US3233597A

US3233597A - Apparatus for forming openings in furnace walls

Info

Publication number: US3233597A
Application number: US334522A
Authority: US
Inventors: Konrad S Svendsen
Original assignee: Combustion Engineering Inc
Current assignee: Combustion Engineering Inc
Priority date: 1963-12-30
Filing date: 1963-12-30
Publication date: 1966-02-08
Anticipated expiration: 1983-02-08
Also published as: FR1417863A

Description

Feb. 8, 1966 K. s. SVENDSEN 3,233,597

APPARATUS FOR FORMING OPENINGS IN FURNACE WALLS Filed Dec. 30, 1963 2 SheetsSheet 1 V INVENTOR: Kommo 5. SVENDS'EN BY m HGENT Feb. 8, 1966 K. S. SVENDSEN APPARATUS FOR FORMING OPENINGS IN FURNACE WALLS Filed Dec. 30, 1963 FIG. 5

2 Sheets-Sheet 2 INVENTOR:

KO/VRADi 5VEN05EN BY/%%@W APPARATUS FOR FORMING OPENINGS IN FURNACE WALLS Konrad S. Sven'dsen, Bloomfield, Conn., assignor to Combustion Engineering, Inc., Windsor, Conn, a corporation of Delaware Filed Dec. 30, 1963, Ser. No. 334,522 4 Claims. (Cl. 122-235) This invention relates to openings in water cooled fur nace walls. More specifically, the invention is concerned with means and a method of forming an opening in a furnace wall lined with water cooled parallel tubes that are closely spaced and welded to form a gas tight furnace enclosure.

In large water cooled furnaces such as those employed in connection with modern steam generators a great number of openings are required in the furnace walls. These furnace walls are lined on the inside or fire side thereof with water carrying and parallelly arranged tubes. Several inches of insulation is applied on the outside, which insulation is further enclosed by a metallic casing. In order to avoid hot spots or burning of the tube surface the flow of the cooling fluid (usually water) must be maintained continuously through the tubes even at the places where an opening in the wall is provided. Accordingly, the tubes must be bent aside sufficiently to form a large enough opening between the tubes for access by sootblowers, instrument inserts, observation ports, etc.

Heretofore, this has been accomplished by bending a first tube away from the tube plane in a direction normal to this plane. Thus a space was provided for the &- setting of another adjacent tube which tube then could be bent in the wall plane so as to occupy the space formerly taken up by the first tube. When bending tubes to form an access opening in a tubular furnace wall, it is also desirable that the tubes which are bent away from the wall plane remain within the normal space needed for the insulation between the tube wall and the metallic casing. Accordingly, in order to provide an access opening two tubes wide by the above earlier method, four tubes had to be offset or a total of sixteen bends had to be provided in the past to form one access opening. Since a considerable number of access openings (such as 100 to 150) must be provided in the furnace wall of a large steam generator, this earlier practice of forming an opening by bending four tubes proved to be very expensive. Furthermore, in using this construction it is also quite difficult to seal the tubular structure surrounding the opening so as to obtain a gas tight construction.

These conditions have been greatly improved by the herein disclosed method and structure for forming access openings in water cooled tubular furnace walls. In accordance with the invention this is accomplished by reducing thenumber of tubes that must be offset by half, and still retain those tubes within the normal space pro vided between the casing and the tube lining for "insulation. Furthermore, the herein disclosed structure permits less expensive and more effective gas tight sealing of the tubular structure forming the access opening.

It is accordingly an object of the invention to provide openings in the water cooled tubular walls of a furnace chamber in a manner which reduces the construction costs thereof considerably.

It is another object of the invention to provide a tubular structure for forming an opening in a tubular wall, which structure can be sealed against furnace pressure and radiant heat with greater efficiency and effectiveness.

Other objects and advantages of the invention will become apparent from the following description of an il- United States Patent O 2,233,597 Patented Feb. 8 1966 l'lLStIfltllVC embodiment thereof, when taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a cross-section taken through a tubular furnace wall wherein one tube has been bent out of the Way to permit access to the furnace chamber.

FIG. 2 is an elevational view of the tube lining when taken at line 2-42 of FIG. 1.

FIG. 3 is a cross-section through the tubular wall when taken at line 3-3 of FIG. 1.

FIG. 4 is a cross-section through a tubular furnace wall wherein two tubes have been bent out of the way to permit access to the furnace chamber.

FIG. 5 is an elevational view of the tube lining when taken at line 55 of FIG. 4. l

FIG. 6 is a cross-section through the tubular wall when taken at line 6-45 of FIG. 4.

