Systems and methods for direct heater diagnostics in high temperature molten liquid dispensing systems

Abstract

A system and method for direct heater diagnostics of a high temperature molten liquid dispensing system is disclosed. At least one of a current measurement (506) and a voltage measurement (508) is received from a respective current sensor (502) and / or voltage sensor (504) disposed in an electrical circuit that powers a heater associated with the dispensing system. The heater may be for an applicator or heated hose attached to the dispensing system, for a melter of the dispensing system, or for a pump of the dispensing system. A state (512) of the electrical circuit is determined based on the at least one of the current measurement and the voltage measurement.

Description

[Background technology]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to U.S. Provisional Patent Application No. 62 / 903,423, filed September 20, 2019, which is incorporated by reference in its entirety.

[0002] [Technical field] The present invention relates generally to fluid dispensing, and more particularly to direct diagnostics for heaters and related components of high temperature melt (hot melt) fluid dispensing systems.

[0003] [background] Hot melt liquid dispensing systems are used in a variety of applications. For example, such systems may apply hot melt adhesives during the manufacture of disposable hygiene products. As another example, hot melt liquid dispensing systems may apply hot melt adhesives to assemble and / or seal various types of packaging, such as paper-based packaging for food and beverages.

[0004] In an exemplary configuration of a hot melt liquid dispensing system, a hot melt adhesive in solid form is fed into a melter containing a heated reservoir and / or a heated grid to produce a molten hot melt adhesive. After heating, the molten adhesive may be pumped through a heated hose to an applicator. The applicator includes a valve and a nozzle and is sometimes referred to as a dispensing "gun" or gun module. The applicator then dispenses the molten adhesive, often as a series of dots or lines, onto a desired surface or substrate. In many applications, precise location, timing, and quantity of adhesive application are always paramount. For example, dispensing an insufficient amount of adhesive can result in an ineffective bond, while excessive amounts of adhesive not only waste material but can also result in undesirable flow as the adhesive is applied to a surface.

[0005] Proper operation of the various heater components of a hot molten liquid dispensing system is a critical factor in achieving desired results, particularly in the dispensed adhesive. For example, a faulty heater component may not heat and / or maintain the molten adhesive at a specific temperature, resulting in a molten adhesive that is too viscous. This can adversely affect the amount and placement of the dispensed adhesive. Conversely, a molten adhesive that is too hot may have insufficient viscosity. This can result, for example, in an excessive amount of fluid being applied to a surface with each dispensing cycle. Low viscosity can also cause the dispensed adhesive to exhibit undesirable flow when applied to a surface. Additionally, excessive heat applied to the molten adhesive, such as in a melter, can cause scorching. Scorched adhesive can result in clogged filters and applicators, which can further discolor the dispensed adhesive and break the seal.

[0006] Still, diagnosing the various faults that can occur in heater components and associated circuitry presents many challenges. For example, a fault may not become apparent until some time after it occurs. For example, it may take several minutes for actual adhesive dispensing to be adversely affected by a heater failure. It may not be immediately apparent which of the various heater components involved (e.g., applicator heater, hose heater, or melter heater) has failed. In these cases, a problem with a heater component or associated circuitry must be inferred indirectly, for example, based on temperature behavior. Effective heater diagnosis may also require significant training and expertise on the part of the operator.

[0007] These and other shortcomings are addressed in the present invention. Summary of the Invention

[0008] Disclosed herein are systems and methods for direct diagnostics on heaters and related components of high temperature molten liquid dispensing systems.

[0009] An example of a hot molten liquid dispensing system may include a melter configured to melt a solid or semi-solid material into a hot molten liquid. The hot molten liquid dispensing system may include an electrical circuit configured to provide power to a heater associated with the hot molten liquid dispensing system. The electrical circuit may have at least one of a current sensor and a voltage sensor. The hot molten liquid dispensing system may include a controller. The controller may be configured to receive at least one of a current measurement and a voltage measurement from the at least one of the current sensor and the voltage sensor. The controller may be further configured to determine a state of the electrical circuit based on the at least one of the current measurement and the voltage measurement.

[0010] In one exemplary method, at least one of a current measurement and a voltage measurement may be received, the at least one of the current measurement and the voltage measurement may be associated with an electrical circuit configured to power a heater associated with a high-temperature molten liquid dispensing system, and a state of the electrical circuit may be determined based on the at least one of the current measurement and the voltage measurement.

[0011] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments and, together with the following detailed description, serve to explain the principles of the method and system of the present invention. [Brief explanation of the drawings]

[0012] [Figure 1A] FIG. 1A is a perspective view of an adhesive dispensing device according to one embodiment of the present invention.

[0013] [Figure 1B] FIG. 1B is another perspective view of the adhesive dispensing device shown in FIG. 1A.

[0014] [Figure 1C] FIG. 1C is yet another perspective view of the adhesive dispensing device shown in FIG. 1A.

[0015] [Figure 2] FIG. 2 is a cross-sectional view of the adhesive dispensing device shown in FIG. 1A taken along line 2-2 of FIG. 1A.

[0016] [Figure 3] 3 is a cross-sectional view of the adhesive dispensing device shown in FIG. 1A taken along line 3-3 in FIG. 1A.

[0017] [Figure 4] FIG. 4 shows a schematic diagram of an electronic circuit board configuration according to one embodiment of the present invention.

[0018] [Figure 5] FIG. 5 shows a data flow diagram according to one embodiment of the present invention.

[0019] [Figure 6] FIG. 6 shows a method flowchart according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] Aspects of the present invention will now be described in detail with reference to the drawings, in which like reference numerals refer to the same elements throughout unless otherwise specified.

[0021] The disclosed systems and methods relate to diagnostic techniques for heaters and associated components or elements of high-temperature molten liquid dispensing systems. While variously referred to as "heater diagnostics," the techniques described herein are not limited to diagnostics directed at the heater or heater system as a whole, but may also be used to diagnose various faults, conditions, etc., of any component, subcomponent, or element associated with the heater or heater system. This includes heat-generating elements, circuits, wires, conductors, traces (e.g., PCB copper traces), fuses, power control switches, or any component, subcomponent, or element that interacts with or affects heater operation. For example, the diagnostic techniques described herein may detect an open heat-generating element or a blown fuse. As another example, the diagnostic techniques may detect a broken or disconnected wire leading from a temperature control board to a heat-generating element.

[0022] 1A-3, an adhesive dispensing apparatus 10 according to one embodiment of the present invention is illustrated. The adhesive dispensing apparatus 10 includes a melt module 12 and a control module 14 electrically and / or physically coupled to the melt module 12. The melt module 12 is configured to include components related to receiving and melting a solid adhesive, while the control module 14 is configured to include electronic components for controlling the operation of the melt module 12. Each of the melt module 12 and the control module 14 is described in further detail below. Each of the melt module 12 and the control module 14 may be mounted to and supported by a base 18. The base 18 may include a metal body and be configured to releasably couple to each of the melt module 12 and the control module 14, such as via fasteners, which may include bolts, screws, etc. Although the melt module 12 and the control module 14 may alternatively be coupled to the base 18 in other embodiments.

