JP7073329B2 - Adaptive control heater bundle and current leakage reduction method - Google Patents

Description

The present disclosure relates to an electric heater, and more particularly to a heater for heating a fluid flow such as a heat exchanger and its control.

The statements in this section merely provide background information relevant to this disclosure and may not constitute prior art.

The fluid heater may be in the form of a cartridge heater and has a rod configuration for heating the fluid flowing along or past the outer surface of the cartridge heater. The cartridge heater may be located inside the heat exchanger to heat the fluid flowing through the heat exchanger. If the cartridge heater is not properly sealed, moisture and liquid can enter the cartridge heater and contaminate the insulating material that electrically insulates the resistance heating element from the metal coating of the cartridge heater, resulting in dielectric breakdown. May break down. Moisture can also cause a short circuit between the power conductor and the outer metal coating. Failure of the cartridge heater can cause costly downtime for devices that use the cartridge heater.

In addition, during operation, some heaters may experience a "current leak", which is usually the flow of current to the ground. Current leakage through the insulator surrounding the conductor in the electric heater and this condition can cause an increase in voltage and overheating.

In one embodiment of the present disclosure, there is provided a method of controlling a heating system with at least one heater assembly, wherein the heater assembly comprises a plurality of heater units and each heater unit defines at least one independently controlled heating zone. Will be done. Power is supplied to each of the heater units via a power conductor electrically connected to each of the independently controlled heating zones of the heater unit, and this power is supplied to each of the independently controlled heating zones. Each of the reduced number of independently controlled heating zones receives voltage at once, or at least some independently controlled heating zones receive reduced voltage at all times. , Voltage is selectively supplied to each of the independently controlled heating zones.

In another embodiment, the heater assembly comprises a plurality of heater units, each heater unit having at least one independently controlled heating zone, each having at least one heater assembly, each independently controlled. The total area of the independently controlled heating zone, which powers each of the heater units via a power conductor electrically connected to each of the heating zones and receives a voltage at one time, is reduced or , Each of the independently controlled heating zones is selectively voltageed and independently controlled so that at least some of the independently controlled heating zones always receive a reduced voltage. A method of reducing current leakage in a heating system is provided that comprises adjusting the power supplied to each of the zones.

In another embodiment, a heater bundle with multiple heater assemblies and each independent heater unit, where each heater assembly comprises multiple heater units and each heater unit defines at least one independently controlled heating zone. A heater system is provided that comprises a plurality of electrically connected power conductors to each of the controlled heating zones. The power supply is voltage so that a reduced number of independently controlled heating zones receive a voltage at one time, or at least some of the independently controlled heating zones receive a reduced voltage at all times. Is selectively supplied to each of the independently controlled heating zones and is configured to regulate power to each of the independently controlled heating zones of the heater unit via multiple power conductors. To.

In yet another embodiment, a heater system with a heater assembly having a plurality of heater units is provided, each heater unit defining at least one independently controlled heating zone. The power conductor is electrically connected to each of the independently controlled heating zones of each heater unit, and the power supply unit supplies power to each of the independently controlled heater zones of the heater unit via the power conductor. Is configured to adjust. The voltage is independent so that a reduced number of independently controlled heating zones receive a voltage at one time, or at least some of the independently controlled heating zones always receive a reduced voltage. It is selectively supplied to each of the controlled heating zones.

Further scope will be apparent from the description provided herein. It should be understood that the description and examples are intended for purposes of illustration only and not to limit the scope of this disclosure.

To help fully understand the present disclosure, the various forms given as examples will be described with reference to the accompanying drawings.
FIG. 1 is a perspective view of a heater bundle configured according to the teachings of the present disclosure. FIG. 2 is a perspective view of the heater assembly of the heater bundle of FIG. FIG. 3 is a modified perspective view of the heater assembly of the heater bundle of FIG. FIG. 4 is a perspective view of the heater assembly of FIG. 3, with the outer coating of the heater assembly removed for clarity. FIG. 5 is a perspective view of the core body of the heater assembly of FIG. FIG. 6 is a perspective view of the heat exchanger including the heater bundle of FIG. 1, in which the heater bundle is partially disassembled from the heat exchanger in order to expose the heater bundle for purposes of illustration. FIG. 7 is a block diagram of a method of operating a heater system including a heater bundle configured according to the teachings of the present disclosure. The drawings described herein are for illustration purposes only and are by no means limiting the scope of the present disclosure.

