US 3552377 A
Description (OCR text may contain errors)
United States Patent  References Cited UNITED STATES PATENTS 2,788,943 4/l957 Fauser, Jr. 126/85BUX 3,428,040 2/1969 Baker et al l26/85BX Primary Examiner-Charles J. Myhre Attorney-Gravely, Lieder & Woodruff ABSTRACT: A conduit assembly for conveying fresh combustion air to and flue gases away from the combustion chamber of a heater and including an intake pipe connectable with the inlet to the combustion chamber and a tapered flue pipe disposed within the intake pipe and connected to the out. let of the combustion chamber. An elbow fits on the opposite end of the intake pipe and a transition, which is contained `ilvithin the elbow, is connected to the opposite end of the flue pipe for changing the direction of the flue gases. The transition is adjustable for connection with the flue pipe at any selected location along the taper of the latter.
PATENTEU JAN 5 197| SHEET a UF 2 CONDUIT ASSEMBLY This invention relates in general to combustion-type heating devices and more particularly to conduit assemblies for maintaining optimum air flow through such heating devices.
The quantity of air admitted to the combustion chambers of combustion type heating devices, particularly those fueled with gas, must be controlled fairly precisely, lest the heater will operate inefficiently. lf the quantity of air is insufficient in proportion to the fuel, poor combustion results and similarly if excessive amounts of air are introduced the efficiency is lowered appreciably. One type of heating device currently available on the market, the sealed combustion chamber variety, derives all of its combustion air exteriorly of the building in which it is located and, of course, also exhausts the flue gases exteriorly. Accordingly, the combustion chambers on this type of heater are completely isolatedl from the interiors of the buildings in which they are installed, making such heaters ideally suited for use in confined spaces such as individual rooms. Many heaters of this type have their flue pipes disposed within their intake pipes and both pipes in turn are connected at their opposite ends to a single wall vent. When a single wall vent serves as both the intake for fresh combustion air and the exhaust for flue gases, the height of the vent above the heater has a significant effect on the heaters operation. For example, when the vent is high above the heater the differential in weight between the column of cool combustion air in the intake pipe and the column of hot flue gases in the flue pipe will be considerably greater than the weight differential for an installation having the wall vent located immediately above the heater,' and consequently a greater draft will be generated in the former. In other words, more combustion air enters the combustion chamber when the wall vent is located higher in the wall. Accordingly, conventional conduit assemblies for heaters of the sealed combustion chamber variety are not suited for use with wall vents of varying heights, but on the contrary must be confined to a critical length or height for optimum air flow. j
One of the principal objects of the present invention is to provide a conduit assembly connectable with a heater and capable of providing substantially the same draft through the heater irrespective of the height at which it is cut off. Another object is to provide an angled transition which connects with a tapered pipe at any desired location along the taper. A further object is to provide conduit assembly which completely isolates the combustion chamber of a heater from the interior of the room in which the heater is disposed. An additional object is to provide a conduit assembly which is simple in construction and easy to install.
These and other objects and advantages will become apparent hereinafter.
The present invention is embodied in a conduit assembly including intake and flue pipes for respectively conveying fresh combustion air to and flue gases away from a heating device. At least one of the pipes is more restrictive to the flow of fluid for a given increment of pipe at longer lengths than it is at shorter lengths so as to counteract the tendency of the draft to increase when the ends of the pipe are elevated.
The invention also consists in the parts and in the arrangements and combinations of parts hereinafter described and claimed. In the accompanying drawings which form part of the specification and wherein like numerals and letters refer to like parts wherever they occur:
FIG. 1 is a perspective view of a conduit assembly constructed in accordance with and embodying the present invention, the conduit assembly as illustrated interconnecting a heater and a wall vent disposed in an adjacent wall;
FIG. 2 is a sectional view taken along line 2-2 in FIG. l;
FIG. 3 is an enlarged sectional view of an elbow and transition forming part of the present invention; and
FIGS. 4, 5 and 6 are front, rear and side elevational views, respectively, of the transition.
