FIELD OF THE INVENTION
The present invention generally relates to manufacturing of headers used in high pressure boilers. The invention particularly relates to a method of bow correction of headers subsequent to welding and heat treatment of stubs on the pipes. More particularly the invention relates to a method for transportation of inserts in a process of bow correction of welded and heat treated headers in high pressure boilers.
BACKGROUND OF THE INVENTION
During manufacturing of components like super heater headers, water wall headers, re-heater headers, economizer headers and ring headers used to deliver steam to a transverse chamber including a number of pipes at different places in the high pressure boilers for power generation, the outside diameter of the header pipes selected in a range from 219.1 millimeter to 864 millimeter with a thickness varying from 32 millimeter to 120 millimeter. The length of the header pipe is in the order of 6 meter to 24 meter. The material grade is of low alloy steels, high alloy steels (grade 91) and carbon steel. During welding of the stubs on the header pipes along the length, the stubs generally get distorted. After this welding headers are to be stress-relieved by putting those in the furnace and heating up to 700 degree Celsius. During this process of stress-relieving, the header also get distorted. The process of correcting this distortion

is called bow correction. This bow correction is to be carried out by placing the header pipe in a goose-neck hydraulic pressing machine. The weight of the header assembly may be from 3 tons to 32 tons depending on the size of the header and hence those headers are transported to the pressing machine for bow correction through electrically operated crane called as EOT crane. To correct the distortion, specially designed and fabricated extension rods are to be clamped to the pressing machine RAM. These extension rods are to be taken from the special fabricated tool stand. The extension rods vary in height, weight and shape to suit the circumference of the header pipe. The pick up of the RAM extension rods from the tool stand and insertion in the press are carried out through the EOT crane. This conventional process takes place a huge cycle time. Moreover, safety of the prior art operation is not full-proof. Damages occur to the extension rods. Hence, it is necessary to find out an alternate method for the easy movement of the extension rods from the tool stand to the pressing machine RAM.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a method for transportation of inserts in a process of bow correction of welded and treated headers in high pressure boilers which eliminates the usage of EOT crane for the extension rod movement from the tool stand to pressing machine RAM.

Another object of the invention is to propose a method for transportation of inserts in a process of bow correction of welded and heat treated headers in high pressure boilers which is enabled to pick up the extension rod from the tool stand automatically.
A further object of the invention is to propose a method for transportation of inserts in a process of bow correction of welded and heat treated headers in high pressure boilers which eases the transportation of the extension rods with less man power to the pressing machine for bow correction.
A still further object of the invention is to propose a method for transportation of inserts in a process of bow correction of welded and heat treated headers in high pressure boilers which allows fixing of the extension rod in the press with less effort and safely of the operator.
SUMMARY OF THE INVENTION
Accordingly there is provided a method for transportation of inserts in a process of bow correction of welded and heat treated headers in high pressure boilers. The apparatus comprises front wheels and rear wheels for the movement including rotation of the apparatus in any direction by means of a manual handle provided at a height for ease of the operator to operate. A suitable rod is selected and picked up from the storage rack, and transported to the pressing machine for bow correction of the header with nipples. The apparatus is moved near the stored rack and the suitable pressing rod so selected is picked up by a

