flow meter

Abstract

A flow meter having an optimized throughflow cross section is disclosed.

Description

TECHNICAL FIELD

[0001] The present application relates to a flow meter for measuring the flow rate of a fluid in a pipe or the like. BACKGROUND

[0002] The flow meter can for example have two ultrasonic transducers which are inserted spaced apart from one another on a pipe piece of the pipe as a so-called "clamp-on solution", wherein both transducers function as transmitter and receiver. The measuring signal is coupled into the fluid obliquely through the pipe piece wall.

[0003] The flow rate can then be determined from the propagation time of the measuring signal from the transmitter to the receiver in a manner known per se. Such a flow meter is described for example in the documents WO 2004 / 036151 A1 and DE 10 2005 057 888.

[0004] A disadvantage of clamp-on flow meters is that the measuring signal passes through the wall of the measuring channel, so that in the case of different materials with which the measuring channel can be configured, also different measuring signals are obtained, so that the material influence has to be taken into account in the evaluation of the measuring signal.

[0005] Furthermore, solutions are known which have a measuring insert in which the ultrasonic transducers are accommodated. Such a measuring insert is inserted into a recess of the pipe piece / measuring channel, wherein the actual measuring channel can also be part of the measuring insert.

[0006] Such a solution is disclosed for example in DE 101 20 355 A1, wherein two ultrasonic transducers are arranged spaced apart from one another in the flow direction and on opposite sides of the measuring channel.

[0007] In EP 2 306 160 A1 a flow meter / flow counter is disclosed, wherein the measuring insert not only accommodates the ultrasonic transducers but also configures the actual measuring channel. The measuring insert is fastened on a tangentially extending flange of a pipe piece of the housing of the flow meter. Here, a profile body which configures the measuring channel is embedded in a recess through the pipe piece which is surrounded by the flange, the profile body influences the flow in the measuring region and on the profile body an additional reflector for the measuring signal is provided. In this solution, two ultrasonic transducers are arranged in a pot-shaped housing part of the measuring insert, which housing part is closed towards the flow and is embedded in the flow.

[0008] A similar solution is shown in EP 2 386 836 B1. In this embodiment, the measuring insert carries two ultrasonic transducers arranged offset to one another in the flow direction, which are likewise accommodated in a pot-shaped housing part and project into the measuring channel through the flange-encircled opening of the tube of the housing. The flow guidance inside the measuring channel is determined by a housing insert that can be fitted from the end side of the housing, which also carries a reflector for the ultrasonic signals, so that the ultrasonic waves are output by one of the ultrasonic transducers and reflected by the reflector to the other, for example downstream, ultrasonic transducer. Of course, the signal guidance can also take place in the reverse direction.

[0009] In the document EP 0 890 826 B1, a flowmeter is described in which the measuring insert is attached to a tangentially extending flange also in the region of the tube of the housing. The measuring insert carries two ultrasonic transducers, which are inserted into recesses in the bottom of the housing part and are sealed there by means of a seal each. The entire measuring insert is then sealed relative to the flange with a further, surrounding seal, which surrounds the two ultrasonic transducers. The measuring channel is also configured in this embodiment by the measuring insert, which is inserted into the tube of the housing through a recess encircled by the flange. Similar solutions are described in US 8,424,392 B2 and EP 3 748 311 A1.

[0010] The document DE 199 44 411 A1 discloses a flowmeter in which an insert is configured in the measuring tube, by means of which the cross section of the measuring tube is configured elongatedly. Here, two ultrasonic transducers are arranged offset in the flow direction on opposite sides of the measuring channel.

[0011] In EP 0 650 034 A1, a flowmeter is described in which likewise two ultrasonic transducers are arranged offset to one another. Reflectors are arranged on the bevels of the measuring channel respectively opposite one another.

[0012] In all the above-described solutions, the reflectors are configured diametrically to the ultrasonic transducers, so that at least two reflectors must be provided in order to guide the ultrasonic signals.

[0013] In the flowmeter according to EP 0 890 826 B1, the two ultrasonic transducers are arranged in a sensor housing, which is referred to as coupling piece hereinafter, respectively and project into the measuring channel in the radial direction, so that they are surrounded by the flow.

[0014] Flowmeters are disclosed in US 2013 / 167 655 A1 and DE 10 2004 061 404 A1, respectively, in which two ultrasonic sensors are arranged in a measurement housing which is fitted onto a measurement channel, the measurement housing being open towards the measurement channel, so that in the transition region to the measurement housing vortices can occur.

[0015] The disadvantage of this solution is that either the ultrasonic transducers are arranged with their coupling pieces directly in the flow or else a housing piece, for example a pot, which surrounds the ultrasonic transducers, projects into the flow. Separation and / or vortices can occur on the ultrasonic transducers or housing pieces which project into the flow or spring back into the flow, which lead to measurement errors, in particular depending on the flow rate.

[0016] Flowmeters in which measurement inserts are pushed into the measurement channel in the axial direction have the disadvantage that these measurement inserts are very limited in terms of geometry, since the prerequisite for the axial push-in is that the measurement insert and the measurement channel are configured without lateral recesses. Furthermore, tapering in the inlet region and outlet region can only be realized with difficulty or at most with a considerable wall thickness of the measurement insert.

[0017] EP 2 696 174 A1 discloses a flowmeter with two ultrasonic sensors which are attached on a measurement channel, wherein the coupling-in and coupling-out of the measurement signals into / from the fluid is realized by coupling pieces which are flush inserted into the peripheral wall of the measurement channel.

[0018] A flowmeter is described in WO 2018 / 011 371 A1 from the applicant, in which the coupling-in and coupling-out of the measurement signals of two measurement sensors which are spaced apart from one another is carried out by a common or respectively one coupling piece, which carries the sensor / transducer or respectively the sensors / transducers.

[0019] In the parallel patent application WO 2018 / 011 372 A1 a flowmeter is described which has an elliptical or trapezoidal measurement channel.

[0020] The two flowmeter solutions ensure an improved throughflow of the flowmeter with improved measurement accuracy relative to the prior art described above.

[0021] A flowmeter with a flow-optimized measurement channel is described in the document WO 2016 / 012024 A1, however the flowmeter has a very complex structure.

[0022] The document WO 2011 / 127934 A1 discloses a flowmeter, wherein the ultrasonic sensors are accommodated in a housing, which itself is connected with the measuring channel by means of a locking mechanism. This flowmeter has a very complex structure, since the reflectors for diverting the measuring beams are also configured on the housing and thus embedded in the net cross section of the measuring channel in radial direction and thus adversely affect the flow.

[0023] In EP 2 888 560 A1 a flowmeter is described, wherein two ultrasonic sensors are likewise arranged in a closed housing, which is embedded in the measuring channel through a radial recess. These embedded areas again interfere with the throughflow of the measuring channel. Furthermore, the area of the housing, which is embedded inside the measuring channel, is used for fixing a measuring insert, which is inserted in the measuring channel in axial direction. The measuring insert carries the reflectors for deflecting the measuring beams. Similar to the above-described solution, the measuring channel and the measuring insert have to be coordinated with each other, realizing the insertion of the axial end side of the measuring insert.

[0024] The European patent application EP 3 818 343 A1 relates to a structure of a housing, which has a control part accommodated therein. The control part has a main PCB, which has a CPU and a communication circuit accommodated in a module housing, which in turn is accommodated in the housing, in which also a measuring PCB is arranged. The two PCBs are connected with each other via a power and communication connection, wherein in the housing also a current supply of the components is accommodated.

[0025] This housing structure is extremely complex and thus requires significant device-technical expenditure.

[0026] The European patent EP 2 414 789 B1 relates to a flowmeter, wherein the ultrasonic sensors are arranged directly on a PCB. The prerequisite of this solution is that the PCB and thus also the sensors are positioned very close to the flow channel in order to ensure sufficient signal quality, so that little freedom remains in the design. The same applies to the solution according to EP 3 550 272 B1, wherein the ultrasonic sensors are arranged on the underside of a PCB.

[0027] In EP 2 888 561 B1 an ultrasonic flowmeter is described, wherein the electrical contacting of the ultrasonic sensors is realized by means of elastic connectors, which are mechanically connected with an insulating carrier device. This solution also requires a huge device-technical expenditure. Furthermore, the disclosure of EP 2 888 561 B1 corresponds to the disclosure of the aforementioned European patent application EP 2 888 560 B1.

[0028] The European patent EP 1 544 582 B1 relates to a flowmeter, wherein a measuring insert is likewise inserted into the measuring channel in axial direction. It is furthermore presupposed that the cross section of the measuring channel is configured hexagonal, octagonal or essentially square with rounded corners. This measuring insert can also only be realized with considerable device-technical outlay and a corresponding design of the measuring channel cross section. SUMMARY

[0029] In contrast thereto, the task of the present application is to improve the flowmeter with optimum measuring accuracy in terms of further reduction of device-technical outlay.

[0030] This task is solved by a flowmeter according to the application.

