US2781087A - Fuel oil conditioning system - Google Patents

Description

P. sToRTl ETAL' 2,781,087 FUEL on. CONDITIONING SYSTEM Feb. 12,' 1957 Filed sept. 17, 195s 2 Sheets-Sheet 1 Peb. 12, 1957 FUEL oir. CONDITIONING SYSTEM Filed Sept. 17. 1953 2 sheets-sheet 2 P. sToR-rl E'rAl.v 2,781,087'

United States Patent C 2,781,037 FUEL oIL coNDmoNING SYSTEM Peter Storti, Lakewood, and Ernest C. Webb, yBay Village,

Dhio, assignors to lron Fireman Manufacturing Company, Portland, Oreg.

Application September 17, 1953? 'Serial No. 380,816 V6 Claims. (Cl, 15S-H36) atomizing nozzle. For illustration of a type of burner to which our fuel oil conditioning system isA adapted reference is here made to U. Sc. Patent No. 2,591,533 issued to W. l. J. Fritz on April l, 1952.l

it is well known to practitioners in this art that heavy fuel oil which is an economical fuel for industrial use 1s not necessarily of uni-form physical characteristics between loads as supplied to the user and that its viscosity and other handling atecting characteristics vary greatly with temperature. ylt is also well known not only that such oil must-be up to a speciliedrtemper-ature for satisfactory atomiza-tion by the rotary cup method but that an excessive temperature will cause trouble by fractional distillation in which the lighter con'iponents tend to vaporizc andthe heavy fractions will tend to. sludge.

Since these burners are generally provided for the supply of large heating requirements and use large amounts of fuel the fuel storage is usually remote from the burner and often at a lower elevation. A positive displacement pump is therefore apart of the burner andis used to draw the fuel from storage to the burner. Fromthe discharge end of this pump the oil must heV delivered' toI the rotary cup atomizer in `the required quantity. which varies with the need 'for heat. The rotary cup'atomizer is V-belt driven by the burner motor which. drives the primary air fan and the oil pumps of the burner. Different burner makers use different mechanisms to accomplish this continuous supply of oil to thenozzleas required.A The above noted Fritz patent showsr one of the more. successful methods for this accomplishment. As noted inthat patent ythe burner here illustrated ils'provided with av reservoir to whichV the positive displacement pump delivers theoil as it is drawn from storage and" from which a variable stroke piston pump picks u'p the oil in quantities proportioned to the need for hea-t and delivers the oil from the reservoir to the nozzle through a 'nozzle' line. TheV Fritz patent shows a very satisfactoryand unique arrangement in which both the positive displacementfpump and the piston pump are both submerged'in the oiljreservoir.

Since the positive displacement pump brings more oil than is needed' from temporarystorage` tothe reservoir at the burner the reservoir is` providedffwith an outlet through which the excess oil is returnedlto storage. This arrangement in practice is varied in4 manyliways. One variation is to pass the return oil through a heat exchanger on its way back to storage wherein the heating oil is returned near the. inlet to the suction line from the storage tothe positive clisplacementpump` in -thereservoir and in this way provide `some-. temperature 'conditioning of the oil. However, additional` temperature condition` ing of theoil isalwaystrequiredjat the burner.

Beforeour present invention thecommon practicewwas to provide a thermostatic'ally;controlledelectric-heaterin.

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the nozzle line. This electric heater necessarily was small in volume and could-contain only a very limited amount of oil at one time so that on high tire the passage of oil through the heater 'was rapid thus necessitating a rather high supply of electric heat. Then at lower firing rates the heater thermostat operating between set temperature limits supplied heat Vat too great a rate, when on, thus tending to vaporize and sludge the oil and could cause the oil llame to puff or vibrate or cause other unsatisfactory operation. The oil at the nozzle often varies as much as thirty degrees in temperature with this type of operation. And this condition could be oa'dly aggravated under standby conditions.

' It is therefore a primary object of our invention to provide an industrial oil burner with means for supplying the nozzle with oil properly conditioned for burning at all times.

It is a second object to provide means for supplying theV nozzle at all times with oil which is lfree of entrained vapors or gases and which is maintained Within relatively narrow preset temperature limits.

lt is a third object to provide means for heating the oil in the reservoir at the tourner to a required temperature before the oil is injected into the nozzle line to the burner.

lt is a fourth object to provide means in the reservoir for directing the thermal circulation of the oil heated by an electric heater therein so that no part of the oil will rem-ain long enough in contact with the heater to be ovcrheated.

