The present invention relates to a method of installing furnace walls of a boiler, more specifically a method of installing a furnace wall of a boiler suitable for constructing a large-scale boiler such as one for a thermal power plan.
Accordingly, in a general construction process for the construction of the boiler furnace wall 2 and the convection pass wall 7, the large beam 8 is attached on top of the established boiler frame that is as high as 60 to 100 meters. After that, by hanging various parts for constructing the boiler furnace wall 2 and the convection pass wall 7 from the large beam 8, those walls are assembled from the upper portion toward lower portion in sequence. However, this construction process does not have high operating efficiency because of the dangerous operation in high altitude. Especially, as the boiler furnace wall 2 has a shape with large length in the lengthwise direction, with the process of constructing from upper portion toward lower portion, the necessary period for the installation work becomes long since the lower portion can not be assembled until the upper portion is assembled. Therefore, the largest factor to prolong the entire construction period for the boiler facility was the installation work for the boiler furnace wall 2.
In order to alleviate the problem, Japanese patent laid-open publication H5-240405 discloses a boiler furnace wall installation method dividing the boiler furnace wall 2 into three portions of an upper portion of boiler proper, left and right lower portions of boiler proper, suspending the upper portion of boiler proper to the desired position after assembling each portion at the bottom position inside of the boiler frame, then connecting the left and right lower portions of boiler proper by translating them to the upper portion of boiler proper. With this method, the construction period is expected to be shortened since there is less operation in high altitude and the upper portion of boiler proper and the lower portions of boiler proper can be assembled in parallel.
However, the method disclosed requires a large space in the boiler frame premise for assembling the upper and lower portions of boiler proper since the operation takes place at the bottom position inside of the boiler frame, which introduces large restriction to the establishment of the boiler frame. Additionally, as the upper and lower portions of boiler proper are assembled in suspension in the same way as the conventional method, a dedicated temporary suspension mechanism for each portion of boiler proper is required.
The objective of the invention is to provide method of installing a boiler furnace walls that can drastically reduce the installation period for the boiler furnace walls, without causing special restriction when establishing the boiler frame, and without the dedicated temporary suspension mechanism.
In order to achieve the objective, the installation method of the boiler furnace wall according to the present invention is a boiler furnace wall installation method with the upper portion of boiler proper and the lower portion of boiler proper, that assembles the upper portion of boiler proper while it is suspended from the top girder module deployed in the boiler frame. At the same time, four faces of furnace water wall panels that constitute the lower portions of boiler proper are pre-assembled on the ground. Upon the completion of each face of the furnace water wall panels, this unit is brought in to the boiler frame premise and lifted toward the upper portion of boiler proper, and upper ends of each face of the furnace water wall panels are connected to lower ends of the upper portion of boiler proper.
With the installation method of a boiler furnace wall according to the present invention, the furnace water wall panel with four faces that constitute the lower portion of boiler proper can be pre-assembled at the more convenient location with safe and efficient operation. In addition to that, the installation period for the boiler furnace wall can be shortened drastically due to the reasons that there is no special restriction to the establishment of the boiler frame, there is no need to make a dedicated temporary suspension mechanism, and the upper and lower portions of boiler proper can be assembled in parallel.
The method of installing the boiler furnace walls according to the present invention is a boiler furnace wall installation method with the upper portion of boiler proper and the lower portion of boiler proper that assembles the upper portion of boiler proper while it is suspended from the top girder module deployed in the boiler frame. At the same time, four faces of furnace water wall panels that constitute lower portions of boiler proper are pre-assembled on the ground. Upon the completion of each face of the furnace water wall panels, this unit is brought in to the boiler frame premise and lifted toward the upper portion of boiler proper, and upper ends of each face of the furnace water wall panels are connected to lower ends of the upper portion of boiler proper. And the furnace water wall panel with four faces that constitute the lower portion of boiler proper can be pre-assembled at the more convenient location with safe and efficient operation. In addition to that, the installation period for the boiler furnace wall can be shortened drastically due to the reasons that there is no special restriction to the establishment of the boiler frame, there is no need to make a dedicated temporary suspension mechanism, and the upper and lower portions of boiler proper can be assembled in parallel.
