Extensible sensor for filter bags

Abstract

A filter bag sensor system including an extensible sensor system disposed on a filter bag and wherein the extensible sensor system provides a signal indicative of a deformation of a filter bag.

Description

EXTENSIBLE SENSOR FOR FILTER BAGSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application, under 35 U.S.C. § 119, claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 595,627 filed on November 02, 2024, and entitled “Extensible Sensor For Filter Bags,” the contents of which are hereby incorporated by reference herein.FIELD OF THE DISCLOSURE

[0002] This disclosure relates generally to compliant sensor systems and methods for sensors that bend, flex, stretch, twist, or the like to measure, force, strain, stress, or the like. More particularly, this disclosure relates to extensible sensor systems and methods for sensors configured to detect wear-and-tear on filtration bags and the like.BACKGROUND

[0003] Flexible sensors are known. For example, U.S. Pat. Nos.: 8,941,392; 9,222,764; 9,476,692; 9,612,102; 9,874,431; 10,551,917; 10,823,546; 10,959,644, and U.S. Pat. App. Pub. 2022 / 0034692, the contents of which are hereby incorporated by reference herein, disclose flexible sensors.

[0004] Air filtration systems are also known. Typically, air is circulated with fans or impellers to move air and any particulate matter through a filter to remove the particulate matter. In some industrial settings (e.g., lumber mills, manufacturing facilities, and the like) the filter may comprise a bag type filter that may be held in place over a cage or similar structure. As particulate matter builds up on the outside of the filter bag it is often desirable to reverse airflow, or use a burst of increased airflow, to shake the particulate matter off the filter bag for collection and removal. Over time and with use the filter or filter bags may abrade, tear, or otherwise wear out. Current systems do not provide a way to monitor wear-and-tear other than by visual inspection which can be imperfect, time-consuming, and inconvenient.

[0005] Likewise, in some environments (e.g., high humidity environments), high-moisture particulate matter may not be knocked off the filter by a pulse or reverse airflow. Again, current systems do not provide an indication of failed removal other than by visual inspection which can be imperfect, time-consuming, and inconvenient.

[0006] In some environments and uses, knocking off too much particulate matter at one time can also be detrimental to collection and removal and other down-line equipment. Other drawbacks, inconveniences, inefficiencies, and issues also exist with current systems and methods.SUMMARY

[0007] Accordingly, disclosed embodiments address the above, and other, drawbacks, inconveniences, inefficiencies, and issues that exist with current systems and methods. Other advantages and efficiencies of disclosed systems and methods also exist.

[0008] As used herein, “flexible,” “extensible,” “compliant,” “deformable,” and the like are used somewhat interchangeably and all mean that some amount of flexing, stretching, compression, twisting, bending, or the like, exists for the described embodiment.

[0009] It should be understood that, as used herein, the terms “vertical,” “horizontal,” “lateral,” “upper,” “lower,” “top,” “bottom,” “left,” “right,” “inner,” “outer,” etc., can refer to relative directions or positions of features in the disclosed devices and / or assemblies shown in the Figures. For example, “upper” or “uppermost” can refer to a feature positioned closer to the top of a page than another feature. These terms, however, should be construed broadly to include devices and / or assemblies having other orientations, such as inverted or inclined orientations where top / bottom, over / under, above / below, up / down, and left / right can be interchanged depending on the orientation.

[0010] Disclosed exemplary embodiments include an extensible capacitive sensor that may be mounted on an interior or exterior surface of a filter, or mounted on a filter support structure, and that is capable of detecting bending, stretching, and other deformations which can be used to determine if the filter material has degraded due to thermal degradation, mechanical degradation, chemical attack, or the like. In some embodiments output from the extensible capacitive sensor may be used to optimize pulsing strategies and maintenance cycles for filters.In other embodiments the extensible capacitive sensors may detect and track micro-tearing and abrasion of the fdter bag over time. In some embodiments extensible capacitive sensors may be used for detection of high moisture-content dust and particulate matter that fails to be knocked off the filter. In some embodiments the extensible capacitive sensors may be used to detect and prevent too much material being collected and knocked off at once, potentially causing material flow issues for the hopper below. Other embodiments also exist.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 is a schematic cross-sectional view of a stack of layers to form a compliant sensor system in accordance with disclosed embodiments.

[0012] FIG. 2 is a multi-region angular displacement sensor in accordance with disclosed embodiments.

[0013] FIG. 3 is a schematic example of an extensible printed flexible capacitive sensor system in accordance with disclosed embodiments.

