Buildup detection by applied power disturbance

Abstract

A method of monitoring a surface condition of a component in a thermal system includes heating the component to a steady-state, introducing a thermal disturbance to the component, determining a thermal response of at least one of the component, another system component, or the thermal system response in response to the thermal disturbance, and predicting the surface condition of the component based on a comparison between the thermal response and a reference response.

Description

Attorney Docket No.: 0100TS-000022-WO-POABUILDUP DETECTION BY APPLIED POWER DISTURBANCECROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to U.S. provisional application number 63 / 683,966 filed on August 16, 2024. The disclosure of the above application is incorporated herein by reference.FIELD

[0002] The present disclosure relates to a system and a method for monitoring a surface condition in a thermal system, and more particularly, to a system and a method for detecting and monitoring material buildup within a fluid flow system.BACKGROUND

[0003] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0004] Emissivity of a material is its effectiveness in emitting energy as thermal radiation. The emissivity of a surface of a system component can change over time due to, for example, deposits or scale buildups. In a thermal system including fluid conduits and a heater for heating the fluid flowing in the fluid conduits, the fluid may include chemicals or dissolved minerals and thus the thermal system is prone to buildup over time. The buildup causes changes in emissivity of the surfaces of the system components. When the system components are significantly degraded due to the changes in emissivity, system maintenance may be performed to replace the degraded components, resulting in unexpected downtime. To maintain the performance of the system components and / or reduce / inhibit downtime, preventive maintenance is generally scheduled for cleaning, refurbishment or replacement of components based on an expected rate of change, rather than based on actual needs. Therefore, the preventive maintenance may be performed too late or too early.

[0005] These issues related to material buildup within a fluid line system are addressed by the present disclosure.SUMMARY

[0006] This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features.Attorney Docket No.: 0100TS-000022-WO-POA

[0007] In one form, a method of monitoring a surface condition of a component in a thermal system includes: heating the component to a steady-state; introducing a thermal disturbance to the component; determining a thermal response of at least one of the component, another system component, or the thermal system in response to the thermal disturbance; and predicting the surface condition of the component based on a comparison between the thermal response and a reference response.

[0008] In variations of this method, which may be implemented individually or in any combination: the thermal disturbance is a change in thermal energy applied to the component; the change in thermal energy is a step change in power is to a heater that heats the component; the step change in power is an increased step change in a predetermined period of time; the step change in power is a decreased step change in a predetermined period of time; the surface condition is a material buildup on the component; the reference response is a nominal response that is generated when no material buildup exists on the component; the determining a thermal response of the component comprises measuring a temperature of the component or the another system component; the component is an outer sheath of a heater; the thermal system is a fluid line system, the another component is selected from a group consisting of an inlet of the fluid line system, an outlet of the fluid line system, a conduit of the fluid line system, a vessel housing of the fluid line system, and a structural support of the fluid line system; the thermal system includes a resistive element that heats the component, the resistive element being operable between a heating mode and a diagnostic mode; the resistive element is switched to the diagnostic mode before applying the thermal disturbance to the component; and the introducing the thermal disturbance to the component is performed in situ when the thermal system is in normal operation.

[0009] In another form, a method of monitoring a material buildup in a thermal system comprises: heating an outer sheath of a heater to a steady-state in a heating mode of the heater; providing a step change in power to the heater in a predetermined period of time in a diagnostic mode of the heater; determining a thermal response of the outer sheath in response to the step change in power to the heater; identifying a reference response of the outer sheath in response to the step change in power to the heater, wherein the reference response is a nominal response that corresponds to an absence of material buildup on the outer sheath of the heater; andAttorney Docket No.: 0100TS-000022-WO-POA predicting an amount of the material buildup on the outer sheath based on a comparison between the thermal response and the reference response.

