Electrical infrared heater

Abstract

Electrical infrared heaters are disclosed. The electrical infrared heater include an emitter configured to radiate infrared rays; and a reflector configured to be placed at a predetermined distance from the emitter, to reflect substantially all of the infrared rays outwardly from the electrical infrared heater.

Description

ELECTRICAL INFRARED HEATERFIELD

[0001] The present disclosure relates to a heating device, in particular to an electrical infrared heater.BACKGROUND

[0002] Typical radiant efficiency of a gas fired infrared tube heater ranges from 40% to 60%. For configurations that apply flue heat recovery, the apparatus described in US Patent No. 10,495,307 has demonstrated the gross radiant efficiency of above 70%. There are existing electrical radiant heaters in the market with a radiant efficiency of 60% to 75%.

[0003] It is desired to provide heaters with improved radiant efficiency.SUMMARY

[0004] In an aspect, there is provided an electrical infrared heater which includes an emitter configured to radiate infrared rays; and a reflector configured to be placed at a predetermined distance from the emitter, to reflect substantially all of the infrared rays outwardly from the electrical infrared heater.

[0005] In any one of the preceding aspects, the emitter can be a medium or short-wave tubular quartz lamp.

[0006] In any one of the preceding aspects, the emitter can comprise a medium wave quartz infrared lamp with a heating element made of carbon fiber filament enclosed in a clear quartz, red pigmented quartz, or coated quartz and filled with halogen gas.

[0007] In any one of the preceding aspects, the center line of the emitter can be at a predetermined distance of 0.70-0.80 inches (18-20mm) in relation to an inner surface of the reflector.

[0008] In any one of the preceding aspects, the emitter can comprise a short wave quartz infrared lamp with a heating element made of coiled tungsten filament enclosed in a clear quartz, red pigmented quartz, or coated quartz and filled with halogen gas.

[0009] In any one of the preceding aspects, the center line of the emitter can be at a predetermined distance of 0.5-0.7 inches (13-18 mm) in relation to an inner surface of the reflector.

[0010] In any one of the preceding aspects, the emitter can comprise a fast response medium wave quartz infrared lamp with a heating element made of coiled tungsten filament enclosed in a clear quartz, red pigmented quartz, or coated quartz and filled with halogen gas.

[0011] In any one of the preceding aspects, the center line of the emitter can be at a predetermined distance of 0.5-0.7 inches (13-18 mm) in relation to an inner surface of the reflector.

[0012] In any one of the preceding aspects, the emitter comprises a medium wave quartz infrared lamp with a heating element made of coiled Ni-Cr or Fe-Cr-Al filament enclosed in a clear quartz, red pigmented quartz, or coated quartz and filled with halogen gas.

[0013] In any one of the preceding aspects, the center line of the emitter can be at a predetermined distance of 0.6-0.8 inches (15-20 mm) in relation to an inner surface of the reflector.

[0014] In any one of the preceding aspects, the emitter can have an outer diameter of 0.38 inches (10mm).

[0015] In any one of the preceding aspects, the reflector can comprise substantially a first portion and a second portion symmetrical to the first portion.

[0016] In any one of the preceding aspects, each of the first portion and the second portion can have a first segment with a length of 0.35 inches (8.9mm) and an angle 125° relative to the symmetric one, a second segment with a length of 0.44 inches (11.2mm) and an angle 158° relative to the previous segment, a third segment with a length of 0.54 inches (13.7 mm) and an angle 158° relative to the previous segment, a fourth segment with a length of 0.66 inches (16.8mm) and an angle 158° relative to the previous segment, a fifth segment with a length of 1.58 inches (40.1mm) and an angle 158° relative to the previous segment, and a distance of about 5 inches between two ends of the fifth segment of the first portion and the second portion.

[0017] In any one of the preceding aspects, the reflector can be made of aluminum, polished aluminum, aluminized steel and polished stainless steel.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Reference will now be made, by way of example, to the accompanying drawings in which:

[0019] FIG. 1 is a perspective view of electrical infrared heaters according to example embodiments of the invention;

[0020] FIG. 2 is a perspective view of one of the electrical infrared heaters of FIG. 1;

[0021] FIG. 3 is an exploded perspective view of the electrical infrared heater of FIG. 2;

[0022] FIG. 4 is a diagram illustrating example dimensions of the reflector and emitter in FIG. 3;

[0023] FIG. 5 is a diagram illustrating a three-sided reflector for reflecting infrared rays emitted from an emitter;

