Feb. 7, 1967 J. \NlTTEN, JR 3,392,795

HEAT EXCHANGER F led epfl- 21, 1964 2 Sheets-Sheet l INVENTOR.

Wilson J. Wi'fren,Jr.

ATTORNEY 3957 w. J. WITTEN, JR 1 HEAT EXCHANGER Filed ep 21, 1964 2 Sheets-5heet 2 I N V E N Wilson 1W Jr.

ATTORNEY United States Patent Ofiice mamas eateaiea rep. 7, rear 3,3ti2,705 HEAT EXCHANGER Wilson J. Witten, Jr., Louisvilie, Ky., assignor to American Radiator & Standard Sanitary Corporation, New York, N.Y., a corporation of Beiaware Filed Sept. 21, 1964, Ser. No. 397,747 11 Claims. ((11. 165-176) This invention pertains to heat exchangers and more particularly to heat exchangers for heating systems employing compact high temperature burners.

In closed hot water heating systems, heat is generated in a restricted area and transferred through the agency of hot water or the like to remote regions which are to be heated. Generally, in the restricted area there is a fuel burner which generates the heat. Adjacent the fuel burner there is a heat exchanger, a device which absorbs the generated heat and transfers it to a circulating fluid, usually water. The water is piped between radiators and the like and the heat exchanger. In this way, the heat generated by the fuel burner is transferred to a region such as a room which is to be heated. The time required to heat a region is dependent on the quantity of heat transferred to the region. The quantity of heat transferred depends on a number of factors which include the rate of heat generation by the fuel burner, the temperature in the region of the fuel burner and the efficiency of the heat exchanger.

There have recently become available surface combustion burners which by employing heat resistant porous fabrics which because of their large compact combustion sites produce heat with greater efliciency, at higher temperature and at faster rates. Such a burner has been described in the copending application for Burner Apparatus, Ser. No. 427,325, filed January 22, 1965 and assigned to the same assignee.

However, when such burners are employed they create problems with respect to the associated heat exchanger. In particular, the small size and rapid heat generation of the burner demand that the heat exchanger efliciently and rapidly transfer heat to the circulating fluid. Furthermore, the great range of temperatures that the heat exchanger is subjected to When the burner starts and stops operating causes appreciable mechanical changes in the heat exchanger. Accordingly, when using conventional heat exchangers and their usual supporting means there arises the possibility of creating internal stresses which may damage the heat exchanger.

It is therefore, an object of the invention to provide an improved heat exchanger.

It is another object of the invention to provide an improved heat exchanger which etficiently transfers heat from a compact fuel burner.

It is a further object of the invention to provide an improved heat exchanger which is relatively free from stresses in spite of the fact the heat exchanger may be subject to very large fluctuations in temperature.

It is another object of the invention to provide an improved heat exchanger for use with surface combustion type burners.

It is still a further object of the invention to provide a compact, highly eflicient heat exchanger which is easily fabricated and relatively inexpensive.

Briefly, the invention contemplates a heat exchanger which comprises a main header, a floating head and tubular conduits interconnecting the main and floating return header. The main header includes a chamber which is divided into an inlet region and an outlet region. An inlet conduit means is provided to feed fluid to the inlet region; and an outlet conduit means removes fluid from the outlet region. The floating return header includes a chamber. At least one tubular conduit connects the inlet region of the chamber of the main header to the chamber of the floating return header; and at least another tubular conduit connects the chamber of the floating return header to the outlet region of the chamber of the main header.

Accordingly, fluid can flow from the inlet conduit means, via the inlet region of the chamber of the main header through one tubular conduit to the chamber of the floating return header. The fluid then flows via another tubular conduit and the outlet region of the chamber of the main header to the outlet conduit means.

It should be noted that the tubular conduits provide, in addition to the fluid flow connections between the headers, the sole mechanical support for the floating return header.

It should also be noted that when a fuel burner is positioned between the tubular conduits the circulating fluid passes twice through the region where heat is generated.

Other objects, features and advantages of the inven tion will be apparent from the following detailed description of the invention when read with the accompanying drawings, which show by way of example and not limitation, the now preferred embodiment of the invention.