[0031] According to a first aspect of the application, the flowmeter has a flow channel which can be attached on a pipe through which a fluid flows, on which flow channel a measuring unit is held, which has at least two sensors, preferably ultrasonic transducers, which are spaced apart from one another, the measuring signals of which are coupled in and out through at least one aperture of the flow channel. Furthermore, the flowmeter has a control unit which is accommodated in a control housing for actuating the sensors and for processing the measuring signals. The measuring channel is embodied as a multipart measuring channel insert having at least one measuring channel upper part and one measuring channel lower part. Here, the fluid inlet and / or the fluid outlet are respectively configured as inserts and are inserted into the flow channel through the aperture.

[0032] This solution has the advantage over the prior art mentioned at the outset that in fact the entire measuring channel insert can be inserted in radial direction through the at least one aperture of the flow channel. The total length of the measuring channel insert with the two inlet / outlet inserts and the measuring channel upper part and the measuring channel lower part is configured here to be longer than the clear width of the aperture.

[0033] This solution enables, for example, that the measuring channel insert is adapted to different nominal widths of the flowmeter by simply exchanging the inserts forming the outlet and the inlet and, if necessary, exchanging the measuring channel lower part.

[0034] The device-technical outlay is particularly simple when the two inserts are embodied identically in structure.

[0035] In a particularly preferred embodiment of the application, the inlet and outlet inserts are configured with an axial stop towards the measuring channel upper part or towards the measuring channel lower part, by which the axial position of the inserts within the flow channel is defined.

[0036] The inserts are preferably embodied such that they have a circular opening cross section on the one hand and a rectangular opening cross section on the other hand.

[0037] The installation is carried out here in such a way that firstly the two inlet and outlet inserts are inserted into the flow channel through the gap of the flow channel and then moved out of the push-in region in the axial direction until the axial stop comes onto the respective shoulder of the flow channel and thus cannot be moved further. In the next installation step, the measuring channel lower part and the measuring channel upper part are then inserted through the gap in the radial direction and the inserts are thus also positionally fixed. These two inserts and the measuring channel lower part and the measuring channel upper part then complement one another to form the measuring channel insert, the axial length of which is greater than the clear width of the gap. This solution makes it possible to virtually realize any measuring channel geometry and here reduces the gap at the flow channel to a minimum.

[0038] According to a further aspect of the application, the throughflow cross section of the two inserts and of the measuring channel lower part and the measuring channel upper part is designed in such a way that in the transition region from the inserts to the measuring channel section configured by the measuring channel upper part and the measuring channel lower part a reduction in the throughflow cross section is provided, so that the fluid is accelerated in this region. Surprisingly, it has been shown that by this acceleration of the fluid flow and the subsequent enlargement of the cross section in the measuring channel section the measurement error can be reduced.

[0039] If guide ribs are provided in the region of the inlet and outlet inserts in the measuring channel, the flow can be further homogenized.

[0040] In a particularly preferred embodiment, the measuring channel upper part has a housing flange on which a control housing accommodating control electronics and a current supply is attached. Here, the housing flange also configures the bottom of the control housing, so that the control housing can be manufactured at low cost.

[0041] In an alternative solution, the measuring channel upper part and the measuring channel lower part are attached to the bottom of the control housing, so that the bottom of the control housing, the measuring channel upper part and the measuring channel lower part define the measuring channel section on the circumference side.

[0042] If the measuring channel upper part, the measuring channel lower part and the control housing are positioned relative to one another form-fittingly, in particular by means of a mating piece / mating gap, the relative positioning of the components is particularly simple.

[0043] If the measuring channel section has a substantially rectangular cross section, the throughflow properties can be further optimized, wherein it is preferred that the height of the measuring channel, for example in the direction towards the control housing, is significantly greater than the height transverse to the control housing.

[0044] When the length of the measuring channel section is less than 40 mm in the case of a nominal width of 110 mm or 80 mm, the flowmeter is particularly compactly configured.

[0045] If at least one reflector is held in place on the lower measuring channel and / or the upper measuring channel, for example by injection molding, preferably in a form-fitting manner, the expenditure in terms of device technology is further reduced. Here, for example, two reflectors can be provided on the upper measuring channel and one reflector on the lower measuring channel, so that a roughly W-shaped signal path is set.

[0046] The fastening of the ultrasonic sensors is particularly simple when these are fastened on an obliquely disposed support surface on the upper measuring channel or on the bottom of the control housing.

[0047] This fastening is preferably achieved in a form-fitting manner by gluing or in a force- fitting manner by tensioning.

[0048] Of course, the fastening can also be carried out by soldering or the like.

[0049] The contact of the sensors with the main PCB is achieved by means of a cable or by means of a plastic molding provided with a contact strip.

[0050] The contact according to a further aspect of the application is particularly simple when each sensor is in contact with a contact plate, which itself is connected to the PCB by means of a cable or a plastic molding. The contact plate can here also be part of the plastic molding.

[0051] The fastening of the sensors is particularly simple when the contact plate is soldered or glued to the sensor, wherein the sensor electrode is configured in a region remote from the large-area region of the control housing or of the upper measuring channel bottom, in other words remote from the support of the sensor, and / or along the peripheral wall of the sensor. In this solution, no contact is provided in the support region of the sensor, so that a positional fastening can be achieved without taking the actual contact into account.

[0052] The relative positioning between the contact plate and the sensor is particularly simple when the contact plate is positioned with respect to the control housing or the upper measuring channel in a form-fitting manner, in particular via a reference recess and a reference pin that is inserted therein.

[0053] In an embodiment of the application, the control housing has a housing cover that is configured with a display cover, so that the display arranged in the control housing can be seen through the cover.

[0054] This housing cover and the positional fastening of the control housing are particularly simple when a multipart mobile frame is used.

[0055] The installation of the flowmeter can be further simplified when the upper measuring channel, the lower measuring channel and optionally the control housing are connected to the flow channel by means of a screw connection or a snap-fit connection.

[0056] The attachment of the flowmeter on the pipe is particularly simple when the control housing is conical towards the connecting pipe of the flow channel, so that the attachment of the tool is not impeded by the control housing.

[0057] In a particularly preferred embodiment, the measuring channel insert and optionally also the flow channel are made of plastic.

[0058] In a preferred embodiment of the application, the battery is arranged on a large area of the main PCB facing the measuring channel insert, so that the upper side of the PCB remote from this large area can be occupied by a display or a transmission unit.

[0059] Depending on the type of battery (C cell or D cell) and the nominal width of the flowmeter, the battery can be arranged in the control housing with its longitudinal axis transversely or parallel to the throughflow direction.

[0060] As mentioned above, the display unit and the communication module can be accommodated in the control housing, wherein these are arranged offset with respect to the main PCB at a parallel distance relative to the housing cover.

[0061] In a further very compact solution, the communication unit is embodied with an antenna integrated into the control housing, which is covered by the housing cover. In this way, damage to the antenna is reliably prevented.

[0062] Further independent aspects of the application will be set out below.

[0063] The measuring channel is preferably embodied with a substantially rectangular, rounded-off in the corner region, cross section. However, alternatively, other cross sections can also be used, for example an oval or ovoid cross section. An elongated cross section with rounded-off narrow sides and parallel side walls (stadium) or other cross sections which are optimized not only in terms of manufacturing technology but also in terms of fluid dynamics can also be realized.

[0064] The cross section in the fluid inlet and the fluid outlet is preferably substantially circular or ovoid in design, so that the profile can be manufactured in a simple manner. This cross section then continuously transitions in the transition region into the above-described cross section of the measuring channel.

[0065] The sensor is preferably arranged such that the signal is coupled in or out obliquely, i.e. at an angle to the longitudinal axis of the measuring channel.

[0066] In a particularly preferred embodiment of the application, three reflectors are provided which are arranged alternately between the sensors, so that an approximately W-shaped signal path is produced. In a solution, the sensors and the reflectors are arranged such that an approximately V-shaped signal path is set.

[0067] These reflectors can be rounded in accordance with the profile of the measuring channel and flushly inserted into the measuring channel wall, so that the flow is further optimized.

[0068] For optimizing the guiding of the measuring channel, the coupling-in or coupling-out surface of the sensor or the reflector surface of the reflector can be rounded concavely, so that the signal path is focused in the direction of the next component, for example the opposing reflector or sensor.

[0069] The reflector can be arranged in a region between two sensors, wherein the measuring channel has a slightly smaller flow cross section in this region than in the region adjacent to the fluid inlet or fluid outlet.

[0070] The sensors and the respectively assigned reflectors are preferably each configured in a conically tapering section of the above-mentioned transition region, the throughflow cross section of which increases towards the measuring channel. In order to further homogenize the flow, the throughflow cross section of the measuring channel can be tapered again after the above-mentioned conically tapering section.

[0071] In an embodiment of the application, the center distance between two sensors is between 30 and 60 mm.

[0072] In an embodiment of the flowmeter, the sensors are bonded or tensioned with a measuring channel insert which configures the measuring channel, whereby the expenditure in terms of device technology is reduced in relation to conventional solutions.

