US2867416A

US2867416A - Tubular combustion chamber lining for forced flow steam generators

Info

Publication number: US2867416A
Application number: US440393A
Authority: US
Inventors: Lieberherr Arthur
Original assignee: Sulzer AG
Current assignee: Sulzer AG
Priority date: 1953-10-15
Filing date: 1954-06-30
Publication date: 1959-01-06
Anticipated expiration: 1976-01-06

Description

Jan. 6, 1959 A. LIEBERHERR 2,867,416

TUBULAR coususuou CHAMBER LINING FOR FORCED FLOW STEAM GENERATORS Filed June 30, 1954 WWW m in

v G J 6 Lfl a p 54 g 8! o a n m o v k a y :4 INVENTOR. \J I a I ART'HuEL/EBEEHERR.

/ ATTORNEK nited Slitgs TUBULAR COMBUSTION CHAMBER LINING FOR FORCED FLOW STEAM GENERATQRS Arthur Lieberherr, Winterthur, Switzerland, assignor to Sulzer Freres, Socit Anonyme, Winterthur, Switzerland, a corporation of Switzerland The present invention relates to a tubular combustion chamber lining for forced flow steam generators, particularly for steam generators operated at the critical or at super-critical pressure.

The lining according to the invention consists of adjacent parallel tubes whose ends are connected with tubular headersor collectors. Each collector receives the outlet ends of a group of tubes forming the combustion chamber wall and the inlet ends of a group of tubes through which the water or steam subsequently flows to another collector. The axially aligned headers or collectors form two parallel rows, the collectors of one row being axially staggered with respect to the headers of the other row, so that the groups of tubes through which the water or steam flows in series follow a zig-zag pattern. The individual tubes connecting two headers may be bent like hairpins. The hairpin'bends may be replaced by short individual and axially aligned headers.

Tubular evaporating or superheating heating surfaces forming, for example, the inner lining of the walls of the combustion chamber of a steam boiler, which heating surfaces are operated at subcritical pressures must be so constructed that there is no separation of the steam from the water and consequently no ununiform passage of operating medium through the individual parallel tube lines. In tube systems in which water is converted to steam at a pressure near or higher than the critical pressure undesirable separation of water from steam can be avoided if the-lines of heating tubes extend continuously through the steam generator without interruption by transverse connections or collectors. Such long tube lines must be bent to follow a meander-like pattern and there-are spaces between the individual return bends which are not covered by heating tubes and through which the flame or gas radiation may adversely affect and destroy the insulation or the brickwork in the back of the tubes. A further disadvantage is the formation of ash and slag deposits in the spaces between the bends. Brickwork for the combustion chamber walls cannot be dispensed with if the tube lines are constructed as explained above.

If the combustion chamber walls are lined by individual tube groups arranged in series, and if the ends of the tubes of each group are connected with inlet and outlet headers, unheated downcomer tubes must be provided which entail additional expense and considerably increase the weight of the plant without being useful as heating surfaces. The downcomer tubes which are useless for steam generation but which are capable of storing a relatively great volume of high pressure and high temperature operating medium constitute a considerable source of danger in case of tube explosions.

The aforesaid disadvantages can be avoided in a simple manner by constructing the combustion chamber walls or the interior lining thereof according to the invention.

The novel features which are considered characteristic of the invention are set forth with particularity in the atent ice appended claims. The invention itself however and additional objects and advantages thereof will best be understood from the following description of embodiments thereof when read in conjunction with the accompanying drawing, in which Fig. 1 is a diagrammatic illustration of a combustion chamber wall formed of groups of parallel tubes, only a few tubes being shown;

Fig. 2 is a diagrammatic illustration of a modified combustion chamber wall formed of tubes bent like hairpins, the parallel rows of collectors which are interconnected by the tubes being in close vicinity;

Fig. 3 is diagrammatic illustration of 'a modification of the combustion chamber wall construction shown in Fig. 2, in which the hairpin bends are replaced by short axially aligned headers;

Fig. 4 is a diagrammatic cross section through a combustion chamber wall according to Fig. 1;

Fig. 5 is a diagrammatic cross section through a combustion chamber wall according to Fig. 2;

Fig. 6 is a diagrammatic cross section through a combustion chamber wall according to Fig. 3.

The same numerals designate the same parts in all figures.

Referring more particularly to Fig. 1 of the drawing, numerals 1 and 2 designate rows of axially aligned headers or

collectors

3, 3' and 4, 4', 4", respectively. Groups of

parallel tubes

5, 5', and 5" are-connected with their ends to the'collec tors 3, 4; 4, 3'; 3', 4", respectively, collector 4 receiving the outlet ends of the pipe group 5 and the inlet ends of the following pipe group 5. The inlets and outlets of the tubes connected to the collectors ofthe same row are all at substantially the same elevation. The collectors forming the row 1 are placed in axially staggered relation to the collectors forming the row 2.

If the individual tubes are bent approximately in the middle of their length through 180 rectangularly to the plane of the drawing, arrangements are formed as shown in Figs. 2 and 3. In the modifications shown in these figures, the collectors of the individual rows 1 and 2 are formed by continuous tubes which are subdivided by transverse walls 6 to produce individual collector sections in the row 1 and by transverse walls 7 to produce individual collector sections in the row 2. The collector rows 1 and 2 are in close proximity of each other.

