Tuesday 23 December 2008: The other one
Yesterdays Blip was about the start up/standby feedwaterpump.
This Blip is a picture of the main pump, which is actually excactly the same as the startup/standby one.
The only thing that is different between the two is the way they are driven.
The startup/standby one is driven bij an electric motor, this one is driven bij a steam turbine which is a little factory itself.
It consists of a regulating system to control the revolutions (thus effecting the amount of feedwater to the boiler) by admitting more or less steam to the turbine, it has a condenser to convert the used steam into water again.
From here the water is pumped back into the main system and used again as feedwater for the main boiler.
The steam, used by the turbine of the feedwaterpump is branched off from the main steamturbine.
Notice the big isolated pipe on top: this is the main feedwaterline with a big check valve.
The rest of the smaller pipes are used for lubricating oil, cooling water and sealwater because normal stuffing boxes can not be used at these pressures (up to 220 bar).
The supply to this pump is coming from a boosterpump which is at the other side of the steamturbine (so it's at the same shaft).
That's because the difference between the suction pressure out of the feedwatertank in the top of the building and the boiler is too big.
So you need a booster to avoid cavitation.