US3395863A - Fuel feed arrangement for oil burners - Google Patents

Description

Aug. 6, 1968 T. L. JOHNSON FUEL FEED ARRANGEMENT FOR OIL BURNERS 2 Sheets-Sheet l Filed sept. 29, 196e Nm, .wmf Nm, /1 um ATTO R N EYS Aug. 6, 1968 T. L. JOHNSON FUEL FEED ARRANGEMENT FOR OIL BURNERS 2 Sheets-Sheet Filed Sept. 29, 1966 ATT RNEYS United States atent 3,395,863 FUEL FEED ARRANGEMENT FR OIL BURNERS Terence L. Johnson, Bridgewater, NJ., assignor to Automatic Switch Company, a corporation of New Jersey Filed Sept. 29, 1966, Ser. No. 582,999 Claims. (Cl. 239-125) ABSTRACT 0F THE DISCLOSURE Oil burner assembly includes feed conduit for conducting fuel to combustion chamber, and outer tube concentric therewith defining annular fuel recirculating passage. Valve at discharge end of feed conduit arranged to alternatively (a) allow fuel flow to combustion chamber and prevent flow to recirculating passage, or (b) allow recirculation and prevent flow to chamber. Electric actuator spaced from combustion chamber operates valve via a rod extending longitudinally through feed conduit.

This invention relates to oil burners and particularly to fuel feed arrangements for controlling the flow of liquid fuel to a boiler or other combustion apparatus.

Oil burners, particularly those of commercial or large capacity, commonly use heavy or viscous grades of fuel oil that necessarily must be pre-heated to reduce its viscosity and insure proper combustion. In known oil burners, a valve is provided to control the flow of fuel oil to a feed tube on the end of which is a discharge nozzle through which the oil is released into a combustion chamber. The valve is located upstream of the discharge nozzle away from the combustion chamber in order to keep the solenoid actuator of the valve far enough from the heat of the combustion chamber to avoid damage to the solenoid. The arrangement is such that when the lvalve is closed, a slug of oil is retained in the feed tube between the valve and the burner nozzle which is not subjected to the pre-heating step. Accordingly, when starting up the boiler, this slug of fuel oil which is unheated and cold produces combustion problems such as smoky starts, or in the alternative necessitates a relatively complex means for prevent this initial poor combustion, such as the use of extra heaters. In addition, at shutdown of a hot boiler, the slug of oil trapped between the burner nozzle and the valve is subject to overheating from the hot combustion chamber with resultant carbonizing of the oil, thereby requiring frequent cleaning to prevent clogging of nozzle orifices or other malfunction.

Accordingly, an object of the present invention is to provide a burner assembly which is operable to prevent smoky starts and which tends to prevent overheating and resulting carbonization of the fuel oil upon shut down.

Another object of the invention is to provide a feed arrangement for controlling the flow of liquid fuel to a combustion chamber wherein virtually no fuel remains uncirculated in the feed tube upon shut down of the burner.

A further object is to provide a simple and economical burner assembly in which the frequency of cleaning to prevent clogging of nozzle orifices or other malfunctioning is kept at a minimum.

A further object is to provide certain improvements in the form, construction and arrangement of the several elements of the assembly whereby the above-named and other objects may effectively be attained.

The aforesaid objects of the present invention, and other objects which will become apparent as the description proceeds are achieved, and the aforesaid disadvantages of prior art devices are overcome, by providing an arrangement including a valve means which effects a closing olf of the fuel oil flow at a location adjacent to the 3,395,863 Patented Aug. 6, 1968 ice discharge nozzle, and means for conducting recirculating fuel oil up to the point of valve closure, thereby eliminating a slug of cold oil at start-up and preventing overheating of any fuel at shut-down of a hot boiler. Furthermore although the valve is located close to the discharge nozzle and hence the combustion chamber, the solenoid actuator of the valve remains at a safe distance from the combustion chamber. With this arrangement the burner assembly nozzles may be positioned at locations most desirable for eflicient combustion without encountering the problems attendant the aforesaid known prior art devices.

For a more detailed description of the present invention, reference will now be made to the accompanying drawings, wherein:

FIG. 1 is an elevational view, parts of which are broken away and shown in section, of a burner assembly constructed according to the invention;

FIG. 2 is a sectional view taken along'line 2 2 of FIG. 1', and

FIG. 3 is a fragmentary elevational view, parts of which are broken away and in section, of an alternative embodiment of the invention.

