US3105466A - Vapor generator - Google Patents

Description

R. H. EVANS VAPOR GENERATOR Oct; 1, 1963 4 Sheets-Sheet 1 Filed July 11, 1960 Inventor Richard Henry Evans 4 Attorney Oct. 1, 1963 R. H. EVANS 3,105,466

VAPOR GENERATOR Filed July 11, 1960 4 Sheets-Sheet 2 v In venlor A Home y R. H. EVANS 3,105,466

VAPOR GENERATOR Oct. 1, 1963 4 Sheets -Sheet 51 Filed July 11, 1960 I nventor- A (torn e y Oct. 1, 1963,

Filed July 11, 1960 R. H. Ev-A'Ns Y 3,105,466

VAPOR GENERATOR 4 Shee ts-Sheet 4 Inventor Attorney United States Patent @h ice Edd-5,466 Patented Get. 1,1963

3,105,466 VAPGR GENERATGR Richard Henry Evans, Surrey, England, assignor to Babcock & Wilcox, Limited, London, England, a company of Great Britain Filed July 11, 1969, Ser. No. 52,329 Claims priority, application Great Britain July 10, 1959 Claims. (Cl. 122-235) This invention relates to vapour generators of the kind having an upright furnace chamber provided with a firing zone in a lower region of the chamber and with a hopper bottom. Owing to the high rate of radiation to the hopper bottom walls in the neighbourhood of the firing zone it is desirable to line the hopper with contiguous wall tubes. In natural circulation boilers the tube lengths lining the hopper bottom walls are downward extensions of the upright furnace chamber wall tubes. Such a tube arrangement may also be adopted in the case of a forced flow boiler. In a forced flow boiler, however, the possibility arises of using horizontal tubes and the use of horizontal tubes sometimes otters advantages. More particularly, this invention is related to a forced flow tubulous boiler having circuits connected in parallel for flow of working medium and an upright furnace chamber space with walls lined by tube lengths of the circuits, wherein the tubulous lining has sections extending over respective zones one above the other and each formed by horizontal or substantially horizontal tube lengths of the respective circuits, the tube lengths of the circuim being distributed in the zones in a manner adapted to give approximately equal heat inputs to the circuits.

When furnace chamber wall areas are lined by horizontal or substantially horizontal tube lengths it is desirable that at least upper parts of hopper bottom wall areas should also be lined with horizontal or substantially horizontal contiguous tube lengths and it is important that the tubes should be drainable. If, as is usual, pairs of opposite hopper walls are respectively vertical and inclined, diificulty arises in maintaining both drainability of the tubes and contact between adjacent tubes.

A vapour generator according to the present invention includes an upright furnace chamber, a firing zone in a lower region of the chamber, horizontal or substantially horizontal tube lengths arranged to operate with forced flow of the working medium therethrough lining areas of the furnace chamber walls and wall areas of a furnace chamber hopper bottom, tube lengths over at least an upper part of the furnace chamber hopper bottom being contiguously arranged to define wall surfaces of the several walls which surfaces slope at the same or substantially the same inclination.

The invention will now be described, by way of example, with reference to the accompanying, partly diagrammatic drawings, in which:

FIGURE 1 is an isometric elevation of a lower part of a steam generating and superheating unit having a hopper bottom;

FIGURE 2 is a fragmentary sectional elevation taken on the line 11-11 of FIGURE 1;

FIGURE 3 is a fragmentary sectional elevation taken on the line III-J11 of FIGURE 1;

FIGURE 4 is an isometric elevation of an alternative arrangement of a hopper bottom of a steam generating and superheating unit;

FIGURE 5 is a front elevation of an alternative arrangement of tubes lining a hopper bottom; and

FIGURE 6 is a sectional side elevation taken on the line VI-VI of FIGURE 1.

A furnace chamber 2 of a steam generating and superheating unit, a lower portion of which is shown in FIG- URE 1, is lined with tubes 4 connected into the fluid circulation system of a forced-flow tubulous boiler having circuits connected in parallel for the flow of working medium. The walls of the furnace chamber 2 are lined with horizontal tube lengths of the circuits located in sections extending over respective zones one above the other, the tube lengths being arranged in groups providing sets 6 of adjacent tube length ends distributed around the furnace chamber 2. The sets 6 of tube length ends each includes inlet ends and outlet ends and upright transfer or connector tubes 8 leading to the inlet ends of each of the said sets 6 are coupled to superjacent transfer or connector tubes 8 leading from the outlet ends of the set, the said transfer or connector tubes 8 constituting part of suspension means for the section. The transfer or connector tubes 8 are arranged in vertically extending sets distributed around the furnace chamber 2.

