METHOD OF MANUFACTURING OF SHAPED FIN PLATES SUITABLE FOR VARYING PITCH BETWEEN INCLINED FLOOR PANELS AND VERTICAL PANELS OF HIGH PRESSURE HIGH TEMPERATURE STEAM GENERATOR
FIELD OF INVENTION:
This invention relates to the method of manufacturing of intermediate panels for High Pressure High Temperature Steam Generators. More particularly the invention relates to the manufacturing of fin plates to suit varying pitch of the intermediate floor panels which are inclined at an angle of range between 12° to 17°.
BACKGROUND OF THE INVENTION:
The High Pressure High Temperature Steam Generators used for power generation comprises of first pass, intermediate pass and second pass. The floor panels are appearing in the intermediate pass.
Normally the panels are made with tubes and fins welded together. If the pitch (the centre distance between the adjacent tubes) is uniform, there will be no difficulty in welding the fins. But in the extended floor panels the pitch is varying between the horizontal and vertical panels (the pitch difference is 3 to 4 mm).
In the existing method, with great difficulties, the fin plates which are made in press brake bending machine are taken to the assembly and by trial and error method, the fin plates are heated up through a flame torch and hammered inside to accommodate the varying pitch.
The time taken for fit-up of these shaped plates used to be approximately 1-2 shifts for one panel by the present method of manufacturing and the accuracy by this method is poor, as it doesn't properly fit into the gap between the tubes and needs to be manually corrected by hammering and hot correction. For one panel assembly, 15 fin plates are required and there are ten such panels for a steam generator. Hence there is a need to manufacture the newly shaped fin plates to suit the varying pitch.

The document US 4794985 discloses finned heat exchanger tubing with varying wall thickness. A heat transfer unit includes an elongate finned tubular element (18) bent in a serpentine pattern with the thickness of the wall of the tubular element (18) made greater at return bend portions (42) than at cross portions (41) either by more shallow cutting of the rib material from which the fins (21-26) are formed at the return bend portions (42) than at the cross portions (41) or by crimping the tubular element (18) at the return bend portions (42) prior to cutting the fins so that portions (31, 31a) of rib material (27-29) from which the fins (21-26) are cut are compressed inwardly on both sides of the tubular element (18) to increase the wall thickness of tube material at the return bend portions (42).
Another document US 8387247 discloses a method for manufacturing heat radiator having plate shaped fins. A gouging tool (5) is introduced at a slope angle theta to form small, low fins (3) at a position shifted inward from an edge (2a) of a surface (2A) of a metal plate (2) having a high coefficient of thermal conductivity; and the small fins (3) are sequentially formed in a plural number at a fixed pitch until a blade section (5a) of the gouging tool (5) reaches a prescribed depth. A fin formation step in which plate-shaped heat-radiating fins (4) are integrally formed upright by the gouging tool (5) is subsequently repeated in sequential manner following formation of the small fins (3), and the heat-radiating fins (4) are continuously formed in a plural number in the metal plate (2). The plurality of small fins (3) and the plurality of heat-radiating fins (4) are connected to the metal plate (2) at the base portions thereof, and scrap is therefore not generated.; Heat-radiating fins of a heat radiator can be formed by a gouging tool without generating scrap.
The document CN 1571147 A discloses radiator fin and manufacturing method. The invention discloses a radiation fin of radiator and its manufacturing method, where the radiator includes a radiation under plate and plural radiation fins; the bottom surface of the radiation under plate contacts a heat source and the top surface of the radiation under plate is formed with plural channels at pre-set depth and width to make plural radiation fins planted in plural grooves, respectively; the radiation fins are different in thickness and the bottom surface of each radiation fin contacting the groove is thicker than each of the other parts.

However there is no patent available similar to the present method of manufacturing of fin plates to suit varying pitch of the intermediate panels for high pressure, high temperature steam generators.
OBJECTS OF THE INVENTION:
It is therefore an object of present invention to manufacture shaped fin plate to suit the varying pitch of the floor panels.
Another object of the invention is to make shaped plate for 15 degree inclined floor panels without hot correction and hammering and to easily fit between the tubes.
SUMMARY OF THE INVENTION
According to the present invention there is provided a fin plate placed between the Top Die (04) and Bottom Die (05) of the Press. When the Top die (04) is pressed downwards it will get seated into the Bottom Die (05) through the two pin holes provided on the Bottom Die (05). When the plate (03) is pressed between the two dies, it takes the shape of a portion of a frustum of a cone to suit the gap between the horizontal and vertical portion of the intermediate panels.
Thus the drawbacks of varying pitch of fin plates as set in the background are eliminated and the fin plates can be easily put into the panels within a very less time, say for an hour. Hence the process is time saving as well as energy saving.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 shows the assembly of vertical and horizontal panels.
Figure 2 shows the closure view of the existing hot corrected and hammered plates.
Figure 3 shows the Press with the fixtures used for making newly shaped fin plate.
Figure 4 shows the detail of the newly manufactured shaped plate
Figure 5 shows the Top Die of the Press
Figure 6 shows the Bottom Die of the Press

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE PRESENT INVENTION
The fin plate (3) is welded in between the tubes connecting the horizontal portion (1) of the inclined floor panel and vertical portion (2) of the inclined floor panel as shown in Figure 1. The pitch variation between the horizontal portion (1) and vertical portion (2) of the inclined floor panel is clearly shown in Figure 2. According to Figure 3, the fin plate (3) is placed between Top Die (4) and Bottom Die (5) of the Press. When the Top die (4) is pressed downwards it will get seated into the Bottom Die (5) through the two pin holes provided on the Bottom Die (5). When the plate (3) is pressed between the two dies, it takes the shape of a portion of a frustum of a cone as shown in Figure 4 to suit the gap between the horizontal and vertical portion of the intermediate panels.

WE CLAIM:

1. The method of manufacturing of the newly shaped fin plates suitable for varying pitch of the inclined floor panels comprising the steps of :
- placing the fin plate (3) between the top die (4) and bottom die (5) ;
- downward pressing of the top die (4) ;
- ensuring the seating of the top die with the bottom die through the two pin holes provided on the bottom die (5) ;
- transforming the fin plate (3) into a plate with desired shape and profile (6) by pressing between the newly made top die (4) and bottom die (5) of the press ;
- obtaining the final shape of the fin plate in the form of a portion of frustum of a
cone.