[0024] FIG. 6 is a diagram illustrating an example reflector for reflecting infrared rays emitted from an emitter;

[0025] FIG. 7 is a diagram illustrating various possible locations of the emitter in relation to the reflector;

[0026] FIGs. 8 and 9 are diagrams illustrating a first location of the emitter in relation to the reflector;

[0027] FIGs. 10(a)- 10(i) are diagrams illustrating the reflected infrared rays from different segments of the reflector when the emitter is placed at different locations relative to the reflector;

[0028] FIGs. ll(a)-ll(c) are diagrams illustrating diffuse and specular reflection of incoming infrared rays;

[0029] FIG. 12 is a diagram illustrating example reflected ray geometry of the first segment of the reflector;

[0030] FIG. 13 is a diagram illustrating example mixed reflection rays; and

[0031] FIG. 14 is a diagram illustrating radiant efficiency of the electrical infrared heater of FIG. 2.

[0032] Similar reference numerals may have been used in different figures to denote similar components.DESCRIPTION OF EXAMPLE EMBODIMENTS

[0033] Infrared heating can be an economical technology for heating large spaces when frequent air changes are required.

[0034] FIGs. 1-3 illustrate examples of an electrical infrared heater 100, and sets of electrical infrared heaters 100(a)-100(f) of the present disclosure. The electrical infrared heater 100 described in this disclosure may also be an electrical heater radiating thermal rays. In this case, thermal rays may include infrared rays, and the visible-light rays.

[0035] In the example of FIG. 1, an electrical infrared heater 100 may include a set of a single electrical infrared heater 100 (a), a set of two electrical infrared heaters 100 (b) and 100(c), or a set of three electrical infrared heaters 100 (d), 100(e), and 100(f). Each of electrical infrared heaters 100 (a)-100(f) is the same as electrical infrared heater 100, as illustrated in FIG. 2.

[0036] As illustrated in detail in FIG. 3, the electrical infrared heater 100 includes an emitter 102, and a reflector 104. The heater 100 may also include a cover 106 for securely receiving the reflector 104. The heater 100 may also include a pair of emitter retainers 108a and 108b configured to be securely mounted in the cover 106. Each of the emitter retainers 108a and 108b is configured to receive an end of the emitter 102, such as by a first bore 109a to receive a first end 102a of the emitter 102a, a second bore 109b to receive a second end 102b of the emitter 102, so as to securely retain the emitter 102 at a predetermined position. The positions of the bores 109a and 109b determines the relative position of the emitter 102 and the reflector 104 when the emitter 102 are mounted to the emitter retainers 108a and 108b, and when the reflector 104 is mounted to the cover 106.

[0037] The heater 100 may also include a pair of side covers 110a and 110b configured to be mounted at the two ends of the cover 106, for covering the emitter retainers 108a and 108b. One of the side covers 110a and 110b, such as 108b, may include an opening 111 for allowing one end of the emitter 102, such as the second end 102b, to connect the emitter 102 to an electrical power.

[0038] In some examples, the cover 106 may include a plurality of slots for allowing warm air to escape the enclosure through the outer surface 104b of the reflector 104. In some examples, the cover 106 may have no slot at all. The heater 100 may also include one or more racks, or strings on the cover 106 for mounting the heater 100 on a wall or a ceiling (not illustrated in the drawings).

[0039] The emitter 102, or a heat generating source such as a tubular quartz lamp, is configured to radiate infrared rays. In some examples, the emitter 102 may be an electrical infrared emitter which generates infrared rays using heat produced by electric current flowing in a high-resistance filament (heating element) to provide heat to the surrounding environment. Most of the energy is transmitted by radiation in the form of infrared rays.

[0040] The emitter 102 may be a short or medium wave tubular quartz lamp and filled with halogen gas.

[0041] The medium wave quartz lamps having a heating element (filament) temperature lower relative to short wave quartz lamps, resulting in their infrared spectrum peak being shifted away from the visible light radiation. In addition, to minimize the glare of the emitter 102, the quartz may be pigmented. The pigmented quartz absorbs a portion of the visible light and emit its energy in a longer wavelength.

[0042] In some examples, the emitter 102 may comprise a clear quartz, red pigmented quartz, or coated quartz.

