US2284769A - Heat exchanger - Google Patents

Description

' INVE TOR MW" /bLV H. M. ROGERS HEAT EXCHANGER Filed Aug. s, i940 June 2, 1942.

Patented June 2, 1942 UNITED STATESPATENT OFFICE HEAT EXCHAN GER Harry M. Rogers, Dayton, Ohio, assignor to Chrysler Corporation, Detroit, Mich., a corporation of Delaware Application August 3, 1940, Serial No. 350,337

3 Claims.

heat between .the flue gases and the warm air being heated by the furnace. To this end, the furnace comprises a heat exchanger having a bailie therein and so arranged as to direct flue gases in one direction through a portion of the heat exchanger and around an end of the baffle so as to pass in an opposite direction out of the heat exchanger. The principal object of the present invention is accomplished by permitting small quantities of the flue gases to pass around the edges of the baflie while the main portion thereof passes around the end, the small quan,- tities of flue gases so passed around the edges Y greatly aiding the transfer of heat by increasing the temperature of some portions of the heat exchanger.

A second object of the invention is soto arrange a baiiied heat exchanger as to prevent the,

trapping of any unburned or `partially burned gases between burner operating periods which might flash or explode in the heat exchanger with resulting rumbles and reverberations, if not damaging explosions. Such flash explosions of small Aquantities of unburned gases are usually yharmless but the noise is annoying and sometimes frightening. Proper adjustment of the burner would prevent the occurrence of such flash ex.

plosions, but the present invention is designed to prevent their occurrence in spite of improper burner adjustment.

The objects and advantages of the present invention should be more readily apparentto those skilled in the art from a study of the following specification and accompanying drawing wherein like numerals refer toV like parts throughout.

In the drawing, Fig. 1 is a front elevational View of a furnace constructed in accordance with my invention;

Fig.. 2 is a side elevational View of the furnace;

Fig. 3 is a partial section on an enlarged scale of the lower end of abaiile and the portions ofi the side walls of the heat exchanger Yadjacent thereto; and,

Fig. 4 is a cross-section taken along line 4-4 of Fig. 2. A

In the drawing, the numeral I0 refers to a furnace jacket in which is enclosed a welded firebox and heat exchanger construction including the firebox II in which the burner I2 is located, lateral flues I3 extending from the front, upper corners of the rebox into laterally spaced heat exchangers I4, and a lateral triangular connecting flue I5 which leads into the smoke stack connector I6 from the upper, rear corners of the.

heat exchangers. The hot flue gases passing upward from the burner I2 divide and pass through the passages I3 into the upper, front corners of the heat exchangers I4 where they are directed downwardly by rvertically extending baffles 2li. After passing around the lower ends ofthe baffles the gases pass upward into the triangular connecting flue I5 and out through the stack I6. The air to be warmed is admitted to theinterior of the jacket through a duct connector 2| and drawn through a filter 22 by centrifugal blowers 23 driven by motor 24. The blowers direct the air upwardly through the spaces between the jacket Ill, the heat exchangers I4, and the furnace rebox II, and also through the'inclined crown sheet passage 26 extending over the hottest portion of the flame area. The warmed air is forced outward through the duct connector 21 which is adapted to be connected to the ducts leading to the space to be heated. Other types of furnaces having heat exchangers in which baffles change the direction of travel of the flue gases may have my invention incorporated therein, the above construction being one of many which wouldfind the invention'of utility.

The improvement comprising my present invention is so to arrange the baflie 20 in the heat exchanger I4 as to provide for the escape of small quantities of hot flue gases at the upper end of the bailie, preferably entirely around the edges thereof, or at least at certain portions thereof as in the area between the passages I3 and the triangular connecting flue I5'so as to prevent the trapping of any gases in the upper portions of the heat exchanger. Preferably, also, theY passages around the edges of the baflies extend throughout the length of the baffles as shown in the drawing, v

so' as to provide for intimate contact of moving streams of hot gases against the side walls of the heat exchangers adjacent the edges of the baiiies `2iI so as to heat the surfaces of the heat exchangexchangers tends to be heated to the same extent as the air which passes through the crown sheet passage 26 adjacent the triangular ilue I5. Also, any tendency of the sheets forming the side walls of the heat exchangers to buckle or warp is lessened since the surfaces thereof are heated more uniformly throughout their areas, and the welds between the sheets do not tend to crack due to uneven expansion and contraction thereof.

