JP7374922B2 - Resistive heater with temperature sensing power pin and auxiliary sensing junction - Google Patents

Description

TECHNICAL FIELD This disclosure relates to temperature sensing devices such as resistive heaters and thermocouples.

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

Resistive heaters are used in a variety of applications to provide heat to targets and/or environments. One type of resistance heater known in the art is a cartridge heater, which typically consists of a resistance wire heating element wrapped around a ceramic core. A standard ceramic core defines two longitudinal bores within which power/terminal pins are placed. A first end of the resistance wire is electrically connected to one power supply pin, and the other end of the resistance wire is electrically connected to the other power supply pin. This assembly is then inserted into a larger diameter tubular metal sheath having an open end and a closed end, or two open ends, thus connecting the sheath and the resistance wire/core assembly. Create an annular space. An insulating material, such as magnesium oxide (MgO), is poured into the open end of the sheath to fill the annular space between the resistance wire and the inner surface of the sheath.

The open end of the sheath is sealed, for example by using a potting compound and/or a separate sealing member. The diameter of the sheath is then reduced to at least partially crush the ceramic core so that the MgO is compacted and compressed, collapsing the core around the pin to ensure good electrical contact and heat transfer. To collapse, the entire assembly is compacted or compressed by swaging or other suitable process. The compressed MgO provides a relatively good thermal conduction path between the heating element and the sheath, and also electrically insulates the sheath from the heating element.

A separate temperature sensor, such as a thermocouple, is placed on or near the heater to determine the appropriate temperature at which the heater should operate. Adding separate temperature sensors to the heater and its environment can be costly and add complexity to the overall heating system.

This section provides a general overview of the disclosure and is not an exhaustive disclosure of its entire scope or all of its features.

In one form, the present disclosure is directed to a heater that includes a resistive heating element, a first power pin, and a second power pin. The first power pin forms a first junction with the first end of the resistive heating element. The second power pin includes a first lead wire and a second lead wire. The first lead forms a second junction with the second end of the resistive heating element and defines a first electrically conductive material. The second lead forms a main sensing junction with the first lead at the first reference area. The second lead defines a second electrically conductive material different from the first electrically conductive material for measuring the temperature of the first reference area based on the voltage change generated by the main sensing junction.

In another form, the first power pin, the first lead of the second power pin, and the resistive heating element are made of the same material.

In yet another form, the first and second leads are different nickel alloys.

In one form, the first leads of the first power pin and the second power pin are made of the same material.

In another form, the heater further includes a controller in communication with the first power pin and the second power pin. The controller is configured to switch between a heating mode for directing power to the resistive heating element and a measurement mode for measuring voltage changes produced by the primary sensing junction to determine a temperature of the first reference area. configured.

In yet another form, the heater is in communication with the first and second power pins and configured to measure the change in voltage at the first and second junctions without interrupting power to the resistive heating element. The controller further includes a controller.

In one form, the Seebeck coefficients of the first power pin, the first lead of the second power pin, and the resistive heating element are substantially the same.

In another form, the primary sensing junction is located along the resistive heating element between the first end and the second end of the resistive heating element.

In yet another form, the main sensing junction is located outside the heater.

In one form, the first power pin includes a third lead and a fourth lead. A third lead is connected to the first end of the resistive heating element to form a first junction and define a first electrically conductive material. The fourth lead forms a second main sensing junction with the third lead at a second reference area adjacent and proximate to the first reference area. The fourth lead is different from the first conductive material and the second conductive material to function as a thermocouple and is connected to the main sensing junction to determine the temperature between the first and second reference areas. A third electrically conductive material to be used with the third conductive material is defined.

In one form, the Seebeck coefficients of the first lead of the second power pin, the third lead of the first power pin, and the resistive heating element are substantially the same.

In another form, the heater further includes a heat diffuser positioned around the main sensing junction.

In yet another form, the heater further includes a non-conductive portion, a sheath, and a sealing member. A non-conductive portion defines a proximal end and a distal end. The non-conductive portion has first and second openings extending through at least the proximal end. First and second power pins are disposed within the first and second openings, and a resistive heating element is disposed about the non-conductive portion. A sheath surrounds the non-conductive portion, and a sealing member is disposed at a proximal end of the non-conductive portion and extends at least partially within the sheath.

In one form, the present disclosure is directed to a heater that includes a resistive heating element, a first power pin, and a second power pin. The resistive heating element is operable in heating mode and measurement mode. In the measurement mode, the resistive heating element senses temperature at a first reference area along the resistive heating element. The first power pin forms a first junction with the first end of the resistive heating element. The second power pin includes a first lead wire and a second lead wire. The first lead forms a second junction with the second end of the resistive heating element and defines a first electrically conductive material. The second lead forms a main sensing junction with the first lead at the second reference area. The second lead defines a second electrically conductive material different from the first electrically conductive material for measuring the temperature of the second reference area based on the voltage change produced by the main sensing junction.

In another form, the heater further includes a controller in communication with the first power pin and the second power pin. The controller has a heating mode for directing a power source to the resistive heating element, a first reference area for measuring the resistance of the resistive heating element to determine the temperature, and a second reference area for determining the temperature. and a measurement mode for measuring changes in the voltage generated by the main sensing junction. The controller is configured to calculate the temperature of the third reference area based on the temperature of the first reference area, the temperature of the second reference area, the shape of the heater, and the power supplied to the heating element. Ru.

In one form, the controller is configured to adjust the heating element using the temperature measured by the primary sensing junction.

