US815155A - Turbine. - Google Patents

Description

' 11. 1". FULLAGAR.

T'URBINE.

APPLIGATIONTILD 11:11.17. 1905.

j@ 72. fully@ PATENTED MAR. lf3, 1906.

2 SHEETS-s112311.

"To all whom t may' eqneerfn:

UNI-'iran srarnes PATENTN OFFICE.

HUG-n FRANcis .FULLAeAn or NEWcAsrLE-UPoNfTYNn ENGLAND,

vASSIGNORTO ALLIS-CHALMERS COMPANY, OF JERSEYy JERSEY, A CORPORATION OF NEW J ERSEY.

TURBINE.

Beit known that I, HUGH FRANCIS FUL- LAGAR, asubject of the Kin of Great Britain and Ireland, residing at vewcastle-u on Tyne, in the county offNorthumberland, ng-

.land, have invented Improvements in Turbines, of which the followingis a specification.

In axial-How turbines, which have several sets of rotary and stationary blades and in Which the rotary blades are mounted upon a stepped shaft or drum (hereinafter called the spindle `or rotor,) increasing in diameter from the inlet to the exhaust, it is usual, in

order to balance the end thrust of the steam or other working fluid,y (hereinafter referred to as steam,) uponthe rotary rings of blades and annular surfaces ofthe steps of the spindle t'o provide the spindle at its inlet end" with similar but reVersely-arranged steps the diameters of which correspond to those of the main or Working steps carrying the rotary v rings of blades plus an amount corresponding of` blades Wit 30 usually to the radial length ofthe blades in the rings of blades upon those steps or to the mean radial length of the blades in the rings ofblades Where several rings of blades of different length are used on each step, the ref versely-arran ed steps bein provided in lieu ordinary layrinth p'ackin devices, thus forming what are usually calle balanceepistons, so that the end pressure of the steam upon the annular surfaces of these balancing steps or pistons is equal to and counterbal'ances the steam-pressure upon the first-mentioned steps-v and the rotating rings of blades carried thereby.` In order toinsure that the pressure of steam upon the corresponding Working and balancing steps shall be exactly equal during the working of the turbine, the parts of corresponding diameter of the tWo sets of steps are 'connected by pas# sa es or`ports,the outer 'side 'of the largest `ba ance-piston being connected with the eX- 4haust. VVlth this arrangement, however, as

the balance-,pistons have to be lmade of diferent diameters that are dependent upon and kkapproximate to the different diameters of the rotary rings of blades in the corresponding g -4 sets thereof which they are designed to counterbalancei or` upon the mean diameters of the rings of blades in the several sets Whenthe rings of blades. in each set are of varying Specification' of Letters Patent. Application filed Febrnaryl', 1905. Seria1Nu.246.125. Y,

-rear or pressure end of which' is connected vto flow of steam from the piston-chamber to the Thisarrangement enables the diameterffof f The turbine-spindle diameter, it follows that the turbine -casingl stepsaya andl c. --To twofof these cirY, lNEW Patented March 13,1906.

or stator has to be made of a stepped shape to'accommodate the balance-pistons, 5 5 and. When therey are a number of such pistons the casing at the corresponding end of the turbine has to'be made of considerable diameter vto accommodate the outermost and largestl bala-nce piston, which is objectionable in ractic'e. To obviate'this, accordingtotliis invention a balance-piston is proyid'ed at the exhaust end 'of the turbine-spindle adjacentr to and inside .the outer Walls of the exhaustchamber between it and the last set of turbine-blades. j l n In .one arran ement I remove'the largest balance-, iston from the spindle at the inlety end of.`t e turbine and attachit theretoat the exhaust end at apart thereofadjacent to and inside `the outer end wall of the 'exhaustchamber located at the outlet end'ofthe: last and largest set of rings of bladessuchbal ance-piston beingl arranged in a, chamber the the steamspace between the tivo last bladed steps of thel spindle, ,thev usualV labyrinth packing being-provided'l between the piston and thewall ofthe chamber to'retar'd the exhaust-chamber. The front or .exhaust end of the chamber containin the `balancepiston of next smaller size and vK ocatedlat the inlet end of the turbine is connected, as usual, to, the steam-space betweenfthe two 'last bladed. 8 5 steps of the spindle, Whlexthe steam-space between the two irstbladed steps'of the spindle is connected to therear or ,pressure side of said next smaller balance-piston.

a and `b--there correspondbalan i sa and e, provided with labyrinth packingdevices d and e of ordinary type, the pistons d and e being arranged on the opposite side of the steam-inlet f of the turbine-casin g to the bladed steps a and'b, and the adjacent end surfaces ofthe bladed step c and the piston d being in direct communication, while the adjacent end surfaces ofthe bladed step b and the piston e are in communication through a pi e or passage e2 in the usual manner. T0 ba ance the end thrust on the inlet endl of the bladed step c instead of a balanceiston arranged as an annular ste of larger iameter than the iston e and at t e farther side thereof from t e bladed steps a, b, and c, there is employed a piston 7L, separate from the piston e and placed in a space or chamber i at the exhaust end of the bladed step c, that part of the space or chamber i that is farthest from the step c bein in communication with the steam-space j etween the last two bladed steps b and c of the spindle throu h symmetrically-arranged assages 7c, extenin through the spindle an the piston, so that 51e rear end surface of the latter is subject to lthe pressure of the steam in the said space j. The front end oi the space or chamber m containing the balance-piston e at the opposite side of the steam-inlet j" is shown in the-illustrated example in communication through the pipe n with the steamspace j between the two last-bladed steps of t e spindle. The space or chamber t containing the balance-piston 7L is separated labyrinth packing device 7L from the exhaust-space 0 by an ordinary between the piston h and the inwardly-projecting wall i of the said space or chamber i. g q are glands vbetween the ends of the turbine-casing and the spindle.