As seen in Figs. 3 and 4 the bafes 2U are preferably mounted upon a plurality of rods 3|) as by means of welding the same to the surface of the baffle. The ends of the rods 30 are passed through openings in the side walls of the heat exchangers |l and welded thereto to form a rigidly braced structure having the edges of the bailies properly spaced from the inner surfaces of the heat exchangers.

The ease of assembly of this construction is clearly shown in Fig. 4 wherein it is shown that the outer wall 3| of the heat exchanger ld may be formed as a continuous sheet having its edges notched and bent outward to form the end and side Walls of the heat exchanger, the edges of the walls being flanged outward so as to enable the sameto be welded to the flat sheet forming the inner wall 32 of the heat exchanger. The outer wal1 3| is formed and shaped, then the baffie 2 is placed in position and welded to the wall 3| and then the rods 30 welded to the wall 3|. Thereafter the wall 32 is welded to the rods 3D and to the flanges of the walls extending from sheet 3| to form the complete heat exchanger which may then be united to the rebox by welding the connecting ilues i3 and I5 thereto.

Having. described the preferred form of my invention, it should be apparent to those skilled in the art that the same permits of modications in detail and arrangement. All such modications as come within the scope of the following claims are considered to be a part of my invention.

I claim:

1. In a war-m air furnace, a relatively narrow heat exchanger having an inlet and an outlet, both of which are located in the upper part thereof, and side walls of relatively large area over which air passes to be heated by thermal exchange with the flue gases therein, a plurality of tie-rods extending between said side walls and having their ends integrally united thereto in order rigidly to brace said side walls, and a substantially vertical baie integrally united to said tie-rods and extending from the top of said heat exchanger to a point spaced a substantial distance from the bottom thereof so as substantially to block direct passage of the flue gases through the heat exchanger from said inlet to said outlet and to cause the major part of the flue gases to flow through said heat exchanger around the lower e-nd of said baiiie while passing from said inlet to said outlet, a side edge of said baiile being slightly spaced from the adjacent side wall whereby to permit direct passage of a small quantity of flue gases from said inlet to said outlet in order to prevent trapping of unburned gases in the upper part of said heat exchanger and in order to heat said side walls more uniformly when the furnace is in operation.

2. In a warm air furnace, a relatively narrow heat exchanger having an inlet and an outlet, both of which are located in the upper part thereof, and side walls of relatively large area over which air passes to be heated by thermal exi change with the flue gases the-rein, a plurality of tie-rods, extending between said side walls and having their ends integrally united thereto in order rigidly to brace said side walls, and a substantially vertical baile integrally united to said tierods and extending from the top of said heat exchanger to a point spaced a substantial distance from the bottom thereof so as substantially to block direct passage of the flue gases through the heat exchanger from said inlet to said outlet and to cause the major part of the flue gases to flow through said heat exchanger around the lower end of said bafe while passing from said inlet to said outlet, the side edges of said baffle being slightly spaced from said side walls whereby to permit direct passage of a small quantity of ue gases from said inlet to said outlet in order to prevent trapping of unburned gases in the upper part of said heat exchanger and in order to heat said side walls more uniformly when the furnace is in operation.

3. In a warm air furnace, a relatively narrow heat exchanger having an inlet and an outlet, both of which are located in the upper part thereof, and side walls of relatively large area over which air passes to be heated by thermal exchange with the ue gases therein, a plurality of tie-rods vextending between said side walls and having their ends integrally united thereto in order rigidly to brace said side walls, and a substantially vertical baiiie integrally united to said tie-rods and extending from the top of sai-d heat exchanger to a point spaced a substantial distance from the bottom thereof so as substantially to block direct passage of the flue gases through the heat exchanger from said inlet to said outlet and tc cause the major part of the ilue gases to flow through said heat exchanger around the lower end of said baffle while passing from said inlet to said outlet, the side edges and upper edge of said bailie being slightly spaced from said side walls and the top of said heat ex-I changer, respectively, whereby to permit direct passage of a small quantity of flue gases from said inlet to said outlet in order to prevent trapping of unburned gases in the upper part of said heat exchanger and in order to heat said side walls more uniformly when the furnace is in operation.

HARRY M. ROGERS.

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