US2633864A - Furnace fuel control - Google Patents

Description

P 7, 1953 J. o. THORSHEIM FURNACE FUEL CONTROL Filed April 5, 1948 2 SHEETS SHEET l J. O. THORSHEIM FURNACE FUEL CONTROL April 7, 1953 2 SHEETSSHEET 2 Filed April 5, 1948 Zmnentor JOSEPH 0. 7/10/7191A67/7 II k Patented Apr. 7, 1953 FURNACE FUEL CONTROL Joseph 0. Thorsheim, Minneapolis, Minn., as-

signor to Minneapolis-Honeywell Regulator. Company, Minneapolis, Minn., a corporationof Delaware Application April .5, 1948, Serial No. 19,120

4 Claims. 1

This invention relates to a furnace fuel control for regulating the flow of oil to an oil burning furnace. More particularly, the invention is concerned with a control device which provides for a low rate of fuel fiow to maintain a pilot flame inthe furnace and at least one other larger rate of fuel flow to provide high fire operation of the furnace.

There are numerous control devices which provide the above mentioned furnace operation but many of themperform in an unreliable manner. Thosewhichrely on the metering of fuel through a small orifice to provide low fire operation of the furnace, probably give the least reliable performance, This is usually due to the gumming of the small orifice.

One of the objects of this invention is to provide a furnace fuel control which will provide an extremely low and uniform rate of. fuel flow for maintaining a pilot flame in the furnace, without having the fuel flow through a small passageor orifice.

Another object of the invention is to provide a control which uniformly and regularly delivers a metered charge of fuel to a furnace.

A further object of the invention is to provide a control which delivers metered charges of fuel to the furnace and which has. means for varying thesize of the charges.

' A still. further object of the invention is to provide a control which has a valve associated there.- with which will cut off the flow of fuel if one or more of a plurality of undesirable conditions arise.

Another object of the invention is to provide a control having a simple means for manually opening a safety valve therein and to reset a condition-responsive valve-actuator therefor.

Another object of the invention is to provide a; compact controlhaving fuel metering'means and a safety valve with concealed passages connecting them.

Still further objects of the invention will be come apparent upon reading the following de tailed description of the invention in conjunction with the accompanying drawings wherein:

Figure 1 is an elevational view .of the control with portions thereof broken away;

Figure 2 is a plan view of the control with its cover removed and Port-ions thereof broken away;

Figure 3 is a cross-sectional view of the safety valve of the control;

Figure 4- is a cross-sectional view of an accumulator in the control, taken on line 4-4 of Figure l;

Figure 5 is a cross-sectional view of a control valve in the control, taken along line 5-5 of Figure 1 and with parts thereof broken away and removed;

Figure 6 is a cross-sectional View of the abovementioned control valve taken along the bearing plane surface of the valve;

Figure 7 is a plan view of a power adjusting" means for the accumulatorwith portions thereof broken away and the accumulator shown in cross-section;

Figure 8 is a sectional view taken on line 8-8 of Figure 1; and

Figure 9' is a sectional view taken on line 9--9 of Figure 1.

The furnace fuel control comprises a wall member, generally designated by the reference numeral H, adapted to be secured to a furnace by any suitable means (not shown) or to a rigid support positioned in the vicinity of the oil burning furnace. The wall consists of a thick plate 12 having a plurality of grooves formed in the inner surface thereof and which terminate in bores extending from the bottom of said grooves through the plate to the outer surface thereof. The functions of these grooves will be described hereinafter. Another thinner plate I3 is clamped to plate 12 by means of a plurality of screws (not shown) with a sheet of any suitable gasket material is tlierebetween. It is thus seen that the grooves in the plate l2 and the gasket material l4 form the walls of passages adapted to conduct fuel oil from one of the above-mentioned bores to another.

Secured to the wall I l, against the outer face of plate I2 and at the right hand end thereof, as viewed in Figures 1 and 2, is a filtering unit [5. It consists of a casing 16 enclosing a wire mesh filter ii, a fuel inlet tapping I8 and an outlet bore ill. The details of the filter unit form no part of this invention. It may take the form of most any conventional filter.

