US902797A - Steam-turbine. - Google Patents

Description

J. ATKINSON.

STEAM TURBINE.

Patented Nov. 3, 1908.

APPLICATION FILED JAN.16,1908.

UNITED .miritslrriiixsox, or MELLOR, ENGLAND.

sTE Arr-TURBINE.

Specification of Letters Patent.

Patented Nov. 3, 1908.

Application filed January 16, 1908. Serial No. 411 .150.

To all whom it may concern:

Beit'known that 1, JAMES ATKINSON, a

subject of the h'ring of Great Britain and Irelan'd,'and resident ,of Mellor, in the county of 5 *Derby, England, engineer, have invented certain new and useful Improvements in Eiteam-Turbines, of which the following is a spec'iication.

' 'lhrs invention relates to improvements in steam turbines and particularly to those havinga plurality of or multiple stages of er; ansion and whether of the reaction or impu se type, the ob ect being to provide means 1 or governing them and for controlling the action-of the workingfluidin such a manner that a portion of the latter may be rem- I ployed in conjunctionwith the further supply of fresh or boiler steam, after given out a portion of its energy thereby reducing the total amount of steam formerly required to be generated for developing a given power in the turbine.

Prior to the date of my invention various governing the j :5 power and speed of steam turbines, a common arrangement being to throttle the steam i f 1 at lighter loads and being wiredrawn methods have been used for admission. This is largely used because. 0

its simplicity boiler pressure and that at which it enters the turbine, this drop being very largely Wasted so far as'power production is concernec'l. I utilize this drop oiipressure in the :15 fresh steam and by means of dneyel' a plurality of suitable injector nozzles, arranged and adjusted to suit the conditions of wor z- 1 mg at the time, draw partlally expanded I from 1 steam back, from the turbines say, 40 about midway between the in-lctand the exhaust, and force it into combined with the fresh steam. thus drawn back is hereinafter called the indu'ced steam'and as it adds to the volume of i .S'the total steam'passing reduces the amount of i as already st ated.

through .the earlier stages of the turbme it fresh steam required.

Turbinesmay also be specially constructed to work under average conditions with reduced inlet pressures and considerable quantities of induced steam,

high boiler pressure being economically-elm ployed expanded induced steam while inlet pressure makes it possible to run economically at lower speeds or with fewer it has to the rotor although itis well known that 1 it causes considerable loss on medium or; 30 light loads owing to the drop between the g the turbine again l The steam the relatively in raising the pressure of the partiallyj stages in the turbine. As'the earlier stage of such turbine would have a larger area than in turbines as ordinarily constructed, the blades would be longer and there would be less leakage.

To enable my invention to be clearly understood ;.l. append a sheet of drawings in which a Figure 1 shows steam diagrams illustrating the princi' le of working and Fig. 2 a turbine in vertica section constructed in accordance therewith.

In the steam diagrams shown in Fig. 1 the toes of the diagrams are not fully shown, port-ions being broken outso that the rest may be on a larger scale. The large sized diagrams at c (1 represent the amount of ower in a certain weight of steam at a pressure of 165 lbs. per square inch absolute, expanded down to a low pressure, say 1% lbs. absolute. If this steam wasadmitted atfull pressure to the inlet of, say, a Parson i type of turbine it would represent the theoretical energy in this weight of steam. The other diagrams show smaller weights of steam admitted to the turbine when running at ad mission. For instance, if the wei ht of steam is throttled down to one half, the turbine running at a correspondingly reduced load, theinitial pressure at the inlet wnild probably be in the neighborhood of 100 lbs. absolute and an amount of energy represented by the area of the biur-sided figure a if c a would be almost entirely lost so far as power production is concerned and a e c (1 shows the available power left.

If the fresh steam is passed through a suitable injector noz 'zle or-nozzles, adjusted I in relation to a properly steam nozzle, l'iaving a communication with the turbii'ie sit a place where the steam has been expanded to, say, 20 lbs. absolute, a certain amount of induced steam can be drawn out of the turbine atthis place, raised to the 100 lbs. and again forced into the turbine to assist in driving it. The amount of the induced steam so (.lrawn back is repre- 3 sented by the line 71" 5;", when at 20 lbs. pressure, or by the line 6* 1 represents energy recovered by the injector action of the steam falling area a b 6 a owing to eddy and friction 1 losses 1n the nozzles.

constructed induced The greater the ef-- f? at the 100 lbs. prese, sure, and the four-sided figure'e j flit" l'rom the lbs.

the reduced I to the 100 lbs, being, of course, less than the,

ficleney of the nozzlesgliowever, the more nearly the area of 6 g 71- will approach to the areaa b e a and the larger t e proportion of otherwise wasted energy'recovered.

