US1791181A - Liquid-fuel burner - Google Patents

Description

Feb. 3, 1931.

E. F. WHITE LIQUID FUEL BURNER Filed Aug. 15. 1926 2 Sheets-Sheet l Feb. 3, 1931. E. F. WHITE 1,791,181

LIQUID FUEL BURNER Filed 1926 2 Sheets-Shoot 2 Patented Feb. 3, 1931 UNITED STATES EZEKIEL FJWHITE, O1 HARTFORD, CONNECTICUT LIQUID-FUEL BURNER Application filed August 13, 1926. Serial No. 129,083.

This invention relates to liquid fuel burners'and comprises improvements wherebythe burner may be automatically cut'out of operation in case conditions arise preventing its normal functioning.

The invention will be best understood by reference to the following description when taken in connection with the accompanying v illustration'of one specific embodiment there- 1 0 of, while its scope will be more particularly pointed out in the appended claims.

In the drawings, Fig. 1 is a sectional elevation illustrating those parts of the-burner apparatus which are located in or adjacent the combustion chamber of a boiler or other heater;

Fig. 2 is an enlarged detail of the thermostatically operated air valve shown in Fig. 1; Fi 3 is a sectional elevation taken through the uel supply chamber located exteriorly of the boiler and illustrating the associated fuel control devices; and

Fig. 4 is a detail in plan showing the float and the levers associated with and control- I ling the fuel admission valve.

Referrin to the drawings, I have there shown for illustrative purposes one embodiment of the invention as applied to a burner of the general type illustrated in my prior Patent No. 1,593,231, dated July 20, 1926. It

is to be understood, however, that the features of control herein described are applicable to burners of other and widely differing types from that herein shown. In the following description, for simplicity, the liquid fuel is referred to as oil, but it is to be understood that the described apparatus is adapted for use with liquid fuel broadly, unrestricted to any particular kind.

Referring to the drawings in detail, and first to Fig. 1, the burner is shown applied to a heater 11 of any conventional type, such as a hot water or steam boiler. Within the combustion chamber 13 of the heater there is located the burner nozzle 15 mounted on the top of an upright hollow rotatable shaft 17, through wh1ch atomized or finely divided liquid fuel is discharged, producing, when ig-- nited, a burner flame in the form of a thm uniform sheet diverging in all directions from the nozzle orifices. An auxiliary supply of air is fed to the combustion chamber about the burner nozzle through baflled air passages formed by the grid-like structure 19 in the bottom of the combustion chamber and comprising a series of superposed rings and baflle plates. I

The burner nozzle is rotated at a high rate of speed by means of the electric motor. 21 mounted on an upright axis inthe underlying working chamber 23 of the heater, the motor being also connected to drive the underlying pump 25, preferably, though not neces sarily, a gear pump of the positive displacement type. The motor casing is supported on the ump casing and the latter rests on a suitable support in the bottom of the heater, such as is afforded by the cushioning springs 27.

In the operation of the burner, liquid fuel, such, for example, as oil, is drawn by the action of the pump from an oil supply chamber through the feed or suction pipe 29 of the pump, the-same being comingled more or less with air or other gaseous fluid. The oil drawn into the pump is further atomized or comingled with the accompanying gas and discharged by the pump under pressure from the burner orifices through the hollow upright shaft 17 which passes through the armature of the motor androtates therewith. A pilot light 31 of any suitable type is provided to ignite the burner flame whenever the burner is started into operation.

The motor connections pass through the 35 cable 33 and the motor, and therefore the burner, may be stopped and started by any of the usual thermostatically controlled switches which are customarily used with this class of liquid fuel burners, the burner being started into or cut out of operation automatically as conditions require.

Referring now more particularly to the devices for supplying the comingled air and oil to the pump, the oil supply reservoir, which is preferablylocated outside of but closelyadjai cent the heater, comprises a constant-level, oil-su ply chamber 35, to which fuel is admitte from a tank or other main reservoir through the supply pipe 37 the strainer 39 and the feed chamber 41. The oil passes from the feed chamber 41 to the supply chamber 35 through the feed passage 43, its pas-.

sage being regulated by the cut-off or control valve 45. e

During the normal operation of the burner, as will he hereinafter explained, a constant predetermined level of the oil is maintained in the supply chamber 35 by means of the float 47, the oil being withdrawn through the the tube through the orifice 53, the latter communicating with the air conduit 55'located above and outside of the oil reservoir and COD? nected with any suitable source of air or other aseous fluid, which is preferably heated beore being admitted to the conduit 55.

