flow meter

Abstract

A flow meter comprising: a flow tube element having a sensor generating a signal for measuring a flow of fluid through the flow tube element; an electronics housing comprising a mounting side releasably mounted directly or indirectly to the flow tube element, the electronics housing housing a battery and electronics, the electronics and / or the sensor being powered by the battery, the battery being located in a battery compartment, the battery compartment being arranged in an operational position within the electronics housing, the battery compartment being removable from the electronics housing through the mounting side when the electronics housing is detached from the flow tube element; a first tamper-resistant element arranged in the operational position between a first portion of the electronics and the battery compartment protecting the first portion from tampering; a second tamper-resistant element mounted directly or indirectly to the flow tube element independently of the electronics housing protecting a second portion of the electronics from tampering, such that the second portion and the second tamper-resistant element remain mounted to the flow tube element when the electronics housing is detached from the flow tube element.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to flow meters, in particular to battery-powered ultrasonic flow meters configured to measure high fluid flow and to automatically and wirelessly transmit consumption values. The type of flow meter covered by the present disclosure is an ultrasonic flow meter, a magnetic inductive flow meter, a vortex flow meter, a Coriolis mass flow meter or other type of flow meter. BACKGROUND

[0002] Large flow meters, typically used in commercial, municipal and / or industrial fields, are generally expensive because their large flow tubes are typically made of cast steel. Therefore, the lifetime is particularly important for such large flow meters. Currently, commercial, municipal and / or industrial customers are expecting battery-powered flow meters to have a lifetime of ten years or more.

[0003] It is well known that utility providers of water, natural gas and / or heat energy use Automatic Meter Reading (AMR) systems or Advanced Metering Infrastructure (AMI) systems to efficiently and reliably manage customer billing. Such systems can be referred to as "dedicated" meter reading systems. Dedicated meter reading systems are characterized by installing metering instruments at many locations and transmitting consumption data to a head-end system (HES) through wireless communication with a dedicated data collector. A single data collector can collect consumption data read by thousands of metering instruments. Multiple data collectors can be distributed in a city or region to cover all metering instruments located therein. Generally, since there is typically no opportunity to recharge or replace the metering instrument batteries, the metering instruments are used to wirelessly communicate with the data collectors using the unlicensed band in a way that saves as much of the metering instrument battery power as possible. Therefore, it is a continuing challenge to be able to guarantee a minimum battery life, for example at least 10 years, 15 years or preferably 20 years, for example at hourly or daily readings.

[0004] To reduce the cost of implementing and maintaining the infrastructure of dedicated data collectors, public cellular communication networks can be used instead of dedicated data collectors to collect consumption data. For example, the metering instruments can include a connection module (e.g. a modem) to connect to a low-power wide-area network (LPWAN) provided by a public cellular communication network, for example a Narrow Band Internet of Things (NB-IoT) or Long Term Evolution Machine Type Communication (LTE-M) network, for example LTE Cat NB1, LTE Cat NB2, LTE Cat M1 or LTE Cat M2. The frequency band used in such LPWAN is licensed, but has a large link budget. Therefore, it is desirable to provide a battery-powered metering instrument that is able to efficiently record consumption data through the LPWAN on a regular basis (e.g. hourly or daily) while guaranteeing a minimum lifetime (e.g. 8 or 10 years).

[0005] In contrast to "dedicated" meter reading systems that "own" (including lease) the data collector infrastructure, public cellular communication networks are part of "generic" meter reading systems, wherein the wireless communication infrastructure between the metering instruments and the HES (i.e. the LPWAN) is owned, maintained and controlled by external parties, such as mobile network operators (MNOs). With generic meter reading systems, the utility provider (UP) of water, natural gas and / or heat energy only owns (or leases), maintains and controls the metering instruments and the HES, but not the LPWAN between them.

[0006] Cellular communication, especially with "generic" meter reading systems using the low power wide area network (LPWAN) provided by public cellular communication networks (e.g. NB-IoT), is very challenging in terms of energy consumption. Therefore, there is a certain risk that large and expensive flow meters of commercial, municipal and / or industrial customers consume too much energy for radio transmission and have to be replaced prematurely. One solution to this problem is to recharge the battery by means of a cable and terminals leading from an external power source to the internal battery. However, this can lead to frequent charging over a period of time and degradation of the battery over time.

[0007] Another solution is to replace the battery only with a new one, but this means that the user or a service technician has to go deep inside the flow meter. But this brings other problems, namely on the one hand the opportunity to access electronic equipment that is subject to regulatory authorities and on the other hand the risk of possible tampering. For example, the patent document US 8,994,552 B2 describes an all-electric utility gas meter with a separate battery compartment that accommodates a replaceable battery. However, such a solution requires too many fundamental modifications to the applicant's typical cylindrical flow meter design.