Mounted on the outer surface of plate 12 adjacent the filter unit, by means of screws 20, is a safety shut-off'valve generally designated by the reference number 2|. As can best be seen in Figure 3, the safety valve comprises a housing 22 having a cone-shaped chamber 23 at its inner end terminating in an axial bore 24. A slot 25' extends from the lower edge of the housing 22 upwardly into the bore 24 and from the outer edge of the housing 22 inwardly to a point spaced from the chamber 23. Extending. vertically through the outer portion of the housing 22 and intersecting the-slot 25 is an elongated opening 26. A diaphragm 21 is positioned between the housing 22 and a ring 28. All three of these elements are secured to the plate l2, with a gasket washer 29 therebetween, by means of the abovementioned screws 28. A valve 38 is secured to the center portion of the diaphragm 21 by means of a threaded stem thereon passing through an aperture in said diaphragm and into threaded engagement with a plunger 3| slidably mounted in the bore 24. The plunger 3| has a diametrical slot 32 therein and an extension of reduced diameter at its outer end. A spring 34 resiliently urges the plunger 3| inwardly to normally seat the valve 35 in a terminal bore of passage 35. The passage 35 establishes communication between the outlet IQ of filter unit l5 and a chamber 38 between the diaphragm 21 of safety valve 2| and plate I2. The outlet from chamber 36 will be described below. Pivoted in the slot 25, on pivot 31, is a bell crank lever 38 having an actuating arm 39 and a power arm 40. The arm 40 extends into the slot 32 for actuation of the plunger 3|.

Vertically slidable in opening 26 is a bar 4| having an aperture 42 therein through which the outer end of arm 39 extends. Slidably mounted on the bar 4| is a manually operable latch member 43 that is best seen in Figure 1. Slots 44 and 45 therein enable the member 43 to slide over thicker washers 48 and between the heads of bolts 4'1 and 48 and the bar 4|. A tension spring 49, anchored to the lower end of member 43 and the bolt 48, normally urges the member 43 upwardly with respect to bar 4| to position the pin 41 against the lower end of slot 44. This provides a lost motion connection between the members 43 and 4| for resetting purposes. A laterally extending arm 50 on the latch member 43 has a transversely bent shoulder portion 5| and a vertical slot 52. A notch 53 in the lower left hand edge of the member 43, as viewed in Figure l, is adapted to cooperate with a bell crank lever latch 56 to hold the valve 30 open, the spring 49 being strongerthan the spring 34. A pivot 54 extends through the upper ends of the legs of a U-shaped arm 55 of the bell crank lever and through slot 52, and is rigidly secured to plate [2. The slot 52 merely enables the latch member to move downwardly over the pivot 54 to reset the latch as described hereinafter. The spring biased lost motion connection between the members 43 and 4| provides a resilient strain release connection between the manually operable latch member 43 and the valve 30 through the bar 4|, lever 38 and plunger 3|, so that the latch member can continue to move after the valve has opened fully, to permit this resetting action. A spring 55a may also be provided between the outer end of arm 55 and a fixed portion of the control, to partially balance the weight of a float to be presently described. The outer end of the other arm 51 of the bell crank lever 56, is pivoted to the upper end of a stem 58 which, in turn, is secured at its lower end to a float 59.

" A trough or drain 68 has a float chamber 6| positioned substantially centrally thereof, a well 62 receiving the lower end of the filter unit l5. and drain surfaces 53 and 64 converging downwardly and sloping toward the back to the top of fioatchamber 5|. The drain B8 is secured to plate I2, with a gasket or cement therebetween, by means of screws (not shown). The drain also has a threaded outlet opening 65 and a bore 66 extending laterally from said opening 55 through the rear wall of the chamber 6| or drain 60 to aline with a terminal bore of a grooved passage 56a in the plate l2. The other terminal boreof passage 65a is positioned above chamber 6|. A bore 61 extends through the bottom portion of the side wall of the float chamber 6| to aline with a terminal bore of an inverted, U- shaped, grooved passage 57a. in plate l2. This passage loops over the passage 66a and connects with outlet through a passage 84, to be described below, and bore 66.

