US2397986A - Liquid fuel burner system - Google Patents

Description

April 9, 1946. E. J. sENNlNGER LIQUID FUEL BURNER SYSTEM Filed Jan. 27, 1942 5 Sheets-Sheet 1 AUN/L 1 v NE* SO A A INVENTOR. faz/ se April 9, 1945- E. J. SENNINGER LIQUID FUEL BURNER SYSTEM Filed Jan. 27, 1942 5 Sheets-Sheet 2 April 9, 1946- l E. J. SENNINGER 2,397,986

LIQUID FUEL BURNER SYSTEMv Filed Jan. 27, 1942 5 Sheets-Sheet 3 IN VENTOR.

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April 9, 1946. E. J. SENNINGER LIQUID FUEL BURNER SYSTEM 5 Sheets-Sheet 4 Filed Jan. 27, 1942 @E N D m Qq Q o INVENTOR.

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APll 9, 1946. E. J. sENNlNGER LIQUID FUEL BURNER SYSTEM Filed Jan. 2'7, 1942 5 Sheets-Sheet 5 INV ENT OR.

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Patented Apr. 9, 1946 UNITED STATE ascisse LIQUID FUEL BURNER sYs'rEM Earl Joseph Senninger, Chicago, lll., assignor to Sanmyer Corporation, a corporation of Illinoia Application January 27, 1942, Serial No. 428,390

16 Claims.' (Cl. 158-363) This invention relates to liquid fuel burner systems and has for its principal objects to prevent oil from reaching the burner in starting until suflicientair is available, to cut ofi the delivery of oil when the supply of air is impaired or stopped, to prevent the air pump from being run without proper lubrication and to filter or clean the primary or atomizing air supply.

Generally speaking, this' is accomplished by subjecting the oil delivery to the control of a normally closed valve that is opened automatically when the supply of primary or atomizing air reaches a selected pressure and is automati- V cally closed when the pressure drops materially,

by making the presence of considerable lubricating oil necessary to sealing the air pump sutilcient to build up the selected pressure of'primary or atomizing air, by making pressure of primary or atomizing air provide a continual flow of lubricating oil to the air pump and by making the air pump deliver through a combined filter or cleaner and oil separator.

Preferably also there are means to adjust the primary or atomizing air initially and means to increase the oil and secondary air after the burner has started and thereafter to modulate the oil and secondary air as the demand for heat varies.

Further objects and advantages of the invention will appear as the disclosure proceeds and the description is read in connection with the accompanying drawings in which Fig, 1 is a diagram of the system with the parts displaced in such a way as to reveal an organic whole in one drawing;

Fig. 2 is a side elevation of a commercial burner unit embodying the invention with a portion of the modulating motor broken away;

Fig. 3 is a Vertical section taken 3--3 of Fig. 2;

Fig. 3a is a perspective view of a disk forming part of the means for adjusting the capacity of the oil pump; v

Fig. 3b is a perspective View of a crank coopyerating with the disk shown in Fig. 3a;

' Fig. 3c is a perspective View of the end portion of the oil pump casing;

Fig. 4 is a Vertical section through the commercial oil burner unit shown in Fig. 2, taken approximately along the axis of the draft tube;

Fig. 5 is an enlarged longitudinal section of the burner nozzle and associated parts;

Fig. 6 is a transverse section on the line 6--6 of Fig. 5;

Fig. '7 is an enlarged longitudinal section taken lon the line 1'-1 of Fig. 2, and

Figs. 8, 9, 10, l1, 12, are sectional views taken on the line on the lines 8--8, 9-9, lil-I0, II-II, I2-I2,

sponding description are used for the purpose of disclosure only and are not intended to impose unnecessary limitations on the claims, or confine the'patented invention to a particular use.

General description In the diagram (Fig. l) l a main housing I0 provides a tank or reservoir II, for lubricating oil, a chamber I2 for primary or atomizing air above the oil tank, two air filters or cleaners and oil separators I3 and I4, and a secondary fan or blower casing I5, communicating with a lhorizontally directed draft tube I6, passing out through the chamber I2 and within which are the following parts, which have been shown displaced.

The primary air line I1, supplying the nozzle I8, the oil line I9 with its associated heater 20,

also delivering oil to the nozzle I8, and the electrodes 2| associated with the nozzle for igniting the mixture ofoil and air when the burner is started.

The main housing also forms a support for an electric motor 22 which drives the secondary air fan or blower 23, a primary or atomizing air pump 24 and an oil pump 25, here shown as arranged in alignment crosswise to the main housing.

The secondary air fan or blower 23 takes air through the slotted side wall 26 of the fan casing I5 under control of the rotary shutter 21 and delivers it through the draft tube I6 around the mixture of oil and air discharged from the orice 28 of the nozzle I8. The volume is varied by adjusting the rotary shutter 21.

