Adhesive Dispensing System and Method

Abstract

An electrical property sensor is presented that includes a printed circuit board having a first side separated from a second side by a thickness, the first side having a length and a width. The sensor also includes an opening extending from the first side of the printed circuit board to the second side of the printed circuit board. The opening includes a receiving electrode and a transmitting electrode. When a fluid flows through the opening and a voltage is supplied to the transmitting electrode, a current is measured at the receiving electrode.

Description

[Background technology]

[0001] Systems for dispensing adhesive typically include an inlet or interior area that holds the adhesive and an outlet or tip where the adhesive is dispensed onto a surface. The flow rate of the adhesive can be directly controlled using a metering system to meet the needs of the downstream manufacturing process. Many systems dispense multiple components that mix together in a mixing chamber. Thus, there is a general need to more accurately measure mix quality and other dispensing parameters in a timely and cost-effective manner. Summary of the Invention

[0002] An electrical property sensor is presented that includes a printed circuit board having a first side separated from a second side by a thickness, the first side having a length and a width. The sensor also includes an opening extending from the first side of the printed circuit board to the second side of the printed circuit board. The opening includes a receiving electrode and a transmitting electrode. When a fluid flows through the opening and a voltage is supplied to the transmitting electrode, a current is measured at the receiving electrode.

[0003] Systems and methods including such sensors allow for direct contact between the sensor and the fluid flowing through the dispenser, as the sensors herein are cost-effective to manufacture and can be disposed of after use. The systems and methods herein also allow for multiple sensor signals to be collected across the fluid flow, providing real-time information about material entering and exiting the mixing area. The systems and methods herein also allow for the detection and removal of air bubbles. The systems and methods herein allow dispensing systems and their operators to change operating parameters during operation to address issues as they occur, or potentially before they occur, resulting in less wasted material and more accurate dispensing.

[0004] The above summary of the disclosure is not intended to describe each of the disclosed embodiments or all implementations of the disclosure. The following description more particularly illustrates exemplary embodiments. In several places throughout this application, guidance is provided through the enumeration of examples, which can be used in various combinations. In each instance, the recited items serve only as a representative group and should not be construed as an exclusive enumeration. Thus, the scope of the disclosure should not be limited to the specific exemplary structures described herein, but extends to at least the structures described by the language of the claims, and equivalents of these structures. Any of the elements expressly enumerated herein as alternatives can also be expressly included or excluded from the claims in any combination as desired. Various theories and possible mechanisms may be discussed herein, but in no event should such discussion be construed as limiting the subject matter that can be claimed. [Brief description of the drawings]

[0005] [Figure 1] 1 illustrates an adhesive dispenser in which exemplary embodiments may be implemented; [Figure 2A] A parallel PCB material measurement flow sensor is shown. [Figure 2B] A parallel PCB material measurement flow sensor is shown. [Figure 2C] A parallel PCB material measurement flow sensor is shown. [Figure 3A] 1 illustrates a single PCB material measurement flow sensor according to an embodiment herein. [Figure 3B] 1 illustrates a single PCB material measurement flow sensor according to an embodiment herein. [Figure 4A] 1 illustrates a sensor placement in a dispenser according to an embodiment herein. [Figure 4B] 1 illustrates a sensor placement in a dispenser according to an embodiment herein. [Figure 4C] 1 illustrates a sensor placement in a dispenser according to an embodiment herein. [Figure 4D] 1 illustrates a sensor placement in a dispenser according to an embodiment herein. [Figure 4E] 1 illustrates a sensor placement in a dispenser according to an embodiment herein. [Diagram 5] 1 illustrates a method of forming a sensor system according to an embodiment herein. [Figure 6A] 1 illustrates a material measurement flow sensor for use in accordance with embodiments herein. [Figure 6B] 1 illustrates a material measurement flow sensor for use in accordance with embodiments herein. [Figure 7] 1 illustrates a material measurement flow system according to an embodiment herein. [Figure 8] 1 illustrates a method for removing entrapped air bubbles from a fluid line according to an embodiment herein. [Figure 9A] 1 illustrates a materials characterization system in which illustrative embodiments may be implemented. [Figure 9B] 1 illustrates a materials characterization system in which illustrative embodiments may be implemented. [Figure 9C] 1 illustrates a materials characterization system in which illustrative embodiments may be implemented. [Figure 9D] 1 illustrates a materials characterization system in which illustrative embodiments may be implemented. [Figure 9E] 1 illustrates a materials characterization system in which illustrative embodiments may be implemented. [Figure 9F] 1 illustrates a materials characterization system in which illustrative embodiments may be implemented. [Figure 10A] 1 illustrates an example conductivity signal that may be received from an embodiment herein. [Figure 10B] 1 illustrates an example conductivity signal that may be received from an embodiment herein. [Figure 11A] 1 illustrates an example conductivity signal that may be received from an embodiment herein. [Figure 11B] 1 illustrates an example conductivity signal that may be received from an embodiment herein. [Figure 12A] 1 illustrates an example system for detecting entrapped air in a material dispensing system, according to embodiments herein. [Figure 12B] 1 illustrates an example system for detecting entrapped air in a material dispensing system, according to embodiments herein. [Figure 13A] 1 illustrates a stack-up of PCB electrodes according to one embodiment of the present disclosure. [Figure 13B] 1 illustrates a stack-up of PCB electrodes according to one embodiment of the present disclosure. [Figure 13C] 1 illustrates a stack-up of PCB electrodes according to one embodiment of the present disclosure. [Figure 13D] 1 illustrates a stack-up of PCB electrodes according to one embodiment of the present disclosure. [Figure 13E] 1 illustrates a stack-up of PCB electrodes according to one embodiment of the present disclosure. [Figure 13F] 1 illustrates a stack-up of PCB electrodes according to one embodiment of the present disclosure. [Figure 14A] 1 illustrates an example batch detail detection for a material dispensing system. [Figure 14B] 1 illustrates an example batch detail detection for a material dispensing system. [Figure 15] 1 illustrates a method of using a material measurement flow sensor according to an embodiment herein. [Figure 16] 1 illustrates a dispensing system in which exemplary embodiments may be implemented. [Figure 17A] 1 illustrates a conductivity measurement system in an exemplary network architecture. [Figure 17B] 1 illustrates a conductivity measurement system in an exemplary network architecture. [Figure 17C] 1 illustrates a conductivity measurement system in an exemplary network architecture. [Figure 18] 1 illustrates an exemplary computing device that can be used in embodiments of the present disclosure. [Figure 19] 1 illustrates an exemplary computing device that can be used in embodiments of the present disclosure. [Figure 20] 1 illustrates an exemplary computing device that can be used in embodiments of the present disclosure. [Figure 21A] 3 shows a sensor structure as further described in the Examples. [Figure 21B] 3 shows a sensor structure as further described in the Examples. [Figure 22] 3 shows a sensor structure as further described in the Examples. [Diagram 23] The data presented is further discussed in the Examples. [Figure 24] The data presented is further discussed in the Examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] The present disclosure relates to sensors capable of determining a property of a fluid, and methods for determining the property of a fluid. The present disclosure also relates to data sets received by such sensors, and methods of using the data to analyze the property of the fluid.

[0007] Many industrial processes use liquid materials, such as liquid adhesives, liquid food ingredients, liquid coolants, or liquid reaction products, to name a few. Certain properties of such liquids change over time: adhesives may harden, oils may become less viscous as the temperature increases, and coolants may age and have a lower heat capacity than they initially had.

[0008] However, many industrial processes depend on certain properties of the liquid being within specified ranges or unchanged compared to the properties in the initial state. For example, an adhesive or adhesive mixture may have different curing properties when applied at different temperatures, different mix ratios, etc.

[0009] Co-pending International Application No. IB2021 / 056362, filed July 14, 2021, discloses a property sensor for determining a property value of a liquid, including two PCBs defining a channel through which the liquid flows. While this allows for direct contact between the sensor and the fluid, there is a need for a cost-effective sensor that can provide more contextual information about material mixing. Embodiments herein provide systems and methods for effectively and accurately measuring material information in a mixing context.

[0010] Described herein are sensors and sensor systems used to measure electrical properties of fluids. Broadly speaking, the sensors herein function by a transmitting electrode that receives a voltage that generates an electric field. As the fluid flows between the transmitting and receiving electrodes, the fluid conducts a current to the receiving electrode. The term "sensor" as used herein can refer to both a physical sensor that provides a sensor signal indicative of the conducted current, and a "sensor system" that includes a processor that calculates the electrical properties of the fluid based on the sensor signal.

[0011] The term "electrical property" is intended to refer broadly to any electrical property of a fluid that can be derived based on impedance measurements of a sensor. The example of impedance measurements is used herein to facilitate understanding of the embodiments. However, it is expressly contemplated that other electrical properties may be calculated and relevant to the embodiments herein. For example, conductivity measurements or permittivity may also be determined from impedance measurements. As shown herein, either conductivity or permittivity may be relevant to determine relevant functionality of a dispensing system or the quality of the fluid flowing therethrough.

[0012] As described herein, the sensors are described as measuring electrical properties of a "fluid." The term "fluid" is intended to be interpreted broadly and to encompass low viscosity liquids, high viscosity liquids, semi-solid materials, suspensions, molten materials, or other flowable materials.

[0013] The sensor is described herein as having one or more "openings" in a "printed circuit board". These terms are intended to be interpreted broadly. For example, an opening may extend completely through the thickness of the sensor along part or all of its length. An opening may have a chamfer along part or all of its perimeter. An opening may be elongated like a slot, or shaped like a circular or oval hole. An opening may have one or more corners or edges, or may have a curvature along part or all of its perimeter. As used herein, a "printed circuit board" refers to a laminated sandwich of conductive and insulating layers. A printed circuit board (PCB) herein may include any number of terminals and conductors that allow a voltage to be applied to a transmitting electrode and a current to be transmitted from a receiving electrode. The PCB may be manufactured using conventional PCB manufacturing techniques or additive manufacturing techniques. As used herein, a PCB is intended to cover any number of layers, with or without edge connectors. Any suitable conductive metal may be used to form the conductive layers. Any suitable insulating material may be used to form the insulating layers.

[0014] The property sensors as described herein can be used to sense the properties of the fluid resulting from the mixing process. They can also be used to sense the properties of the input fluids for the mixing process or industrial manufacturing process. Advantageously, a separate property sensor for each input fluid is placed immediately before the mixer. The data from these property sensors measuring the input fluids can be processed together with the data from the property sensor measuring the mixed fluid, for example in an integrated material property monitoring system. For example, if a fluid composition is mixed from three input fluids, the properties of each of the three fluids before mixing can be determined using three property sensors at the outlets of each of the three vessels containing the three input fluids. This can help with quality control and reduce waste that may otherwise occur due to one of the input fluids being out of specification for a property.

[0015] The sensors described herein may determine various properties of a fluid, such as, for example, the mix ratio of a two-component adhesive, or the cured state of a curable composition, or the aging state. The number of properties previously varied to establish a set of calibration data representing previously measured calibrated impedance responses at various property values ​​determines the number of properties that can be subsequently determined by the property sensor. The pre-stored set of calibration data representing previously measured calibrated impedance responses at one or more sensing frequencies and at various property values ​​of the fluid property forms or represents a multi-dimensional data field specific to the fluid. This data field enables the property value deriver to determine the value of the fluid property from the actual measured response impedance.

[0016] Fluids have many properties such as, for example, viscosity, density, color, content of volatile components, water content, chemical composition, boiling point, as well as aging state, hardening state in the case of a fluid hardenable composition, or mixing ratio if the fluid is a mixture.

[0017] Furthermore, because certain properties of a particular fluid vary with time and / or other parameters, the response impedance in the property sensors described herein also varies with time and / or other parameters. Values ​​of these properties may be derived via the sensors and systems described herein. In addition, variations over time include variations in properties between different production lots of the fluid. Thus, the property sensors described herein can be used to detect differences in certain properties (e.g., chemical composition) of a suitable fluid between later and earlier production lots of the fluid.

[0018] The term "property" of a fluid according to the present disclosure is not particularly limited. For example, as described in the embodiments herein, one property of interest is the mixing ratio of two or more components of the fluid. In some of these embodiments, the fluid is a two-component adhesive, and the property of the fluid is the mixing ratio of the components. In other embodiments, the property of interest is the degree of cure or the state of cure. In some of these embodiments, the fluid is a hardenable composition, and the property of the fluid is the degree of cure of the composition.

[0019] In other embodiments, the property of interest is an aging degree or aging state. In some of these embodiments, the fluid is an aging fluid, i.e., a fluid in which a particular property changes over time after the aging fluid is produced. The property sensor may determine the change in response impedance of the aging fluid after some aging, compared to the response impedance of the same fluid recorded at a particular time before and after aging. The property sensor may thereby determine the aging degree or aging state of the fluid.

[0020] A property of a fluid can take on a variety of values, for example, the property "dynamic viscosity" of the fluid "water" can take on values ​​such as 1.30 mPa.s or 0.31 mPa.s. Such values ​​are referred to herein as property values. A particular property may not be associated solely with a numerical property value. For example, the property "degree of cure" can have property values ​​such as, for example, "uncured", "partially cured", or "fully cured". For example, the property "state of cure" can have property values ​​such as, for example, "uncured" or "fully cured". A fluid according to the present disclosure can be a viscous fluid. A fluid can be a fluid that flows regardless of viscosity. A fluid can be a fluid that flows continuously.

[0021] In certain embodiments, the fluid is a fluid adhesive. In some of these embodiments, the fluid is a curable fluid adhesive. In some of these embodiments, the fluid is a curable two-part fluid adhesive. "Two-part" refers to the adhesive being composed of a first component and a second component that are mixed, for example in a static mixer or a dynamic mixer, to form the adhesive.

[0022] In other embodiments, the fluid is or includes a gap filler, a sealant, a dielectric fluid such as 3M™ Novec™ High Performance Liquids, a thermally conductive interface material such as a thermally conductive gap filler, or a fluid chemical composition for producing any of the foregoing fluids.

[0023] FIG. 1 illustrates an adhesive dispenser in which exemplary embodiments may be implemented. FIG. 1 is a side view of a dispenser and mixing system for a viscous two-component adhesive. A first component A and a second component B of the adhesive are extruded from respective cartridges 100, 110 and pass into a static mixer 120. In the illustrated system 1, at the output 170 of the static mixer, the mixed adhesive passes through a sensing area 50 before being dispensed at the output 190. The sensing area 50 may house a sensor that senses the mixing ratio of components A and B in the mixed adhesive.

[0024] The cartridges 100, 110 contain viscous components A and B, respectively. The respective pistons 130 are moved further into the cartridges 100, 110, pushing out components A and B. The pistons 130 are driven by respective individually controllable motors 140, 150, and the pressure generated by the pistons 130 moves the unmixed components and the mixed viscous adhesive 10 after mixing through the static mixer 120 and the channels 200 of the system. The motors 140, 150 may be part of a feedback loop. If the sensed mixing ratio is outside the acceptable band of the desired mixing ratio, the motors 140, 150 can be individually controlled to push more component A and / or less component B (or vice versa) into the static mixer 120 to adjust the mixing ratio towards the desired mixing ratio. Both motors 140, 150 can be controlled separately to obtain the desired total throughput per second of mixed adhesive to be dispensed.