[0014] FIG. 4 is a schematic illustration of typical prior art baghouse filtration systems.

[0015] FIG. 5 is an exemplary illustration of an extensible capacitive sensor system mounted on a filter bag in accordance with disclosed embodiments.

[0016] FIGS. 6A and 6B are schematic cross-sectional illustrations of filter bag under normal filtering and normal pulse cleaning operation in accordance with disclosed embodiments.

[0017] FIGS. 7A and 7B are schematic cross-sectional illustrations of exemplary sensor locations in accordance with disclosed embodiments.

[0018] FIGS. 8A-8D are schematic side view illustrations of exemplary sensor locations in accordance with disclosed embodiments.

[0019] While the disclosure is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the appended claims.DETAILED DESCRIPTION

[0020] FIG. 1 is a schematic cross-sectional view of a stack of layers to form a compliant sensor system 200. As shown, dielectric layer 12, is in between top electrode layer 2 and signal electrode layer 16. As also indicated schematically, perimeter electrode 140 electrically connects top electrode layer 2 and signal electrode layer 16. Other configurations are also possible.

[0021] In some embodiments, top electrode layer 2 may comprise an elastomeric layer (e.g., silicone) with conductive particles (e.g., nano-particles, such as carbon black, nickel nanostrands, silver nano-particles, graphene nano-platelets, graphene-oxides, or the like) integrated within. While shown in FIG. 2 as a continuous layer, top electrode layer 2 may also be “hatched” or otherwise non-continuous. Top electrode layer 2 may also include a printed circuit board (PCB) interface and a number of conductive trace pads for attaching a PCB, sensor traces, or other electronics, for operation and control of the sensor system.

[0022] In some embodiments dielectric layer 12 may comprise an elastomeric material (e.g., silicone) and, as desired, may have some conductive material integrated within depending upon, among other things, the intended amount of permittivity, or the like. While not drawn rigorously to scale in FIG. 1, in some embodiments dielectric layer 12 is sized to be slightly smaller than top electrode layer 2 to leave a perimeter edge of top electrode layer 2 uncovered by dielectric layer 12 and allow electrical contact with perimeter electrode 140 as disclosed below.

[0023] In some embodiments signal electrode layer 16 may comprise an elastomeric material (e g., silicone) with conductive material (e.g., nano-particles, such as carbon black, nickel nano-strands, silver nano-particles, graphene nano-platelets, graphene-oxides, or the like) confined to sensor regions, traces, and perimeter electrode 140. A number of sensor regions 20 (labeled as “sensing region” in FIG. 3 and used herein interchangeably with “sensor region”) may be distributed throughout the layer 116 (see, e.g., FIG. 3). Sensor regions 20 may comprise regions of electrically conductive material. Sensor regions 20 are electrically in communication with traces 22 (labeled as “signal trace line” in FIG. 3 and used herein interchangeably with “trace” and “traces”) that are printed with signal electrode layer 16. As shown, embodiments of signal electrode layer 16 may include a perimeter electrode 140 thatelectrically connects to top electrode layer 2 to, among other things, provide electrical isolation for the entire sensor system. Other configurations are also possible.

[0024] FIG. 2 is a multi-region angular displacement sensor 800 in accordance with disclosed embodiments. As shown, embodiments of the sensor system 200 as disclosed in FIG. 1, may be coupled together to form an angular displacement sensor 800. For example, by coupling sensor system 200A through an elastomeric connector 802 to a second sensor system 200B an angular displacement sensor 800 (single region, multi-region, or the like) may be implemented. Additional disclosure of the construction, operation, and implementation of such displacement sensor systems 800 may be found in U.S. Pat. No. 10,551,917, titled “Compliant Multi -Region Angular Displacement And Strain Sensors,” and the disclosure of which is hereby incorporated by reference in its entirety.

[0025] As persons of ordinary skill in the art having the benefit of this disclosure would understand, the angular displacement sensor 800 can be extended to as many regions as desired as indicated by additional elastomeric connectors 802 and sensor system 200N. Other configurations are also possible.

[0026] FIG. 3 is a schematic example of an extensible printed flexible capacitive sensor system 300 in accordance with disclosed embodiments. As shown, at least one sensing region 20 may be included in an elastomeric material and provided with one or more signal traces 22 for electronic communication with other system circuitry and components. Other configurations are possible.

