USRE12285E - Apparatus for regulating the speed of steam-turbines - Google Patents

Description

No. 12,285. REISSUBD NOV. 15, 1904;

' G. 0. M. OLSSON.

APPARATUS POR REGULATING THE SPEED 0F STEAM TURBINBS.

APPLICATION FILED 0CT.1, 1904.

2 SHEETS-SHEET 1,

QM@ l ATTORNFY RBISSUED NOV. l5, 1904.

Y G. 0. M. OLSSONA APPARATUS POR RBGULATING THB SPEED OF STBAMTURBINBS.

APPLICATION FILED 00T.1, 1904.

2 SHEETS-SHEET 2.

41.0 type are commonly provided with an auto- 'When the load is removed, the throttle-valve 1S iS closed and n0 steam is admitted to the tur- 7 is alever having its fulcrum in a stud 3,

A`v regulator.

' 25 degree, this for kthe reason that the wheel when 3o prevent this undue increase of speed.

y um-chamberinclosingthe wheel,

)i1-Qi. 12,285. I i Rcissued November 15, 1904. UNITED STATES PATENT OFFICE.

`YGEORG OSCAR MAGN US OLSSON, OF STOCKHOLM, SlVEDEN, ASSlCrNOR TO THE DE LAVAL STEAM TURBINE COMPANY, A CORPORATION yOF NEW JERSEY.

i' APPARATUS FOR REGULATING THE SPEED OF STEAM-TURBINES.

srEc'IFIcA'rIoN forming-part of Reissued Letters Patent No. 12,285, dated November 15, 1904.

Original No. 701,500l dated June 3, 1902. Applicationfor reissue filed October 1, 1904. Serial No. 226,865.

To alhwmm it may concern:

Be it known thatI, GEORG OSCAR MAGNUs OLssON, a subject of the Kingnyf Sweden and Norway, residing at Stockholnilg Sweden, have i` Similar numbers of reference indicate like 5 invented a new and useful Improvement in l, l l l parts.

1 represents the casing; 2, the steam-turbine wheel thereof. Said wheel is mounted on a shaft 3, jonrnalcd in bearings, one of which is shown at 4, the other bearing and adjacent parts being broken away in Fig. 1 to show the arrangement of the air-valve. Y At is a throttlevalve communicating with the channel 6, and this channel leads to one or more steam-nozzles by which steam is delivered to the wheel. The arrangement of nozzles is well known in connection with turbines of the description referred to, and is therefore not illustrated.

Apparatus for Controlling the Speed of Steam- Turbines, of cation.

' Steam-turbines of the well-known De Laval which the following is aspecifimatic centrifugal regulator, which controls the speedby controlling the steam admission vvto the wheel in accordance with the load.

ybine-wheel. Nevertheless it frequently happens that throughithe presence of dirt or Vother foreign matter or because of wear the l said valve slightly leaks when closed by the When the steam-turbine is used with a condenser, the eiect of such leakage is serious, inasmuch as a veryT small admittance 'of steamto the wheel is sufficient to increase the speed of the latter beyond the tolerated which projects from the casing 1. The upper end of this lever is connected to the piston-rod 9, which carries the piston 10. This piston is contained in a cylinder 12, which is snpported on the rod 13. Between the piston 10 and the end of the cylinder and also surrounding the piston-rod is a coiled spring 11. The rod 13,/is connected to one arm of the bellcrank lever 14, the end of the other arm of which is received in a recess in the stem ofthe throttle-valve 5. 'The lower end of lever 7 is situated directly opposite a horizontal moving pin 16. This pin is actuated by a regulator, one form of which is shown in Figs. 3 and 4, so that when the pin 16 is moved to the right of Fig. 1 the valve 5 is closed and the steam is shut oi', thus diminishing the speed of the turbine -wheel. On the other hand, when the pin 16 is moved to the left the valve 5 is lifted, thus admitting more steam to the turbine and augmenting its speed. A regulatingdevice for actuating the pin 16 in the manner described is represented in Figs. 3 and 4.

27 is a shaft which is rotated by any suitable gearing from theturbine-whcel shaft. a recess in the end of this shaft is inserted the tapered shank 28 of the regulator-body. Said body consists of a recessed circular portion 29, a ring portion 30, and connecting-arms 31, one of whichl is indicated by dotted lines in Fig. 4.