It should be born in mind other variation of the present invention is achieved by following sequence: After temporarily suspending two sides (left and right) of furnace water wall panels that are the parts of the lower portion of boiler proper, the upper portion of boiler proper is assembled while it is suspended from a top girder module located on the top of a boiler frame, after that, a furnace rear wall and a furnace front wall that are the parts of the lower portion of boiler proper are suspended while the temporarily suspended left and right furnace water wall panel are shifted to the designated position, and the upper ends of the furnace water walls forming four faces are connected to the lower ends of the upper portion of boiler proper. By doing this way, the left and right furnace water wall panels are temporarily suspended in advance, the left and right furnace water wall panels are shifted to the designated position when the connection with the upper portion of boiler proper becomes possible, and each face of the upper end of the furnace water wall panels is connected with each lower end of the upper portion of boiler proper. Therefore the unwanted interference is avoided even in case that the upper portion of boiler proper is assembled in advance and the upper portion of boiler proper itself usually becomes the obstacle when lifting the two (left and right) furnace water wall panels.
It is also desirable to assemble the accompanying buckstay and wind box together as one body, when each of the furnace water wall panels are pre-assembled. By doing this way, the buckstay and the wind box are assembled in the location with a good workability on the ground safely and efficiently. Additionally, the deflection and stress caused to the furnace water wall panels in the process of lifting them will be minimized because the attached buckstay and the wind box increase the rigidity of the furnace water wall panels significantly.
Furthermore, the present invention is characterized in that lifting jacks are located on the top of the boiler frame, and each of the furnace water wall panels are pulled up while the upper portions of furnace water wall panels are pulled by the lifting jacks and the lower portions are dragged on the ground. In this case, it is desirable to pull up the pendant coil to be placed immediately above the furnace rear wall with the lifting jacks mentioned above at the same time. When each of the pre-assembled furnace water wall panels is lifted, the lifting jacks located on the top of the boiler frame can be utilized. Therefore, the safety and efficient operation is achieved for pulling and lifting the huge (several hundred tons) furnace water wall panel blocks to be positioned in their designated position easily.
When the furnace rear wall is lifted, the pendant coil to be located immediately above the furnace rear wall is pulled up with the lifting jacks. Therefore, the installation operation of the pendant coil is achieved efficiently at the same time.
The embodiment relating to the method of installing boiler furnace walls according to the present invention will be explained together with the drawings attached.
The boiler furnace walls 20 surrounded by a chain double-dashed line in
For your information, each of furnace water wall panels such as the roof wall 32, the side wall portions 34 and the lower portion of boiler proper 40 is formed with rectangular water wall panels that have 2-3 meters of side width by welding connection. The boiler furnace wall 20 is configured by connecting the lower end of the side wall portions 34 of the upper portion of boiler proper 30 and the upper end of each furnace water wall panels of the lower portion of boiler proper 40.
In this preferred embodiment, the upper portion of boiler proper 30 in the boiler furnace wall 20 is assembled while it is suspended from the top girder module 28. In other words, after lifting the roof wall 32 with the multiple of suspension parts 56 suspended from the top girder module 28, the side wall portions 34 and internal components (not shown) are assembled sequentially while they are suspended.
At the same time, each of four face furnace water wall panels are pre-assembled on the ground respectively for forming the lower portion of boiler proper 40.
As for furnace hopper front and rear walls 52 and 54 to be connected to the furnace front wall 42 and furnace rear wall 44, the furnace water wall panel with buckstay 60B to be attached are formed as a one body part.
