FLOW MEASURING SYSTEM

Description

[0001] The invention relates to a flow measurement system for measuring a fluid flow in a fluid line, in particular in a high-pressure line, comprising: a housing having a fluid channel and defining a channel axis by the course of the fluid channel, and at least one ultrasonic probe which can be attached to the housing and which has a direction of emission, wherein a mounting stud is provided for attaching the ultrasonic probe to the housing, which is welded to the outer wall of the housing and which has a receptacle for the ultrasonic probe, wherein the direction of emission of the ultrasonic probe is inclined to the channel axis when the ultrasonic probe is arranged in the receptacle.

[0002] In many areas of engineering, measurements must be taken on flowing fluids, i.e., gases or liquids. For example, flow velocities of fluids in pipelines can be determined using ultrasonic measurement technology based on the differential time-of-flight method. Based on the determined flow velocity and the known cross-sectional area of ​​the pipeline, the volumetric flow rate of the fluid flowing through the pipeline can be calculated. Such volumetric flow measuring devices are frequently used in the form of meters to determine the delivery and / or consumption quantities of gases or liquids.

[0003] Due to the oblique orientation of the radiation direction relative to the channel axis, a measuring section with a component in or against the flow direction is created, which is important for determining the axial flow velocity. However, the oblique orientation of the ultrasonic probe poses a problem with regard to its mounting on the housing, especially if it needs to be able to withstand high pressure.

[0004] For example, a cylindrical mounting bracket can be welded to the housing at an angle to the channel axis, and the ultrasonic probe can be aligned with the mounting bracket, i.e., positioned longitudinally within the mounting bracket. Such an arrangement is disclosed, for example, in CN 212082488 U1. However, due to the angled mounting bracket, this is associated with the risk of an uneven weld seam and undesirable distortion, which in many cases necessitates extensive rework.

[0005] Nozzles angled to the channel axis can also be produced by forming or casting. However, this also involves considerable manufacturing effort. In high-pressure applications, the wall thickness of the housing is typically so great that forming techniques are not feasible anyway.

[0006] To avoid misalignment of the mounting nozzle with the canal axis, a bent ultrasound probe could also be used; that is, an ultrasound probe with a bend so that the radiation direction is oblique to the probe axis. However, such probes are relatively expensive. Furthermore, positioning them with the required accuracy is difficult.

[0007] CN 2 658 719 Y discloses a flow measurement system comprising an ultrasonic probe and a valve inserted between the probe and the duct housing. A section of pipe connected to the valve is attached to the duct housing by means of a mounting component.

[0008] US Patent 5,396,814 A discloses a flow meter comprising two ultrasonic units, each attached to the associated pipe by means of a respective bracket. The brackets are welded to the pipe.

[0009] CN 212 082 485 U discloses a flow measurement system with two ultrasonic probes arranged in respective receptacles of a mounting component.

[0010] It is an object of the invention to provide a flow measurement system of the aforementioned type which ensures an exact and stable positioning of the ultrasonic probe using simple means and preferably without mechanical post-processing.

[0011] The problem is solved by a flow measurement system with the features of claim 1.

[0012] According to the invention, the mounting stub has a cylindrical surface that surrounds a stub axis running perpendicular to the channel axis and extends from a housing-side end region of the mounting stub in the direction of the stub axis, wherein a circumferential weld seam is formed in the transition area between the cylindrical surface of the mounting stub and the outer wall of the housing.

[0013] Thus, at least the part of the mounting sleeve facing the housing can be aligned perpendicular to the channel axis, which facilitates the welding process and, in particular, enables a comparatively uniform weld geometry, especially a uniform weld gap and a consistent weld seam, in contrast to a mounting sleeve welded at an angle to the housing. Distortion of the mounting sleeve during cooling is minimized. It has been found that, in a flow measurement system according to the invention, particularly precise positioning of the ultrasonic probe is ensured even when the mounting sleeve is welded to the housing automatically and without post-processing.

