US2570006A - Gas-fired forced air flow unit heater - Google Patents

Description

Oct. 2, 1951 R. D. REED ETAL GAS FIRED FORCED AIR FLOW UNIT'HEATER 2 Sheets-Sheet 1 Filed Nov. 22, 1948 M K wm Z T R s E w m T R .2 n

ATT'OR N EY Oct. 2, 1951 R. D. REED ETAL GAS FIRED FORCED AIR FLOW UNIT HEATE lR 2 Sheets-Sheet 2 FIG. 3

Filed Nov. 22, 1948 ROBERT REED, JOHN s. ZINK,

FEM

ATTORN EY Patented Oct. 2, 1951 GAS-FIRED FORCED AIR FLOW UNIT HEATER Robert 1). Reed and John S. Zink, lfulsa, Okla.; said Reed assignor to said Zink Application November 22, 1948, Serial No. 61,502

4 Claims.

The present invention relates to space heating devices and more particularly pertains to such apparatus which may be suspended from the ceiling of a room for transferring heat to the air moving in the presence of portions of the heater.

.Qne of the more serious problems involved in the design of a unit heater for direct gas firin is the necessity of obtaining a maximum of heat from a minimum amount of space since'such heating units are adapted to be suspended from the ceiling of thespace or room to be heated. If the ceiling is low and not high enough i to accommodate the heater above the heads of the occupants of the room, a portion of the space on the floor becomes unusable. If the vertical dimensions of the heaterare such as to make it impossible tosuspend the device from the ceiling ina proper location, the heater mustbe 1ooatedin some disadvantageous position in order to avoid obstructing useful floor space. Itis accordingly one of the objects of the present invention to so construct the heating unit as to provide a space heater which may be suspended from the ceiling without rendering any portion of a conventional size room unusable, and to provide a heater having an overall vertical height of twenty-four inches or less.

In the past it has been customary to supply fuel into a relatively large combustion chamber for space heaters of this type and to employ a plurality of burners in unit heaters for space heating purposes. These prior devices having a plurality of burners allow the products of combustion to flow upwardly through a plurality of relatively narrow passages to a gathering chamher and thereafter to a downdraft diverter and then to the fine or stack for discharge to the outside air. Such structural features involve a number of disadvantages and it is difiicult, if not impossible, to move a suflicient volume of cooling air over the surfaces of the combustion chamber to provide efficient heat transfer and to remove sufficient heat from the combustion chamber. In these earlier type space heaters the greater portion of the cooling of the products of combustion is accomplished in the vertical narrow passageways. Such a structural ar rangement involves a lower temperature diiferential between the flue gases and the air to be heated. The heater is, accordingly ineflicient and elongated vertical passageways are required which result in a heater having extended vertical dimensions.

Another object of the present invention is to avoid the disadvantages of the prior devices by providing two combustion chambers arranged side by side, each of which is thoroughly scrubbed by cooling air under conditions of materially greater differentials than-employed inthe past with the result that the flue-gases leaving the combustion chamber are at a much lower temperature, thus requiring a minimum of convection cooling to provide suitable temperature of the gases leaving the unit enroute to the outside air.

Other objects and features of the invention will be more apparent as the present disclosure proceeds and upon consideration of the following detailed description and the accompanyingdrawings wherein a typical embodiment of the invention is disclosed.

In the drawings:

-ig. 1 is a side elevational view of a heater unit exhibiting the invention with parts thereof broken away to illustrate the internal structure.

Fig. 2 in the left portion is an end elevational view while the portion on the right is an end view with the louvre structure removed.

Fig. 3 is a transverse vertical sectional view taken on the line 33 of Fig. 1.

Fig. 4 is an enlarged side elevational view of the burner and fuel supply conduit with portion thereof broken away.

Fig. 5 is a sectional view taken on the line 5-5 of Fig. 4.

Fig. 6 is a sectional view taken on the line 6-E of Fig. 4.