[0073] In an embodiment, the material of the measuring channel insert is optimized in terms of flow guiding and the material of the flow channel which is external is optimized in terms of protection of the flowmeter against external influences. This is achieved, for example, in that the flow channel and the measuring channel insert are composed of different materials. In a preferred embodiment of the application, the single-piece or multi-piece measuring channel insert is composed of plastic and the flow channel which is external is composed of a metal material.

[0074] In an alternative solution, a part of the measuring channel insert and the flow channel can be configured substantially integrally by means of a multi-component injection molding method or other injection molding methods.

[0075] Instead of the commercially common contact of the sensors by means of cables / wires, in one embodiment, the contact can be realized by means of a form body or spring body which is inserted into the flowmeter structure, as explained. Such springs can also be implemented as SMD spring contacts, for example, so that these spring contacts assume a kind of dual function of contact with the sensor and position fixation or at least contribute to the position fixation. The fastening of the form body or spring body can be realized by means of bonding or welding. BRIEF DESCRIPTION OF DRAWINGS

[0076] In the following, preferred embodiments of the application are explained in more detail by means of the schematic drawings. Shown are:

[0077] Figure 1is a three-dimensional view of a first embodiment of a flowmeter according to the present application;

[0078] Figure 2 is Figure 1 is an exploded view of the flowmeter in

[0079] Figure 3 is a detail view of a measuring channel insert of the flowmeter according to Figure 1 and Figure 2

[0080] Figure 4 is a diagram for illustrating the installation of a sensor in the measuring channel insert according to Figure 3

[0081] Figure 5 is a schematic view of the installation of the measuring channel insert in the flow channel according to Figure 3 and Figure 4

[0082] Figures 6 to 13 is a schematic view of a possible cross section of the measuring channel of the flowmeter according to the present application;

[0083] Figure 14 is an embodiment of the flowmeter, wherein the flow channel is made of plastic;

[0084] Figure 15 is an exploded view of a further embodiment of the flowmeter according to the present application;

[0085] Figure 16 is a variant of the embodiment according to Figure 15

[0086] Figure 17 is an embodiment of the flowmeter according to Figure 16 wherein the structure of the control unit is shown;

[0087] Figure 18 is the flowmeter according to Figure 17 with a control housing in a kit;

[0088] Figure 19 is the flowmeter according to Figure 17 and Figure 18 with means for identifying the flowmeter;

[0089] Figure 20 is a schematic view of a further embodiment of the flowmeter according to the present application with different nominal widths;

[0090] Figure 21 is a sequence for the installation of a sensor for contacting the further embodiment of the flowmeter;

[0091] Figure 22 ​​​​is an alternative embodiment, in which the shaped body is used for the contact sensor;

[0092] Figure 23 is a variant of the flow meter, in which the control unit is fixed in position at the upper part of the housing by the support pin;

[0093] Figure 24 is a greatly simplified manufacturing step for manufacturing a flow meter with flow channels made of plastic;

[0094] Figure 25 is a cross section of the flow meter for illustrating the position fixing of the control housing relative to the control channel;

[0095] Figure 26 is an alternative possibility for fixing the sensor position within the upper part of the measuring channel or within the control housing;

[0096] Figure 27 is a three-dimensional illustration of a further embodiment of the flow meter;

[0097] Figure 28 is an exploded view of the flow meter according to Figure 27 ;

[0098] Figure 29 is a cross-sectional view of the flow meter according to Figure 27 and Figure 28 ;

[0099] Figure 30 , 31 is a detail view of the sensor housing of the flow meter according to Figure 29 ;

[0100] Figure 32 , 33 is a detail view of the upper part of the measuring channel of the flow meter according to Figure 29 ;

[0101] Figure 34 is a detail view of the lower part of the measuring channel of the flow meter according to Figure 29 ;

[0102] Figure 35 , 36 is a detail view of the insert of the flow meter according to Figure 29 ;

[0103] Figure 37 is a corresponding illustration with installed sensor of Figure 30 ;

[0104] Figure 38 , 39 is a detail of the contact of the sensor in the flow meter according to the invention;

[0105] Figure 40 is a schematic of two flow meters with different nominal widths and a coned housing;

[0106] Figure 41 is a mounting possibility of different batteries in a flow meter according to the invention;

[0107] Figure 42 is a mounting of a display side construction assembly in a flow meter according to the invention;

[0108] Figure 43 is a mounting step for fixing the measuring housing on the flow channel;

[0109] Figure 44 , 45 , 46 is a schematic of a possibility for positioning an antenna of a communication module;

[0110] Figure 47 is a view of a further embodiment of a flow meter according to the invention, and

[0111] Figure 48 , 49 is an embodiment of a flow meter with a flow channel made of plastic.

[0112] Wherein: 1 - flow meter; 2 - measurement housing; 4 - inlet insert; 6 - outlet insert; 8 - control housing; 10 - flow channel; 12 - connecting tube; 14 - connecting tube; 16 - recess; 18 - flange; 20 - measurement channel insert; 22 - sensor; 24 - sensor; 26 - sensor holder; 28 - housing flange; 30 - control unit; 32 - control housing; 34 - housing cover; 36 - carrier structure; 38 - drying means; 40 - display; 42 - measurement channel section; 44 - measurement channel upper part; 46 - measurement channel lower part; 48 - information plate; 52 - reflector; 54 - line; 56 - line; 58 - measurement channel; 59 - recess; 60 - recess; 61 - recess; 62 - recess; 64 - signal path; 66 - guide rib; 68 - profile; 70 - profile; 72 - main PCB; 74 - EDU; 78 - battery; 80 - connecting bolt; 82 - SMD spring contact; 86 - reference pin; 88 - reference recess; 90 - circuit trace; 92 - circuit trace; 94 - base; 96 - contact arm; 98 - housing seal; 100 - support pin; 102 - pin cutout; 103 - mating bolt; 104 - cover; 106 - display window; 108 - communication module; 109 - guide; 110 - cover flange; 112 - cover glass; 114 - moving frame; 116 - seal; 118 - seal; 120 - bottom; 124 - contact board; 126 - contact board; 128 - support; 130 - receiving cavity; 132 - measurement channel adapter; 134 - mating recess; 136 - in-coupling surface; 138 - out-coupling surface; 140 - step; 142 - sidewall; 144 - sidewall; 146 - bracket; 148 - mating recess; 149 - bottom surface; 150 - wall; 152 - wall; 153 - through opening; 154 - mating pin; 156 - mating protrusion; 160 - recess; 162 - mating pin; 164 - slot; 166 - tube; 168 - profile; 170 - contact; 172 - electrode; 174 - electrode; 176 - board arm; 178 - board arm; 180 - mating recess; 182 - mating recess; 184 - board arm; 186 - board arm; 188 - mating recess; 190 - wall surface; 191 - antenna; 192 - wall surface; 193 - antenna winding; 194 = communication board; 196 - antenna receptacle; 198 - top cover; 200 - mating element; 200 - recess. DETAILED DESCRIPTION

[0113] Figure 1 A three-dimensional view of an embodiment of a flow meter 1 according to the present application is shown, having a flow channel 10 configured measurement housing, a fluid inlet and a fluid outlet configured thereon and a control housing 8 attached thereto, which houses a control unit of the flow meter 1. Thereby, the flow meter 1 is characterized by a very compact construction, wherein the number of installed components is minimized.

[0114] The flow meter 1 according to the present application, which will be explained in more detail below, is characterized by a very good transmission factor (ps / l) (this factor indicates the increase in flow in liters (l) in the time difference T (ps)); a high transmission factor means that for the measurement a higher reproducibility is obtained than in the case of lower values, so that at low flow rates it is possible to reduce or at least compensate signal noise (signal jitter). This is determined by the predetermined sensor distance and the appropriate flow rate in the flow meter 1.

[0115] In addition, the flow meter is designed in such a way that the pressure loss when flowing through is minimized. This is achieved, inter alia., in that the measurement channel described below is embodied with continuous transitions. In addition, the measurement channel is configured in such a way that no recesses, undercuts or other obstacles are configured which could accumulate gas bubbles.

[0116] The flow meter 1 described below with an optimized measurement channel in terms of signal detection and fluid dynamics is characterized by an optimal signal quality with sufficient signal strength without signal noise and without interference.

[0117] In addition, standard ultrasonic sensors (transducers) can be used, so that the manufacturing price is minimized. The manufacture of the flow meter 1 can here take place according to standard manufacturing methods.

[0118] Figure 2 An exploded view of the flow meter 1 is shown, in which, in the following embodiments, inter alia., the measurement channel insert 20 and the measurement channel configured thereby are discussed. As shown, the flow meter can be embodied for pipes with a nominal width of DN 15, DN 20, DN 25 or DN 32, of course, the flow meter can also be provided in other dimensions.

[0119] According to the following Figures 1 to 24 First, several basic components of different embodiments of the flow meter 1 according to the present application are explained. Further details are then derived from the following more detailed description of further embodiments.

[0120] As can be gathered from the exploded view according to Figure 2 The flow meter 1 has a flow channel 10 (also referred to as housing), which in the shown embodiment is made of brass or a metal alloy.