[0025] The static mixer 120 receives unmixed components A and B of a two-component adhesive at an input end 160. Lamellae inside the static mixer 120 redirect the flow of the input material multiple times, introducing shear forces that help mix components A and B together. An output end 170 of the static mixer 120 is connected to an inlet 180 of a duct piece 200 (shown in longitudinal cross section) that includes a channel and a sensing zone 50. Thus, the mixed adhesive 10 can exit the static mixer 120 and enter the duct piece 200. At an outlet 190 of the duct piece 200, the mixed adhesive is dispensed.

[0026] Within the sensing area 50 may be a sensing system, for example in communication via wires 210 to a computerized control system 220, which provides AC voltages to generate the required electric fields necessary to measure conductivity using a suitable sensing system as described herein.

[0027] The computerized control system 220 has an internal data storage device 230 in which sets of calibration data representing calibration impedance responses are stored. These calibration impedance responses may have been recorded beforehand, i.e. before measurements, during a calibration process in which the same duct piece 200 and the same components A, B are used resulting in the same mixed viscous adhesive 10. During the calibration process, the mixing ratio A / B is adjusted to specific fixed calibration mixing ratios (CMR) and for each of these calibration mixing ratios, a calibration impedance response (CIR) is sensed at five different calibration sensing frequencies (CSF). These data sets are recorded and stored in the data store 230, for example in the form of a triplet of (CMR, CSF, CIR). The data sets form a three-dimensional data field specific to the viscous adhesive. The data sets are used to build a parameterized multidimensional model of the data sets based on multidimensional polynomials. This parameterized model facilitates rapid computational interpolation between individual data sets and rapid derivation of characteristic values ​​for the fluid properties in subsequent measurements. The parameters of the parameterized model form a set of calibration data that represents the data sets recorded during the calibration process.

[0028] Thereafter, when actually measuring the value of the "mix ratio" property of the viscous two-component adhesive of components A and B in the system 1, the measured impedance response (MIR) is measured at each specific measurement sensing frequency (MSF) and recorded in the control system 220. To derive the value of the mix ratio from the measured impedance response at the measurement sensing frequency, software running on the control system 220 identifies the triplet among the set of calibration impedance response triplet having the closest calibration response impedance closest to the measured impedance response and the closest calibration sensing frequency closest to the measurement sensing frequency. This identification and potential interpolation can be easily performed by using a parameterized multi-dimensional polynomial that models multiple data sets, i.e., multiple triplets of (CMR, CSF, CIR). From these calibration data, the software derives the (previously unknown) value of the mix ratio in the actual measurement.

[0029] Often the same sensing frequency used for calibration is also used for measurement. However, a mixing ratio in the measurement may occur where the calibration impedance response has not been determined in the calibration. Thus, both the sensing frequency and the response impedance may not match exactly between the triplets in the calibration data set. In such cases, an interpolation between two suitably selected calibration triplets containing two calibration impedance responses close to the measured response impedance results in an interpolated calibration mixing ratio, which can then be considered as the mixing ratio in the measurement. The interpolation is performed by software on the control system 220 using a parameterized multidimensional polynomial.

[0030] The result of the interpolation and derivation is a value for the mixture ratio of component A to component B in the mixed two-component adhesive 10 in the sensing zone 50 being measured.

[0031] In this embodiment, the calibration impedance response was measured in dependence on two parameters, namely the sensing frequency and the mixing ratio. In other embodiments, the dependence of the impedance response on further parameters can be taken into account, such as the dependence on the temperature of the adhesive in the sensing zone. The data set of the calibration impedance response is then a quadruple of values ​​such as (CMR, CSF, CIR, temperature) and the pre-stored set of calibration impedance responses is a set of quadruples forming a four-dimensional data field that is characteristic of the viscous adhesive. By taking into account further parameters, the data set can be a quintuple of values ​​or even a higher set of values, so that the data set of the calibration impedance response is a multidimensional data field of greater dimension and can be represented by different parameterized multidimensional polynomials.

[0032] The control system 220 may record the value of the mix ratio along with a time stamp for quality assurance. In the illustrated system, the motors 140, 150 that push the respective components A and B into the static mixer 120 are connected to and controlled by the control system 220. The mix ratio derived during the actual measurement is continuously checked against the desired mix ratio. If the deviation from the desired mix ratio is greater than acceptable, the control system 220 may suitably modify the speed of one or both of the motors 140, 150 to adjust the measured mix ratio toward the desired mix ratio. Although motors 140, 150 are illustrated, it is expressly contemplated that the systems and methods herein may also apply to pneumatically actuated dispenser systems, hydraulic systems, cavitation-based systems, precision gear-based systems, peristaltic pump-based systems, or other suitable dispensing systems.

[0033] 1 illustrates an exemplary system in which sensing area 50 is located after mixer 120. However, it is expressly contemplated that in some embodiments sensing area 50 may be located before mixer 120, e.g., positioned to measure parameters related to only material A or B, or may be located elsewhere in the system, e.g., within mixer 120 to measure the progress of mixing.

[0034] 2A-2C show a parallel printed circuit board (PCB) sensor material measurement system. Co-pending PCT Application No. IB2021 / 056362, filed July 14, 2021, describes a material measurement flow sensor as shown in FIGS. 2A-2C. FIG. 2A shows a perspective view of material measurement system 300. FIG. 2B shows a diagram of a pair of PCB sensors 310. FIG. 2C shows a cutaway view of sensing system 300. Sensing system 300 may be located within or instead of a sensing area in a dispensing system, for example. Fluid flows from inlet 302 to outlet 304, or vice versa. As shown in the cutaway view of FIG. 2C, pair of PCB sensors 310, 320 are spaced apart to allow fluid to flow through channel 330. As fluid flows through channel 330, fluid passes between PCB 310 and PCB 320. Each PCB board acts as an electrode, allowing conductivity measurements to be made. By measuring the conductivity over time, it is possible to understand how the mix ratio varies during use (e.g., during steady state operation, at start-up, after a hiatus). This can provide important feedback if the mix ratio falls outside of an acceptable range. The mix ratio can be adjusted automatically or manually in response to an alert, for example, any adhesive dispensed when the mix ratio was outside of an acceptable range can be discarded. Similarly, it may be possible to detect that a partial cure has occurred and that a system purge is required.

[0035] However, while system 300 is capable of obtaining conductivity measurements over time in direct contact with the fluid, system 300 only provides one measurement at a time as the fluid flows through the channel.

[0036] System 300 utilizes two PCBs to act as electrodes (one positive, one negative) to collect a single conductivity measurement for the fluid flow. The system gives a snapshot of the fluid conditions. The systems and methods provided herein and discussed in Figures 3-8 utilize a sensing system that can use less material, potentially providing a more complete picture of the fluid flow conditions. A single PCB acts as a housing for both the positive and negative electrodes along one or more slits. This provides multiple advantages including pressure independence, i.e. system 300 requires no optimization to address pressure changes within the housing and bending of the PCB board under fluid pressure. The pressure drop experienced across the thickness of the PCB board, rather than the width, has only a minor effect. Similarly, temperature dependence is also less for system 400 than system 300, since the PCB material is already optimized for electronics with a low coefficient of thermal expansion. From a material usage standpoint, the ability to use only one PCB to obtain measurements is also an improvement as in the event of material hardening only one PCB board is used instead of two. The cost to produce sensing system 400 is also reduced. Additionally, the system 400 can provide multiple conductivity measurements to provide a better indication of whether mixing is complete across the sensing area.

[0037] 3A and 3B show a material measurement flow sensor according to an embodiment of the present disclosure. FIG. 3A shows a PCB material measurement flow sensor 400. As shown in FIG. 3A, the sensing system 400 includes a PCB substrate 402 having one or more grounds 430 and TX contacts 440. The TX contacts provide a transmit signal to each transmit electrode 410. Four RX contacts (not shown) located on the back side of the PCB receive an indication of the sensed impedance from each of the electrode pairs. The potential of each receive electrode 420 is electronically adjusted to a ground potential separately. In some embodiments, the adjustment action for each receive electrode is interpreted as an impedance signal for each electrode pair. In the illustrated embodiment, four separate measurement channels can provide information through their own TX contacts 440 and RX contacts (not shown).

[0038] In the illustrated embodiment, the sensing system 400 has four electrode pairs, with four transmitting electrodes 410 each paired with one of four receiving electrodes 420. However, it is expressly contemplated that there may be more or fewer electrode pairs depending on the available area on the PCB board and the sensing needs.

[0039] Each electrode pair is separated from the adjacent pair such that four separate conductivity measurements are received, one from each electrode pair 410, 420. In some embodiments, the sensing system 400 is positioned perpendicular to the material flow such that the first sensing area 452 receives a first portion of the material flow, the second sensing area 454 receives a second portion of the material flow, the third sensing area 456 receives a third portion of the material flow, and the fourth sensing area 458 receives a fourth portion of the material flow. Thus, the system 400 can simultaneously generate four different signals for a single material flow to provide a better picture of whether the mix ratio (or other measured parameter) is consistent across the entire sensing area.

[0040] In comparison to previous sensing systems such as those in Figures 1-2, conductivity measurements required both positive and negative electrodes, requiring two PCBs per electrode pair. System 300 can be modified, but requires five PCB boards in a stack with precise spacing between each adjacent PCB board. In contrast, system 400 allows four measurements to be made simultaneously on a single PCB. The system also provides a larger surface area for material flow with shorter sensor distances.

[0041] 3A shows an embodiment in which each electrode pair is part of a slot 452, 454, 456, 458. However, it is contemplated that instead of being closed on both sides, the sensing region may also include a pair of electrodes on a protrusion or within an opening in a "comb" like structure. However, being closed on both ends may be preferred from a structural standpoint, especially with viscous fluids.

[0042] As described further herein, electrodes 410, 420 may be formed by metallization of the inner surfaces of slides 452, 454, 456, 458, for example using copper. The metallization process may connect electrode 420 to electrode 410. A separation or cutting step is therefore necessary. This may be done by breaking the connection, for example by drilling holes at locations 450A and 450B as shown, punching out perforated components, milling, nibbling, etching, laser cutting, or another suitable method.

[0043] The systems and methods herein can be used with a variety of materials to be dispensed. PCB boards often have a maximum operating temperature of less than 170° C., which limits the temperature of the material that can be dispensed through the sensor system 400. Materials can be, for example, about 10 5The material may have a viscosity ranging from 100 to 1000 Pa·s. Higher viscosities may result in the dispensing pressure being insufficient to push the material through the slots 452-458 without destroying the sensors. High viscosity materials may be accommodated, however, by increasing the width of the slots 452-458. However, the sensing system 400 may be less sensitive. Similarly, for materials with particulates, such as suspensions, the particle size must be smaller than the width of the slots 452-458. Additionally, the systems herein may be limited to solvents that do not cause corrosion or otherwise damage to the PCB 402 or electrodes 410, 420.

[0044] FIG. 3B illustrates another embodiment of a sensing system 460 that includes an integrated temperature sensor 470. The temperature sensor 470 is placed in a slot that has a connection point 472 for a ground signal and a connection point 474 for a temperature signal. The ground signal connection point 472 is connected to a ground signal communicator 482. The temperature signal communication point 474 is connected to a temperature signal communicator 476. As with the embodiment of FIG. 3A, there are also four impedance or conductivity sensor slots 480, each connected to a ground signal 482. Note, however, that in the embodiment of FIG. 3B, there are two different spacings between the slots. A first spacing 462 exists between the first slot 480 and the second slot 480 and between the third slot 480 and the fourth slot 480, and a second spacing 464 exists between the second slot 480 and the third slot 480. Increasing the spacing 464 may provide improved shielding against interference between the electromagnetic fields generated by each electrode pair.

[0045] Many mixing processes are at least partially temperature dependent, and material properties such as viscosity change with temperature. Temperature sensors inserted from an external point are often fragile and need to be in the middle of the flow of the material being tested. In the embodiment of FIG. 3B, the temperature sensor is sealed within the housing and kept insulated from the material. The sealing layer can be, for example, a layer of varnish that allows for improved thermal contact to other housing materials. As shown, the temperature sensor connects via contacts 482 on the edge connector.

[0046] 3A-3B show an embodiment in which slots 452-458, 470, and 480 are oval in shape, with generally straight bodies and rounded ends. However, other configurations are possible. Electrodes 410, 420 may, for example, be curved or otherwise shaped to accommodate the available volume of the dispensing system.

[0047] 4A-4C show sensor placement in an adhesive dispenser according to an embodiment herein. Figures 4A-4C show an embodiment in which four electrode pairs are present on a single PCB. However, as discussed herein, it is expressly contemplated that more or fewer electrode pairs may be used.

[0048] The sensor housing may be coupled to a fluid reservoir, for example at the bottom of the cartridge 100 or 110 of the dispenser shown in FIG. 1, or at the end of the mixer 120, for example.

[0049] The material mixture can enter the sensor housing 500 at the input 502 and can exit at the output 504. The sensing system 510 can be received by or disposed within the sensing area 500. In some embodiments, the sensing system 510 is a replaceable sensing system that can be removed from the housing 500 when operation is complete. In some embodiments, the housing 500 includes a self-sealing material to seal the sensing system 510 in place. In some embodiments, an O-ring, gasket, or other compressible material is used as a seal. However, it is expressly contemplated that the sensing system 510 can be integrated into the housing 500 or sealed within the housing 500 so as not to be removable, for example, using an adhesive.

[0050] The sensing system 510 may be a PCB with several slots, protrusions, or openings, each of which may include a pair of electrodes capable of sensing the conductivity of the material mixture when in direct contact with the material mixture. As shown in FIG. 4B, which is a cross-sectional view of the sensing area 500 of FIG. 4A, the material stream 520 may be forced through several channels 522, each of which may include a transmitting electrode and a receiving electrode, thus allowing separate conductivity measurements of the material flow. The combined material stream 524 may exit the sensing area 500 through an outlet 524.

[0051] The sensing area 500 may receive the sensor system 510, for example, in a slot as shown in FIG. 4A. However, other configurations are possible. The sensor system 510 may be a single-use sensor system that is discarded after use when material flow hardens or otherwise degrades components of the system 510.

[0052] Figure 4C shows a sensor system having a connector 534 connecting a dispenser 532 to a sensor unit 536. Figures 4D-4E show cross-sectional views of a dispensing system similar to system 530, for example.

[0053] FIG. 4D illustrates the insertion angle 544 of the PCB 542 after insertion. The PCB 542a may be any of the sensor configurations described herein or another suitable sensor configuration. In some embodiments, the insertion angle 544 is 90 degrees. As shown in FIG. 4D, in some embodiments, the insertion angle 544 is about 45 degrees, or in some embodiments about 30 degrees, or in some embodiments about 60 degrees, or in some embodiments about 75 degrees, or in some embodiments about 15 degrees, relative to the mixing column flow direction 540. FIG. 5E illustrates a perspective view of a dispenser 560 having a mixing chamber that causes mixing of two or more components before the mixture passes through a PCB sensor 562 and a dispensing nozzle 564.

[0054] As shown in FIG. 4D, the PCB 542 may interact with the sensor housing (e.g., 536) by being guided into position using a slider element inside the mold tool. In some embodiments, the PCB 542 removably slides into position within the dispenser housing. However, in other embodiments, the PCB 542 is sealed in place. This may be advantageous for particularly viscous mixtures that may otherwise push the PCB 542 out of position.

