US2843366A - Convection heater - Google Patents

Description

July 15, 1958 T. K. HINE CONVECTION HEATER Filed Sept. 16, 1955 INVENTOR. 7 76176} #2713 Unite States Patent coisvirc'rioN HEATER Tredick K. Hine, Huntington Woods, Mich., assignor to Chrysler Corporation, Highland Park, Mich., a corporation of Delaware Application September 16, 1955, Serial No. 534,674

4- Claims. (Cl. 257136) This invention relates to improvements in convection heaters of the type employed for space heating.

Convection heaters of the aforesaid type are conventionally installed in rooms of oifice buildings, hotels, dwellings, and the like. In such installations the heating element is usually located in an enclosure open at the region of the floor to provide an air inlet and at the top to provide an outlet for the heated air. This enclosure is intended to provide an upright warm air stack or duct and is conventionally located adjacent an outside wall of the room and below a window.

Convection heaters conventionally installed as aforesaid have, prior to my invention, an inherent and most objectionable action in that they induce a flow of cold air currents in the rooms being heated. This gives rise to objectionable drafts of cold air which are not only disturbing to the occupants but sometimes induce colds and other disorders. These objectionable cold air drafts are of an intensity in proportion to the drop in ambient temperature which increases the discomfort of the occupants as the weather becomes colder.

It is an object of my invention to provide a convection heater of the aforesaid type adapted for installation as aforesaid but which will overcome the aforesaid objections.

Another object is to provide a convection heater of simple construction and of very low cost in relation to conventional heaters of this general type which, when installed adjacent and below a window, will operate efficiently in heatingthe room to the desired temperature without accompanying cold air drafts.

A further object is to provide a simple means capable of attachment to many commercial types of convection heaters whereby they may be readily and quickly converted at low cost so as to attain the aforesaid objects of my invention.

In carrying out my invention 1 provide, in instances of conventional normal depth sills, a convenient form of baffle projection from the inner rear wall of the upright warm air stack toward the inner front wall thereof and disposed between the heating element and the stack outlet. This baflie terminates short of the inner front wall so as to deflect the current of cold air falling downwardly adjacent the window glass and divert it upwardly into a stream of warm air by merging with the warm air currents passing toward and from the outlet of the convection heater. The baffle further produces a jet or venturi-like action on the warm air in that in rising to the restriction provided by the space between the baffle and the inner front wall of the stack, the velocity of the warm air is accelerated and thus effectively diverts the falling cold air and causes it to flow upwardly with the warm air. As a result there are no cold air downdrafts, as heretofore, either through the stack or adjacent thereto and the room occupants are not aware of any flow of air currents.

In instances of relatively wide sills which are sometimes experienced, my invention contemplates location of the aforesaid baffle projection from the inner front wall of the upright warm air stack toward the inner rear wall thereof and disposed, as aforesaid, between the heating element and the stack outlet. This bafl'le terminates short of the inner rear wall so as to deflect the aforesaid current of cold falling air and divert it upwardly into a stream of warm air as aforesaid. Such arrangement produces the aforesaid venturi-like action by acceleration of the rising warm air with the same beneficial results but with this difference, that is, in this instance the falling cold air is deflected upwardly largely at the zone of the wide sill area.

Further objects and advantages of my invention will be apparent from the following detailed illustration of several embodiments thereof, reference being had to the accompanying drawing in which:

Figure 1 is a front elevational View of my convection heater illustrated in operative position adjacent and below a window;

Figure 2 is a sectional elevation view -2 of Figure 1;

Figure 3 is a diagrammatic view illustrating typical air current flow for my convection heater;

Figure 4 is a similar view illustrating typical air current flow for a conventional convection heater; and

Figure 5 is a view generally similar to Figure 2 but illustrating my convection heater applied to a relatively wide sill adjacent a window.

In the drawings the convection heater A is shown installed adjacent and below the window B of the outside wall B of the typical room C. This heater is provided with an upright warm stack or duct lit having the sheet metal opposed front and rear wall portions 11 and 12 respectively, opposed upright end walls 12', and the bottom boundary 13 which, in this instance, is the room floor. At its upper end the duct is provided with an outlet grille 14 for the warm air and, for the sake of appearance, is preferably flush with the window sill 15' which, in this instance, is of normal relatively narrow depth. For the same reason of appearance the duct is provided with a finish enclosure 16 which terminates short of the floor 13 to provide an air inlet 17 to the heating element 18 mounted adjacent the inlet and across the lower end of the sheet metal duct 12 so that the air entering the inlet 17 passes through the heating element.

The heating element 18 may be of any well known type such as hot water, electrical, or steam. Extending from the inner face of the rear wall 11 of duct it) and fixedly secured thereto is a battle D of heat resistant material such as ordinary tin or other metallic sheeting which extends longitudinally within and preferably the length of the duct. This bafile D provides a restricted warm air orifice 19 preferably closer to the outlet grille 14 than to the heating element 18. Although the baffle D may be of any shape, such as a planar sheet metal element extending perpendicular to the rear wall 11, I preferably provide an inclined baffie, which in addition may be concaved downwardly as illustrated, in order to minimize eddy currents in the upward flow of warm air and thus increase the elliciency of the air flow. I have obtained good results with the bafile arranged generally as illustrated, that is, such that the orifice 19 is roughly onequarter to one-fifth of the distance from the grille 14 to the heating element 18. The baffle D divides the duct 10 into zones or portions as follows.

