US2396939A - Heating assembly baffle construction - Google Patents

Description

March 19, 1946. E. W. BROWN I 2,396,939

I HEATING ASSEMBLY BAFFLE CQNS'ITRUC'IION Filed July 2, 1942 Q 2 Sheets-Sheet l fiwooo M Bean 1v.

E. W. BROWN HEATING ASSEMBLY BAFFLE CONSTRUCTION March 19, 1945.

' Filed July 2, 1942 2 Sheets-Sheet 2 lllllllllllllllll Illlli ll|.l|l lll nz En :r" W D PM 520W.

Patented Mar. 19, 1946 HEATING ASSEMBLY BAFFLE CONSTRUCTION Elwood W. Brown,

Chicago.

11]., assignor to Coles Hot Blast Mfg. 00., Chicago, 111., a corporation of Illinois Application July 2, 1942, Serial No. 449,414

2 Claims.

My invention relates to hot air heating units and is directed more particularly to the class of units known as the floor type, that is, they are sunk into an orifice in the floor of a room and covered by a grating which is disposed in the same horizontal plane as the floor.

An important object of my invention is to provide a construction of the above character which may be disposed against portions of the inflammable floor material or against joists which support the floor without overheating the same and thus creating fire hazards.

Another important object of my invention is to provide against the overheating of a floor or joist as above set forth by the use of an auxiliary flow of air.

Still another object of my invention is to provide an auxiliary flow of air as above de-' scribed without detracting from the heating efliciency of the unit as a whole.

Another object of my invention is to provide a. heating unit which is so constructed that it utilizes a secondary or auxiliary air flow for cooling the parts thereof adjacent th floor and joists, this secondary air flow being further utilized to combine with the primary hot air ejection from the device to render more comfortable temperatures in the space being heated.

A further object of my invention is to provide, in a heating device of the above character, a secondary air flow for the purposes above set forth, this secondary air flow being created entirely automatically and without the use of auxiliary power units.

Another object of the invention is to provide an improved heating unit construction in which cross flow or cross eddies are prevented by a novel bafiie construction.

It is a further object of the invention to provide a heating unit in which a secondary flow of air is provided, this secondary flow being directed so that it avoids contact with the primary heating element and so that it serves as a diluent fOr the primary hot air stream.

Still another object of my invention is to provide a heating unit which is so constructed and arranged that there is aiforded a passage between the supporting joists and the primary heating element, this passage being adapted to receive a flow of air independent of the main heated air flow.

In accordance with the general features of my invention there is provided herein a heating unit which includes an outer casing element in which is disposed a primary heating drum for heating the primary hot stream, a shell-like chamber entirely enclosed from the central chamber enclosing the heating drum, this shelllike chamber being disposed on the inner surface of the casing member, and a separating baflie extending part way downwardly into said chamber to divide the same into up and down flow passages, the down passage being disposed on the outward side of said chamber and the up passage being disposed inwardly thereof and having a mouth which is swept by the up flowing primary hot air stream whereby a siphoning action occurs to draw cold air into the down passage of said chamber to retain the adjacent portions of the casing at a reduced temperature, the air flowing through said up passage serving as an insulator for the down passage whereby the air therein will not become over heated and thus dwell to retard or inhibit the flow of secondary air.

Other objects and advantages of the invention will become apparent from the following description and accompanying drawings, in which:

Figure 1 represents a top plan view of a heating element embodying my invention;

Figure 2 represents a cross section taken on the line II--II of Figure l;

Figure 3 represent a cross section taken on the line IIIIII of Figure 1;

Figure 4 represents a fragmentary cross section of a modified form of the invention.

It is to be understood that the modification shown herein is for illustrative purposes only and may be changed or modified without departing from the spirit and scope of the invention as set forth in the appended claims.

In heating units of the character here involved it has been found that the entire sheet metal construction thereof, including the outer casing, inevitably becomes heated to elevated temperatures and thus, when installed in such a position that they hang from the floor of the room which is to be heated, preferably in a position so that the side walls of the casing member abut joists, that the contact between the heated casing and the wooden joists creates a highly undesirable fire hazard. For this reason the various inspecting and regulating authorities, under whose supervision heaters are manufactured and sold to the public, have passed regulations requiring some form of insulation between the various parts of the heating unit and the adjacent wooden structural members, or some form of heating unit in which the portions thereof in contact with the wooden members are maintained at reduced temperatures far below those at which the lir hazard exists.

