US3395677A - Tube lining for prismatic combustion chambers - Google Patents

Description

ug- 1958 G. BRANDSTETTER 3,395,677

TUBE LINING FOR PRISMATIC COMBUSTION CHAMBERS Filed Feb. 1, 1967 Inventor: G-Zzone BRANDSTETTER AT'TO E V5 United States Patent 3,395,677 TUBE LINING FOR PRISMATIC COMBUSTION CHAMBERS Georg Brandstetter, Boblingen, Germany, assignor, by

mesne assignments, to Sulzer Brothers, Ltd., Winterthur, Switzerland, a corporation of Switzerland Filed Feb. 1, 1967, Ser. No. 613,178 Claims priority, application Germany, Feb. 4, 1966, K 58,334 1 Claim. (Cl. 122235) ABSTRACT OF THE DISCLOSURE A tube lining for prismatic combustion chambers having funnels in the lower end. The tube lining portions on vertical walls of the funnel are bent under the tube lining portions on inclined walls of the funnel to overlap the tube lining portions with each other. The overlap covers any space between the reversals of the tube lining portions with respect to the plate jacket surrounding the combustion chamber to prevent heat radiation from within the chamber to pass to the plate jacket.

This invention relates to a tube lining for prismatic combustion chambers. More particularly, this invention relates to a tube lining for prismatic combustion chambers having funnels in the lower end zones.

Heretofore, prismatic combustion chambers with funnels disposed at the lower zones have been lined with tube linings of tube strip groups. These tube strip groups have been connected in parallel relation and have extended to and fro vertically or horizontally so as to extend in vertical planes. The external boundary for such combustion chambers has been formed by a plate jacket disposed directly behind these tubes while bearing directly thereon.

Such tube linings have been employed for forced circulation boilers and once-through forced flow boilers be cause the use of gas-tight walls free of brickwork has been found favorable for the reliable and efiicient operation of such boilers. However, difficulties have arisen relative to the plate jacket with tube strips extending to and fro since it has not been possible to avoid substantial spaces even if the tubes have been closely spaced, particularly if the reversals have not extended at right angles as is the case in the tube strips of combustion chamber walls which constrict in the funnel zone. The plate jacket disposed behind these spaces has thus been exposed to such a severe heat radiation that it has been destroyed in time.

The frequently selected method of welding fins to the tubes for protecting the plate jacket in the zone of the bends and thus to withdraw the plate jacket from the efiects of heat radiation cannot be employed with the aforementioned reversal positions because the surfaces to be covered are too large so that the fins are unable to dissipate the radiated heat with suflicient rapidity into the tubes.

Briefly, this invention provides a combustion chamber having a funnel disposed in a lower zone and a plate jacket with a tube lining formed of tube strip groups wherein the tube strip groups serving to line the combustion chamber walls which converge with the inclined funnel walls are bent at their joints with the inclined funnel walls with the reversals of such tube strip groups disposed behind the tube strip groups lining the inclined walls of the funnel while extending within the plane of the com bustion chamber walls. The spaces between the reversal bends of the individual tubes and the tube strip groups are consequently always covered by the tubes of the adjacent walls. Thus, excessive heat radiation acting on the plate 3,395,677 Patented Aug. 6, 1968 jacket from within the combustion chamber is eliminated so that reliable boiler operation can be subsequently obtained with this essential prerequisite to such satisfied.

Accordingly, it is an object of this invention to construct a combustion chamber tube lining of tube strips in the zone of the tube strip reversals so as to protect a plate jacket behind the tube strips from heat radiation.

It is another object of this invention to prevent excessive heat radiation from acting on a plate jacket of a prismatic combustion chamber in a funnel shaped lower zone.

These and other objects and advantages of the invention will become more apparent from the following detailed description and appended claims taken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a vertical section taken on line II of FIG. 2 through the funnel of a forced circulation boiler; and

FIG. 2 illustrates a plane view of the funnel of FIG. 1.

Referring to FIGS. 1 and 2, combustion chamber 1 is terminated at the bottom by a cuniform funnel 2 and is provided with a tube lining. A plate jacket is disposed immediately behind the tube lining while being in hearing contact therewith to bound the combustion chamber 1 towards the exterior. The tube strips 6 which continue above the funnel 2 in the combustion chamber walls have lower reversals 5 in the plane of the inclined funnel walls 4. The tube strips 9 serving to line the vertical funnel walls which constrict in accordance with the inclination of the funnel are bent at their joints with the inclined funnel walls 4 and have reversals 8 disposed below the tube strips 6 between the tube strips 6 and plate jacket 3.

The tube strips 6 and 9 are dimensioned so that the spaces between the reversal bends of the individual tubes and the tube strips of one wall are covered by the tubes of the tube strips running along the adjacent wall. Thus, any excessive heat radiation from within the combustion chamber 1 is prevented from acting on the plate jacket 3.

Having thus described the invetnion it is not intended that it be so limited as changes may be readily made therein without departing from the scope of the invention. Accordingly, it is intended that the subject matter described above and shown in the drawings be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In combination with a prismatic combustion chamher having a cuniform funnel of inclined walls and converging walls disposed at the lower end thereof; a tube lining for lining said combustion chamber having a plurality of tube strip groups connected in parallel to extend to and fro horizontally or vertically, said tube strip groups lining said converging walls being bent at the joint of said converging walls with said inclined walls and being formed with reversals disposed behind the tube strip groups lining said inclined walls within the plane of said walls, and a plate jacket disposed directly behind said tube lining in bearing contact therewith to bound said combustion chamber to the exterior thereof.

References Cited UNITED STATES PATENTS 1,811,657 6/1931 Wood. 3,105,466 10/1963 Evans 122-235 FOREIGN PATENTS 1,054,283 10/ 1953 France.

368,815 6/ 1963' Switzerland.

CHARLES J. MYHRE, Primary Examiner.

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