Radioprotective container for radiometric measuring devices

Abstract

The invention relates to a safely handleable radioprotective container (10) for mounting at least one radiation source (11) of a radiometric measuring system (1) in an immersion tube (12), which is to be used to measure density and / or fill level of a filling material (2) and for this purpose extends vertically into a corresponding filling material container (3). In this case, the radioprotective container (10) is distinguished by a guide arrangement (113), such as a pair of runners or a corresponding roller arrangement, as a result of which a rotation of the radioprotective container (10) about the longitudinal axis (a) thereof is prevented in the course of setting upright from the horizontal position to the set-up position. The setting upright of the radioprotective container (10) becomes correspondingly safer since in the course of setting up, according to the invention, the container rolls via the guide arrangement (113), as a result of which lateral tilting is prevented. Particularly in the case of a heavy radioprotective container (10) having a weight of more than 500 kg, this considerably increases safety at work.

Description

[0001] Radiation protection containers for radiometric measuring instruments

[0002] The invention relates to a radiation protection container for radiometric density or level measurement.

[0003] In process automation, measuring devices and measuring systems are often used to record and / or influence process variables. Process variables measured include, among others, fill level, flow, pressure, temperature, pH value, redox potential, or conductivity. Depending on the process variable, different measuring principles are implemented in the measuring device or measuring system. Actuators, such as valves or pumps, are used to influence process variables; these can be used to change the flow of a liquid in a pipe section or the fill level in a container. A wide range of such measuring devices and measuring systems are manufactured and distributed by the Endress + Hauser Group.

[0004] In the case of density or level measurements, measuring systems are often used whose measuring method is based on radiometry. This measuring method uses radioactive radiation (e.g., gamma radiation from a cesium or cobalt source) emitted by one or more radioactive radiation sources of the measuring system and passed through the container containing the product to be measured. After passing through the container, the transmitted radiation intensity is recorded by one or more radiation detectors of the measuring system. By evaluating the detector signal, the transmitted portion of the emitted radiation intensity is determined by a specially designed evaluation unit of the measuring system, and based on this, the density or level of the product is determined.The transmitted portion of the radioactive radiation cannot be directly detected 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 the radiation can be detected by a photomultiplier (or alternatively, one or more avalanche photodiodes) within the radiation detector. Materials that exhibit this property are called scintillating materials. Polystyrene, among others, exhibits this scintillating property. Only radiation in the optical spectral range can be detected by the photomultiplier or photodiode. Radiometric level or density measuring devices are already known from the prior art. The basic operating principle is described, for example, in patent EP 2 208 031 B1.

[0005] The radiation source(s) can be mounted on the container in two different ways: In the case of a single radiation source or a single radiation detector, these can be arranged opposite each other on the outside of the container. However, a corresponding plurality of radiation sources and radiation detectors can also be provided, particularly for level measurement or in the case of height-dependent density profile measurement. In this case, one arrangement variant involves arranging the radiation sources not on the outside of the container, but at different heights within a dip tube, which in turn extends vertically downwards from the top of the container into the interior.

[0006] In such a design variant, the radiation sources are delivered in a specifically designed radiation protection container and lowered into the immersion tube. Accordingly, the radiation protection container must be designed to ensure that the radiation sources are completely shielded during delivery. To this end, the radiation protection container consists of a base made of lead or another radioactively sealing material. Furthermore, the radiation protection container must be designed so that the radiation sources can be lowered to the required height after attaching the radiation protection container to a suitable connection at the top of the immersion tube, such as a flange. This is achieved, for example, via a rope-based mechanism within the radiation protection container.

[0007] The shielding base body of the radiation protection container must be dimensioned accordingly depending on the required total radiation activity. In practice, this results in a total weight of the radiation protection container of up to one ton, which must be taken into account with regard to transport and attachment to the immersion tube. For this purpose, the radiation protection container is transported in a lying position on a suitable base arrangement, as this ensures that the center of gravity of the radiation protection container is low enough that there is no risk of tipping over. Following transport, the radiation protection container is placed on its connecting flange, which is used to attach it to the immersion tube, and then lifted onto the immersion tube or fastened there. The connecting flange also forms the exit of the interior space from which the radiation sources are lowered into the immersion tube when the container is in its upright position.Accordingly, once the radiation protection container is installed, the interior runs vertically, corresponding to the axis of the immersion tube, allowing the radiation sources to be lowered from the radiation protection container into the immersion tube. A locking device on the radiation protection container serves to seal the interior radiation-safely against radiation as long as the radiation protection container is not installed on the immersion tube.