[0121] The flow channel 10 has connecting pipes 12, 14 by means of which the flow meter 1 can be connected to a pipe through which a fluid is conducted. As will be explained in more detail below, the flow channel 10 has a radial recess 16 which opens into a flange 18 on which a control housing 32 can be attached, the structure of which will be explained in more detail below. A measuring channel insert 20 can be inserted through the radial recess 16. In the embodiment shown, this measuring channel insert carries two ultrasonic sensors 22, 24 which are fastened in a suitable manner on the measuring channel insert 20. In the embodiment shown, the fastening is effected, for example, by means of sensor holders 26. An actual control unit 30 for the actuation, signal supply and current supply of the sensors 22, 24 is arranged on a housing flange 28 of the multipart measuring channel insert 20. This control unit 30 is accommodated in a control housing 32 which is closed or covered upwards (view according to Figure 2 ) by means of a housing cover 34. The control unit 30 is held by a carrier structure 36 on which a drying device 38 is also supported.

[0122] As can be gathered from Figure 1 and Figure 2 , a display 40 arranged on the control unit 30 can be read through the cover 34, which will be discussed in more detail below.

[0123] As is shown in the lower left side of Figure 2 , the flow channel 10 or the housing constructed therefrom can be provided with different nominal widths, wherein the actual control unit 30 with the control housing 32 and the sensors 22, 24 is designed independently of the nominal width. For adaptation, only the measuring channel insert 20 needs to be modified.

[0124] According to the detail view in Figure 3 , the measuring channel insert 20 is constructed with a measuring channel section 42 which consists of a measuring channel upper part 44 and a measuring channel lower part 46. An inlet insert 4 and an outlet insert 6 are provided on the inlet side and on the outlet side, which are implemented in each case according to the nominal width of the pipe. The measuring channel upper part 44 is also implemented with a housing flange 28 to which / into which the control housing 8 and the sensors 22, 24 are attached / inserted.

[0125] In the embodiment shown, three reflectors 52a, 52b, 52c are inserted into the peripheral wall portion of the measuring channel insert 20, thereby constructing a W-shaped signal path 64.

[0126] The individual parts of the measuring channel insert 20 can be constructed, for example, from fiber-reinforced plastic or other plastic materials. Of course, they can also be made of metal materials.

[0127] Figure 4 is shown according toFigure 3 The measuring channel insert 20 is in a partially mounted state, wherein also two sensors 22, 24 are shown, which are fastened in the housing flange 28 by means of a sensor holder 26, wherein the signal lines 54, 56 of the sensors 22, 24 are guided through the sensor holder 26 to a not shown control housing 32.

[0128] In Figure 4 A cross section of the partially mounted measuring channel insert 20 is shown in the lower right. It can be seen that the sensor holder 26 is screwed and tensioned with the measuring channel upper part 44, wherein in the measuring channel upper part 44 notches / recesses 59, 61 are configured into which the sensors 22, 24 are embedded with their coupling faces. Opposite each of the sensors 22, 24 one of the reflectors 52a, 52b is configured. A third reflector 52c is between the two sensors 22, 24, so that as explained a W-shaped signal path 64 is set. In principle also a double sensor can be used, so that two signal paths can be realized. A V-shaped signal path is also conceivable. The profile of the measuring channel defined by the measuring channel insert 20 will also be discussed in more detail below.

[0129] According to Figure 5 The multi-part measuring channel insert 20, which is preferably made of plastic, is inserted into the flow channel 10, which is configured as a stable housing. This stable housing can be made of a metal casting, for example. Here, first the inserts 4, 6, which configure the fluid inlet and the fluid outlet, are inserted into the notches 16 of the flange 18 and then the actual measuring channel section with the measuring channel upper part 44 and the measuring channel lower part 46 is inserted in the radial direction, so that the housing flange 28 of the measuring channel insert 20 lies on the flange 18 of the flow channel 10.

[0130] The connecting pipes 12, 14 of the flow channel 10 are designed with threads or other connection elements in the shown embodiment, so that the flowmeter 1 can be attached to the pipes in a simple manner.

[0131] Figure 6 A view of the measuring channel design configured by the above-mentioned components is shown. The measuring channel 58 is embodied without flow obstacles configured as side recesses or other vortices, wherein, however, for the purpose of optimizing the flow guidance between inlet and outlet, a cross-sectional change is optionally configured.

[0132] It can be seen in the cross-sectional view that the measuring channel 58 is configured with a substantially circular cross-section in the inlet region and the outlet region, which can be selected in correspondence with the pipe. With a rectangular cross-section (see Figure 6The actual measurement channel section 42 (top right) is configured centrally. According to the application, a reduction of the flow cross section can be provided in the region between the measurement channel section 42 and the inlet or outlet, respectively, so that the fluid flow is accelerated in this region and the cross section of the measurement channel 58 is then increased again relative to the reduction. As a result, the fluid flow in the actual measurement channel 58 is homogenized and vortexes are reduced, so that signal noise is minimized.

[0133] In the illustrated embodiment, the respective transition region of the flow cross section reduction is configured by a tapering (as seen in particular in the vertical cross-sectional view) of the two sides of the measurement channel insert 20 and is implemented in sections. This cross-sectional tapering is configured in particular in the transition region to the actual measurement channel section 42 between the fluid inlet insert 4 and the fluid outlet insert 6, which measurement channel section itself is defined by the measurement channel upper portion 44 and the measurement channel lower portion 46. The measurement beam is coupled in or out by the two notches 60, 62 configured in the measurement channel section 42. The reflectors 52a, 52b are then flushly inserted into diametrically opposite walls of the tapered section.

[0134] The third reflector 52c is arranged between the two notches 60, 62. In the illustrated embodiment, the net width of the measurement channel 58 is reduced again relative to the maximum diameter of the tapered section in this region, so that the flow is slightly accelerated in this region.

[0135] In the detail view shown in the lower right in Figure 6 In the illustrated view according to Figure 6 It can be seen very clearly in the illustrated view according to the application that the transitions to the inlet insert 4 and the outlet insert 6 and to the tapered region of the measurement channel section 42 are continuous, without a jump in cross section, so that an optimum flow is ensured.

[0136] Figure 7 A three-dimensional schematic of the channel design is shown, from which the positioning of the two sensors 22, 24 and the three reflectors 52a, 52b, 52c is derived. As explained, the W-shaped signal path 64 is set by the inclination adjustment of the sensors 22, 24 and by the positioning of the reflectors 52a, 52b, 52c described above, wherein the receivers are configured such that the measurement signal is reliably guided from the transmitter to the sensor (receiver) that receives the reflected measurement signal.

[0137] Again according to Figure 8The cross-sectional profile of the channel design is specified. Thus, the cross-section of the channel is approximately circular in the inlet region and the outlet region and then tapers towards the transition region, in which the circular cross-section transitions into an elongated, rectangular cross-section in which the vertical axis has a greater extension than the horizontal axis which extends perpendicular to the plane of the drawing. The cutouts 60, 62 are likewise configured circularly. The support surfaces of the reflectors 52a, 52b, 52c are implemented pocket-like, so that the reflectors 52a, 52b, 52c can be inserted flush into the measurement channel 58.

[0138] In the illustration according to Figure 8 It can also be seen very clearly in the illustration that the net width in the region of the measurement channel section 42 is smaller, so that the cross-section of the measurement channel 58 increases slightly towards the two transition regions. As described, in these two transition regions the cross-sectional profile changes continuously from the circular inlet insert 4 and the outlet insert 6 into the approximately rectangular measurement channel 58 which is rounded in the corner regions, wherein a cross-sectional reduction is provided for flow optimization in the transition regions.

[0139] The course of the W-shaped signal path 64 is shown again in Figure 9

[0140] As shown in Figure 10 The sensor distance, i.e. the distance between the center axes of the sensors 22, 24 and the geometry of the measurement channel 58 is designed so that, as shown in

[0141] If the reflecting surfaces of the reflectors 52a, 52b, 52c and / or the coupling surfaces of the sensors 22, 24 are concavely rounded according to Figure 11 and Figure 12 , the focusing of the measurement beam can be further improved, so that an optimal focusing of the measurement beam towards the reflectors 52a, 52b, 52c and the sensor 24 on the receiver side is ensured.

[0142] Figure 13 The geometry of the above-described measurement channel 58 and the obliquely arranged sensors 22, 24 and the W-shaped arrangement of the reflectors 52a, 52b, 52c as well as the cross-sectional changes which are designed for the homogenization of the fluid flow are shown again. In the embodiment shown in Figure 13 In the embodiment shown in

[0143] Figure 14 ​A further embodiment of the measuring channel insert 20 is shown, wherein the region which configures the actual measuring channel 58 is embodied integrally. Then, as in the above-mentioned embodiments, the inserts 4, 6 which configure the fluid inlet and the fluid outlet are again attached to the measuring channel insert 20. These inserts 4, 6 are again embodied identically in construction.

[0144] The installation is carried out as in the above-mentioned embodiments. First, the fluid inlet insert 4 and the fluid outlet insert 6 are inserted into the cast flow channel 10. Then, in a next installation step, the measuring channel section 42 is inserted into the flow channel 10 in a section-wise manner in the radial direction. The arrangement of the sensors 22, 24 and the reflectors 52a, 52b, 52c and the course of the measuring channel 58 correspond to the previously described embodiments, so that no further explanation is necessary.

