US2122986A

US2122986A - Oil burner

Info

Publication number: US2122986A
Application number: US696562A
Authority: US
Inventors: William C Mason
Original assignee: Individual
Current assignee: Individual
Priority date: 1933-11-03
Filing date: 1933-11-03
Publication date: 1938-07-05
Anticipated expiration: 1955-07-05

Description

July 5, 1938. w. c. MASON 2,122,986

OIL BURNER Filed Nov. 5, 1933 5 Sheets-Sheet l July s, 193s. w C, MASON 2,122,986

OIL BURNER Filed Nov. 5, 1933 5 Sheets-Sheet 2 /Nz/E/v T01? WILLIAM L', HAMM( A 7' 70k/VE Ys W. C. MASON July 5, 1938.

lOIL BURNER Filed Nov. 5, 1935 5 Sheets-Sheet 3 July 5, 1938. v w, MASQN 2,122,986

OIL BURNER Filed Nov. 3, 1933 5 Sheets-Sheet 4 ,ff 575 [l ll. i @i j? /NVf/v To@ WILLIAM 7, NASN ,Gaza /f M f ATTORNEYS w. c. MASON 2,122,986

OIL BURNER Filed Nov. 5, 1933 fSheets-Sheet 5 4 7- TANE Ys Patented `luly 5, 1938 011. BURNER William C. Mason, Albany, N. Y.

Application November 3, 1933, Serial No. 696,562

12 Claims.

My invention relates to oil burners and particularly to those of the general type described in my copending application Serial No. 577,314, filed November 25, 1931, in which the oil is aspirated and atomized by means of steam and introduced therewith into the combustion chamber. It also relates to novel means for generating the steam and novel means for controlling the operation of the burner.

One of the objects of my invention is to provide, in connection with an oil burner, a simple and inexpensive device for electrically generating steam for the purpose of aspirating and injecting the oil into the combustion chamber in the form of a very fine vapor. Another object is to provide a simple and novel means for controlling the generation of steam. Another object is the provision of a novel means for initially starting the oil burner and for re-igniting it in the event it is, forany reason, extinguished. Another object is to provide a device of the character described in which all danger of explosion, due to the accumulation in the combustion chamber of explosive gases, or to excessive steam pressure, is eliminated. Another object is to provide a small compact unit in which is embodied substantially all of the controls necessary to operate the device safely and efficiently. A still further object is to provide control means which will not only be positive in operation but which will, when the necessity f'or functioning arises, act quickly.

With these objects in view my invention includes the novel elements and the combinations and arrangements thereof described below and illustrated in the accompanying drawings in which- Fig. l is a plan view of my invention with certain parts removed;

Fig. 2 is a fragmentary vertical section through a ilre pot or combustion chamber for a water heater showing details of one of the controls;

Fig. 3 is a fragmentary plan view of a control detail; K

Fig. 4 is a fragmentary vertical section, partially in elevation, of a steam generator showing a portion of the control means;

Fig. 5 is a. perspective view of a control switch;

Fig. 6 is a plan view, partially in section, of a modified type of control switch;

Fig. 7 is a plan view of the control panel showing some slight modifications in the arrangement thereof shown in Fig. l;

Fig. 8 is a fragmentary enlarged section in the plane 8--8 of Fig. 4;

Fig. 9 is an enlarged longitudinal vertical section through a nozzle element;

Fig. 10 is a greatly enlarged, vfragmentary sectional view of the discharge end of the nozzle;

Fig. 10a is an elevation view of the discharge end of the nozzle;

Fig. 11 is a section of Fig. 9 in the plane I I-I I;

Fig. 12 is an enlarged fragmentary vrear view of the nozzle and a mounting therefor;

Fig. 13 is a sectional plan view of a control detail;

Fig. 14 is a fragmentary vertical section of an oil filter;

Fig. 15 is a section of Fig. 13' in the plane I5-I5;

Fig. 16 is a perspective view of a detail;`

Fig. 17 is a perspective view of a water valve detail;

Fig. 18 is a fragmentary vertical section through the water valve;

Fig. 19 is a plan view of the water valve spring;

Fig. 20 is an elevation view of the water valve spring;

Fig. 2l is a fragmentary schematic perspective view of my device showing the connections of the oil and `water pipes thereto; and

Fig. 22 is a wiring diagram.

