Heater bundles for thermal gradient compensation

Abstract

To provide a heater system including a heater bundle.SOLUTION: A heater bundle includes a plurality of heater assemblies, at least one of the heater assemblies including a plurality of heater units, at least one of the heater units defining at least one independently controlled heating zone. A thermal provision is configured to modify a thermal conductance along a length of the at least one heater assembly to compensate for non-uniform temperatures within at least one heater unit. The heater bundle includes a power supply device including a controller configured to modulate power to the independently controlled heating zone through the power conductors based on the determined temperature to provide a desired power output along a length of at least one heater assembly.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Cross - Reference to Related Applications This application is a continuation - in - part of U.S. Patent Application No. 16 / 272,668, filed on February 11, 2019, titled "Heater Bundle for Adaptive Control", which is a continuation of U.S. Patent Application No. 15 / 058,838, filed on March 2, 2016, and now U.S. Patent No. 10,247,445. The entire content of the above disclosure is incorporated herein by reference in its entirety.

[0002] The present disclosure relates to electric heaters, and more particularly, to heaters for heating a fluid such as a fluid within a heat exchanger.

Background Art

[0003] The description of this section merely provides background information related to the present disclosure and does not constitute prior art.

[0004] The fluid heater may be in the form of a cartridge heater having a rod configuration for heating a fluid flowing along or through the outer surface of the cartridge heater. The cartridge heater may be disposed inside a heat exchanger for heating a fluid flowing through the heat exchanger. If the cartridge heater is not properly sealed, moisture and fluid may enter the cartridge heater, contaminating the insulating material that electrically insulates the resistance heating element from the metal sheath of the cartridge heater, resulting in electrical breakdown and, consequently, heater failure. Moisture may also cause a short - circuit between the power conductor and the outer metal sheath. Failure of the cartridge heater can cause costly downtime of the device using the cartridge heater.

Summary of the Invention

Problems to be Solved by the Invention

[0005] [Means for solving the problem]

[0006] This section provides a general overview of this disclosure and is not a comprehensive disclosure of its entire scope or all of its features.

[0007] This disclosure provides a heating system including a heating bundle, the heating bundle comprising a plurality of heating assemblies, at least one of the heating assemblies comprising a plurality of heating units, at least one of which is an independently controlled heating region. At least one heat supply unit is configured to change the thermal conductance along the length of at least one heating assembly to compensate for non-uniform temperatures. A plurality of power conductors are electrically connected to the heating units and means for determining the temperature are provided. The power supply unit includes a controller configured to modulate power to the independently controlled heating region via the power conductors based on the determined temperature in order to provide a desired power output along the length of at least one heating assembly.

[0008] In a variation of this heating system, which can be implemented individually or in any combination, at least one heating unit is an end heating unit located at the end of at least one heating assembly, the heat supply unit increases the thermal conductance within at least one heating unit, the at least one heat supply unit comprises a conductive sleeve adjacent to the resistive heating element of at least one heating unit, the conductive sleeve having a higher thermal conductivity than the material surrounding the resistive heating element, each heating unit comprises an outer sheath, and at least one heat supply unit comprises at least one heating unit having an outer sheath having a greater thickness than the outer sheath of an adjacent heating unit, each heating unit comprises an outer sheath, and at least one heat supply unit comprises at least one heating unit having an outer sheath having a higher thermal conductivity than the outer sheath of an adjacent heating unit, and at least one heat supply unit comprises at least two power conductors operably connected to at least one heating unit, at least one of the two power conductors adjacent to at least one heating unit Having a greater thickness, at least one heat supply unit comprises at least two power conductors operably connected to at least one heating unit, at least one of the two power conductors having a higher thermal conductivity in proximity to at least one heating unit, at least one heat supply unit comprising at least one heating unit having a shorter length than the length of adjacent heating units, at least one heating assembly defining the spacing between adjacent heating units, at least one heat supply unit comprising at least one of the spacings being different between heating units, spacers being placed between adjacent heating units, at least one heat supply unit comprising a spacer thicker than other spacers between at least one heating unit and adjacent heating units, at least one heat supply unit comprising a plurality of power conductors whose cross-sectional area between adjacent heating units is smaller than their nominal cross-sectional area, at least one heating assembly comprising resistance heating elements, at least one of the resistance heating elements functioning as a sensor, and two or more of the heating units defining at least one independently controlled heating region.

[0009] In another embodiment of the present disclosure, the heating system includes a heating bundle comprising a plurality of heating assemblies, wherein at least one of the heating assemblies comprises a plurality of heating units, and at least one heating unit is an independently controlled heating region; at least one heat supply unit configured to modify the thermal conductance along the length of at least one heating assembly to compensate for non-uniform temperatures; and a plurality of power conductors electrically connected to the heating units. Means are provided for determining at least one of heating conditions and heating requirements, and the power supply unit includes a controller configured to modulate power to the independently controlled heating region of at least one heating unit via the power conductors to provide a desired power output along two or more lengths of the heating assembly, based on at least one of the heating conditions and heating requirements.

[0010] In a variation of this heating system, which can be implemented individually or in any combination, at least one heating unit is an end heating unit located at the end of at least one heating assembly, the heat supply unit increases the thermal conductance within at least one heating unit, at least one of the heating conditions and requirements is selected from the group consisting of heating unit lifespan, heating unit reliability, heating unit size, heating unit cost, local heater flux, heating unit characteristics and operation, and overall power output, and two or more of the heating units define at least one independently controlled heating region.

[0011] In yet another embodiment, a heating system is provided, comprising: a heating assembly comprising a plurality of heating units, wherein at least one heating unit is an independently controlled heating region; at least one heat supply unit configured to modify the thermal conductance along the length of the heating assembly to compensate for non-uniform temperatures; a plurality of power conductors electrically connected to the heating units; and a power supply unit including a controller configured to modulate power to the independently controlled heating region of at least one heating unit via the power conductors based on at least one of heating conditions and heating requirements, in order to provide a desired power output along the length of the heating assembly.