Referring now to the drawings, 2 designates a combustiontype heater provided with a sealed combustion chamber 4 having an upwardly opening inlet box 6 provided with an inlet opening or lip 7 for receiving fresh combustion air and a laterally opening flue outlet tube 8 for discharging the products of combustion. The heater 2 is disposed within a room 10 adjacent to an exterior wall l2 thereof, and cut into the wall l2 above the heater 2 is a hole 14 into which a wall vent 16 is fitted.
The wall vent 16 (FIG. 3) includes a vent housing 18 which extends completely through the hole 14 and projects beyond both the inner and outer surfaces thereof and a pair of flanges 20 which circumscribe the housing 18 and fit against the inner and outer surfaces ofthe building wall l2, forming a weather seal therewith. At its outer end the housing 18 carries a pair of spaced baffle plates 22 and 24 and opening outwardly through an aperture in the inner plate 24 is a flue box 26 to which an outlet tube 28 is connected. Both the baffle plates 22 and 24 and the flue box 26 are preferably removable as a unit from the housing 18. The outlet tube 28 extends rearwardly through the vent housing 18 so as to form a pair of channels through the wall vent 16. One of the channels is, of course, the interior of the outlet tube 28 and that channel opens outwardly between the spaced bale plates 22 and 24. The other channel constitutes that portion of the housing 18 which is not consumed by the outlet tube 28 and that channel opens outwardly between the end of the housing 18 and the innermost baffle plate 22.
the wall vent 16 and combustion chamber 4 of the heater 2 are connected to one another through a conduit assembly 30 (FIG. 2) so that the products of combustion leaving the heater 2 at the flue outlet tube 8 may be discharged to the at mosphere through the outlet tube 28 of the vent I6, while the fresh combustion air from that portion of the vent housing 18 surrounding the outlet tube 28 can enter the heater 2 through its fresh air inlet box 6. More specifically, the conduit assembly 30 (FIG. 3) includes an outer elbow 32 having a boxlike configuration and being outwardly defined by a pair of sidewalls 34, front and rear end walls 36 and 37 and an upper wall 38. In juxtaposition to the inner end margin of the vent housing 18 the sidewalls 34 and the upper wall 38 turn inwardly in the provision of flanges 40 which align with the adjacent front wall 36 and form a continuation thereof. The flanges 40 and aligned front wall 36 inwardly terminate at arcuate margins which together encircle the rear end of the outlet tube 28 in spaced relation thereto. Attached to the flanges 40 and the aligned end wall 36 are mounting flanges 42 of a nose portion 44 which, being slightly smaller than the portion of the elbow 32 to which it is attached, projects into the inner end of the housing 18 and snugly engages the inwardly presented surfaces thereof so as to form an airtight seal at the juncture of the housing 18 and the elbow 32. The flanges 40 and 42, as well as that portion of the front wall 36 exposed to the interior of the wall vent 16, are located in spaced relation to the pipe 28 for permitting the flow of fresh combustion air into the elbow 32. At their lower ends the sidewalls 34 and the end walls 36 are bent inwardly and upwardly and then downwardly again in the formation of a peripheral groove 46 which opens downwardly and receives the upper end of a rectangular intake pipe 48.
The intake pipe 48 (FIG. 2), which is of identical cross-sectional shape throughout, may consist of a single section or multiple sections 50, and the side and end walls of each section 50 are reversely bent at their lower ends to form downwardly opening peripheral grooves 52 which are identical to the grooves 46 of the elbow 32. The grooves 52 of the lowermost section S0 receive the lip 7 on the fresh air inlet box 6 of the heater 2, the lip 7 being of the same rectangular shape as the pipe 48 and the lower end of the elbow 32.