[0010] In yet another form, a thermal system is provided that comprises a component and a thermal control system configured to: control a heater to heat the component to a steady state, control the heater to change a thermal energy to the component, determine a thermal response of the component in response to applying the thermal energy to the component, and predict an exterior surface condition of the component based on a comparison between the thermal response and a reference response.

[0011] In variations of this system, which may be implemented individually or in any combination: the thermal control system is configured to provide a step change in power to the component; the step change in power is an increased step change in a predetermined period of time; the step change in power is a decreased step change in a predetermined period of time; the surface condition is a material buildup on the component, the reference response being a nominal response that is generated when no material buildup exists on the component; and a resistive element is provided that heats the component, the resistive element being operable between a heating mode and a diagnostic mode.

[0012] Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.DRAWINGS

[0013] In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

[0014] FIG. 1 is a block diagram of a thermal system including a fluid line system and a thermal control system constructed in accordance with the teachings of the present disclosure;

[0015] FIG. 2 is a graph of a power applied to a heater of the thermal system to introduce a thermal disturbance to a component to be monitored;Attorney Docket No.: 0100TS-000022-WO-POA

[0016] FIG. 3 is an example reference thermal response of the component or a system component when no material buildup is present on the component to be monitored;

[0017] FIG. 4 is an example reference response of the component or a system component when a threshold amount of material buildup that would cause coking / fouling is present on the component; and

[0018] FIG. 5 is a flowchart of a method of monitoring a surface condition in a thermal system in accordance with the teachings of the present.

[0019] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.DETAILED DESCRIPTION

[0020] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0021] In general, the present disclosure provides a system and method that predict the presence or no-presence (e.g., absence) of a threshold amount of material buildup within a thermal system, such as a fluid line system, and further indicates maintenance action prior to reduced performance / efficiency of the fluid heating system based on the material buildup. This method includes introducing a thermal disturbance to a component to be monitored after the component is heated to a steady-state, determining a thermal response of the component or an adjacent system component in response to the thermal disturbance, and then predicting the surface condition of the component based on a comparison between the determined thermal response and a reference response.

[0022] For example, in a fluid line system, coking in a heater or other system components of the fluid line system can increase the emissivity and reduce the convective heat transfer rate, thereby causing the heaters to operate at higher temperatures and with increased energy consumption. The system and method of the present disclosure can detect the presence of coking on the heater or another system component in the thermal system and alert an operator and / or a system controller of the detected condition. Furthermore, the system and method can more accurately localize the material buildup on various components of the fluid line system, therebyAttorney Docket No.: 0100TS-000022-WO-POA enabling the operator and / or the system controller to accommodate for and / or remedy the material buildup when implementing control parameters for the fluid line system.

[0023] Referring to FIG. 1 , a thermal system 20 constructed in accordance with the teachings of the present disclosure includes a fluid line system 22 and a thermal control system 24. The fluid line system 22 may be (or may be part of) a semiconductor processing system, a heat exchanger, a circulation heater, or a boiler. The fluid line system 22 may include a vessel housing 26 defining a fluid chamber, and a plurality of fluid conduits, including an inlet 28 and an outlet 30 to allow a fluid to flow in and out of the fluid chamber. The fluid line system 22 further includes a heater 32, a component 34, and a plurality of temperature sensors 36. The heater 32 is configured to operate with the thermal control system 24 to monitor a surface condition of the component 34 of the fluid line system 22. The component 34 may be a wall of the fluid line system 22 (such as a wall of the vessel housing 28, a wall of the inlet 28, a wall of the outlet 30), a surface or an outer sheath of the heater 32.

[0024] The heater 32 may be a part of a heating apparatus that provides primary heating to the fluid contained in the fluid line system 22 or may be a separate heater for the purpose of monitoring a surface condition of the component 34. If the heater 32 is a part of the heating apparatus that provides the primary heating to the fluid contained in the fluid line system 22, the heater 32 may be operated in at least one of an operating mode in which the heater 32 provides primary heating to the fluid according to predetermined system parameters and a diagnostic mode in which the heater 32 is operated to apply a thermal disturbance to the component 34 to be monitored for the purpose of determining material buildup on the component 34. The heater 32 may be integrated in the component 34 to be monitored or disposed adjacent to the component 34. As an example, the heater 32 may be an open coil heater. When the surface conditions of more components are to be monitored, more heaters may be provided proximate the components to perform diagnosis of individual components.

