Heating bundle with variable power output within the region

Abstract

To provide a heater system including a heater bundle.SOLUTION: A heater system includes a heater bundle with heater assemblies, at least one of the heater assemblies having a plurality of heater units, at least one heater unit having an independently controlled heating zone, and the at least one heater assembly having a physical construction configured to deliver a variable power output per unit length along a length of the at least one heater assembly. A plurality of power conductors are electrically connected to the plurality of heater units and the heater system further includes a means for determining temperature. A power supply device includes 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 the 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, entitled "Heater Bundle for Adaptive Control", which is a continuation application of U.S. Patent Application No. 15 / 058,838 filed on March 2, 2016, 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 fluid streams such as heat exchangers.

BACKGROUND ART

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

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

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] [Means for solving the problem]

[0006] 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 heating unit having an independently controlled heating region, and at least one heating assembly comprising a physical structure configured to deliver a variable power output per unit length along the length of at least one heating assembly. A plurality of power conductors are electrically connected to the plurality of heating units, and the heating system further comprises means for determining the temperature. The power supply includes a controller configured to modulate power to the independently controlled heating region via the power conductor based on the determined temperature in order to provide a desired power output along the length of at least one heating assembly.

[0007] Modifications of this heating system, which can be implemented individually or in any combination, include: a physical structure comprising a resistive heating element in at least one heating unit having a variable pitch, wherein the variable pitch is continuously variable along the length of the resistive heating element; a physical structure comprising a resistive heating element in at least one heating unit having a variable cross-sectional area; a physical structure comprising a resistive heating element in at least one heating unit having a variable cross-sectional area and a variable pitch; a physical structure comprising a plurality of parallel circuits in at least one heating unit; a physical structure provided in two or more of a plurality of heating units, wherein the physical structure is positioned closer to the end of an adjacent heating unit or at least one heating assembly to have a higher electrical resistivity and another pair The physical structure includes a composite heating element having a lower electrical resistivity closer to an adjacent heating unit facing it, the physical structure is provided in two or more of the heating assemblies, at least one of the heating assemblies is a cartridge heater, the physical structure comprises at least one heating unit having a different cross-sectional area from the adjacent heating unit, the heating unit comprises a plurality of resistive heating elements, at least one of the resistive heating elements functions as a sensor, and the physical structure includes a composite heating element having a variable electrical resistivity, the variable electrical resistivity includes a higher electrical resistivity closer to the end of an adjacent heating unit or at least one heating assembly, and a lower electrical resistivity closer to an adjacent heating unit facing it.

[0008] In another embodiment, the device for heating a fluid comprises the aforementioned heating system along with a sealed housing that defines an internal chamber and has a fluid inlet and a fluid outlet, wherein the heating bundle is positioned within the internal chamber of the housing. The heating bundle is adapted to provide a responsive heat distribution to the fluid within the housing.

[0009] In yet another embodiment, the heating system includes a heating bundle comprising a plurality of heating assemblies, at least one of which comprises a plurality of heating units, at least one heating unit having an independently controlled heating region, and at least one heating assembly comprising a physical structure configured to deliver a variable power output per unit length along the length of at least one heating assembly. A plurality of power conductors are electrically connected to the heating units and means are provided for determining at least one of heating conditions and heating requirements. The power supply includes a controller configured to modulate power to the independently controlled heating region via the power conductors based on at least one of the heating conditions and heating requirements to provide a desired power output along the length of at least one heating assembly.

[0010] In this modified heating system, 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, heater flux, heating unit characteristics and operation, power output, power input, and total heat generated.

[0011] In further modifications, the apparatus includes a sealed housing that defines an internal chamber and has a fluid inlet and a fluid outlet. A heating assembly is located within the internal chamber of the housing and is adapted to provide a heat distribution in response to the fluid within the housing.

[0012] In yet another embodiment of the present disclosure, the heating system comprises a heating assembly having a plurality of heating units, at least one of which has an independently controlled heating region, and the heating assembly comprises a physical structure configured to deliver a variable power output per unit length along the length of the heating assembly. A plurality of power conductors are electrically connected to the heating units, and the power supply unit includes a controller configured to modulate power to the independently controlled heating region 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.

[0013] Modifications of this heating system, which can be implemented individually or in any combination, provide means for determining the temperature and means for determining the heating conditions or heating requirements.

[0014] In another form of this heating system, the device for heating a fluid 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 within the housing.

[0015] 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.

