US1858872A - Combined superheater and boiler - Google Patents

Description

" y 17, 1932; w. H. ARMACQST 5 counnwn SUPERHEATER AND Burma Filed Jan. 21. 19:50 2 Sheets-Sheet 1 6. INVENTOR- Wl/fiur fi/macad'f a .Z

' ATI'ORN EY Filed Jan. 21, 1930 2 Sheets-Sheet 2 ooooooQ INVENTOR M/fiur flf/rmaumf a? Que ATTORNEY wrmmn n. ARMACOST, or

Patented May 17, 1932 NEW xonx, n.

Y., assIen'oa 'ro 'rnn surnam'rna courm,or NEW YORK, m

commnn surnnnnarrm Ann 301mm Application fll edl'anuary 21, 1930. Serial No. 422,329.

My invention-relates to the art of-steam production and aims to provide an efficient arrangement .of superheater and bo1ler adapted for economical manufacture, mstallation and operation.

In sup lylng superheated steam to prlme movers fiom combined superheaters and boilers having common furnaces, difliculty has been experienced in maintaining the temperature variations of the superheated steam within desired limits at different rates ofv firing.

It is an object of my invention to provlde a combined superheater and boiler adaptedto avoid such difliculty.

In accordance with the aims above stated,

a superheater boiler installation within my invention may comprise a superheateryboiler and furnace having the superheater elements arranged in two groups, one of which is so ositioned with respect to the furnace and oiler that it receives a considerable portion of its heat by radiation from the furnace and the other group of elements arrangedso that it receives the most of its heat from the combustion gases from the furnace and so that the percentage of surface area of the second group of superheater elements in the stream of combustion gases from the furnace increases with an increase'in rate of firing of the furnace. Furthermore, the boiler'is preferably connected to the two groups of superheater elements so that the saturated steam flows from the boiler into the group subjected to thegreater amount of radiation and then into the group of elements receiving its heat primarily from the furnace gases, the two groups being in series in the path of the steam flow. It is a feature of my invention also to so arrange the group of superheater elements receiving the greater amount of radiation that the percentage of its surface area lying in the stream of combustion gases changes very little with ordinary changes in rate of firing of the furnace. In

practical installations, it has been found desirable to place the convection group of. superheater elements outside of the steam generating tubes and the radiant group of superhea-ter elements intermediate the bank of generating tubes nearest the fire. The novel features of my invention are pointed out with particularity in the appended claims. The invention, however, to-

gether with further objects and advantages, will best be understood from a scription of an illustrative arrangement of a combined superheater, boiler and furnace embodying the invention andsuch a descri tion will now be given in connection with t e accompanying drawings in which a Fig.1 is a sectional elevation through a cross drum boiler having semi-vertical tubes combined with a superheaterfand furnace in accordance with my inventiontFig. 2 is an enlarged section on the line'22 of Fig. 1

- looking in the direction of the arrows.

Referring to the drawings more in'detail, the illustrative embodiment of my invention therein shown comprises a boiler having upper drums 10,12, connected by water tubes to' a lower drum 14, said tubes comprising a front bank 16 and rear banks 18 and 19. The front wall of the boiler settin is shown at 20 and below the drum 14 and tubes 16 is a furnace chamber 22. The bank of tubes 16 is shown in semi-vertical. position and as inclined forwardly from the vertical to some extent in passing from the lower drum 14 to the upper drum 10, so that the upper end of bank 16 lies nearer the front wall 20 than the lower end and the upper drumlO is in front of lower drum 14. A bafile 24 is shown at the rear of bank 16 running parallel to the tubes of such bank and arranged to direct the combustion gases from furnace 22, in

lar e measure, longitudinally of the tubes in suc bank.

I In addition to the bank of tubes 16, drums 10 and 14 are shown as connected by a set of tubes 26 lying in front of the bank 16. At their point of exit from drum 14, tubes 26 are shown as running almost horizontally, but a short distance from drum 14 such tubes incline upwardly somewhat from the horizontal and extend forward nearly to the front wall 20. Near the front wall, tubes 26 curve upwardly and then re-curve toward the bank 16, running from near the front wall somedetailed d'ee what upwardly to a point 28 near the bank 16 and thence extending upwardly to the drum 10 parallel to such bank so as to leave a space 29 between their upper portions and wall 20.