The duct portion 20 below baffle D comprises a warm air riser leading upwardly from the heating element 18 to the orifice portion 19 between the baffle and wall 12. Above the bafile is a duct portion 21 adjacent the bottom of window B while above the orifice 19 there is a portion 22 of warm air of accelerated velocity relative to that of the warm air below the bafile.

taken along line With the heater A arranged generally as illustrated in relation to the window B, the naturally induced cold downdraft of air, indicated by solid arrow lines 23, enters the grille 14 into duct portion 21 and is caused to reverse its flow as it is deflected by the high velocity warm air, indicated by dotted arrow lines 24, rising from duct portion 20 and orifice portion 19 whence it is entrained in region 22 with the cold air. Thus the cold air is isolated or shielded from the room by a curtain of warm air rising from orifice 19 throughout the length of the heater A and window B. The falling cold air is prevented from passing from the window to the room and is caused to flow into the duct portion 21 for entrainment with the warm air discharged through orifice 19. The cold air is thus mixed with the warm air and both travel upwardly to the ceiling and thence generally as indicated in Figure 3 in a looping path for the length of the room and back along the floor to the inlet 17. It will-be noted that the cold air, although naturally induced in downward currents along the window, cannot escape downwardly through the heater A or externally adjacent there- I have illustrated in Figure 4 a conventional heater which does not include my baffle D. Here the cold air downdraft generally follows the solid arrows 23'-flowing downwardly into the heater A 'and out of the inlet 17 and also externally adjacent the heater to set up the aforesaid cold drafts in. a looping counterflow with relation to the warm air flow 24. The latter is obviously inefficient as the cold air entering the grille 14 prevents escape of the warm air. I have observed that these grilles of conventional heaters on cold days are warm only in spotty areas such as adjacent the opposite ends. In contrast, I have found that my grille is uniformly warm above orifice 19 throughout the length of the grille.

In Figure 5 I have illustrated a modified form of my invention which may be employed to advantage especially in instances of a relatively wide sill 15' adjacent-the window B. In this instance the falling cold air currents 23 are so horizontally or laterally spaced from the grille 14 that these cold air currents do not have the aforesaid degree of tendency to travel downwardly through the stack 10. In such instances it is feasible to provide the curtain of accelerated rising curtain of warm air adjacent the inner rear wall 12 of stack 10. Thus in Fig. 5 my baflle D is fixedly mounted to the inner front Wall 11 of stack 1th to provide the orifice 19' between the rear edge of the baffle and wall 12 for acceleration of rising warm air for mixing with the falling cold air 23.

, In this instance the falling cold air is largely deflected upwardly at the region of sill 15 but the same beneficial results as aforesaid in reference to Figs. 1 to 3 are obtained. The relatively wide or deep sill 15' somewhat baflles the falling cold air so that it may be diverted upwardly by the rising warm air concentrated at the region above orifice 19 adjacent the inner rear wall .12 of stack 10. Otherwise the resulting effects in heating the room are identical with that aforesaid in reference to Figs. 1 to 3, it being understood that the lower end of stack of Fig. 5 is the same as Fig. 2 including the heating element 18 and inlet 17.

My invention is not to be confused with so-called volume controlling adjustable dampers hingedly mounted within the duct for regulating the flow of air therethrough. With such devices the damper is progressively opened in proportion to drop in ambient temperature and is fully open for very cold weather conditions which induce the aforesaid cold downdrafts and permit them to set up the objectionable cold air drafts or currents in the room. With such prior devices cold downdrafts are induced for flow into the room at greaterrand greater intensity as the'ambient temperature becomes colder and colder. My baifle requires no adjustments as it is constantly operating to effect the aforesaid deflection of the cold air downdraft regardless of variation in outside air temperature and resulting variation in velocity of these downdrafts. Thus my baffle is preferably fixedly or permanently mounted in position in the sense that it is not adapted for adjustment in its day to day operation to regulate the volume of warm air discharged from the duct in proportion to variations in ambient temperatures. The only variable desirable to the maximum efficiency of my heater is the temperature induced in the heating element 18 which obviously should be maintained at a higher degree as the ambient temperature decreases.

The structural details herein disclosed for the purpose of illustrating several forms of my invention may be widely varied without departing from the substance of the invention, or sacrificing the advantages thereof, and hence I do not limit my invention to the specific structure disclosed, except to the extent clearly indicated in specific claims, but reserve all such variations, modifications and equivalents as fall within the spirit and mm view of the claims.

