US2193659A - Liquid fuel burning system and regulating apparatus - Google Patents

Description

March 12,-1940. F.' R. WHITCOMB 2,193,659

LIQUID FUEL BURNING SYSTEM AND REGULATING APPARATUS Filed July 25, 1936 In 0677 207. R W

Patented Mar. 12, 1940 Zddhtdh PATENT orri cs LIQUID FUEL BURNING SYSTEM AND REGULATING APPARATUS Forrest R Whitcomb, lwi nchendcn, Mass. Application-1 July 25, 1936, Serial No. 92,613

' 7 Claims.

This invention relates to liquid fuel burning systems and apparatus, and to a device responsive to a condition that is apt to be variable as,

for instance, the pressure in a steam boiler, for

controlling the flow of fuel tothe burner in such manner as to maintain the condition, as the steam pressure, substantially constant. 7

'My invention particularly relates, although it is not necessarily restricted, to the so-calledvaporizing type of liquid fuel or. oil burner; and its fuel supply and control system. A vaporizing type of oil burner consists of a burner having small-openings through a wall thereof through which a combustible mixture. of oil vapor and air flows and burns outsidethe burner; The liquid oil that is supplied under pressure to the burner is first vaporized by passing it througha vaporizing tube that, usually, is heated bythe flame of the burner, The oil vapor is discharged at a substantial velocity through a small orifice into a combining or mixing tube where it entrain's' suf ficient air for combustion; and the mixtur e is passed into the burner. Here'tofore, the regulation of the flame has been accomplished by controlling the flow of oil vapor by a needle valve the point of which projects .into the fuel orifice to regulate the eifective cross-sectional area thereof. a v a Vaporizing the oil usually results in the formation of solid carbon particles which flow with the carbon particles are too large to passthrough the orifice and hence collect around andin' it and thus plug it frequently; and oneof the functions of the needle valve is to break away'the" carbon deposit so that the fuel can pass therethrough although ultimately the end of the needle burns of? to such an extent that the needle valve point cannot keep the passage clear. the fuel regulating valve is objectionable since it has to be packed against the rather high pres; sure and high temperature of the oil vapor and in practice cannot be maintained constantly tight so that oil vaporleaks out and ignites and backfires the burner and necessitates the restarting of the fire. 4

An object of the present invention is the provision of a vaporizing type of burner and a fuel supply therefor wherein regulation of the fuel supply to the burner is obtained by control of 'the liquid fuel so that troubles from leaking oil vapor.

This location of predetermined condition as, for instance, a con stant steam pressure in the boiler. It is an object of the present inventionto provide a novel oil fiow regulating system automatically responsive to the-predetermined condition, as the steam pressure, or to a predetermined manual setting at will, to control'the fiow of oil in such manner as to maintainthe predetermined condition constant. I

In particular it is an object of the invention to provide an improved fuel regulating apparatus so arranged as to provide for a high flow of oil corresponding usually to the maximum capacity of the burner and alow how of oil corresponding usually to the amount of oil necessary to keep the burner in reliable operation, with means responsive to the predetermined condition as the steam pressure or rate of. combustion desired to effect the flow of oil at either high or low volume or any point in between, in accordance with conditions.

In supplyingoil for the low flame operation of the burner the size ofjthe orifice through which the liquid fuel passes is relatively minute, espe cially for a low maximum capacityburner. Such a small orifice ordinarily cannot be maintained clear of obstruction, notwithstanding that the oil maybe filtered as completely as is practicable prior'to its passage to the orifice. The usual fuel oils, at least those present in common use, seem to contain solid matter or waxes that cannotbe where there is a sharpdrop in pressure'and plug the orifice. v

A further object of the present invention is the provision of an oil-regulating apparatus wherein the control valve is so arranged that it is caused to move frequently enough to dislodge any collection of solid matter that may tend to plug the orifice and so keep the orifice clear.

filtered out but which collect at a smallorifice.

. 0 Another object of the invention is an oil sup:'

ply system having an oil-regulating apparatus that operates tornaintain a constant rate of combustion, for any setting thereof, irrespective of a fluctuating oil supply pressure.

