US2207762A - Process for operating combustion turbines and apparatus therefor - Google Patents

Description

sheets-snee: 1

Ww* @w ATTORNEYS July 16, 1940. w. 'SCHMIDT PROCESS FOR OPERATING COMBSTION TURBINES AND APPARATUS THEREFOR Filed sept. 50, 195e July 16, 1940. w. SCHMIDT 2,207,762

PROCESS FOR OPERATING COMBUSTION TURBINES AND APPARATUS THEREFOR Filed sept. so. 195e `2 Smets-snee: 2

INVENToR WILHELM .scf/M407' 4Arromuavrs Patented July 1s, 1940 UNITED STATES PATENT oPFlcE PaocEss Foa OPERATING coMBUsTroN mamas AND APPARATUS 'rnEaEFoa wilhelm schmidt, oberhausen, Germany, as-

signor to Holzwarth Gas Turbine Co., San Francisco, Calif., a corporation of Delaware Application september so, 193s, sel-iai No. 232,495 In Germany October 10, 1937 effecting the discharge of the explosion gases from constant volume explosion chambers to places of use in suchmanner that losses are reduced or eliminated and more efficient utilization of the energy of the gases obtained.

More particularly, my invention relates to an improved process for regulating and controlling the discharge of explosion gases from the explosion chamber' or chambers to different places of use in accordance with the pressure head of the successive portions ofthe gases discharging from the chamber during each cycle, and in such a manner that the gases are more efiiciently utilized in engines or other apparatus best suited for operation with gases at the. particular ranges of pressure of the diiferent portions of gas.

Stated briefly, my invention comprises the regthe explosion chamber at their lower pressure range, and especially of the residual gases expelled from the explosion chamber by the incorning air during the scavenging .or combined scavenging and air charging period, in such a manner that the pressure in theconduitleading such rel- I atively low pressure gases to their place of utilization (which is more removed from the discharge end of the explosion chamber than the place of use for the higher pressure gases) is maintained continuously higher than that prevailing at the 40 use in combustion turbines, it has-been found desirable to discharge only the ilrst part of the combustion gases, that is, the portion at the higher pressure head, out of the explosion chamber through the usual outlet member. The other part of the combustion gases, which after the discharge of the first part remains behind in the explosion chamber with greatly reduced pressure, is not ordinarily suitable by reason of its reduced pressure for use at the same place of utilization. 53 lThis is particularly true for that part of the combustion gases which remains behind in the explosion chamber after the expansion is completed and must be expelled from the explosion chamber by the fresh charge, for example, by the newly admitted combustion air.` This second part of the --J ulation and control of the vdischarge of gases'from combustion gases has, therefore, 'been discharged out of the explosion chamber through a separate discharge member arranged at the discharge end of the chamber, similarly to the main discharge member or nozzle valve. This second gas portion is thenled to a separate place of use 'which is `particularly adaptedfor the utilization of these gases of lower pressure. As the second place of use cannot in general be arranged in the immediate vicinity of the above mentioned separate outlet member for the second part of the combustion gases, and as the arrangement of the outlet member itself is clearly determined by the position of the explosion chamber, there result comparatively long connecting conduits between the separate outlet member and the additional place of use. From this it follows that the total interior space of the comparatively long conduits so created must be repeatedly lled, at each opening vof the separate outlet member, that, in every cycle, with thecombustion gases which `are still under considerable superatmospheric pressure. The pressure in these connecting conduits of known constructions falls to the pressure prevailing at the place of use after closure of the separate outlet member, and thus usually to atmospheric pressure, whereas the second part of the combustion gases at the moment of discharging from the explosion chamber still possesses a comparatively high pressure, which can amount to Il) atmospheres and above. Consequently, the repeated iilling of the extended connecting conduits with the `still comparatively highV pressure and hot combustion gases not only leads to output losses corresponding to the pressure drop, but these losses become particularly high also by reason of the fact that during the filling of the 'conduits strong whirlings arise with correspondingly high whirling velocities resultingin' surprisingly high output losses because of the intensive heat withdrawal associated therewith.

According to the present invention, the discharge of the gases from the explosion chamber or chambers, and particularly the gases of lower pressure range, the gases being led to different places of use during each working cycle divided according to pressure, quantity, or pressure and quantity, is so conducted and controlled that the conduit or conduits leading the lower pressure gases to their place of use are maintained continually under higher pressures than those prevailing at the place of use.

