US2437327A - Process for regulating steam generators and automatic feed systems for such generators - Google Patents

Description

March 9, 1948.

PROCESS FOR REGU FEED SYSTEMS FOR EU I Original Filed Feb. 28, 1941 J LOUMIET ET LATING STEAM G LAVIGNE 2,437

ENERATORS AND AUTOMATIC CH GENERATORS 3 Sheets-She etl fivenlbr Jean loam/1e? 7 Lav/gas fliiorneys March 9, 1948- J. LOUMIET .ET LAVIGNE 2 437,327

PROCESS FOR REGULATING STEAM GENERATORS AND AUTOMATIC FEED SYSTEMS FOR SUCH GENERATORS I Original Filed Feb. 28, 1941 3 Sheets-Sheet 2 Afiornegi J. LOUMIET ET LAVIGNE 2,437,327 PROCESS FOR REGULATING S March 9, 1948.

TEAM GENERATORS AND AUTOMATIC FEED SYSTEMS FOR SUCH GENERATORS Original Filed Feb. 28, 1941 3 Sheets-Sheet 5 Inveniar Jed/7 loam/e7 7 avg/7e Attorneys Patented Mar. 9, i948 PROCESS FOR REGULATING STEAM GEN- ERATORS AND. AUTOMATIC FEED SYS- TEMS FOR SUCH GENERATORS Jean Loumiet et Lavigne, Itabo, Cuba Original application February 28, 1941, Serial No. 380,987. Divided and this application April 8,

1943, Serial No. 482,284.

In Cuba March 9,

9 Claims. (Cl. 122-448) The present invention is a division of my Patent No. 2,377,254 and relates to an apparatus and process for automatically regulating steam generators or boilers and the feed devices there- The system of the present invention comprises basically in establishing, as a first approximation in the regulation of a steam generator, proportional feed supplies of water, fuel and air, in accordance with one of the limiting requirements (maximum or minimum) of efliciency of the generator and in imparting by a complementary regulation, a final adjustment to that original or primary regulation, so as to adapt it at every moment to the exact needs of the steam generator. Imperfection in the functioning of the steam generator is manifested as to the supply of water, by the variations of the water level in the generator and as to the supply of heat (fuel and air) by the variations of steam pressure. These variations in the steam generator are utilized to automatically produce the compensat ing regulations that will rectify the deficiency observed.

The system of the present invention complies with the following requirements: (1) The water supplied at every moment compensates for the consumption of steam taking place. (2) Fuel and air constituting the mediums for producing heat is supplied in relation to the steam consumption or to the water injected in a proportion exactly corresponding at every moment to the operating efiiciency of the steam generator.

The efficiency of the steam generator is variable according as the production of steam for the generator varies. Within the conditions of industrial operation, it decreases slightly as the production increases. The decrease of efilciency becomes more rapidly accelerated than theincrease in-the steam production, and that acceleration is also variable, increasing as saidsteam production increases.

In accordance with the present invention, the original supply of feed water and fuel in a given proportion corresponding to the maximum or minimum of efliciency of the steam generator is obtained by means of a drive motor in the form of a steam engine, electric motor or the like and of feed devices of constant volumetric yield perated from said drive motor at speeds proportional to the speed of said motor. Primary regulation of the feeds to the generator would beobtained by means of the single regulation of the drive motor which drives the water feed pump, the petroleum or other fuel feed pump and variations.

the air pump or blower supplying combustion air. The speed of the drive motor is regulated in such a way that by the primary regulation, the supply of fuel and of air produced corresponds to the exact needs of the boiler, while the supply of water only approximates the real need of the generator. This primary regulation through regulation of the speed of the drive motor is effected in response to variations in the steam pressure in the generator.

The exact requirements of water feed in relation to the feeds of combustion air and fuel are variable in accordance with theelficiency of the steam generator. These exact requirements are met by a secondary or complementary regulation in the rate of feed of the water in relation to the feed of the combustion elements (fuel and air).

