US3179789A - Radiant energy generating and distributing apparatus - Google Patents

Description

April 1965 J. A. GIALANELLA 3,179,789

RADIANT ENERGY GENERATING AND DISTRIBUTING APPARATUS Original Filed Feb. 8. 1960 INVENTOR r/aser-w fl- G'MAAA/HLA? ATTORNEY United States Patent 3,179,789 RADHANT ENERGY GENERATING AND DESTRHBUTKNG APPARATUS Joseph A. Gialanelia, 28 Cypress Ave, North (Ialdweil, NJ. Continuation of application Ser. No. 7,3ti7, Feb. 8, 1950. This application Aug. 26, 1963, Ser. No. 365930 2 Claims. (Cl. 219-349) The present invention pertains to improvements in radiant energy generating and distributing apparatus. This application is a continuation of my copending United States application Ser. No. 7,307, filed February 8, 1960.

The use of radiant energy in a wide range of modern processes, typically heating and drying by means of infrared rays, has been hampered in many cases by such disadvantages as relatively low efiiciency of the energy generator in the transfer of energy to a target area or operating zone, difliculty of obtaining uniform heat application, high cost, and lack of ready adaptability to special requirements.

With a view to eliminating these and related prior ditficulties, one object of the present invention resides in the provision of means for producing radiant energy at maximum efiiciency in selected spectral zones such as the infrared, though not limited thereto.

Another object is to provide apparatus of the above type which may be simply and readily manufactured at low cost.

A further object resides in the provision of apparatus of the above type including an exterior main reflector cooperative with the energy source, an uncoated segmental zone of the tubular envelope being directed toward the reflector.

Another object is to provide a device of the above nature in which the control coatings may have a high absorptive characteristic, or a high absorptive coating and a high reflective coating superimposed thereon.

A further object is to provide heating apparatus in which control coatings may be selectively applied both to the source envelope and the main reflector, to attain any desired distribution or concentration of the generated radiation.

Other objects and advantages of the invention will become evident during the course of the following description in connection with the accompanying drawings, in which FEGURE l is a perspective view of a preferred form of generating unit;

FIGURE 2 is a front view of the generator tube and main reflector assembly;

FIGURE 3 is a typical cross section illustrating the relation of the coated generator tube to the main reflector; and

FEGURE 4 is an enlarged diagrammatic cross section of a typical generator envelope illustrating the use of a segmental coating of high absorptive value backed by a coating of high reflectivity.

In the use of elongated generators for radiant energy, such as infrared, it is customary to employ a concave redoctor to gather and direct the generated rays to the desired zone of application. However, the reflector obviously can control and direct only such rays as fall upon its directing surface, while the primary energy source or filament emits rays in all directions. Asa result, with the usual tubular generator a large proportion of the rays emitted from the convex side of the tube facing outward never reach the reflector, but instead merely escape divergently and are lost from the operating zone. It has been found that the capture of the divergent rays and thier retention within the useful process region will greatly improve operational efiiciency of the apparatus.

Referring now to FIGURE 1, the numeral 15 denotes a tubular sheath or envelope, preferably of fused silica opaque to light. Silica opaque to light is preferred at the present time because of its lower cost compared to transparent quartz. The word opaque as customarily applied to this material refers to its milky appearance in contrast to clear quartz or the like, but in fact it possesses a high degree of transparency for infrared rays in the range up to 4 microns. Enclosed within the envelope 15 is a filament to of high resistance wire, wound in an elongated helix and provided with terminal electrodes It? extending through and supported by end caps 18. A substantially semi-cylindrical zone of the tube 15 is covered by a coating 19 (FIG. 3) or by coatings 21 and 22 (FIG. 4) which in the instant embodiment extends throughout the active length of the tube.

Under normal operating conditions, the generator unit is mounted in an elongated trough-like reflector 20, FIG- URES 2 and 3, the terminal electrodes being held in receptacles 13 of any suitable type as for instance spring loaded connectors, permitting insertion and removal of the generator unit through the end of reflector assembly.

, Referring to FIGURE 3, it will be noted that the tube 15 is mounted closely adjacent to the inner curve of the reflector, and that the side of the tube carrying the coating 19 is orientated outward, that is in the direction away from the reflector 26.

The coating 19 may be of any highly absorptive mate rial, by forming it of a black body material as carbon, molybdenum disulfide, aluminum oxide, etc. As an alternative, a composite coating may be used consisting of an inner absorptive layer 21 on which is superimposed a reflective layer 22 as shown in FIGURE 4. It will be understood that FIGURE 4 is diagrammatic in crosssection in the sense that for purposes of clarity the thickness of the coatings has necessarily been exaggerated.