A further object of the invention is the provision of an oil regulating valve subject both to the pressure of the oilsupply and also to the pressure of-th'e oil vapor, both of which can vary, and so arranged as to maintain a constant oil vaporpressure notwithstanding variations of oil supply pressure and varying conditions, such as varying vaporizing temperatures, that tend toward varying vapor pressures. The valve further is so arrangedthat it can be adjusted, either manually or otherwise, for different vapor pressures and to maintain constant the pressure for which it is adjusted.

A further object of the invention is the provision of an oil regulating apparatus so constructed and arranged that it is particularly sensitive to small variations of steam pressure in the boiler heated by the burner and hence is capable of maintaining the steam pressure constant within close limits.

A yet further object of the invention is the provision of an oil regulating apparatus having a steam pressure controlled high flame valve that is so balanced or constructed that it is unaffected by variations in the pressure of the oil that it controls.

A further object is generally to improve upon oil burning systems and regulating apparatus therefor.

Fig. l is a plan view illustrating an oil burning system embodying the present invention associated with a steam boiler.

Fig. 2 is an enlarged sectional detail of the filter in the oil vapor pipe of thesystem.

Fig. 3 is a side elevation of the pressure regulating apparatus forming a part of the present invention.

Fig. 4 is a sectional view taken along line 4-4 of Fig. 3.

Fig. 5 is a section along line 5-5 of Fig. 4.

Fig. 6 is a sectional detail of the supporting plate for the high flame valve.

The liquid fuel burning system embodying the present invention is hereby shown associated with the steam boiler I!) having the combustion chamber I2 in which the burner I4 is located. The burner is provided with orifices I6 through which a combustible mixture passes and is burned above the burner, and a combining or mixing tube l8 through which the mixture of oil vapor and air is directed into the burner. Liquid fuel is supplied under regulated pressure through a pipe 20 having a pass 22 that extends through the flame zone or combustion space of the boiler in a position to be sufficiently highly heated to convert the oil therein into a vapor. The vapor passes through the pipe 24 and through a small orifice in a nozzle 2| and discharges into the tube 18 wherein it entrains sufficient air for good combustion.

The flow of the liquid oil is regulated by a flow regulating device 23, the operation of which is controlled by a steam pressure in the boiler through a steam pipe 25. Oil is supplied preferably under pressure to the regulating device through a pipe 26 from an oil pump 28 which draws oil from a suitable supply source. The pump 28 may comprise a single acting pump having a reciprocating piston 30 operated by a solenoid 32 the circuit of which is controlled by a switch 34 so arranged that when the piston is at the bottom of its working stroke the solenoid is energized and raises the piston. The solenoid is de-energized at the top of its suction stroke and the piston returns on a delivering stroke by spring means or the equivalent not shown, the springs supplying the pumping pressure.

The flow regulating apparatus 23 comprises a lower cylindrical casing 36, see especially Figs. 3 and 4, the open lower end of which is closed removably by a plug 38 having a screw-threaded connection with the end of the steam pipe 25. The plug contains a cylindrical recess in its upper face in which the cylindrical lower open end 40 of an expansible bellows 42 is secured as soldered in a fluid tight manner. The bellows 42 is preferably composed of metal having a plurality of annular corrugations so that it is capable of lengthwise expansion. The upper end of the bellows is closed and a piston 44 bears loosely thereagainst, the piston being cupped at its lower end to receive the upper end of the bellows so that the two are held against relative lateral displacement.

The piston 44 is capable of free axial movement within the circular opening of a transverse wall 46 of the casing 36, which wall holds the piston against undue axial displacement, although ordinarily the piston is out of engagement with said wall. The piston is screw-threaded onto the lower end of a piston rod 48 which extends through the upper end of the casing 36. A pressure adjusting plug 59 loosely surrounds the piston rod and is screw-threaded into the upper end wall 52 of the casing 36 and bears against the upper end of a compression spring 54. The lower end of the spring bears against a washer 56 which loosely surrounds the lower end of the piston rod and is seated normally upon the top of the piston 44. Said washer, however, is larger in diameter than said piston and can overlie and bear upon the wall 46 of the casing 36 at times of insufficient steam pressure so as to take the load of the spring from the bellows at such times and prevent undue collapse of the bellows. The pressure adjusting plug 50 is provided with opposed spanner openings 58 by which the plug can be rotated to adjust the compression pressure of the spring on the piston and hence adjust the steam pressure at which the regulating device is maintained to operate.

