US2554491A - Oil burner and fuel cutoff system - Google Patents

Description

May 29, .1951 H. E. EARL OIL BURNER AND FUEL CUTOF'F SYSTEM 2 Sheets-Sheet 1 INVENTOR.

,77'7IFNE' Filed Jan. 17, 1948 May'29, 1951 H. E. EARL OIL BURNER AND FUEL CUTOFF SYSTEM Filed Jan. 17, 1948 ZSheets-Shec 2 iii;

A A Q S X m1 M M FM, m N M 2 d J m 5 Patented May 29, 1951 UNITED STATES PATENT OFFICE OIL BURNER AND FUEL CUTOFF SYSTEM Howard E. Earl, Bloomington, 111., assignor to Eureka Williams Corporation, Bloomington, 111., a corporation of Michigan Application January 17, 1948, Serial No. 2,881

' is formed by mixing together a small quantity of air and fuel at substantially equal low pressures and then igniting and burning this mixture beyond a burner nozzle through which the main air supply for the burner system also is discharged.

Some of the objects of the invention are i provide:

An oil burner system of the low pressure type @in which the oil supply to the mixing nozzle .mains automatically cut off until the mechanics.

elements of the system are operating at a prr determined or normal operating speed and then supplying fuel to the nozzle during the norms. operation of the burner.

An oil burner system in which the oil Suppl to the mixing nozzle of the burner is cut off whey themechanical elements of the burner cease operate under normal operating conditions and. start to slow down at the end of a burner operating cycle.

An oil burner employing a pumping unit 2 one of the mechanical elements thereof and in which pumping unit the oil pumping mechanism is rendered inoperative below a predetermineor normal operating speed for such mechanism.

An oil burner system employing a centrifugally actuated switch, a solenoid actuated valve, and a fuel pumping mechanism, all of which operate in such manner as to cut off the fuel supply to the burner nozzle at the beginning and at the end of an operational cycle when the mechanical elements of the burner system are operating below a predetermined operating speed.

Other and further objects of the invention will be apparent by reference to the accompanying drawings of which there are two sheets, which by way of illustration, show a preferred embodiment and the principles thereof and what I now consider to be the best mode in which I have contemplated applying these principles. Othe embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims. I also contemplate that of the several difierent features of my invention, certain ones thereof may be advantageously employed in some applications separate and apart from the remainder of the features.

Referring particularly to the drawings:

Fig. 1 illustrates an elevational view of an burner system embracing the principles of the: invention.

Figs. 2 and 3 represent a. schematic view of the principal elements of the charge forming and fuel burning elements of the oil burner system illustrated by Fig 1.

Fig. 4 is a fragmentary transverse sectional view through the fuel metering pump embraced in the fuel pumping mechanism illustrated by Fig. 2. Fig. 4 is taken in the plane of line 4-4 on Fig. 2 looking in the direction of the arrows.

Referring particularly to Fig. 1, the numeral Ill indicates generally an oil burner apparatus or system adapted to be supported upon a frame ii. Extending upwardly from the central portion of the frame II is a housing I2 to which is attached on opposite sides of the top thereof a motor l3 and a pumping unit 14. The central portion of the aforesaid upper part of the housing l2 provides a fan housing [5 in which is located a centrifugal fan or blower H. The 1110- tor l3 drives the fan I! through a driving shaft 18 and which shaft in turn drives the shaft id of the pumping unit [4 through a coupling 2|. A transformer 22 for the electrical apparatus of the system is secured to one side of the lower part of the housing l2, while the oil burner control mechanism 23 is secured to the opposite side of the lower portion of the housing l2.