The primary or atomizing air pump 24 takes air in at 29 and delivers it through a pipe 30 into the upper portion of the main housing through the filter I3, which is charged with bronze wool, into the chamber I2 through which it passes over the supply of lubricating oil 3| and up through the lter I4 out through the pipe 32 leading to the air line I1. In fact, that air line, the pipes 30 and 32 and the chamber I2, may be considered as forming a single air line with a storage or pressure chamber in an intermediate position Which insures an even iiow to the nozzle and forms pressure for several other purposes.

The lubricating oil tank II is connected near the bottom by a pipe 33 with the pump 24 and by reason of the air pressure within the chamber I2 oil from the supply 3| in the tank II is continuously delivered to the air pump. As a result, this pump delivers a mixture of air and oil or air and oil foam to the pipe 30 whereby the bronze wool in the filter I3 is made to serve as anyoil separator and an air cleaner and the lubricating oil collected there dropsdown over the outside of the draft tube I6 and returns to the tank II.

The lter I3 is separated from the illter I4 by a partition 34, and the air compressed in the chamber I2 passes up through a second mass of bronze wool in the lter I4 before entering the pipe 32.

In practice, the apparatus is so designed that a pressure from live pounds to twelve pounds, for example, may be built up and maintained in the chamber I2. The pressure in the primary# or atomizing air system is regulated by a bypass 35 connected across the inlet and outlet of pump 24 and controlled by an adjustable valve 36. In this diagram the bypass is shown as external piping, but in practice is worked out through the body or casing of the pump.

The oil pump 25 is preferably built for metering purposes only and should not be used to draw oil from the storage tank. Where gravity feed cannot be used, auxiliary pumping equipment 31 should be provided. 'The oil pump 25 takes oil from the supply line at 38 and delivers it to a -pipe 39 leading to a cylinder 40 of a piston valve which connects it with the pipe 4I, leading to the pipe I9, which delivers to the nozzle I8. I'he cylinder 40 is also connected by a bypass 42 with the supply line 38. The piston 43 movable in the cylinder 40 serves to connect the line 39 with the line 4 I or with the bypass 42, as occasion may require. The piston is associated with an air motor, here shown as a Sylphon bellows 44 located in the primary air chamber I2 and subject to the pressure in the chamber. As a result of this arrangement, oil from the pump 25 is bypassed back to the intake or low pressure side of the pump, either directly or indirectly, until there is sumcient pressure in the air chamber I2 to insure delivery of a proper amount of primary or atomizing air to the nozzle I8, when the pressure in the chamber I2 will overcome the Sylphon 44 and shift the piston valve to a position in which it connects the pipe 39 with the pipe 4I and that, with the pipe I9, becomes one oil supply line from the pump to the nozzle. When, for any reason, the air pressure in the chamber I2 drops below that for which the device is designed and adjusted, the piston valve will shift to the right, cut off the supply of oil to the burner and connect the pump 25 with the bypass 42.

By making the presence of a considerable amount of lubricating oil in the primary air pump 24 necessary to seal it and give it the required capacity, it becomes impossible to run the pump long with insufficient lubrication for, as soon as the' pressure in the chamber I2 drops below that required, the supply of oil is cut oi and the control of any one of the customary forms will put the apparatus on safety and shut the burner down entirely. The presence of the lubricating oil in the air pump 24 in such quantity as to form a foam makes it possible to provide a very efllcient filter with the bronze wool in the lter I3, which also serves as an oil separator and delivers the excess of oil back to the supply in the tank I I.

Any one of the many types of oil burner controls may be used with this system and none will be described in the interest of brevity. It will be sufficient to refer to "OilHeating Hand Book" by Hans Kunitz, second edition, and The Starbuck Oil Burner Manual, 1941.

Electric power for the liquid fuel burner system described may be taken from the house line 45 and the apparatus shown in the diagram will bev understood from thev following description of the operation.

When the room thermostat or boiler control 46 calls for heat Minneapolis-Honeywell R. 11'7 relay 4'I will be energized and close an electric circuit to the delayed action switch 48 allowing current to iiow to the oil heater 20 and the ignition transformer 49. After a delayed action, for example, twenty-uve seconds, switch 48 will close the circuit to motor 22, which will start the secondary air fan or blower 23, the primary or atomizing air pump 24 and the oil pump 25. While the pump 24 is building up the necessary pressure in the chamber I2, oil from the pump 25 is recirculated through the bypass, and the heater 20 is condi- 1 tioning the oil in the pipe I9 and warming up the associated parts of the burner.Y When the pressure in the chamber I2 reaches the selected amount the Sylphon 44 will be compressedand the piston valve 43 will cut out the bypass 42 and connect up the oil line leading to the nozzle I8. las the mixture of air and atomized heated oil is discharged from the oriilce 28 of the nozzle, sparks from the electrodes 2I ignite it and the ilame is further fed by the supply of secondary lair' delivered by the fan or blower 23 through the draft tube I6. After a short interval relay 4'I will shut off the current to the ignition transformer 49. The resistance of the heater element 20 increases with the rise in temperature and the wattage drops to .the selected limit for the particular design.