A valve casing 60 is disposed above the top of the casing 36 and is secured in spaced relation therewith by opposed sets of upper and lower spacing tubes 62 and 64 which are received loosely on upstanding tie rods 66 screw-threaded in ears 68 of the casing 36 and passed loosely through ears 10 of the valve casing 60, the valve casing being clamped against the ends of the upper casing tube 60 by nuts 12 screw-threaded on the upper ends of said tie rods. The valve casing 60 is provided with a liquid fuel inlet passage 14 and a liquid fuel outlet passage 15. Communication between said passages is controlled by a high flame valve member or stem 18 having a cylindrical upper end terminating in a conical valve face 89 and having an enlarged lower end 92. The valve stem 18 is adapted for free vertical reciprocatory movements in a vertical cylindrical stem passage 84 that communicates with the inlet passage 14 through a conduit 86 and with the outlet passage 18 through a conduit 88, the conical end of the valve stem controlling the flow of fluid through the passage 88. The lower end of the valve stem 18 is fixed to the middle of a circular stem-supporting disc 90 having upper and lower annular shoulders 92 and an intermediate outstanding annular flange 94. An upper flexible corrugated metal bellows 96 has its lower open end surrounding and secured in an oil tight manner as soldered to the upper annular shoulder 92 and has its upper open end similarly secured to a cylindrical boss 98 of the valve casing 60, thereby surrounding the valve stem. A second lower flexible metal bellows I00 has its upper cylindrical open end surrounding and seemed in an oil tight manner to the lower annular shoulder 92 of the disc vertically extended are free to expand along their own axis and of oil in. the interior of the bellows is plate. are received on the tie rods 86 and are clamped between the lower and upper spacing tubes 62 and 64. The valve stem 18 is provided with an axially directed oil channel Hi6 which permits free communication "between the high pressure oil inlet M and the interior. of the upper bellows 96. The valve supporting disc 9i) is provided with an oil channel H28 which establishes communication between the two bellows. This arrangement provides a packlessvalve, that is, one that is permanently oil tight without the use or a packing gland and one wherein the pressure of the inlet oil on the 'valvestem is balanced so that there is no material tendency for the valve stem to move ineither direction due to the oil pressure.

The valve stem sponding' movements of the piston rod 48. To this end a yoke H is fixed to the upper end of the piston rod {58 and has oppositely disposed arms HZ which are located qn'opposi'ter sides of the valve bellows and terminate in vertically adjustable screws H 4 having conical upper ends Ht above which extend locating projections H8. A valve supporting plate i213 has ears 522 which rest on or. fulcrum upon the conical'ends N6 of said screws and has apertures HM through which the locating projections H8 are loosely extended. This arrangement gives the plate freedom for rocking movement in directions transversely ,of the line through the screws. The plate is providedwith a cup-shaped recess E26, see especially Figs. 4 and 6, in which the valve stem supporting disc '90 is located. The bottom wall I28 of said plate is provided with a pair of diametrically opposed projections or fulcrums I 30 angularly displaced 90 from the line of the screws H4 and, which fulcrum supports the outstanding flange $2 of said disc 90. Said tions and the fulcrum support for the plate W2 is capable of universal pivotal movement with respect to the operating yoke H0, and hence the valve member '78 is free for vertical movement about its own vertical axis irrespective of the alignment of the operating yoke Hi). With this arrangement both theoperating piston M and the valve member it are free for movement with a minimum of sidewise restriction since the parts are supported entirely on flexible bellows which to tilt sidewise in any direction. The valve is thus capable of responding in a very sensitive manner to a fluctuation of steam pressure.

As has been stated above, the valve member '18 is free from influence by the high pressure oil since the pressure of oil on the upper and lower ends of the valve member is substantially equal, the bellows Qt and lilil' being filled with oil at the pressure of the inlet oil. The pressure supported by the plate Hi l so that the bellows remain of constant length regardless of fluctuations of oil pressure. Hence the movement of the valve member under control of the steam actuated bellows 42 is independent of the oil pressure and is governed solely by the steam pressure.

