US2108072A - Steam generator - Google Patents

Description

Feb. 15, 1938. c. E. LucKE 2,108,072

STEAM GENERATOR original Filed Feb. 27, 1931 2 sheets-sheet 1 STEAM OUTLET INVENTOR Cha/ries E Lwclce -WY 855512. m

HIS ATTORNEY Feb. 15, 1938. c. E. LUCKE 2,108,072

STEAM GENERATOR Original Filed Feb. 27, 1931 2 Sheets-Sheet 2 INVENTOR C/mZeSE Lacke EER H l5 ATTORN EY Parel-ad ret. isyieee UNITED STATES PATENT OFFICEv STEM GENERATOR Application February 27, 1931, Serial No. 518,623 Renewed July 1, 1936 4 Claims. (ci. 122-235) This invention is a drumless steam generator of the once through type having several successive heat transfer sections through which the iluid, as it is being converted into vapor, at high pressure and temperature, progresses in sequence from entrance to outlet 'with no recirculation, the

vapor emerging as superheated steam.

With boilers of the aforesaid type, difficulty has been experienced in delivering steam of I proper superheat, due to the fact that e location at which steam generation ceases a d superheating =begins may vary; and then too, the different sections of the steam generator may have divergent heat transfer characteristics with the l result that the mixture of steam from the several sections may have an indefinite, diffrent, or changing quality, seriously interfering .with the proper utilization of the same in turbines and the like, unless a corrective or equalizing superheat is 2n imparted to the mixture at a predetermined location safe from overheating, which feature constitutes an object of the present invention. The zones where evaporation has been completed must be protected against overheating even if .33 they vary in position during operation.

Also,ythe arrangement of the several sections constituting the once through flow of entering cold water and emerging superheated steam, lin connection with the travel of the gases of combustion from which the heat is taken, represents another phase which forms an object ofthis invention. l.

And, furthermore, the provision of a furnace having a continuously progressive" gas passage Y 3f, from heat source to gas exit arranged inoloops,

with heat transfer sections disposed in and about the gas passage, and cold water entering the generatorin that section disposed in the cooler end of the gas passage and traversing successively convection, radiant and convection heat transfer surfaces until converted into superheated steam, constitutes another object of the invenf eicient power plants, and it is especially well adapted to the very largecapacities required by Fig. 1.

'I'he generator illustrated in the drawings as embodying the invention comprises a furnace l5 .formed of the enclosing bottom I,'top 2 and side wallsv, 4, 5 and 6, with an upright partition 'l which ends below` the top 2 leaving a horizontall gas passage 3 connecting the two vertical gas passages 9 and IIl for upflow-and do'wnflow of 2@ gases, respectively delivered from the combustion area in which are located fuel burners II. The back wall stops short of the bottom I whereby there is provided a horizontal gas passageY I2 leading to the flue I3 in which there may be 25 disposed an air heater Il, the gases of combustion passing upwardly therethrough andout at I5 while the air enters at I6 and is turned by the baiiles I1 to pass downwardly countercurrent to the gases of combustion past the guiding vanes I8 and out at I9 heated to the proper degree for use in promoting combustion.

The generator tubes are arranged inl sections in the order hereinafter described, the water entering the economizer section 20 as indicated at 35 2| being fed by means of the usual feed pump, not shown.

The economizer section 20 is located in the cooler end of the downwardly extending gas passage l0 and is comprised of a group of parallel vertically arranged' series coils of the/` serpentine or return bend type, yeach lindicated at 22 and originating in the header 23 connected with the water feed inlet 2| and terminating in the inggtothe upper header 26 of the slag and superheater screen 2l.

The slag s creen 2l, which also screens the superheater so that it is protected against overheating byl radiant heat, as shown, is disposed in the upwardly extending gas passage 9, and the water connection from the economizer 20 is connected as 'stated by the pipe 25 to the upper header 26 thereof so that the circulation of watezzas will be hereinafter noted,`i's countercurrent to the gas iiow in both the economizer and the slag screen. The slag screen 21, like the economizer 20, also comprises a plurality of parallel vertically arranged series coils of the serpentine or return bend type issuing from the upper header 26 and entering the lower header 28 from which the pipe 29 leads the water or mixture of steam and water to the radiantly heated section 30.

The section 30 in the radiant heat zone is a group of parallel tubes extending between entering header 3| connected with the pipe 29 and the outlet header 32, the tubes 30 being located in close proximity to the under surface of the top or roof wall 2 and covering the area at the turning point of the gases or the horizontally extending passage 8 connecting the upwardly and downwardly extending gas passages 9 and I0, respectively, and the steam and water from this primary or radiantly heated section 3|) passes from the header-32 to the vertical header 33 of the back Wall section 34, the headers 32 and 33 being connected together as at 35.

The back Wall tube section 34 comprises the receiving header 33 and the exit header 33 connected together by a group of parallel tubes forming the section 34 and lying close to the wall as is the case with the tubes 30. The water or steam and water mixture issues from the exit header 33 through the pipe 35' which is branched as at 31, 38, 39 and 40 to` feed the radiantly heated side wall sections disposed in the manner to be presently described.

