US2413655A - Fuel supply controlling means for burners - Google Patents

Description

Dec. 3l, 1946. P'. s. Russel.' 2,413,655

FUEL SUPPLY COTROLLING MEANS FOR BURNERS Filed June 2, 1944 nvvNToR.

Patented Dec. 31, 19h46 UNITED STATES PATENT trici-z Philip S. Russel, Detroit, Mich., assigner to Detroit Lubricator Company, Detroit, Mich., a,

corporation of Michigan Application June 2, 1944, Serial No. 538,394

8 Claims. (Cl. 137-139) The invention relates to new and useful imf provements in a controlling apparatus for liquid fuel burners and has particular rela'tion to valve means for governing the fuel flow to the burner. In the type of oil burner system where the oil fuel is delivered to a spray nozzle, the fuel isl generally supplied by a positive displacement pump delivering fixed quantities of fuel. A valve means is` ordinarily employed to limit the maximum vfuel pressure on the nozzle by by-passing all fuel delivered by the pump in4 excess of that quantity required to maintain a desired nozzle pressure. The fuel which is by-passed by the valve means is delivered either to the inlet side of the pump or back to the supply source.

In the operation of the usual system of this A general character, the motor driven fan supplying air for combustion is mounted on the samshaft as the fuel delivery pump. Depending upon the rate of acceleration of motor speed in starting, there gis a time delay'after closure of the motor switchbefore the motor obtains its rated speed. Also, depending upon the rate of deceleration, there is a time delay between breaking of the energizing moto-r circuit and the time when the motor rotor comes to rest or stop's. L

In view of the fact that safety has demanded pump delivery in 'excess of burner requirements (often in excess of ten times), there is delivered to the burner, full fuel delivery with pump rotation of several hundred R. P. M. which occurs shortly after the motor starts andwell before the'motor reaches its rated speed or R. P. M. On

-the other hand, air for combustion does not reach its required delivery for proper combustion until the motor has reached its rated R. P. M.

Following a period of burner operation, terminated by breaking of the motor circuit, the motor speed decelerates and with deceleration, there immediately starts a` reduction in airfdelivery by the fan. Fuel delivery, however, remains relatively at a constant until such time as the R. P. M. of the motor has reduced to that at which the displacement rate is less than that which will pass through the spray nozzle at the established maximum pressurel regulated by the previously referred to by-pass valve. During this same period between start of deceleration and that R. P. M. at which fuel delivery is reduced, there is a. continued and rapid decrease in amount ofv air delivered to the burner. This results in a period at the expiration of any burner heating or operating cycle in which air for combustion is not delivered in sufcient quantity, resulting in incomplete combustion with attendant carbon monoxide and free carbon.

Putting the above into actual quantities which might beexistent, a fuel pump operating at 1800 R. P. M. has, say, a positive displacement at its v rated R. P. M. of 18 gallons per hour (g. p. h.).

.mentioned undesirable relationships of oil and This is the equivalent of a delivery rate of one g. p. h. per R. P. M. If the nozzle is rated at two g. D. h. at 100# pressure and all fuel delivered in excess of that which will pass through the nozzle at 100# -pressure is by-passed, then the motor R. P. M. can decrease from-1800 to 200 rR. P. M. withv noreduction in delivery through the nozzle.' The'only difference being gradual reduction in quantity of fuel by-passed until at 200 R. P. M., 100# pressure is stillmaintained and no fuel is by-passed. During this period of deceleration from 1800 to 200 R.- P. M., the air delivery is materially reduced with the result of incomplete combustion as above noted.

The present invention provides a control means by which irrespective of the quantity of fuel dellvered by the pump or by the pressure resulting from such delivery, the instant that deceleration starts by breaking of the motor energizing circuit, all fuel ow to lthe nozzle is discontinued. Andin lieu of insufficient air, there results the advantageous effect of continuance of air delivery following discontinuance of fuel delivery. During the period of initiation of operation, there is established in the present invention, a time delay in the delivery of fuel from the pump to the fuel burner nozzle, thereby providing a time period during which the air supply is increased.