The following description is, in practice, merely exemplary and is not intended to limit this disclosure, use or use.
As shown in FIG. 1, heater systems configured according to the teachings of the present disclosure are usually indicated by reference numeral 10. The heater system 10 includes a heater bundle 12 and a power supply device 14 electrically connected to the heater bundle 12. The power supply 14 includes a controller 15 that controls the power supply to the heater bundle 12. As used herein, "heater bundle" refers to a heater device that includes two or more physically different heating devices that can be controlled independently. Therefore, if one of the heating devices in the heater bundle fails or deteriorates, the remaining heating devices in the heater bundle 12 can continue to operate.

In one embodiment, the heater bundle 12 includes a mounting flange 16 and a plurality of heater assemblies 18 fixed to the mounting flange 16. The mounting flange 16 includes a plurality of openings 20 through which the heater assembly 18 penetrates. Although the heater assembly 18 is arranged in parallel in this embodiment, it should be understood that alternative locations / arrangements of the heater assembly 18 are within the scope of the present disclosure.

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

As shown in FIG. 2, the heater assembly 18 according to one form may be in the form of a cartridge heater 30. The cartridge heater 30 is a tubular heater, and is contained in a core body 32, a resistance heating wire 34 wound around the core body 32, a metal coating 36 containing the core body 32 and the resistance heating wire 34, and a metal coating 36. An insulating material 38 for filling a space to electrically insulate the resistance heating wire 34 from the metal coating 36 and thermally conducting heat from the resistance heating wire 34 to the metal coating 36 is usually provided. The core body 32 may be made of ceramic. The insulating material 38 may be compressed magnesium oxide (MgO). The plurality of power conductors 42 penetrate the core body 32 along the longitudinal direction and are electrically connected to the resistance heating wire 34. The power conductor 42 also penetrates the end 44 that seals the outer coating 36. In order to supply power from the external power supply device 14 to the resistance heating wire 32, the power supply conductor 42 is connected to the external power supply device 14 (see FIG. 1). FIG. 2 shows only two power conductors 42 penetrating the end 44, but three or more power conductors 42 can penetrate the end 44. The power conductor 42 may be in the form of a conductive pin. The various configurations and further structural and electrical details of the cartridge heater are described in detail in US Pat. Nos. 2,831,951 and 3,970,822, which are the same applicants as this application. And their contents are incorporated herein by reference in their entirety. Therefore, it should be understood that the embodiments presented herein are merely exemplary and should not be configured to limit the scope of this disclosure.

Alternatively, a plurality of resistance heating wires 34 and a plurality of pairs of power conductors 42 may be used to form a plurality of heating circuits that can be independently controlled in order to increase the reliability of the cartridge heater 30. Therefore, if one of the resistance heating wires 34 fails, the remaining resistance wires 34 may continue to generate heat without the entire cartridge heater 30 failing and without causing costly machine downtime. can.

As shown in FIGS. 3 to 5, the heater assembly 50 may be in the form of a cartridge heater having a configuration similar to that of FIG. 2, except for the number of cores used and the number of power conductors. More specifically, the heater assembly 50 includes a plurality of heater units 52 and an outer metal coating 54 including the plurality of heater units 52, respectively, together with the plurality of power conductors 56. In order to electrically insulate the heater unit 52 from the outer metal coating 54, an insulating material (not shown in FIGS. 3 to 5) is provided between the plurality of heat generating units 52 and the outer metal coating 54. ing. The plurality of heater units 52 include a core body 58 and a resistance heating element 60 surrounding the core body 58, respectively. The resistance heating element 60 of each heater unit 52 may define one or more heating circuits for defining one or more heating zones 62.

In this embodiment, each heater unit 52 defines one heating zone 62, and a plurality of heater units 52 in each heater assembly 50 are aligned along the longitudinal direction X. Therefore, each heater assembly 50 defines a plurality of heating zones 62 aligned along the longitudinal direction X. The core body 58 of each heater unit 52 defines a plurality of through holes / openings 64 to allow the power conductor 56 to penetrate. The resistance heating element 60 of the heater unit 52 is connected to the power supply conductor 56, and then the power supply conductor 56 is connected to the external power supply device 14. The power conductor 56 supplies electric power from the power supply device 14 to the plurality of heater units 50. By appropriately connecting the power supply conductor 56 to the resistance heating element 60, the resistance heating element 60 of the plurality of heating units 52 can be independently controlled by the controller 15 of the power supply device 14. Therefore, a failure of one resistance heating element 60 for a particular heating zone 62 does not affect the proper operation of the remaining resistance heating element 60 for the remaining heating zone 62. Further, the heater unit 52 and the heater assembly 50 may be replaceable for ease of repair or assembly.