[0043] The emitter 102 may be configured to be placed at a predetermined distance from the inner surface 104a of the reflector 104. The outer surface 10b of the reflector 104 is opposite to inner surface 104a. The inner surface 104a faces the emitter 102. The reflector 104 is configured to reflect substantially all of the infrared rays from the emitter 102 in direction outwardly from the electrical heater100. In some examples, the reflector 104 may be made of sheet aluminum with a thickness of 0.024 inch (0.609 mm), or sheet steel or coated Steel with a thickness of 0.0152 inch (0.386 mm).

[0044] In some examples, the emitter 102 may include short wave quartz infrared lamps with coiled tungsten filament enclosed in a quartz glass and filled with halogen gas. In this case, the emitter 102 may be positioned relative to the reflector 104 at 0.5-0.7 inches (13-18 mm).

[0045] In some examples, the emitter 102 may include fast response medium wave quartz infrared lamps with coiled tungsten filament enclosed in a quartz glass and filled with halogen gas. In this case, the emitter 102 may be positioned relative to the reflector 104 at 0.5-0.7 inches (13-18 mm).

[0046] In some examples, the emitter 102 may include medium wave quartz infrared lamps with coiled Ni-Cr or Fe-Cr-Al filament enclosed in a quartz glass and filled with halogen gas. In this case, the emitter 102 may be positioned relative to the reflector 104 at 0.6-0.8 inches (13-18 mm).

[0047] In some examples, the emitter 102 may include medium wave quartz infrared lamps with carbon fiber filament enclosed in a quartz glass and filled with halogen gas. In this case, the emitter 102 may be positioned relative to the reflector 104 at about 0.7 - 0.8 inches (18-20mm).

[0048] In the example of FIG. 4, the reflector 104 has substantially two symmetrical first portion 104(i) and second portion 104(H). Each of the first and second portions 104(i) and 104(H) includes five segments 104a, 104b, 104c, 104d, and 104e. Each of the segments 104a, 104b, 104c, 104d, and 104e has an inner surface. The inner surfaces of the segments 104a, 104b, 104c, 104d, and 104e of both the first and second portions 104(i) and 104(ii) collectively form the inner surface 104a.

[0049] In the example of FIG. 4, the length of the segment 104a is 0.35 inches (8.9mm), the length of the segment 104b is 0.44 inches (11.2mm), the length of the segment 104c is 0.54 inches (13.7 mm), the length of the segment 104d is 0.66 inches (16.8mm), and the length of the segment 104e is 1.58 inches (40.1mm). In FIG. 4, the distance between the two ends of segments 104e at the first portion 104(i) and section portion 104(H) is about 5 inches (127mm).

[0050] In the example of FIG. 4, the angle Al formed between the inner surfaces of segments 104d and 104e is 158°, the angle A2 formed between the inner surfaces of segments 104d and 104c is 158°, the angle A3 formed between the inner surfaces of segments 104c and 104b is 158°, the angle A4 formed between the inner surfaces of segments 104b and 104a is 158°, the angle A5 formed between the outer surfaces of segments 104a and 104a is 125°. The height of the reflector 104 is 1.99 inches.

[0051] In the example of FIG. 4, the distance between the center of the emitter 102 and joint point J of the inner surface of two segments 104a is about 0.8 inch (20mm). The outer diameter (OD) of the emitter 102 may be 0.38 inches (10mm).

[0052] As will be described in detail below, the configuration of the reflector 104 in FIG. 4 directs substantially all the infrared rays, including infrared rays, out to the heater 100 and to reflect substantially all of the radiant energy from the emitter 102 in a focused, outward, direction and thus improves the radiant efficiency of the heater 100. In the heater 100, substantially all the infrared rays emitted from the emitter 102 are reflected from the reflector 104 and leaving the space between the emitter 102 and reflector 104 without returning to the emitter 102.

[0053] The heater 100 with the emitter 102 and the reflector 104 configured in the example of FIG. 4 has an improved radiant efficiency above 90%. The radiant efficiency is measured using a radiometric method. The radiant output is measured by means of a standardized and calibrated Ulbricht sphere of constant referencetemperature with a radiometric sensor at different points on a grid of the measuring plane beyond the heater 100.

[0054] Reflector shape has the primary effect on the radiant efficiency of a radiant heater. FIG. 5 illustrates the infrared ray paths in a three-sided reflector 190. The three-sided reflector 190 may be used in a gas fired radiant heater. As illustrated in FIG. 5, the heat rays 192 are reflected to the top surface of the emitter 194, and thus kept between the top of the emitter 102 and reflector 194 and are not reflected outside the reflector 192. Therefore, reflector 190 has a relatively low radiant efficiency.

