US1985404A

US1985404A - Means for regulating a steam turbine

Info

Publication number: US1985404A
Application number: US653047A
Authority: US
Inventors: Josef Y Dahlstrand
Original assignee: Murray Iron Works Co
Current assignee: Murray Iron Works Co
Priority date: 1933-01-23
Filing date: 1933-01-23
Publication date: 1934-12-25
Anticipated expiration: 1951-12-25

Description

1934- .1" Y. DAHLSTRAND MEANS FOR REGULATING A STEAM TURBINE Filed Jan. 23, 1933 4 Sheets-Sheet ATTORNEY Dec. 25, 1934. v Y A AND 1,985,404

MEANS FOR REGULATING A STEAM TURBINE 4 Sheets-Sheet 2 Filed Jan. 25, 1933 Y fl iw ATTORNEY Dec. 25, 1934- J. Y.-I DAHLSTRAND 1,935,404

' MEANS FOR REGULATING A STEAM TURBINE Filed Jan. 23, 1935 4 SheetsSheet 5 P3 P4 P5 P6 75 INVENTOR 1 %Y 8 B 7M 4 57 15 ATTORNEY Dec. 25, 1934.

J. Y. DAHLSTRAND MEANS FOR REGULATING A STEAM TURBINE Filed Jan. 23, 1935 4 Sheets-Sheet 4 M w W a g 3% w m M al W V B M\ l /\v| w 3, mam 4: p i H RY N3 v Sh 1 m3 3 e3 v2 mm 9% m LE m mum w n .QS.

WW H8 3 Nun mi E @3 wow a Q N. NH \QN NNH 3N EH v H @NH NH m3 Hm Q Patented Dec. 25, 1934 UNITED STATES MEANS FOR REGULATING A STEAM TURBINE Josef Y. Dahlstrand, Burlington, Iowa, assignor to Murray Iron Works Company, Burlington, Iowa, a corporation of Iowaj Application January 23, 1933, Serial No. 653,047

10 Claims.

This invention relates tomeans for regulating a steam turbine of the impulse type.

In steam turbines of the impulse type the kinetic energy of steam jets impinging on curved blades 5 or buckets fixed to a turbine wheel is converted into mechanical work. The steam jets are produced by expanding steam in nozzles which extend at an angle to the plane of rotation of the wheel and these nozzles have restricted throats 1O communicating with the steam ring or bowl of the turbine and relatively enlarged mouths opening in juxtaposition to the path of the blades on the wheel.

Turbines are often operated under varying load 15 conditions and require regulation to compensate for the variations in the load. This'has been done in the past by interposing a governing valve between the supply line and the ring of the turbine to regulate the steam flow. Such a valve creates a pressure diiierential between the steam in the supply line and that in the ring and the valve throttles the steam with a resultant waste'of British thermal units. Poppet valves have also been employed to regulate turbines but these valves also throttle the steam.

The salient object of my invention is to regulate theoperation of a turbine without creating a pressure difierential between the steam in the supply line and that in the ring of the turbine 30 to thereby avoid throttling the steam and the resultant waste of British thermal units.

Turbines are usually-rated to be operated at a given speed under a determinedring pressure and under these conditions the highest efficiency is attained. If a throttling governing valve is employed and there is a material reductionof the load on the turbine, the governing valve so operates that the ring pressure in the turbine is materially reduced. The nozzles are divergent, this being essential to expand the steam'below fiftyeight percent of the initial pressure. To provide a divergent nozzle, the area of the throat is made less than the area of the mouth and the divergence or taper of the nozzle, known as the expansion ratio, is a function of the ratio be tween the ring pressure and the stage back pressure in the turbine. Hence, when the ring pressure is materially reduced, the steam consumption greatly increases and the efficiency of the turbine is reduced. Moreover, calculation of the expansion ratio of a particular set of nozzles is partially based on the stage back pressure. As the load on the turbines lightens, the stage back pressure lessens 4 and it is beneficial to vary the expansion ratio to compensate for a reduction in back pressure. However, nozzles may be under-expanded in an appreciable amount without affecting their eificiency but over-expansion of the nozzles materially affects the efiiciency thereof.

Therefore, still another object of my invention is to provide a turbine wherein the expansion ratio of the nozzles may be adjusted to afford eficient operation under various operating conditions including a material reduction in stage back pressure. The power developed by a turbine is proportionate to the quantity of steam. admitted and hence, when the load on the turbine is materially reduced, it is advantageous to reduce the steam admission and this may be done by reducing the aggregate nozzle area. 1

Another object is to regulate'theoperation of a turbine by controlling the steam flow through the nozzles without reducingthe ring pressure so that maximum efiiciency may be maintained and an ancillary object is to vary the aggregate nozzle area of the turbine proportionately to the load.

A turbine'is often arranged so that steam may be withdrawn therefrom at one or more stages in order that steam'at' different temperatures and pressures may be supplied to appliances such as cooking vats and the like, and a turbine so equipped is known as a bleeder turbine. Heretofore, a throttling'valve has been provided'to regulate the bleed froma turbine but the use of such a valve is subject to many disadvantages. Hence, a further object of this invention is to provide a novel bleeder turbine in which the steam withdrawal is controlled by varying the area of the outlet nozzles from the bleeder chamber.

Still further objects of the invention are provide a turbine having novel reamed nozzles into which tapered adjustable needle valves are extended to aiford variation of the nozzle area and expansion ratio; to. automatically actuate the needle valves proportionately to variations in operating conditions; to control a plurality of nozzles so that wide variations in operating conditions may be accommodated; to provide an expeditious adjustment so that the same'turbine may be used under different operating conditions such as variations in initial steam pressure, load, andspeed; and to provide a novel turbine control of simple and economical construction and efficient and positive operation.

