US1948540A - Steam generator - Google Patents

Description

Shelets-Sheet l HTTURNEY Feb. 27, 1934. w. G. NoAcK .STEAM GENERATOR original Filed Aug. 2o. 19:51

Feb. 27, 1934.

w. G. NoAcK STEAM GEERATOR Original Filed Aug. 20, 1931 2 Sheets-Sheet 2 Patented Feb. 21, 1934 ,I l f t 1,948,540*

UNITED STATES4 PATENT OFFICE STEAM GENERATOR Application August 20, 1931, Serial No. 558,262, and in Germany September 1, 1930. Renewed October 14, 1933 v l 11 crains, (o1. 12e-511)V This application is a continuation in part/oi! thereof, the tubes being surrounded by a cylinmy copending applications `Serial No. 343,745, drical outer wall 8. The tubes 7 are connected beled March 1, 1929 and Serial No. 375,138, illed tween the water inlet chamber and the water July 1, 192.9. outlet chamber 6 to pass water that is heated and l The present invention relates to steam generavaporized while passing through the tubes, the 80 tors of the type in which a combustible mixture mixture or -hot water and steam being discharged is subjected to combustion under pressure ,in a through a conduit 10 into a steam separator 11, combustion chamber, and the pressure is utilized the steam separating and collecting in the upper to impart to the hot combustiongases a velocity part of the separator from where it isd supplied Vl0 `oi the order of about 200 meters per second or to the load, and the water being Collected in the 85 more at which the compressibility of the gases belower part of the Separator, reSh feediweter becomes effective through the inlets oi aset of gas ing Supplied thereto through pipe 12- nThe Water Y tubes of a heat exchanger passing a steam generfrom the separator 11 is circulated through water ating fluid around the Itubes for generating steam tubeS 7 by means of Water Dump 13 Which iS con* 15 therein. The present invention provides an im- 'neeted by pipes 14 between the separator 11 and 70 proved arrangement of the gas tubes in such inlet 15 0f Wetel Chamber 5- steam generator which greatly reduces the pres- A combustible charge, such as a gas or air with sure needed for discharging the gases at the refuel admixed thereto, is compressed by compresquired high velocity. sor end delivered to combustion chamber 1 20 `The objects of the invention will be best underthrough Conduit 21 and o Suitable inlet 22- The 75 stood from .the following description of exempliadmitted compressed combustible charge is subcations thereof, reference being had to the ac- .ieoted to Combustion in the Chamber. The Dresoompanying drawings, wherein sure of the hot combustion gases is utilized to Fig. 1 is a diagrammatic view of a steam gendrive the gases at a velocity of about 200 meters erator with a combustion chamber made in acper Second 01' above through a Set of SaS or lre 80 cordance with the invention; and tubes 26 connected to the upper end of the cham- Figs. 2. 3 and 4 are detailed sectional views of `ber and leading through the interior 0f the water different modifications oi the gas discharge tubes tubes 7, the gases being discharged into the gas embodying the invention. outlet duct 27, and therefrom, through pipe 28 30 In Fig. l is illustrated a steam generator of into a gas turbine Where e Dart of the energy Still 85` the type illustrated in my copending prior appliremaining in the gases is applied to drive comcations Serial No. 343,746, filed March 1`, 1929 and presser 20 and thus serves to initially compress Serial No. 414,428, led December 16, 1929, in the combustible charge supplied to the chamber. which an extremely high rate of steam generation Additional driving power may be Supplied to the is secured by subjecting a combustible charge compreSSor by er1-auxiliary motor 30, such as a. 9o to combustion under pressure in a pressure-proof Steam engine or DieSel engine, Coupled to the gas chamber and utilizing the pressure of the hot turbine 29, the total power Supplied by the motor combustion gases formedin the chamber for imand the turbine being proportioned to be Suffiparting to said gases a very high .velocity through cient to produce in the compressor the pressure a set or gas tubes traversed on the outside by a head necessary for importing to the combustion 95 steam generating fluid, such as water, thereby geSeS the high Velocity ond for driving the uuXlsecuring a very high rate of heat transference lary gas turbine to Supply a part or all 0f the from the hot gases to the water and, as a conseinitial charging pressure. quence, very large steam generationv within av The combustion within the chamber 1 may be relatively small structure. carried on either as a continuous process, in which 10o The steam generator comprises a pressure-A case the in1et12 forms a burner at which a conprooi combustion chamber 1 having a main cytinucusly supplied compressed charge is continlindrical section 2 with an inlet header 3 enuously burned within the chamber; or, the comclosing the' bottom and an outlet header 4 enbustion may be carried on as a periodical process closing the top of the chamber. Within the walls like in a combustion engine. in which CaSe the in- 10'5 of the inlet header 3 is formed a water inlet 4let 12 is arranged as a' valve which periodically chamber 5 and within the walls of the outlet opens and admits an initially compressed charge header 4 is formed a water outlet'chamber 6. A which is then exploded in the chamber, as by set oi! water tubes 'I is mounted along the periphspark plugs mounted within the chamber, the

