US2627911A - Fuel control device - Google Patents

Description

Feb 1953 L. v. M cARTY ET AL 2,627,931

FUEL CONTROL DEVICE Filed Dec. 11. 1947 4 Sheets-Sheet 1 Flai T0 MAlN BURNER VVVENTOR. LOURDES M9 CARTY BY RENO I... VICENZI FIG. 2 A-r-remwqv 1953 L. v. MQCARTY ETAL FUEL CONTROL DEVICE 4 Sheets-Sheet 2 Filed Dec. 11, 1947 M-UCMDM OP INVENTOR.

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FUEL CONTROL DEVICE Filed Dec. 11, 1947 4 Sheets-Sheet 5 Z '1 To PlLoT FUEL a 2 25\ u Z2 LlGIHT 5b V V *2 50 l l l 52 W/D/ I E FIG. 9

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LouRoas V. MECARTY Rana L. VICEHZJ ATTORNEY Feb. 10, 1953 L. v. MOCARTY ET AL 2,627,911

FUEL CONTROL DEVICE Filed Dec. ll, 1947 4 Sheets-Sheet 4 NVENTOR. V. MI'CARTY RENO l... VICEN Iii jag MQEM TTOR (15y Patented Feb. 10, 1953 UNITED STATES PATENT OFFICE FUEL CONTROL DEVICE Lourdes' v. McCarty and Reno L. Vic'enzi, Milwau k'e'e, Wisz, assig norsto A P Controls Corporation, a corporation of Wisconsin Application December 11, 1947, Serial No. 791,110

4- Claims.

This invention relates to fluid flow control sys tems and particularly to an improved automatic control system; for gas heaters employing. a pilot burner and a main burner.

Accordingly, an object of this invention is to providle a flow control system which fails safe."

Another object is to provide an automatic unitary fuel control system for a heater employing" a pilot burner and a main humor in which the fuel supply to both burners is cut off when the pilot light goes. out.

A further object is' to' provide a fuel system for a pilot burner and a main" burner wherein the" fuel supply to the main burner is regulated in accordance with the heat demand and the supply to bothburners is interrupted in the absence of av flame at the pilot burner;

Another object is to provide aunitary auto matic fuel control system which may be easily mounted adjacent the burners, thus reducing'the amount" of piping required and allowing more rapid installation. 7

Another object is to provide a fuel flow control system for ahea't'er having apilot burner and a main burner in which fuel flow can not be established until the pilot burner is suificientlyheated to. insure safe operation.

Another object is to provide a fuel flow control system for a burner wherein the control valve is unseated in response to heat at the burner and has associated therewith means for temporarily unseating. the valve for ignition purposes Still another object is to provide a fuel system in which fuel flow to a burner is regulated by a manual valve andia valve which is normally biased to its seated position but which may be unseated in one manual. valve position and retaine'd unseated in other manual valve positions by'me'ans of a device acting in opposition to the biasingmeansin response to heat at the burner. A further object'i's to provide an automatic'fuel control which is contained within a unitarybody carrying the pilot burner'on the body to form a' simple, compact regulator.

A further object isto provide a fuel control system-wherein flow to the burner is regulated'by an automatic valve, in accordance with heat demand,.- by a manually operated valve and by a valve which seats'in the absence of 'he'at at a pilot burnerr Another object is to provide a never urner which prevents combustion at the air intake:

A further object is to-pr'ovi'da burner which combustion can take place only at the burner tip under normal conditions" and in which the name will return to the-tip afteri-l'rl' ials lileliibltvl'i-batik towards the fuelsource by some abnormal: eon-= ditiofi.

Other and further objects Wll-lb' p6i nted-6fifi 0'1 will beapparent in thespecification and claims In the drawings:

Fig. 1 is a diagrammatic schematic showingof; the embodiment of the invention-shown'in Figs .--2 to 12;

Fig. 2 is aplan View of a production ffibodi ment of the invention as viewed from 2- 2 Fig. l;

F g. 3 is an elevation asviewed from in Fig. 4; Y

Fig. 4 is another elevation of the device as vie'weclfrom 4-4" in Fig. 3

Fig. 5 is a cross section taken along brokeii-lih 5 5 in Fig. 6;

Fig; 6 is a cross section along line 6-"Sinl igr35 Fig. 'Tis' a cross section ofthepilot burner taken along l -Tin Fig. 3;

Figs. 8--10 are'fragmentary cross sections o'f 'dif ferent positions of the manual control vaiveas seen in Fig; 5; I

Fig. 11 is an elevation as viev'vedfrom l l f-l on Fig. 3 but hasthe cover plate removed; and

Fig. 12' is a fragmentary cross section aion'g" line I 2 l2 in Fig. 6.