A tapered flue pipe 54 (FIGS. 2, 3 and 5) of rectangular cross-sectional shape is disposed within the intake pipe 48, and it includes at least a lower section 56 having a laterally projecting nose portion 58 which projects into the outlet 6 of the combustion chamber 4 so that the products of combustion are discharged into the lower section 56. In this connection, it
should be noted that the outlet 8 and nose portion 58 are completely surrounded by the fresh combustion air within the inlet box 6, and that the walls of the flue pipe 54 are set inwardly from the walls of the intake pipe 48 so that they too are completely surrounded by fresh air. As previously noted the flue pipe 54 is of rectangular cross-sectional shape and is tapered, but only its end walls 60 taper inwardly toward one another beyond the outlet 8, its sidewalls 62 being parallel throughout the extent of the intake pipe 48. Like the intake pipe 48, the flue pipe 54 may consist of an additional section or sections 64, depending on the height of the wall vent 16 -above the heater 2. Similarly, the sections 64 are connected to one another as well as to the lower section 56 by bending the lower ends of their end and sidewalls 60 and 62 reversely to form a groove 66 for reception of the mating top of the next lower section 56 or 64, whatever the case may be.
The uppermost section 64 discharges into the outlet tube 28 within the wall vent 16 through an adjustable transition 70 located within the elbow 32 and also having boxlike configuration. ln particular, the transition 70 ,(FIGS. 3 6) includes a diront wall 72 formed integral with a pair of sidewalls 74 and an upper wall 76 having side flanges 77 which are turned downwardly across the side faces of the sidewalls 74 so as to seal the juncture ofthe walls 74 and 76. The upper wall 76 is, in turn, integrally connected with a backwall 78 along a bendable fold 79 in the metal and the backwall 78 has forwardly turned flanges 80 which facewise abut and slidably engage the inwardly presented faces of the'sidewalls 74. Op- .posite the flanges 80 the sidewalls 74 are provided with arcuate slots 82 which are concentric about the fold 79 and accommodate .sheet metal screws 84 which thread into the flanges 80 and hold the backwall 78 at any selected angle. The lower ends of the backwall 78 and the front wall 72 are reverfsely bent in the provision of downwardly opening grooves 86 which receive the upper ends of the tapered end walls 60 on the uppermost section 64. The sidewalls 74 of the transition 80 facewise abut and extend downwardly across the outwardly presented faces of the sidewalls 62 on the uppermost section 64, The front wall 72 is furthermore apertured and fitted with a cylindrical nose portion 88 which fits snugly into the rear -end of the outlet tube 28. Finally the transition 70 is held securely within the elbow 32 by brackets 90 and 92 which are attached to the flange 40 on the upper wall 38 and to the forward wall 36, respectively, of the elbow 32 by means of sheet r'netal screws.
To install the heater 2 for heating the room l0 a suitable location next to the exterior wall 12 is first selected and ahole l'4 for the wall vent 16 is created in the wall 12. Once the wall vent 16 is installed securely in the wall l2, the lower section "56 of the flue pipe 54 is inserted downwardly through the inlet v6 for the sealed combustion chamber 4 and its nose portion 58 'vis forced laterally toward the combustion chamber 4 and into engagement with the outlet 8 of the combustion chamber 4.
