US2009404A - Steam generation - Google Patents

Description

July 30, 1935 V 'w. D. LA MONT I STEAM GENERATION Original Filed Jan. .23, 1926 T R 0M MA R N w u 0 D H m m w WBYA W oRNEYS.

Patented July 30, 1935 UNITED STATES PATENT OFFICE I 2.001%404 )STEAM GENERATION Original app ication January. 23, 1926, Serial No. 83,235. Divided and this application April 19,

1929, Serial 20, 1934 No. 356,406. Renewed December 18 Claims. (c1. 125-3 This invention relates to a specific arrangement of steam generating elements and superheating elements and is a division of my application Serial No. 83,235, filed January 23, 1 926, for

5 Steam generation.

In said prior application I have shown and claimed an arrangement for controlling the superheat of steam wherein thefiow of steam through the superheater elements is subjected to the same progressive. change of temperature corresponding to that to which the steam generating elements themselves are subjected. In said application there is also described and claimed the control of the temperature of the superheated steam by varying the amount of steam passing through different elements of the superheater.

The present application relates to a specific arrangement of steam generating and superheater elements embodying the broad principles of the parent case but directed more particularly to a construction whereby the velocity of the heating gases throughout its passage over the steam generating elements and superheater elements is maintained. The invention is illustrated in the accompanying drawing in which 7 Figure 1 shows a section through the generator.

Figure 2 shows water restricting means at the inlet ends of the tubes.

The generator consists in an integral lower header or pot 282 and three separate upper headers 283, 284 and 285 connected to the pot by the tubes 286, 281'and 288. The three sets of tubes are separated by the two baflles 289 and 299 and thus form three passes. The gas flow as'shown by the arrows is upward through the, first pass,

downward through the second and upward through the third. The baflles are so inclined and the spacing of the tube connections on the headers is so proportioned that the cross-section of each pass decreases continuously in proportion to shrinkage in volume of the combustion gases as they are cooled in passing over the tubes. The

first and third passes are provided with water injection into the headers 283 and 285 by means.

of the pump 29!, pipe 292 and branch pipes 293 and 294 provided with the valves 295 and' 298. The feed water is added to the pump circulation through the pipe 291 provided with the valve 298 which is actuated by the water level control '299.

superheated steam is taken off from the headers 284 through the pipe 380.

The operation of the generator is asfollows: For normal low ratings the valves 295 and 296 are so adjusted that the amount of water intro-- duced into the tubes 286 is greater than that which danger of burning out. The generating tubes 288 burning out. Where, however, in-

can be evaporated by passing therethrough and accordingly saturated steam and water is discharged in the lower portion of the pot 282. The

amount of water introduced to the header 285, however, is less than that which can be evapo- 5. rated in the tubes 288 and accordingly superheated steam is discharged from these tubes into the upper portion 'of the pot. The saturatedsteam from the tubes 28B and moderately superheated steam from the tubes 288 then flows up through the tubes 28'! where it is further s'uper-' heated. Asthe boiler rating increases, a larger and larger quantity of water is introduced into the header 285 so that the steam discharged from :the tubes 288 is of a lower and lower superheat 16 temperature and finally is discharged in the form of saturated steam. i

It will be seen that the hottest gases in the first pass come in contact with tubes which are suppliedwith an ample amount of water and are not subject to danger from irregular running 01' the .boiler or sudden increase in flame temperature. The superheater tubes 28'! are in the zone of sufliciently low heat so that they are not in 25 situated in the lowest heat zone, subsequently abstract from the cooled gases their last quota of heat so that the gases passing out to the stack may be in ordinary operation at or near the temperature of the water introduced into the header 285. p

Where the flame is not extreme in temperature or where the pot and generating tubes 286. are made of particularly resistant metals, it is possible to generate superheated steam in the tubes 286 as well as in the tubes 288 by restricting the water fiow through the valve 295. This makes possible a very high superheat since the superheater tubes 28! are not fed with saturated steambut are fed witnsteam which is already superheated. J