In providing a construction to meet the above mentioned regulations it is desirable first that the construction provided be such that the ultimate heating qualities of the unit be reduced not at all or at least a minimum amount, and that insulating materials generally known and used be avoided since they are known to absorb moisture from the air and thus when in contact with the wooden members tend to rot the same.

To the end that the above objects may be obtained and the above mentioned disadvantages be eliminated, there is provided herein as shown in Figures 1, 2 and 3, a heating unit adapted to be suspended below the level of the floor members l and between joists ii and 112, respectively.

The unit includes an encompassin casing it of any desired shape, but preferably having straight sides to provide a flush engagement with the respectiv joists, this casing being divided generally into a cold air column id and a hot air column l by means of a transversely dis osed baffle ['6 which extends part way downwardly into the interior of the casing as shown in Fi ure 2, to afford an air passage the purpose of which will be described presently. The air columns M and B5 are completely covered by suitable grilles or grates l1 and H3 respectively through which cold air is drawn downwardly into the column i i and through which this a r. when heated in the column I5. passes upwardly to heat the room in which the unit is dis osed.

In the cold air column Hi there is provided any suitable fuel flow control device it and any suitable burner and i nition device 2d, the latter communicatine throueh a fiue 2!! with a heating drum 22 mounted on the bottom of the casing is by suitable standards 23. An outlet flue 2 is provided at the bottom portion of the drum 22 and on the side o posite from that connectin with the inlet flue 2 i. The flue 26 is adapted to d liver the expended products of combustion to a suitable chimney or the like.

From the foregoing it will be seen that. due to the discharge of ignited gases through the flue 2! info the drum 22, the latter attains a very high temperature and accordingly the associated sheet metal parts of the unit are also heated to high temperatures due to heat both radiated and conducted from the drum 22.

As will be seen more clearly from Figures 2 and 3 the upper margins of the outer surface of the casing [3 are disposed in adjacency to the joists l I and i2 when the heating unit is suspended from the floor structure in the intended manner. If these portions of the casing l3 are permitted to attain the elevated temperatures which would result normally from the association of the casing with the drum 22 the tinder point of the joists would be approached or exceeded with the result that the structure in which the heating unit was mounted would be ignited.

To the end that these elevated temperatures be avoided at the aforementioned points of the assembly, some means must be provided for ither avoiding contact between the metallic portions of the unit and the joists as by the usual non-inflammable insulating material, or these portions of the unit must be subjected to cooling air.

As stated previously, if the first means above mentioned is utilized condensation takes place in the insulating material with. the result that the joists and any other abutting wooden portions ecome rotted and thus deteriorate.

If the portions of the unit which abut the 301565 are maintained at reduced temperatures by means of cold air flow it has been found that this must be accomplished in such a way that the normal upward flow of hot air is not reduced in velocity and further that the emitted hot air is not mixed with. cold air of such a reduced temperature that the temperature of the entire output through the grate i8 is reduced materially.

As shown herein there is provided a novel cool ing chamber-bathe construction which maintains the upper portion of the casing at reduced temperatures without the use of auxiliary impelling mechanisms. At the same time cool air is swept along the inner surface of the casing and is ex pelled in a heated condition so that it does not materially reduce the temperature from the grate it. instead the expelled air somewhat tempers the upwardly rising air which has previously been in contact with the heating drum 22 to the cue that it is not overheated.

This chamber-baille construction, as SllOWn in Figures 1, 2 and 3, includes generally a wallassembly having side sections 25 and end sections 26 which are disposed part way down and parallel to the walls of the hot air column i5 and have closing end sections Z'l and 28, respectively. As will be seen more clearly from Figure 2, one of the joists H abuts the section of the casing it which comprises one Wall of the cold air column M. Consequently, it is unnecessary for this section to be cooled in any manner since it does not normally reach elevated temperatures due to its distance from the drum 22 and the insulation provided by the column of cold air i4. However, the Wall section 23 at that end of the unit is secured to the inner surface of the battle 5 6 relative to the hot air column it so that the baiile may be cooled to a degree, as will be explained presently, to pre vent overheatin or the air passing downwardly of the column i i. The upper edge margins of the sections 25 and 2b are turned inwardly and some what over the drum 22 as at 29 and til. respectively.