In the drawings:

FIGURE 1 is a side elevational view, partially in section, of a heat exchanger including a main header, a floating return header and a plurality of tubular conduits connecting the headers in accordance with the invention;

FIGURE 2 is an inside elevational view, partially in section, of the main header of the heat exchanger of FIGURE 1;

FIGURE 3 is an inside elevational view of the floating return header of the heat exchanger of FIGURE 1; and

FIGURE 4 is a cross-sectional view of the floating return header taken along the line 44 of FIGURE 3.

Referring to FIGURE 1 a heat exchanger 10, in accordance with the invention is shown comprising a main header 12, a floating return header 14 and a plurality of finned tubular conduits 16 which interconnect the headers. It should be noted that only a few of the fins 18 are shown. However, it should be realized that fins 13 are distributed uniformly along the tubular conduits 16. Tubular conduits 16 are mutually parallel and are in a hollow cylindrical array. The fins 18 of adjacent tubular conduits 16 abut each other. Within the hollow cylindrical array of tubular conduits 16 is preferably disposed an elongated cylindrical surface combustion burner (not shown) of the type described in the above cited application.

Main header 12 (see also FIGURE 2) includes a toroidal chamber housing 20 preferably of cast brass. Diametrally opposite partitions 22 and 24 divide the toroidal chamber defined by housing 20 into an inlet region 20A and an outlet region 20B. An inlet means 26 extends substantially tangentially from the inlet region 20A. Inlet means 26 is connected to an inlet conduit means 30. An outlet means 28 also tangentially extends from the outlet region 20B. Outlet conduit means 32 is connected to outlet means 28. A plurality of openings 34 are uniformly distributed along a circle on the inner face of toroidal chamber housing 20. Each of the openings 34 accommodates an end 17 of one of the tubular conduits 16 (see in particular FIGURE 1). End 17 is brazed to the defining wall of opening 34. Half of the openings i.e., those to the left of a diameter including partitions 22 and 24 in FIGURE 1 are in communication with the outlet region 20B of the toroidal chamber.

The floating return header 14 includes a housing 36 of cast brass which defines a freely communicating chamber 38. The inner face of housing 36 is provided with a plurality of openings 40. Each of the openings 40 3 accommodates an end 19 (FIGURE 1) of one of the tubular conduits 16. Ends 19 of the tubular conduits 16 are brazed to the defining walls of openings 40.

-Tubular conduits 16 are of copper tubing with extended fins 18. Accordingly, the conduits are unitary structures with fins integral therewith and laterally extending therefrom.

When assembled in a heating system, heat exchanger 19 is only supported from main header 12. Floating return header 14 is supported only through the agency of tubular conduits 16.

During operation, fluid enters the heat exchanger from inlet conduit 30 (FIGURE 2) and passes through inlet means 26 to the inlet region 20A of the toroidal chamber. The fluid leaves from the openings 34 in the inlet region 20A and flows via the associated tubular conduits 16 (FIGURE 1) to floating return header 14. After freely circulating through the chamber of floating return header 14, the fluid flows through the other half of the tubular conduits 16 to the openings 34 in the outlet region 20B (FIGURE 2). The fluid flows from outlet region 20B via outlet means 28 to outlet conduit means 32.

Therefore, in a complete system which includes radiators and a burner, cooled water from the radiators is fed to inlet conduit means 30, heated in heat exchanger 10 by moving twice past the burner disposed within the cylindrical cavity defined by the tubular conduits 16, and is fed from outlet conduit means 32 to the radiators.

There has thus been shown an improved heat exchanger which by employing a floating return header supported by only tubular conduits is free from mechanical stresses resulting from extreme temperature changes. Furthermore, by employing a main header connected to la. floating return header by a plurality of finned tubular conduits whose fins mutually abut, an extremely compact and efficient heat exchanger is obtained. In a specific example, there is obtained a heat exchanger having a volume less than one third of a cubic foot which is used in a system delivering 75,000 B.t.u.s per hour.

While only one embodiment of the invention has been shown and described in detail there will now be obvious to those skilled in the art many modifications and variations which satisfy many or all of the objects of the invention. However, these modifications and variations 'will not depart from the spirit of the invention as defined by the appended claims.

