US3001574A - Oil burner fuel supply system - Google Patents

Description

Sept. 26, 1961 F. l.. RUNNINGER 011. BURNER FUEL SUPPLY SYSTEM 2 Sheets-Sheet 1 Filed March 27. 1959 ATTORNEY Sept. 26, 1961 F. L. RUNNINGER OIL BURNER FUEL SUPPLY SYSTEM 2 Sheets-Sheet 2 Filed March 27, 1959 rif United States Patent Frederick L. Runninger, Parma, Ohio, assignor to Iron Fireman Manufacturing Company, a corporation of Oregon Filed Mar. 27, 1959, Ser. No. 802,534 Claims. (Cl. 15S-36.3)

This invention relates generally to a fuel oil burner of the pressure atomizing type which uses a positive pressure pump to supply to the nozzle line of the burner fuel oil in excess of the requirement of the burner and which includes Ian adjustable spring loaded valve preset to limit the pressure of oi-l in the nozzle -line by returning the excess oil to the inlet side of the pump. More particularly this invention relates to means for automatically adjusting the pressure of the said spring on said valve to start the operation of the burner at a preset low fuel burning rate and thereafter regularly to increase the lfuel burning rate of the burner to a preset maximum rate.

It should be understood that it is common practice with smaller sizes of pressure atomizing burners to use on-oif controls and start up the burner at full preset capacity whenever heat is required. Since the burners are forced draft burners with very little air circulation through the combustion chamber when the burner is turned off, the sudden injection of full load oil and air into the combustion chamber may cause an explosive starting condition which only settles down after the products of combustion attain full velocity into and through the chimney.

With larger sizes of pressure atomizing burners this starting problem is serious and may be dangerous and many different types of controlling devices have been developed and used to alleviate the condition. i

It is a primary object of this invention to provide means for use with a pressure atomizing oil burner automatically to start such a burner at a reduced rate of oil supply thereto and after starting to increase gradually the rate of oil supply up to a preset limit.

It is a second object to provide means for use with a pressure atomizing oil burner automatically to start such a burner with both a reduced rate of oil supply thereto and a reduced rate of combustion air supply thereto and thereafter gradually to increase both the rates of oil supply and air supply up to preset limits.

How these and other objects are attained will be made clear on reference to the following specification referring to the attached drawings in which FIG. l is a schematic fragmental drawing in partial section of a typical fuel unit as used with a pressure atomizing oil burner and showing the attachment thereto in fragmental partial section of a structure with which one form of the present invention may be practiced.

FIG. 2 is a more complete showing of an hydraulic motor of this invention with its attachment to a fragmental part of the fuel unit of FIG. 1.

FIG. 3 is a fragmental enlarged portion in partial section of the structure shown in FIG. 2.

Like numerals of reference refer to like parts in the several FIGURES of the drawings.

It is common practice well known in the art to use either one or two stages of pumps in a fuel unit of a pressure atomizing oil burner and either one or two oil lines between the oil storage tank and the fuel unit. In the present disclosure whether one or two pump stages are used or whether one or two oil lines are used is a matter of choice. Therefore for simplicity of disclosure it is to be understood that the disclosure considers only a fuel unit with a single fuel pump for the supply of oil under pressure from theV oil storage tank to the nozzle line of the burner and it is to be understood that the pressure regulating or relief valve returns the excess oil from the flfiice nozzle line to the inlet side of the pump so that only a single (suction) line is required to extend between the storage tank and the fuel unit. However, it is also understood that the new and useful structure and arrangements of this invention may be used equally well with fuel unit arrangements using two stage pumps and/or two tank lines.

Referring now to FIG. 1 of the drawings a commonly used type of fuel unit comprises a one piece hollow body 11 having an open end closed by a cover 12 sealed thereon by cap screws 13. Within the oil inlet space 14 -a cylindrical oil filter screen 15 has its open end linished with a V sectioned metal edge 16 and its other end substantially closed by a metal cover 17 having a cylindrical ilange 18 fitting closely over V sectioned metal edge 19. Metal end cover 17 of screen 15 has a pair of spring fingers 20 formed outwardly therefrom to press against the inside of cover 12 of body 11 to press the metal edge 16 of screen 15 into recess 21 of space 14 to 4abut O-ring 22 to seal screen 15 into recess 21. It is seeen that as pump 23 draws fuel oil from a storage tank (not shown) and inlet port 24 into inlet space 14, the oil must pass through strainer 15 to the interior 25 thereof and on through conduit 26 to pump 23.

