Heater Design for Carbon Allotrope Anti-Icing System

Abstract

An anti-icing system for an aircraft component includes a plurality of heaters. The aircraft component has at least two sections and a joint area. At least one of the heaters is an H-shaped carbon allotrope heater designed to apply heat to the joint area and prevent ice from accumulating in the joint area.

Description

Technical Field

[0001] The present application relates generally to anti-icing and, in particular, to anti-icing heaters. Background Art

[0002] Aircraft flying in the air are often subject to ice accumulation and must use anti-icing or de-icing devices to remove or prevent ice from accumulating on the exterior surfaces of the aircraft. For any type of electric heater or de-icing heater, the closer the heater is to the exterior surface of the wing, nacelle, nose cone, engine cowling or other aircraft part, the less power is required to heat or de-ice the aircraft component due to the heater's proximity to the exterior surface.

[0003] On aircraft, an electrothermal ice protection system (IPS) containing such a heater is applied to the back or embedded in the leading edge to provide the required heat to the leading edge surface, which would otherwise ice up. Due to the high thermal cooling load on the leading edge when the aircraft is in flight, heat does not easily diffuse from the IPS along the leading edge to the area directly below where there is no heater. For this reason, aircraft parts containing multiple sections, segments or strips that need to be broken in the leading edge surface are prone to ice formation at the joints or joint areas that are not covered by the edge of the IPS heater. Summary of the invention

[0004] In one embodiment, an ice protection system includes a first section, a second section attached to the first section by a joint, and a joint section, a first plurality of heaters extending spanwise across the first section, a second plurality of heaters extending spanwise across the second section, a first H-shaped heater on the first section extending to the joint section, and a second H-shaped heater on the second section extending to the joint section. The first section has a first span and a first chord. The second section has a second span and a second chord. The joint section includes a portion of the first section and a portion of the second section proximate to the portion of the first section.

[0005] In a second embodiment, an ice protection system includes: a component having a plurality of sections; and a plurality of heaters, each heater having at least one chord-wise section connected to a span-wise section. Each of the plurality of sections is connected to an adjacent section by a junction section. One of the plurality of heaters is located on each of the plurality of sections, and each of the chord-wise sections is located in the junction section.

[0006] In a third embodiment, an H-shaped heater includes: a first chord-wise segment; a second chord-wise segment parallel to the first chord-wise segment, wherein the first chord-wise segment and the second chord-wise segment are aligned; and a span-wise segment extending from a central region of the first chord-wise segment to a central region of the second chord-wise segment. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1is a schematic diagram of a heated leading edge with an ice protection system (IPS) in a prior art configuration.

[0008] Figure 2 is a schematic diagram of a heating front with an IPS including an H-shaped carbon allotrope heater.

[0009] Figures 3A to 3B is a schematic diagram of a heating front with an IPS including an H-shaped carbon allotrope heater in a first embodiment.

[0010] Figures 4A to 4B is a schematic diagram of a heating front with an IPS including an H-shaped carbon allotrope heater in a second embodiment. DETAILED DESCRIPTION

[0011] A heater having at least one chord-wise segment connected to a span-wise segment may be used on an aircraft component at or near a joint segment to allow complete heating coverage and ice protection. Such a heater may be H-shaped, T-shaped, or L-shaped. For example, an H-shaped heater has two chord-wise segments connected at their centers by a span-wise segment. Similarly, a T-shaped or L-shaped heater has a chord-wise segment connected to a span-wise segment. Such a configuration may mitigate the low temperatures at which component segments are joined to form a joint by allowing electrical connections to be made to the chord-wise segments assembled in such a joint segment. Such an approach may be particularly suitable for carbon allotropes, such as carbon nanotube (CNT)-based heater systems, because carbon allotropes systems allow electrical connections to be made at the ends of each segment of the heater.

[0012] Figure 1 is a schematic diagram of a heated leading edge 10 with an ice protection system (IPS) 11 in a prior art configuration. The IPS 11 includes a first section 12, a second section 14, a joining section 16, a heater 18 with electrical connections 20, and a cold section 22.

[0013] The first section 12 and the second section 14 of the leading edge may be, for example, panels on a wing joined at a joining section 16. A heater 18 is located on or embedded in the first section 12 and the second section 14 for anti-icing. The heater 18 may be, for example, a carbon allotrope-based heater, a metal heater, or other anti-icing system. The heater 18 extends across each of the component sections 12, 14 in the span direction S and heats a majority of the sections 12, 14. The heater 18 is electrically connected to a power source at an electrical connection 20.