Selected embodiments of the invention are illustrated in theaccompanying drawings wherein Fig-l isa plan view Fig. '7 is a vertical sectional view taken sub-,

stantially on the line 7'7 on Fig. 4;

Fig. 8 is a vertical sectional view takensubstantially on the line 88 on Fig. 1; and

' Fig. 9 is a fragmentary vertical sectional view taken substantially on the line;9- 9 on Fig.2.

In the accompanying drawings, 10 indicates a base supporting a turbine casing 11 having

end plates

12 and 13 providing bearings in :which a turbine shaft 14 is journaled. A ring or bowl 15 is provided in the end plate 12 and this end plate includes a wall :16 in-which the nozzles 17 are provided. "The first stage wheel 18 of the turbine isijfast on;the shaft 14 adjacent 'thewall 16 and thebuckets or blades on the periphery of this wheel are arranged in two

rows

19 and 20. A diaphragm 21 is carried by the casing '11 and is interposed between the rows of buckets 19 and and has a rowof buckets 22 thereon. An inlet 23 has a valve 24 therein and leads to the ring 15. Steam flows through the inletinto *thering and through the nozzles 17 whichextend at an angle to the plane of rotation'of the wheel 18 and the jets of steam emitted from these nozzles first impinge on the buckets in the row 19, then on the buckets in the row '22, and thenon the buckets :in the row 20 from ,whence the steam flows into the bleeder chamber 25 when the turbine is equipped .withsuch .achamber behind the first stage therein. Ifnobleeder chamber is provided at this position, the steam flows into the second stage or to the exhaust as the case may ,be.

The nozzles l'l are of the .kind described'and claimed in my Patent No. 1,561,835, patentedNov b r .7, .1 5..a ,d1are s aigh leaniedhql In order to provide for efficient expansion of st am in the nozzles, whi h i usual p remplished by tapering the nozzles, tapered ;ne e d le valves 26 are extended into the th-rolats -of rthe nozzles and these tapered needle ivalves ,may ,be used to vary the aggregate nczzle areaas will be explained. In the illustrated embodimentof the invention, I show seven nozzles but a greater or less number might be provided depending upon the size of the turbine, the horsepower to be developed, the speed-of operatiomand the like.

The va1ve24 ispr e f h yo tb wfi rdine unobstructed steam passage and;henc e it does not have any throttling effect andsinceithe inlet 23 leadsdirectly to the ring or bowl and asthe intakes of the nozzles communicate with the ring, it is clear thatthe pressure at the intakesof the nozzles is line pressure. I

The seven nozzles provided in the illustrated turbine are arranged side by side and so far as constructional features are concerned, they are identical. The needle valve for each nozzle includes a stem 27 that is extended through a bore in thebody 28 mounted in a-tapped-opening inthe plate 12. Ahousing-29 is screwthreadedonto the end .of each body 28 and each has a chamber 30 therein in which packing nuts- 31 and 3 2 are provided. The stem 2? of each needlevalve extends vinto the housing ;,29 through the

packing nuts

31 and 32 and suitable packing engaged :by

these nuts so that when the nuts are tightened the packing is tightly clamped about the stems 27 to prevent leakage thereby. A cylinder 33 is provided in each housing and a piston 34 is reciprocably mounted in each cylinder. The outer ends of the stems 2'7 are respectively connected to the pistons. Chambers W arethus defined between the faces of the pistons towhichthe stems are connected and the adjacent ends of the cylinders.

Pins 35 extend axially from each piston 34 opposite to but in alinement with the stem 27 con nected to the piston and these pins project into bores in the caps 36 secured to the outer ends of thehQusings 29. Other chambers X are thus ,QGfiIIQd'bBUWBED the faces of the pistons to which .the' pins are connected and the adjacent ends of the cylinders. Tubes 37 are connected at the outer-ends of'each of the caps 36 and the bores in the tubes communicate with the bores in the caps. A chamber 38, Fig. 3, is provided in the base 10 atthe foreward end thereof. A tubular housing 39 projects through an opening 40 in the upperiwallofthe chamber and has a body 41 at the lower end thereof in which a gear pump 42 isprovided. A housing43 is securedto the upper end of the housing 39 and the shaft 14 extends thereinto. A gear 44 is fast on the shaft 14 in the housing 43 and meshes with a gear 45 fast on the. vertical shaft 46 journaled in suitable bearings provided in the housing 43. A coupling 47 interconnects the shaft 46 with the shaft 48 of the gearpump 42 so that when the shaft46 is 1'0- tated with the shaft 14 the gear pump is operated. 'Thechamber 38 serves as an oil reservoir and the gear pump withdraws oil from this reservoir and'forces the oil under. pressure through anoutlet tooperate certain devices as will be explained hereinafter.

Another housing 49 is mounted on the upper end of the housing .43 and encloses a weight-actuated governor 50,0f the usual construction and which includes a sleeve .51 disposed about the shaft 46. A spring52 isdisposed about the sleeve 51 andacts thereon ito urge the Weights of the governor towardthe shaft 46. Alever 53'has a link 54 .connected .to .one {end thereof and ,this link is pivotally connectedtoa lug 55in'thehousing 49. The sleeve 51 is connccted,to the lever 53 adjacent the end thereof connected to the link 54. Linksfidare pivotally-mounted on a rod 5'? carried by-the forkedend of the lever 53 opposite the end thereof connectedtothe link 54. One end of a spring ;5 8,is connectedzto the lever 53 intermediate the lrodfi'? and the connection thereof to the sleeve 5gl. -Theother end ,of the spring 58 is connectedto an adjusting devicemounted in the top plateof :the housing 49 and by means of which-thetensionon, the lever 53 may tie-varied.

