US1802469A - Combustion turbine - Google Patents

Description

April 28, 1931. F. HoFMANN coMBUsTloN TURBINE Filed Feb. l5, 1927 I' .Eu-F. lll

Patented Apr. 28d, 1931 .UNITED STATES PATENT OFFICE FRIEDRICH HORMANN', OF MULIIEIM-RUHR GERMANY, AssIGNoR To IIOLZWARTH GAs TURBINE Co., OF sAN FRANCISCO, CALIFORNIA, A CORPORATION OE CALIFORNIA CoMBUsTIoN TURBINE Application led February 15, 1927. Serial No. 168,282.

The invention relates to combustion turbines of the explosion type and more particularly to the scavenging systems thereof. In Vsuch turbines the products of combustion remaining in the combustion chambers after the explosions have taken place, must be removed therefrom by scavenging air prior to the admission of new fuel charges into said combustion chambers. This scavenging air, in addition to its other functions, serves also to cool the nozzle valves, the nozzle chambers and the nozzles, and indirectly the blades, of the turbines in question. From the standpoint of economy it is desirable to create the necessary volume of suchscavengdening its limits, Fig. 1 is a diagrammatc sectional view of a combustion chamber with the invention embodied therein Fig. 2 .illustrates a modified form of the invention; Fig. 3 is a further modificationwhich differs from Fig. 2 in the means provided for directing a moistening agentinto the body of scavenging air; Fig .4 shows another embodiment of the invention employing a Venturi tube whereby a m'oistening Huid is sucked up by the. scavenging air as it flows into the charging valve; and Fig. 5 is a section on an enlarged scale hrough the scavenging air valve shown' in ig. 1.v

Referring more particularly toFig. 1 of the drawings 10 represents a-conventional explosion chamber of a combustion turbine,-

which chamber at .one end communicates with the nozzle chamber 11 terminating in a nozzle 12 located in operative proXimi-ty tothe blades 13 of the rotor 14 customarily forming part of such combustion turbines.

Ing air with'the least expense of power, while technicallyit is most desirable to increase to The communication between the combustion chamber-10 and the nozzle chamber 11 is controlled by means of-a nozzle valve 15 operated in any usual and conventional manner.

At its opposite end the combustion chamber 10 is provided with an inlet valve 16 for controlling the admission ,of scavenging air into the explosion chamber whereby the latter is scavenged and the products of combustion remaining after an explosion has taken place, are expelled therefrom. The valve 16 is connected by means of a pipe 17 with a source of air under pressure. The valve 16 shown in Figs. l and 5 may be hydraulically controlled and to this end the stem b of the valve may be provided with a piston c slidable within a cylinderd forming an extension of the valve casing a. A spring e is arranged to urge the valve against its seat 31. A conduit f is adapted to be connected alternately to a source of Oil under pressure and to an eX- haust space for such oil, so that the valve is opened at predetermined instants by the oil under pressure and closed by the spring upon exhaust of such oil. As so fardescribed the turbine may be of any usual form and arrangements, the illustration in Fig. lbeing diagrammatic in character; generally speaking, turbines of the class in question include also inlet valves, such as valve 16; for the combustion air and for the fuel, which valves are located at the same end of the combustion cham-bei` 10 as the valve 16. As these valves form no part of the present invention they have not been shown in detail; the construction and operation of such valves are disclosed, for instance, in the patent to Holz- 'Warth No. 877,194. In the form of the invention shown in Figs. l and 5 the seat 31 of the valves 16 i-s lin the form of a flanged ring set Into the valve casing a and provided with apertures 20 (shown more clearly in Fig. 5) which are inclinedl with respect to the axis of the valve-16 and' converge inwardly/towards saidaXis. The arrangement is such that'in its closed position the valve 16 covers and thereby closes the exit ends of said apertures 20. The latter at their inlet ends communicate with an annular channel22 formed in the valve casing a and connected by means i become mixed with the scavengin valve 16 is opened to admit a current of scavi of a passage 23 with a pipe` 21 which leads to a'source of supply of moistening iuid,.such as water or steam. o

