US2033402A - Heat exchanger - Google Patents

Description

March 10, 1936. A A L. sMlTH 2,033,402

HEAT EXCHANGER Original Filed March 27, 1933 IN VEN TOR.

d 12; f fizz /Mr Lergy 5197/ Patented Mar. 10, 1936 v UNITED STATES. PATENT OFFICE.

HEAT EXCHANGER Arthur Leroy Smith, Bryn Mawr, Wash.

Original application March 27, 1933, Serial No. 662,877. Divided and this application June 27, 1935, Serial No. 28,595

4 Claims. (Cl. 257245) My invention relates to a heat exchanger or a Fig. 1, showing one manner of ribbing heat exheat exchange unit of a form adapted for use in change walls to afford expansion to said walls, to heating systems and this application is a division reinforce and strengthen the walls and to afford of my prior application Serial Number 662,877, partition or baiile means in the passageways adfiled, March 27, 1933, for Furnaces. jacent to said walls. 5

The general object of my invention is to pro- Fig. 3 is a fragmentary vertical sectional view vide a heat exchange unit wherein an interof a furnace showing a preferred installation of change of heat between a temperature imparting my heat exchange unit. fluid and a fluid to be tempered may be very Fig. 4is a detached perspective view of a cleanquickly and eiflciently brought about. er or scraper device embodied in this heat ex- 10 Another important object of my invention is to changer. provide a heat exchange unit which possesses a Like reference numerals designate like parts very large area of heat exchange surface in prothroughout the several views. portion to the size of said heat exchange unit. Referring to Figs. 1, 2, and 3, I show a heat Another important object is to provide a heat exchange unit embodying a plurality'of, prefer- 15 exchange unit by which a very large proportion ably rectangular, substantially parallel heat conof the heat generated by the combustion of fuel ductive walls I2 which are spaced apart a short in a furnace, fireplace, stove or the like may be distance to afford two sets of passageways I3 picked up and rendered available for heating and I4 respectively therebetween, the passagepurposes, ways of said two sets being alternately positioned 20 Another object is to provide a heat exchange and extending at right angles to each other. unit in which the travel of the fluid to be tem- Closure members I5 are provided at two opposite pered is in a direction substantially at right edges of the passageways I3 and other closure angles to the direction of travel of the temperam mb rs a provided at the pp edges ture imparting fluid, thus making it possible, of the passageways I4. These closure members 5 where this heat exchange unit is incorporated in are preferably in the form of smallchannel bars a furnace, to pick up such a large proportion of turned with their channel sides-outwardly and the heat from the heated gases that the temperahe Wall may b of Sh m l and y be ture of said heated gases at the location of diswelded to said channel bars, as at IT, preferably charge from the heat exchange unit is lower near the outer edges of the side flanges of said 30 than the temperature of the air in the air takechannel bars, thereby forming a unitary strucoif conduit. ture which is fluid and gas tight. By positioning Another important object of the invention is to the closure .members I5 at the two sides of the provide a heat exchange unit of the type herein passageways I3 which are at right angles to the 5 disclosed in which suitable partitions are formed two sides of passageways I4 at which the closure 5 by folds in the sheet metal of which the walls members I 6 are positioned I obtain two sets of of the heat exchange unit are constructed, said passa eways l3 a 14 respectively w ic xpartitions affording expansion means which pretend at right angles to each t e This afiords vents buckling of the said walls due to changes an ideal heat exchange unit which makes it pos- 40 of temperature, and said partitions providing sible to permit a gravi y circulation f 40 additional heat radiating surface and further perature imparting l d or agent oug one set serving to divide the air circulation spaces into of pass way n a vity irculation of a passageways, whereby more efficient heat exfl 0 a e which is being mp e through change is obtained. the other set of passageways. It is also adaptable Another object is to provide a simple and efto a forced circulation of either or both of the 45 ficient cleaner means in combination with a heat fluids. By thus causing the two different fluids exchanger of this type. or agents to travel through thepassageways I3 Other and more speciflc objects will be apand I4 in directions at substantially right angles parent from the following description taken in to each other I am able to more than equalize connection with the accompanying claims. the temperature of the two fluids as hereinafter 50 In the drawing, Figure 1 is a. fragmentary perexplained and thus to obtain a higher heat exspective view, with parts broken away, of a heat change efiiciency than it is possible to obtain by exchange unit constructed in accordance with causing the two fluids to travel substantially my invention. parallel with each other. The narrow passage- Fig. 2 is asectional view, one larger scale than ways I3 and I4 further serve to bring a large 55 amount of the fluids in both sets of passageways into direct contact with the relatively great area of thin heat conductive walls thereby contributing to the high efliciency of this heat exchange unit.

The heat exchange unit may be very quickly and easily built up at a relatively low cost in almost any sheet metal shop by welding the walls or plates l2 to the channel shaped edge members l5 and IS.

The walls l2 of the heat exchange unit are provided t one or more locations with horizontally extending ribs is preferably formed by bending. These ribs I 9 stifien and reinforce the walls I2 and also act as horizontal partitions or baflie means for dividing the air passageways into horizontal compartments. This tends to prevent the air which is passing through these compartments from rising to the top of the unit as it is heated, a thing I have found in practice that it will do. These ribs l9 further act as expansion means and permit the walls l2 to expand and contract without buckling when they are subjected to changes of temperature. Said ribs l9 also provide more heat radiating metal surface or area in the air passageways I3. I have shown these partitions only in the air passageways I 3 but may also provide them in the hot gas passageways I4, provided the cleaner means, hereinafter described, is omitted.

