US938309A - Elastic-fluid turbine. - Google Patents

Description

S. Z. DE FERRANTI. ELASTIG FLUID TURBINE.

APPLICATION FILED MAY 20, 1907.

Patented Oct. 26,1909.

. 5e bowfiian Z deferrantzl, ,By IMIL M #151104,

uurrun 4 s'rarus rAjT NT OFFICE.

SEBASTIAN ZIANI DE FE IB IR'QANTIpOF GBINDLEFORD, ENGLAND.

ELASTIC-FLUID. TURBINE.

To all whom it may concern:

' FERRANTI, a subject of the King of Great Britain and Ireland, and residing at Grindle-- ford, in the county ofDerby, England, have invented certain new and useful Improvements Relating to Elastic-Fluid-Tur'bine Installations, of which the following is a specification. v

My invention relates to condensible elastic fluid turbine installations and has for its object to provide-improved feed heating arrangements which shall effect a substantial increase in the efliciency of the plant. V

In such. power installations for marine propulsion purposes, for example, it is com- 'mon practice to pump the feed water direct from the hot-well into the boiler but as the water so introduced is at the same temperature as that of the hot well, it is evident that a considerable increase in the efliciency of the plant could be effected if the temperature of the water before entering the boiler could be raised to a point at.or near the temperature of evaporation corresponding to the working pressure of the boiler. According to my present invention I attain this result in an economical manner in turbine installations for either land or marine work. 3

My invention consists broadly in an elastic fluid turbine power installation in which the feed is heated in a considerable number of stages as it pro resses toward the elastic fluid generator y quantities of working fluid of difierent degrees of expansion abstracted from the turbine so that the more highly expanded fluid imparts heat to the steam from the turbine of different degrees of expansion andutilizing the steam so abstracted to heat the feed water, the more highly expanded steam operating to heat the feed water at a point in the path thereof more remote from the boiler than that at Specification of Letters Patent; I Patented Oct. 26, 1909. Application filed May 20, 1907. Seria1.No.-374,659.

which the less highly expanded steam opcrates.

My invention further consists in the improved power and feed heating installations to be hereinafter described.

In the following description I shall take steam 'as'an example of a suitable condensable elastic fluid throughout.

In order to obtain; the most economical results according to" my improved system of feed heating, the withdrawal of steam at a considerable number of points ofidifierent pressure (say 8 0r 9) should be provided for, since the feed is then heated at each A point by steam only a little hotter than itself and the best conditions for a highthermodynamic efiiciency are secured. A large number of stages, however, means that each stage heater works through only a small temperature difference so that to secure a proper-transference of heat it isimportant during the course of its expansion in the turbine to heat the feed water the volume of steam entering the high pressure end will be much larger than usual Whereas the volume of steam flowing through the low pres-. sure end will be less than usual. The effect of this is that on the one hand, the amount of the clearance loss at the high pressure end can be made less in proportion to the volume of steam passed while on the other hand the ratio of the circumferential to the axial I velocity can be increased at the low pressure end, a substantial increase'in the efliciency of the turbine itself being thus obtained. Further, anything which increases the blade length of the short blades ofthe tin-bine,

increases economy by reducing the proportionate loss due to eddies and friction at the.

end boundaries of the flow spaces. WVhere however, "in order to obtain proper surface speed and tosreduce the relative clearance losses and without any reference to the present invention, "a turbine has been deboiler.

signed, as often occurs, with too large a high pressure end, the mere addition or application of my improved feed heating system will render the proportions adopted as the best compromise under the circumstances tent of a diagrammatic nature and should not be taken as working drawings.

When desirable the same reference symbols are used in the difierent figures to denote corresponding structural features.

I carrying my invention into effect according to one form as applied to a condensing steam turbineinstallation, I provide a turbine, a, (see Fig. 1) of the pressure flow type, for example, and I lead pipes, b, from different stages of this .turbine to a series of feed heaters, c, which may conveniently 'beconstructed after the manner of the ordinary surface condenser, 71. 6., with tubes, 01, adapted as shown in Fig. 1 to transmit heat through their walls from the steam passing through themto' the feed water.

