All-weather hot air furnace

July 15, 1941.

F. R. DALY

ALL-WEATHER HOT AIR FURNACE

Filed Feb. 24, 1939

2,249,554

Sheets-Sheet 1

<img file="US2249554A_D0001.tif" />

July 15, 1941.

F. R. DALY

ALL-WEATHER HOT AIR FURNACE

Filed Feb. 24, 1939

2,249,554

Sheets-Sheet 2

<img file="US2249554A_D0002.tif" />

Patented July 15, 1941

2,249,554

UNITED STATES PATENT OFFICE

2,249,554 ALL-WEATHER HOT AIR FURNACE Francis R. Daly, Minneapolis, Minn. Application February 24, 1939, Serial No. 258,233 (Cl. 237—2) bination with a radiator positioned in the path of travel of the continuously circulating stream of air, whereby, when the demands for heat require it, the boiler will generate steam going to the 5 radiator at such pressures and temperatures as may be requisite and the continuously circulating stream of ail· will be heated by contact with the walls of said radiator in heat exchange with the said steam, in addition to being heated by 10 ’ contact with the walls of the boiler in heat exchange with the hot water therein.

It is a further object of my invention to carry the gases of combustion to the bottom of the chamber and pass them through heat exchangers 15 at said bottom and to a heat exchanger discharge smoke box at the rear of the casing and to cause the continuously moving stream of circulating air to pass over said heat exchangers, whereby . , when the room thermostat calls for more heat and 20 the oil burner or other heating means is turned on the continuously moving stream of air will be preliminarily heated by contact with the walls of said smoke-flue heat-exchangers and by heat exchange with the gases of combustion exhaust25 ing therefrom.

The full objects and advantages of my invention will appear in connection with the detailed description thereof, and its novel features are .particularly pointed out in the claims.

CO In the drawings, illustrating an application of my invention in one form—

Fig. 1 is a longitudinal sectional elevation view taken through the center of my air-conditioning .. .furnace.' Fig. 2 is a sectional elevation view of a CO'part of the furnace taken on line 2—2 of Fig. 1.

Fig. 3 is a sectional plan view of a portion of the furnace taken on line 3—3 of Fig. 1.' Fig. 4 is a front part sectional elevation front end view .., taken bn line 4—4 of Fig. 1.’ Fig. 5 is a sectional ⁴⁰ ’elevation view taken on line 5—5 of Fig. 1. Fig:

is a sectional plan view taken on line 6—6 of

Fig'. 5. .....

As illustrated, an outer casing 10, which may . be insulated in a customary manner, has support ⁴⁵ 'ed therein a boiler ! I spaced from the side walls of casing 18 to form ascending air passages, as indicated at 12, 13 of Figs. 2 and 5. The boiler 10’ may be specifically such a boiler as is disclosed in my Patent No. 2,141,238 wherein there is an •to outer shell 14 of circular cross section surrounding an inner shell 15. The outer shell is closed by an end plate 16 and the inner shell is closed by an end plate 17 spaced from the end plate IS, ' as clearly shown in Fig. 1. There is thus an an³⁵ nular chamber 18 about the inner shell 15 and

Claims.

My invention relates to all-weather hot air furnaces and has for its object to provide an organization of elements whereby a forced air circulation through the rooms to be heated is continuously maintained and heat exchanger means are provided of such a nature that heat will be delivered from the organization in accordance with the demands for heat resulting from outside temperature. Thus, if the temperature is relatively high, as in mild weather, but little heat will be delivered to the constantly-moving current of air; if the temperature is moderately cold a proportionately greater amount of heat will be delivered to the constantly-moving stream of air, and if the temperature is low, as in severe cold weather, a maximum adequate amount of heat will be delivered to the moving stream of air.

I attain the above objects by providing a furnace structure embodying a boiler with suitable means for delivering heat thereto, as an oil burner or the like; by providing a casing about said boiler with passages through which air can circulate to be discharged to the rooms; providing a blower or air-moving device which shall be continuously operative, that is, will· move a stream of air through the' appliance and to and from the rooms at all times; by carrying the exhausting furnace gases, from said boiler through heat exchangers exposed to incoming air so that said air will be preliminarily heated by heat exchange with the exhausting gases oil combustion; and providing means for passing said air around and over heat exchange surfaces of the boiler further to heat the air. and to heat the air sufficiently when the oil bumer is out of operation; and finally to provide radiators adapted to receive steam from the boiler whereby the air may be still further heated when severe’weather requires a maximum or larger amount of heat.