[0145] Figure 15 An exploded view of a variant of the flowmeter 1 is shown, which corresponds in construction substantially to that of Figure 2 , wherein, however, the number of structural elements is reduced in relation to the above-mentioned solution. This is achieved, inter alia, in that the contact of the sensors 22, 24 is carried out by the formings 68, 70, wherein the sensors 22, 24 are bonded to the measuring channel insert 20, in particular to the measuring channel upper part 44.

[0146] The flowmeter 1 shown is composed in principle of a flow channel 10 made from cast material, on which a flange 18 with a recess 60 is configured. The inlet insert 4, the outlet insert 6, the measuring channel lower part 46 and the measuring channel upper part 44 are pushed through the recess, wherein, for the installation, the two inserts 4, 6 are moved in the radial direction towards the corresponding joints 12, 14. The connection of the flow channel 10 (housing) to the measuring channel insert 20 is carried out by connection bolts 80. The two sensors 22, 24 are inserted into the measuring channel upper part 44, wherein these are, for example, bonded. The contact is then achieved by the formings 68, 70, as explained, the free end sections of which are in contact with the previously described control unit 30. The control housing 32 is then fitted onto the measuring channel upper part 44, which itself can be provided with a housing cover 34, which releases the line of sight on the display (EDU) 74.

[0147] In Figure 16 , a view of the embodiment is shown, wherein the sensors (piezoelectric elements) 22, 24 are bonded to the multi-part measuring channel insert 20, wherein, in this embodiment, contact is made with the circuit traces 90, 92 by means of cables or (not shown) formings 68, 70.

[0148] Figure 17An embodiment of the flowmeter is shown, wherein the control unit 30 and the EDU (electronic display unit) 74 are clipped with Figure 4 the housing flange 28 of the measuring channel insert 20 shown.

[0149] As mentioned above, here the actual control unit 30 with the main PCB 72, the EDU 74 and if necessary a not shown communication module (see below implementation) is clipped with the aforementioned carrier structure 36, which itself is also provided with drying means 38, which are arranged on both sides of a battery 78 arranged on the underside of the PCB 72.

[0150] The carrier structure 36 is then fixed on the housing flange 28 of the measuring channel insert 20. This can also be achieved by a clip connection or by screwing or similar.

[0151] In a variant according to Figure 18 the connection of the control housing 8 with the housing flange 28 of the measuring channel insert 20 and the flange of the flow channel 10 is achieved by connection bolts 80, which pass through the housing flange 28 of the measuring channel insert 20 and the corresponding housing sections of the control housing 32 as well as the flange 18 and thus force-fit and form-fit positionally fix these components. The upper covering of the control housing 8 is achieved by the housing cover 34.

[0152] According to Figure 19 the housing cover 34 can be embodied as a cover, which is clipped with the control housing 32 and carries the characteristic data of the flowmeter 1. In an alternative variant shown in Figure 19 an information plate 48 of one type is inserted into the upwardly closed control housing 32.

[0153] Figure 20 Again a detail view of the flowmeter 1 with the measuring channel insert 20, the flow channel 10 and the control housing 8 fastened thereon is shown. The geometry of the measuring channel 58 has been explained before. It is learned from the illustration according to Figure 20 that for different nominal widths only the inlet insert 4 and the outlet insert 6 as well as the flow channel 10 have to be exchanged in principle.

[0154] In an embodiment according to Figure 21 the position fixing and contacting of the sensors 22, 24 is carried out by SMD spring contacts 82, which additionally after mounting are also positionally fixed by material fit, for example by thermal welding.

[0155] The SMD spring contacts 82 are according to Figure 21The SMD spring contacts are mounted in such a way that they load the sensors 22, 24 into a resting position in the recesses 59, 61 with pre-tensioning. After this tensioning, the SMD spring contacts 82 can then be thermally soldered in the predefined position. As will also be explained in more detail below, instead of spring contacts 82, contact pads without tensioning can also be used.

[0156] Figure 21 A possible installation sequence is shown. As indicated, in a first method step the sensors 22, 24 are placed into the measurement channel upper part 44. The spring contacts 82 are connected with the lines 54, 56 and are fitted onto the sensors 22, 24 as shown on the right in Figure 21 and are tensioned here below the side recesses, wherein the position of the spring contacts 82 is predefined by reference pins 86, which are embedded into corresponding reference notches 88 of the spring contacts 82.

[0157] In a next method step, a material-fit connection is achieved by thermal soldering. In principle, a spring pre-tensioning can of course also be dispensed with, as will be discussed next.

[0158] In a variant according to Figure 22 , the initially mentioned form bodies 68, 70 are used for the contact, which are inserted into the measurement channel insert 20, in particular into the housing flange 28, which accommodates the control unit 30. Here too, the position fixing can take place again by tensioning of the form bodies 68, 70 and / or material fit. As shown in Figure 22 , the form bodies 68, 70 are embodied with corresponding circuit traces 90, 92, which configure the corresponding signal and energy paths (64). The form bodies 68, 70 are here embodied approximately L-shaped with a flat base 94, the geometry of which approximately corresponds to the geometry of the spring contacts 82. Here, the circuit traces 90, 92 are embodied in such a way that they enable a large-area contact of the sensors 22, 24 along the pointing Figure 22 of the sensors 22, 24 to the observer. On the base 94, reference notches 88 are configured again, which are penetrated by housing-side reference pins 86. Contact arms 96 protrude from the base 94 respectively upwards towards the main PCB 72, wherein the free end sections of the contact arms 96 then rest on the corresponding contacts of the main PCB 72 to contact these. Here, the form bodies 68, 70 are embodied elastically, so that it is ensured that the contact rests optimally on the main PCB 72. In principle, this area can also be soldered or otherwise material-fit connected.

[0159] As explained, instead of the form bodies 68, 70, a cable or the like can also be used.

[0160] In Figure 22It can also be clearly seen that a housing seal 98 is arranged between the housing flange 28 of the measuring channel upper part 44 and the not shown control housing 32 on the housing flange 28, through which the control housing 8 is sealed.

[0161] In embodiments according to Figure 23 , the control unit 30 is also connected to the measuring channel insert 20, in particular to the measuring channel upper part 44, in a material-fit manner. In this embodiment, the sensors 22, 24 are bonded to the measuring channel insert 20 in the manner described above, wherein the contact is made by the shaped bodies 68, 70. In this embodiment, a support pin 100 is configured on the measuring channel upper part 44, which pin is embedded in a corresponding pin cutout 102 of the main PCB 72, wherein the position fixation is then made by thermal welding after placement. In a view according to Figure 23 , the structure of the control unit 30 is also seen, which will be explained in more detail below, with the main PCB 72, the battery 78 arranged thereunder (in a view according to Figure 23 ) and the EDU 74 and, if necessary, the communication unit arranged on the electric board. This will also be discussed in more detail below.

[0162] In Figure 24 , a further simplified embodiment is shown, in which a part of the measuring channel insert 20 and the flow channel 10, which at least partially accommodates this part, are configured in one piece.

[0163] As shown on the left side in Figure 24 , in a first manufacturing step, a type of outer cover (outer housing) is first manufactured by injection molding of a fiber-reinforced thermoplastic, on which the connecting pipes 12, 14, the base for accommodating the flange 18 of the control unit 30 and the space for partially accommodating the measuring channel insert 20 have already been configured.

[0164] In a second step, the reflector 52 is then inserted into this blank and, if necessary, further components are positioned, which are then injection-molded in a third method step with a standard plastic, which does not necessarily have to be configured as fiber-reinforced, wherein this injection-molding configures the profile / shaping of the above-mentioned measuring channel 58 (see Figures 7 to 15 ). In order to simplify the manufacturing, this plastic is implemented with a relatively low melting point, so that the fiber-reinforced plastic on the outside is not welded or melted.

[0165] This housing manufactured by injection molding largely corresponds to the aforementioned flow channel 10, into which the measuring channel insert 20 with the measuring channel upper part 44 is then inserted. The measuring channel lower part 46 can be said to be integrated in the housing (flow channel 10).

[0166] As a result, an arrangement is obtained which is manufactured in a two-stage molding process, which arrangement is composed in principle of the flow channel 10 and the measuring channel lower part 46. The fastening of the control unit 30 or control housing 8, the sensors 22, 24 and the molding bodies 68, 70 and the inserts 4, 6 is then carried out in the manner described above.

[0167] Figure 25 Again, a detail view is shown, from which the connection of the flow channel 10 (housing) with the measuring channel upper part 44 and the control housing 8 by means of the connecting bolts 80 results. As set out, the control housing 8 comprises the actual control unit 30 with the battery 78, the main PCB 72 and the EDU 74. The sensors are not visible in this sectional view. In correspondence therewith, the connection is achieved by means of the aforementioned connecting bolts 80, which pass through the mutually configured protrusions of the components (control housing 8, measuring channel insert 20, measuring channel upper part 44 and flow channel 10) and are sealed to the outside.

