HP BY PASS WARM UP
METHODS:
(A) Equalising line with orifice
(B) Drain line at upstream side of valve
connected to downstream side of Main
Steam line strainers
Method (A):
This method results in certain amount of loss of
heat energy and increases HP By Pass
downstream temperature and some times causes
problems in proving emergency operation of HP
By Pass.
Method (B):
This method is suitable for short HP By Pass
upstream line
SUGGESTIONS
1)
To effectively warm up Main Steam line it is
preferable to take tap off for HP By Pass near to
strainer or after the strainer similar to LP By
Pass
2)
The lines are to be taken to the higher elevation
. The horizontal portion of the line to be kept as
minimum as possible to prevent condensate
collection in the upstream side of HP By Pass
SUGGESTIONS Contd….
3)
It is preferable to have a drain pot at the
downstream side of individual Hp By Pass
with provision to drain condensate through
level switches
4)
Water collection in the downstream side
orifice plate is expected at Simhadri since the
orifice dia. is more than the pipe size.Such
deviations are to be prevented
60.3 *12.5 (STUB AT BOTTOM OF THE PIPE)
FE
TE
HP BP
VAV
200 MM
CRH
TO MAIN STEAM STRAINER
DOWN STREAM
Nb 50 LINE
DIRT TRAP
MSL
LOCK
OPEN
HP BYPASS WARMUP SCHEME -1
60.3 *12.5 (STUB AT BOTTOM OF THE PIPE)
FE
TE
HP BP
VAV
200 MM
10M min.
Nb 50 LINE
MSL
LOCK
OPEN
CRH
TO TURBINE FLASH TANK
HP BYPASS WARMUP SCHEME -2