Weld-in adapter for connecting a sensor or actuator to a container, and arrangement with such a weld-in adapter.

Description

[0001] The invention relates to a weld-in adapter for connecting a sensor or actuator to a container containing a medium according to the preamble of claim 1, and to an arrangement comprising a sensor or actuator and a container with a weld-in adapter according to the preamble of claim 8.

[0002] Weld-in adapters are generally well-known. They have proven particularly useful in process measurement technology for attaching various sensors and measuring devices for detecting pressure, temperature, flow, fill levels, etc., as well as actuators, to or within a container, such as a pipeline or tank.

[0003] One requirement is to integrate the sensors and actuators into the container in such a way that the respective device, i.e., the sensor or actuator, has a seamless transition with the inner wall of the container, while still allowing it to be removed for service or replacement in case of damage or repair. For this purpose, weld-in adapters are used, particularly in the process industry. These are preferably shaped as quasi-disc-like components and have a through-hole into which a sensor or actuator, usually cylindrical or rotationally symmetrical, is screwed or clamped with its end face. The sensor / actuator is typically secured in the weld-in adapter via a thread or a rear clamping mechanism using a union screw, perforated plate, or clip.

[0004] Typically, when installing the sensor / actuator, care must be taken to ensure a tight connection between the sensor / actuator and the weld-in adapter. For this purpose, the weld-in adapter has a sealing edge at the process- or medium-side end of the through-hole, in the form of a tapered section that compresses a seal, preferably an O-ring, located there.

[0005] Understandably, the sensor or actuator must be inserted into the through-hole within specified and very tight tolerances to ensure the required tightness and functionality under the given conditions. Therefore, the welding process during the installation of the adapter into the container wall presents a particular challenge, as the components are melted at the weld point, resulting in extreme thermal stresses on the joining partners. This can lead to the development of significant local stress concentrations, which are transferred from the weld seam to or introduced into these components. Whether and to what extent these stresses lead to partial deformations of the joining partners depends, among other things, on their materials, the internal stress in the components (due to possible pre-deformation), and the weld seam design (e.g.,...).pulsed or unpulsed), from the set welding current, the energy input, the welding material added, the speed and the welding process itself, as well as many other influencing factors that are usually not foreseen by the manufacturer or supplier of the two components, let alone influenced on site.

[0006] German patent DE 10 2019 126381 A1 discloses a hygienic adapter solution for field devices, in particular for avoiding dead spaces and for easy cleaning. The solution consists of a two-part adapter with a connecting adapter and a container adapter.

[0007] US patent 2016 / 025575 A1 discloses an adapter for measuring a physical variable in which a temperature difference between a protective tube for a temperature sensor and a flange plate is used to create a sealing press fit.

[0008] DE 10 2020 113929 A1 discloses a pipe section of a measuring tube with a longitudinally extended recess and an installation device designed as an adapter with a through-hole. The underside of the adapter has a partially cylindrical recess.

[0009] US 6059254 A discloses a mounting device for process instruments. The device consists of an outer and an inner housing separated by a space. This space serves to thermally decouple the instrument from the process to improve measurement accuracy and minimize the effects of temperature fluctuations. The mounting device is intended to reduce the effects of thermal distortion and vibration.

[0010] EP 2 270 320 A2 describes a probe fitting for a measuring probe, manufactured in one piece from a sheet of metal. The fitting consists of an inner sleeve for receiving the measuring probe and an outer sleeve for mounting, which are connected by a connecting web and radially spaced. An annular gap between the inner and outer sleeves is intended to largely prevent heat distortion of the inner sleeve during welding of the outer sleeve.

[0011] The object of the invention is to simplify the installation of a weld-in adapter into the wall of a container in such a way that the thermal influence on the tightness of the connection between the weld-in adapter and a sensor or actuator inserted into it, which is caused by the welding process, is reduced or completely eliminated even under worst-case conditions during the welding process.

[0012] This problem is solved according to the invention with a weld-in adapter having the features of claim 1 and an arrangement having the features of claim 8. Advantageous embodiments of the invention are specified in the dependent claims.

[0013] The core of the invention lies in the realization that, to compensate for the thermal effects resulting from the welding process, the sealing edge of the weld-in adapter facing the medium, and thus the medium-side end face of the sensor or actuator, is offset from the outer edge region of the weld-in adapter, where the weld is made, by a distance relative to each other. This means that the sealing edge of the weld-in adapter, and therefore the end face of the sensor or actuator, protrudes or is recessed relative to the inside of the container; in any case, it is not coplanar. Crucially, to compensate for this parallel offset, the transition area of ​​the weld-in adapter, which acts as a connecting element between the outer edge region and the sealing edge, has a curved structure with an angle of inclination α.

