External-Mounted Strain Sensor System for Non-Invasive Measurement of Internal Static and Dynamic Pressures in Elastic Bodies
20220364944 · 2022-11-17
Inventors
Cpc classification
G01L17/005
PHYSICS
G01L1/2218
PHYSICS
International classification
G01L17/00
PHYSICS
G01L1/20
PHYSICS
Abstract
A sensor system comprises flexible piezoelectric polyvinylidene fluoride wire/strip and/or a short/extended strain gauge wire/printed strain gauge transducers to measure both static and dynamic pressure, conditioning electronics, installation/adherence tool, calibration tool, electronic devices for measuring pressure outputs, and wireless transmission of sensor signal through a data acquisition system to a smart device. A software application for reading the output of the strain gauges remotely is included. Individual system components include distributed strain sensors, custom printed strain gauges, strain gauge wires, calibration rig, slotted ring clamp, strain measuring devices, and software application for visualization of pressure readings.
Claims
1. A distributed strain sensor (100)/(400) system (12) for measuring strain over a significant dimension fraction length or area of a surface of an elastic pressure vessel (r), the distributed strain sensor (100)/(400) system (12) comprising: a strain sensor (100)/(400), or multiple strain sensors (100)/(400), each having continuous, segmented flexible or nonflexible piezoelectric material (PVDF); or a strain sensor (100)/(400), or multiple strain sensors (100)/(400), each having continuous, segmented flexible or nonflexible strain gauge material; and wherein each strain sensor (100)/(400) is composed of a flat ribbon (401), cylindrical wire (101) or combinations thereof.
2. The distributed strain sensor (100)/(400) system (12) of claim 1, wherein: each strain sensor (100)/(400) is attached to the exterior of the elastic pressure vessel (r); or clamped to the exterior of the elastic pressure vessel (r) by a clamp (200).
3. The distributed strain sensor (100)/(400) system (12) of claim 1, wherein: each strain sensor (100)/(400) is attached to the surface of the elastic pressure vessel (r), and is either glued or fixed with adhesive tape; or each strain sensor (100)/(400) is wrapped a complete or partial number of turns around the elastic pressure vessel (r); or combinations thereof.
4. The distributed strain sensor (100)/(400) system (12) of claim 1, wherein: each strain sensor (100)/(400) is combined with multiple strain sensors (100)/(400) forming an array or multiple arrays of individual strain sensors (100)/(400) arranged axially, tangentially, or at an angle along a dimension of the surface of the elastic pressure vessel (r).
5. The distributed strain sensor (100)/(400) system (12) of claim 1, wherein: each strain sensor (100)/(400) further has EMF shielding (102), and/or electronic connections and circuitry to implement the EMF and electrical noise shielding at (600).
6. The distributed strain sensor (100)/(400) system (12) of claim 1, further comprising: electronics (601) to convert the piezoelectric charge output into amplified proportional voltage; or electronics (601) to convert each sensor strain output into proportional voltage; or combinations thereof.
7. The distributed strain sensor (100)/(400) system (12) of claim 1, further comprising: a clamp (200) to accommodate each sensor (100)/(400) or an array of clamps (200) to accommodate each sensor (100)/(400) in an array of multiple sensors (100)/(400); wherein each clamp (200) holds each sensor (100)/(400) against the surface of the elastic pressure vessel (r), includes sensor electronics (601), is made from stiff materials, has four segments (201), (202), (203) and (205), or is spring loaded at (300) to create different diameters to accommodate differences dimensions along the surface of the elastic pressure vessel (r), or combinations thereof.
8. The distributed strain sensor (100)/(400) system (12) of claim 7, wherein: the PVDF wire/strip (101) is disposed on the clamp (200) to facilitate contact with the surface of the elastic pressure vessel (r); the PVDF wire/strip (101) is fed through, and disposed within, a threaded groove (211) or a groove (211) designed to accommodate the PVDF wire/strip (101).