[0014] However, the heater 18 cannot extend through the joint section 16 because the first section 12 and the second section 14 are manufactured as separate removable components; for example, they may need to be independently installed or removed during flight, or moved independently of each other, as is the case with the retractable slats. For this reason, during flight, when there is a high thermal cooling load on the IPS 10, the heater 18 cannot spread heat beyond the immediate area where they are located. This results in a cold section 22 near the joint section 16. In addition, the electrical connection 20 is the end of the heater 18, which is generally cooler than the body of the heater 18. For this reason, the electrical connection 20 on the heater 18 further contributes to the creation of the cold section 22. The cold section 22 will freeze because it is not heated. The formation of ice in the cold section 22 affects aerodynamics, wing operation, such as the powered slats, and acts as an anchor for further ice accumulation.

[0015] Figure 2 is a schematic diagram of a heated leading edge assembly 30 with an IPS 31 including an H-shaped carbon allotrope heater. The leading edge assembly 30 includes a first section 32 with an end portion 33, a second section 34 with an end portion 35, a joint section 36 with a joint 37, a linear heater 38, and an H-shaped heater 40.

[0016] Leading edge assembly 30 may be, for example, a leading edge on a wing. A leading edge is one example of a component to which IPS 31 may be applied. For example, IPS may be applied to the leading edge of a vertical stabilizer or horizontal stabilizer, or other components that contain joints and require uniform heating for ice protection.

[0017] The leading edge assembly 30 includes a first segment 32, a second segment 34 joined at a joining section 36. An end portion 33 of the first segment 32 and an end portion 35 of the second segment 34 are adjacent to each other and constitute the joining section 36. The joining section 36 includes a joint 37 where the first segment 32 and the second segment 34 meet. A linear heater 38 is located on the first segment 32 and the second segment 34 and heats the segments, but does not heat the portions 33, 35 that make up the joining section 36 around the joint 37. Instead, the H-shaped heater fills the space in the joining section 36 and heats near the joint 37 where the portion 33 of the first segment 32 and the portion 35 of the second segment 34 are joined. In some embodiments, the joint 37 can be a segment or intersection or one or more components or parts.

[0018] The H-shaped heater 40 facilitates ice protection and heating on the component sections 32, 34 including the joint section 36. The resistivity of the H-shaped heater 40 is between 0.005 ohms / square (Ω / sq) and 3.0 Ω / sq.

[0019] Each H-shaped heater 40 has two chordal sections of length L1 and width W2, connected centrally by a spanwise (S) section of width W1 (approximately twice the width W2 of the chordal sections). The chordal (C) sections are disposed on or embedded in the first and second sections 32, 34 so that they extend through the ends of the linear heater 38 into the joint section 36. This allows the chordal sections to be as close as possible to the joint in the joint section 36 and eliminates the need for reference. Figure 1 The cold section 22 is discussed.

[0020] The chord-wise section of the H-shaped heater 40 is electrically coupled to the span-wise section and operates in an anti-icing mode to prevent ice formation and growth. Various electrical configurations and specific geometries may be used to provide different heating curves, depending on the heating requirements of the component to which the H-shaped heater 40 is applied. Figures 3A to 3B and Figures 4A to 4B The physical and electrical layout of heater 40 is discussed in more depth.

[0021] The H-shaped heater 40 is made of a carbon allotrope material. For example, carbon nanotubes (CNTs) are allotropes of carbon with a roughly cylindrical nanostructure, which have a variety of uses in nanotechnology, electronics, optics, and other material sciences. In addition to being lightweight, CNTs are not only thermally conductive but also electrically conductive. Due to these properties, CNTs can be used as heaters to prevent ice formation on aircraft or other vehicles. Other carbon allotropes such as graphene or graphene nanoribbons (GNRs) can also be used for heating or deicing. Graphene has a two-dimensional honeycomb lattice structure and is much stronger than steel, but still has electrical and thermal conductivity. GNRs are graphene strips with ultra-thin widths, typically less than 50 nm each.

