THIS PRESENTATION IS OF BOILERS WHICH ARE ABOVE 500 MW AND WHOSE DOWN COMERS ARE PRESENT ONLY ON THE FRONT SIDE. THE INSIDE PART OF A RING HEADER IS ALWAYS A MYSTERY TO THE OUTSIDERS.IN THESE SLIDES SEE HOW ARE TUBES PRESENT INSIDE THE HEADER WHICH IS RARE TO SEE FOR ANYONE EVEN THOUGH HE IS WORKING IN A BOILER OR A POWER PLANT.

1. P.Harish Babu
A.E (Mechanical)
H.N.P.C.L, Palavalasa,
VISAKHAPATNAM.
Mobile :8106890404

2. Introduction
 For uniform flow of water to all sides
of the ring header we use orifices in
the bottom ring header.As the down
comers are positioned in the front
side of the Boiler only that side of the
ring header may receive more
amount of water leaving other tubes
to starve. So orifices are used.

3.  No of tubes on each side in our ring header
 LHS - 212
 RHS - 212
 FRONT SIDE - 319
 REAR SIDE - 319
 TOTAL -1062

4.  Parts required for fixing of orifices in the ring
header
 Tubes with protruding studs.
 Orifice plates with holes matching the
studs
 Marman couplings with nut and bolt.

5.  Procedure to fix Marman Couplings
 All the tubes in the ring header are housed
inside the perforated trays and these perforated
trays are bolted to the studs protruding from
the inner wall of the ring header.
 In order to fix Marman couplings these trays
have to be removed , stored with proper care
and then re-fix as usual when the fixing of
Marman couplings is completed.

6. Original shape of the tube for fixing the
orifice. The 3 studs projecting out are
different for different DU Numbers.

7. Orifice plate
with holes.

8. Nut and bolt
Marman
coupling

9. Stud protruding from
inner wall of the header
to accommodate
perforated trays

10. Fixed Marman couplings
inside the ring header

11. Perfectly fixed Marman coupling
Nut and bolt are tight.
3 studs are clearly seen out protruding
after fixing of orifice plate.
Uniform gap is seen all over .

12. Checking of tightness of
Marman coupling.

13. Inside the bottom
ring header

14. THANK YOU