[0168] In Figure 26 a variant of the embodiment shown at the outset in Figure 4 is shown. In accordance with Figure 26 , the sensor holding part 26 is not screwed, but is positionally fixed in the flange of the measuring channel upper part 44 by means of the mating bolts 103. In addition, this embodiment corresponds to the embodiment according to Figure 4 , so that no further explanation is necessary.

[0169] As indicated in the view according to Figure 8 , the length L of the measuring channel, i.e. in principle the distance of the two notches 60, 62 or the sensors 22, 24, is relatively small in relation to conventional solutions. According to the application, the length of the measuring channel L (distance of the sensors 22, 24 or notches 60, 62) can be less than 40 mm, for example in the case of a nominal width DN of 110 or 80, wherein the gearing described at the outset is optimized in relation to conventional solutions.

[0170] Figure 27 A further embodiment of the flowmeter 1 according to the application is shown, which is relatively close to the previously described embodiments. In this flowmeter 1, too, a cast flow channel 10 with two connecting pipes 12, 14 is provided, on which a measuring housing 2 is attached. The measuring housing 2 has a control housing 8, which is conical towards the flow channel 10 (housing), for which more will be discussed in more detail below. A housing cover 34 or "top cover" is fitted onto the control housing 8, which is configured with a cover 104, which in the open state (view according to Figure 27 ) releases the line of sight to the display (EDU 74), from which only the display window 106 is visible in the illustration according to Figure 7 .

[0171] Further structural elements of the flowmeter 1 are formed by Figure 28 It can be seen that the figure also shows an exploded view of the flowmeter 1. The flow channel 10 has a tangentially arranged flange 18 with a notch 16. On the side of the flange 18 a guide 109 for a locking to be explained in more detail below is shown.

[0172] The measuring housing 2 is configured with a multipart measuring channel insert 20 which, in principle, consists of a measuring channel lower part 46, a measuring channel upper part 44, two inserts 4, 6 and a control housing 8 which together configure a peripheral wall portion of the measuring channel 58. As will also be described in more detail below, here the bottom of the control housing 8 together with the measuring channel upper part 44 and the measuring channel lower part 46 defines the measuring channel 58.

[0173] Inserted in the downwardly closed control housing 8 is the actual control unit 30 with a battery 78, a main PCB 72, an EDU 74 and a communication module 108. In the embodiment shown, the control housing 8 has a cover flange 110 on which a cover glass 112 is supported which is locked by means of a two-part mobile frame 114. The mobile frame surrounds both the cover flange 110 and the circumference of the cover glass 112 in the closed position, wherein the two mobile frame halves can be latched to one another so that the cover glass 112 is pressed against the end face of the cover flange 110 via a seal 116. The housing cover 34 with the cover 104 can also be positionally fixed by means of the mobile frame 114. As mentioned at the outset, the housing cover 34 can be provided with information about the flowmeter 1 and thus serves as a type of ID plate. The sealing of the measuring channel insert 20 relative to the flow channel 10 is likewise achieved by means of a seal 118.

[0174] A longitudinal section through the flowmeter 1 according to the installation Figure 29 is shown in Figure 27 and Figure 28 . In this illustration the control housing 8 which accommodates the control unit 30 can be seen. Here the battery 78 can be seen which is arranged on the underside of the main PCB 72 and thus supplies the electrical consumers with energy. The communication module 108 and the EDU 74 are arranged parallel to the main PCB 72, wherein they are covered by the cover glass 112. Both the EDU 74 and the communication module 108 are in contact with the main PCB 72 (also referred to as "meter board") so that these elements are controlled via the PCB 72.

[0175] As already mentioned above, the cover glass 112 is placed by means of the seal 116 on the cover flange 110 of the control housing 8 and is held in its nominal position by the latching movement of the frame 114, so that the control housing 8 is reliably covered upwards. As already mentioned above, in this embodiment the control housing 8 is configured with a closed bottom 120 on which two recesses 59, 61 are configured into which the ultrasonic sensors 22, 24 are inserted. In the shown embodiment these ultrasonic sensors are bonded with the bottom 120. As will also be explained in more detail later, the contacts are made via contact pads 124, 126, respectively, which are connected with the main PCB 72 via the cable / line 54 or via the previously described form bodies 68, 70 with the circuit traces 90, 92.

[0176] The measurement signals of the sensors 22, 24 are coupled directly through the bottom 120 of the control housing 8 into or out of the measurement channel 58. The end section of the bottom side of the control housing 8 is inserted into the recess 60 of the flange 18 of the flow channel 10, wherein the sealing is achieved by a further seal 118 which is arranged between the housing bottom or the adjoining peripheral wall of the control housing 8 and the flange 18. The control housing 8, in particular the bottom 120, is connected with the only sectionally visible measurement channel upper part 44 and the measurement channel lower part 46 which is shown in cross section. The structure of these components will be explained later with reference to Figures 30 to 36 The illustration according to Figure 29 As can be clearly seen in the illustration according to

[0177] The total length L of the measurement channel insert 20 with the two inserts 4, 6 and the measurement channel upper part 44 and the measurement channel lower part 46 is greater than the clear width L of the recess 16. The radial insertion can only be realized on the basis of the multi-part design of the measurement channel insert 20. The main advantage is that no compromises have to be made in terms of design as in the prior art, which has to be pushed in from the end side at the inlet or outlet. As can be gathered from the illustration according to Figure 29 In this embodiment, in the region of the two inserts 4, 6 there is also provided the described guide ribs 66 for flow optimization. The reflectors 52a, 52b, 52c can be connected with the measurement channel upper part 44 or the measurement channel lower part 46, for example, by injection molding in material fit.

[0178] The details of the structural elements of the measuring channel insert 20 are explained by means of the attached Figures 30 to 36 drawings. Figure 30 A top view of the control housing 8 is shown here, which is closed by a bottom 120 (away from the observer in the drawing) downwards. Figure 30 The control housing 8 is shown in a view towards the bottom 120. In the view according to Figure 31 , the cover flange 110 can be seen at the top, which has a receiving cavity 130 for the seal 116. As explained, two recesses 59, 61 are configured in the bottom 120, wherein the floor of the recesses is polished in order to guarantee an optimal coupling in and out of the measuring signal on the one hand and an optimal connection of the sensors 22, 24 placed on these floors on the other hand. Figure 30 On the large area of the bottom 120 visible in the Figure 31 , a measuring channel adapter 132 is arranged, which enables a form-fit connection to the measuring channel upper part 44 and the measuring channel lower part 46. For this purpose, the measuring channel adapter 132 is embodied with four mating notches 134 in the middle region, into which the corresponding mating elements of the measuring channel lower part 46 are embedded. On the side of the mating notches 134, a coupling-in face 136 or a coupling-out face 138 is configured, which can also be polished in order to optimize the signal quality. In the circumferential region of the measuring channel adapter 132, a step 140 is arranged for positioning the measuring channel upper part 44 and the measuring channel lower part 46, so that the structural elements of the measuring channel insert 20 can be mounted precisely fittingly.

[0179] Figure 32 and Figure 33 A view of the measuring channel upper part 44 attached to the measuring channel adapter 132 is shown. The measuring channel upper part 44 thus has two side walls 142, 144, which are connected to one another via a bracket 146. The reflector 52c is arranged between the two side walls 142, 144 on the bracket 146, wherein the reflector is preferably inlaid by injection molding. In the region of the side walls 142, 144, which are configured approximately with an L-shaped profile, respectively, through-openings 153a, 153b, 153c, 153d are configured, which are spaced apart in correspondence to the spacing of the mating notches 134. Along the bracket 146 and the side walls 142, 144, further mating elements are also arranged, which are configured in correspondence to the other contours of the measuring channel adapter 132 or the bottom 120 of the control housing 8, so that a precise fitting installation of the measuring channel upper part 44 is achieved.

[0180] Figure 34A top view of the measurement channel lower part 46 is shown, in which two reflectors 52a, 52b are embedded in the bottom surface 149 of the measurement channel lower part. The bottom surface 149 connects two walls 150, 152, which in the installed position (see Figure 29 ) enclose the two side walls 142, 144 of the measurement channel upper part 44. On the longitudinal edges of the walls 150, 152 that are directed toward the observer, there are four engagement pins 154a, 154b, 154c, 154d and further engagement protrusions 156a, 156b, which in the installed state pass through the openings 153a, 153b, 153c and 153d (the latter not visible) constructed on the side walls 142, 144 of the measurement channel upper part 44 and then embed into the engagement recesses 134a, 134b, 134c, 134d. Here, the engagement protrusions 156a, 156b embed into the lateral recesses 160a, 160b of the side walls 142, 144. The further relative positioning of the measurement channel upper part 44 relative to the measurement channel lower part 46 takes place via the engagement pins 162a, 162b, 162c, 162d of the measurement channel upper part 44, which engage into the corresponding slots 164a, 164b, 164c, 164d of the measurement channel lower part 46.

