Durable sensor for detecting organic liquids

Abstract

An organic liquid sensor is provided that is configured to output a signal corresponding to the presence of one or more organic liquids. The sensor includes a circuit board, a sensor film deposited on the circuit board, the sensor film including a first segment, a second segment, and a bridge, the first segment and the second segment being electrically separated by a gap, and the bridge being electrically coupled to the first segment and the second segment. The circuit board is configured to detect a resistance of the sensor film.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based upon, claims the benefit of, and claims priority to U.S. Provisional Patent Application No. 62 / 895,790, filed on September 4, 2019, and U.S. Provisional Patent Application No. 62 / 892,441, filed on August 27, 2019, which are hereby incorporated by reference in their entirety for all purposes. Background Art

[0003] Certain sensors can be used to detect organic liquids in the presence of other substances. For example, certain sensors can be used to detect hydrocarbons and / or oil in the presence of water, such as hydrocarbon fuel floating on water, spread on a flat surface, or collected in a sump. Such sensors can also be used to improve the safety of diesel generators used for backup power by detecting potential leaks. Sensors can also be used to detect leaks near oil storage tanks used for oil boilers or other heating-related equipment in commercial buildings for the same purpose. Sensors can also be used to detect hydrocarbons and / or oil over a range of temperatures and in dry conditions without water.

[0004] It is important that the sensor does not respond to water simply because the sensor may be placed in contact with water in a sump or placed outdoors (e.g., and subject to rain). The sensor may be configured to detect potential hydrocarbons and / or oil by changing the value of an electrical characteristic, such as the resistance of the sensor, in the presence of hydrocarbons and / or oil. Water, either alone or in addition to hydrocarbons and / or oil, should not significantly affect the electrical characteristic being detected.

[0005] Additionally, the sensor may corrode or otherwise be damaged by extensive contact with water. Once corroded, the sensor may not function properly within the originally specified temperature range and / or wet and dry conditions. Summary of the Invention

[0006] The present invention addresses the need for a sensor configured to detect hydrocarbons and / or oil in wet and dry conditions over a range of temperatures while providing better protection against corrosion and / or wear than previous sensors.

[0007] In some embodiments, an organic liquid sensor is provided that is configured to output a signal corresponding to the presence of one or more organic liquids. The sensor includes a circuit board and a sensor film deposited on the circuit board. The sensor film includes a first segment, a second segment, and a bridge portion. The first segment and the second segment are electrically separated by a gap, and the bridge portion is electrically coupled to the first segment and the second segment. Furthermore, the circuit board is configured to detect the resistance of the sensor film.

[0008] In some embodiments, an organic liquid monitoring system is provided. The system includes a controller and an organic liquid sensor. The controller includes a memory and a processor. The organic liquid sensor is configured to output a signal corresponding to a presence of one or more organic liquids and includes a circuit board. The circuit board is configured to detect a resistance of a sensor film deposited on the circuit board. The sensor film includes a first segment, a second segment, and a bridge, where the first segment and the second segment are electrically separated by a gap, and the bridge is electrically coupled to the first segment and the second segment. Further, the controller is coupled to the organic liquid sensor and is configured to receive the signal corresponding to the presence of the one or more organic liquids.

[0009] In some embodiments, an organic liquid sensor is provided that is configured to output a signal corresponding to a presence of one or more organic liquids. The organic liquid sensor includes a circuit board, an electronic monitoring circuit including a first terminal and a second terminal, and a sensor film. The sensor film is deposited on the circuit board and includes a first segment, a second segment, and a bridge. The first terminal is electrically coupled to the first segment, and the second terminal is electrically coupled to the second segment, where the first terminal, the first segment, the bridge, the second segment, and the second terminal are electrically coupled in series without exposed conductive metal. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 A view of a sensor is shown in accordance with some embodiments of the present invention.

[0011] Figure 2A A top view of a circuit board schematic is shown in accordance with some embodiments of the present invention.

[0012] Figure 2B A bottom view of a circuit board schematic is shown in accordance with some embodiments of the present invention. Figure 2A

[0013] Figure 3 A partial top view of an organic liquid sensor after a corrosion test is shown in accordance with some embodiments of the present invention.

[0014] Figure 4 A side view of a sensor assembly is shown in accordance with some embodiments of the present invention.

