MEASURING DEVICE AND METHOD FOR ITS MANUFACTURING

Description

[0001] The invention relates to a measuring device for measuring the flow rate of a medium flowing in a measuring tube using ultrasound, the measuring tube being arranged in a housing of the measuring device between an inlet and an outlet for the medium. The invention also relates to a manufacturing method for such a measuring device.

[0002] The measurement of flow rates using well-transmittable measuring sections is already known for free-flowing media and is used in various concepts. The design of measuring sections within housings is familiar, and these designs can vary depending on factors such as available space and the application.

[0003] From EP 0 681 162 A1, a measuring device for measuring fluid flows using ultrasound is known. It comprises a housing with connection heads for the inflow and outflow of the liquid, which open into distribution chambers and are arranged essentially coaxially to one another. A measuring tube connects the distribution chambers. Ultrasonic transducers are arranged in the housing near the ends of the measuring tube, which is inclined relative to the connecting axis of the connection heads. The device is constructed from many parts; its sensors are in contact with the medium, the measuring tube is an insert, and it contains many constantly changing cross-sections and dead spaces.

[0004] German patent DE 10 2005 041 288 A1 and US patent 2007 / 062305 A1 disclose a flow meter for measuring the flow velocity of media flowing in a pipeline. The device comprises a measuring tube with ultrasonic transducers at each end and connecting tubes for inserting the flow meter into and axially to the pipeline. Due to the axiality of the connections, the flow direction changes several times before the measuring section. Furthermore, the manufacturing process is complex due to the large number of valves. A connecting tube, which branches off at a 90° angle from the measuring tube and connects the measuring tube and the connecting tube, alters the flow path. This connecting tube must also be sealed with a plug, which can create capillaries / dead spaces between the connecting tube wall and the plug. Sealing the tube also requires an additional work step.

[0005] DE 10 2008 019 989 A1 shows a measuring device in which a measuring tube is subsequently encased in a housing.

[0006] German patent DE 10 2010 033 858 A1 discloses a housing for an ultrasonic fluid flow measuring device, comprising a fluid inlet, a fluid outlet, a measuring section with a measuring path, and at least two coupling areas, in particular coupling surfaces, for an ultrasonic transducer. The housing comprises two separately manufactured housing parts connected and / or connectable in the measuring path, with the housing part containing the fluid inlet and the housing part containing the fluid outlet each comprising at least one coupling area. Due to the different housing parts, the device is complex and also includes a separate measuring tube and seals. Furthermore, the device operates by reflecting sound, with the reflectors projecting into the measuring channel. This creates turbulence that can negatively affect the measurement result, and the flow of the medium is impeded by pressure losses.

[0007] From DE 10 2014 010 375 A1, an ultrasonic transducer arrangement with a pocket-shaped housing for mounting the ultrasonic transducer arrangement in a through-hole in the housing of an ultrasonic water meter in a mounting plane is known, wherein an ultrasonic measuring section is located in the housing of the ultrasonic water meter, along which a transit-time measurement can be carried out using the ultrasonic transducer arrangement. Here, the measuring section with a large diameter is traversed obliquely by ultrasound, and the respective transducers are arranged externally in the measuring tube via a seal, which poses a risk of leakage.

[0008] US Patent 5,717,145A describes a flow meter that is free from external flow noise. The detector has a measuring tube, an inlet, and an outlet, both aligned axially to the base axis. The tube is a straight tube with opposing, upstream and downstream closed ends, each equipped with an echo sounder capable of transmitting and receiving ultrasound.

[0009] DE 10 2019 009 033 A1 discloses a component for installation in a fluid line, comprising a measuring section for a fluid flow meter and a housing. The housing has an inlet and an outlet for the fluid. Furthermore, the housing forms a substantially straight flow path between the inlet and outlet. The measuring section is arranged transversely or at an angle to this substantially straight flow path. This arrangement also necessitates sealing the pockets for the transducers, in front of which an accumulation of air not carried along by the flow is likely.