[0023] When the melting module 12 and the control module 14 are coupled to the base 18, a thermal gap 32 may be defined between the melting module 12 and the control module 14. The thermal gap 32 may be configured to minimize and / or substantially eliminate heat transfer from the melting module 12 to the control module 14 to prevent damage to electronic components included in the control module 14 caused by heat generated by the melting module 12. The thermal gap 32 may include the space between the melting module 12 and the control module 14. Furthermore, while no particular type of material or construction is required, it is contemplated that the thermal gap 32 may include materials configured to prevent heat transfer, such as various types of insulation.

[0024] 1C, adhesive dispensing apparatus 10 may define a particular footprint F. The lower end of base 18 may define footprint F, which may be defined as the cross-sectional shape and area defined by the lower end of base 18. Footprint F may also, additionally or alternatively, be defined by the collective lower ends of melt module 12 and control module 14.

[0025] Adhesive dispensing apparatus 10 may include a melt module cover 26 and a control module cover 30 configured to provide selective access to melt module 12 and control module 14, respectively. Melt module cover 26 is configured to house components of melt module 12 and at least partially insulate melt module 12 from the ambient environment, while control module cover 30 is configured to house components of control module 14 and insulate control module 14 from melt module 12 and the ambient environment. The aforementioned thermal gap 32 may be specifically defined between melt module cover 26 and control module cover 30.

[0026] The control module 14 may include a controller 36. The controller 36 may include any suitable computing device configured to host software applications for monitoring and controlling various operations of the adhesive dispensing apparatus 10, as described herein. It will be understood that the controller 36 may include any suitable integrated circuit. In particular, the controller 36 may include memory and may be in signal communication with the human-machine interface (HMI) device 34. The memory may be volatile (such as some types of RAM), non-volatile (such as ROM, flash memory, etc.), or a combination thereof. The controller 36 may include additional storage (e.g., removable and / or non-removable storage), including, but not limited to, tape, flash memory, smart cards, CD-ROMs, digital versatile disks (DVDs) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, universal serial bus (USB) compatible memory, or any other medium that can be used to store information and that can be accessed by the controller 36. The memory of the controller 36 may be configured to store and recall on demand various metering operations to be performed by the adhesive dispensing device 10. The control module 14 may further include electrical connections 44 extending through the control module cover 30, which may be configured to establish a connection with an applicator and / or heated hose, transmit electrical power to the applicator and / or heated hose, and exchange communication signals.

[0027] As mentioned above, the control module 14 may include an HMI device 34 in signal communication with the controller 36. In the illustrated embodiment, the HMI device 34 may include a display, such as an OLED screen. However, the HMI device 34 may also include various types of inputs, additionally or alternatively providing the ability to control the controller 36 via, for example, buttons, soft keys, a mouse, voice-activated controls, a touch screen, movement of the controller 36, visual cues (e.g., moving a hand in front of a camera on the controller 36), etc. The HMI device 34 may provide output, including visual information, such as a visual representation of current conditions within the adhesive dispensing apparatus 10, via a graphical user interface, as well as acceptable ranges for these parameters via a display. Other outputs may include audio information (e.g., via a speaker), mechanical information (e.g., via a vibration mechanism), or a combination thereof. In various configurations, the HMI device 34 may include a display, a touch screen, a keyboard, a mouse, a motion detector, a speaker, a microphone, a camera, or any combination thereof. The HMI device 34 may further include any suitable device for inputting biometric information, such as fingerprint information, retinal information, voice information, and / or facial feature information, to require specific biometric information to access the controller 36. In addition to the HMI device 34, the control module 14 may include a pressure dial 40 to easily display pressure readings, such as air pressure readings.

[0028] Additionally, the controller 36 may be in signal communication with a remote device 38 (shown schematically in FIG. 1A ) that is remote from the control module 14. In one embodiment, the remote device 38 may include a display that is remote from the control module 14, such as an OLED display, although various types of conventional displays are contemplated. Alternatively, the remote device 38 may include an external computing device, examples of which may include a processor, a desktop computing device, a server computing device, or a portable computing device such as a laptop, tablet, or smartphone. Thus, the remote device 38 may provide an operator with the ability to interact with and control the controller 36 at a location remote from the adhesive-dispensing apparatus 10. The remote device 38 may be used as part of a cloud control system for the adhesive-dispensing apparatus 10.

[0029] The melt module 12 will now be described in more detail. The melt module 12 includes a melter subassembly 75 configured to receive solid or semi-solid pellets of adhesive material, either from manual loading by opening the lid assembly 50 or via an automated loading mechanism. The melter subassembly 75 can heat the pellets to a specific temperature to form a molten adhesive. The melt module 12 can also include a pump 150 configured to pressurize and dispense the molten adhesive to one or more downstream applicators 144 (shown schematically in FIG. 1B). The applicators 144 are also known as dispenser guns. As used herein, the term applicator 144 can refer to an applicator module comprised of a bank of applicators.

[0030] The melt module 12 may include a manifold 140 configured to receive pressurized molten adhesive from a pump 150 and distribute the adhesive to one or more outputs 54 on an exterior portion of the manifold 140. Portions of the manifold 140 and the pump 150 may be integrated into a single structural component (e.g., a manifold block). For example, a fluid chamber 158 portion of the pump 150 may extend into such a common structural component and supply pressurized molten adhesive to the manifold 140 portion. The manifold 140 may be configured with one or more heaters 148 (e.g., heating elements) to maintain adhesive flowing through the manifold 140 at a particular temperature. The heaters 148 may also serve to remelt adhesive material that has cooled within the manifold 140.

[0031] The manifold 140 may include an external manifold cover 142 with an opening for the output 54. The manifold cover 142 may be integral with the manifold 140 or may be separate and attachable and removable. Heated hoses 146 may be attached to the output 54 to receive pressurized molten adhesive from the manifold 140 and convey the adhesive to the applicator 144 for dispensing. The applicator 144 and heated hoses 146 may each be configured with one or more heaters to maintain the adhesive at a particular temperature. The heaters of the applicator 144 and heated hoses 146 may also serve to remelt adhesive material that has cooled within the component. The heaters of the applicator 144 and heated hoses 146, as well as the heater 148 of the manifold 140, may be in signal communication with the controller 36 to send status information (e.g., temperature measurements) to the controller 36 and to receive control signals from the controller 36. When not connected to the applicator 144, each of the multiple outputs 54 may be sealed with a plug.

[0032] The melt module 12 may include a melter subassembly 75 configured to receive solid material and define a receiving space 94 configured to accommodate molten adhesive. An upper wall of the melter subassembly 75 may define an opening 86 communicating with the receiving space 94, such that material may be manually deposited into the receiving space 94 through the opening 86 when the lid assembly 50 is rotated to the open position. However, when the lid assembly 50 is in the closed position, the lid assembly 50 may block the introduction of adhesive through the opening 86 into the receiving space 94. The receiving space 94 may define a specific volume designed for a particular adhesive operation. For example, the receiving space 94 may be configured to receive 4 kg of adhesive, although other sizes are contemplated.