[0008] It is common to prohibit access to or opening of the flow meter by using a non-replaceable battery to prevent tampering with the flow meter. However, the flow meter must be self-restricted in radio transmission to guarantee a minimum lifetime of the non-replaceable and non-rechargeable battery. SUMMARY

[0009] It is therefore an object of the present invention to provide a battery-powered flow meter that requires little radio transmission self-restriction and that can prevent tampering.

[0010] The battery of the flow meter according to the present disclosure is replaceable and its electronics are protected against tampering.

[0011] According to a first aspect of the present disclosure, there is provided a flow meter comprising: a flow tube element comprising a sensor configured and arranged to generate a signal for measuring a fluid flow through the flow tube element; and an electronics housing comprising a mounting side, wherein the mounting side is releasably directly or indirectly mounted to the flow tube element, wherein the electronics housing houses a battery and electronics, wherein the electronics and / or the sensor are powered by the battery. The flow meter is characterized in that the battery is located in a battery cartridge, wherein the battery cartridge is arranged in an operational position within the electronics housing and the battery cartridge is removable from the electronics housing through the mounting side when the electronics housing is detached from the flow tube element. The flow meter is further characterized in that a first tamper- resistant element is arranged between a first portion of the electronics and the battery cartridge in the operational position to protect the first portion of the electronics from tampering. The flow meter is further characterized in that a second tamper-resistant element is directly or indirectly mounted to the flow tube element independently of the electronics housing to protect a second portion of the electronics from tampering such that the second portion of the electronics and the second tamper-resistant element remain mounted to the flow tube element when the electronics housing is detached from the flow tube element.

[0012] By detaching the electronics housing from the flow tube element and removing the battery cartridge from the detached electronics housing, the battery of the flow meter can be easily and safely replaced. When the electronics housing is detached from the flow tube element, the battery cartridge can stick to the second tamper-resistant element and remain electrically connected to the second portion of the electronics. The battery cartridge can be easily unplugged for replacement. The battery cartridge can contain one or more batteries that can be fixed in the battery cartridge or removable from the battery cartridge. One or more or all of the batteries can be replaced or the battery cartridge can be replaced as a unit with one or more batteries therein.

[0013] Optionally, the second tamper-resistant element can be substantially cup-shaped and / or the second portion of the electronics can reside at least partially within a cavity of the flow tube element. The second tamper-resistant element can nest within the electronics housing as long as the electronics housing is mounted to the flow tube element.

[0014] Optionally, the first tamper-resistant element can be substantially disc-shaped and can separate a first cavity within the electronics housing from a second cavity within the electronics housing, wherein the first cavity is inaccessible and contains the first portion of the electronics, and wherein the second cavity is accessible through the mounting side and contains the removable battery cartridge. The first tamper-resistant element can include one or more openings through which an electrical connection between the battery and the first portion of the electronics can pass.

[0015] Optionally, a third cavity can be defined in the electronics housing between the battery compartment in the operational position and the mounting side of the electronics housing, wherein the second anti-tampering element and / or the second part of the electronics resides at least partially within the third cavity.

[0016] Optionally, the first part of the electronics can be located on a first printed circuit board (PCB), and wherein the second part of the electronics can be located on a second printed circuit board (PCB).

[0017] Optionally, the first PCB and / or the second PCB can be arranged parallel to each other and / or parallel to the mounting side of the electronics housing. Thus, the PCBs preferably extend in parallel planes, preferably parallel to the mounting side of the electronics housing. This has the advantage that the battery compartment is inserted into and removed from the electronics housing substantially perpendicular to the first PCB, so that the electrical connection can be achieved by one or more male connectors extending perpendicular to the first PCB. The male connector(s) can be contact blades or pins as part of the battery compartment. The first PCB can comprise corresponding female connector(s) for receiving the male connector(s) of the battery compartment. Alternatively or additionally, the first PCB can comprise male connector(s) and the battery compartment can comprise corresponding receiving female connector(s) for receiving the male connector(s) of the first PCB. The electrical connection between the first PCB and the battery compartment can also provide a frictional mechanical connection, which can be manually released when the battery compartment is manually pulled out of the electronics housing.

[0018] Optionally, the flow tube element comprises a metal body defining the flow tube, a pipe mounting flange, a sensor cavity accommodating a sensor, and a mounting portion on which the electronics housing is releasably mounted. Preferably, the pipe mounting flanges are arranged coaxially to each other, so that the flow tube defines a main flow direction. The electronics housing is preferably mounted substantially perpendicular to the main flow direction, so that the mounting side of the electronics housing faces a central flow axis of the flow tube element extending along the main flow direction.

[0019] Optionally, the second anti-tampering element can be fixed, directly or indirectly, to the body at the mounting portion of the body. Preferably, the second anti-tampering element is cup-shaped and mounted on a glass or plastic substrate having through electrical contacts. The substrate can be fixed to the flow tube element by a ring-shaped mount. The second anti-tampering element can be fixed to the substrate by a screw having a screw head at least partially sunk into the second anti-tampering element. The screw head can be covered by a security seal in the form of a frangible tag.