[0010] It is therefore the object of the present invention to provide a measuring device that is easy and inexpensive to manufacture with high reliability, and whose small number of individual parts can be assembled with reduced assembly effort.

[0011] This problem is solved by a device with the features of claim 1. The solution according to the invention therefore consists in particular in that, in the measuring device, the measuring tube is arranged in a housing of the measuring device between an inlet and an outlet for the medium, wherein at least two ultrasonic transducers spaced apart from one another along the measuring tube are provided for transmitting sound through the medium, wherein at least one ultrasonic transducer is arranged in each end region of the measuring tube such that a measuring section is formed between the ultrasonic transducers, which allows transmission parallel to a longitudinal axis of the measuring tube, wherein a receptacle is provided in each end region of the measuring tube on the housing in which at least the respective ultrasonic transducer can be received or is received, wherein the respective receptacle is separated from the measuring tube by a wall section of the respective housing part.and wherein the wall section has a substantially constant wall thickness over the majority of the cross-sectional area of ​​the measuring tube, wherein the housing, together with the measuring tube, can be assembled or is assembled from at least one housing part made of plastic and manufactured by means of a forming process, wherein the housing is formed with two identical housing parts which can be joined or are joined together without seals by a welding process. According to the invention, the measuring device is characterized in that channel sections arranged at the inlet and outlet are curved in the form of a circular arc and are each formed by means of a single curved slide, the outer wall of which forms the wall section facing the respective ultrasonic transducer, and that a center point of the circle to which the circular arc is assigned,The measuring device according to the invention has an eccentric offset relative to the longitudinal axis of the measuring tube. It therefore comprises an injection-molded measuring tube in which the sound transmission advantageously occurs parallel (and antiparallel) to the flow of the medium. The sound path is reflection-free, capillary-free, and free of dead spaces. Furthermore, the measuring section has a virtually unchanged diameter along its entire length, which significantly reduces the corrections required when determining the measured quantity(ies).

[0012] Moreover, the arrangement of the channel sections according to the invention promotes reliable and uniform coupling of the ultrasound into the measuring section, since the center of the circle associated with the circular arc is offset from the longitudinal axis of the measuring tube in such a way that a radius of the circle runs parallel, but not coaxially, to the longitudinal axis of the measuring tube. This offset is located in the direction of the respective channel section.

[0013] Preferred embodiments of the device according to the invention can be found in the corresponding dependent claims.

[0014] In an advantageous embodiment of the device according to the invention, the measuring tube can have a round, in particular circular, cross-section, thereby creating a suitably well-permeable measuring section. In particular, the measuring section is advantageously designed essentially along its entire length without any change in cross-section.

[0015] In an embodiment of the measuring device according to the invention that can be very well integrated into a pipeline through which the respective medium flows, the channel sections are each provided with a connecting piece at their end facing away from the measuring tube, the connecting pieces having a common central axis that forms a tangent to the circular arc. In this way, the inlet and outlet of the measuring device are aligned with each other.

[0016] In a preferred embodiment, which ensures good accessibility of the sensors, these are located on opposite end faces of the housing, i.e., in an end region of the respective housing section. While the respective wall section must be penetrated by the transducer, contact with the medium is prevented. The wall section preferably covers the entire cross-section of the measuring tube. The wall thickness is not necessarily uniform at every point of the wall section, but it is uniform to such an extent that a consistent wall thickness can be assumed to cover the vast majority of the measuring tube's cross-section.

[0017] In order to protect the ultrasonic transducers from their environment and to reduce any unintended negative influences on the measurement process, in a further embodiment the respective receptacle can be provided to be closable by means of a cover part, so that the interior of the receptacle is isolated from the environment of the measuring device.

[0018] To ensure that access to the transducer(s) or any additional sensors within the housing, or indeed to its interior, is still possible if necessary, a preferred embodiment allows the cover to be detachably connected to the respective housing part. The connection between the cover and the housing can be configured in various ways. For example, a threaded engagement can be provided between the cover and the housing, at least one of the connecting parts can be pre-tensioned relative to the other by its shape, or a snap-fit ​​and / or detent connection can be provided. This list is not exhaustive. A sealant can also be provided between the cover and the housing.