Referring now to the drawings wherein like reference characters are used throughout to designate like elements, the illustrative and preferred embodiment of the invention depicted therein includes a tubular wall 10 of a furnace chamber. Wall 10 comprises a plurality of parallel tubes 12 lining the fire side of the furnace wall. These tubes are closely spaced and are preferably Welded to each other along their length at 14, to form a gas tight enclosure for the combustion gases. Insulation preferably in the form of insulating blocks of suitable thickness is applied at the outside of the tube well such as at 16. The furnace wall then completely enclosed by a metallic casing 18.

FIGS. 1, 2 and '3 disclose a structure defining a wall opening 19 of relatively small width such as one tube wide. To form this opening a portion ofa single tube 20 is bent away from the wall plane 22 such as by a double offset. This double offset comprises a first oifset 23 bending the tube in a direction away from the wall plane 22 anda second offset 24 bending the tube 20 in a direction towards and back into the wall plane 22. The first and second offsets are executed in an offset plane 25 which forms an acute angle 26 with the wall plane or tube plane 22. In order to produce a double offset in such a manner that the bent portions thereof remain within the space provided for insulation 16 a third bend 28 is applied to the offset portion of tube 20. This third bend 28 imparts to the tube offset a curvature which follows the contour or periphery of an imaginary curved bod-y or body of rotation 30 indicated by a dot and dash line. This curvature is so applied that the concave side thereof faces the tube plane 22. The axis 32 of the curved body or body of rotation 30 is preferably maintained in parallel relation with the wall plane 22 or with tubes "12. Suitable inserts 33 and 34 are welded to the offset portion of tube 20 and to adjacent tube 36 and to a conduit portion 37 which defines the access opening .19 for the passing therethrough of a sootblower or instrument insert or the like;

FIGS. 4, 5 and 6 disclose a structure defining a wall opening 39 of approximately twice the width than that illustrated in FIGS. 1, 2 and 3. To form this opening portions of two

adjacent tubes

40 and 41 are bent in opposite directions and away from the wall plane 42 such as by a double offset. This double offset comprises a first ofiset 43 bending each tube 40 and 4 1 in mutually diverging directions and away from the wall plane 42, and a second otfset 44 bending each

tube

40 and 41 in mutually converging directions and towards and back into the wall plane 42. Pairs of the first and second offsets are executed in two opposing planes 45 and 46, respectively, which form acute angles 47 and 48, respectively, with the wall or tube plane 42. These acute angles are of opposite configuration so that the apexes thereof face each other.

Again as in FIGS. 1, 2 and 3, in order that the bent portions of

tubes

40 and 41 remain within the space normally allotted to insulating blocks 16, an additional bend 50 is applied to each of the opposite portions of

tubes

40 and 41. Each of said bends 50 follows the periphery of an imaginary curved body or body of

rotation

52 and 54 as indicated in dot and dash lines. The

respective axes

56 and 58 of these curved bodies or bodies of rotation are preferably maintained in parallel relation with the wall plane 42 and with tubes L2, and are however located so as to be outwardly spaced from opposite sides of said opening 39. Suitable inserts 60 and 62 are welded to the opposite portions of tubes 40 and 4:1 and to

adjacent tubes

64 and 66, and to conduit portion 68 which defines the access opening for the passing therethrough of sootblower elements or insertion of observation doors and the like.

While I have illustrated and described a preferred embodiment of my invention it is to be understood that such is merely illustrative and not restrictive and that variations and modifications may be made therein without departing from the spirit and scope of the invention. I

therefore do not wish to be limited to the precise details set forth but desire to avail myself of such changes as fall within the purview of my invention.

I claim:

.1. In a furnace wall the combination of a wall lining on the heated side of said furnace Wall, comprising a plurality of heat absorbing and fluid cooled tubes parallelly disposed in one plane, said tubes being mutually spaced a distance substantially less than the tube diameter, means for forming an access opening in said wall lining, said opening having a width that is at least equal to the distance between two alternate tubes, said means comprising a double offset in one of said plurality of tubes, said double offset having a first offset bending said tube in a direction away from the heated side of said wall and away from the center of said opening, and a second offset bending said tube in a direction toward and back into said plane, the depth of said offset being at least sufficient to place the offset portion of said tube outside of said width when viewed in a direction normal to said one plane, and a bend applied to said double offset, said bend following the periphery of an imaginary body of rotation having an axis directed transversely to the direction of said double offset, and with the concave side of said bend facing said one plane.