[0055] The exemplary embodiment shown in Figures 4C-4E relates to a PCB-based impedance sensor that can be attached to a static mixer using an adapter or other connection mechanism and provides real-time mix ratio information. The use of an adapter that can accept a PCB unit allows the PCB sensor to be compatible with several dispensing systems.

[0056] Real-time feedback of the mixture moving through the dispensing unit is particularly useful for quality control purposes, especially in operations with frequent starts and stops that can cause the mix ratio to drift over time.

[0057] The PCB sensor is within a housing that can be coupled to a dispenser. However, it is expressly contemplated that the sensor housing and mixing chamber are a single unit in some embodiments. Such a configuration produces a single disposable dispensing unit. This is particularly useful for adhesives such as two-part epoxies that require specific mixing devices and strict adherence to mix ratios. Although not shown in Figures 4C-4E, it is expressly contemplated that a sensing system such as system 530 can include, for example, a temperature sensor mounted on the PCB sensor.

[0058] A single disposable sensor unit simplifies the product as connections between parts are reduced and reduces waste in production as fewer parts are required. Disposable "smart" static mixers can be used with reusable sensor systems such that once the first mixer is disconnected from the sensor system and discarded after the first operation, a second static mixer can be connected to the same sensor system.

[0059] 5 illustrates a method of forming a sensor system according to embodiments herein. Method 600 may be used to form a sensor system such as, for example, sensor system 510 or 400, or another suitable sensor system. Similarly, method 600 may illustrate some ways in which sensor system 400 or 510 may be formed, although it is expressly contemplated that the systems may be manufactured according to other suitable methods.

[0060] At block 610, a template is obtained. The template may have one or more grounds, one or more contact electrodes for receiving commands and communicating signals, and / or other features. As described herein, in some embodiments, a PCB is used. However, while PCBs are inexpensive, it may be preferable to use 3D printing techniques to form the template. In some embodiments, blocks 610 and 620 are performed simultaneously as a 3D printed template is constructed with the conductivity sensor regions in place.

[0061] At block 620, conductivity sensor regions are formed in the template. The conductivity sensor regions may be slots or openings in which positive and negative electrodes may be placed or attached. Each region may have a length 612 and a width 614. The width 614 may be selected based on, for example, the viscosity or particle size present in the material passing through the sensing system. The length 612 may be selected to increase the surface area available for sensing conductivity. There may be a spacing 616 between adjacent conductivity sensor regions. In embodiments where the conductivity sensor regions are slots, the spacing 616 may be dictated in part by the need for structural integrity of the template when under pressure from a viscous material. As shown in block 618, other considerations may also be taken into account.

[0062] The conductivity sensor region may be machined into the template, as indicated in block 622. However, other methods are expressly contemplated, as indicated in block 628.

[0063] At block 630, the electrodes are placed. In some embodiments, the electrodes are placed by a metallization process in which the conductivity sensor area is coated with a metal. This may be a copper coating as shown in block 632, or another metal coating as shown in block 638. The metal coating may be placed, for example, by electroplating, or another suitable connection. However, other electrode placement methods are possible, such as, for example, gluing the electrodes in place.

[0064] At block 640, in some embodiments, the electrodes are separated from each other, such that each conductivity sensor region includes a positive electrode and a negative electrode, and adjacent conductivity sensors are separated from each other. In embodiments where the electrodes are placed by electroplating, it is necessary to remove undesired connections between the positive and negative electrodes. In some embodiments, the conductive portions at the ends of each slot are milled. In some embodiments, the edges are milled further than the edges of the conductive portions. The material exchange is perpendicular to the slots and therefore slower at the ends of each slot. It is preferable to avoid measuring slow moving materials as this can lead to inaccurate measurements.

[0065] 6A-6B show a material measurement flow sensor used in accordance with embodiments herein. As shown in both images, a sensor according to embodiments herein can be placed in direct contact with a material or fluid and provide a conductivity measurement based on that direct contact. This provides a more accurate measurement of the mix ratio than other methods that do not allow for direct contact between the sensor and the material. However, as shown in FIGS. 6A and 6B, the sensor becomes coated with material after use. In scenarios where the material of interest is corrosive, highly viscous, or hardening, it is beneficial to be able to dispose of the sensor after use.

[0066] FIG. 7 illustrates another embodiment of a dispensing system in which embodiments herein may be useful. The system 1000 illustrates a compact dispensing system 1000 with a controller 1002, which may include a motor that provides pressure to dispense fluid through a dispenser 1010. The dispenser 1010 may have entrained air bubbles. In small volumes, the presence of air bubbles can significantly affect the amount of material dispensed by displacing the material with air. For dispensed mixtures, this may result in an inaccurate mix ratio being dispensed. For viscous fluids, this may result in areas of the work surface that do not accept the dispensed fluid.

[0067] It is important to detect and remove air from the dispensing system. Thus, in some embodiments, before reaching the dispensing system 940, the material passes through a sensing area 1020 that includes a PCB-based sensor as described herein. The sensor detects air bubbles and in response a valve 1030 opens to allow the air bubbles to exit through stream 1050. Once the air bubbles have passed, the valve 1030 closes and the material continues to the dispensing system 1040. In some embodiments, there is another sensing area 1020 after the valve 1030 to ensure that the air bubbles have been removed. As shown in FIG. 7, the valve 1030 is located immediately downstream of the sensing system 1020. The valve 1030 opens and closes automatically in some embodiments based on an indication from the sensing system 1020 directly, from the controller 1002, or from another control system that sends commands to automatically purge the material line based on the conductivity measurements received from the system 1020.

[0068] 7 is a schematic diagram of system 1000, with one material line components explicitly shown, however, as illustrated, it is expressly contemplated that a mixture may be formed from two components, and a similar set of components is required to provide a bubble-free second component to a mixing chamber (not explicitly shown).

[0069] FIG. 8 illustrates a method of removing entrained air bubbles from a fluid line according to embodiments herein. Method 1100 may be implemented using a sensor system such as those described herein, or other suitable sensors. At block 1110, air bubbles are detected using a conductivity sensor in contact with the flow material. In some embodiments, the conductivity sensor may be a disposable sensor intended to be discarded after use. The conductivity sensor may include one or more pairs of electrodes in a configuration 1104 on the same plane such that the dispensed material flows through the electrode pairs. Including multiple electrode pairs helps to detect smaller sized air bubbles as they flow through the dispenser. In some embodiments, air bubbles are detected by a discernible conductivity spike 1102. Other dispenser features are also contemplated, as shown in block 1108.

[0070] In block 1120, detected air bubbles are removed from the flowable material. It is important to ensure that the correct volume of material is dispensed, especially for mixtures. A Y-valve 1122 may be used to divert the material flow when air bubbles are detected. In some embodiments, other purging mechanisms 1128 may be used. In some embodiments, it may be possible to mitigate detected air bubbles without purging, for example, by instead sending a signal to a motor that controls the fluid flow to increase the speed and dispense the amount of material needed to replace the volume of air occupied by the air bubbles. However, while the detected spike may be proportional to the size of the air bubble, it is not immediately possible to detect whether the detected air bubble is one large bubble, several smaller bubbles, etc. Additionally, in embodiments where the dispensed fluid must be a certain volume or have a certain shape, it is preferable to remove air bubbles. For example, if the dispensed adhesive must be conductive, air bubbles may cause a breakdown in the conductivity when dispensed.

[0071] The material is dispensed at block 1130. In some embodiments, it is first verified that the material stream is free of air bubbles, as shown in block 1140. This can be done, for example, in some embodiments, using a second conductivity sensor.

[0072] FIG. 9A illustrates a material characterization system in which exemplary embodiments can be implemented. System 1200 is a two-component material dispenser configured to dispense part A component 1202 and part B component 1204. System 1200 can be useful for characterizing mixtures. As each of components A and B is dispensed, they pass through sensing systems 1220, 1230, respectively, as shown in callout 1210, which shows an enlarged view of a portion of dispensing system 1200. Sensing systems 1220, 1230 each include a PCB sensor in a housing 1222 perpendicular to the flow of material, such that the material flows through several slots, each of which includes an electrode pair that measures the electrical conductivity of the material. Housing 1222 can receive PCB sensors that can be replaced periodically in some embodiments. The PCB sensor is in direct contact with component A 1202.

[0073] The sensing system 1220 can be used to validate the material 1202, for example, by comparing actual conductivity values ​​to expected conductivity values. For example, values ​​from a previous lot can be compared to currently sensed values ​​to determine the quality of a new material bath. Thus, lot-to-lot variations can be captured. Additionally, values ​​can be compared run-to-run to detect aging or other factors that may change how component A varies over time. Similarly, the sensing system 1230 can be used to validate the material 1204. The sensing systems 1220, 1230 can be connected to a control system, which can provide an indication to an operator if the sensed conductivity values ​​are outside of an expected range.

[0074] A third sensing system 1240 may be present after the mixer, as shown in callout 1250 showing a second enlarged portion of system 1200. Sensing system 1240 has a PCB sensor in a housing 1242. The conductivity sensor includes multiple slots perpendicular to the flow of the mixed material. Sensing system 1240 may provide several indications, including a mix ratio indication, a cure indication, and other information related to mix quality.

[0075] The figures herein show embodiments in which the sensing systems for the incoming components are separate components (e.g., 1220, 1230 in FIG. 9A), however, it is expressly contemplated that in some embodiments a single sensor that receives both components simultaneously may also be used.

[0076] As shown in FIG. 9B, the housing 1270 can receive material from both part A and part B simultaneously. Each of the openings of the PCB-based sensors herein can be separated from one another, so that a single sensor in 1270 can be used to make conductivity measurements from two different materials. In the illustrated embodiment, a first channel 1272 receives a first component and a second channel 1272 receives a second component. Although only two component channels are shown, it is expressly contemplated that a third channel can receive a third material, and so on. Similarly, while two slots are shown in each channel in FIG. 9B, it is expressly contemplated that in other embodiments there can be more or fewer slots.

[0077] Figure 9C shows a cutaway view of the system of Figure 9B. As shown, channel 1272 receives and provides component A to one or more electrode pairs, through which component A flows. Similarly, channel 1274 receives and provides component B to one or more other electrode pairs on the same PCB sensor. Components A and B flow through housing 1270, with wall 1276 preventing premature mixing.

[0078] FIG. 9D shows another system for material characterization. System 1280 provides a continuous flow of material from holding tanks 1284a,b to a mixer 1286. Pump system 1282a pumps from the first reservoir while filling the second reservoir. When the first reservoir is empty, the valve is reversed so that the first side fills from reservoir 1284a while pump system 1282a pumps material from the second reservoir. Pump system 1282b operates similarly but draws from reservoir 1284b. A spike in conductivity may be detectable whenever pumps 1282a,b change direction.

[0079] The system 1280 may have a temperature sensor and / or a conductivity sensor at the end of the mixer 1286. A continuous flow system such as that shown in FIG. 9D has the advantage that it is a closed system. However, it may be necessary to purge one or both pump systems. Therefore, it is important to capture the pressure from the output side of the bulk dispenser, which can provide additional context for the information captured by one or more PCB sensors described herein.

[0080] In some embodiments herein, a pressure sensor is connected to the exterior of the positive displacement pump. In some embodiments, the pressure signal is captured in amperes. The pressure signal can be converted to a voltage before being provided to an analyzer for analysis. In real time, in some embodiments, the conductivity, temperature, and pressure signals can be captured simultaneously.

[0081] The fluid system signal pressure may be measured in amperes, voltage, or another suitable unit. The ampere measurement may be converted to voltage using, for example, a signal NI box converter or another suitable system. The pressure signal may be provided as a digital signal so that it may be analyzed by an analyzer and used to understand the real-time pressure in the system. However, it is expressly contemplated that other signal units may be used for analysis, for example, without conversion to voltage. The use of current may maintain the fidelity of the signal in the initial measurement. However, it is expressly contemplated that other methods may be used to obtain the pressure signal in situ.

[0082] Several sensor configurations are described herein that may be used with a variety of dispensers, however, it should be noted that modular dispensers may also be used with the sensors herein.

[0083] FIG. 9E shows an exemplary Y-sensor system, which can accept a sensor as described herein, as shown at 1292. Note that the sensor body 1290 is a single component. This makes it difficult to clean. In addition, for small dispensers, the sensor size is relatively large, occupying significant surface area of ​​the channel, resulting in low flow rate. Also, the Y-sensor is difficult to manufacture due to its complex structure.

[0084] 9F shows a modular Y-sensor design that is simpler to manufacture because the four components (top, both sensors, bottom) can be manufactured separately, making it easier to build. Top 1296a accepts the two components from their respective sources and provides them through sensor 1296b before bottom 1296c delivers the components to a mixing chamber. Fasteners 1298 may removably couple components 1296a, 1296b, and 1296c together, making it easier to disassemble them for cleaning.

[0085] Figures 10 and 11 show exemplary conductivity signals that may be received from embodiments herein. The displays of Figures 10-11 may be presented to a user on a display associated with the dispensing system or on a display remote from the sensing system.

[0086] 10A and 10B show conductivity sensor signals that may be presented during optimization or configuration of a dispense process. FIG. 10A shows the mix ratio, conductivity, and temperature measured over time. A series of four dispense operations are shown where different pressures are applied to the A and B components. The first operation is performed at 4x pressure on component A. The second operation is performed at 2x pressure on component A. The third operation 1306 is performed at 2x pressure on component B. A preferred pressure is then set for operation 1308. The preferred pressure is selected to reduce spikes seen in the mix ratio.

[0087] FIG. 10B illustrates a conductivity sensor signal that may be presented when a purge is indicated or automatically initiated. During a dispensing operation, material may be placed in the dispenser. In the case of adhesives or other components that experience hardening or aging, it may be necessary to purge the system to prevent the material from hardening and causing system damage. A purge threshold may be set based on when the material or mixture hardens past a usable point or past a threshold that is safe for the dispensing machine. The threshold may be set by the component manufacturer, a cure profile, or another source. When the sensed conductivity reaches a threshold after an operation, a purge is initiated. For example, one component may be pushed through a mixer until all of the previously mixed components have been flushed through the system. As illustrated, a second purge may be initiated to ensure that the mixture is completely purged, for example, when the purge threshold is reached.

[0088] 11A shows mix quality measurements taken over time. The mix ratio for each of the two-component mixes is varied for each of five different dispense operations. Temperature, conductivity, and standard deviation are measured across a set of electrodes in the sensing system. If the standard deviation is above a high threshold, it may indicate that the mix is ​​not good enough for dispensing. If it is below a low threshold, it may indicate that the mix is ​​good enough. Between the thresholds, the mix ratio may be adjusted.

[0089] FIG. 11B shows the cure progress measured for the mixture. One advantage of the disposable sensor system is its ability to be used to measure cure progress. Dielectric constant, conductivity, and temperature are measured over time for several runs. Cure to maximum exotherm and end of cure can be detected using the sensor system described herein as shown. Pot life may also be measurable.

[0090] 10-11 may be provided by a smart phone or other user device. The GUI may display information about the adhesive being dispensed. Example information may include product name, product color, an image of the product's container such as a tube, lot number and other manufacturing information, and expiration date, among other information.

