US2979050A

US2979050A - Header assembly for space heater

Info

Publication number: US2979050A
Application number: US631525A
Authority: US
Inventors: George T Costello
Original assignee: NAT HEATER Co Inc
Current assignee: NAT HEATER Co Inc; NATIONAL HEATER COMPANY Inc
Priority date: 1956-12-31
Filing date: 1956-12-31
Publication date: 1961-04-11
Anticipated expiration: 1978-04-11

Description

April 11, 1961 G. T. COSTELLO HEADER ASSEMBLY FOR SPACE HEATER Filed Dec. 31. 1956 0 1 mM m m6 6 2 0 0% w; 4

' Zara! Unite States HEADER ASSElVIBLY FOR SPACE HEATER Filed Dec. '31, 1956, Ser. No. 631,525

6 Claims. (Cl. 126- 104) This invention relates to space heaters, and more particularly to a header assembly therefor.

In the space heater art, the combustion chamber and other parts thereof are not lined with refractory or in sulation material and rapid transfer of heat must be efiected through thin-walled metal members without raising the temperatures thereof to a point where the metal will become permanently distorted or melted. For this reason, the portions of the heater subjected to the more intense heat are constructed from stainless steel or other metals having good heat transfer and capable of withstanding high temperatures.

Where heat is directly and rapidly transferred through thin-shelled metal members, a greater amount of heat can be transferred per unit of area,and in a given time, than in the case of refractory or insulation-lined furnaces where the heat is transferred through secondary radiation elements.

In effecting direct heat transfer, however, the metallic parts of the furnace are subject to high temperatures which cause the parts to expand and contract in accordance with the temperature applied. Because the temperature is not always evenly raised throughout the entire structure, certain portions thereof will be caused to expand and contract at greater rates than others. For this reason, stresses and strains are set up if the parts of a space heater are all welded or otherwise rigidly secured together. Various means have been proposed in the prior art for permitting expansion or take-up in the supporting structure of such devices and the yielding parts generally have been permitted to slide on a support or to expand against a yieldable supporting wall when the above noted temperature difference takes place.

The present invention is concerned with permitting complete expansion and contraction in a simultaneous or difierential manner between the affected parts of a space heater without requiring any special suspension system and without requiring strains or distortion to be exerted on any of the supporting or structural parts.

It is, therefore, an important object of the present invention to provide a header assembly for a space heater in which the combustion chamber as well as exhaust flues can expand at the same, or differential, rates without distorting or straining the remaining structure of the space heater.

It is another object of the invention to provide a space heater structure in which the combustion chamber and exhaust flues can be rigidly secured at one end of the heater while the other ends of the hues and combustion chamber are received in a rigid header in such a manner as to communicate therewith in closely interfitting relation, yet permitting all of the members to expand and contract without creating strains in the equipment or without permitting any substantial escape of air or combustion gases into or out of the enclosed passageways.

Another object of the invention is to provide a special interconnection between the plate of a single header with a space heater combustion chamber and exhaust flues atent O thereof which will maintain the chamber and flues in proper functioning relation with the header and guide the elements in retained relation irrespective of the amount of heat applied within operational limits.

These and other objects and advantages of the invention will more fully appear from the following description, made in connection with the accompanying drawings, wherein like reference characters refer to the same parts throughout the several views and in which:

Figure 1 is a side elevation of a space heater unit embodying my invention, portions of the outer housing being cut away to show the particular area utilizing the invention and hidden portions being shown in dotted line structure; burner assemblies and chimney members further being omitted from the view;

Figure 2 is a partial end View in vertical section of the interconnection between the combustion header and the combustion chamber and exhaust flues taken on the line 2-2 of Figure l Figure 3 is an enlarged fragmentary view showing the interconnection in the header assembly of the combustion chamber and the header plate taken sectionally on the line 3-3 of Figure 1;

Figure 4 is an enlarged fragmentary view taken on the horizontal section 4-4 of Figure 1, and showing the interconnection between one of the exhaust flues and the header; and

Figure 5 is an enlarged fragmentary view similar to Figure 3, of an alternate form of the invention embodying a somewhat different interconnection between the combustion chamber and the exhaust header, hidden portions being indicated in dotted line.