In yet another form, the primary sensing junction is formed along a different plane than that of the heating element.

In one form, the first power pin, the first lead of the second power pin, and the resistive heating element define one or more electrically conductive materials having substantially the same Seebeck coefficient.

In one form, the present disclosure is directed to a heater that includes a resistive heating element, a first power pin, and a second power pin. The first power pin forms a first junction with the first end of the resistive heating element. The second power pin includes a first lead wire and a second lead wire. The first lead forms a second junction with a second end of the resistive heating element. The second lead forms a main sensing junction with the first lead at the reference area. The restive heating element, the first power pin, and the first lead are made of a first electrically conductive material. The second lead is made of a second electrically conductive material having a different Seebeck coefficient than the first electrically conductive material to measure the temperature in the reference area based on the voltage change generated by the main sensing junction. ing.

In another form, the primary sensing junction is located along the resistive heating element between the first end and the second end of the resistive heating element.

In yet another form, the main sensing junction is located outside the heater.

Further areas of applicability will become apparent from the description provided herein. It is to be understood that the descriptions and specific examples are for illustrative purposes only and are not intended to limit the scope of the disclosure.

In order that the present disclosure may be fully understood, reference will now be made to the following accompanying drawings, in which various forms thereof are given by way of example.
FIG. 1 is a side cross-sectional view of a resistive heater with dual purpose power pins constructed in accordance with the teachings of the present disclosure. FIG. 2 is a perspective view of the resistive heater and lead controller of FIG. 1 constructed in accordance with the teachings of the present disclosure. FIG. 3 is a circuit diagram illustrating switching circuitry and measurement circuitry configured in accordance with one aspect of the present disclosure. FIG. 4 is a side cross-sectional view of an alternative form of a heater constructed in accordance with the teachings of the present disclosure and having multiple heating zones. FIG. 5 is a side view of an alternative form of the present disclosure illustrating a plurality of heaters constructed in accordance with the teachings of the present disclosure and connected in sequence. FIG. 6 is a side cross-sectional view of another form of a heater constructed in accordance with the teachings of the present disclosure and having a resistive element with a continuously variable pitch. FIG. 7 is a side cross-sectional view of another form of a heater constructed in accordance with the teachings of the present disclosure and having resistive elements with different pitches in multiple heating zones. FIG. 8 is a side cross-sectional view of a heat exchanger constructed in accordance with the teachings of the present disclosure and employing a heater. FIG. 9 is a side cross-sectional view illustrating a layered heater constructed in accordance with the teachings of the present disclosure and employing dual purpose power pins. FIG. 10 is a flow diagram illustrating a method in accordance with the teachings of the present disclosure. FIG. 11 is a perspective view of a heater constructed in accordance with the teachings of the present disclosure for use in fluidized immersion heating. FIG. 12 is a side cross-sectional view of a portion of the heater of FIG. 11 in accordance with the teachings of the present disclosure. FIG. 13 is a graph illustrating example differences in temperature at various junctions of the heater of FIG. 10 in accordance with the teachings of the present disclosure. FIG. 14 is a perspective view of another form of the present disclosure constructed in accordance with the teachings of the present disclosure and having multiple heater cores within a zone. FIG. 15 illustrates a heater with a main sensing junction according to the teachings of the present disclosure. FIG. 16 illustrates a heater with two main sensing junctions in accordance with the teachings of the present disclosure. FIG. 17A is a perspective view of a cartridge heater with a main sensing junction in accordance with the teachings of the present disclosure. FIG. 17B is a perspective view of a cartridge heater with a main sensing junction in accordance with the teachings of the present disclosure. FIG. 18 is a perspective view of a tubular heater having a main sensing junction and a two-wire heating element in accordance with the teachings of the present disclosure. FIG. 19 illustrates a main sensing junction with enhanced temperature measurement functionality in accordance with the teachings of the present disclosure. The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the disclosure in any way.

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

Referring to FIG. 1, a heater according to the teachings of the present disclosure is illustrated and generally designated by the reference numeral 20. As shown in FIG. Although this form of heater 20 is a cartridge heater, it is understood that the teachings of this disclosure may be applied to other types of heaters as described in more detail below while remaining within the scope of this disclosure. I want to be As shown, heater 20 includes a resistive heating element 22 having two end portions 24 and 26, resistive heating element 22 being in the form of a metal wire, such as a nichrome material, by way of example. The resistive heating element 22 is wrapped or placed around a non-conductive portion (or core in this form) 28. Core 28 defines a proximal end 30 and a distal end 32 and further defines first and second openings 34 and 36 extending at least through proximal end 30.

The heater 20 includes a first power supply pin 40 made of a first conductive material and a second power supply made of a second conductive material different from the first conductive material of the first power supply pin 40. It further includes a pin 42. Additionally, the resistive heating element 22 is made of a different material than the first and second electrically conductive materials of the first and second power pins 40, 42, and the first power pin 40 and the first and a second junction 52 with the second power pin 42 and the other end 26 . Because the resistive heating element 22 is of a different material than the first power pin 40 at junction 50 and the second power pin 42 at junction 52, a thermocouple junction is effectively formed and thus , a change in voltage at the first and second junctions 50, 52 is detected to determine the average temperature of the heater 20 without using a separate/separate temperature sensor (described in more detail below). To be).

