US2447902A - Fuel control for hot-air heaters - Google Patents

Description

Aug. 24, 1948. R. w. DE LANCEY v I I FUEL CONTROL FOR HOT AIR HEATERS Filed Nov. 1a. 194:

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Patented Aug. 24, 1948 FUEL CONTROL FOR HOT-AIR HEATERS Ralph W. De Lancey, Meriden, Conn., assignor to The Miller Company, Meriden, 001111., a comicration of Connecticut Application November 13, 1943, Serial No. 510,183 19 Claims: (01. 126-110) The giresent invention relates to fuel control valves for liquid fuel burners, and is more par,- ticularly directed toward combined constant level and metering valves for gravity fed liquid fuel burners.

The present invention contemplates a metering valve in which the'valve stem when free of restraint is biased toward open position, and wherein a manually operable device, such as a lever, may be moved against spring tension from a position where it overpowers the valve stem biasing means and forces thevalve to closed position to a burner operating position where it releases the valve stem for movement toward open position. A high fire stop is provided toli-mit the movement of the valve stem toward open position. The manually operable device-is prefer:

ably latched in running or operating position against spring pressure so that when released the valve stem is forced to closed position.

.-"'.'Ihe release of this latch may be employed in the routine operation of shutting down the burner. The limiting of the opening of the metering valve to amounts less than the maximum may, if desired, be accomplished by mechanism such as shown and claimedfin my U. S. Patent No. 2,428,867, dated October 14, 1947.

The present invention also contemplates the provision of. thermal responsive means close to the burner and preferably in the path of the forced draft for the burner which acts on excessively high temperature to release the latch and therefore shut down burner operation.

The level of the liquid in the constant level valve chamber may be controlledby any suitable form of liquid level responsive mechanism. Where such valves are employed in portable devices there is a tendency for the liquid level responsive mechanism to move about, whether liquid is in the chamber or not and the inlet valveis subject to wear and the likelihood of being opened when no fuel is wanted, thereby causing leakage.v To overcome these difflculties the present invention \contemplates means for insuring the closing of the rinlet valve and the holding of the float or liquid level mechanism stationary atall times when the metering valve is closed.

While the float valve control and the metering valve control to be described herein may be used separately or in combination with common parts, they are also suitable for use with the thermal control to effect a simultaneous closure of both valvecontrols. A portable warm air heating furnace, wherein these parts are especially suitable for use, is shown in my application, Serial No. 510,181 filed November 1943. 7.

Other and further objects will hereinafter appear as the description proceeds.

- able hot air heating furnace to which the controls (shown inrunning position in full lines and in shut-off position in dot-and-dash lines) are applied, the fuel burner and combustion chamber being in section on the line i-l of Figures 3 and 4;-

Figure 2 is an enlarged elevational view of the burner and valve controls also taken from the rear of the furnace and showing the starting control in running position and the thermal control in various positions of adjustment;

Figure 3 is a horizontal sectional-view on the line 8--3 of Figure 2;

Figure 4 is a vertical sectional view on the line 4-4 of Figures 1, 2 and 3, the float and metering valves being shown open;

Figure 5 is a fragmentary vertical sectional view on the line 5-5 of Figure 3;

Figure 6 is an enlarged vertical sectional view on the line 6-6 of Figure 3 showing the metering valve closed;

Figure 7 is a fragmentary view similar to Figure 6 showing the metering valve open;

Figure 8 is an elevational view of the valve operating mechanisms in the open or running position and taken in the direction of the arrow 8 in Figures 1, 2, 3, and 6; and

Figure 9 is an elevational view of the operating mechanism taken from the right of Figure 8.

The bottom housing unit A of the portable hot air heating furnace has a semi-cylindrical bottom housing member 20, to which is welded a tubular burner housing M. This burner housing extends below the bottom housing member 20 as indicated at Ila (Figure 1) and above it as indicated at Ill). The unit A also has legs 22 for support.

