Title of Invention	"A HEARTH FOR A CIRCULATING FLUIDIZED BED BOILER"
Abstract	A hearth for a circulating fiuidized bed boiler, the hearth including a floor built up from a set of elementary floors of smaller size, each being rectangular in shape, these elementary floors being juxtaposed so that the floor of the hearth constitutes a single piece, the hearth being characterized in that it is formed by an assembly of tubes, and in that it presents an area whose outer perimeter results from the use of a combination of vertical hearth faces and inwardly sloping hearth faces, thereby producing a floor whose outer perimeter, defined by more than four sides, presents re-entrant angles.

Title of Invention

"A HEARTH FOR A CIRCULATING FLUIDIZED BED BOILER"

Abstract

A hearth for a circulating fiuidized bed boiler, the hearth including a floor built up from a set of elementary floors of smaller size, each being rectangular in shape, these elementary floors being juxtaposed so that the floor of the hearth constitutes a single piece, the hearth being characterized in that it is formed by an assembly of tubes, and in that it presents an area whose outer perimeter results from the use of a combination of vertical hearth faces and inwardly sloping hearth faces, thereby producing a floor whose outer perimeter, defined by more than four sides, presents re-entrant angles.

Full Text	The present invention relates to hearth for a circulating fluidized bed (CFB) boiler, the hearth having a floor that ia made up of an assembly of tubes. The tubes are designed to be connected to inlet and outlet manifolds for a cooling fluid. The effectiveness with which solids are fluidized at tha bottom of the hearth is a function of the shape of its floor, and consequently of the shape of the screens forming the junction between the floor and the upper portions of the hearth. prier Art in known arrangements for the bottom of a hearth, tha floor is essentially square, rectangular, or circular in shape. The constraints on making a hearth floor for a circulating fluidized bed boiler are well known. In particular the dimensions; of the floor must: take account of the existence of a maximum value for the dissipation length of the jets of secondary air. Also the perimeter of the floor must be long enough to enable the floor to be carried if it is of the suspended type, or for loads to be transmitted if the hearth is of the standing type. Finally, and in all cases, the floor must be connected to the upper portions of the hearth via plane faces, The increasing power of circulating fluidized bed installations is leading to an ever- increasing number of connections that need to be made to the outer perineter of the floor, in particular for installing additional secondary air injection points, returns for solids coming from cyclones, etc. These additional connections are difficult, to provide with present floors, particulary when rectangular in shape, because of the lack of available room. The object of the invention is thus to propose a circulating fluidized bed boiler having a hearth whose floor is of an improved shape, making it possible to increase the number of rcnnecticns that car. be made to its perimeter while still complying with the constraints mentioned above. To this end the invention provides a hearth for a circulating fluidized bed boiler, the hearth including a floor made up of an assembly of tubes and in which the floor is built up from a set of elementary floors of smaller size, each being substantially rectangular in shape, these smaller floors being juxtaposed so that the floor of the hearth constitutes a single piece and presents an area whose perimeter is defined by more than four sides. In a particular embodiment of the invention, the floor area is H-shaped, which is particularly suitable for a hearth having an upper portion that is rectangular or square in section. In another particular embodiment of the invention, the floor area is in the shape of a cross, which is particularly suitable for a hearth having an upper portion that is octagonal in section. Accordingly, there is provided a hearth for a circulating fluidized bed boiler, the hearth comprising a floor built up from a set of elementary floors of smaller size, each being rectangular in shape, these elementary floors being juxtaposed so that the floor of the hearth constitutes a single piece, the hearth being characterized in that it is formed by an assembly of tubes, and in that it presents an area whose outer perimeter results from the use of a combination of vertical hearth faces and inwardly sloping hearth faces, thereby producing a floor whose outer perimeter, defined by more than four sides, presents reentrant angles. Examples of the invention are described below with reference to the accompanying drawings. Figure 1 is a highly diagrammatic view of a fluidized bed hearth having an H-shaped floor. Figure 2 shows in greater detail how the hearth and its floor are made from tubes. Figure 3 is a highly diagrammatic view of a fluidized bed hearth having a cross-shaped floor. In Figure 1, the top 1 of a circulating fluidized bed (CFB) boiler hearth is rectangular in section. For the hearth to work well, it is necessary for it to have vertical or inclined faces 2 or 3 of considerable length in order to re-inject solids coming from cyclones and from external beds, with the numbers thereof increasing with increasing power of the circulating fluidized bed. The hearth includes a floor 4 made up of an assembly of tubes 5 connected to fluid inlet and outlet manifolds such as 6. The floor 4 is built up from a set of elementary floors 4A, 4B, and 4C of smaller size, and ea.ch substantially rectangular in shape. These smaller floors 4A, 4B, and 4C are juxtaposed edge to edge, together building up a single-piece floor 4. The perimeter of the floor area is defined in this case by twelve sides, thereby making it possible in increase the number of connections that can be made around the perimeter of the floor, compared with a floor of equivalent area but in the form of a rectangle having four sides only. There is no difficulty in making a floor of this shape from tubes. Figure 2 shows a portion of the Figuro 1 floor. Each of the vertical screens such as 2, and of the eloping screens such as 3, is made up of an assembly of finned tubes 5 that are welded together to fcrm a leak-proof wall. They are fed with fluid from manifolds 6. In the bottom portion of the hearth, the tubes are connected to manifolds 6 and they are bent BO as to form a leak-proof wind box enabling the hearth the be fed with primary air, while also forming an H-shaped hearth floor. The junction between the floor 4 and the upper portion of the rectangular shaped hearth is also implemented in the form of tubes 5, which tubes are assembled together while leaving spacing of greater or lesser size between them. Inside the hearth, the faces cousLiLuLed by rubes are protected by a layer of refractory concrete 7. Figure 3 shows another embodiment in which the floor 4 of the hearth is built up from a set of elementary floors 4'A, 4'B, 4'C, 4'D, and 4'E, each of which is substantially rectangular in shape. The elementary floors 4'A to 4'E are juxtaposed edge-to-edge to constitute the overall floor 4. In this case the floor area is croes-shaped, and once again its perimeter is defined by twelve sides. CLAIM:- 1. A hearth for a circulating fluidized bed boiler, the hearth Comprising a floor (4) built up from a set of elementary floors (4A to 4C; 4'A to 4'E) of smaller size, each being rectangular in shape, these elementary floors being juxtaposed so that the floor (4) of the hearth constitutes a single piece, the hearth being characterized in that it is formed by an assembly of tubes (5), and in that it presents an area whose outer perimeter results from the use of a combination of vertical hearth faces (2) and inwardly sloping hearth faces (3), thereby producing a floor (4) whose outer perimeter, defined by more than four sides, presents re-entrant angles. 2. A hearth as claimed in claim 1, wherein the floor (4) is of an area that is H-shaped. 3. A hearth as claimed in claim 1, wherein the floor (4) is an area that is cross-shaped. 4. A hearth for circulating fluidized bed boiler, the hearth having a floor substantially as herein described with references to and as illustrated in the accompanying drawings.

