US1713839A - Automatic combustion-controlling device - Google Patents

Description

May 21, 1929.

4 Shets-Sheet. 1

Filed Nov. 4, 1924 May 21, 1929. w. H. LARKIN, JR

AUTOMATIC COMBUSTION CONTROLLING DEVICE Filed Nov. 4, 1924 I72 denier: 142a.

4 Sheetfiheet 2 /fiornya.

y 21, 1929. w. H. LARKIN, JR 1. 13.839 4 AUTOMATIC COMBUSTION CONTROLLING DEVICE Filed Nov. 4, 1924 4 Sheets-Sheet 5' y 21, 1929. w. H; LARKIN, JR 1,713,839

AUTOMATIC COMBUSTION CONTROLLING DEVICE Filed Nov. 4, 1924 4 Sheets-Sheet 4 May 221%, i929 a P '1 ii We: r; n in but iii ti at l his WILLIAM H.

LAEKIN, JR, OF EASSAIG, NEVT JEBSEY, A$SIGNOB OF ONE-HALF TO ERNEST L. W'UDLLEY, OF PROVIDENCE, RHODE ISLAND.

AUTOMATIC GSMBUEiTION-CDNTROLLING DEVICE.

Application filed November This invention relates to an improved automatic control-device for regulating combustion in steam-boiler furnaces.

The principal object of the invention s to provide an apparatus of the type specified which is extremely sensitive and instantly responsive to variations in steam pressure and steam flow to regulate combustion in accordance with requirements with minimum consumption of fuel.

A particular object of the invention is to provide a combustioncontrolling device which is influenced by the factors of both steam pressure and steam flow to respond more quickly to changing conditions of steam generation and steam consumption, whereby to prevent loss of pressure in the boiler without increasing combustion to a wasteful degree.

Another object of the invention is to provide a control-device which may be employed to regulate the fuel supply, the induced and iiorced draft in the furnace and other controls if required.

Further objects of the improvement are set forth in the following specification which describes a preferred embodiment of the invention as illustrated in the accompanying drawings. In the drawings:

Fig. 1 is a general view of a steam-boiler furnace oi. conventional type showing my improved control-device as applied to use therewith for regulating the fuel supply from an automatic stoker and also for controllng the forced and induced draft therein; i

Fig. 2 is a vertical sectional view of the control-device Fig. 3 a fragmentary sectional view illustrating a modified form of one of the control-clements of the apparatus;

Fig. 4 is a plan view of the control-device shown. with its casing in section to illustrate the operating parts therein;

Fig. 5 is an enlarged detailed view of the diil'erential-wcight compcheating-mechanism which connects two of the control-elements of the apparatus;

Fig. 6 is a plan view of the same;

Fig. 7 a still further enlarged view showing a detail of the construction of the differential-Weight mechanism;

8 an enlarged longitudinal sectional View of the main steam pipe leading from the boiler, illustrating a usual form of 4, 1924. Serial No. 747,802.

Pitot tube which may be used as the steam flow element of the control;

Fig. 9 is a cross-sectional View of the main steam pipe showing the Pitot tube; and

Fig. 1.0 is a longitudinal sectional view of the main steam pipe showing an orifice plate applied thereto as an alternative form of flow-control element.

Referring to the drawings, my improved control-device comprises a plurality of coordinated mechanisms which will first be described in detail as separate units. The several units of the apparatus are preterablyv enclosed in a casing C herein illustrated as a rectangular box supported from a flanged base and provided on the front with an opening or door (Z.

1l[0t07'.The motor or actuator M which furnishes the power for operating the fun nace controls may be of any suitable type, and I have herein illustrated a fluid-pressure cylinder 2 containing a sliding piston which may be operated by compressed air, oil or steam-pressure taken direct from the boiler. As shown in Fig. 2 the cylinder 2 is lined with a bushing 8, preferably constructed of brass or bronze, within which is the sliding piston 4. The'piston-rod slides through a suitable gland or stui'iing box 6 at the top of the cylinder 2 and is braced by a bearing on an arm 7 extending from the upper wall of the casing Q. As indicated in Fig. 1, the upper end of the piston-rod 5 projects through an opening in the top of the casing C and is connected to the various controls of the furnace, to be later described, by means of chains or cords. In some cases the piston-rod may be extended downwardly through a gland at the bottom of the cylinder 2 to project below the easing C "for connection with controls at a lower level, when so required.

fit one side of the cylinder 2 is a slidevalve 10 for controlling the admission of pressure through two ports 12 and 13 in the valve-casing or steam-chest 14, the ports communicating with the opposite ends of the cylinder through ducts l5 and 16. It will be noted that the valve-casing 14 is shown in l as being offset to the front of the cylinder 2, but to render the showing of Fig. 1 clearer I have here illustrated it as being in the vertical plane on which the section-is taken through the axis of the cylinder.