The furnace chamber 2 includes a firing zone 10 at which a front wall 12 is provided with burner ports 14. In the neighbourhood of the ports 14 the wall 12 is lined with a group 16 of upright tubes extending between a lower header 15 and an upper header 17. Those of the horizontal tubes 4 lying intermediate the ports 14 extend horizontally transversely of the group 16 of upright tubes. Others of the tubes 4 at the levels of the ports 14 are bent outwardly and upwardly at one side of the group 16 and extend across the front wall 12 clear of the burners and intermediate the ports 14. The tubes are further bent upwardly and inwardly to re-enter the front wall 12 adjacent the other side of the group 16 of upright tubes at a higher level.

A hopper bottom 13 is provided with tubes 2% lining the walls thereof, the tubes in an upper portion 22 being arranged contiguously. The four walls of the upper portion 22 of the hopper 18 slope inwardly in a downward direction at similar inclinations. The front wall 24 of the hopper bottom 18, at a level somewhat below the mid-plane in the height of the hopper bottom, continues downwardly at a reversed slope to form the front wall of a lower portion 25 at an inclination substantially equal to that of the upper portion of the wall. The rear wall 26 continues downwardly at the same slope to a somewhat lower level there the wall continuing downwardly with a reversed slope having an inclination substantially equal to that of the upper portion of the wall so that the lower extremities of the front and rear walls flare outwardly. The side walls 27 at the level of the change of slope of the front walls 2 continue downwardly in a vertical plane.

The tubes 20 lining the hopper bottom 18 are arranged in eight parallel passes 28, each pass extending upwardly from a lower, drainable, distributor 30 in a sinuous or meandering manner to upper, drainable, collectors 32 discharging through connectors 33 to a lower distributor 34.

Each pass 28 includes horizontally extending tube lengths arranged in parallel flow relationship in legs A, B, C, D, E, F, G and H, respective ends of tube lengths of adjacent legs being connected by upright tube portions.

As shown in FIGURE 2, the front and rear walls 24, 26 are lined with the tubes 20 arranged in spaced rela tionship in the lower legs A, B and in contiguous relationship in the upper legs C, D, E, F, G, H. The tubes in the lower legs A, B are provided with longitudinal fins 38 extending into the gaps between the tubes. Alternatively, the tubes may be provided with studs and the gaps filled with refractory material. Since the tubes 20 of the lowermost leg A are spaced apart, respective tubes can be connected with horizontally extending tube lengths 36, the slope of the wall and the spacing of the tubes in the wall being such that there is no interference between a tube length 36 connecting with one of the tubes 20 and 3 an adjacent tube length 36 connecting with an adjacent tube 20, and tubes 20 arranged in spaced relationship in the wall when bent at right angles to lie with their axes in a vertical plane are arranged contiguously. Respective tubes 20 of the uppermost leg H are connected with tube lengths 4t) discharging to the upper collector 32. Since the tubes 29 in the uppermost leg H are arranged contiguously, the tube lengths 46 extend downwardly from the leg H with their axes perpendicular to the plane containing the axes of the tubes 20 in the uppermost leg H, thereby avoiding interference between adjacent tube lengths 40 and tubes 20.

As shown in FIGURE 3, the side walls 27 are lined with the tubes 20 arranged contiguously. Since the lower parts of the walls 27 lined by the lower legs A, B are vertical, respective tubes 2% connect with the horizontal tube lengths 36 without interference between adjacent tubes 20 and the tube lengths 36. Parts 29 of the tubes 20 of the lower legs A, B extending into the front and rear walls 24, 26 are arranged in spaced relationship due to the axes of the tubes 20 lining the lower parts of the side walls 27 being in vertical planes and the axes of the tubes lining the lower parts of the front and rear walls 24, 26 being in planes inclined to the vertical. The parts 29 of the tubes 20 are provided with longitudinal fins or studs and refractory material filling the gaps between the parts. Respective contiguously arranged tubes 20 of the uppermost leg H are connected with the tube lengths 40 extending downwardly from the leg H with their axes perpendicular to the plane containing the axes of the tubes 20 in the uppermost leg H, thereby avoiding interference between adjacent tube lengths 40 and tubes 20.

