US1580878A - Combustion turbine - Google Patents

Description

' April 13., 1926.

L. DUFOUR COMBUSTION TURBINE Filed May 24, 1922 3 "Sheec s-Sheet 2 April 13 L. DUFOUR COMBUSTION TURBINE.

Filed May 2 4, 1922 3 Sheets-Sheet 5 combustion and for operating the turbine s-ta Apr. 13,1926.

' UNITED STATES- JZEON nuro'on, or emmv'a, swrrznnna'nn:

eomaus'rxon TURBINE.

Application filed Kay 24, 1922; Serial no.,.5oa,2o0; '1

To all whom it may concern:

Be it known that I, Lr'zon DUFoUR, a cltlzen of Switzerland, residing at Geneva,

Canton of Geneva, in the Confederationof Switzerland, have-invented certain new and useful Improvements in Combustion Turbines, of which the following is a specificatiom Under the'general term combustion turbine there is herein to be understood any machine which generates motive force in which the expansion of gases produced by the combustion of any fuel such as gas, oil, tar, petroleum, petrol, coal and explosives, etc., is utilized by a turbine. It is known that combustion turbines called also gas turbines may be divided into two 'main classes, i. e., turbines at'constant pressure and explosion turbines. This invention applies to both of theseclasses of combustion turbines.

The invention herein claimed relates to an apparatus in which the cooling of the wheels and of the blades of the wheels of acombustion turbine allows'a turbine to be constructed which possesses excellent conditions of efficiency and an arrangement for. carrying out such process in a combustion turbine.

. The apparatus consists, in aj-combustion' turbine, in which the wheels and especially their blades are cooled by passing cold air and if desired'thc cold gases necessary for into such wheels and blades, and also if desired the burnt gases after they have performed their work in the turbine and after they have been suitably cooled, while utilizing the passage of the air and it may be gases in the wheels of the turbine at the sametimeto increase the pressure of such air and gases. The apparatus also consists of a. turbine having a plurality of pressure stages, and one or more speed stages per pressure stage.

the turbine having'a plurality of wheels in which wheels and their blades are so constructed as to serve both as turbine wheels and compressorfwheels, and in which the wheels and their blades successively receive burning active gases coming from'the combustion or explosion chamber or chambers,

gases whose speed and it may be-pressure 1s utilized by the wheels and the cold air or gases compressed by such wheels. In'such turbines the blades of the same wheel are therefore successively employed to transform the pressure and speedor speed oInly of the active hot gasesinto rotary movement of the wheel, then to transform the rotary movement of the wheel into speed and into pressure of the air or cold gases to be compressed. The heat communicated to the blades and to the wheel by the hotactive gases will be transmitted as produced by the wheel and the blades to the air'or to the cold gases so that-the wheel and the blades will be maintained at a temperature intermediate between the temperature of the hot active gases and that of the air' or cold gases. 1

. Finally such arrangementcomprises sev-' e 'al parts or machine elements which will herein be successively described and whose application to the new arrangement for a new object alto constitutes novelty. p

The invention is illustrated by way-of example in which' Fig. 1 is a diagrammatic longitudinalsection of a combustiomturbine for carrying out the process.

Fig. 2 is a transversb section taken on the line 22 of Fig. 1.

the accompanying drawings of" Figs. 3 and 4 show two arrangements of a wheel for such turbine.

Figs. 5, 6, 7, 8-, 9, :10 and 11 show details of the-constructiono-f the blades of such Wheel and the method of securing them.

Finally Figs. 12-, 13' and 14 show three views of a Wheel provided with different.

arrangements of blades.

The turbine illustrated by way of example in Figs. 1 and 2 is a combustion turbine burning liquid fuel, crude oil-for example, of the axial type having five pressure stages, each pressure stage having one speed stage only, three-of such stages working above atl mospheric pressureand the other two stages workingb elow atmospheric prezsure. The" turbine is divided into two sections of which the upper section as illustratedcomprises nearly three quarters of the circumference 'where the wheels work as rotary compressor wheels, and the lower section where the wheels work as turbine wheels properly so ca led.

