US3058457A

US3058457A - Heat exchange assemblies for hot air furnace

Info

Publication number: US3058457A
Application number: US761544A
Authority: US
Inventors: George H Fiedler
Original assignee: Hupp Corp
Current assignee: Hupp Corp
Priority date: 1958-09-17
Filing date: 1958-09-17
Publication date: 1962-10-16
Anticipated expiration: 1979-10-16

Description

Oct. 16, 1962 G. H. FIEDLER HEAT EXCHANGE ASSEMBLIES FOR HOT AIR FURNACE Filed Sept. 17, 1958 2 Sheets-Sheet 1 INVENTOR GEORGE H. F/EoLER KM, W Z M Oct. 16, 1962 cs. H. FIEDLER 3,058,457

HEAT EXCHANGE ASSEMBLIES FOR HOT AIR FURNACE Filed Sept. 17, 1958 2 Sheets-Sheet 2 1- 7- 5 INVENTOR A GEO/26f H. F/EDLER f x 70 n 72 3-J .'4 74' 5 55 7&( M 22 ZATTORNEYfi 3,058,457 HEAT EXCHANGE ASSEMBLIES FOR HOT AIR FURNAEE George H. Fiedler, Euclid, Ghio, assignor to Hupp Corporation, Cleveland, Ohio, a corporation of Virginia Filed Sept. 17, 1958, Ser. No. 761,544 1 Claim. (Cl. 126-91) This invention relates to a novel heat exchanger for use with gas tired burners.

A principal object of the present invention is to provide a novel heat exchanger which is so arranged as to be mounted vertically in a side-by-side relationship with adjacent heat exchangers. In addition to providing good heating efliciency of the room air directed over the outer surfaces of the heat exchangers, the novel heat exchangers are lightweight, rigid, free from buckling and inexpensive to manufacture.

These and other objects of the invention will become more fully apparent from the claim, and from the description when considered in conjunction with the appended drawings wherein:

FIGURE 1 is a side elevation view in section of the furnace incorporating the heat exchangers of the present invention;

FIGURE 2 is a plan view of one stamping of the heat exchanger as it is received from the forming die;

FIGURE 3 is an end elevation view in section of the heat exchanger stamping taken along line 3-3 of FIG- URE 2;

FIGURE 4 is an end elevation view in section of the heat exchanger stamping taken along line 4-4 of FIG- URE 2; and

FIGURE 5 is a partial section taken along line 55 of FIGURE 2 showing the manner by which the heat exchanger members are secured together.

Referring now to FIGURE 1 in the drawings, the furnace of the present invention is provided with a front upper side wall panel which contains air admission apertures, which are preferably perforations, and a lower solid wall panel 12 which are both removable to provide access to the interior of the furnace from the front. The side walls as well as the rear wall 16 are made of aluminized steel. The air flow pattern for the warm air heating system is from the bottom of the furnace upwardly through filter 18, through blower 20 which is driven by electric motor 22, and upwardly around the outer surfaces of heat exchangers one of which is shown at 24 through duct opening 28 at the top of the furnace.

In front of the heat exchanger members 24 is an interior front panel 38 which as best shown in FIGURE 1 is supported between the upper side flange 120 on burner box 40 and the lower side flange 122 on flue collection box 42. Separate burner elements 44 are provided for each of the respective heat exchanger members 24.

Each heat exchanger member comprises a pair of substantially identical stampings such as that shown generally in FIGURE 2. A peripheral flat edge 60 is provided for securing two stampings together in a face-toface relationship so that the lower portion along supporting ribs or embossments 62 will provide a burner receiving chamber. Above ribs 62, four horizontally directed reinforcing ribs or

embossments

63, 64, 65 and 66 are provided. As is most clearly shown in FIGURE 5, embossments 6366 extend outwardly to provide an extended surface area to be exposed to the room air which passes upwardly across the outer surface of the heat exchanger members.