[0008] The radiation protection container is erected and lifted using a crane. For this purpose, one or more corresponding upper attachment points are provided on the radiation protection container. These are arranged behind the center of gravity of the radiation protection container in the direction of the axis relative to the connection flange, in order to position the radiation protection container from a lying position onto the connection flange. However, this poses the risk of the container tipping sideways, which represents a corresponding safety risk, particularly with heavy radiation protection containers. The invention is therefore based on the object of providing a radiation protection container that can be safely erected in this respect.

[0009] The invention achieves this objective by providing the radiation protection container with a guide assembly that prevents rotation of the radiation protection container about the tube axis when erecting it from a lying position to an upright position. For this purpose, the guide assembly can, for example, comprise a pair of skids, particularly parallel and / or convexly shaped, that extend between the base assembly and the connection. This makes lifting the radiation protection container at the upper attachment point(s) more secure, since the radiation protection container is positioned on the connection flange via the guide assembly.

[0010] The invention is explained in more detail with reference to the following figures. Shown are:

[0011] Fig. 1 : A radiometric measuring system on a container,

[0012] Fig. 2: a detailed view of the radiation protection container according to the invention, and

[0013] Fig. 3: a schematic representation of the installation of the radiation protection container.

[0014] In Fig. 1, a container 3 is shown in which, for example, a reaction takes place as a process step within the oil refinery process.

[0015] Accordingly, the container 3 may contain crude oil or an intermediate product as filling material 2, which is not exclusively in liquid or gaseous form, but may also contain various solid phases, such as oil sludge, or impurities such as sand.

[0016] In order to be able to locate the various phases of the filling material 2 in relation to the height of the container 3, a radiometric measuring system 1 is installed on the container 3, by means of which a density profile of the filling material 2 can be determined along the vertical course in the container 3. For this purpose, the measuring system 1 in the illustrated embodiment comprises six radiation sources 2, which are arranged in an immersion tube 12 inside the container 3. The radiation sources 11 are generally arranged at defined, different heights in the immersion tube 12 so that the desired vertical measuring range of the density profile measurement is covered. 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.As a result, the six individual radiation detectors 13 primarily measure the radiation intensity of the radioactive radiation that is transmitted from the associated radiation source 11 through the filling material 2. The radiation intensity of the transmitted radiation depends on the density or on whether the fill level of the filling material 2 in the container 3 has exceeded the corresponding height. Thus, an evaluation unit of the measuring system (not explicitly shown) can use the measured intensity of the transmitted radiation to determine either the respective density of the filling material 2 depending on the height at which the corresponding radiation source 11 or the corresponding radiation detector 13 is arranged. In conjunction with the known installation heights of the radiation sources 11 orIn this case, the radiation detectors 13 can be used to create the density profile over the vertical measuring range in the container 3, or the fill level of the filling material 2 in the container 3 can be determined.

[0017] 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 use the measured densities to determine the individual phases of the filling material 2 at the respective installation heights, provided that the value ranges are stored in the evaluation unit, provided that the density or the phase is to be determined.

[0018] For delivery and installation of the radiation sources 11 in the immersion tube 12, the radiation sources 11 are in practice first housed in a radiation protection container 10 and then secured there to an upper connection 1100, such as a flange connection of the already installed immersion tube 12. After the radiation protection container 10 has been secured there, the radiation sources 11 are lowered therefrom into the immersion tube 12 in order to be positioned at the intended height in the immersion tube 12. For this purpose, the radiation protection container 10 comprises, for example, a rope-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 or picked up from there.

[0019] As shown in Fig. 2, the radiation protection container 10 is designed such that the interior space 1101 protrudes from the connection 1100 into the radiation protection container 10 in an extension of the tube axis a. The tube axis a, or the orientation of the interior space 1101 within the radiation protection container 10, is defined by its connection 1100.