The present invention is directed to a unit heater wherein fuel is released in two elongated zones at opposite sides of the burner and combustion takes place in two combustion chambers arranged side by side and of elongated dimensions measured horizontally of the heater. The products of combustion move upwardly in the combustion chambers and further move in two separate paths and each path is torturous. The hot gases then flow towards each other'and through cross-over tubes and thereafter movein further zig-zag paths and eventually escape through the stack into the flue. Theinvention includes a unique structural arrangement for the burner so as to provide two distinct elongated flames which are each directed into a distinct combustion chamber. chamber arrangement also facilitates the use of eflicient types of air passages over the combustion chambers so as to provide for an eflicient transfer of heat from the'products of combus- The double combustion.

tion to the air which moves in the presence of the heater.

Referring to the drawings, there is shown at H] an outer casing which may be formed of any suitable metal and in the embodiment illustrated is cylindrical shaped. This casing is provided with hangers whereby the casing and the heater unit may be suspended from the ceiling of a room to be heated. The casin I is provided with an opening in the top portion thereof for accommodating a short section of a flue pipe l2 which may be connected to a suitable chimney or conduit extending to the outside air.

Any type of conventional means may be provided for creating forced circulation of air over the heater and such means may take the form of a fan having blades M which are driven by a motor l6 mounted on a bracket structure at one open end of the casing Hi. The other end of the casing is may be provided with a louvre mechanism having movable flaps ll which may be adjusted in the well-known manner to direct the heated air passing from the heater in different directions as it leaves the apparatus.

Apparatus embodying the invention includes a unique structure for the burner, which is more clearly shown in Figs. 4 to 6. P It will be observed that in order to avoid excessive weight a single burner is employed in association with the two combustion chambers and so designed as to sup plya fuel mixture into each of the combustion chambers. The burner is shown generally at 28 which may be formed as a casting of elongated construction and having a conduit 2| forming an integral part thereof. The conduit 2| may be of a Venturi shape and is in open communication with the mid-portion of the elongated burner 26. The burner 26] is provided on one flat face with a plurality of openings or drilled ports 22 and these ports are arranged throughout the length of the burner. The elongated hollow casting is also pro vided with drilled ports or openings 23 on the opposite flat face and these ports are arranged at spaced intervals throughout the length of the burner. It will benoted from a consideration of 5 Fig. 5 that these ports are arranged at substantially diametrical parts of the burner and. the purpose thereof will be more apparent as the present disclosure proceeds. The ports 22 are displaced substantially one hundred and eighty degrees with reference to the ports 23.

An inlet opening 26 for a gas mixture is located centrally and axially with relation to the entrance portion of the Venturi conduit 2! and allows gas to flow at controlled pressure into this conduit and inducing a flow of air into the Venturi tube along with the gas. This air is regarded as primary air and is thoroughly mixed with the gas and caused to flow to the ports 22 and 23 disposed along the opposite sides of the elongated burner 20. A suitable gas supply pipe 2'! may be connected to the pipe fitting 28 for supplying gas under proper control and pressure to the inlet opening 26.

A pair of combustion chambers 3| and 32 are provided for the gas and air mixture issuing from the ports 22 and 23. Thus, separate and distinct flames are created, one at each side of the burner 20 as shown in Fig. 3. These two flames are elongated and rise in the combustion chambers 3| and 3'2. While the gas jets issuing from the ports 22 are arranged in a plane displaced substantially one hundred and eighty degrees from the gaseous mixture issuing from the ports 23, these flames nevertheless rise somewhat as illustrated in Fig. 3. As the flame begins at the burner, the buoyancy of the burning gases turns upwardly so that the gas issuing from the ports 22 escapes into the combustion chamber 3| and burning gases issuing from the ports 23 move upwardly into the combustion chamber 32. It will be observed at this point that the flames each extend throughout the length of the burner 23 and the combustion chambers are suitably dimensioned and extend substantially throughout the length of the casing [0. The path of the burning gases are each substantially curvilinear. The burner as herein described, when operating in conjunction with the two combustion chambers, provides two flames which are substantially as long as the combustion chamber and also quite thin in cross section. The flames move substantially parallel to the two side walls 33 and 34 of the combustion chambers and in contact with the side walls.