Theneedlewalves are controlled bythe governor 59 and preferably thesevalves are so arranged that each can beoperated independently. This may be accomplished in a variety of waysand-in the illustrated embodiment of the invention I have shown pressure-actuated means for this purpose. I;h e pressure-actuated means provided for each-cf the needle valves includes a cylinder havinga;piston--thereinand a pilot valve for controlling movement of the piston in the cylinder. The pilot valves ,are actuated by thegovernor 50 and to this end the free ends of the links 56 are connected-to ;a rod-61. Seven bell cranks 6c are mounted at spaced intervalson the rod 61. The arms 62 of each of the bell cranks are pivotally connectedat 63 to sleeves 164 adj ustably mounted Q1 r99 5 6. ertend dthroueh pa in nu s and the plungers in their reciprocation.

in-therblock B. Conduits 89 are connected to the suitable packing intoithe cylinders 66 whereat they are respectively connected to the pistons 67. The cylinders 66 are arranged in side-by-side relation and in-the illustrated embodiment are formed in a. block B, Fig. 6. A chamber Y is defined in each cylindertfi-intermediate the face of the piston 67 to whichthe rod is connected and the adjacent end of the cylinder. Pins 68 extend from the pistons 67 opposite to and in alinement with the rods 65 connected to the pistons and these pins project into sleeves 69 leading from the cylinders 66. A'chamber Z is defined in each cylinder 66" intermediate the face of the piston 67 to which the pin 68 is connected and the adjacent end of the cylinder. The tubes 37' which are respectively connected to the caps 36 are respectively connected to the sleeves 59 and the tube leading from the firstof theneedle valves is connected to the first of the sleeves 69 while the tube leading fromthe second of the needle valves is connected to the second of the sleeves 69 and so on in succession. The respective tubes 37 are entirely filled with balls '70 so that the space between each set of pins 35 and 68 is entirely filled and preferably these balls operate in a light lubricating oil to insure free movement.

Seven'pilot valves are provided in the block B and these valvesare respectively alined with the cylinders 66. Each pilot valve includes a plunger P and these plungers are respectively connected to the arms '71 of the bell cranks 60 by pins 72 (Figs. 3and 5) disposed in slots '73 in the blocks 74 adjustably mounted on therods 75 respectively connectedto the upper ends of the plungers P. Each of the plungers isrecipro cal in a sleeve '77 and these sleeves are fitted in vertical bores 73 in the block B. Passages '79 in the block B interconnect the respective pilot valves and thechambers Y in the cylinders 66 respectively alined with the valves. The ends of these passages outwardly of the pilot valves are closed by plugs 80. Ports '79 are provided in the sleeves '77 in alineinent with the passages 79. A passage 81 is drilled through the block B and the sleeves 77 and interconnects the various sleeves. An intake pipe. 82 is connected at one end of the passage 81 and this pipe is likewise connected to the outlet ofthe pump 42. An outlet pipe 83 is connected to the other end of the passage 81 and leads to the chamberiifi. The ports '79 are disposed in the sleeves 7'! above the passage 81. Collars 84 are provided on I the plungers P which slide on the sleeves 7'? to open and close the ports '79. Enlarged portions 85 are provided at theupper ends of the plungers P which also slide on the sleeves 7'7 and guide The pertions of the plungers P intermediate the collars 84 and the enlarged portions 85 are relieved. When the collars 84 are positioned in the sleeves to be disposed below the passage 81, this passage and the ports '79 are in communication due to the relief of the plungers. be moved into such a position that communication between the passage 81 and the ports '79 is shutoff. 1

Collars 86 are provided at the lower ends of the plungers P and the portions of the plungers inter-- mediate the collars 84 and 86 are relieved so that when the collars 84 arepositioned in the sleeves to be disposed'above the passage 83.,oil flowing through said passage may flow past the relieved portions of the plungers P. Ports 87 are providedadjacent the lower ends of the sleeves 7'7 and respectively communicate with passages 88 The collars 84 may respective passages 88 and lead to the housings 29 to communicate with the chambers W therein. The collars-fifi controlflow of oil through the ports 8'? and when the plungers P are so disposedthat the collars 86 open the ports 87 for communication with the relieved portions of the plungers P intermediate the collars 84 and 86, oil flows to the conduits 89 into the chambers W. The plungers 1? may be so positioned that the collars 88 close oii the ports 87 from communication with the passage 81. Likewise the plungers may be so disposed that the collars 86 open communication between the ports 87 and the open lower ends of the sleeves 77.

A chamber 91 is provided at the bottom or" the block B and the bores '78 and sleeves 77 open into this chamber. A transverse passage 92 in the block B establishes communication between the chambers Z of the cylinders 66 and the cham ber 91 so that any oil leaking past the pistons 67 flows into said chamber. Each plunger P includes a bore 81 which extends axially therethrough from the lower end thereof to'a port located in the relieved portion of the plunger P intermediate the collar 34 thereon and the enlarged portion thereof. The collars s4 control communication between the ports '79 and the ports 80 and, when communication is opened between the ports 79' and the ports 80, oil may flow through the bore 81 into the chamber 91. An, outlet pipe 93 leads-from the chamber 91 to thereservoir 38. A drain pipe leads from each of the chambers X in the housings 29 to the reservoir 38 so that any oil seeping past the pistons 34 may be returned to the reservoir. I

The nozzles are so calculated that when all are open sufiicient steam flows ,therethrough' to efficiently operate'theturbine under a load greater than its rated, capacity. In this turbine, wherein seven needle valves are provided, and when it is operated under a load of seventy-five percent of its rated capacity, which obviously requires less steam than when the turbine is operated under a load of its rated capacity or more than its rated capacity, some of the nozzles may be closedoff. By Way of example, when the turbine is operat ing under a seventy-five percent load, two of the needle valves are tightly seated on the intakes of their nozzles so that no steam flows through these nozzles. When the load is decreased, say for example to twenty-five percent of the rated capacity of the turbinejiour of the needle valves are tightly seated on the intakes of their nozzles to close off steam flow vtherethrough. Thus, by seating or unseating the needle valves from their nozzles, the aggregate nozzle area may be varied and I vary this aggregate nozzle area proportionately to the load on the turbine. The speed of the turbine is determined by the load thereon for it operates at slightly different speeds at different loads and hence changes in load affect the governor fill-and since the pilot valves are controlled by the governor 50 and as these. pilot valves, in turn, control the means regulating the needle valves, I am enabled to control the steam fiowfro'in the ring or bowl into the first stage proportionately to the load on the turbine.