With continued reference to the drawing, the space heater generally comprises a hollow base 19 within which are disposed a plurality of blower units 11 which bring in cool air and direct it upwardly against the combustion chamber which is designated generally at 12. The combustion chamber 12 has an opening 13 at its forward end which is adapted to receive a burner such as a gas or oil burner of conventional design and not shown in mounted relation. An exhaust header 14 overlies the inlet end of combustion chamber 12 and both are supported rigidly with respect to frame structure 15, as shown. 'The exhaust header 14 has an outlet 16 adapted to communicatewith a chimney for exhausting burnt gases into the atmosphere. A plurality of exhaust tubes or [flues 17 overlie the combustion chamber 12 in parallel relation one with the other and all the tubes and the combustion chamber are confined within an outer housing 18. A combustion chamber header 19 communicates with the combustion chamber 12 and with the exhaust tubes or flues 17 so as to cause the combustion gases to reverse their travel and return in overlying parallel relation with the travel of the gases within the combustion chamber 12. The combustion chamber header 19 may be provided with a damper 20 and one or more access ways .21, as shown. The lower portion 22 of the combustion chamber header 19 is rigidly supported on the base 10 and lies in fixed relation with the housing 18 and the exhaust header 14.

The present invention is particularly concerned with the header assembly indicated generally at 23 which includes the combustion chamber header 19 and portions of the tubes or flues. 17, as well \as the combustion chamber 12. Combustion chamber header 1h is provided with a plate 24 which faces inwardly and has a plurality of openings 25 which are adapted to receive the ends of combustion flues 17 and has an enlarged opening 26 for receiving the outlet end 27 of combustion chamber 12. All of the openings 25 and 26 are made to conform closely to the cross section of the respective tube and chamber 12 and supports the outlet end 27 of the combustion chamber with a marginal portion thereof extending outwardly beyond the plate 24 in the form of the invention illustrated in Figs. 1 and 3.

The combustion chamber 12 is of uniform cross section and constructed of thin-shelled metal material such as stainless steel and has adjacent the end 27 a shield member 30 secured thereto in close relation, the shield 3t} presenting an edge 31 which, in turn, defines a flangereceiving slot 32. In the form shown, the shield 30 is spaced in close parallel relation with the outer surface 29 of combustion chamber 12 by means of an interposed band 33 of a lesser width than shield 30 which is secured to the combustion chamber 12 with the shield 30 in overlying relation therewith, the band and shield members being Welded at 34 to the combustion chamber 12. With the combustion chamber 12 in normal mounted relation, as shown in Figs. 1 and 3, the space 32 is partly occupied with flange 28 and resilient packing material such as asbestos 35 may be interposed in the space between edges 36 of the flange 23 and the opposed edge 37 of the band 33.

In the openings 25, as shown in Figs. 2. and 4, the elongated exhaust tubes or flues 17 are received at their ends with a portion 38 extending past the plate 24 and swedged to a larger flared diameter to entrap each tube 17 against endwise displacement through plate 24. At the same time, an annular expanded rib 39 may be formed by passing a tool diametrically outward against the inner wall of each tube 17 closely adjacent the header wall 24. Rib 39 and swedged end 3% are spaced sufiiciently to permit longitudinal movement of each tube 17 with respect to header wall 24. The swedging operation may also serve to expand the tube 17 to close any clearance between the tube and the edge of opening 25. It is understood that a similar end connection may be made between each flue 17 and the exhaust header 14, if desired.

In practice, a high volume of burning gases are caused to traverse the length of the combustion chamber 12 and to heat the thin-walled structure thereof to temperatures high enough to make the combustion chamber glow a dull red heat. Obviously, the thin metal will expand lengthwise and it is a purpose of the invention to obviate strains in the remaining structure of the space heater during expansion and contraction of the combustion chamber and of the flues or tubes 17. As the combustion chamber grows in length during heating, it will merely slide with respect to flange 28 and the packing 35 will be compressed between the edges 37 on band 33 and 36 on flange 28. The shield 30 will slide in overlapping relation with the flange 28 and maintain but a slight clearance to minimize any passage of exhaust gases or air from the space inside of housing 18 to the combustion chamber housing 19 or vice versa.

The length of extending margin 27 is suificient to maintain the combustion chamber 12 at all times supported upon the flange 28 and the peripheral edge of opening 26.