In operation, feed water is supplied from economizers (not shown) to the lower header of the upright tube group 16 and is discharged to the upper header 17. From the upper header 17 the Water flows through connectors 41 to the lower distributor 30 and flows, in parallel passes, through the tubes lining the hopper 18 to the upper collectors 32 which discharge to the lower distributor 34. The water then flows, in parallel passes, through the transfer tubes 8 to the tubes 4 lining the furnace chamber 2, the flow being in a generally upward direction, the tubes discharging to upper headers (not shown) connecting with the remaining parts of the unit.

It will be understood that by sloping all of the walls of the upper portion 22 of the hopper 18 at the same inward inclination, the tubes lining the upper portion 22 may be arranged contiguously thereby achieving an economy in cost over an arrangement in which the tubes are spaced apart and require the provision of suitable fins or studs and refractory material to fill the gaps between tubes. Since the tube lengths 36 of the tubes 20 extend horizontally and downwardly into the lower, drainable, distributor and the tube lengths 40 extend downwardly into the upper, drainable, collector 32, complete draining of the tubes 20 is possible.

In the alternative arrangement of a hopper bottom shown in FIGURE 4, a hopper bottom 42 is lined with tubes 44 and is formed with an upper portion 46 having walls sloping inwardly in a downward direction at similar inclinations and lined with the tubes 44 arranged contiguously. The front wall 48 of the hopper 42, at a level somewhat below the mid-plane in the height of the hopper, continues downwardly at a reversed slope having an inclination substantially equal to that of the part of the front wall in the upper portion 46. At a somewhat lower level the rear wall 50 also continues downwardly with a reversed slope substantially equal to that of the part of the rear wall in the upper portion 46 so that the 7 lower extremities of the front and rear walls 48 and 50 flare outwardly, Below the level of the upper portion 46 of the hopper 42 the side walls 51 extend downwardly in vertical planes. Below the level of the upper portion 46 the tubes 44 are arranged in spaced relationship in the front and rear walls 48, 50 the gaps between the tubes being filled with longitudinal fins or with studs and refractory material, and in continguous relationship in the side walls 5-1.

The tubes 44 lining the hopper 42 are arranged in a number of parallel passes, two tubes lengths 52, 54 of a pass only being shown for the sake of clarity. The tube lengths 52, 54 extend upwardly from a lower, drainable, distributor 56 and horizontally into the front wall 48 of the hopper 42 to extend in opposite directions around the hopper to transfer portions 58, 60 extending horizontally from the rear wall and upwardly to the upper portion 46 of the hopper bottom 18, parts 59, 61 of the tube portions 53, 6% connecting into the rear wall 50 being arranged normal to the rear wall. The tube lengths 52, 54 then extend in opposite directions around the upper portion 46 of the hopper 42 to connector portions 62, 64 arranged normal to the front wall 48 and leading from the front wall to a drainable collector 66. The collector 66 discharges through transfer tubes 68 to a distributor 70 connected with the remainder of the unit.

In operation water is supplied to the distributor 56, flows in a generally upward direction through the tubes 44 lining the hopper 42 and is discharged to the collector 66 which in turn discharges to the distributor 70'.

It will be understood that, as in the arrangement previously described, sloping of all of the walls of the upper portion 46 of the hopper 42 at the same inclination permits contiguous arrangement of the tubes '44 lining the upper portion 46, thereby achieving an economy in cost over an arrangement in which the tubes are spaced apart and require the provision of suitable fins or studs and refractory material to fill the gaps between the tubes. Also, since the tubes 44 extend upwardly from the lower, drainable, distributor 56 and connecting portions of the tubes 44 extend downwardly to the drainable collectors 66, complete draining of the tubes is possible.

In the tube arrangement shown in FIGURES 5 and 6 of the drawings, tubes 72 lining a hopper bottom are arranged in eight parallel passes, one of which is shown in FIGURES 5 land 6, and which ascend the walls of the hopper bottom in a sinuous or meandering manner similar to that shown in FIGURE 1. The hopper bottom is formed with an upper part, the four walls of which extend downwardly and inwardly at the same inclination, and a lower part, the four walls of which extend downwardly and outwardly at the same inclination.

The tubes 72 extend alternately upwardly from opposite sides of a drainable inlet header 74, then extend horizontally into a wall 76 and are bent in an upward direction to lie in the plane of the adjacent part of the wall, the tubes being positioned in a contiguous manner. The tubes 72 are then bent to extend horizontally to form a first leg 78 of a pass 80 lining a part of the wall 76.

