US1393368A

US1393368A - Radiant reflector

Info

Publication number: US1393368A
Application number: US364769A
Authority: US
Inventors: George J Henry
Original assignee: Individual
Current assignee: Individual
Priority date: 1920-03-10
Filing date: 1920-03-10
Publication date: 1921-10-11
Anticipated expiration: 1938-10-11

Description

G. J. HENRY.

RADIANT REFLECTOR. APPLICATION FILED MAR. 10, 1920.

1,393,3 3, Patent ed Oct. 11, 1921..

IN VEN TOR A TTORNE YS State of UNITED STATES "PATENT OFFICE.

Specification of Letters Patent.

Patented Oct. 11, 1921.

Ap lication fled [arch 10, 1920. Serial 110. 364,789.

To all wkomitmay concern:

Be it known 'that I, G'aoner: J. HENRY, a citizenof the United States, and a resident of the cit and county of San Francisco, alifornia, have invented new and useful Im rovements in Radiant Reflectors, of which t he followin is a specification.

My invention has or its object the formingof a reflector for radiant energy such that a beam reflected on the surface of-the reflector and originating at an energy source substantially, at the focus thereof 'Wlll be reflected outwardly as a diverging beam from the reflector; as distinguished from earlier forms wherein'a beam reflected therefrom convertiges, crossing the axis of the curve of the re ector, or-if of a parabolic form, emanates-asa beam whose ra s are parallel with the axis of the paraboloid'.

My invention is particularly adapted to heaters of the radiant type ln which the beam of radiant ener 'is directed from the reflecting surface, an when the reflected rays'of such a beam strike an object on their path, they are transformed into heat energy thereby heat' the object. I

A further 0 ject of m invention is providing within t e space tween the reflector and the heat unita supplementary reflector of relatively smaller dimensions, which receives the most direct rays emanating from the heat unit andrefleets them to the surface ofthe larger reflector when they; are a ainreflected outward or divergent and c ear of the heat unit. this supplement'ary-reflecting curved sur ace I prevent the concentration of reflected rays'back upon the surface of-therheat unit, and. which have heretofore been accompanied by the early destruction ofthat ortion of the heat unit thus subjected-to this excessive heating.-

Or, the reflector may be formed at its central portionwith. a cusp, or. su plementary reflecting curved surface where y the said direct energy rays'instead of bein reflected back on the ad acent ortiono the heat unit are directed away rom such path.

With-my invention .the reflector, and especially the central portion thereof, is kept o'ooleathan in types heretofore emplofying the, continuous curved or flat surface 0 the reflector with its concavesurface toward the heat unit.

By referring, to the accompanying drawmy invention will be made clear. v

igure l'illustrates my hyperbolic form of reflector having a supplementary reflecting surface of relativelysmaller dimensions at its central portion for diverging the direct rays of the heat unit.

' Fig. 2 shows my su plementary form of reflectormounted at t e center of a minbolic form of reflector and spaced t ere-- from.

Fig. 3 illustrates the path of the radiant energy which has heretofore resulted in the eerlydestru'ction of heat units due to the reflected rays from the-center of the reflec'tor.

Fig. 4 shows the manner in which said rays when reflected are diverted from the surface of the heat unit.

.4, 5,6, which are received upon the surface of the

reflectors

2 and 3. The ray 5 is reflected from the surface of 2 in the di rection of the arrow 8, the angle of-incidence being equal to the angle of reflection. Due to the properties ofthe hyperbola the reflected ray 8 will be divergent, the heat unit 1 being mounted at one of the focii of the said hyperbola. The degree of-divergence ofthe ray'8 is dependent upon the degree of curvature of 2, which again is dependent upon the relative osition of the focii"1 and 9 (Fig. 5). If t e surface 2 be revolvedabout the axis 10,- a hyperboloid (or hyperbjola of revolution) Wlll be formed, and the rays as 8 and 11 from'the entire surface will form; collectively a radiant beam diverging into space as 'it issues from the reflector. These rays will not cross'the axis 10 and therefore a relatively even distribution of the: energy in the space in front of the reflector 2 will be secured .with the least danger. of fire due to the concentration ofrays where they would cross the axis in other forms.

In Fig. 2 the'well known form of parabola ios is shown, in which rays, as 6, striking the surface of 3 from the energy source 1, will issue from the surface of the parabola as indicated by the arrow 12, parallel with the axis 10.

