Radiation protection containers for radiometric measuring instruments

Abstract

The invention relates to a safely handled radiation protection container (10) for mounting at least one radiation source (11) of a radiometric measuring system (1) in a dip tube (12) that extends vertically into a corresponding container (3) for measuring the density and / or fill level of a substance (2). The radiation protection container (10) is characterized by a guide arrangement (113), such as a pair of skids or a corresponding roller arrangement, which prevents rotation of the radiation protection container (10) about its longitudinal axis (a) when it is erected from the horizontal to the upright position. Erecting the radiation protection container (10) is thus made safer, since, according to the invention, it rolls over the guide arrangement (113) during erection, thereby preventing lateral tipping.In particular, in the case of a heavy radiation protection container (10) weighing over 500 kg, this significantly increases occupational safety.

Description

[0001] The invention relates to a radiation protection container for radiometric density or level measurement.

[0002] In process automation, measuring devices and systems are frequently used to record and / or control process variables. These variables include, among others, fill level, flow rate, pressure, temperature, pH value, redox potential, and conductivity. Depending on the specific process variable, different measuring principles are implemented in the measuring device or system. Actuators, such as valves or pumps, are used to control process variables by changing the flow rate of a liquid in a pipe section or the fill level in a container. The Endress+Hauser Group manufactures and distributes a wide range of such measuring devices and systems.

[0003] In the case of density or level measurements, measuring systems are often used whose method is based on radiometry. This method utilizes radioactive radiation (for example, gamma radiation from a cesium or cobalt source) emitted by one or more radioactive sources within the measuring system and passed through the container holding the material to be measured. After passing through the container, the transmitted radiation intensity is recorded by one or more radiation detectors within the measuring system. By evaluating the detector signal, the transmitted portion of the emitted radiation intensity is determined by a dedicated evaluation unit within the measuring system, and the density or level of the material is calculated based on this result.The transmitted portion of the radioactive radiation power cannot be detected directly after passing through the container. Instead, the radioactive radiation must first be converted into electromagnetic radiation in the optical spectral range by a suitable material before it can be detected by a photomultiplier (or alternatively, one or more avalanche photodiodes) within the radiation detector. Materials possessing this property are called scintillating materials. Polystyrene, among others, exhibits this scintillating property. Only the radiation in the optical spectral range can be detected by the photomultiplier or photodiode. Radiometric level or density measuring devices are already known in the art. The basic operating principle is described, for example, in patent EP 2 208 031 B1.

[0004] The radiation source(s) on the container can be mounted in two different ways: In the case of a single radiation source or detector, these can be positioned opposite each other on the outside of the container. However, particularly for level measurement or in the case of height-dependent density profiling, a corresponding number of radiation sources and detectors can also be used. In this case, one arrangement option is to position the radiation sources not on the outside of the container, but at different height levels inside a dip tube, which in turn extends vertically downwards from the top of the container into its interior.

[0005] In this design variant, the radiation sources are delivered using a specially designed radiation protection container and lowered into the immersion tube. Accordingly, the radiation protection container must be designed to completely shield the radiation sources during delivery. For this purpose, the container is based on a core made of lead or another radioactively sealing material. Furthermore, the container must be designed so that, after the container is attached to a suitable connection at the top of the immersion tube, such as a flange, the radiation sources can be lowered into it to the required height. This is achieved, for example, via a cable-based mechanism inside the container.

[0006] Depending on the required total radiation activity, the shielding body of the radiation protection container must be dimensioned accordingly. In practice, this results in a total weight of up to one ton for the radiation protection container, which must be taken into account during transport and attachment to the immersion tube. For this purpose, the radiation protection container is transported in a horizontal position on a suitable base, as this lowers the center of gravity sufficiently to prevent tipping. Following transport, the radiation protection container is placed on its connecting flange, which serves to attach it to the immersion tube, and finally lifted onto the tube and secured there. The connecting flange simultaneously forms the outlet of the interior from which the radiation sources are lowered into the immersion tube when the container is upright.Accordingly, once the radiation protection container is set up, its interior runs vertically, corresponding to the axis of the immersion tube, thus enabling the lowering of the radiation sources from the container into the immersion tube. A sealing mechanism on the container serves to create a radiation-tight seal at the connection point when the container is not attached to the immersion tube.