The oil orifice 51 and the air orifice 53 may be controlled in any-desired way to vary both the actual and relative amount of air and oil fed to the burner, there being herein provided for such a purpose the sleeve 57 rotatably mounted on the tube 49 and provided with apertures adapted to register with the orifices 51 and 53. The sleeve may be turned and adjustably set in any desired position by any suitable means, such as the exteriorly arranged disk-like thumb piece 59, so connected to the sleeve that the relative amount of air and oil fed may-be adjusted as desired.

Referring now to the actuation of the oil control or cut-ofl' valve 45, the latter is so controlled by the float 47 that'it is permitted to open only when the oil level drops and the float descends below the position had at the normal or predetermined level of the oil. The valve, however, is positively closed by the action of the float as soon as the oil rises to its normal or predetermined level. The float, however, is so related to the oil valve that while its upward movement serves positively to close the valve, its descent does not positively open the valve, the latter being allowed to openin response to the descent of the float only while the burner is properly functionin K. Tor this purpose, opposite sides of the float (Figs. 3 and 4) are connected to the two branched lever arms 61 which are pivoted at their opposite and converging ends to the bracket 63 resting on a suitably formed base in the walls of the reservoir. To cause the valve to close when the float ascends, while cerned, to open or close'when the latter descends, there is provided a second lever 65 one end of which is pivoted at 67 between the forked upper ends of the valve stem 69. The opposite end of the lever 65 carries a Weight or counterbalance 71 which rests loosely on the float arms 61, the lever having a pivotal axis intermediate its ends, herein coincident with the axis of the float lever. Accordingly, if the float rises it lifts the weighted end of thelever 65, depressing the opposite end thereof, and serving to positively close the valve 45 when the oil has risen to a sufficient height in the reservoir. When the oil level drops and the float descends, the

weight tends to follow the float lever down and to open the valve to replenish the oil supply, unless the opening of the valve is interfered with by the supplemental control hereinafter described, in which event the float may descend, withdrawing the lever arms 61 from the counterweighted lever and leaving the latter undisturbed.

trolled by a pin or plunger 73 which, when depressed, is adapted to rest on the end of the counterbalanced lever 47 above and in line with the valve stem 69. The pin 73 is connected to the weighted piston 75 vertically slidable within the cylinder 77. The arrangement is such that when the piston is raised within the cylinder 77, the control valve is under the exclusive control of the float 47, opening and closing as the oil level lowers or rises and permitting the float so to regulate the flow of oil as to maintain a substantially 'constant oil level. When the piston descends in thecylinder, however, the pin 73 is caused to engage the end of the lever 65, forcing the latter down and causing the oil valve positively to seat. This acts to cut off the further supply of the oil to the oil reservoir, irrespective of any further movements of the float, until the piston is again raised and the pin 73 withdrawn from the lever. 1 1 v I Any suitable means may be employed "for raising and controlling the piston, but herein connections are provided between the cylinder 77 and the pump 25 so that under proper conditions a vacuum is established in the top of the cylinder and the weighted piston caused to move to and remain in the upper part of the cylinder. In the normal operation of the burner, such vacuum is maintained so long as the pump'is in operation, but means are also provided whereby the vacuum may be destroyed if the normal functioning of the burner is interfered with, thereby causing the weight to drop and the oil valve to close.

In the illustrative form ofthe invention, to make the pump effective in lifting the piston, a connection in the form of a vacuum pipe 7 9is maintained between the feed or suction leaving it free, so .far as the float is conpipe 29 of the pump and the upper end of the cylinder 7 7 In the normal operation of the burner, as soon as the pump is started into Herein the oil valve is additionally conoperation the suction of the pump acting through the pipe 79 produces a vacuum in the upper part of the cylinder of sufficient amount to cause the piston to rise and remain lifted, freeing the oil valve for full control by the float. When the pump stops, the vacuum ceases, the piston descends and the oil valve closes.