The combustion chambers are further defined by a hollow T-shaped metal member 38 which extends throughout the length of a combustion chamber and is open at its ends. This T-shaped hollow member includes a pointed lower end portion which serves to divide the hot gases rising from the burner 20 and to direct these into the respective combustion chambers 3| and 32. The top wall 31 of the hollow T-shaped member 3'6 is substantially flat and provides the bottom wall for a portion of torturous passages for the hot gases rising from the combustion chambers. The hollow T-shaped member is open at its end so that air to be heated may pass therethrough in the direction indicated by the arrows 40 and 4| of Fig. 1. The hollow T-shaped member may be supported on the end walls 43 of the combustion chamber and which also forms end walls for the torturous shaped flue passages shown in Fig. 3. The sheet metal structure forming the flue passages is so shaped that the hot gases rise in the direction of the curved arrows in Fig. 3 and through cross-over passages formed immediately above the top wall 3! where the hot gases again meet and rise through horizontally spaced openings 46. Thereafter the hot gases again separate and flow through the passages 41 and 48.

A further air conduit 5| is arranged in the upper part of the flue chamber through which air to be heated may move in the direction of the arrows 52 and 53 as shown in Fig. 1. This conduit 5| is hollow and substantially trapezoidal shaped in cross section and supported on the end walls 43 of the combustion and flue chambers. Thereafter, the hot gases pass through the stack |2 and escape through the chimney or other conduit to the outside air. It will be observed that the hot flue gases in conjunction with the hollow air conduits 3% and 5! extending through the flue chamber follow zig-zag paths and after the first confluence thereof the hot gases again separate into torturous-paths 41 and 48 so as to provide for a maximum of travel with a minimum of height for the heater. This arrangement provides for a thorough scrubbing of all heat transfer surfaces without the use of baffles or obstructions in the paths of the flue gases.

In apparatus exhibiting the invention, a radiant shield 68 may be arranged within the casing l0 between the combustion chamber or angular walls 33 and 34 and inner surface of the casing. This hemi-oylindrical shaped radiant heat shield extends upwardly and terminates with the ends approximately on .a plane passing through the center ofthe cylindricalshaped casing.

The apparatus includes means for concealing the flames of the burning .gasesandto prevent droppings of any incandescent particles. Such means may take the form of a pan 6| hinged at 62 to a base portion of the casing Ill. The pan BI is adapted to be detachably maintained in the closed position by means of a hook or detent 53 which may be moved to the unlatched position to permit the pan to be hinged downwardly whereby the burner structure may be inspected, cleaned or repaired. The base portion of the casing [0 adjacent the burner is provided with openings through which secondar air may be admitted to support combustion. A further heat shield 66 may be provided Within the pan 6 l.

While the invention has been described with reference to specific structural details and with regard tothe particular shape of casing and the heater elements, it will be appreciated that changes may be made in the shape of the parts and in the elements and the general organizations. Such modifications and others may be made without departing from the spirit and scope of the invention as set forth in the ap pended claims.

We claim:

1. In a space heater, an elongated casing adapted to be supported in a substantially horizontal position, an elongated burner arranged lengthwise of the casing along a lower portion thereof, vertically disposed members within the casing forming spaced side walls laterally of and above the burner, an elongated hollow T-shaped open-ended conduit lengthwise disposed within the casing with a lower leg thereof depending between said side walls and having a pointed lower edge terminating adjacent the top of the burner providing two individual combustion chambers, said burner having a series oi ports along one side for discharging a fuel mixture laterally thereof for rising into one combustion chamber, said burner having another series of ports along an opposite side for discharging the fuel mixture laterally of the burner for rising into the other combustion chamber, a member within the casing arranged in a spaced relation around a lateral side of the head of the T-shaped conduit providing a passage for the products of combustion from one combustion chamber around one side of the T-shaped conduit, a member within the casing arranged in a spaced relation around the other lateral side of the head of the T-shaped conduit providing a passage for the products of combustion from the other combustion chamber around the other side of the T-shaped conduit, a fourth member above the T-shaped conduit having openings therein through which the products of combustion from both chambers pass, an elongated trapezoidal shaped hollow open-ended conduit lengthwise disposed within the casing above said fourth member, members within the casing spaced around opposite sides of the trapezoidal shaped conduit guiding the products of combustion around each side of the trapezoidal conduit in two torturous passages, end walls closing the ends of said side walls and said members which provide the passages for the products of combustion, and means for directing air through both of said open-ended conduits and through the casing outside said members.