[0015] Figure 5A A sensor assembly positioned outside of an overfilled tank is shown in accordance with some embodiments of the present invention. Figure 4

[0016] A sensor assembly positioned near a top of a liquid held in a tank is shown in accordance with some embodiments of the present invention. Figure 5B Figure 4

[0017] Figure 5C ​​​sensor assembly positioned outside of a tank with a leak. Figure 4

[0018] Figure 5D sensor assembly positioned outside of a tank with a purposeful discharge of liquid held in the tank. Figure 4

[0019] Figure 6 A view of another sensor according to some embodiments of the application is shown.

[0020] Figure 7A A graph of resistance of sensors with various fungicide concentrations for a first sensor type according to some embodiments of the application is shown.

[0021] Figure 7B A graph of resistance of sensors with various fungicide concentrations for a second sensor type according to some embodiments of the application is shown.

[0022] Figure 8 A schematic view of a monitoring system according to some embodiments of the application is shown. DETAILED DESCRIPTION

[0023] Figure 1 A sensor 100 according to some embodiments of the application is illustrated. As will be described in detail below, the sensor 100 can include various electronic components configured to sense organic liquids including, but not limited to, diesel fuel, gasoline, and / or jet fuel, and output a signal indicative of the presence of such organic liquids and / or the relative concentration of the organic liquids. As shown, the sensor 100 can include a circuit board 104 such as a printed circuit board, an electronic monitoring circuit 108, and a sensing component 110 including a sensor film 112. Figure 1

[0024] In some embodiments, the electronic monitoring circuit 108 can include one or more resistors, capacitors, operational amplifiers, diodes, connectors such as jumpers, and / or other electrical components mounted to the circuit board 104, for example, via surface mount methods and / or through-hole mounting known in the art. The electronic monitoring circuit 108 can be configured to receive power from an external source and / or output a signal indicative of the presence or absence of organic fluids on the sensor 100 and / or the relative concentration of the sensed organic liquids via one or more connectors. In some embodiments, the electronic monitoring circuit 108 can be encapsulated by a non-conductive material such as an epoxy to protect the electronic monitoring circuit 108 from electrical shorts due to water or other environmental factors.

[0025] ​​​The sensor 100 can also include a sensing component 110 in which a sensor film 112 is deposited on and coupled to a substrate. In some embodiments, the substrate can be the circuit board 104, or a layer such as a base layer (not shown) deposited on and coupled to the circuit board 104. As shown, the electronic monitoring circuit 108 can be coupled to the sensor film 112 at a first terminal 120 and a second terminal 124. The sensor film 112 can be formed of one or more materials, such as an elastomer filled with electrically conductive particles. Further, in some embodiments, the sensor film 112 can be formed of a mildew or fungicide mixed with the elastomer filled with electrically conductive particles in order to increase the anti-fungal properties of the sensor 100, as further described below. Figure 1

[0026] In terms of functionality, the sensor film 112 can swell in the presence of an organic hydrocarbon or oil to be detected, and a subsequent increase in the electrical resistance of the sensor film 112 resulting from such swelling is detected and processed by the associated electronic monitoring circuit 108. More specifically, the electronic monitoring circuit 108 can be configured to sense the electrical resistance between the first terminal 120 and the second terminal 124. Further, the electronic monitoring circuit 108 can be configured to output a signal corresponding to the electrical resistance between the first terminal 120 and the second terminal 124. This electrical resistance can change based on the presence of the organic hydrocarbon or oil to be detected as a result of these substances causing the sensor film 112 to swell, which affects the connections between the electrically conductive particles. As a result, for example, a sensed electrical resistance above a threshold resistance value can indicate the presence of the organic hydrocarbon or oil. In further examples, the magnitude of the sensed electrical resistance can be related to the relative concentration of such organic hydrocarbon or oil.

[0027] In order to provide a fast detection signal (i.e., to respond quickly to the presence of an organic fluid), the sensor film 112 can be deposited thinly on the circuit board 104. Further, in some embodiments, the sensor film 112 can be deposited on a single side of the circuit board 104, which can increase the corrosion resistance of the sensor 100, as will be explained below. In some embodiments, the sensor film 112 can be deposited on top of a base layer deposited on top of the circuit board 104. The sensor film 112 and / or the base layer can be deposited only on non-conductive portions of the surface of the circuit board 104. For example, the non-conductive portions can include surfaces in which the resin covers the copper layer of the circuit board 104.