9. The distributed strain sensor (100)/(400) system (12) of claim 1, further comprising: a calibration rig (500) for calibrating each sensor (100)/(400) either individually or as an array of sensors (100)/(400), the calibration rig (500) having a surface of an elastic pressure vessel (r) with known pressures differences.
10. The distributed strain sensor (100)/(400) system (12) of claim 1, further comprising: software to convert each sensor output voltage into pressure units; or multiple sensor output into flow rate; or multiple sensor output into fault detection of leaks, pump failure and valve failure; or each sensor or multiple sensor output into corrosion detection; or multiple sensor outputs into slug flow detection and measurement of acoustic wave speed and pipe wall thickness; or combinations thereof; and artificial intelligence combined with machine learning for predictive modeling and detection of pipe failure modes including over pressure, under pressure, fault detection of leaks, pump failure, valve failure, corrosion buildup, or combinations thereof.
11. A clamp (200) for clamping a distributed sensor (100)/(400) to a surface of an elastic pressure vessel (r), comprising: sensor (100)/(400) clamp (200) for clamping the distributed sensor (100)/(104) to an elastic pressure vessel (r), which completely encircles the pressure vessel (r), and maintains pressure on the distributed sensor (100)/(400) to clamp it to the elastic pressure vessel (r).
12. The clamp (200) for clamping a distributed sensor (100)/(400) to the elastic pressure vessel (r) of claim 11, further comprising: a spring and latch at (300) to apply pressure to the sensor (100)/(400).
13. The clamp (200) for clamping a distributed sensor (100)/(400) to the elastic pressure vessel (r) of claim 11, further comprising: a feed hole (213) and groove (211) for locating the sensor (100)/(400).
14. The clamp (200) for clamping a distributed sensor (100)/(400) to the elastic pressure vessel (r) of claim 11, further comprising: a connection terminal at (301), power electronics (600), and a voltage output terminal at (301) for the sensor (100)/(400).
15. The clamp (200) for clamping a distributed sensor (100)/(400) to the elastic pressure vessel (r) of claim 11, wherein: the clamp (200) is constructed from polymer, metals, or composite material; or the clamp (200) is constructed by 3D printing; or combinations thereof.
16. The clamp (200) for clamping a distributed sensor (100)/(400) to the elastic pressure vessel (r) of claim 11, comprising: battery power, lines main power or solar power of the sensor (100)/(400) electronics (600); a wireless system to transmit the sensor signal for storage and data processing in the cloud; or combinations thereof.
17. A calibration rig (500), comprising: an elastic pressurized tube (r) for calibrating a distributed sensor (100)/(400) or a plurality of distributed sensors (100)/(400).
18. The calibration rig (500) of claim 17, further comprising: an internal pressure exciter to provide static and dynamic pressure.
19. The calibration rig (500) of claim 17, further comprising: one or more standard pressure sensors to provide a reference pressure value.
20. The calibration rig (500) of claim 17, further comprising: tubing (505) connected to a pump (P) to provide static and dynamic pressure.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The novel features of the described embodiments are specifically set forth in the appended claims; however, example embodiments relating to the structure of the present invention, may best be understood with reference to the following description and accompanying drawings.
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[0038] Similar reference characters denote corresponding features consistently throughout the attached drawings.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0039] The present invention is drawn to an externally mounted strain sensor (100)/(400) system (12) and to an array of sensors (100)/(400) composed of a plurality of individual strain sensor (100)/(400) systems (12). This system (12) is based on a flexible piezoelectric polyvinylidene fluoride (PVDF) wire (101) or strip transducer and includes a printed strain gage transducer (401) or a resistor wire (101)/(401) wrapped around a container with elastic pressure vessel (r) walls to measure internal fluid borne acoustic signatures.