[0091] 10-11 may display one or more parameters, such as a desired dispense flow rate, in an embodiment, the parameters are editable by a user to allow the user to suggest a desired flow rate, for example, based on the needs of processes downstream of the adhesive process being controlled.

[0092] 12A and 12B illustrate air bubble detection for a material dispensing system according to embodiments herein. FIG. 12A illustrates an exemplary graph of sensed conductivity over time for several sensors. As shown in chart 1500, by measuring conductivity over time, air bubbles can be detected as spikes 1502. The spikes may look different depending on the raw materials, mix ratio, and size of the air bubble. For example, as shown, the spikes may involve a drop in conductivity from a first level to a second level, with the amount of drop varying. Additionally, the time frame to experience the drop may vary. For example, a larger air bubble may take more time to pass through a slot in the PCB sensor and therefore experience a drop over a longer period of time. It should be noted that the data presented in chart 1500 is exemplary only and illustrates qualitative, not quantitative, air bubble detection.

[0093] Therefore, air bubble detection may benefit from using a relative threshold instead of an absolute threshold. It may be important to measure the base level to have a more accurate relative threshold. For example, an air bubble is detected if the conductivity measurement falls below a proportionality factor (e.g., 50% of the base level) relative to the base level. The relative threshold may help reduce material waste due to accidental purging. FIG. 12B shows a system for detecting air bubbles in a material dispensing system. The air detection system 1550 may be implemented by a suitable computing device in communication with a sensing system 1530 associated with the material dispensing system. The sensing system 1530 may include one or more electrode pairs 1532 in direct contact with the material flow. The sensing system 1530 may also include a temperature sensor 1534. The electrode pairs 1532 may be part of a printed circuit board, for example, formed in an opening machined or built into the printed circuit board. The opening may be closed at both ends, for example in a comb-like structure, or open at one end. The temperature sensor 1534 may be shielded from direct contact with the material flow in some embodiments. The sensing system 1532 may include other features 1538.

[0094] The sensor signal from the sensing system 1530 is received by the air detection system 1550 using an active signal acquirer 1552. The active signal acquirer 1552 may receive the signal from the sensing system 1530 periodically or continuously. The received sensor signal may be an impedance signal, a conductivity signal, a permittivity signal, or a combination thereof. In embodiments where conductivity values ​​are used to detect air bubbles, a conductivity signal generator 1554 may convert the received signal to a conductivity value. The signal value and / or the conductivity value may be provided to a data store using, for example, a signal communicator 1556.

[0095] The historical signal acquirer 1558 may communicate with a data store to acquire previously captured signal values. Historical signal values ​​of interest may include signal values ​​acquired in recent time periods from the same batch or mixture of material. For example, values ​​acquired over the previous seconds or minutes may be important. As shown in the chart 1500, the signal values ​​may drift over longer periods due to temperature changes, aging of the material, variations in mix ratios, etc. However, air bubbles are detectable as abrupt changes in conductivity. In some embodiments, the threshold generator 1560 periodically or continuously generates relative thresholds based on the historical signal. The relative thresholds may be absolute values ​​specifying, for example, that an X% increase or decrease over Y time indicates an air bubble. If the conductivity value has fluctuated more significantly, the threshold change value may be larger, and if the conductivity value has not fluctuated significantly, the threshold change value may be smaller.

[0096] The signal analyzer 1562 compares the received signal or the calculated conductivity with a threshold value and if a deviation outside the acceptable threshold is detected, the command generator 1564 generates a command which is communicated to the device 1580 using the command communicator 1566.

[0097] The device 1580, in some embodiments, may include a display component, and the generated command may be an update to a graphical user interface presented on the display component indicating the detected air bubble. The device 1580, in some embodiments, may include a feedback component, such as auditory, visual, or tactile feedback, that indicates to a controller that an air bubble has been detected. The device 1580 may also be a valve controller, and the command generator 1564 may generate a command to purge the flow line in which the air bubble was detected. The device 1580 may also be a motor speed controller, and the controller may generate a new motor speed to compensate for an expected change in the mix ratio based on the air bubble detection.

[0098] The system 1550 may include other features 1568 .

[0099] In some embodiments, the threshold generator includes a machine learning model that predicts the conductivity time series data from historical data into the future. This prediction may include a so-called confidence interval. Training may be done beforehand on a bubble-free reference data set. The signal analyzer 1562 then compares the received signal to determine whether it is within or outside the confidence interval.

[0100] In some embodiments, at regular intervals (e.g., 10 ms, 100 ms, etc.), the threshold generator generates a prediction of the conductivity value using confidence bands based on the historical signals acquired by the historical signal acquirer. If the actual value measured is below the lower confidence band or above the upper confidence band, the signal analyzer detects an air bubble. If the conductivity measurement is within the confidence bands, the signal analyzer 1562 provides an output that no air bubble was detected. The command generator 1564 may provide an indication that the GUI of the device 1580 does not require an update.

[0101] Relative thresholds are an important component of an air detection system due to the noise present in the data. The statistical concept of confidence bands can explain this. If the data is noisy, the confidence band will be far away from the current value and the air bubble detection algorithm will not yield false detections simply due to noisy data; simple thresholding approaches can suffer from this in this case.

[0102] Although electrical conductivity is discussed herein as the value of interest, it is expressly contemplated that other material parameters, such as amount of current and dielectric constant (er), may be used in place of or as well as the detection algorithm.

[0103] So far, a sensor system based on a single PCB substrate has been described. Such systems are relatively inexpensive and therefore cost-effective to use and replace. However, one drawback of the designs described so far is the large stray magnetic field compared to the main magnetic field that exists between each electrode pair. The stray magnetic field effect is caused by the short distance between the input and output of the material flow, e.g., the thickness of the PCB. One way to reduce the stray magnetic field effect is to solder multiple PCBs, each with an opening containing an electrode, to the PCB stack.

[0104] 13A-13F show a sensor stack according to one embodiment of the present invention. As shown, in one embodiment, the sensor stack 2000 may include a four PCB sensor having one four-layer PCB 2010, two stacked PCBs 2020 provided to obtain the required sensitivity by increasing the electrode surface area, and a top PCB 230. Although the embodiment of FIGS. 13A-13F shows a four-layer sensor stack, it is expressly contemplated that fewer or more PCB sensors may be bonded together. For example, as few as two PCBs, or as many as five, six, seven, eight, nine, ten or more PCBs.

[0105] The laminated sensor 2000 offers the advantages of a single PCB sensor with reduced stray field effects. The compact design also improves shielding of the sensing electrodes and allows the sensing area to be internally sealed so that it can be used as an electrode cartridge without the need for additional housing. In some embodiments, the sensing area is internally sealed by soldering and can withstand the pressure applied from the material sensor without the need for additional housing.

[0106] Additionally, the sensor stack 2000 can utilize smaller electrodes, allowing the sensor stack 2000 to be integrated into active or passive mixing nozzles at the material input as well as the material output.

[0107] 13B shows a diagram of the base sensor 2010. The base sensor 2010 is a four-layer PCB and includes an edge connector interface 2050. The base sensor includes transmitting electrodes 2014, each paired with a receiving electrode 2012. The sensor 2010 includes a temperature sensor 2016 sealed within an opening in the PCB 2010 so as not to directly contact the fluid flowing through the sensor stack 2000. In contrast, the electrodes 2012, 2014 directly contact the fluid as it flows through the stack 2000. In embodiments where the sensors 2010, 2020 and 2030 are sealed together, the sensor 2010 may include a seal ring space 2018 that may receive another sealing material, such as a solder or seal ring.

[0108] 13C shows the internal PCB sensor 2020. A connection area 2022 is shown that may accept solder or another adhesive. The internal PCB sensor 2020 may be a two-layer PCB instead of a four-layer PCB, which may allow for cost savings since an additional shielding layer is not needed for the internal sensor 2020. The connection area 2022 may be soldered or encapsulated using another material that allows for a communicative coupling between adjacent sensors 2020, 2030, 2010.

[0109] 13D and 13E show views of the sensor stack from the material input side 2060 and material output side 2070. Fluid flows in the direction indicated by arrows 2062, 2072. Sealing rings 2066, 2076 may be present to seal the PCB sensors to the material flow line. After sealing between all PCB sensors is completed, the sensor stack can be inserted into the material flow by using sealing rings at the sealing points 2066, 2076.

[0110] As shown in Figures 13A-13E, a four channel material impedance sensor is shown with an additional temperature sensor. However, it is expressly contemplated that in some embodiments there may be more or fewer channels. Additionally, in some embodiments, no temperature sensor is provided.

[0111] FIG. 13F illustrates how a stack sensor system such as that shown in FIGs. 13A-13E may be utilized in a material dispensing system. Material dispensing system 2080 may have a mixer 2084 having a stack sensor 2082 at each of the material inlets and a stack sensor 2082 at the mixer outlet. As described with respect to FIGs. 7 and 9, for example, a material dispenser having a sensing system such as that shown in FIG. 13F may enable improved dispensed material characterization, including detection of batch variations in any input material, verification of mix ratios, detection of air bubbles, etc. Although FIG. 13F illustrates a static mixing system, it is expressly contemplated that the embodiments herein are equally applicable to active mixers.

[0112] 14A and 14B show an exemplary batch detail detection for a material dispensing system. As observed in an extensive survey of batches, there may be significant variations in the conductivity of the A and B parts of the mixture. Therefore, it may be helpful or even necessary to perform a calibration measurement each time a new lot of material is introduced. It is desirable to be able to avoid extensive and speculative characterization of the produced material. By using a system such as that of FIG. 7, FIG. 9, or FIG. 13F, three signals can be obtained from each input and output, which can be fused together to produce one measurement. The input and output signals can be corrected for time delay. Each signal has conductivity and permittivity at various frequencies (e.g., 32 Hz to 8 kHz) and a temperature signal at each sensor location position, as shown by graph 2100 of FIG. 14A. This generates a data vector for each sensor location at a time step. This allows the mix ratio to be extracted at various operating conditions as the dispensing operation progresses.

[0113] FIG. 14B illustrates an exemplary model for estimating the mixture ratio based on the received signals from each of the Part A component, the Part B component, and the mixture. In some embodiments, the signal encoder is a pre-trained generative model, e.g., a Variational Autoencoder (VAE) that is trained to encode all signals into a representation and decode the original signal from this representation. However, other models may be suitable. A VAE can ensure that the representation of a signal contains all the information needed to reconstruct it. The encoder receives a signal as input and outputs a representation in the latent space of that signal. The decoder receives a representation as input and outputs a reconstructed signal.

[0114] Next, a machine learning model for estimating the mixture ratio of parts A and B in the mixed material takes as input the three preprocessed and encoded signals from parts A, B, and the mixed material, and outputs the mixture ratio in the mixed material.

[0115] The signal encoder and regressor may operate locally, for example using a computer processing device associated with the material dispensing system. Alternatively, either the encoder or regressor, or both, may be deployed in a cloud-based storage system.

[0116] The output of the encoder may be used directly to apply pressure changes to cartridges associated with components A and B to ensure the mixture meets a predetermined mix ratio. For example, if the mixed material contains too much part A, the pressure on the cartridge containing part A is reduced and the pressure on the cartridge containing part B is increased.

[0117] A regressor may then take the encoded signals and generate a mixture signal. The regressor may be a machine learning based algorithm that may be trained in any suitable manner.

[0118] The first training option is a separate training option where an encoder-decoder model is trained on a set of signals of part A, part B, and various parts for various mixtures. Machine learning regressors are then trained in a second step on the encoded signals and the corresponding mixture ratios.

[0119] The second training option is the alternating training option, where one batch of signals is used for one training step in the encoder-decoder and then for one training step in the encoder-machine learning regressor part. The training step consists of a forward pass over the data in the batch, computing gradients, and applying the gradients to optimize the weights in the model.

[0120] The third training option is the combined training option, where the triplet of the encoder-decoder pair and the machine learning model are optimized simultaneously. This means that the batch is passed through the encoder, and the resulting representation is passed through the decoder and the machine learning regressor. Then the gradients calculated with both outputs are applied in a weighted combination in the backward pass.

[0121] Alternating or combined training may provide the advantage that signal representations are learned that have a positive effect on the performance of the regressors that can result in lower errors when estimating mixture ratios. Also, learning signal representations for a variety of materials and mixture ratios allows the model to be used for previously unseen materials of the same chemical family.

[0122] Unlike systems that use only a single signal from a mixed material, this novel approach allows adaptation to lot-to-lot variations of raw materials, where a change in one of the parts may result in a change in the mixed signal for the same mix ratio. It also allows tracking the mix ratio of new materials of the same family to learn to fuse the signals of the two parts into a mixed signal. In addition, data traces collected from the sensor system can be processed to provide information other than just the mix ratio. As described herein, in some embodiments, the sensor includes four electrode pairs. A time series of conductivity can be analyzed from the four sensor capacitors. σ i (t),i∈{1,2,3,4} Equation 1

[0123] For example, incomplete mixing due to using a static mixer that is too short will show up in the sensor output as high variability. The variability can be quantified by calculating the variance over a time window, e.g., 10 seconds. The time window can vary based on the speed of the process and the mixer throughput.

number

number

[0124] Mixing may also take time to reach a steady state. For example, when starting the mixing operation, back pressure and different viscosities of the components may cause the mix to start poorly and gradually stabilize. The same dispersion can be used to track stabilization and indicate when the dispenser is ready to dispense material onto the work piece or into a receiving vessel. The trend of dispersion can be analyzed using Equation 4. V i (t)-V i (t-Δt) <V thresh formula 4

[0125] Threshold V thresh is specific to each material. Instead of determining a threshold, the signal can be tested for stationarity using the extended Dickey-Fuller test. The advantage of this is that the ADF test is adaptive, whereas manual thresholds often need to be adjusted for new batches.

[0126] Inhomogeneity can also be detected using the sensors described herein. The four electrode pairs should also record similar readings. Some constant offsets may occur due to manufacturing tolerances, but in a stable mixing process, the variations of the four signals should be synchronous. To check this, calculate the covariance of the signals without time shift.

number

[0127] Once the signals have stabilized, the four sensors should have high covariance. Negative covariance indicates persistent anti-correlated behavior, implying spatial inhomogeneity.

[0128] Similarly, a single component of a 2K adhesive may also become inhomogeneous, for example due to settling in the barrel or insufficient mixing during production. To check constancy over time, the extended Dickey-Fuller test can again be used. The relevant time frame is determined by the time it takes to empty the container.

[0129] 15 illustrates a method for controlling a material dispensing system according to embodiments herein. The method 700 may be used with a dispenser described herein or another suitable sensing system.

[0130] At block 810, one or more components to be dispensed are provided to the dispenser. For example, the dispenser may dispense a liquid 812, particles 814, either in suspension or other state. The material may also be a mixture of materials 816. For example, an adhesive may be formed from an A component and a B component provided in a desired mixing ratio. Other components 818 may also be provided to the dispenser for dispensing.

[0131] At block 820, the material is passed through a sensing system before being dispensed onto the work surface. Passing through the sensing system may include passing through a portion of the sensor body such that the material directly contacts the sensor. In a conductivity sensor, direct contact between the material and the electrode pair ensures accurate measurements.