1 rockable lever The lever 25 has a pintube or cylinder 40 fits.

sure in the cylinder.

communicate respectively with the ports 12 and '13. The valve is controlled by a valve-gear V which operates on the well known principle of the trick valve employcd quite generally with mechanisms used for reversing marine engines by steam power. The valve-rod 21 extends upwardly through a stuflingbox QQ-and at its upper end carries a forked joint 23 by means of which it is pivotally connected at 24 to a and-slot connection'27 with a slidable piston 26 to be later described. At its opposite end the lever is pivotally connected at 29 toa reach-rod 30 which is joined at its upper end to a second rockable lever 3 The lever 32 is fulcrumed at 33 on a fixed bearing 34 extending, from the side of the easing,- G. -The long arm of the lever 82 has a fork at its end formed with slots 35 which are engaged by a cross pin 36 projecting from the sides ofa collar 37 fast on the piston-rod 5. The reach-rod 30 is preferably made in two parts which are connected by aturnbuckle 31 to provide for adjusting the-length of said rod. It will be obvious that through the above arrangement of the valve-gear V the valve 10 is controlled in position from the sliding action of the piston 26 under the further control of the piston-rod 5 in the cylinder 2. Static, steam pressure cylimleva-The piston 26 is operated under direct steam presr' sure in a relatively small cylinder. 40 constructed in the form of a tube. The pressure cylinder v4O is supported vertically from a step or pedestal 41 secured to the base of the casing C and having a bore into which the The pedestal 41 is provided with a duct or opening 42 on its side into which is fitted a suitable nipple connecting with the steam supply pipe robe later described. 7 througl'i the lower end of the cylinder or tube 40 in line with the duct 42 admits steam pressure into the cylinder from the nipple or steam pipe 43.

The piston 26 is enlarged at its lower end and bored to adapt it to enclose the steam cylinder or tube 40 so that the pressure in said cylinder will act to raise the piston in the manner as hereinafter more fully described. At the lower end of the piston 26 is a flange 44 which supports a cylindrical weight 45 surrounding the piston and acting as a comiterbalance against the steam pres- The weight45 is held from turning on the piston 26' by means of ascre'w 46, and the weight and piston are prevented from turning by means of a guidescrew 47 inserted through the side of the casing C with its end engaging a slot or A small hole drilled pressure device P above described consti- V tutesthe static pressure control-element of the apparatus and is connected by a differontialmechanism to the steam flow control" element of the apparatus which is next described.

Steam flow contraZ-eZeme'nt. The steam flow control-clement of the apparatus con, sists of a slidable piston controlled in position under pressure from opposite sides of the Pitot tube or orifice plate in the main steam pipe leading from the boiler. The pressure acts through the medium of a quantity. of mercury in a mercury pot F, as next. described. The mercury pot F consists of a cylindrical casing 50 mounted on a bracket or hearing 51 fastened to the interior of the casing C by means of screws 53. The casing 50 encloses a cylinder 54 in which is the piston 55 having upper and lower pistonrods 56 and '57 sliding through stufiing boxes 58 the upper rod 56 being further supported from a bearing 59 carried by the arm 7 which braces the piston-rod 5. The piston 55 is normally maintained in raised position, as illustrated in Fig. 2, by the mercury m in the pot 50, it being noted that the interior of the pot communicates with the cylinder 54 through openings 60 at the bottom thereof. Steamis admitted to the top of the mercury pot F under static pres sure through a nipple 61 entering its side and connected with a steam supply pipe to be later described. Steam. under velocity pressure is admitted to the top of the cylinder 54, in which the piston 55 slides, through a port 62 into which is threaded a pipe 63 connected by a pipe 64 leading directly from the Pitot tube to be later described.