[0040] The system (12) includes two sensor types (100)/(400), controlling electronics (600), installation/adherence tool (200), calibration rig (500), measuring devices, wireless transmission of sensor signal through a data acquisition system, and software application for smart phones and or tablets for visualization of recorded data to produce either a static or dynamic output depending on the type of transducer used. Software for processing the sensor(s) output to measure dynamic pressure, static pressure, flow rate, corrosion of elastic body, bubbles in the fluid, slug flow, pump and bearing faults, and in homogeneity of the fluid is also included. The specific system components include a PVDF distributed strain sensor (100)/(400) (100) transducer, custom printed strain gauge transducer, calibration rig (500), slotted ring clamp (200) for PVDF sensor, PVDF sensor power/conditioning (600), sensor output recording module, software for processing the strain signals, and a software application for visualization of measurements recorded from the sensors. The term “each” as used herein shall refer to every one of one or more sensors, and not just every one of two or more sensors as the term is conventionally defined.
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[0043] A hole (213) is included in the fourth clamp part (205) to feed the PVDF wire (101) into the clamp (200). A cover (210) is put in place over the sensor termination/electronics compartment (207) on the fourth clamp part (205) for sealing the compartment after sensor wire (101) installation in the clamp (200). The clamp parts (201), (202), (203) and (205) include helical grooves (211) which, when all four parts (201), (202), (203) and (205) of the clamp (200) are assembled, serve as a continuous groove (211) for PVDF wire (101) installation in a self-winding manner as the wire (101) is fed into the installation access hole (213).
[0044] Fastening of the clamp (200) to a pipe is achieved using a spring-loaded screw or latch which is placed through the corresponding screw hole (204) on the third part of the clamp (203) and screw hole (206) of the fourth part (205) of the clamp (200). All four parts of the clamp (201), (202), (203) and (205) are grooved (211) in a helical manner to facilitate the self-winding function of the clamp (200). In addition to the use of the spring-loaded screw/latch or the like for fastening, the clamp parts (201), (202), (203) and (205) are fastened together using pins at hinge points (212) located on each part of the clamp parts (201), (202), (203) and (205).
[0045] Installation of the wire sensors (101) is achieved through pushing the triaxial cable end of the sensor into the self-winding clamp (200) via the feed hole (213) on the fourth main clamp part (205) at compartment (207). The self-winding around the pipe (or other element being measured) is achieved through the grooves (211) in the assembled clamp (200) that serve as threads for the wire (101) to be wound through until completely wound in the clamp (200). These concentric grooves (211) prohibit the wire (101) from winding over itself and ensure complete turns of the wire occur. Upon successful feeding of the wire (101) fully into the clamp (200) from feed end and through the internal groove (211), the wire (101) feeds out the opposite side of the third clamp part (203) part via an exit port (209) on the third part of the clamp (203). Through the consistent tension of clamp (200) installation and self-winding of the sensor (100), consistent installation is achieved and linear stress (stretching) of the sensor (100) is avoided. Avoidance of linear stress ensures consistent sensor readings. Other variations of the clamp (200) have grooves (211) so that partial turns of the PVDF wire (101) can occur.
[0046] Termination of the PVDF wire/strip (101) sensor (100) at the vessel/pipe (r) being measured is achieved using a threaded compression nut at (300) that attaches to connector (301) such as an MCX connector (301) or a latch located in the sensor access compartment/termination box at (208) on the clamp (200). The compression nut is tightened at the end of threading the sensor (100) into the self-winding clamp (200). The end opposite of the termination end of the PVDF sensor (100) end is connected via an MCX connector (301) to the systems conditioning/power module (600). The distributed strain sensor (100)/(400) (100) is utilized to achieve dynamic pressure output.
[0047] Commodity coaxial cable ends are utilized for integration into the clamp (200). A connector (301), such as an “MCX-style” connector (301), is used as the interconnect between the sensor wire (101) and the triaxial cable. While there is potential for unshielded cable length with this configuration, the length is to be kept as short as possible, and only be exposed from within the termination box (301) of the design clamps (200).
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[0049] The calibration rig (500) part of the system is utilized to calibrate and ensure correct resistance and accuracy of printed strain gauges (400) and distributed strain sensors (100)/(400) (100). An embodiment of the calibration rig (500) is illustrated in
[0050] The Wheatstone bridge/amplifier to monitor the string gauge(s) and a hydrophone are both attached to the calibration rig (500) for monitoring any installed sensor(s) (100) or (400). To determine system sensitivity, a wire sensor (100) is applied to the calibration rig (500) and subjected to standard excitation pressure signal. The output is then compared to the established reference values for the calibration rig (500) and the difference is used to determine the specific sensor's sensitivity.