As stated, when the turbine is operating under a load of seventy-five percent of its rated ca- F pacity, two of the needle valves are seated on the intakes their nozzles. Underthis condition, four of the nozzles are opened fully and one is used for regulating purposes, as will be explained. This is accomplished by setting the .plungers P at different positions in the sleeves '77. Thus, the plunger P which regulates the movement of the piston 6'7 in the cylinder 66.con-, nected through a tube 37 to the first of the needle valves, is so positioned that when the turbine is operating in the manner just described, the collar 86 thereon is disposed below its cooperating port 87 and therefore oil flows from the passage 81 through the port 87, passage 81 and conduit 89 into the chamber W of the housing 29 of ;the first needle valve and the pressure of this oil acts on the piston 34 to force it against the outer end or the cylinder 33 as illustrated in Fig. '7. At this same time the collar 84 is so positioned that communication is opened between the port 79 and the port 80' and therefore oil pressure in the chamber Y may be relieved for oilmay flow from the chamber Y through passage 79, port '79, port 80, bore 81 into the chamber 91 to be returned to the reservoir 38. The plunger P is positioned somewhat similarly to the plunger P so that oil may flow into the chamber W in the housing 29 of the needle valve for the second nozzle. However, the plunger P2 is so positioned that upon conjoint movement of the plungers P and P (the plungers all being connected to the rod 61 for such movement with the rod), the collars 86 and 84 on the plunger P will close of"? oil flow in the above described man ner before the collars as and 86 on the plunger P so act. Inasmuch as four nozzles are to be wide open when the turbine is operating at seventy-five percent of its rated capacity, the plungers P and P are also so positioned that oil will flow to the chambers W in the housings 29 for the needle valves of the third and fourth nozzles. However, the plungers P and P' are respectively so positioned relative to the plungers P and P that the collars 84 and 86 on'the plunger P will close off the foregoing communication upon'conjoint movement of the plungers prior to the time the collars 84 and 86 on the plunger P close off communication, and likewise the collars 8 1 and 86 on the plunger P are positioned to close off communication before the collars 84 and 86 on the plunger P so close off communication. The plunger P is also set relative to the plunger P so that the collars 84 and 86 thereon will close off the foregoing communication prior to the time the collars 84 and 86 on the plunger P so operate. However, when the machine is operating at seventy-five percent of its rated capacity, the collar 84 on the plunger P is arranged in the manner shown in Fig. 3, that is to say, it is disposed directly over the port '79 so that communication through this port is shut off. Likewise, the collar 86 on the plunger P is disposed over the port 87 so that communication through this port is shut off. The plunger P is so set that the collars es and 86'thereon are advanced beyond the position or" the collars 84.- and 86 on the plunger P Hence, since the collars 84 and 86 are disposed directly over the outlet of the passage "19 and the port 87, it is clear that the collars 84 and 86 on the. plunger P are arranged in an opposite manner to the collars 84 and 86 on the plunger P Hence, the collar 84 on the plunger P is so disposed that communication is opened between the passage 81 and the port 79 and hence'oil flows from the passage 81, past the relieved portion of the plunger, through port 79', and through the passage '79 into the chamber Y of the cylinder alined with the pilot valve including the plunger P and the pressure of the oil-acts on the piston 67 to force the same toward the chamber Z. At this same time :the collar =86 is so disposed that communication is opened between the port 87 and the chamber 91. The oil pressure on the :piston'fi'? tends to force the pin 68 through the sleeve 69 and this movement is transmitted through the balls to the pin 35 connected to thepiston 34 in the cylinder 33 of the housing 29 for the valve of the sixth nozzle and this urges the piston '34 toward the chamber W. At this time oil is free to flow from the chamber W through the conduit 89, passage 81, port 87 into chamber 91 and therefore the oil pressure on the piston 67 so acts that the needle valve 26 for the sixth nozzle is urged into seating engagement with the intake of the nozzles and closes off this nozzle. The collars 84 and 86 on the plunger 1 are positioned similarly to the collars '84 and 860m the plunger P but these collars'are so arranged that communication to the chamber Y of the seventh cylinder will be established prior to the time communication is established to the chamber Y of the sixth cylinder and likewise communication will be opened from the chamber W of the seventh needle valve prior to the time communication is opened from i the chamber W of'the sixthineedle valve. Hence, when the machine is operating at seventy-five percent of its rated capacity, four'needle valves are held in wide'open position and two are closed.