Manually operated valves 295 and 296 have been shown, but it is oi course obvious that a thermostat can be placed in the superheated steam pipe, 308 andvuse'd to automatically operate the valve 296 in order to control the superheat by control of the temperature of the steam generated in the tubes 288. For most purposes it is desirable to use manual control on the valve 295 or if an automatic control is desired this is preferably actuated by the water level 299 as it is important in most installations to assure a continuous and plentiful supply of water to the tubes inv the first pass to prevent their stallations it is desired to generate superheated steam in the tubes 286, the valve 295 can, of course, also be controlled thermostatically in accordance with the temperature of the superheated steam in the pipe 300. Other methods of control may also be used and are included in the invention.

Also, as described in my application Serial No. 83,235 above referred to, the steam generating tubes may be provided with means at their water inlet ends for restricting the flow of water delivered to the tubes. As described in my Patent No. 1,545,668 dated July 14, 1925, this flow may be in amount less than sufficient to fill the tube while providing an amount greater than the evaporation within the tube.

In Figure 2 of the drawing is shown a section of a header 305 which may be, for example, one

of the transverse headers to which tubes 286 are connected at their upper ends and which is connected to the header 283. Within the header 305 may be fitted an orifice tube 306 having openings or orifices therein registering with the upper ends of the tubes 286. The water entering the orifice may thus be distributed to and injected into each of the tubes 286 through the orifices 301, said orifices providing means for restricting the fiow in the manner referred to above and as disclosed in said application and patent.

The design and shape and the number of passes may be varied greatly depending on operating conditions and on the space available. It is thus perfectly practicable to use a double pass omitting the tubes 288. A saving in space is effected at the expense of reliability of superheat control and also at.the expense of efliciency as it is relatively difiicult with a practical number of tubes to reduce the gas temperature in .the superheater pass to the temperature of the saturated steam entering it, whereas it is a very simple matter to reduce the gas temperature to or near that of the intake water when the last pass contains generating tubes owing to the very high heat absorption of the water film in the tubes. It should be understood, however, that the principles of the invention are in no sense limitedto the three-pass generator shown, which, however,

constitutes the preferred embodiment of my invention and, as pointed out above, combines a maximum of efiiciency and reliability of temperature control with compact arrangement and reasonable draft pressure.

The header, tube and pot construction of the three-pass generator and superheater described above may, of course, be greatly varied within the scope of the present invention. The drawing is purely diagrammatic and is not intended to show structural details with which, in its broader aspects, the present invention is not concerned. The separate top header construction, shown for the sake of simplicity, is efficient and practicable, but many other modifications may be utilized.

What isclaimed as new is: 1. An apparatus for generating superheated steam comprising a plurality of tubes, a common header to which one end of each of the tubes is connected, means for so positively delivering water to the tubes to be used for steam generation at the ends thereof remote from the header and causing the same to flow unidirectionally therethrough that the steam generated therein is discharged into the header, and means for withdrawing from the other tubes connected to the header at the ends thereof remote from the headthe header, and means for discharging from the ends of the superheating tubes remote from the header the steam received therefrom by these tubes.

3. An apparatus for generating superheated steam comprising steam generating tubes all extending in the same general direction, superheating tubes extending in the same general direction as the steam generating tubes, a common header to which one end of each of the tubes is connected, means for delivering water to the ends of the steam generating tubes remote from the header, so as to cause the steam generated to discharge into the header, means for discharging from the ends of the superheating tubes remote from the header the steam received therefrom by these tubes, and means for causing heating gases to pass in counterfiow relation to the how of steam through the tubes.

4. An apparatus for generating superheated steam comprising tubes to one end of which the water for steam generation is delivered, other tubes from one end of which the steam after being superheated therein is discharged, a chamber connected to the remaining ends of all the tubes for separating from the steam any water contained therein before it becomes superheated, and means for returning the water to the input ends of the tubes for steam generation and for positively causing flow of the water through said tubes toward said chamber.