In Fig. 1, a {is the turbine shaft, 6 b b 11 and 'Zr" are the five turbine Wheels keyed on shaft a. Each wheel consists of the portion 1) which comprises the hub keyed upon the shaft and flange -0 connected to ortion b by ribs d forming portions ofthe blades. A circular'channel ,e, e is thus hill formed in each wheel between portions 7) and a'. The blades f are fixed at the circumference of each wheel between portion 6 and flange c. The blades are, outwardly to the wheel, of the general shape of theprovided with blades fixed at their external radial portion. Blades f of the wheel pass with very little play into the internal radial portion of these channels. The diffusing channels communicate with other channels b 7& b which connect channels g g and g with the inlet of the wheel following, and channelsg and g with the channels k and 12. leading to the outlet pipe for the gases or air. 2' is the inlet tube for the burnt gases into the compressor and i the outlet tube for the same burnt gases into the atmosphere. 2' is the inlet tube forthe air required for combustion and i theout let tubefor such air after its passage into the compressor section.

In the lower portion of Fig; 1 in which the turbine acts as a turbine properly so called, k k are channels leading gases pass ing out of the blades of one wheel to the guide blades of the following stage, m m are the guide blades of each stage. the inlet tube for hot gases passing into the turbine and passing out of the combustion or. explosion chamber, which isnot shown in the drawing. 0 is an outlet tube for said gases passing out of the turbine after hav ing traversed the blades of the five wheels. 37 p are diaphragms separating the different pressure stages of the turbine from each other. 12 p are portions of said diaphragmswhich being situated 'very near to the inlet into channels 6 of wheels I), serve to close the inlet to such channels when they pass into the section of the turbine properly so called. Behind each closing portion 12 is a channel u which allows the internal radial portion 9 of the channel or channels immediately preceding the turbine section to communicate with the internal radial portion of the channel or channels immediately following the turbine section. I I

Lastly s s is the outer wall creasing of the mach-inc.

Fig. 2 is a transverse section of the 'same turbine taken on the line 22 of Fig. 1, said line. deviating from the straight according as the section relates to the compressor portion or to the turbine properly so called. In Fig. 2, a is the turbine shaft, h 72. chaneeds-2s nels which leads air into the inner part of the compressor, and g the circular s ace forming a continuation of: the prece ing diffuser and which allows such diffuser to communicate with channels 72.. i is the inlet tube for air into the compressor section. In the lower or turbine section 12 is the diaphragm separating one pressure stage from the other pressure stage of the turbme. p is the portion of such diaphragm which closes the inlet of the channels of the wheel. k is the channel leading the gases passing out of the blades of the preceding wheel to the directing blades m. .r r are walls sepa rating the turbine section from the c0mpressor section, r is an enlargement of wall 1' placed at the spot where the wheel passes from the compressor section to the turbine section and serving as the wall p to close the inlet of the channels of the wheel, such channels being marked 0 in Fig. 1. As seen in the figure such closing surface 9 p? is set at an angle with respect to tlie turbine section and behind said portion 1' p is channel it shown dotted, but which can well be seen in Fig. 1; this channel allows the internal radial portion .of channels it preceding the turbine section to communicate with theend portion u. of channel a as shown in Fig. 2. s s is the outer wall or casing of the machine.