[0022] Carbon allotrope heaters are particularly beneficial for deicing due to their efficiency, light weight, ability to be molded into specific shapes, and durability. Compared to traditional metal heaters, they are more durable and can be more easily formed to specific application needs.

[0023] Figures 3A to 3B is a schematic diagram of a heating front with an IPS including an H-shaped carbon allotrope heater in a first embodiment. Figure 3A shows the physical layout of an IPS with an H-shaped carbon allotrope heater, and Figure 3B The electrical layout is shown.

[0024] Figure 3A is a schematic diagram of a heated leading edge assembly 50 having an IPS 51, a main section 52, a joint section 56, a linear heater 58, and an H-shaped heater 60. The H-shaped carbon allotrope heaters 60 used in the IPS system 51 each include a spanwise section 62, a chordwise section 64, a positive electrical connection 66, and a negative electrical connection 68.

[0025] The segments 52, 56 and the linear heater 58 are similar to those described with respect to Figure 2 The main section 52 has both a span and a chord. A linear heater 58 is applied to the main section 52 in the spanwise direction. The linear heater 58 does not reach the joint section 56.

[0026] The heater 60 uses an "H" type design including two chordal sections 64 and one spanwise section 62. The chordal sections 64 continue along the chord of the main section 52, while the spanwise sections 62 continue along the span of the main section 52. The chordal sections 64 have equal lengths and continue parallel to each other. The spanwise sections 62 connect the chordal sections 64 at the center of the chordal sections 64, thereby forming an "H" shape.

[0027] The chord-wise section 64 is adjacent to the edge of the joint in the joint section 56. This mitigates cold temperatures in the joint section 56 of the leading edge assembly 50. The chord-wise section 64 is electrically coupled to the span-wise section 62 and may operate in an anti-icing mode to prevent ice growth.

[0028] exist Figures 3A to 3B In the embodiment of the present invention, the chordal segments 64 carry electrical connections to the heater 60. The positive electrical connection 66 is located at the opposite end of the first chordal segment, and the negative electrical connection 68 is located at the opposite end of the second chordal segment. The electrical connections 66, 68 can be made by busbars, wires, solder paste or other suitable connecting materials that couple the heater 60 to a power source.

[0029] Figure 3B is a schematic diagram of the electrical configuration of the H-shaped heater 60 on the leading edge assembly 50. Here, the linear heater 58 is shown with a resistor 59. The H-shaped heater 60 is shown with a spanwise resistor 70 and chordwise resistors 72, 74, 76 and 78.

[0030] Resistors 59 are each spanwise and centrally located on one of the linear heaters 58. Each of the resistors 59 is equal to one another. Resistors 70 are located on the spanwise section 62 of the heater 60. Resistors 70 are equal to twice one resistor 59. Resistors 72, 74, 76, 78 are located on the chordwise section 64 of the heater 60. Each of the resistors 72, 74, 76, 78 is equal to one resistor 59.

[0031] This resistor configuration allows for consistent power across the entire IPS on the heater 60 and leading edge assembly 50. In some embodiments, this is achieved through constant current and constant resistance. Alternatively, this is achieved through variable current and variable resistance to produce constant power.

[0032] Figures 4A to 4Bis a schematic diagram of a heating front with an IPS including an H-shaped carbon allotrope heater in a second embodiment. Figure 4A shows the physical layout of an IPS with an H-shaped carbon allotrope heater, and Figure 4B The electrical layout is shown.

[0033] Figure 4A is a schematic diagram of a heated leading edge assembly 80 having an IPS 81, a main section 82, a joint section 86, a linear heater 88, and an H-shaped heater 90. The H-shaped carbon allotrope heater 90 used in the IPS system has a different electrical configuration than the heater 60. The heater 90 includes a spanwise section 92, a chordwise section 94, a positive electrical connection 96, and a negative electrical connection 98.

[0034] The segments 82, 86 and the linear heater 88 are similar to those described with respect to Figure 2 Those components discussed. The main section 82 has both span and chord. The linear heater 88 is applied to the main section 82 in the spanwise direction. The linear heater 88 does not reach the joint section 86.

[0035] The heater 90 uses an "H" type design including two chord-wise sections 94 and one span-wise section 92. This mitigates the low temperatures in the joint section 86 of the leading edge assembly 80. Herein, the "H" pattern of the heater 90 is a serpentine pattern that continues from the positive electrical connection 96 to the negative electrical connection 98 of the "H" shape. The benefit of this configuration is that the electrical connections are minimized while ensuring that the entire "H" is heated simultaneously. The electrical connections 96, 98 can be similar to those of reference Figure 3A Describe the way to connect.