The, combustion drum C has an outer cylindrical body 24, and end walls 25 and 26. These end walls have aligned openings 21, which receive air tubes 28. The bottom part of the drum body 24 is provided with an opening 29 in which I 3 is welded a downwardly extending fire tube near one end of the combustion drum and concentric with tube 2|. The adjacent wall 20 of thecombustion chamber supports an inverted bog like baiiie 3i which protects the adjacent ends of the air tubes 28 from direct impingement of the flame and yet permits the heat to pass out about these air tubes. The combustion drum is provided with a stack opening 82 at the top and at the end opposite the fire tube 30. The upper edge of the tube 2I engages the lower surface of the drum 24 in the side away from the end. wall 25 so as to provide an opening 21 for' a blower whose fan is indicated at M and this blower acts to force air through the space between the combustion drum and housing and the tubes 28, as well as air for combustion through opening 81. 1 1A; cap? for the staclr fits on the outer end of the stack and may eithenbeplaqed lathe stack or hung free by means of the chain shown. When the cap is in the position indicated the products of combustion pass out'through the staclnbuhwhen it is placed on the end oi the stack the products of combustion do-not pass out through the stack. In order to permit the products of combustion to escape from the drum without going up the stack, the end wall 20 of the drum is provided with flanged opening 46 adapted to receive and support a reversible plug G. When the plug is in the position shown it compels the products of combustion to go up through the open stack. When, however, the plug G is withdrawn, reversed end for end and reinserted the products of combustion may pass through the hole 48' in the stamping l8 and enter the plug. The air delivery cover H shown herein is one adapted to receive a duct, usually of fabric, for conducting air to the region to be heated. It serves to receive the air blown through the combustion drum and the space between the combustlon drum and the housing, as well as the contaminated air when the plug G and the cap F are in proper position for delivering contaminated air.

The fuel supply tank I delivers fuel to the strainer J through pipes, one of which is shown at 62, The discharge pipe from the strainer is indicated at 66 and it leads into the fuel control valve formed in part of the burner control valv unit B.

termined supply of fuel in the float chamber H. The casting I0 is provided with an outlet valve seat insert I0 at the bottom of the float chamber, which cooperates with a metering valve stem I8 urged upwardly by a spring 80 and downwardly by mechanisms to be described. This valve forms 7 the metering valve for the burner.

The constant level valve and metering valve are under manual control for the purpose of starting and stopping the burner and are under automatic control for the purpose of emergency shutdown of the burner as well as for the continuous control of the metering valve for normal continuous operation. These controls will now be described.

The starting lever for opening the fuel line into the fuel chamber II is shown at 8I. It is pivoted at 82 to the U-shaped stamping 82' carried by the cover member and-has a generally horizontally extending arm 83, which overlies the top of the cover member I2. When it is in the position shown in Figures 1, 2, 3, 4, 7, 8 and 9, the inner end of this arm 83 is latched in this position by a lever 84- pivoted at 85 .to the stamping 82' and having a rearextenslon 80,

When the starting lever 8| is latched in this normal operating .position,'.,=the arm 83 presses down on a pin 81 which extends through the float chamber cover I2 and normally rests on the top of a leaf spring 88. This leaf spring iscarried by the under side of the cover I2 and is normally urged upwardly. It is arranged as shown in Figure 4 to be free of the float mechanism when in that position, but when the starting lever 8i is in the shut off position, as indicated in dot-anddash lines in Figure 1 and in full lines in Figure 6, the pressure on the leaf spring 88 is removed and this spring is able to act on the float mechanism, so as to move it into the position to move the valve I5 to closed position and at the same time it will lock the float mechanism against vibration during shipment or transportation of the burner.