, Piston comzvterwee'glzt. For counterweighting the piston 55 and its attached parts I preferably employ a bell-crank lever- 70 fulcrumed at't'l on a bearing extending from the side of the casing C. The short arm of the bell-crank 70 carries a pendant rod 72 having means at its lower end for supporting a plurality of weights 73 which may be subtracted or added to as required. The-long arm of the bell-cranlrTO terminates in a fork having slots 74 engaged by a crosspin '75 driven through theupper piston rod 56. As the bell-crank 70 is rocked under the rise and fall of the piston 55 theleverage of its shorter arm will be varied. to adjust the effect of the weights 73 in proportion as required to counterbalancethe piston and its parts under varying operating conditions; this action being more fully described hereinafter. The lower piston-rod 57 is conneoted to the steampressure operated piston through a differential compensating mechanism or governor constructed and arranged as next described.

Di/ferential g0oera0r.-Betweenthe static steam-pressure control-member or piston 20 and the velocity steam-pressure control-ole ment or piston is a differential mechanism which constitutes the main gOV8l.1'llI1 element of the apparatus. One form or this governor is illustrated in Fig. 2 and shown in detail in Figs. 5 to 7. As here illustrated the upper end of the piston 26, which is operated from the steam pressure cylinder 40, is reduced in diameter to receive a flanged cup fastened thereto by a. cross-pin 81. The lower end of the piston-rod 57, operated from the piston 55, is also reduced in diameter to receive a similarly-shaped inverted cup 82 held thereon by a cross-pin Suspended from the'-"upper cup 82 is a differential weight which is constituted by a series of semicircular weightlinks 85 joined together by a novel arrangement of mechanism as next (lGSCllbGt. As shown in Figs. 5 and (i, the weights 85 consist of halfrings which are pivoted together by means of wire pins 86 passing through hingedugs S7 and bent around at their ends to hold them in place. Each half-ring or weightlink 85 is provided with a forwardly pro jecting lug 88 on its inner edge adjacent the joint which it makes with its complementary link, see the enlarged sectional view, Fig. 7. The lugs 88 on each two opposite link-sections or half-rings are adapted toengage on opposite sides of a wire-staple 89 which has its ends secured loosely in the opposite complementary links. The upper link of the series is fastened to the bottom of the upper cup 82 by means of screws 90, see Fig. 5, and the distance between the cups is proportioned that the lower link of the series will normally be suspended just above the bottom cup 80, see Fig. 2. All of the links will therefor be normally supported from the upper cup due to the fact that the play or swivelingaction at their hinges is limited by the dogging action of the lugs 88 on the cross wires or staples 89. In other words, the lugs 88 on each pair of links 85 pinch against the staple 89 and prevent the links from being extended in the axial direction of the chainor helix formed by the series of connected links, see Figs. 6 and 7. lVhen, however, the lower cup 80 rises in relation to the upper cup 82 the individual links are successively picked up and the weight of each added to the lower cup while the remaining links hang suspended from the upper cup, the functioning of this mechanism being explained more fully in connection with the operation of the complete apparatus.

Alternative form of ah'fiereniial gov-- ernor.A modified form of the differential governing-device is illustrated in Fig. 3 of the drawings, in which a single cylindrical weight is carried by the piston 20 and normally held submerged in a bath of mercury contained in a jar 96 suspended from the lower pistorrrod 57 of the piston 55. The rising of the pistion 2G, or the dropping of the piston alters the degree of submergence of the weight 95 in the mercury in and thus varies its operative effect on the piston 26 in accordance with requirements. For this purpose the piston-rod 57 has an en larged extension 9'? at its lower end carrying an inverted cup 98, to which is attached a cylindrical casing 99. The lower part of this casing 99 is formed with a flange 100, to which is attached the mercury jar 96by means of an inturned flange 101 at its top held by screws 102.

