US2053590A

US2053590A - Furnace

Info

Publication number: US2053590A
Application number: US476071A
Authority: US
Inventors: Frank A Whiteley
Original assignee: Individual
Current assignee: Individual
Priority date: 1930-08-18
Filing date: 1930-08-18
Publication date: 1936-09-08
Anticipated expiration: 1953-09-08

Description

Sept. 8, 1936.

F. A. WHITELEY FURNACE 4 Sheets-Sheet 1 Original Filed Aug. 18, 1930 P 1935- F. A. WHITELEY 2,053,590

FURNACE Original Filed Aug. 18, 1930 4 Sheets-Sheet 2 Invenl-or: wl'ufelzld.

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pwymfi FAWHWELEY msww FURNACE Original Filed Aug. 18, 1933 4 Sheets-Sheet 3 F. A. WHITEL'EY I FURNACE 4 Sheets-Sheet 4 Original Filed Aug. 18

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Inventor PK. Whit-elegy f'l'or'negs Patented Sept. 8, 1936 UNITED STATES PATENT oFFicE Application August 18, 1930, Serial No. 476,071

' Renewed February 3, 1936 11 Claims. (Cl. 120-116) My invention relates to furnaces for heating rooms by gas or other fluid fuel, particularly rooms of houses.

The principle of modern heating is based upon a source of heat located at any desirable point, usually, in house-heating, in the basement of the house. Heat exchangers are subject directly to said heat, and the transfer medium which contacts with the heat exchangers takes the heat therefrom and by one or another form of circulation conveys the heat to the-rooms to be heated. The transfer medium may be steam or hot water or vapor, in all of which cases the air in the rooms is heated by. iirculating about additional heat exchanger'members known as radiators. Or, the heating medium maybe the air itself circulating about the primary heat exchanger and in and through the rooms and thus conveying the heat directly to the rooms to be heated.

' Obviously, as regards the transfer of heat from the primary heat exchanger to the transfer medium the principle of operation must be essentially the same, whether such transfer medium be air, hot Water, steam or vapor. 'And that principle must, of course, involve the exposure of more or less heat exchanger surface subject to the heat in the furnace on one side and contacting with the transfer medium on the other side.

In the use of gas or other fluid fuel for producing heat, a material diificulty is encountered because of the rapid combustion of the fuel with little residual radiant energy, the necessary employment of a continuous and relatively large draft of air, and the consequent rapid convection of heat directly to the stack or chimney.

It is the object of my invention to overcome this difliculty by providing novel means for greatly increasing the heat exchanger surfaces subject to the hot gases of combustion on one side and to the transfer medium on the other side. I have discovered that this object can be attained effectively by providing a, multiplicity of finned tubes of relatively small diameter, preferably with the fins integrally united with the body of the tubes,

through which the combustion gases are caused to move by means of a fan or blower placed in or near the stack which causes artificial draft through said tubes, and by providing two sets of said tubes, one set being contacted by the transfer medium in its coldest state as it comes from the rooms being heated, and the other set being contacted by the transfer medium at or near the time when it starts on its circulating journey from the furnace to the rooms to be heated.

It is a further object of my invention to discharge a mixture of fluid fuel and air into the combustion chamber at a point above thebottom thereof which will comprise the lower part of the combustion area and to introduce secondary air into the fire-chamber-below said combustion area, and 5 to positively move said secondary air into. the region below the combustion area and through the mixture of air and gas to effect complete and perfect combustion, which object. is attained in such manner that the exact amount of air requi- 10 site for complete combustion, and no more, can. always be supplied to the aforesaid primary mixture of fluid fuel and air regardless of weather conditions. r

A further object of my invention is to provide 15 the furnace with a normally open'vent to the stack, which, however, will close simultaneously with the starting of the fan or blower for artificially moving the combustion gases, and which will always remain open if said fan or blower-is 20 for'anyreason inoperative.

Another object of my invention where the transfer medium is air, is to provide a'particularly effective airmoistening device in conjunction with the air circulating passageways after the air has 25' passed aroundand across the battery of fin tubes and has been heated for delivery to the rooms to be heated.