[0007] The radiation protection container is erected and lifted using a crane. For this purpose, one or more corresponding upper lifting points are provided on the radiation protection container. These are arranged relative to the connecting flange in the direction of the axis behind the center of gravity of the radiation protection container, in order to erect the container from its horizontal position onto the connecting flange. However, there is a risk that the container will tip over sideways, which poses a significant safety risk, especially with heavy radiation protection containers. The invention therefore aims to provide a radiation protection container that can be erected safely in this respect.

[0008] The invention solves this problem by providing the radiation protection container with a guide arrangement that prevents rotation of the container around its tube axis when it is lifted from a horizontal to an upright position. For this purpose, the guide arrangement can, for example, comprise a pair of skids, preferably parallel and / or convex, which run between the base and the connection. Lifting the radiation protection container at the upper stop point(s) is thus made safer, as the guide arrangement positions the container onto the connection flange.

[0009] The invention is explained in more detail using the following figures. They show: Fig. 1: A radiometric measuring system on a container, Fig. 2: a detailed view of the radiation protection container according to the invention, and Fig. 3: A schematic representation of how to set up the radiation protection container.

[0010] In Fig. Figure 1 shows a container 3 in which, for example, a reaction takes place as part of the oil refining process. Accordingly, the container 3 can contain crude oil or an intermediate product as fill material 2, which is not exclusively in liquid or gaseous form, but can also contain various solid phases, such as oil sludge, or impurities such as sand.

[0011] To locate the different phases of the fill material 2 in relation to the height of the container 3, a radiometric measuring system 1 is installed on the container 3. This system allows a density profile of the fill material 2 to be determined along its vertical path within the container 3. In the illustrated embodiment, the measuring system 1 comprises six radiation sources 2 arranged in a dip tube 12 inside the container 3. The radiation sources 11 are generally arranged at defined, different heights within the dip tube 12, thus covering the desired vertical measurement range for the density profile measurement.

[0012] Corresponding to each radiation source 11, a radiation detector 13 is arranged at approximately the same installation height on the outer wall of the container 3. The six individual radiation detectors 13 thus primarily measure the radiation intensity of the radioactive radiation transmitted from the associated radiation source 11 through the contents 2. The radiation intensity of the transmitted radiation depends on the density of the contents 2 and on whether the fill level in the container 3 has exceeded the corresponding height. Therefore, an evaluation unit of the measuring system (not explicitly shown) can determine the respective density of the contents 2 based on the measured intensity of the transmitted radiation, depending on the height at which the corresponding radiation source 11 or radiation detector 13 is located. In conjunction with the known installation heights of the radiation sources 11 and 13, the system can then determine the density of the contents 2 as a function of the height at which the corresponding radiation source 11 or radiation detector 13 is located.In this case, the density profile over the vertical measuring range in the container 3 can be created using the radiation detectors 13, or the fill level of the filling material 2 in the container 3 can be determined.

[0013] Since the value ranges in which the densities of the individual phases lie are usually known from calibration measurements, the evaluation unit of the measuring system 1 can also determine the individual phases of the filling material 2 at the respective installation heights based on the measured densities, provided that the value ranges are stored in the evaluation unit, if the density or the phase is to be determined.

[0014] For the delivery and installation of the radiation sources 11 in the immersion tube 12, the radiation sources 11 are first placed in a radiation protection container 10 and subsequently attached to an upper connection 1100, such as a flange connection of the already installed immersion tube 12. After the radiation protection container 10 is attached there, the radiation sources 11 are lowered from it into the immersion tube 12 so that they can be positioned at the intended height in the immersion tube 12. For this purpose, the radiation protection container 10 includes, for example, a cable-based mechanism, so that the radiation sources 11 can be lowered vertically from a corresponding interior space 1101 in the radiation protection container 10 into the immersion tube 12 and retrieved from there.