[0027] FIG. 4 is a schematic illustration of typical prior art pulse-jet baghouse filtration systems 400. As indicated schematically on the left side of FIG. 4 (“Normal Operation”) one or more filter bags 402 may be held in place over a wire cage 404 (portion of filter bag 402 removed for visibility of wire cage 404). Airflow 406, as indicated by the largest arrows, is moved or flowed through the filter bag 402 and into a manifold or tubesheet 408 for recirculation as desired. A fan or impeller (not shown) is used to control airflow 406. Particulate matter 410 (e.g., dust, sawdust, and the like) present in the airflow 406 is deposited on the outside of the filter bag 402. Other configurations are possible, such as having airflow 406 be pulled through the inside of the filter bag 402 so that particulate matter 410 is trapped within the filter bag 402.

[0028] As also shown on the right side of FIG. 4 (“Pulse Cleaning”) in some embodiments it is desirable to reverse airflow 406R as a cleaning air pulse through the filter bags 402 and remove particulate matter 410 from the surface of the filter bag 402. Other configurations and cleaning methods such as reverse airflow that reverses airflow through the filter bag but without using a pulse-jet and shaker cleaning that shakes the filter bags to remove dust are also possible and the herein disclosed sensor systems and methods are equally applicable to any system and method for cleaning.

[0029] FIG. 5 is an exemplary illustration of an extensible capacitive sensor system 200 mounted on a filter bag 402 in accordance with disclosed embodiments. As illustrated extensible capacitive sensor system 200 may be mounted to an outer surface of filter bag 402 along with associated control, monitoring, and power circuits 202. In some embodiments extensible capacitive sensor system 200 may be mounted to an inner surface of filter bag 402 or multiple extensible capacitive sensor systems 200 may be mounted on inner and outer surfaces of filter bag 402. As will be apparent to those of ordinary skill in the art having the benefit of this disclosure, the extensible capacitive sensor system 200 may be used to monitor the degree (amount and direction) of strain, the number of times a filter bag 402 is flexed (or pulsed) clean, failure conditions (e.g., tears, holes, etc.), reduced flexing due to particulate matter, and the like. As will also be apparent to those of ordinary skill in the art having the benefit of this disclosure, the extensible capacitive sensor system 200 and the use of the disclosed elastomeric materials for the same enable applications with large strains with fully elastic recovery and are resistant to chemicals, impact, vibration, and fatigue. The disclosed extensible capacitive sensor systems 200 also provide a high degree of design flexibility enabling application-specific design, powering, data sampling rate, data communication, and the like, and allowing for highly customizable sensitivity and positioning for each sensing region. Furthermore, the herein disclosed extensible capacitive sensor system 200 has low power consumption using power in the microampere range depending upon on sampling rate and voltage powering the circuit. Other advantages also exist.

[0030] FIGS. 6 A and 6B are schematic cross-sectional illustrations of filter bag 402 under normal filtering and normal pulse cleaning operation in accordance with disclosed embodiments. As illustrated in FIG. 6A (and similarly in FIG. 4 left side), filter bag 402 is supported on, and often rubs against, wire support frame 404 due to the inwards airflow 406which can cause wear. Particulate matter (not shown in this illustration) collects on the outer surface of filter bag 402. As shown in FIG. 6B (and similarly in FIG. 4 right side) during normal pulse cleaning airflow is reversed (as shown in airflow 406R) and filter bag 402 expands and experiences an outward strain to knock particulate matter off the outer surface and which can also lead to wear and tear.

[0031] FIGS. 7A and 7B are schematic illustrations of exemplary sensor 200 locations in accordance with disclosed embodiments. As shown in FIG. 7A an extensible capacitive sensor system 200 may be centered on one of the wires of wire cage 404. In other embodiments as shown in FIG. 7B an extensible capacitive sensor system 200 may be centered between two wires of the wire cage 404. Either sensor 200 orientation as shown in FIGS. 7A-7B take advantage of a pivot point and allow maximum sensor 200 deformation and associated signal. As will be apparent to those of ordinary skill in the art having the benefit of this disclosure, other orientations and locations are also possible for the sensor system 200 such as wrapping around substantially the entire circumference of filter bag 402 (inner or outer surface) or being positioned along a length of the filter bag 402.

