US1695472A - Furnace-controlling apparatus - Google Patents

Description

De.1s,192s.* 1,695,472

E. ROUCKA y FURNACE CONTROLLING APPARATUS Filed Aug. 23, 1927 "l 1-?. BY

. ATTORNEYS Patented D ec. 18, 1928.

ERICH RO'UKA, OF BLANQKO, CZECHOSLOVAKIA.

* rUnnAcE-conzrnqumc n'rrnnn'rus.

- Application mea Aukust as, 1927,' serial No.

This invention relates to apparatus 4for controlling furnaces, particularly furnaces'asso-4 ciated with steam boilers, invention bein to provide novel'and im- 5 proved means or automatically controlling the drafts of the furnace and the supply of fuel to the furnace. Another object is to providefsuch apparatus including novel and improved means for controlling the drafts andthe supply of fuel in accordance with thefdemand or load on the furnace, for example the demand for steam on a steam boiler associatedwiththe furnace.

A further object is 1K3 provide s'uch appal5 ratus including means for automatically controlling the drafts and means for automa-tically controlling the supply of fuel, in `combinatio with means actuated in accordance With the load or demand on the furnace which in turn regulates the actuation of the draft control means and the `fuel supply control means, so that the drf'ft and the supply of fuel are controlled in accordance with the loadpn the furnace.

Otherobj ects are to provide in such appa-A ratus a normally balanced means for controlling the draft in thefurnace, a normally balanced means for controlling the sup-ply of fuel to the furnace, and 'means actuated in accordance with the load on the-furnace for varying the balance of the first twormentioned means so thatboth the draft and the supply of .f l areregulated in accordance Wit-hlthe loadueoh the furnace; to provide in such ap- 35. `paratus a pair of movab c members both ac tuated by a Apilot motor. controlled in accordance with the demand on the funace and one `of which varies the actuation ofthe means for 'controlling the draft, and the other of 40 whichvaries the actuation of the means for controlling the suppl "of v.fuel; l'to provide such apparatus inclu ing lever systems for'. respectively controlling the draft and the supply of fuel, the leverage of said systems beingvaried by-means actuated in accordance with the load onthe furnace;- and to obtain other advantagegsand results as will bev brought out by the following description Referring tothe accompanying; drawings,

in which corresponding and like. parts are designated throughout the'several views of the same reference characters,

Figure 1 is a schematic illustration of a one object of the 214,930. and in Germany September 1, 1926.

furnacecontrolling apparatus embodying my invention, and V Figure 2'is Va fragmentary schematic view of a modified form of apparatus for Vcontrolling the supply'of fuel. y i

The apparatus embodying my invention includes certain features describedand claimed in my copendingl application Serial No.A

24,629, filed April 20, 1925,'but in that appli2 cation there is no means for controlling the supply of fuel. y

Specifically describing the illustrated embodiment of the present invention, the reference, character A designates a steam boiler in which steamy is' generated by a furnace B' which includes an/ automatic Stoker C. The draft through the furnace is regulated b a damper D which is automatically contro led by mechanism generally designated E. The su ply of fuel by the stoker C is automatically controlled 'by mechanism generally designated F, and both of the mechanisms E and F are regulated .by mechanism G actuated in accordance with tLhe load on the fur nace, or in the present instance thel demand for steam on the boiler A. In this connection, it shouldbe understood that any condition variable in accordance with the demand on the furnace may be utilized as the. actuating forcefor the mechanism G, for example temperature, steam pressure, rate of owof steam from the boiler, etc. 4

The mechanism E includes a jiuid pressure operated servo-motor 10 including a cylinfA "der and piston, the latter of which is operatively Connected to the vdamper D so that reciprocatlon'of the piston willoscillate the damper to open and closed positions. The flow of compressed air or the like to and from -the motor 10 is .controlled by a governor valve 11 of thecylinder and piston type, the piston of which is connected to. one end of a lever 12 fulcrumed intermediate'its `ends upon a movable roller 13 interposed between the lever anda fixed support 14. Said end of the lever is also connected to the diaphragm 15 ofa device 16 responsive to differences' in preslre of the combust1on gases 1n the furnace at the pointsl? and 1,8, said device 16 being cnnect'ed at opposite sides of the diaphragm to the furnace by pipes 19. The otherend of the lever is connected by a bow 20 and a tenl 4sion spring 21 to a fixed support 22. The

tension of the spring 21 is adjustable in any suitable manner by a set screw 23. With this construction, it will be understood that the tension of the spring 21 may be adjusted to balance the pressures exerted on the diaphragm so that-the apparatus willbe 1n balanced condition with a predetermined draft pressure in the furnace; and when the draft pressures vary the change in the difference in peire at opposite sides of the diaphragm 15 will cause an oscillation of the las lever 12 which in turn will actuate the governor valve 11\and set the motor 10 in motion, whereby 4the damper D is adjustedto increase or decrease the draft, depending on the origi nal variation. The apparatusV E therefore automatically tends to maintain a Aconstant draft pressure in the furnace.

