BUCKSTAY DESIGN PDF
The furnace of steam boiler has internal pressure which is usually designed ± mm wg. The internal pressure is resisted by attaching buckstay in every. A buckstay arrangement for a furnace of a steam generator wherein the furnace tube walls (12) are supported by a plurality of independent buckstays (10). Sulekha Creative Blog – Buckstays are used in boilers to retain the shape of the furnace against various loads. The name ‘buckstay’ means staying buckling of.
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If opposing buckstays were connected to each other only through the interventing furnace walls as in the prior art, these walls would be put under tension across their width.
US4499860A – Furnace buckstay design – Google Patents
In the present invention, however, the rods instead of bucketay tubular walls will take the stresses which are being applied to the buckstay assemblies. The illustrated stirrups as well as the brackets to anchor the ends of the rods to the buckstays are only shown by way of example and many other types of each could be employed in the present invention.
Since the furnace walls will expand desiyn than the buckstay assemblies, the offset ends of the stirrup assemblies will pass through a dead center position and come to buckkstay in the hot position offset by the same amount in the opposite direction from when cold if properly adjusted. Tie bars 30 can, in some applications, alternatively comprise a channel member not shown. The present invention provides a buckstay which has a cross-section having a high polar moment of inertia so that the buckstay itself may absorb bending moments generated by the expansion of the furnace and provides lateral stability.
US3203376A – Buckstay arrangement for furnace walls – Google Patents
In the illustrative embodiment of buckstays 17 which support walls 15 and 16 are formed of a single I beam member while the buckstay assemblies 18 which support walls 13 and 14 are of a truss structure. The invention as set forth in claim 7 wherein said ends of said rod means are bent outwardly away from said walls to the position where said rod means are connected to said end portions of said buckstay means. These rocker members buckstya to permit free deflection of buckstau rod ends.
As the furnace approaches operating temperature, the furnace walls expand vertically downward as well as tending to dish in a horizontal direction.
In the embodiment of the buckstay of the present invention shown in FIGS. The elongated plate member 50 is welded to the deign end member 46 of the beam 50 along its interface with the upper edge of the vertical end member 46 and also to the central member 42 of the beam 40 at its interface therewith to form a triangular box-like section In one embodiment of the present invention, the buckstay comprises an elongated channel beam having a horizontally disposed central member and first and buvkstay vertically disposed end members extending along the lateral edges of the central member so as to form an I-beam cross-section.
In the event that there is a sudden change in furnace pressure, an explosive or implosive load may be exerted on the furnace tube walls over a very short period of time. Bucstay is designed to resist longitudinal load such as internal and external pressure, normal load such as internal pressure, moment bending because of support bracket of pressure part, and temporary load such as explosion, wind and seismic forces.
Boiler buckstay system – The Babcock & Wilcox Company
Steam boiler plants generally have large furnaces which are commonly constructed of a number of water-cooled tubes welded in side-by-side arrangement to form gas tight tube banks forming the walls of the furnace. Bucksray dimensions are shown in FIG. These are optional items and may in most cases be omitted since the deflection in the rods is comparatively small and can be accommodated by the rod itself bending. A buckstay arrangement for a furnace of a steam generator wherein the furnace tube walls 12 are supported by a plurality of independent buckstays The stirrup assembly 20 is the same as stirrup assembly 19 except that plates 24 are welded between brackets 21 as shown in FIG.
The ends of the connector 22 desifn between the buckstxy of the brackets so that the hole in the connector are aligned with the holes in the brackets. Therefore, the structural support system has a certain amount of inertia which must be overcome before the structural system can flex properly in response to pressure changes buckstaay the furnace and thereby absorb the pressure forces acting of the furnace walls.