In order to simplifyunderstanding of the op erating principles and the construction of the" embodiment of our invention as shown in Fi'g's'i 2 through 12,. reference will first be had to-t e schematic'showing of Fig. 1 which'show's'an' l'1-"" tomatic control system" for the fuel" supply toa"- heater having a pilot burner and ammo buner'. Fuel flows into the regulator throuhg conduit F0. past control valve [2", whichis biased byspiing" Hi to its seated position, into" the manual valve chamber It. In the position shown,- manuallycontrolled-valve mauows fuel fiowthrou-gh 'coii duit Zlto pilot'bur'ne'r 28 since cam 22' on valve I8 bears against depending follower 24" to lift valve l2 to its unseated position. Placed next to'pilot burner 20' is a hollow cylinder 26 which- 'is connected tothe-inside-of diaphragmtll by means of the small bore in plug 21 in connecting conduit 28 and contains charcoal 29 and an adsorbed inert gas which, when heated, will increase the pressure inside snap diaphragm 30. The cylinder 25 is charged below atmospheric pressure so the diaphragm will be flexed inwardly. In the position shown, pilot burner 20 is lighted and the pressure within the hermetically sealed system comprising cylinder 26, conduit 28, and diaphragm 3%] has caused the diaphragm to snap outwardly to strike crank arm 32. The crank is pivoted at 34 and carries follower 24 and valve I2 on its other arm 36 to unseat the valve when the crank is rotated in a clockwise direction by the diaphragm action and to lift the valve when cam 22 strikes follower 24.

Further clockwise rotation of manual valve I3 from the position in Fig. 1 will move cam 22 away from follower 24 so that valve I2 is retained in the open position by diaphragm 3!] alone. In this position, should the pilot light go out for any reason, the pressure within cylinder 26 and diaphragm 33 will decrease until the diaphragm snaps to its inner position and allows spring I4 to close valve I2, thus shutting off the supply of fuel to chamber I6 and the pilot burner.

Still further clockwise rotation of valve I8 will expose conduit 38 to allow fuel to enter chamber 40 as well as pilot burner 20. Flow from chamber 40 to the main burner through conduit 42 is regulated by regulating valve 44 which in turn is controlled by a spring-loaded diaphragm 45 in response to heat demands of the heated medium. Connected to the inner side of diaphragm 46 is a conventional wet-charged bulb 48 which has a normal pressure below atmospheric. One end of shaft 54 is connected to diaphragm 46 and its other end carries lever 56 which is pivoted at 'I to open and close valve 44 in response to movement of diaphragm 43. Compression spring 50 seats against adjustable yoke 52 and against lever 56 and acts on the diaphragm in a direction to aid an increase of pressure within the diaphragm. The pressure within bulb 48 and diaphragm 46 decreases with a decrease in temperature. Thus when the temperature drops below the value determined by the position of adjusting screw 60. which determines the degree of compression of spring 50 by varying the position of yoke 52 about its pivot 63, valve 44 will open to allow fuel flow to the main burner and will remain open until the demand for heat has been satisfied at which time the pressure in bulb 48 snaps diaphragm 46 to close regulating valve 44.

When manual valve I8 is in position to allow flow to both the pilot and main burners, valve I2 controls flow to both burners. When the pilot flame is extinguished the pressure within cylinder 26 and diaphragm 38 decreases and snaps the diaphragm to permit spring I4 to seat valve I2 and positively cut off fuel flow to both burners, thus insuring a fail safe control system. A further feature of this arrangement comprises automatic cut off of the fuel if the manual valve is rotated to this position before the pilot burner and its associated thermal element are not adequately heated. This insures complete safety of operation in every phase of control.

In referring to Figs. 2 through 10, parts similar to those shown in schematic Fig. 1 are referenced by the same numerals to simplify comparison.

Figs. 2 through 4 of the exterior of the commercial product show fuel entrance l0, pilot burner 20, conduit 42 to the main burner (not shown), thermal element 26 adjacent pilot burner 28, and a hollow flexible cable 41 leading to the Wet-charged bulb (not shown). The position of manually controlled valve I8 is determined by knob I9 and the adjustment of spring 50 which determines the temperature at which the heated medium will be maintained is controlled by movement of handle 5|, as will appear more fully hereinafter.