Pumps, 6, arevprovided preferably drawing from the hot-well and forcing the feed water through the heaters, a, in series to the The arrangement is such that the heater which is first encountered by the feed water in its passage toward the boiler is connected to the turbine at a pointfnearest to its low "pressure end while the remaining heaters are individually connected to the turbine in turn at points increasing in distance from the low pressureend so that the feed water is progressively heated on its way tothe boiler. I prefer to arrange the' tubes of such areas. and so forth that th'e' water, and'especially the steam pass through the heaters'at considerable velocity so as to scour the tubes and insure efiicient"transference of heat. v

The water of condensation from the heaters with any admixture-of live steam passing through-the tubes is delivered by pumps,

f, to the main feed water preferably at a point in advance of theheater from which 't was drawn. All the pumps, 6 and 1, may e conveniently driven from one shaft as shown in ,the figure and suitable non-return valves, 9', may be provided asindicatedr The transference of heat to the feed water, is thus effected inathermodynamically efficient manner asthe steam which has given up most of its, energyto -theturbine and l is therefore of lowesttemperature'is placed manner.

so as to give up its heat to the water as it passes'through the first heatenwhile the following heaters and the water condensed in them and pumped back as described above serve to heat the feed water progressively at increasing temperature.

According toa modified form of the invention, (see 'Fig. 2) the heaters, h, are constructed after the manner of jet spray condensers, being connected as before to different stages of-the turbine. A pump, '5, drawing from the hot-well delivers the feed water through any suitable spraying nozzle, 70, or the like into the interior of the first heater where it is brought into intimate contact with the steam introduced from the low pressure end of the turbine.., A second pump, m, of somewhat greater volume than the pump, 2', delivers the feed water thusformed in the firptheater through a similar spray into the second heater and so on, the last pinup-delivering direct to the boiler.

"The feed water is thus heated progressively as above in a thermodynamically efficient As the temperature dilferences are very small for the heat transferred where a large number of heaters are adopted, it is of special importance in such a case to secure v intimate contact of the steam and water over very large surfaces. 4 In cases where the steam finally leaves the rotor on its way to the condenser with a residual velocity and isconsequently at a higher temperature than the hot-well, I pre ferto abstract steam from a oint f the turbine as near the exhaust on as possible or even from the exhaust pipe itself while on the other hand steam should be abstracted from a point as near the high pressure end as possible so as to insure raising the feed water to the highest temperature'available.

Other things being equal it is of more importance to abstract steam from points near.- the ends,- (lithe; turbine than from the intermediate points. j ,3"

When the speed of the turbine is governed by throttling, it is found that even-with reduced loads and s stantial gain in e ciency.

In installations of the type employing a 'regenerator, .I arrange for pumping the water from the hot wellthroug'h the regenerator and impart the balance of heat necessary to bring the temperature of the feed water equal to that of evaporation. in the boiler according to the progressive systemof heat ing hereinbefore described, a corresponding number of heaters being omitted at the low,

pressure end of the turbine; and in, any

other case where the feed water is already partiallyheatd from. any source of waste 'hea't'I may adopt a similar arrangement and add only so much of'the herein described eeds there is stills! Slbv V difference through which the pump has to work is 'reat, as may'occur tor HISULIICG during the last pumping stage when throttle governing is employed, 1 may use two or more rotary pumps in series.

In all cases in order to insure the successful working of my system of feed heating it is of the utmost importance to prevent the feed heaters becoming air-logged and when the heater adopted is not self-clearing as regards the air, suitable spaces should be provided in which the air may accumulate .to-

gether with snifter valves or escape.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is 1. The combination of a condensable elastic fluid turbine; a plurality of feed heaters, said feed heaters being connected to points of difierent pressure in said turbine so as to progressively heat the feed, as set forth.

2. The combination of a condensable elasthe like for its tic fluid turbine, a plurality said feed heaters being connected to points of diflerent pressure in said turbine together with means for passing the feed through the heaters, the feed water being first heated by low pressure fluid and progressively thereafter by higher pressure fluid as set forth.

3. The combination of a condensable elastic fluid turbine; a lurality of condenser feed water heaters, said feedcondenser heat-- 'ers being connected to points of different pressure in said turbine so as to progressively heat the 'feed water as set forth.

l. The combination of a stage turbine and a plurality, of feed heaters-connected to points of difl'erent pressure in said turbine so as to extract fluid therefrom and progressively to heat the feed, said turbine being proportioned from stage -to stage to correspond to the different quantities of fluid passing therethrough p In testimony whereof, I aflix my signature in presence of two witnesses.

' SEBASTIAN ZIANI FERRANTI.

Witnesses: LUTHER J .'PARR, CHAS. N. DANIEL.

of feed heaters,

Images