The inlet box 6 may be removed to facilitate this much of the installation. Thereafter, additional sections 64 are placed on f the lower section 56 until the flue pipe 54 extends upwardly to la point at least midway between the lower edge of the vent housing 18 and the lower surface of the connecting pipe 28. The uppermost section 64 is then cut off at the proper height so that its end walls 60 f'it fully withing the grooves 86 on the` front and backwalls 72 and78 of the transition 70 when the nose portion 88 of the transition 70 is in alignment with the f-rear end of the outlet tube 28. Next the transition 70 is removed from the elbow 32 and its screws 84 are loosened so as'to free the backwall 78 for swinging movement. The end :walls 60 at the upper end of the upper section 64 are then ufitted into the grooves 86, and the screws 84 are tightened, Elthereby drawing the flanges 80 against the sidewalls 74 so as to hold the backwall 78 in the proper angular position. Once the backwall 78 is properly positioned, the transition 70 is again `'installed in elbow 32 and the various sections 50 of the intake 'ipipe 48 are fitted around the flue pipe 54 and fitted into engagement with the lip 7 on the inlet box 6 as well as with themthe height of the wall vent 16 above the heater 2 is selves. When the ceiling of the room kl0 is close to the wall vent 16, it may be necessary to install the lower section 56 of the flue pipe 54 first, and then the lower section 50 at the intake pipe 48. The upper sections 50-and 64 of the intake pipe 48 and flue pipe 54; respectively, may then be moved into position with the latter disposed within the former. After the intake pipe 48 is also cut to the proper length, the elbow 32 and transition 70 are installed as a unit onthe upper ends of the intake pipe 48 and the flue pipe 54, and the entire unit is shifted toward the vent 16 to bring the nose portions 44 and 88 into engagement with the vent housing 18 and the connect.- ing pipe 28, respectively. If desired the baffle plates 22 and 24, flue box 26, and outlet tube 28 may be removed as a unit from the exterior of the building to facilitate connection of the transition 70 and outlet tube 28.`
When the building structure permits, the conduit assembly 30 may be installed on the inlet box 6 and the housing 18 on the conduit assembly 30 while the heater 2 is laying on its side. After the foregoing components are connected, they may be raised to the uprightposition, care being taken to align the housing 18 with the hole 14 through the flanges 20.
Since the flue pipe 54 and transition 70 are completely contained withing the intake pipe 48 and the elbow 32, respectively, the chances of noxious flue gases escaping into the room l0 are reduced considerably in comparison to heaters having exposed flues. g
Furthermore, the tapered flue pipe 54 imposes a greater impediment to the flow of air through the conduit assembly 30, as its length is increased and this offsets the tendency for theair to flow at greater velocities through the pipes 48 and 54 diie -to the larger weight differential between the gases in the 'two columns. That weight differential of course, increases as the elbow 32 and transition 70 are raised. ln other words, the flue pipe `54 offers greater resistance per increment of length to the flow of flue gases through it at longer lengths than it does ,at shorter lengths.
inasmuch as the backwall 78 of the transition 70 caribe secured in different angles it will accept the tapered fluter-pipe 54 at any location along its length (FIG. 2) and, consequently, not critical from both an installation and an operational standpoint. Thus, the conduit assembly 30 is ideally suited for use in-below grade installations such as heating basement rooms which are non mally cooler than the remainder of the building.
ln lieu of passing the wall vent 16 through a hole 14..;iiifthe room wall 12, an elongated version lof it may be extended through a window in much the manner that a window-typel airconditioner is installed in a window.
Furthermore, optimum flow can also be achieved by kkother means such as by tapering the intake pipe inwardly towardiithe combustion chamber 4, byimposing bafflesA in the tluegpipeti or intake pipe 48, or by utilizing-stepped intake or flue-pipes.
This invention is intended to cover all changes and modifications of the example of the invention herein chosenforgpyr.- poses of the disclosure which do not constitute departures from the spirit and scope of the invention. l
l. A conduit assembly for conducting combustioriairitoiarid for conducting the flue gases away from a heating de. chaving a combustion chamber provided with an inlet ,andtanioutlet, said conduit assembly comprising an intakef i c fonnected at one end to the inlet of the combustion ch' a flue pipe disposed within the inlet pipe and connectedtatiits one end to the outlet of the combustion chamber, avileast-one of the pipes being tapered to converge inwardly alongrthe direction of flow within that pipe so that it is more restmotiite to the flow of fluid for a given increment of pipe at longer lengths than it is at shorter lengths, whereby the tenderio'ytpf the draft to increase as a result of the greater weightdif ferential between the gases within the flue and intake pipesjin` 3. A conduit assembly according to claim 2 and further characterized by an elbow connected to the opposite end of the intake pipe, and an elbow-forming transition connected to the opposite end of the flue pipe for changing the direction of the flue gases, the transition being disposed within the elbow.
