US2891136A - Radiant heating device - Google Patents

Description

June 16, 1959 M. NATHANSON RADIANT HEATING DEVICE Filed Oct. 2, 1956 INVENTOR.

MAX NATHAN-Y0 flTTOR/Vlj United States Patent RADIANT HEATING DEVICE Max Nathanson, Montreal, Quebec, Canada Application October 2, 1956, Serial No. 613,496

9 Claims. (Cl. 219-34) The present invention relates generally to heaters, and in particular to an improved infra-red heating device capable of producing a directed bundle or beam of rays suitable for both indoor and outdoor applications.

The principles of infra-red heating are generally known, but the practical applications of this approach to heating is in the developmental stage, with but limited every day use. Many advantages are realized by employing infrared heating which may be attributed, in good measure, to the fact that the rays travel through the air without absorption, yet may be absorbed by objects having appropriate wave lengths of absorption. Thus, by properly selecting the temperature of an infra-red emitter, the emitted rays may be made of wave length to correspond to the wave length of maximum absorption of the human body.

Infra-red heating is feasible and desirable in situations where central heating or conduction heating is not effi cient or impractical. Typical of the numerous applications suited to infra-red heating are extremely high or large rooms, drafty spots, outdoor installations (i.e. stadiums), and infrequently used buildings where it is not eflicient or practical to employ a conventional heating system,

Broadly, it is an object of the present invention to provide an improved heater operating in accordance with the foregoing principles. Specifically, it is within the contemplation of the present invention to provide a device capable of producing infra-red radiation under practical, safe and economical conditions.

Generally, infra-red heating devices are available which embody an infra-red emitter mounted in operative relation to a metal reflector. The emitter is usually in the form of a coil of wire encased within a glass tubular sleeve, the coil being supplied with current from a source of line potential and arranged to operate at a temperature appropriate to emit infra-red rays. The comparatively high operating temperature of the infra-red emitter requires special precautions to avoid excessive heating of the components surrounding the emitter, or seriously curtails the upper operating limit of temperature for the infrared emitter,

In accordance with aspects of the present invention, an improved infra-red heating device is provided which is capable of operating at high temperatures, with more than adequate thermal isolation of the infra-red emitter. Advantageously, high operating temperatures may be tolerated; and the wave length of infra-red emission may be made to correspond to the maximum absorption wave length of the human body. Thus avery significant improvement in the output and efiiciency of the emitter may be realized without creating a safety or fire hazard.

In an illustrative embodiment in accordance with the present invention, a radiant heating device is provided which embodies an infra-red heating assembly including an emitter and a reflector. A wiring compartment is arranged to provide power input to the emitter, the construction of the wiring compartment and the radiant heat- 2,891,136 Patented June 16, 1959 ing assembly being such as to provide an air-circulation passage or opening between the high temperature infrared heating assembly and the remaining components and surrounds of the device.

The above brief description, as well as further objects, features, and advantages, of the present invention will be more fully appreciated by reference to the following detailed description of a presently preferred embodiment, when taken in conjunction with the accompanying drawings, wherein:

Fig. 1 is a front elevational view of a radiant heating device embodying features of the present invention;

Fig. 2 is a fragmentary elevational view, on an enlarged scale, showing the details of the right end of the radiant heating device illustrated in Fig. 1; and,

Fig. 3 is a sectional view taken substantially along the line 33 of Fig. 2 and looking in the direction of the arrows.

Referring now specifically to the drawings, there is shown a radiant heating device which embodies features of the present invention and is designated by the reference numeral 10. The device includes a wiring compartment 12, an infrared emitter or heating element 14, a reflector 16, and a guard 18.

The wiring compartment 12 is rectangular and includes a top wall 20, side walls 22, 24 and end walls 26, 28. The walls cooperate to define an enclosure 30 which receives power input or energization leads 32, 34 which are connected respectively to the opposite end of the infrared emitter 14. The wiring compartment is suspended home support (i.e. ceiling or wall) by a number of hollow hanger rods 36, each of which has a threaded end 36a extending through an opening provided in the top wall 20 of the wiring compartment.