To out off the oil supply from the oil reservoir in case of the failure of the burner to normally function, as through extinguishment of the pilot light, failure to deliver the necessary oil supply at the burner orifice, or through the creation of any condition causing the failure or a substantial dimunition of the burner flame, thermostatically controlled means are provided exposed to the heat of the burner so that on the failure of the burner flame to generate the necessary amount of heat, the weighted piston is allowed to descend, cutting off the supply of oil.

For this purpose there is provided a thermostat in the combustion chamber, operatively related to the heat of the burner flame and serving to control an air valve, the latter functioning to destroy the pump-created vacuum in case the burner fails to create the normal amount of heat. Any suitable form of thermostat may be used, but herein" (see Figs. 1 and 2) there is provided a sensitive thermostatic diaphragm 81 constructed of two disks of metal welded together as a single piece. The metal on the lower side of the diaphragm has a relatively low coefiicient of. expansion and that on the upper side a relatively high coefficient of expansion. The diaphragm is located near the bottom of the combustion chamber and is supported at its edges by the upper end of an upright conical shell 83. The latter provides an air supply passage from the working chamber to the combustion chamber, the air entering the shell through the lower lateral supply orifice 85 and passing out into the combustion chamber through the'upper discharge orifices 87. The diaphragm 81, which is positioned substantially longitudinally, accordingly has its upper side exposed to the heat of the combustion chamber generated by the burner flame, but its under side exposed to the relatively cool air supply passing through the shell 83, so that on the cessation of the burner flame it undergoes a rapid lowering in its temperature. This materially increases the sensitiveness of the thermostat, and the re sponsiveness of the valve controlled thereby, to the presence or absence of the heat from the burner flame. It has been found in practical operation that a thermostat constructed as illustrated can be made to shut off the oil valve within ten seconds after the burner flame is extinguished.

To control the oil valve the diaphragm is centrally connected by a small depending rod 89 to an air valve 91, preferably by a lost motion connection. The air valve, during the normal operation of the burner, and while the thermostat is subjected to the flame of the burner,is adapted to rest against-a valve seat formed by the lower edge of a tube 93 which extends upwardly into the conical shell 83 about the rod 89, there being provided however a clearance space between the rod and the inner walls of the tube, there by forming an air passage about the rod communicating with the air supply within the shell. During the time that the valve remains seated, such air passage is closed by the valve. In the event of failure of the. burner flame, the diaphragm, as quickly as it cools, tends to bow or bend downwardly, depressing the rod 89, causing the valve 91 to unseat and opening the air supply to a pipe 95, which I latter communicates (see Fig. 3) with the upper end of the cylinder 77. I

Accordingly, so long as the burner flame persists and the valve remains seated, there is no interference with the vacuum created in the upper end of the cylinder 77 by the operation of the pump 23. In the event the burner flame fails, however, the diaphragm is thereby moved to unseat the valve, the upper part of the cylinder 77 is opened to the air through the pipe 95, the tube 93 and the shell 83, and the vacuum can no longer be maintained therein, whether or not the pump is in operation, thereby causing the weighted piston to drop and the oil valve to close.

To provide a lost motion connection between the diaphragm actuated pin and the valve, the latter has a tubular stem 97 which has a frictional telescopic-connection with the lower end of the pin 89. The downward or opening movement of the valve is limited by the limiting pin 99 and the movement of the diaphragm is greater than that which is necessary to open and close the valve. The

first movement of the diaphragm following 4 the extinguishment of the burner flame, therefore, opens the valve, bringing it to rest against the pin 89. Further movement of the diaphragm merely causes a slippage between the pin 89 and the tubular valve stem 97. On the opposite movement of the diaphragm the pin 89 is lifted, immediately seating and closing the valve, further movement of the diaphragm merely resulting in aslippage in the opposite direction between the pin- 89 and the tubular valve stem. I

As a further supplemental and cooperating control for the described apparatus, means are provided so that in the event the, float descends to a predetermined level, as, for

example, by reason of the exhaustion of the' oil in the oil supply chamber 35 or by reason of the puncturing and sinking of the float, the motor circuit may be opened and the further operation of the burner stopped. For this purpose there is provided in the motor cirwithin the casing 107' above the reservoir.

chamber and carries the lever arm 109 which projects through an aperture in the top of the reservoir casing andrests on the float 47.