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panying drawings forming part of this specication, wherein Fig. 1 represents a schematic longitudinal section through an explosion turbine plant, in which separate or auxiliary valves are provided both in the immediate vicinity of the explosion chamber as well as immediatelyin advance of the place of use;

Fig. 2 illustrates a side view of a combustion turbine plant in which each explosion chamber is provided with only one special valve arranged immediately in advance of the place of use, there being no auxiliary exhaust valve atthe discharge end of the chamber; and l Fig. 3 corresponds to a vertical transverse section through the combustion turbine according to Fig. 2 along the line III-III of the latter.

The present invention can be embodied both in arrangements which vhave an auxiliary outlet valve at the discharge end of the chamber for thelower pressure gases and also in those which do not. Thus explosion chamber arrangements which have, in addition to a valve discharging the higher pressure combustion gases, a separate valve for the lower pressure gas residue to be expanded out of the explosion chamber after the partial evacuation by the higher pressure com` bustion gases, are advantageously characterized by the feature that the separate valve is arranged immediately in advance of the place of use, especially in advance of the place of use which works up the residual combustion gases. If, as illustrated in Fig. 1, which is described n detail below, in addition to the valve arranged immediately in advance of the place of use a further valve is arranged in the conduit leading thereto in the immediate vicinity of the explosion chamber, the conduit can be closed orf against the explosion chamber prior to the formation of an ignitable mixture in the same. There results the further possibility of opening the valve arranged immediately in advance of the place of use somewhat later than the valve arranged in the vicinity of the explosion chamber, so that the time interval required for the charging and filling of the conduit with gases can be further reduced with corresponding reduction of the losses.

Referring now to Fig. 1, the numeral I indicates one of the two explosion chambers which operate alternatingly upon the same turbine wheel assemblies, which will be described below. The illustrated explosion chamber I covers the chamber fwhich is arranged parallel thereto and is constructed in the same way. For the introduction of the operating media, there is provided the hydraulically controlled air inlet valve 2. The

introduction of the, for example, liquid fuel oc-v curs by way of the nozzle 3,wh ile the supercharg ing air, which has a somewhat higher pressure than the air admitted through the valve 2, isA charged throughL the valve Il. Spark plugs v5 are. provided to ignite the so-formed combustiblel mixture in the explosion chamber I. As soon as the explosion is completed the nozzle valve 6 opens, as illustrated, andvdischargesthe high pressure portion of the explosion gases to the nozzle group 'I through which the gases impinge the bladings 8 of the wheel 9. The'partially exhausted gases, after a certain degree of pressure equalization has taken place in the pressure equalizer Ill, are conf ducted to the nozzle group Il to impinge by way of the latter the blading I2 of the wheel I3. In

View of the high charging pressure (about 10 atmospheres gauge and above) 'and the correspondingly high explosion pressure (about 45 atmospheres and above), the whole pressure head cannot be utilized eiciently in the turbines 9 and I 3,l and there is accordingly provided, in

addition to the turbine. wheels 9 and I3 and their housing I8, a second housing arrangement as shown at I5 with the nozzle groups I6 and I'I, the bladings I8 and I9 aswell as the rotors 20 and I 2I, to which ,the partially exhausted -gases are iiow to the nozzle assembly 26 by which they are directed against the turbine 28.

vAs soon as the pressure of the discharging combustion gases in the explosion chamber I has fallen to avalue which no longer permits an emcient utilization of their working content' successively in the four series-arranged bladings 8, E2, I8 and I9, the additional discharge valve 23 of the explosion chamber is opened and the nozzle.

valve 5 closed. At the same time (or shortly thereafter, as explained below) the valve 25 is opened. The second portion of the combustion gases now ows through the nozzle group 26, which is not connected with the nozzle group I6 but is arranged and constructed separately of the latter. The gases iiowing out of the nozzle group 28 then strike the blading I8 of the rotor 2D after which, together with the gases iiowing out of the nozzle group I 6 and out of the blading I8, they fiow to the nozzles I'Iarranged upon the whole housing periphery, to impinge the blading I9 .by

way of such nozzles I'I. After the second portion of the combustion gases in the explosion chamber I has in this way been expanded toa pressure which is somewhat below the pressure of the air which is admitted through the valve 2 (which may be about 3 or more atmospheres) ,the latter is opened; the entering air forms a piston-like dividing layer by reason of the venturi-like construction of the inlet cone 21 of the explosion chamber and pushes the combustion gases out of the explosion chamber I through the valve 23 approximately at the pressure of the newly entery ing air.