At the upper end of each of the heat exchanger stampings a semicylindrical section 70 is provided so that when the two stampings are placed together, the heat exchanger member will have a substantially cylindrical up- Patented Get. 16, 1962 ice per flue collection chamber for connection to flue box 42. The stamping as shown in FIGURE 2 is formed with an enclosed rear wall 72 for the cylindrical upper flue collection chamber and also with an enclosed front wall 74 which is subsequently removed as will be explained below. In the spaces between horizontal embossments 63-66 and between embossment 66 and cylindrical wall section 70, the flow of combustion products is restricted by the narrow passageway along walls 76 as shown in FIGURE 4. This passageway in a preferred embodiment is very narrow, being only about /2 inch between the two stampings.

The heat exchange section members 24 are then run through stamping presses which cut off the front upper portion containing front wall 74 starting at the upper end along edge 80, forwardly along edge 82, downwardly along edge 84, rearwardly along edge 86, downwardly along edge 88 and diagonally along edge 90 to thereby provide a front open end 92 which connects the flue collection chambers defined by cylindrical walls 70 with flue collection box 42. Referring again to FIGURE 2, the forward lower end of the right side heat exchanger stamping is cut along

edges

94, 96, 98, 100, 102 and 104 to provide an open section which fits onto the top and rear surfaces of burner box 40. No cuts are made on the rear side of the stamping which corresponds with the right-hand side of the drawing in FIGURE 2 for the right side stamping.

To provide the left side heat exchanger stamping, the cutting press may be provided with complementary dies which are cut at the top of the stamping along

edges

106, 107, 108, 109, 110, 111 and 112, and at the bottom of the stamping along

edges

113, 114, 115, 116, 117 and 119. No cuts are made on the rear side of the stamping which corresponds with the left-hand side of the drawing in FIGURE 2 for the left side stamping.

After the heat exchanger stampings are cut into the desired shape, opposing stampings are placed together face to face and a substantially continuous weld is provided around flanges 60 so as to provide a seal which prevents extensive escape of combustion products from the interior of the heat exchanger members 24. Spot welds are provided at a sufficient number of dimples 118 to prevent popping and buckling of the members as the heat exchanger temperature increases or decreases.

As is apparent from the foregoing, only one die for each of the right side and left side stampings of the heat exchangers 24 is necessary. The die includes horizontal embossments 6366 and dimples 118 which are so positioned that each of the dimples in the heat exchanger stampings meets to be welded together. Dimples 118 and the pattern thereof in welded secure-ment to each other provide a three-fold function of preventing oilcanning of the sides of the exchanger under heat and pressure stresses, collectively with the embossments of forming alternate points of restriction and expansion for the combustion products, and of lengthening the time of travel of the combustion products through the heat exchanger by restricting the volume and velocity of the flow of combustion products thereby aiding the efficiency of the exchange of heat. The resulting tortuous flow pattern compelling the combustion products to remain in contact with the metal surface of the heat exchanger walls obviates the necessity of resorting to separate directional or restrictive baflles at the top of the flues and the consequent added material necessary when employing such baflles as was conventional practice heretofore.

In assembly, the heat exchanger stampings are first assembled into complete heat exchanger members 24 to be available for use in furnaces of a variety of sizes. For a small residential furnace of 75,000 Btu output, 3 heat exchanger members are used. In 150,000 Btu. furnaces,

6 heat exchanger members are used. In intermediate furnace sizes, an intermediate number of heat exchangers are used.

Burner box 40 is provided with a front peripheral flange 120 which is mounted to be in substantial alignment with the front flange 122 on flue collection box 42 as shown in FIGURE 1. Upper surface 124 of burner box 40 is provided with a series of semicircular openings having edges 126 for receiving the forward cut-out surfaces along

edges

94, 96 and 98 of the heat exchanger stampings shown in FIGURE 2. In rear wall 128 of burner box 40, a series of vertically directed openings having semicircular bottom edges are provided for receiving the lower surface 102 in front of edge 104 on flange 60 of the heat exchanger members.

Bracket 132 is provided to be suitably secured to the lower rear portion of the heat exchangers 24 and to be supported on frame 122 of the furnace housing as shown in FIGURE 1.