Mention of Minneapolis-Honeywell R 117 relay is merely by way of example. Many other controls can be used and some other controls must be used when the ilre adjusting apparatus, later described, is associated with the burner.

Modulatz'ng the fire The operation of the apparatus described is preferably modified by means to increase the fire after itis started and then modulate the re according to the demand for heat. One embodiment of means to that end includes an air motor comprising a cylinder 50, equipped with a piston 5I whose piston rod 52 runs through the guide 53 and has one arm 54 connected by a link 55 with the rotating shutter 2'I of the secondary air fan or blower and another arm 56 connected by a link 51 with a lever 58 on the oil pump 25 by which its capacity may be adjusted and enlarged as the shutter 2'I is opened to increase the delivery of secondary air by the fan or blower 23.

The piston 5I is normally urged to the position shown by a spring 59 and its limit in that direction is determined by a low fire stop 60, its limit in the other direction being determined by a high re stop 6I, both adjustable on the piston rod 52' and made fast by set screws or the like.

In order to move the piston against the resistance of spring 59, air from the chamber I2 is conducted by a pipe 62 and delivered to a head chamber 63 in the air end of the cylinder 50 fromwhich it passes by a port 64 into the cylinder and exerts its pressure against the piston 5 I. Ihe length of the pipe 62 and the adjustment of a needle 65 will make the flow of air involve the time interval desired for response to change in demand and the supply of air and oil will be increased or decreased in relation to the pressure permitted to build up against the piston head, this function,

however, being limited by the adjustment of low re stop 60 and high re stop 6 I. In some designs the length of the pipe 62 will have a negligible effect and the control will be effected chiefly by adjusting the needle valve 65.

With this arrangement the burner will start with a very small flame and gradually build up to the required size, as determined by the dearm 1|.

device 68 should drop or increase, the port 18 will.'

pneumatic temperature or pressure device 88, connected with the cylinder 88 by a pipe 68. When the temperature or pressure of the device 88, or the space to which it is subject, reaches the point at which it is set, the arm 1| of the device 88 will uncover an orifice 18 in the pipe 68, allowing some air to escape, thus lowering the pressure in the cylinder 88 and allowing the piston to move toward the air end of the cylinder under the action of the spring 58, thus reducing the supply of secondary air and oil. The piston will adjust itself to some poiht between high fire and` low fire positions, depending on the demand indicated by the If the temperature or pressure at the be opened or closed correspondingly and, hence, the fire will be adjusted to correspond with the demand.

The device 68 may be any pneumatic control Jthat will open a port on an increase of tempera- 'ture or pressure and bleed the air from the line 68 to the atmosphere, or close the port on a decrease of temperature or pressure, such, for example, as Minneapolis-Honeywell L-092D. These devices are available in a number of, scale ranges and may be used as a warm air control by mounting in the ai stream, as an immersion aquastat capplate84,securedinplacebyboltsandcar- 'rying an air pressure gauge 88.. 'lhe bronze wool which really forms the filtering and oil separating elements of thefllters I8 and I4, fills the spaces above the draft tube divided by the wall 84 and closed by the cap 84. Removing that cap permits access for cleaning the bronze wool, which should be done at suitable periods by removal and washing in kerosene or some similar solvent.

, The upper portion of the draft tube at the left in Fig. 4, opens into the secondary air fan or blower casing I8 which is generally eccentric with respect to the fan or blower 28, but affords direct and proper communication for air from the blower into and through the draft tube I8.

Just below the fan casing I8 and opposite to the draft tube the main housing has an opening closed by a cap 86, into which the air tube I1 is fitted by inserting it in the liquid to be controlled or as the steam pressure control, by mounting it in the boiler water just below the water line. The boiler water temperature changes with the steam pressure in accordance with familiar steam tables. As these devices and their applications are familiar, specific disclosure is omitted in the interest of brevity.

Main housing Referring to Figs. 2, 3 and 4, it will be seen that thev bottom of the main housing is formed by a base 12, having a-'downturned edge 18, and a machined rib 14 on its upper face to receive and be secured to the bottom of the generally rectangular wall 15, which surrounds the lubricating oil space and with the base forms the oil tank or reservoir II.

Just above the lubricating oil tank, and at the right 4in Fig. 3, there is a hollow cylindrical projection 16, open at 11, to receive the air operated shut-off valve for the oil supply.

Above the projection 16 is a larger hollow cylindrical projection 18, the right side of which, in Fig. 3, is formed lby the slotted wall 28 and the left side of which is formed by the partition wall 18, which is curved at 88 to form the throat or entrance to the Siroco fan or blower 23.

