EP3990869A1

EP3990869A1 - Flexible flow sensor

Info

Publication number: EP3990869A1
Application number: EP20734036.5A
Authority: EP
Inventors: Richard Jonathan GINUS; Matthijs Johannes BUURON
Original assignee: Pipelife Nederland BV
Current assignee: Pipelife Nederland BV
Priority date: 2019-06-26
Filing date: 2020-06-24
Publication date: 2022-05-04
Also published as: WO2020260401A1; NL2023383B1

Abstract

A flow sensor comprises a flexible strip for insertion into a flow in a flow system; a magnet located at a distal end of the flexible strip; and a sensor element connected to the proximal end of the flexible strip for sensing a bend of the flexible strip.

Description

Flexible Flow Sensor

Technical field

The invention relates to flow sensors to sense flow, for example through a pipe.

Background art

Flow sensors or meters can be used in many different contexts for the measurement of fluid flow. The measurements can be related to the rate, direction, volume and/or other factors related to the flow through various systems.

When measuring flow through pipe systems, a flow meter is often located in a branch off the main pipe. Flow is directed toward this branch, and the flow meter can then sense the flow rate in different manners depending on the sensor type. One type of flow meter is an ultrasonic flow meter, which measures the velocity of a fluid along a flow path with ultrasound. The ultrasound beam is directed into the flow, and the difference in measured transit time between pulses of beam is used to estimate the flow rate. These flow meters are affected by the acoustic properties of the fluid, as well as the temperature, density, viscosity and suspended particles. Thus, they are often less accurate than desired.

Summary

A flow sensor includes a flexible strip for insertion into a flow in a flow system; a magnet located at a distal end of the flexible strip; and a sensor element connected to the proximal end of the flexible strip for sensing a bend of the flexible strip. Such a flow sensor provides a simple yet effective way to measure flow in a variety of flow conditions. The minimal parts and flexible strip with sensor element allows provides a durable system for a simple mechanical measure of flow direction and/or rate that is reliable even in low flow conditions. Such a simple yet durable system allows for the placement in systems that are not too easily accessible, such as underground pipes, as the system can be relied upon with minimal maintenance and/or access for repair, replacement or inspection needed.

According to an embodiment, the sensor element comprises a magnetometer. Optionally, magnetometer can measure the change in magnetic field due to the movement of the magnet; and the measured data is converted to a flow direction and rate. The conversion to flow direction can be determined by a simple measurement of the way of bending of the flexible strip. The flow rate can be related to the specific amount of bending sensed by the magnetometer. Such a system provides a simple and effective way to determine flow rate and/or flow direction through a flow system.

According to an embodiment, the flow system is a pipe and the flexible strip is inserted into the pipe perpendicularly to the direction of flow through the pipe. Insertion perpendicularly ensures that the flow acts on the part of the flexible strip with the largest surface area to give it the proper bending according to the flow. According to an embodiment, the flexible strip comprises a silicone body. The strip could be formed of other flexible materials, including other plastics. In some embodiments the flexible strip could even be formed of a metallic material or a composite material. Forming of a silicone or plastic can provide for a resilient flexible strip that can be easily formed according to system requirements.

According to an embodiment, the flexible strip comprises a distal portion holding the magnet; a central portion; and a proximal portion connecting to the sensor element. Optionally, the distal portion is thicker than the central portion. Further optionally, the proximal portion is cylindrical and the sensor element fits at least partially within the proximal portion. Such a shape can ensure that the flexible strip is able to bend with the flow and thereby allow the sensor to determine flow rate and/or direction while also ensuring that it interferes with the flow to a minimal degree.

According to an embodiment, the flow sensor further comprises a mount connected to the flexible strip for mounting the flow meter with respect to the pipe. Optionally, the mount secures the strip to a cartridge which can move the flexible strip into and out of the pipe. Such a system allows for a compact package with the flow sensor and cartridge able to be assembled, for example, at a manufacturing site, and then easily positioned together to have the flexible strip at the desired position with respect to pipe.

According to an embodiment, the sensor further comprises a master node connected to a slave node which connects to the sensor element, the master node configured to perform one or more of the following: request a signal from the sensor element; store data related to signals from the sensor element; and push signals to another device. The slave node can be located near or at the flexible strip, for example in the cartridge. The master node and slave node could be connected with a wired connection or wirelessly.