The other diagrams in Fig. l show other proportions of fresh boiler steam throttled down when admitted to the turbine in the one case, or the energ available for drawin in induced steam and the volume of induce steam drawn in in the other case. I It must be understood that the various pressures 1 and quantities are necessarily only approximate. I

My invention may be applied to any kind of turbine either of the reaction or of the impulse type, so long as it has more than one stage of expansion or to, turbines as ordinarily constructed, say to one of the Parson ty e, in which the greater loads and overload are carried by admitting full boiler pressure initially to the blades of the turbine, with perhaps a by-pass' for the greatest loads; the initial pressure decreasthis arrangement the fresh steam at full boiler pressure enters at '5 passes down through the movable nozzle Z arranged in the casing 11., which in conjunction with the fixed inner cone m, causes it to issue in a regulated circular jet, at n which induces steam from the turbine at is through the pipe connection after it has done some work and is partially expanded, raising its pressure and causing it to reenter the turbine at the inlet 3', mixed with fresh steam; the pressure of the mixture being re ulated by the position of the movable nozzle l, which in its lowest position admits full boiler pressure through inlet 7'. I

- The relative adjustments of the nozzles may be made by hand, more particularly in marine turbines, or by means of any suitable governor u, with or without a relay power or moving the somewhat heavy parts which may in some instances be necessary. The inner cone m may be adjusted to suit the best conditions of working by means of a suitable distance washer r.

More than one set of nozzlessuitably disposed may be used in a turbine, more particularly if of considerable size.

Turbines of the Parson type very commonly have the rotor constructed with three diameters, a small diameter at the high pres-- some"? They can, however, be satisfactorily constructed on this principle with one diameter only, as owing to the low initial pressure the i rings of blades at the high pressure end are with these turbines,

not required and those on the intermediate diameter, having a greater volume of steam passing through them, require to be increased in area, consequently they may conveniently be increased in diameter and made the same .sure end, anintermediate' diameter and a large diameter at the low pressure end.

as those at the low pressure end. Owing to I the reduced number of stages required, the turbine is considerably shortened and as the rotoro may be constructed of one diameter,

requiring only one balancing piston 8, the

so I

cost of construction is materially reduced.

For the same reason smaller or slower-rune ning turbines can be economically constructed, the increased area through the earher rings of blades making it possible to use longer blades so that leakage loss is reduced.

1n marine turbines it is very usual to employ a high pressure unit working with one or two low pressure units. In such instances the induced steam may be taken from the.

system, say, after passing through the high pressure unit, or it maybe taken from part way along the low pressure unit or'units. In turbines of one or of several units also, it may be drawn from the system at any desired stage of ex ansion.

It is not desirable'to' take the in need steam from the turbine too late in the expansion as this would necessitate large connections and the lIlJGCtOI nozzles might not be so efiicient, on the other hand it should not be taken too early as it would not have been expanded sufficiently to have allowed it to have given u much power before being withdrawn. W en applied to turbines working non-condensing the induced steam may be taken from the.

It will be understood that with exhaust. this system a greater weight of steam will usually be passing through the high-pressure portion than through the low ressure or tion, as however, it is frequent y difiicu t to get as much area through the low pressure as might be desired, no disadvantage will arise from this cause.

Very high boiler. ressures may be used t he turbines themselves operating with a moderate range of pressures and not requiring to havean excessive number of stages, thus obtaining the economy' due to the higher pressure without incurring the usual disadvantages.

For marine purposes the turbines can be conveniently and economically regulated for speed or power and special cruising turbines for slow speeds may not be required. They could alsobe used in lower speed vessels than those to which the dpresent type of turbine is practically confine The induced steam may be dried or heated through t 1e turbine.

What I claim as my invention anddesire to secure by Letters Patent is v 1. In a steam turbine, the combination, with a cylinder provided with a conical and annular inlet-passage terminating in a jetpi e which is connected to the portion of the cy inder in which high pressure steam is used;

of a pipe connecte at one end to another portion of the said cylinder in which partially expanded steam is used, said pi e being connected at its other end with the mlet end portion of the said conical inlet-passage, a su ply-pipe for high pressure steam, a no'zz e operatively connected with the said sup lypipe and having its outlet end arrange in the said conical 1nlet-passage, and means for sliding the said nozzle longitudinally of the said conical inlet-passage to adjust the ratio of high pressure and low pressure steam supplied to the said jetpipe.

1 2. In a multiple-stage steam turbine a variably-adjustable injector nozzle located I the turbine cylinder an induced steam pi e connectionfrom the cylin r to the nozzle, 8. spindle cou led to the movable part of the injector nozz e and means for mechanically connecting the injector nozzle with a governor operated from a suitable part of the ordiin the steam inlet and communicating with nary turbine mechanism substantially asand for the purpose described.

3. In amultiple-sta c steam turbine consisting of a plurality 0" units, a variably-adjustable injector nozzle located in the steam inlet and communicating with the turbine cylinder and induced steam pipe connection between any one of the units communicating with the injector nozzle, a spindle coupled to the movable art of the injector nozzle means for mec anically connecting the injector spindle with a governor and a governor operated from a suitable part of the-ordlnary turbine mechanism substantially as and for the purpose described.

In testimony whereof I have hereunto set my hand in the presence of two witnesses.

. JAMES ATKINSON Witnesses:

WILLIAM -HENRY TAYLQR, AMY E. Evrns.

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