Referring to the drawings, I represents, generally, a steam generator comprising a lower base element 2 and an upper base element 3 between which is secured a cylindrical enclosing element 4, the upper and lower bases being secured together by means of bolts 5 (see Figs. 1, 4 and 21) Integral with the lower base 2 is a cylindrical depending portion 6 through which the water is introduced into the generator. The portion 6 is provided with a central passage 'l extending therethrough. Thispassage varies in size and the smallest portion thereof is at about the center of the portion 6. Above the center, the passage is slightly enlarged, as shown at 8, to receive a needle valve 9 which is seated at the upper end of the smallest portion of the passage 1. Above the slightly enlarged portion 8, the depending portion of the base is counter-bored, as shown at I0, to receive a helical spring II which is compressed between the head I2 of the needle mentary portion provided in the element 6. Be-

and is provided with a circumferential groove which communicates with thevcounter-bored portion I1 by means of an opening 2|. Surrounding the grooved portion 26, is a collar 22 provided with a nipple 23 exteriorly threaded at 24l to adapt it to be connected to a water supply pipe, and interiorly threaded, as shown at 25, to receive a hollow plug 26 forming part of the ball check valve 21. The ball 21| ordinarily seals the water passage 28 in the plug 26 by. compression .of a spring 29. v 'I'he collar 22 is secured in position about the redu'ced portion of the depending element 6 by means ofA the'cap I6 and

suitable gaskets

30 and 3| are provided at the top and bottom in order to insure a water tight connection.

A ball 32 rests on top of the needle valve 9, and

' the needle valve 9 is normally held in closed position by means of a slide valve 33 which is adapted to be reciprocated across tl-: opening 34 in the lower base.

The interior portion of the lower base 2 is threaded, as shown at 35, to receive the cup or disc 36 which is provided with a peripheral ange 30 31 within which is seated a carbon electrode 38.

A star spring 39, shown in detail in Figs. 19 and 20, is interposed between the `disc 36 and the slide valve 33 and serves to retain the slide valve 33 Fin yielding contact with the base 2.

' Fig. 18. When the ball 32 is in the depression 40 the needle valve 9 is raised from its seat by spring Il so, that water can ow upwardly through the passages 8 and il and under the slide valve into the generator. The slide valve may comprise a rectangular metal block having a cross-shaped recess 11 at one end adapted to receive the operating or connecting rod 16 with a nut 19 thereon. To provide for adjustment. or the slide valve, it is provided, near the' end opposite the connecting rod with avertically extending threaded hole adapted to receive the adjusting screw 4|. This screw extends through the slide valve and it may be so adjusted that its 4 lower end rides on the upper portion of the base v2, Aas best shown in Fig. 18, thus slightly raising or tilting the block as here illustrated.

The disc 36 is perforated, as shown at 42, and the carbon electrode 38 is provided with vertically extending passages 43 through which the water iflows upwardly into the steam generator.

'I'he carbon electrode 36 is preferably cupshaped, as shown in Fig. 4, and is provided with a pluralityof circumferential openings or pas- ,sages 44 for the free ilow of water therethrough.

The electrode 38 is provided with a central stud l or stem 45 of porcelain which is received within an opening in the upper carbon electrode 46 and which serves not only to maintain the electrode 46 concentric with the electrode 36 but laterally and vertically spaced therefrom, as shown at 41 and 48, respectively. The electrode 36 is grounded. 'I'hreaded into the electrode 46 is a metal conductor 49, the upper portion of which is enclosed in an insulating collar 56 extending outwardly through the upper base 3. A suitableA packing nutl 5| is provided around the insulat-l ing collar 50 where it passes through the upper base 3 and nuts 52 are threaded on the top of the conductor 49 to facilitate the connection of an electrical conductor thereto.

In the embodiment of my invention 'illustrated in the drawings, the burner jet orvnozzle, represented generally by the numeral 53, is located on the upper base 3. 'I'he details of the nozzle are shown in Figs. 8, 9, 10, 11 and 12. A.v boss 54, shown in section in Fig. 8, is cast on the top of the upper base 3. The passageway (see Fig. 8) extends upwardly through this boss to the nozzle 56. 'I'he nozzle proper may be very small and except for the tip is preferably square or rectangular in cross section. It may be from 1A" to 1% square and is conveniently made as follows:

A square rod is cut to the desired lengthto form the nozzle blank and the discharge end is turned to the shape shown in Fig. 10, the extreme end portion being cylindrical. The blank is then drilled axially from the rear end almost through to provide a steam passage 51 of comparatively large size. A comparatively small passage 51 is then drilled from the discharge end in axial alignment with and to meet passage 51. A second passage 59, for oil, is also drilled axially of the blank and in spaced relation to passage 51. 'Ihis passage terminates short of the rear endof the blank. Transverse passages and 66 are then drilled to meet