According to an embodiment, the system further comprises a processor configured to: receive signals from the sensor element indicating a position of the magnet in the flexible sensor; and determine a flow rate and/or direction based on the signals received. Optionally, the processor is part of the slave node and/or master node. In some embodiments there could be a number of processors. Using a master node and a slave node with one or more processors in the system allows for the ability to collect measurements at different intervals, store measurements, and/or send such measurements to where they could be accessed by a user or other person associated with the system. This enables easy monitoring and viewing of data from the monitoring no matter the desired frequency of measurement intervals and reporting. Master node can request slave node to take a measurement at any desired interval, convert it to useable data, store such measurements and data, and report further at any desired interval. This could also enable other functions, such as alerts when measurements are outside of specific ranges. The use of master node, slave node and one or more processors allows for a versatile system of collecting measurements from the flow sensor, converting the measurements to flow data and reporting at desired intervals. According to a further aspect of the invention, a method of sensing flow comprises inserting a flexible element perpendicular to the direction of flow; sensing the position of a magnet located at a distal end of the flexible element when in the flow; and converting the sensed position of the magnet in the flexible element to a flow direction and/or rate. Such a method gives a reliable measurement of the flow direction and/or rate through a flow system even at flow rates which were previously difficult to measurement with past flow meters.

According to an embodiment, the method further comprises storing data related to the flow direction and/or rate. Optionally, the method further comprises sending data related to the flow direction and/or rate to a user. This allows for easy data measurements and reporting at any desired interval for each, allowing the system and method to be used with a variety of different flow systems.

According to an embodiment, the step of sending data related to the flow direction and/or rate to a user comprises sending data related to the flow direction and/or rate to a dashboard which is accessible to a user. Optionally, the step of sending data related to the flow direction and/or rate to a user comprises sending a package of data related to flow direction and/or rate at different times. The system and method allows for user reporting or user access to the data in a variety of forms, and thus is adaptable to different systems and user requirements.

Brief description of drawings

Embodiments will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts.

Figure 1 A shows perspective view of a flow sensor system in use in a pipe;

Figure 1 B shows an exploded view of the system of Fig. 1A;

Figure 2A shows a perspective view of a flexible strip;

Figure 2B shows a front view of the flexible strip of Fig. 2A;

Figure 2C shows a side view of the flexible strip of Fig. 2A;

Figure 3A shows a schematic depiction of a flow sensor system in a pipe with no flow;

Figure 3B shows a schematic depiction of the flow sensor system of Fig. 3A with flow through the pipe;

Figure 4 shows schematic depiction of the communication system of the flow sensor system;

Figure 5 shows a flow chart depicting the flow sensing system and communication.

The figures are meant for illustrative purposes only, and do not serve as restriction of the scope or the protection as laid down by the claims.

Detailed description

Further advantages, features and details of the present invention will be explained in the following description of some embodiments thereof. In the description, reference is made to the attached figures. Figure 1A shows perspective view of a flow sensor system 10 in use in a pipe 12, and Figure 1 B shows an exploded view of the system 10. Flow sensor system 10 includes flexible strip 14, slave node 16; master node 18 and mount 20. System 10 can be powered by a number of different sources, for example, battery-powered or connected to an electric grid, generator or other power source.

Mount 20 connects to flexible strip 14, and to cap 21 of cartridge 22 to secure flexible strip 14 at the proper position in pipe 12. Mount 20 includes a sealing connection to place flexible strip 14 at a lowered position within pipe for the flow sensor system 10 to be able to measure the flow rate and/or direction. Mount 20 can take a number of forms to secure the proximal portion of flexible strip 14 to an insertion point of the pipe 12, for example, a through fitting which can secure to cap 21 with a threaded or snap connection, a bracket with a nut, etc. Mout 20 can also include one or more sealing members to ensure that the liquid flowing through pipe 12 does not escape. Additionally, flexible strip 14 and/or mount 20 can have features to facilitate the mounting at a desired position or location, e.g., circumferential grooves, indentations or other features for gripping and/or sealing.

Slave node 16 connects to the flexible strip 14 and sits within cartridge 22. Slave node includes sensor elements, including magnetometer 23, and can include a printed circuit board (PCB) with a processing unit to convert magenetometer measurements into flow rate and/or direction signals. System 10 could also include other sensors, for example, a temperature sensor, electrical conductivity sensor, pH sensor, oxygen cholride sensor, pressure sensor, etc. which could be connected to cartridge 22 or other components.