[0132] At block 830, the conductivity measurements are received from a sensing system. The sensing system may have multiple sensors, e.g., multiple electrode pairs that detect the conductivity of the material when a sufficient voltage is passed through. Based on the conductivity readings, several things can be determined about the material. For mixtures, the mix ratio can be determined. For curable materials, the curing progress can be detected. Aging can also be detected, as can differences between batches of material. Entrapped air can also be detected. The conductivity measurements can be made continuously, e.g., one signal is received every second, or more frequently. The conductivity measurements can be made in parallel, e.g., from each of multiple electrode pairs. In some embodiments, the electrode pairs can be coplanar with each other.

[0133] At block 840, feedback is provided based on the conductivity measurements. The feedback may include a characterization of the material, as shown in block 832. For example, the mix ratio may be detected, or an indication of entrained air or aging may be provided. Predictions may also be made, as shown in block 834. For example, based on trends in previous conductivity sensor readings, it may be possible to predict future behavior. A conductivity reading going in one direction may indicate that the mix ratio is moving toward the edge of the acceptable range, and therefore the mix ratio should be changed, as shown in block 842. Similarly, the conductivity reading may indicate that a hardenable component is beginning to harden. Thus, feedback may indicate that a purge of a component, components, or mixture is required, as shown in block 844. In embodiments where the material has a corrosive effect or hardens over time, predictive feedback may provide an indication that the sensor needs to be replaced, as shown in block 846. Other predictive information may be provided, as shown in block 838, or other actions may be triggered, as shown in block 848.

[0134] In some embodiments, as described herein, providing feedback may also include providing conductivity readings, material characterization, or predictions to a customer, a dispenser controller, or other useful information such as material source, batch number, material name, dispense temperature, dispense pressure, material concentration(s), mix ratio, or any other information.

[0135] 16 illustrates a material dispensing system according to embodiments herein. The system 900 may include a dispenser 910 having one or more cartridges 912 that contain the material to be dispensed. The cartridges 912 may dispense the material at a rate based in part on the speed of a corresponding motor 914. A dispenser controller 916 may provide control signals to the motors 914 to drive the flow of material from each cartridge 912 by increasing or decreasing the speed of the corresponding motor(s) 914. The dispenser 910 may have other features 918, such as heating or cooling elements, if the material is to be dispensed at an elevated temperature or if heat needs to be provided or removed from an exothermic or endothermic reaction of reactive components.

[0136] The dispensing system 900 may also include a sensing system 920 having one or more conductivity sensors 922 disposed on a PCB board 924. The PCB board 924 may include one or more ground planes, one or more contacts for connecting to a system controller 930 or a power supply 940 or another power source. The sensors 922 may be coplanar on the PCB 924 or may be formed in slots in the PCB 924, for example, by either metallization or another process. The sensors 922 may be isolated from one another such that an independent conductivity signal is received from each sensor. The sensors 922 may each include a positive electrode and a negative electrode that are isolated from one another.

[0137] The controller 930 may receive sensor signals from the sensing system 920 using a signal receiver 932. The signals may be received as a conductivity signal or a permittivity signal, but also as an impedance signal. In an embodiment where the received signal is an impedance signal, a conductivity calculator 933 may calculate a conductivity value based on the impedance signal. Similarly, a permittivity calculator 935 may calculate a permittivity value based on the impedance signal. Based on the received sensor signals, the controller 930 may trigger several calculations and / or predictions. For example, a mixing analyzer 934 may calculate a mixing ratio of the mixture of components to be dispensed. The mixing ratio 934 may be calculated based on calibration data 982 stored in a data store 980, which may indicate conductivity data from pure components and / or known mixtures of components. As mentioned above, sensors may be located at both the inlet and outlet of the mixer, and thus the mixing analyzer 934 may receive sensor signals from all sensors associated with the material dispensing system. The mixing analyzer 934 may compensate for time delays between the sensors.

[0138] The cure analyzer 936 may also detect cure occurrence and cure progression based on the conductivity signal. For example, if cure significantly progresses, the purge trigger 942 may need to trigger a purge of one or more components or mixture of components. Similarly, an indication may be provided that the PCB 924 should be replaced based on cure that may damage or render the sensor 922 inaccurate. Based on a comparison of the calibration data 982 or contemporaneous conductivity signal to historical data from the system 900 or another system, the aging analyzer 938 may detect aging of one or more components or mixture and provide an indication as to whether the material should be discarded. It is also possible to detect entrained air using the entrained air detector 939 based on the conductivity sensor signal. These and other parameters 948 may also be detectable.

[0139] The controller 930 may also be able to analyze trends using the signal trend analyzer 944 using historical data 984 from current or past dispense operations. Curing may begin any time a dispense is not occurring and material is in the dispenser, for example during a flow cycle. Similarly, it may be possible to detect that a purge may end, for example, if the conductivity is less than about 6 or about 5.5. Curing progress may be explicitly tracked to verify that curing is progressing as expected. Curing may have some volume dependency, but the sensor system 920 may provide an indication that the material meets specifications based on the curing profile.

[0140] The controller 930 may also be capable of detecting changes in composition over time based on the sensor signal using a composition drift analyzer 937. The controller 930 may also be capable of determining whether the input material is homogeneous as it enters the mixer using a homogeneity analyzer 943.

[0141] During start-up, the controller 930 may have the start-up analyzer 941 monitor the incoming material stream and the mixer output to determine when the mixing process has stabilized.

[0142] The controller 930 may also be in communicative contact with other devices such that the command generator 942 may generate device commands and the command communicator 944 may communicate the device commands. For example, if the mix analyzer 934 detects that the mix ratio is off, a motor signal may be generated by the command generator to adjust the speed of the motor 914 before the mix ratio exceeds or falls below an acceptable threshold. Similarly, a purge of the cartridge 912 may be triggered or terminated by the command generator 942 based on the hardening or aging of the material detected using the cure analyzer 936. For example, for a given material, it may be known that if the conductivity increases by another X%, the material will no longer be dispenseable and a purge may be triggered.

[0143] Other information 988 may be stored in a data store 980 and accessible by the controller 930 for analysis and operational improvement of the dispenser 910 or sensing system 920. For example, material information 987 may be stored in the data store 980. The data store 980 may be local to the controller 930 or may be accessible via a cloud-based network. Similarly, although the controller 930 is shown in FIG. 16 as being local to the dispensing system 930, it is expressly contemplated that the controller 930 may be remote from the material dispensing system and may receive signals and send commands using a wireless-based or cloud-based network.

[0144] The GUI generator 950 may generate a graphical user interface for display on the display component 960 based on some or all of the information collected or generated by the controller 930. For example, conductivity sensor data may be presented. Calculated mix ratios may also be presented, as well as dispense parameters including target mix ratios, motor speeds, pressures, temperatures, etc.

[0145] Another component that the dispenser 910 may have is a mixing element, which may have one or more mixing elements. To reduce the complexity and associated costs of the dispenser 910, it is desirable to have the fewest mixing elements possible. Similarly, the larger the internal surface area within the dispenser, the more material must be wasted or purged at the end of the operating time. In some embodiments, mixing may be considered sufficient if the standard deviation between several coplanar conductivity sensors is less than 0.1. If the conductivity of the material varies more than the conductivity across the sensing surface, the mixing element may need to be extended. For new adhesives or mixtures, the sensing system herein may be useful to design a suitable static mixer. For active mixers, the sensors herein may be useful to sense and adjust the rotation speech until the material mixture is satisfactory.

[0146] Systems and methods utilizing machine learning algorithms are described herein. Machine learning models may be preferred because they can handle noisy data better, make predictions about future signal trends, and make adjustments before the mix quality shifts significantly. The systems and methods described herein can calculate the mix ratio in real time. Using machine learning techniques, the mix ratio can be predicted in advance. This allows for faster adjustments and keeps the mix ratio closer to the target value more of the time. In some current dispensers, many materials get mixed into the static mixer, so that by the time a shift in the mix ratio is detected, the materials already in the mixer will continue to have the wrong mix ratio for at least the adhesive equivalent of the mixer, and therefore identifying the mix ratio problem earlier can save material and potential purging.

[0147] Similarly, the machine learning model may receive information from multiple systems, such as multiple sensors in a dispensing system, including conductivity sensors, temperature sensors, motor speed signals, material information, etc., as described herein. In some embodiments, multiple machine learning models are used simultaneously by each individual system, such that the model for each system can learn and the overall model can be improved. However, it is expressly contemplated that non-machine learning models may also be used.

[0148] Controller 930 is described as having the ability to transmit and receive communicative information to other devices. This may be done, for example, through an application program interface such that controller 930 can receive and communicate with pump controllers, line pressure sensors, motion controllers for portions of the dispensing system, temperature sensors, heating elements, data stores having information regarding either the materials dispensed or the mixtures produced, etc.

[0149] In embodiments where machine learning models are used, the data store may also include an analyzer that learns the usage behavior of a particular dispensing system to improve operation and predictions. Similarly, dispensing frequency and patterns may provide information about curing and improve the mixing model. For example, usage data such as dispense frequency, purge frequency, dispense pattern, sensor replacement, etc. may be collected and used to allow the model to learn about adhesive curing. This additional data may be included in the characterization of the adhesive to improve the predictive power of the model built based on the sensor data. Curing depends on many factors including the length, width, and other geometry of the static mixer, the exothermic properties of the adhesive, reaction rate, downstream fittings such as tubing or tips, time, and other factors. Knowing the reaction rate of the adhesive itself is not enough. With this amount of complexity, collecting usage data and training machine learning models is the best way to enable higher quality predictions, which allows for higher quality feedback and control over the process.

[0150] In embodiments where inventory information is also stored in data store 980 or otherwise accessible by controller 930, controller 930 may indicate that inventory is low or may order material based on low inventory.

[0151] Similarly, as described herein, the display 960 may display a GUI created by the generator 950 that is periodically updated with information to which the controller 930 has access, such as any sensor data received, any analysis results generated by the analyzers 934, 936, 938, 939, 937, 941, 943, any information obtained from the data store 980, etc. The information may be updated passively, or a warning or notification may be provided as it is updated, e.g., if the mix ratio is drifting towards an unacceptable range, current status information may be presented and a warning (visual, audible, or tactile) may be provided. Additionally or alternatively, a notification may be provided when a device command is generated or when operator intervention is required. For example, in an embodiment in which the command generator 942 cannot communicate with another device, the command communicator 944 may send a message to the display 960, a speaker, or another notification device to indicate to the operator that a purge is needed, that a motor speed needs to be changed, that the temperature is too high or too low, etc.

[0152] In some embodiments herein, it is envisioned that the controller 930 may use the command generator 942 to generate commands to maintain the mixture output within the desired parameter range, such as, for example, purging detected air bubbles, adjusting motor speed to maintain the mix ratio, increasing or decreasing heating elements to maintain the desired viscosity, etc. Fine adjustments may be made automatically. However, there may be cases where the controller 930 is unable to maintain the desired mixture output using fine adjustments (e.g., the presence of air bubbles, blocked lines, or material spillage, etc.). The controller 930 may be able to address air bubbles as described herein. The controller 930 may also be able to detect blockages or low material based on the historical behavior of the dispensing system 900. In situations where the controller 930 is unable to maintain the desired mixture parameters, it may trigger an alarm, notification, or otherwise indicate that the mixture provided is not as per specification.

[0153] FIG. 17A illustrates a concentration profile simulation system architecture. Architecture 1600 illustrates one embodiment of an implementation of a conductivity sensing system 1610. As an example, architecture 1600 can provide computation, software, data access, and storage services that do not require end-user knowledge of the physical location or configuration of the system delivering the services. In various embodiments, the remote server can deliver the services over a wide area network, such as the Internet, using an appropriate protocol. For example, the remote server can deliver applications over a wide area network, which can be accessed through a web browser or any other computing component. The software or components shown or described in FIGS. 1-16 and corresponding data can be stored on a server at a remote location. Computing resources in a remote server environment can be aggregated at a remote data center location, or they can be distributed. The remote server infrastructure can deliver services through shared data centers, which appear as a single access point to users. Thus, the components and functions described herein can be provided from a remote server at a remote location using a remote server architecture. Alternatively, they may be provided by a traditional server, installed directly on the client device, or provided in other manners.

[0154] In the example shown in FIG. 17, some items are similar to those shown in the previous figures. FIG. 17 specifically illustrates that the conductivity sensing system 1610 can be located at a remote server location 1602. Thus, the computing device 1620 accesses those systems through the remote server location 1602. The user 1650 can also access the user interface 1622 using the computing device 1620. For example, the user 1650 may be a user sitting in a parking lot who wants to check the fit of a respiratory protective device while interacting with an application on the user interface 1622 of a smartphone 1620, laptop 1620, or other computing device 1620.

[0155] FIG. 17 illustrates that it is contemplated that some elements of the system described herein are located at the remote server location 1602 while others are not. As an example, data stores 1630, 1640, and / or 1660 can be located at a location separate from location 1602 and accessed via a remote server at location 1602. Regardless of where they are located, they can be accessed directly by computing device 1620 over a network (either a wide area network or a local area network), hosted at a remote site by a service, offered as a service, or accessed by a connection service present at a remote location. Data can also be stored virtually anywhere and accessed or transferred to a party intermittently. For example, a physical carrier can be used instead of or in addition to an electromagnetic carrier. This can enable a user 1650 to interact with the system 1610 via his / her computing device 1660 to initiate a seal check process.

[0156] It should also be noted that elements of the systems described herein, or portions thereof, can be located on a wide variety of different devices, including, but not limited to, servers, desktop computers, laptop computers, embedded computers, industrial controllers, tablet computers, or other mobile devices, such as palmtop computers, cell phones, smartphones, multimedia players, personal digital assistants, and the like.

[0157] FIG. 17B illustrates an exemplary system architecture. In the embodiment of FIG. 17B, the system is wired and is therefore not a wireless or open dispensing solution. Wired communication may also be preferred in embodiments where a wireless connection has slower transfer speeds or potential unreliability. However, it is contemplated that a wireless system may also be possible, as discussed with respect to FIG. 17A.

[0158] The conductivity sensor 1680 may, for example, capture a conductivity signal from one or more PCB sensors described herein and provide the sensor signal to a signal converter 1682, where signal conversion occurs, if necessary. However, it is expressly contemplated that in some embodiments the conductivity sensor 1680 may provide the sensor signal directly to the processor 1684. The signal converter 1682 may, for example, convert impedance to conductivity, analog signals to digital signals, or perform another suitable conversion.

[0159] The processor 1684 receives the conductivity indication and generates a conductivity output, which may be provided to one or more devices 1686. The device 1686 may include a computing device with a display, a smartphone with a display, a laptop with a display, or another device, such as a storage medium that stores the conductivity sensor signal for future reference. The processor 1684 may also reference one or more data stores 1688 to generate additional indications. For example, the data stores 1688 may include past conductivity sensor signals, conductivity sensor signal thresholds, commands to adjust dispense parameters based on the conductivity signal thresholds, etc. The processor 1684 may act accordingly.

[0160] According to embodiments herein, the system may also have a pressure sensor 1690 that generates a pressure signal indicative of the pressure detected at a point in the dispensing system. If necessary, a signal converter 1692 may convert the pressure signal from one form to another, from amperes to voltage, analog to digital, etc.