This secondary regulation is effected automatically in accordance with the water level in the water drum of the steam generator.

In accordance with the present invention, primary regulation of the drive motor is effected in accordance with variations in the steam pressure alone independently of variations in the water level, and the secondary regulation of the feed water supply is effected in accordance with variations in the water level in the steam generator alone independently of steam pressure Also, the regulations are suspended a short interval after the corresponding regulating steam pressure or water level begins to return towards normal.

As another feature, the complementary regulation of feed water is eifected in a manner to compensate for the decrease in efficiency of the steam generator at a progressively increasing rate as said steam consumption increases after the steam consumption reaches above a predetermined limit.

Various other features of the invention will be apparent from the following particular description and from an inspection of the accompanying drawings, in which Fig. 1 is a schematic view of a form of apparatus in accordance with the present invention for automatically regulating a steam generator and various feed devices for such a generator and for carrying out the process of the present invention;

Fig. 2 is a schematic view of another form of apparatus in accordance with the present invention for automatically regulating a steam generator and feed devices for such a generator and for carrying out a modified form of process of the present invention;

Fig. 3 is a sectional perspective of one of the valves controlling the by-pass between the discharge and inlet of the water feed pump in the apparatus of Fig. 2;

Fig. 4 is another schematic layout showing a modified apparatus in accordance with the present invention for automatically regulating a steam generator and feed devices therefor and for carrying out a modified form of process of the present invention; and

Fig. 5 is a schematic layout showing the secondary regulation of the water feed pump by means of two valves connected in parallel.

Referring to Fig. 1 of the drawings, there is provided a boiler or steam generator C, a drive motor shown in the form of a steam engine Ci having a steam inlet valve V in a supply line T and a water feed pump Ba which is shown of the centrifugal type and which feeds water to the drum of the boiler by a supply line Ta. The water feed pump But is shown driven from the engine Cl by a belt drive.

The engine Ci also drives a fuel pump Bp shown of the reciprocating type operated from the crank shaft of the engine Cl,as shown more fully in Figs. 4, 5 and 6 of the parent Patent 2,377,254. lihis fuel pump Bp is shown delivering fuel to three fuel burners Q ofthe boiler C by means of the fuel supply line b.

The engine Ci also drives a blower Vn, as for example, by a belt drive as shown, to deliver combustion air to the burners Q of the boiler C through an air duct A.

The three boiler feeding devices Ba, 18p and Vn are operated by the same steam engine Cl and the speed of that engine is regulated through variations in the boiler pressure so as'to maintain said pressure constant. For that purpose, the extent of opening of the steam inlet valve V for the engine is controlled from an electric motor m through a speed reduction gearing shown comprising a worm and worm wheel, the worm wheel being aiiixed to a sleeve having a threaded connection with the valve stem, so that rotation of said worm wheel causes axial movement of said stem and corresponding opening and closing movement of the valve. The construction of the valve V and the manner of its operation by the motor m is similar to that shown in Fig. 2 of my Patent 2,377,254.

The motor m is regulated through a compressed air manometer M operating only in accordance with boiler pressure variations to provide a primary regulation of the system operable only in accordance with said variations independently of variations in the water level. This manometer M is similar to that described in my Patent 2,377,254 and shown in Fig. 3 of said patent and operates as indicated in said patent through electrodes 1), k, 'r, 7, Z, and w, connections therefrom to a coil switch box Em and connections 3 and d from said box to the motor m. This manometer M controls the motor m and is operable to suspend the operation of the motor m a short interval after the steam pressure begins to return towards normal, thereby assuring the opening or closing of the valve V to the proper extent to eifect return towards normal without any substantial overrun of said valve.

By means of the primary regulation described, the speed of the drive motor or engine Cl is varied, so that the speeds of all the feeding devices Ba, Bp and Vn are varied in unison; while maintaining the relative rates of feed of said feeding devices substantially constant, thereby maintaining the pressure of the boiler substantially constant.