[0012] In a variation of this heating system, which can be implemented individually or in any combination, at least one heating unit is an end heating unit located at the end of a heating assembly, and means are provided for determining the temperature and means are provided for determining heating conditions or heating requirements, two or more heating units define at least one independently controlled heating region, and the heating assembly includes resistive heating elements, at least one of which functions as a sensor.

[0013] In yet another variation, the heating system is included in a device for heating a fluid. The device comprises a sealed housing that defines an internal chamber and has a fluid inlet and a fluid outlet, and the heating assembly is located within the internal chamber of the housing. The heating assembly is adapted to provide a responsive heat distribution to the fluid in the housing. The heat distribution responds based on an implementation of the heat supply unit as illustrated and described herein.

[0014] Further areas of application will become apparent from the descriptions provided herein. It should be understood that the descriptions and specific examples are for illustrative purposes only and are not intended to limit the scope of this disclosure.

[0015] To ensure that this disclosure can be fully understood, various forms thereof, given as examples, are described herein with reference to the attached drawings. [Brief explanation of the drawing]

[0016] [Figure 1] This is a perspective view of a heated bundle configured in accordance with the teachings of this disclosure. [Figure 2] This is a perspective view of the heating assembly of the heating bundle shown in Figure 1, as taught in this disclosure. [Figure 3] This is a perspective view of a modified heating assembly of the heating bundle of Figure 1 according to the teachings of this disclosure. [Figure 4] Figure 3 is a perspective view of the heating assembly as taught in this disclosure, with the outer sheath of the heating assembly removed for clarity. [Figure 5] Figure 3 is a perspective view of the core of the heating assembly as taught in this disclosure. [Figure 6] Figure 1 is a perspective view of a heat exchanger including a heating bundle as taught in the present disclosure, the heating bundle being partially disassembled from the heat exchanger to expose the heating bundle for illustrative purposes. [Figure 7] This is a block diagram of a method for operating a heating system including a heating bundle configured in accordance with the teachings of this disclosure. [Figure 8] This is a perspective view of a heating assembly including a heat supply unit as taught in this disclosure. [Figure 9] This is a cross-sectional view of the heating assembly along line 9-9 in Figure 8, as taught in this disclosure. [Figure 10] This is a cross-sectional view of the heating assembly along line 10-10 in Figure 8, as taught in this disclosure. [Figure 11] This is a perspective view of a heating assembly including another heat supply unit as taught in this disclosure. [Figure 12] This is a cross-sectional view of the heating assembly along line 12-12 in Figure 11, as taught in this disclosure. [Figure 13] This is a cross-sectional view of the heating assembly along line 13-13 in Figure 11, as taught in this disclosure. [Figure 14] Perspective view of a heating assembly including another heat supply unit according to the teachings of the present disclosure. [Figure 15] Side view of the heat supply unit of the heating assembly of FIG. 14 according to the teachings of the present disclosure. [Figure 16] Perspective view of a heating assembly including a heat supply unit according to the teachings of the present disclosure. [Figure 17] Perspective view of a heating assembly including a heat supply unit according to the teachings of the present disclosure. [Figure 18] Cross-sectional view of the heating assembly along line 18-18 of FIG. 17 according to the teachings of the present disclosure. [Figure 19] Cross-sectional view of the heating assembly along line 19-19 of FIG. 17 according to the teachings of the present disclosure. [Figure 20] Perspective view of a heating assembly including a heat supply unit according to the teachings of the present disclosure.

Mode for Carrying Out the Invention

[0017] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way.

[0018] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its applications, or uses.

[0019] Referring to FIG. 1, a heating system constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral 10. The heating system 10 includes a heating bundle 12 and a power supply unit 14 electrically connected to the heating bundle 12. The power supply unit 14 includes a controller 15 for controlling the power supply to the heating bundle 12. As used herein, a "heating bundle" refers to a heating device that includes two or more physically separate heating devices that can be independently controlled. Thus, if one of the heating devices within the heating bundle fails or deteriorates, the remaining heating devices within the heating bundle 12 can continue to operate.

[0020] In one embodiment, the heating bundle 12 includes a mounting flange 16 and a plurality of heating assemblies 18 fixed to the mounting flange 16. The mounting flange 16 includes a plurality of openings 20 through which the heating assemblies 18 extend. In this embodiment, the heating assemblies 18 are arranged parallel to each other, but it should be understood that alternative positions / arrangements of the heating assemblies 18 are within the scope of this disclosure.

[0021] As further shown, the mounting flange 16 includes a plurality of mounting holes 22. By using screws or bolts (not shown) passing through the mounting holes 22, the mounting flange 16 can be mounted to the wall of a container or pipe (not shown) that carries the fluid to be heated. At least a portion of the heating assembly 18 is immersed in the fluid inside the container or pipe to heat the fluid in this form of the disclosure.

[0022] Referring to Figure 2, one embodiment of the heating assembly 18 may be in the form of a cartridge heater 30. The cartridge heater 30 is generally a tubular heater comprising a core 32, a resistive heating wire 34 wound around the core 32, a metal sheath 36 enclosing the core 32 and the resistive heating wire 34 internally, and an insulating material 38 filling the space within the metal sheath 36, which electrically insulates the resistive heating wire 34 from the metal sheath 36 and conducts heat from the resistive heating wire 34 to the metal sheath 36. The core 32 may be made of ceramic. The insulating material 38 may be compressed magnesium oxide (MgO). Multiple power conductors 42 penetrate the core 32 longitudinally and are electrically connected to the resistive heating wire 34. The power conductors 42 also extend through end pieces 44 that seal the metal sheath 36. The power conductors 42 are connected to a power supply 14 (shown in Figure 1), which supplies power to the resistive heating wire 34. Figure 2 shows only two power conductors 42 extending through the end piece 44, but three or more power conductors 42 may extend through the end piece 44. The power conductors 42 may also be in the form of conductive pins. Various structures of the cartridge heater, as well as further structural and electrical details, are described in detail in U.S. Patents 2,831,951 and 3,970,822, which are assigned in common with this application and whose entire contents are incorporated herein by reference. Therefore, it should be understood that the forms shown herein are merely illustrative and should not be construed as limiting the scope of this disclosure.