Turbines constructed according to this invention. have advantages over those of previously-known construction. For instance, they are more compact and loss of steam and power is reduced, since it is possible to employ `ner clearances upon small balance-pistons than can be used with small ones, both because any deviation or vibration oi' the spindle causes a greater variation of clearance the larger the iston, and also because such4 large pistons, iaving a highrperipheral velocity, are liable to cause serious damage if they should come accidentally into hard con- 'tact with the part of the casing or cylinder that surrounds them. Also, owing to this high peripheral velocity,the unavoidable presence of water in the packing-grooves causes very considerable friction and loss of power` Other advantages are that one equalizingpassage in the casin or cylinder can be dispensed with and bot the glands g g are subject to about atmospheric pressure.

The details of construction may be alt-ered without departing Ifrom the essential features of the` invention.

1. In a turbine,the combination of n bladed casing, a bladed spindle located therein, balance-pistons located in separate chambers having separate exhausts, and each adapted to balance a portion ol the endwise thrust on the spindle due to fluid-pressure, one of said pistons being outside the exhaust-spare.

2. ln a turbine,the combination of a blnded casing having an inlet for motive fluid and :in outlet for exhaust, a spindle located within said casing and' provided with groups oi' blades' fixed upon portions of said spindle ol' different diameters, a balance-piston tor eneh group of blades, the balance-pistons for the several groups, except that for the group upon the largest portion of the spindle, being o dilierent (.liaineters and arranged in :i chamber that is common to them, is of difierent diameters to suit the pistons, and is in communication with the interior of the casing at different parts thereof so that each balance-piston will be subject to theaetion of motive fluid of the same pressure as that to which the corresponding group of blades is subjected, and the balance-piston for the group of blades upon the largest portion of the spindle being arranged in a chamber that is separate from that containing the other balance-pistons, has a separate exhaust, and is in communication with the interior of the casing at a part thereof between its ends.

3. ln a turbine,the combination of a bladed casing having :in inlet for motive iinid and an outlet for exhaust, a spindle located within said casing and provided with groups of blades fixed upon portions of said spindle of different diameters, a balance-piston for each group ot blades, the balance-pistons i'or the several groups, except that for the group u on-the largest portion ot' the spindle, being oi diiierent diameters and arranged in a chamber that is common to theu'i, ot diil'erent diameters to suit the pistons, and is in communication with the interior of the easing at different parts thereotso that eaeh halanee-pislon will be subject to the action oll motive lluid oiE the saine pressure :is that to which the eorresjionding group of blades is subjected, and the lnilance-piston lor the group of blades upon the largest portion of the spindle being arranged in a chamber that is separate from that containing the other balance-pistons, is upon the opposite side ol' the outlet-space to theblades and is in coinniunication with the interior of the casing at a partthereof between its ends.

4. ln an axial-flow turbine, the combina tion oi' a bladed casing or stator having an inlet-space and an exhaust-space, a spindle or rotor within said casing, blades and balancepistons upon said spindle, one oi' said pistons being at the inlet end of the turbine and another at tbe exhaust end ofthe turbine at the exterior portion of the exhaust-space, and a llO IIS

passage through the rotor connectin the exterior side ofthe balance-piston Wit the in'-,

terior chamber of the turbine to furnish fluid under pressure thereto above the exhaust- '5 pressure, substantially as described.r` 4

' 5. In an axial-flow turbine, the combination of a bladed casin or stator, a bladed spindleor rotor locate therein, anexhaust- C.

` lamber arranged between the bla'dcd spinxo dle and one end wall ofthe casing or stator, a

balance-piston upon said rotor arranged between the exhaust-chamber andthe end`wall' of the casing7 a balancing-chamber between i said. balance-piston andthen end Wall of the 15 casing, and a passage through the rotor connecting the interior ofthe casing with the bal-f :Lucini-chamber,'substantially as described. 6. bla-ded turbine havin avsinglebal- Aance-piston spaced from the laded portion 2c near the -10W-pressureend, "and other sepa- 'ratemeans for balancing.

7. VA turbinehaving in the outer side'of its i exhaust-chamber a single bala'tnce-piston7 and f other independent means for balancing.

8. A chalnbered 'support,.a blade rotor 25 pressure balance-pistons thereon, means of communicatlon from a chamber to one pls'- ton and from the same lchamber separate means of connnunicationlto a second piston, one of the pistons being spaced Ifrom the blades.

9. A chambered support, a rotor, pressure y l this {Lthday of February, 1905.v l y :HUGH'FRANCI'S FULLAGAR. l Witnesses:l

H; SCOTT. 5

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