It will be understood from the above that one object of the invention, therefore, is to provide an improved means for controlling the flowof oil from the pump to the nozzle so that the above air delivery may be obviated.

Another object of the invention is to provide an improved oil control for the purpose mentioned wherein the oil flow is immediately cut off as soon as the pump motor energizing circuit is Ibroken so as to prevent a continuance of fuel flow during a. period of reduced air delivery.

Another object of the invention is to provide a device for obtaining these results automatically and through means controlled by the oil pressure.

Other objects of the invention will become apparent from the following specifi-cation, from the drawings forming a part thereof, and from the claims hereinafter set forth.

For a better understanding of the invention reference may be had to the accompanying drawing wherein: a

'The single figure illustrates one form of the invention in cr'oss section with certain parts shown diagrammatically so as to illustrate the manner in which the burner operates.

Referring to the figure. an ordinary gun type nected to a pump I3 and normally the. pump and a blower within the casing II will be connected Wires I4 and I5 leading to the l'motor I2 may be connected to-lead-in lines I3 .and -I1 by 'a double pole switch I8, although norinally suitable thermostatically controlled means will be used to make and break the l motor circuit depending upon the temperature vof the space heated by the furnace.

The inlet side of the pump I3 is 'connected by means of a conduit to an oil tank 2|. while the discharge side of the pump is connected by a. conduit 22 to a casing 23. Oil from the casing ilowsthrough a valve opening 24 and into a conduit 25 extending through thel barrel I0 and which has a nozzle 21 at the end of the barrel. Any suitable ignition may be employed for igniting the oil sprayed from the nozzle 21, such as the usual electrical' igniting device `or a suitable form of pilot device. l

, According to the present invention, a valve stem in the casing 23 has a conical end or head 3| engageable with a seat provided by the en d of the outlet conduit formingthe valve opening 24 so as to 'close the opening. .The stem, at its other end, projects into a centrally disposed tubular supporting member '33 having a bottom tothe vmotor shaft so as to 'be driven thereby.

pulled downwardlyfprovided it is out of engagement'with the wall 34.

Below the wall 34., the supporting member 33 has a shorter'tubulary portion 54 which houses one end of a second, helical spr-ing 55 engaging at one end the lower side of the wall 34 and its other an adjustable access plug' 56 threaded into v the'cover 5I., The spring 55 is sufficiently strongl to hold the parts" in the position shown until a predetermined pressure acts against the diaphragm and in thisconnection it may be stated that the spring 33 is relatively weak so as not a spring 62. The by-pass valve 5| acts to main tain or limit the maximum pressure in the casing to a predetermined pressure which, for lnstance, may be one hundredV pounds per'square will be allowed to escape to a wall or partition 34. The stem 30 has its lower portion forming an armature and is slidably guided in the member 33. The stem is resiliently urged toward valve closing position by a coil spring 36 disposed in an upward extending axial bore or opening 31 in the stem. 'I'hls spring. at its upper end, as shown) abuts the bottom or end wallof the opening 31 and at its lower end abutsV inch, and when the pressure exceeds this amount the valve will automatically open and some oil line 83 which leads back to the supply tank 2l or may lead to the `inlet conduit 20. vAny suitable by-pass valve may A be used which allows' oil to fiow back to the tank or inlet side of'the pump when a predetermined pressure is reached. "When the pressure drops I below this predetermined pressure, the by-pass the wall 34, being held under compression therebetween.