In this embodiment, six power conductors 56 are used in each heater assembly 50 to power five independent electric heating circuits on the five heater units 52. Alternatively, six power conductors 56 may be connected to the resistance heating element 60 so as to define three completely independent circuits on the five heater units 52. Any number of power conductors 56 can be provided to form any number of independently controlled heating circuits and independently controlled heating zones 62. For example, seven power conductors 56 may be used to provide the six heating zones 62. Eight power conductors 56 may be used to provide the seven heating zones 62.

The power supply conductor 56 may include a plurality of power supply and power return conductors, a plurality of power supply return conductors and a single power supply conductor, or a plurality of power supply conductors and a single power supply return conductor. Assuming that the number of heater zones is n, the number of power supply and return conductors is n + 1.
Alternatively, more electrically different heating zones 62 may be generated through multiplexing by the controller 15 of the external power supply 14, polarity sensitive switching and other circuit connection configurations. Multiplexing of thermal arrangements or use of various arrangements to increase the number of heating zones in the cartridge heater 50 for a given number of power conductors (eg, a cartridge heater with 6 power conductors for 15 or 30 zones). Is disclosed in US Pat. Nos. 9,123,755, 9,123,756, 9,177,840, 9,196,513 and their related applications, which are referred to in this application. Transferred to the same applicant, their contents are incorporated herein by reference in their entirety.

In this structure, each heater assembly 50 includes a plurality of heating zones 62 that can be independently controlled to change the power output or heat distribution according to the length of the heater assembly 50. The heater bundle 12 includes a plurality of such heater assemblies 50. Therefore, the heater bundle 12 provides a plurality of heating zones 62 and an adjusted heat distribution to heat the fluid flowing through the heater bundle 12 to suit a particular application. The power supply 14 can be configured to regulate power to each of the independently controlled heating zones 62.

For example, the heating assembly 50 may define "m" heating zones, and the heater bundle may include "k" heating assemblies 50. Therefore, the heater bundle 12 may define m × k heating zones. The plurality of heating zones 62 in the heater bundle 12 include the life and reliability of the individual heater units 52, the size and cost of the heater unit 52, the local heater flux, the characteristics and operation of the heater unit 52, and the total power output. Is not limited to these, and can be controlled individually and dynamically according to the heating conditions and / or the heating requirements.

In each circuit, the temperature distribution and / or power is system parameters (eg manufacturing variation / tolerance, changes in environmental conditions, changes in inflow conditions such as inlet temperature, inlet temperature distribution, flow velocity, velocity distribution, fluid composition, fluid. It is individually controlled at the desired temperature or desired power level to adapt to fluctuations in heat capacity, etc.). More specifically, the heater unit 52 may not generate the same heat output even when operated at the same power level due to manufacturing variations in addition to the degree of change in heater deterioration over time. The heater unit 52 may be independently controlled to adjust the heat output according to the desired heat distribution. The individual manufacturing tolerances of the components of the heater system and the assembly tolerance of the heater system increase with the adjusted power of the power supply, in other words, due to the high fidelity of the heater control, of the individual components. Manufacturing margins need not be tight / narrow.

The heater unit 52 may include a temperature sensor (not shown) for measuring the temperature of the heater unit 52, respectively. When a hotspot in the heater unit 52 is detected, the power supply unit 14 reduces or reduces power to the specific heater unit 52 in which the hotspot is detected in order to avoid overheating or failure of the specific heater unit 52. You may turn it off. The power supply 14 may adjust the power to the heater unit 52 adjacent to the disabled heater unit 52 so as to compensate for the reduced heat output from the particular heater unit 52.

The power supply 14 is to turn off or reduce the power level supplied to any particular zone and increase the power to a heating zone adjacent to the particular heating zone where it is disabled and the heat output is reduced. , Multi-zone algorithms may be included. Careful adjustment of the power to each heating zone can improve the overall reliability of the system. By detecting the hotspot and controlling the power supply accordingly, the heater system 10 is improved in safety.

The heater bundle 12 with a plurality of independently controlled heating zones 62 can achieve improved heating. For example, some circuits on the heater unit 52 are nominally (or "standard") less than 100% (or average power level that is part of the power generated by the heater with the line voltage applied). ") It may be operated in a duty cycle. The lower duty cycle allows the use of resistance heating wires with larger diameters, thereby improving reliability.

