along the anode tube, is absorbed by a layer of lead, dressed on the anode behind the film. All this to ensure radiation safety. The device is equipped with guide elements 13 in the form of rods arranged on the sides of the anode intended for insertion into the cavity of tubular elements adjacent to the tubular element into the cavity of which the anode is inserted. These rods (guides) are designed to position the anode in the cavity of the tested tubular element and the possibility of its movement from one cavity to another cavity (adjacent tubular element) while ensuring the same conditions for the position of the anode in the cavity.

The device is positioned relative to the inlet of the tubular element 12, a circular weld 14 welded to the base surface 15, for example, to the shell for fuel elements of a nuclear power reactor (figure 3). Then the longitudinal movement of the anode is introduced into the cavity of the tubular element until it stops against the conical surface of the sleeve in the annular weld. The end is located behind the seam in the cavity of the tubular element (figure 1). The collimator disk is rotated and X-ray radiation is carried out. The radiation is directed towards a rotating collimator, through which only direct rays transmitted through radial slots pass onto the x-ray film. As a result, an X-ray image 16 of the annular weld is formed on the film, according to which the quality of welding, the presence of cracks, lack of penetration and other defects are visually determined (Fig. 4). With a quality-welded seam in the image, an annular image is uniform in color and tone, and if there are cracks in the picture, light streaks are visible.

A feature of such a device is that for one radiation pulse, the tester receives complete information about the state of the weld along its entire circumference. When used as a detector, for example, an X-ray television installation, including digital, the image can be transmitted directly to the monitor. The device has the following important features:

- in the manual control mode, the radiation source (x-ray machine) is placed on the frame and has 6 degrees of freedom due to the possibility of movement of its supporting frames. This allows you to precisely match the movement of the radiation source with the pitch of the holes in the heat exchanger, which has a mass of more than a ton and does not move relative to the device.

- control is carried out automatically according to a given program of movements and exposure modes. The manual part of the work is only changing the cassettes with the film and rearranging the guide rods, the need for which is indicated at some points on the tube plate by the program.

- the anode of the x-ray machine, when it is inserted into the tube, is insured against damage by three guide rods that enter into adjacent holes, in case of a mismatch between the movement step of the device and the hole pitch, which may occur, for example, due to small inaccuracies when drilling these holes for the holes inserted into them pipes.

- the mounting of the X-ray apparatus in the movable frame is spring-loaded so that in the case of the disagreement between the movement step and the hole pitch, the radiation source can be centered relative to the next hole due to the efforts of the guiding (safety) rods that occur when these rods come in contact with the walls of adjacent holes.

Using such a device, it becomes possible to carry out non-destructive testing of circular welds of welded tubular elements in the pipe-tube board system. The control is based on the fact that the rod-shaped anode of the X-ray apparatus is introduced into the cavity of the tubular element, moved through the zone of the circular weld, where the emitter is fixed at a distance from this seam (the zone of the circular weld is placed between the target and the detector). Then carry out x-ray radiation in the direction of the seam. An X-ray detector (for example, on an X-ray film) receives X-ray radiation that has passed through the weld zone and passes through the slots of a rotating slotted collimator, the slots of which are made radially directed. A feature of this method is that in such a process, only direct rays of the x-ray stream reflected from the target are projected onto the detector. Radiation fluxes reflected from the walls of the tubular element, which interfere with the image of the radiographic image, do not fall on the detector, which allows you to get a "clean" translucency of the circular weld.

The presence of a sleeve with a conical part makes it possible to securely install the anode in the cavity of the tubular element in a predetermined positional position approximately along the longitudinal axis of this element, which makes it possible to form reflected radiation uniformly around the circumference of the target. Such an approach makes it possible to obtain a uniformly illuminated circular field (for a qualitatively welded seam) in a radiographic image and to reveal inhomogeneities in the weld structure that are not hidden by the influence of secondary radiation reflected from the tube walls.

This utility model is industrially applicable, tested in laboratory conditions and has shown high efficiency in obtaining reliable information about the structure of a circular weld in a single X-ray pulse. In this case, due to the fixed positioning of the anode in the tubular element, it is possible to compare the seams of adjacent welded tubes of the heat exchangers of nuclear reactors.

Claims (4)

1. A device for non-destructive x-ray inspection of welded annular seams of tubular elements containing an x-ray emitter, a collimator, a movement system, a detector of x-ray radiation transmitted through the weld, and an indicator unit for converting the radiation image of the weld into a radiographic image, characterized in that the x-ray emitter represents a rod-shaped anode of the x-ray apparatus, intended for insertion into the cavity of the tubular element and the implementation of x-ray radiation, the collimator is located in front of the X-ray detector and is made in the form of a disk with radially directed slots, while the specified disk is rotatable around the longitudinal axis of the anode to pass through the X-ray slots in the direction of the X-ray detector, the disk is mounted on a cone-shaped sleeve mounted on the anode to block the inlet of the tubular element when the anode is inserted into the cavity of this element, and the movement system is configured to reciprocating movement of the anode in horizontal and vertical directions. 2. The device according to claim 1, characterized in that an X-ray film is used as an X-ray detector, on the back of which there is a lead plate. 3. The device according to claim 1, characterized in that it is provided with guiding elements in the form of rods arranged on the sides of the anode for insertion into the cavity of tubular elements adjacent to the tubular element into the cavity of which the anode is inserted. 4. The device according to claim 1, characterized in that on the housing of the x-ray emitter mounted device for powering the x-ray emitter when you enter the anode into the cavity of the tubular element until it stops in the conical sleeve.