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Steam condensate higher to lower pressure

140 psi steam trap discharging into common header that also receives discharge from 60 psi steam traps. This is a PRV station and is at the beginning of a long condensate run. Traditionally a flash tank used. Spirax/Sarco suggests that a balanced pressure trap for the 140 pressure traps can be used along with a diffuser downstream of these higher pressure steam condensate traps. I am advised by "old timers" to only use "tried trued" flash tank and have not heard of this other concept.

Please advise. Don't want a flash tank.


  • Brad White_9
    Brad White_9 Member Posts: 2,440
    What I have done in the past

    in a PRV setup with multiple stages is to flash the higher pressure condensate into the leg of the next lowest pressure (below the waterline) so it is a defacto flash tank. Just IBT's going from 100-125# range down to 50-60# then 50# flashing to 8-10#.

    I got in trouble once when the lowest pressure leg had too much condensate flashing relative to the summer load so the relief valve tripped.

    My concern with the setup you describe is, can you disipate/absorb the higher pressure (the 140) and not hold back the 60# flow? Do you know your flow rate of 140# HPR?

    Is the vessel at point of entry large enough to be considered a flash tank? Thinking a vertical vessel with the higher pressure releasing below waterline to absorb the flashing.
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