The starting lever, 8I has a cam 89 adapted to act on a lever 90 pivoted to the stamping 82' at 8| and urged downwardly by a coiled spring 92. The lever 90 carries a leaf spring 93 whose position can be adJusted by high fire adjustment screw 94. The free end'of the spring 93 extends above shoulder 95 on the valve stem I9 and is choking on of the draft by simultaneously closing The body casting of the burner valve control 5 unit B is designated by the reference character I0. It has a float chamber Ii which is closed oil by a cover 12, fastened in place by screws I2. The cover has a rearwardly extending tubular coupling element I3 for coupling to the fuel line 66. A valve seat member I4 is threaded up into a drilling It, in the cover member I2 and this valve seat member 74 receives a valve pin 15 which is normally controlled by a float I6 hinged at 'II. When the parts are in the position shown in Figure 6 the float'IIi and float control valve I5 operate similarly to the float valve in an automo-,

.bile engine carburetor and maintain a predethe stack and the delivery end of the combustion chamber, or by the stoppage of delivery of contaminated air from the furnace, there is the possibility of continuation of burner operation without proper draft which would bring about overheating near the burner and sooting of passages. To avoid such operation the furnace is provided with a bimetallic safety device N having a resilient bimetallic thermostat 90 supported from a bracket 91 in the space between tubes 2| and 30 and having an extension 98 engaging notched element 99 on the rear of latch lever 84.

The bracket 91 is part of a plate I00 held in place on tube 30 by screws I00. A shaft IOI threaded into bushing I02 is provided with a yoke I03 to receive the bimetallic member 96 and a handle I04 by which the thermostat may be adjusted to respond to dangerous temperature rises above varying'ambient temperatures-such as -45 F.

or room temperature. Buitablestops Ma and lb limit the movement of handle I04. On overheating the thermostat 9B expands and releases the starting lever 8i causing the float valve and metering valve to close.

When the starting lever 8| is shifted to open the valves and the furnace is cold, the metering valve will open to an extent determinedby theair temperature control unit L in amanner to be described below. The fuel will then be allowed to flow through the metering valve at a predeter-- mined rate which is the proper rate (more than pilot and less than maximum fire) for startin the burner. The fuel will pass down a sloping passage I05, see Figure l, and enter the vaporizer illt, forming the other end of the body of the burnert unit B. The burner construction which forms the subject matter of concurrently filed application Serial No. 510,182, new Patent No. 2,432,143, issued December 9, 1947, will now be briefly described.

The vaporizer I08 has a central air tube I01 and a row of downwardly andinwardly extending air holes or drillings I08. The vaporizer carries a perforated sleeve I09, preferably having larger holes at the top than at the bottom and this sleeve is clamped in position by a ring H0 and bolts iii. The ring III] is just the proper size to fit into the fire tube and this tube is provided with a bead I I2to provide a stop for the ring. The ring is provided with perforations II3, shown more clearly 'in Figure 3, and carries upwardly extending rods H4 which support a flame spreading plate H5. The ring IIO also carries a. downwardly and outwardly flaring skirt II6 which terminates just above the top of the vaporizer 106. The skirt compels the air to pass underneath it to where air is preheated. This skirt also acts to prevent flame from passing out through the sleeve I09 and up the tube 2|. The bottom of the vaporizer I06 is covered by the cup shaped stamping II1 to providean air space H8 and facilitate maintaining the vaporizer at a high temperature.

The unit B for the burner and fuel valve assembly i supported from the tube 2| by screws iI9--I I9 which pass through holes in the tubes 2I' and 30 and are threaded into ring H0 and by screws I20 which pass through holes in a bracket I2I welded to tube 2I and are threaded into the casting 10.