[0014] If the housing has a round cross-section, the transition area between the outer surface of the mounting fitting and the outer wall of the housing is curved, so that the path of the circumferential weld seam exhibits an axial variation with respect to the fitting axis. This axial variation decreases as the diameter of the housing increases and the diameter of the outer surface of the mounting fitting decreases. In many applications, the fluid line is so large compared to the mounting fitting that the curvature of the transition area is practically negligible and has virtually no impact on the weld. To achieve a weld seam without any axial variation, the curved housing wall in the welding area can optionally be provided with a flat section. This further improves the welding process and results in a mounting fitting with a geometry that is easy to manufacture.The flat surface section can be cut out into the housing material in the area of ​​the mounting stud, or alternatively, it can be applied to the housing material as a base in the area of ​​the mounting stud.

[0015] The housing of the flow measurement system can be designed as a component to be inserted into the fluid line or can itself form a section of the fluid line.

[0016] One embodiment of the invention provides that the outer surface has a cylindrical shape and defines a cylinder axis that runs parallel to the nozzle axis and preferably coincides with it. Such a mounting nozzle, at least partially cylindrical in shape, is particularly easy to manufacture.

[0017] The mounting nozzle can have at least one contact surface for the ultrasound probe extending obliquely to the nozzle axis, in particular a flat surface, in order to ensure an oblique alignment of the ultrasound probe despite the right-angled alignment of the mounting nozzle.

[0018] Preferably, the mounting stud has a flat clamping tool engagement surface that extends perpendicular to the stud axis. This allows the mounting stud to be clamped against the housing at a right angle during the welding process using simple means such as clamps. A flat clamping tool engagement surface is particularly advantageous in the case of two opposing mounting studs, as the parallel engagement surfaces can then be clamped towards each other.

[0019] The ultrasound probe can have a longitudinal axis coinciding with the direction of radiation and one extending perpendicular to the longitudinal axis.

[0020] They have a signal transmission area. In contrast to an angled ultrasound probe, a straight-radiating ultrasound probe is inexpensive and easy to position.

[0021] According to the invention, at least one spacer projects from the outer wall of the housing and abuts a boundary surface of the mounting stud. Such a spacer ensures that a defined weld gap exists for the welding process. Furthermore, a spacer enables particularly high clamping forces. The at least one spacer can be bolt-shaped and inserted into a bolt receptacle in the housing. Preferably, at least two spacers project from the outer wall of the housing and abut a boundary surface or respective boundary surfaces of the mounting stud. In particular, exactly two spacers can be provided, which are preferably arranged opposite each other with respect to a passage hole for ultrasonic signals from the ultrasonic probe.

[0022] At least one positioning pin can project from the outer wall of the housing, which is received in a pin receptacle of the mounting sleeve. This ensures simple and precise positioning of the mounting sleeve relative to the housing. Preferably, at least two positioning pins project from the outer wall of the housing, which are received in respective pin receptacles of the mounting sleeve. In particular, exactly two positioning pins can be provided, which are preferably arranged opposite each other with respect to a passage hole for ultrasound signals from the ultrasound probe.

[0023] Preferably, the housing has at least one through-hole for ultrasound signals from the ultrasound probe, aligned with the mounting surface. Spacers and positioning pins, as described above, can be arranged around the through-hole.

[0024] The flow measurement system can include at least one additional ultrasonic probe that can be attached to the housing, with a measuring path running obliquely to the channel axis between the two ultrasonic probes attached to the housing. Depending on the application, two or more pairs of ultrasonic probes can also be provided to form a corresponding number of measuring paths. In principle, it is also possible for a reflection measuring path to be established by two ultrasonic probes and a reflector.

[0025] The housing may be at least partially tubular and preferably fitted with screw flanges at both ends. The axis of the tubular section may coincide with the channel axis. Such a housing can easily be designed to withstand high pressure and thus be installed in a high-pressure pipeline.

[0026] The invention also relates to a method for attaching an ultrasound probe having a direction of radiation to a housing having a fluid channel and defining a channel axis by the course of the fluid channel.