[0028] ​The present disclosure provides organic liquid sensors, such as sensor 100, which can provide higher corrosion resistance than previous sensors. As will be explained below, by depositing sensor film 112 in a "horseshoe" pattern or a "U" pattern on a single side of circuit board 104, the corrosion resistance of sensor 100 can be increased. Additionally or alternatively, prior to depositing base layer and / or sensor film 112, the surface of circuit board 104 can be treated by surface etching or otherwise to increase the corrosion resistance of sensor 100.

[0029] For example, sensor film 112 can be deposited onto circuit board 104 and / or base layer and coupled to circuit board 104 and / or base layer in a general horseshoe pattern or U pattern, which can increase the corrosion resistance of sensor 100 by eliminating exposed material that can be prone to corrosion. As shown, sensor film 112 can include a bridge 112C forming a U shape, a first segment 112A, and a second segment 112B. First segment 112A and second segment 112B can be physically and electrically separated by a gap 116. In particular, first segment 112A and second segment 112B can be physically and electrically separated at least near first terminal 120 and second terminal 124. In some embodiments, gap 116 can extend through circuit board 104 and / or base. In some embodiments, gap 116 can be created by depositing a mask on a portion of circuit board 104 or base layer, depositing sensor film 112 on circuit board 104, base, and / or mask after depositing the mask, and removing the mask. Bridge 112C physically and electrically connects first segment 112A and second segment 112B. In other words, bridge 112C is electrically coupled to first segment 112A and second segment 112B. The separation caused by gap 116 allows current to travel through sensor film 112 from first terminal 120 to second terminal 124 (or alternatively from second terminal 124 to first terminal 120), thereby allowing the resistance of sensor film 112 to be determined. Figure 1

[0030] ​Furthermore, the sensor film 112 can be coupled to the first terminal 120 and the second terminal 124 without using a conductive bridge made of a material susceptible to potential corrosion. In some embodiments, the sensor film 112 can be deposited directly on top of the first terminal 120 and the second terminal 124, each of which can include a pad made of a conductive material such as copper. In embodiments that include a primer layer, the primer layer can be deposited only on the non-conductive portions of the surface of the circuit board 104, thereby allowing the sensor film to be coupled directly to the first terminal 120 and the second terminal 124. Furthermore, the design of the sensor film 112 can significantly reduce or completely eliminate any exposed conductive material (e.g., a conductive metal such as copper, silver, etc.) from the surface of the sensor 100, thereby leaving only the non-conductive portions of the circuit board 104 (which can include resin) and the sensor film 112 exposed to the external environment. The reduction or elimination of exposed conductive material can improve the corrosion resistance of the sensor 100 under certain conditions, such as when the sensor 100 is exposed to and / or submerged in saltwater. Thus, in some embodiments, the first terminal 120, the first segment 112A, the bridging portion 112C, the second segment 112B, and the second terminal 124 are electrically coupled in series without any exposed conductive metal.

[0031] Furthermore, in some embodiments, the circuit board 104 is treated in order to increase the corrosion resistance and durability of the sensor 100. In one example, the circuit board 104 can be treated using a technique such as a plasma treatment prior to depositing the primer layer. The treatment can activate the surface of the circuit board 104, which can improve the adhesion of the primer layer. Furthermore, the treatment can potentially physically roughen the surface of the circuit board 104, but can not be needed to improve adhesion. Additionally or alternatively to the above, other physical roughening treatments (e.g., mechanical abrasion) or chemical roughening treatments (e.g., other primer layers or coupling agents) can be applied to the surface of the circuit board 104. Once treated via one or more of the above treatments, the surface of the circuit board 104 can be referred to as a treated surface.

[0032] After the base layer has been deposited onto the treated surface, the sensor membrane 112 can then be deposited on top of the circuit board 104 and / or the base layer. Treating the circuit board 104 can improve the adhesion of the sensor membrane 112 to the base layer and / or the circuit board 104. Improved adhesion has also been shown to increase the overall corrosion resistance of the sensor 100. Additionally, the adhesion improvement treatment of the circuit board 104 can also increase the durability of the sensor under freeze-thaw conditions, which are common in certain places where the sensor is used with organic liquids. Finally, as mentioned above, treating the circuit board 104, as well as reducing and / or eliminating exposed conductive material, can allow the sensor 100 to function in saltwater, which is typically more corrosive than freshwater, for extended periods of time. It is contemplated that a top layer, such as a protective coating or film, can be applied on top of the sensor membrane 112 in order to further protect the sensor membrane 112 without interfering with the organic liquid sensing capabilities of the sensor 100.