[0033] The melter subassembly 75 may further include a level sensor 98 disposed within the receiving space 94. In particular, the level sensor 98 may be mounted to the interior surface of one of the side walls of the melter subassembly 75 and may be in signal communication with the controller 36 of the control module 14. The level sensor 98 may include a capacitive level sensor, although other types of level sensors are also contemplated. During operation, the level sensor 98 may monitor the level of material within the receiving space 94 and may send a signal to the controller 36 indicative of the adhesive level.

[0034] The melter subassembly 75 may further include a heater 114 configured to melt the adhesive. While depicted as being attached to and extending at least partially through the base of the melter subassembly 75, the heater 114 may alternatively or additionally be attached to any portion of the melter subassembly 75. It will be understood that the heater 114 may include any type of known heating device configured to melt the adhesive within the melter assembly. The melter subassembly 75 may further include a plurality of fins 118 extending upward from the base into the receiving space 94, which may be configured to be heated by the heater 114 to provide an increased surface area for heating and melting the adhesive. While a particular number, arrangement, and configuration of the fins 118 is illustrated, it is contemplated that the fins 118 may be alternatively configured as desired. Additionally, an outlet 122 may be defined within the base and may be in fluid communication with the receiving space 94 and configured to allow molten adhesive to flow through the outlet 122 and exit the receiving space 94. A cage 130 may be positioned adjacent the outlet 122. The cage 130 may be configured to act as a filter to prevent unmelted adhesive particles of a certain size from reaching the outlet 122 and solidifying around it, thereby blocking it.

[0035] A passageway 126 may extend from the outlet 122 to a pump 150 to supply the pump 150 with molten adhesive from the melter subassembly 75. The pump 150 may be a double-acting piston pump, although other types of pumps are contemplated. The pump 150 may operate to discharge molten adhesive from one or more of the outputs 54 via the manifold 140. The pump 150 may be controlled by the controller 36 of the control module 14 to provide a desired flow rate of molten adhesive through the outputs 54.

[0036] FIG. 4 shows a schematic diagram 400 of various circuit boards (e.g., printed circuit boards (PCBs) or printed circuit assemblies (PCAs)) and other electronic components of the adhesive dispensing apparatus 10 shown in FIGS. 1A-1C, 2, and 3. The circuit boards and other electronic components may be mounted within the control module 14, and particularly within the control module cover 30. One or more of the circuit boards and other electronic components shown in FIG. 4 may implement the controller 36 shown in FIGS. 2 and 3. In relation to power distribution, the control module 14 includes an on / off switch 405, a power distribution board 401, a chassis ground 403, a DC power supply 408, and a power distribution expansion board 416. In relation to system control, the control module 14 includes a control board 402. For temperature control (and AC power supply) of the various internal heaters of melt module 12 and the heaters of attached heated hoses (e.g., heated hose 146 of FIG. 1B ) and applicators (e.g., applicator 144 of FIG. 1B ), control module 14 includes a first temperature control board 413, a second temperature control board 414, and a third temperature control board 415. For user interaction, control module 14 includes a user interface (UI) board 406, a membrane switch panel 407, and a USB (universal serial bus) interface 404. In connection with pump operation and control, control module 14 further includes a pump solenoid valve 409, an air pressure sensor board 410, a pump pressure control valve 411, and a pump directional solenoid valve 412.

[0037] The various types of circuit boards described herein may, in some cases, include one or more sub-boards. Additionally or alternatively, a circuit board may collectively refer to several integrated circuit boards. A circuit board (including the sub-boards or integrated boards that make it up) may be variously referred to herein as a module. For example, the first temperature control board 413 may be referred to as a temperature control module.

[0038] To power the adhesive dispensing apparatus 10 and the connected heated hoses and applicators, the power distribution board 401 receives input AC power via AC connection point 441. A heated hose and applicator pair is sometimes referred to herein as an "H / A." The AC power is provided to the DC power supply 408 via connection point 445 on the power distribution board 401 and connection point 446 on the DC power supply 408. The DC power supply 408 then provides DC power (e.g., 24V) to the control board 402 via connection point 447 on the DC power supply 408 and connection point 448 on the control board 402.

[0039] For AC power to the internal heaters of melting module 12, AC power is sent to the first temperature control board 413 via connection point 443 on power distribution board 401 and connection point 422 on the first temperature control board 413. For AC power to the first H / A and second H / A heaters, AC power is sent to the first temperature control board 413 via connection point 443 on power distribution board 401 and connection point 426a on the first temperature control board 413. If the system includes more than two applicators (up to six in the illustrated embodiment), AC power is sent to the power distribution extension board 416 via connection point 451 on power distribution board 401 and connection point 452 on power distribution extension board 416. For AC power to the third H / A and fourth H / A heaters, AC power is sent to the second temperature control board 414 via connection point 455 on power distribution extension board 416 and connection point 426b on the second temperature control board 414. For AC power to the heaters 5H / A and 6H / A, the AC power is sent to the third temperature control board 415 via connection point 456 on the power distribution extension board 416 and connection point 426c on the third temperature control board 415.

[0040] The power distribution board 401 is configured with a plurality of fuses 444 associated with each power connection on the power distribution board 401. Each fuse in the plurality of fuses 444 may blow if the current on the associated power connection exceeds a threshold current. The power distribution board 401 and many of the other boards have several indicators, such as LED indicators. The indicators may reflect various conditions and status associated with various electrical circuits in the adhesive dispensing device 10, as well as control signals communicated between the board and other components of the adhesive dispensing device 10. As one example, an indicator 442 on the power distribution board 401 may illuminate when AC power is available to the power distribution board 401. Other indicators may illuminate or change color to indicate the availability of a control signal, the status of the board, the availability of power, or the status of a component (e.g., pump status or heater status), to name a few.

[0041] The control board 402 generally performs control functions for many aspects of the adhesive dispensing apparatus 10 and associated components (e.g., H / A). For example, the control board 402 may generate pump pressure control signals, control signals to activate or deactivate the fill system, and power relay control signals to the power distribution board 401. The control board 402 may provide a communications interface (wired and / or wireless) with an external control system, such as a cloud control system. The control board 402 may have a CPU for executing software or other such computer instructions, such as heater diagnostics. The control board 402 may be connected to a USB interface 404, for example, to receive preset setting recipes and to output, for example, an event log.

[0042] The UI board 406 and membrane switch panel 407 may implement the HMI device 34 shown in Figures 1A and 1C. The membrane switch panel 407 may accept direct manual input from a user. The UI board 406 may process the user input and communicate such input to the control board 402. The control board 402 may then validate the user input. For example, a user may use the membrane switch panel 407 to input a temperature setpoint for the heater 114 of the melter subassembly 75, and via the UI board 406, the control board 402 may cause the heater 114 to maintain that temperature setpoint.