[0020] Optionally, the second part of the electronics can be positioned closer to the flow tube element than the first part of the electronics, where the battery box in the operational position is positioned between the first part of the electronics and the second part of the electronics. The electronics housing can preferably have a cup shape, which defines a longitudinal axis perpendicular to the mounting side and / or the main flow axis.

[0021] Optionally, the first tamper-proof element can be fixed within the electronics housing. Preferably, the first tamper-proof element is inserted into the electronics housing from a top side opposite the mounting side, wherein during manufacturing and assembly of the flow meter, after the first part of the electronics is fully equipped in the first cavity, the top side is closed by a closing lid. Preferably, the first tamper-proof element is placed on one or more support faces defined by the electronics housing in the second cavity and facing away from the mounting side.

[0022] Optionally, the battery box can define a desiccant cavity at least partially filled with a desiccant. This is particularly advantageous if the battery box is replaced as a whole unit, because the desiccant is automatically replaced each time the battery is replaced.

[0023] Optionally, the battery box can comprise an electrical connection that protrudes through an opening in the first tamper-proof element to connect to the first part of the electronics and through an opening in the second tamper-proof element to connect to the second part of the electronics. Thus, the second part of the electronics can be powered through the first part of the electronics and vice versa.

[0024] Optionally, the electronics housing can define at least one internal positive fit element that engages with at least one corresponding external positive fit element of the battery box for guiding the battery box in and out of the operational position in a well-defined manner. The form fit elements preferably extend along the longitudinal axis of the electronics housing, i.e. perpendicular to the mounting side. Preferably, an axial (upper) end of the one or more internal positive fit elements can define a support face for placing the first tamper-proof element.

[0025] Optionally, the second tamper-proof element defines at least one positive fit element that engages with at least one corresponding positive fit element of the battery box for guiding the electronics housing in a well-defined manner when the electronics housing is mounted to the flow tube element. The form fit elements preferably extend along the longitudinal axis of the electronics housing, i.e. perpendicular to the mounting side.

[0026] Optionally, the electronics housing can have a closure cap on the side opposite the mounting side and form a cup accessible only through the mounting side when the electronics housing is detached from the flow tube element. This has the advantage that the electronics housing cannot be opened as long as it is mounted to the flow tube element.

[0027] Optionally, the electronics housing can have a mounting flange on the mounting side of the electronics housing.

[0028] Optionally, the first part of the electronics can be configured to display the numerical value and / or to wirelessly transmit the numerical value to an automatic reading system, wherein the second part of the electronics is configured to receive and / or process the signals generated by the sensor.

[0029] Optionally, the flow meter can be an ultrasonic flow meter, wherein the sensor is an ultrasonic transducer. BRIEF DESCRIPTION OF DRAWINGS

[0030] Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

[0031] Figure 1 a first perspective view of one embodiment of a flow meter according to the present application is shown;

[0032] Figure 2 a perspective view of Figure 1 different perspectives of the flow meter shown;

[0033] Figure 3 a perspective view of Figure 1 and Figure 2 a longitudinal section view of the flow meter shown;

[0034] Figures 4a-4c a perspective view of Figures 1-3 a side view, a longitudinal section view and a detailed view of the flow meter shown;

[0035] Figure 5 a perspective view of Figures 1-3 and Figures 4a-4c the flow meter shown with the electronics housing detached and the battery compartment pulled out of its operating position for replacement;

[0036] Figures 6a-6c a perspective view, a side section view and a longitudinal section view along the plane A-A of the electronics housing of the flow meter shown in Figures 1-3 , Figures 4a-4c and Figure 5

[0037] Figure 7 a perspective view of Figures 1-3 , Figures 4a-4c , Figure 5 ​and Figures 6a-6c exploded view of the electronics housing of the flow meter shown in

[0038] Figures 8a-8c different perspective views of the electronics housing of the flow meter shown in Figures 1-3 、 Figures 4a-4c 、 Figure 5 、 Figures 6a-6c and Figure 7 different perspective views of the electronics housing of the flow meter shown in

[0039] Figures 9a-9c different perspective views of the second tamper-evident element of the flow meter shown in Figures 1-3 、 Figures 4a-4c 、 Figure 5 、 Figures 6a-6c 、 Figure 7 and Figures 8a-8c different perspective views of the second tamper-evident element of the flow meter shown in

[0040] Figure 10a 、 Figure 10b different perspective views of the battery compartment of the flow meter shown in Figures 1-3 、 Figures 4a-4c 、 Figure 5 、 Figures 6a-6c 、 Figure 7 、 Figures 8a-8c and Figures 9a-9c different perspective views of the battery compartment of the flow meter shown in