[0027] An inventive method comprises the following steps: Providing a mounting nozzle that has a receptacle for the ultrasound probe and a lateral surface that surrounds a nozzle axis and extends from an end region of the mounting nozzle in the direction of the nozzle axis, positioning the mounting nozzle relative to the housing such that there is an air gap between the end region and the outer wall of the housing and the nozzle axis is perpendicular to the channel axis, welding the mounting nozzle to the outer wall of the housing by forming a circumferential weld seam in the area of ​​the air gap, and inserting the ultrasound probe into the receptacle of the mounting nozzle such that the direction of radiation of the ultrasound probe is oblique to the nozzle axis.

[0028] The mounting bracket is therefore welded to the housing at a right angle, not at an angle. The oblique orientation of the ultrasonic signals relative to the channel axis is not caused by an oblique orientation of the mounting bracket, but by an oblique orientation of the ultrasonic probe relative to the mounting bracket. Since the outer surface adjacent to the air gap has a uniform orientation to the housing wall, the weld geometry is consistent, thus minimizing distortion during cooling. The positioning of the mounting bracket, and therefore of the ultrasonic probe, is so precise that costly post-weld machining can potentially be avoided.

[0029] According to the invention, the mounting stud is brought into position against the housing until at least one spacer arranged on the outer wall of the housing abuts an end face of the mounting stud. This ensures a defined weld gap and enables reliable through-welding. Particularly when multiple mounting studs are present, it is advantageous to equip the housing with corresponding spacers before bringing the mounting studs into position. However, it is also possible to bring the mounting stud into position against the housing until at least one spacer arranged on an end face of the mounting stud abuts the outer wall of the housing.

[0030] The spacer may be bolt-shaped and inserted into a bolt receptacle in the housing. This bolt receptacle may be a through hole in the outer wall of the housing.

[0031] The mounting bracket can be positioned so that at least one positioning pin located on the outer wall of the housing engages in a pin recess of the mounting bracket. This ensures precise positioning of the mounting bracket. Particularly when multiple mounting brackets are present, it is advantageous to equip the housing with positioning pins before the mounting brackets are brought into position. However, it is also possible to position the mounting bracket by bringing it into contact with the housing until at least one positioning pin on the mounting bracket engages in a pin recess of the housing.

[0032] The positioning pin can be inserted into a pin recess in the housing. The pin recess can be a through hole in the outer wall of the housing.

[0033] One embodiment of the invention provides that the mounting sleeve is clamped against the housing during welding by means of a clamping tool, in particular wherein the clamping tool is brought into contact with a clamping tool contact surface of the mounting sleeve, which preferably extends perpendicular to the sleeve axis. This allows, in particular, welding distortion to be minimized.

[0034] One embodiment of the invention provides that, prior to positioning the mounting sleeve, at least one passage hole for ultrasound signals is formed in the housing, and the mounting sleeve is positioned such that the passage hole is aligned with the receptacle for the ultrasound probe. Depending on the application, the ultrasound probe can protrude into the passage hole or even protrude through it.

[0035] In the case of a housing with a curved outer wall, the outer wall can be provided with at least one flat surface section before the mounting fitting is positioned, for example by cutting a recess into the housing material or by applying a base to the housing material. However, as described above, the fluid line is often so large compared to the mounting fitting that any curvature of the transition area between the outer surface of the mounting fitting and the outer wall of the housing is practically negligible and does not affect the welding even without such an additional measure.

[0036] Further developments of the invention can also be found in the dependent claims, the description and the accompanying drawings.

[0037] The invention is described below by way of example with reference to the drawings. Fig. 1 shows a flow measurement system according to the invention in a side sectional view. Fig. 2 is an enlarged partial view of the [unclear text]. Fig. 1 The flow measurement system shown. Fig. 3 shows a housing of the system shown in Fig. 1 The flow measurement system shown is shown before the insertion of positioning pins and spacers. Fig. 4 shows the housing according to... Fig. 3 with inserted positioning pins and spacers. Fig. 5 shows one attached to the housing according to Fig. 4 . attached mounting studs. Fig. 6 shows the housing according to Fig. 4 . with several welded-on mounting studs.