[0014] This curved structure effectively creates several joints, giving the transition area a degree of flexibility. This allows the resulting pressure or tensile forces in the weld-in adapter to change under strong thermal influences, leading to a change in the angle of attack α. Consequently, the distance between the sealing edge of the weld-in adapter and its outer edge, where the weld is made, also changes. The forces acting horizontally in the container wall are redirected vertically by 90° by this inventive design, where they can dissipate in a range that is completely uncritical from a metrological perspective.As a result of this movement, any mechanical stresses that occur are easily dissipated in such a way that they do not cause any functional impairment from a metrological perspective, while the connection point between the weld-in adapter and the sensor / actuator is mechanically relieved and decoupled. The focus here is particularly on the sealing edge and the threaded connection between the sensor / actuator and the weld-in adapter.

[0015] Preferably, the transition area in the region of the curved structure has a thinner wall than at its outer edge. This optimizes the flexibility of the transition area and thus the desired movement during thermal stress.

[0016] Preferably, the angle of attack α in the raised embodiment is chosen to be large enough to optimize the joint functionality and thus the compensation effect. An optimum between the necessary mobility during the welding process and the required stability and rigidity has been achieved at an angle between 30° and 40°, particularly preferably between 32° and 36° in the embodiment where the sealing edge projects towards the outer edge region or the inside of the container, and between 40° and 50°, particularly preferably 45° in the embodiment where the sealing edge is recessed towards the outer edge region or the inside of the container, although the invention is not limited to these specifications.

[0017] It is further preferred that the weld-in adapter is suitable for flush mounting of the sensor or actuator.

[0018] The invention will now be explained in more detail using exemplary embodiments and with reference to the drawings.

[0019] They show schematically: Figure 1 shows a container in the form of a tank with a sensor; Figure 2 shows a sectional view of a weld-in adapter according to a first embodiment with a sensor installed in a container wall; Figure 3 shows a perspective view of a weld-in adapter according to the invention. Fig. 2 Figure 4 shows a sectional view of a weld-in adapter according to a second embodiment with a sensor installed in a container wall, and Figure 5 shows a perspective view of a weld-in adapter according to the invention. Fig. 4 .

[0020] In the following description of preferred embodiments, identical reference numerals denote identical or comparable components.

[0021] Figure 1Figure 1 schematically illustrates how a sensor 1 is arranged in or on a container 2 by means of a weld-in adapter 3. In this example, the container 2 is depicted as a tank. Naturally, all possible container shapes, including piping systems, as commonly used in process engineering, are suitable. In this embodiment, the sensor 1 is designed as a pressure sensor intended for measuring the hydrostatic pressure to determine the fill level in the tank.

[0022] In Figure 2 and Figure 3 The weld-in adapter 3 according to the invention is shown in a first embodiment, which is characterized in that the sealing edge 5 protrudes towards an outer edge region 3b of the flexible transition region 3a or the inside of the container 2a. Fig. 2 shows schematically how this weld-in adapter 3 is installed in the wall of the container 2.

[0023] In Figure 4 and Figure 5The weld-in adapter 3 according to the invention is shown in a second embodiment, which is characterized in that the sealing edge 5 is set back from the outer edge region 3b of the flexible transition region 3a or the inside of the container 2a. Fig. 4 shows schematically how this weld-in adapter 3 is installed in the wall of the container 2.

[0024] Since all other essential elements are similar in both embodiments, the following description refers to all four. Figures 2 to 5 .

[0025] The weld-in adapter 3 initially has a through-opening 4 into which a sensor 1 is screwed. Here, the sensor 1 is not shown in its entirety, but only the process connection, which, in the case of a pressure sensor, contains the pressure measuring cell and through which the sensor 1 is firmly connected to the weld-in adapter 3. In the illustrated embodiments, the sensor 1 is installed flush with the front of the weld-in adapter 3.

[0026] At the process-side or medium-side end of the through-opening 4, a sealing edge 5 is arranged in the form of a taper of the through-opening 4. Many sealing concepts are known and their implementation is conceivable. Here, it is shown that the sensor 1, or rather its process connection, has a circumferential groove at the front corner facing the inside of the container 2a, in which a seal 7, preferably an O-ring, is inserted. In contrast, the weld-in adapter 3 has the aforementioned sealing edge 5, whereby the O-ring is compressed into the weld-in adapter 3 during the screw-in process of the sensor 1, thus creating a reliable seal between the two parts.