Positioned near the center of the control, above the drain 68 and to the left of the valve 2|, is an accumulator generally designated by the reference numeral 68. As can best be seen in Figure 4 of the drawing, the accumulator comprises a base member 69 having a recessed portion In, a diaphragm H, a piston 12 which is biased by means of a spring 13 toward the base member 69, a guide ring 12a, and an adjustable stop member '54. The accumulator is secured to the plate l2 by means of screws 15 with a gasket 16 therebetween. An opening 11 through the gasket 16 establishes communication between the recess 10 of the accumulator and a terminal bore of a passage 82 (described below) in plate l2. It is thus seen that when the adjustable stop 14 is screwed outwardly, oil under pressure may flow into recess 18 and move the diaphragm and piston 72 outwardly into engagement with the end of stop 14. When fuel pressure is relieved, the spring 13 may then force the piston 12 and diaphragm l toward member 59 and discharge fuel oil from recess 10.

The means for controlling the flow of fuel oil to and from the accumulator 58 comprises a retary control valve 18, best seen in Figure 5. It has three radially extending grooves 19 communicating through concentrically spaced slots 88 in a sleeve-like bearing member 8| with a terminal bore of passage 82. The bearing member extends into the bore and rotates therein. The passage 82 is the one that communicates with chamber 70 of the accumulator 68. The outer endof the grooves 19 are each adapted to successively .pass over the terminal bores of passage 83 and passage 84 (see Figure 1). These terminal bores are spaced apart a distance greater than the width of the grooves 79 and are less than apart. This assures that only one of these terminal bores can be in fluid flow engagement with a groove 79 at a time. The passage 83 leads to a terminal bore communicating with chamber 36 in the safety valve 2|. The passage 84 leads to a terminal bore in alignment with bore. 66 to establish communication with the outlet 65. A boss on the outer surface of the control valve 18 is slotted at 85 to receive a drive plate 86.

The drive plate 86 is driven by a flanged coupling 81 having a slot 88 in a boss thereon, similar to the slot 35. A coil compression spring 89 surrounds the bosses on the members 18 and 81 and the drive plate 85 to hold them in axial alignment and to urge the valve 18 away from the couplmg 81 and into engagement with plate l2. The

7 coupling 81 has a slot in the opposite wall thereof at right angles to the slot 85. This slot is engaged by a tongue 9| of a drive shaft 92. The drive shaft 92 is rotated at a constant speed by means of a gear train (not shown) which in turn is driven by a synchronous motor (not shown) enclosed in the housing 93. The motor housing 93 is mounted on the plate l2 by means of bolts 94 extending through spacing sleeves 95. The distance of the housing 93 from the plate I2 is sufficient to allow a slight amount of play of the ap ease-4;

drive -plate m6 fin the slots 95 and 88, but is sufficiently 'close so as :to keep the spring zse under enough compress'ion to maintain the v-alve T8 in oil seal'ing engagement with 1. the surface of plate l-2. lit will :be noted that the screw-threaded, adjustable abutment '14 is threaded through a lateralprojection 93a extending fremra side "wall of the motor easing 93. Current is @supplied *to the'smotor throughlleads" 92a.

Modification In icthe .modification of the accumulator :shown in Figure'-' 7 ,"thepiston l 'l'zrrha's azlaterally extendingtstem HZb whichslida-bly fits .in an axial bore 96 of a plunger .91. The plunger L9] .sl-idably fits in the epentend-of an --inverted, :cup *shapedmember H98. I,'he member 98 has a .diame-trical slot therethrough,providinga-slot-99 on one. side and a much longer slot 'lllllzon -rthe otherrside. .An axial ,bore .in the closed end --of the vcup-shaped member as receives the 'unthreaded end of a threadedadjustment screw 14a whichis threaded through a fixed support 931). Extending through theslots 99 and I90 is a wedge-shaped plate 194 which, in operation, bears against one end each ofslots 99 and 1.011 and .the end oflplunger-sl, to limit the outward movement of the piston H2. The large end of the plate i! is connected by means of ascrew 1B2 toabimetallicstrip I03. A slot .(not shown) in the bimetaliplate permits the passagetof thescrew 1702 and .allows for longitudinal movement of the screw and plate it! with respect to the bimetallic strip. This 621- ables the side .edges of the plate ill! to properly bearagainst theends .of .slots 99 and 109 and the end of plunger :91. The position of the head of thescrew .102 with respectto the adjoining surface of the bimetallic member, permits, if desired, a slight amount vof movement of the .bimetallic member in one directionand then the other direction before the plate fl)! is moved. One-end of the bimetallic member is secured to a lateral projection 104 on the plate lza, while the center portion of the :jbimetallic member carries a resistance heater I that is adapted to be energized through a room thermostat (not shown) by a source of electrical energy (not shown). The room th'ermostat may be of the 'on-off type or may be of the potentiometer type.