Pump 2'3 is of a type well known in the art in which a toothed pinion 27 driven by a coaxial shaft (not shown) has one or more of its teeth meshing with adjacent internally toothed mating gear 28 carried coaxially in pump body part 11g to rotate eccentrically with rpect to pinion 27. Stationary crescent shaped part 29 has its inner concave surface 30 and its outer convex surface 31 mating respectively with the convex tooth top surfaces of pinion 27 and the concave tooth top surfaces of gear 2S as shown. Pump body part 11g includes a pair of stationary pump gear face plates (not shown) axially spaced to include closely conned between them by bolts 32, pinion 27, gear 28, stationary crescent 29 and an annular ring part 33 of body 11g.

With pinion 27 driven to rotate in the direction shown by the arrow and driving with it gear 28, oil is drawn from conduit 26 through conduit 34 into the intertooth space 35 of pinion 27 and gear 28 from where the oil is carried in the tooth gaps of pinion 27 and gear 28 on the respective sides of part 29 to intertooth space 36 from where the oil is discharged under pressure through conduit 3K7 to oil pressure space 38 around regulating valve seat plug 39 above valve disk 40 set into the upper end of Valve piston 41 biased towards plug39 by spring 42 strained between regulating pin 43 and spring supporting washer 44 at its lower end and valveppiston 41 at its upper end.

Outlet port 45 located axially through plug 39 permits oil to pass from oil pressure space 38 to nozzle line 46 and oil burner nozzle 46a whenever the oil pressure in space 38 is suicient to move valve piston 41 with valve 40 downwardly away from valve seat 47 around outlet port 45 at the lower end of plug 39.

Valve piston 41 is axially slidably sealed into sleeve 48 which is slidably sealed into body bore 49 by 0-ring 50. Valve supporting plug 51 threaded into bore 49 supports sleeve 48 axially in bore 49 as shown and is sealed to body 11 by gasket 52.

As is common in the operation of pressure atomizing oil burners when there is a call for heat the fuel unit driving motor (not shown) is energized and a combustion air supply fan (not shown) as Well as pump 23 are put into operation. As pump 23 pumps oil from conduit 26 to conduit 37, the oil pressure builds up in outlet space 38 and in oil conduit 53. See also FIGURES 2 and 3.

A particular feature of this invention is the structure and operation of the hydraulic motor 54 comprising an open ended cylinder 55 closed at one end by cylinder head 56 athreadedly engagedtherew-ith and sealed thereto by O-ring 57. The ,other Yend of cylinder 55 is closed by cylinder head 58 threadedly, engaged therewith and sealed thereto by O-ring 59. Oil conduit 53 is connected, as shown, :through tube-,to-pipe 'litt-ing 60, fheaded bushing :61 and :lock bushing .62 `to 'the interior of cylinder 'head 56.

Thefrate of oil ow in either direction through con- ,duit 53;is governed by the small orifice 63 in oriiice disk :64 securedinposition in bushing .61, as shown, by hollow bushings 65, 66. Bushing 65 may be filled with oil filtering A.material .67 if desired.

. `Cylinder head V58 of Yhydraulic motor 54 is secured as vshown,'.to=plug 151 Aof body 11 by guide bushing l68 for Y regulating pin 43.

Piston rod guide bushing 69 for free piston rod 71 Aof free piston 70 is clamped in position in cylinder head 558 `by cylinder 55.

Push crank stop means 72 xed .to crank pin 73 jour- Enalled at vopposite ends in cylinder head 58, as shown, :is biased for counterclockwise movement about the axis `of pin 73 by oil .pressure regulating spring 42 ,and limited in counterclockwise motion by -low pressure limit adjust- -ing screw 74 set into cylinder head 58 as shown and sealed therein by a cover screw 75.

Free vpiston 70 is slidably sealed into cylinder 55 by O-ring 76. Return spring 77 strained between guide bushing 69 and piston 70 biases piston 70 away yfrom Lpiston rod 71. As the pressure of oil in fuel unit pressure space ,38 is built up by the starting of pump 23 on a call -for heat Ithe pressure .of oil rin conduit 53 will move oil slowly through orilices63 in disk 64 `and =iill space 78 limited by piston 70 and cylinder head 56. As the volumeof oil in space 78 increases piston 70 is moved slowly into cylinder 55 against the bias of spring77 and after adelay time determined both by the size of orifice l63 and the minimum `oil pressure as set by screw 74 '(see FIG. 2), piston 70 will contact one end of rod 71 to ymove 'the-other end into contact With-'push crank 72 \to rotate crank 72 clockwise lagainst the bias of spring 42 slowly to increase the pressure yof valve 40 on seat 47 to increase the oil pressure maintained in space`38 until crank 72 has moved from its position shown in FIG. 2 to its position shown in FIG. l where the clock- `wise motion of crank 72 is stopped by -itscontact with upper pressure limit screw 90 setA into cylinder head 58 as shown and'sealed therein by a cover-screw 75.