As may be seen most clearly in Figs. 5 through 7, the fuel enters the regulator at I I] and flows past control valve I2 which is biased by spring I4 to a seated position. Spring I4 is retained within threaded nut I5 by means of snap ring 11 so removal of nut l5 will remove the valve assembly. Mounted below valve I2 is a conical portion l3 which rides in a cooperating hole in crank arm 36 which is pivoted at 34. At the end of crank arm 35 is depending follower 24 which rides on cam 22 on manual valve I8. Valve I8 is tapered and biased by spring 25 to tightly fit Within the cooperating taper of valve chamber I6 and is rotated by means of knob I9.

As shown in Fig. 5, cam 22 has lifted valve I2 oif its seat to allow fuel flow to pilot burner 20 through conduit 2I. As may be seen in Fig. 6, diaphragm 30 is not flexed outwardly, indicating the carbon in cylinder 26 has not been heated by pilot burner 20 to increase the pressure. Thus the position shown in Figs. 5 and 6 is the position for lighting the pilot burner and is denoted on knob I9 as Light. After the pilot burner has been lighted, the pressure inside diaphragm 39 will increase to snap the diaphragm outwardly and retain valve I2 unseated withoutthe aid of the cam action. In this condition fuel flow to pilot burner 20 will be through the conduits 2I, 23 past the adjustable metering valve 3I (Fig. '7) which may have a filter screen associated therewith. As may be seen in Figs. 2 and 7 the air for the pilot burner is taken into burner pipe 20 through holes 33 which are shielded by a co-axial tight-fitting sleeve 35 having an annular opening 31 facing the burner tip. It has been found that this burner construction does not permit combustion to take place at the air intake. Thus the pilot flame may exist only at the burner tip. The reason for this is believed to be similar in principle to the miner's lamp where the temperature is kept below the fuel ignition temperature.

Should it be desired to operate only the pilot burner, the valve I8 is rotated in a clockwise direction, after the pilot has been lighted, to the Pilot position shown in Fig. 8. In this position the cam 22 no longer underlies follower 24 and valve I2 is free to close in the event the pressure drops within diaphragm 30 due to failure of the pilot light. Further rotation of manual valve I8 to the On position (Fig. 9) will expose conduit 38 to chamber 40 and to the main burner as well as conduit 2I to the pilot burner. Here again there is no obstruction to hinder the action of the valve I2 when the pilot flame goes Fuel flow to the main burner through conduit I 42 is regulated by means of valve 44 as may be seen most clearly in Figs. 5, 6, 11 and 12. The

action. of. .valve 44 is regulated by pressure. variations. within. the. wetechargedv bulb, (not. shown) and diaphragm 46. in. accordance with the heat demand. of' the heated medium, Fixed to the central portion. of diaphragm 4.5is shaft 55 which carries at its, end a. composite; lever 56. Lever 55 is pivotedon axis. X.--X. by. means of pins 51, threaded into thecasing. and projecting through cooperating holes. in lever plate 55. Valve as is mounted on, the. lower end of, lever 55 and is adapted to ield against spring 54 to avoid damage to the valve face and to insure full seating. Seat 5| forspring 55' is notched at 53 to engage lugs 55 on lever 55 and holds lever 55 in contact with adjusting nut 62 on the end of shaft 54'. The other end of spring 50 is seated on cupped annulus 58 engaging notches 59, 59 in the free end of yoke 52 which is movable about pivot 63 in response to inward or outward movement of screw 59 as controlled by knob 6|. If knob 61 is rotated in a clockwise direction, as viewed in Fig. 4, screw 60 is moved inwardly to move yoke 52 about pivot 63 to increase the compression force of spring 50, thus aiding the action of pressure within the diaphragm 45 and decreasing the temperature at which the heated medium will be maintained. Conversely, counterclockwise rotation will increase the temperature at which the heated medium will be maintained.

For most satisfactory operation it is preferred that thermal element 26 be charged with charcoal or other adsorbing material and an adsorbed gas inert with respect to the adsorbent material as more fully set forth in abandoned application Serial No. 790,272 of Lourdes V. McCarty assigned to the applicants assignee. It has been found that argon produces more accurate characteristic operating curves over long periods and wider temperature ranges than have heretofore been attained.