Master node 18 connects to slave node 16. This can be through a wired connection (as shown) or wireless in some cases. Master node 18 includes a communication box 24, and antenna 26. Master node 18 can perform one or more of the following functions: pull sensor readings from slave node 16 at certain intervals, store data regarding sensor readings, and send sensor reading data through antenna 26 to other systems or devices, for example a cellular tower or cellular network. Slave node 16 and/or master node 18 can be powered by, for example, a battery though could have other power sources.

Flexible strip 14 is shown in detail in Figs. 2A-2C, and includes a perspective view (Fig.

2A), a front view (Fig. 2B) and a side view (Fig. 2C). Flexible strip 14 includes a proximal portion 30 with a slot 32 for receiving a sensor element; a distal portion 34 and a middle portion 36. As can be seen, strip 14 is generally Hong and flat in middle portion 36 and distal portion 34, with proximal portion 30 (and with transition portions between). Distal portion 34 is wider than flexible portion 36, and holds magnet 38. Magnet 38 is shown as a round magnet, though could be different shapes depending on system requirements.

Flexible strip 14 can be formed in a number of ways, including casting, injection moulding, printing, etc. Typically, flexible strip would be integrally formed as one piece, either formed around magnet 38 (and possibly around all or part of magneto sensor) or with a way to insert magnet such that it is secured in distal portion 34, such as through one of the ends or sides. Flexible strip 14 is formed of a flexible material, for example silicone. In other embodiments strip 14 could be made of metals, other plastics, and/or composite materials.

Dimensions shown are length of flexing portion LF 43 mm; width of face WF 20 mm; sensing length Ls 50 mm; total length 73 mm; width distal portion WD 6 mm; width of central portion Wc 2 mm. These are example dimensions only, and could, for example, be a flexible sensor suitable for a 1 10 mm diameter pipe. However, in various embodiments, including embodiments suitable for 1 10 mm diameter pipes, dimensions can vary depending on sensor and system requirements.

When in use, middle portion 36 and distal portion 34 are inside pipe 12, while proximal portion 32 is outside pipe. This is depicted in Figs. 1 A and 3A-3B, with Fig. 3A showing flexible strip 14 in pipe 12 with no flow; and Fig. 3B showing flexible strip 14 in pipe 12 with flow through the pipe 12.

Flexible strip 14 is generally inserted radially into pipe 12 and secured to an opening in pipe wall. Flexible strip 14 must extend a sufficient length across pipe 12 diameter to be able to sense flow. This length can vary in different systems, depending on pipe diameter, expected flow, etc., but can for example be 10-90% across pipe diameter, and would often be in the range of about 25% to 50% of the pipe diameter. Additionally, flexible strip 14 must extend beyond any vicous forces or turbulent flow propogating from the pipe inner wall, and into the laminar flow for better accuracy in measurements. The wide face of strip 14 is position perpendicular to the flow direction through pipe 12 to ensure flow exerts force on the surface of strip 14 and results in bending or flexing of strip 14. The exact placement would depend on a number of factors, including but not limited to the flow rate, pipe diameter, medium of flow, etc.

Fig. 3B depicts flexible strip 14 bending from forces of the flow through pipe 12 acting on the face of strip 14. As distal portion 34 of strip 14 moves from the position with no flow shown in Fig. 3A to the position with flow shown in Fig. 3B, magnetometer 23 is able to sense a change in the magnetic field due to the movement of magnet 38 in distal portion 34 of strip 14. The amount and direction of bending are related to the direction and flowrate of flow through pipe. The sensed change of the magnetic field, caused by movement of magnet 38 with bending of strip 14, is used to calculate values for the flow rate and the direction of flow.

Flow sensor system 10 with flexible strip 14 allows for a simple, yet accurate flow measurement even at low flow rates where some past flow meters have difficulty measuring. Flexible strip 14 acts as a simple mechanical portion of a flow meter, bending from forces of the fluid flowing against the face of strip 14, and sensing element 23 with slave node 16 can measure the change in position of magnet 38 to measure the bend, and convert it to digital data which can be stored and transmitted. In some cases, the conversion from data related to the change in magnetic field to values for flow rate and direction can take place at master node instead of slave node. The use of a simple flexible strip 14 with magnet 38 placed directly into the flow, and a simple sensor element 23 allows for a reliable and long-lasting flow sensor system 10 for measuring fluid flow. Connecting each of magnet 38 and magnetometer 23 to flexible strip 14 ensures that that the relative positions are known and a change in magnetic field due to flexing can be easily determined. Figure 4 shows a schematic depiction of the communication system of the flow sensor system 10, and includes slave node 16, master node 18 with communication box 24, network server 40 and application server 42. Fig. 5 shows a flow chart 50 with an example of flow sensing system 10 functioning and communication.