[0027] The flexible transition area 3a is arranged concentrically around the sealing edge 5, the outer edge area 3b of which is connected to the container 2 by means of a welded connection 6.

[0028] A key feature of the weld-in adapter 3 is that the sealing edge 5 of the weld-in adapter 3 facing the medium, and thus the medium-side end face of the sensor 1 or actuator, is parallel to the outer edge region 3b of the weld-in adapter 3, where the weld joint 6 is made. To compensate for this parallel offset, the flexible transition region 3a of the weld-in adapter 3, which acts as a connecting element between the outer circumferential side 3b and the sealing edge 5, has a curved structure with an angle of attack α. This curved structure effectively creates several joints, so that under strong thermal influences resulting from a welding process, the pressure or tensile forces in the container wall cause a change in the angle of attack α.Accordingly, the distance between the sealing edge 5 of the weld-in adapter 3 and the inside of the container 2a changes. This movement redirects any mechanical stresses into an upward or downward movement of the sensor 1, thus relieving and decoupling the sensitive sealing area and the threaded connection between the sensor 1 or actuator and the weld-in adapter 3.

[0029] Advantageously, in the embodiment in Fig. 2 The angle of attack α is chosen to be large enough to ensure optimal joint functionality and thus optimal compensation, thereby achieving an optimum balance between the necessary mobility during the welding process and the required stability and rigidity. An advantageous value is found in the embodiment according to... Figs. 2 and 3, if the parallel offset between sealing edge 5 and edge area 3b is approximately 6-7 mm, between 30° and 40°, particularly preferably between 32° and 36°, and in the embodiment according to Figs. 4 and 5 , if the parallel offset between sealing edge 5 and edge area 3b is approximately 4-5 mm, between 40° and 50°, particularly preferably at 45°, the invention is not limited to these specifications. Reference symbol list

[0030] 1 Sensor 2 Container 2a Container inside 2b Container outside 3 Weld-in adapter 3a Transition area 3b Outer edge of the transition area 4 Through opening 5 Sealing edge 6 Weld point 7 Seal

Claims

1. Weld-in adapter for connecting a sensor (1) or actuator to a container (2) containing a medium, comprising a cylindrical through-opening (4) for receiving the sensor (1) or actuator and a transition region (3a) arranged concentrically around the through-opening (4), the outer edge region (3b) of which transition region is suitable for welding (6) to the container (2), the through-opening (4) having, at one end, a circumferential sealing edge (5) which tapers the through-opening (4) and which is suitable as part of a sealing concept for the media-tight connection of the sensor (1) or actuator to the weld-in adapter (3), characterized in that the sealing edge (5) is parallel to the outer edge region (3b) of the transition region (3a), the sealing edge (5) is offset in relation to the outer edge region (3b) of the transition region (3a) by a distance, and the transition region (3a), which is located as a connecting element between the outer edge region (3b) and the sealing edge (5), has a curved structure with a pitch angle α to compensate for this offset.

2. Weld-in adapter according to claim 1, characterized in that the sealing edge (5) protrudes in relation to the outer edge region (3b) of the transition region (3a).

3. Weld-in adapter according to claim 1, characterized in that the sealing edge (5) is set back in relation to the outer edge region (3b) of the transition region (3a).

4. Weld-in adapter according to any of the preceding claims, characterized in that the transition region (3a) has a lesser wall thickness in the region of the curved structure than at the outer edge region (3b) of the transition region.

5. Weld-in adapter according to any of the preceding claims, characterized in that the weld-in adapter (3) is suitable for flush mounting of the sensor (1) or actuator.

6. Weld-in adapter according to any of the preceding claims, characterized in that the pitch angle α is between 30° and 50°.

7. Weld-in adapter according to any of the preceding claims, characterized in that the face facing the container inner face (2a) comprises a surface structure which allows the weld-in adapter (3) to be used in hygienic applications.

8. Arrangement consisting of a sensor (1) or actuator and a container (2) containing a medium, the sensor (1) or actuator being suitable for insertion into the container (2) and the container (2) having, for receiving the sensor (1) or actuator, an opening in its wall and a weld-in adapter (3) arranged therein, characterized in that the weld-in adapter (3) is designed according to any of the preceding claims.