[0016] 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]

[0017] [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]FIG. 1 is a perspective view of a variant of the heating assembly of the heating bundle in accordance with the teachings of the present disclosure. [Figure 4] FIG. 3 is a perspective view of the heating assembly of FIG. 3 in accordance with the teachings of the present disclosure, with the outer sheath of the heating assembly removed for clarity. [Figure 5] FIG. 4 is a perspective view of the core body of the heating assembly of FIG. 3 in accordance with the teachings of the present disclosure. [Figure 6] FIG. 1 is a perspective view of a heat exchanger including the heating bundle of FIG. 1 in accordance with the teachings of the present disclosure, the heating bundle being partially disassembled from the heat exchanger to expose the heating bundle for illustrative purposes. [Figure 7] FIG. 2 is a block diagram of a method of operating a heating system including a heating bundle constructed in accordance with the teachings of the present disclosure. [Figure 8A] FIG. 1 is a side view of one embodiment of a heating unit having variable power output constructed in accordance with the teachings of the present disclosure. [Figure 8B] FIG. 3 is a side view of another embodiment of a heating unit having variable power output constructed in accordance with the teachings of the present disclosure. [Figure 8C] FIG. 4 is a side view of yet another embodiment of a heating unit having variable power output constructed in accordance with the teachings of the present disclosure. [Figure 8D] FIG. 5 is a side view of still another embodiment of a heating unit having variable power output constructed in accordance with the teachings of the present disclosure. [Figure 8E] FIG. 6 is a schematic side view of another embodiment of a heating unit having a plurality of parallel circuits for providing variable power output in accordance with the teachings of the present disclosure. [Figure 9] FIG. 7 is a perspective view of a heating unit having different cross-sectional areas and constructed in accordance with the teachings of the present disclosure. [Detailed Description of the Embodiments]

[0018] The drawings described in the present specification are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way.

[0019] The following descriptions are essentially illustrative and are not intended to limit the scope of this disclosure, use, or application.

[0020] Referring to Figure 1, a heating system configured in accordance with the teachings of this disclosure is shown collectively by reference numeral 10. The heating system 10 includes a heating bundle 12 and a power supply 14 electrically connected to the heating bundle 12. The power supply 14 includes a controller 15 for controlling the power supply to the heating bundle 12. As used in this disclosure, “heating bundle” refers to a heating system that includes two or more physically separate heating devices that can be controlled independently. Thus, if one of the heating devices in the heating bundle fails or deteriorates, the remaining heating devices in the heating bundle 12 can continue to operate.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] For example, a heating assembly 50 can define m heating regions, and a heating bundle may include 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 flux of the heaters, the characteristics and operation of the heating units 52, the power output, the power input, and the total heat generated.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] Alternatively, the heating assembly 18 may be a "double-ended" heater. In double-ended heating, 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 partitions. In this configuration, the flanges or partitions must be removed from the housing or container before the individual heating assemblies 18 can be replaced.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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 No. 10,728,956, which is assigned in common with this application and whose entire contents are incorporated herein by reference.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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).

[0050] The temperature values ​​may be digitized and communicated to a microprocessor. The measured (detected) temperature values ​​can be compared to the target (desired) temperature of each region in step 108. Then, in step 110, the power supplied to each heating unit is modulated based on the measured temperature to achieve the target temperature.

[0051] 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.

[0052] 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.

[0053] For safety or process control reasons, typical heaters are generally operated to keep a certain point of 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 the surface area).

[0054] 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.

[0055] 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.

[0056] The characteristics of a cartridge heater can change over time. This time-varying characteristic would otherwise require the cartridge heater to be designed for a single, selected (worst-case) flow mode, and therefore to operate suboptimally for other flow conditions.

[0057] 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.

[0058] 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 the heating bundle from "overloading".

[0059] Referring here to Figures 8A to 8D, an additional embodiment of the present disclosure is shown in which at least one heating assembly 50 has a physical structure configured to supply a variable power output per unit length along the length of at least one heating assembly 50. This variable power output can be implemented in various ways and in various combinations, some of which are illustrated and described herein as examples. The physical structures described below may be provided in any combination of one or more heating units 52 and one or more heating assemblies 50. Furthermore, the additional teachings herein regarding variable power output can be combined individually or in any combination with any of the aforementioned embodiments of the present disclosure, while remaining within the scope of the present disclosure.

[0060] In one embodiment shown in Figure 8A, the variable power output is provided by the physical structure of the resistive heating element 120 having a variable pitch. As used herein, the term “pitch” refers to the distance between the center points of the continuous windings of the resistive heating element 120 along the longitudinal direction X, as indicated by P1, P2, and P3 in this example. As shown in this example, the heating unit 52 has three distinct regions having different pitches P1, P2, and P3.