[0019] The arrangement and fixing of the transducers in the respective receptacles is sensibly carried out such that each transducer is held in a fixed position on the wall section of the receptacle that covers the cross-section of the measuring section. In a further embodiment, a plunger can be assigned to the cover part for this purpose, which, in the operating position, presses at least the respective ultrasonic transducer against the wall section. The plunger can also press other sensors, e.g., a temperature sensor, against the wall section. The plunger can preferably be designed to be compliant or elastic to a certain extent, and it is also preferably designed to be rotatable relative to the respective cover part. Optionally or additionally, other fixings can be provided; for example, the transducers / sensors can be encapsulated in the receptacle. The plunger can also be formed integrally with the cover part.

[0020] In a preferred embodiment of the measuring device according to the invention, an elastic element can also be arranged between the punch and the respective ultrasonic transducer, so that a defined but gentle transmission of the contact force to the ultrasonic transducer is achieved. The elastic element can be in the form of a piece of foam, for example, but other embodiments are also conceivable.

[0021] In the case of fixation by means of a plunger, in a preferred embodiment this plunger is designed to be movable relative to the cover part, so that forces from movement of the cover part are not transmitted to the transducer or its cable with negative consequences. If the cover part is screwed to the receptacle by means of a thread, it is advantageous to provide the plunger preferably to be rotatable relative to the cover part. However, the plunger is preferably designed to be rotationally fixed relative to the measuring tube, and thus relative to the transducer and any other sensors.

[0022] In another advantageous embodiment of the ultrasonic measuring device, the housing components along the measuring tube can include a closable compartment formed by joining the housing components. This compartment is designed to house electronic components. Connectors for joining the transducer cables to connecting cables, as well as measuring electronics, such as evaluation electronics or adapter boards between the aforementioned cables, can be accommodated within this compartment. At least one non-volatile memory component can also be located there, capable of storing and retaining calibration values. The compartment can be sealed, for example, by a lid or by a casting process.

[0023] In another embodiment, a fastening device can be provided at an opening edge of the installation space to fix the measuring device in a specific installation location. This fastening device secures the respective housing part to which it is attached and, consequently, the entire housing. It can, for example, be an eyelet or a slot located in a section projecting from the housing part, through which a fastening element engages when the device is secured.

[0024] In order to conveniently feed connecting cables to the measuring device and secure them to the housing, a further embodiment of the measuring device according to the invention allows the housing parts to have a closable opening in one of the housing wall sections. The connecting cable can be fed through this opening and screwed in place with a nut. When not in use, the opening can be closed by various means, such as fitting a cover, potting, or the like.

[0025] The above-mentioned problem is also solved by a method for manufacturing a measuring device for measuring the flow rate of a medium flowing in a measuring tube using ultrasound, in particular a measuring device according to one of the preceding claims, comprising at least the following steps: Providing an injection mold for a housing part; inserting a straight slide and a slide describing a circular arc segment into the injection mold, wherein the center point of the circle associated with the circular arc has an eccentric offset relative to the longitudinal axis of the straight slide; closing the mold and injection molding the housing part, wherein the curved slide forms a channel section of the housing part with a wall section opposite an ultrasonic transducer of the measuring device; demolding the housing part and removing the slides; joining two housing parts in a seal-free welding process along a seam; arranging ultrasonic transducers in receptacles of the housing parts.

[0026] In the inventive method, the arrangement of the channel sections also promotes reliable and uniform coupling of the ultrasound into the measuring section, since the center of the circle associated with the circular arc is offset from the longitudinal axis of the measuring tube such that a radius of the circle runs parallel, but not coaxially, to the longitudinal axis of the measuring tube. This offset is located in the direction of the access opening to the measuring tube and is achieved by the arrangement of the slides designed with the appropriate geometry.