In one form, the resistive heating element 22 is a nichrome material, the first power pin 40 is a Chromel® nickel alloy, and the second power pin 42 is an Alumel® nickel alloy. . Alternatively, first power supply pin 40 may be iron and second power supply 42 may be constantan. Any number of different materials and combinations thereof can be used for the resistive heating element 22, the first power pin 40, and the second power pin 42, as long as the three materials are different, and the thermocouple junction is , are effectively formed by junctions 50 and 52, as should be understood by those skilled in the art. The materials described herein are merely exemplary and therefore should not be construed as limiting the scope of the disclosure.

In one application, the average temperature of heater 20 can be used to detect the presence of moisture. If moisture is detected, rather than continuing to operate the heater 20 and potentially premature failure, a moisture management control algorithm may be implemented through the controller to remove moisture in a controlled manner. Yes (explained in more detail below).

As further shown, the heater 20 is disposed in a sheath 60 surrounding the non-conductive portion 28 and at a proximal end 30 of the non-conductive portion 28, at least partially within the sheath 60 to complete the heater assembly. Includes an extending sealing member 62. Additionally, a dielectric filler material 64 is disposed between the resistive heating element 22 and the sheath 60. Various configurations and further structural and electrical details of cartridge heaters are disclosed in U.S. Pat. No. 2,831,951 and U.S. Pat. No. 3,970,822 is described in further detail. Accordingly, it should be understood that the forms shown herein are merely illustrative and should not be construed as limiting the scope of the disclosure.

Referring now to FIG. 2, the present disclosure further includes a controller 70 in communication with the power supply pins 40, 42 and configured to measure changes in voltage at the first and second junctions 50, 52. More specifically, controller 70 measures millivolt (mV) changes at junctions 50 , 52 and then uses these voltage changes to calculate the average temperature of heater 20 . In one form, the controller 70 measures the change in voltage at the junctions 50, 52 without powering the electrical supply to the resistive heating element 22. This can be accomplished, for example, by taking readings at zero crossings of the AC input power signal. In another form, power is shut off and controller 70 switches from heating mode to measuring mode to measure changes in voltage. Once the average temperature is determined, controller 70 switches back to heating mode, which will be described in more detail below. More specifically, in one form, a triac is used to switch AC power to the heater 20, and temperature information is collected at or near the zero crossings of the power signal. Other forms of AC switching devices may be employed while remaining within the scope of this disclosure; therefore, the use of triacs is merely exemplary and should not be construed as limiting the scope of this disclosure.

Instead, as shown in FIG. 3, FET 72 is used as a switching device and means to measure voltage during the FET's off period with a DC power source. In one form, three relatively large resistors 73, 74, 75 are used to form a protection circuit for measurement circuit 76. It should be understood that this switching and measurement circuit is merely illustrative and should not be construed as limiting the scope of this disclosure.

Referring back to FIG. 2, a pair of leads 80 are connected to the first power pin 40 and the second power pin 42. In one form, both leads 80 are the same material, such as copper, for example. Lead wire 80 is provided to reduce the length of power pins required to reach controller 70 while introducing another junction with different materials at junctions 82 and 84. In this configuration, in order for the controller 70 to determine which junction is being measured for a change in voltage, the signal line 86 is connected such that the controller 70 switches between the signal lines 86 and 88 to identify the junction that is being measured. and 88 can be used. Alternatively, signal lines 86 and 88 may be removed and changes in voltage between lead junctions 82 and 84 may be ignored or compensated for via software in controller 70.

Referring now to FIG. 4, the teachings of the present disclosure may also be applied to a heater 20' having multiple zones 90, 92, 94. Each zone includes its own set of power pins 40', 42' and resistive heating elements 22', as described above (for clarity purposes, only one zone 90 is shown). In one form of this multi-zone heater 20', a controller 70 (not shown) operates at the ends 96, 98 of each zone to detect voltage changes and thereby determine an average temperature for that particular zone. , 100. Alternatively, controller 70 may communicate only with end 96 to determine the average temperature of heater 20' and whether moisture is present as described above. Although three zones are shown, it should be understood that any number of zones can be used while remaining within the scope of this disclosure.

Turning now to FIG. 5, the teachings of the present disclosure may be applied to a plurality of individual heaters 100, 102, 104, 106, 108, which may be cartridge heaters, in order as shown. Connected. Each heater comprises first and second junctions of different power pins to the resistive heating element as shown, so the average temperature of each heater 100, 102, 104, 106, 108 is as described above. This can be determined by the controller 70. In another form, each of the heaters 100, 102, 104, 106, 108 has its own power supply pin and a single power return pin to reduce the complexity of this multiple heater embodiment. is connected to all heaters. In this format with cartridge heaters, each core may include a passageway for accommodating the power supply pin of each successive heater.

Referring now to FIGS. 6 and 7, the pitch of resistive heating elements 110 can be varied in accordance with another form of the present disclosure to provide a tailored thermal profile along heater 120. In one form (FIG. 5), the resistive heating element 110 defines a continuously variable pitch along its length. More specifically, the resistive heating element 110 has a continuously variable pitch with the ability to accommodate an increasing or decreasing pitch P ₄ -P ₉ on immediately adjacent next 360 degree coil loops. The continuously variable pitch of the resistive heating elements 110 provides a gradual change in flux density at the heater surface (eg, the surface of the sheath 112). Although this continuously variable pitch principle is shown as applying to a tubular heater filled with insulation material 114, the principle also applies to any type of heater, including but not limited to the cartridge heaters described above. May be applied. Further, as described above, the first power pin 122 is made of a first conductive material, and the second power pin 124 is made of a second conductive material different from the first conductive material of the first power pin 122. is made of a conductive material, while the resistive heating element 110 is configured such that changes in voltage at the first and second junctions 126, 128 are detected to determine the average temperature of the heater 120. The first and second power supply pins 122 and 124 are made of a different material from the first and second conductive materials.