It is a principal object of my invention, therefore, to provide a - boiler and heating means therefor entirely enclosed within a casing so that the surfaces of the boiler become heat exchange surfaces for a moving stream of air and to circulate the air to and from the rooms through said casing and over said heat exchange surfaces and to have such circulation at all times continuous, with controlled intermittent operation of the burner, in contradistinction to the customary method of heating wherein operation of air movement and burner is for both substantially simultaneously intermittent.

It is a further object of my invention to-provide a boiler for the purposes above outlined which shall embody a steaming chamber in com

2,249,554 an end chamber 19 formed continuous with said annular chamber 18. The chamber 18, 19 contains the water to be heated and from which when desired steam is generated, the desired level of said water being shown at 20 of Figs. 1 and 5. 5 As clearly shown, the shell 15 has its center substantially below the center of the shell 14 so that the space above the shell 15, which constitutes the combustion and heat chamber of the furnace, is substantially greater than the space below shell 10 15, with the water level 20 controlled by a glass in the usual way low enough to leave a steaming chamber 21 in the space 18, 19.

Extending into shell 15, as shown in Fig. 1, •is an oil burner 22 of any well-known construe- 15 tion which discharges its flame into a primary combustion chamber 23 and against a refractory baffle 24. Operation of the oil burner is controlled by a thermostat shown conventionally at 70 and thermostat connections 71, all of well- 20 known construction. The combustion gases go from the chamber 23 to a second chamber 25 past a second baffle 26 and down through a third chamber 27 and a bottom passageway 28 to a smoke box chamber 29. The chamber 23, as 25 clearly shown in Fig. 5, is provided with refractory side walls 30, 31. Within the heat chamber in shell 15 are a multiplicity of U-tubes 32 which have portions extending along the top of the heat chamber and through the passageway 30 28 exposed to the heat of the flame and gases of combustion in the heat chamber, as clearly shown In Fig. 1. These U-portions are connected by loops 33 with extensions 34 which go into the water above the shell 15, and by loops 35 ³5 with extensions 36 which go into the water below the shell 15, whereby cooler water in the lower part of annular chamber 18 is caused to circulate through the U members 32 subject to the high heat within the combustion chamber in ⁴⁰shell 15 and to discharge into the upper portion of the body of water within the outer shell 11, all as fully described and claimed in my aforesaid Letters Patent.

Opening into the smoke box 29, as indicated at ⁴⁵37, Fig. 4, are a multiplicity of smoke pipes 38 which discharge into a vertical smoke box 39, as shown in Figs. 1, 3 and 6. The smoke box 39 extends upwardly in an air-inlet chamber 40 and discharges to the stack through a pipe 41 connecting with smoke box 39, as shown in Fig. 1. While I have shown the passage of the gases of combustion as through a series of pipes 38 and smoke box 39, it will be understood that this is just one form of heat exchanger which may be employed, and I contemplate the use of other forms of heat exchangers which are capable of accomplishing the purpose of my invention.

The air-inlet chamber 40 is connected with main air-inlet trunk 4’ which has therein a ⁶⁰blower 43 whose outlet 44 discharges downwardly into chamber 40 past a transverse partition 45. as shown in Fig. 1. The blower 43 may be of any desired construction, of any of the wellknown forms of air-moving devices, and is op- ^b5erated by a motor 45. The arrangement is such that the motor 46 operates the blower 43 continuously, constantly drawing air from the rooms to be heated and delivering it within the casing ₇₀10 past the heating instrumentalities therein and through an air-delivery trunk 47, whence it goes to the various rooms to be heated. There is a continuous unchanging circulation of air to, through and from the rooms to be heated and 75 through the casing and past the instrumentalities therein which exchange heat with said continuously moving stream of air.