The first would give a two-position operation of the plate H1] while the second would provide a many-position operation thereof.

Operation 'The device is shown in 'its operating position in'Fig-ures 1,72 and 3, that is, with the float in its lowere d'p0sition,'the safety'valve open and the adjustable "abutment'in 'a position to permit the diaphragm'of the accumulator to move outwardly against the bias of "spring .13 under oil supply pressure. As the synchronous motor constantly rotates'the control "valve 78 at a uniform speed, registration of'the end of one of the grooves I?! with a terminal bore 'of passage 83 will permit the flow of fuel through the filter unit l5, passage 35, valve 2|, passage 83, control valve 18, and passage 82 to the chamber Hi of the accumulator 68. This permits the oil under its supply pressure (gravity or pump) to force the diaphragm and the piston against the abutment to accumulate or store a metered charge of the fuel oil. Continued movement of the control valve will first cut off communication between the chamber and the oil supply and then establish communication between the chamber and the fuel outlet 65 leading to the furnace. The discharge large openings.

is .-.-accomplished *by the v groove "l9 -in .ithe control valve registering with the lterminali'borelof rp'assage 84 which leads to the outlet :65 through bore 66. "The provision of three grooves 1:9 in the control valve-causes three .accumulations ian'd discharges for each complete :rotation of :the control valve.

By adjusting .the adjustable abutment or stop outwardly, the rate ofifuel fiowmay be increased inasmuch as a greater' volumeaof fuel :oilwill accumulated every time the accumulator :is :put into fcommunicationiwith the source of fuelesupply. This may be done either manually :by :rotating theiscrewethrea'ded :abutment 1:4 in Figure 4201* automatically by the'croom thermostat causingthe energization of "the resistance heater 211135 to :cause'warpingiof the bimetal intthezdirection of the-arrow shown .inlFi'gurefl.

The control will continue to deliver fuelzata uniform rate at whatever abutment setting is provided. This will :be true even :for the .minimum .lfiow rate in that fuel 'oil does :not have to flow through a small-metering orifice or "passage but by "periodic surges of fuel through relatively This prevents the clogging 0f the fuel passages and, therefore, provides trouble free r-andluniform operation of the furnace.

Figure 4 shows thezabutment T4 in its nc-tiles. position, with the piston and diaphragmyheid against the base member as by the adjustable abutment 14. In this position no :dischargeable fuel can be accumulated or discharged, as the piston 12 and diaphragm "H .cannotmove outwardly under the .oil supply pressure against the bias of spring 13.

Should the flame in the furnace become extinguished, the fuel oil will accumulate in 'the furnace to 'only'that level which will cause th'e fuel oil to back up into the discharge opening 65, through bore 156, through passage "615a and into chamber 61. This will cause the float 159 to be raised to disengage latch arm 55 from the notch '53 in latch member 4'3. As soon .as the latch -member 43 is freed, the spring 34 in the safety valvewill move the valve 3.0- .into seating engagement with the terminal bore of passage 35 and raise the bar 41 and the latch -member 4-3 to their elevated'positions by means rof the bell crank lever .38.

The same safety action would take placeif any one or all of the'units mounted on the platefl started to .leak. For example, if the diaphragm H in the accumulatorshould :spring a leak, the oil escaping around the piston would be caught by the upwardly' and outwardly'inclined surfaces 63 and 64 which would direct the oil into vthe float chamber 61. It is thus seen that if any conditionshould arise that would possibly cause the flooding :of oil over the area of thefurn'ace installation, the safety valve 'would'automatically be tripped by the float mechanism to shut off the flow of fuel.

To resetthe device after the'furnace has been conditioned for operation, the upper end of the latch member 43 is manually moved downwardly to first cause the bell crank lever 38 to open the valve 30, against the bias of spring 34, and then to slide the member with respect to the bar 4|, against the tension of spring 49, to bring shoulder '5l into engagement with arm 51, pivotally connected to the float 59 through stem 58. Further downward movement forces the float to the bottom of chamber 6|. As the float 59 is substantially the same diameter as chamber 6|, fuel oil will be forced outwardly through bore 61 to prime the siphon passage 61a connected to the passage 8-4 adjacent the outlet bore 66. This will cause rapid discharge of the fuel oil from the chamber 6| to the furnace or, if desired, to waste, if the conduit to the furnace is disconnected. Lowering of the arm also brings the arm 55 into a vertical movement path of the bottom edge of notch 53 so that, the releasing of latch member 43, will not cause the lifting of bar 41 to close the valve 30 but engagement of the bottom edge of the notch 53 with the bottom of arm 55.