The supporting ,fmember`33, at its upper end, projects through Iand is firmly connected and sealed to the central phragm or pressure responsive member 4 0 while the outer'perlpheral portion of the diaphragm is tightly held and sealed against an annular shoulder 4I in the casing by a ring 42 threaded into the casing as indicated at 43. `The diaphragm may be constructed of any suitable and exible material and in the event rubber is employed, the material will be oil resistant. From this now, it should be evident that the upper part of the casing into which the conduit 22 discharges and which forms a pressure chamber, is sealed from that part below the diaphragm and that 'the valve stem is normally urged by the spring into valve closing position so as to preventthe oil from owing from the casing 23 to the nozzle 21.

Below the diaphragm, a solenoid coil-'450i an electromagnetic means surrounds and is mounted rigidly on and for movement with the supporting member 33. Wires 41 and 48 leading to the wires portion of an annular diavalve 6I closes.

If it be assumed now that the switch I8 is closed, the motor- I2 and pump I3 will start operating and oil will be pumped from the tank 2|A into the4 casing 23' As the pressure increases in the casing 23, the diaphragm 40 is flexed downwardly inside its outer margin and as lt moves downwardly, the contact 52 approaches the upper end of the stud 50. The distancebetween the contacts may be varied by adjusting the stud 58 so that more or less movement will berequired before engagement of the contacts occurs and hence engagement of the contacts may be caused to occur at different pressures acting on'the dia- 4 phragm. The pressure at which the contacts 53,

I5 and I4 respectively and thereby connected to the switch I8 are connected respectively to one end of the solenoid coil and to a threaded stud 50 adjustably screw-threaded through and insulated from a removable cover 5I on the lower endof the casing 23. A contact 52 adjacent the upper end of the stud 5I!y is electrically connected to the other end of the solenoid coil 45 which is opposite the end connected to the wire 41. The

contact-52 is engageable with the contact vformed by the upper inner end of the stud 58 so that when contact 52 engages the stud the-solenoid is energized, providing the switch I8 is closed, thereby causing the metal valve stem 30 to be 52 are closed may also be regulated by adjusting the plug 56 which determines the force of the spring 55. When the pressure on the diaphragm reaches a predetermined amount the contacts 50 and 52 engage each other and then the solenoid 45 becomes energized.

vIn the meantime, while the supporting member 33 is moving downwardly away from the end of the valve stem, the spring 36 holds the valve closed. However, as soon as the solenoid is en ergized the stem 3l) is moved through magnetic attraction downwardly into the member 33 until its end again engages the wall 34. This action occurs'quickly, as will be readily understood and the end 3l of the stem quickly opens the valve opening 24 so that oil flows from'the casing to the nozzle 21. The pressure at which the valve opens may be substantially that `established by the by-pass relief valve 5I, butl must, of course, be something less.

Pressure is maintained inthe casing 23 by the pump delivery being in excess of nozzle capacity, requiring normally a continuous by-pass opening ysuillcient for flowof all excess fuel delivered by the pump to the valve'chamber. `The resistancev of the by-pass spring 62 requires a pressure to open the by-pass which is slightly in excess ot vthat required to make circuit at contacts 5B. 52 y so that the metal valve 30 remains open. It might t operation of the switch i8 or thermostat control governed by the temperature of the space heated, the motor and pump stop operating and at the same time the circuit through the solenoid is broken. As soon as the solenoid is thus deenergized, the spring 36 immediately acts to close the valve 30 so that the flow of oil to the nozzle is sharply cut off. This closing of the valve by opening of switch i8 occurs while the oil in the casing 23 is still under desirably high operating pressures .and as a result there is no progressively decreasing flow of oil at the nozzle. In other words, when the valve closes, the full oil spray at the nozzle is quickly and completely stopped and therefore there is no continuance of a progressively decreasing amount of oil under progressively decreasing pressures.

This eliminates the continuance of fuel delivery during a period of reduction in quantity of air delivered.

Generally, it may be observed that nozzle delivery is dependent on two conditions in lieu of the customary one condition. 'Ihere must be established both fuel pressure and the Lenergizing circuit to the pump operating motor. Discontinuanceof either results in immediately stopping all further 4nozzle delivery.