[0027] The above embodiments and further developments can be combined with one another as appropriate. Further possible embodiments, further developments, and implementations of the invention also include combinations of features of the invention described previously or subsequently with regard to the exemplary embodiments, as defined by the appended patent claims, which are not explicitly mentioned.

[0028] The invention is explained in more detail below with reference to exemplary embodiments shown in the figures of the drawing. These figures are shown in a partially schematic representation: Fig. 1 a flat, cutaway side view of a first embodiment of a measuring device with a housing composed of two housing parts; Fig. 2 an enlarged view of an end area of ​​the measuring device from the Fig. 1 ; Fig. 3 a perspective side view of a housing part of the measuring device from the Fig. 1 und 2 on the end face facing the other (not shown) part of the housing; Fig. 4 an enlarged section of the illustration of the measuring device from the Fig. 2 without depicting the circular arc. Fig. 5 a flat, cutaway side view of a second embodiment of the measuring device, in which the receptacle of the housing part, in which an ultrasonic transducer and a temperature sensor are arranged, is closed by another cover part, and in which the transducer and the temperature sensor are encapsulated in the receptacle; Fig. 6 a perspective side view of one of the measuring devices from the Fig. 1 bis 4 , with fastening devices arranged on the housing parts and measuring electronics housed in a space next to the measuring tube; Fig. 7 a plan view from above of a measuring device from the Fig. 6 ; Fig. 8a-8c Each a perspective side view of a housing part of the measuring device from the Fig. 1 bis 3 as well as 6 and 7 during demolding by removing the slides from the injection-molded housing part.

[0029] The accompanying figures are intended to provide a further understanding of the embodiments of the invention. They illustrate embodiments and, in conjunction with the description, serve to explain the principles and concepts of the invention. Other embodiments and many of the advantages mentioned become apparent with regard to the drawings. The elements of the drawings are not necessarily shown to scale.

[0030] In all figures, identical or functionally equivalent elements and devices have been provided with the same reference numerals, unless otherwise stated.

[0031] The Fig. 1 Figure 1 shows a planar, sectioned side view of a first embodiment of the measuring device 10 with a housing 30 composed of two housing parts 30a, 30b. The measuring device 10 shown is designed for measuring the flow rate of a medium flowing into the measuring tube 20 using ultrasound. The measuring tube 20 in the housing 30 extends between the inlet 21 and the outlet 22, which supply and discharge the medium flowing in the measuring tube, respectively. Ultrasonic transducers 40a, 40b, positioned at opposite ends of the measuring tube 20, are provided for transmitting ultrasound signals through the medium. An ultrasonic transducer 40a, 40b is arranged at each end of the measuring tube 20 such that a measuring section is formed between the transducers 40a, 40b, which allows transmission parallel to a longitudinal axis 23 of the measuring tube 20.The housing 30, together with the measuring tube 20, is composed of two housing parts 30a and 30b, the housing parts 30a and 30b being manufactured from a plastic using an injection molding process. The housing 30 is formed with two identical housing parts 30a and 30b, which are joined together without a seal by a welding process. How this can be further improved... Fig. 2 Where fluid is extracted, channel sections 12a, 12b arranged at the inlet 21 and outlet 22 of the housing 30 are curved in the form of a circular arc, wherein the center point of the circle to which the circular arc belongs has an eccentric offset 25 relative to the longitudinal axis 23 of the measuring tube 20. The center point 27 of the circle associated with the circular arc is offset relative to the longitudinal axis 23 of the measuring tube 20 such that a radius 28 of the circle runs parallel, but not coaxially, to the longitudinal axis 23 of the measuring tube.