The other needle valve is so arranged that it can fluctuate to compensate for slight variations in the speed of the turbine. When the turbine is loaded to seventy-five percent of its rated capacity, it operates at a predetermined speed and the weights of the governor assume a determined position. When, however, the load on the turbine is decreased, and thesteam flow from the ring or bowl is to be decreased, the turbine speeds up which causes the weights of the governor 50 to move outwardly and therefore the sleeve 51 is moved upwardly. Upward movement of the sleeve 51 moves the lever 53 and the links 56 upwardly and consequently raises the rod 61. All of the plungers P are connected to the rod 61 and hence when this rod 61 moves upwardly all of the plungers move similarly, the bell cranks fulcruming about the pivotal connections 63. However, when the movement is slight, none of the plungers are moved suiiiciently to aifect the needle valves controlled thereby except the plunger P Since the collars on this plunger are positioned directly over the ports '79 and 87, slight movement of the plunger P opens these ports. Hence, when, as described, the rod 61 moves upwardly, indicating an increase in speed of the turbine, which is indicative of a decrease in the load, it is essential that the steam supply be slightly reduced in order to bring the turbine back to its normal speed for a seventy-five percent load. Therefore, when the plunger P moves upwardly, the collar 84 thereon moves into such a position that communication is established between the passage 81 and the port '79 and passage '79 leading to the fifth cylinder and therefore additional oil flows into the chamber Y which moves the piston 67 to move the pin 68 through'the sleeve 69 and this movement is transmitted through the balls 70 to the pin 35 to move the piston 34 of the fifth needle valve toward the chamber W and, since at this time communication is established between the port 87 and the chamber 91, movement of the piston 34 toward the "chamber W forces oil from the chamber W into the chamber 91. At the time the piston 67 moves in the manner just described, the pin 65 is, of course, moved; This changes the position of the pivotal connection 63 and the fifth bell crank pivots about the rod 61 which moves the arm 71 of the fifth bell crank and causes the pin '72 thereon to move through the slot 73 and this forces theplunger P downwardly so that the collars 84 and 86 move back into position to close off the passage 79 and the port 87. 1 Thus, the fifth needle valve is returned in the position into which it has been moved. However, since the fifth needle valve has been moved inwardly in. a slight amount, the steam flow through the fifth needle valve is reduced which may be sufficient to cause a decrease in the speed of the turbine. Therefore, the weights of the governor 50 are moved inwardly and the spring 52 acts to move the sleeve 51 downwardly. This moves the lever 53 and the links 56 downwardly and consequently the rod 61 also moves downwardly and pivots the bell cranks 60 about the connection 63. However, this movement will be slight and none of the plungers P will bemovedsufilciently to afiect the seating of the needle valves controlled there? by except the plunger P This plunger will so move under these conditions that the collar 84 thereon will move from position over the port '79 and open communication between the chamber Y and the port 80 At this same time the collar 86 opens communication between the port 8'7 and the passage 81. Hence oil flows through the port 87, passage 83 and conduit. 89 into the chamber W of the fifth needle valve and the pressure of this oil acts on the piston. 34 to move this piston toward the chamber. X and this movement is transmitted through the balls 70 so that the piston 67 is urged toward the chamber Y, and oil is forced from the chamber Y through thepassage 79, port 79', port 80' and bore 81' into the chamber 91. However, when the piston 67 moves upwardly, the pin 65 is also moved upwardlyand the fifth bell crank fulcrums on the rod 61 and the pin '72 moves through the slot '73 to move the plunger P back into position whereat the collar 84 shuts off the port '79 and the collar 86 closes the port 87. 1

The fifth needle valve continues to fluctuate in thismanner solongas there are slight varia-..

tions in the turbine operating speed and the .turbine continues to operate under-a seventy-five percent load. Howeven-when there is a material reduction in theload, on the turbine, say for example, when the load is reduced to twentyfive percent of the rated capacity of the turbine, there is a noticeable increase in speed of the turbine. This causes the weights of the governor 50 to move outwardly which causes the sleeve'51, links 56 lever 53 and rod 61 to move upwardly and in this instance the movement of the rod 61 is suficiently to move the plungers P and P into positions similar to that in which the plungers P and P have been disposed; that is to say, so that communication is established between the chambers W of the fourth and fifth needle valves and the chamber 91 and so thatcommunication is opened between the chambers Y of the fourth and fifth cylinders and the passage 81. There-'- fore, oil flows into these chambers Y and acts in the above described manner to seat the needle valves on the intakes of the fourth and fifth nozzles to thereby close ofi these nozzles. The foregoing movement moves the plunger P into a position similar to that shown in Fig. 3 so that this plunger P then begins to operate in the manner in which the plunger P operates when the turbine is operating under seventy-five percent load con-' ditions. The normal turbine speed for a twentyfive percent load is different from that for aseventy+five percent load and therefore notwithstanding the fact that two nozzles have been shut off entirely, the turbine will not slow down to the speed at which it was operating before the foregoing change occurred. Hence, the rod 61 is disposed in a slightly difierent position and the various plungers are so disposed that the fourth, fifth, sixth and. seventh needle valves remain closed whereas the first and second remain open and the third needle .valve fluctuates to care for slight variations in speed.

If the machine is operating under twenty-five percent load as just described and the load is increased to one hundred percent load, the turbine slows down, the. weights of the governor 50 move inwardly, and the spring 52 acts to move the sleeve 51 downwardly and therefore the lever 53, links 56 and rod 61 move downwardly, and this movement of the rod 61 is sufficient to so position the plungers that the first, second, third,

fourth and fifth needle valves are open wide while the seventh needle valve remains closed and at this time the sixth needle valve is fluctuated in the manner in which the fifth needle valve fluctuates when the machine is operating under a seventy-five percent load, as described above. If the machine is overloaded, the rod 61 moves downwardly still more and the sixthneedle valve is opened wide and the seventh needle valve then fluctuates in the manner described to care for slight variations in turbine speed.

From the foregoing it will be apparent that I have provided an arrangement which regulates the operation of a turbine without throttling the steam. The device so operates that the steam input to the first stage is controlled proportionately to the load on the-turbine and furthermore the device so operates that the steam input is varied proportionately to slight variations in the-load or speed of the turbine and this regulation for slight variations in speed operates under a great variety of load conditions; that is to say, it is effective either in fractional loads, normal load. or overload.

In the illustrated turbine, a bleeder chamber 25 .is provided between the first and second stages. This'chamber includes a bleeder outlet 95 to which a steam line 95 is connected so that steam bled from the turbine may be directed to applianoes'in which the steam is used for heating purposes and the like. As these appliances are turned on and off the steam consumption varies which varies the pressure in the bleeder line and consequently in the bleeder chamber 25.

One of the objects of this invention is to maintain a constant pressure in the bleeder line and bleeder chamber without throttling the steam and to this end nozzles 96 are provided in the wall 94 at the inner end of the bleeder chamber 25. The nozzles 96, whichare similar to the nozzles 17, extend'at an angle to the plane of rotation of the second stage wheel 97 fast on the shaft 14 admay pass directly to the exhaust, any of these arrangements being in accordance with thewellunderstood practice.