[0181] The two inserts 4, 6 form the closure of the inlet side and the outlet side of the measurement channel insert 20, which are constructed identically. These inserts 4, 6 have (as can also be seen from the cross-sectional view in Figure 29 ) a conically tapering tube 166, the diameter of which slightly decreases toward the actual measurement channel 58, wherein at least two guide ribs 66 are provided on the peripheral wall portion. At the end section facing the measurement channel upper part 44 / measurement channel lower part 46, there is provided a contour body 168, by which the circular cross section of the tube 166 is reduced to the rectangular cross section of the measurement channel 58. The contour body 168 also projects in the radial direction beyond the outer circumference of the tube 166 and thus serves as an axial stop when the insert 4, 6 is pushed into the region of the connecting tube 12, 14. As can be gathered from the cross-sectional view in Figure 29 , the end faces of the contour bodies 168 also rest in the installed state on a step 170 of the bottom 120, so that the measurement channel insert 20 is reliably positioned.

[0182] Figure 37 The open control housing 8 is shown in a view onto the bottom 120 with the two recesses 59, 61, into which the two sensors 22, 24 are inserted. As described above, the contact is achieved by means of the two contact pads 124, 126 and the not shown line 54 (cable) or the profile bodies 68, 70. The structure of the contact pads 124, 126 is illustrated by means of Figure 38 and Figure 39 .

[0183] Figure 38 A contact board 124 as used in embodiments according to Figure 37 is shown. The contact board 124 has a central contact 170 on which circuit tracks for contacting the sensor 22 are configured. The sensor 22 is embodied such that both electrodes 172, 174 are accessible over a large area visible in Figure 38 , so that contacting can be achieved by a corresponding design of the contact 170. This solution with electrodes 172, 174 configured on one side of the sensor 22 allows the latter to be simply connected by adhesive with the bottom 120 of the control housing 8 or the measuring channel insert 20, so that contacting then takes place from above, i.e. from the side facing away from the adhesive.

[0184] In the embodiment shown, the contact 170 with the circuit tracks configured thereon is connected by soldering or adhesive with the electrodes 172, 174, wherein the contact board 124 is precisely positioned by two board arms 176, 178 in which a mating recess 180, 182 is respectively provided, which is traversed in the correct reference position by a mating pin 154 provided in the recess 59, 61.

[0185] Figure 39 A variant of the embodiment according to Figure 38 is shown. In this embodiment, the contact board 124 is embodied with four board arms 176, 178, 184, 186 which are uniformly distributed on the circumference, in which a mating recess 188 is respectively provided, to which a corresponding mating pin 154 in the recess 59, 61 is assigned. With this solution, a more precise relative positioning of the sensors 22, 24 with respect to the contact boards 124, 126 and also with respect to the recesses 59, 61 can be achieved.

[0186] Especially in the case of small nominal widths and short measuring channel lengths (DN 15 / LL 80), it can be difficult to reach the connection pipes 12, 14 with the tools for connecting the flowmeter 1 with the pipe, since for example a spanner collides with the measuring housing 2. In order to simplify the attachment of a spanner or the like, it is provided in an alternative according to the application that the measuring housing 2 is conical towards the flow channel 10 according to the illustration in Figure 40 . In Figure 40 , two flowmeters are shown in an exploded view, in which the measuring housing 2 is not yet connected with the flow channel 10 (housing). The length I of the recess in the flange 18 also changes accordingly according to the length (LL 80 / LL 110), through which the measuring channel insert 20 visible in Figure 40 can be inserted. This is embodied according to the above-mentioned embodiments. As in the embodiment according to Figure 40As can be clearly seen in the view, the control housing 8 is conical in particular towards the connecting pipes 12, 14, wherein the wall faces 190, 192 arranged by the inclination of the control housing 8 simplify the attachment of the tool. Here, the greatest conicity is associated with the length of the flowmeter 1. In Figure 40 the embodiment shown on the left in Figure 40 c, the conicity is more strongly pronounced than in the case of the relatively long measuring channel 58 shown on the right in c. However, the problem described at the outset does not occur to such a great extent for such long measuring channels 58, since the connecting pipes 12, 14 then protrude axially beyond the control housing 8 and the attachment of the tool is thus simpler than in short flowmeters.

[0187] Figure 41 In principle, one also strives to install the largest possible battery 78, since the service life of the flowmeter 1 is then improved. One therefore seeks to use D single-cell batteries having improved capacity and performance instead of the conventional C single-cell batteries, but such D single-cell batteries are constructed significantly more voluminous than the more compact C single-cell batteries. This is shown clearly in Figure 41 c. In the upper region, a flowmeter having a relatively short length (LL80) is shown, wherein a C single-cell battery 78 is inserted into the conical control housing 8. This C single-cell battery is arranged in a manner known per se such that its longitudinal axis extends parallel to the throughflow direction of the measuring channel 58. That is to say, in the case of the flowmeter according to Figure 41 a, the longitudinal axis of the battery 78 is arranged parallel to the measuring channel axis. In the case of the flowmeter according to b, the longitudinal axis of the battery 78 is arranged transversely to the measuring channel axis.

[0188] In Figure 41 c, 41d, a corresponding illustration is shown having a D single-cell battery 78. Since these battery types are significantly more voluminous, the control housing 8 must also be constructed correspondingly voluminous. Furthermore, in most cases, the orientation of the battery 78 according to Figure 41 c and Figure 41 d must be changed, i.e. the longitudinal axis of the cylindrical D single-cell battery 78 is arranged transversely to the measuring channel axis. That is to say, in the case of the embodiment according to Figure 41 c and Figure 41 d, the battery 78 must be changed by 90° relative to the position of the battery 78 in the embodiment according to Figure 41 a and Figure 41 b. This is associated with significant additional expenditure, so that the change to other batteries in order to improve the service life is at the expense of certain disadvantages, which lie in the retrofitting of the control housing 8.

[0189] According to Figure 42The closure of the control housing 8 on the display side is briefly explained once again. As already mentioned above, the control unit 30 with the main PCB 72 and the EDU 74, which are not visible in this view, and the communication module 108 with the sensors 22, 24 and their contact elements are inserted into the interior space of the control housing 8 when the flowmeter 1 is installed. Then, in a next work step, the sealing 116 is placed into the cover flange 110, the cover glass 112 is fitted and, if necessary, also the housing cover 34 (top cover), wherein the housing cover can be, for example, latched with the cover flange 110 in order to pre-fix the cover glass 112 and the housing cover 34. Figure 42 b, the sealing 116 is placed into the cover flange 110, the cover glass 112 is fitted and, if necessary, also the housing cover 34 (top cover), wherein the housing cover can be, for example, latched with the cover flange 110 in order to pre-fix the cover glass 112 and the housing cover 34.

[0190] After the pre-installation, the moving frame 114 with its two frame parts is fitted over the cover flange 110 and the components mounted thereon and is pushed together until the two moving frame parts are latched with one another and the housing cover 34 and the cover glass 112 are positionally fixed.

[0191] The connection of the measuring housing 2 with the flow channel 10 is shown in Figure 43 . As already mentioned above, the measuring housing 2 is inserted together with the measuring channel insert 20 into the recess 16, wherein the bottom 120 of the control housing 8 rests on the flange 18 of the flow channel 10. Here, the moving frame 114 is, for example, not yet latched and also the two connection bolts 80 are not yet inserted. In a next work step, the latter are connected by pushing in with the connection bolts 80 for the force- and form-fit connection of the flow channel 10 with the measuring housing 2 or the control housing 8. In a last method step (on the right in Figure 43 ), the moving frame 114 is pushed together and latched as explained according to Figure 42 , so that all components of the flowmeter 1 are reliably positioned relative to one another.

[0192] For the case that the communication module 108 is provided and this should be provided with an efficient antenna 191, as shown in Figure 44 , this is preferably positioned in the control housing 8, that is to say below the cover glass 112. It is assumed that the antenna 191 is provided with an antenna winding 193, which is in contact with the communication module 108 or the communication board 194, respectively. Due to the relatively small construction space above the communication module 108 or the communication board 194, the integrated antenna 191 can be laid such that, despite the relatively large diameter of the antenna winding 193, the antenna can be positioned above the plane pre-set by the EDU 74 and the communication board 194. That is to say, according to the embodiment in Figure 44 , the antenna winding 193 is arranged in the area of the EDU 74 on the side. According to the embodiment in Figure 44In the embodiment to the right of the same, the antenna winding 193 is arranged in the area of the communication board 194, wherein the antenna conductor first extends in the side around the communication board 194 and the EDU 74 next to it.

[0193] In Figure 45 and Figure 46 alternative solutions are shown. In this variant, the antenna 191 does not have to be integrated flush, but can protrude beyond the control housing 8. The antenna winding 193 is arranged here perpendicular to the large area of the communication board 194, wherein, however, according to Figure 46 , in order to protect against external damage at the housing cover 34, which closes the control housing 8 (view according to Figure 46 ) upwards, an outwardly closed antenna receptacle 196 is implemented, into which the antenna winding 193 is embedded, so that the antenna 191 is covered outwardly, however, has the best transmission reception performance due to the perpendicular arrangement.