, The lower pressure combustion gases are thus expanded in this mode, of operation in only two pressure stages, namely in the nozzle groups 2,6 and `II and inthe corresponding bladings I8 and I9. expelled to the desired degree fromthe explosion chamber, the valve 25 is closed, the conduit 24 beingl under the then prevailing chamber pressure and remaining at approximatelysuch pressure. The valve 23 may be closed simultaneously with the valve 25 or shortly thereafter.

By the arrangement of the valve 25 at the end of the conduit 24 there is thus obtained, in accordance with the invention, the result that the pressure in theconduit v24, after completion of the expulsion of the residual combustion gases, is maintained at. the value prevailing at this-instant and nol longer falls tothe counter-pressure in the discharge pipe 22, which in general will correspond to atmospheric pressure, which would result in fall of the gas velocity to zero withconse- As soon as theresidual gases have been v lvalves 23. because the time of opening Ioi ther quent braking action by the combustion gases upon the blading of the wheels. In addition, the pressure losses occurring through throttling upon yopening of the valve 23 turn out comparatively small because the pressure drop is small. Above all, however, the whirlings leading to high heat transfers at the conduit walls can no longer take place,so that the output losses become correspondingly insignificant. A further result is the quicker lling of the conduit 24 at the moment of opening of the valve 23, which can be further reduced by delaying somewhat the opening of the valve 25 with respect to the opening of the valve 23. The valve 25 moreover, may serve for the control both of the residual gases out of the explosion chamber I as well as of the residual gases from the addi-` tional unillustrated explosion chamber. The valve 25 is actuated simultaneously with the valve 23 of the explosion chamber i and with the corresponding exhaust valve of the other, unillustrated chamber; the valve 2li-can cooperate with both valves 23 is always less than half the cycle period.

'I'he additional outlet valve 23 at the discharge end of the explosion chamber is itself known, as explained above, for making possible the working of the lower pressure combustion gases ata sepa.- rate place ofnse with a correspondingly increased e'iciency. In combination with the valve 25 proposed in mcordance with the invention, however, there arise the described advantages without the conduit 24 taking part in the charging process of the explosion chamber.

valve 23 there can be obtained, in addition, and as already indicated, a nther acceleration of the filling of the conduit 24.

In view o the usual arrangement of several explosion chambers operating upon the same rotor assembly, it possible and desirable to provide a single separate valve, arranged immediately in advancev of the place of use, for several explosion chambersV discharging lower pressure gases, including the residual combustion gases, to the same piace of use, to which valve there is suitably allotted a group or" nozzles impinging the the turbine bieding'. The elimination of the .auxiliary outlet valves at the discharge end of the chambers is of especial advantage when the location of ruher valves in the immediate vicinity of the explosion chambers is structurally dinicult and is therefore desirably avoided. A In such case, however, a separate valve should be provided for each explosion chamber at the place of utilization of they low pressure gases.

'Ihis latter arrangement is shown in Figs. 2 and 2 wherein there is provided for each explosion chamber only one valve corresponding to the valve 25 of the constructional embodiment according to Fig. l, which valve is likewise arranged as close as possible to the impinged group of nozzles. No additional valves are, however, provided at the explosion chambers, the-latter being in permanent communication with theconduits.

The reference characters l to 8 designate parts of the explosion chamber corresponding to the constructional example of Fig. 1 The high pressure combustion gases, which are discharged first through the outlet or nozzle valve i, strike in the same way the group of high pressure nozzles which is not illustrated in the gure. 'Ihe second part of the discharging combustion gases, which has only a comparatively vlow pressure, allowsY from the chamber I through the conduit 28 directly attached thereto, and byway of valve advance of the semi-circular nozzle row 3i.

By the opening of thevalve 25 later in time than the opening of the 29 to a separate group of nozzles 30. There belng no auxiliary outlet valve at the discharge end of the chamber, the connecting conduit 28 from the head of the explosionchamber I up to the valve 29 is consequently continually connected with the interior of the explosion chamber I, so that it participates both in the charging as well as in the explosion processes. Depending upon the selected mode of operation, i. e., the manner and .duration of the air and fuel charging, it can remain filled substantially only With residual combustion gases or can likewise be preferably are, constructedand arranged independently of the nozzles 3i.

For the purpose of pressure equalization there is arranged a pressure equalizing chamber 32 in The valve 29, so far as the constructional conditions Y permit, is arranged as close as possible to the semi-circular row of nozzles 3@ in order to keep the nozzle ante-chamber 33 as small as possible.A An ante-chamber 34 correspondingto the nozzle ante-chamber 33 is provided upon the opposite side of the nozzle ring in order to receive the` residual combustion gases oi the second, hot-illustrated explosion chamber by way ofthe valve 35 and conduit 36. The nozzle group B is thus alternatingly impinged by Way of the valves 29 and 35 from the explosion chamber l and the corresponding second chamber.