The main air supply for the oil burner system Ill is supplied by the fan I"! through a main air supply conduit 24 which terminates in a sec-- ondary burner nozzle 25 adapted to be disposed in the fire box or combustion chamber of a heating system, not shown, but with which the oil burner apparatus referred to is adapted to be employed. Burner nozzle 26 is provided with spirally disposed internally projecting vanes 27 for rotating or whirling the main air supply received from the conduit 24. Immediately within the end of the burner nozzle 26 is a low pressure air and oil mixing nozzle 28 which is adapted to supply a rich mixture of oil and air to the central portion of the burner nozzle 26 to be ignited and burned with the main air supply received from the conduit 24. The mixing nozzle 28 comprises a discharge orifice 29 communicating with a plurality of mixing passages 3| which in turn communicate with an annular air supply passage 32 formed internally of the mixing nozzle 28. Within the air supply passage 32 is formed a duel supply chamber 33 which com municates with the mixing passages 3| through angularly disposed fuel supply passages 34. EX- tending coaxially with respect to the air supply conduit 24 is a pair of air and fuel delivery conduits 36 and 3'1 respectively within which are provided air and fuel delivering passages 38 and 39, also respectively. The passage 33 communicates with the air supply chamber 32, while the passage 39 communicates with the fuel supply chamber 33.

just back of the mixing nozzle 28 is an ad'ustable bracket ll in which ignitor fo burner apparatus is secured. The ignitor s2 is provided with electrodes id adjacent the discharge orifice 2s and within the burner nozzle 26. The electrodes 44 are adapted to provide an electrical spark at the beginning of each cycle of operations of the oil burner ap; igniting the combustible mixture formed within the burner nozzle 26 by the fuel and air mixture discharged by the orifice 29 and the main air supply delivered to the burner nozzle by the conduit 24. a

The pumping unit It comprises a casing it within which is contained an air supply pur l 46, a fuel supplypump island a fuel meterl pump 48. The pumps 46; 41-, and ii: are all mounted within the casing 16 in such manner as to be driven by the pumping unit shaft I9. The air pump 46 is formed in an air pump housing 49 secured to one side of a central web or support portion SI of the casing it, while the fuel pump 41 and fuel metering pump 48 are disposed with in a housing 52 secured to the opposite side of thesup-port The shaft I9 is mounted within the pump housings t9 and 52 upon self-aligning bearings 53 and 54, and between the bearings there is provided a fluid seal 55 having a movable member 5-? secured to the shaft ii) and a stationary member 58 secured by a diaphragm 59 to one side of the support 5i. The support 5| and the pump housing 52 are provided with a centrally disposed fuel chamber 6! in which the seal 58 and the bearing 54 are located.

The air pump 4% is provided with an inlet port 62 communicating with an inlet passage t3 which supplies air to the pump from the annular space within the casing. I5 surrounding the housings 49 and 52. A discharge port (is is provided in the housing' iii on the discharge side of the pump lii. The discharge port coinmunicates with the discharge passage 8B which communicates with the air delivery passage 38 for supplying air to the nozzle 22% through an air supply conduit '37. The passage 56 is also provided with a by-pass 5'8 controlled by a needle valve I39 which is accessible from the exterior of the casing I6. The opposite end of the -pass 88 is in open communication with the annular space within the casing lithrough a port indicated at In.

The fuel pump 41 has an inlet port 5 I communicating with an inlet passage 72 supplied with fuel from a fuel supply chamber 73 which in turn communicates with the fuel supply tank, not shown, through a conduit The fuel discharge for the pump ll is provided by a discharge port which communicates with the chamber 6 through a discharge passage ii. A by-pass it from the chamber permits fuel to return to the fuel tank through a by-pass valve '59 and a fuel return conduit Si, also conimunicating with the tank not shown.

Instead of eniployingthe conduit 8!, the opening in the casing I6 in which the conduit is threaded may be closed by a plug and in such event the by-pass 18' may communicate with the fuel supply chamber 's'iithrough an opening, not shown, but which may be formed axially with respect to a screw 82 disposed in a threaded opening 83 formed'in t; e casing in such manner as to communicate with the by-pass '58. The chamber Bl also communicates through delivery passages 86 with a pumping chamber 8? formed in the housing 52. The fuel metering pump 48 is located within the pumping chamber 81.