[0061] In another embodiment shown in Figure 8B, the pitch is continuously variable along the length of the resistance heating element 120, or along the longitudinal direction X. More specifically, the pitch between each winding changes continuously along the length; in other words, the pitch between adjacent windings is continuously different from one winding to the next. In this example, P1≠P2≠P3≠P4≠P5≠P6≠P7≠P8. However, a pitch such as P4 may be equal to pitch P7, provided that the pitch between adjacent windings is different from the continuously variable pitch from one winding to the next.

[0062] In yet another embodiment shown in Figure 8C, the variable power output is provided by a resistive heating element 120 having a variable cross-sectional area. This variable cross-sectional area may be provided by a resistive heating element 120 having different wire diameters D1, D2, and D3 as shown, or the wire diameter itself may be continuously variable along its length (not shown). In another example not shown, if the resistive heating element 120 is formed by a layering process, its thickness and / or width may vary with respect to the variable power output. This structure is described in detail in U.S. Patent No. 7,132,628, entitled "Variable Watt Density Layered Heating System," which is owned in common with this application and whose entire contents are incorporated herein by reference. It should be understood that these and other modifications providing a variable cross-sectional area to the resistive heating element 120 are to be construed as being within the scope of this disclosure.

[0063] Referring to a further example in Figure 8D, the variable power output may comprise a resistance heating element 120 having both a variable cross-sectional area and a variable pitch. In this example, three different cross-sectional areas are used with diameters D1, D2, and D3, and three different pitches are used with pitches P1, P2, and P3. These examples and other combinations of different cross-sectional areas and pitches for providing a variable power output within each heating unit 52 should be construed as being within the scope of this disclosure.

[0064] Referring here to Figure 8E, at least one of the other embodiments of the heating unit 52 includes a plurality of parallel circuits having resistors R1, R2, R3, R4, and R5 of different values ​​for each resistive heating element 120 to provide a variable power output. In this embodiment, each resistive heating element 120 is electrically connected in parallel across the power conductor 42. In another embodiment, the resistive heating elements 120 can be connected in parallel using a busbar (not shown), in which case the busbar is electrically in communication with the power conductor 42. It should be understood that any number of resistive heating elements 120 and different resistance values ​​can be used, while remaining within the scope of this disclosure other than those shown herein. Regarding different resistance values, this can be achieved in various ways, including, for example, different material compositions and different cross-sectional areas.

[0065] In one embodiment of this disclosure, each heating unit 52 has a different power distribution from adjacent heating units in a given heating assembly 50. In another embodiment, at least one heating unit 52 has independently controlled heating regions with variable power output in two or more heating assemblies 50. These, among other variations of variable power output shown herein, are within the scope of this disclosure and may be used with heating bundles and heating assemblies as shown and described herein.

[0066] In yet another form, variable power output may be achieved by using a composite heating element. The composite heating element is made of a material that includes a material having variable electrical resistivity along its length and is therefore configured to supply variable power output. As an example, the composite heating element of a heating unit has higher electrical resistivity at one end (near an adjacent heating unit or near the end of a heating assembly) and lower electrical resistivity very close to the other end (near another opposing adjacent heating unit).

[0067] Referring to Figure 9, in another modification of the present disclosure, the physical structure comprises at least one heating unit 52 having a different cross-sectional area from adjacent heating units. It should be understood that two or more heating units 52 may have different cross-sectional areas from other heating units, and one or more heating assemblies 50 may have heating units 52 having different cross-sectional areas. Combined with the modulation of power to the independently controlled heating regions as described above, these variable cross-sectional areas (in addition to the other physical structures described herein) is another way to generate a large difference in power output along the length of the heating assembly 50 while separating the physical structure that provides a variable power output from the power value per unit area of ​​the independently controlled regions.

[0068] 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.

[0069] 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.”

[0070] 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 deviation from the spirit and scope of this disclosure. 。 The invention described in the original claims of this application is listed below. [1] A heating system, It is a heated bundle, A plurality of heating assemblies, wherein at least one of the heating assemblies comprises a plurality of heating units, at least one heating unit having a heating region that is independently controlled, and the at least one heating assembly has a physical structure configured to deliver a variable power output per unit length along the length 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 temperature, A power supply unit including a controller configured to modulate power to the independently controlled heating region via the power conductor based on the determined temperature in order to provide a desired power output along the length of the at least one heating assembly, A heating system equipped with the following features. [2] The heating system according to [1], wherein the physical structure includes a resistance heating element in at least one heating unit having a variable pitch. [3] The heating system according to [2], wherein the variable pitch is continuously variable along the length of the resistance heating element. [4] The heating system according to [1], wherein the physical structure includes a resistance heating element in at least one heating unit having a variable cross-sectional area. [5] The heating system according to [1], wherein the physical structure includes a resistance heating element in at least one heating unit having a variable cross-sectional area and a variable pitch. [6] The heating system according to [1], wherein the physical structure includes a plurality of parallel circuits within at least one heating unit. [7] The heating system according to [1], wherein the physical structure is provided in two or more of the plurality of heating units. [8] The heating system according to [1], wherein the physical structure includes a composite heating element having a higher electrical resistivity in proximity to an adjacent heating unit or the end of the at least one heating assembly and a lower electrical resistivity in proximity to another opposing adjacent heating unit. [9] The heating system according to [1], wherein the physical structure is provided in two or more of the heating assemblies.