The full objects and advantages of my invention will appear in connection with the detailed 0 description thereof, and its novel features are particularly pointed out in the claims.

In the drawings illustrating applications of m invention,-

Fig. lis a sectional elevation view longitudi- 35 nally of a form of the invention wherein air is employed as a transfer medium. Fig. 2 is a sectional plan view on line 2 2 of Fig.1. Fig. 31s a sectional elevation view of a heating device embodying my invention wherein the transfer me- 40 dium is water, steam or vapor. Fig. 4 is a sectionalplan view on line 4-4 of Fig. 3. Fig. 5 is a sectional plan view on line 5-5 of Fig. 3. Fig. 6 is a part sectional elevation view on line 6-6 ofFig. 3. Fig. 7 is a transverse or end sectional elevation view on line 1-1 of Fig. 1. Fig. 8 is a partial sectional end elevation view on line 88 of Fig. 1. Fig. 9 is'an end elevation sectional view on line 99 of Fig. 1. Fig. 10 is a sectional plan view on line Ill-III of Fig. 1. Figs. 11 and 50 12 are diagrammatic showings of a motor designed to control the burner and suction fan and the blower and water valves, respectively. Fig. 13 is a diagrammatic view showing the circuit breaker for the water valve circuit. Fig. 14 is a wiring 55 diagram showing the manner of simultaneous operation of fuel gas control motor, combustion gas control motor and secondary air-inlet valve.

I will first describe the form of invention where air is used as the transfer medium. In general there is a rectangular outer casing Ill embodying two main chambers H and I2. Chamber II is the air inlet chamber and communicates at its top with a secondary air inlet chamber l3 which overlies the top of chamber l2. Chamber l2 has formed therein and centrally positioned with respect to its walls, a fire chamber l4, in the bottom of which are a multiplicity of burners l5 of standard construction, which, as shown, are fed by gas through Bunsen feed pipes l6 leading from a gas manifold H to which gas is supplied from any usual source of supply through a thermostatically controlled valve l8. An air passageway l9 at the bottom of the casing leads to a vertical passageway 20 which supplies air to the burners l5, and a thermostatic pilot light 2| of common con-. struction controls the valve I3. The passageway I9 is normally closed by a door 22 which is connected by a cord 23 and rock-lever 24 and cord 25 passing over pulley 26 with an arm 21 onthe gas valve l8. When the thermostat closes the circuit to open the valve the stem 21 rises and through the above-described connections lifts the air valve 22 to admit secondary air to the burners.

Extending longitudinally across the fire cham-- ber I4 is an air box 28 which has its side walls spaced from the fire chamber walls as indicated at 29 and has top and bottom walls 30 and 3| each formed with a multiplicity of perforations or holes 32 between which extend a corresponding number of tubes 33. Each of'the tubes 33 has-formed thereon preferably integral with its body a mu]- tiplicity of circumferential fins 34, the tubes and fins being subject to the air forcedthrough the air box. The number of tubes 33, of course, may be varied according to their diameter and the size of the air box. In the illustration given there are shown thirty-nine one inch tubes, which will be a satisfactory number for a heating plant for a home of from six to ten rooms. The heat chamber l4 extends above the air box 28 into an upper portion 35 preferably formed with an unbroken, slanting top 36 which overlies the air transfer passageway 31 into which the air. box 28 discharges. A door 38 opens through a passageway 39 into the lower part of the fire chamber adjacent the burners I5, and another door 40 opens through a passageway 4| into the upper portion 35 of the fire chamber to give access thereto for inspection and cleaning of the tubes. As shownin Figs. 1 and 9, a smoke vent 42 discharges from the upper part of the top portion 35 of the fire chamber through a pipe 43 and riser 4-5 which discharges into a box 45 from which extends the furnace pipe 46. A valve plate or damper 41 has secured to it a weighted arrnwhich normally holds it in the position shown in dotted lines so that the riser 44 is open to discharge through the smoke box 45 into the furnace pipe 46. A suction fan or blower 48 mounted as hereinafter described discharges through its leg 43a in suchwise that the blast of air impinges upon the damper 41 and swings it into full-line position, where it cuts off the opening of riser 44 and causes all furnace gases to discharge through the fan.