There is obtained by this first regulation, a supply of. fuel or petroleum corresponding at every moment to the needs of the boiler and a supply of feed water which would exactly represent the supply required by the boiler if operating at that moment under the worst or maximum efiiciency conditions within its operating limits. Since, in real practice, the efficiency of the generator varies, it is necessary by secondary regulationto adjust continuously the supply of feed water from the approximation obtained through primary regulation.

Secondary automatic regulation is effected responsive only to variations in the water level in the boiler alone and independently of steam pressure variations for varying the rate of feed of the water in relation to the feed of the combustion elements, to maintain thereby the water levelin theboiler substantially constant. For that purpose, there is shown in the feed water supply line To. to the boiler, a valve Va, controlled by an electric motor in which in turn is governed by the regulating gauge N. This gauge N is operated in response to the water-level variations in the boiler and is similar to that described in my Patent 2,377,254 and illustrated in Fig. 2 .therein. This gauge N has electrodes 0, b, a and 01 connecting into a coil and switch boxEn which is fed by power lines 5 and 5 and which controls the motor m through connections 5, 6, i and 8. The gauge N functions so that the operation of the electric motor is suspended a short interval after. the water level begins to return towards normal as indicated in the aforesaid patent.

In the construction of Fig. l, the water leaving the feed pump is regulated by regulating the cross-section of the discharge. The water leaving the feed water pump may be regulated by subtracting some of the water or may be regulated in any other manner as will be described.

For every'value of steam consumption, there is a corresponding boiler eiiiciency which is theoretically fixed, and which varies a little, as for example, when the boiler is not clean or when the humidity of the air varies. According to .the steam consumption, there is a corresponding predetermined velocity of the motor that generates all the original feeding rates. It is possible to establish a first regulation by changing the original water rate and adapting it automatically to the efiiciency' variations, such regulation being effected by virtue of the velocity of the motor driving all the feeding mechanisms. Thewater rate regulated in that'manner may correspond exactly to the needs of the boiler with a slight margin in excess, assuming that the actual efficiency of the boiler was the one desired according to its steam consumption. The water rate obtained in this manner will closelyapproximate the required rate for-the boiler, so that the second complementary regulation based on the water level variation in the boiler will have to provide only for the slight difference. Therefore, the maximum effect of this supplementary regulation would be greatly limited, thereby effecting an important advantage.

Figs. 2 and 3 show a processand construction for producing this result. In these drawings, Cl indicates a steam motor or engine for operating the fuel and air pumps (not shown), and also the water feed pump vBa having an inlet Su and an outlet Di. A by-pass connecting this inlet Su and outlet Di is governed by means of valves Va and V'a connected therein in series. The valve Va is governed by virtue of the speed of the engine Ci through a centrifugal governor Re connected to said engine by suitable transmissions (not shown). The vertically movable part of this governor Re carries a rack Cn meshing with a pinion Pi driving a pinion Pi through a belt. This pinion Pi meshes with a second rack Cm connected to the stem of the valve V'a.

As the velocity of the engine Cl increases, the aperture of the by-pass valve Va increases, so that the water rate with respect to the fuel is decreased in accordance with the decrease in efli'ciency of the steam generator C. The valve Va does not begin to decrease the water feed until the boiler efiiciency begins to vary to a substantial extent, i. e., until the boiler efiiciency corresponds to that which the boiler has when its steam consumption is double that of the boiler at its maximum efiiciency. The valve member of the valve Va is constructed to eifect this operation.

The opening of the valve Va must increase with progressive acceleration as the velocity of the engine Cl increases, i. e., the load increases. While the engine speed is increasing, the steam boiler efficiency is decreasing with progressive acceleration. The lower section of the valve member Va is tapered as shown, so that said valve is opened with progressive acceleration as said valve member moves upwardly. In any case, the shape of this valve member is designed to correspond to the efficiency variations of the boiler as the steam production increases.