[10] The heating system according to [1], wherein at least one of the plurality of heating assemblies is a cartridge heater.

[11] The heating system according to [1], wherein the physical structure includes at least one heating unit having a different cross-sectional area from adjacent heating units.

[12] The heating system according to [1], wherein the heating unit includes a plurality of resistive heating elements, and at least one of the resistive heating elements functions as a sensor.

[13] The heating system according to [1], wherein the physical structure comprises a composite heating element having variable electrical resistivity.

[14] The heating system according to

[13] , wherein the variable resistivity includes a higher resistivity in proximity to an adjacent heating unit or the end of the at least one heating assembly, and a lower resistivity in proximity to an opposing adjacent heating unit.

[15] A device for heating a fluid, A sealed housing having an internal chamber, a fluid inlet and a fluid outlet, The heating bundle comprises the heating system described in [1], which is located within the internal chamber of the housing, The apparatus wherein the heating bundle is adapted to provide a responsive heat distribution to the fluid within the housing.

[16] A heating system, It is a heated bundle, A plurality of heating assemblies, wherein at least one of the heating assemblies comprises a plurality of heating units, at least one heating unit having a heating region that is independently controlled, and the at least one heating assembly has a physical structure configured to deliver a variable power output per unit length along the length of the at least one heating assembly, A heating bundle including a plurality of power conductors electrically connected to the heating unit, Means for determining at least one of heating conditions and heating requirements, A power supply unit including a controller configured to modulate power to the independently controlled heating region via the power conductor based on at least one of heating conditions and heating requirements, in order to provide a desired power output along the length of the at least one heating assembly, A heating system equipped with the following features.

[17] The heating assembly according to

[16] , wherein at least one of the heating conditions and heating requirements is selected from the group consisting of the lifespan of the heating unit, the reliability of the heating unit, the size of the heating unit, the cost of the heating unit, the flux of the heater, the characteristics and operation of the heating unit, the power output, the power input, and the total heat generated.

[18] A device for heating a fluid, A sealed housing having an internal chamber, a fluid inlet and a fluid outlet, The heating assembly comprises the heating system described in

[16] , which is located within the internal chamber of the housing, The apparatus wherein the heating assembly is adapted to provide a responsive heat distribution to the fluid within the housing.

[19] A heating system, A heating assembly comprising a plurality of heating units, wherein at least one heating unit has a heating region that is independently controlled, and the heating assembly has a physical structure configured to deliver a variable power output per unit length along the length of the heating assembly, Multiple power conductors electrically connected to the heating unit, A power supply unit including a controller configured to modulate power to the independently controlled heating region via the power conductor 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, A heating system equipped with the following features.

[20] The heating system according to

[19] , further comprising means for determining the temperature.

[21] The heating system according to

[19] , further comprising means for determining heating conditions or heating requirements.

[22] A device for heating a fluid, A sealed housing having an internal chamber, a fluid inlet and a fluid outlet, The heating assembly comprises the heating system described in

[19] , which is located within the internal chamber of the housing, The apparatus wherein the heating assembly is adapted to provide a responsive heat distribution to the fluid within the housing.

Claims

1. A heating system, It is a heated bundle, A plurality of heating assemblies, wherein at least one of the heating assemblies comprises a plurality of heating units, at least one heating unit having an independently controlled heating region, the at least one heating assembly comprises a physical structure located on one of the plurality of heating units, thereby, due to the presence of the physical structure, one of the plurality of heating units has a different structure from an adjacent heating unit, and the physical structure is such that one of the plurality of heating units delivers a different power output per unit length from an adjacent heating unit, A heating bundle including a plurality of power conductors electrically connected to the plurality of heating units, Means for determining temperature, A power supply unit including a controller configured to modulate power to the independently controlled heating region via the power conductor based on the determined temperature in order to provide a desired power output along the length of the at least one heating assembly, A heating system equipped with the following features.