[0036] Figure 4B is a schematic diagram of the electrical configuration of the H-shaped heater 90 on the leading edge assembly 80. The assembly 80 includes a linear heater 88 having a resistor 89 and an H-shaped heater 90 having a spanwise section 92, a chordwise section 94, connectors 96, 98, and resistors 100, 102, 104, 106, 108, 110, 112, and 114.

[0037] On the linear heaters 88, resistors 89 are each spanwise and centrally located on one of the linear heaters 88. Each of the resistors 89 is equal to one another. Resistors 100, 102, 104, 106, 108, and 110 are located on a chordwise portion of the heater 90. The lengths of resistors 100, 102, 106, and 108 are equal. Likewise, the lengths of resistors 104 and 110 are equal. Resistors 112 and 114 are located on a spanwise section of the heater 90. This electrical configuration allows for variable electrical power in the heater 90 and leading edge assembly 80. This can be accomplished with constant current and variable resistance.

[0038] Alternatively, the H-shaped heater can be replaced with a T-shaped or L-shaped heater. These heater shapes have at least one chord-wise segment that can be applied closely to the edge of the component segment so that the resulting joined segment is heated by the chord-wise segment. Each of these shaped heaters should also have at least one span-wise segment connected to at least one chord-wise segment. The span-wise segments allow electrical connection between chord-wise segments across the component surface.

[0039] A heater having at least one chord-wise section allows for the reduction of ice formation in a joint or joint section on an aircraft component. Ice formation, in addition to affecting aerodynamics, can interfere with normal wing operations, such as power slats. Ice formation can also act as an anchor and promote additional ice growth or "bridging" when ice is allowed to accumulate in the joint area. The use of such a heater simplifies ice protection by using a span-wise connecting section between two chord-wise sections. Due to this geometry, no additional electrical connections or circuits are required to heat the joint section.

[0040] Discussion of possible implementation plans

[0041] The following is a non-exclusive description of possible embodiments of the invention.

[0042] An anti-icing system includes a first section, a second section attached to the first section by a joint, and a joint section, a first plurality of heaters extending across the first section, a second plurality of heaters extending across the second section, a first H-shaped heater on the first section extending to the joint section, and a second H-shaped heater on the second section extending to the joint section. The first section has a first span and a first chord. The second section has a second span and a second chord. The joint section includes a portion of the first section and a portion of the second section proximate to the portion of the first section.

[0043] Additionally and / or alternatively, the system of the preceding paragraph may optionally include any one or more of the following features, configurations, and / or additional components:

[0044] The anti-icing system is applied to a component selected from the group consisting of: a wing leading edge, a vertical stabilizer leading edge, a horizontal stabilizer leading edge, a pylon, a wheel blade, a propeller, a blade, an engine inlet, and a surface requiring an adjacent heater.

[0045] The first and second H-shaped heaters each include two chord-wise sections connected by a span-wise section.

[0046] The first and second H-shaped heaters also include a resistor on the span-wise segment and two resistors on each of the chord-wise segments.

[0047] The resistivity of the first and second H-shaped heaters is between 0.005 ohms / square (Ω / sq) and 3.0 Ω / sq.

[0048] The first and second H-shaped heaters each include a material selected from the group consisting of: carbon nanotubes, graphene, graphene nanoribbons, and combinations thereof.

[0049] In each of the first and second H-shaped heaters, the electric power is constant.

[0050] The first and second H-shaped heaters also include two positive electrical connections, one each at an end of the first chord-wise segment, and two negative electrical connections, one each at an end of the second chord-wise segment.

[0051] In each of the first and second H-shaped heaters, the electric power is variable.

[0052] Each of the first and second H-shaped heaters includes a positive electrical connection at one end of the chord-wise segment and a negative electrical connection at the one end of the chord-wise segment.

[0053] An anti-icing system includes: a component having a plurality of sections; and a plurality of heaters, each heater having at least one chord-wise section connected to a span-wise section. Each of the plurality of sections is connected to an adjacent section by a junction section. One of the plurality of heaters is located on each of the plurality of sections, and each of the chord-wise sections is located in the junction section.