In order to provide a resilient drive means for the fuel metering pump 58, the shaft coupling 2I, the bearings 53 and 5a, and the pumps 46 and ii are all mounted upon the shaft IS in such to permit a movement of the shaft and In order to provide means for resiliently urging the shaft is within the bearings 53 and ii in a direction toward the fuel metering pump there is proviced within the chamber 6! and beyond the diaphragm 55 a spring 88 which is disposed between the pumping housing l9 and the stationary member 53' of the seal 55. The spring 88, being under compression, tends therefore to move the shaft I8 toward the fuel metering pump 48 by reason of the fact that the seal is secured to the shaft IP, by the rotating member 5"! of the seal 56. The end of the shaft IS- terminates at the pumping chamber 8? adjacent the rotor of the metering pump .8 which is adapted to be rotated by the shaft I9 against a wall indicated at GI formed in the housing 52 on one side of the pumping chamber 81. The rotor 89 is rotated by the shaft [9' through the energy imparted by a ball 92 which is partly seated in openings J3 and formed in the shaft I9 and rotor so respectively. The opening 93 is formed the end of the shaft lSeccentrically with respect thereto, while the'opening 94. is formed in the rotor 89 concentrically with respect thereto. It will be apparent that the spring 88 tends to hold the shaft is resiliently against the ball 92 and that the ball 92 tends to hold rotor 89 resiliently against the wall Ill. The rotor 89 has a radially disposed cylindrical opening 96 formed therein in which is reciprocably mounted a piston iii. The opposite end of the piston 9! is resiliently m .mted upon a spring 93 in a spherical bearing member 99 which is mounted for linear and oscillatory movement in a cylindrical opening Ilil formed in the housing 52 in parallel relation to theaxis of the shaft 9. The cylindrical opening Iiil communicates with and provides a continuation of the pumping chamber 8'5.

The wall GI is provided with an annular pressure chamber IE2 which is formed as a groove extending within the wall and against which groove the rotor 89 rotates. The chamber I02 communicatesthrough a passage I03 with a discharge port IEM-which isalso formed in the wall e: and which communicates with the cylinder 96 through a passage I06 when the piston Si! is moving inwardly with respect to the cylinder 96. The passage I66 is formed in the rotor 39 between the cylinder 96 and the Wall 9|. An inlet port it? also is formed in the Wall 9| and within the annular pressure chamber I02 and is adapted to communicate with the passage I96 when the piston 97 is moving outwardly within the cylinder The inlet port I'fi'l' communicates with the pressure chamber 87' t .rough an inlet passage I38 while the-discharge port I04 communicates with the fuel delivery passage fig'through a fuel supply passage Its and a fuel supply conduit I l I. The passages I93 and I09 are respectively con nected to surge chambers I I2 and l l3 which are adap ed to dampen out vibrations in fluid pressure which may-'occurwi'thin the passages.

The fuel supply conduit" I1 I is connected intermediate the ends thereof to a valve casing H4 having an orifice I I6 controlled by a needle valve starting winding I 24 of the motor I3. after the motor will start and will accelerate un- III operated by the armature IIB of a solenoid II9 of a solenoid actuated valve member I2 I.

When the solenoid H2 is electrically energized the armature II8 will be moved in such manner as to open the needle valve II? with respect to the seat II6 to permit the normal flow of fluid through the fuel supply conduit III. When the solenoid I I9 is not energized the needle valve I I! will close by gravity upon its seat II6 thereby preventing the flow of fuel through the fuel supply conduit III. Mounted upon shaft [8 of the motor I3 is a centrifugally actuated switch I22 having a contact member I23 adapted alternate- 1y to close an electrical circuit through the starting winding I24 of the motor I3 and the solenoid I I9 of the solenoid actuated valve I2I. The contact member I23 has a two-way contact I26 adapted alternately to engage contacts I21 and I26 for such respective purposes. The contact member I 23 is mounted at the end thereof opposite the contacts I26 upon a portion of the motor frame I29 through which the shaft I8 pro- 'je'cts. On one side of the contact member I23 is weights I38. The weights I38 are formed in the shape of levers, one of the ends of each lever being adapted to move outwardly by centrifugal force resulting from rotation of the shaft I8 into engagement with the inner surface of the arms The opposite end of each lever is pivotally mounted at I39 in openings formed in the periphcry of the ring I32. It will be apparent that the outward movement of the weights I38 resulting am the rotation of the shaft It will move the ring I32 against the compression of the spring I33, thus permitting the contact member I23 to en age the contact I 26 with the contact I28. The