In another form (FIG. 7), the resistive heating elements 130 have pitches P ₁ , P ₂ , P ₃ in zones A, B, and C, respectively. P3 is larger than P1, and P1 is larger than P2. Resistive heating elements 130 have a constant pitch along the length of each zone as shown. Similarly, the first power pin 132 is made of a first conductive material, and the second power pin 134 is made of a second conductive material different from the first conductive material of the first power pin 132. while the resistive heating element 130 is connected to the first and second junctions such that a change in voltage at the first and second junctions 136, 138 is detected to determine the average temperature of the heater 120. The second power supply pin 132, 134 is made of a different material from the first and second conductive materials.

Referring to FIG. 8, the heater and dual purpose power pins described herein have a number of applications including, by way of example, heat exchanger 140. Heat exchanger 140 may include one or more heating elements 142, each of which may include a zonal or variable pitch resistance heating element as illustrated and described above while remaining within the scope of this disclosure. may further be included. The application of a heat exchanger is merely exemplary; the teachings of the present disclosure apply while also requiring temperature measurements, whether that temperature is unconditional or other environmental conditions, such as the presence of moisture, as discussed above. It should be understood that it can be used in any application where heat is provided.

The teachings of the present disclosure may be applied to other types of heaters, such as layered heater 150, as shown in FIG. Typically, layered heater 150 includes a dielectric layer 152 applied to substrate 154 , a resistive heating layer 156 applied to dielectric layer 152 , and a protective layer 158 applied over resistive heating layer 156 . A junction 160 is formed between one end of the trace resistive layer 158 and a first lead 162 (only one end is shown for clarity), as well as a second lead 162 (only one end is shown for clarity). Junctions are formed at the other end and, following the principles of the present disclosure as described above, voltage changes at these junctions are detected to determine the average temperature of heater 150. Such a layered heater is illustrated and described in further detail in US Pat. No. 8,680,443, which is hereby assigned to the assignee of the present invention and is incorporated herein by reference in its entirety.

Other types of heaters may also be used in accordance with the teachings of the present disclosure, instead of or in addition to cartridge, tubular, and laminar heaters as described above. These additional types of heaters may include, for example, polymer heaters, flexible heaters, heat tracing, and ceramic heaters. It is to be understood that these types of heaters are merely exemplary and should not be construed as limiting the scope of this disclosure.

Referring now to FIG. 10, a method of controlling at least one heater in accordance with the teachings of the present disclosure is illustrated. The method includes the following steps.

(A) a power supply pin made of a first conductive material for supplying power to the power supply pin; and a power return pin made of a conductive material different from the first conductive material for supplying power to the power return pin; Activates heating mode which returns power.

(B) powering a power supply pin and powering a resistive heating element having two ends and made of a material different from the first and second conductive materials of the power supply and return pin; The resistive heating element forms a first junction with the power supply pin at one end and a second junction with the power return pin at the other end, and also provides power through the power return pin.

(C) Measure the change in voltage at the first and second junctions to determine the average temperature of the heater.

(D) Based on the average temperature determined in step (C), adjust the power supplied to the heater as necessary.

(E) Repeat steps (A) to (D).

In another form of the method, step (B) is interrupted while the controller switches to a measurement mode for measuring the change in voltage, and then the controller switches back to the heating mode, as indicated by the dashed line.

Yet another form of the present disclosure is illustrated in FIGS. 11-13, which depict a heater for use in fluidized immersion heating, generally designated by the reference numeral 200. The heater 200 includes a heating section 202 configured for immersion in a fluid, the heating section 202 comprising a plurality of resistive heating elements 204 and at least two non-heating sections 206, 208 adjacent the heating section 202. (In FIG. 11, only one non-heating section 206 is shown). Each non-heating section 206 , 208 defines a length and includes a corresponding set of power pins electrically connected to the plurality of heating elements 204 . More specifically, each set of power pins includes a first power pin 212 made of a first conductive material and a second conductive material different from the first conductive material of the first power pin 212. A second power pin 214 is provided. The first power pin 212 is electrically connected to the second power pin 214 within the unheated portions 206, 208 to form junctions 220, 230, 240. As further shown, a second power pin 214 extends into the heating section 202 and is electrically connected to a corresponding resistive heating element 204. Furthermore, the second power pin 214 has a corresponding resistive heating at the connection between the second power pin 2 1 4 and the resistive heating element 204 so as not to generate another junction or a measurable amount of heat. Define a cross-sectional area larger than element 204.

As further shown, the termination section 250 is adjacent to the unheated section 206 and a plurality of first power pins 212 exit the unheated section 206 to provide electrical leads and to a controller (not shown). Extends into termination 250 for connection. Similar to the previous description, each of the resistive heating elements 204 is made of a different material than the first and second electrically conductive materials of the first and second power pins 212, 214, and the second power pin 214 Each of the junctions 220, 230, 240 of the first power pin 212 to the non-heated portions 206, 208 are located at different locations along the length of the non-heated portions 206, 208. More specifically, by way of example, junction 220 is at distance _L1 , junction 230 is at distance _L2 , and junction 240 is at distance _L3 .