[0033] Treating the circuit board 104 to improve adhesion and / or depositing the base layer can still allow the sensor membrane 112 to be deposited as a thin layer, as with previous sensors, and thus not significantly impact the organic liquid sensing performance of the sensor 100. In some embodiments, the sensor 100 can detect as little as 2 mm of fuel floating on the surface of water. Additionally, the sensor 100 can detect certain light or medium weight fuels, such as diesel fuel, jet fuel, or gasoline, in as little as two seconds, and can be approved to detect diesel fuel in less than thirty seconds under the FM 7745 approval standard. The sensor 100 can accurately detect the presence of an organic liquid in the presence of water. In some embodiments, the sensor membrane 112 can include one or more materials configured to absorb the organic liquid(s) while repelling water (e.g., an elastomer filled with conductive particles, as mentioned above). Thus, in some embodiments, the sensor membrane 112 can generally be hydrophobic.

[0034] In some embodiments, to provide protection against mold and / or fungus, the sensor membrane 112 can be formed from a fungicide or mildewcide mixed with the elastomer filled with conductive particles. For example, in some embodiments, a mildewcide such as MX-3, distributed by CFI Products Company, can be mixed with the elastomer filled with conductive particles to form an initial mixture that can be deposited to form the sensor membrane 112. MX-3 contains the active ingredient 3-Iodo-2-Propynyl Butylcarbamate, as shown in formula (1) below:

[0035]

[0036] If the antimicrobial agent is mixed into the elastomer in a rough percentage, such as 1.3% to 2.5% by weight of the initial mixture if the antimicrobial agent is MX-3, the organic liquid sensing performance of the sensor 100 can be minimally affected while the antifungal and / or mold growth of the sensor 100 can be significantly improved. Once the initial mixture is dried and forms the sensor film 112, the final concentration of the antimicrobial agent in the sensor film 112 can be different than the concentration in the initial mixture. In the case of using MX-3 as the antimicrobial agent, the final weight concentration in the sensor film 112 can include 3.4% to 6.6% by weight of the antimicrobial agent.

[0037] An advantage of using MX-3 as the antimicrobial agent is that MX-3 is readily mixed with the other components of the initial mixture of the sensor film 112. For example, in an initial mixture that includes xylene, silicone, and a graphite material, MX-3 is readily dispersed in the xylene at a temperature of 70°F (i.e., room temperature). It is contemplated that a fungicide and / or antimicrobial agent other than MX-3 can be used so long as the selected fungicide and / or antimicrobial agent is readily dispersed in one or more of the liquid components (e.g., xylene) to be relatively uniformly dispersed throughout the sensor film 112.

[0038] Referring to Figure 2A and Figure 2B , respectively, top and bottom views of a circuit board schematic are shown. In some embodiments, the circuit board 200 of Figure 2A and Figure 2B may be the same as the circuit board 104 described above with respect to Figure 1 . For example, the electronic monitoring circuit 204, which can include one or more resistors, capacitors, operational amplifiers, diodes, connectors such as jumpers, and / or other electrical components, can be mounted to the circuit board 200 via surface mount methods and / or through holes known in the art. In particular, the electronic monitoring circuit 204 can include connectors 208 mounted to the bottom of the circuit board 200, as shown in Figure 2B , while other components included in the electronic monitoring circuit 204 can be mounted to the top of the circuit board 200, as shown in Figure 2A .

[0039] The circuit board 200 can include a planar surface 206 upon which a portion of a sensor film (e.g., the sensor film 112 in Figure 1 ) can be disposed. In some embodiments, at least some of the first segment 112A, the second segment 112B, and the bridge 112C can be disposed on the planar surface 206. In some embodiments, the entire sensor film 112, including the entire first segment 112A, the entire second segment 112B, and the entire bridge 112C, can be disposed on the planar surface 206.

[0040] Referring toFigure 3 FIG. 11 illustrates a portion of an organic liquid sensor 300 after an erosion test. The organic liquid sensor 300 includes a sensor film disposed on a single surface, the sensor film formed in a U-shape, and manufactured by roughening the circuit board prior to depositing the base layer, followed by depositing the sensor film on top of the base layer (as described above). As a result of the erosion test, the organic liquid sensor 300 did not exhibit significant erosion, which can be due to the features described above.