What is claimed is:

1. A heat exchanger comprising: a main header including a housing defining a chamber, means for dividing said chamber into an inlet region and an outlet region, inlet conduit means for feeding fluid to said inlet region, outlet conduit means for removing fluid from said outlet region; a floating return header including a housing defining a chamber remote from said main header; :1 plurality of horizontally disposed, spaced tubular conduits, at least one of said tubular conduits connecting the inlet region of the chamber of said main header to the chamber of said floating return header, at least one other of said tubular conduits connecting the outlet region of the chamber of said main header to the chamber of said floating return header; said tubular conduits defining a substantially hollow cylinder and providing, in addition to the fluid flow connections between said headers, the sole mechanical support for said floating return header.

2. A heat exchanger comprising: a main header including a housing defining a chamber, means for dividing said chamber into an inlet region and an outlet region, inlet conduit means for feeding fluid to said inlet region, outlet conduit means for removing fluid from said outlet region; a floating return header including a housing defining a chamber remote from said main header; a plurality of horizontally disposed, spaced tubular conduits, each of said tubular conduits including a plurality of laterally extending fin members integral therewith, at least one of said tubular conduits connecting the inlet region of the chamber of said main header to the chamber of said floating return header, at least one other of said tubular conduits connecting the outlet region of the chamber of said main header to the chamber of said floating return header; said tubular conduits defining a substantially hollow cylinder and providing, in addition to the fluid flow connections between said headers, the sole mechanical support for said floating return header.

3. A heat exchanger comprising: a main header including a housing defining a toroidal shaped chamber, first and second partitions in a diametral plane of said toroidal shaped chamber for dividing said chamber into an inlet region :and an outlet region, inlet conduit means for feeding fluid to said inlet region, outlet conduit means for removing fluid from said outlet region; a floating return header including a housing defining a chamber remote from said main header; a plurality of horizontally disposed, spaced tubular conduits, at least one of said tubular conduits connecting the inlet region of the chamber of said main header to the chamber of said floating return header, at least one other of said tubular conduits connecting the outlet region of the chamber of said main header to the chamber of said floating return header; said tubular conduits defining a substantially hollow cylinder and providing, in addition to the fluid flow connections between said headers, the sole mechanical support for said floating return header.

4. A heat exchanger comprising: a main header including a housing defining a toroidal shaped chamber, means for dividing said chamber into an inlet region and an outlet region, inlet conduit means tangentially extending from said toroidal shaped chamber adjacent said inlet region for feeding fluid thereto, outlet conduit means tangentially extending from said toroidal shaped chamber adjacent said outlet region for removing fluid therefrom; :a floating return header including a chamber remote from said main header; a plurality of horizontally disposed, spaced tubular conduits, at least one of said tubular conduits connecting the inlet region of the chamber of said main header to the chamber of said floating return header, at least one other of said tubular conduits connecting the outlet region of the chamber of said main header to the chamber of said floating return header; said tubular conduits defining a substantially hollow cylinder and providing, in addition to the fluid flow connections between said headers, the sole mechanical support for said floating return header and said inlet and outlet conduit means providing the sole mechanical support site for said heat exchanger.

5. A heat exchanger comprising: a main header including a housing defining a toroidal shaped chamber, first and second partitions in a diametral plane of said toroidal shaped chamber for dividing said chamber into an inlet region and an outlet region, inlet conduit means tangentially extending from said toroidal shaped cham ber adjacent said inlet region for feeding fluid thereto, outlet conduit means tangentially extending from said toroidal shaped chamber adjacent said outlet region for removing fluid therefrom; a floating return header including a housing defining a chamber remote from said main header; a plurality of horizontally disposed, spaced tubular conduits, at least one of said tubular conduits connecting the inlet region of the chamber of said main header to the chamber of said floating return header, at least one other of said tubular conduits connecting the outlet region of the chamber of said main header to the chamber of said floating return header; said tubular conduits defining a substantially hollow cylinder :and providing, in addition to the fluid flow connections between said headers, the sole mechanical support for said floating return header.