passages

51 and 59, respectively. The passage 60 is preferably counter-bored for a short distanceand a small section of screen 6| pressed therein to serve as a illter for the steam. 'I'he rear end of passage 51 is sealed, preferably with a screw plug 62 of low melting point metal which is threaded therein. In case of flre about the exterior of the nozzle this plug will fuse and the fuel supply to the nozzle will be cut oif because the steam used to aspirate it will escape through the opening thusv provided. A cap 63 having a central opening 63 therein aligned with passage 51' and having an annular recess 64 about the opening 63' on the inner side thereof is then pressed over the cylindrical discharge end of the nozzle blank. .The inner face of the cap is slightly spaced from the end of the nozzle blank as shown at 65. The recess 64 forms an oil chamber endirections and projected into the combustion chamber with the steam. A rectangular V-shaped notch may be provided in the top of the boss 54 to receive the nozzle, as shown in Fig. 8, the

steam passage 55 opening into one side of this notch to register with passage 60 in the nomle, and an oil passage 69 in boss 54 opening into the other side of the notch to register with passage 66' in the nozzle. Gaskets 1|lfand 16' may be interposed between the notch and nozzle and the nozzle securely held in the notch against the gaskets by means of the clamp 1| and screw 12. Oil is aspirated into passage 69 through pipe 13 and air may also be` admitted to passage 63 through pipe 14, as will be later explained, to cut oil.' the supply of oil to the nozzle.

.In Fig. 12 I have shown a modied form of nomle mounting in which thenomle 56 is secured in a squareopening in the boss by means of a set screw 12' which in turn may be locked by pin 12|, thus making it impossible to remove the nozzle without breaking the expanded end of the pin 12| which forms a seal S.

I The cylinder itself which aiaaose Referring now to Fig. 4, the lower base 2 is provided with a hollow nipple 15 through which passes the connecting rod 16 for the slide valve 33. This connecting rod is shown in detail in Figs. 16 and 18. The end of the slide valve opposite the adjusting screw 4| is provided with a cross-like recess or opening 'Il (see Fig. 1'7) The connecting rod 16 is flattened and threaded at one end as shown at 18 and a nut 19 is threaded thereon. The nut l19 fits in the transverse portion of the slot 11 and the attened portion of the rod- 18 ts in the longitudinal portion of the slot 11. The flattened portion of the rod prevents its turning after it is inserted with the nut thereon in the valve and the purpose of the threaded connection with the nut is to provide relative longitudinal adjustment of the rod and slide valve.

The nipple 15 on the base 2 is exteriorly threaded to receive the ilange 80 forming the head of a cylinder in which is enclosed a sylphon bellows; the other head of the cylinder is shown at 8|. may comprise a brass tube 82 is secured between the heads 80 and 8l by means of the cap screws 83.

The interior of the head 8| is provided with a ange 84 which is received within and secured to one end of the bellows 85. The other end of the bellows is sealed by means of the element 86 provided with a peripheral flange 81 and a reentrant center portion 88 which extends around and is laterally spaced from the end oi the connecting rod 16. A head 89 ls provided f on the end of the connecting rod and a helical spring 90 is compressed between a washer 9| beneath the head 89 and the end of the nipple 15. A collar 92 is threaded into the head 8| and. adjustably compressed between the collar 92 and the element 86, is a helical spring 93 which tends to maintain the bellows normally expanded. Passing through the central portion of the collar 92 and threaded into the bottom of the reentrant portion of the element 86, as shown at 94, is a rod 95 the threaded end of which contacts with the head 89 on the connecting rod 16. A removable plug 94 is provided in the upper portion of the head 8| for purging the interior of the expansion chamber of air, and a second plug 95' is provided in the lower portion of head 80 for draining the chamber.

Fig. 'l is a plan view showing the burner controls which lie to the left of the steam generator and expansion chamber, shown in sectional elevation in Fig. 4, and which are operatively connected therewith by the movable rod 95.' rl'fhe general assembly is shown in plan to a smaller scale in Fig. 1 and a portion of the controls is shown in section in Fig. shown in Fig. 7 are conveniently mounted on a molded base B of bakelite or other insulating material in which some of the electrical conductors may conveniently be molded.

Referring particularly to Figs. 1, 1 and 13, the rod 95 is provided at its outer extremity with a collar 96 threaded thereon and whichis secured in place by a lock nut 91. The part 98 is preferably a brass casting secured to the base B and having, ln cross section, the form shown in Fig.