It will be noted that the wall 48 of chamber 40 has the end plate 16 of the boiler protruding thereinto and cuts off said chamber 40 from within the main part of casing 10 except for ports 49 and 50, Figs. 2, 3 and 5. These ports, as clearly shown in Fig. 5, lead under the adjacent smoke pipes 38 so that the air being constrained to go beneath the smoke pipes by means of baffles 51 the incoming air thus is constrained to move about a heat exchanger formed of the smoke box 39 and the smoke flues 38, from whence it passes through the spaces 52 and 53 between adjacent pairs of smoke flues 38 directly beneath the shell 1 i of the boiler, being constrained to pass around said shell, which, with the hot water therein thus becomes a hot water radiator or heat exchanger for said air.

From the passages 12 and 13 the air is caused to wrap around boiler 11 or the outer shell 14 thereof and pass through a steam radiator 54 located above the boiler 11, as clearly shown in Figs. 1 and 5, baffles 55 and 56 in relation to discharge of main air delivery duct 47 constraining the air to flow along the surfaces of the elements making up the radiator 54. This radiator is supplied with steam from the steaming chamber 21 by a pipe 57, Figs. 1 and 5, and the return water goes back to the boiler preferably under the water surface therein through a pipe 58. A protector member 59, pressurestat 60 and thermostat and connections, all of usual construction, control the operation of the oil burner 20 in a customary way.

For cleaning the combustion chambers the burner may be withdrawn and a brush introduced through the burner opening indicated at 61, Fig. 4, or, if desired, additional sight holes closed by suitable plugs, not shown, may be employed.

The chamber 29 is closed by a casing member 62, which, as shown in Fig. 4, embodies a flange 63 secured by bolts 64 to the front of the casing 10. The smoke passageway '20 in the boiler and the several flue members 38 under the boiler communicating with chamber 29 can thus be exposed by removing the member 62, and accumulations of soot or other materials be readily brushed off of the inside of these passages. Some of this inaterial will naturally gravitate to the bottom of upright smoke box 39, and at the bottom thereof I provide a lateral extension 65, Figs. 3 and 6, which is closed by a thimble door 66. When this is removed any accumulations of soot at the bottom of smoke box 39 can be removed and also the walls of smoke box 39 can be brushed to complete the cleaning of the smoke carrying passages.

The operation of the foregoing instrumentalities is as follows: The air at room temperature enters chamber 40 and wipes the surfaces of the smoke box heat exchanger 39. From there this air goes through ports 49 and 50 and passes through and around the smoke pipes 38, thus preliminarily heating the air by exhausting gases of combustion. This preheated air will then pass around shell 14 of heat exchanger with the water therein. In mild weather the burner will be on very little. The amount of heat necessary to keep the rooms warm will come mainly from heat exchange with the hot water in the boiler, being aided whenever the thermostat 70 calls for heat, at the time when such aid is most effective, by

2.249,554 3 heat exchange with the hot gases of combustion in the smoke flues and boxes. As the temperature drops outside and the need for heat increases the burner will be on for longer periods of time and the water in the shell 14 will be progressively 5 made hotter and hotter. Up to a certain point sufficient heat will be obtained without the generation of steam. When, however, that point is passed, by reason of lowered outdoor temperatures, the boiler will generate steam, which will 1θ pass into the radiator 54 and there be in heat exchange with the air moving over the surfaces of the various parts of said radiator. In the event that a very great amount of heat is required because of excessive cold, the pressure of the steam, 15 and its consequent temperature in heat exchange may be raised as determined by the setting of the pressurestat.

It follows that with a constant flow of air through the furnace arrangement and constant 20 and continuous circulation of air through the rooms to be heated, there will at all times be just enough heat, as indicated by the thermostat 70, to meet the requirements of the thermostat in heating the rooms. In that way, and this is one 25 of the primary advantages of my invention, the undesirable and unpleasant effects of the turning on and off of the air circulation through starting and stopping the fan are entirely done away with and both the temperature and air movement con- 30 ditions within the rooms may be kept constant. This also avoids the stratification of air in varying temperature zones through the elevation of the room which inevitably takes place where the air movement is interrupted from time to time 35 along with termination of the action of the burner. All of this results in the air in living quarters being kept at all times in a uniform condition of movement and temperature which greatly increases the comfort and well-being of 40 those who are inhabiting such rooms.