The draft tube |6 intersects the main housing somewhat below the mid portion, and the lower wall 8|, Fig. 4, of the draft tube extends across the main housing above the lubricating oil tank and, in effect, forms the upper portion of the chamber for primary or atomizing air.

Referring to Figs.v 3 and 4, it will be seen that the sides of the main housing are bulged at 82 and 83 .to form passages upwardly around the draft tube and leading to the space for the filters I3, I4 (Fig. 1) which is closed at the $0? by a at the end opposite to that connected with the nozzle |8. The cap also carries an appropriate nipple, etc., 81 for connection with the air pipe 82, thus establishing the complete air line from the primary or atomizing air pump to thenozzle.

At each side of the nipple 81, and slightly above, are open insulated fittings 88 to admit wires 88, the inner ends of which are secured to the electrodes 2| by nuts88 (Fig. 4).

Beneath the nipple 81 the cap 86 has an opening 8| to admit the heater tube 82 which surrounds the heater 28, and the oil line I8, leading to the nozzle I8. Suitable mounting for the electrical connections and the end of the oil pipe I8 are provided by a large cast fitting 8l, secured to the cap 88. I Forked pedestals 84 (Figs. 3 and 4) have openings 88 and 8 8 to receive the air pipe I1 and the heater tube 82 and clamps 81 to receive the in- -sulatirlg tubes 88 for the electrodes 2|. Projections 88 on the clamps 88 and a leg |88 engage 40 the inside of the draft tube and form a support for the assembly bound together by the pedestals 84, By rnoving the fastenings for the cap 86 this assembly, called in practice the drawer assembly, maybe withdrawn as a unit from the draft tube. 'I'he delivery end of the draft tube is equipped with' a suitable conversing fitting |8| (Fig. 4) to direct the secondary air nagainst the mixture of oil and primary air discharged from the nozzle I8. The detailed construction of the nozzle, its connection with the primary air pipe I1, the oil pipe I8 and its operation in use will be sufilciently clear from the enlarged section in Fig. 5, without specific description.

'I'he rectangular portion 18 of the main casing surrounding the lubricating oil space, is provided at one side in Fig. 2, with a non-breakable sight glass |82. through which' the lubricating oil can be readily observed in order. to maintain it at the appropriate level indicated by the line |83.

The size of the orifice. the spray angle and such like will vary with conditions and personal preference.

The air operated shut-of valve for oil Referring to Fig. 3, it will be seen that the cylinder 48 of the air operated piston valve, described in connection with the diagram, Fig. 1, has a reduced portion |84, received in and secured fast to the hollow iiange of a disk |88, bolted to the main casing to close the.opening 11. The Sylphon bellows 44 has one end |81 soldered, or otherwise properly secured to the inner face of the disk |86 and its opposite closed end |88, cooperates with' the cartridge shaped plunger |88, the bottomY of which acts directly on the stem m'of the piston valve and the wan or which telescopes'over the nipple ||I on the cylinder 40. The oil pipes 39 and 4| and the bypass pipe 42 are secured to the cylinder 40 by nipples ||2, ||3 and ||4, respectively (Fig. 3) which connections are threaded to nipples, which in turn, are threaded into openings forming proper communication with th'e interior'of the cylinder 40, which will be understood without specific description. The right end of the cylinder 40 in Fig. 3 is closed by a screw-headed cap ||5 which serves to compress a spring ||6 against the end of the piston 43 and normally urge it to the position shown.

When pressure of the air in the chamber 2 the spring ||6. When the pressure in the chamber |2 is relieved, the spring ||6 will move the parts back towards the position shown in Fig. 3

and under proper conditions' will shut off the oil from the burner and connect'the oil pipe 33 with the bypass 42, Fig. 1.

The shut off movement of the piston 43 produces a partial vacuum in the right end of the `cylinder 40, which is relieved through the passage 9 (Fig. 3)` by ow from the nozzle and prevents dripping at the orice.

Y The notor and secondary fan The casing of the electric motor 22 is provided is preferably of the Siroco type.

The primary air pump Referring to Figs. 3, `7, l1 and 12, it will be seen that the primary air pump casing is formed by two disks |2| and |22, spaced apart and sesured to a cylindrical ring or shell |23 within which is an eccentric rotor |24, keyed to a shaft |25, journaled in the hub portions |26 and |21 of the disks |2| and |22. The disk |22 has a cylindrlcal flange |28, which telescopes ywith and is p secured to the boss |29 on the slotted wall 26 of the housing.

'I'he eccentric rotor |24 is provided with four slots |30 (Fig. 11) to receive reciprocating vanes |3|, the outer edges of which engage the inner perimeter of the ring |23, and serve to propel the air through the pump. The vanes are urged radially outward by springs |32 surrounding guide pins |33, extending through the shaft |25.