It is a fth object to provide means for thermally ciroulating the oil in the reservoir in a manner to allow the entrained air and oil vapors to escape to the surface and to purge the air and oil vapors to the outside of the reservoir.

llt is a sixth object to provide means lfor proportioning the oil pumped from storage to the reservoir, some to be circulated through the reservoir where it is conditioned and delivered to the nozzle line and the rest to be returned from the reservoir to storage.

It is a seventh object to provide an oil burner with a temperature controlled oil reservoir having a sufliciently heat conducting connection with the frame of the burner surrounding the nozzle line so that the nozzle line will he warm at all times and the burner will be ready on a call for heat to immediately supply the nozzle with conditioned oil.

How these and other objects are attained is explained in the following description of preferred form of our invention referring to the attached drawings, in which Fig. l is a fragmentary front view in partial section of an industrial oil burner of the type shown in U. S, Patent No. 2,591,533 but with the oil conditioning means of our invention.

Fig. 2 is a schematic side sectional View of the oil conditioning means'of our invention showing one scheme of oil circulation therethrough.

Fig. 3 is a schematic side sectional view of the oil conditioning means of our invention showing another scheme of oil circulation therethrough.

Like numerals of reference refer to like parts in the several figures of the drawing.

Referring now to the drawings, looking at the burner from the side of the burner away/from the furnace Wall through which the fuel discharge end of the burner is inserted to which the burner is attached, in Figure l a partial front elevation in partial section ofthe main frame of the yburner is `shown at 11 `on which is secured stationary hollow hub lZwhich in turn is'securedV to and carries oil reservoir 13 made up oil tight of end plates i4, l5 and two presscdisteelhalvesl and 17.

The hollow main sli-aft of. the burner indicated at'lS with worm 19 formed thereon isdriven at itsrfront end .3 by an electric motor through a V-belt drive, not shown, and at its furnace end carries the fuel oil atomizing cup 35, shown schematically in Figures 2 and 3. For further details of the burner construction, see the Fritz patent above noted. Stationary nozzle line adapted to conduct the fuel oil from the reservoir 13 to the a'tomizing cup 35 enters the hollow rotating main shaft 18 at 21 and extends forwardly Within but not touching the shaft.

Worm 19 meshes with and diives worm gear 22 secured to and driving pump shaft 23 which drives both a positive displacement gear pump 29 and a variable stroke piston pump 34 submerged in reservoir 13. Shaft 24 journalled in end plate 15 is adapted t-o be rotated to vary the stroke of the piston pump adapted to supply oil to the nozzle through line 20.

The oil path from the remote point of storage to the nozzle is shown schematically in Fig. 2. As there indicated by the arrows, oil from the storage location through suction line 25 enters the lower chamber 26 of burner carrying hinge post 27 and from chamber 26 is conducted through pipe 28 to the suction side of the positive displacement gear pump 29 in reservoir 13. Pump 29 delivers oil to bendable copper tube 30 whose outlet end loosely enters conduit 31 connecting reservoir 13 with upper chamber 32 of hinge post 27. Excess oil return line 33 connects chamber 32 with the remote oil storage means. l

Oil being discharged `from tube into conduit 31 will leak back around the outside of pipe 30 into reservoir 13 in suicient quantity to keep reservoir k13 full.

Variable stroke piston pump 34 picks up oil from reservoir 13 and delivers it through nozzle line 20 to the atomizing cup shown schematically at 35.

Electrically energized oil heater 36 is removably secured into reservoir 13 with the terminal board and l thermostat within the cover 37 outside the reservoir and the heating elements 38 within the reservoir.

Oil directing baie 39 open at the bottom and both ends and with its top sloping upwardly towards the front of the burner has the eiect of causing the oil as it is heated by the electric heating elements to move towards the front of the reservoir and to move upward between the reservoir wall and vertical bale 40 reaching substantially from side to side of the reservoir. Baffie 41 also extending from side to side of reservoir 13 is spaced from the top of the reservoir to leave a gap 42 for air, vapor or froth to pass from the top of the hot oil to outlet conduit 31. Baflies 40 and 41 are also spaced at 43 for entrance of hot oil into the central space inside baffles 39, 40 and 41, from which space pump 34 picks up hot Oil to deliver to the nozzle. New oil from pipe 30 spills back into reservoir 13 from conduit 31 in the amount necessary to make up for the oil delivered to the nozzle and this new oil is directed downward back of baffle 41 to the low end of baille 39 to pass around the heating elements 38.