55 ery of the chamber 1 forming the, inner wall! procese beine eyouoelly repeated nd the Pres' 11 sure of the generated hot combustion gases imparting to them the high velocity through the gas tubes 26. Considerable pressure drops must be available in the gases Within the chamber in order to produce the high iioW velocities of the gases through the gas tubes. For reasons of economy it is important that this pressure drop shall be as low as possible.

In accordance with the present invention, production of high gas velocities through gas tubes with small pressure drops is made possible by prou vision of nozzles 32 at the inlets of the gases into the gas tubes 26 and of diffusers`33 at the outlets, as shown in Fig. 1, and with more detail in Fig. 2. The nozzle 32 is so shaped that the pressure efficiently imparts to the combustion gases the high velocity already at the entrance into the tube 26, that is, at the place where the combustion gases are still at the maximum temperature, so that relatively small diiferences in pressure will already sufhce for producing considerable heat drops and consequently high velocities of flow. In just the opposite way, the outlet end of the gas tube terminates into a widening diffuser 33 in which the still high velocity of the gases is reconverted into pressure. Since the gases passing the end portion of the gas tube are already considerably cooled down, and have greater density, they can, at a given velocity of ow, overcome a greater pressure ratio in the diffuser than that which was required to impart such velocity to the hot gases in the nozzle. By cooling the gases in the gas tubes and generating steam with the heat derived from the gases, it would thus be theoretically possible to produce with the diffuser, without any external compression Work, not only the pressure drop required for producing the high velocity gas ow, but even a certain excess pressure. This is not fully the oase in practice, because the compression work in the diiuser is effected with a far lower degree of eiciency than the imparting of the velocity in the nozzle, and also because, notwithstanding the rate of heat exchange obtained, the transfer of the heat from the gases to the fluid around the tubes requires a tube length at which the tube resistance becomes appreciable. The provision o1" a nozzle at the inlet and a diffuser at the outlet of the gas tubes as described above makes possible a very considerable reduction of the pressure difference required to produce the high velocity gas iiow, and thus enables reduction of the compressor work for initial compression of the charge. With regard to the amount of the tube resistance, consideration is also to be given to the fact, that the diminution fin velocity caused by the cooling of the gases likewise results in a recompression effect like that produced in the dif- Iuser, this recompression being equivalent to a reduction of the tube resistance.

The fire tubes of the steam generators made in accordance with the invention may have different forms. In the construction shown in Figs. 1` and 2, the re tube 26 is throughout its length of uniform cross section, for instance, cylindrical in shape, with the nozzle 32 at the inlet to eciently impart to the hot combustion gases their full velocity at the entrance in the tube, and a diffuser at the outlet for reconverting the velocity of the outflowinggases into a pressure head which assists in imparting the high velocity to the gases and reduces the amount of pressure that must initially be imparted to the charge. Because of the uniform cross section of the tube, the velocity of the owing gas decreases to some extent along the tube, in accordance with the decrease of the absolute temperature of the gases in the tube.