[0041] wherein the list of reference signs is as follows:

[0042] 1 flow meter

[0043] 3 flow tube element

[0044] 5 electronics housing

[0045] 7 sensor

[0046] 9 fluid inlet end

[0047] 11 fluid outlet end

[0048] 13 central flow section

[0049] 15 mounting side of the electronics housing

[0050] 17 closure cap

[0051] 18 display

[0052] 19 electrical connection socket

[0053] 21 battery

[0054] 23 first PCB

[0055] 25 second PCB

[0056] 27 top section of electronics housing

[0057] 29 bottom section of electronics housing

[0058] 31 central section of electronics housing

[0059] 33 battery compartment

[0060] 35 first tamper-evident element

[0061] 37 first cavity of electronics housing

[0062] 39 second cavity of electronics housing

[0063] 41 second tamper-evident element

[0064] 43 third cavity of electronics housing

[0065] 45 body of flow tube element

[0066] 47 mounting section of body of flow tube element

[0067] 49 mounting base

[0068] 51 electrical contact / lead

[0069] 53 anchoring element

[0070] 55 fixing screw

[0071] 57 safety seal

[0072] 59 internal positive fit element of electronics housing

[0073] 61 external positive fit element of battery compartment

[0074] 63 contact blade

[0075] 65 female receiver

[0076] 66 opening in first tamper-evident element

[0077] 67 positive fit element of second tamper-evident element

[0078] 68 electrical connection

[0079] 69 positive fit element of battery compartment

[0080] 71 hook

[0081] 73 O-ring

[0082] 75 screw

[0083] 77 support surface

[0084] 79 desiccant cavity DETAILED DESCRIPTION

[0085] Figure 1 and Figure 2 A flow meter 1 in the form of a large ultrasonic flow meter is shown for measuring high fluid flow and for automatically wirelessly transmitting consumption values. The flow meter 1 includes a flow tube element 3 and an electronics housing 5 releasably mounted to the flow tube element 3. The flow tube element 3 includes sensors 7 in the form of ultrasonic transducers configured and arranged to generate signals for measuring fluid flow through the flow tube element 3.

[0086] For ease of spatial orientation, each figure shows a local right-hand Cartesian coordinate system. The local coordinate system shown refers to the operating position when all components are mounted and assembled for operation as shown in Figure 1 , Figure 3 and Figures 4a-4c It should be understood that the flow meter 1 can be mounted in any spatial orientation. However, for ease of description by using spatial terms such as "up", "down", "axial" and "lateral", the z-axis should point vertically upward, the x-axis should point horizontally along the main flow direction L through the flow tube element 3, and the y-axis should point horizontally perpendicular to the main flow direction L.

[0087] The flow tube element 3 defines a main flow direction L extending from a fluid inlet end 9 of the flow tube element 3 to a fluid outlet end 11 of the flow tube element 3. The fluid inlet end 9 and the fluid outlet end 11 are coaxially aligned with each other and with the main flow direction L. Each of the fluid inlet end 9 and the fluid outlet end 11 includes a connecting flange for connecting a fluid conduit (not shown) to the flow tube element 3. The flow tube element 3 further defines a central flow section 13 located between the fluid inlet end 9 and the fluid outlet end 11. The inner diameter of the central flow section 13 is smaller than the inner diameter of the fluid inlet end 9 and the fluid outlet end 11 (see Figure 3 ). Thus, the cross section of the fluid flow through the flow tube element 3 is defined by the central flow section 13, where the cross section is smallest along the flow tube element 3.

[0088] The sensors 7 are arranged in dedicated sensor cavities defined on opposite lateral sides of the flow tube element 3. In the shown embodiment, the flow tube element 3 includes two pairs of ultrasonic transducers, namely an upper pair and a lower pair. Each pair of ultrasonic transducers faces each other from opposite lateral sides of the flow tube element 3, where the pair of ultrasonic transducers defines a main ultrasonic travel axis S pointing diagonally in the xy-plane.

[0089] Thereby, depending on the flow direction along the S-axis, the ultrasonic signals exchanged between the pair of ultrasonic transducers along the main ultrasonic travel axis S have a component of motion along the main flow direction L or in the opposite direction thereof. Thus, as known to the skilled person, the flow velocity can be determined from the ultrasonic signals. Since the inner cross section of the central flow section 13 is known, the fluid flow through the flow tube element 3 can be derived from the flow velocity. The fluid flow can be recorded in a continuous, regular and / or sporadic manner over a certain time period in order to determine the consumption, i.e. the total volume that has flown through the flow tube element 3 over a certain time period. The reception, processing, storage and / or transmission of data is performed by the electronics located in the electronics housing 5.