[0043] The first temperature control board 413 is configured to provide AC power to control the internal heaters of the melting module 12. Such internal heaters may include a heater (e.g., heater 114) in the melter subassembly 75 that initially melts the adhesive material provided in the receiving space 94. Such internal heaters may also include a heater (e.g., heater 148) in the manifold 140 that maintains the molten adhesive at a particular temperature as it is pumped and dispensed from the manifold 140 to an output channel (e.g., output 54) toward an attached heater / air conditioner. The first temperature control board 413 provides AC power to the internal heaters via connection point 424. A temperature input signal from a temperature sensor (e.g., a resistance temperature detector (RTD)) located in the internal heater is received by the first temperature control board 413 via connection point 450. Based on the internal heater temperature input signals, the first temperature control board 413 supplies AC power to the internal heaters to maintain the heaters at their respective temperature setpoints (e.g., within their respective threshold ranges) using one or more controllers (e.g., PID controllers) implemented on the first temperature control board 413. One or more controllers on the first temperature control board 413 may be implemented for each heater. Additionally or alternatively, one controller on the first temperature control board 413 may be for the heaters in the melter subassembly 75 and another controller may be for the heaters in the manifold 140. The AC power may be supplied intermittently (e.g., switched). The duty cycle of each of the internal heaters may be based on the AC power supplied.

[0044] The first temperature control board 413 is further configured to provide AC power to and control the heaters of each of the first and second H / As. The heated hoses of the first and second H / As (and other H / As described herein) are connected to respective outputs 54 of the manifold 140 to receive molten adhesive. The first temperature control board 413 provides AC power to the heaters of the first and second H / As via connection points 428a and 429a, respectively, on the first temperature control board 413. Connection points 428a and 429a also serve to receive temperature input signals from temperature sensors located on the heaters of the first and second H / As, respectively. Thus, connection points 428a and 429a comprise input / output connections. Similar to the control of the internal heaters, the first temperature control board 413 implements one or more controllers (e.g., PID controllers) for the first and second H / A heaters, which cause AC power to be supplied to the first and second H / A heaters, respectively, based on an input temperature control signal. The AC power to the first and second H / A heaters may be supplied intermittently (e.g., switched), and the duty cycle of each of the first and second H / A heaters may be based on the AC power supplied to that heater. The first and second H / A heaters may be controlled and powered independently of each other. For example, a separate controller may be implemented for each H / A or for its single heater. A controller may also be implemented for each applicator or for each heated hose. A single controller may also be implemented to control both the internal heaters and the first and second H / A heaters.

[0045] With respect to H / A heater control for additional H / As, the second and third temperature control boards 414, 415 may perform functions similar to those of the first temperature control board 413. That is, the second and third temperature control boards 414, 415 may use separately implemented controllers to control AC power to the heaters of their associated H / As based on temperature input signals received from those heaters. In particular, the second temperature control board 414 is configured with an input / output connection point 428b that receives a temperature input signal from a temperature sensor in the heater of the third H / A and outputs an AC power supply to the heater of the third H / A. The second temperature control board 414 is also configured with an input / output connection point 429b that receives a temperature input signal from a temperature sensor in the heater of the fourth H / A and outputs an AC power supply to the heater of the fourth H / A. The second temperature control board 414 includes one or more controllers that control (e.g., intermittently) the AC power supplied to the third and fourth H / A heaters based on the respective temperature input signals from the heaters. The duty cycle of the third H / A or fourth H / A heaters can be set according to the AC power intermittently received from the second temperature control board 414. The power control can cause the heaters to reach or maintain a specified temperature setpoint (e.g., a threshold range).

[0046] The third temperature control board 415 is similarly configured with input / output connections 428c, 429c that receive temperature input signals from and supply AC power to the fifth and sixth H / A heaters, respectively. The third temperature control board 415 implements one or more controllers and controls the supply of AC power to the fifth and sixth H / A heaters. Heater control is based on the received temperature input signals. AC power may be supplied intermittently to the heaters and may govern the heater's duty cycle to reach or maintain a specified temperature setpoint (e.g., a threshold range). Other embodiments may include additional temperature control boards to accommodate additional H / As. Still other embodiments may include only the first temperature control board 413 or only the first and second temperature control boards 413, 414 if fewer H / As are required.

[0047] The first, second, and third temperature control boards 413, 414, and 415 may each include one or more sub-boards or PCAs. For example, the first, second, and third temperature control boards 413, 414, and 415 may each include a base board and a sub-board or PCA attached to or integrated therewith. The base board may include connection points for receiving AC power from the power distribution board 401 and connection points for providing AC power and control signals to the corresponding heaters. The sub-boards or PCAs may implement temperature controls (e.g., PID controllers) for the corresponding heaters and may send and receive communication signals from various other boards or components, such as other temperature control boards and the control board 402. The second temperature control board 414 includes a sub-board or PCA 414a, and the third temperature control board 415 includes a sub-board or PCA 415a.

[0048] Each of the first, second, and third temperature control boards 413, 414, and 415 is configured with one or more sets of current sensors and / or one or more sets of AC voltage sensors. Each of the first, second, and third temperature control boards 413, 414, and 415 includes a set(s) of current sensors 438a, b, and c and a set(s) of voltage sensors 440a, b, and c. The current and / or voltage sensor sets can be used for direct diagnostics of heaters and associated components (e.g., heating elements, heater circuits, conductors, wires, PCB traces, connectors, fuses, power control switches, etc.). Current and / or voltage measurements can be obtained in real time or near real time for direct heater diagnostics. The current sensors can include current sensor transformers (e.g., toroidal transformers) or in-line current sensors, such as Hall-effect sensors. The voltage sensors can include opto-isolator-based circuits configured to obtain one or more voltage measurements. The voltage measurements may include an indicator of whether AC voltage is present or absent, the magnitude of the AC voltage, and / or the AC line frequency. Although a set of sensors is represented in Figure 4 as a single element, a set of current sensors and / or a set of voltage sensors may include one or more sensors of each type.

[0049] It will be further understood that the diagnostic techniques described herein may be performed based on current measurements (excluding voltage measurements), based on voltage measurements (excluding current measurements), or based on both current and voltage measurements. Thus, while the first, second, and third temperature control boards 413, 414, 415 shown in FIG. 4 are each configured with both a current sensor and a voltage sensor in this specific example, the invention is not so limited, and a control board may be configured with only current sensor(s), only voltage sensor(s), or both current sensor(s) and voltage sensor(s).

[0050] As previously described, the first temperature control board 413 includes a set of current sensors 438a and a set of voltage sensors 440a. The set of current sensors 438a measures current in an AC power circuit that supplies AC power to the internal heater and the first and second H / A heaters connected to the first temperature control board 413. The set of voltage sensors 440a obtains voltage measurements (e.g., voltage presence / absence, voltage magnitude, and / or AC line frequency) of the AC power circuit. In some embodiments, additional sets of current and voltage sensors may be provided to obtain current and voltage measurements of the AC power circuit that supplies AC power to the internal heater, separate from the first and second H / A current and voltage measurements.