Full Text

The present invention relates to hearth for a circulating fluidized bed (CFB) boiler, the hearth having a floor that ia made up of an assembly of tubes. The tubes are designed to be connected to inlet and outlet manifolds for a cooling fluid.
The effectiveness with which solids are fluidized at tha bottom of the hearth is a function of the shape of its floor, and consequently of the shape of the screens forming the junction between the floor and the upper portions of the hearth.
prier Art in known arrangements for the bottom of a hearth, tha floor is essentially square, rectangular, or circular in shape.
The constraints on making a hearth floor for a circulating fluidized bed boiler are well known. In particular the dimensions; of the floor must: take account of the existence of a maximum value for the dissipation length of the jets of secondary air. Also the perimeter of the floor must be long enough to enable the floor to be carried if it is of the suspended type, or for loads to be transmitted if the hearth is of the standing type. Finally, and in all cases, the floor must be connected to the upper portions of the hearth via plane faces,
The increasing power of circulating fluidized bed installations is leading to an ever- increasing number of connections that need to be made to the outer perineter of the floor, in particular for installing additional secondary air injection points, returns for solids coming from cyclones, etc. These additional connections are difficult, to provide with present floors, particulary when rectangular in shape, because of the lack of available room.
The object of the invention is thus to propose a circulating fluidized bed boiler having a hearth whose floor is of an improved shape, making it possible to increase the number of rcnnecticns that car. be made to
its perimeter while still complying with the constraints mentioned above.
To this end the invention provides a hearth for a circulating fluidized bed boiler, the hearth including a floor made up of an assembly of tubes and in which the floor is built up from a set of elementary floors of smaller size, each being substantially rectangular in shape, these smaller floors being juxtaposed so that the floor of the hearth constitutes a single piece and presents an area whose perimeter is defined by more than four sides.
In a particular embodiment of the invention, the floor area is H-shaped, which is particularly suitable for a hearth having an upper portion that is rectangular or square in section.
In another particular embodiment of the invention, the floor area is in the shape of a cross, which is particularly suitable for a hearth having an upper portion that is octagonal in section.
Accordingly, there is provided a hearth for a circulating fluidized bed