[0161] Processor 1684, or another suitable processor, generates a pressure output, which may be provided to one or more devices 1686. Processor 1684 may receive signals from pressure sensor 1690 and conductivity sensor 1680 continuously throughout the process and may also generate outputs continuously to provide substantially real-time information about the dispensing system. Processor 1684 may include one or more suitable machine learning techniques, may reference lookup tables, or may perform another suitable data analysis technique on the received conductivity or pressure signals.

[0162] The processor 1684 may communicate with the sensors 1680, 1690 wirelessly, using a wired connection, or over any other suitable network. The processor 1684 may receive signals as encrypted signals, provide outputs as encrypted outputs, or operate without an encryption protocol in place.

[0163] In some embodiments, a data broker (such as an MQTT broker) is used so that the receiving or transmitting device can control what data is transmitted. For example, a site manager may be responsible for lines 1-3 and therefore does not need to receive data from lines 4-6. The site manager may only want to review status information (e.g., detected mixture drift) and is not interested in a graphical user interface that graphically displays the current flow measurements.

[0164] In some embodiments, the processor 1684 also communicates with a data store 1688 such that the conductivity and pressure signals are also stored for later analysis. For example, a data set including the conductivity and pressure signals over time may be used to train a machine learning algorithm or may be used for troubleshooting purposes. For example, the machine learning algorithm may detect patterns in the data set, such as an off mix ratio and the need for purging, and may provide an indication and / or threshold as to how to detect when a mix ratio deviation occurs before it becomes severe.

[0165] Figure 17B shows a single processor receiving information from a single set of sensors for a dispensing operation. However, it is expressly contemplated that a production environment may have multiple dispensers operating with multiple conductivity and pressure sensors providing status information continuously. Thus, it is anticipated that multiple users may wish to view information regarding multiple production lines simultaneously. Figure 17C shows one configuration of a system that may be capable of providing such functionality.

[0166] FIG. 17C illustrates a signal analysis system 2100 that communicates with several devices using a cloud-based network. As shown in FIG. 7C, the signal analysis system 2100 can communicate with a local analysis system 2140 as described in relation to FIG. 17B. The signal analysis system 2100 can receive several sensor signal data 2110 from several dispensing operations, such as pilot line 2104, any of the operating lines 2102, and / or laboratory setup 2106. As described in relation to FIG. 17B, the sensor signal 2100 can be a digital signal, an analog signal, a conductivity measurement signal, a pressure signal, or other signal information. For example, a low reservoir detection signal, a valve switch indication, or any other detectable indication from any of the systems 2102-2106.

[0167] The signal analysis system 2100 may perform analysis on the received sensor signal information 2100 using any suitable analysis tools, such as, for example, lookup tables, comparison thresholds, and / or machine learning algorithms, to detect parameter trend information that may indicate a problem or action that needs to be taken, such as purging or adjusting the mix ratio.

[0168] The signal analysis of 2100 may provide an output display 2120 of some suitable device 2150. The signal analysis system 2100 may provide the output information 2120 continuously, or may provide the information in response to a request 2130. Alternatively, the request 2130 may be a one-time request for current status information, or a request to receive ongoing, continuous updates.

[0169] 18-20 illustrate an exemplary device that may be used in the embodiments shown in the preceding figures. FIG. 18 illustrates an exemplary mobile device that may be used in the embodiments shown in the preceding figures. FIG. 18 is a simplified block diagram of one illustrative example of a handheld or mobile computing device that may be used as either a worker's device or an administrator / safety officer device, for example, in which the system of the present application (or a portion thereof) may be deployed. For example, the mobile device may be deployed within an operator compartment of a computing device for use in generating, processing, or displaying data.

[0170] 18 provides a general block diagram of components of a mobile cellular device 1716 that may execute some of the components shown and described herein. The mobile cellular device 1716 executes and interacts with some of the components. The device 1716 is provided with a communication link 1713 that allows the handheld device to communicate with other computing devices and under some embodiments provides a channel for automatically receiving information, such as by scanning. Examples of communication link 1713 include wireless services used to provide cellular access to a network, as well as enabling communication via one or more communication protocols, such as protocols providing local wireless connectivity to a network.

[0171] In another example, the application may be received on a removable Secure Digital (SD) card that is connected to the interface 1715. The interface 1715 and communication link 1713 communicate with a processor 1717 (which may also embody a processor) along a bus that is also connected to memory 1721 and input / output (I / O) components 1723, as well as a clock 1725 and a position information system 1727.

[0172] I / O components 1723, in one embodiment, are provided to facilitate input and output operations and device 1716 may include input components such as buttons, touch sensors, optical sensors, microphones, touch screens, proximity sensors, accelerometers, orientation sensors, etc., and output components such as display devices, speakers, and / or printer ports. Other I / O components 1723 may be used as well.

[0173] Clock 1725 illustratively comprises a real-time clock component that outputs the time and date, and may also provide timing functions for processor 1717.

[0174] Illustratively, location information system 1727 includes components that output the current geographic location of device 1716. This may include, for example, a global positioning system (GPS) receiver, a LORAN system, a dead reckoning system, a cellular triangulation system, or other positioning systems. It may also include, for example, mapping or navigation software that generates desired maps, navigation routes, and other geographic features.

[0175] The memory 1721 stores an operating system 1729, network settings 1731, applications 1733, application configuration settings 1735, data store 1737, communication drivers 1739, and communication configuration settings 1741. The memory 1721 can include all types of tangible, volatile and non-volatile computer readable memory devices. It can also include computer storage media (discussed below). The memory 1721 stores computer readable instructions that, when executed by the processor 1717, cause the processor to perform computer-implemented steps or functions in accordance with the instructions. The processor 1717 can also be activated by other components to facilitate their functions. Although the physical memory store 1721 is shown as part of the device, it is expressly contemplated that cloud computing options are available where some data and / or processing is performed using remote services.

[0176] 19 shows that the device may also be a smartphone 1871. The smartphone 1871 has a touch-sensitive display 1873 that displays icons or tiles or other user input mechanisms 1875. The mechanisms 1875 can be used by a user to run applications, make calls, perform data transfer operations, etc. Generally, smartphones 1871 are built on a mobile operating system and offer greater computing power and connectivity than feature phones. It should be noted that other forms of devices are possible.

[0177] However, although FIG. 19 shows an embodiment in which the device 1800 is a smartphone 1871, it is expressly contemplated that the display may be presented on another computing device.

[0178] FIG. 20 is an example of a computing environment in which elements of the systems and methods described herein, or portions thereof (for example), can be deployed. Referring to FIG. 20, an exemplary system for implementing some embodiments includes a general-purpose computing device in the form of a computer 1910. Components of the computer 1910 may include, but are not limited to, a processing unit 1920 (which may include a processor), a system memory 1930, and a system bus 1921 that couples various system components, including the system memory, to the processing unit 1920. The system bus 1921 may be any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, and a local bus, using any of a variety of bus architectures. The memory and programs described with respect to the systems and methods described herein may be deployed in the corresponding portions of FIG. 20.

[0179] The computer 1910 typically includes a variety of computer readable media. Computer readable media may be any available media that can be accessed by the computer 1910, including both volatile and nonvolatile media, and removable and non-removable media. By way of example, and not limitation, computer readable media may include computer storage media and communication media. Computer storage media is distinct from and does not include modulated data signals or carrier waves. Computer storage media includes hardware storage media, including both volatile and nonvolatile, removable and non-removable media, implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory, or other memory technology, CD-ROM, digital versatile disk (DVD), or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage, or other magnetic storage devices, or any other medium that can be used to store the desired information and that can be accessed by the computer 1910. Communication media may embody computer readable instructions, data structures, program modules or other data in a transport mechanism and include any information delivery media. The term "modulated data signal" means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal.

[0180] The system memory 1930 includes computer storage media in the form of volatile and / or nonvolatile memory such as read only memory (ROM) 1931 and random access memory (RAM) 1932. A basic input / output system (BIOS) 1933, containing the basic routines that help to transfer information between elements within the computer 1710, such as during start-up, is typically stored in ROM 1931. RAM 1932 typically contains data and / or program modules that are immediately accessible to and / or presently being operated on by the processing unit 1920. By way of example, and not limitation, FIG. 19 illustrates operating system 1934, application programs 1935, other program modules 1936, and program data 1937.

[0181] The computer 1910 may also include other removable / non-removable, volatile / non-volatile computer storage media. By way of example only, Figure 20 illustrates a hard disk drive 1941, a non-volatile magnetic disk 1952, an optical disk drive 1955, and a non-volatile optical disk 1956, which read from or write to non-removable, non-volatile magnetic media. The hard disk drive 1941 is typically connected to the system bus 1921 through a non-removable memory interface, such as interface 1940, and the optical disk drive 1955 is typically connected to the system bus 1921 by a removable memory interface, such as interface 1950.

[0182] Alternatively, or in addition, the functions described herein may be performed, at least in part, by one or more hardware logic components, such as, but not limited to, Field-programmable Gate Arrays (FPGAs), Application-specific Integrated Circuits (ASICs), Application-specific Standard Products (ASSPs), System-on-a-chip systems (SOCs), Complex Programmable Logic Devices (CPLDs), and the like.

[0183] The drives and their associated computer storage media discussed above and illustrated in Figure 20 provide storage of computer readable instructions, data structures, program modules and other data for the computer 1910. In Figure 20, for example, hard disk drive 1941 is illustrated as storing operating system 1944, application programs 1945, other program modules 1946, and program data 1947. Note that these components can either be the same as or different from operating system 1934, application programs 1935, other program modules 1936, and program data 1937.

[0184] A user may enter commands and information into the computer 1910 through input devices such as a keyboard 1962, a microphone 1963, and a pointing device 1961, such as a mouse, trackball, or touch pad. Other input devices (not shown) may include a joystick, game pad, satellite receiver, scanner, or the like. These and other input devices are connected to the processing unit 1920 through a user input interface 1960 that is often coupled to the system bus, although they may be connected by other interface and bus structures. A visual display 1991 or other type of display device is also connected to the system bus 1921 via an interface, such as a video interface 1990. In addition to the monitor, computers may also include other peripheral output devices, such as speakers 1997 and printer 1996, which may be connected through an output peripheral interface 1995.

[0185] The computer 1910 operates in a networked environment using logical connections, such as a Local Area Network (LAN) or a Wide Area Network (WAN), to one or more remote computers, such as a remote computer 1980.

[0186] When used in a LAN networking environment, the computer 1910 is connected to the LAN 1971 through a network interface or adapter 1970. When used in a WAN networking environment, the computer 1910 typically includes a modem 1972 or other means for establishing communications over the WAN 1973, such as the Internet. In a networked environment, program modules may be stored in remote memory storage devices. Figure 20 illustrates, for example, that remote application programs 1985 may reside on the remote computer 1980.

[0187] In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings, which illustrate specific embodiments in which the invention may be practiced. The illustrated embodiments are not intended to be exhaustive of all embodiments in accordance with the present invention. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

[0188] Unless otherwise indicated, all numbers expressing size, quantities and physical characteristics of features used in the specification and claims are to be understood as being modified in all instances by the term "about." Accordingly, unless specifically indicated to the contrary, the numerical parameters set forth in the above specification and appended claims are approximations that may vary depending upon the desired properties one of ordinary skill in the art would seek to obtain using the teachings disclosed herein.

[0189] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include embodiments having plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is used in its general sense including "and / or" unless the content clearly dictates otherwise.

[0190] Spatial terms, including but not limited to "proximal," "distal," "lower," "upper," "below," "lower," "upper," and "above," are utilized as used herein to facilitate description of describing the spatial relationship of one element or elements to another element. Such spatial terms encompass various orientations of the device in use or operation in addition to the specific orientations illustrated and described herein. For example, if an object shown in the drawings is inverted or turned over, portions previously described as below or beneath other elements would therefore become above or above those other elements.

[0191] As used herein, when an element, component, or layer is described as being "on", "connected", "coupled", "stacked" or "in contact with", e.g., forming a "coincident interface" with, another element, component, or layer, the element, component, or layer may be, e.g., directly on, directly connected to, directly coupled with, directly stacked on, or in direct contact with the particular element, component, or layer, or intervening elements, components, or layers may be on, connected to, coupled with, or in contact with the particular element, component, or layer. For example, when an element, component, or layer is referred to as being "directly on", "directly connected to", "directly coupled" or "in direct contact with" another element, there are no intervening elements, components, or layers, for example. The techniques of this disclosure may be implemented in a wide variety of computing devices, such as servers, laptop computers, desktop computers, notebook computers, tablet computers, handheld computers, smartphones, and the like. Although any components, modules, or units have been described to emphasize functional aspects, implementation by various hardware units is not necessarily required. Furthermore, the techniques described herein may be implemented by hardware, software, firmware, or any combination thereof. Any features described as modules, units, or components may be implemented together in an integrated logic device, or separately as separate but interoperable logic devices. In some cases, various features may be implemented as an integrated circuit device, such as an integrated circuit chip or chipset. Additionally, although several separate modules, many of which perform unique functions, have been described throughout this specification, the overall functionality of all of the modules may be combined into a single module or split into further additional modules. The modules described herein are merely exemplary and are described to facilitate easier understanding.

[0192] When implemented in software, the technique may be realized at least in part by a computer-readable medium including instructions that, when executed by a processor, perform one or more of the methods described above. The computer-readable medium may include a tangible computer-readable storage medium and may form part of a computer program product, which may include packaging materials. The computer-readable storage medium may include random access memory (RAM), such as synchronous dynamic random access memory (SDRAM), read-only memory (ROM), non-volatile random access memory (NVRAM), electrically erasable programmable read-only memory (EEPROM), flash memory, magnetic or optical data storage media, and the like. The computer-readable storage medium may also include non-volatile storage devices, such as hard disks, magnetic tapes, compact disks (CDs), digital versatile disks (DVDs), Blu-ray disks, holographic data storage media, or other non-volatile storage devices.

[0193] The term "processor" as used herein may refer to any of the aforementioned structures, or any other structure suitable for implementing the techniques described herein. In addition, in some aspects, the functions described herein may be provided in dedicated software or hardware modules configured to execute the techniques of the present disclosure. Even when implemented in software, the techniques may use hardware, such as a processor that executes the software, or memory that stores the software. In such cases, a computer as described herein may define a particular machine capable of executing a particular function as described herein. The techniques may also be implemented entirely in one or more circuits or logic elements that may be considered a processor.

[0194] An electrical property sensor is presented that includes a printed circuit board having a first side separated from a second side by a thickness, the first side having a length and a width. The sensor also includes an opening extending from the first side of the printed circuit board to the second side of the printed circuit board. The opening includes a receiving electrode and a transmitting electrode. When a fluid flows through the opening and a voltage is supplied to the transmitting electrode, a current is measured at the receiving electrode.

[0195] The sensor may be implemented such that the electrical current can be converted into a value of an electrical property of the fluid.

[0196] The sensor may be implemented such that the electrical characteristic includes an impedance value, a conductivity value, or a permittivity signal.

[0197] The sensor may be implemented such that the opening is parallel to the length and perpendicular to the width.

[0198] The sensor may be implemented such that the opening is at an angle relative to its length.

[0199] The sensor may be mounted such that the printed circuit board is oriented perpendicular to the fluid flow.

[0200] The sensor may be implemented such that the receive and transmit electrodes each have an electrode width that is substantially the thickness.

[0201] The sensor may be implemented such that the receiving and transmitting electrodes each have an electrode length that is less than the aperture length.

