RADIOPROTECTIVE CONTAINER FOR RADIOMETRIC MEASURING DEVICES

Abstract

A radiation protection container of a measuring system serves for radiometric density or fill level measurement. The radiation protection container is based on two base bodies connected to one another via a planar surface. The radiation waveguide extends for focused emission in a plane defined by the planar surface, wherein the radiation waveguide is formed by depressions in the base body surfaces. The radiation protection container comprises radiation absorption structures formed by depressions and complementary elevations in the base body surfaces lying on top of each other. An advantage is that refractory base bodies based on steel can be used and it is possible for the depressions and/or elevations to be realized using surface machining. The radiation absorption structures ensure that no radiation exits the radiation protection container laterally.

Claims

1-11. (canceled)

12. A radiation protection container for a radiation source of a measuring system for radiometric density or fill level measurement, comprising: a first base body having a first planar surface, a second base body having a second planar surface, a first connecting structure which connects the first base body and the second base body to the surfaces in a form-fitting manner, in such a way that the surfaces define a planar plane, a straight-axis radiation waveguide extending in the plane, which is formed by the two base bodies, having a first open end region to which the radiation source can be fixed, and a second open end region, at least one first radiation absorption structure, which is formed by depressions and complementary elevations in the first surface and in the second surface, respectively, such that the first radiation absorption structure extends in the plane, proceeding from the radiation waveguide.

13. The radiation protection container according to claim 12, wherein the radiation absorption structure has a profile proceeding from the radiation waveguide in each case.

14. The radiation protection container according to claim 12, wherein the radiation absorption structure has a profile in the plane, in relation to the beam axis, which is curved in the shape of a circular segment by up to 90 towards the first end region.

15. The radiation protection container according to claim 12, comprising: three radiation absorption structures arranged in the plane, which are arranged in each case at an increasing distance from the first end region, in relation to the beam axis.

16. The radiation protection container according to claim 12, wherein the radiation absorption structure has a rectangular cross section.

17. The radiation protection container according to claim 12, wherein the first base body and/or the second base body is/are made of a steel.

18. The radiation protection container according to claim 12, wherein the first connecting structure is configured as a screw connection.

19. The radiation protection container according to claim 17, wherein the first connecting structure is configured as a welded connection.

20. A measuring system for radiometrically determining the density and/or fill level of a filling material located in a container, comprising: a radiation protection container, including: a first base body having a first planar surface, a second base body having a second planar surface, a first connecting structure which connects the first base body and the second base body to the surfaces in a form-fitting manner, in such a way that the surfaces define a planar plane, a straight-axis radiation waveguide extending in the plane, which is formed by the two base bodies, having a first open end region to which the radiation source can be fixed, and a second open end region, at least one first radiation absorption structure, which is formed by depressions and complementary elevations in the first surface and in the second surface, respectively, such that the first radiation absorption structure extends in the plane, proceeding from the radiation waveguide; wherein the radiation protection container can be attached, in relation to the container, such that the second end region of the radiation waveguide is directed away from the container, a radioactive radiation source which is fixed to the first end region of the radiation waveguide, a detector unit which can be attached to the container, opposite the radiation source, in the beam axis, in order to detect a radiation intensity of the radiation source after passing through the filling material, an evaluation unit which is designed to determine the density and/or the fill level of the filling material in the container on the basis of the received radiation intensity.

21. The measuring system according to claim 20, wherein the radiation source can be fastened to the radiation protection container using a screw connection in such a way that a thread axis of the screw connection extends in parallel with the beam axis.

22. The measuring system according to claim 21, wherein the radiation source is arranged having a defined radial offset with respect to the thread axis of the screw connection, and wherein the radiation waveguide is arranged such that its beam axis has the defined radial offset to the thread axis of the screw connection.

Description

[0025] The invention is explained in greater detail with reference to the following figures, in which:

[0026] FIG. 1: shows a radiometric measuring instrument on a container,

[0027] FIG. 2: shows a first cross-sectional view of the radiation protection container according to the invention, and

[0028] FIG. 3: shows a second cross-sectional view of the radiation protection container according to the invention.

[0029] For general understanding of radiometric density and fill level measurement, FIG. 1 shows a container 2 which is filled with a filling material 1. Depending on the field of application of the container 2 or the type of filling material 1, the density and/or the fill level of the filling material 1 in the container 2 must be determined. For this purpose, a measuring system based on radiometry is arranged on the container 2. In this case, the measuring system comprises a radiation source 10, a detector unit 12 and an evaluation unit 13 downstream of the detector unit 12. The radiation source 10 is located in a radiation protection container 11, which, in the open state, allows the radiation of the radiation source 10 to exit along a defined beam axis a.

