US895644A - Turbine. - Google Patents

Description

- .-IINITED STATES PATENT OFFICE.

ALEXANDER IUDE, OF BIRMINGHAM, ENGLAND, ASSIGNOR TO BELLISS & MOCOM'LIMITED, OF BIRMINGHAM, ENGLAND.

TURB INE Specification of Letters Patent.

4 Patented Aug. 11, 190s.

I following is a specification.

This invention relates to turbines for eX- ansible fluids, the principal feature of which is the, employment of im roved constructions and arrangements for o taining a balance of the fluid-pressure forces on the rotor in the direction of its aXis of revolution, the rotor being entirely or partially of drum forma.

tion.

".The system of balancing to which the improvements,.which -form the subject of this application for a patent, are applied may be described as that in which the flow of the stream of operating fluid along the length of the rotor is, in the initial port1on of its path, in one direction and in the terminal portion in the opposite direction.

For convenience in reference it will be advantageous to give this system a name, the name adopted being fthe to and fro balance system, this system being distinguished from that other s *stem of balancing in which, by the du lication of the operating organs, one half t ie stream flows infone direction and the' other half inthe opposite direction. In such a to and fro system the iluidma be admitted to the rotor at some interme iate portionv of its length and, after flowing in one direction to the end of the rotor, the fluid will be required to be con'- veyed along a` passage, this being an inactive portion of its path, and admitted to other oerative organs of the rotor to traverse t ein in the opposite direction .to the second end of the rotor. Alternatively to this, the fluid ma have an inverted direction of iiow, being a mitted at one end of the roto'r and caused to finally escape from the rotor at an intermediate portion of its length. Certainl important advantages over the former accompany such an inversion of flow as will be presently explained. One oi m improvements consists in conveying the uid, 1n the inactive portion of its path, through thel in-v terior of they rotor instead of along a passage formed in or added to the statorz-Also'to obtain, convenienti abalance of the forces, by the to and fro system above described,

when a large range of expansion is employed, I find it very advantageous, in the initial stage of the fluid action, to employ adiskwheel of relatively large diameter, in the subsequentsta es a drum or drums being emi .ployed for t e body of the rotor. By means ters of the successive which are requisite to ring about a balance of the fluid pressures, will also-permit of appropriate peri heral speeds, also, by the same means, t e tendency for the fluid to leak past the shaft at the two ends of the stator casing or from one section of the casing -to the other will be minimized.

The invention includes also al special method of mounting the rotor on the shaft and securing it thereto, to minimize the stresses and strains which may arise from differences of temperature and to facilitate the assemblyv of the parts of the rotor.

Besides the advantage of avoiding the employment of balance pistonsor, the alternaL tive, namely avoiding the duplication of the operative organs of t e turbine, the to and fro system of balancing, adopted in this invention, lends itself to the obtainment of important advantages inrespect to the reduction of the leakage of air into, and steam or other fluid from, the stator casing at the ends through which the shaft emerges. l

Supposing steam to be the fluid employed, then, by the adoption of suitable proportions, it will, particularly when the disk-drum combination is employed, be easy to arrange for the pressure at one end of the casing to be slightly in excess of the atmosphere, thus avoiding the possibility of the entrance of air and minimizing the liability to the outward leakage of steam. By a known contrivance, the advantage of a like pressure at the other end of the casing can be secured when the above mentioned inverted direction of flow is ado ted.

references, the above mentioned flow arrangement will be named in at end-out at middle type and the alternative will correspondingly be named in at middle-out at en( type.l

To minimize the loss .by leakage from one section ofA thecasing to another, I employ my device for utilizing leakage steam as described in the specification of my patent application #330585, Series 1900.