[0032] The Fig. 2 shows an enlarged view of an end area of ​​the measuring device from the Fig. 1 . This can be seen both in Fig. 1 as in Fig. 2 , that in the end regions of the measuring tube 20, a receptacle 32a, 32b is provided on the housing 30, in which the respective ultrasonic transducer 40a, 40b is accommodated. The receptacles 32a, 32b are located on the opposite end faces of the housing 30. Each receptacle contains an ultrasonic transducer 40a, 40b, and receptacle 32a of the housing part 30a additionally accommodates a temperature sensor 42. The receptacles 32a, 32b are closed by a cup-shaped cover 50, which overlaps the outer wall of each receptacle. A recess on the edge of the cover 50 forms a bayonet fitting with a projection on the outer wall of the receptacle 32a, 32b. Since this can be reopened by means of a rotary movement, the cover part 50 presses the ultrasonic transducer 40a, 40b and the temperature sensor 42 against the side of the wall section 34a, 34b facing away from the measuring tube 20 via a separate plunger 52. The plunger 52 is flexible to a certain extent.It is designed to be elastic and is rotatable relative to the respective cover part 50, but rotationally fixed relative to the respective receptacle 32a, 32b or the housing part 30, 30b. Furthermore, the flexibility is achieved here by an elastic element 54 arranged between the punch piece 52 and the ultrasonic transducer 40a.

[0033] The respective inlet 32a, 32b is separated from the measuring tube 20 by the wall section 34a, 34b of the respective housing part 30a, 30b. The wall section 34a, 34b has a constant wall thickness over the majority of the cross-sectional area of ​​the measuring tube 20. This is particularly evident from the Fig. 2 The fact that channel sections 12a, 12b of the housing 30, arranged at the inlet 21 and outlet 22, are curved in the form of a circular arc, and that the center point of the circle to which the arc is assigned has an eccentric offset 25 relative to the longitudinal axis of the measuring tube 20. This means that the wall section 34a of the housing part 30a is approximately straight for a distance transverse to the longitudinal axis 23 of the measuring tube 20 that is longer by the offset 25, allowing the sound to be coupled into the measuring section particularly effectively parallel / antiparallel to the flow direction of the medium. Furthermore, it can be seen that the channel sections 12a, 12b are each provided with a connecting piece 14 at their end facing away from the measuring tube 20, the connecting pieces 14 having a common central axis 26 that forms a tangent to the circular arc. The central axis 26, the longitudinal axis 23 of the measuring tube 20 and the circle radius 28 are in the Fig. 2 Shown with dashed lines.

[0034] The Fig. 3 shows a perspective side view of a housing part 30a of the measuring device from the Fig. 1 und 2 on the end face facing the other, not shown, housing part 30b. It can be seen in particular that the measuring tube 20 has a circular cross-section. Furthermore, it can be seen that a closable installation space 35 is formed on the housing 30 or the assembled housing parts 30a, 30b, next to the measuring tube 20 by joining the housing parts 30a, 30b to form the housing 30. The installation space 35 is offset from the plane in which the cross-section of the measuring tube 20 and channel sections 12a, 12b is located.

[0035] In the Fig. 4 is an enlarged section of the illustration of the measuring device 10 from the Fig. 2 The circular arc is shown without illustration, as it has been omitted for the sake of clarity, particularly regarding the recording area. The arrangement of the ultrasonic transducer 40a on the side of the wall section 34a facing away from the measuring tube 20, and its pressure against this side by the interaction of the cover part 50, the plunger piece 52, and the elastic element 54, are particularly evident here. Further details can be seen from the Fig.4 It is particularly good that a sealing agent in the form of a gasket 57 is arranged between the cover part 50 and the edge of the receiving area 32a.

[0036] The Fig. 5 Figure 1 shows a planar, sectioned side view of a second embodiment of the measuring device 10, in which the receptacle 32a of the housing part 30a, in which an ultrasonic transducer 40a and a temperature sensor 42 are arranged, is closed by another cover part 51. Furthermore, in this embodiment, Fig. 5 The ultrasonic transducer and the temperature sensor are encapsulated in the housing. Fig. 5 The cover part 51 itself, with its end facing the interior of the receptacle 32a, forms a kind of plunger that presses the ultrasonic transducer 40a and the temperature sensor 42 against the wall piece. The cover part 51 thereby engages with the inner edge of the receptacle 32a in a snap-fit ​​connection.