[0194] In this embodiment, the housing cover 34 is provided with a display window 106, wherein additionally a top cover 198 is also fitted on the housing cover 34, which functions for example as an ID plate or can be provided with other information. The top cover 198 has an opening 200, through which the antenna receptacle 196 together with the antenna winding 193 arranged therein extends. Furthermore, the embodiment shown in Figure 45 corresponds to the aforementioned embodiments, so that no further explanation is required.

[0195] In Figure 47 a further embodiment of the flowmeter 1 is shown, wherein in a variant of the above-mentioned embodiments the measuring channel upper part 44 can be said to be integrated into the control housing 8. In other words, in the embodiment according to Figure 47 the mating elements of the measuring channel upper part 44 are configured on the bottom part 120. These mating elements are exemplarily provided with the reference 200 in the illustration according to Figure 47 and complement the measuring channel 58 or the measuring channel insert 20 with the measuring channel lower part 46, which according to Figure 47 the illustration to the right is inserted into the recess 16 in the flange 18 of the flow channel 10. In this embodiment, the two reflectors 52a, 52b are then also provided in the measuring channel lower part 46, while the mating elements 200 also accommodate the reflector 52c, so that a W-shaped signal path 64 can again be realized.

[0196] The installation takes place analogously to the embodiments described above. In a first method step, the two inserts 4, 6 are inserted into the flow channel 10 through the gap 16 and moved in the axial direction towards the connecting pipes 12, 14, thus providing space for the insertion of the measuring channel insert 20, which has a measuring channel lower part 46 and a mating element 200 configured on the bottom 120 of the control housing 8. By the insertion, the elements (mating element 200 and measuring channel lower part 46) held on the control housing 8 complement the inserts 4, 6 to the measuring channel insert 20, wherein the sealing takes place outwardly through the seal 116.

[0197] In the case of a change in the nominal width, in principle only the flow channel 10 and the inserts 4, 6 have to be replaced, while the other components can be retained.

[0198] In the embodiments described above, the control housing 8 and the measuring channel insert 20 are made of a material different from the flow channel 10. The flow channel is usually made of a cast alloy, for example brass.

[0199] In the embodiments described above, the control housing 8 and the measuring channel insert 20 are made of a material different from the flow channel 10. The flow channel is usually made of a cast alloy, for example brass. Figure 48 , 49 An embodiment is shown in which the composite flow channel 10 is connected with the control housing 8, thus in principle providing a flowmeter 1 which is made of very light and resistant fiber-reinforced plastic or other composite material in the main structural elements. The manufacture of the flow channel 10 consisting of composite material can take place according to a multistage injection molding method, as described for example according to Figure 24 , without the need for additional embodiments.

[0200] In the embodiments described above, a separate profile 68, 70 is provided for each contact of the sensors 22, 24. In principle, these profiles 68, 70 can also be spliced into a contour piece, so that the two sensors 22, 24 are contacted by a common contour body, which is laid with different circuit traces 90, 92 in order to enable separate actuation of the sensors 22, 24.

[0201] A flowmeter with an optimized throughflow cross section is disclosed.

Claims

1. A flow meter having a flow channel (10) for attachment to a pipe through which a fluid flows, a measuring unit held in the flow channel, the measuring unit having at least two spaced-apart sensors (22, 24) configured as ultrasonic transducers, the sensors coupling their measurement signals into or out through at least one notch (16) in the flow channel (10), the flow meter having a control unit (30) housed in a control housing (8) for operating the sensors (22, 24) and for processing the measurement signals, wherein, In the flow channel (10), the measurement channel (58) is formed by a multi-piece measurement channel insert (20), characterized in that the multi-piece measurement channel insert has at least one upper measurement channel portion (44) and a lower measurement channel portion (46), the upper measurement channel portion and the lower measurement channel portion at least partially defining a measurement channel section (42), wherein the measurement channel insert (20) is configured to be inserted through the notch (16), wherein inlet and outlet inserts (4, 6) are configured to be inserted radially relative to the longitudinal axis of the flow channel (10) through the same notch (16), the inlet and outlet inserts being attached to the measurement channel section (42), wherein the length (L) of the measurement channel section (42) and the inserts (4, 6) is greater than the net width (I) of the notch (16).

2. The flow meter according to claim 1, wherein, The two inserts (4 and 6) have the same structure.

3. The flow meter according to claim 1 or 2, wherein, The lower portion (46) and / or the upper portion (44) of the measuring channel remain the same for different nominal widths (DN) of the flow channel (10), and only the inserts (4, 6) are adapted to the nominal width (DN) of the pipe and therefore to the nominal width of the flow channel (10).

4. The flow meter according to claim 2, wherein, The inlet and outlet inserts (4, 6) are provided with axial stops facing the lower part (46) or the upper part (44) of the measuring channel.

5. The flow meter according to claim 1 or 2, wherein, The inserts (4, 6) and the measurement channel section (42) are designed such that the reduction of the flow cross-section in the transition region from the fluid inlet and / or fluid outlet to the measurement channel (58) is implemented such that the fluid is accelerated in that region.

6. The flow meter according to claim 1 or 2, wherein, Guide ribs (66) are constructed in the region of the inlet and outlet inserts (4, 6) in the measurement channel (58).

7. The flow meter according to claim 1 or 2, wherein, The upper part (44) of the measuring channel has a housing flange (28), the control housing (8) is attached to the housing flange and the housing flange forms the bottom (120) of the control housing (8).

8. The flow meter according to claim 1 or 2, wherein, The upper part (44) and the lower part (46) of the measurement channel are attached to the bottom (120) of the control housing (8) and define the measurement channel section (42) on the circumferential side with the bottom.

9. The flow meter according to claim 8, wherein, The upper part (44) of the measurement channel, the lower part (46) of the measurement channel and the control housing (8) are shaped to fit each other and are positioned relative to each other by fitting parts / fitting notches (180, 182, 188, 190).

10. The flow meter according to claim 1 or 2, wherein, The measurement channel section (42) has a rectangular cross-section, wherein the width of the measurement channel (58) along the direction toward the control housing (8) is significantly greater than the width in the direction transverse to the control housing.

11. The flow meter according to claim 1 or 2, wherein, At a nominal width of DN110 or DN80, the length (L) of the measuring channel section (42) is less than 40 mm.

12. The flow meter according to claim 1 or 2, wherein, At least one reflector (52) is held in material fit on the lower part (46) and / or the upper part (44) of the measurement channel.

13. The flow meter according to claim 1 or 2, wherein, The sensors (22, 24) are fastened to the inclined support surface of the upper part (44) of the measurement channel or the bottom (120) of the control housing (8).

14. The flow meter according to claim 1 or 2, wherein, The sensors (22, 24) are fixed in position by means of material matching, bonding or pre-tightening.

15. The flow meter according to claim 1 or 2, wherein, The contact between the sensors (22, 24) and the main PCB (72) is made through a circuit (54) or through a plastic molded body (68, 70) with circuit traces (90, 92).

16. The flow meter according to claim 15, wherein, Each sensor (22, 24) is in contact with a contact plate (124, 126), which itself is in contact with the main PCB (72) via a line (54) or a plastic molded body (68, 70).

17. The flow meter according to claim 16, wherein, The contact plates (124, 126) are brazed or bonded to the sensors (22, 24), wherein the electrodes of the sensors are constructed in a large area away from the bottom (120) of the control housing (8) or the upper part (44) of the measurement channel and / or along the peripheral wall of the sensors (22, 24).

18. The flow meter according to claim 16 or 17, wherein, The contact plates (124, 126) are shaped to fit and positioned about the control housing (8) or the upper part (44) of the measurement channel via a reference notch (88) and a reference pin (86) inserted into the reference notch.

19. The flow meter according to claim 1 or 2, wherein, The control housing (8) has a housing cover (34) with a display (40).

20. The flow meter according to claim 19, wherein, The housing cover (34) is connected to the control housing (8) via a multi-piece movable frame (114).

21. The flow meter according to claim 1 or 2, wherein, The upper part (44), the lower part (46) of the measurement channel and the control housing (8) are also connected to the flow channel (10) by bolts or by snap-fit.

22. The flow meter according to claim 1 or 2, wherein, The control housing (8) is tapered toward the connecting pipes (12, 14) of the flow channel (10).

23. The flow meter according to claim 1 or 2, wherein, The measuring channel insert (20) and the flow channel (10) are made of plastic.

24. The flow meter according to claim 1 or 2, wherein, The battery (78) is contacted / secured on a large area of ​​the main PCB (72) facing the measurement channel insert (20).

25. The flow meter according to claim 24, wherein, The battery (78) is arranged in the control housing (8) with its longitudinal axis transverse to or parallel to the flow direction.

26. The flow meter according to claim 1 or 2, wherein, The control housing (8) houses a display unit (EDU) (74) and a communication module (108), which are arranged offset from the main PCB (72) at a parallel distance from the housing cover (34).

27. The flow meter according to claim 26, wherein, The communication module (108) is configured with an antenna (191) integrated into the control housing (8), which is covered by the housing cover (34).

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