' .13. Supported between the abutments 99 and |00 and retained in a notch in abutment 99 and in the cup-shaped end of a set screw |02 is a flat spring |03 extending in front of the end |04 of rod 95. The screw |02 is adjusted so to compress the spring longitudinally that it assumes a slightly bowed shape. as shown at |03. but will,

13. All of the controlsand an enlarged portion |09 of the rod |05. Be-

tween the enlarged portion |09 and the end |05 of rod 95, the rod |05 is reduced in cross section for a short distance, as shown at H0, and this reduced portion passes loosely through an opening in the sprl-ng U03, the length of the reduced portion of the rod |05 being such as to allow some longitudinal movement of the rod without affecting the spring. The spring |03, near the end opposite that through which passes the rod |05, is provided with a soft rubber cup having a head or button M2 which is merely snapped through an opening in the spring |03 to secure the cup thereto. When the spring is in the position |03 (see Figs. 13 and 15) the rubber cup seals an opening i I3 in the casting 98 which communicates through passage H4 with a pipe 14 which in turn communicates with the oil passage 69 in the boss- 59 on top of the steam generator. When the spring |03 is in the position shown in the dotted lines in Fig. 13 and the solid lines in Fig. '7, air may pass through the pipe 1B into the oil chamber 69, but when the spring is in the position shown by the solid lines in Figs. 13 and 15 the rubber cup efectually seals the opening ||3 so that no air can pass through the pipe 14 into the oil chamber.

Pivotally supported at ||6 is a lever of insulating material H1, one end ||8 of which, contacts, or may contact under certain conditions, with an adjusting nut ||9 on the end of rod |05.

The other end |20 of the lever ||1 contacts through a yielding helical spring |2| with an adjusting nut |22 on rod |23. The rod |23 passes through a gland nut |24 and is connected to a circular flexible-diaphragm |25 secured in a recess in the casting 98 by the element |26 threaded therein, a gasket |21 being provided to maintain a tight joint. The space |28 to the right of the diaphragm |25 is sealed except thatv it communicates with the water supply main through an opening |29 and a pipe |30 (see Fig. 21). A helical spring |3| is compressed between the gland nut and the enlarged inner end of rod |23 secured to the diaphragm |25, and the pressure on the left side of the diaphragm may be adjusted by means of the nut |24.

To the left of the lever, ||1 as viewed in Figs.

7 and 13, is a nat splmg |32, preferably identical I with springA |03. and supported at one end in a notch |33 in a frame |33 of insulating material, and at the other end in the cup-shaped point of a screw |34 threaded into the frame. The screw |34 is so adjusted to effect a longitudinal compression of spring |32 that the spring is supported in a slightly bowed or stressed condition. In alignment with 'the rod |23 is a plunger |85 which is adapted to move back and forthin a recess in the frame |33', and a helical spring |36 is compressed between the head of the plunger |35 and the bottom of the recess in the frame in which it moves so that the plunger is normally pushed to the right by the compression of the spring which is strong enough, in the absence of any pressure on the rod |23, to force and hold the spring |32 in the position shown in the solid lines. The plunger |35 is provided with a reduced portion |31 which passes loosely through the spring |32 and which terminates in the enlarged head |38 adapted to contact with the end of the lever 1. Secured to the spring 32 is a second spring |39 carrying the metal contact |40. A second metal contact |4|, adapted to coact with the contact |40 when the spring |32 is sprung to the position |32', is secured to the binding post |42. A exible electric conductor |43 may extend from the spring |39 to a second binding post |44, as shown in Figs. 1 and 13, but I prefer the arrangement shown in Fig. 7 whereby a ilexible conductor |43' is merely carried to a binding post |44' molded into the base B and thence, through a molded-in conductor X to the main binding post P.

Referring to Fig. 21, |45 is a fuel oil tank which communicates with a float valvev |46 through pipe |41. From the chamber of the iloat valve which maintains the oil at a constant level and preferably about three inches below the nozzle of the burner, the oil flows through pipe |48 into the filtering device |49, the details of which are shown in Fig. 14. The ltering device comprises a hollow cylindrical element |50 which is closed at the bottom by means of the plug |5|, a gasket |52 being interposed between the plug and the cylindrical element |50 to insure a tight connection. Oil flows in through the pipe |48 and downwardly through the passage |53 into the element |50. Interposed between the passage |53 and the plug |5| is a ltering screen |54 which is preferably frusta-conical as shown. The oil passes through the screen and then upwardly through the passage |55 to an adjustable needle valve |56 and thence to a static level in pipe 13, somewhat below` the nozzle of the burner, and from which it is aspirated to the burner by steam as will be later explained. n

To ignite the fuel a spark plug having terminals |51 and |58 is disposed in front of the nozzle. The electrical circuit which includes the spark plug is automatically closed and broken by mechanism which will hereinafter be described but, in order that the same may be more readily understood it seems desirable first to describe the manner in which the steam is generated and the fuel aspirated to the nozzle.

It is -to be understood that the water in the water supply pipe is maintained at a pressure substantiallyin excess of the maximum pressure which will be developed in the steam generator.