spring I33 is constructed and arranged in such manner that the contact I26 will so close upon the contact I28 when the motor I3 has reached a pre I determined operating speed which preferably is just below the normal operating speed of the motor [3. Just below such predetermined operating speed it will be apparent that the spring I33 will'move the ring I32 and the contact member I23 in such manner as to open the circuit through contacts I 25 and I28 and to close the circuit between contacts I26 and I21.

- Contact I28 is connected to one side I 4|.of a power line I42 in series with the solenoid H3 of the solenoid actuated valve I2I by conductors in- (heated at I43. Contact I21 also is connected to the same side I4I of the line I42 by conductors I44. Contacts I25 and the running winding I43 of the motor I3 are connected to the other side I41 of the line I42 by conductors I48 and I49 respectively. The running winding I46 also is con nected to the side I4I of the linein parallel with starting winding I24 by one of the conductors I44. When switch I5I controlling the line I42 is closed prior to the starting of the motor I3, it will be apparent that an electrical circuit will be made through contacts I26 and I2! for energizing the Theretil such time as the motor shaft I8 has reached the predetermined speed previously referred to in which event the operation of the centrifugally actuated switch I22 Will close the circuit through the contacts I26 and I28 thereby opening the circuit through the starting winding I24 and closing the circuit through the solenoid II9 of the solenoid actuated valve I2I It will also be apparent that upon closing the switch I5I controlling the line 42, that the starting of the motor I3 will result in driving the air pump 46, the fuel pump 4?, and the fuel metering pump 48 at the speed of the motor shaft. However, due to the fact that the solenoid actuated valve I 2I is not at such time energized in such manner as to open the conduit I I I beyond the needle valve I I6, fluid pressure in the discharge port I84, in the pressure chamber IE2, the discharge passage I232 and the discharge conduit III will tend to increase Icetween the metering pump 48 and the solenoid actuated valve I2I. Since the rotor 89 of the metering pump 48 is exposed to the fluid pressure within the pressure chamber 582 and the discharge passage I54, it will be apparent that the rotor 89 will tend to be forced away from the wall 9! against the compression of the spring 88. Since liquid fuel is relatively non-compressible. it will also be apparent that a considerable increase in fluid pressure in the pressure chamber I92 and the discharge port I64 will occur immediately upon the starting of the motor I3 and the pumps 46, 47, and 48. When the fluid pressure in the pressure chamber lit?! and the discharge port 1534 has increased to a predetermined value, depending upon the calibration of the spring 88, the rotor 89 will be moved away from the wall 9| a suflicient amount to render the metering pump 48 inoperative for the pur pose of pumping measured quantities of fuel from the inlet port I Bl to the discharge port I64. Thereafter the fluid pressure in the pressure chamber I82 and the discharge port will be relieved along the well 9| to the pumping chamber 21 and in such event the fiui-dpressure in the supply conduit ii I willdecrease or in any event will not tend to increase beyond the predetermined fluid pressure previously referred to.

When the motor I3, the pump 46, the pump 4?, and the fuel metering pump 48 have all reached predetermined speed just below normal operating speed for all of such units, the centrifugally actuated switch I 22 will operate in such manner as to open the circuit between the contacts i26 and I2! and to close the circuit through the contacts I26 and I26 thereby actuating the solenoid actuated valve IZI in such manner as to open the needle valve Ill upon the orifice I Hi to permit the flow of fuel through the fuel supply conduit III. When the solenoid actuated valve I2! is so opened, the pressure in the discharge port I @4. and the pressure chamber IE2 will be relieved to such an extent as to permit the rotor 89 to be resiliently urged by the spring 88 into operative relation to the wall i i. Thereafter the metering pump 48 will supply measured quantities of fuel from the pumping chamber 8'! to the nozzle 28 to be there mixed with air at approximately the same pressure delivered by the air pump 46 to the nozzle 28.