32 and 33 are two arc-shaped weights surthe load is removed meets with substantially no 'resistance 'from the medium in which it rotatesf' l The object of the present invention is to in-y described whereby such abnormal speeding Of the wheel due to steam leakage is prevented by the admission of air into the vacusaid air then offering resistance to the motion of the wheel suflicient to reduce its velocity to the desired extent.

1n the accompanying drawings, Figure 1 is 49 avertical section of a steam-turbine of said De Laval typeexhibiting my apparatus applied thereto, and Fig. 2 is an enlarged vertical section of the air-controlling valve. Fig. 3

is an end view of the weights used in a form of regulatog which is adapted to control the pin 16 in the manner hereinafter described. Fig.

4 is a longitudinal section of said regulator on wenn@ ofrig. 3. l

l J My invention consists inthe apparatus hereweights closed in upon the body.

rounding' the ring 30 and of bell-crank form, each having :limite-edge 34. b v which it is l'ulcrunled in the circular portion 29 of said body, and each having' a pin 35, which bears against the disk 36. Said disk is carried b v the piu 16. 'ithin the ring 30, which is threaded, is a nut 37, through which the pin 16 passes. A helical spring 38 is interposed between disk 36 and nut 37. By operating the nut the pressure of said spring is regulated, and said spring' also serves to keep the YVhen the limit of speed of the tul'bine, and hence of the shaft 27. is exceeded, the weights 32 spread apart by centrifugal force and in so doing move their pins 35 against the disk 36, and the latter moves the pin 16 outwardly and to an extent proportionate to the speed. \Vhen the speed diminishes, the pin 16 is moved inwardly by the action of the spring'. The regulator may be provided with a casing, as shown yin Fig'. 1.

All ot' the foregoing construction except the cylinder 12, piston 1l), and spring 11, in terposed between rods T and 13, is old and well known.

After the steam has been cut oli' through closing of the throttlefvalve by means of such a regulator as is represented in Figs. 3 and 4 a possible leakage of steam around the throttle-valve may take place. My present device is intended for use when a vacuum is produced within the wheel-chamber, Such a condition occurs when, for example, a condenser is connected to the wheel-casing' by the pipe 17. The steam-turbine then running in what is practically a vacuum meets with substantially no resistance from the medium in which it rotates. On the other hand, the constant inflow 'of a small quantity ot' steam leaking past the throttle is a constant force, and therefore an accelerating one. Hence all the conditlons are present for causing the wheel rapidly to work up to a very high degree of.

speed, which for obvious reasons is disadvantageous and injurious. My method ot' prel venting this difiiculty consists in the admission of a small amount of air into the wheelchamber, the eli'ect ot' which is at once to provide a medium which will offer suliicient rel sistance tothe motion of the wheel to overcome the force tending to rotate the wheel derived from the small amount of leaking steam. This admission of air I preferably cause to be done automatically. One embod iment of' my aforesaid method is shown in an automatic apparatus, which I will now describe.

In the wall of the turbine-casing is screwed a hollowblock 18, the interior of which block is connected to the interior of the wheehcham- The block 18 ber by means of the pipe 20.

has a cylindrical bore, in which is placed a hollowcyliudrical valve 21. lrVlthln said valve one end of which bears is a coiled .spring against the nut 23, screwed on the rear end of' block 18. The closed end of the piston is beveled on its outer surface at 23* and is seated in a corrcspondinglyfbeveled opening 24 in the wall of the block 18. In said closed end of the piston is screwed a pin 25, having head 26. This head 26 comes directly opposite the lower end of the level` 7,'or, in other words, the lower end of .lever 7 is interposed between the moving pin 16 of the regulator' and the head 26 of the stem 25 of the valve 21.