The upper part of the jar 96 is formed with a saucer-like rim 103 which provides an enlarged basin to add volume to the body of mercury contained in the jar. This construction provides that as the weight 95 rises out of the mercury in there will be a minimum change in the level of the fluid. E tending upwardly from the bottom of the jar 96 above the level of the mercury contained therein is a cylindrical sleeve 10 1 having a central bore through which the piston 26 slides with a loose fit. The upper end of the piston 26 is reduced in diameter to adapt it to slide into an axial bore 1.05 in the pistonrod 57, it being noted that holes 107 are drilled through the rod 57 into its bore to allow the escape of air so that the movement of the piston 26 therein will not be resisted. The weight 95 is attached to the piston 26 by means of a flanged collar or cup 108. As shown in Fig. 3, the weight is fastened to t is flange by means of screws 109. and the collar or cup 108 is secured to the piston 26 by a cross-pin 110. lit will be seen that the weight 95 is free to slide up and down within the mercury jar 98 without contact with the sides thereof or with the bushing 1041. and the casing 99 is formed with openings 112 to permit the egress of air so as not to resist the movement of the weight. The function of this moditied form of differential compensating-device is the same as that previously described in which the connected weights are employed, its method of operation being hereinafter more fully explained.

The pressure comreozfe'ons.-For the static pressure and velocity head control of the piston 55 I may employ a usual type of Pitot tube device as illustrated in Figs. 8 and 9. In these views the main steam pipe 115 leading from the boiler is shown in section with the arrow a indicating the direction of {low therethrough. A nipple is inserted through the side of the pipe with a hand-valve 119 connecting it to a steam pipe 117. Spaced-away fromthe nip- .ple 116 is a second nipple having an'up- V for'measuring the velocity head or flow of the steam. 9n the nipple 118 is a hand-valvo 121 which connects with a steam pipe 122. Referring now to Figs. 1 and 2, the pipe 117 for the static pressure leads through the top of the casing C down the side thereof, and is provided with a T 128 which connects with the nipple 61 leading into the top of the mercury pot l to supply pressure through the mercury to the under side of the piston 55. The steam pipe 117is continued downwardly as indicated at 124, to supply static pressure to the cylinder- P. a suitable fitting 125 at its lower end being connected to the nipple 43 leading through the peoestal 41 to the bottom of the cylinder 40. The steam pipe 117, 124 is continued horizontally across the bottom of the casing G and connected to the motor M by means of suitable fittings 126, 127 and 128, the latter nipple leading into the steam-chest 14 on the side of the motor cylinder 2. lhe connections above described supply static pressure to the several steam cylinders; while the steam pipe 122 leads down through the top of the casing C and by means of an elbow 1230 con. necting with the nipple enters the duct 62 in the cylinder 50, thus providing a velocity head acting against the top ofthe piston v55.

It will be understood that the steam connections may be varied as desired and a modified fornr of steam flow device" employed in place of the Pitot tube. For example, in Fig. 10 I have illustrated a mod ern type of orifice plate, sometimes called a .Mexican'hat. lVith this arrangement the main steam pipe 115 leading from the boiler is formed in two flanged sections 135, 136, with'the orifice plate 137 held between theflanges thereof. lVith this construction a nipple 138 connects through valve 139 and pipe 140 with the velocity side of mercury pot F and a second nipple 141 valve 142 and pipe 143 connects with the static side of the mercury pot.

Combustion c0mir0Za-ln the general view in Fig. 1 isshown an arrangement of my improved apparatus for regulating combustion in a conventional type of steam boiler furnace. It is to he understood, however, that thisshowing is by way of example only, as the apparatus is adapted for use with other types of furnaces and with different methods ofcontrol. In Fig. 1, B designates the boiler havingits furnace fed by an automatic stoker S which isoperated by a steam engine E taking pressure from the boiler through connections not herein illustrated and controlled by a valve 145. The valve lever 146 is weighted to normally hold it closed and is adapted to be opened by means of a cordfor chain 147 passing over a pulley 14 i A larger pulley 149 fast with the pulley148 has a chain l50 leading therefrom over a third pulley 151 and thence down to the main operating motor piston-rod 5 to which it is connected at 152.

The over fire or induced draft in the combustion chamber of the furnaceis controlled by means of damper D in the main flue H. The damper D is moved from a lever 155 carrying a weight 156 at one end which tends toholdit closed. Connected to the opposite end of the lever 155is a cord or chain 157 which forms a continuation of the chain 150 fastened to the piston-rod 5. Through this arrangement the. dropping of the piston 4' will cause its rod 5 to open the lamper D.

