US2381345A - Grill - Google Patents

Description

y@ /jj o' o I o 7, 1945',v A. l.. GREENLAW y I y 2,381,345

- GRILL Filed June'5, 1942 a' 'Mns/Nnrzmsr ma Jffz [www Patented Aeg. 7, 19.45

UNIT-ED. STATES RATENT OFFl'Cl.

.fGRmL vAlfred LfG'reenlaW, New-BritainyGonm t n Application dunes, 1942, serial No. .445,836

. Q3 Claims. ("Cl. 918-40) y When ,introducing airinto a room, whetherxfor heatingcooling or ventilation, .it is highly desirable. that this. be accomplished .in ar manner whichl will not impart xa sensation of draft :to

persons Ain `the room. -Heretofore .attempts r to avoid sensation of draft 'have' commonly been based 4.on the idea of reducing fthe velocity of ther air entering .the room ito .a low 4value,` and lto .this end the entering Aair column has I been enlarged in `.cross sectionf'asby the yuseofiducts flaring outwardly; toward fthe interior of the room,

in .the desired.,proportionsfbetween' the ducts. Y

The present invention'has for lanobje'ct to produce the same'freedomfrom .draftslbu't loy'a 'different method of control yw'hichihas"certain spreads outwardly. close to .thesurfacel of the'wall in which' the outlet opening is placedanolit diffuses therefrom into the remainderof thev room.

One advantage-of this .zmethod is that it're- .quires no long/tapering air lpassages. Thus the 4grill mayjbe used where there rgisnno roomffor such'longair passages. For example, it is Lpossible to set the grill substantially flush withvthe wall,v even whenthere islittle space back-of-athe Wall. to. the v.end of the distribution.ductgthrough .which thel air is suppliedk to theroom'.

A vfurther advantage ,is that. it .makes possibl j theiuse .of a grill.. having exposed face' portions of substantialwidth, Which,.in turn, permits the grill `tobe made withmuchgreater mechanical strength. ,It is thus practicable 'to gplace sucha grill4 in the oor Where it may beLwalked'onand `may support substantialweight, without iinjury.

Where no substantial .weight `is required to'rbe supported by theA grill, it may be made of vvery light construction which can be made very cheaply and with a .small amount of material.-

The presentfapplicaton .is va continuation lin ypart of my application Serial No. 279,443 'filed June f16, 1939, for Grills and containscertain` subvject matter `.divided '..out therefrom. The-more general aspects of thexinventionhare contained 1942, now Patent. No. 2,341,439, February? f8, 1944,

.also as a continuation in part of my application lSerial No. 279,443,1to which. reference has been made herein.

panying drawing in which yon line 2-2 vof .Figure 1.

the opposite side of the air passage. imperforate :portions .1 lie in the same plane and .Figures 6, 'zand a are views similar to Figure' 1, but showing modifications.

Figures 9 .and 10 are detail sectional views on the correspondingly numbered section lines of Figures 6,and 8, respectively. t

l yReferring'dirsi. to Figures 1 and 2, a grill isil- -lustratedintended.for situations .where .no substantial `weight isto be borne by the grill, as,

.for example, wherefthe 'grill is placed in the Vv,ceiling 4or side wall of the room. As shown it .comprises a single plate which maybe of sheety `metal .as .at I, cut at intervals along linesgen- `erally radiating from the center 2 as at 3 and then transverse to these radial lines as at lA and 5 so as to denne tongues 6 which may be de- .ected .backwardly at an acute angle from the plane ,ofl theA sheet, therebeing formedrbetween they deected ,portions elongated imperiorate lportionsywhich asshown radiate from a central imperforatewarea Stoward an imperforatemar- .ging which maybe providedwthopenings y9af to I 30 ing the grillin position. VlThe deected portions receive vfastening means (not shown) A for rsecur- G extend backwardly from the outer face of the grill and leave elongated openings loforthe passage of the air, separated. by the imperorate Aportions 'L The imperforate portion 1 being positioned at one v4side of each of the deflected portions 6, acts eiectively therewith to define an .outer side wall-6a for the entering air which is more Isharplyinclined to thefront face of the grill than is .the opposed inner side wall 6b formed by the orwardface of the portion 6' which defines A11 of the form thefdischarge face-at the frontl of .the grill.