Disposed intermediate the sections 25 and 26 and the adjacent sections of the casing it are baiile members 3i and 32, respectively, which eX- tend part way downwardly into the chambers passages formed by the respective sections 25 and 2%. These bafiles are suspended in their relat ve positions by vertically disposed $-irons which serve the additional purpose or maintaining the air how to be described presently on a true vertical path to prevent cross eddies which are well known in the art to be detrimental to heatin systems such as those here involved. The upper ends of the intermediate baffles 3i and 32 are turned inwardly at 34 and 35, respectively, and the upper edges thereof terminate just shortof their vertical plane through the respective mwardly turned sections 29 and 30, previously described.

In the above described assembly ignited gases are blown into the drum 2.2 by means of the assembly Zil in the usual manner. The ai at re t in the column !5 is then heated with the result that it immediately begins to rise and, in rising. creates a displacement which draws air from the room to be heated downwardly through the grille H and into the air column i l. The cool air then passes transversely beneath the baffle 16 and into contact with the heating drum 22 and the cycle is thus continued. The above cycle of air flow is shown clearly in Figure 2 by means of the long shafted arrows.

As shown most clearly in Figures 2 and 3, the rising hot air, after enveloping the drum 22 and immediately prior to its passage through the grate i8, passes by the slot formed between the inturned sections 29 and 34 and 3B and 35, respectively, to sweep past the same and thus to create a low pressure area in the vicinity thereof. In thi manner the air at rest between th bailies 3| and 32 and the respective section 25 and 26 moves upwardly in a substantial vertical path due to the presence of the S-irons 33 to create a displacement at the lower end of the space between said baffle and said section and a further displacement in the chamber formed at the lower ends of the sections 25 and 26. It will also be seen that due to the inwardly turned sec tions 3%] and 35 the rising column of hot air driven towards the center of the grate l8 and thus is prevented from passing upwardly through the marginal edge portions thereof. As shown by the arrows 35 in Figures 2 and 3, the displacement of the air in the manner just described creates a low pressure area at the marginal portions of the grate 58 whereby room temperature air, which is cool and considerably below the tinder point of the j ints I I and i2, pa ses downwardly into the space between the battles 3| and 32 and section 25 and 25, respectively. this air coming into immediate contact with the inner surface of the upper marginal portions of the casing l3 to retain the same at substantial room temperature due to the presence of the air flowing thereby.

As this sec ndary supply of ai passes downwardly as indicated by th short staff arrows and starts to rise in the column formed between the sections 25 and 2B and the respective bafiles 3| and 32, it is drawn into closer proximity with the heating drum 22 with the result that it is elevated in temperature thus having a greater tendency to rise and greatly augmenting the downward flow of the cold air in the outer pas sage as created by the siphoning action at the slot formed between the members 29 and 34 and 3D and 35.

While this rising column of air is heated t a degree, it will be seen that its disposition be tween the downwardly moving column of secondary air and the drum 22 provides insulation to retain the downwardly moving column of air at a reduced temperature. Thus, movement of the secondary flow of air is not reduced or retarded.

It will be understood of course that if desired the chamber beneath the intermediate baflies 3! and 32 may be decreased in size as shown in Figure 4, under which circumstances the air emitted from the slot between the members 30 and 35 will not be heated to the degree attained with the foregoing structures and thus the tempering effect of the secondary flow of air will be greater upon the primary flow of ai from the drum 22. In Figure 4, the inner section is indicated at 2512, the bottom of the chamber at 211), other parts being designated a in the previous figures.

It will be further understood that other ex pedients may be provided for supporting the heating unit on the joists in point contact with metallic members which are secured to the joists for supporting purposes.