[0202] The sensor may be implemented such that the receiving electrode comprises a metal.

[0203] The sensor may be implemented such that the transmitting electrode also comprises metal.

[0204] The sensor may be implemented such that the metal comprises copper, aluminum, gold, silver, or a combination thereof.

[0205] The sensor may be implemented to further include a gold coating over the copper.

[0206] The sensor may be implemented such that the opening is a first opening, and the sensor also includes a second opening extending from the first side of the printed circuit board to the second side of the printed circuit board, the second opening having a second receiving electrode and a second transmitting electrode, the fluid flow being a first portion of the fluid flow and a second portion of the fluid flowing through the second opening and a second impedance signal is generated using the second transmitting electrode and the receiving electrode.

[0207] The sensor may be implemented such that the second receiving electrode is separated from the first receiving electrode such that the impedance signal and the second impedance signal are different.

[0208] The sensor may be implemented such that the printed circuit board is a standard printed circuit board.

[0209] The sensor may be implemented to be part of a sensor stack consisting of an impedance sensor and a second impedance sensor.

[0210] The sensor may be implemented to include a temperature sensor.

[0211] The sensor may be mounted such that the temperature sensor is electrically isolated from the fluid flow.

[0212] The sensor may be mounted such that the temperature sensor is insulated by a layer of varnish or epoxy adhesive.

[0213] The sensor may be mounted such that the temperature sensor is within the second opening.

[0214] The sensor may be mounted such that the temperature sensor is coplanar with the receiving and transmitting electrodes.

[0215] The sensor may be mounted such that the opening is closed at a first end and open at a second end.

[0216] The sensor may be mounted such that an external portion of the PCB is metallized.

[0217] The sensor may be mounted such that the corners of the PCB are metallized.

[0218] The sensor may be implemented such that the PCB is an additively manufactured PCB.

[0219] A sensing system is presented that includes a fluid channel through which a fluid flows and a sensor in the fluid channel. The sensor includes a printed circuit board (PCB) and an opening in the PCB that includes a receiving electrode spaced apart from a transmitting electrode. The fluid flows through the opening in direct contact with the transmitting and receiving electrodes. When a voltage is applied to the transmitting electrode, a current is received at the receiving electrode. The sensor also includes a communication component that communicates a calculated electrical parameter for the fluid, the electrical parameter being calculated based on the received current.

[0220] The system can be implemented such that the fluid channel includes a mixing chamber that receives the first component stream and the second component stream.

[0221] The system may be implemented such that the sensor is downstream of the mixing chamber.

[0222] The system may be implemented further including a second sensor in the fluid channel, the second sensor being upstream of the mixing chamber.

[0223] The system may be implemented such that the electrical parameter is impedance, conductivity, or permittivity.

[0224] The system may be implemented such that the electrical parameter is indicative of an air bubble in the fluid flow.

[0225] The system may be implemented such that an electrical parameter is indicative of the mixture ratio.

[0226] The system may be implemented such that the electrical parameter is indicative of the mixing quality across the fluid flow.

[0227] The system may be implemented such that the electrical parameter is indicative of fluid life.

[0228] The system may be implemented such that an electrical parameter is indicative of cure progress.

[0229] The system may be implemented such that the transmit electrodes are perpendicular to the surface of the PCB.

[0230] The system may be implemented such that the transmit electrodes are aligned with the length of the aperture and the receive electrodes are parallel to the transmit electrodes.

[0231] The system may be implemented to include a second opening having a second length, a second width perpendicular to the second length, and a second thickness perpendicular to the second length and width, where the second length is at least three times the second width and the second width is greater than the second thickness.

[0232] The system may be implemented to include a second transmit electrode within the second aperture and a second receive electrode parallel to the second transmit electrode within the aperture.

[0233] The system may be implemented such that the second opening is parallel to the first opening.

[0234] The system may be implemented such that the sensor is a first sensor and further includes a second sensor.

[0235] The system may be implemented such that the second sensor is separate from the first sensor.

[0236] The system may be implemented such that the second sensor is parallel to the first sensor.

[0237] The system may be implemented to further include a third sensor.

[0238] The system may be implemented to further include a control signal generator that generates a control signal based on the conductivity signal.

[0239] The system may be implemented such that the control signal is a purge signal.

[0240] The system may be implemented such that the control signal is the motor speed.

[0241] The system may be implemented such that the transmit electrode has an electrode length and the aperture has an aperture length, the aperture length being greater than the electrode length.

[0242] The system may be implemented such that the PCB is the first PCB. The sensor also includes a second printed circuit board (PCB) and a second opening in the second PCB, the second opening including a second receiving electrode spaced apart from the second transmitting electrode, and the fluid flows through the second opening in direct contact with the second transmitting electrode and the second receiving electrode.

[0243] The system may be implemented such that the second opening is positioned such that the fluid flows through the first opening before flowing through the second opening.

[0244] The system may be implemented such that the second PCB is coupled to the first PCB.

[0245] The system may be implemented such that the second PCB is a two-layer PCB and the first PCB is a four-layer PCB.

[0246] The system may be implemented such that the first PCB includes a temperature sensor.

[0247] The system may be implemented such that the temperature sensor is electrically isolated from the fluid flow.

[0248] The system may be implemented such that the temperature sensor is insulated by a layer of varnish or epoxy adhesive.

[0249] The system may be implemented such that the PCB includes a temperature sensor.

[0250] The system may be implemented such that the temperature sensor is isolated from the fluid flow.

[0251] The system may be implemented such that the temperature sensor is insulated by a layer of varnish or epoxy adhesive.

[0252] The system may be implemented such that the first opening receives a first fluid stream and the second opening receives a second fluid stream, the first fluid stream and the second fluid stream being chemically distinct.

[0253] A dispensing system is presented that includes a mixer that receives a first fluid stream and a second fluid stream and produces a mixture. The system also includes a sensor in the fluid flow stream of the dispensing system. The sensor includes a printed circuit board that includes an opening, a transmitting electrode on a first portion of the opening, and a receiving electrode on a second portion of the opening. The mixture flows through the opening and contacts the transmitting and receiving electrodes, and the sensor produces a sensor signal indicative of the mixture. The system also includes a dispenser that dispenses the mixture. The system also includes a communication component that communicates the sensor signal.

[0254] The system may be implemented such that the mixer is a static mixer.

[0255] The system may be implemented such that the mixer is an active mixer.

[0256] The system may be implemented such that the sensor is downstream of the mixer.

[0257] The system may be implemented such that the sensor is upstream of the mixer and downstream of the first fluid source.

[0258] The system may be implemented such that the printed circuit board is positioned within the fluid flow stream such that the fluid flows through the opening.

[0259] The system may be mounted so that the printed circuit board is perpendicular to the fluid flow.

[0260] The system can be implemented such that the sensor is a first sensor located downstream of the mixer and the dispensing system includes a second sensor located upstream of the mixer.

[0261] The system may be implemented such that the fluid stream includes a first component fluid stream and a second component fluid stream, and the sensor receives both the first component fluid stream and the second component fluid stream.

[0262] The system can be implemented such that a first fluid flows through the opening and a second fluid flows through a second opening in the printed circuit board, the second opening including a second transmitting electrode and a second receiving electrode.

[0263] The system can be implemented to include a housing that contains the sensor and physically separates the first fluid stream from the second fluid stream.

[0264] The system may be implemented such that a second sensor is disposed in the first fluid stream and further includes a third sensor disposed in the second fluid stream upstream of the mixer.

[0265] The system may be implemented such that the opening is a first opening and the printed circuit board includes a second opening having a second transmitting electrode and a second receiving electrode.

[0266] The system may be implemented such that the transmit electrodes are parallel to the length of the aperture and parallel to the receive electrodes.

[0267] The system may be implemented to include an analyzer that receives the sensor signal and provides an indication.

[0268] The system may be implemented such that the indication includes an aging of the first fluid.

[0269] The system may be implemented such that the analyzer determines the indication by comparing the sensor signal to stored sensor signals.

[0270] The system may be implemented such that the display includes a hardening progress display of the mixture.

[0271] The system may be implemented such that the display includes the mix ratio.

[0272] The system can be implemented to include an analyzer that receives a first sensor signal from a first sensor, a second sensor signal from a second sensor, and a third sensor signal from a third sensor.

[0273] The system may be implemented such that the analyzer provides a mix ratio indication based on the received sensor signal.

[0274] The system may be implemented such that the analyzer provides a batch quality indication based on the received sensor signals.

[0275] The system may be implemented such that the analyzer provides an aging indication based on the received sensor signal.

[0276] The system can be implemented such that the indication includes mixing quality across a cross-section of the fluid flow.

[0277] The system may be implemented such that the analyzer determines the indication by applying a predictive model to the sensor signal.

[0278] The system may be implemented such that the display includes a bubble display.

[0279] The system may be implemented such that the air bubble indication includes an indication that the sensed conductivity has spiked.

[0280] The system may be implemented such that the conductivity spike is greater than a relative threshold value.

[0281] The system may be implemented such that, based on the indication, a control signal is generated to purge the fluid flow.

[0282] The system may be implemented such that, in response to the sensor signal, a control signal is provided to the motor to adjust the motor speed of the motor.

[0283] The system may be implemented such that purging is automatically initiated in response to a sensor signal.

[0284] The system may also be implemented to include a display component that receives the sensed signal and provides a visual representation of the sensed signal.

[0285] The system may be implemented such that the visual indication is a mixed quality indication.

[0286] The system may be implemented such that a communications component provides the sensed signals to a data store.

[0287] The system may be implemented such that the sensor includes a temperature sensor.

[0288] The system may be implemented such that the sensor is coplanar with the receive and transmit electrodes.

[0289] The system may be implemented such that the temperature sensor is isolated from the fluid flow.

[0290] The system may be implemented such that the temperature sensor is insulated by a layer of varnish or epoxy adhesive.

[0291] The system may be implemented such that the sensor is a first sensor and further includes a second sensor coupled to the first sensor.

[0292] The system may be implemented such that the bond includes a conductive material.

[0293] The system may be implemented such that the conductive material is solder.

[0294] The system may be implemented such that a second sensor is coupled to and includes a second opening such that the fluid flows through the first opening before flowing through the second opening.

[0295] The system may be implemented such that the first sensor is a four-layer PCB and the second sensor is a two-layer PCB.

[0296] The system may be implemented such that the PCB is tilted non-orthogonally relative to the fluid flow.

[0297] A method of measuring mixing quality is presented that includes providing a first fluid and a second fluid to a mixer. The method also includes receiving the mixture from the mixer and passing a portion of the mixture through a sensor, the sensor including a printed circuit board having an opening for receiving the portion of the mixture such that the portion of the mixture directly contacts a transmitting electrode and a receiving electrode. The method also includes generating a sensor signal indicative of the mixing quality.

[0298] The method may be implemented such that the sensor fills a majority of the area through which the mixture flows and the mixture flows through the opening.

[0299] The method may be implemented such that the sensor includes a plurality of openings, the mixtures flowing through the plurality of openings, a portion of the first mixture flowing through the first opening and a portion of the second mixture flowing through the second opening.

[0300] The method may be implemented to also include receiving a first electrical parameter signal from a first electrode pair associated with the first opening. The method also includes receiving a second electrical parameter signal from a second electrode pair associated with the second opening. The sensor signal is based on the first electrical parameter signal and the second electrical parameter signal, where the first electrical parameter signal and the second electrical parameter signal are impedance signals, conductivity signals, or permittivity signals.

[0301] The method may be implemented such that the first pair of electrodes is spaced and separated from the second pair of electrodes.

[0302] The method may be implemented such that the first electrical parameter signal differs from the second electrical parameter signal, the method further including providing a blend quality indication based on a comparison of the first electrical parameter signal and the second electrical parameter signal.

[0303] The method may be implemented to include comparing intra-signal statistics and inter-signal statistics of the first conductivity signal and the second conductivity signal.

[0304] The method may be implemented such that the intra-signal statistics include the mean, variance, and covariance.

[0305] The method may also be implemented to include applying a predictive model to generate a prediction for the mixture based on the sensor signal.

[0306] The method may be implemented such that the prediction is a predicted barge time.

[0307] The method may be implemented to further include detecting air bubbles in the provided first fluid and removing the air bubbles from the first fluid.

[0308] The method may be implemented such that the air bubble is detected by a sensor.

[0309] The method may be implemented such that removing includes generating a purge signal that causes a valve to open so that air bubbles are bypassed.

[0310] The method may be implemented to include verifying that the air bubbles have been removed.

[0311] The method may be implemented such that verifying includes passing the first fluid through a second sensor downstream from the sensor.

[0312] The method may be implemented to include providing a third fluid to the mixer.

[0313] The method may be implemented such that a first electrode pair receives a first fluid and a second electrode pair receives a second component.

[0314] The method can be implemented such that the sensor includes a housing that maintains separation between the first and second fluids while flowing through the first and second electrode pairs.

[0315] A bubble detection system for a material dispensing system is presented that includes a sensor system in fluid contact with the flowing material and generating a signal. The sensor includes a printed circuit board having an opening extending through a thickness of the printed circuit board from a first side to a second side. The sensor also includes a transmitting electrode on a first portion of the opening that transmits a voltage. The sensor also includes a receiving electrode on a second portion of the opening that receives a conduction current. The sensor also includes an electrical parameter calculator that periodically generates an impedance, conductivity, or permittivity based on the received current. The sensor also includes a conductivity analyzer that receives the calculated electrical parameter, detects spikes, compares the spikes to a threshold, and generates an air bubble detection indication if the spike is outside the threshold.

[0316] The air bubble detection system may also be implemented to include a communication component that communicates the air bubble detection indication.

[0317] The air bubble detection system may be implemented such that the air bubble detection indication includes a purge command and the communication component communicates the purge command to the valve controller.

[0318] The air bubble detection system may be implemented such that the threshold is a relative threshold based on previously received signals.

[0319] The air bubble detection system may be implemented such that the opening is a first opening, the printed circuit board has a plurality of openings, each opening having a transmitting electrode and a receiving electrode, and the plurality of openings are coplanar.

[0320] The air bubble detection system may be implemented such that each of the multiple openings are parallel to one another.

[0321] The air bubble detection system may be implemented such that each of the multiple openings is parallel to the length of the printed circuit board, the length being the longest edge of the printed circuit board.

[0322] The air bubble detection system may be implemented such that each of the openings has a length and a width, the length being at least three times as long as the width.

[0323] The present bubble detection system may be implemented such that fluid flows between the transmitting and receiving electrodes.

[0324] The air bubble detection system may be implemented such that the opening includes a first end and a second end, with a receiving electrode and a transmitting electrode separated at each end.

[0325] The air bubble detection system may be implemented such that the PCB is a first PCB and further includes a second PCB stacked above or below the first PCB.

[0326] The air bubble detection system may be implemented such that a first PCB is mechanically coupled to a second PCB.

[0327] The air bubble detection system may be implemented such that the mechanical connection includes solder.

[0328] The air bubble detection system may be implemented such that the first PCB is a four-layer PCB and the second PCB is a two-layer PCB.

[0329] The air bubble detection system may be implemented with a temperature sensor.