Reierring to the accompanying drawings of such a disk-drum combination the d iameortions of the rotor,

To acilitate description and shorten the Figure l is a longitudinal section of a turbine of the in at embout at middle type with inactive flow Within the rotor and vwith the disk-drum combination', and containing also the device for making the pressure at both ends oi the stat or casing equal te one another, the pressure at those ends being arranged to aiproxii'nate to that `r of the atmosphere.

igs. 2 and 3 show details of Fig. 1. Fig. 4 is a part longitudinal sect-ion of a turbine, Which'also. is of the in at end-out at middle type but without the disk-drum combination. Fig. 5 is a longitudinal section of the same type in respect to the direction oi' flow, in which the disk-drum combination is employed but in' which the inactive flow takes place `through a pi e secured to the stator instead of passing tnrough the rotor. Fig. 6 is 'a longitudinal section of a turbine of the in middle-out atend type with inactive How Within the rotor and with the disk-drum combination. Figs. 7 and S' show details of Fig. 6 and are alternative to those of Figs. 2 and 3. Fig. 9 is a part longitudinal section of a turbine, also of the Hin at middle-out at end type but Without the disk-drum combination, and :-Fig. 10 is a longitudinal section oi'another turbine of the in at middleout at end type in which the disk-drumv combination-is employed but in which the inactive 4i'lovv takes place through a pipe secured to the stator.v

Referring `to Eig. l the i'iuid is admitted through the branch c to nozzles which direct it to impinge on vanes secured to a diskF Wheel Zi. TW sets of vanes on the Wheel b are shown, With intermediate guide blades secured to the stator,.whereby tie very considerable kinetic energy of the iluid derived by a drop of pressure oi, or about, one-half the initial pressure can be efficiently utilized.' In this first stage of the action, the construction and arrangements are such that the pressure in the spaces c and d on the two sides of the disk-Wheel b is the same. From d the fluid flows past a series of vanes secured to the drum portion cof the rotor, which vanes are alternated with the guide blades or nozzles With partial admission which are se cured to the stator.

At f there will be a reduced pressure and the expanded iiuid will be caused to How past another Valternated series of nozzles and `va es, the latter being secured to a drum pori n p of the rotor. On arriving at lzy the iiuid Wil have fallen to a still lower pressure and Will then be conducted through the interior ofthe drinn-portion@ of the rotor pastlhelically shaped Webs formed in rings j and 7c (Figs. 2 and 3) Which-su )port the portion fi of the rotordrum- The ow throught' will. be inactive as tar las the production of mechanical energy is concerned.

On emerging from iuto the space m the iuid will be directed to i' turn along the outdisk-Wheel b and the initial stage ence between side of the drum/i past a further' alternated series of nozzles and vanes, at the. end of Whih it Will enter the space n divested as fully as possible of pressure and velocity head,

In the vspaces 7ay and n there will be a diii'er ence of pressure which will tend to cause a leakage offiuid past the separating diaphragm o. To minimize the loss thereby and at the same time avoid irictional contact ot` rotor and stator l may .adopt my guide blade and vane system of utilizing leakage fluid as described in the specification of' my patent application #330585, Series 1900, or I may use any other known method of lcssening the leakage of fluid past aworking joint.

1f steam is the operating fluid and a `condenser is employed, then, by the adoption of suitable proportions it Will be possible with this direction 'of loW along drumrotors on the to and fro system to obtain an approximate longitudinal balance of the fluid lforces on the rotor and atL the same time to maintain in the space m a pressure nearly equal to that of the atmosphere, )referably a little in excess, to avoid lthe in 0W of air past theshaft and the impairment of the vacuum in the condenser.

In the space c at the other end of the stator casing the fluid pressure will still be considerable, though very much loss than the initial pressure. To eliminate leakage of fluid past the shaft at this end of the easing the following already known device may be employed.

Beyond the s ace c a small chamber p is provided into W ich the fluid may leak from c, the loss being minimized by the employment here also of the before mentioned contrivance of patent application #330585, Series 1900, or other method of lessen'ing leakage. To connect the chamberp and the space m a pi' e g is provided through which the leakage uid wil be passed to join that Which emerges {roma} and 'be conducted past the Inozzles and guide blades outside the drum i thus assisting in driving the turbine.

The iiuid pressure in m being approximately atmospheric, as before described, thel trouble of leakage of Huid past the shaft may thus be avoided at both ends of the casing.

ln the construction shown in Fig. '4 the action are omitted. l

According to Fig. 5 the construction and operations up to the space h' are the same as in Fig., l and so also after-the fluid has reached the 'sgace m, the distinctive diler means'fcr providingthe inactive passage of the fluid trom 7L to m, a pipe Ir being provided 'for this purpose in the constructionshown in Fir.