Theair passingthrough theopenings l0 in thismanner produces .adjacent to the free .edge of each .of theimperforate sections 'l a suction Veffect in conjunction with a critical angle deflect vbetween the wall portions 6 and 'l which tends to deflect' the air entering the room from the next adjacent passage-directly forwardly of the delectedA portion lil "in the manner shown by thef-arrow fa" in `Figure 2. This effect is produced.l Asuccessively between adjacenty pas- :sages Iaround. the circumference of the grill,

this resulting in the air coming into the room escaping from the grill in directions along the front face of the wall, the air escaping from the outer surface of this entering air layer intol the room so gradually that' no effect of draft is noticeable. Thus the air entering the room does so at an angle to the front face of the grill much smaller than the effective discharge angle of the grill passage which would be controlling as to the direction of discharge in the absence of the face of substantialwidth outwardly of each of the passages. It will be noted that the amountl to which the cut portions are turned backwardly and their widths determine the entire thickness of the grill and the widthsare determined by the spacing between the radiating lines of cut. Thus the total thickness of the grill may be reduced to a small amount by increasing the number of the cut sections. While the bending back of the cut sections acts to produce a slight spacing of the projection of the free rear edge of the sections on the plane of the front of the grill from the adjacent side of the opening, this rear edge is so far back that the current of air efectually cuts 01T any straight passage of air perpendicular to the front face of the grill. Such perpendicular passage of air is torbe avoided in accordance with this invention, as this would produce a tendency to discharge well into ie room rather than causing the discharge to rst take place along the wall surface.

The air passing along the walls 6a and escaping at the front of the grill produces a lower pressure effect over the front face of the next imperforate portion l, causing the air to be discharged laterally across the outer faces of these imperforate or uncut portions, rather than directly out into the room, as indicated by the arrow a, provided that the angle at which the outer walls 6a of the tongues E are disposed with respect to the imperfor-ate portions 'I and the discharge face of the grill is not sufcient to cause the air to break away from th outer surface of the imperforate portions.

Figures 6 to 10 illustrate constructions wherein the grill instead of being madeA from sheet metal'is provided with more substantial partitions l5 between the air passages I6, such as may be made by casting. The rear side face I1 of eachof these'partitions has an angularity to the perpendicular to the front face of the grill corresponding generally tothe rear face 6a. of

the deflected portion 6 of Figures 1 and 2', while the opposite side face I8 is that' resulting from more or less filling in between the back faces of the for-ward walls and the adjacent faces of the rearwardly deflected portions 6 of Figure 1. precise contour of the lled in portion is of no particular consequence so long as the air is directed thereby against the opposite face of the slot, as will later more fully appear. Figure 6 shows a complete circular series of partitions and openings or slots, while Figures 7 and 8 show half and quarter portions, respectively, which give a less complete arc of diffusion of the air but are particularly suitable for locations where the distribution is otherwise limited as adjacent to angular wall members or near corners of a room.

In all instances it will be noted, however, that the direction of the air discharge from the several slots is in the same direction of rotation about the central axis or axes of the partitions. The central portion of the grill which is shown as closed may be either round or oval as desired, Figure 8 showing a portion of a round center,

The

while Figures l, 6 and 7 sho-w the center as elliptical.

The best angles of the faces in all of the constructions shown, depend on various factors, such as width of lthe faces between the air openings, the smoothness of the sidel faces of the air passages and the velocity of the air entering.

Certain factors, however, have been found rather critical as follows:

(a) In a grill employing the straight slot arrangement, the length of the slot should be at least 6. inchesand the ratio of length to width of the slot should be at least 6 to l.

(b) However, in a grill employing the radial slot arrangement, the actual length of each slot is not of great importance, because the air is discharged from the grill in a fan-shaped pattern and the effective width of the air stream is many times that of the actual length of the slot.

(c) The angle at the outer side of the slot in sizes of `grill-larger than six inches diameter cannotv be much larger than 50 in order that the jet issuing from the slot will not break away from the contour of the inner wall and may be turned toward parallelism with the discharge face of the grill, and with this angle there must be an effective border or ilat wall margin 20 at substantially the plane of the face of the grill, either part of the grill itself, or a wall member in a hole in which thegrill is set `of at least substantially two inches and three is better, as shown in the diagram of Figure 3. If this angle is reduced, the effective width of the border 20 may be reduced also, and with a 40 angle may be substantially one inch, as shown in Fig. 4. Even with avery Wide border, however, the angle cannot be safely increased more than two or three degrees beyond 50. In this range the jet may become unstable, changing suddenly between substantial parallelism to the face of the grill and outwardly directed at about the angle of the outer wall of the slot. This change in angle is apparently dependent on factors difficult to determine or control. With small size grills such as those of six inches in diameter, the workable angle below the vcritical is somewhat though not much greater than with the larger sizes. The angularity of the inner wall or face of the slot to the perpendicular to the face of the grill ap pears to be `of no particular consequence so long as kthe air jet is directed against the outer wall, butin order to so direct the air jet, its sides must either converge toward the outlet or the inner wall member must have a lip or at section near toits outer edge, or the angle of diversionfrorn the axis of the outer wall must be acute enough to provide this pressure of the air against the outer wall. Where the outer wall does not extend to a point directly back of the inner edge e of the slot, or the forward edge of the Ainner wall 6b, thel air tends to break away from the contour of the inner wall at a small angle. y