boiler, the hearth comprising a floor built up from a set of elementary floors of smaller size, each being rectangular in shape, these elementary floors being juxtaposed so that the floor of the hearth constitutes a single piece, the hearth being characterized in that it is formed by an assembly of tubes, and in that it presents an area whose outer perimeter results from the use of a combination of vertical hearth faces and inwardly sloping hearth faces, thereby producing a floor whose outer perimeter, defined by more than four sides, presents reentrant angles.
Examples of the invention are described below with reference to the accompanying drawings.
Figure 1 is a highly diagrammatic view of a fluidized bed hearth having an H-shaped floor.
Figure 2 shows in greater detail how the hearth and its floor are made from tubes.
Figure 3 is a highly diagrammatic view of a fluidized bed hearth having a cross-shaped floor.
In Figure 1, the top 1 of a circulating fluidized bed (CFB) boiler hearth is rectangular in section. For the hearth to work well, it is necessary for it to have vertical or inclined faces 2 or 3 of considerable length in order to re-inject solids coming from cyclones and from external beds, with the numbers thereof increasing with increasing power of the circulating fluidized bed.
The hearth includes a floor 4 made up of an assembly of tubes 5 connected to fluid inlet and outlet manifolds such as 6. The floor 4 is built up from a set of
elementary floors 4A, 4B, and 4C of smaller size, and ea.ch substantially rectangular in shape. These smaller floors 4A, 4B, and 4C are juxtaposed edge to edge, together building up a single-piece floor 4. The perimeter of the floor area is defined in this case by twelve sides, thereby making it possible in increase the number of connections that can be made around the perimeter of the floor, compared with a floor of equivalent area but in the form of a rectangle having four sides only.
There is no difficulty in making a floor of this shape from tubes.
Figure 2 shows a portion of the Figuro 1 floor. Each of the vertical screens such as 2, and of the eloping screens such as 3, is made up of an assembly of finned tubes 5 that are welded together to fcrm a leak-proof wall. They are fed with fluid from manifolds 6. In the bottom portion of the hearth, the tubes are connected to manifolds 6 and they are bent BO as to form a leak-proof wind box enabling the hearth the be fed with primary air, while also forming an H-shaped hearth floor.
The junction between the floor 4 and the upper portion of the rectangular shaped hearth is also implemented in the form of tubes 5, which tubes are assembled together while leaving spacing of greater or lesser size between them. Inside the hearth, the faces cousLiLuLed by rubes are protected by a layer of refractory concrete 7.
Figure 3 shows another embodiment in which the floor 4 of the hearth is built up from a set of elementary floors 4'A, 4'B, 4'C, 4'D, and 4'E, each of which is substantially rectangular in shape. The elementary floors 4'A to 4'E are juxtaposed edge-to-edge to constitute the overall floor 4. In this case the floor area is croes-shaped, and once again its perimeter is defined by twelve sides.

CLAIM:-
1. A hearth for a circulating fluidized bed boiler, the hearth Comprising
a floor (4) built up from a set of elementary floors (4A to 4C; 4'A to 4'E) of
smaller size, each being rectangular in shape, these elementary floors
being juxtaposed so that the floor (4) of the hearth constitutes a single
piece, the hearth being characterized in that it is formed by an assembly
of tubes (5), and in that it presents an area whose outer perimeter
results from the use of a combination of vertical hearth faces (2) and
inwardly sloping hearth faces (3), thereby producing a floor (4) whose
outer perimeter, defined by more than four sides, presents re-entrant
angles.
2. A hearth as claimed in claim 1, wherein the floor (4) is of an area
that is H-shaped.
3. A hearth as claimed in claim 1, wherein the floor (4) is an area
that is cross-shaped.
4. A hearth for circulating fluidized bed boiler, the hearth having a
floor substantially as herein described with references to and as
illustrated in the accompanying drawings.

Documents:

5-del-1998-abstract.pdf

5-del-1998-Assignment-(11-05-2012).pdf

5-del-1998-claims.pdf

5-del-1998-Correspondence Others-(11-05-2012).pdf

5-del-1998-correspondence-others.pdf

5-del-1998-correspondence-po.pdf

5-del-1998-description (complete).pdf

5-del-1998-drawings.pdf

5-del-1998-form-1.pdf

5-del-1998-form-13.pdf

5-del-1998-Form-16-(11-05-2012)-1.pdf

5-del-1998-Form-16-(11-05-2012).pdf

5-del-1998-form-19.pdf

5-del-1998-form-2.pdf

5-del-1998-form-3.pdf

5-del-1998-form-4.pdf

5-del-1998-form-6.pdf

5-del-1998-GPA-(11-05-2012).pdf

5-del-1998-gpa.pdf

5-del-1998-petition-137.pdf

5-del-1998-petition-138.pdf

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Patent Number

215270

Indian Patent Application Number

5/DEL/1998

PG Journal Number

10/2008

Publication Date

07-Mar-2008

Grant Date

22-Feb-2008

Date of Filing

01-Jan-1998

Name of Patentee

GEC ALSTHOM STEIN INDUSTRIE

Applicant Address

19-21, AVENUE MORANE SAULNIER, 78140 VELIZY-VILLACOUBLAY,FRANCE.

Inventors:

#	Inventor's Name	Inventor's Address
1	JEAN AUBRY	26 J, RUE PAUL RIVET 92350 LE PLESSIS ROBINSON, FRANCE.

PCT International Classification Number

F24B 9/04

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	97 00010	1997-01-02	France