Smaller zones typically employ thinner wire sizes to achieve a given resistance. Variable power control allows the use of larger wire sizes and adapts to lower resistance values while protecting the heater from overload with the duty cycle limitation associated with the power loss capacity of the heater.

The use of scale factors may be related to the capacity of the heater unit 52 or heating zone 62. The plurality of heating zones 62 allows for more accurate determination and control of the heater bundle 12. By using a particular scale factor for a particular heating circuit / zone, more aggressive (ie, higher) temperatures (or power levels) are possible in almost all zones, and thus more than the heater bundle 12. It leads to a small and low cost design. Such scale factors and methods are disclosed in US Pat. No. 7,257,464, which is assigned to the same applicant as this application, the contents of which are incorporated herein by reference in their entirety.

The size of the heating zones controlled by the individual circuits can be equal or different in order to reduce the total number of zones required to control the temperature or power distribution to the desired accuracy.
Referring back to FIG. 1, the heater assembly 18 is shown to be a single-ended heater, i.e., the conductive pin penetrates only one end of the heater assembly 18 in the longitudinal direction. The heater assembly 18 may penetrate the mounting flange 16 or partition (not shown) and be sealed to the flange 16 or partition. Therefore, the heater assembly 18 can be individually removed and replaced without removing the mounting flange 16 from the container or tube.

Alternatively, the heater assembly 18 may be a "same shape at both ends" heater. For homomorphic heaters, the metal coating is bent into a hairpin shape and the power conductor passes through the longitudinal ends of the metal coating and is sealed to a flange or partition so that the longitudinal ends of the metal coating pass. You may. In this configuration, the flange or divider must be removed from the housing or container before replacing the individual heater assembly 18.

As shown in FIG. 6, the heater bundle 12 is incorporated in the heat exchanger 70. The heat exchanger 70 includes a sealed housing 72 that defines an internal chamber (not shown) and a heater bundle 12 that is located within the internal chamber of the housing 72. The sealed housing 72 includes an inlet 76 and an outlet 78 through which fluid guided to the inside and outside of the inner chamber of the sealed housing 72 passes. The fluid is heated by the heater bundle 12 disposed within the sealed housing 72. The heater bundle 12 may be placed in either the cloth flow or the flow parallel to their length.

The heater bundle 12 is connected to an external power supply unit 14, which may include a power adjusting means such as a switching means or a variable transformer to adjust the power supplied to each zone. .. The power adjustment may be performed as a function of time or based on the detected temperature of each heating zone.

The resistance heating wire may serve as a sensor by using the resistance of the resistance wire to measure the temperature of the resistance wire and using the same power conductor to send the temperature measurement information to the power supply device 14. Means for detecting the temperature of each zone allow control of the temperature along the length of each heater assembly 18 within the heater bundle 12 (until the resolution of the individual zones is reduced). Therefore, additional temperature sensor circuits and detection means can be omitted, thereby reducing manufacturing costs. Direct measurement of heater circuit temperature eliminates or minimizes many measurement errors associated with the use of individual sensors, thus reducing heat flux in a given circuit while maintaining the desired reliability level of the system. This is a clear advantage when trying to maximize. The heating element temperature is a characteristic that has the greatest effect on the reliability of the heater. The use of resistors to act as both heaters and sensors is disclosed in US Pat. No. 7,196,295 assigned to the same applicant as this application, the contents of which are herein by reference. It is incorporated as it is.

Alternatively, the power conductor 56 may be made of a dissimilar metal such that the dissimilar metal power conductor 56 forms a thermocouple for measuring the temperature of the resistance heating element. For example, at least one set of power supply and power return conductors may include different materials such that a junction is formed between the different materials and the resistance heating element of the heater unit, the temperature of one or more zones. Used to determine. Utilizing "integrated" and "thermally high pair" detection, such as using different metals for the heater, leads to the generation of thermocouple-like signals. The use of an integrated pair of power conductors for temperature measurement is disclosed in US Application No. 14 / 725,537, which is assigned to the same applicant as this application, the contents of which are herein by reference. It is incorporated into the book as it is.

The controller 15 that regulates the power supplied to each zone may be a closed-loop automatic control system. The closed-loop automatic control system 15 receives temperature feedback from each zone and automatically and dynamically controls the power supply to each zone, thereby eliminating the need for continuous or frequent human monitoring and adjustment of the heater. Automatically and dynamically control the power distribution and temperature along the length of each heater assembly 18 in the bundle 12.