The fuel supply mechanism F includes an electric motor 7 which actuates the automatic stoker C, the current to said motor being controlled by a rheostat 24 actuated by a servomotor 25 similar to the motor 10, the flow of compressed air to and from which is-controlled by a governor valve 26 similar to the valve 11. The piston of the valve 26 is con# nected to one end of a lever 27 fulcrumed intermediate its ends on a movable roller '28 interposed between the lever and a fixed support 29. The motor 7 drives a blower fan or the like 30 the outlet of which is connected by a pipe 31 to a pressure responsive device 32 at one side of the diaphragm 33 the other side of which is exposed to the atmosphere. The diaphragm 33 is connected to the same end of the lever 29 as the piston ofthe valve 26, and the other end of said lever is connect# ed by a bow 34 `and a tension spring 35 to a fixed support 36. The tension of the spring 35-is` adjustable by suitable means 37. With this construction it will be observed that the blower fan 30 constantly exerts pressure on the diaphragm 33, which pressure varies in accordance with the supply of fuel by the stoker C for the reason that both the fan and the stoker are actuated by the same motor 7. The .difference in pressure at opposite sides of the diaphragm 33 may be initially balanced by"setting the spring 35, so that the mechanism will be in balanced condition when a predetermined rate of fuel supply obtains, and the mechanism will therefore tend to maintain a. uniform rate of fuel supply.

The rate of fuel supply must vary in accordance with the demand or load onl the furnace, more fuel being required when the load increases and less fuel when the load decreases. Accordingly, means is provided for regulating the actuation of the mechanism F in accordance with the demand on the furnace, in the present instance the withdrawother side of which is exposed Vto the atmos- .phere and carries a fulcrum pedestal 41 upon which bears a knife edge 42 on a lever 43 pivoted 'at one end adjacent the knife edge42 as at 44 to a fixed support. Thepiston of a fluid pressure governor valve 45, like the valves 11 and 26, is connected to the lever 43 and controls the flow of fluid pressure to and from a piston and cylinder pilot motor 46, the piston rod `47 of which projects from opposite ends of the cylinder and has one end provided With a lateral arm 48 operatively connected to the roller 28 so as to move said roller longitudinally of the lever l27 upon longitudinal movement of the piston rod. The pressure exerted by the steam from the boiler A on the diaphragm 40 is balanced by a countcrweight 49, so that when a predetermined steam pressure obtains in the boiler A the lever 43 is at rest andthe mechanism G is in balanced condition. When the steam pressure increases or decrea sft lever 43 is moved in one direction or the ot er and actnates the governor valve so that the piston rod 47 is moved in one direction or the other, whereby the balance between the spring 35 and the difference in pressure at opposite sides of the ment of the piston of the motor 25 which aci y tuates the rheostat 24 to vary the current supplied to the motor l7 The speed of the motor is thereby varied and accordingly also is the supply of fuel by the stoker C. Obviously the pressure created by the fan 30 is also varied. It will be clear that an increase in the steam lpressure in theboiler A due to a. slack in the. demand, will cause a reduction in the rati` of fuel feed, while a decrease in thesteam pressure due to increased demand on the boiler will cause an increase in the rate of fuel `supply. The rate of fuel supply will continue to be varied until the pressure created by the fan 30 again balances the tension of thc spring 35. The piston rod 47 is connected by a flexible cable 50 and a tensionspring 51 to thelever 43 so that movement-of the piston diaphragm 33 will be disturbed. Such dislll() rod tends to return the lever to normal. or neuy tral position.- In other words, when the lever 43 is moved upwardly by an increase in steam pressure, the piston rod 47 moves in the direction of the arrow so as to increase the tension of the spring 51, thereby tending to return the lever 43, and upon a decrease in steam pressure a reverse action takes place. It will be understood from the foregoing that the supply-of fuel is cont-rolled in accordance with the demand on the furnace.