[0041] Reference is made to Figure 4 FIG. 12 illustrates a sensor assembly 400, in accordance with some embodiments. The sensor assembly 400 can be used to detect organic liquids containing hydrocarbons such as, but not limited to, gasoline, jet fuel, diesel fuel, and / or oil in a temperature range (e.g., -40°C to 85°C) under wet conditions and dry conditions without water. The sensor assembly 400 can include a sensor (not shown) such as the sensor 100 described above with respect to FIG. 1. The sensor assembly 400 can include a housing including a housing tube 404, an end cap 412, and a mesh 420. The sensor can be positioned inside the housing. The housing can then provide mechanical protection such as abrasion protection for the sensor assembly 400. In some embodiments, the housing tube 404 can be made of a rigid plastic or other rigid material that is water resistant and does not interfere with the ability of the sensor to detect organic liquids. Figure 1

[0042] The housing tube 404 can include one or more openings 408. The openings 408 can be large enough in size to allow fluids such as water and / or organic liquids to reach the sensor, while at the same time can be small enough in size to allow the housing tube 404 to protect the sensor from other physical damage (e.g., damage from elements such as rocks). The mesh 420 can be coupled to a distal end of the housing tube 404 opposite the end cap 412. The mesh 420 can be sized so as to protect the sensor from rocks and other debris, while allowing the sensor to access fluids such as water and / or organic liquids.

[0043] The housing tube 404 can be coupled to the end cap 412. The end cap 412 can be further coupled to or provide access for a jumper cable 416 that is in electrical communication with the sensor. More specifically, the jumper cable 416 can be coupled to a connector of a circuit such as the electronic monitoring circuit 108 described above. The jumper cable 416 can be coupled to and in communication with a controller (not shown) in order to provide power to the sensor and / or provide signals from the sensor to the controller.

[0044] The sensor assembly 400 can be used in a variety of different environments. For example, with reference to Figure 5A , Figure 5B ,​Figure 5C and Figure 5D various environments in which the sensor assembly 400 can be used are shown. Figure 5A The sensor assembly 400 is shown positioned outside of a tank 500 that has overflowed. When the tank 500 overflows, the sensor assembly 400 can detect whether the liquid 516 that overflowed the tank 500 contains certain organic liquids.

[0045] Figure 5B The sensor assembly 400 is shown positioned near the top 524 of a liquid 520 held in a tank 504. If certain organic liquids are present in the tank, the organic liquids can float to the top of the tank. The sensor assembly 400 can then detect whether the tank 504 has been contaminated with certain organic liquids.

[0046] Figure 5C The sensor assembly 400 is shown positioned outside of a tank 508 that has a leak. When the tank 504 leaks, the sensor assembly 400 can detect whether the liquid 528 that leaked from the tank 504 contains certain organic liquids.

[0047] Figure 5D The sensor assembly 400 is shown positioned outside of a tank 512 that is purposefully draining a liquid 532 held in the tank 512. While the tank 512 is draining the liquid 532, the sensor assembly 400 can detect whether the liquid 532 contains certain organic liquids.

[0048] Referring to Figure 6 another sensor 600 according to some embodiments is shown. As will be described in detail below, the sensor 600 can include various electronic components configured to sense organic liquids including diesel fuel, gasoline, and / or jet fuel, and output a signal indicative of whether organic fluids are present and / or a relative concentration of the organic liquids. As shown in Figure 6 the sensor 600 can include a circuit board 604 such as a printed circuit board, an electronic monitoring circuit 608, and a sensing component 610.

[0049] The electronic monitoring circuit 608 can include one or more resistors, capacitors, operational amplifiers, diodes, connectors such as jumpers, and / or other electrical components mounted to the circuit board 604, for example, via surface mount methods and / or through-hole mounting known in the art. The electronic monitoring circuit 608 can be configured to receive power from an external source and / or output a signal indicative of whether organic fluids are present and / or indicative of a relative concentration of the organic liquids via one or more connectors. In some embodiments, the electronic monitoring circuit 608 can be encapsulated by a non-conductive material such as an epoxy to protect against electrical shorts due to water or other environmental factors.

[0050] As Figure 6As shown, the sensing component 610 can include a first sensor film layer 612 deposited on and coupled to a substrate 611. The substrate 611 can be a first surface of the circuit board 604. The electronic monitoring circuit 608 can be coupled to the first sensor film layer 612. Further, the electronic monitoring circuit 608 can be coupled to a second sensor film layer (not shown) deposited on a second surface of the circuit board 604 opposite the first surface.

