US1766886A - Gas-turbine unit - Google Patents

Description

Filed Dec. 2, 1924 2 Sheets-Sheet l June 24, 1930. J. w. A. ELLING GAS TURBINE UNIT Filed Dec. 2, 1924 2 Sheets-Sheet 2 Patented June. 24, 1930 arms WILLIAM Anexmus ELLING, or c'nms'rmnra, NORWAY GAS-TURBIN E UNIT Application filed December 2, 1924, Serial No.

The gasturbines of the impulse type hitherto known are based upon the same idea as 7 gas motors with pistons, viz. compression,

combustion and then an extensive expansion. This principle which is very well suitable in piston motors is, however, connected with great difliculties in turbines. If, namely, the efiiciency shall be maintained at a reasonable value the great kinetic energy contained in the gases of combustion before their passing into the turbine wheel must be trans formed into a velocity so high that only with difliculty can it be utllized within the wheel,

because the. latter should not be given a higher velocity than what the materials actually used can safely stand, and the outlet velocity will be very high. In, addition thereto, there are inconveniences in connection with the high temperatures andthe ex;

tra increase in temperature, to which the bl'ades'ar'e subjected. vMoreover, the high velocity of the runner requires gearing in order to enablethe utilization of. the useful work.

The starting will be difficult, and areversal will be practically impossible.

The present invention has {for its object to avoid completely the drawbacks which in the said respects have been'connected with the systems hitherto known and this is obtained'by adivisionof the process into two or more stages and by such an arrangement that .the work-of compression for the last stage independent of the preceedingstages.

or stages is effected substantially by the preceding stage or stages. pendent of one another in mechanical respect,

particularly the last stage, wherein the useful work is taken out, is mechanically quite In orderto enable the invention to be understood,.thesame will be described with reference to the accompanying drawings showing in Figures 1 to 4 diagrammatically a multi-stage system constructed in accord- 1 ance with the invention. Figure 5 shows a modification and Fig. 6 is a 'Rankine-dlagram 'for the, system shown.

In the drawing, Figures 1, 2, 3, 4 represent the different stages, which hereinafter for sake of convenience will be termed shortly I,

II, III, IV. 1, 1, 1 designate gas turbines All stages are inde 753,580, and in mm December 1s, 192a.

and 2 2, 2, respectively, compressors con nppted therewith, and 1 is a turbine of stage I v The air enters the compressor 2 III (Figure 3) and is compressed therein.

Having passed out from 2 the air is cooled at 9 and passes througha co uit 4 to a second compressor 2 forming e element of stage II (Figure 2). 'In the second compressor the air'is further compressed and is thencooled again at -9 and passed through "conduit 4 to a third compressor2 of stage 1 I Figure 1) in order to be finally compressed of stage t 'erein. In this highly compressed stagethe I gas passes into a combustion chamber 3 into which a suitable combustible is sprayed at 10. The products of combustion are now passed through the conduit 5 to the driving turbine 1 of stage I and from there through the conduit 5 into a combustion chamber 3?, into which a combustible is sprayed at 10*, and theythen pass through the turbine 1 of stage II. From the latter the gases are passing further through the conduit 5 to the turbine 1 of stage III preferably without pass-' 'ing through'any further combustion cham- -'ber. The gas expanded in the turbine of stage III may thenbe assed through conduits 5 to a driving tur ine 1, for instance for a dynamo 6, or. to piston motors 7, 7 (Figure 5),

Thecompressors of each stage are coupled directly to turbines and the velocity is control y a separate governor at each stageas indicated at 8, 8

a -Thus the compressor 2 is coupled mechan- .ically to turbine 1 of stage'L-compressor 2 of stage II,yand compressor 2" to turbine 1 toturbine 1 of stageIII, and all these three stages are independent of'each other'in mechanical respect.