The heater units 52 disclosed herein include, but may be calibrated, using a variety of methods including, but not limited to, energizing and sampling each heater unit 52 to calculate its resistance. The calculated resistance can then be compared to the calibrated resistance to determine the resistance ratio, or subsequently a value for determining the actual heater unit temperature. Typical methods are disclosed in US Applications 5,280,422 and 5,552,998, which are assigned to the same applicant as this application, the contents of which are incorporated herein by reference in their entirety. ..

One form of calibration is to operate the heater system 10 in at least one mode of operation, controlling the heater system 10 to produce the desired temperature for at least one of the independently controlled heating zones 62. To collect and record data for at least one independently controlled heating zone 62 for the mode of operation, and then access the recorded data for independently controlled heating. It involves determining the operating specifications of a heating system with a reduced number of zones and then using a heating system with a reduced number of independently controlled heating zones. As an example, the data may include power level and / or temperature information in other operating data from the heater system 10 from which the data was collected and recorded.

In one variant of the present disclosure, the heater system may include a single heater assembly 18 rather than multiple heater assemblies within the bundle 12. The single heater assembly 18 may include a plurality of heater units 52, where each heater unit 52 defines at least one independently controlled heating zone. Similarly, the power conductor 56 is electrically connected to each of the independently controlled heating zones 62 of each heater unit 62, and the power supply is independently controlled by the heater unit via the power conductor 56. It is configured to adjust the power to each of the heater zones 62.

Referring to FIG. 7, the method 100 for controlling the heater system includes in step 102 including a heater bundle comprising a plurality of heater assemblies. Each heater assembly contains multiple heater units. Each heater unit defines at least one independently controlled heating circuit (and thus a heating zone). In step 104, power to each heater unit is supplied via a power conductor electrically connected to each of the independently controlled heating zones within each heater unit. In step 106, the temperature in each zone is detected. The temperature may be determined using changes in the resistance of the resistance heating element of at least one heater unit. The zone temperature may be initially determined by measuring the zone resistance (or, if the appropriate material is used, by measuring the circuit voltage).

The temperature value may be digitized. The signal may be transmitted to the microprocessor. In step 108, the measured (detected) temperature value may be compared to the target (desired) temperature in each zone. In step 110, the power supplied to each heater unit may be adjusted based on the measured temperature so as to reach the target temperature.

Optionally, this method may further include the use of scale factors to regulate the tuned power. The scale factor may be a function of the heating capacity of each heating zone. The controller 15 may include an algorithm, which potentially contains scale factors and / or mathematical models of the dynamic behavior of the system (including knowledge of system update times) and in each zone until the next update. Determine the amount of power provided (via duty cycle, firing phase angle, voltage modulation, or similar technique). The desired power may be converted into a signal, which is transmitted to a switch or other power regulator for controlling the power output to the individual heating zones.

In this embodiment, even if at least one heating zone is turned off due to an abnormal condition, the remaining zones continue to supply the desired wattage without failure. If an abnormal condition is detected in at least one heating zone, the power is adjusted to provide the desired heating zone to the operating heating zone. Even if at least one heating zone is turned off based on the determined temperature, the remaining zones will continue to supply the desired wattage. The power is adjusted to each of the heating zones as at least one function of the received signal, model and time function.

For safety or process control reasons, common heaters have a specific position of the heater above a given temperature due to unwanted chemical or physical reactions (combustion / fire / oxidation, coke boil, etc.) at a specific location. To prevent this, it is usually operated below the maximum permissible temperature. Therefore, this is usually adapted to conservative heater designs (eg, large heaters with low power densities and much lower heat flux added to most of their surface than may otherwise be possible). To.

However, the heater bundles of the present disclosure can measure and limit the temperature at any location within the heater, reducing the resolution to the order of the size of the individual heating zones. Hotspots large enough to affect the temperature of individual circuits can be detected.

The temperature of the individual heating zones is automatically adjusted and limited as a result, so the dynamic and automatic limit of the temperature of each zone is unlikely to exceed the desired temperature limit of any zone, this zone. And keep all other zones operating at optimal power / heat flux levels. This provides an advantage in high temperature limiting measurements with higher accuracy than current practices in which separate thermocouples are fastened to the coating of one of the elements in the bundle. The reduced margins and the ability to adjust the power to individual zones can be selectively and individually applied selectively and individually to the heating zones, thereby predetermined, rather than being applied to the entire heater assembly. The risk of exceeding the specified temperature limit is reduced.