[0051] Set of current sensors 438a and set of voltage sensors 440a may each include one sensor for obtaining current and voltage measurements, respectively, on the AC power circuit of first temperature control board 413. Alternatively, set of current sensors 438a and set of voltage sensors 440a may each include two sensors, i.e., a first current sensor and a first voltage sensor for obtaining current and voltage measurements, respectively, on the AC power circuit powering the internal heater (e.g., at connection point 422), and a second current sensor and a second voltage sensor for obtaining current and voltage measurements, respectively, on the AC power circuit powering the first and second H / A heaters (e.g., at connection point 426a). Additionally, current sensor set 438a and voltage sensor set 440a may separately obtain current and voltage measurements of the AC power circuit powering the first H / A (e.g., at node 428a) and the AC power circuit powering the second H / A (e.g., at node 429a). That is, current sensor set 438a and voltage sensor set 440a may obtain current and voltage measurements for each channel. Additionally, current and voltage measurements may be obtained for each heater. The current and voltage measurements may be communicated to control board 402, for example, for use in direct heater diagnostics.

[0052] Similarly, the second temperature control board 414 is configured with a set of current sensors 438b and a set of voltage sensors 440b, and the third temperature control board 415 is configured with a set of current sensors 438c and a set of voltage sensors 440c. The set of current sensors 438b and the set of voltage sensors 440b obtain current and voltage measurements, respectively, on the AC power circuits supplying power to the third H / A and fourth H / A heaters connected to the second temperature control board 414. Similarly, the set of current sensors 438c and the set of voltage sensors 440c obtain current and voltage measurements, respectively, on the AC power circuits supplying power to the fifth H / A and sixth H / A heaters connected to the third temperature control board 415. The set of current sensors 438b, c and the set of voltage sensors 440b, c may each include a single sensor of the respective type, and current and voltage measurements may be taken for the AC power circuits of the respective second and third temperature control boards 414, 415 (e.g., at connection points 426b, c). Alternatively, the set of current sensors 438b and the set of voltage sensors 440b on the second temperature control board 414 may each have two sensors, i.e., a first current sensor and a first voltage sensor may obtain current and voltage measurements, respectively, of the AC power circuit supplying power to the third H / A heater (e.g., at connection point 428c), and a second current sensor and a second voltage sensor may obtain current and voltage measurements, respectively, of the AC power circuit supplying power to the fourth H / A heater (e.g., at connection point 429c), and the set of current sensors 438c and the set of voltage sensors 44cb on the third temperature control board 415 may be similarly configured for the AC power circuits supplying power to the fifth H / A and sixth H / A heaters connected to the third temperature control board 415.

[0053] It will be appreciated that the first, second, and third temperature control boards 413, 414, 415 implement independent, distributed temperature control and AC heater power supplies for the adhesive dispensing apparatus 10. This configuration provides a number of advantages. For example, the temperature control boards provide electrical isolation between the internal heaters, H / A heaters, and other circuit boards or components of the adhesive dispensing apparatus 10; in particular, they operate at relatively low voltages compared to the high-voltage AC power provided to the various heaters (e.g., low-voltage control board 402). As a result, AC disturbances in the circuitry powering the heaters, the temperature signal lines from the temperature sensors, or the temperature control boards themselves cannot propagate beyond the affected temperature control boards, preventing damage to other boards or components.

[0054] Additionally, this temperature control board configuration provides modularity. For example, if one temperature control board becomes defective, it can be switched in with a new temperature control board with relatively little effort. The independent temperature and power control features of the other temperature control boards are not affected. Furthermore, adhesive dispensing apparatus 10 can be customized to accommodate various numbers of H / As according to current or future needs. As previously mentioned, another temperature control board can be added to the configuration shown in FIG. 4 to control additional H / As. Conversely, if the current application requires a fewer number of H / As, the temperature control board can be removed.

[0055] 5 shows an example data flow diagram 500 associated with direct heater diagnostics that may be used, for example, with adhesive dispensing apparatus 10 of FIGS. 1A-1C, 2, and 3. In particular, heater diagnostics may be performed to determine the status of an electrical circuit that provides power (e.g., AC power) to a heater of adhesive dispensing apparatus 10, or a heater associated therewith. While described primarily in the context of hot melt adhesives, data flow diagram 500 (and its overall disclosure) may be applicable to any hot melt liquid or hot melt liquid dispensing system.

[0056] 4 . Additionally or alternatively, one or more voltage measurements 508 are received from a voltage sensor 504, such as any of voltage sensors 440a, b, c. As previously mentioned, the diagnostic techniques described herein may be performed using only the current sensor(s) 502, only the voltage sensor(s) 504, or both the current sensor 502 and the voltage sensor 504 (as well as the current measurements 506 and voltage measurements 508). The current sensor 502 and the voltage sensor 504 may be associated with a heater or related component of the adhesive dispensing apparatus 10. For example, the heater may include the heater 114 of the melter subassembly 75, the heater 148 of the manifold 140, a heater of an applicator 144 connected to the adhesive-dispensing device 10, or a heater of a heated hose 146 connecting the applicator 144 to the adhesive-dispensing device 10. The current measurement 506 may include the current (e.g., amperes) in an electrical heater circuit powering the heater associated with the current sensor 502. The voltage measurement 508 may include an indicator of voltage presence / absence, voltage magnitude, AC line frequency, or any combination thereof. The current measurement 506 and the voltage measurement 508 may include multiple measurements, such as measurements taken at regular intervals over a period of time. This may allow for predictive analysis, such as preemptively replacing or repairing parts before failure occurs.

[0057] The current sensor 502 and voltage sensor 504 may be located on the first, second, and / or third temperature control boards 413, 414, 415. Using the first temperature control board 413 as an example, the first temperature control board 413 may define, at least in part, an electrical heater circuit that provides power to one of the internal heaters or one of the first H / A or second H / A heaters connected to the first temperature control board 413. In the case of an internal heater, the electrical heater circuit may include a connection point 422 for receiving AC power from the power distribution board 401, a connection point 424 for transmitting AC power to the internal heater, and one or more heat generating elements of the internal heater. In the case of the H / A heater, the electric heater circuit may include connection point 426a on the first temperature control board 413 that receives AC power from the power distribution board 401, one of connection points 428a, 429a on the first temperature control board 413 that transmits AC power to the H / A heater, and one or more heat generating elements of the H / A heater. Connection point 422 or 426a where the first temperature control board 413 receives AC power may be considered a voltage or current source for the electric heater circuit. The heating element of the heater may be considered a resistive or electrical load driven by the voltage or current source.

[0058] In some cases, the electric heater circuit may additionally or alternatively include one or more power distribution components on the power distribution board 401. For example, the electric heater circuit may include one or more applicable fuses of the plurality of fuses 444. As another example, the electric heater circuit may include AC connection point 441. If a power distribution extension board 416 is used, the electric heater circuit may include the power distribution components of that board, including connection point 452 for receiving AC power from the power distribution board 401 (and corresponding connection point 451 on the power distribution board 401) and connection points 455, 456 for sending AC power to the second temperature control board 414 and the third temperature control board 415, respectively.