[0037] The Fig. 6 shows a perspective side view of one of the measuring devices 10 from the Fig. 1 bis 4 , with fastening devices 37 arranged on the housing parts 30a, 30b and measuring electronics 55 accommodated in a construction space 35 next to the measuring tube 20. The Fig. 7 shows a plan view from above of a measuring device 10 from the Fig. 6 It can be clearly seen that the installation space 35 next to the measuring tube 20 is created by joining the housing parts 30a, 30b to form the housing. Furthermore, it can be seen that an eyelet-like fastening device 37 is provided at the opening edge 36 of the installation space 35, by means of which the respective associated housing part 30a, 30b, and thus of course also the housing 30 itself, can be secured. It is also shown that the housing parts 30a, 30b have a closable opening 39 in a housing part wall 38, through which a connection socket 56 is guided and secured at the opening 39, whereby the measuring device can be connected to a signal path by means of a plug.

[0038] The Fig. 8a-8c Each shows a perspective side view of a housing part 30a of the measuring device 10 from the Fig. 1 bis 3 as well as 6 and 7 during demolding by removing slides 62, 64 from the injection-molded housing part 30a. The slides 62, 64, a straight slide 62 and a circularly curved slide 64, had previously been inserted into an injection mold (not shown) in a process step of the manufacturing process according to the invention. In the sectional perspective view of the Fig. 8a The slides 62, 64 can be seen in their position as assumed during the injection molding process, while in the cutaway perspective view of the Fig. 8b are already partially pulled out of the recess they create in the housing part 30a. In the uncut perspective side view of the Fig. 8c The slides 62 and 64 are completely removed from the cast housing part 30a, with the straight slide 62 forming a section of the measuring tube of the measuring device 10, and the curved slide 64 forming the arc-shaped channel section 12a. It can also be seen that the slides 62 and 64 have angled end sections which, when placed in the injection mold in the casting position, form a positive-locking engagement with each other such that overhang-free cross-sections are created on the measuring tube 20 and the channel sections.

[0039] After the removal of the slides 62, 64 as described, two housing parts 30a, 30b produced in this way can now be joined to form a housing by means of a welding process and the ultrasonic transducers can be placed in the receptacles 32a, 32b (in Fig. 8a-8c (not shown).

[0040] Although the present invention has been described above with reference to preferred embodiments, it is not limited thereto, but can be modified in a variety of ways. In particular, the invention can be altered or modified in many ways without deviating from the core of the invention, which is defined by the appended claims. Reference symbol list

[0041] 10 Measuring device 12a, 12b Channel sections 14 Connection piece 20 Measuring tube 21 Inlet 22 Outlet 23 Longitudinal axis of the measuring tube 25 Offset 26 Center axis of connection piece 27 Center of circle 28 Circle radius 30 Housing 30a, 30b Housing part 32a, 32b Receptacle 34a, 34b Wall section 35 Installation space 36 Opening edge of the installation space 37 Mounting device 38 Housing part wall 39 Opening 40a, 40b Ultrasonic transducer 42 Temperature sensor 50 Cover part 51 Cover part 52 Stamp piece 54 Elastic element 55 Measuring electronics 56 Connection socket 57 Seal 60 Seam 62 Straight slide 64 Curved slide