With my new and useful hydraulic motor 54 attached to a well known fuel -unit of `a Well known type of pressure atomizing oil burner, Yas shown, and if the full requirement lof combustion air is started into the combustion chamber at the time there Vis a call for heat and oilpump 23 is started and if minimum pressure screw 74 is set to require an oil pressure in space 38 of, say, 100 psi. to -lift -valve 40 from valve seat 47 then the lirejwill Yhe started immediately with oil Yflow through 4the nozzle limited by thenozzle oil passage and the pressure ofthe oil. To illustrate with an example; if a nozzle rated -to pass oil at a certain number of gallons per hour requires an oil pressureof 3,00p.s.i.'to deliver-its rating thenlit'will deliver about one half its rating `at 100 p.s.i.; :in 'heating boilers it is'not uncommon to equip ya boiler 4rurnace of vapartment bouse size with two burners so I'that each Vburner of half boiler size can 'be started lby itself without making thefre startttooexplosively; thus a boiler requiring thirty gallons of oil per hour at full zload would'be equipped with two iifteen-gallon burners;

lbutra ,single burner equipped with the present hydraulic Arnotorlor startinga .burner `at about one half rating and gradually ,bringingthe ,lire up to full sizewould Ybe cheaper .to install and control and vwould be `more quiet and cleaner in operation.

-In-the present case if screw 74 weresetrto give a minimum' oil pressure `in vspace 38 of V100 p.s.i. yand screw were set to give a maximum oil pressure in space 38 of 300 psi., then on a call for heat, the burner would start up with a half size re and after a delay to give the iire time to get running smoothly the re would gradually increase without commotion to its rated size.

As described above the burner would start with oil being supplied at half rating and air being supplied at full rating which Vfor a few minutes would be theoretically inetlicient because of the waste of heat up the stack with the excessair. Actually, however, the greater ow of initial air in relation to the oil rate Will get the air and products of combustion moving faster to clear the combustion chamber sooner than would otherwise be the case and also vthe lire would start Wholly clear of soot.

'Howeven just as my present means is Versatile vin modulatig the oil supplied to the flame it is seen that by air crank lever 79 secured to crank pin 73 outside of cylinder head 58 (see FIG. l), a combustion air ow damper 90 operatively applied to combustion air inlets 91 on the inlet side of the combustion air fan housing, 92, as shown, can be engaged to modulate the air supplied to the burner as a desired function of the oil iow rate. t

Again it should be noted that as shown in FIGS. 3 and 1, if a variable opening cock V86 with a modulating handle 81 is used to connect through tube 82 the space 78 in the head 56 end of cylinder 55 with the low pressure space 14 in the fuel oil unit, the forward or rearward motion of piston 70 can be controlled `as desired during Ythe .operation of the burner. This means of course that any of the available modulating types of condition responsive controllers can be used to modulate the re size of the burner to the load requirement over the one half to full load ability of the burner.

Although the fuel unit here described is a commercially available unit well known in the art, to complete the description thereof it might be added that when the pressure of oil in space `38 exceeds the p.s.i. for which crank 72 aud-pin 43'have set spring 42, valve piston 41 is forced `to back Valve 40 away from its seat 47 and oil goes through port 45 to nozzle line 46. Then oil pumped by pump 23 is excess of that taken by nozzle line 46 and control ilineV 53 forces piston 41 further downward until cylindrical oil passageway 83 is opened to portt84 through sleeve 48 Vand the excess oil entering passageway 83 fromspace 38 through passageway 85 in sleeve 48 is relieved Vto low pressure conduit 86 through port 84 and cylindrical passageway 87 formed around sleeve 48.

vIt vshould also'Y be noted that in these commercial fuel units as shown the pumps like Z3 are always provided with excess pumping capacity and certain leak spaces, not shown, are provided `to allow some of the excess capacity to leak back to the low pressure side of the pump without passing regulating valve l0-'47. For this reason when Ythe need for heat has been supplied and the burner is shut down, oil `from space 78 in cylinder 55 will tbe forced by spring 77 and piston 70 yto return through oriiice 63 ,and conduit 53 yto fuel Vunit space 38 from where it leak back to the low pressure side vof pump 23.