[0090] The electronics housing 5 is mounted on the top side of the central flow section 13 of the flow tube element 3. Thus, the electronics housing 5 has a mounting side 15 at its bottom. In the shown embodiment, the electronics housing 5 has a substantially cylindrical shape with a vertical longitudinal axis (along the z-axis). Thus, the horizontal cross-sectional shape of the electronics housing 5 is substantially circular.

[0091] The electronics housing 5 cannot be opened when it is not detached from the flow tube element 3. The top side of the electronics housing is closed by a closure cap 17. The front face of the closure cap 17 is at least partially transparent to allow visual inspection of a display 18 located underneath. The electronics housing 5 further comprises an electrical connection socket 19 located at the axial top side of the electronics housing 5. The electrical connection socket 19 allows connection of an external power supply (not shown) to be optionally connected during maintenance and / or during expected high electrical energy consumption. The electrical connection socket 19 can also provide the option to extract data for further processing and / or transmission; and / or to set parameters; and / or to upload programs or program updates.

[0092] During normal operation of the flow meter 1, the flow meter 1 is powered by a battery and is independent of an external power supply. The electrical connection socket 19 is not used during normal operation of the flow meter 1.

[0093] As Figure 3As shown, the electronics housing 5 accommodates two batteries 21 in the form of D-cells. The electronics housing 5 further accommodates electronics located on two separate printed circuit boards (PCBs) 23, 25. The first PCB 23 extends in the horizontal xy-plane in the top section 27 of the electronics housing 5. The first PCB 23 contains a first portion of the electronics in the electronics housing 5. The display 18 is a component of the first portion of the electronics on the first PCB 23. Preferably, the first PCB 23 also comprises a signal transmitter and antenna and / or antenna connector for wireless transmission of the consumption value to an automatic reading system (not shown). The second PCB 25 extends in the horizontal xy-plane parallel to the first PCB 23 in the bottom section 29 of the electronics housing 5. The batteries 21 are located in a battery compartment 33 arranged in a central section 31 of the electronics housing 5 between the top section 27 and the bottom section 29 of the electronics housing 5. Thus, the battery compartment 33 is located within the electronics housing 5 between the first PCB 23 and the second PCB 25. This is the operational position of the battery compartment 33 when the electronics housing 5 is mounted to the flow tube element 3, as Figure 3 shown. As Figure 5 shown and described below, the battery compartment 33 can be removed from the electronics housing 5 through the bottom mounting side 15 of the electronics housing 5 when the electronics housing 5 is detached from the flow tube element 3.

[0094] A first tamper-proofing element 35 is located within the electronics housing 5 below the first PCB 23. The PCB 23 is free of electronics on its underside (facing the tamper-proofing plate), at least in its middle section, in order to free up space for the first tamper-proofing element 35 and the batteries 21 (see Figure 6c ). The first tamper-proofing element 35 is essentially disc-shaped and extends essentially in the horizontal xy-plane between the battery compartment 33 and the first PCB 23. The first tamper-proofing element 35 separates a first cavity 37 within the top section 27 of the electronics housing 5 from a second cavity 39 within the central section 31 of the electronics housing 5. The first tamper-proofing element 35 is made as a thin plate in order to make the increase in height of the electronics housing 5 as small as possible (see Figure 7 ). The first cavity 37 contains the first PCB 23 with the first portion of the electronics. The first tamper-proofing element 25 prevents access to the first cavity 37 from below. The second cavity 39 contains the removable battery compartment 33 and can be accessed through the bottom mounting side 15 of the electronics housing 5 when the electronics housing 5 is detached from the flow tube element 3.

[0095] The second PCB 25 contains a second portion of the electronics in the electronics housing 5, wherein the second portion of the electronics comprises electronic components for receiving and processing signals generated by the sensor 7. The electronics on the second PCB 25 are protected from tampering by a second tamperproofing element 41 mounted to the flow tube element 3 independently of the electronics housing 5. Thereby, when the electronics housing 5 is detached from the flow tube element 3, the second PCB 25 and the second tamperproofing element 41 remain mounted to the flow tube element 3. The second tamperproofing element 41 is substantially cup-shaped and nests in a third cavity 43 in the bottom section 29 of the electronics housing 5. The third cavity 43 of the electronics housing 5 is defined in the electronics housing 5 between the battery compartment 33 and the mounting side 15 of the electronics housing 5. The second tamperproofing element 41 and the second portion of the electronics on the second PCB 25 are at least partially located within the third cavity 43 of the electronics housing 5. The second tamperproofing element 41 substantially fills the third cavity 43 within the bottom section 29 of the electronics housing 5.