When the float is elevated to a position corresponding to the normal oil level in the reservoir ;(as, for example, that-shown by full lines in Fig.3) it presses upwardly against the lever arm 109, tipping the tube 101 to a position where the circuit terminals 111 are electrically connected by the small amount of mercury 113 which is maintained within the tube 101. If the float descends to an abnormal position, however, such as is represented by a substantial exhaustion of oil from the supply reservoir, or such as might occur from a puncture or defect in the float (for example, see dotted line position of float in Fig. 3), the pressure is relieved on the lever arm 109 and the latter descends,'allowing the tube 101 to gravitate and tip about the pivot 105, the mercury flowing to the opposite end of the tube and opening the motor circuit at the contacts 111. This results in the immediate stoppage of the motor and the pump, and

the extinguishment of the burner flame, WlllCll in turn causes the opening of the air valve, the lowering of the weighted piston and the closin of the oil supply valve.

In t normal operation of the burner, the motor and pump are caused to start and stop as required by the control of the room thermostat, the burner flame persisting so long as the motor circuit is closed and the pump continues to supply oil from the float-controlled, oil supply reservoir. During such time as the pump is in operation and the burner flame persists, the vacuum is maintained in the upper part of the cylinder 77, raising the piston, withdrawing the pin 73 from the lever 65, and permitting the float exclusively to control the oil valve and regulate the replenishment of the oil'supply in the oil reservoir in response to the demands of the pump. If the motor and pump are stopped, through action of the room thermostat, the vacuum no longer being maintained, the piston will drop, cutting oflt' the further supply of oil to the oil chamber. When the motor and pump, however, are again started into operation by the action of the room thermostat, oil is forced from the supply chamber to the burner nozzle and there ignited by the pilot light. The air valve is thereupon promptly closed by the action of the thermostatic diaphragm, and the piston 7 5 raised, permitting the oil valve to open and the oil supply to be replenished under the control of the float. The supply of oil remaining in the oil reservoir after the stoppage of the apparatus in the manner described and in the course of the normal operation of the burner is adequate to start the apparatus into operation and insure the raising of the piston 7 5 before suchsupply can be exhausted, provided that the apparatus is properly functioning.

If, however, from any cause, during the operation of the motor and pump, the burner fiame fails or becomes so reduced as not. to

supply the necessary amount of'heat to move the diaphragm 81 to an air-valve-seating position, or, if when the motor and pump are started into operation by the action of the room thermostat, the fuel fails to be ignited, the pump and motor will continue to run but only on the oil remaining in the oil reservoir. As soon as this is sufficiently exhausted to drop the float, if the burner is not then ignited to generate the required amount of heat, the float causes the opening movement of the switch 101, cutting the motor out of circuit and stopping the further operation of the burner until the defect, whatever it may be, is remedied. The period during which the motor'will thus temporarily operate will depend upon the amount of oil available in the oil reservoir, but this need only be suflicient to overlap by a substantial margin the period normally required to cause the thermostat to act when the burner is normally functioning.

Accordingly, if any defect or trouble arises in the burner, such, for example, as the extinguishment of the pilot light, failure of the oil supply, clogging of the passages, leakage at the ]0lIltS, presence of water or other for- In the normal functioning of the burner,