Having recited some Yof the objects of my invention and having illustrated and described at least one form in which my invention may .be practiced and described its operation, I claim:

1. A .pressure atomizing type of oil burner fuel supply system including an oil pump enclosure including means forming an oil inlet space, means forming an oil outlet space, pump means for withdrawing oil from said oil inlet space and discharging said oil under pressure to said outlet space, means Vforming a nozzle oil port leading from said oil outlet space to the outside of said structure, means forming a return oil port connecting said oiloutlet space with said oil inlet space, a valve piston slidably sealed within said oil outlet space for movement in one direction serially to close said return oil port and said nozzle oil port and movement in the other direction serially to open said nozzle oil port and said return oil port and said piston being biased by the oil under pressure in said oil outlet space towards its open position of both said ports, adjustable means resiliently biasing said valve piston against the pressure of oil in said oil outlet space, means limiting the adjustment of said adjustable means between selected high and low values of the oil pressure in said oil outlet space, said adjustable means including a hydraulic cylinder with a free piston slidably sealed therein, resilient means biasing said free piston towards one end of said cylinder, a restricted oil passageway connecting said one end of said cylinder with said oil outlet space, a free piston rod shorter than said cylinder extending from the other end of said cylinder to be moved outwardly thereof by said free piston after said free piston has been moved inwardly of said cylinder for a time preset by the ow of oil through said restricted passageway from said oil outlet space, and means adapting said free piston rod to increase the bias of said adjustable means on said valve piston as said free piston rod moves outwardly of said cylinder.

2. In combination, a pressure atomizing nozzle for an oil burner, means forming an oil inlet space, means forming an oil outlet space for oil under pressure, means including a positive pressure pump for forcing oil from said inlet space to said outlet space, a nozzle conduit connecting said nozzle with said outlet space, a return conduit connecting said outlet space receiver with said inlet space, a piston valve in said return conduit, and rst resilient means adapting said piston valve to open in progressive response to the oil pressure in said outlet space, said first resilient means biasing said piston valve towards its closed position, oil control means for setting a minimum pressure at which oil will be delivered to said nozzle when said pump is activated, means for determining a preset time during which oil at said minimum pressure will be delivered to said nozzle and means for thereafter gradually increasing the pressure of said oil at said nozzle to a preset maximum, said oil control means comprising a hydraulic cylinder, a free piston slidably sealed in said cylinder, second resilient means biasing said free piston towards one end of said cylinder, 4a control conduit connecting said outlet space with said one end of said cylinder to cause said oil under pressure from said nozzle conduit to move said free piston inwardly of said cylinder towards the other end thereof, means forming a variable orifice in said control conduit to preset the rate of movement of said free piston in said cylinder, a free piston rod slidably supported axially in the other end of said cylinder to be effectively engaged by said free piston after said preset time and means engaging said free piston rod after said preset time with said first resilient means biasing said piston valve towards its closed position.

3. A pressure atomizng type of oil burner fuel supply system having an atomizing nozzle, an oil pump enclosure including means forming an oil inlet space, means forming an oil outlet space, pump means for withdrawing oil from said oil inlet space and discharging said oil under pressure to said outlet space, a nozzle conduit connecting said outlet space to said nozzle to deliver oil thereto and a pressure relief valve spring biased toward its closed position by-passing said pump to determine the oil pressure at said nozzle, together with timing means for progressively increasing the biasing pressure of said on said valve gradually to increase the oil pressure on said nozzle gradually to increase the rate of oil discharge from said nozzle, said timing means including stop means reactively supporting the end of said spring opposite said Valve, said stop means being movable between preset limits toward and away from said valve to determine the instantaneous biasing pressure put on said valve by said spring together with a hydraulic cylinder having a free piston slidably sealed therein resiliently biased towards one end thereof, restricted orice means connecting said one end of said cylinder with said outlet space and a lost motion free piston rod extending from the other end of said cylinder effectively to engage said free piston and said stop means progressively to increase the bias of said spring on said valve after said free piston has moved a preset distance.

4. The oil burner fuel supply system of claim 3 including a combustion air control lever secured to said stop means to move therewith to vary the rate of combustion air supply to said burner as the oil supply to said nozzle is varied by said timing means.

5. The oil burner fuel supply system of claim 3 including means for varying the time required for said free piston to move said preset distance said means including a bleed port through the wall ofv said cylinder between said free piston and said restricted orifice means, a variable orice valve for controlling the oil ow from said bleed port and means for varying the orifice size of said valve as desired.

References Cited in the le of this patent UNITED STATES PATENTS 1,899,396 Ray Feb. 28, 1933 2,145,404 Osborne Ian. 31, 1939 2,178,672 Perkins Nov. 7, 1939 2,209,856 Smith et al. July 30, 1940 2,364,489 Taylor Dec. 5, 1944

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