Claims

1. Measuring device (10) for measuring the flow of a medium flowing in a measuring tube (20) by means of ultrasound, which measuring tube (20) is arranged in a housing (30) of the measuring device (10) between an inlet (21) and an outlet (22) for the medium, wherein at least two ultrasonic transducers (40a, 40b) spaced apart from one another along the measuring tube (20) are provided for transmitting sound through the medium, wherein at least one ultrasonic transducer (40a, 40b) is respectively arranged in the end regions of the measuring tube (20) in such a way that a measurement section is formed between the ultrasonic transducers (40a, 40b), which permits sound transmission parallel to a longitudinal axis (23) of the measuring tube (20), wherein a receptacle (32a, 32b) is respectively provided in the end regions of the measuring tube (20) on the housing (30), in which at least the respective ultrasonic transducer (40a, 40b) can be or is accommodated, wherein the respective receptacle (32a, 32b) is separated from the measuring tube (20) by a wall section (34a, 34b) of the respective housing part (30a, 30b), and wherein the wall section (34a, 34b) has a substantially uniform wall thickness over the majority of the cross-sectional area of the measuring tube (20), wherein the housing (30) together with the measuring tube (20) can be assembled or is assembled from housing parts (30a, 30b) made of at least one plastic and manufactured by means of a primary forming manufacturing method, wherein the housing (30) is formed with two identical housing parts (30a, 30b), which can be or are connected to one another without a seal by a welding process, characterised in that channel sections (12a, 12b) arranged at the inlet (21) and outlet (22) are curved in the shape of an arc and respectively shaped by means of a single curved slider (64), whose outer wall shapes the wall section (34a, 34b) facing the respective ultrasonic transducer (40a, 40b), and in that a centre point (27) of the circle which is associated with the arc has an eccentric offset (25) relative to the longitudinal axis (23) of the measuring tube (20).

2. Measuring device according to claim 1, wherein the measuring tube has a round, in particular circular, cross-section.

3. Measuring device according to claim 1 or 2, wherein the channel sections (12a, 12b) are respectively provided with a connecting piece (14) at their end facing away from the measuring tube (20), wherein the connecting pieces (14) have a common central axis (26), which forms a tangent of the arc.

4. Measuring device according to one of the preceding claims, wherein the receptacles (32a, 32b) are respectively located at the end faces of the housing (30) facing away from one another.

5. Measuring device according to one of the preceding claims, wherein the respective receptacle (32a, 32b) can be closed by means of a cover part (50).

6. Measuring device according to claim 5, wherein the cover part (50) is provided so as to be releasably connectable to the respective housing part (30a, 30b).

7. Measuring device according to claim 5 or 6, wherein the cover part (50) is associated with a punching part (52), which presses the respective ultrasonic transducer (40a, 40b) at least indirectly against the wall section (34a, 34b) in the use position.

8. Measuring device according to claim 7, wherein an elastic element (54) is arranged between the punching part (42) and the respective ultrasonic transducer (40a, 40b).

9. Measuring device according to claim 7 or 8, wherein the punching part (52) is provided to be moveable, in particular rotatable, with respect to the cover part (50) and secured against rotation preferably with respect to the respective housing part (30a, 30b).

10. Measuring device according to one of the preceding claims, wherein the housing parts (30a, 30b) have, along the measuring tube (20) adjacent thereto, a closeable installation space (35) formed by assembling housing parts (30a, 30b) to form the housing, which space is designed to accommodate electronic components.

11. Measuring device according to claim 10, wherein a fastening device (37) is provided on an opening edge (36) of the installation space (35), by means of which the respective housing part (30a, 30b) can be fixed.

12. Measuring device according to one of the preceding claims, wherein the housing parts (30a, 30b) have a closeable opening (39) in a housing part wall (38).

13. Method for producing a measuring device (10) for measuring the flow of a medium flowing in a measuring tube (20) by means of ultrasound, in particular a measuring device (10) according to one of the preceding claims, having at least the following steps: - providing an injection mould for a housing part (30a, 30b); - inserting a straight slider (62) and a slider (64) defining a circular arc section into the injection mould, wherein a centre point of the circle associated with the arc has an eccentric offset relative to the longitudinal axis of the straight slider (62); - closing the mould and injection moulding the housing part (30a, 30b), wherein a channel section (12a, 12b) of the housing part (30a, 30b) is formed by the curved slider (64) with a wall section (34a, 34b) opposite an ultrasonic transducer (40a, 40b) of the measuring device (10); - demoulding the housing part (30a, 30b) and removing the sliders (62, 64); - connecting two housing parts (30a, 30b) in a seal-free manner in a welding process along a seam (60); - arranging ultrasonic transducers (40a, 40b) in receptacles (32a, 32b) of the housing parts (30a, 30b) .