Operation of the ignitor 42 thereupon will ignite the combustible charge formed in the burner nozzle 26 and the burner thereafter c i e to operate under normal operatin during the continuation of an operating cycle for the oil burner apparatus. When the switch I! is opened at the end of such normal operating cycle for the oil burner apparatus by operation of the control mechanism 23 the speed of the motor shaft It will decrease. When the speed of shaft [8 is decreased to the predetermined operating speed previously referred to, the centrifugally actuated switch i22 will operate to open the circuit between contact/5126 and I23. However, the circuit through switch lei having already been opened, the solenoid actuated valve l2l will again permit the closing of the needle valve li'l upon the seat H 5 immediately upon opening of the circuit through switch NH. The resulting immediate rise in pressure in the supply conduit ill will increase the fluid pressure in the pressure chamber I62 and the discharge port I84 to such an extent as to render the fuel metering pump 48 inoperative in the manner previously described.

It will be apparent that while air will be sup- 13, the pump 46, the pump 4?, and the fuel metering pump 48.

While I have illustrated and described a preferred embodiment of my invention, it is understood that this is capable of modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall Within the purview of the following claims.

I claim:

1. An oil burner system comprising a burner nozzle, fuel and air pumping means for supplying fuel and air to said burner nozzle, said fuel pumping means having a discharge port connected with said nozzle, means responsive to the speed of operation of said fuel and air pump-ing means for increasing the fluid pressure in said discharge port, said speed responsive means being operative for preventing flow of fuel to said nozzle and for increasing said fluid pressure at speeds below a predetermined operational speed for said fuel and air pumping means, and means responsive to a predetermined increase in said fluid pressure in said discharge port for rendering said fuel pumping means inoperative for supplying said fuel to said burner nozzle below said predetermined operational soeed for said pumping means, said speed responsive means being operative for relieving the fluid pressure in said discharge port and permitting flow of fuel to said nozzle at speeds of said pumping means above said predetermined operational speed thereof, said air pumping means being operative at speeds below and above saidpredeterinined speed for supplying a stream of secondary air past said nozzle and said nozzle being operative for mixing the fuel and air supplied thereto and discharging the resulting mixture into said secondary air stream.

2. An oil burner system comprising a burner nozzle, fuel and air pumping means for supplying fuel and air to said burner nozzle, said fuel pumpin means having a discharge port connccted with said nozzle, means responsive to the speed of operation of said fuel and air pumping means for increasing the fluid pressure in said discharge port, said speed responsive means being operative for preventing flow of fuel to said nozzle and for increasing said fluid pressure at speeds below a predetermined opera tional speed for said fuel and air pumping means, means responsive to a predetermined increase in said fluid pressure in said discharge port for rendering said fuel pumping means inoperative for supplying said fuel to said burner nozzle below said predetermined speed for said pumping means, and said fuel pumping means having a pressure chamber connected to said discharge port and exposed to said pressure responsive means for increasing the total effective pressure of said fluid upon said pressure responsive means, said speed responsive means being operative for relieving the fluid pressure in said discharge port and pressure chamber and ermitting flow of fuel to said nozzle at speeds of said pumping means above said predetermined operational speed thereof, said air pumping means being operative at speeds belowand above said predetermined speed for supplying a stream of secondary air past said nozzle and said nozzle being operative for mixing the fuel and air supplied thereto and discharging the resulting mixture into said secondary air stream.