The characteristics of the cartridge heater can change over time. This time-varying characteristic may require the cartridge heater to be designed separately for only one selected (worse case) flow type, so that the cartridge heater is in another flow condition. Then it may work in a semi-optimal state.

However, there is only one flow condition in a typical cartridge heater with dynamic control that lowers the power distribution across the bundle from multiple heating units in the heater assembly to core size resolution. In contrast to the power distribution, it is possible to achieve a power distribution optimized for various flow conditions. Therefore, the heater bundle of the present application allows an increase in the total heat flux for all other flow conditions.

In addition, variable power control can increase the flexibility of the heater design. The voltage can be separated from the resistance (to a large extent) in the heater design, and the heater may be designed with the maximum wire diameter compatible with the heater. This increases the ability for power loss for a given heater size and level of reliability (or heater life) and makes it possible to reduce the size of the bundle for a given total power level. The power in this device can be adjusted by the variable duty cycle which is part of the variable wattage control currently available or under development. The heater bundle can be protected by programmable (or optionally pre-programmed) limits on the duty cycle of a given zone to prevent "overload" of the heater bundle.

In yet another embodiment of the present disclosure, methods and devices for reducing current leakage are provided. One method of controlling the heating system includes at least one heater assembly, a heater assembly with a plurality of heater units, and each heater unit defining at least one independently controlled heating zone, as described above. Power is supplied to each heater unit via a power conductor electrically connected to each of the independently controlled heating zones in each heater unit, and is supplied to each of the independently controlled heating zones. The power is adjusted. To reduce current leakage, a reduced number of independently controlled heating zones receive voltage at one time, or at least some (or a subset) independently controlled heating zones have been reduced. The voltage from the power supply is selectively supplied to each of the independently controlled heating zones so that the voltage is always received. In one example, the voltage may be selectively supplied by a variable transformer.

The independently controlled zones can be switched in sequence, thus limiting the number of zones (and the cross-sectional area of the electrical insulator exposed to the potential). Leakage current can be reduced by similar ratios by limiting the number (and area) of zones receiving potential at any given time to a fraction of the total number of zones. For example, the zones of the heater bundle are divided into four groups (not necessarily geometrically contiguous), each of which covers about 1/4 of the total area of the heater. In addition, if the switching scheme is set so that power is turned on to one or less of the four zones in time at any given moment, the overall leakage current from the heater is quartered. It can be reduced to 1 (25% of its original value).

In order to achieve selective voltage supply, a magnification is adopted in one form. Magnifications may be adopted in accordance with the teachings of US Pat. No. 7,257,464 assigned to the same applicant as the present application, the entire contents of which are incorporated herein by reference in their entirety. Magnification is adopted for at least one of adjusting the tuned power, determining the magnitude of the voltage selectively supplied, and determining how long the voltage is selectively supplied. May be done.

Further, the magnification may be a function of the operating characteristics of the heating system. For example, the magnification is, in particular, the power consumption capacity of at least one independently controlled heating zone, the maximum permissible temperature of at least one independently controlled heating zone, and at least one independently controlled heating zone. Exposed heating area, thermal behavior model of the heating system, characteristics of the environmental system that produces the flow of fluid heated by the heater system, fluid flow across the heater assembly, at least one independently controlled heating zone. Area, electrical insulation resistance of at least one independently controlled heating zone, current leakage of at least one independently controlled heating zone, circuit resistance of at least one independently controlled heating zone, at least It can be a function of one independently controlled heating zone zone circuit EMF and at least one independently controlled heating zone dielectric constant.

In another embodiment, the multipliers are plural, the wattage, the magnitude of the voltage selectively supplied, and the voltage supplied to each heating zone by the use of the scaling function is less than the value produced by the full line voltage. A power limiting function that limits the value of one of the periods selectively supplied by the value of, the scaling function is the ratio between the desired value and the value of the full line voltage, and the power controller. The scaled output is supplied by multiplying the ratio output by the scaling function.

The order and / or location of the independently controlled heating zones to which the voltage is supplied in sequence may be of any variety depending on the requirements of the application. For example, the voltage may first be sequentially delivered around the heater or around the edges before being fed to the next independently controlled heating zone in other geometric regions. Further, the voltage may be sequentially supplied to different heating zones based on the resistance change of each heating zone.

In another embodiment, at least one heating zone is turned off based on the anomalous condition, while the remaining zones selectively continue to receive voltage.