In Fig. 1 I have also illustrated the furnace as provided with a forced draft under the lire which is fed from a suitable blower or fan indicated at J as being operated from a steam turbine K. Pressure is supplied to the turbine motor K through asteam pipe 160 leading from the boiler and inwhich is a control valve 161. 7 The valve 161 is operated from a weight-lever 162, the weight tending to maintain the valve closed. Fastoned to the outer end of the lever 162 is a cord or chain 163 leading up over apulley 164. The pulley 164 is fast wit-ha larger pulley 165 which has a chain leading thereover and connected to the chain 150 fastened tothe piston-rod 5. It will thus be seen that both the overfire and under-fire drafts and the fuel feed are controlled from the movement of'the piston 5, and other controls may be added when required. In place of the steam engines employed to 0p erate the StOlKGl S and the forced draft fan J, I may employ electric motors having suitable switches and rheostats for regulating the current through the operation of controls from my improved apparatus In other cases whereliquid fuel. is used in the. furnace, the supply to the burner nozzles may be controlled byvalves operated from the apparatus through suitable connection with the piston-rel The method of operation of the complete device is as followsj 1h ethod 0/ O ePat'z Om In Fig. 2 the several units of the apparatus are illustrated in convenient position to render the showing clear without regard for their normal cooperative relation when the device is in use. The individual elements of the mechanism may be proportioned and adjusted in ical condition. For example, assuming that the boiler is to operate at say 124- pounds gauge pressure, and that the constant weight 4 .5 on the piston 26 is proportioned to resist 120 pounds pressure in the cylinder 40, then with the boiler at anything over 120 pounds the weight will be lifted ofi' its seat on the pedestal 41. Assuming further, that each of the hall circular weights 85 of the differential weight-mechanism XV is proportioned to resist a hall pound of pressure in the cylinder 40, then with a static pressure in the boiler of 12st pounds the pressure supplied :trom the main steam pipe 115 through pipes 117 and 124 to bottom of cylinder will cause the piston. 26 to raise the weight until it is balanced. by eight of the onehalli pound weights 85; it being understood that the piston 26 rises the cup on its upper end successively picks up the ditferential weights to increase the operative force of the weight 45. As the piston 26 rises it lifts the long arm of lever 25 of the valve-gear V and slides the valve 10 to open the lower port 18 in the steam-chest 14:, thus admitting steam to the bottom 01 the cylinder 2 beneath the piston 41-. The pressure on the under side oi? piston 4L raises the latter to slide its rod upwardly and by means of the chains connected to the rod operates the control for the furnace as follows:

Referring now to Fig. 1, as the piston-rod 5 slides upwardly the chain 150 is paid out over the pulleys 151, 165 and 1419 with the following result: First, the flue-damper D is causedto be rocked into partly closed position under the action of its weight 156; second, the valve-lever 146 is lowered to reduce the pressure to the engine E operating the automatic-stoker S; and third the lever ].(32 is also lowered to reduce the pressure supplied through valve 161 to tin-brine K which operates the forced draft tan or blower J.

It may be assumed that with the controls in position as shown in Fig. 1 the boiler is operating under normal pressure with the constant weight .115 and. added differential weights 85 in the cup 80 balancing the pounds pressure in the cylinder &O. To maintain this condition, however, the piston 4i must be balanced and this is accomplished through. the action of the valve-near V. As the piston ti rises its red 5 lifts the long arm of lever 32, he short arm of which, operating through the reach-rod 30, depresses the fulcrum of lever 25, and in this way the valve 10 is moved back into position to maintain the piston l balanced in the position it has previously assumed. Should the pressure in the be" continue to rise, however, the continued upward movement of the piston 26 will maintain the valve 10 open to admit steam to the under slde of piston 4c to slide its rod 5 upwardly until all of the controls, i. e., the fine damper D and valves and 161, are entirely closed.

Considering" the boiler as operating at normal, should the pressure therein start to drop, for instance, from lowered combustion in the furnace, the di'llerential weights 85 acting in conjunction with the constant Weight 45 will cause the piston 26 to descend under the lessened pressure in the cylinder 40. This action will unseat the valve 10 to admit steam at the top of cylinder 2 so that the pressure will carry the piston 1 downwardly, thus causing its rod 5 to pull the chain to open the controls to increase combustion in the furnace.