As shown in FIG. 13, at the temperatures of junctions 220, 230, 240 over time "t", junction 220 is submerged in fluid F, junction 230 is submerged in fluid but not deeply, and junction 240 is not submerged. Accordingly, detecting changes in voltage at each of junctions 220, 230, 240 can provide an indication of fluid level for heating section 202. Particularly in cooking/frying applications where the fluid is oil, it is desirable that heating section 202 is not exposed to air during operation to avoid starting a fire. Using junctions 220, 230, 240 in accordance with the teachings of the present disclosure, the controller can determine whether the fluid level is too close to heating section 202 and therefore remove power from heater 200.

Although three junctions 220, 230, 240 are illustrated in this example, any number of junctions may be employed while remaining within the scope of this disclosure, provided that there are no junctions within heating section 202. I hope you understand that this is a good thing.

Referring now to FIG. 14, yet another form of the present disclosure includes a plurality of heater cores 300 arranged in zones of a heater system 270, as shown. Although this exemplary form of heater core 300 is a cartridge heater, as described above, it is to be understood that other types of heaters described herein may also be employed. Therefore, the cartridge heater structure in this form of the disclosure should not be construed as limiting the scope of the disclosure.

Each heater core 300 includes multiple power pins 301, 302, 303, 304, 305 as shown. Similar to the embodiments described above, the power pins are made of different conductive materials; more specifically, power pins 301, 304, and 305 are made of a first conductive material; 303 and 306 are made of a second conductive material different from the first conductive material. As further shown, at least one jumper 320 is connected between different power pins, in this example, power pin 301 and power pin 303, to obtain a temperature measurement near the location of jumper 320. Jumper 320 may, for example, be a lead wire or other electrically conductive member sufficient to obtain a millivolt signal indicative of the temperature proximate the location of jumper 320, which may also communicate with controller 70 as shown and described above. do. Any number of jumpers 320 may be used between different power pins; another location is illustrated with jumper 322 between power pins 303 and 305 between zones 3 and 4. .

In this exemplary form, power pins 301, 303, 305 are the neutral leg of the heater circuit between adjacent power pins 302, 304, 306, respectively. More specifically, the zone 1 heater circuit is between power supply pins 301 and 302 and includes a resistive heating element (eg, element 22 shown in FIG. 1) between these power supply pins. The zone 2 heater circuit is between power pins 303 and 304 and includes a resistive heating element between these two power pins. Similarly, the zone 3 heater circuit is between power pins 305 and 306 and includes a resistive heating element between these two power pins. It should be understood that these heater circuits are merely exemplary and are constructed in accordance with the cartridge heater teachings described above with reference to FIG.

Referring now to FIG. 15, in one form, heater 400 is configured to include a main sensing junction that can be placed within heater 400 or outside of heater 400 to measure temperature. Heater 400 includes a resistive heating element 402, a first power pin 404, and a second power pin 406. Resistive heating element 402 has a first end and a second end. A first power pin 404 is connected to the first end of the resistive heating element 402 to form a first junction 408 and a second power pin 406 forms a second junction 410. , is connected to the second end of the resistive heating element 402 . First power pin 404 and second power pin 406 function to provide power to heating element 402 via the controller.

Second power pin 406 includes a first lead 412 and a second lead 414 . A first lead 412 is connected to the second end of the resistive heating element 402 to form a second junction 410, and a second lead 414 is connected to the primary sensing element in the first reference area. It is connected to the first lead 412 to form a junction 416 . A second lead 414 is configured to connect the resistive heating element 402 to the controller via the first lead 412.

In one form, the first lead 412 and the second lead 414 are made of dissimilar electrically conductive materials or, more specifically, materials with different Seebeck coefficients. For example, various combinations of nickel alloys, iron, constantan, or Alumel may be used. The differences in the materials of the first lead 412 and the second lead 414 are represented by the different styles of lines in FIG. 15 (e.g., dashed lines for the second lead 414; (dotted-dash line). Because of the different materials, the main sensing junction 416 is effectively a thermocouple for producing a voltage change that is measured to determine the temperature at the first reference area. Thus, in this configuration, junctions 408 and 410 for connecting to resistive heating element 402 are separated from the sensing location. Thus, heater 400 is not limited to sensing temperature at the end of heating element 402; temperature measurements may be sensed at various locations within heater 400. Further, in one form, first lead 412 and second lead 414 are configured to have a main sensing junction 416 outside of heater 400.

As discussed with respect to FIG. 2, a controller (not shown in FIG. 15) communicates with a first power pin 404 and a second power pin 406 to provide power to the resistive heating element 402 via the power pins 404 and 406. configured to supply. The controller is also configured to utilize the Seebeck coefficient of the material to calculate the temperature at the first reference area based on the voltage change generated by the sensing junction 416.

In one form, the first leads 412 of the resistive heating element 402, the first power pin 404, and the second power pin 406 are made of the same electrically conductive material or have similar Seebeck properties (i.e., substantially the same Seebeck coefficient). ) made of materials with Therefore, the voltage changes produced by the first junction 408 and the second junction 410 are substantially zero, and the temperature measurements determined by the controller are based on the voltage changes produced by the main sensing junction 416.

In another form, the first lead 412 of the resistive heating element 402, the first power pin 404, and/or the second power pin 406 are made of different electrically conductive materials. In such a configuration, the material of the second lead 414 is such that the Seebeck coefficient of the second lead 414 is the same as that of the resistive heating element 402, the first power pin 404, and the first power pin 406 of the second lead 414. is selected to be most different from that of lead wire 412 of. Accordingly, the main sensing junction 416 is provided as having the largest contribution to the overall temperature measurement, and any temperature measurements from the first and second junctions 408 and 410 are minimized.