.In the operation of the turbine, after an explosion of the fuel mixture has taken place in the combustion chamber ,10, the inlet enging air into said chamber which not only scavenges the latter byexpelling therefrom the products of combustion remaining in the chamber 10 subsequent to said explosion, but also serves to exert a cooling action on the' nozzle valve 15, the nozzle chamber 11, and indirectly the blades 13 of the rotor 14. As the valve 16-is opened to admit scavengingv air into the combustion chamber 10, the exit endsof the apertures 20 will be uncovered and thereby will at the same time admit a supply of moistening fluid into the combustion chamber. This fluid enters said chamber in the form of jets or sprays which converge toward each other from said apertures 20 and air. In this way a-supply of moistening uid is introduced into the combustion chamber 10 into the presence of the scavenging air .therein and becomes mixed with the supply of scavenging air in saidchamber 10, In other words, the scavenging air eithercoincidentally with its entrance into the chamber 10 entrains moistening fluid. or approximately at the same timel is moistened within said chamber.

In the form shown in Fig.4 2, the air inlet va1ve .16a controls the communication between the interior of the casing a and the entrance end of the combustion chamber 10, the

casing a'being connected by means of a pipe 17a with a source of scavenging air. The

valve 16a is carried by' a valve stem 6 upon which a piston c is mounted; the latter is `slidable in a cylinder d projecting'axially fromthe chamber a, said piston c being acted upon by a spring e to maintain thavalve 16a in its \closed position and to return it thereto. The cylinder d is connected by means of a pipe f with a. source of hydraulically orotherwise developed pressure arranged to become eii'ective upon the valve piston c at the proper time to shift it to the right in Fig. 2l and to thereby adjust the valve 16a to its open position. The piston c carries an auxiliary piston 27 a which slidably extends into an' auxil-` 'iai'y cylinder -28a` connected by means of a pipe 21a with a source of moistening fluid either liquid or gaseous. A'tube 19a extends lengthwise of the cylinder-d and hasl its inlet end in connection with the auxiliary cylinder 28a and controlled by the auxiliary piston 27a. At' its opposite end the tube 19a terminatesin a nozzle 20a projecting in an vupward'direction at an inclinationtoward ythe valve 'seat against which thev valve 16d closes. -l l j In the operation of the turbine-provided' Cindicated by dotted linesv in Fig. 2;- This operation of the valve 16@ occurs subsequent- 1y to the explosion of a fuel charge in the combustion chamber 10 and serves to' admit a supply of scavenging air to the latter whereby the products of combustion, remaining in said chamber, are expelled therefrom. As j this adjustment of the valve 16-to its open position takes place the auxiliary piston 27a is caused to describe acorrespondlng movement to the right in-Fig. 2 which is sufficient in extent to uncover the inlet end o the tube 19a and to thereby bring said tube into open communication with the pipe 21a and consequently with the source of'moistening fluid.

As `this occurs the moistening fluid will be expelled from the nozzle 20a and will be ejected therefrom in the-form of a jet or spray which passes by the-open valve 16a into the combustion chamber 10 and becomes mixed with the scavenging air therein.

In theV form shown in Fig. 3, a tube 196 c'orresponding to the tube 19a of Fig. 2 instead of .terminating in a nozzle such as 20a, communicates with an annular channel 206 lo-v catedl in close proximity to the seat against which the air inlet valve 166 seats itself in its closed position. The annular channel 206 is provided with apertures g which project radially inward and establish communication between the channel 206 and the casing a which corresponds to the casing a of Fig. 2. Otherwise the form shown in'Fig. 3 may be constructed and operate in the same Wag as the form shown in Fig. 2.

fter the valve 166 is opened the inlet end of the tube 196 will be uncovered as in Fig. 2 and moistening fluid will accordingly pass through the apertures gfin the form of jets or sprays and into the current or scavenging airiowing from the casing a" past the open valve 166 into the combustion chamber 10. The apertures g and accordingly the jets of moistening fluid passing inwardly therethrough are located at the point at which- Athe speed of inflowin current of scavenging to the previously mentioned casings a an a and atits other endis connected bymeans of a pipe 17 6with `a source of scavenging air ing air in .flowing through the under pressure. An injector nozzle 20c extends into the Venturi tube 31 and is connected by means lof a passage 190 with a collecting vat 2lb arranged to contain a supply of clear water or other suitable moisteiiing fluid L and connected by means of a pipe,J V21e with a source of supply of such meistening fluid. A float valve carried bya float j serves to automatically control the commu-v nication between the pipe' 21e and the interior of the vat 21Zi`whereby a supply of fluid z, is continuously maintained in said vat. A valve 7c is manually operated, for instance by means of a handle l, to. control the connection between the chamber and the nozzle 200.