Simultaneously with the application of heat to combustion chamber 12, the fines or tubes 17 will also be heated, but to a lesser degree. The simple swedged end margin 33 provides a shouldered end which will permit growth and shortening of the tube 17 without placing strain on the plate 2d. The elongation and shrinkage of each tube 17 is permitted through the opening 25 in header wall 24 while, at the same time, maintaining a close fit in the opening to prevent mixing of exhaust gases into the heated air. Conventional welded flue connections to the headers, I have found, can be completely eliminated. Where the ends of tubes 17 are welded or otherwise secured to the header 19, the plate 24 or some other portion of the spaced heater must yield under the influence of the change in length of the tubes. In the present invention, the tubes themselves are permitted to expand without placing such strains on the remainder of the space heater structure. Plate 24 on header 19 is thus permitted to maintain a fixed relation with respect to the space heater base and frame structure even when a differential temperature and elongation between the combustion chamber 12 and tubes 17 may occur. Each can grow independently of the others. In practice, it has been found desirable to place the entire combustion passageways under a slight vacuum so that such leakage as may exist between the plate openings 25 and 26 and the respective tubes 17 and combustion chamber 12 will permit a small amount of air to seep into the combustion gases rather than permit the combustion gases to seep outwardly into the air. 7

Another form of combustion chamber interconnection is shown in Fig. 5 wherein the header assembly is constructed so that the plate 24 is provided with a laterally extending flange 41 which is reversely bent at 41 to lie in closely spaced clearance therewith. in this case, the flange ill extends outwardly of the plate 24 rather than inwardly as in the first form. The space 42 is adapted to receive the marginal end 27 of the combustion chamber 12 and, here again, packing material 43 may be inserted in the remaining space 4-2 lying between the bent edge 44 and the outer edge 45 of the marginal end 27 of combustion chamber 12, as shown in Fig. 5.

As in the first form of the invention, the combustion chamber 12 is permitted to freely change in length. However, as shown in Fig. 5, the outermost edge 45 slips into the space 42 and compresses the packing 43. Upon contraction, the reverse movement takes places without placing strain upon the plate 24. The arrangement shown in Fig. 5 is such as to cooperate with the differential expansion and contraction of tube 17 in the same manner as previously described.

It may thus be seen that I have devised a simple and efficient header assembly which relieves all strains upon the various components of a space heater while permitting differential expansion and contraction irrespective of the temperatures applied to the components thereof.

It will, of course, be understood that various changes may be made in the form, details, arrangements and proportions of the parts without departing from the scope of my invention.

What I claim is:

1. In a space heater, a header assembly comprising, a supporting structure, an elongated horizontal combustion chamber constructed of uninsulated thin-shelled metal having high heat resistance, said chamber having an inlet end portion fixed to the supporting structure for introduction of combustible substances and an outlet at the opposite end thereof, a header fixed with respect to the supporting structure and inlet end of said chamber for receiving combustion gases from said combustion chamber, said header having a plate transverse to the longitudinal disposition of said chamber with an opening formed therethrough adapted to register with the outer margin of said thin-shelled combustion chamber and conformed substantially to the same cross section as that of the thin-shelled chamber, a flange extending normally outward along the peripheral length of said opening and adapted to support the horizontal combustion chamber marginally of the outlet end thereof, and a shield se cured about the periphery of said chamber adjacent the outlet margin of the combustion chamber and lying in close overlapping relation with said flange whereby said combustion chamber, during elongation and shortening thereof, under the influence of heating and cooling will slide with respect to said plate yet maintain close-fitting relation with said header.

2. In a space heater, a header assembly comprising, a supporting structure, an elongated horizontal combustion chamber constructed of uninsulated thin-shelled metal having high heat resistance, said chamber having an inlet end portion fixed to the supporting structure for combustible substances and an outlet at the opposite end thereof, a header fixed with respect to the supporting structure and the inlet end of said chamber for introduction of receiving combustion gases from said combustion chamber, said header having a plate transverse to the longitudinal disposition of said chamber with an opening formed therethrough adapted to register with the outer end of said thin-shelled combustion chamber and conformed substantially to the same cross section as that of the thin-shelled chamber, a flange extending normally outward along the peripheral length of said opening and adapted to support the horizontal combustion chamber marginally of the outlet end thereof, a band secured marginally inward of said combustion chamber for the peripheral length thereof, a shield of relatively greater width than said band secured thereagainst in overlapping relation with said flange whereby said combustion chamber during elongation and shortening thereof under the influence of heating and cooling will slide with respect to said plate, yet maintain close-fitting relation with said header.