The elements of the superheater are shown as divided into two groups, one of which is designated as 30 and lies within the space outlined by the tube bank 16 and the upper portions of tubes "26. Elements in group 30 run parallel to the tubes of bank 16 and are fastened to tubes of bank 16 and additional tubes 26 by straps 31, 31. Elements of group 30 extend downwardly toward the furnace 22 so as to receive considerable heat by direct radiation from the furnace.v Furthermore, elements of roup 30 are so interspersed in the tubes of bank 16, and the bank 16 and baffle 24am so arranged that the major portion of the surface area ofthe elements of group 30 lies intbe stream of combustion gases from furnace 22 even at low firin rates of the furnace, whereby the total 0 heat units imparted to the steam by the elements of group 30 changesvery little with ordinary changes in the rate of firing. A suitable arrangement of tubes 16 and 30 for such purposes is illustrated in detailin Fig. 2. As shown, the tubes in bank 16 and the additional tubes 26 are 3 outside diameter and are spaced 6% between centres both in the direction parallelto baffle 24 and in the direction at-right angles to it.. Tubes in group 30 may be either of 1%" or 1 inside diameterwhen used with tubes 16 of the size and arrangement above stated and are arranged preferablyparallel to tubes 16 in rows running at right angles to bafile24 and spaced somewhat closer together within bank 16 than in the space between bank 16 and tubes 26 and between tubes 26. Each row of tubes 30 preferably contains four tubes in the space within tube bank 16 and two tubes outside such bank,one between bank 16 and tubes 26 and one within the space outlined by tubes 26. g I

A second group 32 of superheater elements is shown in the space 29 intermediate the upper ends of the additional tubes 26 and the front wall 20. Elements of group 32 are held together by transverse braces 34, 34, and the lower end of the-front elements of such group are supported on an angle 35 fixed to the recurved portion'of the water tubes 26 while the upper ends of the front elements of such group rest on angle 37 fixed to the front wall 20. It will be seen that the elements of group 32 are so placed that only a minor portion of their surface area lies inthe stream of combustion gases from furnace 22 at low firing rates of the furnace but that, as the rate of firing of the furnace is increased, the stream ofgases is thereby widened to increase the portion of the area of such elements in amount of contact with the gases of combusthe relativefliy large amount of shielding from radiation :1 orded them by the re-curved por: tions-of the additional tubes 26.

The groups of elements 30 and 32 are connected in series in the path of the steam flow and, in accordance with my invention, the group 30 receives the saturated steam direct from the boiler, thereby protecting group 30.

against overheating. For this purpose, saturated steam is conducted from the rear drum 13 of the boiler through a steam pipe 36 to a header 38 to which the elements of grou 30 are connected by the steam leads 40. The other ends of the elements of group 30 are connected to a second header 42 by steam loads 44. From header 42 steam may be conducted to the superheater elements 32 by steam leads 46, the other ends of elements in group 32 being connected to a third header 48 by means of steam leads 50. From header 48 the steam may be conducted to the prime mover, or other steam consuming apparatus by means of a pipe 52. I

If desired, additional water heating sur- I face maybe supplied by means of to es 54 7 below the combustion zone and connected between a rear header 56 and a front header or drum 58, steam from drum 58 passing into drum 10 through pipe 60.

A steam generating apparatus, designed and operating on the principles above de-,;

scribed is capable of supplying large quantities of steam at a high degree of Sn erheat but with relatively slight variations 0 super.- heat with changes in boiler rating. Moreover, the super-heater elements have a comparatively long life. i

I claim: v

1. The combination of a furnace, a boiler heated thereby, two groups of superheater elements, one of which is arranged to receive a relatively large amount of radiant heat from said furnace as compared to the other, said other group of superheater elements so arranged with respect to said boiler and furnace that the percentage of its surface in the stream of combustion gases from the furnace increases automatically with increase in rate of operation of the furnace, and connections leading steam from the boiler first through said radiant group of elements and then surface within the gas stream at low rates of firing, said other group of superheater ele niatically with increase in rate of operation of the furnace, and connections leading steam from the boiler directly to said radiant group and there to said other group of superheater elements.