In yet another embodiment, the rate of continuous voltage supply to each heating zone is adjusted based on at least one operating characteristic of at least one heating zone. Operating characteristics include, for example, the resistance of at least one heating zone, changes in temperature and resistance over time, the flow of fluid across the heater assembly, the area of the independently controlled heating zone, and at least one independently. Electrical insulation resistance of controlled heating zone, current leakage of at least one independently controlled heating zone, circuit resistance of at least one independently controlled heating zone, at least one independently controlled heating The zone circuit EMF of the zone may be the dielectric constant of at least one independently controlled heating zone, as well as the characteristics of the environmental system that produces the flow of fluid heated by the heater system.

The method according to this embodiment of the present disclosure to reduce leakage current may be applied to at least one heater assembly, the heater assembly comprising multiple heater units, each heater unit having at least an independently controlled heating zone. Determine one. The method can be employed, within the scope of the present disclosure, with any embodiment of the heater and heater system disclosed herein.

It should be noted that the present disclosure is not limited to the embodiments described and exemplified. A great variety of variants have been described, many of which are part of the knowledge of one of ordinary skill in the art. Without departing from the scope of protection of this disclosure and this patent, these and further modifications may be added to this description and drawings as well as any alternatives by technical equivalents.
The inventions described in the original claims of the present application are described below.
[1]
The heater assembly comprises multiple heater units, and each heater unit comprises at least one heater assembly that defines at least one independently controlled heating zone.
Power is supplied to each of the heater units via a power conductor electrically connected to each of the independently controlled heating zones of the heater unit.
The independent control heating zone receives a reduced voltage at a time, or the independently controlled heating zone of at least one subset always receives a reduced voltage. To regulate the power supplied to each of the independently controlled heating zones by selectively supplying a voltage to each of the independently controlled heating zones.
How to control the heating system, including.
[2]
Use a magnification for at least one of adjusting the tuned power, determining the magnitude of the voltage selectively supplied, and determining how long the voltage is selectively supplied.
The method according to [1].
[3]
Power consumption capacity of at least one independently controlled heating zone, maximum permissible temperature of at least one independently controlled heating zone, exposed heating area of at least one independently controlled heating zone, heating system Thermal behavior model, the characteristics of the environmental system that produces the flow of fluid heated by the heater system, the flow rate of the fluid across the heater assembly, the area of at least one independently controlled heating zone, at least one independent Electrical insulation resistance of at least one independently controlled heating zone, current leakage of at least one independently controlled heating zone, circuit resistance of at least one independently controlled heating zone, at least one independently controlled Use the magnification as a function of the zone circuit EMF of the heating zone and at least one of the dielectric constants of the at least one independently controlled heating zone.
The method according to [2].
[4]
The magnification is selected by wattage, the magnitude of the voltage selectively supplied, and multiple values where the voltage supplied to each heating zone by the use of the scaling function is less than the value produced by the full line voltage. A power limiting function that limits the value of one of the periods of time supplied, said scaling function is the ratio between the desired value and the value of the full line voltage, and the power controller is the scaling function. The method according to [2], wherein the scaled output is supplied by multiplying by the ratio output by.
[5]
The method according to [1], wherein a voltage is sequentially supplied to a predetermined geometric region of the independently controlled heating zone.
[6]
The method according to [1], wherein a voltage is sequentially supplied to different heating zones based on the resistance change of each heating zone.
[7]
The method according to [1], wherein at least one heating zone is turned off based on the abnormal condition, and at the same time, the remaining zones selectively continue to receive voltage.
[8]
The method according to [1], wherein the ratio of continuously supplying a voltage to each heating zone is adjusted based on the operating characteristics of at least one heating zone.
[9]
The operating characteristics are the resistance of at least one heating zone, changes in temperature and resistance over time, the flow rate of fluid across the heater assembly, the area of the independently controlled heating zone, and at least one independently controlled. Electrical insulation resistance of at least one independently controlled heating zone, current leakage of at least one independently controlled heating zone, circuit resistance of at least one independently controlled heating zone, at least one independently controlled heating zone. Described in [8], which is one of the characteristics of a zone circuit EMF, the dielectric constant of at least one independently controlled heating zone, and an environmental system that produces a flow of fluid heated by a heater system. the method of.
[10]
With one or more heater assemblies, each heater assembly comprises multiple heater units, each heater unit defining at least one independently controlled heating zone.
A plurality of power conductors electrically connected to each of the independently controlled heating zones of the heater unit.
The voltage is such that a reduced number of independently controlled heating zones receive a voltage at a time, or at least one subset of said independently controlled heating zones always receives a reduced voltage. To selectively supply power to each of the independently controlled heating zones and to regulate power to each of the independently controlled heating zones of the heater unit via the plurality of power conductors. With the configured power supply
A heater system equipped with.
[11]
The heater system according to [10], wherein the voltage is selectively supplied via a variable transformer.
[12]
At least one set of power supply and power return conductors is a different material such that a joint is formed between the different material and the resistance heating element of the heater unit and is used to determine the temperature of one or more zones. The heater system according to [10].
[13]
The heater system according to [10], wherein the number of heater zones is n and the number of power supply and return conductors is n + 1.
[14]
The heater system according to [10], wherein the power source sequentially supplies the voltage to a predetermined geometric region of the independently controlled heating zone.
[15]
The heater system according to [10], wherein the power supply sequentially supplies a voltage to different heating zones based on the resistance change of each heating zone.
[16]
The heater system according to [10], wherein the power source turns off at least one heating zone based on an abnormal condition, while the remaining zones selectively continue to receive voltage.