Valve Va. completes the regulation of the water feeding, and is operated by virtue of the water level variations in the boiler in a manner already described in connection with the construction of Fig. 1.

Figs. 4 and 5 show a similar process and construction, but in connection with a centrifugal feed water pump Ba instead of a reciprocating pump. In the modified construction shown in Fig. 4, the valve Va operated in accordance with water level variations is located in the outlet pipe D2 of the pump Ba behind the valve V'a, but if desired, can be located in said outlet pipe ahead of the valve Va. 7

In Fig. 5, the outlet of the centrifugal pump Ba has two parallel branches merging into the pipe Di and containing the valves V'a. and Va respectively. Although both branches have been shown of equal dimensions, in actual practice it would be desirable to increase the dimensions of the branch regulated by valve V'a in relation tothe branch regulated by valve Va, because the importance of the first regulation is greater than that of the second.

In the form of the invention shown in Figs. 2 and 3, the by-pass valve V'a may be constructed with a cylindrical section and with a lower tapering section as described, and may be arranged so that as long as the speed of the engine does not reach double the speed corresponding to conditions of greatest efficiency of the boiler, the proportion of subtracted or by-passed supply shall be substantially constant and starting from the moment at which said engine speed increases above said limit, said subtracted proportion shall increase with said speed at a greater rate than the speed of the engine and with increasing acceleration as said engine speed rises above said limit. Thisprocess feature of the present invention may be carried out by the constructions of Figs. 2 and 3 described or by any other suitable construction. For example, the valve member of valve Va in Figs. 2 and 3 may be of uniformly tapering dimensions and operated from the engine ball governors through a cam having a section of uniform radius operable to maintain said valve member against movement while the engine is operating below the double speed limit of maximum boiler efficiency and having a section progressively decreasing in radius and operable beyond said engine speed limit to open said valve with progressively increasing acceleration to progressively increase the rate of feed water by-passed or subtracted. The shape of this variable cam section is designed to correspond to the efliciency variations of the boiler as the steam production increases beyond the limit determined by the operation of the engine at twice the speed of maximum efficiency of the boiler.

Instead of controlling the by-pass valve Va by the cam arrangement described, the valve controlled by the cam may be the discharge valve Va of the feed water pump as shown in Fig. 5. In that case, the cam would be constructed with a progressively radially increasing section beyond its radially uniform section, operable to close said valve at a progressively increasing rate to effect decrease in the rate of feed of water into the boiler at the desired progressively decreasing rate. The secondary or final regulation which is effected by means of the water level variations in the boiler would be preferably effected in a pipe connected in parallel with the pipe containing the valve V'a, as shown in Fig. 5.-

I claim:

1. An apparatus for regulating steam boilers of the type provided with a water drum to maintain the water level and the steampressure substantially constant, comprising means for feeding combustion elements to the boiler, means for feeding water to the boiler, a single motor for driving said feeding means, means automatically operable only in accordance with variations in the steam pressure alone and independent of variations in the water level for varying the speed of said drive motor to vary the speed of all of said feeding means in unison, while maintaining the relative rates of feed of said feeding means constant to thereby maintain said pressure substantially constant, means automatically responsive only to variations in the wate level in said boiler alone and independently of steam pressure variations for varying the rate of feed of the water in relation to the feed of the combustion elements, to thereby maintain the water level substantially constant, and means for suspending the operation of said varying means a short interval after the corresponding regulating steam pressure or water level begins to return towards normal.