The channel shaped edge closure members l5- and flame as it provides an air pocket along these edges which has been found to be effective in preventing damage to these channel members by the heat and has further been found to oifer less resistance to the upward flow of hot gases than would be offered by flat surfaces flush with the edges of the walls l2 in this location. When the channel members l5 and I6 are thus turned with the flanges outwardly it allows the side plates l2 to be welded along the edge portions of the flanges as indicated by I! and for this reason aifords more flexibility at the location of the weld and tends to prevent the side plates from breaking loose along the weld.

In Fig. 3 I have' shown a preferred installation of my heat exchange unit in a furnace. In this figure 20 designates a furnace having a heat exchange unit installed in an inclined position in the upper portion thereof, the arrangement of the heat exchange unit being such that the two sets of passageways l3 and I extend at angles of approximately forty-five degrees relative to the vertical or horizontal, it having been found that approximately this angular position is productive of the best gravity circulation of both heated gases and air. The furnace 20 has a chamber 2| positioned below the heat exchange unit and in communication with one set of passageways l4. This chamber 2| preferably communicates with a combustion chamber 22.

Air may be admitted to the passageways l3 of the heat exchange unit through a cold air intake conduit 23 and taken off through a warm air take-off conduit 24, as indicated by arrows A. The hot gases enter the passageways H from the chamber 2| and after traveling said passageways may pass into a chamber 25 and be discharged through a smoke pipe or flue 216, as indicated by darts D. I As a means for keeping the walls of the hot gas passageways clean and free from soot, I preferably provide a cleaner Figs. 3 and 4, embodying a cross bar 40 movably supported immediately below the heat exchange unit and connected with an operating bar or handle 4| which extends out through a side of the furnace housing. Fingers or cleaning members 42 are secured to the cross bar 40, and extend into the hot gas passageways. The bearing of handle 4| in the furnace housing may support the cleaner. Grasping handle 4| and moving the fingers of the cleaner back and forth in the hot gas passageways will dislodge soot which may adhere to the walls of said passageways thus permitting such soot to drop down into the lower furnace chambers or to pass out through the flue. This affords a very quickly and easily operated cleaning means which encourages frequent cleaning. It will be noted that all surfaces of this heat pick up unit which are exposed to the accumulation of soot are substantially vertical whereby the tendency to collect soot is minimized and also that the heat exchange unit is positioned so that soot which does adhere to these surfaces and is dislodged therefrom will drop down out of the heating unit.

By the use of this heat exchange unit in a furnace, it is possible to raise the temperature of the air which issues from the heat exchange unit above the temperature of the gases which are discharging from said heat exchange unit. The reason that this is possible is because the air to be heated is supplied at all elevations to the air passageways. The lowermost strata of this air becomes highly heated and the ascending gases correspondingly cooled. These gases being cooled as they rise are constantly coming in contact with walls over which cooler air of the upper strata in the air spaces is flowing with the result that this cooler air picks up heat from the gases which could not be picked up by the warmer air in the lower portion of the air spaces thus cooling the gases considerably below the temperature of the warmer air. When the air passes out of the air spaces into the air take off conduit 24 warmer and cooler strata of this air immediately commingle and mix with the result that the discharging warm air has a higher temperature than the discharging cooled gases. This tendency is accentuated by the use of the baflies or partitions IS in the air spaces.

The foregoing description and accompanying drawing clearly disclose a preferred embodiment of my invention but it will be understood that this disclosure is merely illustrative and that such changes in the invention may be made as are fairly within the scope and spirit of the following claims.

I claim:

1. A heat exchange unit embodying a plurality of spaced apart heat conductive sheet metal walls forming two sets of passageways therebetween, said walls having reinforcing folds provided therein, said reinforcing folds extending into said passageways thereby forming partition and deflector means in said passageways; means closing the'passageways of each set at two opposite sides, the closed sides of one set of passageways being positioned at approximately right angles to the closed sides of the other set of passageways.

-2. In a heat exchange unit, a plurality of spaced apart substantially parallel sheet metal walls having passageways therebetween; expansion and reinforcing ribs in said walls comprising integral doubled portions substantially perpendicular to said walls extending from one side to another of said walls in spaced apart relation, said ribs protruding into alternate passageways and providing partition and deflector means in said alternate passageways; closure means at the sides of the passageways into which the ribs project extending in the same general direction as the ribs; and other closure means at the sides of the other passageways positioned at approximately right angles to said ribs and to said first mentioned closure means.

3. In a heat exchange unit of the class described, a plurality of substantially rectangular substantially parallel sheet metal walls supported in spaced apart relation providing therebetween passageways; closure means provided at opposite edges of alternate pasageways; other closure means provided at opposite edges of the passageways between said first mentioned passageways, said first mentioned closure means and said last mentioned closure means being positioned along edges at substantially right angles to each other providing between said walls two sets of fluid passageways extending generally at right angles to each other; expansion and reinforcing ribs in said walls comprising integral doubled portions substantially perpendicular to said walls protruding into said passageways providing partition and deflector means in said passageways, said ribs extending in the same general direction as the closure means at the sides of the passageways in which said ribs are positioned.

4. In a heat exchange unit, a plurality of substantially parallel sheet metal walls spaced apart providing passageways therebetween; closure means at opposite edges of alternate passageways; other closure means at opposite edges of the passageways between said first mentioned passageways, said first mentioned closure means and said last mentioned closure means being positioned along edges at substantially right angles to each other; a cross bar movably supported at one side of said heat exchange unit, bar moving means connected with said cross bar; and a plurality of cleaner members on said cross bar extending into alternate passageways in relatively close proximity to said walls and movable reciprocably with said cross bar to clean said

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