[0038] The in Fig. 1 The flow measurement system 11 shown, designed according to an embodiment of the invention, comprises a metal housing 13, preferably a single piece, which has a fluid channel 15. As shown, the fluid channel 15 is straight and defines a channel axis 17. In the illustrated embodiment, the housing 13 is tubular, with the fluid channel 15 having a circular cross-section. For installation in a fluid piping system (not shown), the housing 13 can be provided with end-face screw flanges, which in Fig. 1 however, it is not shown.

[0039] Two ultrasonic probes 21, 22 are attached to the housing, between which a measuring path 25 extending obliquely to the channel axis 17 is formed. This means that the emission directions 27 or signal directions of the ultrasonic probes 21, 22 are not parallel or perpendicular to the channel axis 17, but at an oblique angle 28. Passage holes 31 are provided for the ultrasonic signals to pass through the wall 29 of the housing 13. The ultrasonic probes 21, 22 are connected to an electronic control and evaluation unit (not shown) of the flow measurement system 11.

[0040] The ultrasound probes 21, 22 are located in respective mounting sockets 33, which are welded to the outside of the wall 29 of the housing 13. One of the two identical mounting sockets 33 with its associated ultrasound probe 21 is in Fig. 2 The image is shown enlarged. The ultrasound probe 21 is partially cylindrical and has a longitudinal axis 39 that coincides with the direction of radiation 27. The signal transmission surface 41 of the ultrasound probe 21 extends perpendicular to the longitudinal axis 39, meaning that the ultrasound probe 21 is not angled.

[0041] A central recess 35 of the mounting sleeve 33, aligned with the passage hole 31, forms a receptacle 36 for the ultrasound probe 21, wherein a flat surface is inclined to the channel axis 17 ( Fig. 1 ) extending mounting surface 37 for the ultrasound probe 21 ensures that the longitudinal axis 39 of the ultrasound probe 21 runs obliquely to the channel axis 17 when the ultrasound probe 21 is in the receptacle 36.

[0042] The mounting fitting 33 has a cylindrical outer surface 43, which defines a fitting axis 45 of the mounting fitting 33. The cylindrical outer surface 43 extends around the fitting axis 45 and reaches to the wall 29 of the housing 13. The fitting axis 45 is perpendicular to the channel axis 17, meaning that the mounting fitting 33 is welded to the housing 13 at a right angle. The corresponding weld 46 at the transition between the cylindrical outer surface 43 and the wall 29 of the housing 13 runs completely around the housing.

[0043] Since the cylindrical surface 43 of the mounting sleeve 33 abuts the housing 13 at a right angle rather than at an angle, the distortion of the welded assembly is minimized. The alignment of the ultrasonic probe 21 is sufficiently accurate even when the welding process is automated and no mechanical post-processing is required.

[0044] The mounting sleeve 33 has a flat clamping tool engagement surface 47 at one end facing away from the housing 13, which extends perpendicular to the sleeve axis 45 and thus parallel to the channel axis 17 when the mounting sleeve 33 is welded to the housing 13. This allows the mounting sleeve 33 to be clamped against the housing 13 in a favorable manner during the welding process.

[0045] The following refers to the Fig. 3-5 a method according to the invention for producing the in Fig. 1 The flow measurement system shown in section 11 is described.

[0046] First, a tubular housing 13 is provided. The wall 29 of the housing 13 is then constructed as described in Fig. 3 Several passage openings 31 for ultrasound signals are shown, as well as non-through-holes 51 distributed around the passage openings 31. Positioning pins 53 and spacer bolts 55 are inserted into the receiving holes 51 ( Fig. 4 ), preferably clamping. As shown, two positioning pins 53 and two spacer bolts 55 are arranged opposite each other with respect to a passage opening 31.