Referring to the drawings, FIG. 1 shows a burner body 10 having an inlet connection 12 which is adapted to receive fuel oil from a storage facility (not shown) through a supply conduit 16. Before the fuel oil reaches the inlet 12, it passes through a heater 14, which may be an electric heater, the heater and supply conduit being shown schematically. Also shown schematically is a recirculation circuit 18 connected to the supply conduit 16 at a point upstream with respect to the heater 14. The burner body 10 is coupled to a connector piece 20 by -means of a retaining ring 22, the ring 22 being internally threaded at one end to cooperate with the external threads on the body 10, and having an inwardly directed flange at its other end engaging the outwardly projecting flange on the connector 20. A spacer 24 along with the flange 26 of a sleeve 28 are disposed between the end of the connector piece 20 and a shoulder on the burner body 10. The flange 26 serves as a sealing gasket to effect a liquid tight seal. The connector piece 20 is threadably connected to a by-pass body 30, a gasket 32, e.g. an O-ring of rubber or other resilient material, effecting a liquid-tight seal therebetween.

The by-pass body 30 which has a recirculating connection 34 leading to the recirculating line 18, threadably receives an outer tube 36, a gasket 37, which may be made of copper, effecting a yliquid-tight seal therebetween. A mounting bracket 35 encircling at least part of the outer tube 36, and/ or a mounting ring 39 threaded on the outer tube 36, may be provided to support the burner assembly on a boiler or other combustion chamber (not shown).

Threaded into the end of the outer tube 36 is an end plug or adapter 38 which has an external and an internal thread 40 and 42, respectively, adapted to accept either one of the two general types of standard oil burner nozzles on the market. In the illustrated embodiment, the inner thread 42 is shown receiving a nozzle 43. A gasket 44, which may be made of copper, effects a liquid tight seal between the outer tube 36 and the adapter 38.

The adapter 38 has an internal shoulder 46 which receives a member 48 (hereinafter, sometimes referred to as a valve seat) having an external flange 50 against which the end of an inner tube or conduit 52 abuts. The flange 50 is thereby sandwiched between the discharge end of the inner conduit 52 and the inner end of adapter 38. The tube 52 extends rearwardly and terminates within the connector piece 20 previously described, whereby the burner body 10, connector 20, and inner tube 52 define a feed conduit for the fuel oil. A biasing means in the form of a spring 54 seats at one end against an inwardly projecting shoulder S6 of the connector piece 20, and the other end abuts the end of inner tube 52 to urge the latter toward the left in FIG. 1, whereby the inner tube is urged against the flange 50 of valve seat 48 and the latter, in turn, is urged against the adapter 38. The inner and outer tubes 52 and 36 respectively, are radially spaced from each other to form an annular recirculating passage S8 therebetween, the function of which will be described hereinafter. At this point it will be apparent, however, that the internal passage in inner tube 52 is isolated from the annular recirculating passage 58 by the previously described valve seat 48 and end plug 38 at its forward end, and on the rear end, by the gasket 32. This gasket, in addition to effecting a liquid tight seal between the connector piece and by-pass body 30, as previously described, also seals against the outer surface of inner tube 52. It will be appreciated that by virtue of the fact that the inner tube 52 terminates short of the shoulder 56 and the employment of a spring 54 to span the gap between the end of the tube 52 and the shoulder 56, the adapter 38 may be threaded into outer tube 36 as tightly as necessary to effect a good compression seal on gasket 44 without danger of interference as a result of the engagement of the adapter 38 with the tube 52 via flange 50. The spring 54 simply yields as much as required to permit the entry of adapter 38 into the tube 36. At the same time, the spring S4 insures that the discharge end of inner tube 52 will be pressed tightly against the flange 50 of valve seat 48.

Mounted within the inner tube 52 is a longitudinally extending rod 60, the forward end of which carries a valve member 64 fastened to the rod by means of a pin 62 which passes through aligned holes in the rod and valve member. The pin 62 may be held in place by suitable retaining means such as a coil spring 66. The valve member 64 has a cylindrical portion 67 and a conical plug portion 68 functioning as a spool valve and a poppet valve, respectively. The valve member 64 is arranged for sliding movement in the inner tube `52, the latter serving as a guide for the valve member as it slides between its open and closed positions. The conical plug 68 is adapted to engage the valve seat 48 to effect a closure. A plurality of longitudinal passages 70 (FIGS. 1 and 2) are provided in the cylindrical spool portion 67 so that when the conical plug 68 is unseated, fuel oil may flow from the inner tube 52 through the passages 70l and the central passage in the valve seat 48, and out through the nozzle 43.

