Field of the Invention
Tine Invention relates to standardisation of erection plate attachment sub-assembly for
2nd pass panel of once through super critical (OTSC) boilers. More particularly the present
invention relates to an improved system and method for assembly of 2nd pass panels of once
through super critical (OTSC) boilers by erection plate attachment sub-assembly.
Background of the Invention
Boiler power plant consists of headers, coils, loose tubes, panels and its attachment.
These are all products named with various product group manufacturing assembly (PGMA).
The subject of the invention is about panel and its attachment, which is used for erection
purpose of panels at sites. Around 15 types of panels of PGMA's come under 2nd pass panel
category. These super heater panels consist of tube, fin flat, opening and its plate attachment,
which are fabricated by panel formation machine. Cutting the slot and welding of attachment
in the tube are to be done by manual welding process. Usually all the panels are assembled
butt to butt joint at sites. All these panels are erected at sites with the help of erection plate
attachment assembly. The erection plate attachment gives a proper alignment to erection of
the various panels of PGMA's at sites so the panel tubes can be butt welded easily in a proper
way. If there is any mismatch in the size of erection plate assembly in either end of panels,
the butt joint cannot be performed properly due to improper alignment.
This may happen due to incorrect selection of erection plate assembly, if it is already
welded at manufacturing shop. Previously the erection plate sub-assemblies were released
w.th d,fferent dimensions and different drawing for different pitches of 2nd pass panel. Usually
advance actions were taken for availability of these attachments by sub-contracting 2 to 3
months in advance before panel formation and delivered to store within a month for taking
into stock. After the complete formation of panel, the attachments were to be welded
Therefore it was needed to search and choose the assembly from store to match the
corresponding panel, After getting the same, it had to be ensured that the dimension of
attachment related to that PGMA or not. Sometime it created more confusion to shop and it
was time consuming.

After a detailed study of various PGMA's for varying tube diameter and pitch of different
panels, it was decided to optimize the dimension of erection plate attachment sub-assembly.
The present invention gives a solution to this problem by optimizing a single dimension thus
smoothening the work at shop during panel manufacturing that also ensures proper alignment
for panel butt joints at sites.
Objects of the Invention
The object of the present invention is to ensure an improved system and method for
assembly of 2nd pass panels of once through super critical boilers by erection plate attachment
sub-assembly which has been standardized as a single manufacturing drawing for varieties of
panels.
- Another object of the invention is an improved system and method for assembly of
2nd pass panels of once through super critical boilers by erection plate attachment sub-
assembly which reduces the cycle time eliminating the advance action of mass procurement.
- A further object of the invention is to make it convenient to use a standardized
erection plate attachment sub-assembly for any type 2nd pass panels with any pitches.
- A still another object of the present invention is to ensure easy identification of the
attachment at store for panel manufacturing.
- A further object of the invention is to standardise the erection plate attachment sub-
assembly that ensures proper alignment of panels at site by butt joint.

Summary of the Invention
The erection plate attachment sub-assemblies were studied and arrived at common
dimension to match panel of different dimensions and different pitches. A single drawing can
be released for all the panels. Hence the assembly with panels can be straight away taken up
for use. The present invention relates to an improved system and method for assembly of 2nd
pass panels of once through super critical (OTSC) boilers by erection plate attachment sub-
assembly.
Brief Description of the Accompanying Drawings
Fig 1 shows schematic drawing of bend erection plate
Rg 2 shows the washer plate
Fig 3 shows the erection plate
Fig 4 shows the isometric view of bend erection plate attachment sub-assembly on one
side of panel.
Rg 5 shows complete set of erection plate attachment sub-assembly on either side of
panel.
Detailed Description of the preferred Embodiment of the Invention
As shown in Rg 4, the assembly consists of the following items.
1. Erection plate sub-assembly consists of 2 sets in each fitting.
2. Initially between two no's of erection plate (4) of dimension "6xl52x228"(fig.3) lap joint
with one no bend erection plate (2) of dimension "6x70x235" (fig.1).
3. Weld one no of washer plate (3) of dimension "20x89x291" (fig.2) perpendicular lap
joint on one side arm of bend erection plate (2) which has already been welded with
Erection plate (4). Care is taken that the bottom surface of bend erection plate (2)
matches with the bottom surface of washer plate (3).
4. Make slot in fin flat as shown fig.4 as per erection plate (2) dimension (width), slightly
oversize and insert the partially assembled erection plate attachment sub-assembly.