As will be seen from Fig. 7, the air inlet |34 in this instance is through the disk 22 and leads to a curved inlet passage |35 (Fig. 12) open to the in'side of the pump chamber. The outlet |36 for air leads through the periphery of the disk |2| to a curved passage |31 (Fig. 11) in communication with the pump chamber. e

From this it will be apparent that rotating the shaft |25 clockwise in Fig. 11 win cause the air to enter' through the inlet passage |34 and be t compressed by th'e vanes |3| successively and driven through the outlet intothe pipe 30 leading to the main housing, Fig. 1.

The disk |22 is provided with a bushing |38 in which the shaft |25 is journaled, andthe disk is provided with a curved bypass inlet |39 (Fig. l2) communicating with a cored passage |40 leading to the curved inlet passage |35. Flow through r this bypass is controlled and adjusted by the screw valve A|4| locked in place by the nut |42.

By adjusting that valve the bypassed air can be cut of! or increased in any amount. to regulate the delivery of the pump to anything within its capacity.

As heretofore stated, the screw valve |4| is adjusted to maintain some normal pressure in the chamber I2, for example a normal pressure within the range of ilve to twelve pounds. A feature ofthe present form of the invention, however, is that the moving parts of primary air pump 24 are dimensioned with such liberal clearances that plentiful lubrication of the pump interior is required to cause and maintain they normal pressure. If internal lubrication of the pump is non-existent or is insufllcient to adequately seal the clearance spaces, the pump will function at a lower level of elciency, the pressure in the chamber l2 then being too low to contract the Sylphon 44 to close the fuel pump bypass but high enough to force lubricant through pipe 33 to the air pump.

Clearance may beY provided between any of various cooperating surfaces. Thus clearance may be between the edges of blades |3| and adjacent surfaces of discs |2| and r|22 (Fig. '7), or between faces of rotor |24 land corresponding faces of the discs |2| and |22, or between faces of blades |3| and corresponding faces or walls of slots |30. (Fig. ll.) The provision of such clearance requires only the ordinary skill expected in this art, especially since the pressure created by the pump running without lubricant is not critical. To prevent actuation of the Valve piston 43, it is suilicient that the pressure from the pump drop to any value below ve pounds and a minimum pressure of only one pound will lift oil from the sump a vertical distance of over thirty inches. Thus the clearance in the working parts of the pump may be such as, in the absence of lubricant, to drop the output pressure to any value between one and five pounds.

The oil pump Refer to Figs. 3, 7, 8, 9 and 10.

The casing of the oil pump 24 is formed by a cylinder |43 integral with the hub |26 of the primary air pump and a disk-like cylinder head |44 secured by bolts. Within this cylinder |43 is a bronze rotor |45 keyed to the end of the shaft |25 by a pin |46. Adjacent to the end of the shaft |25, the rotor is provided with a transverse bore |41 in which is a double ended piston |48, the intermediate portion of which is cut away to form a notch |49, which receives an eccentric pin 50, projecting through the disk |5| which bears against the end of the rotor |45.

Refer to Fig. l0.

The inlet for oil |52 through the cylinder 43 is in communication with a curved inlet' passage |53 extending partially around the rotor |45 coincident withlthe cylindrical bore |41. 'Ihe outlet for oil |54 in the cylinder |43 communicates with a curved outlet passage |55, also coincident with the bore |41 in the rotor |45.

From this it will appear that when the shaft |25 is driven, the ldouble ended piston |48 will reciprocate back and forth and oil entering the inlet |52 will be forced out the outlet |54.

By changing the eccentricity of the pin |50, the stroke of the double ended piston can be changed and thus the capacity or the delivery of the oil pump can be varied within the limits of the design. To accomplish this adjustment, the disk |5|, bearing the pin |50, is provided with a slot |55 (Figs. 3a, 9 and 10) Whichreceives guiding pins |51, carried by the head |44. And these pins allow the disk rectilinear motion crosswise to the axis of the shaft |25, but no rotation.

'I'he end of the pin |50, opposite to that which engages the disk |5|, is provided with a socket |58, which receives a crank pin |59 on the shaft |60, the reduced end portion |6| ofwhich projects through the stuffing box |62 on the head l and is equipped with the lever 58.

By rotating the shaft |60, the crank |58 can be made to change the eccentricity of the pin |50 from nothing to the extreme within the range of the design and to that extreme in either direction, thus the stroke of the piston can be adjusted from neutral to maximum and the same pump may be made to act as a pressure pump or a vacu- 'um pump or, in other words, the intake and exhaust sides can be reversed by simply rotating the shaft |60 and the length of the stroke in either phase of operation can be adjusted from zero to a maximum.