In Fig. 3 which shows one method of constructing a wheel I) is the Wheel hub forged in a single piece with the main disk 7).

cl (1 are ribs forged together with the disk and hub or formed by cutting away metal. Ribs cl are sharpened at d and at (P so that when once the wheel is mounted such ribs form blade elements. ondary disk of which the enlarged portion a is in mounting fixed upon the correspond ing rounded portion of ribs d. In Fig. 3 flange 0 is shown separate from main disk I), and therefore before being mounted upon the disk. The'lesser diameter 25 of enlarged portion 0 is a little smaller than diameter 25 above the commencement offthe ribs so that the flange 0 should be mounted while hot when the temperature of the flange is sufficiently high for diameter t ,to be a little larger than diameter 2, of the ribs. After cooling flange 0 is then firmly applied on ribs (1 and flange 0 will be in some measure in one with main disk I). The disk and flange maintained at the required distance by ribs d will form between them a circular channel having walls converging towards the outer circumference provided the fian e.

seen in section is inclined. w o and o 2-0 are circular dovetail grooves formed on the internal facesof disk 7) and of flange c, said grooves serving to fix the blades.

In Fig. 4-. which shows another method of making the wheel the same letters designate the same parts as in Fig. 3. In this other the disk may also be combined together inand flange c.

arrangement enlarged portion of the flange is provided at m with an internal screw thread and screws on to'ribs d which are at y provided with an external screw thread. These two ways of mounting the flange upon this sense that the flange may be screwed while hot upon the ribs on the disk.

Fig. 5 is a front elevation of one of the blades fixed on the wheel between the main disk and the flange. f shows such blade which is formed of a sheet of metal suitably curved or forged to-the shape of a gutter just as in a normal steam turbine blade. The blade however in this case remains open at the internal radial end as also at the external radial end because it must serve both as turbine blade and as compressor blade. Lugs z z formed in one with the blade serve to secure it by engaging grooves to 02 in disk .6 Such lugs may be dovetail as are the grooves indicated in the figure V 7 but this'is not a necessity. The figure shows responding dovetails.

two lugs and two grooves, one on eachside,

; but the number of lugs on each blade and their corresponding grooves. may be greater.

Fig. 6 is a profile view of the same blade, taken on the line 6 6 of Fig. 5.

Fig. 7 is a plan of the same blade and neighbouring blades takenon the line 7-7 of Fig. 5. In Fig. 7 a 2 are distance plates also seen'in section which are interposed between each blade and which are maintained in grooves 'w 'w It is'mainly to fix these plates that. grooves w *w are made dovetail:

and of course plates 2 are provided with cor- The plates are inserted into the grooveby means of a notch indicated by dotted lines 9 in Fig, 5, such notch being then filled up in any suitable manner. If the blades in place of being radial as indicated in Fig. 5 are inclined with respect to the radius of the wheel as shown in Figs. 13 'and14 the distance plateswhich are inclined also may'in certain cases be'mserted 1nto the groove in a very slmple manner; to insert them 1t 1s only necessary to incline them still more and then tostraighten them. The last plate of a tier is inserted after it has been curved sulficiently to allow it to enterthe groove, it is then flattened. when .position. These plates maintain" the distance between the blades and cooperate in maintaining the blades rigidly fixed.

Fig. 8 shows in front elevation, side elevation and plan 'twoqdifierent types of such plates. The left. hand plate is intended to separate radial blades such as those indi- 'cated in Fig. 12 and that on the right hand to separate inclined blades such as those in dicated in Figs. 13 and 14.

Fig. 9 shows a blade similar to that shown in Fig. 5; in Fig. 9 however the inclination of flange c seen in section continues as far as'the outer circumference of said flange so that the circular channel formed between flange c and main disk 6 is converging up to its end and so that the portion of the blade engaging such channel is trapezoidal as is clearly shown in Fig. 9. In Fig.5 the inclination of flange a ceases at the base of blade f so that the walls of the channel between the flange and the main disk become parallel near to the blade andso the portion of'the blade engaging in such channel is rectangular. In Fig. 1 the difi'errntgvheelsare constructed according to both these methods.

Fig. 10 shows one ofthe long blades, 7':

with its two sets of lugs 2 2 and a 2 which are lodged in grooves w 'w and v '0 on the wheel. Each wheel comprises a certain number of short blades and acertain number of long blades which may of course be provided .with more than twopairs of lugs. A same from the blade, are relatively very large measuring more than 40.