[0020] At the same time, the connection 1100 functions as an outlet or inlet 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 by recesses during the casting of the lead- or cast-steel-based base body 110, or subsequently by milling or drilling the cast base body 110.

[0021] 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 toward connection 1100 by means of a suitable closure arrangement 115, such as a gate valve. Since the radiation protection container 10, after being attached to the immersion tube 12, remains attached to the immersion tube 12 during the subsequent measurement operation of the radiometric measurement system 1, for example, in order to replace or reposition the radiation sources 11 if necessary, the connection 1100 simultaneously serves as a base for the radiation protection container 10 in this installed position on the immersion tube 12.

[0022] 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 in the case of a large container 3 or a correspondingly large number of radiation sources 11, the shielding base body 110 of the radiation protection container 10 made of lead, which surrounds the interior 1101, must be dimensioned such that this results in a total mass of the radiation protection container 10 of up to one ton. To ensure that the radiation protection container 10 can nevertheless be safely transported to the container 3, it is not transported in an upright state, as is the case when attached to the immersion tube 11, but rather lying on an integrated or separate base arrangement 111. This ensures that the center of gravity S of the radiation protection container 10 is correspondingly low, so that there is no danger of tipping over.

[0023] The horizontal state of the radiation protection container 10 is visualized in Fig. 3 a). The axis a, along which the interior space 1101 is aligned, runs horizontally in this case, rather than vertically.

[0024] After transport, the radiation protection container 10 is set up in order to lift it onto the immersion tube 12, as shown in Fig. 3 b) and Fig. 3 c): For this purpose, the radiation protection container 10 comprises upper attachment 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 stands on the connection 1100. For this purpose, the upper attachment points 112 are arranged behind the center of gravity S of the radiation protection container 11 in relation to the radiation protection container-side connection 1100 to the immersion tube 12. In the embodiment shown in Fig. 2 and Fig. 3, the radiation protection container 10 comprises two upper attachment points 112, which are arranged opposite one another on the base body 110 at the same height with respect to the tube axis a. As can be seen from Fig.2, the radiation protection container 10 comprises, in addition to the upper attachment points 112, two further, lower attachment points 114, which in turn are arranged opposite one another on the base body 110 at the same height with respect to the pipe axis a, but in front of the center of gravity S of the radiation protection container 10 with respect to the connection 1100. This makes it possible to unload the radiation protection container 10 in a lying position after transport or before erecting it, while simultaneously lifting it over all attachment points 112, 114.

[0025] Fig. 3 b) shows the radiation protection container 10 during erection. This is hazardous in that the radiation protection container 10 may 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, in the embodiment shown in Fig. 2, comprises a parallel and convexly shaped pair of runners 113 that runs between the base arrangement 111 and the connection 1100. The radiation protection container 10 rolls over these runners during erection from the lying to the upright position, thus preventing any potential rotation of the radiation protection container 10 about the axis a. Within the meaning of the invention, any other type of guide arrangement with the same technical effect can be used instead of the pair of runners 113, such as, for example, appropriately arranged rollers over which the radiation protection container 10 rolls during erection.

[0026] List of reference symbols

[0027] 1 Radiometric measuring system

[0028] 2 Filling material

[0029] 3 containers

[0030] 10 radiation protection containers

[0031] 11 radiation sources

[0032] 12 dip tube

[0033] 13 radiation detector

[0034] 110 basic bodies

[0035] 111 Base arrangement

[0036] 112 Upper anchor points

[0037] 113 Guide arrangement

[0038] 114 Lower anchor points

[0039] 115 Locking arrangement

[0040] 1100 connection

[0041] 1101 Interior a tube axis

[0042] S focus

Claims

Patent claims 1. A radiation protection container (10) for mounting at least one radiation source (11) of a radiometric measuring system (1) in a dip tube (12) extending 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 o 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) in an erected position, o an interior space (1101) which, starting from the connection (1100), is formed along the tube axis (a) such 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) runs vertically, 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 are arranged o in front of the center of gravity (S) of the radiation protection container (11) with respect to the connection (1100) and o opposite one another at the same height with respect to the axis (a) on the base body (110).

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, when lowered, is located in particular at the same height as the radiation source (10) is arranged outside the container (3) in such a way that a radiation intensity of the radiation source (10) can be detected after radiating through 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. A 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).

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