[0030] In order to measure the density or fill level, the radiation protection container 11 and the detector unit 12 are arranged in such a way that the beam axis a of the radiation protection container 11 is directed towards the filling material 1. Furthermore, the detector unit 12 is arranged opposite the radiation protection container 11 in relation to the container 2, in such a way that the detector unit 12 is arranged as centrally as possible in the beam axis a of the radiation source 10, in order to detect the intensity of the radiation after passage through the filling material 1. For this purpose, the radiation protection container 11 and the detector unit 12 can either be mounted directly on the container 2, or indirectly on correspondingly free-standing stands. Based on this radiation intensity determined indirectly by scintillator, the evaluation unit 13 can determine the density or the fill level depending on the requirement, for example after corresponding calibration on the container 2.

[0031] Depending on the application, the radiometric measuring system is to be designed to be fire-proof for measuring operation, as is specified for example in the IEC 62598:2011 standard series. A possibility according to the invention for producing the radiation protection container 11 with little effort, without having to resort to fire-resistant tungsten as the manufacturing material, is therefore explained in more detail with reference to FIG. 2 and FIG. 3:

[0032] The radiation protection container 11, shown there, for the radiation source 10 or for an insert 3 in which the radiation source 10 is embedded is based on two cuboidal base bodies 110, 111, of which only the first base body 110 is shown in FIG. 2 for the sake of clarity. Both main bodies 110, 111 each have a first surface 1101 or a second surface 1111, wherein the surfaces 1101, 1111, with the exception of a radiation waveguide 113 and with the exception of radiation absorption structures 114, 114, 114, are formed in a planar manner in each case. In this case, the planar surfaces 1101, 1111 in the embodiment shown are each formed from one of the side surfaces of the cuboid.

[0033] FIG. 3 is a cross-sectional view of the radiation protection container 11, which extends orthogonally to the axis a of the radiation waveguide 113 and at the level between the first absorption structure 114 and the first end region 1130: As is clear from this, the base bodies 110, 111 are fastened to one another, in the finished state of the radiation protection container 11, in such a way that the predominantly planar surfaces 1101, 1111, with the exception of the radiation waveguide 113, adjoin one another in a form-fitting manner, within the scope of the manufacturing tolerances, such that the planar regions span a correspondingly planar plane E. Since the base bodies 110, 111 can be manufactured from steel, they can be welded, for example along the edges of the surfaces 1101, 1111, in order to form the radiation protection container 11. However, it is also conceivable to connect the base bodies 110, 111 by means of a 14 screw connection. As is indicated in FIG. 2, the base bodies 110, 111 can be provided, for this purpose, with four screw passages or four internal threads in each case, extending orthogonally to the plane E, wherein the passages of one base body 110, 111 in this case are intended to be arranged congruently with respect to the passages or internal threads of the other base body 110, 111.

[0034] Within the assembled radiation protection container 11, the radiation waveguide 113 is formed of opposite, mirror-symmetrically formed depressions in the surfaces 1101, 1111 of the base bodies 110, 111, in such a way that the radiation waveguide 113 extends within the plane E, from a first open end region 1130 on the cuboid to an opposite end region 1131 of the cuboid.

[0035] In the embodiment shown in FIG. 2 or FIG. 3, the depressions of the radiation waveguide 113 have a rectangular cross section, such that the resulting radiation waveguide 113 likewise has a rectangular cross section. In contrast to this illustration shown, it is alternatively also conceivable for the radiation waveguide 113 to have a round cross section, for which purpose the corresponding depressions have a semicircular cross section in each case. As an alternative to the variant shown, it is also conceivable for the radiation waveguide 113 to be formed only by a depression in one of the two surfaces 1101, 1111. Regardless of the cross-sectional shape of the radiation waveguide 113, the radiation waveguide 113 can be designed for improved beam focusing, such that the radiation waveguide 113 widens towards the second end region 1131, as is shown in FIG. 2. The depression(s) for the radiation waveguide 113 can be formed, for example, by subsequent machining of the surfaces 1101, 1111 by means of corresponding machining methods.

[0036] Moreover, in the region of the radiation absorption structures 114, 114, 114, the surfaces 1101, 1111 adjoin one another in a form-fitting manner after connection of the two base bodies 110, 111 in the tolerance range of the corresponding manufacturing method, since the radiation absorption structures 114, 114, 114 are formed of corresponding elevations in one of the two surfaces 1101 and corresponding depressions in the other surface 1101 in each case. As can be seen in FIG. 3, the elevations of the radiation absorption structures 114, 114, 114 in the embodiment shown are located in the first surface 1101 or in the first base body 110, wherein the second base body 111 has the depressions corresponding thereto in the second surface 1111, as can be seen from FIG. 3.