At the top of the hopper bottom wall 76, the tubes 72 included in a last leg 82 of the pass 80 are bent to extend upwardly in the plane of the wall and are then bent to extend horizontally outwardly from the wall 76. The tubes 72 are then bent upwardly to connect alternately into opposite sides of an outlet header 84.

The remaining parts of the walls of the hopper bottom are lined in a like manner by further tubes 72 arranged in other passes similar to the pass 80.

Since all of the walls of the upper portion 86 of the hopper bottom, extend at the same downward and inward inclination, and since all of the walls of the lower portion 88 of the hopper bottom extend at the same downward and outward inclination, the tubes 72 maybe arranged contiguously throughout their lengths lining the walls of the hopper bottom, thereby achieving an economy in cost over an arrangement in which some or all of the tubes are spaced apart and require the provision of suitable fins or studs and refractory material to fill the gaps between the tubes. Also, since the tubes 72 extend in a generally upward direction from the d-rainable inlet header 74 to the outlet header 84, complete draining of the tubes is possible.

I claim:

1. In combination with a vapor generator, means forming a furnace confining high temperature gases, walls forming a hopper opening to the lower end of said furnace and having a lower portion of gradually decreasing horizontal cross-sectional area in an upward direction and an upper portion of gradually increasing horizontal crosssectional area in an upward direction, each of the wall surfaces of said upper and lower portions of the hopper including a group of horizontally extending vertically spaced drainable fluid cooled tube lengths arranged for parallel flow of fluid therethrough, all the wall surfaces of said upper portion of the hopper sloping at substantially the same inclination and the tube lengths of the wall surfaces of the upper portion of the hopper being contiguously arranged, header means supplying fluid in parallel flow relation to the groups of tube lengths of the wall surfaces of the lower portion of the hopper, drainable tubular means connecting each group of tube lengths of each wall surface of the lower portion of the hopper for series flow of fluid to the group of tube lengths of the corresponding wall surface of the upper portion of the hopper and providing a flow of fluid continuously in an upward direction between the tube lengths of the walls of the lower and upper portions of the hopper, and means supplying fluid to said header means.

2. In combination with a vapor generator, means forming a furnace confining high temperature gases, walls forming a hopper opening to the lower end of said furnace and having a lower portion of gradually decreasing horizontal cross-sectional area in an upward direction and an upper portion of gradually increasing horizontal crosssectional area in an upward direction, each of the wall surfaces of said upper and lower portions of the hopper including a group of horizontally extending drainable fluid cooled tube lengths arranged for parallel flow of fluid therethrough, all the wall surfaces of said upper portion of the hopper sloping at substantially the same inclination, a continuous header supplying fluid in parallel flow relation to the groups of tube lengths of the wall surfaces of the lower portion of the hopper, drainable tubular means connecting each group of tube lengths of each wall surface of the lower portion of the hopper for series flow of fluid to the group of tube lengths of the corresponding wall surface of the upper portion of the hopper and providing a flow of fluid continuously in an upward direction between the tube lengths of the walls of the lower and upper portions of the hopper, means supplying fluid to said continuous header, and a plurality of collector headers, and sets of connector tubes each extending normal to and connecting a group of the tube lengths of the wall surfaces of the upper portion of the hopper for flow of fluid to one of said collector headers.

3. In combination with a vapor generator, means forming a furnace confining high temperature gases, walls forming a hopper opening to the lower end of said furnace and having a lower portion of gradually decreasing horizontal cross-sectional area in an upward direction and an upper portion of gradually increasing horizontal cross-sectional area in an upward direction, each of the wall surfaces of said upper and lower portions of the hopper including a group of horizontally extending vertically spaced drainable fluid cooled tube lengths arranged for parallel flow of fluid therethrough, all the wall surfaces of said upper portion of the hopper sloping at substantially the same inclination and the tube lengths of the wall surfaces of the upper portion of the hopper being contiguously arranged, header means supplying fluid in parallel flow relation to the groups of tube lengths of the wall surfaces of the lower portion of the hopper, drainable tubular means connecting each group of tube lengths of each wall surface of the lower portion of the hopper for series flow of fluid to the group of tube lengths of the corresponding wall surface of the upper portion of the hopper, and means supplying fluid to said header means, the front and rear walls of the lower portion of said hopper converging in an upward direction and the tube lengths thereof being arranged in spaced relationship and having their intertube spaces closed by metallic fins, the side walls of the lower portion of said hopper being vertically arranged and the tube lengths thereof being contiguously arranged.