For the assembly of a specific sized furnace, burner box 40 and flue collection box 42 are selected which have the desired number of openings for receiving a corresponding number of heat exchanger members. The lower rear surfaces of heat exchanger members 24 are connected to be supported in bracket 120 and the unit is then ready for assembly into the furnace frame. After the furnace assembly is completed, burners 44 may be readily inserted into the heat exchangers with bosses supported in the grooves of brackets 56 on the inner walls of the heat exchanger members. Suitable space is provided to insert the burners over the gas manifold 138 and through burner box 40 and the fuel inlet end of gas burner 44 is supported in a conventional manner on a gas manifold.

The burner support provides an arrangement whereby the burners may be pulled out easily for service and may be shipped in place without excessive wired-down provisions for transportation.

At the top of the furnace, there is further provided flue :box 42 which connects all of the heat exchanger members to flue 140 which is adjacent front wall of the furnace. The forward end 84 of flue collection cylinders 92 of each heat exchanger is secured as by welding to the rear panel surface of flue collection box 42. Flue pipe 140 is supported on plate 142 which is suitably secured to flange 122 around flue box 42 and to the side walls of the furnace. Flue plate 142 has a front member 144 which extends downwardly along the perforated front panel 10 and contains an inwardly directed lip 146.

Battle 1 48 is positioned directly below the opening of flue 140 and secured to the furnace side walls in an angular position so as to also extend in front of the cylindrical flue chambers 92 in each of the 'heat exchangers. Thus combustion products passing through flue chambers 92 are deflected downwardly by the lower surface of baflle plate 148 and then upwardly between lip 146 and plate 148 to flue 140. A small space is provided above the upper end 149 of bafile plate 148 and flue plate 142 whereby some direct flow of combustion products to line 140 is permitted. The perforations in front panel 10 in conjunction With the end of lip 146 and baflie plate 148 in front of flue 140 provide a direct air flow path up the chimney, and also prevent any downdraft from passing through the heat exchangers and extinguishing the flame.

Beneath baffle 148 is a further b-afile plate 150 which extends from front perforated wall 10 back to flange 122 on the lower surface of flue box 42 and is secured to the furnace side walls. Beneath baflle plate 150 air is free to pass through the perforations in front panel 10 to enter through the burner box 40 inside the heat exchange members 24 and mix with the combustion products.

The air to be heated, on the other hand, all enters through filter 18 which is in the lower portion of the furnace beneath the heat exchangers and is forced upwardly by blower 20 across the outside surfaces of the heat exchanger members 24 and around the outside of cylindrical walls of the flue collection chambers of the heat exchangers to pass through the warm air duct opening 28 at the top of the furnace.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claim rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claim are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

In a furnace of the type having separate air flow paths for combustion products and for air to be heated thereby, heat exchanger means comprising a pair of upright mem bers of sheet metal of substantially uniform thickness formed from the same die secured together around the periphery thereof, said members having their facing walls spaced apart at their lower end to form a chamber for receiving an elongated burner element and at an upper end to form a flue outlet chamber, the facing walls of said members in the space between said chambers being positioned closely together to form a relatively narrow passage for said combustion products and containing a plurality of spaced, outwardly projecting horizontal, nonintersecting embossments, the embossments of one memher being directly opposite the embossments of the other member, said embossments on each member being separated by substantially flat portions of said facing walls, inwardly projecting dimples in each of said fiat portions along the length thereof between adjacent embossments, the dimples in each flat portion being arranged in staggered relation to the dimples in a next adjacent flat portion, said dimples of one member being secured to the corresponding dimples of the other member to prevent separation of said members and to provide restriction to the flow of combustion products, said embossments serving as means for reinforcing said members to reduce buckling noise and enhance the heat exchange between combustion products and air outside of said members to be heated.

References Cited in the file of this patent UNITED STATES PATENTS 2,292,180 Tuck Aug. 4, 1942 2,464,473 Wessel Mar. 15, 1949 2,594,608 Cartter Apr. 29, 1952 2,613,920 Flint Oct. 14, 1952 2,658,504 Jaye et al. Nov. 10, 1953 2,808,047 Jaye et al Oct. 1, 1957 2,866,449 Baeza Dec. 30, 1958