[0037] The variant of the radiation protection container 11 shown in FIG. 2 and FIG. 3 comprises three radiation absorption structures 114, 114, 114, which are arranged along the beam axis a at increasing distance from the first end region 1130 in each case. In this case, the shape which the radiation absorption structures 114, 114, 114 form in the plane E is shown in FIG. 2: Accordingly, the radiation absorption structures 114, 114, 114 proceed orthogonally from the beam axis a on both sides in the plane E, wherein the radiation absorption structures 114, 114, 114 curve in the shape of a circular segment towards the first end region 1130 with increasing distance from the beam axis a. In this case, the radiation absorption structure 114 which is arranged closest to the first end region 1130, and the middle radiation absorption structure 114, are each curved by 90. The radiation absorption structure 114 which is arranged closest to the second end region 1131 has a curvature of approximately 30 towards the first end region 1130.

[0038] As a result of this design, as soon as the radiation source 10 is attached to the first end region 1130, the radiation absorption structures 114, 114, 114 prevent a lateral radiation exit from the radiation protection container 11 along the plane E, even if possible tolerances in the manufacture or during connection of the base bodies 110, 111 lead to a lack of form-fitting engagement between the surfaces 1101, 1111. The depressions and elevations for the radiation absorption structures 114, 114, 114 can again be formed, for example, by machining the surfaces 1101, 1111 by means of corresponding machining methods, before the base bodies 110, 111 are connected.

[0039] As shown in FIG. 2, in the variant there the radiation source 10 is enclosed in a rotary insert 3 for fastening to the first end region 1130. In this case, the insert 3 is designed in such a way that the radiation source 10 within the insert 3 is shielded on all sides by a tungsten-based sheathing 101, except for an opening towards the first end region 1130 of the radiation waveguide 113. In this case, the term opening is also understood, in this connection, to mean a region lined with a corresponding material, which can be penetrated by the radiation of the radiation source 10 with low loss, for example 1.5 mm thick steel.

[0040] The rotary insert 3 and the base bodies 110, 111 are designed having a corresponding screw connection 14, in order to be able to screw the rotary insert 3 onto the radiation protection container 11 in such a way that the opening of the radiation source 10 within the rotary insert 3 adjoins the first end region 1130 of the radiation waveguide 113. For this purpose, the radiation source 10 is arranged within the rotary insert 3 on the thread axis of the screw connection 14. In addition, the screw connection 14 is designed such that its thread axis extends congruently to the beam axis a of the radiation waveguide 113. As a result, the radiation source 10 is automatically also located in the beam axis a of the radiation waveguide 113, in the mounted state, such that the radiation source 10 radiatesexclusivelyvia the second end region 1131 of the radiation waveguide, along its beam axis a.

[0041] In order to realize the screw connection 14, in the variant shown the rotary insert 3 comprises a corresponding external thread, wherein the base bodies 110, 111 form a corresponding internal thread. It is self-evident within the scope of the invention that the rotary insert 3, alternatively to the illustration shown, can also comprise the internal thread, and the radiation protection container 11 can comprise the external thread of the screw connection 14.

[0042] Since the thread axis of the screw thread 14, in the variant shown in FIG. 2, extends congruently with the beam axis a of the radiation waveguide 113, and the radiation source 10 is located within the rotary insert 3 on the thread axis of the screw thread 14, the radiation source 10 radiates automatically as soon as it is screwed on even incompletely. In contrast to this embodiment, a shutter function can be realized for transporting the radiation protection container 11, provided that the beam axis a of the radiation waveguide 113 extends in parallel with the thread axis of the screw thread 14, but with a defined radial offset. In order to realize the shutter function, in this case the radiation source 10 is also to be arranged within the rotary insert 3 having the same radial offset to the thread axis of the screw connection 14. As a result, the resulting shutter is only opened when the rotary insert 3 is screwed into the radiation protection container 11 exactly so far that the radiation source 10 is located in the beam axis a of the radiation waveguide 113. Optimally, the shutter function is implemented such that the shutter is open when the rotary insert 3 is screwed into the radiation protection container 11 up to a defined end stop. In order to prevent misuse or accidents in connection with the radiation source 10, the rotary insert 3 and the radiation protection container 11 can also be provided with a closing mechanism 4, by means of which the rotary insert 3 can be fixed in a position, on the radiation protection container 11, in which the shutter is closed, or in which the radiation source 10 is not located in the beam axis a of the radiation waveguide 113.

LIST OF REFERENCE SIGNS

[0043] 1 Filling material [0044] 2 Container [0045] 3 Rotary insert [0046] 4 Closing mechanism [0047] 10 Radioactive radiation source [0048] 11 Radiation protection container [0049] 12 Detector unit [0050] 13 Evaluation unit [0051] 14 Screw connection [0052] 101 Sheathing [0053] 110 First base body [0054] 111 Second base body [0055] 112 Connecting means [0056] 113 Radiation waveguide [0057] 114 Radiation absorption structure [0058] 1101 First surface [0059] 1111 Second surface [0060] 1130 First end region [0061] 1131 Second end region [0062] a Beam axis [0063] E Plane