Assembly of a field device
Patent Information
- Application Number
- EP2023740955
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-07-07
- Filing Date
- 2023-07-03
- Publication Date
- 2025-05-14
AI Technical Summary
Existing field device assemblies face complexity in achieving a reliable radial seal due to the need for precise manufacturing tolerances, making it challenging to maintain a pressure-bearing and media-resistant seal over a wide temperature range.
A field device assembly comprising a first component with a cylindrical bore and a second component featuring a mounting sleeve with an annular bead, where the cylindrical section of the sleeve has a clearance fit within the bore, creating a radially clamped seal through an interference fit, allowing for local deformation and forming a metal-metal seal that is pressure-bearing, media-resistant, and temperature-resistant.
The solution provides a reliable, efficient, and simplified method for achieving a radial seal in field devices, such as vortex counters and pressure measuring devices, ensuring effective sealing across varying temperatures and pressures while reducing manufacturing complexity.
Smart Images
Figure 1.1
Abstract
Description
[0001] Assembly of a field device
[0002] The present invention relates to an assembly of a field device.
[0003] Due to the manufacture of field devices in assemblies that are combined to form a complete device, it is necessary to provide pressure-retaining and media-resistant seals that are effective over a wide temperature range. Metal-to-metal seals, in which two metallic sealing surfaces are in contact with each other with a suitable surface pressure, are particularly suitable for this purpose. The published patent application DE 2011 264 discloses a sealing arrangement in which a cylindrical sleeve with a conical contour on the end face is axially compressed with a complementary cone to generate radial surface pressure against a cylindrical tube guided through the sleeve. This document is just one example of many in which the aim is always to achieve a radial seal through axial clamping.Although this works in principle, it is very complex, as several parts with tight manufacturing tolerances are required to achieve a defined radial sealing effect. Therefore, the object of the present invention is to remedy this situation.
[0004] The object is achieved according to the invention by the assembly according to independent patent claim 1 and the vortex meter according to independent patent claim 7.
[0005] The assembly of a field device according to the invention comprises a first component; and a second component, wherein the first component has a cylindrical bore, wherein the second component has a mounting sleeve with at least one first cylindrical portion which has a clearance fit with respect to the cylindrical bore of the first component, wherein the mounting sleeve has an annular circumferential bead around the at least one first cylindrical portion, which is formed monolithically with the at least one first cylindrical portion and which has an interference fit with respect to the cylindrical bore, wherein the at least one first cylindrical portion is inserted into the cylindrical bore with the circumferential bead, so that the at least one first cylindrical portion of the mounting sleeve is radially clamped in the cylindrical bore,whereby an annular circumferential radial seal is formed between the first component and the second component, wherein the interference fit is realized by at least local deformation of the at least one first cylindrical portion, in particular in the vicinity of the bead.
[0006] The area surrounding the bead includes in particular the areas of the sleeve that adjoin the bead in the axial direction on both sides
[0007] A field device within the meaning of the invention is, in particular, a measuring device in industrial process measurement technology for recording process variables, such as flow rate, flow velocity, fill level, pressure, temperature, density, viscosity, pH value, or other process variables. A measuring device for measuring the flow rate can, for example, comprise a vortex meter, a magnetic inductive flow meter, an ultrasonic flow meter, a thermal flow meter, or a Coriolis flow meter. Level measuring devices include, in particular, TDR measuring devices with free-radiating or guided microwaves or ultrasonic measuring devices. Pressure measuring devices comprise a pressure transducer whose measuring diaphragm can be subjected to a medium pressure directly or via a pressure transmitter. These measuring devices mentioned as examples, and others, can comprise assemblies according to the invention.
[0008] In a further development of the invention, the first component has a first axial stop surface, wherein the second component has a second axial stop surface which cooperates with the first axial stop surface in order to determine an axial position of the second component with respect to the first component.
[0009] In a further development of the invention, the at least one first cylindrical section is arranged in the axial direction over a coupling length in the cylindrical bore, wherein the coupling length is not less than half, for example not less than three-quarters and in particular not less than one time the diameter of the cylindrical bore.
[0010] In a further development of the invention, at a contact surface of the interference fit between the mounting sleeve and the bore, the average radial deformation of the mounting sleeve is at least twice, in particular at least four times, the radial deformation of the bore, and / or the maximum radial deformation of the mounting sleeve, in particular in the vicinity of the bead, is at least four times, in particular at least eight times, the radial deformation of the bore.