In the construction shown in Fig. 3, the fire tube 35 decreases in cross section in the direction of gas ow, being also provided with a nozzle 36` and a diffuser 37 like that of Fig. 2. The diminution in cross section may be proportioned to cause the velocity to remain constant throughout the length of the tube from the nozzle till the narrowest point at the junction with the diffuser 37. The diminution of the cross section may be 0btained in a simple way by flattening a circular tube to make it increasingly oval towards the outlet end.

In Fig. 4 is shown a re tube 38 which is, as a whole, constructed as a diffuser, the tube gradually increasing in cross section from the point where it joins the nozzle 39 at its inlet, and acting as the heating surface for transmitting the heat of the gases to the surrounding Water.

The re tubes are preferably made as nearly straight as possible. Only the velocity of the gas is slowed down and converted into pressure within the diffuser, and solid particles, such as ashes, owing with the gas do not take part in the change in velocity. This feature is utilized for separating ash and clinker from the gases discharged through the nre tubes. To this end the diffuser ends are arranged in the gas outlet duct 27, as shown in Figs. 1 and 2, to permit lateral outiiow of the slowed down gases, diverting the relatively high velocity ash and clinker particles from the gas, and collecting them in a space at the bottom of the gas duct 27.

The high velocity gas ow at reduced combustion chamber pressure is maintained by the pressure gain in the diffuser only as long as the diffuser operates correctly. As in case of other devices which operate according to similar dynamic laws, the gas iow through the diffuser may become interrupted and the vacuum destroyed. In order to keep the nre tube in proper operating condition notwithstanding such interruption, means are provided for regulating the pressure ratio in the nozzle 32 or in the diffuser 33 by inuencing the control of the motor 30 which drives the compressor 20 in accordance With the pressure of the gases after the nozzle or before the diffuser. This is shown in Fig. 1, where a pressure-responsive device 34 mounted on the fire tube 26, before the diffuser 33, regulates through line 35 the admission of driving energy, such as steam or fuel, to the auxiliary compressor motor 30 to speed up the compressor and increase its pressure if the pressure ratio in the diffuser diminishes. In this way, an interruption of the gas discharge in the tubes, orl a decrease of its velocity, will immediately produce an ini crease of the chamber pressure, increasing the gas velocity and the pressure ratio in the nozzle and diffuser. On restoration of the correct working conditions, the speed of the compressor setv is automatically brought back to normal.

Many other modifications of the invention will suggest themselves to those skilled in the art and I desire, accordingly, that the appended claims be given a broad construction commensurate with its scope in the art.

I claim:

1. The combination with a steam generator comprising a pressure-proof combustion chamber, and means for supplying a combustible charge to said chamber and for subjecting said charge to combustion within said chamber to produce hot combustion gases of a pressure higher than the external pressure, of a heat exchanger having a plurality of gas tubes connected to said chamber and arranged to cause the pressure within the chamber to impart to the hot combustion gases a velocity of about 200 meters per second or more through nozzle-like entrances into said tubes, tubular enclosure means surrounding said tubes for passing a steam generating uid at a pressure higher than the external pressure, the inlet ends of said tubes having nozzle-like constrictions to impart to the combustion gases said high velocity at the entrance into the tubes, and the outlet ends of said tubes being diffuser-like enlarged, increasing in cross section in the direction of the gas now to slow down the outflowing gases and utilize their velocity for increasing the pressure at the outlet ends of the tubes above the pressure value in the portions lying back of the outlet points.