Assuming that there is water under pressure in.

the pipe |30 (see Fig. 21) -it is quite evident that this pressure will be exerted on the right hand side of the diaphragm |25, as viewed in Fig. 13. The diaphragm will be pushed or distorted to the left, thus moving the rod |23 to the left and so compressing the spring |32 that it will be forced into the position |32'. 'I'his will bring the contacts |40 and |4| together. So long as there is adequate water pressure in the water supply line the contacts |40 and |4| will be held together thereby, but, when the water pressure fails, the compression spring |36 will force the plunger |35 to the right, as viewed in Fig. 13, and break the circuit by forcing the spring carrying contact |40- from the position |32' to the position |32. As will be later explained, this contact may also be broken when the steam pressure exceeds a certain predetermined amount.

The switch |59 (see Figs. 1, 7 and 22)- is normally closed. This switch is closed manually but is designed, as will be later explained, to open automatically under certain conditions. Switch ..|8| is a manually operated main switch, and

switch |82 is a thermostatic switch for automatically opening the circuit when the water or building being heated has attained the desired temperature.

By reference to Fig. 22 it will be apparent that when the contacts |40 and |4| are brought together and the switches |59, |8| and |82 are closed a circuit will be established from the power lines |60 and |6| through the

carbon electrodes

38 and 46 in the steam generator, the current passing from one electrode to the other through the water in the generator. This passage'of current between the electrodes will rapidly heat the water in the generator and steam pressure will be built'up therein.

At the start of operations it is to be understood that water has been admitted to the steam generator and stands therein at about the level of the top of the electrode 45. The water level of the generator is indicated by the .water level in the glass |52. Toadmit water to the generator in the first instance it is necessary manuallyto push or pull the rod 95 to the left, as viewed inl Fig. 4, until the slide valve 33 has moved a suillcient distance to release the needle valve 8 from its seat. Water will then flow into the steam generator and when it reaches thel proper level the rod 95 is released and the slide valve automatically shuts oil.' the iniow of water. In order that the expansion chamber may be purged of air, the plug 94 at the top of the expansion chamber is unscrewed and the steam generator energized to create pressure sumcient to force water into the expansion chamber and expel the air which would otherwise be entrapped in the top of the expansion chamber. When the water level has reached the desired height, the plug 94' is, of course, replaced.

As the steam pressure builds up in the generator, the Water level in the generator is lowered because the steam pressure will force the water into the expansion chamber and compress the bellows 85. As the bellows 85 is compressed, the rod 95 which is associated therewith is moved to the left,. and the rod 16 which actuates the slide valve 33 follows the rod 95 as the helical spring expands.

Referring now to Figs. 1 and '1, the end |04 of rod will contact the end of the plunger |08.

and tend to force the spring |03 to the position |03' shown in the dotted lines in Fig. 1. 'I'he parts are so adjusted that the spring |03 will not snap into the position |03' until the steam pressure has reached a desired maximum of about nine or ten pounds. As the steam pressure builds up in the generator, the steam, Q15I course, issues from the nozzle 53 but the opening in the nozzle is so small that the discharge of steam therethrough does not prevent the building up of the desired pressure.

Steam issuing from the nozzle 53 would ordinarily tend to aspirate oil from its static level in the pipe 'I3 but due to the fact that the pipe 14 communicates with the atmosphere (see Fig. 15) no oil is drawn up to the nozzle until the spring |03 snaps into the position |03', thus causing the rubber cup to close the opening 3 through which the pipe 14 communicates with the atmosphere. When the spring |03 snaps into the position |03', the rubber cup seals the opening |n|3 and oil is immediately aspirated and projected from the nozzle with the steam. Before the fuel is projected from the nozzle, it isextremely dev sirable that the fuel igniting means be put in operation in order to avoid any accumulation of -former and an explosive gases or vapors in the combustion chamber. This is accomplished as follows.

Cooperating with the contact |61 is a contact |15 carried by a bimetallic element |16, forming a switch of the general type shown in perspective in Fig. 5. Surrounding the bimetallic element |16 is a resistance coil |11 (see Fig. 22) one end of which is connected to contact |15 and the other end of which is connected to one terminal of the primary coil |18 of a transformer |19. The secondary of the transformer is connected to the spark points |51 and |56. The bimetallic element |16 is rigidly secured at one end to a post (see Figs. 1, 5 and '1). Engaging the free end |83 of the element |16 is a frame |84 of resilient wire. The opposite end of the frame |84 is adjustably secured to a post |85 by means of screw |86 passing through post |85 and engaging nut |81 secured to spring frame |84. The screw |86 i-s so adjustedthat the spring frame compresses the bimetallic element longitudinally to the extent that the element is stressed and slightly bowed, as shown in Figs. 1, 5 and '1, it being understood that the portion of the bimetallic lelement having the highest coemcient of expansion is on the concave side of the element as shown in Figs. 1 and '1.