The bottom of the down draft tube 2| is closed off by a hemispherical stamping I22, which fits into the ring I 23 carried by the bottom of the tube 2i and it is removably held in place by screws I24 threaded into ring I23. The casting 10 has a constriction as indicated at I25 which impedes the flow of heat lengthwise of the body member 10. As shown more clearly in Figure l, the riser or air tube I01 receives a ring I26 which carries a number of fingers I21 of heat resistance wire of good thermal conducting material.- These fingers it first allows the metering valve to open for maximum fire and then as heating continues proceeds to cut down the fire to a low flame. As the furnace cools the firing rate is raised. The intensity" of the flre,'therefore, varies between the maximum and minimum, so that there is no likelihood of overheating the parts, or delivering the air at too high a temperature, or of extinguishment of the flame.

It will thus be seen that when the structure is cold or at ordinary room temperatures the extent of opening of the metering .valve will be controlled by the adjustment of the stop mechanism for the air temperature responsive thermostat, and that when the starting lever BI is moved to the starting position the fuel line will be opened to the float chamber, and fuel at a predetermined flow rate will pass down to the burner. This fuel will form a, pool in the burner and must be immediately lighted. If for any reason the metering valve is allowed'to remain open too long before the torch is supplied, the oil can flow from the vvaporizer out through the tube I01 and escape through a drain hole I22 in the stamping I22.

extend up into the combustion space and carry heat down into the bottom of the vaporizer. A lighting tube [30 is carried on the front side of the furnace and extends through down draft tube 2i and the fire tube 30.

A reciprocating rod or slider I49 is operated upon by an air temperature responsive thermostatic apparatus I4 I' shown more fully in theapplicatlons above referred to, but for present purposes it is believed sufllcient to say that when the apparatus is cold the bracket member I5I carried by slider I49 is brought to a positionwhere it limits the opening of the. metering valve stem to The lighting can be done by inserting a torch through the lighting tube I30. The fuel will be consumed in the burner; and the natural draft caused by the combustion of the fuel will cause th products of combustion to pass up through the combustion drum, and air will be drawn in through the down draft tube 2I. When the burner has been heated by natural draft sufficient to permit forced draft operation, the motor or engine may be started so as to operate thefan and blow air through the furnace and throughthe burner.-

' Since it is obvious that the invention may be embodied in other forms and constructions within the scope of the claims, I wish it to be understood that the particular form shown is but one ofthese forms, and various modifications and changes being possible, I do not otherwise limit myself in any way with respect thereto.

What is claimed is:

. 1. In combination, a gravity fed liquid fuel burner, a flue above the burner for products of combustion, a down draft tube about the flue for supplying air to the burner, a fuel chamber above the level of the burner and disposed laterally of the down draft tube, an outlet valve in the fuel chamber, means biasing the outlet valve toward open position, a fuel passage between the outlet valve and burner, an inlet valve for the chamber, liquid level responsive mechanism for controlling the inlet valve, a spring actuated outlet valvev mined temperature to release the latching means whereby both valves are closed.

2. In combination, a gravity fed liquid fuel burner, a flue above'the burner for products of combustion, a down draft tube about the flue for supplying air to the burner, a fuel chamber above the levelof the burner and disposed laterally of the down draft tube, an outlet valve in the fuel chamber having an upwardly projecting valve stem and a spring urging the valve stem upwardly, a fuel passage between the outlet valve and the burner, an inlet valve for the chamber, liquid level responsive mechanism forcontrolling the inlet valve, a spring actuated lever engageable with the outlet valve stem for closing the valve, a spring actuated float lifter for closing the inlet valve, a manually movable member for disengaging the lever from the valve stem and the float lifter from the float whereby they are free to move, a latch for securing the manually movable member in said disengaged position, and a thermo-' static element in the down draft tube effective on reaching a predetermined temperature to release the latch whereby both valves are closed.

g 3. In combination, a gravity fed liquid fuel burner, afuel chamber disposed above and to one side of the burner and connected to it by a fuel passage, a metering valve in the fuel passage and having an' upwardly urged valve stem, a cover for the chamber through which the valve stem Dr trudes, a float operated inlet valve for controlling flow of liquid into the chamber, a cover sup ported element-spring biased to movethe metering valve stem to closed position, a cover supported, manually operable device for shifting said element to tension its spring, a cover supported latch for said device, a resilient. thermal element acting as a spring for the latch and disposed adjacent the burner andeii'ective on reaching a predetermined temperature to release the latchand permit said element to close the metering valve.