In an ordinary large-scale boiler, a pendant coil 78 that is an internal component of the upper portion of boiler proper 30 is located immediately above the furnace rear wall 44. Therefore, in this embodiment, the construction method of more efficient installation operation is employed by pulling up the pendant coil 78 and the furnace rear wall 44 at the same time. In this method, the upper balance beam 76 is suspended by the sling rods 74 suspended from each center-hole system lifting jack 72. The pendant coil 78 is lifted together by a bolt connection device (not shown) connecting the coil to the upper hugging balance 76. From the upper balance beam 76, multiple of sling bolts 80 are hanging through the pendant coil 78 by selecting its gaps; and a lower balance beam 82 is attached to the end of the sling bolts 80. The furnace rear wall 44 is suspended from the lower balance beam 82 with a hinge device (not shown). By forming a lifting mechanism like this, the pendant coil 78 whose weight is approximately 1,000 tons and the furnace rear wall 44 whose weight is approximately 350 tons are lifted together then installed to the designated positions respectively.
As explained above, the boiler furnace wall installation method according to the embodiment, the upper portion of boiler proper 30 is assembled while suspended from the top girder module 28 located on the top of the center portion 12 of the boiler frame, while the four faces of furnace water wall panels 48, 48, 44 and 42 are pre-assembled on the ground and pulled up, and the upper end of each of the furnace water wall panel is connected with the lower end of the lower portion of boiler proper. Therefore, the assembly of each furnace water wall panels 48, 48, 44 and 42 are conducted on the high workability place on the ground safely and efficiently. Additionally, there is no special restriction while constructing the boiler frame; there is no need to utilize the dedicated temporary lifting mechanism; and drastically reduce the installation work time due to the simultaneous assembly of the upper portion of boiler proper 30, the furnace rear wall 44 and furnace front wall 42 and so on.
Among the furnace water wall panels, two faces of left and right furnace water wall panels 48 is suspended temporarily in advance, the two faces of left and right furnace water wall panels 48 are moved to the designated positions when the connection with the upper portion of boiler proper 30 become possible, and connection of upper end of each face of the furnace water wall panels with the lower end of the upper portion of boiler proper is conduced. Therefore, the unwanted interference is avoided even in case that the upper portion of boiler proper 30 is assembled in advance and the upper portion of boiler proper itself 30 usually becomes the obstacle when lifting the two (left and right) furnace water wall panels.
Additionally, in assembling the furnace water wall panels 48, 48, 44 and 42, the buckstays 60 and 60 A together with the wind boxes 46 are assembled together, so the attachment of the buckstays 60 and the wind boxes 46 can be done at the high workability location on the ground safely and efficiently. It should also be noted that the buckstay 60 and 60A or the wind boxes 46 significantly increase the rigidity of the furnace water wall panels; therefore the deflections and stresses caused in the furnace water wall panels 48, 48, 44 and 42 by lifting the pre-assembled furnace water walls are minimized.
Furthermore, the lifting jacks 18A and 18B equipped on the top of the boiler frame are utilized for lifting the pre-assembled furnace front walls 42 and furnace rear wall 44, the gigantic furnace water wall panel blocks weigh several hundred tons can be pulled up to the desired location easily, which the safety of operation and the efficiency are obtained.
Moreover, since the pendant coil 78 to be positioned immediately above the furnace rear wall is pulled up together with the furnace rear wall 44 with the 12 center hole system lifting jack 72 at the same time, the efficient installation operation of the pendant coil 78 is achieved.
The above preferred embodiment is explained as an installation method including the steps of suspending a pair of left and right furnace water wall panels 48 temporarily in advance, assembling the upper portion of boiler proper 30 while suspended from the top girder module located on the top of the boiler frame, suspending the furnace rear wall 44 and furnace front wall 42 one by one, moving the temporarily suspended left and right furnace water wall panels 48 to the designated position, and connecting the upper end of the each face of the furnace water wall panel and the lower end of the upper portion of boiler proper. However, the present invention is not limited to the installation method disclosed in the embodiment. For example, it includes the method of assembling the upper portion of boiler proper 30 in advance, then lifting the four faces of the furnace water wall panels pre-assembled on the ground, and connecting the upper end of each face of the furnace water wall panel and the lower end of the upper portion of boiler proper.
While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.
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