2. A process for'regulating steam generators of the type provided with a water drum and having as auxiliary units a fuel supply mechanism, a

combustion air supply mechanism and a water feed supply mechanism, which comprises the steps of operating said fuel supply mechanism and said air supply mechanism as a, group in relation to the water feed supply mechanism and at predetermined relative rates to establish a predetermined-proportion between the fuel supply and the air supply, operating all of said mechanisms from a single drive'motor, regulating said drive motor in accordance with the steam pressure variations in the generator to maintain the steam pressure in said generator substantially: constant;

and effecting; supplementary regulation of thewater feed rate inlrelation to therates of fueland air supply in accordance Withthe watenlevel variations in the water drum'to adapt said water'- feed rate to'the actual efficiency of the generator, and to maintain thewater level in'said drum substantially-constant, saidsupplementary 'regula-- tion being efiected-Wi-thout afiectingthe rates-oi fuel and air supply as determined by the regulationof said drive motor and while maintaining said latter rates at said predetermined proportion, both of said regulations being effected slowly'and progressively, and being stopped a slightinterval after the corresponding steam pressure or Water level begins its return movement towards normal;

3, A process for regulating steam-generators of the type provided with a Water drum and having.

as auxiliaryunits a, fuel supply mechanism, acombustion air supply mechanism and a wa'ter feed supply mechanism, whichcomprises the steps of operating said fuel supply mechanism and said air supply mechanism as a group in relation to the Water feed supply mechanismand at predetermined relative rates to establish a" prede-- termined proportion between the fuel supply and the air supply, operating all'of said mechanisms from a single drive motor, regulating" saiddrive motor in accordance With the steam pressure variations in the generator to maintain the steam pressure in said generator substantially constant, and effecting supplementaryregulation ofthe water feed rate in relation to the rates of fuel and air supply in accordance with the Water level-var iations in the Water drum to adapt said water feed rate to the actual efficiency of the generator, and to maintain the Water'level insaid drum'substantially constant, said-supplementary regulation being effected without afiectingsthe rates :01 fuel and air supply as determined by the regulation of said. drive motor and While maintaining said latterrates at said predetermined proportion; the regulation of the motor being effected by varyin'g a valve governing the effective speecl'of sa-id motcr, the motor valveregulatin'g variation being effected automatically in an inverse direction to the steam pressure variation, the supplementary regulation being elfected by means ofa valve governing a by-passbetiveen the outlet and inlet of the water feed mechanism, the regulating varia tion in'said: latter valve being effectedautomat ically by means of the Water level variations in he drumLin the same directions said water level variations, and both of said regulations effected slowly and progressively; and being stopped a slight interval after the corresponding regulating factor begins its returnmovement towards normal.

4. A process for regulating steam =generators comprising simultaneously providing the feed supply of water, fuel and air for a generator by the action of a single drive motor-by'nreans'of apparatus having volumetric outputs substantially proportional to the speed of the drive--motor, in a'proportion corresponding to the exact needs of the generator when operating under conditions representing one of the limits'ofefficiency under practical operating conditions; automatically regulating the speed of the drive motor through pressure variations in the generator alone inde-- pendently of Water level variations and without affecting the relative feed of water, fuel'and air to the generator so'as to'inaintain such pressure substantially constant and adjusting I the supply of: Water in' relation: to the real: needs: of the 8 generator andirelative-to thesfeed'of fuel-and air to the generator througli water level variations inthe generator alone= independently or pressure variations so as to-rnaintain' such -le'vel sub'stan 5 tiaily constant,- the op'erati'on"ofi such regula-- substantiallyconstant, and startingfr'om the moment at which saidspeed increases above-such said proportionshall increase-with saidlimit,

speed :ata greater rate'than the speed, and with acceleration in the-rate'of the increase rising 1 With said speed, the second water regulation-op oration being :effected by level variationswin the generator so as: to maintain such level constant;- 5.- A process for: regulating. steam generators imprising simultaneously providing feed sup plies ofl Water; fuel 'and airfor a-generator by the actions ofwa single: motor'by means of: an

apparatus havingtvolumetric outputs:substantial-- lyvproportional to-the speed of the drive motor; in aproportion corresponding to theexactneeds of the generator when: operating at its :best 'effi ciency conditions; automatically.regulating. the.

speed of". the drive motor through pressure variations-in'rsth'e' generator aloneindependently of water level variations-and withoutuaffecting the relativeefeedlof'water, fuel andt'air to' the generaton-so; as to. maintain such pressure substantially: constant; and subtracting the excess of watenin;

the supply 'thus'aproduoed in relationato the .real needsnfther generatorandrelative to the fuel and,'airz-feedtoxthe generatorrin order-ate adapt.