2. The combination with a steam generator comprising a pressure-proof combustion chamyso ber, and means for supplying a combustible charge to said chamber and for subjecting said charge to combustion within said chamber to produce hot combustion gases of a pressure high- -er than the external pressure, of a heat exchanger having a plurality of gas tubes connected to said chamber and arranged to cause the pressure within the chamber to impart to the hotl combustion gases a velocity of about 200 meters per second or more through nozzle-like entrances into said tubes, tubular enclosure means surrounding said tubes for passing a steam gener-4 ating fluid at a pressure higher than the external pressure, constricted nozzles at the inlet ends of said tubes to impart to the combustion gases said high velocity at the entrance into the tubes, and divergent diiusers at the outlets of said tubes increasing in cross section in the direction of the gas flow for slowing down the outflowing gases and building up a pressure assisting in imparting the high velocity at the inlet side of the tubes. '3. The combination with a steam generator comprising a pressure-proof combustion chamber, and means for supplying a combustible charge to said chamber and for subjecting said charge to combustion within said chamber to produce hot combustion gases of a'pressure higher than the external pressure, of a heat exchanger having a pluralityof gas tubes connected to said chamber and arranged to cause the pressure within the chamber to impart to the hot combustion gases a velocity of about 200 meters per second `or more through nozzle-like entrances into said tubes, tubular enclosure means surroundingA said tubes for passing a steam generating fluid at a pressure higher than the ex-l 'let sides of the tubes, thetube portions .lying between the nozzles and the diiusers, decreasing in cross section in the direction of the gas flow.

4. `The combination with a steam generator comprising a pressure-proof combustion chamber, and means for supplying a combustible* charge to said chamber and for subjecting said charge to combustion within ysaid chamber to produce hot combustion gases of a pressure higher than the external pressure, of a heat exchanger having a plurality of gas tubes connected to said chamber and arranged to cause the pressure within the chamber to impart to the hot combustion gases a velocity of about 200 meters lper second or=more through nozzle-like entrances into said tubes, tubular enclosure means surrounding said tubes for passing a steam generating fluid at a pressure higher than the external pressure, and constricted nozzles at the inlet ends of said tubes to impart to the combustion gases said high velocity at the entrance into the tubes, said tubes being of divergent diffuser-like shape, increasing in cross section in the direction of the gas ilow.

5. The combination with a steam generator comprising a pressure-proof combustion chamber, and means for supplying an initially compressed combustible charge to said chamber and for subjecting said charge to combustion within 'the pressure within the chamber to impart to the hot combustion gases a velocity of about 200 meters per second or more through nozzle-like entrances into said tubes, tubular enclosure means surrounding said tubes for passing a steam generating fluid at 'a pressure higher than the external pressure, the inlet ends of said tubes having'nozzle-like constrictions to impart to the combustion gases said high velocity at lthe enrance into the tubes, the outlet ends of said tubes being diffuser-like enlarged, increasing in cross section in the direction of the gas flow to slow down the outflowing gases and utilize their velocity for increasing the pressure at the outlet ends of the tubes above the pressure value in the portions lying back of the outlet points, and means responsive to the pressure conditions of the gas in the tube for controlling the initial compression of the charge supplied to said chamber.

6. The combination with a steam generator comprising a pressure-proof combustion chamber, means including a compressor for supplying an initially compressed combustible charge tol said chamber and for subjecting said charge to combustion within said chamber to produce hot combustion gases of a pressure higher than the external pressure, and a motor for driving said compressor, of 'a heat exchanger having a plurality of gas tubes connected to said chamber and arranged to cause the pressure within the chamber to impart to the hot combustion gases a velocity of about 200 meters per second or more through nozzle-like entrances into said tubes, tubular enclosure means surrounding said tubes for passing a steam generating fluid at a pressure higher than the external pressure, the inlet ends of said tubes having nozzle-like constrictions to impart to the combustion gases said higher velocity at the entrance into the tubes, the outlet ends of said tubes being diiiuser-like enlarged, increasing in cross section in the direction of the gas ilow to slow down the outowing gases and utilize their velocity for increasing the pressure at the outlet ends of the tubes above the pressure value in the portions lying back of the outlet points, and means responsive to the pressure conditions of the lgas in an end portion o! a tube for increasing the compression of the roo charge supplied to the combustion chamber in response to decrease of the tube gas velocity.