The valve as thus described is adapted to open ble' diaphragm. I32 sheethaving a down-turned rim or flange I 33 neck and, i8 is reciprocated by corre.

opening in the diaphragm I39 disc by virtue of these projec- 'ent resiliency determined minimum amount of the adjusting screw vapor pressure that causes the movements of the valve are p are sufficient in amplitude burner at times when the high flame valve 78 is closed; The low flame valve comprises a flexiformed of a thin flat metal which surrounds an upstanding annular flange 54 0f the valve casing till and is secured to said flange in an oil tight manner, as by soldering. The shallow loil chamber I36 located under the diaphragm and within said flange communi cates with the outlet passage 78 through a small connecting passage 438 age "14 through avalve passage ME) and an intermediate chamber MZthat is open to the inlet passage 'i-i. An exteriorly and interiorly' screwthreaded neck 24 2 is fixed to and upstands above the diaphragm i3?) and a valve carrying and adjusting screw M is screw-threaded in said neck. A packing cap M8 is screw threaded upon said with the packing material therein, seals" said screw against leakage of oil thereabout. The. screw M6 has a slender valve rod or stem I56 extended axially therethrough and fixed thereto. Said rod extendsthrough the central and through the valve passage Mt and terminates in" a conical valve member 552 disposed in the passage M2 in positions to control the entrance of fuel through said passage MB. i y Saidvalve member E52 by reason of said passage I3l is responsive to pressure conditions in the'outlet passage 16 and hence to the pressure of the oil vapor conditions in. the: vapor generator 22. 'When the pressure in the outlet passage "it is relatively high due to the valve it being open the pressure acts on the under side of the diaphragm M2 to flex it outwardly thereby moving the low flame valve I52 upwardly and sealing the entrance to the pas sage I452." When,xhowever, the steam pressure in the boiler reaches a sufiiciently high point to cause the. high flame valve '13 to close, the pressure inthe outlet passage 76 drops due to the discharge of vaporized fuel into the burner. When the pressure is sufliciently low thediaphragm I39 flexes downwardly-due. to its inhermember 5Qt0 open thereby to admit the prefuel to pass to the burner. The minimum amount of fuel may be varied within limits by changing the setting of Mt. The low' 'fla1'ne valve maintains a constant pressure-oi oil vapor at the nozzle 28 for if the pressure tends to rise in the outlet passage it the low flame valve closes somewhat; and if the pres sure drops the low flame valve opens somewhat.

The operation" of the low flame valve is such that it is in continual reciprocatorymovement in order to maintain a constant pressure. condition in the outlet passage. When the valve opens to admit oil the oil is vaporized and builds up a partial closing of the valve member. The valve. member stays in this semiclosed position until the oil has been consumed and the pressure drops whereupon the valve again opens. Such movements of the valve serve to maintain a constant oil vapor pressure. The response-of the valve to varying oil. supply pressures is similar. Such further frequent enough and to dislodge solid particles from around the valve member and hence to keep the and with the inlet pasand causes the low flamevalve A filter H4 is located in the oil vapor pipe 24 between the oil vaporizing pipe 22 and the nozzle 26 to prevent the passage of solid matter into the nozzle. The filter, as illustrated in detail in Fig. 2, comprises a gas tight casing I56 having inlet and outlet passages I58 and IE0, respectively, between which a filter element I62 is located in such manner that all of the vapor is constrained to pass through the filter element. The filter element comprises a porous disc of ceramic material such as carborundum or the like, molded into shape and having a plurality of pores or small tortuous passages therethrough that are sufficiently small to entrap carbon and other solid particles in the vapor stream and prevent them from passing to the orifice. The combined area of the small pores or passages through the filter element is sufficiently great so that the filter element does not offer any deleterious resistance to the flow of heated vapor even after long periods of use. The use of the filter element not only prevents the orifice in the nozzle 26 from clogging and thereby permits the fuel regulation to be effected from the liquid oil side of the system but also provides a cleaner flame since it entraps the small solid particles that would otherwise pass through the orifice and into the flame to form soot. The filter preferably is located above the burner or where it receives sufiicient heat from the flame thereof to prevent it from condensing the oil vapor.