The actuating rod 60 is threadably secured at 73 to a rod connector 72 and locked in place by the lock nut 74, the threads 73 facilitating adjustment of the effective length of the combined actuating rod 60 and rod connector 72. A transverse pin 76 on the end portion of rod connector 72 pivotally receives one arm of a bell crank lever 78 which is pivotally mounted on the burner body 10 by the pin 80. The other ann of the lever 78 is actuated by a solenoid 82, the latter being mounted on the burner body 10 and having a slidable armature 84 which is urged downwardly in FIG. 1 by biasing means in the form of coil spring 86. The lower end of armature 84 has an opening 88 adapted to receive a rounded end portion 90 on lever 78. It will be apparent that up and down movement of solenoid armature 84 will effect rocking movement of crank lever 78 about pivot pin 80, which in turn will effect back and forth movement of actuating rod 60 to seat and unseat the conical plug 68.

Although, as previously described, the interior of inner tube 52 is isolated from the annular recirculating passage 58 at the ends thereof, one or more by-pass ports 92 (FIGS. l and 2) are provided in the inner tube 52 to establish communication between the interior of inner tube 52 and the annular recirculating passage 58. It will be apparent from the drawings that the aforesaid bypass communication is established when the conical plug 68 is seated, as in FIG, 1, and that the by-pass ports 92 are obturated by the cylindrical spool portion 67 of valve disc 64 when the latter is moved to the right to unseat the conical plug 68.

In operation, with the burner shut down, the solenoid coil 82 will be de-energized and the spring 86 will urge the solenoid armature 84 downwardly. This action serves to seat the conical plug 68 against valve seat 48 to prevent flow of fuel oil to the discharge nozzle 43. Under the influence of a pump (not shown) fuel oil will ow from the inlet connection 12, into the inner tube 52, through the by-pass ports 92, into the annular recirculating passage 58, and into the lay-'pass body 30 from which it is moved through the recirculating line 18 back to the inlet connection 12 after having passed through the heater 14. With the burner operating, the solenoid coil 82 is energized to move the solenoid armature 84 upwardly against the bias of spring 86 to effect unseating of valve plug 68 and covering of by-pass ports 92 and the cylindrical spo'ol portion 67 of valve member 64, thus allowing flow of fuel oil past the valve seat 48 to the nozzle 43 while shutting off tlow through the by-pass ports 92.

In the above described burner assembly, it will 'be observed that the solenoid coil 82, located in a position spaced from the discharge nozzle 43, is not exposed or subjected to the high temperatures of the combustion chamber into which the nozzle 431 discharges the fuel oil. Also when the fuel to the discharge nozzle 43 is cut off by the seated valve plug 68, a continuous ow of oil may be recirculated in the inner tube 52 up to the valve disc `64 adjacent the discharge nozzle 43. This recirculated oil may be kept warm by the heater 14 so that there will be no slug of cold, viscous oil in the burner assembly upon start-up. Further, on burner shutdown, the recirculating oil precludes the establishment of a stagnant slug of oil in the burner assembly. Since such a slug would tend to become overheated by the hot combustion chamber with resultant carbonization of the fuel, the problems resulting from such carbonization are eliminated in the illustrated burner assembly, thereby preventing resultant malfunctioning and decreasing the frequency of maintenance operations.

The alternative embodiment in FIG. 3 is similar to the FIG. 1 embodiment except that the positions of the solenoid coil and inlet connection have been interchanged. Thus, in FIG. 3, the solenoid coil 82a is mounted on the end of the burner -body 10a and the inlet connection 12a is located at -a position spaced from the end of burner 4body 10a. Except for this change and the resulting change in linkage between the solenoid armature 84a and rod connector 72a, the various parts are similar to those in the FIG. l. Accordingly, except as further set forth hereinafter, it is believed that the construction, arrangement, and function of the various parts in FIG. 3 are apparent, and they will not be described in detail. Parts corresponding to those of FIG. 1 are identi-lied by the same reference numerals, but With the letter a appended.

With the solenoid coil 82a on the end of the burner body 10a, the solenoid armature 84a may have a longitudinal extension 94 secured to the rod connector 72a. The solenoid spring 86a urges the actuating rod 60a to the left to seat a closure plug just as the solenoid spring 86 urges seating of closure plug 68 in FIG. 1. It will be apparent that the advantages of the FIG. l embodiment are also applicable to the FIG. 3 embodiment.

A burner assembly according to the present invention is adapted to handle preheated fuel oil, but it may also handle light grade fuel oils. The principles of the present invention are adaptable for use on known fuel systems in which case there is eliminated the need for the following conventional equipment: a primary shut-off valve (normally closed safety valve), a by-pass shut-olf va-lve (normally open valve), and heating cable and its required associated equipment such -as thermostats, relays, and electrical connections.