Fig. 12 shows a wheel with its blades in position seen in front elevation. I11- this arrangement the blades are mounted radially and there is always one long blade f for two short blades f. The circular grooves 'w 4) which serve to maintain the blades in position are indicated by dotted lines.

Fig. 13 shows another arrangement of wheel in which the blades are no longer mounted radially but are inclined rearwardly with respect to the direction of. rotation of the wheel, and such inclination can easily be obtained by interposing between the blades in the grooves 'w 0 distance plates having an inclined shape such as indicated on the right hand side of Fig. 8. In this figure the wheel shown always has one long blade f for every three short blades 7.

--F1nally Fig. 14 shows 'a third arrangement of wheel also having inclined blades I but having for each long blade f four short blades f and one medium size blade f intermediate between and interposed symmetrically between the short blades.

In this arrangement there is formed in the disk and in the flange a third pair of circular grooves 'w intermediate in size between grooves w and a); such grooves are particularly useful-for fixing the base of medium size blades f while they also support themiddle "portion of long blades f. The numberof types of blades of diiferent lengths may of course be increased and they of Fig. 1.

may be arranged in no matter what order with a view to obtaining a compressor wheel of advantageous shape.

The working of the turbine shown diagrammatically and by way of illustration in Figs. 1 and 2 can easily be understood; the air necessary for combustion is sucked from the atmosphere through tube i and is compressed to the required pressure by the three wheels 6 b 6 shown on the left hand side These wheels at the u per section of the machine behave exacty as the wheels of an ordinary rotary compressor. Air is first compressed inside each wheel by reason of the difference between the relative speeds of inlet and outlet and by centrifugal force. The absolute outlet speed of air from the wheel is then transformed into the blades of first wheel 6 in the lower sec-- tion of the machine which is the turbine section. The said first wheel from the turbine point of view is at the same time the last-wheel from the compressor point of view. In passing out from the blades f of this wheel the gases are directed by channel is into'guide blades m of the second stage ofthe turbine and so on until the last stage and to last wheel 6 In each series of guide blades the gases expand to a lower pressure and therefore increase in speed which is then utilized by the corresponding wheel. In passing out of last wheel I) the gases have fallen to a pressure lower than atmospheric pressure and they must be compressed in order that they can escape into the at-' mosphere.-

At the moment whentthe blades ot a wheel 7 11 r is the inlet into-channels e of thev wheels and p T have for their object the e oft e wheels when the closing of suchinlet channels and thus "pre- .ventin air or'gases enterin into channels lades of such wheels are passing th'rou h the turbine sec tion. Itis even'preferab e that the closing of the channels'e should commence a mofrom the compressor section-into the turbine section in order that the air or the gases in the channels e at the moment of closing still have time topass through the wheel as far as the blades and.can still escape into the compressor section. In the same manner it is preferable that closing of the inlet of channels 0 should cease before the blades have left the turbine section so that the air or the gases may have time again to enter the wheel and to traverse it radially and to pass radially between the blades when these reenter the compressor section. This is the [reason why closing portions 17 r in Fig. 2 isset at an angle in advance of the direction of rotation of this wheel with respect to the turbine section. In rear of the closing surface a channel u places the internal radial portion of the channel it immediately preceding the turbine section into communication with the internal radial portion of the channel It immediately following such turbine section so that continuous circulation of the.air or gases in the compressor may not be interrupted e cept for the interruption necessary in the interior of the wheel as has above been explained.