With the arrangement described it is seen that the reservoir will always be substantially full of continuously circulating oil conditioned to a pre-set temperature and that means are provided for continuously relieving the oil of air or vapor and for passing the air or vapor back to the return line to the storage location. Also it is seen that oil is being continuously circulated by pump 29 from storage to reservoir 13 and back to storage and while the reservoir is kept full of hot oil at all times only the oil which is required for burning is heated.

It should be noted that even though the burner should be idle but desired to be on standby condition ready for use, it will always have immediately available a supply of conditioned oil and that due to the intimate thermal connection of reservoir 13 with the main frame 11 of the burner through heavy end plate 14 and hub 12 the main frame llwill be warm at all times and therefore the nozzle'line 20 andthe oil therein will remain warm and the oil in good atomizing condition. This arrange- 4 ment which` provides fully conditioned oil for starting has been found to eliminate the erratic starting conditions previously prevalent in large heavy oil burners and thus to make for safer, cleaner and more efficient operation.

Again with free circulation of a relatively large quantity of Oil around the heater and the larger heat storage capacity of the larger amount of oil surrounding the heater it has been found that the temperature over which oil is supplied to the nozzle has been reduced from a range of 20 to 30 degrees to a range of 2 to 3 degrees.

Since the electric heater used must necessarily be of capacity suicient for peak use it normally is used intermittently, and thus for only a small part of the time, to heat the oil actually requiredl for burning. In many installations therefore if the excess capacity of the electric heater could be used to somewhat raise the temperature of the oil in the suction line better operation of the system couldvbe assured. In our system this desired operation can be obtained merely by bending copper tube 30 to vary the position of the end of tube 30 in conduit 31 sufficiently to cause the desired proportions of the oil to be heated before it is returned to storage.

In large installations using the least refined and heaviest oils in colder weather the electric heater could not reasonably be expected to prepare the oil for pumping from storage. In these cases heat transfer equipment remote from theburner is provided to additionally heat the return line oil.'A This additional equipment is readily used in connection with theoil conditioning means of our invention without interfering with its nicety of operation,

as shown in Fig. 3 in which a four port hinge post 44 is used in place of the simpler post 27 shown in Fig. 2.

In Fig. 3 it is to be noted that the suction line from the remotestorage to the gear pump 29 includes the pipe 45, the outer lower chamber 46 of post 44 and pipe 47. The discharge line of pump 29 includes pipe 48, the inner upper chamber of post 44, and pipe 50 leading to the remote heater. The return line 51 from the remote heater joins the inner lower chamber 52 of post 44 which is connected through conduit 53 with the interior of reservoir 13. The return line 54 to the remote oil storage is connected with reservoir 13 through conduit 55 and the outer upper chamber 56 of post 44; in Fig. '3 the two horizontal lines across hinge post 44 just below the reference number 58 indicates that the oil passage in'hinge post 44 .above and below the two lines are separated. Conduits 53 and 55 are connected by by-pass conduit 58. Adjustable orifice 57 in conduit 55 between reservoir 13 and by-pass 58 regulates the amount of the oil from the remote heater which is additionally heated in the reservoir and returned to the remote storage. It is seen that the arrangement of Fig. 3 conditions the oil for. burning as does the previously described scheme of Fig. 2 but provides additionally for a remote heater to aidA in conditioning the oil for pumping from the remote vstorage to the burner.

From the above descriptions of our invention as prac- I ticed and shown in Figs. 2 4and 3 it is seen that they are essentially the same except that where the oil in storage is very cold or where the oil in storage is cold and the burner is of high capacity adapted for burning more oil than heater 36 can heat adequately, it is found desirable to give the oil in transit from storage to delivery into the reservoir a preheat.

This preheat is provided by any of the many closed oil heaters available for the purpose, a common one being simply a metal pipe coil submerged in the boiler water if the burner is being used for heating a boiler. Such a closed submerged heater coil would be connected between pipes 50 and 51 of Fig. 3 so that oil on its Way'from storage to be discharged into reservoir 13 would be drawn by gear pump 29 from storage through pipe 454 and discharged from pump 29 through tubes 48, 49, 50, the submerged heater, not shown, 'tubes51,f52,53, 58, and 54 back to storage. The