[0025] The heater 32 may include a resistive heating element that is built into the component 34 or that is disposed externally from the component 34 and is configured to provide thermal energy to the component 34. As used herein, “providing thermal energy to the component 34” refers to increasing or decreasing thermal energy provided to a surface of the component 34 and / or an environment proximate to (i.e., adjacent and / or near) the component 34. As an example, increasing theAttorney Docket No.: 0100TS-000022-WO-POA thermal energy provided to the component 34 may include heating a surface of the component 34 and / or an environment proximate the component 34. As another example, decreasing the thermal energy provided to the component 12 may include cooling a surface of the component 34 and / or an environment proximate the component 34.

[0026] The thermal control system 24 is configured to monitor a surface condition in the fluid line system 22 by monitoring a surface condition of the component 34. The thermal control system 26 includes a heater control module 40, a thermal response determination module 42, a comparison and predication module 44, a surface condition reference table database 46, and an alarm module 48. It should be readily understood that any one of the modules, systems, and / or databases of the thermal control system 24 can be provided at the same location or distributed at different locations (e.g., via one or more edge computing devices) and communicably coupled accordingly. The thermal control system 24 and the temperature sensors 36 may be connected by wires, or may be communicably coupled using a wired communication protocol and / or a wireless communication protocol (e.g., a Bluetooth®- type protocol, a cellular protocol, a wireless fidelity (Wi-Fi)-type protocol, a near-field communication (NFC) protocol, an ultra-wideband (UWB) protocol, among others).

[0027] The heater control module 40 is electrically connected to the heater 32 for controlling operation of the heater 32. When the heater 32 is a part of the heating apparatus that provides primary heating to the fluid contained in the fluid line system 22, the heater control module 40 is also configured to control the normal heating operation of the heater 32 according to system parameters. The thermal response determination module 42 is electrically connected to the temperature sensors 36 for determining a thermal response of the component 34, or a system component, in response to a thermal energy applied by the heater 32 to the component 34 to be monitored.

[0028] The plurality of temperature sensors 36 may be built into the component 34 or disposed externally from the component 34 for measuring temperatures of the surface and / or environment of the component 34. As an example, the temperature sensors 36 may include, but are not limited to: thermocouples, resistance temperature detectors (RTDs), infrared sensors, and / or other conventional temperature sensing devices. In one form, the temperature sensors 36 are “two-wire” heaters that are built into the component 12. The two-wire heaters include resistiveAttorney Docket No.: 0100TS-000022-WO-POA heating elements that function as heaters and as temperature sensors with only two lead wires operatively connected to the heating element rather than four. Such two- wire capability is disclosed in, for example, U.S. Patent No. 7,196,295, which is commonly assigned with the present application and incorporated herein by reference in its entirety. Typically, in a two-wire system, the resistive heating elements are defined by a material that exhibits a varying resistance with varying temperature such that an average temperature of the resistive heating element is determined based on a change in resistance of the resistive heating element. In one form, the resistance of the resistive heating element is calculated by first measuring the voltage across and the current through the heating elements and then, using Ohm’s law, the resistance is determined. The resistive heating element may be defined by a relatively high temperature coefficient of resistance (TCR) material, a negative TCR material, or in other words, a material having a non-linear TCR.

[0029] The surface condition of the component 34 may be an amount of material buildup or deposits on a surface of the component 34. The material buildup or deposits affect the thermal characteristics of the surface of the component 34, such as emissivity of the component 34, thermal coupling between multiple zones of the component 34, thermal gains of the component 34, an electric resistance-temperature correlation of the component 34, and gas convective coupling of the component 34. The thermal control system 24 is configured to monitor changes in the thermal characteristics of the surface of the component 34 and thereby predict the state and / or amount of the material buildup and deposits on the surface of the component 34.