The hanger rod 36 is mounted on the top wall 20 by the following arrangement, which provides a weather-tight mount, particularly suitable for outdoor use. The weather-tight connection 38 embodies a short coupling sleeve 38a which is internally threaded and arranged to extend outwardly from the top wall 20. The coupling sleeve 38a receives the thread end 36a of the hanger rod 36 and is fixed to the top wall 20 by a nipple 38b which is located within the compartment. The nipple 38b is internally threaded and extends upwardly through the top wall 20 and is engaged within the adjacent lower end of the coupling sleeve 380. The lower end of the nipple 38b is flanged, and through a fiat metal washer 380 is arranged to urge a rubber washer 38d against the under surface of the top wall 20. Tightening of the nipple expands the rubber washer 38d to provide a seal about the hole in the top Wall 20. An additional flat metal washer 38c is interposed between the lower end of the coupling sleeve 38a and the top surface of the top wall 20 to serve as a footing for the coupling sleeve. Alterna tive structures for connecting the suspending rods 36 to the compartment are contemplated.

As seen in the detailed showing at the right of Fig. 2, the input leads 32, 34 run from the wiring compartment through the adjacent hollow hanger rod 36 for connection to a source of line potential (not shown).

The side and end walls of the compartment 12 frame an open bottom for the wiring compartment, the location of which is generally designated by the reference numeral 40. As seen best in the detailed showing of Figs. 2 and 3, the location of the open bottom 40 is spaced above the terminal ends 26a, 28a of the end walls 26, 28, which terminal ends have a curvature conforming generally to the curvature of the guard 18. The open bottom 40 is closed by a stepped bottom. wall 42 which includes a main section 42a extending in a first plane, and end-adjacent terminal sections 42b which extend in a second plane spaced below the first plane. The

terminal sections 42b are supported from the main sec tion 42a by the vertically-extending steps 420. The major extent of the open bottom. 40 is in the plane on the main section 42a, except for the short terminal portions corresponding to the terminal sections 42b. To provide a complete enclosure for the wiring compartment, the front and rear side walls 22, 24 of the compartment are provided with depending extensions of a length substantially corresponding to the length of the steps 42c of the bottom wall 42.

The bottom wall 42 is supported on a number of depending U-shaped brackets, one of which has been designated by the reference numeral 44. Each of the brackets is welded or otherwise secured within the wiring enclosure 30. In the illustrative embodiment, the brackets 44 are mounted by securing outwardly bent portions 44a, 44b of the leg sections 44c, 44d of the bracket to the under surface of the top wall 20 of the wiring compart ment 12. The bottom wall 42 is releasably attached to the brackets 44 by threaded studs 45 which are carried on the bight sections 44e of the brackets 44 and extend through appropriate holes in the bottom wall for engagement by wing nuts 46. The illustrated mount for the bottom wall 42 of the wiring compartment 12 allows the bottom wall to be dropped out when access to the interior of the wiring compartment is required. The securement of the bottom wall in place merely involves bringing the wall into the desired position wherein the threaded studs extend through the aligned openings in the bottom wall in position to be engaged by the wing nuts 46.

The reflector 16 embodies a semi-cyclindrical body of appropriate heat-resistant metal having a highly reflective inner surface 16a (i.e. highly polished aluminum) and carries at each of its ends a terminal housing 48, one of which is seen at the right in Fig. 2. The terminal housings 48 are rectangular and adapted to receive opposite terminal end portions of the infra-red emitting or heating element 14. Each of the housings 48 is dependingly supported from the reflector 16 and includes an end plate 50 spaced inwardly from the end of the reflector 16 formed with a keyhole opening for the extension therethrough of the end portion of the heating element, front and rear side walls, 56 and a bottom wall 58. The end of the terminal housing remote from the wall 50 is open but is closed in the final assembly by the end walls 28 assuring positive protection against contact with live wires or parts.