Figs. 0 and 10 show examples of the gs. l and 5 consisting-in the' rio of the fluidv` drums e1 g1 to the space m1.

I veyed in at middle-out at end typehof balanced turbine. In Fig. 6 the fluid 1s admitted at a1 to a wheel b1, and flows from d1, in a direction from right to left, along the vanes of the drums el 'and g1 to the space h1 from which it passes inactively through the interior of the From m1 the fluid flows in a direction from left to right along the vanes on the drum i1 and emerges at the end of the rotor into the space nl from which it is finally evacuated.

In its inactive passage within the rotor it flows through holes which are bored obliquely through the web plates of the rings y and k1 (Figs. 7 and 8) which su port the ends of the compound'drum e g. s in Fig. 1 the pressure in the s aces c1 and d1 on the two sides of the whee b1 are alike. In the space c1 the pressure will be greatly in excess of that in mlon the other side of the separating diaphragm o1,` the dierence in the two pressures being much greater than on the two sides of the corresponding diaphragm o of Fig. l. Means for minimizing the loss by leakage are employed as in Fig. 1 but the loss thereby will necessarily be greater than in the in at end-out at middle type. Also, supposing steam to be the operating fluid and a condenser emplo ed, there will be a vacuum in the s ace nl W ich will tend to cause a leakage o air past the shaft and so impair the vacuum. Accordingly in this respect also, the in at end-out at middle type has an advantage.

Fig. 9 shows, in part view, a corresponding construction but with the disk-wheel omitted.

Lastl- Fig. 10 shows how the Huid is confiom the space h to the space m1 along a pipe r1 outside the rotor. Also in this ligure the separating diaphragm o1 is shown embracing a somewhat large boss s of one of the end plates of the drum il. The boss s constitutes virtually a balance piston and the construction shows how the two systems of balancing may be combined. "In t is case the piston device is employedftocompensate for a minor difference of the forces on the rotor instead of being required to balance the entire ormajor force of the fluid pressure as ordinarily employed up to the present.'4 Also. in Fig. 10 is shown a special method of mounting the rotor on its s aft. According to this, the wheel b1 'and the bosslate s areboth made to tightly t a tapere plate s an a second boss-plate u, at the other end of the drum il, a sleeve fu is interposed.' The portion wof the shaft is screw threaded ortion t 0f the shaft, between the and, by means of a nut x, the boss of the wheel b1 and the plate s are forced tightly on to the tapered ortion t of the shaft, no key being employed) at this is fitted to secure the osslate u to the shaft and another at the ot er end of the rotor. The plate u is made thin enough to be sufficiently flexible to yield and compen-4 sate for differences of temperature drum and shaft.

I claim:

'1. A turbine comprising a stator, a hollow compound rotor consisting of a disk wheel and drums, means for introducing .the operating fluid to the operative surface of the rotor, means for causing'the whole of the fluid to flow in one direction along a portion of the length of the operative surface of the rotor, means for causing the whole of such fluid to flow in the reverse direction along another ortion ofthe length of the operative sur ace of the rotor, and to reach that portion alone the hollow body of the rotor, and means for conveying such fluid away from the turbine.

2. A turbine comprising a stator, a compound rotor consisting of a disk wheel and drums, means for introducing the operating fluid to the operative surface of the rotor at one end thereof, means for conveying the whole of such fluid away from such operative surface at an intermediate portion of the length of the rotor and means for reintro i ducing it to the operative surface at the -other end thereof, and means for conveying such fluid away from the turbine at en inter-- mediate portion of the length thereof.

3.' A turbine comprising a stator, a hollow compound rotor consisting of -a disk wheel' and drums, means for introducin the operating fluid 4to the operative sul ace of the rotor at one end thereof, means for lconvey- 100 ing the whole of such fluid away from such operatwe surface at an intermediate portionl o the length of the rotor and means for rel introducing it to the operative surface at the other end thereof, comprisin suchfluid away from the turbine at the in termediate portion of the length thereof'.

lIn testimony whereof I have signed my name to this specification in the presence of 1re two subscribing witnesses.

ortion though one A the hollow 105 body of the rotor, and means or conveying

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