[0030] The heater control module 40 is configured to control an operation of the heater 32. The heater control module 40 may include a power supply and one or more power converter circuits to provide power to the heater 32, which in turn, provides the thermal energy to the component 34. If the heater 32 is a part of the heating apparatus that provides primary heating to the fluid line system, the heater control module 40 is configured to control and switch the heater 32 to operate between a heating mode and a diagnostic mode. The heater control module 40 may switch the heater 32 from the heating mode to the diagnostic mode at a predetermined interval to perform diagnosis for a predetermined period of time to predict the surface condition of the component. Therefore, the diagnosis (introducing thermal disturbance and determining and comparing thermal response to predict material buildup) is performed in situ when the thermal system is in normal operation.Attorney Docket No.: 0100TS-000022-WO-POA

[0031] Accordingly, to perform the functionality described herein, the heater control module 40 may include one or more processors configured to execute instructions stored for in a nontransitory computer-readable medium (e.g., a randomaccess memory (RAM) and / or a read-only memory (ROM)) and to control the power converter circuits and the power supply.

[0032] In one form, the heater control module 40 first controls the heater 32 to operate in the heating mode and to heat the component 34 to a steady state. After that, the heater control module 40 switches the heater 32 to operate in the diagnostic mode. In the diagnostic mode, the heater 32 is supplied with a step change in power in a predetermined period of time that is at least the time constant of the thermal system nominal response. The step change in power causes the heater 32 to provide an increased or decreased thermal energy to the component 34, thereby introducing a thermal disturbance to the component 34 and the surrounding environment and making the component 34 and the surrounding environment no longer in a steady state. While FIG. 2 shows the step change in power is a step increase in power, it is understood that the step change in power can be a step decrease in power since the step decrease in power also introduces a thermal disturbance to the component 34 and the surrounding environment and changes the steady state.

[0033] Referring back to FIG. 1 , the thermal response determination module 42 is configured to determine a thermal response of the component 34 or a system component after the thermal disturbance is introduced in the fluid line system 22 of the thermal system 20. The thermal response determination module 42 is configured to receive signals from the temperature sensors 36 and then determine a thermal response of the component 34 or a surrounding environment of the component, and / or another system component of the fluid line system, based on the signals obtained by the temperature sensors 36. The temperature sensors 36 measure the temperature at the component 34 or surrounding environment. As such, a temperature change, e.g., the thermal response, in response to the thermal disturbance can be determined. In one form, the thermal response of the component 12 refers to the rate at which the component 34 dissipates the thermal energy to the surrounding environment after the thermal energy is provided to the component 34. As an example, the thermal response determination module 42 is configured to determine a rate at which the component 34 dissipates the thermal energy as aAttorney Docket No.: 0100TS-000022-WO-POA function of a temperature change over a given time period. In some forms, the thermal response may be determined when the temperature of the component 34 is equal to a predetermined temperature and / or during a predetermined time period. By way of example, the thermal response may be determined using measured parameters of a system (e.g., a voltage, current, electric resistance, and / or parameters of the heater 14 when providing the thermal energy).

[0034] Referring to FIGS. 1 , 3, and 4, the surface condition reference table database 46 stores one or more reference responses of the component 34. The one or more reference responses of the component 34 may include one that represents a thermal response or characteristics of the surface of component 34 when there is no material buildup on the surface of the component 12, as shown in FIG. 3, or one that represents a thermal response or characteristics of the component 34 when a threshold amount of material buildup is formed on the surface of the component 34, indicating possible coking / fouling, as shown in FIG. 4.