Exactly the same kind of an arrangement is shown in Fig. 3 applied to the steam or hot water boiler embodying my invention there-illustrated, and its principle of operation and purpose to be served are the same in either form of the invention. That is, normally at all times there is an unobstructed passageway leading from the upper portion of the fire chamber direct to the furnace pipe and stack. Thus, if there is any leakage of gas when the furnace is not in operation it will pass out to the chimney. The blower operates to cause the gases to pass through the many tubes of small diameter and of long and tortuous character overcoming the friction resistance which otherwise would prevent proper exhaust of gases of combustion. If, however, for any reason the blower should not operate, the direct discharge from the furnace as described furnishes a safety gas escape arrangement which will insure against accident and will permit the furnace to operate without being injured even when and if the blower for any reason is inoperative. Further, when the gas first turns on there is always a slightly explosive initial combustion, and the direct passage to the furnace pipe and stack takes care of this so as to prevent undue pressure upon the furnace walls or unpleasant noises. When, however, the blower starts into operation as it is intended to do, the valve closure is thrown down to shut off the direct passage from the upper portion of the fire chamber and all the gases of combustion are caused to pass through the small finned tubes which constitute the primary and secondary heat exchanger elements of the system.

Connected with theupper portion 35 of the fire chamber is a box 49 which, as shown in Fig. 10, extends from one wall to the other of the casing Ill and which opens into the fire chamber through a passageway 50. Connected with the box 49 are a multiplicity of 8 tubes 5|, all as clearly shown in Figs. 1 and 10. Each of these tubes has thereon a multiplicity of fins 52 preferably integrally formed with the tubes, and the tubes are bent as shown in the form ,ofan S and connected at 53 with the lower side of a smoke 'pipe 54. This smoke pipe has at its center a riser 55, and mounted horizontally upon the riser 55 is the suction blower 48, which is driven by the motor 56 and which discharges to the stack, as hereinbefore described.

The operation of the gas burners and the travel of the furnace gases from theburners to the stack, will now clearly appear. The electro-magnetic gas valve I8, and the motor 56 driving the blower 48 are on a common circuit 560. (seeFig. 14) which is controlled by a thermostat ,in'one of the principal rooms to be heated in a wellknown manner. When the circuit 56a is closed as at l8a it will simultaneously cau'se operation of the valve l8 to admit gas to the burners i5, open the air door 22 to admit secondary air to said burners and start the suction blower and motor 56. As soon as the motor 56 starts, the blast of moving air from the blower 48 operates to close the valve door 41, which is effectively held closed by the pressure of the air driven by the blower 48. This provides a complete safety control as already has been fully detailed. Moreover, in this construction and in that later described for the boiler shown herewith, there is a positive feed of secondary air into the lower part of the fire-chamber and below the released mixture of gases of combustion andbelow the combustion zone thereof. The secondary air is positively moved into the combustion zone to take part in effective combustion, and its rate of flow is constant regardless of changes in atmospheric 'air box 28.

pressure from changed weather conditions, and regardless of the temperature of the interi'orof the fire-chamber and smoke passages, whichmay start cold or nearly cold, and,'of course, ultimately become greatly heated. This is an important feature of my inventon which greatly aids in producingsatisfactor-y and highly efficient combustion. I

The air travel through" the'furnace is short and simple, but because of the large'amount of finned tubing across which it'must traveland with which it is caused to contact, it is in a high degree efficient. The air returns fromthe various rooms through pipes 51 which discharge into the top of the air intake chamber II and its is driven through the air box 28 going across and around the finned tubes 33 and into the'air'transfer chamber 31. From the air transfer chamber 31 air legs or passageways Stand-65 lead downwardly on either side of the slopingwalls of an air moistener 66 located below theair transfer chamber 31. From the