[0059] When used for heater diagnostic purposes, an electric heater circuit may be specific to a particular heater. For example, an electric heater circuit may be specific to a particular channel that carries AC power to the heater. An electric heater circuit may include a one-channel electric heater circuit. Additionally or alternatively, two or more heaters (e.g., for an H / A, a heated hose heater, and an applicator heater) may be supplied with AC power via a common electric heater circuit. For example, an electric heater circuit may be specific to a two-channel connection that supplies power to a heated hose / applicator pair (H / A). An electric heater circuit may include a two-channel electric heater circuit. Additionally or alternatively, all of the heaters connected to one temperature control board may share one electric heater circuit. For example, one electric heater circuit associated with the first temperature control board 413 may provide AC power to the first H / A heater, the second H / A heater, and the internal heaters of the melter and manifold. The electric heater circuit may include a four-channel or six-channel electric heater circuit.

[0060] Based on the current measurements 506 and / or voltage measurements 508, heater diagnostics 510 are performed to determine the status of the electrical heater circuit of the heater of interest (i.e., heater circuit status 512). Heater diagnostics 510 may be performed in real time or near real time, or heater diagnostics 510 may be performed at predetermined defined intervals (e.g., every 10 seconds, every 30 seconds, or every minute). Heater diagnostics 510 may be performed by one or more of the controller 36, control board 402, first, second, and third temperature control boards 413, 414, 415, or a remote device (e.g., remote device 38 of FIG. 1A).

[0061] The heater diagnostics 510 may include comparing the current measurements 506 to predefined threshold ranges of current (e.g., amperes). Similarly, the heater diagnostics 510 may include comparing the voltage measurements 508 to one or more predefined voltage threshold ranges. The voltage threshold ranges may relate to the presence / absence of voltage, voltage magnitude, AC line frequency, or a combination thereof. The heater diagnostics 510 may be performed based on the timing of the current measurements 506 and / or voltage measurements 508. For example, AC power to a heater may be intentionally turned on and off intermittently to maintain the heater at a temperature setpoint. The heater diagnostics 510 may include determining whether current is flowing or has ceased to flow through the electric heater circuit to the heater when the heater is intended to be deactivated.

[0062] The heater diagnostics 510 may be performed using multiple current measurements 506 and / or voltage measurements 508 over a period of time (i.e., over multiple measurements in a time series). For example, using multiple current measurements 506 and / or voltage measurements 508 over a time series, a predictive analysis may be performed on the current and / or voltage. The predictive analysis may include linear trend estimation, moving average, weighted moving average, or linear regression techniques, as some examples. Based on the time series of current measurements 506 or voltage measurements 508, a trend or forecast of when the current measurements 506 or voltage measurements 508 are expected to fall outside of a corresponding threshold range may be determined. Additionally or alternatively, a rate of change of the current measurements 506 or voltage measurements 508 over the time series may be determined and compared to a corresponding threshold range.

[0063] While heater diagnostics 510 can be performed based on only one of the current measurements 506 or the voltage measurements 508, in some cases it may be beneficial for heater diagnostics 510 to utilize both such measurements. For example, a current measurement 506 of zero amps could be caused by a problem with the heater's heating element or associated wiring, or it could be caused by any one of a variety of problems with the voltage supply, such as a blown fuse, a disconnected AC power connection from the power distribution board 401, or a fault in the external AC power source. However, by using both the current measurement 506 and the voltage measurement 508, heater diagnostics 510 can rule out the latter voltage supply problem as a potential cause of the current shortage (assuming that voltage measurement 508 actually indicates adequate voltage within the heater circuit). That is, heater diagnostics 510 can separate a problem with the voltage supply of the source from a problem with the load (e.g., heater element) attached to it, and vice versa. Additionally, heater diagnostics 510 may be performed using voltage measurements 508 for two or more of an indicator of voltage presence / absence, voltage magnitude, and AC line frequency.

[0064] The heater circuit status 512 is determined using the heater diagnostics 510. The heater circuit status 512 may indicate various fault conditions associated with the heater's electrical heater circuit. For example, the heater circuit status 512 may indicate that the current in the electrical heater circuit is outside of (e.g., above or below) a current threshold range. Similarly, the heater circuit status 512 may indicate that the voltage magnitude or AC line frequency in the heater circuit is outside of (e.g., above or below) a corresponding voltage threshold range. The heater circuit status 512 may indicate whether voltage is present or absent in the heater circuit.

[0065] Heater circuit status 512 may indicate additional fault conditions related to excess, insufficient, or absent (lack of) current or voltage. For example, heater circuit status 512 may indicate a blown / failed fuse, such as one of the fuses 444 on power distribution board 401, one fuse on one of the first, second, and third temperature control boards, or one fuse on power distribution extension board 406. A blown fuse may be associated with a lack of voltage and current measured by the respective voltage or current sensors.

[0066] As another example, the heater circuit status 512 may indicate an open heater element in the heater or a disconnected or broken wire to the heater from one of the first, second, and third temperature control boards 413, 414, 415. Such an open heater element or disconnected or broken wire may be associated with voltage being present at the voltage sensor and current through the heater element being too low (including no current or current very close to zero).

[0067] As another example, heater circuit status 512 may indicate an intermittent fault, including an intermittent wiring fault in the connection between one of the first, second, and third temperature control boards 413, 414, 415 and the associated heater, or an intermittent wiring fault in the AC voltage supply. Such intermittent faults may be associated with intermittent or fluctuating current and / or voltage readings. For example, current reading 506 and / or voltage reading 508 may indicate the presence of current and / or voltage at unintended times, either alone or in combination with the presence of current and / or voltage at intended times.

[0068] As another example, heater circuit status 512 may indicate an overload on the triac (alternating current triode) circuit of the heater circuit. An overload on the triac circuit may be associated with excessive current (e.g., current through the heater element). Heater circuit status 512 may indicate a shorted triac, which may be associated with current flowing at an unintended time. As another example, heater circuit status 512 may indicate an incorrect AC line frequency.

[0069] As another example, heater circuit status 512 may indicate a predicted failure state (including a probability interval of such predicted failure state). The predicted failure state may be based on predictive analysis performed in heater diagnostics 510. Relatedly, heater circuit status 512 may indicate a trend in current measurements 506 and / or voltage measurements 508 over a period of time. Accordingly, heater circuit status 512 may indicate a predicted time to failure of a component of adhesive dispensing apparatus 10, such as those associated with heater power and control. For example, the predicted time to failure may be for a heat generating element. The predicted fault state, trend, or predicted time of component failure may be utilized in performing preventative maintenance, repair, or replacement.