The parts are so adjusted that contacts |61 and |15 engage before spring |03 snaps to the position |03' which starts the fuel flowing from the nozzle. The engagement of these contacts closes the circuit through the primary of the transarc or stream of sparks is already passing between the contacts |51 and |58 before the fuel is projected from the nozzle.

It will` be observed from Fig. 22 that this circuit through the primary of the transformer includes the electrical resistance heating coil surrounding bimetallic element |16 which begins to heat the element and cause stresses therein tending to .reverse its curvature. After a predetermined interval of spark operation the stresses developed in the bimetallic element |16 become sufficient to cause it to reverse its curvature and snap from its position against stop |88 (see Figs. 1 and '1) to a postion against stop |89, thus breaking the ignition circuit.

lss of the crankl is similar to the switch sho-wn in Fig. 5. That is to say, the bimetallic element |96 is rigidly secured at one end to a post |91. The free end of the element |96 is engaged by the spring frame |84', the rear end of which is secured to post |85' by means of adjusting screw |86', which passes through the post |65 and engages nut |81 on the frame. The other end of the electrical resistance heating element is connected to contact |98 which cooperates with a fixed contact |99 electrically connected to contact 14|.

Referring particularly to Fig. 2, 200 represents the fire pot or combustion chamber into which the flame from the nozzle is projected. Stretched across this chamber and in a position where it will be heated by the combustion of the fuel is a wire 20| one end of which is anchored to a suitable abutment 202 and the other end of which is adjustably anchored, as at 203, to an arm 204 pivoted at 205 to an abutment 206 on the outside of the combustion chamber opposite the abutment 202. The arm 204 is normally urged to the left, as viewed in Fig. 2, by a tension spring 201. The lower end of the arm 204 is bent inwardly at right anglesv toward the spring element |9| which carries contact |90, and is bifurcated as shown at 208. Pivotally mounted at 209 in the bifurcation is a cam or wedge 2|0 which is urged towardand into contact with the fiat spring |9| by a spring 2|I. The face 2|2 of the cam 2|0 which contacts the flat spring |9| is curved to a fairly large radius and is designed to function as a space filler between the spring |9| and the inturned end of the arm 204.

When the burner is ignited, the wire 20| will be heated and expand. This expansion will permit the spring thus permit the spring |9| to move contact |90 away from the approaching contact |69. As long as the fuel continues to burn wire 20| remains expanded and contact |69 never reaches contact |90. On the other hand, should the burner become extinguished for any reason or should it fail to ignite from the spark, it will be evident that in the first contingency wire'20l will immediately cool and in the second contingency it will never have been heated.

Assuming that the fuel has failed to ignite, contact |90 will remain in the position shown in Fig. 1 and the parts are so adjusted that within a few seconds after the ignition circuit is closed through contacts |61 and |15 the Contact |69 will engage contact |90 thus closing a. circuit through the electrical resistance heating element |95 on the switch |59. The heat developed by this element surrounding the bimetallic element |96 will create stress in element |96 tendingto cause it to change its direction of curvature. When the stress has reached a certain magnitude, the bimetallic element |96 will instantly change its curvature and switch |59 will snap over against.

the stop 2|3 and separate contacts |98 and |99 thus breaking the circuit through the steam generator.

When the steam generator is shut oif, of course, the steam pressure falls. The bellows 65 then expands under the influence of the spring 99 and retracts rod to the right, as viewed in Fig. 7.

This movement of the rod 95 also moves the arm |69 of the bell crank |64, and insulating button |10 is brought into contact with the U-shaped metal strip 2|5 associated with the spring frame |94. This will gradually force the spring frame from its position against the stop post |99 over to the position against the stop post |98`as shown in Figs. 1 and 7. 'I'hus the ignition switch is reset automatically for operation.

If for any reason the steam pressure in the generator should become excessive due to a plugged nome or to any other cause, the circuit through the generator will be broken as follows:

As the steam pressure increases, rod 95 is pushed further and further to the left as viewed in Fig. 'l andthe nut I I9 on the end of the plunger |05 may be adjusted to contact with the arm I9 of the lever ||1 at any desired steam pressure. When the adjusting nut ||9 contacts the'arm ||0 it will push the arm to the left as viewed in Fia. 7. This will move the arm |20 of the lever to the right against the compression of spring |2i. As the arm |20 moves to the right, plunger |95 will be urged to the'right by the compression of spring |96 and this will force the spring carrying contact |40 from the position |92' to the position |92, as shown in Fig. 13, thus breaking the circuit through the generator.