[0055] The air temperature between the emitter and reflector 190 increases, due to contact with hotter surfaces, resulting in the increasing the convective heat associated with hot air escaping this cavity, and in the increase of the cover 106 temperature contributing to the reduction of radiant efficiency of the heater 100.

[0056] The cover 106 emits convective and radiative heat that escapes the heater 100, reducing the amount of radiant heat directed outwardly from the heater 100 to the floor.

[0057] In contrast, the reflector 104 in FIG. 4, and as illustrated in FIG. 6, directs substantially infrared rays leaving the emitter 102 to radiate the heat into the environment outside the reflector 104. The reflector 104 may deliver up to 1.5 times the infrared energy relative to the three-sided reflector 190, and thus provides a relatively high radiant efficiency. The reflector 104 may be used in heater 100, which may be a gas fired infrared heater.

[0058] As the emitter 102 may have different sizes, the distance between the emitter 102 and the reflector 106 may also affect the radiant efficiency of the heater 100. FIG. 7 illustrates examples of placing the emitter 102 from the center or center line of the emitter 102 to the joint point J of first segment 104a of thefirst portion 104(i) and the second portion 104(H) at a distance of 1.05 inches (27mm), 0.7 inches (18mm), or 0.5 inches (13 mm). The center of the emitter 102 in the examples of FIG. 4 may be the center c or the center line of the emitter 102 corresponding to the central axis A-A in FIG. 3.

[0059] FIGs. 8 and 9 illustrate an example wherein the emitter 102 is placed from the center of the emitter 102 to the joint point J of first segment 104a of the first portion 104(i) and the second portion 104(H) at a distance of 1.05 inches (27mm).

[0060] In the example of FIG. 8, only half of the infrared rays emitted from the emitter 102 to the second portion of the reflector 104(ii) are illustrated. In the example of FIG. 8, only half of the infrared rays emitted from the emitter 102 to the second portion of the reflector 104(H), and infrared rays reflected by the second portion of the reflector 104(ii) are illustrated. Due to the symmetricity between the first portion and the second portion of the reflector 104(i), the first portion of the reflector 104(i) has symmetrical emission and reflection of the infrared rays as the second portion of the reflector 104(H) in FIGs. 8 and 9. In the example of FIG. 9, all the infrared rays leaving the emitter 102 undergo a specular reflection on the surface of reflector 104.

[0061] FIGs. 10(a)-10(i) illustrate specular infrared ray distribution when the center of the emitter 102 to the joint point J of first segment 104a of the first portion 104(i) and the second portion 104(H) is at a distance of 1.05 inches (27mm), 0.7 inches (18mm), and 0.5 inches (13mm).

[0062] In FIGs. 10(a)-10(c), the distance between the center of the emitter 102 and the joint point J of first segment 104a of the first portion 104(i) and the second portion 104(H) is 1.05 inches (27mm). In FIG. 10(a), when the center of the emitter 102 to the joint point J of first segment 104a of the first portion 104(i) and the second portion 104(H) is at a distance of 1.05 inches (27mm), the first segment104a reflects all infrared rays to the fifth segment 104e. In FIG. 10(b), the second segment 104b reflects all infrared rays outwardly away from the reflector 104. In FIG. 10(c), the segments 104c, 104d, and 104e reflect all infrared rays outwardly away from the reflector 104.

[0063] In FIGs. 10(d)-10(f), the distance between the center of the emitter 102 and the joint point J of first segment 104a of the first portion 104(i) and the second portion 104(H) is 0.7 inches (18mm). In FIG. 10(d), the infrared rays emitted from the emitter 102 to the first segment 104a are reflected to the fourth segment 104d and fifth segment 104e. In FIG. 10(e), the second segment 104b reflects a portion of the infrared rays outwardly away from the reflector 104, and a portion of the infrared rays to the fifth segment 104e. In FIG. 10(f), the segments 104c, 104d, and 104e reflect all infrared rays outwardly away from the reflector 104.

[0064] In FIGs. 10(g)-10(i), the distance between the center of the emitter 102 and the joint point J of first segment 104a of the first portion 104(i) and the second portion 104(H) is 0.5 inches (13mm). In FIG. 10(g), the infrared rays emitted from the emitter 102 to the first segment 104a are reflected to the fourth segment 104d and fifth segment 104e, with more infrared rays reflected to the fourth segment 104d compared with Figure 10(d). In FIG. 10(h), the second segment 104b reflects a portion of the infrared rays outwardly away from the reflector 104, and a portion of the infrared rays to the fifth segment 104e, with more infrared rays reflected to the fifth segment 104e compared with Figure 10(d). In FIG. 10(i), the segments 104c, 104d, and 104e reflects all infrared rays outwardly away from the reflector 104.