[0023] Alternatively, multiple pairs of resistive heating wires 34 and power conductors 42 can be used to form multiple heating circuits that can be independently controlled to enhance the reliability of the cartridge heater 30. Therefore, if one of the resistive heating wires 34 fails, the remaining resistive heating wires 34 can continue to generate heat without causing failure of the entire cartridge heater 30 and without incurring downtime for the expensive machine.

[0024] Referring to Figures 3 to 5, the heating assembly 50 may be in the form of a cartridge heater having the same configuration as in Figure 2, except for the number of cores and power conductors used. More specifically, each heating assembly 50 includes a plurality of heating units 52 and an outer metal sheath 54 enclosing the plurality of heating units 52, along with a plurality of power conductors 56. An insulating material (not shown in Figures 3 to 5) is provided between the plurality of heating units 52 and the outer metal sheath 54 to electrically insulate the heating units 52 from the outer metal sheath 54. Each of the plurality of heating units 52 includes a core 58 and a resistive heating element 60 surrounding the core 58. The resistive heating element 60 of each heating unit 52 can define one or more heating circuits for defining one or more heating regions 62.

[0025] In this embodiment, each heating unit 52 defines one heating region 62, and the multiple heating units 52 within each heating assembly 50 are aligned along the longitudinal direction X. Thus, each heating assembly 50 defines multiple heating regions 62 aligned along the longitudinal direction X. The core body 58 of each heating unit 52 defines multiple through holes / openings 64 to allow the power supply conductor 56 to pass through. The resistive heating elements 60 of the heating unit 52 are connected to the power supply conductor 56, which is connected to the power supply unit 14. The power supply conductor 56 supplies power from the power supply unit 14 to the multiple heating units 52. By properly connecting the power supply conductor 56 to the resistive heating elements 60, the resistive heating elements 60 of the multiple heating units 52 can be independently controlled by the controller 15 of the power supply unit 14. Thus, a failure of one resistive heating element 60 for a particular heating region 62 does not affect the proper functioning of the remaining resistive heating elements 60 for the remaining heating regions 62. Furthermore, the heating unit 52 and the heating assembly 50 may be replaceable to facilitate repair or assembly.

[0026] In this embodiment, six power conductors 56 are used for each heating assembly 50 to supply power to five independent electric heating circuits on five heating units 52. Alternatively, the six power conductors 56 may be connected to a resistive heating element 60 to define three completely independent circuits on the five heating units 52. It is possible to have any number of power conductors 56 to form any number of independently controlled heating circuits and independently controlled heating regions 62. For example, seven power conductors 56 can be used to provide six heating regions 62. Eight power conductors 56 can be used to provide seven heating regions 62.

[0027] The power conductor 56 may include multiple power and power return conductors, multiple power return conductors and a single power conductor, or multiple power conductors and a single power return conductor. If the number of heating regions is n, the number of power conductors and return conductors is n+1.

[0028] Alternatively, a greater number of electrically distinct heating regions 62 can be created by multiplexing, polarity-sensitive switching, and other circuit topologies by the controller 15 of the power supply unit 14. The use of multiplexing or various arrangements of thermal arrays to increase the number of heating regions in the cartridge heater 30 for a given number of power conductors (e.g., a cartridge heater having six power conductors for 15 or 30 regions) is disclosed in U.S. Patents 9,123,755, 9,123,756, 9,177,840, 9,196,513 and their related applications, which are assigned in common with this application and whose contents are incorporated herein by reference in their entirety.

[0029] This structure allows each heating assembly 50 to include multiple heating regions 62 that can be independently controlled to vary the power output or heat distribution along the length of the heating assembly 50. A heating bundle 12 includes multiple such heating assemblies 50. Thus, the heating bundle 12 provides multiple heating regions 62 and a tuned heat distribution for heating a fluid flowing through the heating bundle 12 to suit a particular application. The power supply 14 can be configured to modulate power to each of the independently controlled heating regions 62.

[0030] For example, a heating assembly 50 can define m heating regions, and a heating bundle may contain k heating assemblies 50. Thus, a heating bundle 12 can define m × k heating regions. The multiple heating regions 62 within the heating bundle 12 can be individually and dynamically controlled according to heating conditions and / or heating requirements, including but not limited to the lifespan and reliability of the individual heating units 52, the size and cost of the heating units 52, the local heater flux, the characteristics and operation of the heating units 52, and the total power output.

[0031] Each circuit, or selected heating region, is individually controlled at a desired temperature or power level so that the temperature and / or power distribution adapts to variations in system parameters (e.g., changes in manufacturing variability / tolerances, changes in environmental conditions, changes in inlet temperature, inlet temperature distribution, flow velocity, velocity distribution, fluid composition, fluid heat capacity, etc.). More specifically, the heating unit 52 may not produce the same thermal output when operating at the same power level due to manufacturing variability and changes in the degree of heating degradation over time. The heating unit 52 may be independently controlled to adjust the thermal output according to the desired thermal distribution. The individual manufacturing tolerances of the components of the heating system and the assembly tolerances of the heating system are amplified as a function of the modulated power of the power supply; in other words, the manufacturing tolerances of the individual components do not need to be very tight / narrow due to the high fidelity of the heating control.

[0032] Each heating unit 52 may include a temperature sensor (not shown) for measuring the temperature of the heating unit 52. If a hot spot is detected in a heating unit 52, the power supply 14 may reduce or turn off power to the heating unit 52 in which the hot spot was detected in order to prevent overheating or failure of that heating unit 52. The power supply 14 may modulate power to heating units 52 adjacent to the disabled heating unit 52 in order to compensate for the reduced heat output from the heating unit 52.

[0033] The power supply unit 14 may include a multi-region algorithm for turning off or reducing the power level supplied to any specific region and increasing power to heating regions adjacent to a specific heating region that has been disabled and whose thermal output has been reduced. By carefully modulating the power to each heating region, the overall reliability of the system can be improved. The safety of the heating system 10 is improved by detecting hot spots and controlling the power supply accordingly.

[0034] A heating bundle 12 having multiple independently controlled heating regions 62 can achieve improved heating. For example, some circuits on the heating unit 52 can operate at a nominal (or "typical") duty cycle of less than 100% (or at an average power level, which is part of the power generated by the heater to which the line voltage is applied). Lower duty cycles allow the use of resistive heating wiring with a larger diameter, thereby improving reliability.