In Fig. 6 I have shown a modiiled form of manually-closed-automatically-opened switch which may be substituted for switch |59. Here, the bimetcmc element ian is secured in slightly bowed position between a fixed abutment 90| and a yielding abutment 902 comprising the plunger 909, -compression spring 904 and adjusting screw 905. An electrical resistance heating element 9 06 surrounds the bimetallic element' and functions exactly as the element |95 in switch |59. A contact 901 similar to contact |98 is carried by element 900 and cooperates with a fixed contact 909. It is understood that the metal having the highest coefficient of expansion is on the concave side of the bimetallic element when cool and as shown in Fig. 6. When the bimetallic element is heated it snaps to the position 990' and is manually reset by button l909.

-From the foregoing it will be apparent that every possible contingency in the operation of my burner has been provided for. For example, if the water pressure in the supply main fails or falls to such an extent that additional water cannot be supplied to the steam generator, contacts |40 and |4 will automatically separate thus opening the circuit through the steam generator. Should the steam pressure in the generator become excessive for any reason, contacts |40 and |4| will be automatically separated and break the circuit through the generator. If the fuel fails to ignite,` the circuit through the generator will be automatically broken after a short interval. If the burner is operating and becomes extinguished If the igni- Ition spark should fail, of course the fuel will not for any reason. the circuit will also be automatically broken through the steam generator.

Whenever the switch |59- is opened it must be closed by hand. This I consider a rather important feature because it provides an opportunity for the dissipation of any explosive mixture in the combustion chamber in the time which must elapse before the device can be put into operation. thus eliminating all danger of explosion.

'I'he electrical connections for my burner will be apparent from a consideration of the wiring diagram shown in Fig. 22. In setting up the device, the primary |19 of the transformer |19 is connected to the binding posts P and P' shown in Figs. 1 and 7, and the terminal 49 for electrode 46 is connected to the binding post K on switch |59. One of the main lines |60 is illustrated as grounded according to the usual practice in A. C. installations, it being understood, however, that in practice a grounded conductor forms the return leg of the circuit. 'I'he live leg of the supply is connected to binding post P.

While my device will operate either on direct or alternating current. it is preferable to employ alternating current wherever possible in view of the fact that electrical contacts may be made and broken with less erosion to the contacting parts While I have described my invention in its preferred embodiment, it is to be understood that the words which I have used are words of description rather than of limitation and that changes within the purview of the appended claims may be made without departing from the true. scope and spirit. of my invention in its broader aspects.

What I claim is:

1. In a. device cf the character described 1nliquid fuel thereto and a steam generator for supplying fuel atomizing steam for said burner. the combination with electrical means for igniting the fuel at the burner, a switch, and an electric circuit including said igniting means and switch. of means operable in response to steam pressure in said generator for closing said switch whereby said igniting means is energized.

2. In a device of the character described including a liquid fuel burner, means for supplying liquid fuel thereto and a steam generator for supplying fuel atomizing steam to said burner, the combination with electrical means for igniting the fuel at the burner, a switch. and an electric circuit including said igniting means and said switch. of means operable in response to steam pressure in said generator for closing said switch whereby said igniting means is energized'and a thermostatic switch for opening said circuit lafter a predetermined time interval.

3. In a device of the character described including a liquid fuel burner, means for supplying liquid fuel thereto and a steam generator for supplying fuel atomizing steam to said burner, the combination with electrical means for igniting the fuel at the burner, a switch. and an electric circuit including said igniting means and switch, of means operable in response to steam pressure in said generator for closing said switch whereby said igniting means is energized and a thermostatic switch actuated by heat generated by the current in said circuit for opening said circuit after a predetermined time interval.

cluding a liquid fuel burner, means for supplying 4. In a device of the character described including a liquid fuel burner. means for supplying liquid fuel thereto and a steam generator for sup- `tact upon an extinguishing of electric circuit including electrical means for heating the water in said generator, electrical means for igniting the fuel at the burner, a first switch and a second switch, means operable in response to steam pressure of a predetermined magnitude in said generator for closing said first and second switches in predeterminatelytimed order, a first thermostatic switch having a heating coil controlled by said rst switch and operable to open the circuit to said igniting means after a predetermined time interval of operation thereof, and a second thermostatic switch having a heating coil controlled by said second switch and operable to open the circuit to said heating means upon a failure of the fuel to ignite.

5. In a device of the character described including a liquid fuel burner, means for supplying liquid fuel thereto and a steam generator for supiplying fuel atomizing steam to said burner, electrical means for heating the water in said generator, a first electric circuit including said heating means and a switch adapted normally to close said circuit, a second electric circuit including means for effecting an actuating movement of said normally closed switch to open the same and break the normally open switch in said second circuit comprising two movable contacts, means operable by the steam pressure in said generator for'moving one of said contacts toward the other with increasing steam pressure and in the opposite direc'- tion with a decreasing steam pressure, and means for automatically moving the secondcontact away from the first contact upon ignition of the burner and toward and into contact with said first conthe flame to close said second circuit and thereby break the circuit vthrough said heating means.