In this particular liquid fuel burner system the pump will not be reversed, but it will' be adjusted from various small capacities to the largest with- 5 motor to shift the adjustment 1ever58 in the direction for still greater increase in 'oil ow.

in the limit of the design, and that is accomplished in the organization shown in Fig. 1 by the operation of the lever 58 through air pressure or the spring 59 in the cylinder 50.

Referring again to Fig. 3, it will be seen that the shutter 21 for the secondary air is rotatably mounted on the cylindrical flange |28 by which However, the building up o f primary air pressure due to the-increased oil pressure does not appreciably affect the operation of the modulating motor because it merely causes the piston to move outwardly a little more than it would other- Wise, but this excess movement is very quickly compensated for by the reduced temperature demand at the thermostat.

By operating the adjustment and secondary air shutter with of the oil pump air becomes automatic for increasing the fire after a. start and for modulating -it in accord with the varying requirements for heat.

'Ihe oil pump also has its advantages when used without the automatic adjustment and some will desire to have it so. In such instances the cost can be somewhat reduced by replacing the shaft |60 with its crank |59, the lever |58 and associated. parts, by a screw threaded in` the cylinder and cooperating withy the pin |50, to shift it in accord with the length of the stroke or capacity of the pump required. In that in stance, and in other instances, some Wi11 wish to the pump assembly is mounted on the main housing.. The connection allows free rotation of the shutter without unnecessary play in operation by the link 55 when the modulating motor is.

used, or by other Vmeans when the modulating motor is not used. The cylinder 50 is supported by a bracket |63 bolted to the main housing at |64 and provided with a clamp |65made fast by bolts |66. This means of mounting it affords ready adjustment in 60 and 6|.

For convenience in manufacture 'and assembly the three pumps and the motor for driving them have a common axis. The shaft for the primary air pump and the oil pumpis in one piece and is connected with the shaft of the secondary air fan 23 by a yielding flexible coupling |61. A

The oil pump here disclosed has a positive displacement and, being double acting, its delivery for a given adjustment and speed is constant for all practical purposes. Fory that reason, when it is used as a metering pump the apparatus can operate successfully on No. 5 oil.

'I'he use of a double ended piston also has the advantage of giving the required capacity in very small size.

When the' stroke of the piston is increased by movement of the lever 58, as described, the -de livery of Aoil to the nozzle is positively increased. 'I'he increased delivery of oil results automatically in increased air pressure in the air line as required for proper atomization of the increased oil flow. In a domestic oi1 burner adjusted for a normal pressure of five pounds in the primary chamber |2, the pressure in the chamber has been observed to build up as high as ten pounds when the rate of fuel delivery is substantially increased.

One reason for the automatic rise in pressure is that the increased .flow of oil at the burner nozzle offers increased resistance to air ow from the nozzle thereby tending to increase air ypressure in the air line back of the nozzle.

At first thought it would seem that the increase 4,5 under pressure to the primary air line, a positive connection with the stops 40 provide a spring |68 (Figs. 8 and 9) to constantly urge the pin |50 in one direction.

The automatic increase from low fire to high re position will not work with Minneapolis- Honeywell Relay 117 because the stack control will throw the device on safety at low fire position. In such stances the R 117 relay should be replaced by oneof the many other controls as, for example, those actuated by the light of the flame instead of the stack temperature.

I claim as my invention:

1. In an oil burner capable of operating with various grades of fuel oil including low grade fuel oils, the combination of anozzle, fuel and primary air lines to the nozzle, means, including a draft tube telescoped over a portion of said lines,

for supplying secondary air to the space around the nozzle, a primary air pump for forcing air displacement oil pump for supplying metered quantities of oil through the oil line to the nozzle regardless of the viscosity of the oil, and valve means for bypassing oil from the delivery side of the oil pump to the intake side thereof whenever the primary air pressure is below a predetermined value, said last-named means being responsive solely to primary air pressure.

2. In an oil burner capable of operating with various grades of fuel oil including low grade fuel oils, the combination of a nozzle, fuel and primary air lines to the nozzle, means, including a draft tube telescoped over a portion of said lines, for supplying secondary air to the space around the nozzle, a primary air pump for forcing air under pressure to the primary air line, a positive displacement oil pump for supplyingmetered quantities of oil through the oil line to the nozzle regardless of the viscosity of the oil, and valve means for bypassing oil from the delivery side of the oil pump to the intake side thereof Whenever the primary air pressure is I below a predetermined value, said last-named means being responsive solely to primary air pressure and means for automatically causing a the pressure of atomizing air, the adjustment of fuel and total4 various' grades of fuel oil including low grade fuel oils, the combination of a nozzle, fuel and metered quantities of oil through the oil line to the nozzle regardless of the viscosity of the oil,

and valve means for bypassing oil from thedelivery side of the oil pump to the intake side thereof whenever the primary air pressure is below a predetermined value, said primary air pump having clearances such that the maximum air pressure developed when operating with insufllcient iubrication is less than that required to operate i the valve means to connect the discharge side of the oil pump to the nozzle.