Itis also desirable that the draft be controlled in accordance with the demand on the furnace, and accordingly the piston rod 47 is provided with a second arm 52 which is op` eratively connected to the roller 13 so that movement of the piston rod varies the balance of the lever 12, an increase in the demand f construct-ion,

on the furnace causing a movement of the roller 13 so ,f as to increase the draft, while a decrease 'n the load on the furnace causes actuation ofthe mechanism E to reduce the draft. l

A modified form of a paratus for controlling the fuel supply is s own in Figure 2 ofl the drawings, and includes the electric motor 53 .t /e current supply for which is controlled by ,a rheostat, as shown in Figure 1 of the rawings. The motor is preferably'disposed with its shaft vertical and has secured to said shaft a disk 54 against which bears awheel 55 mounted upon a `,countershaft 56 to rotate therewith but slidable longitudinally thereof.

The wheel 55`is actuated longitudinally of the shaft 56 by a bifurcated arm 57 secured to the pist-on' rod 47 of the motor 46. The shaft 56 has a worm which meshes with a worm gear 58 on a second countershaft 59, which is in turn geared by chain and sprocket gearing 60 to the automatic st ker C. With his will be o servedthat .Ae speed of actuation of the stolzer C will vary 'in accordance with the relative position of the wheel 55 and the disk54, the reater thev distance ofthe point of 4contact o the -wheel 55 with the disk 54 from the center of the' disk, the greater being-the speed of actuation 1 lof the stoker. This point of contactS icontrolled by movement of the piston'rod'j47 which as above described is controlled in accordance with the demand onthe furnace.`

Obviously the piston rod 47 ma F by merely adding other arms like 48 and 52.

. Havingthus described the. invention, what v Iclaimis: 1. Furnace controlling a paratus, c0m-' rising means for varying t e flow of comustion gases in a furnace, means responslvc to variations in the pressure of said/combustion gases, means cooperating with said re-l sponsive means to produce a normallyv balanced relation, a movable meinber for varying said relation, means actuated bycooperacause actuation of the. first-mentioned means,

tion of the two llast-mentioned means, upon departures from said balanced relation to a fuel supplying means, means ,automatically responsive" to supplying meansoperates, means cooperating with the last-mentioned means to produce a normally balanced' relation, a second movable member for varying the last-mentioned relation, means actuated by cooperation of said means responsive to the rate of fuel supply and said means producin a balanced Jrelation to vary actuation of sai fuel supply. .ing means, a common means for lboth of saidl Amovable members, a means responsive to a condition variable 'in accordance' withthe heat demand on the furnace .for 4controlling actuation of said common' means. v i

be con-` nectedfto additional mechanisms li e E and the rate at 'which said fuel mova le members, agovernor tuating nace, means to cooperate withsaid sensitive l means to roduce a balanced relation, a movable mem er for varying the coo eration of said two last-mentloned means or ivarylng -the flow of combustion gases, means for supplying fuel to the furnace, means for varying the speed of said means for supplying fuel to vary said supply, a second movable member to cooperate with the lastmentioned means so as to regulate the variations in said speed, the position `of said member having a predetermined adjustable relation to the magnitude of the fuel feed, an auxiliar .pilot 'motor for actuating both of said Inova le members, a. governor for controlling said pilot motor, a

movable means sensitive to a condition variiable with the heat demand to actuate said auxiliaryA motor for cooperating with the last-mentioned movable sensitive means.

3.` A combustion controllingfs stem, comprising means for varying the ow ofl conibustion' gases in a furnace, va servo-motor for governor, and a return drive actuated lby said\ actuating said' means, a governor for controlling said motor, a 'movable means recooperate withA said responsive means to pro duce a normally balanced relation, a movable member for varyingl the cooperation of the two last-mentioned means. so as to vary the .flow of combustion gases, means for supplying fuel 'to the furnace, vmeans for varying` the rate of operation o f said means for suplying fuel, a second servo-motor for actuatmg the last-mentioned means, a governor for controlling said second servo-motor, means actuated according to the rate of fuel supply to produce a force'whichfhas a certain relation to the rate of -fuel supply, a movable means responsivevto said force, means to cooperate with the last-mentioned responslve means for balancingsaid force, a second movv l able member for varying'the relation of the two last-mentioned means, a common auxiliary lot-motor for actuatin or controlling said motor, movable means sensitive to a condition variable with the heat demand to actuate said governor; and a return; drive 4actuated by said auxiliary motor for cooperating withv the last-mentioned movable sensitive-means.'