[0051] The miniaturized circuit board (601) for the sensor power/conditioning module (600) provides signal conditioning for four separate PVDF sensors (100) and is a miniaturized signal conditioning pre-amplifier.
[0052] The smallest enclosure case (605) for a single channel is approximately 3″×3″×2″, contained in a weatherproof ruggedized die-cast aluminum case (607). A rubber seal (606), where the lid (608), shown in
[0053] For the electronics and sensor packaging, a single-channel fixed gain design has been created. The gain can be changed but is not intended to be a field adjustable value. Rather, the nominal gain tables derived during design will be used to provide a calibrated output. The circuit board, circuits, power supply, and connecters are installed in a metal box that is in line with the triaxial lead coming from the sensor wire/strip (101). The sensor wire/strip (101) is terminated in a standard BNC connector. An indicator light shows when the unit is powered on, and the battery pack is easily accessible through removal of four Philips head screws (607) for example which are located on the top of the case (605). The complete system (12) can be calibrated with the calibration rig (500).
[0054] Nominal sensitivity of PVDF sensors (100) on standard schedule 40 Steel pipe sizes, based on number of turns of the sensor wire (101) around the pipe (r) using the clamp (200) as an installation tool, are represented in
[0055] A mobile/tablet software application is also presented for visualization of data captured by either the Wheatstone Bridge/Amplifier for the printed strain gauge (400), or strain gauge wire (102), or the sensor power/conditioning module (600) for PVDF sensors (100) and (400). The application includes both a cloud-based server component as well as a client application for end user use.
[0056] An example of the server side has an application which operates on cloud service and interfaces with any client with internet connectivity for access to exposed RESTful services including sensors (100)/(400), mobile, and web applications. The client application as an example operates on both Android® and Apple iOS® operating systems and is also supported via web browsers including, but not limited to, Internet Explorer®, Mozilla Firefox®, and Google Chrome®. Clients access a cloud provider where measured and captured pressure data is stored. Users are authenticated with JSON web tokens for example. An overview of this architecture is represented in
[0057] Pressure measurements taken by the sensors (100)/(400) are captured by the power/conditioning module (600) for PVDF sensors (100) or via the Wheatstone Bridge/Amplifier for printed strain gauges (400). The data measurements are then passed to a commercially available “miniaturized computer” such as for example a Raspberry Pi with Wi-Fi and/or cellular service functionality which serves as a wireless data transmission device. This sending unit is either directly connected or integrated to the power/conditioning module (600), or physically connected to the Wheatstone Bridge/Amplifier.
[0058] Using either the Wi-Fi or cellular connectivity, the Raspberry Pi uploads the pressure measurement data captured to the cloud provider via REST API with an authenticated JSON web token. The data is analyzed using quantitative predictive modeling techniques, and processed with full visualization support including performance summaries, time-histories, alerts, and notifications across all mobile device platforms. When an array of sensors (that is more than one sensor (100) axially located on the elastic body) are used, the signals from the individual sensor (100) in the array are acquired, sent to the cloud or a local processor in which software is implemented to process the individual signals to also measure flow rate, corrosion of the elastic containing body, bubbles in the fluid and inhomogeneity of the fluid.
[0059] The cloud service for pressure data storage includes a database, Apache CXF service framework, and a Jetty HTTP server visually supported by
[0060] The client application is launched by the user on the device they are using to retrieve sensor data. The user then authenticates to the cloud server as a unique and authorized user using a unique user identification (ID) and password combination. Once connected, the user selects the option of Advertise on the application home screen which can be seen in
[0061] An example application of the PVDF sensor (702) can be seen in
[0062] Another example involves the use of an array of sensors (100) and/or (400) to non-invasively monitor the health of pipelines.
[0063] It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.