air legs

64 and 65 the air passes through a large opening 61 under the bottom of the fire chamber I4 and thence through passageways along the sides and end of the fire chamber to the air delivery chamber 68, from which it goes by means of pipes 69 to the various rooms to be heated. The air moistener 66 pref erably will be formed of aluminum, and it is. positioned below the air transfer chamber 3'! so that its sloping surfaces are wiped by the strong blast of highly heated air coming from the air box 28. A water pipe I formed with a multiplicity of discharge nozzles II is adapted to throw a fine spray of water upon the peak of the air moistener 66 such as to cause the same to move in a thin film or sheet down the sloping sides of the air moistener, which film or sheet is contacted by the moving streamsof hot air. A hood I2 over the pipe I0 and nozzle H protects the spray from the moving air so that it will not be carried as free water therewith. The sides of the air 'm'ois tener B6 are carried around at the bottom in almost closed tubes, as indicated at I3 in Figs. 2 and 8. Excess water will gravitate into the tubes I3 and be carried away to the sewer or any suitable retainer means through pipes 14.

As shown in my co-pending applications, Serial Numbers 261,775and 466,689, of which applications this application'is a continuation inpart, the solenoid or motor for the fuelsupplying mechanism and the motor for the fan or blower I have their circuits closed by a. motor which is set in operation by the thermostat, the motor first operating to turn on and light the gasor other fluid fuel, and then, in turn, after a' predetermined period of time'has gone by operating to close the circuitto set in operation the motor'for driving the main blower. Means for effecting the similar operations are provided in the invention of this application. The thermostat control motor of the type shown in my application Serial Number 261,775 is shown diagrammatically in Figs. lland 12. ever, when this motor operates to turn on the fuel it simultaneously operates to'startthe suc- Here, how-' tion blower 48, and when the motor further sets in operation the motor for driving the. main blower 58 it simultaneously opens the valve to admit water to flow through the pipe Ill to the 'air moistener 66. As shown in Figs. 11 and 12,

a motor I I1 is in an electric circuit controlled by the thermostat not shown. This motor has connected therewith a pair of cam discs H8 and H9 with long and short cam faces H and H6.

The long cam face is adapted to engage a lever I20 which when rocked will close a contact switch I2I, and the short'cam'surface H6 is adapted to engagea lever I22 which will close a contact switch I23. In the position shown in Fig. 11 both levers are in neutral position off of the cam surfaces with both circuits open, which is the position when the furnace is inoperative. The cams rotate in the direction of the arrows. The first result of rotation .is to close switch I23, which will have the effect of turning on the gas through electrically-operated valve! and starting the blowerv 43. The cam disc will continue to turn until the lever I20 goes up on the long cam member H5, which will close the switch I2I, at which time the motor II! will go out of operation. Closing of the switch I 2| will close the circuits to turn on the-blower 58 and open thewater valve I5 unless the circuit to the solenoid 60 is broken at the circuit breaker 16 by the operation of the hydrostat '11. The short cam surface. is. preferably about one-half the length of the longcam surface. If, then, the

motor is set to rotate the discs in-say-six minutes, the burner will be on for two minutes before the blower is started in operation, thus giving the system opportunity to warm up before air is delivered to the rooms. tion will be such that the second operation thereof, when the rooms reach a desired temperature. will rotate the discs twice as faras on the first operation' When that operation takes place the burner will be turned off at once and the blower will continue to operate for four minutes after the burner is turned off, thus draining the system of its .stored heat. As shown in detail in Fig. 13v water flow to pipe is controlled by a valve I5 of a common type which. is self closing. A solenoid 60 adapted to be put in circuit with the motor iii of the blower 58 opens said valve to admit water to the pipe and airmoistener only drostat TI. This arrangement is such that it the air in the rooms beingheated and conditioned contains moisture in excess of a certain predetermined percentagesay 65 per cent-the hydrostat will be actuated thereby to break the water valve circuit and no water will be delivered to the air moistener. At all other times, however, whenever the blower 58 is in operation to drive the air through the .systcm and to the rooms the water'valve will be open, permitting the spray of Water to fall upon'the air moistener 66 and to be carried in a sheet or'film, over the surface thereof to be evaporated by the rapidly moving and very hot air wiping these films and surfaces. This air-moistening arrangement is effective to introduce moisture rapidly up to any desired quantity into the air and yet when the percentage of moisture desired is reached there will be; immediate shut-off of further water-supply.