6. A heat exchanger comprising: a main header including a housing defining a toroidal shaped chamber, first and second partitions in a diametral plane of said toroidal shaped chamber for dividing said chamber into an inlet region and an outlet region, inlet conduit means tangentially extending from aid toroidal shaped chamber adjacent said inlet region for feeding fluid thereto, outlet conduit means tangentially extending from said toroidal shaped chamber adjacent said outlet region for removing fluid therefrom; a floating return header including a housing defining a chamber remote from said main header; a plurality of horizontally disposed, spaced tubular conduits, each of said tubular conduits including a plurality of laterally extending fin members integral therewith, at least one of said tubular conduits connecting the inlet region of the chamber of said main header to the chamber of said floating return header, at least one other of said tubular conduits connecting the outlet region of the chamber of said main header to the chamber of said floating return header; said tubular conduits defining a substantially hollow cylinder and providing, in addition to the fluid flow connections between said headers, the sole mechanical support for said floating return header.

7. A heat exchanger for use with a cylindrical burner comprising: a main header, said main header including a housing defining a toroidal chamber, first and second partitions in radial planes within said toroidal chamber for dividing the latter into a fluid inlet region and a fluid outlet region, a fluid inlet in said fluid inlet region adapted to be connected to a fluid input conduit, a fluid outlet in said fluid outlet region adapted to be connected to a fluid output conduit, said toroidal chamber housing being provided with a plurality of openings in a plane perpendicular to the axis thereof; a floating return header remote from said main header, said floating return header including a housing defining a freely communicating chamber, said freely communicating chamber housing being provided with a plurality of openings respectively facing the openings in the toroidal chamber of said main header; and a plurality of tubular conduit defining a substantially hollow cylinder, each of said tubular conduits connecting a pair of oppositely faced openings, one of the openings of said pair being in said toroidal chamber housing and the other of the openings of said pair being in said freely communicating chamber housing whereby fluid entering said fluid inlet region from said fluid input conduit via said fluid inlet flows via at least one of said tubular conduits to said freely communicating chamber and from the latter via at least another of said tubular conduits, said fluid outlet region and said fluid outlet to said fluid output conduit; said heat exchanger being supported only at said main header so that said heat exchanger can unconstrainediy change mechanical dimensions in response to temperature changes.

8. A heat exchanger for use with a cylindrical burner comprising: a main header, said main header including a housing defining a toroidal chamber, first and second partitions in radial planes within said toroidal chamber for dividing the latter into a fluid inlet region and a fluid outlet region, a fluid inlet in said fluid inlet region adapted to be connected to a fluid input conduit, said fluid inlet extending tangentially from said toroidal chamber, a fluid outlet in said fluid outlet region adapted to be connected to a fluid output conduit, said fluid output extending tangentially from said toroidal chamber, said toroidal chamber housing being provided with a plurality of openings in a plane perpendicular to the axis thereof; a floating return header remote from said main header, said floating return header including a housing defining a freely communicating chamber, said freely communicating chamber housing being provided with a plurality of openings respectively facing the openings in the toroidal chamber of said main header; and a plurality of tubular conduits, each of said tubular conduits defining a substantially hollow cylinder connecting a pair of oppositely faced openings, one of the openings of said pair being in said toroidal chamber housing and the other of the openings of said pair being in said freely communicating chamber housing whereby fluid entering said fluid inlet region from said fluid input conduit via said fluid inlet flows via at least one of said tubular conduits to said freely communicating chamber and from the latter via at least another of said tubular conduits, said fluid outlet region and said fluid outlet to said fluid output conduit; said heat exchanger being supported only at said main header so that said heat exchanger can unconstra'inedly change mechanical dimensions in response to temperature changes.

9. A heat exchanger for use with a cylindrical burner comprising: a main header, said main header including a housing defining a toroidal chamber, first and second partitions in radial plane within said toroidal chamber for dividing the latter into a fluid inlet region and a fluid outlet region, a fluid inlet in said fluid inlet region adapted to be connected to a fluid input conduit, a fluid outlet in said fluid outlet region adapted to be connected to a fluid output conduit, said toroidal chamber housing being provided with a plurality of openings in a plane perpendicular to the axis thereof; a floating return header remote from said main header, said floating return header including a housing defining a freely communicating chamber, said freely communicating chamber housing being provided with a plurality of openings respectively facing the openings in the toroidal chamber of said main header; and a plurality of tubular conduits defining a substantially hollow cylinder, each of said tubular conduit including a plurality of fin means integral therewith, each of said tubular conduits connecting a pair of oppositely faced openings, one of the openings of said pair being in said toroidal chamber housing and the other of the openings of said pair being in said freely communicating chamber housing whereby fluid entering said fluid inlet region from said fluid input conduit via said fluid inlet flows via at least one of said tubular conduits to said freely communicating chamber and from the latter via at least another of said tubular conduits, said fluid outlet region and said fluid outlet to said fluid output conduit; said heat exchanger being supported only at said main header so that said heat exchanger can unconstrainedly change mechanical dimensions in response to temperature changes.