the apparatus will automatically start and stop under'the action of the room thermostat. In the case of a stoppage due to a trouble or defect, however, it is necessary to refill the oil reservoir and raise the float, since its automatic stoppage under those conditions has exhausted the oil from the float chamber and the motor circuit will remain open until the float'rises. In order a ain to start up the apparatus after it has been stopped due to a trouble or defect, and after the trouble or defect has been remedied, manual or recycling means are provided for lifting the weighted piston so as to reestablish operative conditions in the apparatus. For this purpose a manually-actuated, piston-lifting device is provided (see Fig. 3) in the form of the upright, recycling rod 115 which is slidably mounted in the walls of the cylinder 77. The rod 115 has a reversely turned end 117 which extends under the piston 75 and in the lowered position of the rod is out of com tact therewith. When the piston is down, however, the exteriorly exposed head 119 secured to the rod may be grasped, causing the end 117 to engage and lift the piston to the top of thecylinder, withdrawin the weight of the piston and the pin 73 rom the oil valve. Oil thereupon flows through the valve into the float chamber, the float rises, and, when the level approximates the maximum height, the mercury switch 101 is thrown to the on position. This reestablishes the motor circuit, starting the motor and pump into operation. The recycling rod may then be released, allowing the piston to descend to its normal position, cuttin the oil oil from the tank. As soon as the el ignites at the burner and the thermostat functions, the piston is then lifted by the pump created vacuum and the burner continues to function normally as before.

While I have herein shown and described for the purposes of illustration one specific embodiment of the invention, it is to be understood that extensive deviations may be made from the form and relative arrangement of parts and in the application of the principles herein illustrated, all without departing from the spirit of the invention.

Claims.

1. In a liquid-fuel heating system, the combination with a burner, of a fuel-supply valve, pneumatically controlled means for actuating the valve, a controlling thermostat comprising a bi-metallic diaphragm, a support for the diaphragm having an air supply passage therethrough, said diaphragm being exposed on one side to the heat of the burner and on the opposite side to a current of cooling air passing through said air supply passage, an air valve for controlling said pneumatically controlled, valve actuating means, a lost motion connection between the diaphragm and the valve comprising a rod connected at one end of the diaphragm and frictionally engaged with a sleeve connected to the valve, the diaphragm when heated being adapted to move in a direction to seat the valve and when cooled to be moved in the opposite direction to open the valve, and a limiting device to limit the opening movement of the valve.

2. In a liquid-fuel heating system, the combination with a burner, of means for controlling the liquid fuel supply, pneumatically actuated means for governing said fuel supply control means, an air valve for controlling said pneumatically actuated means and a thermostat device for actuating the valve, the same comprising a bi-metallic thermostatic member exposed to the heat of the burner, a lost motion connection between the thermostatic member and the valve, and a limiting device to limit the opening movement of the valve.

3. In a liquid-fuel heating system, the combination with a burner, of means for controlling the liquid fuel supply, pneumatically actuated means for governing said fuel supply control means, and a thermostatic device for controlling said pneumatically actuated means, the same comprising. a bimetallic, thermostatic diaphragm, and a shell, having an air supply passage therethrough, supporting the diaphragm for exposure on one side to the heat of the burner and on the opposite side to a current of cooling air passing through said air supply passa e.

In a liquid-fuel heating system, the combination with a burner, of means to control the fuel supply, pneumatically actuated means for governing said fuel-sup ly, control means, an air valve for control ing said pneumatically actuated means, and a thermostatic device for actuating the valve, the same comprising a bi-metallic thermostatic member, a shell having an air supply passage therethrough, the thermostatic member being exposed to said air supply passage, a va ve seat in said shell, an air pipe connected to the pneumatically actuated means and communicating with the air supply passage when the valve is opened, and a lost-motion .connection between the valve and the thermostatic member whereby the valve is opened or closed by the movement of said member.

5. In a liquid-fuel heating s stem, the combination with a combustion chamber, of a burner, a fuel supply valve, and means for cutting off the fuel supply on the failure of the burner flame, the same comprising a bimetallic thermostatic diaphragm and a shell supporting the diaphragm and having an air supply passage leading to the combustion chamber through said shell, said diaphragm having one side exposed to the heat of the burner and the opposite side to a current of cooling air through said air supply passage in said shell.

6. In a liquid-fuel heating system, the combintaion with a burner, of means for cutting off the fuel supply on the failure of the burner flame, the same comprising a bi-me tallic thermostatic member, a valve, a lostmotion connection between said member and the valve comprising a rod connected at one end to the member and frictionally engaged with the valve, the thermostatic member being adapted to move in one direction to seat the valve and in the opposite direction to open the valve, and a limiting device to limit the opening movement of the valve.

In testimony whereof, I have signed my name to this specification.

EZEKIEL F. WHITE.

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