6. In a device of the character described including a liquid fuel burner, means for supplying liquid fuel thereto and a steam generator-for supplying fuel atomizing steam to said burner, electrical heating means for heating the water in said generator, an electric circuit'including said heating means, an element exposed to heat from said burner and adapted to expand when heated and contract when cooled, and means actuated by the contraction of said element for breaking said circuit.

'7. In a device of the character described including a liquid fuel burner, means for supplying liquid fuel thereto and a steam generator for supplying fuel atomizing steam to said burner, electrical means for heating the water in said generator, an electric circuit .including said means, a switch for opening and closing said circuit, a first movable element for effecting a circuit opening movement of said switch,` a second lelement exposed to heat from said burner and adapted to expand when heated and contract when cooled, and means operatively associated with said elements permitting an expansion movement of the second element independent of movement of the first element but effecting a simultaneous movement of both elements upon a contraction of the second element.

8. In a device of the character described including a liquid fuel burner, means for supplying liquid fuel thereto and a steam generator for supplying fuel atomizlng steam to said burner, electrical fuel-igniting means, electrical means for heating the water in said generator, an electrical circuit including said heating means and ignition means, a rst switch normally closing the circuit through the heating means and comprising a bicircuit through the heating means, a'

metallic arm and a heating element, a normally open, second switch for connecting said heating element in circuit whereby to open said first switch, and means responsive to steam pressure within said generator and heat responsive means operable in response to heat generated by said burner for closing said second switch whereby in the event of failure of fuel ignition said rst switch is opened.

9. In a device of the character described` includinga liquid fuel burner, means for supplying liquid fuel thereto and a steam generator for supplying fuel atomizing steam to said burner, electrical ignition means for the fuel, an electric circuit including said ignition means, means for heating the water in said generator, electrical timing means operable after a predetermined period of operation of the'ignition means for terminating the operation of said ignition means, h eat responsive means operable in response to heat generated by said burner, means responsive to steam pressure, within said generator and a switch controlled by said two last mentioned means for controlling the operation of said water heating means.

10. In a device of the character described including a liquid fuel burner, means for supplying liquid fuel thereto and a steam generator for supplying fuel atomizing steam to said burner, means for supplying water to said generator, an electric circuit including electrical means for heating the water in said generator, a first -switch for controlling the operation of said heating means, electric fuel-igniting meansa second switch for controlling the operation thereof, means disposedin said water supply means and responsive to water pressure therein adapted normally to maintain said first switch closed but operable upon a predetermined drop in water pressure to open the same, and means responsive to steam pressure in said generator for closing said second switch and operable in response to a predetermined, relatively high steam pressure to open said rst switch.

11. In a control system for liquid fuel burners including means for supplying liquid fuel thereto and a steam generator for supplying fuel atomizing steam to said burner, an electric circuit including a thermostat, electric ignition means, a switch including means operable in response to steam pressure within said generator for closing the circuit through said ignition means, electrical timing means in circuit with said ignition means for opening said switch after a predetermined time interval of operation of said. ignition means, electrical water heatingmeans for said generator, a normally closed switch in series with said water heating means, electrical timing means adapted to open said last mentioned switch and heat responsive means operable inresponse to heat generated by said burner adapted to connect said last mentioned timing means in circuit when combustion fails to take place in the burner; said pressure responsive means being operable to close said first mentioned switch whereby said ignition means is energized and thereafter to connect said last mentioned electrical timing means in circuit whereby the circuit -through said last mentioned switch is opened; and said heat responsive means being disposed within range of the heat generated by said burner to prevent closingof said last mentioned switch by said pressure responsive means while combustion occurs. 12. In a device of the cluding a liquid fuel burner, means character described infor supplying plying fuel atomizing steam to said burner, electrical means for heating the water in said generator, means for igniting said fuel at the burner, an electric circuit including said igniting means and a switch, means operable in response to steam pressure in said generator i'or closing said switch. said switch including a thermostatic element operable by heat generated by the current in said circuit for opening the vsame after' a `predetermined time interval. and said circuit including in 2,199,986 liquid fuel thereto and a steam generator for sup? series the water heating means and a thermostatic switch having a heating coil, heat responsive means disposed to be affected by heat i'rom the burner. and a switch controlled by said steam pressure-responsive means and by said heat responsive means for closing a circuit through said heating coil whereby said circuit is opened by said thermostatic switch in the event of failure ot fuel ignition.

WILLIAM C. MASON.