[0035] The surface condition reference table may be a lookup table that correlates various thermal characteristics of the component 34 to various empirically obtained surface conditions of the component 34. As such, an operator may generate the lookup table by depositing various known amounts and / or distribution patterns of materials onto the component 34 and comparing, for example, the thermal response change for the known amounts of materials to the reference response.

[0036] Referring back to FIG. 1 , the comparison and prediction module 44 is configured to compare the determined thermal response and a reference response and predict the surface condition based on the comparison. The comparison and prediction module 44 may compare the determined thermal response with a first reference thermal response representing no buildup (as shown in FIG. 3), and / or with a second reference thermal response representing a threshold amount of buildup (as shown in FIG. 4) that would cause possible performance degradations due to coking / fouling. Based on the comparison, the comparison and prediction module 44 can predict whether the characteristic change of the surface of the component 34 is “normal” (i.e., below the threshold amount of buildup) or “abnormal” (i.e., above the threshold amount of buildup). It should be understood that the thermal response determination module 42 may characterize the component 34 using various other qualitative and / or quantitative properties that relate to the amount of material buildup on the surface of the component 34.Attorney Docket No.: 0100TS-000022-WO-POA

[0037] The alarm module 48 is configured to provide an alert to an operator when the comparison and prediction module 44 predicts that the presence of material buildup on the surface of the component 34 reaches the threshold amount. The alarm module 40 may include various visual interfaces (e.g., a touchscreen, a display monitor, an augmented reality device, and / or a plurality of light-emitting diodes (LEDs)), auditory interfaces (e.g., a speaker circuit for auditorily outputting messages corresponding to the material buildup), and / or haptic interfaces (e.g., a vibration motor circuit that vibrates when the material buildup is greater than a threshold value).

[0038] Referring to FIG. 5, a method 60 of monitoring a surface condition in a thermal system 20 starts with step 62. The component 34 is first heated to a steady-state at step 64. When the component 34 reaches a steady-state, the heater is switched from the heating mode to the diagnostic mode to perform diagnosis at step 66. In the diagnostic mode, the heater is supplied with a step power for a predetermined period of time at step 68. The step power causes the heater to introduce a thermal disturbance to the steady state of the component. A thermal response of the component or another system component in response to the thermal disturbance is determined at step 70. The thermal response is compared with a reference response at step 72.

[0039] The reference response may be a first nominal reference that is generated when no material buildup exists on the surface of the component 34, or a second nominal reference that is generated when a threshold amount of material buildup exists on the surface of the component 34. When the thermal response deviates from a reference response (i.e., the first nominal reference) or matches a predetermined reference response (i.e., the second nominal reference) representing a threshold amount of buildup, it is determined that a threshold amount of material buildup exist on a surface of the component at step 74. The alarm module then generates an alert at step 76. After the diagnosis, the heater is switch to the heating mode to perform normal heating operation at step 78. The method ends at step 80.

[0040] Unless otherwise expressly indicated herein, all numerical values indicating mechanical / thermal properties, compositional percentages, dimensions and / or tolerances, or other characteristics are to be understood as modified by the word “about” or "approximately" in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice, material, manufacturing, and assembly tolerances, and testing capability.Attorney Docket No.: 0100TS-000022-WO-POA

[0041] As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”

[0042] In this application, the term “controller” and / or “module” may refer to, be part of, or include: an Application Specific Integrated Circuit (ASIC); a digital, analog, or mixed analog / digital discrete circuit; a digital, analog, or mixed analog / digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; other suitable hardware components (e.g., op amp circuit integrator as part of the heat flux data module) that provide the described functionality; or a combination of some or all of the above, such as in a system-on-chip.

[0043] The term memory is a subset of the term computer-readable medium. The term computer-readable medium, as used herein, does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave); the term computer-readable medium may therefore be considered tangible and non-transitory. Non-limiting examples of a non-transitory, tangible computer-readable medium are nonvolatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask readonly circuit), volatile memory circuits (such as a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (such as an analog or digital magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray Disc).