I claim:

1. In a convection heater for use in a room adjacent a cold outside wall, an upright. air stack having an air inlet opening into said room adjacent the floor thereof and also having an air outlet opening upwardly into said roorn adjacent said wall at an upper portion of said stack for vertical passage of heated air into said room, a heating element in said stack between said inlet and outlet for heating air entering said inlet, means to prevent downwardly flowing cold air adjacent said wall from entering said stack through said outlet and thence discharging from said inlet into said room comprising a baffle above said heating element and underlying a substantial rear portion of said outlet, said baffle extending from the rear of said stack toward the front thereof to define a restricted orifice in said stack between said heating element and outlet,

and means located above said heating element and closing the space between said wall and the rear edge of said outlet and also closing the space between said wall and the rear edge of said baifle proximate said wall to block said downwardly flowing cold air from flowing into both spaces, said bafile being arranged to direct upwardly flowing air in said stack toward the front thereof through said orifice, the latter cooperating with said baffle to block cold air flowing downwardly adjacent said wall from above said outlet and to effect reverse flow of said cold air with the warm air flowing upwardly through said orifice.

2. In a convection heater for use in a room adjacent a cold outside wall, an upright air stack having a forward surface spaced from said wall, said stack having an air inlet opening forwardly into said room adjacent the floor thereofto receive air from said room and also having an air outlet opening upwardly into said room for vertical passage of heated air thereinto, said outlet being adjacent said wall at an upper portion of said stack, a heating elementin said stack between said inlet and outlet for heating air entering said inlet, means to preventdownwardly flowing cold air adjacent said wall from entering said stack through said outlet and thence discharging from said inlet into said room comprising a baffle above said heating element and underlying a substantial rear portion of said outlet, said baflle extending forwardly from the rear of said stack and terminating at a forward edge short of said forward surface to define a restricted orifice in said stack between said heating element and outlet,-

and means located above said heating element and closing the space between said wall and the rear edge of said outlet and also closing the space between said wall and the rear edge ofsaid baffle proximate said wall to block said downwardly flowing cold air from flowing into both spaces, said baffle being arranged to direct upwardly flowing air in said stack toward said forward surface and through said orifice, the latter cooperating with said baffle to block cold air flowing downwardly adjacent said wall from above said outlet and to effect reverse flow of said cold air with the warm air flowing upwardly through said orifice.

3. In a convection air heater for use in a room adjacent an outside wall, a housing containing an upright air stack having a forward surface spaced from said wall, said stack having an air inlet opening from said room adjacent the floor thereof and also having an air outlet adjacent said wall and opening upwardly into said room from an upper portion of said stack for passage of heated air vertically through said outlet, a heating element in said stack between said inlet and outlet, said housing having a portion closing the space between said wall and the edge of said outlet proximate said wall to block the downward flow of cold air adjacent said wall and into said space, and means to prevent downwardly flowing cold air adjacent said wall from entering said stack through said outlet and thence discharging from said inlet into said room comprising a baflle above said heating element and underlying a substantial rear portion of said outlet, said baflie inclining from the rear of said stack to a forward edge of said baffle spaced from said forward surface to define a restricted orifice in said stack between said heating element and outlet, said bafile being arranged to direct upwardly flowing air in said stack toward said forward surface and through said orifice, the latter cooperating with said baflie to block cold air flowing downwardly adjacent said wall from above said outlet and to eifect reverse flow of said cold air with the warm air flowing upwardly through said orifice.

4. In a convection air heater for use in a room adjacent an outside wall and below a window, a housing containing an upright air stack having a forward surface spaced from said wall, said stack having an air inlet opening from said room adjacent the floor thereof, said housing having a top member adjacent the sill of said window and containingan air outlet adjacent said wall and opening upwardly into said room from said stack for passage of heated air vertically through said outlet, said top member closing said stack except for said outlet and also closing the space between said wall and the proximate edge of said outlet to block downwardly flowing cold air adjacent said window from flowing into said space, a heating element in said stack between said inlet and outlet, means to prevent said downwardly flowing cold air from entering said stack through said outlet and thence discharging from said inlet into said room comprising a bafile above said heating element and underlying a substantial rear portion of said outlet, said baffle inclining forwardly from the rear of said stack and terminating at a forward edge short of said forward surface to define a restricted orifice in said stack between said heating element and outlet, said baffle being arranged to direct upwardly flowing air in said stack toward said forward surface and through said orifice, the latter cooperating with said baffle to block cold air flowing downwardly adjacent said wall from above said outlet and to effect reverse flow of said cold air with the warm air flowing upwardly through said orifice, and a baflle portion connecting said top member and the first-named batfle to close the space between said first-named baflle and wall to block air flow into the latter space.

References Cited in the file of this patent UNITED STATES PATENTS 1,288,236 Shipp Dec. 17, 1918 1,608,938 Henshall Nov. 30, 1926 1,856,925 Modine May 3, 1932 1,916,355 Bennett July 4, 1933 2,022,333 Woolley Nov. 26, 1935 2,144,466 Stikeleather Jan. 17, 1939 2,345,537 Keep Mar. 28, 1944 FOREIGN PATENTS 1,927 Australia May 2, 192 7

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