5. An apparatus for generating superheated steam comprising two spaced sets of steam generating tubes all extending in the same general direction, a set of superheating tubes located therebetween and extending in the same general direction as the steam generating tubes, a common header to which one end of each of the tubes of all the sets is connected, means for positively delivering water to that end of each of the steam generating tubes remote from the header and discharging the steam generated into the header, and means for withdrawing from the ends of the superheating tubes remote from the header the steam flowing through these tubes from the header.

6. An apparatus for generating superheated steam comprising a plurality of sets of tubes arranged adjacent to each other and all extending in the same general direction, walls enveloping said tubes to form a chamber for confining heating gases, a partition wall between adjacent sets of the tubes and extending in the same general direction as the tubes to form adiacent passages through which the heating gases flow successively in intimate contact with the sets, a single header connected to all the tubes at one end of each set, means for so positively delivering water to some of the sets of tubes at the ends thereof remote from the header that the steam generated therein is discharged into the header, and means for withdrawing from the iiow successively and in intimate contact with other sets of tubes connected to the header at the ends thereof remote from the header the steam received by said tubes from the header.

7. {in apparatus for generating superheated steam comprising walls forming a chamber for confining heating gases, partitions mounted within said chamber in suchrelation to each other and to the walls as to form a continuous sinuouspassage, steam generating and superheating tubes extending in said passage lengthwise thereof, means for positively delivering the water for steam generation to each of the steam generating tubes adjacent one end of a portion of the passage so as to cause the generated steam to be discharged adjacent the other end of a portion of the passage, means for delivering the steam to be superheated to the superheater tubes adjacent one end of a portion of the passage, means for discharging steam from the opposite ends of the superheater tubes, and means for causing the gases to flow through the passage from one end thereof to the other.

8. An apparatus for generating superheated steam comprising walls forming a chamber for confining heating gases, partitions 'mounted within said chamber and converging in relation to each other and the walls so as to form a continuous sinuous passage of progressively reducing cross sectional area in one direction of its length, tubes extending in said passage lengthwise thereof and more closely spaced adjacent their ends which lie in the portion of thepassage having less cross sectional area relative to the portion adjacent their other ends, means for delivering water to-some of the tubes and the steam to be qsuperheated to other tubes at the ends thereof which respectively lie adjacent the portions of the a passage of less cross sectional area, and means for causing the gases to flow through the passage toward the end thereof having smaller cross sectional area. a

9. An apparatus for the generation of superheated steam comprising steam generating tubes and adjaeently arranged superheating tubes extending in the same general direction as the steam generating tubes, walls enclosing the tubes and forming a chamber for confining the 'hot gases introduced therein, partition walls in said chamber placed between certain of the tubes and converging in such relation to each other and to the walls of the chamber as to form passages adjacent to each other through which the gases flow successively and in intimate contact with the tubes, said passages havinga cross sectional area which reduces in the direction of the gas flow, a

common header located adjacent one end of bothsteam generating and superheating tubes into which header the steam generating-tubes discharge the steam generated therein an from which at the same end the superheating elements receive the steam to be superheated, and means for positively delivering water to that end of all the steam generating tubes which is remote from the header.

10. An apparatus for the generation of superheated steam comprising steam generating tubes and adjacently arranged'suprheating tubes exthe tubes, said passages having a cross sectional area which reduces in the direction .of the gas -fldW,'8.' common header located adjacent one end of both steam generating and superheating tubes into which header the steam generating tubes discharge the steam generated therein and from which at the same end the superheating elements receive the steam to be superheated, and means for positively delivering water to that end of all the steam generating tubes which is remote from the header, said header being so located in relation to the flow of gas over the superheater tubes that the flow of steam in the superheater tubes is in counter direction to the gas flow.