As discussed above, temperature can be detected at zero crossings of the power signal. Alternatively, the controller is configured to switch between a heating mode for directing power to the resistive heating element and a measurement mode for measuring changes in voltage at the primary sensing junction 416 to determine the temperature at the reference area. be done.

Referring to FIG. 16, in one form, heater 420 includes two sensing junctions in close proximity to each other to sense temperature at a virtual point between the two sensing junctions. Here, heater 420 includes a resistive heating element 422, a second power pin 424, and a first power pin 426. Resistive heating element 422 includes a first end and a second end. The first power pin 426 forms a first junction 428 with the first end of the heating element 422 and the second power pin 424 forms a second junction 430 with the second end of the heating element 422. form. The second power pin 424 is configured in a manner similar to the second power pin 406 of FIG. 432 and a second lead 434 connected to the first lead 432 to form a first primary sensing junction 440 at a first reference area within the heater 420 .

In this configuration, the first power pin 426 is configured in a similar manner to the second power pin 424 and has two leads (i.e., a third lead 436 and a fourth lead) to form a sensing junction. lead wire 438). More specifically, a third lead 436 is connected to the first end of the resistive heating element 422 to form a first junction 428, and a fourth lead 438 is connected to the first end of the resistive heating element 422 to form a first junction 428. A third lead wire 436 and a second main sensing junction 422 are formed in the reference area. A second primary sensing junction 422 is provided in a second reference area of the heater 420 adjacent and proximate to the first reference area having the first primary sensing junction 440 . Although sensing junctions 440 and 442 are provided within heater 420, sensing junctions 440 and 442 may also be provided outside heater 420.

Like the second power pin 424 , the third lead 436 is made of a different conductive material than that of the fourth lead 438 and is similar to the second lead 434 of the second power pin 424 . Made of a different conductive material. Thus, the second primary sensing junction 442 is effectively a thermocouple that is used in conjunction with the first primary sensing junction to determine the temperature between the first and second reference areas. Additionally, the resistors are configured such that the voltage change produced by the first junction 428 and the second junction 430 is substantially zero and the temperature measurement determined by the controller is based on the voltage change at the sensing junctions 440 and 442. The heating element 422, the first lead 432 of the second power pin 424, and the third lead 436 of the first power pin 426 are made of the same electrically conductive material or a material with similar Seebeck properties.

A controller (not shown in FIG. 16) provides power to the heating element 422 via a first power pin 426 and a second power pin 424, and based on the voltage changes produced by junctions 440 and 442, two The sensor is configured to measure temperature at a virtual point between two sensing junctions 440 and 442. In one form, the temperatures at the first and second reference areas are estimated to be substantially the same, and therefore the temperature detected by the controller is at a virtual point between the first and second reference areas. associated with.

Referring to FIGS. 17A and 17B, in one form, a primary sensing junction is provided in the cartridge heater to measure temperature at a virtual point outside the heater or at a reference area within the heater. FIG. 17A illustrates a cartridge heater 450 that includes a resistive heating element 452 in the form of a metal wire, a first power pin 454, and a second power pin 456. Cartridge heater 450 is configured to include two sensing junctions provided outside heater 450 to measure temperature at a virtual point between the two sensing junctions.

More specifically, in one form, the resistive heating element 452 is wrapped or disposed around a non-conductive portion (or core in this form) as discussed with respect to FIG. First power pin 454 includes a first lead 458 and a second lead 460. A first lead 458 is connected to a first end of the resistive heating element 452 to form a first junction 462 and a second lead 460 is connected to a first reference outside the heater 450. A first lead 458 and a first main sensing junction 464 are formed in the area. The second power pin 456 includes a third lead 466 and a fourth lead 468. A third lead 466 is connected to the resistive heating element 452 to form a second junction 470. A fourth lead 468 is connected to the third lead 466 to form a second primary sensing junction 472 at a second reference area outside of the heater 450 . The first and second main sensing junctions 464 and 472 are disposed adjacent and in close proximity to each other.

In one form, the resistive heating element 452, the first lead 458 of the first power pin 454, and the third lead 466 of the second power pin 456 are made of the same material or materials with similar Seebeck properties. The second lead wire 460 of the first power pin 454 and the fourth lead wire 468 of the second power pin 456 are made of a different material. Additionally, the material of the second lead wire 460 of the first power pin 454 is different from the material of the fourth lead wire 468 of the second power pin 456. Thus, the first and second main junctions 464 and 472 function as thermocouples to sense the temperature at a virtual point between the two junctions 464 and 472.

FIG. 17B illustrates a cartridge heater 480 with one main junction located within the heater. Cartridge heater 480 includes a resistive heating element 482 having two ends, a first power pin 484 and a second power pin 486. A first power pin 484 forms a first junction 488 with a first end of heating element 482 and a second power pin 486 forms a second junction 490 with a second end of heating element 482. form. Similar to the heater of FIG. 15, the second power pin 486 includes a first lead 492 and a second lead 494 that are made of different materials (ie, have different Seebeck coefficients). A first lead 492 is connected to a second end of the resistive heating element 482 to form a second junction 490 and a second lead 494 is connected to a first reference area within the heater 480. is connected to the first lead 492 to form a main sensing junction 496 . The main sensing junction 490 thus functions as a thermocouple for measuring the temperature of the first reference area.

In one form, the first lead 492 of the resistive heating element 482, the first power pin 484, and the second power pin 486 are made of the same electrically conductive material or a material with similar Seebeck properties. Therefore, the voltage changes produced by the first junction 488 and the second junction 490 are substantially zero, and the temperature measurements determined by the controller are based on the voltage changes produced by the main sensing junction 490. There is.