[0044] The apparatuses and methods described in this application may be partially or fully implemented by a special purpose computer created by configuring a general-purpose computer to execute one or more particular functions embodied in computer programs. The functional blocks, flowchart components, and other elements described above serve as software specifications, which can be translated into the computer programs by the routine work of a skilled technician or programmer. It should be noted that one or more functions can be performed online or offline, and may be performed in real-time, and can be performed locally (e.g., at the thermal system 20) or at a remote location (e.g., cloud processing).Attorney Docket No.: 0100TS-000022-WO-POA

[0045] The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.

Claims

Attorney Docket No.: 0100TS-000022-WO-POACLAIMSWhat is claimed is:1 . A method of monitoring a surface condition of a component in a thermal system, the method comprising: heating the component to a steady-state; introducing a thermal disturbance to the component; determining a thermal response of at least one of the component, another system component, or the thermal system in response to the thermal disturbance; and predicting the surface condition of the component based on a comparison between the thermal response and a reference response.

2. The method according to Claim 1 , wherein the thermal disturbance is a change in thermal energy applied to the component.

3. The method according to Claim 2, wherein the change in thermal energy is a step change in power to a heater that heats the component.

4. The method according to Claim 3, wherein the step change in power is an increased step change in a predetermined period of time.

5. The method according to Claim 3, wherein the step change in power is a decreased step change in a predetermined period of time.

6. The method according to Claim 1 , wherein the surface condition is a material buildup on the component.

7. The method according to Claim 1 , wherein the reference response is a nominal response that is generated when no material buildup exists on the component.

8. The method according to Claim 1 , wherein the determining a thermal response of the component comprises measuring a temperature of the component or the another system component.Attorney Docket No.: 0100TS-000022-WO-POA9. The method according to Claim 1 , wherein the component is an outer sheath of a heater.

10. The method according to Claim 1 , wherein the thermal system is a fluid line system, the another component is selected from a group consisting of an inlet of the fluid line system, an outlet of the fluid line system, a conduit of the fluid line system, a vessel housing of the fluid line system, and a structural support of the fluid line system.11 . The method according to Claim 1 , wherein the thermal system includes a resistive element that heats the component, the resistive element being operable between a heating mode and a diagnostic mode.

12. The method according to claim 11 , wherein the resistive element is switched to the diagnostic mode before applying the thermal disturbance to the component.

13. The method according to Claim 1 , wherein the introducing the thermal disturbance to the component is performed in situ when the thermal system is in normal operation.

14. A method of monitoring a material buildup in a thermal system, the method comprising: heating an outer sheath of a heater to a steady-state in a heating mode of the heater; providing a step change in power to the heater in a predetermined period of time in a diagnostic mode of the heater; determining a thermal response of the outer sheath in response to the step change in power to the heater; identifying a reference response of the outer sheath in response to the step change in power to the heater, wherein the reference response is a nominal response that corresponds to an absence ofmaterial buildup on the outer sheath of the heater; andAttorney Docket No.: 0100TS-000022-WO-POA predicting an amount of the material buildup on the outer sheath based on a comparison between the thermal response and the reference response.

15. A thermal system comprising: a component; and a thermal control system configured to: control a heater to heat the component to a steady state; control the heater to change a thermal energy to the component; determine a thermal response of the component in response to applying the thermal energy to the component; and predict an exterior surface condition of the component based on a comparison between the thermal response and a reference response.

16. The system according to Claim 15, wherein the thermal control system is configured to provide a step change in power to the component.

17. The system according to Claim 16, wherein the step change in power is an increased step change in a predetermined period of time.

18. The system according to Claim 16, wherein the step change in power is a decreased step change in a predetermined period of time.

19. The system according to Claim 16, wherein the surface condition is a material buildup on the component, the reference response being a nominal response that is generated when no material buildup exists on the component.

20. The system according to Claim 16, further comprising a resistive element that heats the component, the resistive element being operable between a heating mode and a diagnostic mode.

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