[0032] FIGS. 8A-8D are schematic side view illustrations of exemplary sensor 200A-F locations in accordance with disclosed embodiments. As indicated schematically in FIGS. 8A- 8B sensors 200A, 200B, 200C may be placed longitudinally (i.e., “lengthwise”) along filter bag 402 at one or more locations and of varying length. As indicated in FIG. 8C sensors 200D may also be oriented “diagonally” or in more than one direction as shown at 200E to measure in multiple directions. As also indicated in FIG. 8D sensor 200F may be located inside filter bag 402 either on an inner surface of the filter bag 402 or on the wire frame 404. As those of ordinary skill in the art having the benefit of this disclosure will also understand, combinations of the various orientations and locations may also be used. Further, multi-modal sensors 200 (e g., those that measure more than one parameter such as strain, pressure, angular displacement, and the like) may also be implemented in accordance with this disclosure.

[0033] Although various embodiments have been shown and described, the present disclosure is not so limited and will be understood to include all such modifications and variations would be apparent to one skilled in the art.

[0034] Exemplary embodiments include:1. A filter bag sensor system having:an extensible sensor system disposed on a filter bag and wherein the extensible sensor system provides a signal indicative of a deformation of a filter bag. The filter bag sensor system of exemplary embodiment 1 wherein the extensible sensor system further includes a capacitive sensor. The filter bag sensor system of exemplary embodiment 1 further including: a support structure for holding the filter bag in a predetermined orientation; and wherein the extensible sensor system is disposed on a pivot point of the support structure. The filter bag sensor system of exemplary embodiment 1 further including: a support structure for holding the filter bag in a predetermined orientation; and wherein the extensible sensor system is disposed between substantially rigid members of the support structure. The filter bag sensor system of exemplary embodiment 1 wherein the extensible sensor system is configured to be disposed on a pivot point of a support structure used to hold the filter bag in a predetermined position. The filter bag sensor system of exemplary embodiment 1 wherein the extensible sensor system is configured to be disposed between substantially rigid members of a support structure used to hold the filter bag in a predetermined position. The filter bag sensor system of exemplary embodiment 1 wherein the extensible sensor system is positioned substantially longitudinally along a length of the filter bag. The filter bag sensor system of exemplary embodiment 1 wherein the extensible sensor system is positioned substantially diagonally across the filter bag.The filter bag sensor system of exemplary embodiment 1 wherein the extensible sensor system is positioned substantially circumferentially around the filter bag. The filter bag sensor system of exemplary embodiment 1 wherein the extensible sensor system is positioned in at least two different directions along the filter bag The filter bag sensor system of exemplary embodiment 1 wherein the extensible sensor system further comprises a multi-modal sensor system. The filter bag sensor system of exemplary embodiment 1 wherein the extensible sensor system is positioned on an inner surface of the filter bag. The filter bag sensor system of exemplary embodiment 1 wherein the extensible sensor system is positioned on an outer surface of the filter bag.

Claims

WHAT IS CLAIMED IS:

1. A filter bag sensor system comprising: an extensible sensor system disposed on a filter bag and wherein the extensible sensor system provides a signal indicative of a deformation of a filter bag.

2. The filter bag sensor system of claim 1 wherein the extensible sensor system further comprises a capacitive sensor.

3. The filter bag sensor system of claim 1 further comprising: a support structure for holding the filter bag in a predetermined orientation; and wherein the extensible sensor system is disposed on a pivot point of the support structure.

4. The filter bag sensor system of claim 1 further comprising: a support structure for holding the filter bag in a predetermined orientation; and wherein the extensible sensor system is disposed between substantially rigid members of the support structure.

5. The filter bag sensor system of claim 1 wherein the extensible sensor system is configured to be disposed on a pivot point of a support structure used to hold the filter bag in a predetermined position.

6. The filter bag sensor system of claim 1 wherein the extensible sensor system is configured to be disposed between substantially rigid members of a support structure used to hold the filter bag in a predetermined position.

7. The filter bag sensor system of claim 1 wherein the extensible sensor system is positioned substantially longitudinally along a length of the filter bag.

8. The filter bag sensor system of claim 1 wherein the extensible sensor system is positioned substantially diagonally across the filter bag.

9. The filter bag sensor system of claim 1 wherein the extensible sensor system is positioned substantially circumferentially around the filter bag.

10. The filter bag sensor system of claim 1 wherein the extensible sensor system is positioned in at least two different directions along the filter bag.

11. The filter bag sensor system of claim 1 wherein the extensible sensor system further comprises a multi-modal sensor system.

12. The filter bag sensor system of claim 1 wherein the extensible sensor system is positioned on an inner surface of the filter bag.

13. The filter bag sensor system of claim 1 wherein the extensible sensor system is positioned on an outer surface of the filter bag.

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