By means of the diagram of Figured the operation will be clearly understood; In this rag-ram the abscissas representvolumeof air sure in the ordinary manner. The horizontal .bottom 'llnerepresents the absolutezero-pressure and the next horizontal line above same represents the atmosphericpressure, wherefor the res ective stages Ital,

I and gases, and the ordinates'represent pres- Thus the curve 11-12 represents the usefulwork of compression. The gross work of compression is represented by the curve 11-12', it being assumed that the work 11-12 be 75% of thework 11'-12' corresponding to an efliciency of 75% in the compressor. The air from 2 has a temperature of 104 C. and is cooled at. 9 to a temperature of say 17 C. (12-13, Figure 6). Then it passes into compressor 2 and isfurt-her compressed corresponding to a rise in temperature from 17 to 104 C. The curves 13-14 I and 13'-14 represent the corresponding as compared with the initial pressure (1 at to the temperature (310 'C.)

the outlet from turbine 1".

useful and ross work of com ression respectively. ooling is again e ected at 9' down to 17 (14-15, Figure 6) and then a final compression is effected in compressor 2 from 17 to 104. Thecurves 15-16 and 15'16' represent the corresponding useful and gross work of compression respectively.

'At 10 the compressed air receives heat, whereby its temperature is raised to 490 (16-47, Fi ure 6) and is then'expandedin turbine 1. Ihe curve 17-18 represent-s the gross and curve 17 -18' useful or net work of expansion, it being assumed that the work 17 '-18' is 85% of the work 17-18. At 10" the partly expanded gases receive heat energy and are raised from 400 to 490. A further expansion (from 490 to 400) takes place in turbine 1, the gross and net works of expansion, being represented by curves 19-20 and 19'-20' respectively. From turbine 1* the gases pass directl to turbine 1 in order to be furtherv expan ed (from 400 310 0.), the gross and net work of expan'sion being represented by the curves 20-21 and 20-21' respectively. The gases are now prepared for exerting useful work in the engine 1, having an increased pressure mosphere) before the compression and having also an increased volume corresponding revailing at T is prepared aseous driving fluid can therefore be utilized n any suitable engine, either a fourth turbine 1 for driving the dynamo 6 (Figure 4) or a plurality of piston motors 7, 7 (Figure 5).

As will be seen from the drawing the engine 1 or 7, is not mechanically coupled to the aggregates of the stages I, II, III, but is mechanically quite independent thereof.

Consequently the transferring engine thus ing,

can be retarded, accelerated, stopped and I even reversed independently of the rotating masses of the first three. stages and independently of the working conditions thereof. The manipulation of the engine therefore can be effected very easily and with a reasonable mass, because the rotating masses of the said three stages will in no way take part of such manipulation but can run with unaltered speed and in a constant direction of rotation. Obviously this result is of great practical importance. Moreover, as the driving fluid entering the engine through conduit 5 has a comparatively low pressure but a large volume, it can be utilized in the turbine 1 with a reasonable peripheric velocity'and size of this turbine, consequently at a moderate number of revolutions,

whereby in many cases gearing between the engine, such as 1 or 7, and the driven machine such as 6, can be avoided.

I have pointed out above that engine 1 or 7 is mechanically independent of stages I,

II and III, but it is also very well ossible to make the several stages I, II, II indendent of one another mutually. .In fact, ust this construction is shown. in the drawwherein the shaft of machines 1, 2 of stage I, shaft of 1",, 2 of stage II and shaft of 1 2 of stage III are without any mechanical connection with one another. Each shaft therefore can be run with the most suitable number of revolutions.

From the diagram, Figure 6, will be seen thatv the net work of expansion of turbine 1 (curve 17 18) is equal to the gross work of compression of compressor 2 (curve 15'-16' it being-easy to arrange the conditions in this manner, wherebythe energy taken by turbine 1 is just consumed by the compression energy absorbed in compressor 2 and by friction resistances, losses of heat, etc. 7 Consequently no work will be delivered out from stage I, and only the energy contained in the outlet gases from turbine 1 will be transported on to the next stage II.

In this stage the conditions are just similar.

to those of stage I, because the net work of expansion of turbine 1 (curve 19'-20') is equal to the gross work of compression of compressor 2 (curve 13'-14'). Finally, in stage III the network of expansion of turbine 1" (curve 20'--21') is equal to the gross work of compression of compressor 2" (curve 11-124 After having left turbine 1 the gases are exerting their useful work (curve 21-22) in the engine 1, 7 etc.,' which consequently is not hitherto loaded with any work of compression.