4. A combustion controlling system', comi prising means forwarying the flow of combust1on.l gases 1n a furnace, a servomotorfor actuating'sard means, a governor for. con

vtrolling said motor, movable means responboth of said sponsive to lvariations inthe pressure 'of the v ,combustlon gases'in the furnace, means to vlil() lao Vlast-mentioned means so as to control the variations in said rate of operation ofthe fuel supplying means, a common auxiliary pilot motor for actuating both of said movable members, a governor for controlling said motor, a movable means sensitive to a condition variable with the heat demand to actuate said governor, and a return drive actuated by said auxiliary motor for cooperating with the last-mentioned movable sensitive means.

5. A. combustion controlling system, comprising means for varying the flow of combustion gases in a furnace, a pilot motor for actuating said means, a governor forfcontrolling said motor, movable means responsive to variations in tbe pressure of said'combustion gases in the furnace, means including a lever system to cooperate with said responsive means to produce a normally balanced relation, a'movable member for varying the relation of the two last-mentioned means so as to vary the flow of combustion gases, means for supplying fuel to the furnace, means for varying the rate of operation of said fuel supplying means, a second pilot motor for actuating the last-mentioned means, a governor for controlling said second pilot motor, means actuated according to the rate of fuel supply, a movable 'means responsive to varia'- tions in the actuation of the last-mentioned means for producing a force which has a certain relation to the rate of fuelsupply, means to cooperate with the last-mentioned responsive means for balancing said force, a second movable member for varying the relation of the two last-mentioned means, a common auxiliary pilot motor for actuating both of said movable members, a governor for controlling said motor, movablel mea-ns sensitive to a condition variable with the heat demand to` actuate said governor, and a return drive actuated by said auxiliary motor for cooperating with the last-mentioned movable sensitive means. I

6. A combustion controlling system, comprising means for varying the flow of combustion gasesA in a furnace, aservo-motor for actuating said means, a governor for controlling said motor, movable means responsive to variations in the pressure of said combustion gases in the furnace, means including a lever system to cooperate with said responsive means to produce a normally balanced condition, a movable member for varying thc leverage of said lever system to vary the relation ofthe two last-mentioned means, means for supplying fuel to the furnace, means for varying the rate of operation of said fuel supplying means, a second movable member to cooperate with the last-mentioned means to control the variations in said rate of operation, a common auxiliary pilotmotor for actuating botli of said movable members, a governor for controlling said motor, movable means sensitive to a condition variable With the heat demand to actuate said governor, and a return drive adapted tol be actuated by said auxiliary motor forcooperating with the last-mentioned movable sensitive means.

7. A combustion controlling system, comprising means for varying the flow of combustion gases in a furnace, a servo-motor for actuating said means, a governor for controlling said motor, movable means responsive to variations in the pressure of said combustion gases in the furnace, means including .a lever system to cooperate with said responsive means to produce a normally balanced condition, a movable member for varying the leverage of said lever system to vary the relation of the two last-mentioned means, means for supplying fuel to the furnace, means for varying the rate of operation` of said fuel supplying means, a second servo-motor for actuating the last-mentioned means, a governor for controlling said second servo-motor, means adapted to be actuated according to the rate offuel supply, a movable means responsive to .variations in the actuation of the lastmentioned means for producing a force which has a certain relation to the rate of fuel supply, means to cooperate with the last-mentioned responsive means for balancing said force, a second movable member for varying the relation of the two last-mentioned means, a common auxiliary pilot motor for actuating both of said movable members, a governor for controlling said motor, movable means sensitive to a condition variable with the heat demand to actuate said governor, and a return drive actuated by said auxiliary motor for cooperating with the last-mentioned movable sensitive means.

8. Furnace controlling apparatus, comprisingmeans for varying the flow of combustion gases in a furnace, means responsive to variations in the pressure of said combustion gases, means cooperating with said responsive means to produce a normally balanced relation, a movable member for varying said relation, means actuated by cooperation of the two last-mentioned means upon departures from said balanced relation to cause actuation of the first-mentioned means, a fuel supplying means, means automatically responsive to the rate at rwhich said fuel supplying means operates, means including a lever system cooperating with the last-mentioned means to produce a normally balanced of. said fuel supplying means, a common 'relatioma second movable member forvarymeans for actuating both of said movable ing the leverage of said lever system to vary members, and means responsive to a condition 10 the last-mentionel relation,A means actuated variable in accordance with the heat demand 5 by cooperation of said means responsive to 0n the furnace for controlling actuation of the rate of fuel supply and said means 'prosaid common means. dueing a balanced relation to vary actuation ERICH ROUKA.

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