2. In a refractory furnace wall the combination of a wall lining on the heated side of said furnace wall, cornprising a plurality of heat absorbing and fluid cooled tubes paralle-lly disposed in one plane, said tubes being mutually spaced a distance substantially less than the tube diameter and lined on the cool side thereof with casing means,

means for forming an access opening in said wall lining,

said means comprising a double offset in one of said plurality of tubes, said double offset generally lying in a plane forming an acute angle with said one plane and extending in a direction away from said heated side, and a bend applied to said double offset, said bend following the periphery of an imaginary elongated curved body of rotation having a longitudinal axis directed transversely to 'the direction of said double offset, said bend being of limited dimension such as to place the offset portion of said tube entirely within the space customarily provided between said tubular lining and said casing means.

3. In a furnace wall the combination of a wall lining on the heated side of said furnace wall, comprising a plurality of heat absorbing and fluid cooled tubes parallelly disposed generally in the plane of said wall, said tubes being mutually spaced a distance substantially less than the tube diameter, means for forming an access opening in said wall lining, said opening having a width that is at least equal to the distance between two tubes that adjoin a pair of mutually adjacent tubes, said means comprising a first double offset in a portion of a first one of said pair of mutually adjacent tubes and a second double offset in an adjacent portion of the second one of said pair of mutually adjacent tubes, each of said first and second double offsets having a first offset bending each first and second tube in mutually diverging directions away from said plane and away from the heated side of said wall, and a second off-set bending each said first and second tube in mutually converging directions toward and back into said plane, the depth of said offsets being at least sufficient to place the offset portions of said pair of tubes outside of said width when viewed in a direct-ion normal to said one plane, and a bend applied to each of said double offsets in opposite directions, each of said bends following the periphery of an imaginary elongated curved body having a longitudinal axis directed transversely to the directions of said double offsets, the concave sides of said bends facing said Wall lining.

4. In a refractory furnace wall the combination of a wall lining on the heated side of said furnace wall, comprising a plurality of heat absorbing and fluid cooled tubes parallelly disposed generally in the plane of said wall, said tubes being mutually spaced a distance substantially less than the tube diameter and lined on the cool side thereof with casing means, means for forming an access opening in said wall lining, said means comprising a first double offset in a portion of a first one of said tubes and a second double offset in an adjacent portion of a second adjacent one of said tubes, each of said first and second double offsets generally lying in mutually diverging planes forming acute angles with said wall plane and extending in a direction away from said heated side, and a bend applied to each of said double offsets in opposite directions, each of said bends folllotwing the periphery of an imaginary elongated curved body having a longitudinal axis directed transversely to the directions of said double offsets, said axes being outwardly spaced from opposite sides of said opening, said bends being of limited dimensions such as to place the offset portions of said tubes entirely Within the space oustornarily provided between said tubular lining and said casing means.

References Cited by the Examiner UNITED STATES PATENTS 2,011,026 8/1935 Bailey et a1. 122-235 2,025,066 12/1935 Millar 122-235 2,346,715 4/1944 Woodward et al. 122-235 FREDERICK L. MATTESON, JR., Primary Examiner.

KENNETH W. SPRAGUE, Examiner.

Claims

1. IN A FURNACE WALL THE COMBINATION OF A WALL LINING ON THE HEATED SIDE OF SAID FURNACE WALL, COMPRISING A PLURALITY OF HEAT ABSORBING AND FLUID COOLED TUBES PARALLELLY DISPOSED IN ONE PLANE, SAID TUBES BEING MUTUALLY SPACED A DISTANCE SUBSTANTIALLY LESS THAN THE TUBE DIAMETER, MEANS FOR FORMING A WIDTH THAT IS AT LEAST EQUAL TO THE SAID OPENING HAVING A WIDTH THAT IS AT LEAST EQUAL TO THE DISTANCE BETWEEN TWO ALTERNATE TUBES, SAID MEANS COMPRISING A DOUBLE OFFSET IN ONE OF SAID PLURALITY OF TUBES, SAID DOUBLE OFFSET HAVING A FIRST OFFSET BENDING SAID TUBE IN A DIRECTION AWAY FROM THE HEATED SIDE OF SAID WALL AND AWAY FROM THE CENTER OF SAID OPENING, AND A SECOND OFFSET BENDING SAID TUBE IN A DIRECTION TOWARD AND BACK INTO SAID PLANE, THE DEPTH OF SAID OFFSET BEING AT LEAST SUFFICIENT TO PLACE THE OFFSET PORTION OF SAID TUBE OUTSIDE OF SAID WIDTH WHEN VIEWED IN A DIRECTION NORMAL TO SAID ONE PLANE, AND A BEND APPLIED TO SAID DOUBLE OFFSET, SAID BEND FOLLOWING THE PERIPHERY OF AN IMAGINARY BODY OF ROTATION HAVING AN AXIS DIRECTED TRANSVERSELY TO THE DIRECTION OF SAID DOUBLE OFFSET, AND WITH THE CONCAVE SIDE OF SAID BEND FACING SAID ONE PLANE.