[0051] The first sensor film layer 612 and the second film layer can be coupled to one another by a bridging electrode (not shown) composed of a conductive material such as copper, silver, gold, platinum, etc. The bridging electrode can be formed by leaving a conductive trace on each side of the circuit board 604 adjacent to the second end 616 of the circuit board 604. The conductive traces adjacent to the second end 616 of the circuit board can be electrically coupled, for example, via plated vias, jumpers, etc. The first sensor film layer 612, the bridging electrode, and the second film sensor layer then form an electrical path from a first terminal or node of the electronic monitoring circuit 608 to a second terminal or node of the electronic monitoring circuit 608, and the electronic monitoring circuit 608 can be configured to sense a resistance of the electrical path.

[0052] The first sensor film layer 612 and the second film layer can be formed of the same materials as the sensor film 112 described above. In particular, the first sensor film layer 612 and the second film layer can be formed of a material including a mildewcide such as MX-3. To provide a fast detection signal (i.e., a fast response to the presence of an organic fluid), the first sensor film layer 612 and the second film layer can each be deposited thinly on the circuit board 604.

[0053] Referring now to Figure 7A and Figure 7B , resistance values of various sensors are shown during a test period. More specifically, various sensor film formulations were tested with varying concentrations of a mildewcide, specifically MX-3. The sensor with formulation "A" had a sensor film including xylene, Dow 1-2620, graphite, and MX-3, with a concentration of MX-3 in the sensor film of 3.4% by weight when dry (i.e., a final concentration). The sensor with formulation "E" had a sensor film including xylene, Dow 1-2620, graphite, and MX-3, with a concentration of MX-3 in the sensor film of 6.6% by weight when dry (i.e., a final concentration). The sensor with formulation "B" had a sensor film including xylene, Dow 1-2620, graphite, and MX-3, with a concentration of MX-3 in the sensor film of 12.5% by weight when dry (i.e., a final concentration). The sensor with formulation "F" had a sensor film including xylene, Dow 1-2620, graphite, and no amount of MX-3 (i.e., a concentration of 0%).

[0054] Each sensor recipe is used in sensors that use two different construction types: Type 1 ( Figure 7A The results shown in ) and type 2 ( Figure 7B The "Type 1" construction type is a sensor comprising multiple sensor membrane layers, such as those described above with respect to Figure 6 The sensor 600 described. A "Type 2" construction type is a sensor that includes a sensor membrane deposited on a single surface of the sensor, such as described above with respect to Figure 1 The sensor 100 is described.

[0055] As mentioned above, the sensor can sense the resistance of the sensor membrane to determine the presence of an organic liquid. More specifically, a threshold resistance value corresponding to the presence of an organic liquid can be determined for each sensor membrane. In the case of both Type 1 and Type 2 sensors without a mildewcide, the threshold resistance value is 20 kilo-ohms (kΩ). As will be explained below, adding a mildewcide at an appropriate concentration to the initial mixture of the sensor membrane can minimally affect the resistance characteristics of the sensor membrane compared to a sensor membrane without a mildewcide, thereby allowing mildewcide-enhanced sensors to be used with the same threshold resistance value.

[0056] like Figure 7A and Figure 7B As shown, for each membrane formulation and sensor type, the "dry resistance" of the sensor membrane was measured. Dry resistance is the resistance of the dried sensor membrane before immersion in water. Each sensor was then immersed in water for 21 days, with sensor membrane resistance measurements taken after 1 day, 13 days, and 21 days. The resistance of the sensor membrane is important because if the resistance of the sensor membrane is too close to the threshold resistance value when not in contact with the organic fluid, the sensing performance of the sensor is reduced. Figure 7A and Figure 7B As shown in Table 1 below (Table 1 shows resistance values ​​for various formulations and sensor types), the resistance of sensors with formulations A and E (having 3.4% and 6.6% mildewcide, respectively) was not significantly different from that of the formulation F sensor (0% mildewcide) for both sensor types 1 and 2. The sensor with formulation B (12.5% ​​mildewcide) showed a significantly increased resistance compared to the other formulations, indicating that a 12.5% ​​mildewcide concentration may be too high for some sensor applications.

[0057]

[0058]

[0059] The sensors with formulations A, E, and F were then tested to determine how well the sensors could detect an organic liquid after a 21 day immersion period. The response time of each sensor was measured by placing each sensor in contact with the fuel and timing how long it took for the resistance of each sensor to reach a threshold resistance value. The sensors with formulation F had an average response time of 35 seconds, the sensors with formulation A had an average response time of 21 seconds, and the sensors with formulation E had an average response time of 34 seconds. As such, all of the average response times were within a normal range of typical response times.