reservoir end of tube 53 being open, tube 50 being under pressure from pump 29 and heater 36 causing a constant thermal circulation or oil in the reservoir as shown by the arrows, oil will continuously spill from tube 53 into reservoir 13, flow downwardly between baille 41 and tbc right hand side of reservoir 13, circulate to the left and upwardly around heaters 38 under baille 39, upwardly to the left of baffle 40, to the right and downwardly over the upper end of baille 40 in sullicient quantity for pump 34 to supply rotary cup 35 through tube 20 with the oil required by the burner. The oil circulating in the reservoir over the heaters 38 will give up its entrained air and oil vapor as it travels upwardly to the left of baffle 40 and the air and vapor will collect within the top of the reservoir where it will gradually pass to the right through gap 42 over the upper end of baille 41 and through gap S7 and tube 55 to the interior 56 of the upper end of hinge post 44 and thence to the remote oil storage through pipe 54. Oil incoming from the external oil heater through tube 51 and tube 53 but not spilled into reservoir 13 from the inner end of tube 53 will be by-passed through tube 58 to tube 55 and thence to tube 54 through upper end 56 of post 44. Since all of the reservoir and piping except tubes 45, 47 and the lower end 46 of post 44 is under pressure from pump 29, reservoir 13 is substantially lllled with oil at all times except for the small variable air space at the top thereof. There is also a continuous thermal circulation of oil around the outer wall of reservoir 13 outside of balles 39, 40 and 41.

Figs. 2 and 3 being schematic are not intended to show structural details where such details would be well known to persons skilled in the art.

It is seen that disregarding the external heater for which Fig. 3 is equipped Figs. 2 and 3 are the same, the circulation of oil from the remote oil storage to the reservoir 13 being completed by the spill of oil from tube 30 at its entrance into tube 31 in Fig. 2 while in Fig. 3 the spill into reservoir 13 is from the inner end of pipe 53. In Fig. 2 the excess oil not spilled into reservoir 13 but returned to remote storage is discharged through pipes 30, 31, the upper end 32 of hinge post 27 and through pipe 33, while in Fig. 3 the excess oil not spilled into reservoir 13 from the inner end of tube 53 is bypassed through tubes 58, 55, the upper end 56 of hinge post 44 `and tube 54. In both Figs. 2 and 3 the internal heater 33 is thermostatically controlled at 37 and the heater will be energized and de-energized in response to the need for holding a preset oil temperature in reservoir 13. If it is desired to use heated oil from reservoir 13 to supply some heat to the remote oil storage the amount of oil heated in reservoir 13 and circulated to the remote storage is controlled in Figure 2 by the amount of overlap of tube 30 into tube 31 while this control in Fig. 3 is by variable orifice 57 governing the circulation of oil into reservoir 13 through tube 53 and out of reser- 6 voir 13 through orillce 57 it being understood that in the latter case due to the thermal circulation in reservoir 13 the circulation of oil is down from the inner end of tube 53 clockwise around the reservoir over the top of baille 41 and out through orifice 57.

Other arrangements of external piping can be used with our oil conditioning system for dilerent types or arrangements of external heaters, the arrangement of Fig. 3 being only typical of them.

Having thus cited some of the objects of our invention, described and illustrated a preferred form of struc-V ture for practice of our invention in connection with a typical heavy oil burner, and explained and described a variation of structure for a typical additional use, we claim:

l. An oil conditioning system for an oil burner comprising a reservoir, a circulating pump having an inlet and an outlet, a iirst conduit means connecting said inlet to a remote source of oil, a second conduit means connecting said outlet to said remote source of oil, spill means from said second conduit to said reservoir, a third conduit constituting an outlet means for conditioned oil from said reservoir, a heater in said reservoir, baille means in said reservoir adapted to direct oil from said spill means in said reservoir :downwardly over said heater to be heated thereby then upwardly to release to a space above the surface of said oil in said reservoir tthe gas entrained in said oil, and said spill means including means opening from said second conduit below the surface of said oil in said reservoir to spill oil into said reservoir and means opening from said reservoir to said second conduit above the surface of said oil to spill gas from said reservoir to said second conduit.

Z. The system of claim 1 in which both said opening means of said spill means are combined in one opening means adapted to extend both above and below said oil level in said reservoir.

3. The system of claim l including a metering pump in said third conduit outlet means.

4. The system of claim 1 in which one of the openings of said spill means is variable.

5. The system of claim 2 including oil metering means in said third conduit outlet means.

6. The system of claim 2 in which said spill opening is of variable resistance to the llow of oil therethrough.

References Cited in the le of this patent UNITED STATES PATENTS

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