In the preferred form of radiant heaters these reflectors as '2, 3, are relatively small; whereas, the area to be covered by the radiant beam is usually of relatively larger di? mensions, and therefore the parallel beam from the parabolic reflector of Fig. 2 does not cover a sufficient area, whereas the beam emanating from my hyperbolic reflector, (Fig. 1), may, depending upon the curvature of the hyperbola, have any degree of divergence and therefore be made to cover any re uired area.

n Fig. 3 is shown the effect of the rays emanatingfrom the energy source, or heat unit 1, due to their reflection from the relatively flat surface of the back of the reflector 13, and which are returned'upon the heat unit as at 14, thereby raising the temperature of that portion indicated by the black area 15, to a much higher degree than the balance of the unit. This results in the early destruction of the heat unit at or about that portion indicated -by the numeral 15. To overcome this I form the back of the reflector near its center with a cusp, or sup lementary reflecting surface, as shown at ig. 4, which surface may be made integral with, or mounted on, or spaced from the reflector surface 16. Such acusp spaced from the reflector 16 is shown by the numeral 17, and it willbe'seen that the beam of energy emanating from the heat unit 1 will be received upon the surface of the cusp, and directed as indicated by the arrow 18, thus effectually preventing its return upon and destruction of the heat unit 1, and thedistribution of the radiant energy on the reflecting surface is much better.

' At 4 (Fig. 1) is shown the further path of such a ray which first emanates from the heat unit 1, and is then reflected upon the surface 19, until it strikes the surface of the hyperbolic reflector 2, as at the point 20, when it is reflected again, as in the direction '11. A similar result is attained with the parabolic reflector 3, Fig. 2, when provided with my supplementary reflecting surface whereby the ray '7 'is first reflected upon the surface of the cusp 19, impinging upon the reflector 3 at the point 21, and is reflected therefrom as indicated by the ray 22, thus effectually protecting the heat unit from destruction, and providing a radiant divergent reflected beam from those portions of the heat unit, which heretofore were quickly destroyed by the returning energy from the flat surface of the reflector as at 13, Fig. 3.

The hyperbolic curve, which corresponds with the cross section through my preferred formed such that the distance from the point 24 (on the line 9-23) to the point on the'surface of the curve 2, plus the d15- tance.25 '-1 is equalto the distance 24-26 plusthe distance 26--1.

The revolution of the curve 2 about the axis 10 will produce the curve of the surface of the hyperbolic reflector; or, instead of revolving about the axis 10 the rc'flector'may be formed of a plane surface bent into the curve 2. The focus of such a plane surface bent into said curve 2 will then be a line instead of a point, and the heat unit may be suitably elongated; or, in practice the heat unit 1 may be somewhat elongated in the direction at right angles to the figures, and the surface 2 being relatively much larger than the said unit may advantageously be retained as a hyperboloid of revolution.

Moreover, in practical work the heat unit 1 is usually of a "material size instead of a mathematical point, and may be of any well known form, as for example, triangular in cross section in which case a greater percentage of the energy emanating from the said heat unit will be reflected from the surface of the reflector. My invention, however, is directed to the shape of the reflector and the path of the rays received thereon from any heat unit mounted substantially at or about a focal center thereto, and not to a specific form of the heat unit itself.

I claim:

1. A reflector for radiant energy com rising a smooth surface of hyperbolic form, and a heat element located substantially about the focus of the curve surface in combination with a supplementary reflector of cusp form located within the first named rehector and adjacent to the heat element.

2. A. reflector for radiant energy comp'ri'sing a smooth surface of hyperbolic form, and a heat element located substantially about the focus of the curve surface in combinatlon with a supplementary reflector of cusp form located within the irst named reflector and adjacent to the heat element, and spaced therefrom to prevent heat conduction between the reflectors.

3 A reflector for radiant energy consisting of a surface of curved form and a heat element located within said curve in combination with a supplementary reflector of cusp form located within the first named reflector and adjacent to the heat element.

4. A reflector for radiant energy "consisting of a surface of curved form and a heat element located within said curve in combination with a supplementary reflector or cusp form located within the first named reflector and adjacent .to the heat element and spaced therefrom to prevent heat conduction between the reflectors.

5. In an electric heater a heat element and a reflector of curved form positioned to receive radiant energy emanating from said element and t0 reflect the same in a divergent beam of substantially constant intensity throughout the cross section of said beam, in combination with a supplementary reflector of cuspform located within the vfirst named reflector and adjacent to the heat element.

6. In an electric heater, a heat element ment and reflect same as a diverging beam in combination with a supplementary reflector of cusp form located within the first named reflector and adjacent to the heat ele-' ment, and spaced therefrom to prevent heat conduction between the reflectors.

In testimon whereof, I have hereunto set my hand at an Francisco, California.

GEORGE J. HENRY.