[0060] Based on the resistance test results, three samples of the dry conductive film with formulation A (mold inhibitor concentration 3.4%), three samples of the dry conductive film with formulation E (mold inhibitor concentration 6.6%), and three samples of the dry conductive film with formulation F (0% mold inhibitor) have been submitted for synthetic polymeric material fungus resistance testing under ASTM G21-15. After 28 days of incubation, only the three samples with formulation F had some fungus growth, indicating that the sensor film with a mold inhibitor concentration of 3.4% or 6.6% can better prevent fungus growth than the sensor film without a mold inhibitor.

[0061] In view of the above, a sensor including a sensor film with a mold inhibitor concentration of 3.4-6.6% by dry weight, such as the sensor 100 or the sensor 600 described above, can sense an organic liquid with sufficient response time and prevent fungus growth. It is expected that a sensor film with a mold inhibitor concentration of greater than 6.6% by dry weight and less than 12.5% by dry weight can have an acceptable resistance level in water and sufficient response time for use in an organic liquid sensor. It is also expected that a sensor film with a mold inhibitor concentration of less than 3.4% by dry weight can have an acceptable resistance level in water and sufficient response time for use in an organic liquid sensor.

[0062] Figure 8 A monitoring system 800 according to some embodiments is illustrated. The monitoring system 800 can be used to monitor for the presence of an organic liquid in one or more areas. In some embodiments, the monitoring system 800 can include a controller 804, a sensor 824, and a process automation system 828. In some embodiments, the controller 804 can include a processor 808, a memory 812, one or more inputs 816, and one or more communication systems 820.

[0063] In some embodiments, the controller 804 can be coupled to the sensor 824 to provide power to the sensor and / or receive signals from the sensor 824. In some embodiments, the sensor 824 can be a sensor 100 and / or a sensor 600 of the Figure 1 Figure 6 ​In some embodiments, the controller 804 can be coupled to a process automation system 828 to provide signals (e.g., raw signals or formatted versions of the signals) from the sensor 824 to the process automation system 828, which can provide remote monitoring of the sensor 824. For example, in some embodiments, the sensor 824 can transmit raw signals, processed resistance measurements, signals indicative of the presence / absence of a substance (e.g., high / low signals based on a comparison of a sensed resistance measurement to a threshold resistance value), or other signals to the controller 804. Further, in some embodiments, the controller 804 can be coupled to multiple sensors 824.

[0064] In some embodiments, the processor 808 can be any suitable hardware processor or combination of processors, such as a central processing unit (CPU), a graphics processing unit (GPU), a microcontroller (MCU), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), etc. In some embodiments, the input 816 can include any suitable input device and / or sensor that can be used to receive signals from the sensor 824. In some embodiments, the memory 812 can include any suitable storage device or devices that can be used to store instructions, values (such as threshold resistance values), etc., that can be used by the processor 808 to communicate with the process automation system 828 via the communication system(s) 820, etc. The memory 812 can include any suitable volatile memory, non-volatile memory, storage, or any suitable combination thereof. For example, the memory 812 can include RAM, ROM, EEPROM, one or more flash drives, one or more hard drives, one or more solid state drives, one or more optical drives, etc. In some embodiments, the memory 812 can have encoded thereon a computer program for controlling the operation of the controller 804.

[0065] In some embodiments, the communication system 820 can include one or more transceivers, one or more communication chips and / or chipsets, etc. In more particular examples, the communication system 820 can include software, hardware, and / or firmware that can be used to establish Wi-Fi connections, Bluetooth connections, cellular connections, Ethernet connections, etc.

[0066] Those skilled in the art will appreciate that, while the application has been described above in connection with specific embodiments and examples, the application need not necessarily be limited to any particular embodiments or examples, and that many other embodiments, examples, uses, and modifications of the application, and variations thereon, will be apparent to those skilled in the art. The entire disclosure of each of the publications and references cited herein are hereby incorporated by reference. Various features and advantages of the application are set forth in the following claims.