It is also preferred that the diaphragms 30, d5 be of the snap-acting variety to prevent flashback although other diaphragms could be used. Of the snap-acting types, it is preferred that the construction forming the subject matter of copending application Serial No. 1,678 of Lourdes V. McCarty assigned to the applicants assignee, be used since the force required throughout the length of the throw is more uniform and may be adjusted within very fine limits to give the desired characteristic.

The automatic regulator shown and described herein is particularly adapted for use in conjunction with hot water heating systems but it will be evident that the regulator and heater may be used in other ways and to heat other mediums. While the regulator shown is adapted to control gaseous fuel, the system could be modified slightly to handle liquid fuel. Equivalent or modified parts may be substituted in whole or in part without departing from the spirit of the invention. Accordingly we do not wish to be limited except by the scope of the claims.

We claim:

1. A fuel flow control system comprising, a body having a chamber, an inlet to said chamber, a pilot outlet from said chamber, a burner outlet from said chamber, a manually operated valve for controlling flow from said chamber through one or both of said outlets, a safety valve in said inlet, means biasing said safety valve to its closed position, a bell crank pivotally mounted in said chamber with one end adapted to lift said safety valve from its seat, means acting on the other end of said bell crank in response to heat of a pilot flame to. hold; said safety valve open, and am m an m nted on the manual valveinsald chamber for acting on said one: endofsaid crank to lift the safety valve when said manual valve is directing flow through said pilot outlet only.

2. A fuel. flow control system comprising; a body having a chamber, aninletto: said chamber, a' pilot. outlet from said chamber, a. burner. outlet from said chamber, a. manually operated; valve for controlling flow from. saidehamberthrough said pilot outletor both of said ontlets,a.safety valve in said inlet, meansbiasing said safety valve to its closed position, a pivotally mounted bell crank having one end adapted to lift said safety valve from its seat, means operatively interposed between the manually operated valve and the control valve and operable when said manual valve is positioned to direct flow through said pilot outlet only to actuate said bell crank to lift the safety valve, and means acting on said bell crank in response to heat of a pilot flame to hold the safety valve open.

3. In a fuel control, a casing having an inlet, a pilot burner outlet and a main burner outlet, a chamber in said casing communicating with said inlet and said outlets, a safety valve in said inlet for regulating fuel flow to the chamber, means biasing said valve to its closed position, a bell crank adapted to lift said safety valve from its seat, means acting on one end of said bell crank in response to heat of a pilot flame to hold the safety valve open in opposition to said biasing means, control valve means for regulating fuel flow from the chamber to the outlets, said control valve means including a manually operable handle exterior of the casing and a valve in the chamber positionable to direct fuel to the pilot outlet only in one position, to both outlets in a second position and to cut off flow to both outlets in a third position, and reset means operatively associated with and dependent in its operations upon the setting of the control valve means and operable to act on the other end of said bell crank to open said safety valve when the control valve means is in said one position and being inoperable when said control valve means is in said second position, said reset means being operable only by means of said control valve means.

4. A fuel flow control system comprising, a body having a chamber, an inlet to said chamber, a pilot outlet and a burner outlet from said chamber, a manually operated valve in said chamber and having off, light, pilot, and on positions, said manual valve closing both of said outlets in said off position, permitting flow to both outlets in said on position, and preventing flow through said burner outlet while permitting flow to said pilot-outlet in said light and said pilot positions, a safety valve in said inlet, means biasing said safety valve to its seated position, a bell crank pivotally mounted in said chamber with one end adapted to lift said safety valve from its seat, means responsive to the heat of a pilot flame to actuate the other end of said crank to hold said safety valve from its seat, and cam means operable on said one end when said manual valve is in said light position to unseat said safety valve, said cam means being inoperable in said pilot and said on positions.

LOURDES V. McCARTY. RENO L. VICENZI.

(References on following page) 7 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Brombacher May 29, 1928 Kibe May 7, 1929 Grayson July 16, 1935 Spencer May 12, 1936 Mantz June 30, 1936 Dillman June 29, 1937 Cermr Aug. 6, 1940 Number Number Name Date Ray Sept. 23, 1941 Ray Mar. 2, 1943 Jackson et a1 May 18, 1943 Ray July 18, 1944 Jackson July 4, 1944 Wantz Mar. 27, 1945 Ray June 17, 1947 Mueller July 26, 1949 FOREIGN PATENTS Country Date Great Britain Aug. 24, 1933

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