[0011] The mean radial deformation can be determined in particular by integrating the radial deformation over the volume of the body under consideration, over the axial area of the first cylindrical section divided by the integration volume.
[0012] In a further development of the invention, the mounting sleeve has plastic deformation in the region of the contact surface of the interference fit between the mounting sleeve and the bore and / or in the vicinity of the bead, wherein in particular the bore in the region of the contact surface has no plastic deformation.
[0013] In a further development of the invention, an axial length of the contact surface in the interference fit is not more than one fifth, in particular not more than one tenth, of the axial length of the at least one first cylindrical section.
[0014] The vortex meter according to the invention comprises: a measuring tube with a measuring tube casing which delimits a lumen for guiding a medium; a disruptive body in the lumen of the measuring tube for generating a vortex street; and an assembly according to one of the preceding claims, wherein the second component further comprises a paddle sensor, wherein the mounting sleeve has a first end face, wherein the mounting sleeve is arranged at least in sections in the bore with the first end face at the front, wherein the mounting sleeve has a second end face facing away from the first end face, and wherein the paddle sensor is arranged on the second end face; wherein the measuring tube casing has an opening downstream of the disruptive body in the flow direction, through which opening the paddle sensor projects into the lumen, wherein the first component is connected to the measuring tube casing along a contact surface which surrounds the mounting sleeve in an annular manner, in particular in a media-tight manner.
[0015] In a further development of the vortex meter according to the invention, the mounting sleeve has a second cylindrical section which adjoins the first cylindrical section in the direction of the second end face, wherein the second cylindrical section has a greater wall thickness than the first cylindrical section, wherein the second cylindrical section has an elastic membrane body on its end face facing away from the first end face, which carries the paddle sensor.
[0016] In a further development of the vortex meter according to the invention, the first component has a first axial stop surface, wherein the second component has a second axial stop surface which cooperates with the first axial stop surface in order to determine an axial position of the second component with respect to the first component, wherein a radial step facing the first end face between the first cylindrical section and the second cylindrical section forms the second axial stop surface.
[0017] In a further development of the vortex meter according to the invention, a sealing ring, in particular a graphite sealing ring, is clamped between a sealing surface of the measuring tube casing, which surrounds the opening in the measuring tube casing in a ring shape, and a sealing surface of the mounting sleeve facing away from the first end face of the mounting sleeve, which seal ring separates the lumen of the measuring tube from the first component.
[0018] In a further development, the vortex meter according to the invention further comprises an electromechanical transducer for detecting deflections of the paddle sensor and for providing deflection-dependent electrical primary signals, wherein the electromechanical transducer is arranged in the mounting sleeve.
[0019] In a further development, the vortex meter according to the invention further comprises an electronics housing; and a measuring and operating circuit for operating the electromechanical transducer and for detecting the primary electrical signals, wherein the electronics housing is held at a distance from the measuring tube by the first component, wherein the measuring and operating circuit is arranged in the electronics housing, and wherein an electrical connection runs through the first component, by which the measuring and operating circuit is connected to the electromechanical transducer.
[0020] The invention will now be explained in more detail with reference to the embodiments shown in the drawings.
[0021] It shows:
[0022] Fig. 1 : a view of an embodiment of an inventive
[0023] vortex counter;
[0024] Fig. 2a: a longitudinal section through an embodiment of an assembly according to the invention in a vortex meter; and
[0025] Fig. 2b: an enlarged detailed longitudinal section through a
[0026] Embodiment of an assembly according to the invention.
[0027] The embodiment of a vortex meter 1 shown in Fig. 1 comprises a measuring tube 2 with a substantially cylindrical measuring tube casing 21 which encloses a lumen 23 for guiding a medium. A particularly prismatic disruptive body 24 extends through the lumen 23 of the measuring tube 2 in order to narrow the clear cross-section of the measuring tube. Due to this cross-sectional narrowing, a vortex street is created in the flowing medium with a separation frequency of the vortices from the disruptive body 24 that is substantially proportional to the velocity. A paddle sensor 340 protrudes through an opening 25 in the casing body 21 of the measuring tube 2 into the lumen 23 downstream of the disruptive body 24 in order to detect the vortices.