3. An oil burner system comprising a burner nozzle, fuel and air pumping means for supplying fuel and air to said burner nozzle, said fuel pumping means having a discharge port con-- nected with said nozzle, means responsive to the speed of operation of said fuel and air pumping means for increasing the fluid pressure in said discharge port, said speed responsive means being operative for preventing flow of fuel to said nozzle and for increasing said fluid pressure at speeds below a predetermined operational speed for said fuel pumping means, means responsive to a predetermined increase in said fluid pressure in said discharge port for rendering said fuel pumping means inoperative for supplying said fuel to said burner nozzle below said predetermined speed for said pumping means, and said fuel pumping means having an annular pressure chamber surrounding said discharge port and exposed to said pressure responsive means for increasing the total eifective pressure of said fluid upon said pressure responsive means, said speed responsive means being operative for relieving the fluid pressure in said discharge port and pres-, sure chamber and permitting flow of fuel to said nozzle at speeds of said pumping means above said predetermined operational speed thereof, said air pumping means being operative at speeds below and above said predetermined speed for supplying a stream of secondary air past said nozzle and said nozzle being operative for mixing the fuel and air supplied thereto and discharging the resulting mixture into said secondary air stream.

4. An oil burner system comprising a burner nozzle, fuel and air pumping means for supplying fuel and air to said burner nozzle, said fuel pumping means having inlet and discharge ports connected with said nozzle, means responsive to the speed of operation of said fuel and air pumping means for increasing the fluid pressure in said discharge port, said speed responsive means being operative for preventing flow of fuel to said nozzle and for increasing said fluid pressure at speeds below a predetermined operational speed for said fuel pumping means, means responsive to a predetermined increase in said fluid pressure in said discharge port for rendering said fuel pumping means inoperative for supplying said fuel to said burner nozzle below said predetermined speed for said pumping. means, and said fuel pumping means having an annular pressure chamber surrounding said inlet and discharge ports and exposed to said pressure responsive means for increasing the total effective pressure of said fluid upon said pressure responsive means, said speed responsive means being operative for relieving thefluid pressure in said discharge port and pressure chamber and permitting flow of fuel to said nozzle at speeds of said pumping means above said predetermined operational speed thereof, said air pumping means being operative at speeds below and above said predetermined speed for sup-plying a stream of secondary air past said nozzle and said nozzle being operative for mixing the fuel and air supplied thereto and discharging the resulting mixture into said secondary air stream.

5. An oil burner system comprising a burner nozzle, fuel pumping means for supplying said fuel to said burner nozzle, said fuel pumping means having an inlet port and a discharge port connected with said nozzle, means responsive to the speed of operation of said fuel pumping means for increasing the fluid pressure in said discharge port, said speed responsive means being operative for preventing flow of fuel to said nozzle and for increasing said fluid pressure at speeds below a predetermined, operational speed for said fuel pumping means, means responsive to a predetermined increase in said fluid pressure in said discharge port for rendering said fuel pumping means inoperative for supplying said fuel to said burner nozzle below said predetermined speed of said pumping means, and said fuel pumping means having an annular pressure chamber surrounding said inlet and discharge ports and exposed to said pressure responsive means for increasing the total effective pressure of said fluid upon said pressure responsive means, said speed responsive means being operative for relieving. the fluid pressure in said discharge port and permitting flow of fuel to said nozzle at speeds of said pumping means above said predetermined operational speed thereof.

6, An oil burner system comprising a burner nozzle, fuel pumping means for supplying said fuel to said burner nozzle, said fuel pumping means having a discharge port connected with said nozzle, means responsive to the speed of operation of said fuel pumping means for increasing the fluid pressure in said discharge port, said speed responsive means being operative for preventing flow of fuel to said nozzle and for increasing said fluid pressure at speeds below a predetermined operational speed for said fuel pumping means, means responsive to a predetermined increase in said fluid pressure in said discharge port for rendering said fuel pumping means inoperative for supplying said fuel to said burner nozzle below said predetermined speed of said pumping means, and said fuel pumping means having a pressure chamber surrounding said discharge port and exposed to said pressure responsive means for increasing the total effective pressure of said fluid upon said pressure responsive means, said speed responsive means being operative for relieving the fluid pressure in said discharge port and permitting flow of fuel to said nozzle at speeds of said pumping means above said predetermined operational speed thereof.