3. The combination with a furnace, of a boiler having an inclined bank of water tubes arranged to receive radiant heat from said furnace at one end, a bafiie arranged to direct the combustion gases along said tubes, a group of superheater elements extending parallel to said tubes into the zone of radiant heat and so interspersed among said water tubes as to restrict the volume of gases flowing through the space outlined by the tube bank and elements to prevent material variations in the amount of heat absorbed by such group with variations in rate of steam generation, a second group of superheater elements relatively sheltered from radiation and so arranged that the combustion gases from said furnace 'flow automatically over a greater ercentage of its'area with increasing rates of combustion, and connections for leading steam from said boiler through the elements of said groups.

4. The combination of a boiler comprising an upper drum, a lower drum, and a front bank of semi-vertical water tubes connecting said drums, a bafiie extending upwardly from said lower drum along the rear of said bank, additional water tubes connecting said drums and extending forwardly from said lower drum, and then recurving toward said bank, a group of superheater elementsinterspersed in the tubes of said bank and running parallel therewith, a second group of superheater elements lying above the recurved portion of said additional tubes, and steam connections between said boiler and groups of elements.

5. A boiler as set forthin claim 4 together with means leading saturated steam directly from the boiler to the interspersed group of elements and from the interspersed group to the second roup of elements.

6. The com ination of a boiler having a lower drum, an upper drum in front of said lower one and a. front group of water tubes connecting said drums, a group of superheater elements interspersed in said tubes, a second group of superheater elements in front of said tubes, and steam connections between said boiler and groups of elements.

7. The combination of a furnace, a boiler heated thereby and having a lower drum and an upper drum in front of said lower one, and water tubes connecting said drums, the front ones of said tubes running forwardly above the furnace and then recurvingtoward theothers, a group of superheater elements interspersed in said tubes, a second-group of superheater elements in front of the upper portions of said tubes and above the recurved portion of said front tubes, and steam connections between said boiler and groups'of elements. r

'8. The combination as set forth in claim 6 and in'which the steam connections lead the steam from the boiler directly to the group of superheater elements among the water tubes and then to the group in front of the'water tubes.

i 9. The combination assetforthin claim 7 and in which the steam connections lead the steam fromthe boiler directly to the group of superheater elements among the water tubes and then to the superheater elements in front of the water-tubes.

10. The combination as set forth in claim 6 and in which the water tubes are so ar ranged with respect to the elements interspersed therein that the amount of gases contacting with the inters ersed superheater elements varies relative y. little compared withvariations of boiler rating throughout the ordinary range of such variations.

11. The combination of a furnace, a boiler heated thereby, two groups of superheater elements both directly above said furnace, one of said groups being arranged to receive a relatively large amount of radiant heat from said furnace as com ared to the other,

said other group of super leater elements being so arranged with respect to said boiler and furnace that the percentage of its surface in the stream of combustion gases from the furnace increases automatically with increase in rate of operation of the furnace, and connections leading steam from the boiler first through said radiant group of elements and then throu h said other group.

12. The combination of a furnace, a boiler heated thereby and having an up-pass for gases from said furnace, two groups of superheater elements both in said up-pass, one of said groups being arranged to receive a rellarge amount of radiant heat from ativeiyI .said rnace as compared to the other, said other group of superheater elements so arranged with respect to said boiler and fur-' nace that the percentage of its surface in the stream of combustion gases from the furnace increases automatically with increase in rate of operation of the furnace,

and connections for leading steam from the boiler having an inclined bank of watert tubes arranged to receive radiant heat from said furnace at one end, a bafiie arranged to direct the combustion gases along said tubes,

6 a group of superheater elements extending parallel to said tubes into the zone of radiant heat and so interspersed among said water tubes. as to restrict the volume of gases flowing through the space outlined bythe tube.

10 bank and elements to prevent material vari- 1 atio ns in the amount of heat absorbed by such group with variations in rate of steam generation, a second oup of superheater elements arranged at su stantiallythe same distance from the-furnace as a portion of said first group,but relatively sheltered from radiation and so arrangedtha't the combustion gases from said iurna'ce flow automatically over a greater percentage of its area with in- 201'CIe8S1I1g rates of combustion, and-connections I I i the elements ofsai'dlgrou s.

, for leading steam from said boiler through R 'Aitmoosr

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