4. In an oil burner capable of operating with fuel oils, the combination of a nozzle, fuel and primary air lines to the nozzle, means, including a draft tube telescoped over a portion of said lines, for supplying secondary air to the space i around the nozzle, an electric motor, a secondary air blower,` a primary air pump and a positive displacement oil pump arranged in tandem and driven directly by said motor, a main housing having an air chamber around the draft tube,

. means for delivering air from the primary air pump to the air chamber and thence to the primary air line leading to the nozzle, and means responsive to the pressure in the chamber for bypassing oil from the delivery side of the oil pump to the intake side thereof until said air t chamber pressure reaches a predetermined value` after which said last-named means closes the bypass and directs the oil from the oil pump directly to the nozzle.

5. In adevice of the class described, a burner -various grades of fuel oil including low grade l having a nozzle, a positive displacement oil pump for supplying metered quantities of oil under pressure to the nozzle, a piston valve controlling the supply of oil to the nozzle, an air pump for supplying air to the burner, an air chamber receiving air from the pump, a lubricant tank communicating with said air chamberl and subject to pressure therein. a passage to convey lubricant from said lubricant tank to the intake side of said air pump for sealing the work- -ing parts of the air pump. and means for operating the piston valve including an air motor subject to pressure of the air in said air chamber.

6. In a device of the class described, a burner. an oil supply system including an oil pump to deliver oil to said burner, a bypass across said pump, valve means movable in one direction from a position opening said bypass and cutting off said burner to an operating position cutting oir said bypass and placing said oil supply system in communication with said burner, said valve means when moved in saldj opposite direction providing an expanding space to withdraw oil from the burner after the burner is cut oil', an air supply system for delivering air to said burner, and .means responsive to the pressure in said air supply system to move said valve means in said one direction in response to rise inl the supply air pressure to a predetermined magnitude and to move the valve means in the opposite direction when the supply air pressure drops to a lower magnitude. l

7. In a device of the class described, a burner,

walls closing a space ypartially iilled with a body` of lubricant, an air pump to deliver air to said burner, the output side of said pump communicating with said space to build up pressure thereim passage means from said body of lubricant in said space to deliver lubricant to said pump in response to relativelylow pressure in the space, an oil supplysystem to deliver fuel to said burner, a valve means movable from a iirst position cutting off said burner to a second position placing said oil supply system in communication with the burner, and means to move said valve means from said first position to said second position in response to relatively high pressure on the output side of said air pump, said responsive means being non-responsive to said relatively low pressure, said air pump having such clearance in its working parts as to develop said relatively high pressure when the working parts are freely lubricatedand to develop a pressure between said relatively high pressure and said relatively low pressure when the pump is inadequately lubricated whereby the need for replenishment of said'body of lubricant will be signalized by failure of the burner to operate.

8. In a device of the class described, a burner,

means to deliver fuel to the burner, an air pump, passage means from the output side of said air pump to said burner, said pump having such clearance in its working parts as to develop re1- atively low pressure in said passage means in the absence of substantiallubricant in the pump and to develop relatively high pressure with substantial lubricant in the pump, a lubricant reservoir communicating with the inlet side of said pump to deliver lubricant thereto, said lubricant reservoir communicating with said passage means to receive lubricant therefrom whereby lubricant may iiow in a cycle to continuously lubricate the pump, and valve means responsive to pressure in said passage means to place said burner in communication with said fue; delivery means when said relatively' high pressure exists in the passage means and to cut oil? the burner when said relatively low pressure exists in the passage means whereby failure of oil circulation through the pump will be signalized by failure of the burner to operate.

9. In a device of the class described, a burner, means to deliver fuel to the burner, an air pump. passage means from the output side of said air pump to said burner, said pump having such clearance in its working parts as to develop re1- atively low air pressure in said passage means in the absence of substantial lubricant in the pump and with the presence of substantial lubricant in the pump to develop relatively high air pressure in said passage means, a iilter in said passage means, a lubricant reservoir communieating wtih the inlet side of said air pump to deliver lubricant thereto, said reservoir communieating With said passage means to receive lubricanttherefrom whereby lubricant may now in a continuous cycle to lubricate the pump and to circulate through the filter, and valve means responsive to air pressure in said passage means to place said burner in communication with said fuel delivery means when said relatively high air pressure exists in the passage means and to cut .0E the burner when said relatively low air pres.. sure exists in the passage means whereby failure of oil to circulate through the lter will be signalizedby failure of the burner to operate.