In Figure 5 the line is perpendicular to the outer wall member andthe line o joins the back edge of the outer iwall member with the forward edge of the inner wall member, forming between them the angle 0. This angle 0 is the amount by which the discharge angle is greater than `parallel with the louter wall of the slot, line e With the radial arrangement of partitions and air passages shown herein, the airpasses into ythe room with a whirling tendency,` the constructions of Figures '7 and 8 causing this tendency to be less than through a complete rotation.

In connection with the present invention, a

question may arise in establishing the angle Cil which the inner wall ofthe member or the outer .side wall of the air passage makes with respect to the front face of the grill. For manufacturing, artistic or other reasons, it may be desirable to have either the wall or the face, or both of such design that there would not be any denite Aangle between the inner wall of the air passagev and they front face of the grill, yas for example, if the inner side walll of the air passage was concaved or convexed, or the face of the grill was of an irregular nature. f

In designs of uns' character, in order to determine the critical angle for the discharge of i -air through the passage, it would be necessary to rely on experience or laboratory tests to determine the turning effect of the particular de- Y, sign on an air stream delivered through the air passage. In order to limit the forward face deair stream discharged through the opening no longer clings to the contour of the deflected portion 6 and turns in a substantially lateral direction, but 'breaks away from the contour of the y deflected portion and the uncut portion l, and

flows from the front face of the grill into the room in a more nearly axial direction. y From the foregoing description of certainembodiments of thisinvention it should be evident to those skilled in theart ythat variouschanges and modifications might be made without` departing from the spirit or scope of this invention.

I claim: l. A grill comprising a plate provided with a flat front discharge face and having a series of tongue portions struck rearwardly. therefrom f `rand defining an arcuate series of-air passages separated by imperforate portions arranged around a central portion closed to the outward escape of air, all of the imperforate portions lying in the same plane and forming said front discharge face, one side face of each tongue portion forming an outer wall for an air passage,

the other sidey face of the same tongue portion forming an inner wall for the next adjacent air passage, the inner walls being shaped to direct lthe air passing through said passages against the outer walls, the outer walls having an angle-with respect to said discharge face of the grill not substantially greater than 50",'sov that the air passing through the passages will not break away from the inner walls and forward faces of the imperforate portions but will follow the contour of the inner walls kand the forward faces of said imperforate portions and be discharged substantially laterally across the discharge face of the grill.

2. A grill comprisingl a plate provided with a flatfront discharge face and having a series of tongue portions struck rearwardly therefrom and defining an arcuate series of air passages separated by imperforate portions arranged around a central portion closed to the outward escape of air, all of the imperforate portions lying in the same plane and forming said front discharge face,one side face of each tongue portion forming an outer wall for an air passage,

the other side face of the same tongue portionforming an inner wall for the next adjacent air passage, the inner walls being shaped to direct the airpassing through said passages against the outer walls, the outer walls having an angle with respect to said discharge face of the grill not less than 40 or vmore than 50, so that the air passing through the passages will not break away from the inner walls and forward faces of the vimperforate portions but will follow the contour of the inner walls and the forward faces of said imperforate portions and be discharged substantially laterally across the discharge face of the grill, said grill having an effective substantially flat front marginal face of at least substantially one inch in width, outwardly of said passages and imperforate portions.

3. A grill comprising a plate provided with a flat front discharge face and having a series of tongue portions struck rearwardly therefrom and defining a series of air passages separated by imperforate portions, all of the imperforate portions lying in the same plane and forming said front discharge face, said air passages being at least sixinches long, one side face of each tongue portion forming/'an outer wall for an air passage, the other side face of the same tongue por` tion forming an inner wall for the next adjacent air passage, the inner walls being shaped to direct the air passing through said passages against the outer walls, the outer walls having an angle with respect to said discharge face of the grill not substantially greater than 50, so that the air passing through the passages will not break away from the inner walls and forward faces of the imperforate portions but will follow the contour of the inner walls and the front discharge faces of said imperforate portions and be discharged substantially laterally across the discharge face of the grill.

ALFRED L. GREENLAW.

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