[0015] As in Fig. As shown in Figure 2, the radiation protection container 10 is designed such that the interior space 1101 extends from the connection 1100 into the radiation protection container 10 along the extension of the pipe axis a. The pipe axis a, or the orientation of the interior space 1101 within the radiation protection container 10, is defined by its connection 1100. The connection 1100 also serves as an inlet and outlet through which the radiation sources 11 are lowered. The connection 1100 is typically designed as a flange. During the manufacture of the shielding radiation protection container 10, the interior space 1101 is created either by recesses during the casting of the lead- or steel-cast base body 110, or subsequently by milling or drilling the cast base body 110.

[0016] To prevent radiation from escaping via connection 1100 during transport of the radiation protection container 10, the interior 1101 of the radiation protection container 10 can be closed at connection 1100 by means of a suitable closure device 115, such as a gate valve. Since the radiation protection container 10 remains attached to the immersion tube 12 after its installation on the immersion tube 12 during the subsequent measurement operation of the radiometric measuring system 1, for example, to exchange or reposition the radiation sources 11 if necessary, connection 1100 simultaneously serves as a base for the radiation protection container 10 in this upright position on the immersion tube 12.

[0017] The weight of the radiation protection container 10 depends primarily on the total activity of the radiation sources 11 within the measuring system 1. Particularly with a large container 3 or a correspondingly large number of radiation sources 11, the shielding base 110 of the radiation protection container 10, made of lead and surrounding the interior 1101, must be dimensioned to such an extent that the total mass of the radiation protection container 10 can reach up to one ton. To ensure that the radiation protection container 10 can still be transported safely to the container 3, it is not transported upright, as it would be when attached to the immersion tube 11, but rather lying down on an integrated or separate base 111. This keeps the center of gravity S of the radiation protection container 10 sufficiently low, thus preventing any risk of it tipping over.

[0018] The image shows the horizontal position of the radiation protection container 10. Fig. 3 a). The axis a, along which the interior space 1101 is oriented, does not run vertically in this case, but horizontally.

[0019] After transport, the radiation protection container 10 is set up in order to lift it onto the immersion tube 12, as Fig. 3 b) and Fig. 3 c) is visualized as follows: For this purpose, the radiation protection container 10 comprises upper lifting points 112 at which the radiation protection container 10 can be lifted into an upright position by means of a crane, so that the radiation protection container 10 rests on the connection 1100. For this purpose, the upper lifting points 112 are arranged behind the center of gravity S of the radiation protection container 11 in relation to the connection 1100 on the side of the radiation protection container to the immersion tube 12. In the Fig. 2 or Fig. In the embodiment shown in Figure 3, the radiation protection container 10 comprises two upper anchor points 112, which are arranged opposite each other at the same height with respect to the pipe axis a on the base body 110. As shown in Figure 3, the radiation protection container 10 has two upper anchor points 112, which are arranged opposite each other at the same height with respect to the pipe axis a. Fig. As can be seen in Figure 2, the radiation protection container 10 comprises, in addition to the upper lifting points 112, two further lower lifting points 114, which are arranged opposite each other at the same height with respect to the pipe axis a on the base body 110, but in relation to the connection 1100 in front of the center of gravity S of the radiation protection container 10. This makes it possible to unload the radiation protection container 10 after transport or before erecting it in a horizontal position by simultaneously lifting it over all lifting points 112, 114.