3. The subject matter set forth in claim 2, wherein spaced clearance exists edgewise between said flange and said band and resilient packing is positioned underneath said shield and within said spaced clearance.

4. In a space heater, a header assembly comprising, a supporting structure, an elongated combustion chamber constructed of uninsulated thin-shelled metal having high heat resistance, said chamber having an inlet end portion fixed to the supporting structure for introduction of a combustible substance and an outlet at the opposite end thereof, a header fixed with respect to the supporting structure and the inlet end of said chamber for receiving and transmitting combustion gases from said combustion chamber, said header having a plate transverse to the longitudinal disposition of said chamber with an opening formed therethrough adapted to register with the outlet of said thin-shelled combustion chamber and conformed substantially to the same cross section as that of the thin-shelled chamber, slip joint means mounted between said opening and the outlet end of the combustion chamber, said plate further having a plurality of smaller spaced openings adjacent the first mentioned opening, and a plurality of exhaust flues each having one end fixed with respect to the supporting structure and the inlet end of said chamber and having its opposed end slidably projecting through a corresponding small opening in said header plate and swedged to larger diameter at a predetermined clearance with said plate within the header, whereby said combustion chamber and exhaust flues during elongation and shortening thereof under the influence of different rates of heating and cooling may slide independently with respect to said plate in its fixed relation to the supporting structure, yet maintain close-fitting relation with said header.

5. In a space heater, a header assembly comprising, a supporting structure, an elongated horizontal combustion chamber constructed of uninsulated thin-shelled metal having high heat resistance, said chamber having an inlet end portion fixed to the supporting structure for introduction of a combustible substance and an outlet at the opposite end thereof, a header fixed with respect to the Supporting structure and the inlet end of said chamber for receiving combustion gases from said combustion chamber, said header having a plate transverse to the longitudinal disposition of said chamber with an opening formed therethrough adapted to slidably receive the outlet end of said thin-shelled combustion chamber and conformed substantially to the same cross section as that of the thin-shelled chamber, a flange extending normally outward along the peripheral length of said opening and adapted to support said horizontal combustion chamber at the outlet end thereof, and a shield secured about the periphery of said chamber adjacent the outlet margin in close overlapping relation with said flange, the outer edge of said shield being recessed inwardly from the edge of the outlet end of said combustion chamber whereby said combustion chamber, during elongation and shortening thereof under the influence of heating and cooling, will slide reciprocally within said header with respect to said plate and supported thereby, yet will maintain closefitting relation with said header.

6. In a space heater, a header assembly comprising, a sup-porting structure, an elongated horizontal combustion chamber constructed of uninsulated thin-shelled metal having high heat resistance, said chamber having an inlet end portion fixed to the supporting structure for introduction of a combustible substance and an outlet at the opposite end thereof, a header fixed with respect to the supporting structure and the inlet end of said chamber for receiving and transmitting combustion gases from said combustion chamber, said header having a plate transverse to the longitudinal disposition of said chamber with an openingformed therethrough adapted to register with the outlet of said thin-shelled combustion chamber and conformed substantially to the same cross section as that of the thin-shelled member, a flange fixed peripherally of said opening and adapted to support the horizontal combustion chamber marginally of the outlet end thereof, the outlet end extending beyond the plane of said plate, a shield secured about the periphery of said chamber adjacent the outlet margin of the combustion chamber and lying in close overlapping relation with said flange, a plurality of apertures formed in spaced relation adjacent said opening, and a plurality of exhaust flues each having one end fixed with respect to the supporting structure and the inlet end of said chamber and having its opposed end slidably projecting through a corresponding aperture in said header plate and swedged to larger diameter at a predetermined clearance with said plate within the header, whereby said combustion chamber in its slidably supported relation on the flange and the exhaust flues in their swedged retention in said apertures during elongation and shortening thereof under the influence of different rates of heating and cooling may slide independently with respect to said plate in its fixed relation to the supporting structure yet maintaining close-fitting relation with said header.

References Cited in the file of this patent UNITED STATES PATENTS 35,541 Pond June 10, 1862 273,151 Randall Feb. 27, 1883 1,260,722 Shipman Mar. 26, 1918 1,389,408 Wilputte Aug. 30, 1921 1,644,180 Croan Oct. 4, 1927 1,936,003 White Nov. 21, 1933 2,353,606 Watts July 11, 1944 2,800,126 Costello et a1. July 23, 1957