A s the air valve 160 in th-is form of the invention is opened to admit a supply of scavenging. air to lthe combustion chamber l0 as in the forms previously described, the scavenging air will flow from'the pipe 176s through the Venturi tube 31 and'cl'iamber a2 into the chamberlO. The current of scaveng- Venturi tube 31 will develop a suction or ejector action in the nozzle 205 and thereby serve to draw the moistening fluid 71. through said nozzle in the form of a spray or jet. In other words, as the scavenging air passes the nozzle 20c it entrains moistening fluid 7i issuing from said nozzle.

In all of the arrangements the humiditying or moisten-ing 'of 'the scavenging air, either with clear water, withvaporized water in the form of steam, or with any other suitable `inoistening agent, takes place either coincidentally with the introduction of the scavenging air. into the combustion chamber or at approximately the same time. The moisture entrained in theaforesaid scavenging air causes the development of steam owing to the high temperature of the walls of the explosion chamber. As in a mixture of gases the pressure of the mixture is equal to the sum of the partial or individual pressures of its constituents, the partial pressure of the air is decreased by the development and admixture of steam, the total pressure remaining unaffected, whereby an increase in the volume of the air is caused, se that a smaller quantity of scavenging air need be employed. The mixture of air and moistening fluid and more particularly the mixture of air and steam develops a much higher and more efficient cooling action than air alone. The moistening fluid instead of being added to the air in the form ofpreviously created steam or vapor, may' also, in part, comprise cominuted or atomized water which first becomes vaporized as it escapes into the combustion chamber on its -way through the chamber and through the associated elements. The addition of water can therefore take place in liquid form or in the form of vapor and may 'occur during the entire period of entrance of. air into the chamber 10 valve lsaid valve for introducing a or during a part of said period. It may begin for instance after the entrance of the latter into the said chamber. Other timing arrangements may be adopted without departing from the nature of my invention as set forth in the claims. By adding the moistening fluid to the scavenging air the formation of scalein the combustion chamber on the associated elements is reduced and practically done away With. If clean Wateris not available fit is desirable to previously remove the scale either wholly or in part. This may be done by using cleared hot water in the turbine, as with a temperature of over 60 the scale for the most part will easily fall away. When steam is employed it is of advantage to use the exhaust steam of the turbine. f

Various changes in the specific forms shown and described may be made within the scope of the claims from the spirit of my invention.

I claim:

" '1. In a combustion turbine of the explotion and expansion of the explosive charge,

scavenging air into said chamber for scavenging the same, and mea-iis whereby a liquid without departing i moistening fluid, in the form` of jets, is introduced into the body of said air for admix` ture therewith.

2. In a combustion turbine of the explo-4.

sion type, the combination chamber, an air conduit for introducing scavenging air into said chamber, an air controlling the admission of. said scavof an explosion enging air to said chamber, erating coincidentally with the opening of moistening liquid agent into the body of said air for admixture therewith. y

' 3. In a combustion turbine of the explosion type, the combination of an explosion chamber, an air conduit for introducing scavenging air into said chamber, a valve casing connected with a source of moistening fluid, an annular member in said casing constituting a valve seat and provided with inwardly converging apertures, an annular channel in said casing connected with said apertures and communicating with said source of moistening fluid, an air valve cooperating with said seat to control the admission of said scavenging air to said chamber and also controlling said apertures for the coincidental admission of moistening fluid into the body of said scavenging air.

, 4. The improvement in the art of generating power with the aid of explosion gases obtained by the successive explosions of combustible 4mixtures of fuel and air intermittently charged into a confined explosion space, which comprises charging air into and means opsuch space, after the explosion of a charge therein and the expansion of the resulting combustion gases, to scavenge said space of the residual hot explosion gases, and substantially simultaneously charging moistureinto such space andthereby converting such moisture into steam, whereby the quantity ofair necessary to scavenge such space 1s reduced and a greater cooling effect is obtained. In testimony whereof I have hereunto set` my hand. i

FRIEDRICH HOFMANN.

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