' It will be evident from what has been said above, that the auxiliary outlet valve 23 may or may not he employed with the valve 25 located in the immediate vicinity of the place of utilization of the lower pressure gases. It will also be clear that the gases discharging through the conduit 2d and valve 25 need not necessarily be only the residual gases in the explosion charnber, that is, the gases expelled by the incoming charge of scavenging and/or charging air; the lower pressure gases may include the explosion gases of lower pressure head than those discharging through the nozzle valve 5, but of higher pressure than the residual gases {whicli are usually of about the same pressure as the air which expels the same). In the latter case, the gases of lower pressure head will be followed out of the chamber by the cody of residual gases iilling the chamber at the moment that the air charging valve s is opened.

'I'he mechanism for' eiecting the proper tlming of the charging and discharging valves, in-

cluding the valves 25 and 2S, may take various known forms and need not, therefore, be described in. detail.` A satisfactory form of valve timing mechanism is the oil distributor disclosed in the patent to Hans HolzwarthNo- 8722194 and in later patenis to the same inventor- By a suitable arrangement uf the cil charging and discharging grooves in the surface of the rotary member of such distributor, the proper timing of the various valves to eiect the operations above described can readily be accomplished.

Various changes and substitutions can be made in the apparatus above described without departing from the spirit of the invention. Thus the valves can be operated otherwise than hydraulically, and one or more of the turbines can be replaced by other apparatus, such as an explosion boiler, capable of utilizing the explosion gases.

I claim:

1. Inthe operation of a constant volume explosion chamber plant wherein the generated combustion gases are subdivided in each working cycle with respect to pressure, quantity, or pressure and quantity, and are discharged through separate conduits to an adjacent place of use and a remote place of use, the step which comprises continuously maintaining the conduit leading to the remote place of use at a higher pressure than that prevailing at such place of use throughout the extent of such conduit and substantially to the place of use.

2. Process according to claim 1, wherein the expansion of the combustion gases discharging .during each cycle from the conduit leading to the remote place of use is terminated before the pressure in such conduit has fallen to the pressure prevailing at the place of use.

3. Process according to claim 1, wherein the conduit leading to the r-emote place of use is closed with respect to the explosion chamber prior to the formation of an ignitable mixture in the same as fuel and air are charged into the chamber.

4. Process according to claim 1, wherein the conduit and the remote place of use are brought into communication only after communication has been established between the explosion chamber and the conduit.

5. In combination, a constant volume explosion chamber, air and fuel inlet valve means associated with the chamber, a nozzle valve for discharging the high pressure explosion gases, a high pressure turbine arranged to be driven by said gases, a conduit for leading the lower pressure gases from' the chamber to a lower pressure turbine, an auxiliary valve for controlling the discharge of the gases of lower pressure ranges through said conduit after the discharge of the higher pressure explosion gases from the chamber, said auxiliary valve being arranged substantially immediately in advance of the lower pressure'turbine, and operating mechanism for,

the valves timed to cause closing of the auxiliary Vvalve while the pressure in the conduit is still considerably higher than the back-pressure n the lower pressure turbine, whereby a reduced or no pressure diierence between the chamber and conduit exists when the lower pressure gases begin to be discharged through said conduit during the next cycle.

6. Apparatus according to Yclaim 5, including an additional valve arranged in the immediate vicinity of the explosion chamber and controlling the said conduit, said valve operating mechanism being constructed to cause opening of such valve in advance of the auxiliary valve.

'7. In combination, a plurality of constant volume explosion chambers, air and fuel inlet means associated with said chambers, outlet valve mechanism associated with each of said chambers for discharging the high pressure explosion gases, separate conduits leading from said chambers to the same place of use of the lower pressure gases thereof whereat the pressure of such gases is reduced, a single auxiliary valve for all of said chambers and controlling the discharge of residual gases therefrom, said auxiliary valve being arranged immediately in advance of the common place of use of the residual gases, and operating mechanism for the valves timed to cause closing of theauxiliary valve while the pressure in the conduit of a discharging chamber is still considerably higher than the back-pressure on the turbine,

whereby a reduced or no pressure difference between the chamber and the conduit exists when the lower pressure gases begin to be discharged through said conduit during the next cycle.