4. A conduit assembly according tovclaim 3 wherein the transition includes adjustable means for connecting it with the flue pipe at any selected location along the taper thereof.
5. A conduit assembly according to claim 3 wherein the flue pipe has a pair of parallel sidewalls and end walls which converge, and wherein the transition is provided with end walls for engaging the end walls of the flue pipe, the end walls of the transition being shftable relative to one another whereby the transition is connectable with the flue pipe at any selected location along its taper.
6. A conduit according to claim 5 wherein the transition includes sidewalls interconnecting the ends of its end walls, the transition sidewalls generally aligning with and forming continuation of the sidewalls of the flue pipe.
7. A conduit assembly according to claim 6 wherein the sidewalls and one of the end walls of the transition are mounted rigid with respect to one another, and wherein the other end wall of the transition is movable relative to the rigid sidewalls and rigid end wall.
8. A conduit assembly according to claim 7 wherein the shiftable wall of the transition has flanges which project toward the rigid end wall and facewise abut the side walls of the transition, and wherein locking means are provided for firmly securing the sidewalls and flanges together after the shiftable wall has been moved to the selected location.
9. A conduit assembly according to claim 8 wherein the transition further includes an upper wall extending across and i mounted rigid with respect to the rigidly mounted side and end walls, and wherein the shiftable end wall is swingably connected to the upper wall.
10. A conduit assembly according to claim 6 wherein the end walls of the transition are provided with downwardly opening grooves for receiving the upper ends of the end walls on the flue pipe, and wherein the sidewalls of the transition overlie the outwardly presented surfaces of the sidewalls on the flue pipe.
ll. A conduit assembly according to claim 6 wherein the intake pipe is of constant cross-sectional size and shape for substantially the entire length of the taper on the flue pipe, and wherein the flue pipe is of rectangular cross-sectional shape.
12. A heating device comprising a combustion chamber provided with an inlet for admitting combustion air to the combustion chamber and an outlet for exhausting products of combustion from the combustion chamber, a conduit assembly including a generally upwardly extending intake pipe having its lower end in communication with the combustion chamber inlet and its upper end located above the inlet, and a generally upwardly extending flue pipe having its lower end in communication with the combustion chamber outlet and its opposite end located above the outlet, whereby the presence ofa flame in the combustion chamber will induce gases in the inlet pipe to flow toward the combustion chamber and gases in the outlet pipe to flow away from the combustion chamber, at least one of the pipes being progressively more restrictive to the flow of gases to offset the tendency of the gases to flow at greater velocities for longer lengths of pipe than for shorter lengths, the restrictiveness being such that substantially the same flow rate maintained through the conduit assembly irrespective of the length of the progressively restricted pipe.
13. A heating device according to claim l2 wherein the upper ends of the intake and flue pipes are located substantially at the same elevation.
14. A heating device according to claim 13 wherein the flue pipe is disposed within the intake pipe.
15. A heating device according to claim 14 wherein the intake pipe has a substantially constantcross-sectional area; and wherein the flue pipe is tapered such that its cross-sectional area becomes smaller as it rises, whereby the cross-sectional area available within the intakepipe for the conduction of combustion air to the combustion chamber inlet becomes smaller toward the lower end of the intake pipe.
16. A heating device according to claim 12 wherein the flue pipe is tapered such that the cross-sectional area becomes smaller as it rises; and wherein a transition connects with the upper end of the flue pipe, the transition being adjustable so that it can be connected to the flue pipe at selected locations along the taper thereof.
17. A heating device according to claim 16 wherein vent means are in communication with the upper end of the tapered pipe through the transition.