I claim:

1. An oil burning system including an oil burner, oil flow regulating apparatus for said burner comprising high and low flame valves having movable valve members and a common outlet passage connected with said burner, means [or operating said high flame valve member to change the oil pressure in said outlet passage, and operating means for said low flame valve member responsive to a predetermined low oil pressure in said outlet passage to maintain said pressure substantially constant and responsive to an elevated pressure to move said low flame valve member into closed position.

2. An oil burning system including an oil burner, oil flow regulating apparatus for said burner comprising high flame and low flame valves having valve members and a common inlet passage and a common outlet connected with said burner, operating means for said low flame valve member responsive to a predetermined low oil pressure in said outlet passage for maintaining said pressure substantially constant, and operating means for said high flame valve member to open. and close it to change the pressure of oil in said outlet passage between wide limits and to control the operation of said low flame valve member.

3. An oil burning system including an oil burner, oil flow regulating apparatus for said burner comprising a low flame valve having inlet and outlet passages, said outlet passage being connected to said burner, means responsive to a low oil pressure in said outlet passage for controlling the opening of said valve, and a high flame valve having means for admitting high pressure oil into said outlet passage to effect the closing of said low flame valve.

4. An oil burning system including an oil burner, oil flow regulating apparatus for said burner comprising a valve casing having inlet and outlet passages, said outlet passage being connected with said burner, a movable valve member controlling the flow of oil between said inlet and outlet passages, a flexible diaphragm at all times responsive to oil pressure in said outlet passage and at the burner, and an adjusting screw carried by said diaphragm and carrying said valve member, said screw being adjustable in the line of operation of said valve member whereby to determine the flow of oil through said valve at predetermined settings of said valve member, a second passage connecting said inlet and outlet passages, and a second valve member in said second passage operative to admit oil into said outlet passage independently of said first valve member and in amount sufiicient to act on said diaphragm and close said first valve member and increase the supply of oil to the burner.

5. An oil burning system including a burner, oil flow regulating apparatus for said burner comprising a valve casing having inlet and outlet passages, said outlet passage being connected with said burner, a movable valve member controlling the flow of oil between said passages, a flexible diaphragm at all times responsive to oil vapor pressure at the burner operatively connected with said valve member for varying its position in response to different oil pressures on said diaphragm, and means for adjusting the relative position of said valve member independently of the action of said diaphragm, a second passage connecting said inlet and outlet passages, and a second valve member in said second passage operative to admit oil into said outlet passage independently of said first valve member and in amount sufficient to act on said diaphragm and close said first valve member and increase the supply of oil to the burner.

6. An oil burning system including a burner, oil flow regulating apparatus for said burner including a valve casing having inlet and outlet passages and an annular flange, said outlet passage being connected with said burner, a flexible diaphragm secured to said flange, said casing having a valve passage leading from said inlet passage and opening into the space under said diaphragm and a second passage establishing communication between said space and said outlet passage, said diaphragm being at all times responsive to burner vapor pressure, a valve member in said first passage, and a valve adjusting screw having a screw-threaded connection with said diaphragm and carrying said valve member for adjusting the setting of said valve member to regulate the rate of operation of said burner, a second passage connecting said inlet and outlet passages, and a second valve member in said second passage operative to admit oil into said outlet passage independently of said first valve member and in amount sufiicient to act on said diaphragm and close said first valve member and increase the supply of oil to the burner.

'1. In an oil burner system having a burner, means providing an orifice for discharging oil vapor into the burner, means for supplying oil under pressure, the combination therewith of valve means for controlling the flow of oil from said supply to said vaporizing means, said valve means having means responsive to pressure of the oil vapor and operative automatically to maintain a constant pressure of oil vapor irrespective of variations of pressure of the oil supply, and means for admitting oil to said vaporizing means independently of said valve means in a quantity sufficient to increase the vapor pressure and effect the closing of said valve means.

FORREST R.WH1TCOMB.;

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