[0020] Fig. Figure 3 b) shows the radiation protection container 10 during erection. This is hazardous insofar as the radiation protection container 10 can tip over during this process by beginning to rotate about the axis a. To prevent this, the radiation protection container 10 according to the invention comprises, during the erection process, a Fig. In the embodiment shown in Figure 2, a parallel-aligned and convexly shaped pair of skids 113 runs between the base assembly 111 and the connection 1100. The radiation protection container 10 rolls over these skids when being erected from the horizontal to the upright position, thus preventing any potential rotation of the radiation protection container 10 about the axis a. According to the invention, any other type of guide arrangement with the same technical effect can be used instead of the pair of skids 113, such as appropriately arranged rollers over which the radiation protection container 10 rolls when being erected. Reference symbol list 1 Radiometric measuring system 2 Filling material 3 containers 10 radiation protection containers 11 radiation sources 12 dip tube 13 Radiation detector 110 basic bodies 111 Base arrangement 112 Upper attachment points 113 Leadership Order 114 Lower anchor points 115 Closure arrangement 1100 connection 1101 Interior a pipe axis S focus QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 2 208 031 B1

[0003]

Claims

[1] Radiation protection container (10) for mounting at least one radiation source (11) of a radiometric measuring system (1) in a dip tube (12) which extends vertically into a corresponding container (3) for measuring the density and / or level of a filling material (2), comprising: - A shielding base body (110), with ◯ a connection (1100) corresponding to the immersion tube (12), which defines a corresponding tube axis (a) and forms a corresponding base for the radiation protection container (10) for an erected position, ◯ an interior space (1101) which, starting from the connection (1100), is formed along the tube axis (a) in such a way that the at least one radiation source (11) can be lowered through the connection (1100) from the interior space (1101) or picked up from there, - a base arrangement (111) by means of which the radiation protection container (11) can be stored lying down so that its center of gravity (S) is lower than in the erected position, - at least one upper attachment point (112) which is arranged behind the center of gravity (S) of the radiation protection container (11) in relation to the connection (1100) in order to place the radiation protection container (11) from the lying position onto the connection (1100) in such a way that the tube axis (a) is vertical, characterized by - a guide arrangement (113) by means of which rotation of the radiation protection container (10) about the immersion tube axis (a) is prevented when erecting it from the lying to the erected position. [2] Radiation protection container (11) according to claim 1, wherein the guide arrangement (113) comprises a pair of runners, in particular aligned parallel and / or convexly shaped, which runs between the base arrangement (111) and the connection (1100). [3] Radiation protection container according to claim 1 or 2, wherein the guide arrangement (113) comprises at least one roller. [4] Radiation protection container according to claims 1 to 3, comprising: - two upper stop points (112) which are arranged opposite each other on the base body (110) at the same height in relation to the tube axis (a). [5] Radiation protection container according to claims 1 to 4, comprising: - two lower attachment points (114), which ◯ in relation to the connection (1100) in front of the centre of gravity (S) of the source container (11) and ◯ are arranged opposite one another on the base body (110) at the same height with respect to the axis (a). [6] Radiation protection container according to one of the preceding claims, wherein the connection (1100) is designed as a flange. [7] Radiation protection container according to one of the preceding claims, which has a weight of at least 0.5 T. [8] Measuring system (1) for the radiometric determination of the density and / or fill level of a filling material (2) in a container (3), comprising: - A dip tube (12) extending vertically into the container (3) with an upper connection (1100), - a radiation protection container (11) according to one of the preceding claims, which can be fastened to the immersion tube (12) via the connection (1100), - at least one radioactive radiation source (10) which can be lowered from the interior (1101) of the radiation protection container (11) into the immersion tube (12) or picked up from there, - at least one radiation detector (13) which, in the lowered state, is arranged outside the container (3) in particular at the same height as the radiation source (10) such that a radiation intensity of the radiation source (10) can be detected after irradiating the filling material (2), and - an evaluation unit designed to determine the density and / or fill level of the filling material (2) in the container (3) based on the received radiation intensity. [9] Measuring system (1) according to claim 8, comprising: - a plurality of radiation sources (10) which, in the lowered state, are arranged one below the other in the immersion tube (12), and - a corresponding number of radiation detectors (13) arranged at corresponding heights outside the container (3). [10] Method for erecting the radiation protection container according to one of claims 1 to 7 from the lying position (a), comprising the following method step: - Lifting the radiation protection container (10) at the at least one upper attachment point (112) so that the radiation protection container (10) is placed on the connecting flange (1100) via the guide arrangement (113) (c).

Images