[0035] Typically, smaller regions use finer wire sizes to achieve a given resistance. Variable power control allows for the use of larger wire sizes, accommodating lower resistance values, while simultaneously protecting the heater from overload through duty cycle limitations tied to the heater's power dissipation capability.

[0036] The use of a scaling factor may relate to the capacity of the heating unit 52 or heating region 62. Multiple heating regions 62 allow for more precise determination and control of the heating bundle 12. By using a specific scaling factor for a particular heating circuit / region, more aggressive (i.e., higher) temperatures (or power levels) are possible in virtually all regions, resulting in a smaller and lower-cost design for the heating bundle 12. Such scaling factors and methods are disclosed in U.S. Patent No. 7,257,464, which is assigned in common with this application and is incorporated herein by reference in its entirety.

[0037] The sizes of the heating regions controlled by individual circuits may be equal or different in order to reduce the total number of regions required to control the temperature or power distribution with the desired precision.

[0038] Referring back to Figure 1, the heating assembly 18 is shown to be a single-end heater, i.e., the conductive pins extend through only one longitudinal end of the heating assembly 18. The heating assembly 18 may extend through a mounting flange 16 or a bulkhead (not shown) and be sealed to the flange 16 or bulkhead. Thus, the heating assembly 18 can be removed and replaced individually without removing the mounting flange 16 from the container or tube.

[0039] Alternatively, the heating assembly 18 may be a "double-ended" heater. In a double-ended heater, the metal sheath is bent into a hairpin shape, and the power conductors pass through both longitudinal ends of the metal sheath, thereby sealing both longitudinal ends of the metal sheath through flanges or bulkheads. In this configuration, the flanges or bulkheads must be removed from the housing or container before the individual heating assemblies 18 can be replaced.

[0040] Referring to Figure 6, the heating bundle 12 is incorporated into the heat exchanger 70. The heat exchanger 70 includes a sealed housing 72 defining an internal chamber (not shown) and the heating bundle 12 positioned within the internal chamber of the housing 72. The sealed housing 72 includes a fluid inlet 76 and a fluid outlet 78 through which the fluid is guided in and out of the internal chamber of the sealed housing 72. The fluid is heated by the heating bundle 12 positioned within the sealed housing 72. The heating bundle 12 may be positioned for either cross-flow or flow parallel to their lengths.

[0041] The heating bundle 12 is connected to a power supply unit 14 which may include power modulation means such as switching means or a variable transformer to modulate the power supplied to individual regions. Power modulation may be performed as a function of time or based on the detected temperature of each heating region.

[0042] The resistive heating wiring can also function as a sensor that measures the temperature of the resistive wiring using the resistance of the wiring and transmits the temperature measurement information to the power supply unit 14 using the same power conductor. The means for sensing the temperature of each region allows for temperature control along the length of each heating assembly 18 in the heating bundle 12 (to the resolution of the individual regions). Thus, additional temperature sensing circuits and sensing means can be omitted, thereby reducing manufacturing costs. Direct measurement of the heating circuit temperature is a clear advantage when seeking to maximize the heat flux in a given circuit while maintaining a desired level of reliability of the system, as it eliminates or minimizes many of the measurement errors associated with the use of separate sensors. The heating element temperature is the characteristic that has the strongest impact on heating reliability. The use of resistive elements to function as both heaters and sensors is disclosed in U.S. Patent No. 7,196,295, which is assigned in common with this application and whose entire contents are incorporated herein by reference.

[0043] Alternatively, the power conductor 56 may be made of dissimilar metals so that the power conductor 56 of dissimilar metals can form a thermocouple for measuring the temperature of the resistive heating element. For example, at least one set of power and power return conductors may include different materials so that a junction is formed between the different materials and the resistive heating element of the heating unit, which is used to determine the temperature of one or more areas. Using “integrated” and “highly thermally coupled” sensing, such as using different metals in the heater, generates a thermocouple-like signal. The use of integrated and coupled power conductors for temperature measurement is disclosed in U.S. Patent Application No. 14 / 725,537, which is assigned in common with this application and whose entire contents are incorporated herein by reference.

[0044] The controller 15 for modulating the power supplied to each region may be a closed-loop automatic control system. The closed-loop automatic control system receives temperature feedback from each region and automatically and dynamically controls the power supply to each region, thereby automatically and dynamically controlling the power distribution and temperature along the length of each heating assembly 18 in the heating bundle 12 without continuous or frequent human monitoring and adjustment.

[0045] The heating units 52 disclosed herein may also be calibrated using a variety of methods, including, but not limited to, energizing and sampling each heating unit 52 to calculate its resistance. The calculated resistance can then be compared to the calibrated resistance to determine the resistance ratio, or a value that determines the actual heating unit temperature. Exemplary methods are disclosed in U.S. Patents 5,280,422 and 5,552,998, which are assigned in common with this application and incorporated herein by reference in their entirety.

[0046] One form of calibration includes operating the heating system 10 in at least one operating mode, controlling the heating system 10 to produce a desired temperature for at least one of the independently controlled heating regions 62, collecting and recording data for at least one independently controlled heating region 62 for the operating mode, then accessing the recorded data to determine the operating specifications of the heating system with a reduced number of independently controlled heating regions, and then using the heating system with a reduced number of independently controlled heating regions. The data may include, for example, power level and / or temperature information, among other operating data from the heating system 10 having collected and recorded data.

[0047] In a modified version of the present disclosure, the heating system may include a single heating assembly 18 instead of multiple heating assemblies within a heating bundle 12. The single heating assembly 18 comprises multiple heating units 52, each heating unit 52 defining at least one independently controlled heating region. Similarly, a power conductor 56 is electrically connected to each of the independently controlled heating regions 62 within each heating unit 52, and the power supply is configured to modulate power to each of the independently controlled heating regions 62 of the heating units via the power conductor 56.