[0028] Further details of the vortex meter and an assembly according to the invention for producing the vortex meter will now be explained with reference to Figs. 2a and 2b. The vortex meter further comprises an assembly 3, which is attached to the measuring tube 2 and comprises a first component 32 and a second component 34, each of which is monolithic in this case. The first component 32 comprises a flange 322 and a support tube 324 for supporting an electronics housing 40. The flange 322 bears against the measuring tube casing 21 with a mounting surface 326 and is fastened thereto by means of bolts 329 (shown only in Fig. 1). A cylindrical bore 328 extends through the first component 32 along a longitudinal axis of the support tube 324.
[0029] The second component 34 comprises the above-mentioned paddle sensor 340, an elastic annular membrane 342 and a mounting sleeve 343. The paddle sensor 340 comprises a shaft 341 which is connected to the inner edge of the annular membrane 342, to the outer edge of which the mounting sleeve 343 is connected. The mounting sleeve 343 comprises a first section 344 and a second section 345, wherein the second section is arranged between the annular membrane 342 and the first section 344. The second section 345 is designed as a rigid hollow cylinder which is connected to the annular membrane 342, the cylinder axis of which is perpendicular to a
[0030] 342, and which extends in relation to the annular membrane in the direction away from the paddle sensor 340. The first section 344 of the mounting sleeve 343, with essentially the same inner diameter, has a considerably smaller wall thickness than the second section 345, whereby the mounting sleeve
[0031] 343 has a radial jump on its outer surface at the transition between the first section 344 and the second section 345, which forms an annular, circumferential axial stop surface 346, which faces a first end face of the mounting sleeve 343 and faces away from the annular membrane 342 on the second end face of the mounting sleeve. The mounting sleeve 34 is inserted with its first section 344 into the bore 328, which extends through the first component 32, over a length L, wherein the cylindrical surface of the first section 344 of the mounting sleeve 343 has a clearance fit with the bore 328. An annular bead 348 runs around the surface of the first section 344 of the mounting sleeve 343 and has an interference fit with the bore 328. The contour of the bead 348 can, for example, be toroidal or spherical shell-shaped.By inserting the first section 344 of the mounting sleeve 343 into the bore 328, a metal-to-metal seal is formed between the first component 32 and the second component 34, which seal is particularly pressure-bearing. The mounting sleeve 343 is elastically and, if necessary, partially plastically deformed in the region of the first section 344, particularly in the vicinity of the bead.
[0032] The axial stop surface 346 between the first section 344 and the second section 345 of the mounting sleeve 343 rests against the mounting surface 326 of the flange 322 of the first component 32, whereby the second component is axially clamped in a blind hole 28 in the measuring tube casing 21, with the opening 25 in the measuring tube casing opening into the bottom of the blind hole 28. A sealing ring 27, in particular a graphite sealing ring, is axially clamped between the bottom of the blind hole 28 and the second end face of the mounting sleeve 343. Thus, the second component, which comprises the paddle sensor 340, is connected to the measuring tube casing in a defined position, in a temperature-resistant, media-resistant, vibration-resistant, and pressure-resistant manner.The metal-to-metal seal between the first component 32 and the second component 34 also reliably prevents medium from the lumen 23 of the measuring tube 2 from passing through the bore 328 of the support tube 324 into the electronics housing 40 in the event of the sealing ring 27 failing.
[0033] A measuring and operating circuit 42 for operating the vortex meter 1 is arranged in the electronics housing. This measuring and operating circuit is configured to evaluate the signals of an electromechanical transducer 44, which is arranged in the second component 34 and serves to detect the movements of the paddle sensor. The electromechanical transducer 44 can, in particular, be a capacitive, inductive, or resistive transducer, which is connected to the operating and evaluation circuit via a cable passing through the bore 328 of the support tube 324. Although the invention has been explained using a vortex meter and is particularly relevant here, it is also of interest for other field devices in which two components must be reliably connected to one another.
Claims
Patent claims 1. Assembly (3) of a field device, comprising a first component (32); and a second component (34), wherein the first component (32) has a cylindrical bore (328), wherein the second component (34) has a mounting sleeve (343) with at least one first cylindrical portion (344) which has a clearance fit with respect to the cylindrical bore (328) of the first component (32), wherein the mounting sleeve (343) has an annular circumferential bead (348) around the at least one first cylindrical section (344), which is formed monolithically with the at least one first cylindrical section (344) and which has an interference fit with respect to the cylindrical bore (328), wherein the at least one first cylindrical section (344) with the circumferential bead (348) is introduced into the cylindrical bore (328), so that the at least one first cylindrical section (344) of the mounting sleeve (343) is radially clamped in the cylindrical bore (328), whereby an annular circumferential radial seal is formed between the first component (32) and the second component (34), wherein the interference fit is realized with at least local deformation of the at least one first cylindrical section, in particular in the vicinity of the bead.