The above explanation of the operation of the device takes into consideration only its action under control of static pressure, but indicates the general method of functioning; of the control actuator or motor M and its valve-regulating means as constituted by the weight-controlled or differentially balanced pressure piston 26. Combustion control de- Vices operated under static pressure have heretofore been employed in the art, but have not been found satisfactory and sutiicient for the purpose intended because of their sluggish action. Slight changes in the condition or the fire may not be immediately reflected in the boiler pressure and hence the controls will not be operated promptly enough to increase combustion before the pressure has fallen to a considerable extent. Moreover, a sudden overload on the boiler, as resulting from the starting of an additional unit of machinery, will not immediately reduce the static pressure in the boiler and hence the drain may be continued until it is too late to check the tall by opening the controls to increase combustion. these and other reasons it is therefore desirable to provide means for actuating the con trols under fluctuations in the steam flow or velocity head, which means will be more quickly responsive to an increase in the load on the boiler. he present invention embraces such an improved control. of combustion under changes in steam flow or velocity head as effected by certain elements of the apparatus above described, the novel method of operation of which is as follows:

Gpemtioa under velocity head control.- Assuming that the boiler is running along at normal gauge pressure of 124- pounds with the parts of the control apparatus in balanced relation as above described, if a new unit of machinery started a heavy load is placed on the engine with a sudden heavy demand for steam from the boiler. The creased demand for steam from the boiler will instantly cause an increasedveloci yhead in the steam main, which acting through the Pitot tube device or aperture plate and connections to inouce pressure on the piston 55 For of piston will therefore overcome its balance andforce the piston downward, causing its rod 57 to progressively deposit the differential weights 85 on the cup 80 surmounting the piston 26; Thepiston 26 will thus be overbalanced and forced downwardly against the pressure in the cylinder 40, and during its motion it vill shift the lever to slide the valve 10 to admit pressure at.

the top of the motor cylinder 2. Consequently, the piston 4 will be caused to descend to slide its rod 5'to pull the connecting chain 150, see Fig. 1, whereby to open the damper D and also the control- valves 145 and 161 for the stolrer engine E and blower turbine K. Through this action comby the decreasing bustion in the furnace is immediately increased until pressure in the boiler is raised to take care of the extra load. As the pre sure, in the boiler increases the piston 25 will be raised again, and acting through the lever 25 it will operate the valve- 4- V to balance the piston 4 in proper position to once more setthe controls for normal com bustionin the furnace without waste of fuel,

As the piston descends it'roclrs the bell v crank lever connected to its rod 56 to ra se the counterweight-s 73, and as the bellcrank turns on lts pivot 71 the leverage of its short arm diminishes to reduce the oper- The bell-crank f 70 and its weights Z3 are so proportioned that ative force of the weights.

as the differential weights 85 are dropped from piston 55 into the lower cup on the piston 26 the loss of weight on the pieten 55 is compensated, or substantially so,

' on the bell-cranltTO. during its rocking mothe static andflow tion. In this way the piston 55 and its, connected parts are at all times maintained under an approximatebalance so that it will be more sensitive to thecontrol of pressure from the Pitottube.

' It has been explained that theleads from sidesof the aperture plate 137 in'the main steampipe 115, see 10, control the pressure on thepiston 55 in the mercury pot F in til-.QSSIHQ manner to obtain the same result with the Pilot tube shown in Figsvl and 8; It i also to be understood thatthe modified. formof differential-weight device shown in Fl 3, which is the preferred form of this element, functions in substantially the samemanner as the linked weights illustrated at'W in- Fig. 2. When the effect of the weights I t3 piston 55 is forced down in the mercury pot F the mercury jar 96 will be lowered to lessen the degree of submergence of the cylindrical weight on the lower piston 26. The operative'force of weight95 on piston 26 is therefore augmented to cause the piston to be overbalanced against .t-he pressure e'flicient in its control so that conditions of combustion in the furnace are not permltted to vary between wide extremes; In other words,the dev ce operates automatically to quirements of the load on the boiler or the steam flow therefrom, but not toan extent to cause waste of'fuel by allowing the pressure to get too low and then increasing combustion to an abnormal degree. p While I have described and illustrated my invention as embodied in apparatus ofa certain structure it is to be understood that changes may be made in the form and arrangement of its parts beyond the modifications herein suggested, and such alterations in design and construction would fall within the scope and spirit of the invention as defined by the appended claims.