11. An apparatus for generating steam, comprising a plurality of tubes arranged adjacent to eachother and extending in the same general direction, wallsv enveloping said tubes to form passages for confining heating gases in intimate heat exchanging contact with the tubes, a header atone end of the tubes to which all the tubes are connected in common, a plurality of manifolds at the other. end of the tubes to which the tubes are connected in sets, means for delivering the water for steam generation to some of the manifolds and causing it to flow positively through the tubes of their sets toward the header, and means for discharging the steam received by the manifolds of other sets of tubes, whereby these tubes are used as superheater tubes, the

passages being so connected that the flow of gases is counter to the flow of steam in the superheater tubes.

12. An apparatus for generating superheated steam comprising a plurality of closely spaced tubes of small diameter and all of the same length and all extending inthe same general direction, walls closely enveloping said tubes to form a chamber for confining heating gases in intimate heat exchanging contact with the tubes, parti-- steam generating tubes and the adjacent ends of the superheating tubes are connected in which the steam and water discharged from the steam generating tubes are separated, a connection from said header to said pump whereby the excess water is returned to said water manifolds, a steam manifold adjacent the larger end of the portion of the passage in which the superheating tubes lie to which are connected the ends of these tubes remote from the header so as to collect and discharge the steam flowing from said header through said tubes, and means for causing the heating gases to flow through the passages in counterflow relation to the flow of water and steam in the tubes.

13. Apparatus for generating superheated steam comprising steam generating tubes, means for-so positively delivering water to one end of each of said tubes as to cause it, together with the generated steam, to flow through the tubes toward the other end thereof while preventing return flow of the water through said tubes, a chamber connected to said other ends of the tubes thereof to said chamber, and means for withdrawing from the other ends of said superheater tubes the steam received from said chamber.

14. Apparatus for generating superheated steam comprising a plurality of tubes, a header to which allthe tubes at one end thereof are connected, means for causing water positively to flow through certain of the tubes used as steam generating tubes toward the header while preventing return flow of, the water through said tubes, and means for withdrawing superheated steam from the ends of other tubes remote from the header.

15. Apparatus for generating superheated steam comprising a plurality of tubes, a header to which the tubes at one end thereof are connected, means for positively delivering to certain of the tubes at the ends thereof'remote from the header water in quantity in excess of the steam generated in said tubes but in quantity less than sufficient 'to fill the cross sectional area thereof, said header serving to separate the excess water from the steam discharged thereinto, and means for withdrawing from others of the tubes connected to the header at the ends thereof remote from the header the separated steam superheating tubes each having its inlet end at a point in the passage at a. distance from its respective outlet end, means for positively delivering water to the steamgenerati'ng tubes at the inlet ends thereof and discharging steam at the outlet ends thereof, means for delivering steam .to the inlet ends of the superheated tubes and discharging the superheated steam from the outlet ends of said'superheater tubes, and means for causing the gases to flow through the passage in counter flow relation to the flow of steam in the superheater tubes.

17. An apparatus for generating superheated steam, comprising at least two tubes, a common headerto which one end of each of the tubes is connected, means for delivering water to one of the tubes to be used for steam generation at the end thereof remote from the header, means associated with said tube for insuring unidirectional flow of the water through said tube toward the header together with the steam generated therein, and means for withdrawing from the other tube at theend thereof remote from the header the steam received from the header and superheated in said other tube. I

18. An apparatus for generating'superheated steam, comprising a plurality of tubes, a common header to which one end of each of the tubes is connected, means for withdrawing from some of the tubes at the ends thereof remote from the header steam received from said header by said tubes and superheated therein, means fordelivering water to the remaining tubes at the ends thereof remote from the header, and means at said ends of said remaining'tubes for insuring the distribution of the water to each tube and its flow therethrough toward the header.

WALTER'DOUGLAS LA MONT.

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