From the foregoing it will be seen that there is provided herein a heating system in which the sections of the device adjacent wooden joists and the like are insulated from the heating drum by a moving blanket of low temperature ai which may be a secondary air flow of a dual air flow system. The primary upward air flow constitutes that heated rising air which has enveloped the heating drum and this primary upward now constitutes the impetus by which cooling air is drawn downwardly to sweep the surfaces of those sections of the device which engage wooden joists and the like to maintain those surfaces considerably below the tinder point of the joists. Consequently no additional air impelling mechanism is required for producing the secondary, cooling air flow since such flow automatically starts with the natural upward movement of the primary heated air. Furthermore, there is provided herein a construction which affords a secondary cooling air flow as above described which in no manner reduces the velocity of the primary air flow or detracts from the output of primary heated air from the device for heating the space in which the unit is installed. There is also provided a heating unit which is so constructed that cross eddies are avoided in the secondary air flow and in which the secondary air flow affords a tempering effect upon the heated air emanating as the primary air flow. There is also provided a construction in which the secondary cooling air is drawn from the room being heated and thus obviates the use of extremely cold air for the purposes described.

I claim as my invention:

1. In a hot air heater assembly including a casin open at the top and adapted to be mounted in juxtaposed relation to the joists of a floor, a heatin drum in the casing, and an exhaust gas flu extending from the heating drum through one wall of the casing, the improvement which comprises a partition wall within the casing extendin transversely thereof between the side walls of the casing and in spaced relation to the bottom wall and to one end wall of the casing and to the heating drum, said partition wall defining within the casing a main cold air passage and a hot air passage, with the heating drum disposed in the hot air passage, and said passages being in communication with each other at the bottom of the partition wall, an inner wall member surrounding the heating drum within the hot air passage and spaced from the casing walls, said partition wall, and said heating drum and defining with the casing walls and said partition wall an auxiliary cold air passage open at the top, said auxiliary cold air passage being in spaced relation to said exhaust gas flue, means connecting the bottom of said inner wall memher to the adjacent casing walls and partition wall, to thereby seal the auxiliary cold air passage from the hot air passage and from the main cold air passage, a baffle member in the upper portion of the auxiliary cold air passage disposed in substantially spaced parallel relation to the inner wall and to the casing walls and said partition wall and terminating above said sealing means to define at the uppe end of said auxiliary cold air passage inner and outer passages in communication with each other at the bottom of said baffle member whereby cold air is drawn downwardly through the outer passage by the upward flow of air along the inner face of the inner wall member due to proximity of the latter to said heated air passage.

2. In a hot air heater assembly including a casing open at the top and adapted to be mounted in juxtaposed relation to the joists of a floor, a heating drum in the casing, and an exhaust as flue extending from the heating drum through one wall of the casing, the improvement which comprises a partition Wall within the casing extending transversely thereof between the side wall of the casing and in spaced relation to the bottom wall and to one end wall of the casing and to the heating drum, said partition Wall clefining within the casing a main cold air passage and a hot air passage, with the heating drum disposed in the hot air passage, and said passages being in communication with each other at e bottom of the partition wail, an inner wall mom ber surrounding the heating drum within the hot air passage and spaced from the casing walls, said partition wall, and said heating drum and defining with the casing walls and said partition wall an auxiliary cold air passage open at the top, said auxiliary cold air passage being in spaced relation to said exhaust gas flue, means connecting the bottom of said inner wall memher to the adjacent casing walls and partition wall, to thereby seal the auxiliary cold air passage from the hot air passage and from the main cold air passage, a bafiie member in the upper portion of the auxiliary cold air passage disposed in substantially spaced parallel relation to the inner Wall and to the casing walls and said partition wall and terminating above said sealing means to define at the upper end of said auxiliary cold air passage inner and outer passages in communication with each other at the bottom of said baflie member, said inner passage terminating at the upper end thereof in communication with the upper end of the hot air passage, whereby cold air is drawn downwardly through the outer passages by the upward flow of air along the inner face of the inner wall member due to proximity of the latter to said heated air passage, and to the flow of heated air upwardly in said hot air passage past the open end of the inner air passage.

ELWOOD W. BROWN.

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