[0054] Additionally and / or alternatively, the system of the preceding paragraph may optionally include any one or more of the following features, configurations, and / or additional components:

[0055] The system includes a plurality of linear span-wise heaters on each of the plurality of segments, and wherein each of the plurality of linear span-wise heaters does not reach the joint segment.

[0056] Each of the plurality of heaters is H-shaped, T-shaped, or L-shaped.

[0057] Each of the plurality of H-shaped heaters also includes at least one positive electrical connection and at least one negative electrical connection.

[0058] An H-shaped heater includes: a first chord-wise section; a second chord-wise section parallel to the first chord-wise section, wherein the first chord-wise section and the second chord-wise section are aligned; and a span-wise section extending from a central region of the first chord-wise section to a central region of the second chord-wise section.

[0059] Additionally and / or alternatively, the heater of the preceding paragraph may optionally include any one or more of the following features, configurations and / or additional components:

[0060] The heater includes a material selected from the group consisting of carbon nanotubes, graphene, graphene nanoribbons, and combinations thereof.

[0061] The heater includes: a first positive electrical connection on a first end of a first chord-wise segment; a second positive electrical connection on a second end of the first chord-wise segment, wherein the second end is opposite the first end; a first negative electrical connection on the first end of the second chord-wise segment; and a second negative electrical connection on a second end of the second chord-wise segment, wherein the second end is opposite the first end.

[0062] The heater includes: a first resistor centered on the spanwise segment; a second resistor on the first chordwise segment centered between a first end of the first chordwise segment and the spanwise segment; a third resistor on the first chordwise segment centered between a second end of the first chordwise segment and the spanwise segment; a fourth resistor on the second chordwise segment centered between a first end of the second chordwise segment and the spanwise segment; and a fifth resistor on the second chordwise segment centered between a second end of the second chordwise segment and the spanwise segment.

[0063] The heater includes a positive electrical connection on the first end of the first chord-wise segment and a negative electrical connection on the first end of the first chord-wise segment.

[0064] The span-wise segments have a first width, and each of the chord-wise segments has a second width that is half the size of the first width.

[0065] Although the present invention has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and that equivalents may be substituted for its elements without departing from the scope of the present invention. In addition, many modifications may be made to adapt specific circumstances or materials to the teachings of the present invention without departing from the basic scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed, but the present invention will include all embodiments falling within the scope of the appended claims.

Claims

1. An anti-icing system for an aircraft component, comprising: a first section of an aircraft component having a first span and a first chord; a second section of the aircraft component having a second span and a second chord attached to the first section by a joint; and A joining section comprising: an end portion of a first section of the aircraft component; and an end portion of a second section of the aircraft component adjacent to an end portion of the first section of the aircraft component; a first plurality of heaters extending spanwise across a first section of the aircraft component and configured to heat the first section of the aircraft component; a second plurality of heaters extending spanwise across a second section of the aircraft component and configured to heat the second section of the aircraft component; a first H-shaped heater on the first section of the aircraft component extending into the joint section, wherein the first H-shaped heater has at least one chord-wise section connected to at least one span-wise section, and the at least one chord-wise section is positioned in the joint section such that the at least one chord-wise section is configured to heat an end portion of the first section of the aircraft component; and a second H-shaped heater on the second section of the aircraft component extending into the joint section, wherein the second H-shaped heater has at least one chord-wise section connected to at least one span-wise section, and the at least one chord-wise section is positioned in the joint section such that the at least one chord-wise section is configured to heat an end portion of the second section of the aircraft component.

2. The system of claim 1, wherein the anti-icing system is applied to a component selected from the group consisting of: a wing leading edge, a vertical stabilizer leading edge, a horizontal stabilizer leading edge, a pylon, a wheel blade, an engine inlet.

3. The system of claim 1, wherein the anti-icing system is applied to a propeller.

4. The system of claim 1, wherein the anti-icing system is applied to a blade.

5. The system of claim 1, wherein the anti-icing system is applied to a surface requiring an adjacent heater.

6. The system of claim 1, wherein the first and second H-shaped heaters each include two chord-wise sections connected by a span-wise section.

7. The system of claim 6, wherein each of the first and second H-shaped heaters further comprises a resistor on the spanwise segment and two resistors on each of the chordwise segments.