Referring to FIG. 18, the main sensing junction of the present disclosure may be used as part of a heat flux sensor to estimate the temperature between the inner surface of the heater and the outer surface of the heater. More specifically, in one form, the heater 500 functions to heat a fluid (e.g., gas) that passes through the tube and includes a resistive heating (i.e., thermal) element 502 (shown in very fine line). , a first power pin 504, and a second power pin 506. Although not fully shown in FIG. 18, a resistive heating element 502 is configured to extend through the heater 500 and is protected by a cover. A first power pin 504 and a second power pin 506 connect a first junction to a first end of heating element 502 and a second junction to a second end of heating element 502, respectively. It extends into the cover of the heater 500 to form a .

Resistive heating element 502 is a "two-wire" heating element such that it functions both as a heater and as a temperature sensor. Such two-wire functionality is disclosed, for example, in US Pat. No. 7,196,295, assigned to the assignee of the present invention herewith and incorporated herein by reference in its entirety. Typically, for two-wire systems, heating element 502 is made of a high temperature coefficient of resistance (TCR) material. A controller (not shown in FIG. 18) is configured to communicate with the first and second power pins 504 and 506 and to measure voltage (ie, mV) changes between the power pins 504 and 506. Using the voltage changes, the controller calculates the average temperature of the resistive heating element 502 (eg, around R1).

The first power pin 504 includes a first lead 508 and a second lead 510 that are made of different materials (ie, have different Seebeck coefficients). The first lead 508 forms a second junction with the heating element 502 and the second lead 510 runs along the outer surface (i.e., R2) of the heater 500 (i.e., with respect to that of the heating element 502). forming a primary sensing junction 512 with the first lead 508 in a second reference area (along a different plane); The main sensing junction 512 thus functions as a thermocouple to measure the temperature of the second reference area based on the voltage change generated by the sensing junction 512. The resistive heating element 502, the second power pin 506, and the first lead 508 of the first power pin 504 are made of the same material or are made of a material with similar Seebeck properties. There is.

In one form, the controller determines whether the inner surface of the heater 500 (i.e., the first reference area) and It is configured to estimate the temperature at a virtual point between the outer surfaces (second reference area). More specifically, the controller utilizes the voltage change between power pins 506 and 504 to determine the average temperature of the heating element in the first reference area, as described for the two-wire system. The controller further determines the temperature of the second reference area based on the voltage change produced by the main sensing junction 512 and the Seebeck coefficients of the first and second leads 508 and 510. Using the two measurement results, the supplied power, and the shape of the heater, the controller calculates the temperature in the third reference area at a desired position within the heater 500 (for example, any position within the heater). can do. Further, if the shape of the heater 500 is known, the controller can also be configured to determine the heat flux between the inner and outer surfaces of the heater 500. The heat flux can be used, for example, to detect cold fluid inlet areas, adjust temperature setpoints, and/or other appropriate system controls. Although heater 500 is illustrated as a tube, the heater may be configured in other suitable shapes (eg, a flat plate) and still be within the scope of this disclosure.

Further, in one form, before heater 500 is energized, heater 500 is at substantially room temperature and main sensing junction 512 is at the same or substantially the same temperature as the high TCR element line (i.e., heating element 502). become. The controller is configured to measure the temperature using the main sensing junction 512 and also to measure the resistance of the heating element 502. The controller uses this baseline value to relate the resistance of the heater 500 to the temperature measured by the primary sensing junction 512 and convert other resistances to temperature, thereby adjusting the heating element 502.

Referring to FIG. 19, the main sensing junction can be configured in a variety of suitable ways to improve temperature measurement along the surface. For example, in one form, the main sensing junction 550 is formed by a first lead 552 and a second lead 554 made of different materials. Sensing junction 550 has a planar shape (i.e., flat) and includes a heat diffuser that is a thermally conductive material (e.g., copper) to improve thermal contact with the surface and to diffuse the heat coming from the heating element. 556.

The primary sensing junction of the present disclosure functions as a thermocouple to enable temperature measurements at different locations within the heater and even outside the heater. Therefore, temperature measurements are not limited to the ends of the heating element. Additionally, the heater does not require a separate temperature sensor, reducing the complexity of the heater.