[0096] Figures 4a-4c It is shown how the second tamperproofing element 41 is securely mounted to the flow tube element 3. The flow tube element 3 comprises a steel main body 45 defining an upper mounting portion 47. The flow tube element 3 is further equipped with a mounting base 49 in the form of a frame glass plate which is fixed to the mounting portion 47 of the main body 45. The mounting base 49 comprises vertical electrical contacts 51 for establishing an electrical connection between the sensor 7 and the bottom of the second PCB 25. An anchor element 53 protrudes vertically through the mounting base 49 from below to receive a fixing screw 55 at its top end. The anchor element 53 also protrudes through the second PCB 25 with its top end. The head of the fixing screw 55 pushes the second tamperproofing element 41 down onto the second PCB 25 and secures the second tamperproofing element 41 and the second PCB 25 to the mounting base 49 through the anchor element 53. The head of the fixing screw 55 sinks into the second tamperproofing element 41 so that a security seal 57 in the form of a frangible label can be placed on the second tamperproofing element 41 to indicate that the fixing screw 55 has not been tampered with. A broken security seal 57 indicates that the fixing screw 55 can have been unscrewed in order to remove the second tamperproofing element 41 to access the electronics on the second PCB 25. The fixing screw 55 also has the additional function of establishing an electrical ground connection between the PCB 25 and the metal main body 45 of the flow tube element 3. This electrical ground connection is relevant for EMC protection and for passing electrical approval tests for ultrasonic flow meters.

[0097] Figure 5This illustrates how to remove the battery case 33 from the electronic housing 5. Preferably, the fully assembled battery case 33 is replaced as a single unit. The electronic housing 5 is detached from the mounting base 49 of the flow tube element 3 and pulled vertically out of the flow tube element 3. This makes the third cavity 43 in the bottom section 29 of the electronic housing 5 accessible via the bottom mounting side 15 of the electronic housing 5. The second PCB 25 remains at the flow tube element 3 and is protected against tampering by the second tamper-proof element 41 fixed to the mounting base 49 of the flow tube element 3. The battery case 33 can now be pulled out of the mounting side 15 of the electronic housing 5 and replaced with another battery case 33 equipped with a new battery 21. The battery case 33 can be replaced by hand; that is, after lifting the electronic housing 5, the battery case 33 can be removed by hand. Depending on whether the frictional contact between the battery box 33 and the second tamper-proof element 41 and / or the electrical connection with the second PCB 25 is less than or greater than the frictional contact between the battery box 33 and the electronic device housing 5 and / or the electrical connection with the first PCB 23, the battery box 33 may be pulled out of the flow tube element 3 together with the electronic device housing 5, or may remain on the flow tube element 3 while the electronic device housing 5 is being pulled out. In the latter case, the battery box 33 can be easily and manually removed from the flow tube element 3 for replacement.

[0098] In the illustrated embodiment, the electronics housing 5 defines three internal positive-fit elements 59 in the form of longitudinal ribs extending along the z-axis. The battery case 33 includes a corresponding external positive-fit element 61 in the form of a longitudinal slot extending along the z-axis. This effectively defines the rotational direction of the battery case 33 relative to the electronics housing 5 in the xy plane, ensuring that the battery case 33 is in close contact with the first PCB 23 located within the first cavity 37 of the electronics housing 5. Figure 5 There are designated electrical and mechanical contacts between the first parts of an electronic device (not visible in the image). For example... Figure 5 As shown, a first portion of the electronics on the first PCB 23 is protected against tampering by a first tamper-proof element 35. The battery case 33 includes a contact blade 63 extending vertically upwards from its top side for cutting into a female receiver 65 disposed on the first PCB 23. The first tamper-proof element 35 has an opening 66 to allow the contact blade 63 to cut into the female receiver 65 of the first PCB 23. The battery case 33 also includes a vertically penetrating electrical connection 68 for electrically connecting the first PCB 23 to the second PCB 25. Both the first PCB 23 and the second PCB 25 include connection sockets for receiving pins of the electrical connection 68 of the battery case 33 to be inserted. Software code in the electronics of the first PCB 23 and the second PCB 25 is activated to ensure that these PCBs 23 and 25 remain a mating pair after the battery case 33 is replaced.

[0099] Once the new battery box 33 is inserted and plugged in the electronics housing 5, the electronics housing 5 can be mounted to the flow tube element 3. To guide the electronics housing 5 in a well-defined way with respect to the rotational direction in the xy-plane relative to the flow tube element 3, in the shown embodiment the second tamper-proof element 41 defines two male mating elements 67 that engage with two corresponding female mating elements 69 of the battery box 33. The male mating elements 67 of the second tamper-proof element 41 are formed as vertically extending webs that should protrude into the vertically extending slot-shaped mating elements 69 at the lateral sides of the battery box 33.