. The main blowermotor M will be mounted on The motor opera-' a stand 18,- as shown in Fig. 9. In order to avoid carrying the vibration from the motor to the easing I connect the nozzle or discharge pipe 58 of the blower with a piece of air-impervious fabric 18 and the casing in the blower head 80 of the blower 58 is connected with the casing member 8| by means of a similar fabric sheet indicated at 82. In this manner novibration from the motor or blower is transmitted to the furnace casing. As already detailed, the motor BI is positioned outside of the main casing ID as shown in Fig. 9, the casing being cut away as indicated 4 at 62, butthe vertical passageway 83 is provided alongside of the fan and at the back of the blower to permit the air passing down through the sheets of 8 tubes 5I to go down on both sides of the blower and pass around to the blower entrance 83. To prevent too much air going directly down on the entrance side I provide a baille 84, as indicated in Fig. 9.

The construction for a steam, hot water or vapor boiler shown in Figs. 3 to 6 inclusive has most or many features which are common to those shown'in' the other figures where the heat transfer medium is water. The control of the furnace gases, as has already been pointed out, is identical in the above constructions. Other common features will appear as the construction of these figures is now detailed.

The boiler is of usual construction formed of cast iron having an outer shell 85 extending from a closed bottom 86 to the dome 81 at the top of the boiler. Within the shell 85 and a short distance above the bottom 86 is formed the lower portion of a fire chamber I21, the same being secured in position by means of ribs 88 cast integral with the outer shell 85 and the side walls of the fire casing chamber I21. The fire chamber has a closed bottom wall 88 between which and the bottom of the furnace 85 is a bottom chamber 80, and this is connected by vertical legs 8I with a primary heat exchanger chamber 82 whose bottom and top walls are formed respectively of a perforated top wall 83 of the fire chamber I21 and a perforated bottom wall 84 of the secondary fire chamber or smoke chamber 85 located immediately below the dome 81. The primary heat exchanger chamber 82 communicates with the dome 81 through a secondary riser 86 in a well-known manner. The heat exchanger medium (steam, hot water or vapor) passes through the dome 81 through a riser or risers 81 to go to the radiators in a well-known way, and the medium returns through-return pipes indicated at 88 to the lower chamber 88 which constitutes a secondary heat exchanger chamber.

Burners 88 in the fire chamber are fed with gas controlled b7. athermostat in the same manner as that already described for the device shown, particularly in Fig. '7, and secondary air is supplied through a vent I00 controlled by a door valve IIII, also as heretofore described. The combustion gases pass from the primary fire chamber I21 through a multiplicity of finned tubes I02 which are circumferentially disposed and obliquely turned as shown in Fig. 3, both to avoid the riser 86 and because in the oblique basket shape the finned tubes will be better contacted by the water rising from the legs 8I and traveling across the primary heat exchanger chamber 82 to the riser 86 and dome 81. The gases of combustion may travel from the second ary fire chamber through the direct discharge pipe 43 to smoke pipe 46. However, these gases will preferably beconstrained to pass downwardly through a leg I 85 to a spreader tube I 06 from which they go through finned U tubes I01 back to a similar spreader passageway I08 and thence to the riser 55 that goes to the blower 48.

It will be seen that the travel of the gases of combustion in the boiler exemplification of Figs. 3 to 61s substantially identical with its. travel in the air furnace of the other figures. The gases of combustion go from the primary fire chamber I21 through a multiplicity of finned tubes I82 to the secondary fire chamber 85. From thence they travel through a series of finned tubes I01 in the secondary heat exchanger chamber .80 and pass to the blower and through that to the stack. And in this form also there is perfect safety because at all times when the blower 48 is not in operation there is direct communication between the secondary fire chamber 85 and the furnace pipe 46 andstack.

Likewise, the heat transfer medium (steam, water or vapor-primarily water-in the boiler casing) has substantially the same form of travel in. both forms of the invention. It comes from the rooms that are heated through the return pipe 88 and enters the inlet or secondary heat exchanger chamber 88 where the gases of combustion and the return medium are both at their low temperatures. It then passes upwardly through the legs 8|. into the primary heat exchanger chamber 82 and passes across the finned tubes and the fins thereof to the riser 86 and the dome 81, from which it goes to the rooms to be heated.