The method of constructing the wheels and blades and the methodof fixing the blades in the wheels will easily be under-' stood from the description of Figs. 3 to 11. In order to improve the working of the compressorthe blades may be inclined rearwar'ds with respect to the direction of movement ofthe wheel as has'been indicated in Figs. 13 and 14. In this case the guide blades of the turbine may be given an inclination suitable to this inclination of the blades of the motive wheels. In each wheel blades of different. lengths may be alternated as is indicated in Fig. 12 to 14, in brief,-inside such wheels the blades may have the shape and be arranged as is most suitable from the compressor point of view. The advantages of the process and the method of carrying it out are evident by mere inspection of Figs. (1 and 2. The cold gases or air passing into the compressor commence at once to cool the blades which in the turbine section are in contact with f the 'burning gases. The blades and the wheels'will thus at each stage of, the machine have a temperature intermediate between that of the burning gases and that of the cold air. or gases. Knowing the value of the coefiicient of transference 'of heat between the g'asesor the air and the blades for ent temperatures of the blades, the necessary speeds and cross sections may easily be found for the burning gases on the one hand and for the cold gases or air on the other hand in order so to arrange that the 0 ment before the corresponding blades pass bladesfdo not exceed a limited predetermined iao temperature. It ma be noted that cooling is facilitated by the diet that the cold gases or air pass radially between blades which have a relatively large radial height while the burning gases traverse blades axially and a portion only of their radial height. The heat transmitted by the burning gases to the blades may partially be distributed over their whole radial height and will thus more easily be dissipated by the cold gases and air. For example, in the first wheel of the, turbine the gases may be allowed to enterat atemperature of 900 or 1000 C. or more and the arrangement however be such that the blades do not exceed a maximum temperature of 400 C.

From then on turbines having a pluralit of pressure stages may as shown bythe above described example, be employed as combustion turbines, for example, turbines having to pressure stages or more, that is to say the turbines will possess efficiencies much greater than turbines having a single pressure stage as has heretofore been proposed for combustion turbines.

It will be of advantage in each wheel that the pressure in the compressor section should approximately be the same as the pressure in the turbine section as the passage of aim or gases from one section to the other, where the wheel passes from one to the other, would thus be avoided and so loss of air or gases. It is known however in rotary compressors that when the tangential speed of the wheels does not exceed 150 to 200 metres per second that the increase of pressure obtainedfrom each stage of wheel and diffuser is relatively small and is less thanthe fall of pressurewhichcan be utilized in a correponding combustion turbine stage with the same tangential speed of the wheel.

A method of obviating the difiiculty of obtaining substantially the same pressure in a compressor section stage as in the corresponding stage of the turbine section will be to lessen that portion of the speed of the burning gases utilized by each turbine wheel in the turbine section by increasing above the usual limits the angle of inclination of the guide blades upon the plane of the wheel. In normal steam turbines this angle varies, between and An angle of at least may here be taken. The inlet angle of the wheel blades will then have a'value of at least 40, a value much'greater than the usual value. The proportion of the speed of the gases then utilized by the wheel and transformed by it into work will be less great than if the angles were normally small while the absolute speed of outlet of the gases from the blades will be greater; such absolute outlet speed is moreover utilized to a large extent by the crown of guide blades at the stage following. This means that the fall of pressure utilized by one stage of the turbine section will be smaller than in a turbine having normal angles for the guide blades and the blades of the wheel and thus it will be easier-to make this small fall of pressure correspond to the increase in the pressure of the air or of the gases in the corresponding stage of the compressor secthe blade'will be less curved the blade will be better suited to act as compressor blade for it is to be noted that in the compressor section it is the convex surface or the back of the blades which is-the surface directly acting upon the air or gases to be compressed.

The apparatus herein shown and described is illustrative of one manner in which my invention may be carried out, and it is to be understood that the same may be varied within the scope of the claims without departing from the nature and spirit of the invention. 0 a

Having now particularly described and ascertained the nature of my invention and in what manner the same is to be performed, I declare that What I claim is 1. In an apparatus of the class described,

a casing, a plurality of rotors each having a mo passage therethrough, a plurality of blades carriedby the said rotors, means for admitting air into the casing and to the said passages in the rotors during a part of each revolution thereof, for utilizing said blades as compressor blades, means for closing the entrance to the passage in each rotor during the remainder of each revolution thereof, means for'directing combustion gases to the said bladesduring the said remainder of each revolution thereof, and thereby utilizing the said blades as turbine blades during this portion of the revolution, and inlet and outlet connections for the said combustion gases.

