US1545668A - Steam generator - Google Patents

Description

July 14', 1925. 1,545,668

' W. D. LAMONT STEAM GENERATOR Filed Dec. 28, 1918 3 Sheets-Sheet 1 w. D. LA MONT STEAM GENERATOR Filed Dec. 28, 1918 3 sheets-sheet 2 July 14, 1925. I 1,545,668

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Patented July '14, N925.

' UNITED STATES PATENT oFFlca;

WALTER DOUGLAS LA MONT, OF THE UNITED STATES NAVY, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, '.I.O LA MONT WASTE HEAT STEAM GENERATOR COR- IPORATION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

STEAM GENERATOR.

Application filed December as, 1918. SerialNo. 268,651.

To all whom it may com/em:

Be it known that I, WALTER D. LA MONT, United States Navy, a citizen of the United States, residing at Annapolis in the county of Anne Arundel, State of Maryland, have invented certain new and useful Improvements in Steam Generators, of which the following is a description, reference being had to the accompanying drawings, forming a part hereof.

My invention relates to methods of and means for generating steam and has'for its object a method of generating steam by which steam at high pressure adapted for use in steam engines may be generated quickly from a small amount of water constantly supplied so that-the weight of water carried in the generator during the process of generating the steam will be the least possible and will add as little as possible to the Weight of the generator itself. The invention also has for its object to provide a steam generator adapted to carry out the method described which will be simple in construction, compact and of relatively light weight and will be adapted to effectively and safely generate steam rapidly and at high pressure from a relatively small V amount of water.

v The advantages of a steam engine for this My invention is particularly intended for generating steam for a steam engine for use in driving the propeller of an aeroplane.

purpose over the-explosion engine, particularly as regards possibility of continuous operation for many hours, long life of the engine as a whole, freedom from vibration and the fatigue of the metal of the engine shaft and other parts affected by vibration, as well as other advantages, have long been recognized but it has not heretofore been found possible to produce an engine and generator, which, when in operation, that is with water in the generator, would be sufiiciently light in weight to be'used. The dilficulty so far as the engine itself is concerned has been overcome,-it being possible to construct engines of the turbine type which are sufficiently light in weight per horse power furnished for use in an aeroplane; and the condenseralso presents no difliculty at it is possible to design a condenser of the honeycomb type s'ufliciently light for the purpose. The serious difiiculty has been in the generator. Generators which have been constructed of relatively light weight in themselves have been found when in use, .that is, when supplied with the water necessary for effective operation, of a weight much too great to permit of their being used in an aeroplane.

By the use of my invention it is possible to generate steam in suflicient quantity and at sufficient pressure to effectively operate the engine of an aeroplane without exceeding a weight, for generator and the water contained in it during the process of generating steam, which is well within the limit permissible for use in aeroplanes and it is also possible to superheat the steam generatedso as to deliver it to the engine at any temperature and pressure desired.

With the above described objects and others hereinafter set forth in view, my invention consists in the method of and means for generating'steam hereinafter described and particularly pointed out in the claims.

' Referring to the drawings- Figure 1 is a longitudinal vertical sectional view of a steam generator adapted to carry out my method and embodying my means section of the same on line 6-6 of Figure 5.

Figure 7 is side elevation of a portion of the spraying nozzle strip and Figure 8 is a cross-sectional view of the same in line 88 of Figure 7.

Figure 9 is a bottom plan view of a portion of the spraying nozzle strip shown in Figures 7 and 8. p

Figure 10' is a top plan view of a of the spraying nozzle strip.

Figure 11 is a side elevation of a portion portion of the lining tube for .the distributing tube and Figure12 is a cross-section of the same on line 12-42 of Figure 11.

It. should be understood that so far as concerns the method the drawings are illustrative merely and are not intended to limit the inyention to the use of the apparatus shown or to any particular form or construction of apparatus. 7

In the drawings, 1 indicates a distributing tube at the upper end of the generator closed at one end and having connected to it at the other end by coupling 2 a pipe 3 leading from a header pipe 4: to which leads a water supply pipe 5 from a feed pump 6, preferably a centrifugal pump. 7 indicates a collectin pipe near the lower end of the generator 0 osed at one end and connected at its other end by coupling 8 to a. pipe 9 leading to a header pipe 10 fro-m which a pipe 11 leads to a separator 12 for separating the steam from the water discharged from the collecting pipe7. From this separator a pipe 13 leads upward to the engine, not shown, but preferably of the turbine type, and from the lower end of the separator a suitably valved pipe 14: leads to the pump 6 to take the water separated from the steam back to the pump to be again supplied to the distributing pipe 1.