A door I88 of common construction opens into the primary fire chamber I21 and a clean-out door II) opens into the secondary fire chamber 85. Theboiler construction above described presents no manufacturing problems. The main part of the boiler is a simple casting proposition easily'taken care of by those skilled in the art of heavy casting. Because of the fact that the finned tubing in the boiler form is at all times contacted with water, aluminum tubing with fins integrally cast thereon of well-known construction may be employed, which will eliminate corrosion or rusting and also make a water contact much less liable to scale over than steel or iron. The tubing will be of relatively small JJI diameter; the tubes I02 are designed to be shown as one inch tubes and the tubes I01 as ,one and I one-half inch tubes. This tubing is commensurate with that employed in the hot air form of the invention. In either case it is possible effectively and certainly to move the gases of combustion through these numerous tubes of very small diameter and overcome the friction incident to such movement by the use of the suction bower 56. As shown, this is ineach case positioned vertically, the motor and the rotor connected therewith being .mounted on vertical thrust bearings and in such position that the motor and bearings are not subjected to the heat of the furnace. In both forms there is liable to be some. condensation from combustion gases being cooled below their dew point in the secondary heat exchanger chambers. As shown in Fig. 1, the 8 tubes 5| have a downward slope throughout their length so that this condensate can discharge into the trough III formed in the bottom of the casing passage 48 which was a downward slope, as clearly appears in Fig. 9 and discharges outside of the furnace through pipe I I2. Similarly, condensate from the tubes I 01 in the secondary heat exchanger chamber of the boiler will be discharged through outlet pipe H3. The position of the suction blower 48 rotating about a vertical axis with its bearing at the top and drawing the gases of combustion in through an opening at the bottom, is such as not only to keep the bearing member from exposure to heat (an additional protective plate may be inserted at the top of the blower chamber if desired), but renders it also impossible for any condensate to reach the bearings or the motor.

I claim:

1. A heating device comprising a furnace embodying a fire chamber, heat exchanger means in the furnace including a multiplicity of tubes of small diameter for carrying ofi the hot gases of I combustion, means for effecting circulation of a heat conveying medium about all said heat exchanger tubes, a smoke pipe outside the furnace. a duct leading from the discharge of said tubes to the smoke pipe, a second duct leading directly from the top of the fire chamber to the smoke pipe, a centrifugal blower located to draw the hot gases through said tubes and from said first-named duct and discharge them into the smoke pipe, and a valve closure for said second duct positioned so that said second duct is open to the smoke pipe when the blower is not in op-- eration and actuated by operation of the blower to close said second duct when the blower is in operation.

2. An air conditioning device comprising a furnace having a smoke discharge vent opening direct to the stack, heat exchanger means in said furnace including a multiplicity of tubes for carrying off the hot gases of combustion independently of said direct stack discharge, a suction blower for moving the gases through the tubes and discharging them to the stack through a pipe which is connected with said direct discharge, a damper valve in said pipe with means to hold it in position for maintaining the direct discharge open when the blower is not in operation, said damper being positioned to be impinged by the blast from the blower and thereby caused to effect closure of the direct smoke discharge.

3. In a furnace fire chamber a smoke discharge pipe and two passages leading from the firechamber thereto, one of said passages being normally open to the stack, a suction blower in the other passage, a damper valve normally in nonblocking position relative to said normally open passage, and means operated by the draft from the blower to cause the damper to close said passage when the blower is in operation.

4. A heating device employing steam or hot water as a circulating medium comprising a shell adapted to hold said medium, a combustion chamber within said shell and having its walls spaced from the lower, upper and surrounding portions thereof to provide interconnected primary and secondary heat exchanger chambers above and below the combustion chamber, respectively, heat exchanger members for carrying off the gases of combustion in both of said chambers, a smoke pipe having normally open connection with said primary heat exchanger members only, a blower having normally closed connection with said smoke pipe and connections to the secondary heat exchanger members first and then the primary heat exchanger members for drawing the gases of combustion through all said members and discharging them to the smoke pipe, and means rendered operative when the blower is in operation for closing the first connection and opening the second connection to the smoke pipe.