[0048] Referring to Figure 7, the method 100 for controlling a heating system includes, in step 102, providing a heating bundle comprising a plurality of heating assemblies. Each heating assembly comprises a plurality of heating units. Each heating unit defines at least one independently controlled heating circuit (and thus a heating region). In step 104, power to each heating unit is supplied via power conductors electrically connected to each of the independently controlled heating regions within each heating unit. The temperature within each region is detected in step 106. The temperature may be determined using a change in the resistance of a resistive heating element in at least one heating unit. The region temperature can first be determined by measuring the region resistance (or, if appropriate materials are used, by measuring the circuit voltage).

[0049] The temperature values ​​may be digitized. The signal may be communicated to a microprocessor. The measured (detected) temperature values ​​can be compared to the target (desired) temperature of each region in step 108. In step 110, the power supplied to each heating unit can be modulated based on the measured temperature to achieve the target temperature.

[0050] Optionally, the method may further include adjusting the modulated power using a scaling factor. The scaling factor may be a function of the heating capacity of each heating region. The controller 15 may include an algorithm that potentially includes a scaling factor and / or mathematical model of the system's dynamic behavior (including knowledge of the system's update time) to determine the amount of power to be supplied to each region (via duty cycle, phase angle emission, voltage modulation, or similar techniques) until the next update. The desired power may be converted into a signal sent to a switch or other power modulator to control the power output to individual heating regions.

[0051] In this embodiment, if at least one heating region is turned off due to an abnormal condition, the remaining regions continue to provide the desired wattage without failure. Power is modulated to the functional heating regions to provide the desired wattage when an abnormal condition is detected within at least one heating region. If at least one heating region is turned off based on a determined temperature, the remaining regions continue to provide the desired wattage. Power is modulated to each heating region as a function of at least one of the following: received signal, model, and time.

[0052] For safety or process control reasons, typical heaters are generally operated to keep a certain point in the heater below a given temperature to prevent undesirable chemical or physical reactions at that location, such as combustion / ignition / oxidation or coke boiling. Therefore, this is usually addressed by a conservative heating design (e.g., a large heater with low power density and a much lower heat flux than is possible for the majority of its surface area).

[0053] However, using the heating bundle of this disclosure, it is possible to measure and limit the temperature at any location within the heater to a resolution of the size of the individual heating regions. Hot spots large enough to affect the temperature of individual circuits can be detected.

[0054] The ability to automatically adjust and consequently limit the temperature of individual heating regions ensures that the dynamic and automatic temperature limiting of each region keeps this region and all others operating at optimal power / heat flux levels without risking exceeding the desired temperature limit of any given region. This offers advantages in higher limit temperature measurement accuracy than current implementations that clamp separate thermocouples to the sheath of one of the elements in the bundle. The reduced margin and the ability to modulate power to individual regions can be applied selectively and individually to heating regions rather than to the entire heating assembly, thereby reducing the risk of exceeding a given temperature limit.

[0055] The characteristics of a cartridge heater can change over time. This time-varying characteristic would otherwise necessitate the cartridge heater being designed for a single, selected (worst-case) flow mode, and therefore operating in a suboptimal state for other flow conditions.

[0056] However, dynamic control of the power distribution across the entire bundle to the resolution of the core size by multiple heating units provided in the heating assembly makes it possible to achieve optimized power distributions for various flow conditions, in contrast to the single power distribution corresponding to only one flow condition in a typical cartridge heater. Thus, the heating bundle of this application enables an increase in total heat flux for all other flow conditions.

[0057] Furthermore, variable power control can increase the flexibility of heating design. Voltage can be isolated (to a considerable extent) from resistance in the heating design, and the heater can be designed with the largest wire diameter that can be mated to the heater. This allows for an increase in the capacity of power dissipation for a given heating size and reliability level (or heater lifespan), and a decrease in the size of the bundle for a given overall power level. The power in this configuration can be modulated by a variable duty cycle, which is part of a variable wattage controller currently available or under development. The heating bundle can be protected by programmable (or pre-programmed as needed) limits on the duty cycle in a given area to prevent "overloading" of the heating bundle.

[0058] Referring to Figure 8, a perspective view of a heating assembly 50 equipped with a heat supply unit is shown. Generally, the heat supply unit is configured to modify the thermal conductance along the length of at least one heating assembly to compensate for non-uniform temperature. Non-uniform temperature may occur within at least one heating unit, such as an end heating unit as described below as an example. Alternatively, non-uniform temperature may occur between adjacent heating units of the heating assembly. This heat supply unit can take various forms, as will be described in more detail below, and can be implemented in one or more heating units.

[0059] Thus, each heating assembly 50 comprises a plurality of heating units 52. Each heating unit 52 defines either an end heating unit 52-1 or an adjacent heating unit 52-2. As shown in Figures 9 to 10, each of the end heating unit 52-1 and the adjacent heating unit 52-2 includes a core body 58 and a resistance heating element 60 surrounding the core body 58. The resistance heating element 60 of each end heating unit 52-1 defines one or more end heating regions 62-1, and the resistance heating element 60 of each adjacent heating unit 52-2 defines one or more adjacent heating regions 62-2. The resistance heating elements 60 of the end heating units 52-1 and the adjacent heating units 52-2 are connected to a power conductor 56, which is connected to a power supply unit 14. The power conductor 56 supplies power from the power supply unit 14 to the end heating units 52-1 and the adjacent heating units 52-2. By selectively connecting the power conductor 56 to the resistance heating element 60, the resistance heating elements 60 of the end heating unit 52-1 and the adjacent heating unit 52-2 can be independently controlled by the controller 15 of the power supply unit 14.

[0060] In one embodiment, the heat supply section of the heating assembly 50 is implemented by a conductive sleeve 120. As an example, referring to Figure 10, the conductive sleeve 120 is positioned close to the resistance heating element 60 of the end heating unit 52-1. In one embodiment, the conductive sleeve 120 surrounds the resistance heating element 60 and the core body 58, and is positioned between the outer metal sheath 54 and the resistance heating element 60. It should be understood that in other embodiments, the conductive sleeve 120 does not have to completely surround the resistance heating element 60 and the core body 58. It should also be understood that in other embodiments, the conductive sleeve 120 does not have to be positioned between the outer metal sheath 54 and the resistance heating element 60.