I claim: r

1. In a combustion-controlling device for steam boiler furnaces, the comblnation of a pressure operated motor for adjusting the furnace controls, a balanced piston operative under static pressure from the boiler on'one sideand velocity pressure on the opposite side, a differential governor operated from the balanced piston, and means operated by the movement of said piston and controlled by the action of the governor to control'the pressure in the motor to regulate its adjustment of the furnace controls. 7

2. In adevice of the type specified, the combination with the controls of a steam boiler furnace,'of a motor foroperating said controls, a piston displaceable by steam pres sure from the boiler under velocity head,. a differential governor" connected to said piston, and means actuated by said piston under the control of the governor to regulate the action of the motorto operate the controls in accordance with the flucuations in steam flow from the boiler.

3. In a 'deviceof the type'specified, the

in the cylinder 40, whereby the piston will It will also be seen increase combustion'in accordance with recombination of a motor for operating the controls, of a steam boiler furnace, means to energize the motor to open and close the controls, a balanced piston displaceable by pressure under velocity head from the boiler, a differential governor connected to said piston, and means operated by the piston under the control of the governor to regulate the application of energy to the motor.

l. In a device of the type specified, the combination or a piston for operating the controls of a steam boiler furnace, means for supplying pressure to the piston to move it in opposite directions to open and close the controls, a second balanced piston, a differential governor between the first and second pistons, means to supply pressure under velocity head from the boiler to the balanced piston, and means operated by the displace ment of the balanced piston a d acting through the differential governor to regu' latethe action of the cont-roloperating piston.

In a device of the type specified, the combination of a piston for operating the controls of a stem boiler furnace, means for applying pressure on opposite sides of the piston, a valve for controlling the direction. of application of pressure on the piston, a second balanced piston, a differential gravity operated governor connected to the balanced piston, means for applying pressure under velocity head from the boilerto displace the balanced piston, and means operated by the movement of the balanced piston and controlled by the governor to regulate the action of the valve for the control-operating piston.

6. In a device of the type specified, the combination of a piston for operating the controls of a steam boiler furnace, a va ve for admitting pressure to opposite sides oi said piston, a second piston operated by static prcr-isure from the boiler to shift the valve to admit pressure to the first piston to operate the furnace controls, a valve-gear opcratcd from the first piston to reset the valve to hold said piston in balanced position, a third piston operated by steam pressure under velocity, head from the boiler, and means operated from the third piston to regulatc the movement of the second piston which controls the valve for the first piston.

7. In a device of the type specified, the combination of a piston for operating the controls of a steam boiler furnace, a valve for admitting pressure to opposite sides of piston, a second piston operated by tic pressure from the boiler to shift the valve to admit pressure to the first piston to operate the furnace controls, a valve-gear operated from the first piston to reset the valve to hold said piston in balanced position, a third piston operated by steam pressure under velocity head from the boiler,

and diiferential mechanism operated from the third piston to resist the movement of the second piston after the latter has shifted the valve for the first piston to a predetermined extent.

8. In a device of the type specified, the combination of a fluid pressure piston for operating the controls of a steam boiler furnace, a valve tor admitting pressure to opposits sides of said piston, a second piston operated under static pressure from the boiler to shift the valve for the first piston, a counterweight for resisting the movement of the second piston, a third piston operated by pressure under velocity head from the boiler, and a diiiercntial governor-mechanism acting to automatically increase and decrease the force of the Weight for resisting the movement of the second piston in accordance with fluctuations in steam flow from the boiler.

9. in a device of the type specified, the combination of a motor for shitting the furnace controls, beans for controlling the direction of action of the motor, a piston operated by static pressure from the boiler to operate the motor-controlling means, a

aveight acting against said piston, a balanced piston operated by pressure under velocity head from the boiler, and differential mechanism operated by the movement of the balanced piston to increase and decrease the Weight on the static pressure piston Whereby to regulate its control of the motor under fluctuations in steam flow from the boiler.