Although only one form of the invention has been illustrated anddescribed in detail, it will be apparent to those skilled in the art that various modiilcations `may be made without departing from the scope of the appended claims.

What is' claimed and is desired to be secured by Letters Patent of the United States is:

1. A valve for controlling the flow of fluid under pressure comprising a casing having an inlet and an outlet, a valve member cooperable with and normally closing said outlet and having an armature, means urging said valve member toward closed position,y electro-magnetic means cooperable with said armature and operable when energized to overcome said urging means and move said valve member to open position, a circuit for said electro-magnetic means, a pressure operated switch in said circuit, means responsive to fluid pressure in said casing and operable to close said switch at a predetermined pressure in said casing', and means supporting said electro-magnetic means on said responsive means.

2. A shut-oir valve for the fuel supplied to an oil burner, comprising a conduit for fuel ilow, means responsive to fuel pressure in said conduit, a switch controlled by -said means, electro-magnetic means carried by said pressure responsive means and having a circuit controlled by said switch, and a valve controlling the ow of fuel under pressure through said conduit and held in open position by said electro-magnetic means when energized.

'3. A control valve device comprising a casing, a diaphragm across the casing, an inlet and outlet in the casing at one side of the diaphragm, a valve carried by and movable relative to said diaphragm and operable to close the outlet, spring means normally urging the valve to a closed position independently of the diaphragm, a solenoid carried by said diaphragm for opening the valve against the action of the spring means, and means for causing the solenoid to be energized when the diaphragm has moved a predetermined amount. 4. A control valve device comprising a casing, a

diaphragm across the casing, an inlet and outlet in the casing at one side of the diaphragm, a

tubular element extending centrally through the diaphragm and to the other side thereof and having its end 'at such other side closed, a valve disposed in and being reciprocatory in said element for closing the outlet opening, spring means in the tubular element for urging the valve to 'closed position, a solenoid coil around the element at said other side of the diaphragm, and meanslfor closinga circuit through the solenoid when the diaphragm is moved a predetermined amount by pressure so as to effect opening move ment of the valve through magnetic; forces.

5. A control valve device comprising ,a casing, a movable diaphragm dividing said casing into a pressure chamber and a coil chamber, said pressure chamber having inlet and outlet ports, a

valve member cooperable with one of said ports' and, having an armature adjacent said diaphragm, an electro-magnetic coil in said coil chamber and cooperable with said armature to actuate said valve member, and a switch in said coil chamber and operable by said diaphragm and controlling current new through said coil.

6. A control valve device comprising a casing having a pressure chamber with inlet and outlet ports, a valve member cooperable with and controlling now through one of said ports and havber, an electro-magnetic coil carried by said responsive member and cooperable with said armature, and means operable by movement of saidI responsive member and controlling current ilow through said coil. g

7. A control valve device comprising a casing having a' pressure chamber with an inlet and an outlet, a valve member in said chamber and normally biased to outlet closing position, a pressure Vresponsive movable member closing a side wall opening of said chamber, cooperable electromagnetic members for opening said valve member and including a coil carried by said responsive member and an armature carried by said valve member, a circuit for said coil, and a switch operable by said responsive member and controlling said circuit to energize said coil and open said valve member.

8. A control valve device comprising a casing having a pressure chamber with an inlet and an outlet, a valve member in said chamber and controlling said outlet, a-pressure responsive movable member closing a side wall opening of said chamber, cooperable electro-magnetic members for opening said valve member and including a coil carried by said responsive member and an armature carried by said valve member, a circuit for said coil, a spring compressed between said valve member and said responsive member and holding said valve member closed upon movement of said responsive member away from said valve member by pressure increase in said chamber, and a switch operable by said responsive member upon increase or pressure in said chamber and controlling said circuit to energize said coil and open said valve member.

- PH S. RUSSEL.

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