[0061] In one embodiment, the conductive sleeve 120 has a greater thermal conductivity than the outer metal sheath 54. Thus, the conductive sleeve 120 is configured to increase the conductance of the end heating unit 52-1 relative to the adjacent heating unit 52-2, thereby suppressing an undesirable temperature gradient along the heating assembly 50.

[0062] Referring to Figure 11, a perspective view of a heating assembly 50 having another exemplary heat supply unit is shown. In one embodiment, the heat supply unit of the heating assembly 50 is implemented by an outer sheath heat supply unit 130. Referring to Figures 12-13 in more detail, the heating assembly 50 includes an end outer metal sheath 54-1 and an adjacent outer metal sheath 54-2, respectively. The end outer metal sheath 54-1 and the adjacent outer metal sheath 54-2 collectively form the outer metal sheath 54, and the outer sheath heat supply unit 130 is implemented in one embodiment by the end outer metal sheath 54-2. However, it should be understood that the outer sheath heat supply unit 130 may be implemented in any of the heating units and is therefore not limited to the end heating unit 52-1.

[0063] In one embodiment, the end outer metal sheath 54-1 and the adjacent outer metal sheath 54-2 have different thicknesses and / or thermal conductivity. As an example, the end outer metal sheath 54-1 has a greater thickness and higher thermal conductivity than the adjacent outer metal sheath 54-2. Thus, the end outer metal sheath 54-1 is configured to increase the conductance of the end heating unit 52-1 relative to the adjacent heating unit 52-2, thereby suppressing an undesirable temperature gradient along the heating assembly 50. It should be understood that the end outer metal sheath 54-1 and the adjacent outer metal sheath 54-2 can have different thicknesses and / or thermal conductivity in other variants to selectively control the temperature gradient along the heating assembly 50.

[0064] Referring to Figure 14, a perspective view of a heating assembly 50 having another exemplary heat supply is shown. In this embodiment, the heat supply of the heating assembly 50 is implemented by a power conductor heat supply unit 140. The power conductor heat supply unit 140 is implemented by a power conductor 56-1 (which may be at the end as shown in one embodiment, or at any other location along the heating assembly 50) and an adjacent power conductor 56-2. In one embodiment, the power conductor 56-1 and the adjacent power conductor 56-2 collectively form a plurality of power conductors 56. The power conductor 56-1 is connected to the resistance heating element 60 of the end heating unit 52-1, and the adjacent power conductor 56-2 is connected to the resistance heating element 60 of the adjacent heating unit 52-2.

[0065] In some configurations, referring to Figures 14-15, the power conductor 56-1 and the adjacent power conductor 56-2 have different thicknesses, cross-sectional areas, and / or thermal conductivity. As an example, power conductor 56-1 has a greater thickness (T1) and cross-sectional area (proportional to the thickness T1 in this configuration) than the thickness (T2) and cross-sectional area (proportional to the thickness T2 in this configuration) of the adjacent power conductor 56-2. Thus, power conductor 56-1 is configured to increase the conductance of the end heating unit 52-1 relative to the adjacent heating unit 52-2, thereby suppressing an undesirable temperature gradient along the heating assembly 50. It should be understood that the end power conductor 56-1 and the adjacent power conductor 56-2 can have different thicknesses, cross-sectional areas, and / or thermal conductivity in other configurations in order to selectively control the temperature gradient along the heating assembly 50.

[0066] Referring to Figure 16, a perspective view of a heating assembly 50 having another exemplary heat supply section is shown. In one embodiment, the heating assembly 50 includes a spacing 150 and an adjacent spacing 152, and the heat supply section of the heating assembly 50 is defined by the spacing 150 (which may be at the end as shown in one embodiment, or at any other position along the heating assembly 50). As used herein, “spacing” refers to the gap between consecutive heating units 52. As an example, spacing 150 refers to the gap between an end heating unit 52-1 and an adjacent heating unit 52-2, and adjacent spacing 152 refers to the gap between adjacent heating units 52-2. In one embodiment, the width in the longitudinal direction X of the end spacing 150 (W1) is greater than the width in the longitudinal direction X of the adjacent spacing 152 (W2).

[0067] Please note that while the widths of the spacing 150(W1) shown in Figure 16 are equal, in other embodiments the widths of the spacing 150(W1) do not have to be equal. Similarly, while the widths of the adjacent spacings 152(W2) shown in Figure 15 are equal, in other embodiments the widths of the adjacent spacings 152(W2) do not have to be equal. In one embodiment, the width of the end spacing 150(W1) is less than or equal to the width of the adjacent spacing 152(W2). By selectively specifying the widths of the spacing 150(W1) and the adjacent spacing 152(W2), the conductance of the end heating unit 52-1 (or any other heating unit along the length of the heating assembly 50) relative to the adjacent heating unit 52-2 can be increased to suppress undesirable temperature gradients along the length of the heating assembly 50.

[0068] Referring to Figure 17, a perspective view of a heating assembly 50 having another exemplary heat supply unit is shown. In some embodiments, the heating assembly 50 includes a spacer 160 (which may be at the end, as shown in one embodiment, or at any other position along the heating assembly 50) and an adjacent spacer 162, and the heat supply unit of the heating assembly 50 is carried out by the spacer 160. The spacer 160 is positioned between the end heating unit 52-1 and the adjacent heating unit 52-2, and the adjacent spacer 162 is positioned between the adjacent heating units 52-2. The spacer 160 and the adjacent spacer 162 can be carried out by a variety of materials having lower thermal conductivity, such as ceramic materials (e.g., aluminum nitride, boron nitride, polyurethane, and glass-based materials such as borosilicate glass, acrylic glass, and glass fiber, among others).

[0069] In some configurations, the longitudinal width X of spacer 160 (W3) is greater than the longitudinal width X of the adjacent spacer 162 (W4). While the widths of spacer 160 (W3) are equal in Figure 17, it should be understood that the widths of spacer 160 (W3) may not be equal in other configurations. Similarly, while the widths of adjacent spacer 162 (W4) are equal in Figure 15, it should be understood that the widths of adjacent spacer 162 (W4) may not be equal in other configurations. In one configuration, the width of spacer 160 (W3) is less than or equal to the width of the adjacent spacer 162 (W4). By selectively specifying the width of spacer 160 (W3) and the width of the adjacent spacer 162 (W4), the conductance of any other heating unit along the length of the end heating unit 52-1 or heating assembly 50 relative to the adjacent heating unit 52-2 can be increased, thereby suppressing undesirable temperature gradients along the heating assembly 50.

