US2022116A - Warm air furnace - Google Patents

Description

Nov.. 26, 1935. R. w. KRUsE v 2,022,116

' WARM AIR FURNACE Filed March 22, 1934 2 Shets-Sheet l INVENTOR. fofrr nf. Mea/5E.

@Mpx ffl@- ATTORNEYS.

Nov. 26, 1935. R. w. KRUsE WARM AIR FURNAGE v2 Sheets-Sheet 2 I filed March 22, 1934 ATTORNEYS,

Patented Nov. 26, 1935 gozan ATENT OFFICE WARM AIR FURNACE Robert W. Kruse, Indianapolis, Ind., assignor to Kruse Company, Inc., Indianapolis, Ind., a corporation Application March 22, 1934, Serial No. 716,765

4 Claims.

This invention relates to a heat transfer plant, and particularly to a so-called warm air furnace. It is particularly adaptable for installations in residences, store rooms and the like.

The principal feature of the invention resides in theA arrangement of the air passages and tubes for rendering maximum heating efficiency with a minimum of space and expense in construction andinstallation. By reason of the construction herein disclosed, the same heating eiciency is obtained in .a furnace having substantially half the diameter of an Vordinary warm air furnace. This is advantageous wherein space for accommodating a furnace is at a premium. It also adds to the. appearance of the furnace wherein the bulkiness of the usual warm air furnace is reduced toa compact, relatively small structure.

Another .advantage resulting from the relatively small and compact structure resides in the ability of transporting a furnace, removing it and reinstalling it in other locations. Thus, the lessee of a store room or residence may install a furnace of this character, and, upon moving to another location, may readily transport it.

The above advantages are accomplished by the provision of a plurality of angularly disposed ,air tubes mounted in. swirling relation to the combustion chamber, coupled with air swirling fins extendingr therethrough and a baffle' for causing 1 the hot gases from the burner to spread and pass upwardly about the angularly disposed air tubes. Air is projected by means of a blower through said tubes which gives it a swirling action, bringing it in direct contact with the heated walls of the tubes which in turn have .a maximum surface exposed to the'hot gases, as will be 'hereinafter more specifically described.

Other objects and features of the invention will be vreadily understood from the accompanying drawings and vthe following Vdescription and claims:` a

Fig. 1 is a front elevation of the furnace show- ,ing the combustion chamber in dotted lines associated with an air conditioning box connected with the intake. Fig. 2 is a central vertical section through the combustion chamber showing the air tubes in elevation. Fig. 3 is a section taken on the line 3-3 of Fig. 1. Fig. 4 is a central vertical section through an air tube with a baffle plate mounted therein. Fig. 5 is a plan View looking down on the furnace header.

In the drawings, there is illustrated a furnace having a relatively tall, cylindrical warm air casing III. In the bottom thereof there is a fire box I'I having an opening I2 through Which the usual oil burner may extend. (not illustrated) for gen- @rating heat in the usual and prescribed manner. The bottom portion of the casing surrounds the fire box in substantially spaced relation there- -to and is connected tangentially to an air intake 5 passage I3 as illustrated in Fig. 3, said passage connecting with a blower chamber of an air conditioning housing I4. Said blower chamber is provided with the usual blower (not illustrated) mounted on a shaft I5 and driven by a pulley I6 lo from an electric motor I'I. Air is drawn into said chamber and forced through the passage I3 through air conditioning filters I8 from an air intake I9.

Extending above the fire box there is a cylinl5 drical combustion chamber of steel with a flue opening 2| centrally disposed in the top thereof and a fire opening 22 centrally disposed in the bottom end surrounding the top of the lire box. The flue opening 2l is connected with a flue-or 20 smoke pipe 23 which extends laterally through the upper wall of the furnace ,and supports a baille block 24 suspended in the center of the nre box by a rod 25.

Mounted above the flue in the upper projecting 25 portion of the casing, there is an eccentric header 26 of greater diameter than the casing, from which the warm air leader pipes 2l project. The eccentric header incorporates the advantageous effect of a leader pipe, while providing a greater 30 circumferential area for the pipe connections.

The purpose and advantage of the eccentric header 26 is to permit the` leader pipes 21 to be grouped on one side of the furnace wherein it is desired, the said pipes extending in substan- 35 tiallyl one direction therefrom. This is particularly applicable to installations wherein the furnace is placed atthe rear of a store room or in a' corner lthereof and it is not feasible to extend the leader pipes from about its entire periphery. 40 In such installations, greater efficiency is acquired by arranging the header eccentric of the furnace as disclosed, so that the hot air generated therein will be drawn to one side of the furnace and set up a. steady flow in that direc- 45 tion. This arrangement not only accentuates the delivery of the warm air from one side of the furnace as is desirable in such installations, but permits of a greater number of lead pipes being connected with the one side thereof.

As illustrated herein, the bottom ledge or flange of the combustion chamber, indicated at 28 and surrounding the opening 22, is provided with a plurality of circular openings or holes located concentrically thereabout, there being provided a total of fteen of such holes illustrated herein. The corresponding ledge or top of the combustion chamber is provided with seven outer holes and eight inner holes arranged concentrically, as illustrated in Fig. 3.

The holes in the bottom and top of the combustion chamber are connected by air tubes 29, said tubes being formed of the usual heat-conducting material and welded within their respective holes so as to provide an air-tight passage from under the combustion chamber through the` top. As illustrated in Figs. 2 and 3, said tubes are arranged at an angle about the central portion of the combustion chamber, leaving an opening of approximately the diameter of the baiile block 24. The direction of the angular position of the tubes is arranged to give the air passing therethrough a swirling motion in the same direction as initiated by the tangential air duct I3. This will be noted from the arrangement of the tubes as indicated by arrows in Fig. 3.