2. A space heater comprising, an elongated horizontally disposed casing, an elongated burner arranged lengthwise of the casing along a lower portion thereof, spaced vertically disposed side walls within the casing extending above the burner, a hollow T-shap-ed open-ended conduit arranged lengthwise within the casing with a lower leg thereof depending between said side walls and having a lower edge separating the zone between the side walls into two distinct combustion chambers, said burner having a series of ports along one side for discharging fuelllaterallythereof for rising into one combustion chamber, said burner having another series of ports along an opposite side for discharging fuel laterally thereof for rising into the other combustion chamber, a memberwithin thecasing arranged in a spaced relation around a lateral side of the head of the T-shaped conduit providing a passage for the products of combustion from one combustion chamber around one side of the T-shap-ed conduit, amember within. the casing arranged'in a spaced relation around the other lateralside oi the headofthe T-shaped conduit providing a passage for the products of combustion from the other combustion chamber around the other side of the T-shaped conduit, a third member spaced above the head of said T-shaped conduit having an opening therein through which the products from both combustion chambers pass, means for supplying fuel and primary air into a central portion of the elongated burner, means for guiding secondary air to positions for rising along both sides of the burner, and end walls closing said side walls and said members which provide passages for the products of combustion.

3. In a space heater, an elognated horizontally disposed casing, an elongated burner arranged lengthwise of the casing along a lower portion thereof, spaced vertically disposed side walls within the casing immediately above the burner, an open-ended conduit lengthwise disposed within the casing, elongated means depending between said side walls and having a lower edge terminating adjacent a mid-portion of the top of the .burner separating the zone between the side walls into two distinct combustion chambers, said burner having a series of ports along one side for discharging fuel laterally of the burner for rising into one combustion chamber, said burner having another series of ports along an opposite side for discharging fuel laterally for rising into the other combustion chamber, a member within the casing arranged in a spaced relation around a lateral side of the open-ended conduit providing a passage for the products of combustion from one combustion chamber around one side of the conduit, a member within the casing arranged in a spaced relation around the other lateral side of the open-ended conduit providing a passage for the products of combustion from the other combustion chamber around the other side of said conduit, a third member spaced above the top of said conduit having an opening therein through which the products of combustion chamber from both combustion chambers pass, end walls closing the ends of said side walls and said members which provide the passages for the products of combustion, and means for directing air through said open-ended conduit and through said casing outside said members.

4. In a space heater, an elongated horizontally disposed casing, an elongated burner arranged lengthwise of the casing along a lower portion thereof, spaced vertically disposed members forming side walls extending above the burner, a hollow open-ended conduit arranged parallel to 7 the burner within the casing'with a hollow le depending between said side walls, a lower edge of said leg terminating immediately above the burner providing two distinct combustion chambers, said burner having a series of ports along one side for discharging fuel laterally of the burner for rising into one combustion chamber, said burner having another series of ports alon an opposite side for discharging fuel laterally for rising into the other combustion chamber, a member within the casing arranged in a spaced relation around a lateral side of said conduit providing a passage for the products of combustion from one combustion chamber around'one side of said conduit, a member within the casing arranged in a spaced relation around the other lateral side of said conduit providing a passage for the products of combustion from the other combustion chamber around the other side of said conduit, a member spaced above the top of said conduit having an opening therein through 8 which the products from both combustion chambers pass, and end walls closing ends of said side walls and said members which provide passages for the products of combustion.

JOHN S. ZINK. ROBERT D. REED.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 919,966 Short Apr. 27, 1909 1,076,209 Kent Oct. 21, 1913 1,217,612 Leonard Feb. 27, 1917 1,447,142 Martin -1 Feb. 27, 1923 1,650,920 Wiltsie Nov. 29, 1927' 1,788,158 Humphrey Jan. 6, 1931 1,837,485 Rember Dec. 27, 1931 1,895,966 Bluemel Jan. 31,. 1933

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