10. In a device of the class described, a burner, means to deliver fuel to the burner, an air pump, passage means from the output side of said air pump to said burner, said pump having such liberal clearance in its working parts as to develop relatively low air pressure in said passage means in the absence of substantial lubricant in the pump and with substantial lubricant present in the pump to develop substantially higher air pressure in the passage means, a chamber included in said passage means, said chamber containing a body of liquid lubricant, a filter medium in said passage means, walls in said passage means to cause liquid to separate from said filter medium and to direct the separated liquid to said body of lubricant, a passage from said body of lubricant in said chamber to deliver lubricant to said pump and thereby cause the lubricant to be delivered to said filter means for filtering of both the air and the lubricant, and valve means responsive to air pressure in said passage means to place said burner in communicationwith said fuel delivery means when said relatively high air pressure exists in the passage and to cut olf the burner when said relatively low air pressure exists in the passage whereby failure of substantial lubricant to cycle through the pump and filter medium will be signalized by failure of the burner to operate.

11. In a device of the class described including a burner, an oil supply system to supply fuel to said burner and an air supply system to supply air to the burner, the combination therewith of a valve controlling the flow of fuel from said oil supply system to said burner, said valve having a cylindrical body with an inlet port and an outlet port in the cylindrical side thereof, a piston in said body movable in one direction to place said inlet port in communication with said outlet port and in the opposite direction to out said inlet port off from said outlet port and to draw oil inward through said outlet port, yielding means to urge said piston in said opposite direction, and means to move said piston in said one direction in response to pressure from said air supply system.

12. In a device of the class described including a burner, an oil supply system to supply fuel to said burner and an air supply system to supplyl air to the burner, the combination therewith of a valve controlling the iiow of fuel from said oil supply system to said burner, said valve having a cylindrical body with an inlet port and an outlet port in the lcylindrical side of the body, said inlet and outlet' ports being at points spaced longitudinally of the body, a piston in said body movable in one direction to place said inlet port -in communication with said outlet port and in the opposite direction to .cut said inlet port oil' from said outlet port and to draw oil inward through said outletl port, yielding means to urge said piston in said opposite direction, and means to move said piston in said one direction in response to pressure from said air supply system.

13. In an oil burner capable of operating with various grades of fuel oil including low grade fuel oils, `the combination of a nozzle, fuel and primary air lines to the nozzle, means vfor supplying secondary air to the space around the nozzle, a primary .air pump for forcing air under pressure to the primary air line, a positive displacement oil pump for supplying metered quantities of oil through the'oil line .to the nozzle regardless of the viscosity of the oil, and valve means for bypassing oil from the delivery side of the oil pump to thev intake side thereof whenever the primary air pressure is below a predetermined value, said last named means being responsive to primary air pressure and independent of fuel oil pressure,

14. In an oil burner capable of operating with various grades of fuel oil including low grade fuel oils, the combination of a nozzle, fuel and primary air lines to the nozzle, means including a blower and a motor for supplying secondary air to the space around the nozzle, a primary air pump also driven by said motor for forcing air under pressure to the primary air line, a positive displacement oil pump for supplying metered quantities of oil lthrough the oil line to the nozzle regardless of the viscosity of the oil, and valve means for bypassing oil from the delivery side of the oil pump to the intake side thereof whenever the primary air pressure is below a predetermined value, said last named means being responsive to primary air pressure and independent of fuel oil pressure.

15. In an oil burner capable of operating with various grades of fuel oil including low grade fuel oils, the combination of a nozzle, fuel and primary air lines to the nozzle, means for supplying secondary air to the space around the nozzle, a primary air pump for forcing air under pressure to the primary air line, a positive displacement oil pump for supplying metered quantities of oil through the oil line to the nozzle regardless of the viscosity of the oil, and valve means for bypassing oil from the delivery side of the oil pump to the intake side thereof and for shutting olf the supply of oil to the nozzle whenever the primary air pressure is -below a predetermined value, and forl delivering oil from the oil pump t0 the nozzle and shutting off the oil bypass whenever the primary air pressure is above said predetermined value, said last named means being responsive to primary air pressure and independent' of fuel oil pressure.

16. In an oil burner capable of operating with various grades of fuel oil including low grade fuel oils, the combination of a nozzle, fuel and i' tities of oil through the oil line to the nozzle rer gardless of the viscosity ofthe oil, and valve means for bypassing oil from the delivery side of vthe oil pump to the intake side thereof and for shutting -off the supply of oil to thenozzle whenever the primary air pressure is below a predetermined value, and for delivering oil from the oil pump to the nozzle and shutting oir the oil bypass whenever 'the primary air pressure is above said predetermined value, said last named means comprising a body member having an inlet port for receiving oil from the oil pump, a discharge port connected to the nozzle and a by- Dass port, a stem member movable within the body member in response to primary air pressure and independent of fuel oil pressure for connecting the inlet port to the bypass port and for shutting on' the discharge port lwhen the stem member is at one limit of its travel, and for connecting the inlet port to. the dischargeport and shutting lofi! the bypass port when the stem EARL JOSEPH SENNINGER.

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