[0330] A method of removing air bubbles from a material dispensing system is presented that includes detecting an indication of an air bubble in a fluid flow with a sensor. The sensor includes a printed circuit board having an opening extending from a first point on the printed circuit board to a second point on the printed circuit board, the opening extending through a thickness of the printed circuit board, a transmitting electrode on a first surface of the opening, and a receiving electrode on a second surface of the opening opposite the first surface of the opening, the printed circuit board configured to be disposed in the fluid line such that the fluid flow passes through the opening. The method also includes receiving a sensed electrical parameter value from the sensor, comparing the sensed electrical parameter value to a threshold value, generating a command to purge the fluid line if a conductivity spike is detected based on the comparison, and communicating the purge command to a valve controller.

[0331] The method may be implemented such that the threshold is a relative threshold based on previously received sensor signals.

[0332] The method may be implemented such that the printed circuit board includes a plurality of openings, the plurality of openings being spaced apart on the printed circuit board such that a first portion of the fluid travels through the first opening and a second portion of the fluid travels through the second opening.

[0333] The method may be implemented such that the sensor is a first sensor, and further includes detecting that the air bubble has been removed using a second sensor downstream of the first sensor.

[0334] A method of forming a sensor is presented that includes creating an opening in a printed circuit board, the opening having a length, a width and a thickness, the thickness extending through the printed circuit board, and adhering a first electrode and a second electrode within the opening.

[0335] The method may be implemented such that the bonding includes metallizing an inner surface of the opening and separating the first electrode from the second electrode.

[0336] The method may be implemented such that the separating includes removing a portion of the metallized surface.

[0337] The method may be implemented such that removing a portion of the metallized surface includes drilling the portion of the metallized surface.

[0338] The method may be implemented to include drilling a second portion of the metallized surface.

[0339] The method may be implemented such that the opening is a first opening, and further includes creating a second opening in the printed circuit board, the second opening having a length, a width, and a thickness, the second opening being spaced apart from the first opening.

[0340] The method includes creating a third opening in the printed circuit board, the third opening having a length, a width, and a thickness, the third opening being spaced apart from the opening, and the first opening, the second opening, and the third opening may be implemented as spaced apart on the printed circuit board.

[0341] The method may be implemented such that a first space between the first opening and the second opening is the same as a second space between the second opening and the third opening.

[0342] The method may be implemented such that a first space between the first opening and the second opening is different from a second space between the second opening and the third opening.

[0343] The method can be implemented such that the metallizing includes applying a layer of copper to the interior surfaces of the openings.

[0344] The method may be implemented to further include creating a second opening in a second printed circuit board, adhering the third electrode and the fourth electrode within the second opening, and bonding the second printed circuit board to the first circuit board.

[0345] The method may be implemented such that the second printed circuit board is a two-layer PCB and the first printed circuit board is a four-layer PCB.

[0346] a mixer having a first material inlet, a second material inlet, and a material outlet; and a first sensor disposed at the first material inlet; A material dispensing system is presented that includes a second sensor disposed at the second inlet and a third sensor disposed at the material outlet, where the first sensor, the second sensor, and the third sensor are in fluid contact with material flowing through the material dispensing system, a material analyzer that receives a first sensor signal from the first sensor, a second sensor signal from the second sensor, and a third sensor signal from the third sensor and provides an indication, and a communication component that communicates the indication to a second device.

[0347] The material dispensing system can be implemented such that the first sensor, the second sensor, and the third sensor all include a printed circuit board.

[0348] The material dispensing system can be implemented such that the first sensor includes an opening, the opening includes a transmitting electrode and a receiving electrode, and the transmitting electrode and the receiving electrode are in fluid contact with material flowing through the material dispensing system.

[0349] The material dispensing system can be implemented such that the first sensor includes a second opening coplanar with the opening, the second opening including a second transmitting electrode and a second receiving electrode.

[0350] The material dispensing system can be implemented such that the first sensor includes a temperature sensor.

[0351] The material dispensing system can be implemented such that the temperature sensor is coplanar with the transmitting and receiving electrodes.

[0352] The material dispensing system can be implemented such that the first sensor includes a printed circuit board and the opening is a part of the printed circuit board.

[0353] The material dispensing system can be implemented such that the printed circuit board is a first printed circuit board and the first sensor includes a second printed circuit board coupled to the first circuit board.

[0354] The material dispensing system may be implemented such that the material analyzer is a blend analyzer and the display is a blend display.

[0355] The material dispensing system can be implemented such that the mix indication is a real-time mix ratio.

[0356] The material dispensing system can be implemented such that the mixing indication is an indication of an incomplete mix.

[0357] The material dispensing system can be implemented such that the mix indication is a visual, tactile, or audible warning.

[0358] The material dispensing system can be implemented such that the material analyzer is a cure analyzer and the indication is a cure indication.

[0359] The material dispensing system can be implemented such that the hardening indication is an indication that the flow lines should be purged.

[0360] The material dispensing system can be implemented such that the curing indication is an indication that purging of cured material is complete.

[0361] The material dispensing system can be implemented such that the material analyzer is an air bubble detector and the indication is a detected air bubble.

[0362] The material dispensing system can be implemented such that the material analyzer is a compositional drift analyzer and the indication is a detected change in composition.

[0363] The material dispensing system can be implemented such that the material analyzer is a start-up analyzer and the indication is a mix ratio stabilization indication.

[0364] The material dispensing system can be implemented such that the material analyzer is a homogeneity analyzer and the indication is an indication of a heterogeneous fluid flow.

[0365] The material dispensing system can be implemented such that the indication includes a command, the communications component automatically provides the command to the second device, and the command is automatically implemented by the second device.

[0366] The material dispensing system can be implemented such that the command is a motor speed signal and the second device is a motor controller for a pump that provides the first material to the first material inlet.

[0367] The material dispensing system can be implemented such that the command is a valve control command and the second device is a valve controller.

[0368] The material dispensing system can be implemented such that the valve control command is a valve open command or a valve close command.

[0369] The material dispensing system can be implemented such that the display includes a graphical user interface update and the second device includes a display component that automatically updates the graphical user interface when the user interface update is received.

[0370] The material dispensing system can be implemented such that the graphical user interface updates include real-time calculated mix ratios and target mix ratios.

[0371] The material dispensing system can be implemented such that the graphical user interface includes a display.

[0372] The material dispensing system can include a PCB board, where the PCB board can be implemented to include a first sensor and a second sensor.

[0373] The material dispensing system can be implemented such that the first sensor and the second sensor are separate.

[0374] The material dispensing system can be implemented to include a separation component that separates a first fluid flowing past a first sensor from a second component flowing past a second sensor.

[0375] An electrical parameter sensor is presented that includes a first printed circuit board including a first opening, a first transmitting electrode in the first opening, and a first receiving electrode in the opening, with the fluid flowing through the first opening. The system also includes a second printed circuit board including a second opening, a second transmitting electrode in the second opening, and a second receiving electrode in the second opening, with the fluid flowing through the second opening. The first printed circuit board is positioned over the second printed circuit board such that the first transmitting electrode is aligned with the second transmitting electrode.

[0376] The electrical parameter sensor may be implemented such that the first transmitting electrode and the second transmitting electrode are electrically connected to each other and in direct contact with the material flow.

[0377] The electrical parameter sensor may be mounted such that the first receiving electrode and the second receiving electrode are electrically connected to one another and in direct contact with the material flow.

[0378] The electrical parameter sensor may be implemented such that the electrical parameter is conductivity, impedance, or permittivity.

[0379] The electrical parameter sensor may be implemented such that the opening is closed at both the first end and the second end.

[0380] The electrical parameter sensor may be implemented such that the first printed circuit board is a four-layer printed circuit board having an edge connector interface.

[0381] The electrical parameter sensor may be implemented such that the second printed circuit board is a second layer printed circuit board.

[0382] The electrical parameter sensor may be implemented to include a temperature sensor.

[0383] The electrical parameter sensor may be mounted such that the temperature sensor is electrically isolated from the material flow.

[0384] The electrical parameter sensor may be implemented such that the temperature sensor is coplanar with the first transmitting electrode and the first receiving electrode.

[0385] The electrical parameter sensor may be mounted such that the first printed circuit board and the second printed circuit board are mechanically coupled.

[0386] The electrical parameter sensor may be mounted such that the first printed circuit board and the second printed circuit board are soldered together.

[0387] The electrical parameter sensor may be implemented to further include a sealing ring that engages the material flow line.

[0388] The electrical parameter sensor may be implemented such that the sensor generates a first signal from a first transmitting electrode and a first receiving electrode, and the sensor generates a second signal from a third transmitting electrode and a third receiving electrode.

[0389] The electrical parameter sensor may be implemented such that the third transmitting electrode and the third receiving electrode are coplanar with the first transmitting electrode and the first receiving electrode.

[0390] The electrical parameter sensor may be mounted such that the opening is closed at a first end and open at a second end. EXAMPLES

[0391] These examples are merely illustrative and are not intended to unduly limit the scope of the appended claims. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the present disclosure are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. However, any numerical value inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. At the very least, each numerical parameter should be construed by at least applying ordinary rounding techniques in light of the number of reported significant digits, but this is not intended to limit the application of the doctrine of equivalents to the scope of the claims.

[0392] Unless otherwise stated, all chemicals used in the examples can be obtained from the suppliers stated. Adhesives used in exemplary embodiments can include those adhesives described below.

[0393] Example 1: PCB Sensor Design A sensor was designed as shown in Figure 21A. First, holes were milled for the electrodes and temperature sensor. After holes were drilled or slots were milled in the PCB, the PCB was chemically coated with copper. This coating was done in a tank filled with liquid chemicals. After this process, a thin layer of 1 μm copper lined the inside of the milled openings. To increase the thickness of this layer, additional copper was added by galvanic copper deposition. After this step, a 20 μm thick layer of copper lined the inside of the holes and slots. There were two conductive surfaces facing each other, but they were electrically connected together at both ends of the slot. Figure 21B shows the PCB sensor at this point in the process.

[0394] To obtain two electrically isolated electrodes, the connections at the ends of the slots were removed by drilling or milling holes or slots at the ends of the plated slots, thus removing the copper plating of the plated slots in the curved areas at the ends.

[0395] Example 2: PCB Sensor and Sensor Stack A sensor, sensor stack as shown in FIG. 22, was designed with the dimensions shown.

[0396] Example 3: Metering Pump System Sensor Application for Continuous Dispensing System The system (PK2D variable volumetric metering pump from Fluidic Systems, Santa Ana, Calif.) provided a continuous flow of material (3M™ Scotch-Weld™ Epoxy Adhesive 2216NS, a two-part epoxy adhesive from 3M, St. Paul, Minnesota) to the dispense valves. Mixing nozzles (Model MC-13-24 from Sulzer Mixpac, Haag, Switzerland) were attached to the dispense valves approximately 3 meters from each of the metering pumps. Sensors (as shown in FIG. 21A) were attached to the ends of the mixing nozzles using threaded adapters to provide a secure connection. Conductivity and temperature signals were received and graphed over time against the measured input variables.

[0397] A pressure sensor was placed external to each positive displacement pump, and the temperature, conductivity, and pressure signals could all be simultaneously captured and displayed.

[0398] Using the above system, a series of experiments were conducted to form a resin mixture with varying ratios and flow rates of Part A and Part B materials. Part A of the resin mixture was an accelerator and Part B of the resin mixture was a base. In real time, temperature and conductivity signals were collected, recorded, plotted against time, and shown in FIG. 23. FIG. 23 shows when the resin mixture flow rate was first set at 11% and then how changing the ratio of Part A to Part B of the resin mixture affected the conductivity and temperature. FIG. 23 also shows temperature and conductivity data plots for a second set of experiments conducted where the ratio of Part A:Part B was held at 3:2 and the flow rate was increased. Small spikes were observed in the conductivity readings across the different flow rate and ratio conditions.

[0399] Example 4: Metering pump system sensor application for continuous dispensing Using the same system described above in Example 3, another set of experiments was completed, this time including two sensors in series, where the resin mix ratio and flow rate were varied at a fixed temperature, and pressure measurements were added to the data collection. The purpose of the two sensors in series was to determine the variability between sensors. This was repeated with three other pairs of sensors. Temperature, conductivity, and pressure measurements versus time were collected, recorded, and plotted versus time, with one pair of sensors shown in FIG. 24. By recording the pressure measurements simultaneously in addition to the conductivity measurements and comparing these two sets of measurements, it was shown that the spike change in conductivity was due to a wink in the metering pump when it changed direction. In the experiments performed, the Part A material appeared to be the main driver of the spike. A delay of about 8 seconds was consistently observed between the pressure wink and the conductivity spike. The inclusion of pressure measurements in the data collection allows for an explanation of the spike phenomenon. This is as opposed to a surge or other change in the relative materials (i.e., a change in ratio, or other change in homogeneity such as air bubbles in the resin system).

Claims

1. An electrical property sensor, a printed circuit board having a first side separated from a second side by a thickness, the first side having a length and a width; an opening extending from the first side of the printed circuit board to the second side of the printed circuit board, the opening comprising a receive electrode and a transmit electrode; An electrical property sensor in which when fluid flows through the opening and a voltage is supplied at the transmitting electrode, a current is measured at the receiving electrode.

2. The sensor of claim 1 , wherein the current is convertible into an impedance value, a conductivity value, or a permittivity signal.

3. 3. The sensor of claim 1, wherein the opening is parallel to the length and perpendicular to the width.

4. The sensor of claim 1 , wherein the receiving electrode and the transmitting electrode each have an electrode width that is substantially the thickness.

5. The sensor of claim 1 , wherein the receiving electrode and the transmitting electrode each have an electrode length that is shorter than an aperture length.

6. The sensor of claim 1 , wherein the receiving electrode comprises a metal.

7. The sensor of claim 6 , wherein the transmitting electrode also comprises the metal.

8. The opening is a first opening, and the sensor also includes: a second opening extending from the first side of the printed circuit board to the second side of the printed circuit board, the second opening comprising a second receive electrode and a second transmit electrode; 2. The sensor of claim 1, wherein the fluid flow is a first portion of a fluid flow and when a second portion of the fluid flows through the second opening, a second impedance signal is generated using the second transmitting electrode and the second receiving electrode.

9. 10. The sensor of claim 9, wherein the second receiving electrode is separated from the first receiving electrode such that the impedance signal and the second impedance signal are different.

10. The sensor of claim 1 further comprising a temperature sensor.

11. The sensor of claim 10 , wherein the temperature sensor is electrically isolated from the fluid flow.

12. 1. A sensing system comprising: a fluid channel through which a fluid flows; a sensor in the fluid channel, a printed circuit board (PCB); an opening in the PCB comprising a receiving electrode spaced apart from a transmitting electrode; an opening through which the fluid flows in direct contact with the transmitting electrode and the receiving electrode, and a current is received at the receiving electrode when a voltage is applied to the transmitting electrode; a communication component that communicates a calculated electrical parameter for the fluid, the electrical parameter being calculated based on the received current, the electrical parameter being an impedance, a conductivity, or a permittivity; A sensing system comprising:

13. The system of claim 12 , wherein the fluid channel comprises a mixing chamber that receives a first component flow and a second component flow.

14. The system of claim 13 , wherein the sensor is downstream of the mixing chamber.

15. 1. A method of forming a sensor, comprising: creating an opening in a printed circuit board, the opening having a length, a width, and a thickness, the thickness extending through the printed circuit board; bonding a first electrode and a second electrode within the opening; A method comprising:

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