'7. An oil burner system comprising a burner nozzle operative for discharging a combustible mixture of fuel and air, a pumping unit associated with said burner nozzle and operative for supplying said mixture to said burner nozzle and a secondary air stream past said nozzle into which said mixture is discharged, said pumping unit comprising a pumping chamber having a rotor disposed therein, resilient means for rotating said rotor against a wall of said chamber for pumping the fuel mployed in said m xture to said burner nozzle, said Wall having a discharge port therein in opposite relation to said rotor, the fluid pressure in said discharge port being opposed to said resilient means, and means responsive to the speed of said resilient means for discontinuing the supply of said fuel to said burner nozzle and for increasing said fluid pressure in said discharge port, said rotor being movable by the fluid pressure in the discharge port said resilient means away from said Wall for relieving said fluid pressure intosaid pumping chamber below a predetermined speed of operation of said resilient means.

8. An oil burner system comprising a burner nozzle operative for discharging a combustible mixture of fuel and air, a pumping unit associated with said burner nozzle and operative for supplying said mixture to said burner nozzle and a secondary air stream past said nozzle into which said mixture is discharged, said pumping unit comprising a pumping chamber having a rotor disposed therein, resilient means for rotating said rotor against a wall of said chamber for pumping the fuel employed in said mixture to said burner nozzle, said wall having inlet and discharge ports therein in opposite relation to said rotor, means forming an annular pressure chamber surrounding said inlet and said discharge ports, said pressure chamber being in open communication with said discharge port and being formed between rotor and said wall, the fluid pressure in said discharge port and pressure chambers being opposed to said resilient means, and means responsive to the speed of said resilient means for discontinuing the supply of said fuel to said burner nozzle and for increasing said fluid pressure in said discharge port and said pressure chamber, said rotor being movable by the fluid pressure in the discharge port and pressure chamber against said resilient means away from said wall for relieving said fluid pressure into said pumping chamber below a predetermined speed of operation of said resilient means.

9. An oil burner system comprising a burner nozzle, means for supplying a combustibl mixture of fuel and air to said burner nozzle, said fuel supplying means comprising a fuel metering pump having a discharge port, means supporting said pump for movement in response to pressure, said fuel metering pump being movable in response to the pressure of fuel in said discharge port for rendering said pump inoperative to sup ply fuel to said nozzle, means responsive to the operation of said fuel and air supplying means for increasing the pressure of fuel in said discharge port below a predetermined operating speed for said fuel and air supplying means, and means forming a pressure chamber connected to said discharge port and associated with said fuel metering pump for accelerating the movement of said fuel metering pump in response to said fuel pressure.

10. An oil burner system comprising a burner nozzle, means for supplying a combustible mix ture of fuel and air to said burner nozzle, said fuel supplying means comprising a fuel metering pump, means supporting said pump for movement in response to pressure, said fuel metering pump being movable in response to the pressure of fuel in the discharge side of said pump for rendering said pump inoperative to supply fuel to said nozzle below a predetermined operating speed for said supplying means, and means responsive to the operation of said fuel and air supplying means for increasing said discharge pressure for rendering said pump inoperative below said predetermined operating speed for said fuel and air supplying means.

11. An oil burner system comprising a motor, fuel and air supplying means driven by said motor, a mixing nozzle, conduits connecting said mixing nozzle to said fuel and air supplying means, a centrifugally actuated switch associated with said motor, a solenoid operated valve in said fuel conduit, said switch and said solenoid actu ated valve being provided with an electrical circuit for operating said valve to open the same when the circuit through said switch is closed, said centriiugally actuated switch being operative for closing said circuit for actuating said solenoid actuated valve when said motor is operating at a predetermined speed, said solenoid actuated valve being operative to open said fuel supply conduit when said circuit is closed, said air "supplying means being operative at speeds below and above said predetermined speed for supplying a stream of secondary air past said nozzle and said nozzle being operative for mixing the fuel and air supplied thereto and discharging the resulting mixture into said secondary air stream.