It is noted that the present disclosure is not limited to the embodiments described and illustrated by way of example. A wide variety of modifications have been described and many more are part of the knowledge of those skilled in the art. These and further improvements and any substitutions by technical equivalents may be added to the description and drawings without departing from the scope of the disclosure and protection of this patent.
Below, the invention described in the original claims of the present application will be added.
[1]
A heater,
a resistive heating element;
a first power pin forming a first junction with a first end of the resistive heating element;
a second power supply pin, the second power supply pin comprising:
a first lead forming a second junction with a second end of the resistive heating element and defining a first electrically conductive material;
a second lead forming a main sensing junction with the first lead in a first reference area, wherein the second lead is configured to: In order to measure the temperature of the first reference area, a second conductive material different from the first conductive material is defined.
[2]
The heater according to [1], wherein the first power pin, the first lead wire of the second power pin, and the resistance heating element are made of the same material.
[3]
The heater according to [1], wherein the first lead wire of the first power pin and the second lead wire of the second power pin are made of the same material.
[4]
further comprising a controller in communication with the first power pin and the second power pin, the controller for determining a heating mode for directing power to the resistive heating element and a temperature of the first reference area. The heater according to [1], wherein the heater is configured to switch between a measurement mode for measuring a voltage change generated by the main sensing junction and a measurement mode for measuring a voltage change generated by the main sensing junction.
[5]
The heater of [4], wherein the controller is configured to adjust the resistive heating element using the temperature measured by the main sensing junction.
[6]
The resistive heating element is operative to sense a temperature of a second reference area along the resistive heating element, and the controller is configured to operate the resistive heating element to determine a temperature of the second reference area. The heater according to [4], which measures the resistance of the heater.
[7]
The controller calculates the temperature of the third reference area based on the temperatures of the first reference area and the second reference area, the shape of the heater, and the electric power supplied to the heater element. The heater according to [6], comprising:
[8]
further comprising a controller in communication with the first and second power pins and configured to measure changes in voltage at the first and second junctions without interrupting power to the resistive heating element; 1].
[9]
The heater according to [1], wherein the Seebeck coefficients of the first power pin, the first lead wire of the second power pin, and the resistive heating element are substantially the same.
[10]
The heater according to [1], wherein the main sensing junction is located along the resistive heating element between the first end and the second end of the resistive heating element.
[11]
The heater according to [1], wherein the main sensing junction is arranged outside the heater.
[12]
The first power pin is
a third lead connected to the first end of the resistive heating element to form the first junction and define the first electrically conductive material;
a fourth lead forming a second main sensing junction with the third lead in a second reference area adjacent and proximate to the first reference area, the fourth lead forming a second main sensing junction with the third lead; a third electrically conductive material different from the first electrically conductive material and the second electrically conductive material for use in conjunction with the main sensing junction to determine the temperature between the areas and to function as a thermocouple; The heater according to [1], comprising a fourth lead wire.
[13]
According to [9], the Seebeck coefficients of the first lead of the second power pin, the third lead of the first power pin, and the resistive heating element are substantially the same. Heater listed.
[14]
The heater according to [1], further comprising a heat diffuser disposed around the main sensing junction.
[15]
a non-conductive portion defining a proximal end and a distal end, the non-conductive portion having first and second openings passing through at least the proximal end; a power pin is disposed within the first and second openings, and the non-conductive portion is surrounded by the resistive heating element;
a sheath surrounding the non-conductive part;
The heater according to [1], further comprising a sealing member disposed at the proximal end portion of the non-conductive portion and extending at least partially into the sheath.

Claims (15)

A heater,
a resistive heating element;
a first power pin forming a first junction with a first end of the resistive heating element;
a second power supply pin, the second power supply pin comprising:
a first lead forming a second junction with a second end of the resistive heating element and defining a first electrically conductive material;
a second lead forming a main sensing junction with the first lead in a first reference area, wherein the second lead is configured to: defining a second electrically conductive material different from the first electrically conductive material such that the main sensing junction functions as a thermocouple to measure the temperature of the first reference area ;
The temperature measured by the main sensing junction represents the overall temperature of the heater . The heater of claim 1, wherein the first power pin, the first lead of the second power pin, and the resistive heating element are made of the same material. The heater of claim 1, wherein the first lead wire of the first power pin and the second power pin are made of the same material. further comprising a controller in communication with the first power pin and the second power pin, the controller for determining a heating mode for directing power to the resistive heating element and a temperature of the first reference area. 2. The heater of claim 1, wherein the heater is configured to switch between a measurement mode and a measurement mode for measuring voltage changes generated by the main sensing junction. 5. The heater of claim 4, wherein the controller is configured to adjust the resistive heating element using the temperature measured by the primary sensing junction. The resistive heating element is operative to sense a temperature of a second reference area along the resistive heating element, and the controller is configured to operate the resistive heating element to determine a temperature of the second reference area. The heater according to claim 4, wherein the resistance of the heater is measured. The controller calculates the temperature of the third reference area based on the temperatures of the first reference area and the second reference area, the shape of the heater, and the electric power supplied to the heater element. 7. The heater of claim 6, comprising: Claim 1, further comprising a controller in communication with the first and second power pins and configured to measure voltage changes produced by the primary sensing junction without interrupting power to the resistive heating element. The heater described in. The heater of claim 1 , wherein the Seebeck coefficients of the first power pin, the first lead of the second power pin, and the resistive heating element are substantially the same. The heater of claim 1 , wherein the primary sensing junction is located along the resistive heating element between the first end and the second end of the resistive heating element. The heater of claim 1, wherein the main sensing junction is located outside the heater. The first power pin is
a third lead connected to the first end of the resistive heating element to form the first junction and define the first electrically conductive material;
a fourth lead forming a second main sensing junction with the third lead in a second reference area adjacent and proximate to the first reference area, the fourth lead forming a second main sensing junction with the third lead; a third electrically conductive material different from the first electrically conductive material and the second electrically conductive material for use in conjunction with the main sensing junction to determine the temperature between the areas and to function as a thermocouple; The heater according to claim 1, further comprising a fourth lead wire. 13. The Seebeck coefficients of the first lead of the second power pin, the third lead of the first power pin, and the resistive heating element are substantially the same. Heater listed. The heater of claim 1 further comprising a heat diffuser disposed around the main sensing junction. a non-conductive portion defining a proximal end and a distal end, the non-conductive portion having first and second openings passing through at least the proximal end; a power pin is disposed within the first and second openings, and the non-conductive portion is surrounded by the resistive heating element;
The heater of claim 1 , further comprising: a sheath surrounding the non-conductive portion; and a sealing member disposed at the proximal end portion of the non-conductive portion and extending at least partially into the sheath.

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