Master node 18 with communication box 24 drives the flow sensing system 10 at the flow sensor, first pulling signals from slave node 16 at set intervals (step 52). These can be pre-set, for example, four times per hour, and can be changed when needed or desired. Master node 18 sends the signal to slave node that it requires flow data at a set time. This can be sent in advance, with slave node 16 sensing the data at an indicated time, or master node 18 could only request the flow data at the time needed.

When slave node 16 receives this signal, it senses the bending of flexible strip 14 by magnetometer 23 sensing the change in the magnetic field from movement of magnet 38 caused by the bending of strip 14 and the direction of flow based on the direction of bending (step 54). Typically the change in magnetic field would require an initial measurement before flow through the pipe, but could be done without the initial measurement, for example, simply using past or sample data. This initial measurement can be done in a lab before installation to give flexible strip 14 an initial position indication of zero. From this, after installation, a sensed bend in one direction could be given a positive measurement indication, and the bending in the other direction could be given a negative measurement indication, with each having a measurement strength to indicate a rate of flow. For example, a low flow rate in a first direction would induce bending of flexible strip 14 in a first direction to a small degree. Slave node 16 could sense this and give it a value of +3 to indicate flow direction and strength. If there was later a stronger flow through the pipe in the opposite direction, slave node 16 may sense this and give it a value of -7 to indicate the direction of flow and the increased flow rate.

Slave node 16 uses this change or sensed value of magnetic field and converts it to a flow rate and/or direction (step 56). This conversion can be, for example, based on an equation relating the values sensed to a flow rate and/or use a data look up table which compares measured changes/bending with flow rates of specific flow for a certain type/size of pipe and fluid. These conversions will be associated with a number of factors, including the fluid flowing through, temperature, pipe size, etc.

This data pulled form slave node 16 can then be stored in master node 18 (step 58) until it is pushed through network 40 to application server 42 (step 60). This can be stored in a memory of the master node and/or communication box. How this data is bundled, and the frequency that this data is pushed to application server can also be pre-set and/or changed. For example, the master node 18 could store data for one day, and only push it to the network once per day as a set of 24 values for flow rate over a period of a particular day. In other embodiments, master node 18 would store hourly flow rate measurements, and only send a maximum and minimum value for that time period to the network. Many different combinations for pulling data, storing data and sending data could be performed by system depending on factors such as the particular flow system being monitored, flow system events, available data storage, etc. The communication between slave node 16 and master node 18 is typically hard wired, though can be wireless in some systems. The communication from master node 18 to network 40 is typically wireless, for example, sending data through radio signal facilitated by antenna 26. In some embodiments, this could be a wired connection as well.

Once the values are in the application server, they can be either pushed to a user, for example, via messaging or an application (step 62). Alternatively, they can be displayed from application server at a location where a user could come to view the values. For example, application server could put the values in a dashboard accessible via a website at which a user could view the data sent by the master node 18.

In some embodiments, flow sensing system 10 can send push alerts or warnings directly to a user when a value sensed is outside of a threshold value. This can enable an early warning system when values are outside of the expected normal range, allowing for earlier inspection and/or fixing of any system related problems. Threshold values can either be pre-set, or can be calculated depending on typical flow system expectations and/or measurements.

By using a simple flexible flow sensor, flow data related to flow rate and direction can be easily and reliably obtained in a flow system through a pipe. The use of a simple sensor with a magnet and magnetic sensing element results in a simple way to measure flow that is durable, which is particularly useful in systems measuring flow through underground pipes which are not easily accessible. Additionally, the placement and length of flow sensor, as well as the flexible materials used ensures that it can accurately measure flow even at low speed, which past systems had difficulty measuring accurately. The use of master node 18 and slave node 16 gives for a flexible system which can take measurements and bundle them for communication to others in a number of different ways. This can be especially useful in systems which vary wildly in flow throughout the year, only taking frequent measurements when necessary and communicating at intervals which make sense to the user.

The flow sensing system 10 can include one or more processors, special purpose computers, memories, hardware and/or software configured to perform one or more of the steps of Fig. 5, and/or configured to send signals prompting different parts of the system 10 to perform one or more actions for obtaining and displaying flow rate data.