12. An oil burner system comprising a motor, fuel and air pumping means driven by said mo, tor, a mixing nozzle for said oil burner system, said mixing nozzle being connected to said fuel and air pumping means by fuel and air con-- duits, a centrifugally actuated switch associated with said motor, a solenoid valve closing said fuel conduit, an electric circuit for said motor, said switch and solenoid actuated valve being connected in said electrical circuit in parallel relation to said motor for operating said valve to open the same when the circuit through said switch is closed, said centrifugally actuated switch being operative for closing said circuit above a predetermined speed of operation of said motor, said solenoid actuated valve being operative for closing said fuel supply conduit when said circuit is opened, and means responsive to the closing or said fuel supply conduit for rendering said fuel pumping means inoperative, said air pumping means being operative at speeds below and above said predetermined speed for supplying a stream of secondary air past said nozzle and said nozzle being operative for mixing the fuel and air supplied thereto and discharging the resulting mixture into said secondary air stream.

13. An oil burner system comprising an oil and air mixing nozzle, an air pump connected with said nozzle for supplying air thereto, an oil pump, means forming a communication between said oil pump and said nozzle for supplying oil thereto, a motor for operating said pumps, a shut-off valve in said communication which prevents flow of oil to said nozzle when the valve is closed, means effective when the motor attains a pre determined speed for opening said valve, means driven with said air and oil pumps and effective above and below said predetermined speed for flowing a stream of secondary air past said nozzle, said nozzle being constructed and arranged to mix the oil and air supplied thereto and to dis- 1?. charge such mixture into said secondary air stream, and means for dissipating the pressure in said communication ahead of said valve when said valve is closed and said motor is operating below said predetermined speed.

14. An oil burner system according to claim 13 wherein said pressure dissipating means comprises a by-pass around said oil pump.

15. An oil burner system according to claim 13 wherein said oil pump comprises two parts biased together which form said pressure dissipating means, said parts being separable in response to fluid pressure in said communication to relieve aid pressure when said valve-is closed.

16. An oil burner system comprising an 1 and air mixing nozzle, an air pump connected with said nozzle for supplying airtheret an oil pump, means forming a communication be tween said oil pump and said nozzle for supplying oil thereto, a motor for operating said pumps. a shut-off valve in said communication biased to closed position and which prevents flow oi oil to said nozzle when closed, means effective when the motor attains a predetermined speed for opening said valve and which permits said valve to close when the motor decelerates below its normal running speed, means driven with said air and oil pumps and efifective above and beiow said predetermined speed for flowing a stream of sec ondary air past said nozzle, said nozzle being con structed and arranged to mix the oil and air supe plied thereto and to discharge such mixture into said secondary air stream, and means for dissi pating the pressure in said communication ahead of said valve when said valve is closed, said shutoff valve being constructed and arranged so that the fluid pressure in said communication does not retard the closing movement thereof.

17 An oil burner system comprising an oil and air mixing nozzle, an air pump connected with said nozzle for supplying air thereto, an .oil pump, means forming a communication between said oil pump and said nozzle for supplying oil thereto, an electric motor for operating said pumps, an electric circuit for said motor, a shut-off valve in said communication which prevents flow of oil to said nozzle when the valveis closed, means energized by said motor circuit when the motor attains a predetermined speed for opening said valve and which permits said valve to close when the motor circuit is opened, means driven with said air and oil pumps and effective above and below said predetermined speed for flowing a stream of secondary air past said nozzle, said nozzle being constructed and arranged tomiX the oil and air supplied thereto and to discharge such mixture into said secondary air Stream/and means for dissipating the pressure said communication ahead of said valve when said valve is closed.

' HOWARD E. EARL.

REFERENCES CITED The iollowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1.482759 Meyers Feb. 5, 1924 1,537,262 Ray May 12, 1925 1,986,003 Lum Jan. 1, 1935 2,028,807 Reiboldt Jan. 28, 1935 2,210,853 Falkenberg Aug. 5, 1940 2,469,271 Logan May 3, 1949

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