8. The system of claim 1, wherein each of the first and second H-shaped heaters has a resistivity between 0.005 ohms / square (Ω / sq) and 3.0 Ω / sq.

9. The system of claim 1, wherein the first and second H-shaped heaters each comprise a material selected from the group consisting of: carbon nanotubes, graphene, and combinations thereof.

10. The system of claim 1, wherein the first and second H-shaped heaters each comprise a graphene nanoribbon.

11. The system of claim 1, wherein in each of the first and second H-shaped heaters, electric power is constant.

12. The system of claim 11, wherein each of the first and second H-shaped heaters further comprises: two positive electrical connections, one each at an end of the first chordwise segment; and Two negative electrical connections are made, one each at an end of the second chordwise segment.

13. The system of claim 1, wherein in each of the first and second H-shaped heaters, electrical power is variable.

14. The system of claim 13, wherein each of the first and second H-shaped heaters further comprises: a positive electrical connection at one end of the chord-wise section; and A negative electrical connection is provided at the one end of the chord-wise segment.

15. An anti-icing system comprising: An aircraft component having a first aircraft component section and a second aircraft component section, wherein each of the first aircraft component section and the second aircraft component section are positioned adjacent to each other at a joining section and are separate movable components, wherein the joining section comprises: an end portion of a first aircraft component section; and an end portion of a second aircraft component segment adjacent to an end portion of the first aircraft component segment; and a first heater having at least one chord-wise segment connected to a span-wise segment positioned on the first aircraft component section and a second heater having at least one chord-wise segment connected to a span-wise segment positioned on the second aircraft component section, wherein at least one chord-wise segment of each of the first heater and the second heater is located in the joint section such that at least one chord-wise segment of each heater is configured to heat an end portion of the aircraft component section in which it is located.

16. The system of claim 15, further comprising a plurality of linear span-wise heaters on each of the plurality of aircraft component sections, and wherein each of the plurality of linear span-wise heaters does not reach the joint section.

17. The system of claim 15, wherein each of the plurality of heaters is H-shaped, T-shaped, or L-shaped.

18. The system of claim 15, wherein each of the plurality of heaters is an H-shaped heater and further comprises at least one positive electrical connection and at least one negative electrical connection.

19. An H-shaped heater for an aircraft component, comprising: first chordwise section; a second chord-wise segment parallel to the first chord-wise segment; and a span-wise section extending from a central region of the first chord-wise section to a central region of the second chord-wise section; wherein the aircraft component comprises a plurality of aircraft component sections, and each of the plurality of aircraft component sections is a separate movable assembly connected to an adjacent aircraft component section by a joining section; and The H-shaped heater is positioned on at least one of the plurality of aircraft component sections such that at least one of the chord-wise sections of the H-shaped heater is located in a joint section and at least one of the chord-wise sections of the H-shaped heater is configured to heat an end portion of the joint section.

20. The H-shaped heater of claim 19, wherein the heater comprises a material selected from the group consisting of: carbon nanotubes, graphene, and combinations thereof.

21. The H-shaped heater of claim 19, wherein the heater comprises graphene nanoribbons.

22. The H-shaped heater of claim 19, further comprising: a first positive electrical connection on a first end of the first chord-wise segment; a second positive electrical connection on a second end of the first chord-wise segment, wherein the second end is opposite the first end; a first negative electrical connection on a first end of the second chord-wise segment; and A second negative electrical connection is provided at a second end of the second chord-wise segment, wherein the second end is opposite the first end.

23. The H-shaped heater of claim 22, further comprising: a first resistor centered on the spanwise segment; a second resistor on the first chord-wise segment centered between the first end of the first chord-wise segment and the span-wise segment; a third resistor on the first chord-wise segment centered between the second end of the first chord-wise segment and the span-wise segment; a fourth resistor on the second chord-wise segment centered between the first end of the second chord-wise segment and the span-wise segment; and A fifth resistor on the second chordwise segment is centered between the second end of the second chordwise segment and the spanwise segment.

24. The H-shaped heater of claim 19, further comprising: a positive electrical connection on a first end of the first chord-wise segment; and A negative electrical connection is provided on the first end of the first chord-wise segment.

25. The H-shaped heater of claim 19, wherein the span-wise segments have a first width and each of the chord-wise segments has a second width that is half the size of the first width.

Images