The heating element 14 includes an elongated tube 60 fabricated of pure smelted silica which encloses and protects a special alloy heating wire 62 in the shape of a continuous coil or helix. The wire 62 may be of Nichrome or similar high temperature alloy capable of operating at temperatures of the order of 1800 F., and is in continuous circumferential contact with the inner periphery of the supporting tube 60. The ends of the wire 62 are connected to conductive end caps 64 on the tube 60 which are located respectively within the terminal housings 48. The end caps 64 of the heating element 14 are connected to the input lines 32, 34 by terminal or bus bars 66 which extend through stand-01f insulators 68 and are connected to terminal posts 70 within the stepped portion of the wiring enclosure 30. Although the structure associated with the left end of the heater element 14 is not illustrated, it is the same in all essential detail to that illustarted at the right in Fig. 2. The pure smelted silica tube 60 which supports the heater wire 62 has a triple purpose, to wit: it supports the wire 62 without impediment to the passage of infra-red rays; it protects the wire due to its high resistance to thermal shock, and this property makes the units suitable for outdoor use without being adversely affected by rain, sleet or snow; and finally, it effectively reduces convection losses. Convection losses are reduced in that there is a minimum area contact between the air and the heated wire particularly as compared to the contact which would exist between a bare wire and air. When th hot wire 62 is operated at a temperature of the order of 1800 F., the surface temperature of the tube is of the order of 1500 F.

The radiant heating assembly consisting of the reflector 16 and the emitter 14, which make up the high temperature components of the device, are supported on the drop bottom wall 42 of the wiring compartment 12 by a number of inverted U-shap'ed hangers 72, each of which has its bight section 72a riveted to the undersurface of the bottom wall and has its opposite leg sections 72b, 72c riveted to the opposite edge portions of the reflector, as seen best in Fig. 3.

The guard or protective cage 18 includes a number of longitudinal members 74 which are joined in a curved array by cross bars 76. The curvature of th cage 18, when viewed in end section, substantially corresponds to the curvature of the terminal ends 26a, 28a of the end walls 26, 28. The cage or guard, 18 is mounted on said terminal ends by the provision of one or more offset springy fingers, such as 74a which are received within appropriate openings in the end walls by snap action.

The construction of the device, particularly the manner of mounting the high temperature parts 14, 16, defines a substantial air-circulating space between said high temperature parts and the wiring compartment, specifically between the reflector 16 and the main section 42a of the bottom wall 42. The wiring compartment 12 is close to the reflector only at the end or terminal portions, that is at the regions represented by the terminal sections 42b of the 'bottom wall 42. However, even at these locations, a minimum spacing of the order of inch is maintained in a practical embodiment. By this feature, the temperatitre within the wiring compartment 12 is maintained at a level to permit the employment of standard asbestos covered lead-in wires 32, 34. At terminal portions of the lead-in wires 32, '34 where temperatures may become high, the wires are stripped of their normal asbestos insulation and replaced by porcelain beads, as illustrated at 82 at the right in Fig. 2. The wiring compartment 12 may be completely enclosed and rendered virtually water tight by maintaining appropriate dimensional control between the bottom wall and the opening defined by the several walls of the compartment proper. In practical installations and operating with the emitter at a temperature of 1800' F., the surface temperatures on the wiring compartment 12 are well within the safe limits whereby the heating device may come into direct contact with the wall ceiling or other type of inflammable surface without fear of fire hazard. In typical installations, the surface temperature of the wiring compartment has been found not to exceed F. despite the fact that the only cooling of the unit is achieved by the air which flows Within the substantial gap 80 between the high temperature components and the wiring compartment.

The installation of the present radiant heating device is but a simple matter. It may be accomplished in the field with no difficulty. A typical installation sequence will not be described in detail to facilitate a more thorough understanding of the invention.