[0070] In one embodiment, the power conductor heat supply section 140 and spacer 160 described above are combined to form a heat supply section, as shown in Figures 14-15. As an example, as shown in Figures 18-19, the power conductor 56-1 extends longitudinally X along the heating assembly 50 so that the power conductor 56-1 is located within the corresponding spacer 160 and within the corresponding end heating unit 52-1 (not shown). Similarly, the adjacent power conductor 56-2 extends longitudinally X along the heating assembly 50 so that the adjacent power conductor 56-2 is located within the corresponding adjacent spacer 162 and within the corresponding adjacent heating unit 52-2 (not shown). In some embodiments, the power conductor 56-1 located within spacer 160 has a larger cross-sectional area than the adjacent power conductor 56-2 located within the adjacent spacer 162. It should be understood that the power conductor 56-1 located within spacer 160 may have a cross-sectional area less than or equal to that of the adjacent power conductor 56-2 located within the adjacent spacer 162 in other embodiments.

[0071] Referring to Figure 20, a perspective view of a heating assembly 50 having another exemplary heat supply is shown. In one embodiment, the heat supply of the heating assembly 50 is implemented by a variable-width heat supply unit 170. The variable-width heat supply unit 170 includes at least one of end heating units 52-1 (or any other heating units along the length of the heating assembly 50). In some embodiments, the width in the longitudinal direction X of the end heating unit 52-1 (W5) is greater than the width in the longitudinal direction X of the adjacent heating unit 52-2 (W6). It should be noted that in other embodiments, the width of the end heating unit 52-1 (W5) may be less than or equal to the width of the adjacent heating unit 52-2 (W6). By selectively specifying the width (W5) of the end heating unit 52-1 and the width (W6) of the adjacent heating unit 52-2, the conductance of the end heating unit 52-1 relative to the adjacent heating unit 52-2 can be increased to suppress undesirable temperature gradients along the heating assembly 50. Although not shown in the diagram, it should be easily understood that the power conductor for heating unit 52 extends between the end heating unit 52-1 and the adjacent heating unit 52-2.

[0072] Referring to Figures 8 to 20, the controller 15 is configured to calculate the temperature in the end heating unit 52-1 based on a predetermined model (e.g., a mathematical model representing, among other things, the various components and / or dynamic behavior of the heating system 10) and at least one input. In one embodiment, at least one input includes, but is not limited to, the temperature at another location in the heating bundle 12, the average temperature of the heating unit 52, the average temperature of any of the independently controlled heating regions 62 located on the heating assembly 18, the power consumption of either the heating bundle 12 and / or the heating unit 52, and / or the average power consumption of either the heating bundle 12 and / or the heating unit 52 over a predetermined period of time. In one embodiment, at least one input includes, but is not limited to, the voltage of either the heating bundle 12 and / or the heating unit 52, the current of either the heating bundle 12 and / or the heating unit 52, the current leakage of either the heating bundle 12 and / or the heating unit 52, and / or the insulation resistance of the heating bundle 12. To perform the functions described herein, the controller 15 includes one or more electrical circuits / components for acquiring at least one input (e.g., one or more sensing circuits for measuring the power of the heating unit 52).

[0073] As an example, the controller 15 is configured to calculate the temperature within the end heating unit 52-1 by first supplying a known current to the end heating unit 52-1 and measuring the voltage across the end heating unit 52-1. The controller 15 then compares the measured voltage to a nominal voltage associated with the known current to identify a voltage deviation and / or a corresponding resistance deviation. Subsequently, the controller 15 calculates the temperature of the end heating unit 52-1 based on the voltage deviation and / or the corresponding resistance deviation using a predetermined model. As described above, the controller 15 then modulates power to the independently controlled heating region 62 via the power conductor 56 based on the temperature of the end heating unit 52-1. To perform the functions described herein, the controller 15 includes one or more processors configured to execute instructions stored in a non-temporary computer-readable medium such as random access memory (RAM) and / or read-only memory (ROM).

[0074] Unless otherwise expressly indicated herein, all numerical values ​​indicating mechanical / thermal properties, compositional percentages, dimensions and / or tolerances, or other properties should be understood to be modified by the word “about” or “approximately” when describing the scope of this disclosure. This modification is desirable for a variety of reasons, including industrial implementation, material, manufacturing, and assembly tolerances, as well as test capability.

[0075] The spatial and functional relationships between elements are described using a variety of terms, including “connected,” “engaged,” “joined,” “adjacent,” “next to,” “above,” “above,” “below,” and “positioned.” Unless expressly stated to be “direct,” where a relationship between a first element and a second element is described in this disclosure, that relationship may be a direct relationship in which there are no other intervening elements between the first element and the second element, or an indirect relationship in which there are one or more intervening elements (spatially or functionally) between the first element and the second element. Where used herein, the phrase “at least one of A, B, and C” should be interpreted as meaning (A OR B OR C) using the non-exclusive logic OR, and not as “at least one of A, at least one of B, and at least one of C.”

[0076] The descriptions in this disclosure are essentially illustrative, and therefore, any modifications that do not deviate from the content of this disclosure are intended to be within the scope of this disclosure. Such modifications should not be considered a departure from the spirit and scope of this disclosure. Furthermore, various omissions, substitutions, combinations, and modifications of the forms of systems, apparatus, and methods described herein can be made without departing from the spirit and scope of this disclosure, even if such omissions, substitutions, combinations, and modifications are not expressly shown or illustrated in the figures of this disclosure.