The radiantly heated side wall sections are four in number and comprise groups of parallel tubes, vertically extending, and lying closely proximate their respective walls of the furnace. rIhe wall tube section 4| lies adjacent the front wall 3 and includes the lower header 42 and the upper header 43 connected by the saldi` tubes 4|, the lower header 42 receiving water or steam and water from the preceding sections through the branch 31 from the pipe 35 by means of the short branch 40, the steam and water traveling upwardly through the tubes '4| to' the header 43,V and the water decreasing progressively; the wall tube section 44 lies adjacent the back wall 1 and includes the lower header 45 and the' upper header 46 connected by the wall tubes 44, and this wall section is distinguished from the other in that, at its upper portion it crosses the horizontal gas passage 8 and therefore some provision must be incorporated for affording adequate transmission of the gases of combustion through the tube screen formed thereby, consequently, the upper portions of these tubes 44, where they cross the horizontal gas passage 8, are alternately bent or offset as shown at 41 and 48 to facilitate the passage of gases of combustion therebetween without'too much resistance. The wall tube section 44 receives its supply of water or steam and water from'the pipe 35 through the branch 38 leading to the lower header 45 so that, like wall tube section 4|, the passage of steam and water is upwardly through the wall tube section,

and the water decreases progressively as steam generation occurs. The remaining wall tube sec` tions are side wall tube sections 49, the tubes of which are bent aside to permit the entrance of burners Il, as shown, and which tubes connect lower header 50 and upper header 5|, water or steam and water entering the lower header 50 through the connection 39, and the remaining side wall tube section being indicated at 52, the tubes of which connect lower and upper headers 53 and 54 respectively, with steam and water entering the lower header 53 through the connection 54.

It will be apparent, from the foregoing description, that all the side wall sections are comprised of parallel tubes divided into groups and with water or steam and water owing in at the bottom headers and steam outat the top headers, which latter is assured by the proportions of the several sections of the heating surface one to'another, and to Athe size of furnace or heat developed therein.

AV convection superheater 55 is disposed in the entrance to the downiiow gas passage l0 in advance of the econornizer 20 and comprises a lower y header 56 and an upper header 51 connected by parallel vertically arranged serpentine or return bend type tubes. This is wholly screened from radiant heat from the furnace by the screen 21 and by the roof and side wall tubes of the upper chamber over and in advance of the superheater.

Steam leaving the radiantly heated side wall tube sections 4|, 44, 49 and 52 through their respective upper headers is accumulated and joined by the connections 58, 59, 60, 5|, 62 and 63 so that it enters the pipe 64 leading to the lower header 56 where the steam, which is mixed in transit through the pipe 64 and in the header 56 may have, through such mixing, some superheat even though the degree of superheat of the steam from the several sections might be diil'erent until joined, and in this convection superheater there is imparted to the accumulated steam a final temperature or superheat whereby the steam leaving the convection superheater 55 through the steam outlet 65 has a definite superheat value as required by the turbine.

While inthe foregoing I have described a specific arrangement of steam generator of the dru'mless type, it is nevertheless to be understood that the positions of the boiler components comprising the generating surface may be altered With respect to each other, or with respect to the gas passage, without departing from the spirit of the invention as defined in the appended claims.

I claim:

1. In combination, a forced flow vapor generator including a furnace receiving and radiantly burning elements of combustion, a gas passage having a gas turning zonel connecting the samewith said furnace, a fluid passage comprising groups of tubes with the tubes of each group in parallel and one of said groups having parallel lengths disposed along the walls of the furnace, said groups successively connected for serial progression oi? the fluid therethrough from liquid entrance to vapor outlet, one of saidgroupsA being located transversely` of thefurnace wall tubes in advance of the gas turning zone and across the path of the gases to form a ra,-

diant\ heat shield for another of said groups across the gas passage beyond the gas turning zone, the said last two mentioned groups beingin parallel and one of said groups having parallel lengths disposed along the walls of the furnace, said groups successively connected for serial progression of the uid therethrough from liquid entrance to vapor outlet, one of said groups being located transversely of the furnace wall tubes in advance of the gas turning zone and across the path of the gases to form a radiant heat shield for another of said groups across the gas passage beyond the gas turning zone, the said last two mentioned groups being spaced marginal to the turning zone to provide therein an unoccupied chamber whereby the gases passing through the first of the last two mentioned groups are enabled to become evenly distributed throughout the area of the succeeding group crossing the gas passage, some of the aforesaid groups providing a cooling tube surface for the sides of the said unoccupied chamber.

3. A forced ow vapor generator comprising walls forming a furnace and adjacent gas flues in parallel relation, means radiantly iring the furnace, a continuous uid flow conduit receiving liquid at the cooler end and delivering superheated vapor at the other end, said conduit including sinuous portions horizontally arranged across the ilues and connected for fluid flow always countercurrent to gas ow while the fluid moves progressively from a cooler portion in one ue to a hotter portion nearer the furnace outlet and some of which are heated by convection, tubes longitudinally of the walls in the radiant heat area, and a superheater intermediate the convection portions and arranged for fluid flow transverse to the gases passing the same while connected for fluid iow countercurrent to the gases, the said longitudinally disposed tubes and the superheater being a part of the aforesaid continuous fluid flow conduit.

4. In combination, a forced flow vapor generator including a furnace receiving and radiantly burning elements of combustion, a gas passage having a 180 gas turning zone connecting the same with said furnace, a fluid passage comprising groups of tubes with the tubes of each group in parallel and one of said groups having parallel lengths disposed along the walls of the furnace, said groups lsuccessively connected for serial progression of the iiuid therethrough from liquid entrance to vapor outlet, one of said groups being located transversely ofi. the furnace wall tubes in advance of the gas turning zone and across the path of the gases to form a radiant heat shield for another of said groups across the gas passage beyond thel gas turning zone, the said last two mentioned groups being spaced marginal to the turning zone to provide therein an unoccupied chamber whereby the gases passing through the first of the last two mentioned groups are enabled to become evenly distributed throughout thel area of the succeeding group crossing the gas passage, another of said groups being located beyond the last mentioned groups and connected for uid iow countercurrent to the direction of passage of the gases thereover and thence connected to the irst of the aforementioned groups.

CHARLES E. LUCE.y

Images