In the embodiment according to Fig. 2 the heating tubes 8, 8', 8 are bent like hairpins, one end of each tube being connected with a collector section of row 1 and the other end of each-tube being connected with a collector section of row 2, the sequence of the tubes and headers being the same as in Fig. l.

1n the embodiment shown in Fig. 3 the hairpin bends are replaced by relatively

short collectors

10, 10', 10", there being an individual collector for each pipe group 9, 9, 9", respectively. Instead of individual headers or

collectors

10, 10', 10", a continuous pipe, subdivided by transverse interior walls, may be provided in the same manner as the collectors forming the rows 1 and 2 in Fig. 2 are constructed. The tube ends connected with the intermediate collectors 10 preferably extend radially from the collectors and are connected with the collectors along diametrically opposed lines.

The collectors are preferably so placed that they are not directly exposed to the heat produced in the combustion chamber. They are either embedded in the brickwork (top of Fig. 4) or arranged outside of the brickwork or heat insulation (bottom of Fig. 4).

The hairpin bends of .the modification shown in Fig. 2 are also embedded in the brickwork or insulation (Fig. 5), or arranged outside thereof. The same is done with the 7 top.

The combustion chamber wall construction according I to the invention ensures reliable cooling of the walls and prevents blowing up and bursting of the tubes. Since in the arrangements according to Figs. 2 and 3 the tubes connected with different collectors are spaced, welding of the tube ends to the collectors is facilitated. It is also possible to space the tube ends in the arrangement according to Fig.1 to facilitate welding. A further advantage of the constructionis that individual tube units can easily be interchanged and relatively few replacement parts need be kept in stock. Brickwork can be reduced and even omitted with a combustion chamber wall according to the invention, since the walls are formed completely by the adjacent tubes. Cost is further, reduced because no downcomer tubes are needed.

The invention is not limited to the illustrated embodiments. The collectors need not be arranged in staggered relation. The number of tubes in the individual groups depends on the capacity of the steam generator, on the tube diameters, and on the desired flow velocity of the water and/ or steam. The combustion chamber wall construction according to the invention is of advantage also in steam generators which are operated at a pressure I.

lower than, but close to the critical pressure of water.

What is claimed is: 1. In a tubular lining for a combustion chamber wall of a forced flow steam generator, a plurality of parallel tubes, each tube having an inlet end and an outlet end,. a first and a second substantially parallel row 'of axially aligned substantially tubular headers placed at a right angle to said tubes at one end thereof, a row of axially aligned intermediate substantially tubular collectors placed at a right angle to said tubes at the other end thereof, the inlet ends of a first group of said tubes being connected with a first of said headers of said first row,

the outlet ends of the tubes of said first group being,

connected with a first of said intermediate collectors, the inlet ends of the tubes of a second group being connected with said first intermediate collector, the outlet ends of the tubes of said second group being connected with a first of said headers of said second row, a third group of said tubes having their inlet ends connected with said first header of said second row, the outlet ends of the tubes of said third group being connected with a second of said intermediate collectors, a fourth group of tubes having their inlet ends connected with said second intermediate collector and having their outlet ends connected with a second of said headers of the first row. the inlet ends of a fifth group of said tubes being connected with said second header of said first row, the outlet ends of said tubes of said fifth group being connected with a third of said intermediate collectors, the inlet ends of a sixth group of said tubes being connected with said third intermediate collector, and the outlet ends of the tubes of said sixth group being connected with a second header ofsaid second row of headers.

2. A tubular lining as defined in claim 1 in which said tube ends which are connected with said intermediate collectors extend substantially radially of the respective header, the outlet ends of the tubes of one group and the inlet ends of the tubes of the other group of tubes connected to the same intermediate collector.being connected with said intermediate collector along substantially diametrically opposed lines.

3. In a tubular lining for a combustion chamber wall of a forced flow steam generator, a first row of axially aligned substantially tubular headers, a second row of axially aligned substantially tubular headers, a first group of parallel tubes having inlet ends connected with a header of the first row and having outlet ends connected with a header of the second row, a second group of parallel tubes having inlet ends connected with said header of the second row and having outlet ends connected with a consecutive header of the first row, and intermediate collectors individuallyinterposed in said groups of tubes.

4. In a tubular combustion chamber wall lining according to claim 3 and wherein said first row of headers ,is-adjacent to and parallel to said second row of headers and at one end of the wall lined by said tubes, said collectors being arranged in said tubes substantially halfway between the inlet ends and the outlet ends of said tubes and at the other end of the wall lined by said tubes.

5. In a tubular combustion chamber wall lining according to claim 4 and wherein the tubes of a group which tubes extend between a header of the first row and the collector interposed in said group are interspersed between the tubes of the same group which tubes extend between said collector and a header of the second row.

6. In a tubular combustion chamber Wall lining according to claim 4 and wherein said tubes terminate in said collectors and extend from said collectors at substantially diametrically opposed locations.

References Cited in the file of this patent UNITED STATES PATENTS 320,647 Gannon June 23, 1885 1,959,866 Jacobus May 22, 1934 1,975,503 Engler Oct. 2, 1934 FOREIGN PATENTS 828,331 Germany Jan. 7, 1952 613,659 Germany May 23, 1935