pressing rod holder. The pressing rod holder is made of two halves with a hinge arrangement for locking and unlocking activities. The operator simply unlocks the pressing rod holder so that the selected pressing rod is placed inside the pressing rod holder and locked with a pin (not shown).
Now the holder is moved up vertically by means of operating the handle which is connected to a hydraulic piston movable inside the hydraulic cylinder of the pressing machine. The outward motion of the press rod holder is obtained by moving an extended arm which can slide horizontally inside the fixed arm. 0nce the pressing rod is accommodated by the press rod holder, the whole apparatus is moved by pulling the handle rod to the pressing machine (not shown). The extension rod is moved horizontally to the required position and lifted vertically by operating the handle.
With less effort the press rod is mounted just by unlocking the press rod holder. The apparatus is moved away from the pressing machine so as to ease the bow correction operation. The vertical pillar is connected to the fixed arm by means of the hinge plate assembly. The hydraulic oil tank supply the hydraulic oil through hydraulic hose to the hydraulic cylinder. The apparatus is provided with a counter weight to maintain the centre of gravity by balancing. The hinge rod assembly is used to mount the hydraulic cylinder.
By this process, the time taken is only 45 minutes instead of 4 and ½ hours by the normal method.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figure 1 shows an isometric view of the used for pick up, transportation and mounting of pressing rods in the pressing machine.
Figure 2 shows different types of pressing rods used in the pressing machine.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION
Referring to Figure 1, the apparatus is having front wheel (14) and rear wheels (13) for the movement and rotation of the whole apparatus in any direction by means of manual handle (6) provided at suitable height for ease of the operator to operate. The pressing rod (16) is selected from the stored rack and transported to the pressing machine for bow correction of the long header pipe with nipples. The apparatus is moved near to the stored rack and the suitable pressing rod is selected is picked up by the pressing rod holder (3). The said pressing rod holder (3) is made up by two halves with a hinge arrangement for locking and unlocking activities. The operator simply unlocks the pressing rod holder (3) and the required pressing rod (16) is placed inside the pressing rod holder and locked with a pin (not shown).
Now the holder (3) is moved up vertically by means of operating the handle (15) which is connected to the hydraulic piston (9) moved inside the hydraulic cylinder (10). The outward motion of the press rod holder (3) is obtained by moving the extended arm (2) which can slide horizontally inside the fixed arm

(1). Once the pressing rod (16) is taken by the press rod holder (3), the whole apparatus is moved by pulling the handle rod (6) to the pressing machine (not shown). The extension rod (2) of the machine is moved horizontally to the required position and lifted vertically by operating the handle (15). With less effort the press rod (16) is mounted just by unlocking the press rod holder (3). The apparatus is moved away from the pressing machine so as to ease the bow correction operation. The vertical pillar (5) is connected to the fixed arm (1) by means of a hinge plate assembly (4). The hydraulic oil tank (7) is supplying the hydraulic oil through hydraulic hose (8) to the hydraulic cylinder (10). The device is provided with counter weight (11) to maintain the center of gravity by balancing. The hinge rod assembly (12) is used to mount the hydraulic cylinder.

WE CLAIM :
1. A method in an apparatus for selecting, transporting and inserting a pressing rod into the pressing tool of a pressing machine to do the bow correction of long headers comprising the steps of :
- moving the apparatus near the stored tool stand and selecting a pressing rod,
- picking up the selected pressing rod by a pressing rod holder (3), the said pressing rod holder (3) being made up of two halves with a hinge arrangement for locking and unlocking the pressing rod (16) placed inside the pressing rod holder and locked with a pin (not shown);
- moving and rotating the apparatus having front wheels (14) and rear wheels (13) in required direction by means of a manual handle (6) provided at a suitable height for ease of the operator to operate;
- moving the holder (3) vertically upwardly by means of the operating handle (15) connected to a hydraulic piston (9) movable inside a hydraulic cylinder (10) of the pressing machine, the outward motion of the press rod holder (3) being obtained by moving an extended arm (2) which can slide horizontally inside a fixed arm (1); and

- moving away the device once the pressing rod (16) is accommodated by the press rod holder (3), the device being moved by pulling the handle rod (6) to the pressing machine, wherein the extension rod (2) being moved horizontally o the required position and lifted vertically by operating the handle (15), thereby mounting the press rod (16) by unlocking the press rod holder (3).
2. The device as claimed in claim 1, wherein the vertical pillar (5) is connected to the fixed arm (1) by means of a hinge plate assembly (4), wherein the hydraulic oil tank (7) supplying the hydraulic oil through a hydraulic hose (8) to the hydraulic cylinder (10), wherein the apparatus is provided with a counter weight (11) to maintain the center of gravity by balancing and wherein the hinge rod assembly (12) is used to mount the hydraulic cylinder.