Claims

1. 1. A heating system comprising: A heating bundle comprising: a plurality of heating assemblies, at least one of the heating assemblies comprising a plurality of heating units, at least one heating unit being an independently controlled heating zone; at least one thermal provision provided in a portion of the at least one heating assembly for modifying the thermal conductance of the portion of the at least one heating assembly relative to an adjacent portion of the at least one heating assembly; a heating bundle including: a plurality of power conductors electrically connected to the plurality of heating units; a means for determining a temperature; a power supply including a controller configured to modulate power to the independently controlled heating zones via the power conductors based on the determined temperature to provide a desired power output along a length of the at least one heating assembly; A heating system comprising:

2. The heating system of claim 1 , wherein the at least one heating unit is an end heating unit disposed at an end of the at least one heating assembly.

3. The heating system of claim 1 , wherein the thermal provision increases the thermal conductance within the at least one heating unit.

4. 4. The heating system of claim 3, wherein the at least one thermal-related feature comprises a conductive sleeve proximate to a resistive heating element of the at least one heating unit, the conductive sleeve having a thermal conductivity greater than a thermal conductivity of an outer metal sheath at least partially surrounding the resistive heating element.

5. 4. The heating system of claim 3, wherein each of the heating units comprises an outer sheath, and the at least one heat-related arrangement comprises the at least one heating unit having an outer sheath with a thickness greater than an adjacent heating unit outer sheath.

6. 4. The heating system of claim 3, wherein each of the heating units comprises an outer sheath, and the at least one heat-related arrangement comprises the at least one heating unit having an outer sheath with a higher thermal conductivity than an adjacent heating unit outer sheath.

7. 4. The heating system of claim 3, wherein the at least one heat-related provision comprises at least two power conductors operably connected to the at least one heating unit, and at least one of the two power conductors has a greater thickness adjacent the at least one heating unit.

8. 4. The heating system of claim 3, wherein the at least one heat-related provision comprises at least two power conductors operably connected to the at least one heating unit, and at least one of the two power conductors has a higher thermal conductivity in proximity to the at least one heating unit.

9. The heating system of claim 3 , wherein the at least one heat-related provision comprises a length of the at least one heating unit that is shorter than a length of an adjacent heating unit.

10. 10. The heating system of claim 1, wherein the at least one heating assembly defines spacings between adjacent heating units, and the at least one heat-related provision includes that at least one of the spacings varies between heating units.

11. The heating system of claim 1 , wherein spacers are disposed between adjacent heating units, and the at least one heat-related provision comprises a spacer between the at least one heating unit and an adjacent heating unit that is thicker than other spacers.

12. 2. The heating system of claim 1, wherein the at least one heat-related feature includes a plurality of power supply conductors, and at least one first power supply conductor of the plurality of power supply conductors connected to an end heating unit has a smaller cross-sectional area than at least one second power supply conductor of the plurality of power supply conductors connected to a heating unit adjacent to the end heating unit.

13. The heating system of claim 1 , wherein the at least one heating assembly includes resistive heating elements, and at least one of the resistive heating elements functions as a sensor.

14. The heating system of claim 1 , wherein two or more of the heating units define at least one independently controlled heating zone.

15. 1. A heating system comprising: A heating bundle comprising: a plurality of heating assemblies, at least one of the heating assemblies comprising a plurality of heating units, at least one heating unit being an independently controlled heating zone; at least one thermal provision provided in a portion of the at least one heating assembly for modifying the thermal conductance of the portion of the at least one heating assembly relative to an adjacent portion of the at least one heating assembly; a heating bundle including: a plurality of power conductors electrically connected to the plurality of heating units; means for determining at least one of heating conditions and heating requirements; a power supply including a controller configured to modulate power to the independently controlled heating zones via the power conductors based on the at least one of heating conditions and heating requirements to provide a desired power output along a length of the at least one heating assembly; A heating system comprising:

16. The heating system of claim 15 , wherein the at least one heating unit is an end heating unit disposed at an end of the at least one heating assembly.

17. The heating system of claim 15 , wherein the thermal provision increases the thermal conductance within the at least one heating unit.

18. 16. The heating assembly of claim 15, wherein the at least one of heating conditions and heating requirements is selected from the group consisting of: life of the heating unit, reliability of the heating unit, size of the heating unit, cost of the heating unit, local heater flux, characteristics and operation of the heating unit, and total power.

19. The heating system of claim 15 , wherein two or more of the heating units define at least one independently controlled heating zone.

20. 1. A heating system comprising: a heating assembly comprising a plurality of heating units, at least one of the heating units being an independently controlled heating zone; at least one thermally related provision provided in a portion of the heating assembly for modifying the thermal conductance of the portion of the heating assembly relative to an adjacent portion of the heating assembly; a plurality of power conductors electrically connected to the plurality of heating units; a power supply including a controller configured to modulate power to the independently controlled heating zones via the power conductors based on at least one of heating conditions and heating requirements to provide a desired power output along the length of the heating assembly; A heating system comprising:

21. 21. The heating system of claim 20, wherein the at least one heating unit is an end heating unit located at an end of the heating assembly.

22. 21. The heating system of claim 20, further comprising a means for determining a temperature.

23. 21. The heating system of claim 20, further comprising means for determining heating conditions or requirements.

24. 21. The heating system of claim 20, wherein two or more of the heating units define at least one independently controlled heating zone.

25. 1. An apparatus for heating a fluid, comprising: a sealed housing defining an interior chamber and having a fluid inlet and a fluid outlet; 21. The heating system of claim 20, wherein the heating assembly is disposed within the interior chamber of the housing; Equipped with The apparatus, wherein the heating assembly is adapted to provide a responsive heat distribution to a fluid within the housing.

26. 21. The heating system of claim 20, wherein the heating assembly includes resistive heating elements, at least one of the resistive heating elements functioning as a sensor.

27. ​​The heating system described in claim 3, wherein the at least one heat-related feature comprises a conductive sleeve at least partially surrounding the at least one heating unit, the conductive sleeve being separated from an outer metal sheath surrounding the multiple heating units.

28. A heating system as described in Claim 27, wherein the conductive sleeve is positioned between the outer metal sheath and the at least one heating unit.

29. The heating system of claim 3, wherein the at least one thermal-related provision is configured to vary thermal conductance along the length of the at least one heating assembly to compensate for uneven temperatures within the at least one end heating unit or between adjacent heating units of the at least one heating assembly.

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