2. The assembly (3) according to claim 1, wherein the first component (32) has a first axial stop surface (326), and wherein the second component (34) has a second axial stop surface (346) that cooperates with the first axial stop surface to define an axial position of the second component (34) with respect to the first component (32).
3. Assembly (3) according to one of claims 1 or 2, wherein the at least one first cylindrical section (344) is arranged in the axial direction over a coupling length (L) in the cylindrical bore (328), wherein the coupling length (L) is not less than half, for example not less than three quarters and in particular not less than one times the diameter of the cylindrical bore (328).
4. Assembly (3) according to one of claims 1 to 3, wherein at a contact surface of the interference fit between the mounting sleeve (343) and the bore (328), the average radial deformation of the mounting sleeve (343) is at least twice, in particular at least four times, the radial deformation of the bore (328), and / or wherein the maximum radial deformation of the mounting sleeve (343), in particular in the vicinity of the bead, is at least four times, in particular at least eight times, the radial deformation of the bore (328).
5. Assembly (3) according to one of the preceding claims, the mounting sleeve (343) has plastic deformation in the region of the contact surface of the interference fit between the mounting sleeve (343) and the bore (328) and / or in the vicinity of the bead, and wherein in particular the bore (328) has no plastic deformation in the region of the contact surface.
6. Assembly (3) according to claim 4 or 5, wherein an axial length of the contact surface in the interference fit is not more than one fifth, in particular not more than one tenth, of the axial length of the at least one first cylindrical portion.
7. Vortex meter (1 ), comprising: a measuring tube (2) with a measuring tube jacket (21 ) which defines a lumen (23) for guiding a medium; a disruptive body (24) in the lumen (23) of the measuring tube (2) for generating a vortex street; and an assembly (3) according to one of the preceding claims, wherein the second component (34) further comprises a paddle sensor (340), wherein the mounting sleeve (343) has a first end face, wherein the mounting sleeve (343) is arranged at least in sections with the first end face forward in the bore (328), wherein the mounting sleeve (343) has a second end face facing away from the first end face, and wherein the paddle sensor (340) is arranged on the second end face; wherein the measuring tube casing (21), downstream of the disruptive body (24) in the flow direction, has an opening through which the paddle sensor (340) projects into the lumen, wherein the first component (32) is connected to the measuring tube casing (31) along a contact surface (326) surrounding the mounting sleeve (343) in an annular manner.
8. Vortex meter (1) according to claim 7, wherein the mounting sleeve (343) has a second cylindrical section (345) which adjoins the first cylindrical section (344) in the direction of the second end face, wherein the second cylindrical section (345) has a greater wall thickness than the first cylindrical section (344), wherein the second cylindrical section (345) has, on its end face facing away from the first end face, an elastic membrane body (342) which carries the paddle sensor (340).
9. Vortex meter (1 ) according to claim 7 with an assembly according to claim 2, wherein a radial step facing the first end face is arranged between the first cylindrical portion (344) and the second cylindrical portion (345) forms the second axial stop surface (346).
10. Vortex meter (1) according to one of claims 7 to 9, wherein a sealing ring (27), in particular a graphite sealing ring, is clamped between a sealing surface of the measuring tube casing (21), which surrounds the opening (25) in the measuring tube casing in a ring shape, and a sealing surface of the mounting sleeve facing away from the first end face of the mounting sleeve (343), which seal ring separates the lumen (23) of the measuring tube (2) from the first component (32).
11. Vortex meter (1) according to one of the preceding claims, further comprising an electromechanical transducer (44) for detecting deflections of the paddle sensor and for providing deflection-dependent electrical primary signals, wherein the electromechanical transducer (44) is arranged in the mounting sleeve (343).
12. Vortex meter (1) according to claim 10, further comprising an electronics housing (40); and a measuring and operating circuit (42) for operating the electromechanical transducer (44) and for detecting the primary electrical signals, wherein the electronics housing (40) is held at a distance from the measuring tube (2) by the first component (32), wherein the measuring and operating circuit (42) is arranged in the electronics housing (40), and wherein an electrical connection runs through the first component (32), by which electrical connection the measuring and operating circuit is connected to the electromechanical transducer.