[0047] Then, for each of the through-openings 31, a mounting stud 33 designed as described above is provided and aligned so that the stud axis 45 extends perpendicularly to the channel axis 17 of the housing 13. Each mounting stud 33 is brought against the housing 13 such that the positioning pins 53 are positioned as shown in Fig. 5 The mounting stud 33 is brought into contact with the housing 13 via pin receptacles 57. The positioning of the mounting stud 33 continues until the spacer bolts 55 abut a flat end face 58 of the mounting stud 33 and a uniform air gap 61 is formed between the wall 29 of the housing 13 and the mounting stud 33.

[0048] By means of a clamping tool (not shown) that acts on the clamping tool's engagement surface 47 in an axial direction with respect to the nozzle axis 45, the mounting nozzle 33 is clamped against the housing 13 and thus fixed. The clamping tool does not need to perform a positioning function, as this function is performed by the positioning pins 53. The mounting nozzle 33 is then welded to the wall 29 of the housing 13 by means of a welding device (not shown), whereby the weld seam 46 ( Fig. 2 ) forms.

[0049] The ultrasound probes 21, 22 are then inserted into the receptacles 36 of the mounting sockets 33. As a result, the emission direction 27 of each ultrasound probe 21, 22 is oblique to the channel axis 17. This oblique orientation of the ultrasound signals is not caused by an oblique orientation of the mounting socket 33 relative to the housing 13, but by an oblique orientation of the ultrasound probe 21 relative to the mounting socket 33.

[0050] Fixing the mounting studs 33 to the housing 13 is simplified in particular by the fact that, as in Fig. 6 It is evident for each pair of fastening studs 33 that there are clamping tool engagement surfaces 47 running parallel to each other and opposite to the channel axis 17, which can be acted upon in opposite directions.

[0051] For positioning the mounting studs 33, milled recesses could also be provided on the housing 13. Furthermore, two or more receptacles 36 with ultrasonic probes 21, 22 could be provided in a single mounting stud 33. The length of the mounting studs 33 can be adapted to the thickness of the wall 29.

[0052] A flow measurement system 11 according to the invention can be designed to withstand high pressure without difficulty due to its favorable welding geometry. Precise positioning of all ultrasonic probes 21, 22 is ensured even if no mechanical post-processing is carried out after welding. Bezugszeichenliste

[0053] 11 Flow measurement system 13 Housing 15 Fluid channel 17 Channel axis 21 Ultrasonic probe 22 Ultrasonic probe 25 Measuring path 27 Radiation direction 28 Oblique angle 29 Wall 31 Through hole 33 Mounting spigot 35 Recess 36 Receptacle 37 Contact surface 39 Longitudinal axis 41 Signal transmission surface 43 Cylindrical outer surface 45 Spigot axis 46 Weld seam 47 Clamping tool engagement surface 51 Mounting bore 53 Positioning pin 55 Spacer bolt 57 Pin receptacle 58 End face 61 Air gap

Claims

1. A throughflow measurement system (11) for measuring a fluid throughflow in a fluid line, in particular in a high pressure line, said throughflow measurement system (11) comprising: a housing (13) which has a fluid channel (15) and which defines a channel axis (17) by means of the course of the fluid channel (15), at least one ultrasonic probe (21, 22) which can be fastened to the housing (13) and which has a radiation direction (27), wherein, for fastening the ultrasonic probe (21, 22) to the housing (13), a fastening stub (33) is provided that is welded to the outer wall (29) of the housing (13) and that has a receiver (36) for the ultrasonic probe (21, 22), wherein the radiation direction (27) of the ultrasonic probe (21, 22) extends obliquely to the channel axis (17) when the ultrasonic probe (21, 22) is arranged in the receiver (36), wherein the fastening stub (33) has a lateral surface (43) which revolves around a stub axis (45) extending at a right angle to the channel axis (17) and which extends, starting from a housing-side end region of the fastening stub (33), in the direction of the stub axis (45), wherein a peripheral weld seam (46) is formed in the transition region between the lateral surface (43) of the fastening stub (33) and the outer wall (29) of the housing (13), characterized in that at least one spacer (55) projects from the outer wall (29) of the housing (31) and contacts a boundary surface (58) of the fastening stub (33).