2. In an apparatus of theclass described, a casing, a pluralityof rotors mounted in the casing, and each having a passage there through, arplurality of blades mounted in, and extending from the said rotors, means for admitting air into the casing and to the said passages in the rotors during part of.

said blades as turbine blades ,'-and inlet and outlet connections for the said combustion gases.

3. In an apparatus of the class described, a casing, a plurality of rotors mounted in the casing, webs in the rotors providing ineach thereof a plurality of passages, a plu'- tion gases.

ing the said blades as turbine blades, and

inlet and outlet connections forthe combus- 4. In an apparatus of the class described, a casing, a plurality of wheels revolubly mounted therein, eachwheel comprising a primary disk, and a secondary disk spaced therefrom and secured thereto to provide a 'pas'sage'therethrough, a plurality of blades mounted in each wheel, .meansfor admitting air into the casing and to the entrance to the passages in the wheels during a part of each revolution thereof, for utilizing the said blades as compressor blades, means for closing the entrance to the said passages in the said wheels. during the remainder of each revolution thereof, means for directing combustion gases to the said blades during the said remainder of each revolution of thesaid wheels, for then utilizing the said blades as turbine blades, and inlet and outlet connections for the combustion gases.

5. In an apparatus of the class described, a casing, a plurality of wheels revolubly mounted therein, each Wheel comprising a primary disk, a secondary disk spaced therefrom and secured thereto, and webs between the said disks providing passages therethrough, a plurality of blades secured in 4 each of the said'wheels between the disks m'ainder of each revolution thereof, to then ut lize thesaid blades as turbine blades, and;

.t-here'of; means for admittingair through the casing and to the passages in each wheel during a part of each revolution thereof, for then utilizing the said blades as compressor blades, means for closing the. entrance to the said passages through thesaidjwheels during the remainder of each revolution thereof, means for dlrectlng combustion gases to the said blades during the said-re,

inlet and outldt connections for the said combustion gases. 6. In an'apparatus of the class described, a casing, a plurality of wheels revolubly mounted therein, each wheel comprising a primary disk, a secondary disk spaced therefrom and secured thereto, and webs providing passages extending therethrough, a plurality of blades mounted between the disks of each wheel, and extending therebeyond, means for admitting air through the casing and to the passages through the said wheels during a part of each revolution thereof, to then utilize the said blades as compressor blades, partition walls in the casing closing the entrance to the said passages in the wheels during. the remainder of each revolution thereof, means for directing combustion gases to the said'blades during the said remainder of each revolution of the said wheels, for then utilizing the said blades as turbineblades, and inlet and outlet connections for the said combustion gases.

7. In an apparatus of the class described, a. casing, a plurality of spaced wheels revolubly mounted therein, each wheel comprising.a primary disk, a'secondary disk spaced therefrom and secured thereto, and webs between the saiddisks forming a plurality of passages between'the same, the entrance to the said passages in each wheel being substantially axial, and the discharge from the said passages being substantially radial, there being passages in the casing between the discharge from one wheel and the entrance to thepassagesto the next succeeding wheel, a plurality of blades mounted between the disks of each wheel, and extending therefrom, means for admitting-air'into the casing and to the entrance to the said pas sages in the said wheels during a portion of each revolution thereof, to then utilize the said blades as compressor ,blades, partition wallsin the casing for closing the entrance to the passages in the wheels during the re-' mainder of each revolution thereof, and a serlesof director Dlatesfor directing combustion gases to the blades of each wheel during the said remainder of each revolution thereof, for then utilizing the said blades as turbine blades, there being a passage in the "casingbetween eachof the said wheels for the said combustion gases, and inlet and out let connections for the said combustion gases. I

' LEON. D FOURL

Images