In order to regulate the pressure in the chamber without throttling the steam, needle valves 99, substantially similar to the needle valves 26, are provided'for the nozzles 96.

As the pressure in the chamber 25 falls means are provided for closing off one or more of the nozzles 96, six nozzles being provided in the illustrated turbine. As the pressure in the chamber 25 rises, additional nozzles are rendered operative so as to increase the steam fiow tothe second stage which will reduce the pressure in the chamber 25.

Inasmuch as the steam flow through the'nozzles 96 is determined in accordance with the pressure in the chamber 25 or the bleeder line, pressure responsive means are provided for controlling the operation of the needle valves 99. This pressure responsive means, illustrated in detail in Fig. 8, includes a body 100 secured to the turbine casing 11. A cylinder 101 is provided in the body 100 and a piston 102 is reciprocal therein. A conduit 103 leads from the pressure chamber 25 to one end of the cylinder 101 and pressure variations in the chamber 25 are transmitted through this conduit to the cylinder 101 whereby the position of the piston 102 is varied. The piston includes a shouldered end 103 and extends into a chamher 104 in the body100 above and about the cylinder 101. A spring 105 in the chamber 104 bears on the shouldered end 103 of the piston and against an adjusting nut 106. By varying the position of the adjusting nut 106, the tension of the spring 105 may be varied which affords an adjustment for regulating the operation of the device. A rod 107 is connected to the shouldered end 103 of the piston 102 and extends out through an opening 108 in the nut 106. One-end of a lever 109 is pivotally connected at 110 to a sleeve 111 adjustably mounted on the rod 107. The lever 109 is connected intermediate its ends at 112 to a sleeve 113 adjustably mounted in the rod 114 which extends through a packing gland into the cylinder 115 provided in the body 100 and this end of the rod is connected to a piston reciprocal in the cylinder 115. The forked end of the lever 109 opposite to that connected to the sleeve 111 is pivotally connected at 116 to links 117. The links 117 are pivotally connected to a rod 118. In the present instance, Where six nozzles and needle valves are provided, six bell cranks 120 are provided and the arms 119 of these bellcranks are pivotally connected to the rod 118. Pins 121 in the bell cranks extend into slots 122 in blocks 123 adjustably mounted on rods 124. The rods 124 are connected to the upper end portions 125 of the plungers V of the pilot valves 126. A block 127, similar to the block B, is provided and the valves 126 are formed in this block as are six cylinders 127 in which pistons 133 are reciprocal. Rods 131 are connected to the pistons 133 and extend from the cylinders through suitable packing glands and have sleeves adjustably mounted thereon. The arms 128 of the bell cranks 120 are pivotally connected at 129 to the sleeves 130.

Pins 134 project from the pistons 133 opposite to and in alinement with the rods 131 and these pins extend into sleeves 135 mounted at the lower ends of the cylinders 132. Tubes 136 are respec tively connected to the sleeves 135 and these tubes are respectively connected to caps 139 provided at the outer end of the bodies 140 of the needle er chamber after the second 'stage'or .the steam valves cooperating with the six nozzles. The tubes 136 are filled with balls 137 which are arranged similarly to the balls 70.

In operation, certain of the needle valves are arranged to be wide open and others are seated against the intakes of their nozzles and this arrangement is such that, so long as a predetermined pressure is maintained in the bleeder chamber '25, the needle valves remain in this position. One needle valve is arranged to fluctuate (in the manner previously described so .as to care for .slight variations in pressure, slight variations in pressure imparting small movement to the piston 102 which moves the rod 107 which, in turn, pivots the lever 109 about its fulcrum 112. This movement istransmitted through the links 117 to the rod 118 to lower the rod 118 when the pressure in the chamber 25 rises and to raise the rod 118 as the pressure falls. The plungers V are arranged in staggered relation in the same manner as the plungers P and hence, when the rod 118 moves downwardly, communication is established between the oil intake line 141 and the conduits 142 which lead .to chambers in the bodies 140 substantially similar to the chambers W. the number of conduits 142 connected to the intake line 141 being dependent upon the pressure, it being apparent that when oil flows through the conduits 142 the needle valves '99 are moved into .open position. The oil intake line 141 is connected to the oil supply line 82, Fig. 3. Likewise, when the pressure drops and the rod 118 moves upwardly, the plungers V also move upwardly and said plungers close off communication to one .or more of the conduits 142 and open communication into one or more of the cylinders 132 to act on the pistons 133 therein to move the pins 134 through the sleeves 135 to thereby force :the'needle valves towhich the various tubes 136 lead inwardly to seat on the intakes of the nozzles. 'As stated, one of the nozzles, which is always the nozzle adjacent the last wide open nozzle, fluctuates to care for slight variations in pressure- The provision of a plurality of nozzles leading from the bleeder'chamber and the provision of means for controlling steam flow through these nozzles enables me to care for variations in pressure in the bleeder chamber without throttling the steam and, by providing a plurality of nozzles, I'am enabled to care for wide variations in pressure. At the same time, the arrangement is such that compensation is made for slight variations in pressure and therefore it is possible to maintain within relatively narrow limits a desired pressure in the bleeder chamber.

It will be apparent from the foregoing description that I have provided a method and means for regulating a turbine so that the steam input may be kept proportionate to the load on the turbine and furthermore I am enabled to maintain the turbine speed within definite narrow limits. Moreover, the arrangement is susceptible for use in connection with a bleeder chamber so that desired pressure may be maintained in the bleeder chamber and bleeder line. Since the arrange ment is such that it directly controls the steam flow through the nozzles, it is possible to regulate the operation of the turbine or the pressure in the bleeder chamber without throttling the steam which obviously increases the efficiency of the apparatus.