2. A throughflow measurement system according to claim 1, wherein the lateral surface (43) has a circular cylindrical shape and defines a cylinder axis which extends in parallel with the stub axis (45) and preferably coincides therewith.

3. A throughflow measurement system according to claim 1 or 2, wherein the fastening stub (33) has at least one contact surface (37), in particular a planar contact surface (37), for the ultrasonic probe (21, 22), said contact surface extending obliquely to the stub axis (45).

4. A throughflow measurement system according to any one of the preceding claims, wherein the fastening stub (33) has a planar clamping tool engagement surface (47) which extends at a right angle to the stub axis (45).

5. A throughflow measurement system according to any one of the preceding claims, wherein the ultrasonic probe (21, 22) has a longitudinal axis (39) coinciding with the radiation direction (27) and a signal transmission surface (41) extending at a right angle to the longitudinal axis (39).

6. A throughflow measurement system according to any one of the preceding claims, wherein at least one positioning pin (53) projects from the outer wall (29) of the housing (13) and is received in a pin receiver (57) of the fastening stub (33).

7. A throughflow measurement system according to any one of the preceding claims, wherein at least one passage hole (31), which is in alignment with the receiver (36), for ultrasonic signals of the ultrasonic probe (21, 22) is formed in the housing (13).

8. A throughflow measurement system according to any one of the preceding claims, wherein the throughflow measurement system (11) has at least one further ultrasonic probe (21, 22) which can be fastened to the housing (13), wherein a measurement path (25) extending obliquely to the channel axis (17) is formed between the two ultrasonic probes (21, 22) fastened to the housing (13).

9. A throughflow measurement system according to any one of the preceding claims, wherein the housing (13) is at least sectionally tubular and is preferably provided with screw flanges at both ends.

10. A method for fastening an ultrasonic probe (21, 22), which has a radiation direction (27), to a housing (13) which has a fluid channel (15) and which defines a channel axis (17) by means of the course of the fluid channel (15), comprising the steps: providing a fastening stub (33) which has a receiver (36) for the ultrasonic probe (21, 22) and a lateral surface (43) which revolves around a stub axis (45) and which extends, starting from an end region of the fastening stub (33), in the direction of the stub axis (45), positioning the fastening stub (33) relative to the housing (13) such that there is an air gap (61) between the end region and the outer wall (29) of the housing (13) and the stub axis (45) extends at a right angle to the channel axis (17), welding the fastening stub (33) to the outer wall (29) of the housing (13) while forming a peripheral weld seam (46) in the region of the air gap (61), and inserting the ultrasonic probe (21, 22) into the receiver (36) of the fastening stub (33) such that the radiation direction (27) of the ultrasonic probe (21, 22) extends obliquely to the stub axis (45), characterized in that the fastening stub (33) is moved towards the housing (13) during the positioning until at least one spacer (55) arranged at the outer wall (29) of the housing (13) abuts an end face (58) of the fastening stub (33).

11. A method according to claim 10, wherein the spacer (55) is bolt-shaped and is inserted into a bolt receiver (51) of the housing (31).

12. A method according to one of the claims 10 or 11, wherein the fastening stub (33) is moved towards the housing (13) during the positioning such that at least one positioning pin (53) arranged at the outer wall (29) of the housing (13) enters into a pin receiver (57) of the fastening stub (33), wherein the positioning pin (53) is preferably inserted into a pin receiver (51) of the housing (13).

13. A method according to any one of the claims 10 to 12, wherein the fastening stub (33) is clamped against the housing (13) by means of a clamping tool during the welding, in particular wherein the clamping tool is brought into contact with a clamping tool engagement surface (47) of the fastening stub (33), said clamping tool engagement surface (47) preferably extending at a right angle to the stub axis (45).

14. A method according to any one of the claims 10 to 13, wherein at least one passage hole (31) for ultrasonic signals is formed in the housing (13) before the positioning of the fastening stub (33) and the fastening stub (33) is positioned such that the passage hole (31) is aligned with the receiver (36) for the ultrasonic probe (21, 22).