4. The combination claimed in claim 3, wherein the cover carries a float lifter biased to lift the float and close the inlet valve'when the manually operated device is unlatched and shifted to .free the float when said device is latched.

5. In a portable, gravity fed, liquid fuel operated heater, a fuel supply tank, a float chamber, a fuel passage between the tank and chamber, a float valve in the chamber for controlling the flow of fuel into the chamber and maintaining a substantially constant level therein, a vaporizer below the chamber, a fuel passage between the chamber and vaporizer, a metering valve controlling flow from the float chamber to the vaporizer, a manually operable member biased to one position and latchable in another position, and devices operable by said manually operable member for closing both the metering valve and the float valve when the member is unlatched and releasing both valves when the member is latched whereby fuel may flow into and out of the chamber in accordance with the valve positions.

6. In a portable, gravity fed, liquid fuel operated heater, a fuel supply tank, a float chamber, a fuel passage between the tank and chamber, a float valve in the chamber for controlling flow of fuel into the chamber and maintaining a substantially constant level therein, a vaporizer below the chamber, a fuel passage between the chamber and vaporizer, a metering valve controlling flow from the float chamber to the vaporizer, a manually operable member biased to one position and latchable in another position, devices operable by said manually operable member for closing both the metering valve and the float valve when the member'is unlatched and releasing both valves when the member is latched whereby fuel may flow into and out of the chamber in accordance with the valve positions, and a thermostat adjacent the burner and effective on reaching a predetermined temperature to release the latch.

7. The improvement in fuel flow regulation valves having a float chamber with an inlet and an outlet, a float controlled inlet valve, a metering valve controlling flow through the outlet and biased toward open position, which comprise a spring actuated inlet valve closer, a spring actuated metering valve closer, and a latchable deviceacting on both valve closers to stress the springs thereof so that the valves may open to allow flow of fluid and acting when unlatched to release both closers to stop flow and hold the mechanisms of both valves immobile.

8. In a device for regulating fluid flow from a. chamber wherein it is maintained at a substantially constant level, an outlet passage having an upwardly facing valve seat, a vertically movable valve stem biased upwardly by a valve opening spring, a vertically movable member having a stop against which the spring urges the valve stem, 9. spring acting on the vertically movable member to urge it toward the valve stem and overpower the valve openin Spring, a. reciprocatory member having a cam which in one position lifts the vertically movable member and stresses the spring acting on the same, and a latch for securing the reciprocable member in the latter mentioned position, the said reciprocatory member on being unlatched shifting the cam to a positionto release the vertically movable member to close the valve.

9. In a device for regulating fluid flow from a chamber wherein it is maintained at a substantially constant level, an outlet passage having an upwardly facing valve seat, a vertically movable valve stem biased upwardly by a valve opening spring, a cover through which the valve stem protrudes, a spring biased presser member pivoted on the cover and when released acting on the valve stem to move it to closed position, the presser member pivoted on the cover and carrying a stop which limitstheopening movement of the valve stem, 8. cover supported, oscllTctolycalnj-for lifting the presser member away from thevalve stem so that the valve may open, and a cover supported latch for the cam.

10. In a fuel controlling valve, an upwardly opening chamber having a centrally disposed upwardly facing outlet valve seat, a cooperable outlet valve stem extending'upwardly above the top of the chamber, a spring biasing the valve stem away from the seat, a cover for the chamber having an opening through which the valve stem protrudes, a fuel supply connection carried by the covenand leading to a downwardlyfacing inlet valve seat, an inlet valve stem movably carried by the cover, a float movably carried by the cover and when released cooperative with the inlet valve stem, an arm pivoted to the cover to move about a horizontal axis and biased downwardly against the outlet valve stem to move it to closed position, a float lifting spring carried by the cover which when released closes the inlet valve, and cover carried means for simultaneous- 1y releasing both the inlet and the outlet valve controls so that said valves may open or for simultaneously closing them so that fuel flow through each valve is prevented. v

I 11. A valve such as claimed in claim 10, having a spring controlled latch for holding said means in valve opening position.