[0100] As Figures 6a-6c shown, the second tamper-proof element 41 also comprises hooks 71 that snap under the second PCB 25 in order to protect the second part of the electronics on the second PCB from lateral tampering attacks. Figure 6c It is also clearly shown that the through-going electrical connections 68 are provided in the battery box 33, so that the second PCB 25 and the sensor 7 are powered by the battery 21 via the first PCB 23 and the electrical connections 68. Figure 7 The individual components of the electronics housing 5, the battery box 33 and the mounting base 49 are shown. The mounting base 49 is divided in a glass plate and a mounting frame in Figure 7 . There are also eight electrical contacts 51 in the form of pins that are provided through the glass plate of the mounting base 49, i.e. two pins 51 for one ultrasonic transducer. The second PCB 25 has corresponding contacts on its bottom side for contacting the pins 51.

[0101] The electronics housing 5 is water-tightly sealed at the top side and the bottom mounting side 15 by O-rings 73. The upper O-ring 73 is pressed against the upper rim of the electronics housing 5 by the closing lid 17. The lower O-ring is pressed downwards against the glass plate of the mounting base 49 by the bottom mounting side 15 of the electronics housing 5 when the electronics housing 5 is fastened to the mounting base 49 by screws 75. Instead of said fixing screws 75, the electronics housing 5 can also be screwed and fixed in corresponding threads on the mounting base 49.

[0102] Figure 8a The electronics housing 5 is shown separately without any components mounted. As shown, the axial top end of each of the three internal male mating elements 59 provides a support face 77 facing upwards against the bottom mounting side 15. As Figure 8b shown, the first tamper-proof element 35 is placed on these support faces 77. Thus during assembly, the first tamper-proof element 35 is inserted into the electronics housing 5 as a first component from the open top side. The mounting of the first PCB 23 and the closing of the top side by the closing lid 17 follow later during assembly.

[0103] Figures 9a-9c The second tamper-evident element 41 is shown in more detail. Figure 9a A perspective bottom view of the second tamper-evident element 41 shows in particular how the second tamper-evident element 41 is fixed by means of the fixing screw 55 and the hook 71. Figure 9b The second tamper-evident element 41 is shown with the security seal 57 in the form of a frangible label affixed to it to cover the head of the fixing screw 55. Figure 9c The second tamper-evident element 41 is shown before the security seal 57 is affixed, so the head of the fixing screw 55 is visible.

[0104] Figure 10a 、 Figure 10b The battery compartment 33 is shown without the battery 21. In particular, as shown in Figure 10b The battery compartment 33 defines a desiccant cavity 79 located on the side of the battery 21. The desiccant cavity 79 is at least partially filled with desiccant during assembly. The desiccant can be packaged, or poured into the desiccant cavity 79 in bulk. If not packaged, it is advantageous for the desiccant cavity 79 to be an enclosed cavity for safely containing the desiccant as a whole. The desiccant cavity 79 of the battery compartment 33 is very useful because it is replaced together with the battery 21 as a unit, so the desiccant is automatically replaced each time the battery is replaced. It is also useful for storage and transportation of the battery compartment 33 as a spare part for the flow meter 1.

[0105] Any whole or element of the foregoing description having a known, obvious, or foreseeable equivalent should be incorporated by reference from this document as if individually set forth. The true scope of the present disclosure should be determined by reference to the appended claims, which should be construed as encompassing any such equivalents. The reader should also recognize that elements described as optional, preferred, advantageous, convenient, etc. are optional, and do not limit the scope of the independent claims.

[0106] The above-described embodiments will be understood as illustrative examples of the present disclosure. It should be appreciated that any feature described with respect to any one embodiment can be used in combination with any other feature described with respect to any other embodiment, and can also be used in combination with one or more features of any other aspect or embodiment, or any combination of any other embodiments. While at least one exemplary embodiment has been shown and described, it is to be understood that other modifications, substitutions, and alternatives might be apparent to one of ordinary skill in the art and can be made without departing from the scope of the subject matter described herein, and that this application is intended to cover any and all such adaptations or variations.

[0107] Furthermore, "comprising" does not exclude other elements or steps and "a" or "an" does not exclude a plurality. Also, any reference signs in the claims should not be construed as limiting the scope of the claims. The mere fact that different representative embodiments as to the inventive subject matter can have employed, for didactic purposes, different terminology does not constitute a disclaimer of all but that terminology. It is to be understood that any such modifications, alternatives, and substitutions are to be considered as falling within the scope of the present disclosure. The disclosure is not to be limited to the details given in the foregoing description. Various other modifications and implementations that are within the scope of the disclosed concept will occur to those skilled in the art upon reading the description of the application. The disclosures and the descriptions of features or techniques in this document are not mutually exclusive, but can be combined in any manner.