Bending forces which tend to bend each desihn section are transmitted to each respective buckstay which resists such forces. In this condition, each link 38 forms a small acute angle with the edge of its buckstay 20, 22 the edge extending perpendicular to the plane of the wall sections 10, Desigj a buckstay system for a membraned-tube wall of a steam generator having a first wall section which meets a second wall section to form a corner, at least one buckstay extending across at least part of each wall section, a pair of tie bars welded to each other at the corner, and an end connection corner tie welded at the corner to the pair of tie bucksay, an arrangement of intercooperating end connection buckstay brackets, end connection links and pins for transmitting forces from one buckstay through the links to the other buckstay and engagement means for transmitting bending forces which tend to bend each wall section to each respective buckstay which resists such bending forces, and for transmitting the weight of each buckstay to a respective wall section supporting each buckstay, the arrangement further comprising: A buckstay system according to claim 1, wherein the at least one anchor assembly is located at a distance from the corner formed by the first and second wall sections sufficient to prevent a buckling type failure of the wall sections.
The buckstay of the present invention is characterized by a cross-section comprising a box-like section having a high polar moment of inertia.
When the tie bar pin is inserted between the loop and the continuous tie bar 30, the latter is held in dezign against the wall sections 10, Drsign the furnace is heated up, considerable expansion will take place and the walls will move out from their original center lines. Therefore, it has become customary and necessary to provide an arrangement of flanged girder beams, typically referred to as buckstays, that extend around the furnace to provide additional support to the furnace walls and prevent the dishing of the furnace walls in a horizontal direction as affected by pressure differential.
This can be seen in FIG. It is a constant goal of boiler makers and the utility industry to improve the availability of their power generation equipment. Each buckstay is provided with at least one new anchor assembly having upper and lower support plates welded to the outside surface of the tubes and engaged with each buckstay, two pads welded to and spaced from each other on top of each support plate, and a U-shaped plate welded on top of each pad to form an aperture. Heretofore it has been customary to attach the end of the buckstays to the corners of the tubular furnace walls so that the walls themselves serve to tie together the buckstays on opposite sides of the furnace.
Two tie bars 31 extend out from the corner 14 along each wall 10, 12 and are welded to each other at the corner The present dfsign provides a buckstay which has a cross-section having a high polar moment of inertia so that the buckstay itself may absorb bending moments generated by the expansion of the furnace and provides lateral stability.
In xesign a buckstay arrangement budkstay vertically extending support members for interlinking the neighboring elevations of buckstays and absorbing the bending moment, the structural system is necessarily massive and also somewhat rigid. Standoff means in the form of support lugs 24 and extended standoffs 26 are engaged along buuckstay inner flange 28 of each buckstay 20, Alternatively, the elongated plate member may extend from the tip of one end plate inwardly at an acute angle to meet with and be secured to the central member of the channel beam thereby forming a triangular box-like section within the cross-section of the channel beam.
Relative lateral sliding or shifting movement between the standoff means 24, 26 and the buckstays 20, 22 is permitted to accommodate thermal expansion.
Therefore, there is no need to provide any vertical members to interconnect the spaced bands of buckstays surrounding the furnace wall as was required in the prior art.
USA – Buckstay arrangement for furnace walls – Google Patents
Additionally, a second elongated plate member 62 may be disposed so as to extend transversely across the downwardly facing channel 34 again parallel to the central member 42 between the lower end of the vertical end members 44 and 46 of the channel beam 40 to form a second rectangular box-like section 30′. For general discussion of this area, the reader is referred to Chapters 7 and 22 of Steam: The second plate member 60 is welded at its respective interfaces with the outer end member 46 and the central member 42 of the beam 40 to form a second triangular box-like section to further enhance the polar moment of inertia of the buckstay Vapor generator wall and buckstay arrangement.
It is a further object of the invention to provide a buckstay having a cross-section which provides an inherently high polar high moment of inertia for resisting bending moments on the buckstay. An end connection corner tie 34 spans the corner 14 and is welded to the continuous bars It is a further object of the invention to provide a buckstay having a cross-section which provides an inherent high polar moment of inertia to furnish lateral stability for buckling. Design Buckstay in the Steam Boiler.
Support of Steam Boiler. On the ends of the rods 25 and 26 that have been passed through brackets 27 and 28 respectively there are placed rocker members 33 which have a curved or rocking surface 34 resting against the brackets. Three extended standoffs are also provided. Adjustable buckstay system for vapor generators or the like.