16. A heat exchanger for use with a cylindrical burner comprising: a main header, aid main header including a housing defining a toroidal chamber, first and second partitions in radial planes within said toroidal chamber for dividing the latter into a fluid inlet region and a fluid outlet region, a fluid inlet in said fluid inlet region adapted to be connected to a fluid input conduit, a fluid outlet in said fluid outlet region adapted to be connected to a fluid output conduit, said toroidal chamber housing being provided with a plurality of openings in a plane perpendicular to the axis thereof; a floating return header remote from said main header, said floating return header including a housing defining a freely communicating chamber, said freely communicating chamber housing being provided with a plurality of openings respectively facing the openings in the toroidal chamber of said main header; and a plurality of tubular conduits, each of said tubular conduits including a plurality of fin means integral therewith, each of said tubular conduits connecting a pair of oppositely faced openings, one of the openings of said pair being in said toroidal chamber housing and the other of the openings of said pair being in said freely communicating chamber housing whereby fluid entering said fluid inlet region from said fluid input conduit vi-a said fluid inlet flows via at least one of said tubular conduits to said freely communicating chamber and from the latter via at least another of said tubular conduits, said fluid outlet region and said fluid outlet to said fluid output conduit; said tubular conduits defining substantially a hollow cylinder with the fin means of adjacent tubular conduits in abutting relationship; 'said heat exchanger being supported only at said main header so that said heat exchanger can unconstrainedly change mechanical dimensions in response to temperature changes.

11. A heat exchanger for use with a cylindrical burner comprising: a main header, said main header including a housing defining a toroidal chamber, first and second partitions in radial planes within said toroidal chamber for dividing the latter into a fluid inlet region and a fluid outlet region, a fluid inlet in said fluid inlet region adapted to be connected to a fluid input conduit, said fluid inlet extending tangentially from said toroidal chamber, a fluid outlet in said fluid outlet region adapted to be connected to a fluid output conduit, said fluid outlet extending tangentially from said toroidal chamber, said toroidal chamber housing being provided with a plurality of openings in a plane perpendicular to the axis thereof; a floating return header remote from said main header, said floating return header including a housing defining a freely communicating chamber, said freely communicating chamber housing being provided with a plurality of opening respectively facing the openings in the toroidal chamber of said main header; and a plurality of tubular conduits, each of said tubular conduits including a plurality of fin means integral therewith, each of said tubular conduits connecting a pair of oppositely faced openings, one of the openings of said pair being in said toroidal chamber housing and the other of the openings of said pair being in said freely communicating chamber housing whereby fluid entering said fluid inlet region from said fluid input conduit via said fluid inlet flows via at least one of said tubular conduits to said freely communicating chamber and from the latter via at least another of said tubular conduits, said fluid outlet region and said fluid outlet to said fluid output conduit, said tubular conduits defining substantially a hollow cylinder with the fin means of adjacent tubular conduits in abutting relationship; said heat exchanger being supported only at said main header so that said heat exchanger can unconstrainedly change mechanical dimensions in response to temperature changes.

References Cited by the Examiner UNITED STATES PATENTS 1,963,857 6/1934 Lucas et al. 165-175 X 2,146,614 2/1939 Bergdoll 165-158 2,640,686 6/1953 Brown 165175 X 3,173,480 3/1965 ,Parker et al. '165-158 3,231,016 1/1966 Stewart et al. 165164 FOREIGN PATENTS 196,583 8/1923 Great Britain. 736,759 9/1955 Great Britain.

CHARLES I. MYHRE, Primary Examiner.

FREDERICK L. MATTESON, ]R., Examiner.