[0065] FIGs. ll(a)-ll(c) illustrate diffuse and specular reflections of infrared rays. The infrared rays emitted from the emitter 102 which fall on the inner surface

[0066] FIG. 11 (a) is an example of a specular reflection. In FIG. 11(a), the incident infrared ray 1202 at an angle 91, and is reflected at the inner surface 104a as reflected ray 1204 at one angle 02, and 01= 02.

[0067] FIG. 11 (b) is an example of diffuse reflections. In FIG. 11(b), the incident ray 1202 at an angle 01 is reflected as rays 1205 at various angles in the hemisphere surrounding the surface 104a, following lambert's Cosine Law.

[0068] Typically, in electrical infrared heater reflector 104, the specular and diffuse reflections of the infrared ray 1202 occur as a mixed reflection. In the example of FIG. 11(c), incident ray 1202 at an angle 01 is reflected as rays 1204 and diffused as rays 1205. The reflected ray's magnitude indicates the heat flux in the particular directions.

[0069] The construction material of reflector 104 may affect the specular and diffused reflections. The reflector 104 of the heater 100 may be made of aluminum, and exhibit a mixture of specular and diffused reflections. The reflector 104 of the heater 100 may also be made of polished aluminum, and in this case, the inner surface 104a has enhanced specular reflection and improves the radiant efficiency of the heater 100 for short and medium-wave light, such as infrared rays.

[0070] The Phong Reflection Model can be used to characterize the mixed reflection. In the example of FIG. 12, the incident ray geometry of the first segment 104a of the reflector 104 is illustrated. The incident ray 1302 from the center of the emitter 102 to the edge of the first segment 104a of the reflector 104 has an incident angle of 28°. The angle between the specular reflection 1306 of the incident ray 1302 and the tangent 1308 to the outer diameter of the emitter 102 is about 41°.

[0071] In the case of a mixed reflection, the reflected rays are not returned into the emitter 102 when the mixed reflection rays 1306 lay inside apredetermined angle, such as 41°. The reflector 104 configured in the example of FIG. 4 causes the mixed reflection rays by the first segment 104a stay inside a predetermined angle, such as 41°, and no infrared ray is reflected back to the emitter 102, and the reflector 104 direct substantially all the infrared rays outwardly from the heater 100 to the surrounding environment.

[0072] In terms of the specular reflection of the rays leaving the emitter 102, the maximum radiant efficiency will be provided for the heater 100 if all the rays leaving the heater 100 have been reflected from the corresponding segment.

[0073] FIG. 13 illustrates an example of mixed reflection rays modeled using the Phong Reflection Model. The Phong Reflection Model with a factor 8 may characterize the amount of mixed reflection in FIG. 13. In other words, the amount of specular reflection of the first segment 104a of the reflector 104 has a factor of 8 in Phong Reflection Model, namely, I<p = Io Cos (<p) / K8, where:I<p is the reflected ray magnitude of heat flux in <p angle direction.Io is the reflected ray magnitude of heat flux in specular reflection angle direction, and<p is angle of a reflected ray from the specular reflection direction.The factor "8" in the Phong Reflection Model characterizes the mixed reflection of a medium wave carbon filament lamp and polished aluminum reflector material.

[0074] The radiant performance test may use a radiometric method. The radiant output is measured by means of a standardized and calibrated Ulbricht sphere of constant reference temperature with a radiometric sensor at different points on a grid of the measuring plane beyond the heater 100.

[0075] FIG. 14 illustrates radiant efficiency measurement results of the electrical infrared heater 100, when the emitter 102, calculated from the center of the emitter 102 to the joint point J of first segment 104a of the first portion 104(i) and the second portion 104(H) of the reflector 104, is at various distances from 0.5 inches (13mm) to 1.05 inches (27mm). In the example of FIG. 14, the radiant efficiency of the heater 100 in the distances from 0.5 inches (13mm) to 1.05 inches (27mm) are about 80%, and the maximal radiant efficiency of the electrical infrared heater 100 is above 90% when the distance of the center of the emitter 102 and the joint point J of first segment 104a of the first portion 104(i) and the second portion 104(H) is about 0.7-0.8 inches (18-20mm). Therefore, in this example, the optimal location for the emitter 102 to provide the maximum efficiency is when the distance of the center of the emitter 102 and the joint point J of first segment 104a of the first portion 104(i) and the second portion 104(H) is about 0.7-0.8 inches (18-20mm).