From the distributing pipe 1 to the collecting pipe 7 extend a series of generator tubes 15 suitably secured by welding or otherwise at their ends in the pipes 1 and 7. In actual construction, each of these tubes is 15 feet long, is one-half inch in exterior diameter, of seamless drawn steel with walls twenty-eight thousandths of an inch thick but, of course, the length and diameter and other dimensions may be varied as desired. These tubes are arranged at equal distances apart along the tubes 1 and 7, preferably so that their outer surfaces will be separated ,one from the other approximately onefourth inch. In the construction shown, there are six of the distributing tubes 1 and collecting tubes 7, each distributing tube being connected with the header pipe l and .each collecting tube being connected to the the header pipe 10. For compactness alternating distributing pipes are elevated above the intermediate ones, the same arrangement being followed with the collecting pipes. The tubes 15 connected with one distributing pipe 1 are arranged opposite the spaces between the tubes 15 connected with the next adjacent distributing pipe.

The tubes 15 with their distributing pipes and collecting pipes are enclosed in a suitable casing 16, preferably open at the top and corsisting of kieselguhr composition on a wire netting. This casing extends below the collecting tubes 7 to form a combustion ing tube.

usuallybe expected the weight of the gen- 1 erator in operation would be too great to permit of its use on an aeroplane. In order to avoid the filling of the tubes with water and thus avoid the consequent weight as well as to secure other important advantages hereinafter more fully set forth, I provide, in accordance with my invention, for so distributing the water in each of the tubes 15 thatit will form a thin coating or film on the inner surface of each tube, which will be maintained as a continuous film from the distributing tube 1 to the collecting tube 7, or nearly to the collecting tube if it is desired to superheat the steam as hereinafter explained, so as to leave a central passage open at its lower end into which the steam generated from the film may escape as it is formed and may pass freely to the collect- By reason of the fact that the water is thus in a thin layer or film, steam is generated rapidly and it is found possible to evaporate a much greater amount of water per unit of surface. per unit of time than would be possible to evaporate if the tubes were filled with water, and it is also possible to deliver the steam downward without an excessive amount of water.

The steam thus generated is, of course, under pressure which is maintained by the resistance of the turbine or other engine in which the steam is used and as it has its outlet only from the lower end of the tube, it is necessarily maintained in the tube as a column having its upper end towards the upper end of the tube and inthe path of the water coming from the nozzle. As steam has, as compared with water, little or no tendency to adhere to a metal surface, this column of steam will locate itself centrally in the tube, the water coming from the nozzle, by reason of its inherent tendency to adhere to a metal surface, clinging to the walls of the tube, filling the annular space between the column of steam and these walls and forming the fihn as described, this film extending downward towards the lower end .of the tube a distance depending on the amount of water supplied and extending to the lower end of the tube if the quantity of water supplied is greater than v the amount evaporated as will ordinarily be the case.

From the foregoing description it will be noted that the method of generating steam of the present invention differs essentially from that employed in the so-called flash boilers orgenerators in which the water is sprayed against-highly heated surfaces in quantity only suflicient to insure substantially instantaneous complete volatilization, thermostatic means being usually provided to efi'ect an automatic control of this quantity. a

Among the advantages of the method of the present invention is that the eration of the steam from a film on the lnner wall of the tube in contra-distinction to the explosive action 'of flash generation is more uniform and continuous and does not require the careful regulation that is necessary with the flash boiler. Moreover, the present. invention" permits the employment of relatively thin tubes, permitting a very rapid heat exchange without danger of the tubesbeing burned out, the film of water protecting the tubes against this.

When the generator of the present invene tion is operated in the preferred manner, thefilm is caused to extend substantially to the lower end of the tube so that water and,

.steam are discharged together at this end,

. thereby avoiding any necessity for accurate control of the'water'feed which, as above pointed out, is requisite in flash boilers. The generator of the esent invention opcrates with. a very high degree of efiiciency under varying demands with a minimum I control of the water feed.

There are thus combined in this steam generator the advantage of light Weight incidental to the'u'se of relatively small quantities of water in the generatin tubes in the feed .to meet varying process of steam generation, t e advantage of protection afforded to the tubes by the mamtenance of a film of water on the inside thereof during the generation. of the steam, and the advantage of doin away with the necessity for careful variatlon of the Water the generator.