The invention hereinabove described may be varied in construction within the scope of the claims, for the particular devices selected to illustrate the invention are but two of many possible embodiments of the invention. The invention, therefore, is not to be restricted to the precise details of the structures shown and described.

What is claimed is:

1. An oil burner assembly adapted to feed liquid fuel to a combustion chamber or the like, comprising a feed conduit conducting liquid fuel to a nozzle from which the fuel is discharged into said combustion chamber, means extending at least partially along said feed conduit defining a recirculating passage, a by-pass port in said feed conduit near the discharge end of the latter permitting communication -between said feed conduit and said recirculating passage, valve means having (a) an open position permitting flow of fuel from the feed conduit to the nozzle but preventing ow of fuel from the feed conduit to the recirculating passage, and (b) a closed position to preclude flow to the nozzle while permitting ow to the recirculating passage, said valve means comprising a valve member and a seat member located at the discharge end of the feed conduit, said valve member, seat member, and by-pass port being so arranged that said valve member alternatively (a) engages said seat member and opens said by-pass port, or (b) is spaced from said seat member and closes said by-pass port.

2. An oil burner assembly according to claim 1 wherein said means defining said recirculating passage comprises an outer tube encircling and extending along at least a part of said feed conduit, said outer tube having la larger inner diameter than the outer diameter of at least a portion of said feed conduit to form an annular space therebetween constituting said recirculating passage.

3. An oil burner assembly according to claim 1 wherein said valve means comprises an electric actuator, and means operatively connecting said actuator to said valve member, said connecting means extending longitudinally of said feed conduit, thereby permitting movement of said valve member with respect to said feed conduit.

4. An oil burner assembly according to claim 3 wherein said electric actuator is -a solenoid coil having an armature reciprocable along an axis generally parallel to the longitudinal axis of the feed conduit.

5. An oil burner assembly according to claim 3 wherein said connecting means comprises a rod longitudinally movable in said feed conduit.

6. An oil burner assembly according to claim 5 wherein said electric actuator is a solenoid coil having an armature reciprocable transversely of the longitudinal axis of the feed conduit, said connecting means comprising a lever operatively connecting said armature to said rod.

7. An oil burner assembly adapted to feed liquid fuel to a combustion chamber or the like, comprising a feed conduit conducting liquid fuel to a nozzle from which the fuel is discharged into said combustion chamber, means extending at least partially along said feed conduit defining a recirculating passage, valve means having an open position permitting flow of fuel from the feed conduit to the nozzle and a closed position to preclude ow to the nozzle while permitting ow to the recirculating passage, said valve means comprising a spoollike valve member slidaible with respect to said feed conduit and cooperable with a seat member located at the discharge end of the feed conduit, whereby when the valve means is in said closed position with the closure member seated, fuel in the feed conduit is recirculated via the recirculating passage, and said feed conduit having a by-pass port located adjacent to said valve member so that the side wall of said valve member covers the port when the valve means is in said open position and uncovers the port to permit recirculation from the feed conduit to the recirculation passage when the valve means is in said closed position.

8. An oil burner assembly according to claim 7 wherein said spool has one or more longitudinal passages establishin-g communication between its end faces, whereby fuel ows from said feed conduit through said longitudinal passages to the nozzle when said valve means is in its open position.

9. An oil burner assembly adapted to feed liquid fuel to a combustion chamber or the like, comprising a feed conduit conducting liquid fuel to a nozzle from which the fuel is discharged into said combustion chamber, an outer tube encircling and extending along at least a part of said feed conduit, said outer tube having a larger inner diameter than the outer diameter of at least a portion of said feed conduit to form an annular space therebetween constituting a recirculating passage, said outer tube carrying an adapter for receiving a nozzle, valve means having an open position permitting flow of fuel from the feed conduit to the nozzle and a closed position to preclude ow to the nozzle while permitting flow to the recirculating passage, said valve means comprising a valve member cooperable with a seat vmember located at the discharge end of the feed conduit, said seat member being located between said adapter and the discharge end of said feed conduit, whereby said adapter 'and seat member `serve to separate the interior of the feed conduit from the annular recirculating passage, and when the valve means is in said closed position with the closure member seated, fuel in the feed conduit is recirculated via the recirculating passage.

10. An oil burner assembly according to claim 9 wherein biasing means are provided to urge said feed conduit against said seat member and adapter, to facilitate assembly of said feed conduit, outer tube, `and adapter and insure a good sealing yContact between the discharge end of said feed conduit and said seat member.

References Cited UNITED STATES PATENTS SAMUEL F. COLEMAN, Primary Examiner.

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