In the foregoing description I have described my invention in connection with a steam turbine but it is to be understood that steam is used in to hold a'gene'ric sense for my invention is'adaptable for use with any turbine employing an elastic fluid.

While I have illustrated and described selected embodiments of my invention, it is to be under stood that'these are capable of variation and modification and 'I therefore do not wish to be limited to the precise details set forth but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

1. In a steam turbine, a wheel having buckets thereon, a plurality of nozzles for emitting jets of steam to the buckets on said wheel, a needle valve for each of said nozzles and shaped to determine the expansion ratio of the nozzle with which it cooperates when extended into the inlet of said nozzle and movable between closed and wide open positions relative to said inlet and into positions intermediate the closed and wide open positions, the position of said needle valves relative to the inlets of said nozzles regulating steam emission from the nozzles,'fiuid operated for independently eifecting movement of the-needle valves into closed and wide open positions and positions intermediate the-closed and wide open positions, means for controlling op eration of the turbine proportionately to operat ing conditions thereof and operable to selectively actuate said fluid operated means to selectively position said needle valves in closed or wide open positions or in positions intermediate closed and Wide open positions to regulate steam emission to said buckets, and second fluid operated means cooperating with the first fluid operated means said needle valves in the positions into which they are moved upon operation of the means controlling operation of the turbine, said means controlling operation of the turbine in cluding pilot valves for regulating flow of fluid ito the first and second fluid operated means.

2. In a steam turbine, a wheel having buckets thereon, a plurality of nozzles for emitting jets of steam to the buckets on said wheel, a needle valve for each of said nozzles and shaped to determine the expansion ratio of the nozzle with which it cooperates when extended into the inlet of said nozzle and movable between closed and wide open positions relative to said inlet and into positions intermediate the closed and wide open positions, the positions of said needle valves relative to the inlets of said'nozzles regulating steam emission from the nozzles, fiuid operated means for independently effecting-movement of the needle valves into closed and wide open p0- -sitions and positions intermediate the closed and wide open positions, means for controlling operation of the turbine proportionately to operating conditions thereof and operable to selectively actuate said fluid operated means to selectively position said needle valves in closed or wide open positions or in positions intermediate closed and wide open positions to regulate steam emission to said buckets, and second fluid operated means" cooperating with the first fluid operated means to hold said needle valves in the positions into which they are moved upon operation of the means controlling operation of the turbine, said means controlling operation of the turbine including pilot valves for regulating flow of-fluid to the'first and second fluid operated means, and means common to said pilot valves andoperable ,upon operation of said means controlling operation of the turbine to selectively control the flow of fluid to said first and second fluid operated means.

.' 3. In a steam turbine, a wheel having buckets thereon, a plurality of nozzles for emitting jets of steam to the buckets on said wheel, a needle valve for each of said nozzles and shaped to determine the expansion ratio of the nozzle with which it cooperates when extended into the inlet'of said nozzle and movable between closed and wide open positions relative to said inlet and into positions intermediatethe closed and wide open positions, the positions of said needle valves relative to the inlets of said nozdle valves in the positions into which they are i moved upon operation of the means controlling operation of the turbine, said means controlling operation of the turbine including pilot valves for regulating flow of fluid to the first and second fluid operated means, and means to which all of said pilot valves are connected whereby all of said pilot valves aremoved upon operation of said means controlling the operation of the turbine.

4. In a steam turbine, a wheel having buckets thereon, a nozzle for emitting a jet of steam to the buckets on said wheel, a needle valve for said nozzle and shaped to determine the expansion ratio of the nozzle when extended into the inlet of said nozzle and movable between closed and wide open positions relative to said inlet and into positions intermediate the closed and wide open positions, a cylinder, a piston in said cylinder, said needle valve including a stem exw tended into said cylinder and connected to said piston whereby said needle valve is movable with said piston, means for admitting fluid to said cylinder on both sides of saidpiston to effect movement of said piston and said needle valve,

and means cooperating with said piston on the side thereof opposite to that whereat said stem is connected and adapted to retain said piston in positions into which it ismoved by fluid adimitted into said cylinder on the side of said piston whereat said stem is connected.

5. In a steam turbine, a wheel having buckets thereon, a nozzle for emitting a jet of steam to the buckets on said wheel, a needle-valve for said nozzle and shaped to determine the expansion ratio of the nozzle when extended into the inlet of said nozzle and movable between closed and wide open positions relative to said inlet and into positions-intermediate the closed and wide open positions, a cylinder, a piston in said cylinder, said needle valve including a stem extended into said cylinder and connected to said piston whereby i said needle valve is movable with said piston,

means for admitting fluid to said cylinder on both sides of said piston to effect movement of said piston and said needle valve, a second cylinder,

for transmitting the movement of one of said pistons to the other of said pistons, and means fonadmittinga fluid :un-denprcssure. to: the second cylinder. to hold the pistonztherein againstpmovee mentiinone direction. wherebyithe pistonto which said stem is connected may be retained in positions into which it is'm'oved by-fluid admitted into the first cylinder on the side of .the piston-thereinwhereat said stem is connected;

6. lnasteamzturbine a wheel having'buckets thereon, a nozzlefor: emitting a: jet of: steam to the bucketson said wheel, .a needle: valve" ion-said nozzle and shapedto determine the expansionratio of the nozzle when extended intQtheiinletof said nozzle and movable between closed-and wide open' positions relative to saidinlet and into positions intermediate the closed and wide open positions, a. cylinder, a piston in, said cylinder, said needle-valve including a stem extended into said.

cylinder and connected to said piston whereby said needle valve is movable with said piston, means for admitting fluid to said cylindersonboth'. sides of said piston to effect movementv of. said; pistonandsaidneedle valve, a'secondcylinder; a piston in saidsecond cylinder, a device extended between said: cylinders and having means for transmitting the movement of one of'said pistons to the other of said pistons, means for. admitting :a'

fluid under pressure to the second cylindercto hold the piston therein against movement in-one' direction wherebythe piston to which said stem is connected may be retained in positions-into which it is moved by fluid: admittedintothe first cylinder on: the side of the piston: therein whereat said stem is' connected, and means including a pilot valve controlling fluid flow to both of said cylinders and regulating movement of said pistons.