For the purpose of causing the water to be introduced into the tubes in such manner as to form afilm on the interior surface of the tubes, any convenient form of dis tributing or spraying device which will cause the water'to sprayed against the the device ,which I large diameter directly above the'tube 15 having a discharge orifice, 21 of relatively small diameter in line with the axis ofthe tube,in which the 'water is admitted to the I chamber through passages 22 arranged at tangents to 'the periphery of the chamber so as to cause the water as it enters the chamher to whirl or rotate and to be discharged through the orifice 21 as a rotating stream throwing the water as acentrifugal spray against the walls of the tube. The chamber 20 is preferably formed in a solid piece of demands made upon semicircular strip 24 and form in this lower or convex surface the tangential passages 22 as grooves leading from the passages 23 which extend through the strip to the upper or flat face. This semicircular strip fits within a tube '25 which fits within the distributing tube 1 and has formed in it at such intervals that when in position each one will be in line with the axis of a tube 15, the discharge orifices 21. 'The semicircular strip 24 is held. in position in the tube 25 by a semicylindrical locking strip 26 or by other convenient means. The diameter of the chamber 20 is preferably about one-fourth of an inch-in diameter but may be larger.

The discharge orifice 21 is preferablyabout orifices 21 in the form of a centrifugal spray thrown outward against the walls of the tubes and "forming on these walls a thin layer or film. So long as the pressure on the waterexceeds the pressure of steam in the tubes water will; be forced into the ends of the tubes and will form a film as described and this film will extend as a continuous film throughout the'l'ength o f the tube or such part of the length of .the tube as ma ,be desired, depending on the excess of te pressure on the water over the pressure of the steam generated. -For'ordinary purposes the pressure on thewater should be such that the film .Will extend to the lower ends of the generator tubes and water and steam will be discharged together into the collecting tubes, In a generator in which steam is to be generated at a pressure of 800 pounds it is desirable to use a pressure on the water i of 200 pounds inexcess of the 800 ,pounds that is at 1000 pounds. If itais desired-to superheat the steam the pressure on the water is reduced so that the filni will not extend to the lower ends. of the generator.

tubes so that the steam generated. from the film will come in contact with are walls of the generator tubes below the 'film and in the collected tubes and will be superheated'by such contact.

From the collecting tubes the water and ture at which it came from the generator and is returned to the distributing tubes at substantially this temperature, thus entering the generator tubes highly heated. If the steam is superheated, as above described,

there will, of course, be no water to be sep arated from the steam and the feed pump will be supplied from the condenser.

The high pressure of the steam, in the generator tubes stiffens the tube against any tendency of the tube to buckle from any unevenness of heating. The free escape of the steam, as it is'generated through the passage at the center of the tube, facilitates the rapid and continuous evaporation of the water and thus permits of and necessitates a very rapid feed in order to maintain the film throughout or substantially throughout the length of the generator tubes. water is thus required to and does circulate rapidly incontact with the heated surfaces of the tubes, acondition which facilitates efi'ective generation.

The length of the generator tubes corresponds to the vertical distance between the two planes of the biplane on which it is to be used, the open upper end of the casing 16 extending through the upper plane so that the products of combustion will be discharged above this upper plane. The relatively great lengths of the generator tubes permits of utilizing a very high percentage of the heat produced by the burners.

While, as above stated, the invention is particularly adapted andin-tended for use in connection with aeroplane engines, it is ob viously adapted for use in connection with steam generators for other purposes and may readily be adapted to any water tube type of boiler in which the tubes are arranged other than horizontal, that is, are so arranged that one end is substantially higher than the other so that the film formed on the interior of the tubes will be free to move downward and will be aided in its movement by gravity. i

. Claims to certain separable subject matter common to this application and to my coplendingapplication, Serial No. 32,06 t filed ay 22, 1925, will be made in my said copending application.

Having thus described my mventionwhat I claim is:

1. The'method of generating steam, which consists in forcing water into the upper end The of a heated tube having. one end higher than the other,*and directing the water toward the wall of said, tube, said water being continuously introduced in such quantity as. continuously to maintain a film on said wall throughout a substantial portion of the length of the tube and to leave the center of the tube unobstructed, and discharging from the lower end of the tube the steam am. unevaporated water arriving at said end.

2. The method of generating steam, which consists in continuously forclng Water into the upper end of a heated tube having one end higher than the other and against the inner wall of said tube in such quantity and at such pressure in proportion to the heat of the tube as will continuously maintain a film on said wall substantially. throughout the length of the tube, while leaving the center of the tube unobstructed. and discharging the steam generated from said film and the unevaporated water from the lower end of said tube.