When all four stages I, II, III, IV are considered as a complete-unit, it will thus be seenthat the output of the different stages before the last one may be so selected that stage in question From the different stages I before the last one no mechanical work is taken out, and the turbines operating in each .of these stages may therefore run with just the number ofrevolutions most convenient to the stage in question. Urfder these circumstances it is preferred: to increase the wheel diameterthrough the stages according as" the gas volumeis increased and to reduce correspondingly the number of revolutions of the turbines of the successive stages. The difierent stages therefore should be provided with separate governors indenendently of each other.

The different stage sections need not be connected to one another in any other manner than through air pipes which connect the compressors in succeeding stages together and through gas pipes which connect the outlet from the turbine of one Stage with the combustion chamber for the turbine of the next stage.

If the useful work ofthe gas turbine aggregate is tobe transmitted through a turbine which may for instance be coupled directly to the driven machine element, this turbine erto ordinary,

proper may possess one or more stages like ordinary steam'turbines. The total fall in pressure between inlet and outlet, however,

will be comparatively small and the theoretical efiiciency consequently correspondingly higher.

As will be understood, it is possible in this manner to obtain a gas turbine unit of a very practical construction without using, as hithhigh ratios of gearing, because the' several stages I, II, III, IV are mechanically independent of each other, and consequently the number of revolutions in any of these stages may be chosen independently of that of the other stages.

The starting of the diiferent stages takes place easily one after the other.

Obviously, the invention is not limited to any specific number of stages. n c

Having thus described my invention what I claim 1s:

1. A gas turbine unit, comprising a series of mechanically independent means for compressing the gas in stages, means for adding ener of heat to the gas after compression, a series of means for expanding the compressed gas in stages down to an appropriate degree, each compressing means being mechanically coupled to one of the expanding means, an engine mechanically independent of said means for compressing and expanding the' gas, and means for conducting the degree, each compressing gas after final expansibnas a drivingfluid to the said independent engine. A

2. A gas tur ine unitcomprising means for gradually compressing the gas in separate stages connectedin series but mechanically independent. of one another, means for adding energy of heat to the gas atsuitable places after compression, means for expandlng the gas gradually to gree in separate stages connected in series but mechanically independent of one anan appropriate deother,means for mechanically coupling togetherthe first compressing means in the Sc ries of compression stages with the last'expanding means in the stages of expansion,

means for mechanically coupling together 2 the second compressing means with the last but one expanding means, and so on, a driving enginemechanically independent of said compressing and expanding means, and means for conducting the so expanded gas as a driving fluid to the said engine.

3. A gas. turbine unit, comprising compressors for gradually compressing the gas through a series of stages, said compressors being mechanically independent of one another, means for adding energy of heat to the gas after compression, turbines for expanding the so compressed gas through a series of stages down to an appropriate degree, said turbines being mechanicallyindependent of one another, means for coupling mechanically together the first compressor in the series of compression stages with the last turbine in the "series of expansion stages, means for coupling mechanically together the second compressor with the last but one turbine, and so on, a driving engine mechanically independent of said compressors and turbines, and means for conducting the so expanded gas as a driving fluid to said engine.

4:. A gas turbine unit, comprising a series of mechanically independent turbo compressors for compressing air in stages, means for ducting the gases after expansion in said ent engine.

5. A' gas turbi e unit, comprising a. series of mechanicallygh iidependent means for compressing air in stages, means for cooling the gas between said stages, means for adding energy of heat to the air by combustion after the last compression, a series of means for ex-'' anding the compressed air and gases of comustion in stages down to an appropriate means being me stages asa driving fluid to the said independmeans, an engine led to one of the expanding mechanically independent of said compressing and expanding means,

chanically coup and means for conducting the gases afterexpansion in said stages as a driving fluid to the said independent engine.

6. A gas turbine unit, comprising a series of mechanically independent means for com:

pressing air in stages, means for cooling the air between said stages, a series of means for expanding the compressed air in stages down to an appropriate degree, each compressing means being mechanically coupled to one of the expanding means, means for adding en ergy of heat to the air by combustion between two of t e expanding stages, an engine mechanica 1y independent of said comressmg and expanding means, and means or conducting the gases after expansion in said stages as a driving fluid to the said independent engine;

In testimony whereof I have signed my name to this specification.

i IBIS WILLIAM AEGIDIUS ELLING.

Images