'7. In a: steam turbine, a wheel'having b .ckets cylinder and connected to said piston whereby' said needle valve is. movable with said piston, means for admitting fluid to said cylinder on both sides of said piston to effect movement of said piston and said needle valve, a second cylinder, a piston in said second cylinder, adevice extended between saidcylinders and having means for transmitting the movement or" one of said pistons to the other of said pistons, means for admitting a fluid under-pressure to the sec-- ond cylinder to hold the piston therein against movement in one direction whereby the piston to which said stem is connected may. be retained in positions into which it is moved-by fluidadmitted into the first cylinder on the side of the piston therein whereat said. stem. is. connected; means including a pilot valve controllingfluid flow to both of said cylinders and regulating movement of said pistons, and meansresponsive-to operating conditions of the turbine for controlling the operation of said'pilot valveto regulate'fluid flow to said cylinders.

8. In a steam turbine, a wheel having buckets thereon. a nozzle for emitting a jet of steam to the buckets on said wheel, a needle valve for said nozzle and shaped to'determine the expansion ratio of thenozzle when extended into the. inlet of said nozzle-and movable between closed: and wide open. positions: relative to said inlet.

and. into positionsintermediate. the; ciosccb ancla wide open positionsa cylinder, a: pistonini said; cylinder; said needle valve including-a; stem-extended into said cylinder'and' connected: to said, piston whereby said needle valve is movable with said piston, means for admitting fluid to said cylinder on both. sides of said: piston to effect movement of said piston and said needle valve; means cooperating with said p-istonon. the side thereof opposite to that whereat said. stem is connected and adapted to. retain said piston in positions into which it is moved by fluidiadmitted into said cylinder on the side of said piston whereat said stem is connected, and means responsive to operating conditions of the turbine and controlling fluid admission to said cylinder to reg.-

.late the position of the piston therein and the position of said needle valve relative to said inlet.

9. In a steam turbine, a wheel having buckets thereon, a nozzle for emitting a jet of steam to the buckets on saidwheel, a needle valve for said nozzle and shaped to determine the expansion ratio of the nozzle whenextended into the inlet oi? said nozzle and movable between closed and wide open positions relative to said inlet and into positions intermediate the closed and wide open positions, a cylinder, a piston in said cylinder, said needle valve including a stem extended into said cylinder and connected to said piston whereby said needle valve is movable with said piston, means for admitting fluid to said cylinder on both sides of said piston to effect movement of said piston and said needle valve, a second cylinder, a piston in saidsecond cylinder, a deviceextended between said cylinders and having means for transmitting the movement of one of said pistons to the other of said pistons, means. for admitting a fluid under pressure tothe second cylinder to hold the piston therein against movement in one direction whereby the piston to which: saidstem iszconnected maybe retained inpositions into which it is moved by fluid-admitted'into the first cylinder on the side of the piston therein whereat said stem is connected, means including apiiot valve-controlling fluidrflow. to both ofsaid-s cylinders and regulatingv movement ofsaid pistons, and means responsive to'operating conditions of the turbine for; controlling, the operation of said pilot valve-to regulatefluid flow. to said, cylinders, said means responsive to the operating conditions of the turbine including a'movable member connected to the piston in thesecond cylinder, a member connected to said pilotvalve and having a slot therein, means on saidlmovable member disposed in. said slot tobe movable therealong, and means. connectingthe movable member to a device actuated by operating. conditions-of the turbine whereby actuation of said device moves said pilot valve whereupon movement eithe piston in the second'cylinder is effected and the movable member is moved with said-piston to move the means thereonin-said slot along said slot to move the pilot valve back into the position in which it was'disposed prior tomovement thereof upon actuation of the'deviceresponsive to operating. conditions of the turbine.

10. Ina-steam. turbine, awheel'having buckets thereonpa, nozzle .ior. emitting a jet of steam to the buckets on. saidwheel, .a needle valve for said nozzle and; shaped to determine the expansion. ratioof the'nozzlewhen extended into theinlet of said nozzle: and movable between closed and wide open positions relative tosaidLinlet. and into positions intermediate the closed and wideopen positions, a cylinder, a piston in said cylinder, said needle valve including a stem extended into said cylinder and connected to said piston whereby said needle valve is movable with said piston, means for admitting fluid to said cylinder on both sides of said piston to efiect movement of said piston and said needle valve, a second cylinder, a piston in said second cylinder, a device extended between said cylinders and having means for transmitting the movement of one of said pistons to the other of said pistons, means for admitting a fluid under pressure to the second cylinder to hold the piston therein against movement in one direction whereby the piston to which said stem is connected may be retained in positions into which it is moved by fluid admitted into the first cylinder on the side of the piston therein whereat said stem is connected, means including a pilot valve controlling fluid flow to both of said cylinders and regulating movement of said pistons, and means responsive to operating conditions of the turbine for controlling the operation of said pilot valve to regulate fluid flow to said cylinders, said means'responsive to the operating conditions of the turbine including a device actuated by changes in the operating conditions, a link connected to said device to be movable'thereby, a bell crank lever, means connecting the bell crank lever to the piston in the second cylinder, means connecting the bell crank lever to said link, said pilot valve including a part having a slot therein, means on the bell crank lever movable along said slot, movement of said link moving said bell crank lever to move the pilot valve to admit fluid at least to the second cylinder to move the piston therein and movement of the piston in the second cylinder moving said bell crank to move the means thereon in said slot along said slot to thereby move the pilot valve back into the position in which it was disposed prior to movement of said link.

' JOSEF Y. DAHLSTRAND.