2. The heating system according to claim 1, wherein the physical structure includes a resistance heating element having various pitches that vary along the length of the resistance heating element within one of the plurality of heating units.

3. The heating system according to claim 2, wherein the various pitches are continuously varied along the length of the resistive heating element.

4. The heating system according to claim 1, wherein the physical structure includes a resistance heating element having various cross-sectional areas that vary along the length of the resistance heating element within one of the plurality of heating units.

5. The heating system according to claim 1, wherein the physical structure includes a resistance heating element having various cross-sectional areas and various pitches within one of the plurality of heating units.

6. The heating system according to claim 1, wherein the physical structure includes a plurality of parallel circuits within one of the plurality of heating units.

7. The heating system according to claim 1, wherein the physical structure is provided in two or more of the plurality of heating units.

8. The heating system according to claim 1, wherein the physical structure includes a composite heating element having a higher electrical resistivity closer to an adjacent heating unit or the end of the at least one heating assembly, and a lower electrical resistivity closer to another opposing adjacent heating unit.

9. The heating system according to claim 1, wherein the physical structure is provided in two or more of the heating assemblies.

10. The heating system according to claim 1, wherein at least one of the plurality of heating assemblies is a cartridge heater.

11. The heating system according to claim 1, wherein the physical structure includes one of the plurality of heating units having a different cross-sectional area from adjacent heating units.

12. The heating system according to claim 1, wherein the heating unit includes a plurality of resistive heating elements, and at least one of the resistive heating elements functions as a sensor.

13. The heating system according to claim 1, wherein the physical structure includes a composite heating element having various electrical resistivityes that vary along the length of the composite heating element.

14. The heating system according to claim 13, wherein the various electrical resistivityes include higher electrical resistivity in proximity to adjacent heating units or the ends of the at least one heating assembly, and lower electrical resistivity in proximity to opposing adjacent heating units.

15. A device for heating a fluid, A sealed housing having an internal chamber, a fluid inlet and a fluid outlet, The heating system according to claim 1 comprises the heating bundle being located within the internal chamber of the housing, The apparatus wherein the heating bundle is adapted to provide a responsive heat distribution to the fluid within the housing.

16. A heating system, It is a heated bundle, A plurality of heating assemblies, wherein at least one of the heating assemblies comprises a plurality of heating units, at least one heating unit having an independently controlled heating region, the at least one heating assembly comprises a physical structure located on one of the plurality of heating units, thereby, due to the presence of the physical structure, one of the plurality of heating units has a different structure from an adjacent heating unit, and the physical structure is such that one of the plurality of heating units delivers a different power output per unit length from an adjacent heating unit, A heating bundle including a plurality of power conductors electrically connected to the heating unit, Means for determining at least one of heating conditions and heating requirements, A power supply unit including a controller configured to modulate power to the independently controlled heating region via the power conductor based on at least one of heating conditions and heating requirements in order to provide a desired power output along the length of the at least one heating assembly, A heating system equipped with the following features.

17. The heating assembly according to claim 16, wherein at least one of the heating conditions and heating requirements is selected from the group consisting of the lifespan of the heating unit, the reliability of the heating unit, the size of the heating unit, the cost of the heating unit, the flux of the heater, the characteristics and operation of the heating unit, the power output, the power input, and the total heat generated.

18. A device for heating a fluid, A sealed housing having an internal chamber, a fluid inlet and a fluid outlet, The heating system according to claim 16 comprises the heating assembly being located within the internal chamber of the housing, The apparatus wherein the heating assembly is adapted to provide a responsive heat distribution to the fluid within the housing.

19. A heating system, A heating assembly comprising a plurality of heating units, wherein at least one heating unit has a heating region that is independently controlled, and the heating assembly comprises a physical structure located on one of the plurality of heating units, thereby, due to the presence of the physical structure, the one of the plurality of heating units has a different structure from the adjacent heating units, and the physical structure is such that the one of the plurality of heating units delivers a different power output per unit length from the adjacent heating units, Multiple power conductors electrically connected to the heating unit, A power supply unit including a controller configured to modulate power to the independently controlled heating region via the power conductor 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, A heating system equipped with the following features.

20. The heating system according to claim 19, further comprising means for determining the temperature.

21. The heating system according to claim 19, further comprising means for determining heating conditions or heating requirements.

22. A device for heating a fluid, A sealed housing having an internal chamber, a fluid inlet and a fluid outlet, The heating system according to claim 19, wherein the heating assembly is located within the internal chamber of the housing, The apparatus wherein the heating assembly is adapted to provide a responsive heat distribution to the fluid within the housing.

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