such" supply exactly: *at? all times to such needs;

said subtraction'; beingheff'ected through water-l level variations in the-generator alone'lindeperr-ldentlyr otpressurewariations so as .to maintain.

suchleve'lusubstantially constant, the. operation ;of such regulation being subject to the direction;

of thevariations of that level, thevcomplementary regui'ationzofj the. supply .of water 1 which is 1 pros in zsaidsprocessrain' responseto the water;

level .vari'ati'on being effected .Lby means of two 1 different: operations; the first 1 one being governed. by; speed, variations lofthe drive "motor: in a such a Way 'thatxit tends ,to' maintain isaidj sup I plyjsubstantially. constant as long; asr-thesspeedjrsaiddrivemotor does not .reach' double therate corresponding to conditions ofli greatest :ef-l fi'ciency of ;theaboiler,:- and startingg' from. that limitiit .tends :to diminishsuch. supp1y:'as. thespeed-50f the drive motorrincreases; attaigreater:

rate ofisuoh decrease thanthespeed increase-rate ofthe drive and with an evergreaterzacceleration, the proportion of theratessas the speed of said-1 drive motorincreases the second. regulation be-1 effectedthnough watenlevel variations in the generator; so :as to maintain such level .substantiallyv constant.

6. Al process for: regulating steam generators comprising simultaneously providing" thei fe'edzlsupplyzofavater; fuel and 'air'ifo'r a l generator by A thesaction: of a single: :driveamotor "by means 0f apparatus having volumetric outputs; substantialis; proportional to the'speed of the drive motor, in a proportion corresponding to the exact needs of the generator when operating under conditions representing one of the limits of efficiency under practical operating conditions; automatically regulating the speed of the drive motor through pressure variations in the generator alone independently of water level variations and Without affecting the relative feed of water, fuel and air to the generator so as to maintain such pressure substantially constant; and adjusting the supply of water in relation to the real needs of the generator and relative to the feed of fuel and air to the generator through water level variations in the generatoralone independently of'pressure variations so as to maintain such level substantially constant, the operation of such regu1ation'being subject to the direction of the variations of that level, the water supply being produced by a centrifugal pump, and in order to adjust the supply of water from such pump to the exact needs of the generator at all times, variation in the volumetric discharge of the pump is produced by regulation of the discharge cross-l section of water pumped toward the generator, such regulation being effected through the differences in the water level in the generator so as to maintain such level substantially constant, both regulations being effected slowly and progressively and being stopped a slight interval after the corresponding steam pressure or water level begins its return movement towards normal.

7. A process for regulating steam generators comprising simultaneously providing the feed supply of water, fuel and air for a generator by the action of a single drive motor by means of apparatus having volumetric outputs substantially proportional to the speed of the drive motor, in a proportion corresponding to the exact needs of the generator when operating under conditions representing one of the limits of efiiciency under practical operating conditions, automatically regulating the speed of the drive motor through pressure variations in the generator alone independently of water level variations and without affecting the relative feed of water, fuel and air to the generator so as to maintain such pressure substantially constant; and adjusting the supply of water in relation to the real needs of the generator and relative to the feed of fuel and air to the generator through water level variations in the generator alone independently of pressure variations so as tomaintain such level substantially constant, the operation of such regulation being subject to the direction of the variations of that level, the water supply being produced by a centrifugal pump, and in order to adjust the water supply from such pump to the exact needs of the boiler at all times, a variation in the volumetric discharge of the pump is produced by regulation of the discharge cross-section of water pumped toward the generator, such regulation being eifected through the differences in the water level in the generator so as to maintain such level substantially constant, two outgoing portions of the water pumped by said pump being varied, such outgoing portions passing through pipes arranged in series; the variations in one of such portions being regulated by the speed variations of the drive motor itself in such a way that as long as such speed does not reach double the speed of conditions of greatest efficiency of the generator, such portions will remain substantially constant, and starting from that point, as the drive speed increases, such portion will diminish at a higher rate of reduction than the rate of speed change of the drive motor and tially constant, both regulations being effected slowly and progressively and being stopped a;

slight interval after the corresponding steam pressure or water level begins its return ment towards normal.