The operation of the apparatus is as follows: Assume that the load on the steam-turbine is removed and thethrottle-valve closed by the action ofthe regulator-pin 16. It' now steam leaks past the throttle-valve 5, the speed of the turbine 2 will become augmented, and thereupon the regulator-pin 16 will continue to move to the right even after it has shut the valve 5, This it can do because the spring 11 ot' the cylinder l2 yields and permits the piston 10 thereofl to move to the left. The effect of the regulator-pin continuing its motion to the right' is to push the lower end of lever T into contact with head 26 ofthe pin or stem 25, whereby the valve 21 ,is opened against the action of spring' 22 and air passes by pipes 19 and 20 to the wheel-chamber, thus 'v destroying the vacuum and opposing suicient resistance tothe rotation of the turbine-wheell 2 as to properly reduce its speed.

lt will be obvious from the foregoing-that inasmuch as the valve 21 is open against the action of spring 22 the effect of the spring22` is to move the valve 21 back to its `seat whenever the regulator-pin 16 is retracted. This occurs of course when the speed ofthe turbine becomes reduced by the resistance ofthe admitted air and when, as already stated, the

pin 16 will be moved inwardly orto-the left by the action ot' the regulator-spring 37. As

soon as the airwalve 21 isl closed the steam leakage at the throttle 'continuing will again speed up the wheel, and again the pm 16, moving to the right, will open jthe' air-valve- Ito 21 to admit air to reduce that speed. Thus the action of the device will always take place comformably to the rate of speed ofthe turbine-'that is to say, as the speed increases the air-valve will be opened and as the Vspeed correspondingly d creases the air-valve'wll be closed. t will e apparent therefore that the air-valve control, both in opening `and closing in the manner stated, serves as a'regulator for the speed of the wheel through its` governingof 'the amount of air admittedjto the vacuum-chamber.

1. I'n combination with a steam-turbine and a vacuum-chamber inclosing the same, a valve constructed and arranged to admit air into said chamber and means for actuatingvsaid valve. f

2. 1n combination with a steam-turbine and a vacuum-chamber inclosing the same, avalve constructed and arranged to admit air into said chamber and mechanism communicating with said turbine and controlling said valve to open the same to admit air into said chamber when said turbine shall have attained a predetermined speed of rotation.

3. ln combination with a steam-turbine and a vacuum-chamber inelosing the same, a throttle-valve, an air-valve communicating with said vacuum-chamber and means actuated by said turbine for closing said throttle-valve and subsequently opening said air-Valve.

4. 1n combination with a steam-turbine, a speed-regulator therefor, a throttle-valve controlled by said regulator, a vacuum-chamber inelosing said turbine, and avalve for admitting air into said chamber; the aforesaid parts being` oonstruetedlandiarranged so that the speed of rotation of said turbine beyond aeer- 2O tain fixed rate shall cause said regulator to shut said throttle and open said air-Valve.

5. In Combination with a steam-turbine, a speed-regulator therefor and actuated thereby, a throttle-valve controlled by said regulater, a vacuum-chamber inolosing said turbine and a valve for admitting air into said chamber; 'the aforesaid parts being constructed-and arranged so that said regulator at a certain speed of rotation of said turbine shall operate to elose the throttle, and thereafter at a certain higher speed of rotation of said turbine shall operate to open saidv airvalve.

6. In combination with asteaIn-turbine having a Vacuum-chamber inclosing the same, a

speed-regulator for said turbine having the pin 16, a throttle-valve controlled by said regulator, hollow bleek i8 eomnninicating with said Vacuum-chamber and means for opening the air-valve 2,1 constructed and arranged to be actuated by said regulator-pin 16.

7. In combination with a steam-turbine and a vacuum-chamber inclosing the same, means for admitting air into said chamber, and means for regulating said air-supplyeonformably to the speed of rotation of said turbine.

8. In combination with a steam-turbine and vaeuum-ehamber inelosing the saine, a valve constructed to admit air into said chamber and means controlled by the rot-ation of said turbine for regulating the opening and closing of said valve.

9. In combination with a steam-turbine and a vacuum-chamber inclosing the saine, a valve constructed and arranged to admit air into said chamber; a spring arrai'iged to retain said valve in closed position and mechanism conimnnicating with said turbine and controlling said valve to open the same to admit air into said chamber when said turbine shall have attained a predetermined speed of rotation.

In witness whereof I have hereunto signed my name in the presence of two subscriliiing witnesses.

GEORG OSCAR )[GNUSOLSSON.

Witnesses:

VALDEMAR BOMAN,

N FRITZ Foiessnae.

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