While the preferred embodiment of this invention has been described above, it is apparent that various modifications may be made therein without departing from the spirit of the invention. Therefore, it is to be understood that the scope of the invention is to be determined not by the above specific disclosures, but by the appended claims.

I claim as my invention: 7

1. A furnace fuel control comprising a substantially vertical wall having inlet and outlet passages formed therein, a valve mounted on said wall for controlling the flow of fuel through said passages, a float chamber secured to said wall under said valve and having upwardly and outwardly inclined drain surfaces, a fuel feeding means mounted on said wall above said drain surfaces and connected to said inlet passage, a passage in said wall providing communication between an upper portion of said chamber and a lower portion of said outlet passage, an inverted U-shaped passage in said wall providing communication between the bottom of said chamber and a lower portion of said outlet passage and having the bridge of said U-shaped passage above said chamber, a float of slightly smaller diameter than said chamber pivotally connected to a bell crank lever having a latch thereon, and manually operable means for opening said valve and forcing said float downwardly in said chamber whereby fuel is forced into said U-shaped passage to prime it and cause the discharge of fuel from said chamber, said manually operable means having a strain release connection with said valve and a laterally extending arm for engaging said bell crank lever and an abutment thereon for engaging said latch only when said float is in its lowered position in said chamber.

2. In a control device for supplying fuel to a furnace and having a vertical wall with inlet and outlet passages therein, the combination comprising fuel feeding means on said wall, a biased closed safety valve mounted on said wall for controlling the flow of fuel through said device, latch means for actuating said valve to its open position against its bias, said latch means having a resilient strain release connection with said valve to permit continued movement thereof beyond the open position of said valve, a float chamber on said wall and having drain surfaces extending laterally from the top thereof and beneath said valve and fuel feeding means, a passage in said wall between said outlet and an upper portion of said chamber, an inverted generally U-shaped passage in said wall having a short leg thereof terminating in a lower portion of said chamber and a longer leg thereof terminating in said outlet at a lower level, a float of slightly smaller width than said chamber and positioned therein, and pivoted latching means connected to said float and engageable with said latch means to hold said valve open when said float is low in said chamber and disengageable from said latch means when said float is high in said chamber to cause closing of said valve.

3. A safety float chamber for a'fuel control device comprising, a chamber, an adjoining wall extending upwardly beside and beyond the upper edge of said chamber for supporting a plurality of fuel control means above said chamber, an inverted generally U-shaped passage formed in said wall with the lower end of one of the legs of said passage terminating in a lower portion of said chamber and the lower end of the other leg terminating in a discharge passage of said device at a lower level than the bottom of said chamber, and another passage formed in said wall extending from said discharge passage to a portion of said chamber.

4. A safety control device comprising, a chamber, an adjoining wall extending upwardly beside and beyond the upper edge of said chamber, a plurality of fuel controlling means mounted on said wall above said chamber, an inverted generally U-shaped passage formed in said wall with the lower end of one of the legs of said passage terminating in a lower portion of said chamber and the lower end of the other leg terminating in a discharge passage of said device at a lower level than the bottom of said chamber, and another passage formed in said wall extending from said discharge passage upwardly between said legs to a top portion of said chamber.

JOSEPH O. THORSHEIM.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 915,780 Malcolm Mar. 23, 1909 1,144,525 Blake June 29, 1915 1,600,507 Marr Sept. 21, 1926 2,174,055 Coleman Sept. 26, 1939 2,219,473 Delancey Oct. 29, 1940 2,242,582 Jencick May 20, 1941 2,317,556 Russel Apr. 27, 1943 2,319,830 Sampsel May 25, 1943 2,323,627 Sherman July 6, 1943 2,330,243 Sampsel Sept. 28, 1943 2,333,602 Van Almelo Nov. 2, 1943 2,349,209 Taylor May 16, 1944 2,355,870 Johnson Aug. 15, 1944 2,367,545 Udale Jan. 16, 1945

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