Each tube is provided with a twisted or spiral baifle plate 3D, as illustrated in Fig. 4, for causing the air passing upwardly along the angularly disposed tubes to be twisted or swirled therein.

The combustion chamber is spaced inwardly from the casing by a corrugated spacer 3| extending therebetween through which air is caused to pass between the outer surface of the combustion chamber and the casing for insulating the combustion chamber from the casing and causing the former to remain relatively cool.

The individual air tubes have been indicated by letter in respect to their relative position, as shown in Figs. 2 and 3, the fifteen tubes being lettered a to o, inclusive. It will be noted that they are relatively spaced to provide room for sixteen tubes, one being left out to allow space for the hot water coil, not illustrated herein. Thus, the lower ends of the tubes 0` and a. are substantially spaced apart for the reception therebetween of such coil. n

Every alternate tube leads from the bottom of the combustion chamber to the outer series of openings in the top thereof while the intermediate tubes lead from the single series of openings in the bottom o-f the combustion chamber to the inner series of openings at the top thereof.

In operation, heat is generated in the fire box by any suitable type of oil burner, the flame and hot gases extending upwardly through the opening 22 within the combustion chamber. Said hot gases are therein capable of spreading out to the full diameter of the combustion chamber surrounding the air tubes 29. The baille block 24 forces the spreading of the hot gases and prevents their passing directly through thecenter of the combustion chamber between the tubes to the flue. n

After spreading throughout the combustion chamber and around the tubes, passing the baille block, the hot gases are then permitted to escape through the flue 23, the heat conducted thereby having been largely expended upon the tubes and the top portion of the flue within the upper part of the casing.

The numerous -air tubes afford a substantial radiating surface for the conduction of heat to the air passing through the tubes, and their angular relation to the upward movement of the gases affects a baffle which increases the efficiency of heat interchange over such types of radiating surfaces as extend directly in the line with the flow of hot gases.

This angular or swirling arrangement of the tubes further acts tov create a swirling action of .the hot gases so as to pass evenly about the entire peripheral surface of the air tubes whereby the outer sides thereof are heated to substantially the same extent as the inner sides, or, in other words, the entire surface of the tube is evenly heated by the gases. Coupled with this effect upon the exchange of heat, the current of air entering the casing tangentially effects its swirling action in the direction of the angular arrangement of the tubes so that the air is equally distributed throughout the fteen tubes herein illustrated instead of passing more readily through the nearer tubes than the more remote tubes.

In addition thereto, the spiral or twisted baiiles 30 extending longitudinally within the tubes cause the air passing therethrough to be twisted during its passage so as to increase the quantity of air coming into direct Contact with the heat conducting wall of the tube. The vair thus lforcibly swirled upwardly through the tubes is discharged from the top of the combustion chamber into the upper part of the casing in a highly heated condition for eventual discharge from the top of the furnace through the radially disposed leader pipes.

The swirling action created as above described has the further effect of causing an even distribution Vof warm air about the entire periphery of the upper portion of the furnace so as to cause a corresponding equal distribution in its discharge therefrom.

By reason of the multiple air passage formed by the corrugated spacer 3| between the combustion chamber and casing, the exposed surface of the furnace is maintained relatively cool, resulting in a minimum loss of heat and controlled discharge from the upper portion thereof.

The invention claimed is:

1. A warm air furnace comprising a fire box, a cylindrical combustion chamber, a cylindrical casing enclosing and extending above and below said combustion chamber to form an air heating chamber adjacent thereto, a plurality of air tubes extending through said combustion chambercommunicating through the top and bottom thereof with said air heating chamber, said tubes being spirally arranged about the axis of. said combustion chamberv to cause a spiral motion of the air passing therethrough, and means for forcing air into-said casing tangentially thereof for entering said tubes at the angle of their disposition whereby the air will be uniformly distributed therethrough.

2. A warm air furnace comprising a vertically disposed cylindrical combustion chamber having central openingsV formed in the end walls for receiving and discharging heated gases, a're box communicating with and below'the bottom opening, a flue for discharging said gases communicating with and above said chamber, said combustion chamber also having a series of openings concentrically arranged about said central openings,

a plurality of spirally arranged air tubes extendc ingfrom the bottom to the top of Vsaid combustion chamber and connecting the lower series of openings with their respective upper series Vin offset relation, a cylindrical casing enclosing and extending from below said combustion chamber to a position thereabove and spaced therefrom to form an air heating chamber, and means for forcing air into the bottom portion of said casing tangentially to said series of openings to cause the air to be uniformly distributed to the respective openings and tubes connected therewith.

3. A warm air furnace comprising a vertically disposed cylindrical combustion chamber having central openings formed in the end walls for receiving and discharging heated gases, a fire box communicating with the under side of said chamber, a ue for discharging said gases communieating with the upper side thereof, said combustion chamber having a single series of. openings concentrically arranged about the lower end of the chamber, and a double series of openings concentrically arranged about the upper end thereof, a plurality of spirally arranged air tubes extending from the lower to the upper end of said chamber, each of said tubes connecting a lower concentric opening with one of the upper concentric openings in offset relation, every other tube being connected with one series of upper concentric openings, and every other tube with the other series thereof, and means for causing air to pass through said tubes.

4. A warm air furnace comprising a fire box, a cylindrical combustion chamber, a cylindrical casing enclosing said combustion chamber to form an air heating chamber adjacent thereto, means for causing air to pass through said air heating chamber, an annular header of greater diameter than said air heating chamber and positioned eccentrically thereof to provide an overhanging section, a plurality of warm air pipes grouped together and communicating with the overhanging section of. said header, and means for causing a whirling motion of the air passing into said header for discharge through the overhanging portion thereof and the communicating group of air pipes.

ROBERT W. KRUSE.

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