7. A steam generator comprising a pressureproof combustion chamber, means for supplying a combustible charge to said chamber and for subjecting said charge to combustion within said chamber to produce hot combustion gases of a pressure higher than the external pressure, said hot combustion gases including light solid particles, a heat exchanger having a plurality of gas tubes connected to said chamber and arranged to cause the pressure within the chamber to impart to the hot combustion gases and the solid particles carried therein a velocity of about 200 meters per second or more through nozzle-like entrances into said tubes, tubular enclosure means surrounding said tubes for passing a steam generating iiuid at a pressure higher than the external pressure, and means at the outlet ends of said tubes for slowing down the velocity of the outowing gases while maintaining relatively high velocity of the solid particles moving with the gas to separate the solid particles from said outowing gases.

8. A steam generator comprising a pressureproof combustion chamber, means for supplying a combustible charge to said chamber and for subjecting said charge to combustion Within said chamber to produce hot combustion gases of a pressure higher than the external pressure, said hot combustion gases including light solid particles, a heat exchanger having a plurality of gas tubes connected to said chamber and arranged to cause the pressure within the chamber to impart to the hot combustion gases and the' solid particles carried therein a velocity of about 200 meters per second or more through nozzlelike entrances into said tubes, tubular enclosure means surrounding said tubes for passing a steam generatingv Yiiuid at apressurehigher than the external pressure, said tubes having divergent diffuser-like outlets, increasing in cross section in the direction of the gas flow to slow down the outflowing gases While permittinggetainer of substantially higher velocity by the solid particles present in the outflowing gases, and'means at the outlet ends of said tubes for diverting the slowed down outflowing gases from the path of the outflowing high velocity .solid particles to separate the same from the gas.

9. The method of generating steam for supplying a steam consuming load, which comprises initially compressing a gaseous body and forming therewith a combustible charge of a substantial raisedpressure, subjecting said charge to combustion under pressure within a pressureproof combustion chamber, applying the pressure within said chamber for imparting to the combustion gases at nozzle-like entrances of a Laisser) set of heat exchanger tubes a velocity of about 200-meters per second or more through said tubes, passing a steam generating uid around said tubes to absorb heat from the gases and generate steam, and applying the velocity of the combustion gases passing through said tubes, in diffuser-like outlet portions thereof, to recompress the outowing gases and supply in the outlet portions of said tubes a part of the pressure drop for imparting to the gases the initial velocity at said nozzle-like tube entrances. l

10. A vapor generator comprising a pressureproof combustion chamber, means for supplying a combustible charge to said chamber and for subjecting said charge to combustion within said chamber to produce hot combustion gases of a pressure higher than the external pressure, heat exchange means holding a vaporizable liquid and having a set of heating tubes connected to said chamber for discharging the hot combustion gases from said chamber, the chamber inlet ends of said tubes having constricted inlet nozzles constructed and proportioned to apply the pressure of the gases for driving the hot gases from said chamber through said inlet nozzles into the tubes at a velocity of the order of about 200 meters per vsecond or more to heat said liquid and generate steam, and the outlet ends of said tubes being diffuser-like enlarged, increasing in cross section in the direction of the gas flow to slow down the outflowing gases and utilize their velocity for increasing the pressure at the outlet ends of the tubes above the pressure value in the portions lying back of the outlet points.

l1. A vapor generator comprising a pressureproof combustion chamber, means for supplying a combustible'charge to said chamber and for subjecting said charge to combustion within said chamber to produce hot combustion gases of a pressure higher than the external pressure, heat exchange means holding a vaporizable liquid and having a set cf heating tubes connected to said chamber for discharging the hot combustion gases from said chamber, the chamber inlet ends of said tubes having constricted inlet nozzles constructed and proportioned to apply the pressure of the gases for driving the hot gases from said chamber through said inlet nozzles into the tubes at a. high velocity above 100 meters per second or more to heat said liquid and generate steam, and the outlet ends of said tubes being diffuser-like enlarged, increasing in crosssection in the direction of the gas ilow to slow down the outflowing gases and utilize their velocity for WALTER GUSTAV NOACK.

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