Claims

1. An organic liquid sensor, the sensor being configured to output a signal corresponding to the presence of one or more organic liquids, and the sensor comprising: circuit boards; an electronic monitoring circuit mounted on a first end of the circuit board, wherein the circuit board includes a non-conductive surface extending from the electronic monitoring circuit to an opposite second end of the circuit board; and a sensor film deposited on the non-conductive surface of the circuit board, the sensor film comprising a first segment on a first side of the circuit board, a second segment on the first side of the circuit board, and a bridge portion on the first side of the circuit board, the first segment and the second segment being electrically and physically separated by a gap extending through the circuit board, and the bridge portion being electrically coupled to the first segment and the second segment, wherein the first segment, the second segment, and the bridge portion comprise the same material and are deposited on the non-conductive surface, wherein at least a portion of the non-conductive surface of the circuit board is etched to improve adhesion of the sensor membrane to the circuit board, Wherein, the electronic monitoring circuit is configured to detect the resistance of the sensor membrane.

2. The sensor according to claim 1, wherein The bridge is directly coupled to the first segment and the second segment.

3. The sensor according to claim 1, wherein The circuit board includes a planar surface, and wherein the first segment, the second segment, and the bridge are arranged on the planar surface.

4. The sensor according to claim 1, wherein The electronic monitoring circuit includes a first terminal electrically coupled to the first segment and a second terminal electrically coupled to the second segment.

5. The sensor according to claim 4, wherein The first terminal, the first segment, the bridge portion, the second segment, and the second terminal are electrically coupled in series without any conductive metal being exposed to the element.

6. The sensor according to claim 1, wherein The one or more organic liquids include at least one of diesel fuel, gasoline, or jet fuel.

7. The sensor according to claim 1, wherein The electronic monitoring circuit is coupled to the sensor membrane and is configured to determine a resistance of the sensor membrane and output a signal corresponding to the presence of the one or more organic liquids based on the resistance of the sensor membrane.

8. The sensor according to claim 7, wherein The electrical resistance of the sensor film increases in the presence of the one or more organic liquids.

9. The sensor according to claim 1, wherein The sensor film is deposited in a U-shaped pattern on the first side of the circuit board.

10. The sensor of claim 1, further comprising a substrate layer deposited on the non-conductive surface, wherein The sensor film is deposited on the base layer.

11. The sensor according to claim 1, wherein The sensor membrane comprises an elastomer filled with conductive particles.

12. The sensor according to claim 1, wherein The sensor is configured to be coupled to a controller and to output the signal to the controller.

13. An organic liquid monitoring system, comprising: a controller comprising a memory and a processor; and An organic liquid sensor configured to output a signal corresponding to the presence of one or more organic liquids, the organic liquid sensor comprising: a circuit board configured to detect the resistance of a sensor film deposited on the circuit board, an electronic monitoring circuit mounted on a first end of the circuit board, wherein the circuit board includes a non-conductive surface extending from the electronic monitoring circuit to an opposite second end of the circuit board, the sensor film being deposited on the non-conductive surface of the circuit board, the sensor film comprising a first segment on a first side of the circuit board, a second segment on the first side of the circuit board, and a bridge portion on the first side of the circuit board, the first segment and the second segment being electrically and physically separated by a gap extending through the circuit board, and the bridge portion being electrically coupled to the first segment and the second segment, wherein the first segment, the second segment and the bridge portion comprise the same material and are deposited on the non-conductive surface, wherein at least a portion of the non-conductive surface of the circuit board is etched to improve adhesion of the sensor membrane to the circuit board, The controller is coupled to the organic liquid sensor and is configured to receive a signal corresponding to the presence of one or more organic liquids.

14. The system according to claim 13, wherein: The circuit board includes a planar surface, and wherein the first segment, the second segment, and the bridge are arranged on the planar surface.

15. An organic liquid sensor configured to output a signal corresponding to the presence of one or more organic liquids, the sensor comprising: circuit boards; an electronic monitoring circuit, wherein the electronic monitoring circuit is mounted on the circuit board; and a U-shaped sensor film deposited on a surface of the circuit board, the U-shaped sensor film comprising a first segment, a second segment, and a bridge portion between the first segment and the second segment, the first segment and the second segment being electrically separated by a gap, and the bridge portion being electrically coupled to the first segment and the second segment, wherein the first segment, the second segment, and the bridge portion comprise the same material, wherein the electronic monitoring circuit is located on the surface of the circuit board adjacent to a first end of the circuit board, and the bridge portion is located on a non-conductive portion of the surface of the circuit board adjacent to an opposite second end of the circuit board, Wherein, the electronic monitoring circuit is configured to detect the resistance of the sensor membrane.

16. The organic liquid sensor according to claim 15, wherein The gap extends through the circuit board.

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