It will be understood that, when an element (for example, a first element) is“(operatively or communicatively) coupled with/to” or“connected to” another element (for example, a second element), the element may be directly coupled with/to another element, and there may be an intervening element (for example, a third element) between the element and another element. To the contrary, it will be understood that, when an element (for example, a first element) is“directly coupled with/to” or“directly connected to” another element (for example, a second element), there is no intervening element (for example, a third element) between the element and another element. All connections intended for transmission of data may be physical connections (wires) however, alternatively they may be wireless and based on transmission of electromagnetic / light radiation. The processor(s) unit may be any suitable processing unit. Memory may comprise different types of sub-memories, like ROM (Read Only Memory) types of memory storing suitable program instructions and data to run the processing unit 9. Also, memory will comprise suitable RAM (Random Access Memory) types of memory for storing temporary data like the data received from slave node. Memory may also comprise cache type memory.

Network modules may comprise one or more of LTE (Long Term Evolution), Ethernet, WiFi,

Bluetooth, Powerline communication, Low Power Wide Area Network (e.g. Narrowband and Narrowban loT), loT (Internet of Things) and NFC (Near Field Communication) modules.

Energy can be provided by one or more batteries arranged to feed electrical energy to all other components needing energy via suitable wires (not shown). Alternatively, there may be a connection to the mains or other energy source, though that may be impracticable in many situations. The energy device may comprise a rechargeable battery and means to generate electrical energy to recharge the rechargeable battery, like a small solar panel, wind mill, fuel cell, etc.

The system can also include a clock to provide clock signals to processing unit. The clock signals can be used for the normal processing of processing unit, and for correlating times for requesting and sending data, time stamping data, etc.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. It will be apparent to the person skilled in the art that alternative and equivalent embodiments of the invention can be conceived and reduced to practice. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

1. A flow sensor comprising:

a flexible strip for insertion into a flow in a flow system;

a magnet located at a distal end of the flexible strip; and

a sensor element connected to the proximal end of the flexible strip for sensing a bend of the flexible strip.

2. The flow sensor of claim 1 , wherein the sensor element comprises a magnetometer.

3. The flow sensor of claim 2, wherein the magnetometer measures the change in magnetic field due to the movement of the magnet; and the measured data is converted to a flow direction and/or rate.

4. The flow sensor of any of the preceding claims, wherein the flow system is a pipe and the flexible strip is inserted into the pipe perpendicularly to the direction of flow through the pipe.

5. The flow sensor of any of the preceding claims, where the flexible strip comprises a silicone body.

6. The flow sensor of any of the preceding claims, wherein the flexible strip comprises

a distal portion holding the magnet;

a central portion; and

a proximal portion connecting to the sensor element.

7. The flow sensor of claim 6, wherein the distal portion is thicker than the central portion.

8. The flow sensor of any of claims 6-7, wherein the proximal portion is cylindrical and the sensor element fits at least partially within the proximal portion.

9. The flow sensor of any of the preceding claims, and further comprising:

a mount connected to the flexible strip for mounting the flow meter with respect to the pipe.

10. The flow sensor of claim 9, wherein the mount secures the strip to a cartridge which can move the flexible strip into and out of the pipe.

1 1 . The flow sensor of any of the preceding claims, and further comprising:

a master node connected to a slave node which connects to the sensor element, the master node configured to perform one or more of the following: request a signal from the sensor element; store data related to signals from the sensor element; and push signals to another device.

12. A flow sensing system comprising the flow sensor of claim 1 1 , and further comprising: a processor configured to:

receive signals from the sensor element indicating a position of the magnet in the flexible sensor; and

determine a flow rate and/or direction based on the signals received.

13. The flow sensing system of claim 12, wherein the processor is part of the slave node.

14. A Method of sensing flow comprising:

- inserting a flexible element perpendicular to the direction of flow;

- sensing the position of a magnet located at a distal end of the flexible element when in the flow; and

- converting the sensed position of the magnet in the flexible element to a flow direction and/or rate.

15. The method of claim 14, and further comprising:

- storing data related to the flow direction and/or rate.

16. The method of claim 15, and further comprising:

- sending data related to the flow direction and/or rate to a user.

17. The method of claim 16, wherein the step of sending data related to the flow direction and/or rate to a user comprises sending data related to the flow direction and/or rate to a dashboard which is accessible to a user.

18. The method of any of claims 16-17, wherein the step of sending data related to the flow direction and/or rate to a user comprises sending a package of data related to flow direction and/or rate at different times.