FIELD OF INVENTION:
The invention relates to a method of grinding the piping joints used in high pressure boilers. More particularly the invention relates to a flexible/portable device used for grinding the welded joint.
BACKGROUND OF THE INVENTION & PRIOR ARTS:
High pressure boilers and industrial boilers are having number of pipes and headers. The header pipes are welded by conventional welding process. After the completion of welding the excess material are to be ground before ultrasonic test to check the quality of the weld. For this operation the weld assembly is placed over the ‘v’ block and surface grinding operation is carried out by hand grinding machine. To get clean surface the buffing wheel is used to further finishing. For this operation crane is required to rotate the job after completion of one segment. Rotation is necessary for segment to segment completion. Since number of butt joints are more and diameter of header pipe (Ø219.1mm outside diameter to Ø711mm outside diameter) is varying it is time consuming process and causes fatigue to the operator and hence the quality gets affected. Hence there is a need to modify the grinding machine with developed apparatus.

OBJECTS OF THE INVENTION:
The object of the invention therefore is to develop a novel device of grinding an irregular surface of welding.
Another object of the invention is to grind the surface by emery belt.
Further object of the invention is to grind linearly and axially by feed mechanism.
Yet another objection of the invention is to reduce machining time.
SUMMARY OF THE INVENTION:
The invention relates to development of one portable grinding device to the used for grinding irregular welded surface of butt joints.
According to the invention, the grinding machine is placed on its position in such a way that centerline of the work piece and centerline of the driven wheel are in the same axis. In a prevailing condition, the length of the weld joint is 80mm and the machining is required 150 mm extra on the either side of the joint with respect to centerline of the weld joint. This longitudinal movement is carried out through liner adjusting handle. The counter weight is placed at the center of the bracket assembly and the roller provided in counter weight will maintain the tension

in the grinding belt. The motor with driving wheel is placed over the machine base. The machine base is a heavy structure to prevent any vibration. Emery belt safety guard is fixed over the driving and driver wheel to safeguard the operator. The motor is placed inside a frame. The motor with driving wheel is placed over the machine base with frame to ease the longitudinal movement.
High pressure boilers and industrial boilers are having number of pipes and headers. The headers pipes are welded by conventional welding process. The weldment is subjected to ultrasonic testing which needed surface grinding to get desire surface finish. Since the number of joints are more per boiler and the time consuming is also high. To avoid this a portable device is developed with emery belt attached to it having longitudinal motion as well as feed mechanism to get the desired surface finish with less time and thereby substantial saving in time and the productivity is increased. The range of outside diameter of the tube varies between 219.1 mm to 711mm.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Fig 1: The schematic drawing showing all the components assembled to perform
Fig 2: Counter weight assembly use to emery belt required tension
Fig 3: Emery belt use to grind the weld joint and driving wheel with driven connecting purpose

Fig 4: Motor with belt used for driving wheel rotation
Fig 5: Linear adjustment handle use to move the motor frame assembly in
linear motion
Fig 6: Feed adjustment handle use to move the motor frame assembly in
horizontal motion
Fig 7: Machine base with stand
Fig 8: Motor frame to place the motor
Fig 9: Bracket assembly connected to driven wheel and motor assembly
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION
Fig.1 depicts a portable surface grinder having a motor (04), a pair of driving/driven wheel (01), one connected to the motor (04) by a V-belt and the other attached to the work piece (12) meant for grinding. The pair of driven wheel (01) is connected to each other through a grinding emery belt (03). The portable grinding machine is taken near the work piece and adjusted by the feed handle (06) and the adjusting handle (05) in vertical and longitudinal directions so that centerline of the work piece (12) and the centre line of the driven wheel are in the same axis. The counter weight (02) placed at the centre of the bracket assembly (09) and the roller provided in the counter weight maintains the tension of the grinding belt (03). The motor with the driving wheel (04) is placed over the base (07) and grouted strongly

to avoid any vibration. Emery belt safety guard (10) is fixed over the driving and driven wheel (01) to safeguard the operator. The motor is placed inside the frame (08) to avoid any external shock.

WE CLAIM
1) A portable device for grinding irregular welded butt joints comprising ,
a) a motor (04) with a shaft
b) a pair of driving/ driven wheel (01)
c) grinding emery belt (03), connecting the driving/driven wheel (01)
d) feeding handle (06), adjusting vertical movement of the machine towards the work piece (12)
e) adjusting handle (05), controlling longitudinal movement of the machine towards the work piece (12)
f) counter weight (02) placed at the centre of the bracket assembly (09) maintaining the tension of the grinding belt (03)
g) base (07) to hold strongly the motor (04) along with the driving wheel (04)
h) emery belt safety guard (10), fixed over the driving/driven wheel pair to safeguard the operator
i) frame (08) to house motor (04) avoiding any external shock.
2) The device as claimed in claim 1, wherein the motor (04) with the shaft, housed
within a frame (08), powered through the switch (11), rotates the driving wheel
(01) through V-belt connection

3) The device as claimed in claim 1, wherein, a pair of driving/driven wheel (01) holding the emery grinding belt (03) tightly to grind the work piece (12).
4) The device as claimed in claim 1, wherein, grinding emery belt (03) grinds the welded surface of the work piece through rotational movement
5) The device as claimed in claim 1, wherein, the feed handle (06), controlling the movement of the machine vertically towards the work piece (12)
6) The device as claimed in claim 1, wherein, the adjusting handle (05), controlling the longitudinal movement of the machine towards the work piece (12)
7) The device as claimed in claim 1, wherein, the counterweight (02) along with a roller, placed at the centre of the bracket assembly (09) maintains the tension of the grinding belt (03)
8) The device as claimed in claim 1, wherein, the emery belt safety guard (10), fixed over the driving /driven wheel (01) to safeguard the operator.
9) The device as claimed in claim 1, wherein, the base (07), a heavy structure strongly holding the motor and driving wheel to avoid any vibration.

10) A method to grind an irregular surface of welded butt joints through rotation of the grinding emery belt (03), placed on the rotating wheel pair (01), by positioning the portable machine vertically and longitudinally in a position, through control by the feed handle (06) and adjusting handle (05), so that the centerline of the work piece (12) and the centerline of the driven wheel (01) lies in the same axis.