In the case of the absorptive coating, improved results are attained by reason of the high black body emissivity characteristic of the chosen material. Here again the arcuate coating intercepts all direct rays through the front of the tube and absorbs the greatest part of them, raising its surface to a relatively high temperature. Since all such surfaces radiate in proportion to their emissivity and their absolute temperature, the coating surface emits a large proportion of its absorbed heat inwardly and outwardly from the inner and outer surfaces of the coating respectively, again conserving radiation and agumenting the total radiation by fact of the black body radiation from increased surface area.

In the arrangement shown in FIGURE 4 the inner absorptive layer 21 acts in the same manner as just described, while the outer reflecting layer 22 receives any heat tending to emanate from the outer surface of the layer and returns the major portion of it to the latter for reabsorption, thus preventing undue loss from convection and conduction, with the result that high temperatures and consequent improved operative efiiciencies are obtained.

While in practice the choice among the two arrangements decribed is made in accordance with various factors of intended use such as area of application, spacing of the generating apparatus from the work, etc., it will be noted that all operate in the same basic control manner to conserve radiant energy and increase the intensity and efficiency of its generated output.

With regard to the envelope 15 in all examples, the desired surface portion intended to receive an absorptive coating may be etched, thus producing a roughened inner surface of the applied coating with consequent maximum absorptive and radiating characteristics.

As previously mentioned, the opaque fused silica envelope 15 has the advantage of high transparency in the desired spectral region. Other advantages are strength, the

ability to withstand high temperature, and low cost in comparison to materials such as clear quartz. This low cost, coupled with the fact that the envelope 15 is a simple tube of homogeneous structure, obviously promotes economical manufacture. Other factors of economy are elimination of reflectors and the like Within the tube, and the ease of applying the requisite control coatings to the outer tube surface.

The foregoing description or the invention has been directed mainly to a typical field of advantageous application, namely that of infra-red, but it will be obvious that its basic structures and mode of operation can similarly be employed in connection with other visible and invisible wavelength ranges. Thus when required, gaseous discharge may be substituted for heated filaments, various pigments may be applied to the interstices between sectional coatings of selected forms, and similar detail measures taken to meet particular conditions. In other Words, while the invention has been set forth in preferred form, it is not limited to the precise examples illustrated, as various modifications may be made without departing from the scope of the appended claims.

What is claimed is:

1. In an apparatus for generating and distributing radiant energy, in combination, an elongated source of infrared rays, a tubular envelope enclosing said source and transparent to said rays, an elongated main reflector directed toward said source to receive radiant rays from said source and re-direct said rays in a path in which said source is located, a relatively highly absorptive coating means on an outwardly directed arcuate portion of said envelope presenting an arcuate interior surface facing said reflector to increase the radiant surface of said apparatus and to cooperate with said main reflector in increasing the temperature of said source and envelope as Well as to provide maximum temperature of said coating to thereby minimize the development of convection heat and augment the infrared radiant energy produced by said apparatus.

2. Apparatus as set forth in claim 1 and including a reflective coating superimposed on the exterior outwardly directed surface of said absorptive coating.

References Cited by the Examiner UNITED STATES PATENTS 606,792 7/98 Quida's 219-342 1,110,532 9/14 Byce 338218 X 1,686,865 10/28 Klotz 219349 1,822,076 9/31 Bauersfeld et a].

1,954,128 4/34 Heyroth et al 219461 2,152,934 4/39 Trent 219-540 2,658,984 11/53 Mohn 219354 3,015,711 1/62 Bridwell 2l9531 FOREIGN PATENTS 160,486 3/21 reat Britain.

382,099 9/23 Germany.

445,532 4/36 Great Britain.

519,137 3/40 Great Britain.

RICHARD M. WOOD, Primary Examiner.

Claims (1)

1. IN AN APPARATUS FOR GENERATING AND DISTRIBUTING RADIANT ENERGY, IN COMBINATION, AN ELONGATED SOURCE OF INFRARED RAYS, A TUBULAR ENVELOPE ENCLOSING SAID SOURCE AND TRANSPARENT TO SAID RAYS, AN ELONGATED MAIN REFLECTOR DIRECTED TOWARD SAID SOURCE TO RECEIVE RADIANT RAYS FROM SAID SOURCE AND RE-DIRECT SAID RAYS IN A PATH IN WHICH SAID SOURCE IS LOCATED, A RELATIVELY HIGHLY ABSORPTIVE COATING MEANS ON AN OUTWARDLY DIRECTED ARCUATE PORTION OF SAID ENVELOPE PRESENTING AN ARCUATE INTERIOR SURFACE FACING SAID REFLECTOR TO INCREASE THE RADIANT SURFACE OF SAID APPARATUS AND TO COOPERATE WITH SAID MAIN REFLECTOR IN INCREASING THE TEMPERATURE OF SAID SOURCE AND ENVELOPE AS WELL AS TO PROVIDE MAXIMUM TEMPERATURE OF SAID COATING TO THEREBY MINIMIZE THE DEVELOPMENT OF CONVECTION HEAT AND AUGMENT THE INFRARED RADIANT ENERGY PRODUCED BY SAID APPARATUS.

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