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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When there is a positive pressure in the furnace exerting a force outwardly on the furnace walls, this force will be transmitted via the stirrups to the buckstays. The tube walls of the furnace are supported buvkstay the pressure forces developed by positive or negative pressure within the combustion chamber by a plurality of buckstays 10 that extend horizontally around the furnace tube wall at a series of vertically spaced intervals.
In such a buckstay arrangement utilizing 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. An important feature of the invention is that the support plates 42 can be located on the walls 10, 12 at bucksta distance from the corner 14, typically about 10′.
Furnace buckstay design – Combustion Engineering, Inc.
The present invention provides a buckstay drsign 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. Each wall section is comprised of multiple vertically extending tubes 16 which are spaced from and welded to each other by membrane plates 18, welded inbetween adjacent tubes In each case, the plate members 52 and 62 are welded to the end members 44 and 46 of the channel beam 40 at their interfaces therewith.
In the present invention, however, the rods instead of the tubular walls will take the stresses which are being applied to the buckstay assemblies. With the I-beam 40 disposed with its central member 42 horizontal and its end members 44 and 46 vertical, an upwardly facing channel 32 is formed above the central member bucksfay of the beam 40 between the end plates 44 and 46 buckstqy and a downwardly facing channel 34 is formed beneath the central member 42 of the channel beam 40 between the end plates 44 and 46 thereof.
Design of Buckstays | Sulekha Creative
A key aspect of the present bukcstay is the new anchor assembly which provides for more efficient spread of load from one wall section to an adjacent one. Referring to the drawings generally, wherein like numerals designate the same or functionally similar elements throughout the several drawings, and to FIG.
Standoff means in the form of the extended standoffs 26 and support lugs 24 FIG. Alternatively, as shown in FIG. Each pad 46 has the two ends buxkstay a U-shaped plate 48 welded on top to form an aperture Again, one or more support rods 20 would be welded between mounting plates 22 on the furnace tube wall 12 to the outward and upward edge of the U-shaped channel beam 72 to support the dead weight of the box beam An object of the present invention is to provide an improved buckstay arrangement wherein the stresses on the furnace walls will be minimized.
As the furnace expands differentially in a vertical direction, each level of buckstays would move a different amount under the influence of the vertical elongation of the furnace tube walls.
The present invention can reduce or eliminate tube failures in bufkstay membrane-walls due to excessive resign levels caused by start up and cool down temperature induced differential movements between the walls and the boiler buckstay system. Click for automatic bibliography generation. These tube walls are generally supported from the top of the structural framework of the steam generating plant.
However, the present invention would also apply to natural circulation, i. Therefore, it is intended that the present invention be limited in spirit and scope only by the appended claims.
A buckstay system is provided on the outside of the walls 10, 12, and comprises at least one buckstay 20, 22 for each wall section 10, 12, respectively. Referring now to the drawings, and more particularly to FIGS.
US4499860A – Furnace buckstay design – Google Patents
Adjustable buckstay system for vapor generators or the like. As mentioned in the description of FIG. It is thus evident that only the preferred embodiment of the invention has been shown and described and that changes in the construction and arrangement of the parts may be made without departing from the spirit and scope of the invention as claimed.
A buckstay system bucketay a membraned-tube wall of a steam generator having a first wall section which meets a second desihn section at an angle to form a corner.
Steam generating unit having a superheater and reheater each including a radiant section and a convection section. The invention is applied to the walls of furnaces for buckstwy steam generating units wherein the interfaces of the walls defining the combustion or gas chamber include vertically extending aligned tubes through which water is circulated for steam generation.
Two pads are welded to and spaced from each other on top of each support plate, and a U-shaped plate is welded on top of each pad to form an aperture. Therefore, it buckstau 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.
Standoff means in the form of support lugs 24 and extended standoffs 26 are engaged along an inner flange 28 of each buckstay 20, The engagement means can also comprise a pair of clips as shown in sub-illustration FIG. A first extended standoff nearest the corner is welded directly to one tie bar and its upper and lower ends are received within apertures formed by the U-shaped plates.
As previously pointed out the buckstay assemblies desiyn be supported for movement relative to the tubular walls because of the difference in thermal expansion between the members.
A buckstay system according to claim 1, wherein two such anchor assemblies are provided at the corner for each buckstay, one being located above and the other below each buckstay.
US3203376A – Buckstay arrangement for furnace walls – Google Patents
This bow will also appear at the ends of deign 13 and 14 due to the fact that rods 26 will not expand quite as much as walls 15 and The width of the bumper plate 52 is slightly less than the distance between the pads 46 on each upper and lower support plate 42 to provide for relative sliding movement between each pad 46 and the bumper plate 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.
The 10′ distance provides an advantage because the forces can be transferred to the membrane-tube walls 10, 12 at locations where the load can be more efficiently disbursed into the walls. The buckstays are supported or hung on the walls by means of stirrups 19 and The buckstay system of the present invention comprises at least one buckstay 20, 22 for each respective wall section 10, The two associated brackets are connected to each other by stirrup connector means To allow for the differential expansion and yet minimize the difference, the rods are placed directly adjacent the outside of the walls and slidably held against the walls by the retainers The illustrative furnace construction a best shown in FIGS.
These forces tend to bend and buckle the walls as well as put the walls under tension. In a furnace having two pairs of oppositely disposed upright walls joined to define a chamber for containing hot gases, buckstay means extending across 0pposite ones of said walls to form pairs of oppositely disposed buckstay means, means supporting said buckstay means spaced from said walls for movement transversely of said walls, rod means extending from the ends of each of said buckstay means to the corresponding ends of the oppositely disposed buckstay means, said rod means being connected to the respective ends of said buckstay means desogn supported adjacent said walls for movement relative to said walls upon expanding.
These rods are initially adjusted in the cold position with a bend so that at the normal operating temperature they will be substantially straight. A reaction is bucktay created at the ends of each buckstay and tension means must be bukstay to tie together the buckstays on opposite sides of the furnace. For more details about calculation of design buckstay, please look this spreadsheet: When the unit is pressure fired or when any abnormal buckdtay conditions exist, it can be seen that the walls could undergo considerable deflection and buckling if unsupported and that the walls will have considerable pressures exerted thereagainst.
Two tie bars 31 extend out from the corner 14 along each wall 10, 12 and are welded to each other at the corner A brief discussion of the structures to which the present invention is applicable can be had by referring to FIGS. In an alternate embodiment of the present invention, as shown in FIG.