12. A valve such as claimed in claim 10, having a resilient bimetallic. thermostat for holding said means in valve opening position and movable on heating of the thermostat torelease said means.

13. A liquid flow regulating valve having a float chamber, a chamber cover having an inlet valve, a float in the chamber for controlling the opening and closing of the valve in accordance with fluid level, a float lifting springcarried in the float chamber and biased to lift the float and close the valve irrespective of liquid level, a plunger extending through the cover and engageable with the spring to free the float, and a latched member for operating the plunger.

14. In a fuel flow regulating valve adapted for variable flow control by an extraneous operator, a valve stem biased toward open position, a presser member spring biased to act on the valve stem and move it to closed position, an actuator for the presser member spring biased to a position to free it from restraint by the presser member and manually operable to a position to move the presser member out of controlling relation with the valve stem, and a releasable latch to secure the actuator in the latter position so that the valve stem may be moved back and forth by the extraneous operator, the latch when released releasing the presser member to close the valve.

15. A valve such as claimed in claim 14,.wherein the presser member carries an adjustable stop which limits the opening movement of the valve stem.

16. The combination with a gravity fed liquid fuel burner'having a vaporizing pot and an imperforate wall above the pot to provide a combustion chamber, of a safety control for the fuel supply thereof, comprising a valve through which fuel flows to the burner when the valve is open, valve opening means, latch controlled spring actuated valve closing means effective when unlatched to overpower the valve opening means and close the valve, a resilient bimetallic element holding the latch in latching position when cool, the

bimetallic latch holding element being closely adjacent the combustion chamber wall so as to be subject to radiant heat therefrom, and forced draft producing means to supply air to the burner and arranged to blow cold air on to the bimetallic element tokeep the element cool and in latching the stem of the metering valve so that it may open and acting on release to close the valve, and a 4 thermostat connected to the latch to normally hold'the latch closed, the thermostat being placed in a region adjacent th burner normally maintained cool by the forced draft but subject to radiant heat from the burner and undergoing such a rise in temperature when draft conditions for the burner are adversely affected as to bring about a release of the latch.

18. In combination, a liquid fuel'burner which produces hot combustion products, a vertical tubular fine for the combustion products, a concern tric down draft tube to supply air to the burner from below, means for supplying forced draft to the top of said down draft tube, a control valve biased toward open position for supplying fuel to the burner, valve closing means, means for latching the valve closing means in a position where itis ineffective to close the valve, and a bimetallic thermostat in the down draft tube and adjacent the fine so as to be subject to radiant heat therefrom, but being normally maintained cool by the air supplied through the draft tube, and thermostat operated means acting on the attainment of a predetermined higher temperature to release the latching means to unlatch the valve closing means.

19. In combination, a blower, a gravity fed, liquid fuel fired burner operated by forced draft from the blower and having a combustion chamber formed by a wall adapted to be heated by the burning fuel, means forming a down draft air passageway about the wall and normally cooled by the draft air, a hot air heater operatlvely connected with the combustion chamber and supplied with ventilating air by the blower, and means normally preventing overheating of the burner comprising a, bimetallicthermostat in the air passageway and normally kept coolby the air therein, a fuel supply valve controlled by said thermostat. the thermostat being closely adjacent the combustion chamber wall so as to be subject to radiant heat therefrom and effective on overheating to close said valve.

RALPH W. DE LANCEY.

naraaancas crrnn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number- Landon et al. Dec. 21, 1943

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