3. The method of generating steam, which consists in forcing water into the upper end of a heated tube having one end higher than the other and against theeinner walLotsaid tube in such quantity and at such pressure in proportionto the eat of the tube as will maintain a film on said wall substantially throughout the length of the tube, ,while leaving the center of the tube unobstructed, and dischar 'n the steam generated from said film an t e unevapor-ated wat r from the lower endof said tube and separating the steam from the water. 1

4. The method of generating steam, which consists in forcing water into the upper end of a heated tube having one endhigher than the other and against the inner wall of said tube in suchquantity and at such pressure in proportion tothe' heat of the tube as will maintain a film on the said wall substantially throughout the length of the tube, while leaving the center of the tube unobstructed, and discharging the steam generated from said film and the unevaporated water from the lower end of said tube, separating the steam, and returning the water end of the tube. i

5. The method of generating steam in a heated tube having one end higher than the other, which consists in continuously forcing water into the upper end of said tube 1n a quantity eater than will be evaporated in the tube i ut-less than suflicient to fill the tube and directin this water against the to the upper wall of the tube, t ereby leaving the center of the tube unobstructed to receive the steam generated from the formed upon the tube the steam and unevaporated .water from the lower end of said tube.

6.'The method of generating steam in a tube of relatively great .length in proportion film of water thus wall, anddischarging to its diameter and having one end hi her than the other and its lower end'open, w ich consists in heating said tube by heat-exchanging contact with heated gases traveling up the outside of said tube throughout substantially the whole length thereof, continuously forcing water into the upper end of said tube in quantity greater than will be evaporated in said tube but less than suflicient to fill the tube, directing this water against the inner wall thereof to form a film thereon, leaving the center of the tube unobstructed to receive the steam generated from said film, continuously discharging from the lower end of said tube the steam and unevaporated water reaching said end, and separating the steam, from the water.

7. The method of generating steam in a tube having one end higher than the other,

which consists in heating said tube by heatexchanging contact with heated gases traveling up the outside of said tube throughout substantially the whole length thereof, continuously forcing water into the upper end of said tube in quantity greater than will be evaporated in said tube but less than suflicient to filll the tube, directing this water against the inner wall thereof to form a film thereon, leaving the center 'of the tube unobstructed to receive the steam generated from said film, and continuously discharging steam and unevaporated water from the lower end of said tube,separating the steam from the water, and returning said water to the upper end of said tube. w I

8. In a steam generator a substantially direct generator tube sufficiently inclined to the horizontal to insure rapid gravity flow and having its lower end open, means for heating the tube, means for continuously forcing water into the upper end of said tube and so directing it a ainst the inner wall thereof as to form a lm thereon and leave the center of the tube unobstructed, and means for separating the water from the mixture of steam and water discharged from. the lower end of said tube. 9. In a steam generator a substantially direct generator tube sufliciently inclined to the horizontal to insure rapid gravity flow and having its lower end open, means for heating the tube, means for continuously forcing water into the'-upper end of said tube and so directing it against the inner wall thereof as to form a fihn thereon and leave the center of the tube unobstructed, means for separating the water from the mixture of. steam and Water discharged from the lower end of said tube. and means for conductin the separated water back to the upper end of said tube.

10. Apparatus for generating steam, comprising a series of substantiall generator tubes sufficiently incline to the horizontal to insure rapid gravity flow and.

direct v SllflIClGIlt to fill said tubes, means for so directing said water against the inner walls of said tubes as to form a film on said walls 'and leave the centers of the tubes unobstructed and means for separating the water from the steam and water collected in the collecting tube. v

11. Apparatus for generating steam, comprising a series of substantially direct generator tubes sufliciently inclined to the horizontal to insure rapid gravity flow and a distributing tube connected to the upper ends of said tubes, a collecting tube connected to the lower ends thereof, means for directing heated gases into. heat-exchanging contact with said generator tubes throughout substantially the whole length thereof, means for forcin water under pressure through said distri uting tube into the upper ends of said generator tubes in quantity greater than will be evaporated to the horizontal to insure rapid gravity flow and a distributin tube connected with the upper ends of sa1d tubes, 2. collecting tube connected to the lower ends thereof,

means for directing heated gases into heatexchanging contact with said tubes from the lower to the upper ends thereof, means for forcin water under pressure through said distri uting'tube into the upper ends of the generator tubes in quantity greater than will be evaporated in the respective tubesbut less than sui'ficient to fill them, means'for so directin said water against the inner walls of sai tubes as to form a film on said walls and leave the centers of the tubes unobstructed and means for separating the water from the steam and water collected in the collecting tube.

13. In a steam generator, a distributing thereof,

pared with its diameter sufliciently inclined tube, a series of generator tubes communicating therewith and having their ends fastened therein; and a second removable tube .within said distributing tube and provided with discharge orifices registering with the ends of said generator tubes which communicate with said distributing tube.

14. In a steam generator, a complete circuit for the water therein including a generating element through which the water gravitates, and a connection between the ends of said element through which the unvaporized Water is returned to the upper end thereof, means in said return connectlon for eflectlng the movement of the Water therethrough, and means also in said return connection for separating the steam from the mixture of steam and water issuing from the lower end of said generating element.

In testimony whereof I aflix my signature this 26th day of December 1918.

WALTER DOUGLAS LA MONT.

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