Claims (13)

The heater assembly comprises at least one heater assembly, the heater assembly comprising a plurality of heater units, each heater unit comprising at least one resistance heating element and defining at least one independently controlled heating zone. The heater assembly comprises an insulating material that electrically insulates the resistance heating element of the plurality of heater units.
Power is supplied to each of the heater units via a power conductor electrically connected to each of the independently controlled heating zones of the heater unit.
The independently controlled heating zone so that at least one subset of the independently controlled heating zone always receives a reduced voltage in order to reduce current leakage through the insulating material. A voltage is selectively supplied to each of the heater assemblies, and the heating is independently controlled so as to supply a desired heat distribution along the length of the heater assembly in order to heat the heating target outside the heater assembly. A method of controlling a heating system that involves adjusting the power supplied to each of the zones. The method of claim 1, wherein voltages are sequentially supplied to the independently controlled heating zones. The method according to claim 1, wherein a voltage is sequentially supplied to different heating zones based on the resistance change of each heating zone. The method of claim 1, wherein at least one heating zone is turned off based on the anomalous condition, while the remaining heating zones selectively continue to receive voltage. The method according to claim 1, wherein the ratio of continuously supplying a voltage to each heating zone is adjusted based on the operating characteristics of at least one heating zone. The operating characteristics are the resistance of at least one heating zone, changes in temperature and resistance over time, the flow rate of fluid across the heater assembly, the area of the independently controlled heating zone, and at least one independently controlled. Electrical insulation resistance of at least one independently controlled heating zone, current leakage of at least one independently controlled heating zone, circuit resistance of at least one independently controlled heating zone, at least one independently controlled heating zone. 5. The zone circuit EMF, which is one of the characteristics of an environmental system that produces a flow of fluid heated by a heater system, as well as a dielectric constant of at least one independently controlled heating zone. the method of. One or more heater assemblies, each heater assembly comprising a plurality of heater units, each heater unit comprising at least one resistance heating element and defining at least one independently controlled heating zone. The one or more heater assemblies comprising an insulating material that electrically insulates the resistance heating elements of the plurality of heater units.
A plurality of power conductors electrically connected to each of the independently controlled heating zones of the heater unit.
The independently controlled heating zone so that at least one subset of the independently controlled heating zone always receives a reduced voltage in order to reduce current leakage through the insulating material. A voltage is selectively supplied to each of the plurality of heater assemblies so as to supply a desired heat distribution along the length of the one or more heater assemblies in order to heat the heating target outside the one or more heater assemblies. A heater system comprising a power supply configured to regulate power to each of the independently controlled heating zones of the heater unit via a power conductor of the heater unit. The heater system according to claim 7, wherein the voltage is selectively supplied via a variable transformer. The plurality of power conductors include at least one set of power supply conductors and power return conductors made of different materials.
The heater system according to claim 7. The heater system according to claim 7, wherein the number of independently controlled heating zones is n and the number of power conductors is n + 1. The heater system according to claim 7, wherein the power supply device sequentially supplies the voltage to the independently controlled heating zone. The heater system according to claim 7, wherein the power supply device sequentially supplies a voltage to different heating zones based on a change in resistance of each heating zone. The heater system of claim 7, wherein the power supply turns off at least one heating zone based on an abnormal condition, while the remaining heating zones continue to selectively receive voltage.

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