8. Apparatus according to claim '7, including additional valve mechanism at the discharge end of the explosion chambers controlling the discharge of lower pressure range gases into said conduits.

9. In an explosion turbine plant, the combination of a constant volume explosion chamber, air

and fuel inlet means associated with the chamber, an outlet valve for discharging the high pres'- sure explosion gases from the chamber, appara-` tus arranged to be operated by said high pressure gases, a turbine operatedby gases of lower pressure range, a group of nozzles receiving the exhaust gases discharging from said apparatus l and arranged to direct them against said turbine,

a relatively long conduit leading from the explosion chamber for conveying the gases of lower pressure range of the chamber to said turbine, an auxiliary valve disposed in said conduit immediately in advance of said turbine, a group of expansion nozzles for directing the residualgases against theturbine, said last-mentioned nozzle group being arranged and constructed independently of the rst group of nozzles, and valve operating mechanism for the valves timedto cause closing of the auxiliary'valve while the pressure in the conduit is still considerably higher than the back-pressure on the turbine, whereby a re duced or no pressure difference between the chamber and conduit exists when the lower pressure gases begin to be discharged through said conduit duringthe next cycle.

10. An explosion turbine plant as defined in claim 9, wherein the auxiliary valve is associated with two explosion chambers.

11. In the operation of a constant volume explosion chamber plant provided with a nozzle valve for the discharge of the high pressure explosion gases to an adjacent place of use and with a relatively long conduit leading to a more remotely situated turbine utilizing gases of lower pressure, the steps which comprise opening the charge in the chamber to effect discharge of the gases of high pressure head, causing the pressure in the conduit, up to a point immediately in advance of the nozzle of said turbine, to reach a value corresponding to that of the gases of lower pressure head remaining in the explosion chamber, and subsequently eiecting discharge o'f the gases of lower pressure through the conduit to 'nozzle valve after the explosion of a combustible the place of utilization of gases of lower pressure.

the gases of high pressure head have been discharged, charging the lower pressure gases into the turbine through said conduit, charging air f asoman under pressure into the explosion chamber while the chamber and conduit are in communication with each other to effect expulsion of th'e residual gases in the chamber through the conduit and into the turbine, and closing the conduit in the immediate vicinity of the turbine while the conduit is at a pressure considerably above the back pressure on the turbine.

13. In combination, a constant volume explosion chamber, air and fuel inlet means associated with the chamber, a nozzle valve for discharging the high pressure explosion gases, a conduit leading from such nozzle valve to a place of utilization of the gases of high pressure head, a gas turbine located more remotely from the chamber than said place of utilization, a secondl conduit leading from the chamber to said turbine.

an auxiliaryvalve arranged at the end of said f second conduit and substantially immediately in advance of the turbine, and valve operating mechanism timed to effect closing of the said auxiliary valve while the gases discharging therethrough are considerably above the back pressure on the turbine.

14. Apparatus according to claim 13, wherein the second conduit is in constant communication with the discharge end of the explosion chamber.

15. Apparatus according to claim 13, wherein the second conduit is provided with an auxiliary outlet valve at its point of communication with the chamber, said valve operating mechanism acting to open the auxiliary outlet valve after the discharge of the higher pressure gases is completed and shortly before the opening of the first-men- 35 tioned auxiliary valve.

16. Apparatus according to claim 13, wherein the auxiliary valve i's common to the lower prestsuere discharge conduits oi two explosion cham- 17. An explosion turbine plant comprising, in combination, a constant volume explosion chamber, air and fuel inletvalve means associated with the chamber, a nozzle valve for discharging the high pressure explosion gases, a high pressurey turbine arranged to be driven by said gases, a lower pressure turbine arranged upon thesame side of the chamber as the iirst turbine and more remote from the outlet end of the chamber than -such ilrst turbine, a relatively long conduit for leading the gases of lower pressure range from the chamber tothe lower pressure turbine, an auxiliary valve controlling the discharge of the lower pressure range gases through said conduit after the discharge of the higher pressure explosion gases from the chamber, said auxiliary valve being arranged substantially immediately in advance ot the lower pressure turbir. and operating mechanism for the valves timed to cause closing of the auxiliary valve while the pressure in the conduit is still considerably higher than the back-pressure on the lower` pressure turbine, whereby a reduced or no pressure dierence between the chamber and the conduit exists when the lower pressure gases begin to be discharged through said conduit during the next cycle.

18. An explosion turbine plant as deilned in claim 17, including a conduit for leading the gases exhausting under pressure from the nrst turbine into the second turbine.

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