8, A process for regulating steam generators of the type provided with a water drum-andhaving as auxiliary units a fuel supply mechanism, a combustion air supply mechanism and a waterfeed supply mechanism, which comprises thesteps of operating said fuel supply mechanism and said air supply mechanism as "a group in relation to the water feed supply mechanism and at predetermined relative rates to establish a predetermined proportion between the fuel supply and the air supply, operating all of said mechanisms from a single drive motor, regulating said drive motor in accordance with the steam pressure variations in the generator to maintain the steam pressure in said generator substantially constant, and effecting supplementary regulation of the water feed rate in relation to the rates of fuel and air supply in accordance with the water level variations in the water drum to adapt said water feed rate to the actual efficiency of the generator, and to maintain the water level in said drum substantially constant, said supplementary regulation being effected without affecting the rates of fuel and air supply as determined by the regulation of said drive motor and while maintaining said latter rates at said predetermined proportion, the water feed mechanism being in the form of a centrifugal pump, and the regulation of the water pumped being effected by governing a discharge valve on the outlet of said pump leading towards said generator, said latter regulation being effected through variations in the water level in the generator, so as to maintain said level substantially constant, and being stopped a slight interval after the water level begins its return movement towards normal, the other primary regulation being effected slowly and progressively and being stopped a slight interval after the corresponding steam pressure begins its return movement towards normal.

9. A process for regulating steam generators comprising simultaneously providing the feed supply of water, fuel and air for a generator by the action of a single drive motor by means of apparatus having volumetric outputs substantially proportional to the speed of the drive motor, in a proportion corresponding to the exact needs of the generator when operating under conditions representing one of the limits of efllciency under practical operating conditions; automatically regulating the speed of the drive motor through pressure variations in the generator alone independently of water level variations and without affecting the relative feed of water, fuel and air to the generator so as to maintain such pressure substantially constant; and adjusting the supply of water in relation to the real needs of the generator and relative to the feed of fuel and air to the generator through water level variations in the generator alone independently of pressure variations so as to maintain such level substantially constant, the operation '01 such regulation. being subject to -.the direction Y omne variations. of that level,-. the Water .supply being produced by. a centrifugal pump, and in. order-to adjust the. water supply fromsuch pump to .thewexact needs..-of the boiler at all times, a. variationinthe volumetric. dischargeoitheipump is. produced .byregulationof the discharge cross? section .of water .pumped ..toward the generator,

such.- regulationn being efiectede through the differences in the water level in: the generator so. asitoimaintain such. level substantially. constant, two outgoing portions of the. water .pumped by said pumpbeing varied,.. such outgoing portions passingthrough pipes arrangedin. parallel; the. variations in vone. .of such. portions .being, regulatedhythe. speed variations-of the drive motor. itself insucha way that as-longas such speed doesnot reach. double. the speed of. conditions of greatest efficiency of; the generator, such portions will remain substantially constant, and starting fromthat-point, asthe drive :speed increases such portion. will diminish at ahigher rate'of: reducti'onnthan theirate of...speed-.change ofthe drive motor and with continuous acceleration inthe relative proportion-of bothcincreasesns the motor speed increases; the regulation lof the second. a portion. being effectedhy water level. differences in the generator so as-toimaintain. such levelsubqv stantially. constant,- both regulations 1 being effected slowly and progressively and being stoppeda slight intervalafter the corresponding steam: pressure or .water level begins its return movementtowands normal.

JEAN LOUMIETnr LAVIGNE:

REFERENCES CITED.

The following references aremtrecordeinethe file. of "this patent;

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