[0070] The heater circuit status 512 is not limited to fault conditions, but may also include general heater circuit conditions (e.g., intended or non-fault conditions). For example, the heater circuit status 512 may indicate that the current measurement 506 or voltage measurement 508 is within an acceptable threshold range. As a further example, the heater circuit status 512 may indicate that a predicted condition is within an acceptable threshold range, or that the current or voltage trend is flat or stable.

[0071] Based on the heater circuit status 512, a notification 514 may be generated. The notification 514 may indicate the heater circuit status 512. Some heater circuit statuses 512 may warrant a notification 514, while other heater circuit statuses may not. For example, a notification 514 may be generated when the heater circuit status 512 indicates a fault condition. However, a notification 514 may not be generated when the heater circuit status 512 indicates a non-fault condition.

[0072] The notification 514 may be in the form of an email or text message to an operator or other production facility personnel. The notification 514 may be in the form of an alert or message on the HMI device 34 of the adhesive dispensing apparatus 10 to notify the operator. The notification 514 may also be in the form of an audio alarm. The notification 514 may prompt the operator to take corrective action, particularly when the heater circuit condition 512 may cause damage to the adhesive dispensing apparatus 10. For example, excessive current flowing through a heater element may cause damage to the heater element.

[0073] The adhesive dispensing apparatus 10 and / or any external controller may initiate corrective action based on the heater circuit status 512, particularly when the heater circuit status 512 indicates a fault condition. For example, if a fault associated with the heater of the applicator or its attached heated hose is identified, the applicator may be automatically deactivated. Because temperature control and AC power supply to the heaters are independently distributed among the first, second, and third temperature control boards 413, 414, 415, corrective action (e.g., deactivation) may be taken with respect to only one or two of the first, second, and third temperature control boards 413, 414, 415 without affecting the functionality of the other boards. For example, if a damage fault condition associated with the second temperature control board 414 is indicated, the AC power supply to the second temperature control board 414 may be shut off, while AC power may still be supplied to the first and third temperature control boards 413, 415.

[0074] FIG. 6 illustrates an exemplary method flowchart of a method 600 for performing direct heater diagnostics, at least in part, with respect to a hot molten liquid dispensing system (e.g., adhesive dispensing apparatus 10 of FIGS. 1A-C, 2, and 3). Such diagnostics may relate to the heater generally, but may also relate to (and identify faults in) various components, subcomponents, and other elements associated with the heater of the hot molten liquid dispensing system, including, by way of example, heat-generating elements, heater circuits, conductors, wires, traces (e.g., PCB copper traces), connectors, fuses, power control switches, etc. The hot molten liquid dispensing system may include a melter (e.g., melt module 12 or melter subassembly 75) configured to melt a solid or semi-solid material into a hot molten liquid and a pump (e.g., pump 150) configured to pump the hot molten liquid to an associated applicator (e.g., applicator 144). The method may be performed, at least in part, by a controller of a high-temperature molten liquid dispensing system, such as controller 36 of FIG. 3, control board 402 of FIG. 4, one or more of first, second and third temperature control boards 413, 414, 415 of FIG. 4, or remote device 38 of FIG. 1A.

[0075] In step 602, at least one of a current measurement or a voltage measurement is received. The current measurement and / or voltage measurement may be associated with an electrical circuit configured to provide power (e.g., AC power) to a heater associated with a high temperature molten liquid dispensing system ("dispensing system"). The current measurement may be received from a current sensor (e.g., one of current sensors 438a, b, c of FIG. 4) disposed in the electrical circuit. The current measurement may indicate amperes flowing across the electrical circuit. The current measurement may include multiple current measurements. The current measurements may be taken at regular time intervals, and thus the current measurements may be a time series of multiple current measurements.

[0076] The voltage measurements may be received from a voltage sensor (e.g., one of voltage sensors 440a, b, c in FIG. 4) located in the electrical circuit. The voltage measurements may include one or more of voltage magnitude, presence / absence of voltage, and AC line frequency. The voltage measurements may include multiple voltage measurements. The voltage measurements may be taken at regular time intervals, so the voltage measurements may be a time series of multiple voltage measurements. The current measurements and voltage measurements may be taken simultaneously with each other or at different times.

[0077] The heater may include a heater in the applicator, a heater in a heated hose (e.g., heated hose 146) configured to carry the hot molten liquid to the applicator, a heater in the melter, or a heater in a manifold (e.g., manifold 140) of the dispensing system configured to direct the hot molten liquid from the pump to the applicator.

[0078] In step 604, the state of the electrical circuit (e.g., heater circuit state 512 in FIG. 5 ) is determined based on at least one of the current measurements or voltage measurements. In some embodiments, the state of the electrical circuit may be determined based on both the current measurements and the voltage measurements. The state of the electrical circuit may be determined according to heater diagnostics 510 in FIG. 5 . The state of the electrical circuit may be determined by comparing the current measurements and / or voltage measurements to predefined current threshold ranges and / or voltage threshold ranges, respectively. Determining the state of the electrical circuit may include performing predictive analysis on at least one of the current measurements or voltage measurements. For example, determining the state of the electrical circuit may include determining a rate of change of at least one of the current measurements or voltage measurements over a period of time. Determining the rate of change of the current measurements and / or voltage measurements may reveal trends in the current measurements and / or voltage measurements, from which predicted current measurements or voltage measurements may be determined.

[0079] The electrical circuit condition may include one or more of a blown fuse, a disconnected wire, a broken wire, an intermittent fault, a voltage magnitude outside a threshold range, an AC line frequency outside a threshold range, an open heater element in a heater, a current outside a threshold range, and a current occurring outside a predefined time.

[0080] In some embodiments, a dispensing system may include a power distribution module (e.g., power distribution board 402 of FIG. 4), a low-voltage control module (e.g., control board 402), and a temperature control module (e.g., first, second, or third temperature control boards 413, 414, 415). The temperature control module may be connected to a heater. The temperature control module may perform a temperature control function (e.g., a PID controller) for the heater based on temperature measurements (readings) from the heater's temperature sensor. The temperature control module may supply (and control) power to the heater. The operation (e.g., duty cycle) of the heater may be controlled by switching or intermittently supplying power to the heater. Current and voltage sensors may be located on the temperature control module. The temperature control module may implement or define, at least in part, the electrical circuitry that supplies power to the heater. For example, the temperature control module may have power connections for receiving power from the power distribution module and power connections for transmitting power to the heater. The electrical circuitry may include these two power connection points, the heater itself (e.g., heat generating element), and wire connections (e.g., power and temperature control connections) between the temperature control module and the heater. The electrical circuitry may include wire connections between the heater's temperature sensor and the temperature control module. The electrical circuitry may include power supply elements on the power distribution module, including power input from an external power source, power connection points to the temperature control module, and various fuses associated with powering the temperature control module and / or heater.

[0081] Method 600 may further include generating a notification (e.g., notification 514 of FIG. 5) based on the status of the electrical circuit. The notification may indicate the status of the electrical circuit. The notification may include an email, a text message, a notice or indicator on a user interface of the dispensing system or remote control system, or an audio alert.