5. A heating device employing steam or hot water as a circulating medium, comprising a shell.

adapted to hold said medium, partitions therein to form a fire-chamber having upper and lower portions, a gas burner in said fire-chamber, a smoke pipe, a direct discharge thereto from the upper portion of said fire-chamber, a secondary heat exchanger chamber below the firechamber having a multiplicity of heat exchanger members therein, a blower for drawing the gases of combustion from the upper portion of the fire-chamber through said heat Exchanger members and discharging them to the stack, and a damper operated by said blower to close the first connection and open connection from the blower to the stack.

6. A heating device, comprising a fire-chamber, heat-exchanger tubes connected therewith and having. connection with the stack for carrying oli the gases of combustion, part of the travel of said gases being downward a suction blower for moving the combustion gases, 2. gas burner in said fire-chamber, a normally-closed valve for supplying gas to the burner, a valve for supplying secondary air to the burner, an electric motor for operating said first-named valve, an electric motor for simultaneously operating said suction blower and connections between the two valves whereby the operation of the gas valve will open the secondary air valve.

7. A furnace comprising a primary heat shamber and a secondary heat chamber separated therefrom, each containing a multiplicity of spaced tubes, the tubes in the primary heat chamber being positioned substantially vertical, the tubes in the secondary heat chamber being positioned substantially horizontal and occupying substantially the entire cross-sectional area of said secondary heat chamber, means for causing the gases of combustion to pass through the vertical tubes first and thereafter the horizontal tubes, and means for determining the flow of a heating medium constraining it to flow about the horizontal tubes first and then the vertical tubes and thereafter to the rooms.

8. A furnace comprising a primary heat chamber and a secondary heat chamber separated therefrom, each containing a multiplicity of spaced tubes, the tubes in the primary heat chamber being positioned substantially vertical, the tubes in the secondary heat chamber being positioned substantially horizontal and occupying substantially the entire cross-sectional area of said secondary heat chamber, and being bent intermediate their ends to form aplurality of spaced parallel layers of said tubes, means for causing the gases of combustion to pass through the vertical tubes first and thereafter the several layers of horizontal tubes, and means for determining the flow of heating medium through said layers ,and about the horizontal tubes first and then about the vertical tubes and thereafter to the rooms.

9. In a furnace, a fire chamber, means for delivering and burning fluid fuel toward the bottom thereof, a conduit leading from the fire chamber directly to the stack, a valve box in said conduit, a heat exchanger conduit leading over a tortuous path to said valve box, a normally open valve for closing the first-named conduit, a blower in the second-named conduit operative to cause the gases of combustion to move therethrough, and means operated by said moving stream of gases for closing said valve.

10. A heating device employing steam or hot water as a heating medium comprising a casing forming a fire-chamber having upper and lower portions connected by heat-exchanger passageways, and a heat-exchanger chamber below the fire-chamber of the entire cross-sectional area of the casing, a multiplicity of horizontally-extended heat exchange tubes in said lower chamber, means conducting the return water directly into said lower chamber, a vertical passageway of generally rectangular cross-section formed in said casing and opening directly into the upper portion of the fire-chamber and connected at its lower portion with said heat-exchanger tubes for conducting the gases of combustion to said tubes, and means to cause said gases to move through said conducting means and tubes and discharge to the stack.

11. A heating device employing steam or hot water as a circulating medium, comprising a casing forming a fire chamber having upper and lower portions, the lower portions spaced from the bottom of the casing to form a heat exchanger chamber below the same and the upper portion spaced from the lower portion and connected therewith by heat exchanger passageways to form a heat exchanger chamber between said portions, said heat exchanger chambers and connections being entirely within the limits of the casing, a multiplicity of sets of horizontally-extended hotgas conveying heat exchanger passageways in said lower heat exchanger chamber adapted to pass gases of combustion horizontally in both directions across said lower chamber, with fins formed on the walls of said passageways providing a multiplicity of vertical passageways substantially surrounded with heat exchange surfaces between said sets adapted for the flow of said heating medium therethrough, means for conducting the gases of combustion to said lower passageways, and means to cause said gases to move therethrough and discharge to the stack.

FRANK A. WHITELEY.