Claims

1. A flow meter (1) comprising: - a flow tube element (3) comprising a sensor (7) configured and arranged to generate a signal for measuring a flow of fluid through the flow tube element (3); and - an electronics housing (5) comprising a mounting side (15), wherein the mounting side (15) is releasably mounted directly or indirectly to the flow tube element (3), wherein the electronics housing (5) houses a battery (21) and electronics, wherein the electronics and / or the sensor (7) are powered by the battery (21), characterized in that the battery (21) is located in a battery box (33), wherein the battery box (33) is arranged in an operating position within the electronics housing (5) and the battery box is removable from the electronics housing (5) through the mounting side (15) when the electronics housing (5) is detached from the flow tube element (3); a first portion of the electronics is protected from tampering by a first tamper-proof element (35) arranged in the operating position between the first portion of the electronics and the battery box (33); and a second portion of the electronics is protected from tampering by a second tamper-proof element (41) mounted directly or indirectly to the flow tube element (3) independently from the electronics housing (5) such that the second portion of the electronics and the second tamper-proof element (41) remain mounted to the flow tube element (3) when the electronics housing (5) is detached from the flow tube element (3).

2. The flow meter (1) of claim 1, wherein, The second tamper-proof element (41) is substantially cup-shaped and / or the second portion of the electronics is at least partially located within a cavity of the flow tube element (3).

3. The flow meter (1) of claim 1, wherein, The first tamper-proof element (35) is substantially disc-shaped and separates a first cavity (37) within the electronics housing (5) from a second cavity (39) within the electronics housing (5), wherein the first cavity (37) is inaccessible and contains the first portion of the electronics, and wherein the second cavity (39) is accessible through the mounting side and contains the battery box (33) which is removable.

4. The flow meter of claim 3, wherein, In the electronics housing (5), a third cavity (43) is defined between the battery box (33) in the operating position and the mounting side (15) of the electronics housing (5), wherein the second tamper-proof element (41) and / or the second portion of the electronics is at least partially located within the third cavity (43).

5. The flow meter (1) of claim 1, wherein, The first portion of the electronics is located on a first printed circuit board, PCB, (23) and wherein the second portion of the electronics is located on a second printed circuit board, PCB, (25).

6. The flow meter (1) of claim 5, wherein, The first printed circuit board, PCB, (23) and / or the second printed circuit board, PCB, (25) are arranged parallel to each other and / or parallel to the mounting side (15) of the electronics housing (5).

7. The flow meter (1) according to any one of claims 1 to 6, wherein The flow tube element (3) comprises a metal main body (45) defining a flow tube, a pipe mounting flange, a sensor cavity housing the sensor (7) and a mounting portion (47) to which the electronics housing (5) is releasably mounted.

8. The flow meter (1) of claim 7, wherein, The second tamper-proof element (41) is directly or indirectly fixed to the main body (45) at the mounting portion (47) of the main body (45).

9. The flow meter (1) according to any one of claims 1 to 6, wherein The second portion of the electronics is positioned closer to the flow tube element (3) than the first portion of the electronics, wherein the battery compartment (33) in the operating position is positioned between the first portion of the electronics and the second portion of the electronics.

10. The flow meter (1) according to any one of claims 1 to 6, wherein The first tamper-proof element (35) is fixed inside the electronics housing (5).

11. The flow meter (1) according to any one of claims 1 to 6, wherein The battery compartment (33) defines a desiccant cavity (77) which is at least partially filled with a desiccant.

12. The flow meter (1) according to any one of claims 1 to 6, wherein The battery compartment (33) comprises an electrical connection portion (68) which protrudes through an opening in the first tamper-proof element (35) to connect to the first portion of the electronics and through an opening in the second tamper-proof element (41) to connect to the second portion of the electronics.

13. The flow meter (1) according to any one of claims 1 to 6, wherein The electronics housing (5) defines at least one internal positive fit element (59) which engages with at least one corresponding external positive fit element (61) of the battery compartment (33) for guiding the battery compartment (33) in and out of the operating position in a well-defined manner.

14. The flow meter (1) according to any one of claims 1 to 6, wherein The second tamper-proof element (41) defines at least one positive fit element which engages with at least one corresponding positive fit element of the battery compartment (33) for guiding the electronics housing (5) in a well-defined manner when the electronics housing (5) is mounted to the flow tube element (3).

15. The flow meter (1) according to any one of claims 1 to 6, wherein The electronics housing (5) has a closure cap (17) on a side opposite the mounting side and forms a cup which can only be accessed through the mounting side (15) when the electronics housing (5) is detached from the flow tube element (3).

16. The flow meter (1) according to any one of claims 1 to 6, wherein The electronics housing (5) has a mounting flange on the mounting side (15) of the electronics housing (5).

17. The flow meter (1) according to any one of claims 1 to 6, wherein The first portion of the electronics is configured to display a numerical value and / or to wirelessly transmit a numerical value to an automatic reading system, and wherein the second portion of the electronics is configured to receive and / or process a signal generated by the sensor (7).

18. The flow meter (1) according to any one of claims 1 to 6, wherein The flow meter (1) is an ultrasonic flow meter, and wherein the sensor (7) is an ultrasonic transducer.

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