[0082] Those skilled in the art will appreciate that the systems and methods disclosed herein may be implemented via a computing device, which may include, but is not limited to, one or more processors, a system memory, and a system bus that couples various system components, including coupling the processors to the system memory. For example, a computing device (e.g., a controller) may have one or more processors and memory that stores instructions that, when executed by the one or more processors, cause the computing device to perform one or more of the methods or techniques described herein, such as method 600.

[0083] For purposes of exemplary illustration, application programs and other executable program components, such as operating systems, are illustrated as separate blocks in the accompanying drawings herein. It is recognized, however, that such programs and components reside at various times in different storage components of the computing device and are executed by the computer's data processor(s). An implementation of the service software may be stored on or transmitted via some form of computer-readable media. Any of the disclosed methods may be performed by computer-readable instructions embodied on a computer-readable medium. A computer-readable medium may be any available medium that can be accessed by a computer. By way of example, and not limitation, computer-readable media may include "computer storage media" and "communications media." "Computer storage media" includes volatile and non-volatile, 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. Examples of computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical storage devices, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium usable to store desired information and accessible by a computer. Application programs, etc., and / or the storage media may be implemented at least in part on a remote system.

[0084] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Numerical ranges may be expressed as from "about" one particular value and / or to "about" another particular value. When a range is expressed in this manner, other embodiments include ranges from the one particular value and / or to the other particular value. Similarly, when a value is expressed as an approximation, by use of "about," it is to be understood that the one particular value also applies in other embodiments. Moreover, it is to be understood that each endpoint of such a range is valid both in relation to the other endpoint, and independently of the other endpoint.

[0085] Unless expressly stated otherwise, it is not intended that any method described herein be understood as requiring that its steps be performed in a particular order. Thus, if a method claim does not actually specify the order in which its steps must be followed, or if the claims or specification do not specifically state that the steps are limited to a particular order, no order is intended to be implied in any way. This applies to any possible implicit basis for interpretation, including matters of logic regarding the arrangement of steps or operational flow, the plain meaning derived from grammar or punctuation, and the number or type of embodiments described herein.

[0086] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the scope or spirit of the present application. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice disclosed therein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit being indicated by the following claims.

Claims

1. 1. A hot molten liquid dispensing system comprising: a melter configured to melt a solid or semi-solid material into a high temperature molten liquid; an electrical circuit configured to power a heater associated with the hot molten liquid dispensing system; A controller; Equipped with the electrical circuit includes at least one of a current sensor and a voltage sensor; The controller receiving at least one of a current measurement and a voltage measurement from the at least one of the current sensor and the voltage sensor; determining a state of the electrical circuit based on the at least one of the current measurement and the voltage measurement; It is configured as follows: A high temperature molten liquid dispensing system comprising:

2. the electrical circuit includes the current sensor and the voltage sensor; The controller further comprises: receiving the current measurements from the current sensors; receiving the voltage measurements from the voltage sensors; determining a state of the electrical circuit based on the current measurements and the voltage measurements; It is configured as follows:

10. The hot molten liquid dispensing system of claim 1.

3. The heater is in an applicator of the hot molten liquid dispensing system, in a heated hose connected to the hot molten liquid dispensing system, in the melter, or in a manifold of the hot molten liquid dispensing system configured to direct the hot molten liquid from a pump of the hot molten liquid dispensing system to the applicator.

10. The hot molten liquid dispensing system of claim 1.

4. The electrical circuit condition includes one or more of a blown fuse, a disconnected wire, a broken wire, an intermittent fault, a voltage magnitude outside a threshold range, an AC line frequency outside a threshold range, an open heater element of the heater, a current outside a threshold range, and a current occurring outside a predefined time.

10. The hot molten liquid dispensing system of claim 1.

5. Determining the state of the electrical circuit includes determining a rate of change of the at least one of the current measurement or the voltage measurement over time.

10. The hot molten liquid dispensing system of claim 1.

6. The electrical circuit further includes a temperature control module coupled to the heater and configured to provide power to the heater.

10. The hot molten liquid dispensing system of claim 1.

7. The at least one of the current sensor and the voltage sensor is located on the temperature control module.

7. The hot molten liquid dispensing system of claim 6.

8. the temperature control module includes a temperature controller; The temperature controller controls the power supplied to the heater based on a temperature signal received from a temperature sensor associated with the heater.

7. The hot molten liquid dispensing system of claim 6.

9. The voltage measurements include at least one of voltage magnitude, voltage presence / absence, or AC line frequency.

10. The hot molten liquid dispensing system of claim 1.

10. The controller is further configured to send a notification based on a state of the electrical circuit.

10. The hot molten liquid dispensing system of claim 1.

11. receiving at least one of a current measurement and a voltage measurement; A method comprising: the at least one of the current measurement and the voltage measurement is associated with an electrical circuit configured to power a heater associated with a high temperature molten liquid dispensing system; The method comprises: determining a state of the electrical circuit based on the at least one of the current measurement and the voltage measurement. The method further comprising:

12. receiving at least one of the current measurement and the voltage measurement includes receiving the current measurement and the voltage measurement; The state of the electrical circuit is determined based on the current measurements and the voltage measurements.

12. The method of claim 11 .

13. Determining the status of the electrical circuit includes determining the presence of one or more of a blown fuse, a disconnected wire, a broken wire, an intermittent fault, a voltage magnitude outside a threshold range, an AC line frequency outside a threshold range, an open heater element in the heater, a current outside a threshold range, and a current occurring outside a predefined time.

12. The method of claim 11 .

14. Determining the state of the electrical circuit includes determining a rate of change of the at least one of the current measurement or the voltage measurement over time.

12. The method of claim 11 .

15. Receiving the at least one of the current measurement and the voltage measurement includes receiving the at least one of the current measurement and the voltage measurement from at least one of a current sensor disposed on a temperature control module associated with the electrical circuit and a voltage sensor disposed on the temperature control module.

12. The method of claim 11 .

16. using a temperature controller to control the power supplied to the heater based on a temperature signal received from a temperature sensor associated with the heater.

12. The method of claim 11 further comprising:

17. generating a notification based on the state of the electrical circuit; 12. The method of claim 11 further comprising:

18. 1. A controller associated with a hot molten liquid dispensing system, comprising: one or more processors; a memory storing instructions that, when executed by the one or more processors, cause the controller to receive at least one of a current measurement and a voltage measurement and determine, based on the at least one of the current measurement and the voltage measurement, a state of an electrical circuit configured to supply power to a heater associated with the high temperature molten liquid dispensing system; Equipped with The at least one of the current measurement and the voltage measurement is associated with the electrical circuit. A controller characterized by:

19. The instructions, when executed by the one or more processors, further cause the controller to receive current measurements, receive voltage measurements, and determine a state of the electrical circuit based on the current measurements and the voltage measurements.

20. The controller of claim 18.

20. The at least one of the current measurement and the voltage measurement is received from at least one of a current sensor disposed on a temperature control module associated with the electrical circuit and a voltage sensor disposed on the temperature control module.

20. The controller of claim 18.

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