5. Finally one no of bend erection plate (2) fig.1 and washer plate (3) fig.2 to be tack
welded suitably at other side of the panel at site after panel tube alignment.
Fig.4 indicates: tube (5), fin flat (6), bend erection plate (2), washer plate (3), erection
plate (4), panel pitch (7).
The fig.4 is sample cut out portion of panel, which is fabricated by tube (5) and fin flat
(6). Here at the end of the panel, the erection plate sub-assembly (1) has to be placed.
The slot is to be made in fin flat (6) for placing erection plate sub-assembly (1). The
assembly (1) consists of bend erection plate (2), washer plate (3) and erection plate
(4). And this assemble only has been taken for improvement and implemented in OTSC
boilers.
Advantages of the Invention
The proposed device is of simplified design and permits any outside diameter of the
panel ranging from 44.45mm to 63.5mm.
The development of the device eliminates manufacturing of different size of erection
plate assembly. The assembly can be used for any pitches of the panel. Easy to find out at
store without measuring dimension. It minimises the cost for sub-contracting charges by
taking bulk action. The assembly can be stocked in advance for future boilers. Sites also can
be sent as loose item whenever in urgency if required.


6 different non-standard items has been standardised as a one standard item, with the
size description as given above in SL. No: 2 & 3. Previously according to tube diameter and
panel pitches, the different type of erection plate sub-assembly had been used in panels. On a
detailed study, the new dimension was arrived. Panel tube OD (8): It is diameter of the tube
material.
Panel Pitch (7): Distance between two tube centres in panel or, distance between respective
location points of consecutive tube fin flat.
If W be the width of the bend erection plate (2) of (fig 1) which is standardised as
70mm in dimension 6x70x235mm and T1 be the thickness of erection plate (4), fig 3 which is
standardised as 6mm in dimension 6x152x228mm, then 'W' should be more than maximum
diameter of the tube Dmax. Here the maximum diameter of the tube as per table 1 is 63.5mm.
The width of the bend erection plate (2) has been standardised as 70mm in place of existing
dimension of 46, 47, 49, 57.5 and 64mm which is more than Dmax.
The minimum pitch required from table 1 is 102 mm in serial number (04).
The total width of the bend erection plate (2) including two erection plate (4) = width of bend .
erection plate + 2 x thickness of erection plate = 70+12=82mm.
This is less than the minimum pitch of 102mm. Therefore it is also fulfilling the minimum pitch
requirement.
The length of the washer (3) is also standardised as one in dimension 20x89x291mm which
replaces multiple dimensions 117, 118, 222, 225, 237 and 239mm as was used earlier.

We Claim
1. An improved system and method for assembly of 2nd pass panels of once through super
critical boilers by erection plate attachment sub-assembly (1) comprising:
a bend erection plate (2) formed in the shape of letter U and placed in inverted
position;
a plurality of erection plate (4) abutting in vertical upright position from both the sides
of bend erection plate (2) such that the outer surface of the central base of bend
erection plate (2) is approximately in the middle of erection plate (4) and welded
therein;
a washer plate (3) placed vertically abutting with one arm outer surface of bend
erection plate (2) and welded therein such that the outer surface of central base
surface of bend erection plate lie in the same plane with the bottom surface of washer
plate (3), the dimension of bend erection plate so maintained that W >Dmax, where W is
the width of bend erection plate (2) and Dmax is the maximum tube dia of the panel
where it is to be assembled and
W+2xT1