10. In a device of the type specified, the combination of a fluid pressure cylinder, a piston in said cylinder, means for connecting said piston to shift the furnace controls, a valve for admitting pressure to opposite sides oi said piston, a second piston operated by static pressure from the boiler, a counterweight on the static piston, means connectingthe static piston to operate the controlvalve for the first piston, a third piston operated by pro re under velocity head from the boiler, and a diiforential-governor operated from the third piston to apply a variable degree of We on the static-pis ton to regulate the action'o't the latter in proportion to the increased steam flow from the boiler. i

11. In a device of the type specified, the combination of a motor for shifting the furnace controls, means for controlling the direction of action oi said motor, a" piston operated by static pressure from the boiler to actuate the 1notoiJ'-controiling means, a second piston operated by pressure from the boiler under velocity head, a mercury jar carried by the second piston to adapt it to be raised and lowered by the movement of said piston, and a Weight on the first piston submerged in the mercury in the jar carried by the second piston whereby movement of the second piston regulates the degree of submergence of said weight to vary its operative force on the first piston.

12. In a device of the type specified, the combination of a motor torshittingthe turnace controls, means for controlling the direction of action of said motor, a piston operated by static pressure from the boiler to shift the motor-controlling" means, a secondpiston operated by pressure under velocityhead from the boiler, a mercury suspended from the second piston and providcd with a sleeve through which the first piston slides, and a cylindrical weight sup' from the boiler under velocity head, a mercury jar suspended from'the balanced piston and provided with an opening in its bottom through which the static piston slides, and a cylindrical weight surrounding the static piston and carried thereby to adapt it to be submerged to a variable extent in the mercury in the j ar carried bythe balanced piston in accordance with the relative displacement of said pistons.

14. In a device of the type specified, the combination with the furnace controls, of a motorfor operating said controls, means for controlling the operation of .saidmotor, a mercury pot, a piston maintained suspended by the. mercury in said pot, means for admitting statlc pressure from'the boiler to hold the piston suspended, meansftor admitting pressure under velocity head from the boiler to act against theopposite side of the piston, and means operated from the movement of said piston to regulate the action of the motor-controlling means in cordance with variations in'the flow of steam from the boiler.

15'. In a combustion-controlling; device for steam boiler furnaces, the combination with the furnace'co'ntrols, of a fluid pressure cylinder, a piston. slldable 1n said cylinder and connected to operate the furnace eontrols, a valve in the cylinder for controlling the admission of pressure to opposite sides of the piston, a lever for shifting said valve, a second lever operated from the pistonan-d connected to thefirst lever to shift the fulcrum of the latter't-o re-seat the valve,

a second piston 'operatedby static pressure .eury to control the position of the the chamber on one side of the piston, and

means for admitting steam under velocity pressure to the chamber on the opposite side of the piston :Wher by to operate the latter in the manner and tor the purpose substantially as described.

17. In a combustion-controlling device for steam boiler furnaces, the combinationot a cylinder containing a heavy fiuid,;a piston suspended in the fluid in the cylinder, means for admitting steam under static pressure to the cylinder on one side of the piston, and means for admitting steam under velocity pressure to the cylinder on the opposite side of the piston.

18, In a combustion controlling device for steam boiler "urnaces, the combination of a cylinder containing mercury, a piston slid able in said cylinder, and means for supplying'steam under velocity head to the in terior of the cylinder to act against themerpiston in the cylinder.

19. In a combustion-controlling devicetor steam boiler furnaces, the combination of a cylinder, a piston slidable in the cylinder. a chamber communicating With the cylinder, a supply of heavy fluid in the chamber for maintaining the piston suspended in the cylinder, means for admitting steam under velocity pressure to the chamber to act through thefiuid on one side of the piston, and means for admitting steam under static pressure to the cylinder to act on the opposite side' of the piston. V v I 20. In a device of the type specified, the combination of a cylinder, a piston slidable in said cylinder, a chamber surrounding the cylinder and communicating therewith at I one end thereof, a quantity of mercury in the chamber maintained at the same level in the cylinder, means'tor supplying steam to the chamber under velocity pressure to act through the mercury on one side of the piston,and means for supplying steam to the cylinder uneer static pressure to act against the opposite side of the piston. In testimony whereot Iafiix my signature.

WILLIAM H. LARKIN, JR.

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