Initially the guard 18 is removed by releasing the fingers 74a from the corresponding openings in the end walls 26, 28 of the compartment 12. Upon releasing the wing nuts 46 from the studs 45, the bottom wall 42 of the wiring compartment along with the heating element, 14 and the reflector 16 may be detached from the body proper of the wiring compartment. T hereupon, the body of the wiring compartment may be attached to a supporting surface, for example a ceiling, by the use of the hanger or suspension rods 36. The power supply leads 32, 34 may be introduced through one of the hanger rods 36, or if required through prefabricated knockout holes in the top wall 20 of the wiring compartment.

The power supply leads 32, 34 are connected to the lead sections 32a, 34a by appropriate splices. Lead sections 32a, 34a are supplied with the unit and have stripped ends. The lead sections 32a, 34a carry the porcelain insulating beads 40, as described in conjunction with Fig. 2. When this connection is completed, the bottom wall 42 may be replaced in its supported position by again engaging the wing nuts on the respective studs or bolts. Thereupon, the guard 18 is replaced, which in its supported position cooperates with the reflector 16 and the adjacent portions of the end walls 26, 28 to effectively preclude contact with the infra-red heating tube 14.

Heating devices embodying features of the present invention may be constructed with power ratings of anywhere from 500 to 10,000 watts and of lengths between 20 and 70 inches. A latitude of modification, substitution and changes is intended in the foregoing disclosure, and accordingly it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention. In some instances, certain features of the invention will be used without a corresponding use of other features.

What I claim is:

1. An infra-red heating device comprising a casing including top, side and end walls defining a wire compart ment having an open bottom, said end walls extending to locations beyond said open bottom, a bottom wall adapted to traverse and close said open bottom, means for releasably securing said bottom wall to said casing to seal ofl said wire compartment, a radiant heating assembly extending between said end walls and including a heating element and a reflector, hanger means for suspending said assembly from said bottom wall in spaced relation to said bottom wall, the space between said bottom wall of said casing and said assembly alfording heat isolation between said heating element and said wiring compartment, and a heater guard detachably mounted on said end walls of said casing and cooperating with said reflector and said end walls to provide a protective cage about said heating element.

2. In a radiant heating device, an elongated weatherproof casing having a bottom wall, wiring in said casing for connection to a power supply, an elongated weatherproof radiant heating assembly including a heating element, a reflector in assembled relation with said heating element, terminal housings on said reflector in spaced relation to said bottom wall receiving opposite end portions of said heating element, means mounting said radiant heating assembly on said casing in spaced relation to said bottom wall whereby a substantial air-circulating space is provided between said elongated casing and said radiant heating assembly, said means including hangers carried by said bottom wall and connected to said reflector, and means providing electrical connections between said wiring and said opposite end portions of said heating element at said terminal housings.

3. In an infra-red heating device, an elongated casing including top, side and end walls defining a wiring compartment having an open bottom and adapted to receive wiring for connection to a power supply, a stepped bottom wall for said compartment including a main section extending in a first plane and end-adjacent terminal sections extending in a second plane spaced from said first plane, an elongated radiant heating assembly including a heating element, a reflector in assembled relation with said heating element and terminal housings on said reflector receiving opposite end portions of said heating element, means on said bottom Wall mounting said radiant heating assembly on said casing with said assembly in spaced relation to said main section of said bottom wall whereby an aircirculating space is provided between said elongated casing and said radiant heating assembly substantially throughout the length of said assembly, and means on said terminal sections of said bottom wall for providing electrical con- 6 nections between the wiring in said compartment and said opposite end portions of said heating element.

4. In a radiant heating device, an elongated casing having an open bottom, a bottom wall for said casing including a main section and end-adjacent terminal sections spaced below said main section, an elongated radiant heating assembly including a heating element, a reflector in assembled relation about said heating element and terminal housings on opposite ends of said reflector receiving opposite end portions of said heating element, means mounting said radiant heating assembly on said casing in spaced relation with said main section of said bottom wall whereby an air circulating space is provided between said elongated casing and said radiant heating assembly, the mounting of said radiant heating assembly on said casing bringing said terminal sections of said bottom wall into adjacent relationship with said terminal housings, and means supported in said terminal sections and extending into the adjacent terminal housing for providing electrical connections to said opposite end portions of said heating element.