4. In combination with a vapor generator, means forming a furnace confining high temperature gases, walls forming a hopper opening to the lower end of said furnace and having a lower portion of gradually decreasing horizontal cross-sectional area in an upward direction and an upper portion of gradually increasing horizontal cross-sectional area in an upward direction, each of the wall surfaces of said upper and lower portions of the hopper including horizontally extending vertically spaced drainable fluid cooled tube lengths arranged for parallel flow of fluid therethrough, all of the Wall surfaces of the lower portion of the hopper sloping upwardly and inwardly at substantially the same inclination, all the wall surfaces of said upper portion of the hopper sloping upwardly and outwardly at substantially the same inclination and the tube lengths of the wall surfaces of the upper portion of the hopper being contiguously arranged, header means supplying fluid in parallel flow relation to the groups of tube lengths of the wall surfaces of the lower portion of the hopper, drainable tubular means connecting each group of tube lengths of each wall surface of the lower portion of the hopper for series flow of fluid to the group of tube lengths of the corresponding wall surface of the upper portion of the hopper and providing a flow of fluid continuously in an upward direction between the tube lengths of the walls of the lower and upper portions of the hopper, and means supplying fluid to said header means.

5. in combination with a vapor generator, means forming a furnace confining high temperature gases, walls forming a hopper opening to the lower end of said furnace and having a lower portion of gradually decreasing horizontal cross-sectional area in an upward direction and an upper portion of gradually increasing horizontal cross-section area in an upward direction, each of the walls of said upper and lower portions of the hopper being lined by horizontally extending vertically spaced drainable fluid cooled tube lengths, means interconnecting the tube lengths of each of the walls of the lower portion of the hopper for series flow of fluid to the tube lengths of one of the walls of the upper portion of the hopper and providing a flow of fluid continuously in an upward direction between the tube lengths of the walls of the lower and upper portions of the hopper, and means supplying fluid to the tube lengths of the walls of the lower portion of the hopper.

References Cited in the file of this patent UNITED STATES PATENTS 3,007,459 Koch Nov. 7, 1961 FOREEGN PATENTS 1,154,626 France Nov. 4, 1957 1,185,795 France Feb. 16, 1959 OTHER REFERENCES German application 1,054,642 printed April 9, 1959 (K1. 241 8).

Claims (1)

1. IN COMBINATION WITH A VAPOR GENERATOR, MEANS FORMING A FURNACE CONFINING HIGH TEMPERATURE GASES, WALLS FORMING A HOPPER OPENING TO THE LOWER END OF SAID FURNACE AND HAVING A LOWER PORTION OF GRADUALLY DECREASING HORIZONTAL CROSS-SECTIONAL AREA IN AN UPWARD DIRECTION AND AN UPPER PORTION OF GRADUALLY INCREASING HORIZONTAL CROSSSECTIONAL AREA IN AN UPWARD DIRECTION, EACH OF THE WALL SURFACES OF SAID UPPER AND LOWER PORTIONS OF THE HOPPER INCLUDING A GROUP OF HORIZONTALLY EXTENDING VERTICALLY SPACED DRAINABLE FLUID COOLED TUBE LENGTHS ARRANGED FOR PARALLEL FLOW OF FLUID THERETHROUGH, ALL THE WALL SURFACES OF SAID UPPER PORTION OF THE HOPPER SLOPING AT SUBSTANTIALLY THE SAME INCLINATION AND THE TUBE LENGTHS OF THE WALL SURFACES OF THE UPPER PORTION OF THE HOPPER BEING CONTIGUOUSLY ARRANGED, HEADER MEANS SUPPLYING FLUID IN PARALLEL FLOW RELATION TO THE GROUPS OF TUBE LENGTHS OF THE WALL SURFACES OF THE LOWER PORTION OF THE HOPPER, DRAINABLE TUBULAR MEANS CONNECTING EACH GROUP OF TUBE LENGTHS OF EACH WALL SURFACE OF THE LOWER PORTION OF THE HOPPER FOR SERIES FLOW OF FLUID TO THE GROUP OF TUBE LENGTHS OF THE CORRESPONDING WALL SURFACE OF THE UPPER PORTION OF THE HOPPER AND PROVIDING A FLOW OF FLUID CONTINUOUSLY IN AN UPWARD DIRECTION BETWEEN THE TUBE LENGTHS OF THE WALLS OF THE LOWER AND UPPER PORTIONS OF THE HOPPER, AND MEANS SUPPLYING FLUID TO SAID HEADER MEANS.

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