[0076] The power supply of the heater 100 may have a voltage of 120V, 208V, 230V, 240V, 277V, 400V, 480V, 575, 600V, and the heater 100 may output a power of 1,800 W-30,000 W.

[0077] Certain adaptations and modifications of the described embodiments can be made. Therefore, the above discussed embodiments are considered to be illustrative and not restrictive.

Claims

WHAT IS CLAIMED IS:

1. An electrical infrared heater, comprising: an emitter configured to radiate infrared rays; and a reflector configured to be placed at a predetermined distance from the emitter, to reflect substantially all of the infrared rays outwardly from the electrical infrared heater.

2. The electrical infrared heater of claim 1, wherein the emitter is a medium or short wave lamp.

3. The electrical infrared heater of claim 1, wherein the emitter comprises a medium-wave tubular quartz lamp with a heating element made of carbon fiber filament enclosed in a clear quartz, red pigmented quartz, or coated quartz and filled with halogen gas.

4. The electrical infrared heater of claim 3, wherein the emitter is at a predetermined distance of 0.70-0.80 inches (18-20mm) in relation to an inner surface of the reflector.

5. The electrical infrared heater of claim 1, wherein the emitter comprises a short wave tubular quartz lamp with a heating element made of coiled tungsten filament enclosed in a clear quartz, red pigmented quartz, or coated quartz and filled with halogen gas.

6. The electrical infrared heater of claim 5, wherein the center line of the emitter is at a predetermined distance of 0.5-0.7 inches (13-18 mm) in relation to an inner surface of the reflector.

7. The electrical infrared heater of claim 1, wherein the emitter comprises a fast response medium wave tubular quartz infrared lamp with a heating element made of coiled tungsten filament enclosed in a clear quartz, red pigmented quartz, or coated quartz and filled with halogen gas.

8. The electrical infrared heater of claim 7, wherein the emitter is at a predetermined distance of 0.5-0.7 inches (13-18 mm) in relation to an inner surface of the reflector.

9. The electrical infrared heater of claim 1, wherein the emitter comprises a heating element made of medium wave quartz infrared lamp with a coiled Ni- Cr or Fe-Cr-Al filament enclosed in a clear quartz, red pigmented quartz, or coated quartz and filled with halogen gas.

10. The electrical infrared heater of claim 9, wherein the emitter is at a predetermined distance of 0.6-0.8 inches (15-20 mm) in relation to an inner surface of the reflector.

11. The electrical infrared heater of claim 3, wherein the emitter has an outer diameter of 0.38 inches (10mm).

12. The electrical infrared heater of claim 1, wherein the reflector comprises substantially a first portion and a second portion symmetrical to the first portion.

13. The electrical infrared heater of claim 12, wherein each of the first portion and the second portion has a first segment with a length of 0.35 inches (8.9mm) and a first angle of 125° between the first segment of the first portion and the second portion, a second segment with a length of 0.44 inches (11.2mm) and a second angle 158° relative to the first segment, a third segment with a length of 0.54 inches (13.7 mm) and a third angle of 158° relative to the second segment, a fourth segment with a length of 0.66 inches (16.8mm) and a fourth angle of 158° relative to the third segment, a fifth segment with a length of 1.58 inches (40.1mm) and a fifth angle of 158° relative to the fourth segment, and a distance of about 5 inches (127 mm) between two ends of the fifth segment of the first portion and the second portion.

14. The electrical infrared heater of claim 1, wherein the reflector is made of aluminum, polished aluminum, aluminized steel, or stainless steel.

15. The electrical infrared heater of claim 1, further comprising a cover for securely receiving the reflector.

16. The electrical infrared heater of claim 15, further comprising a pair of emitter retainers configured to be securely mounted in the cover, and to securely retain the emitter at a predetermined position.

17. The electrical infrared heater of claim 15, further comprising a pair of side covers configured to be mounted at two ends of the cover.

18. The electrical infrared heater of claim 15, wherein the cover comprises a plurality of slots for emitting infrared rays from an outer surface of the reflector.

19. The electrical heater of claim 13, wherein the first segment has a factor of 8 in Phong Reflection Model for characterizing a mixed reflection of a mediumwave infrared lamp with a heating element made of carbon filament lamp and polished aluminum reflector material.

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