5. An infra-red heating device comprising a casing including top, side and end walls defining a wire compartment having an open bottom, said end walls extending to locations beyond said open bottom, a drop bottom wall adapted to traverse and close said open bottom, means for releasably securing said bottom wall to said casing to seal olf said wire compartment, a radiant heating assembly extending between said end walls and in cluding a reflector and a heating element supported by said reflector, and hanger means on said bottom wall for suspending said reflector from said bottom wall in spaced relation to said bottom wall, the space between said bottom wall of said casing and said reflector affording heat isolation between said heating element and said wiring compartment.

6. In an infra-red heating device, an elongated casing including walls defining a wiring compartment adapted to receive wiring for connection to a power supply, a stepped bottom wall for said compartment including a main section extending in a first plane and endadjacent terminal sections extending in a second plane spaced from said first plane, an elongated radiant heating assembly including a heating element having opposite terminals, a reflector in assembled relation with said heating element, means on said casing mounting said radiant heating assembly on said casing with said assembly in spaced relation to said main section of said bottom wall whereby an air-circulating space is provided between said casing and said assembly substantially throughout the length of said assembly, and means on said terminal sections of said bottom wall for providing electrical connections between the wiring in said casing and said opposite terminals of said heating element.

7. In a radiant heating device, an elongated casing including a bottom wall having a main section and endadjacent terminal sections spaced below said main section, an elongated radiant heating assembly including a heating element, a reflector in assembled relation about said heating element, terminals on said reflector receiving opposite end portions of said heating element, means mounting said radiant heating assembly on said casing in spaced relation to said casing whereby an air circulating space is provided between said casing and said radiant heating assembly, said radiant heating assembly being mounted on said casing with said terminal sections of said bottom wall in adjacent relationship with said terminals on said reflector, and means supported on said terminal sections and connected to the adjacent one of said terminals for providing electrical connections to said opposite end portions of said heating element.

8. In a radiant heating device an elongated weatherproof casing including top, side and end walls defining a wiring compartment having an open bottom, a bottom wall for said casing including a main section and end adjacent terminal sections, an elongated radiant heating assembly including a .high temperature radiant heating element having an envelope and a heating wire in said envelope with end adjacent terminal sections at each end of said'heating element, and a reflector having a concave cross-section in assembled relation about said heating element, means for mounting said radiant heating assembly on said casing in spaced relation thereto with said reflector spaced from said main section of said bottom Wall and with said heating element extending substantially in the longitudinal center plane of said device, said bottom wall and said reflector defining an air circulating space between said elongated casing and said radiant heating assembly, said air circulating space being of progressively increasing vertical extent in opposite direc tions from said longitudinal center plane to the opposite sides of said casing, and wiring in said wiring compartment connected to said heating element at said terminal sections.

9. In a radiant heating device an elongated weatherproof casing including top, side and end Walls defining a wiring compartment having an open bottom, a bottom wall for said casing including a main section and end adjacent terminal sections, an elongated radiant heating assembly including a high temperature radiant heating element having an envelope and a heating wire in said envelope with end adjacent terminal sections at each end of said heating element, and a reflector having a concave cross-section in assembled relation about said heating element, means for mounting said radiant heating assembly on said casing in spaced relation thereto with said reflector spaced from said main section of said bottom wall and with said heating element extending substantially in the longitudinal center plane of said device, said bottom wall and said reflector defining an air circulating space between said elongated casing and said radiant heating assembly, said air circulating space being of progressively increasing vertical extent in opposite directions from said longitudinal center plane to the opposite sides of said casing, wiring in said wiring compartment adapted to be connected to said heating element at said terminal sections, and insulating means through which said wiring is connected to said terminal sections of said heating element.

References Cited in the file of this patent UNITED STATES PATENTS

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