Blowdown flow in a power boiler

[Ltrujillo]

Hi!
I have a problem, the measuring of blowdown flow in a power boiler is erratic, the meter is a DP transmitter (0-100"WC @ 0-8 m3/h)with a orifice-plate, I thinking that is not good, the contractor says that the water to this pressure and temperature (1000 psi @ 552°F) is "flashing".

So, anybody knows other form of measuring this current.

Regars

 

[roydm]

At 1000# I assume your meter is after the blowdown valve, have you thought about a vortex meter, they work quite well for steam.
Perhaps describe your installation better, someone here will have done something similar, do you use condensate pots on the orifice installation?
Is the plate before or after the valve?
Attach a sketch if you can.
Roy

 

[ilan7]

Water at 552°F will flash (turn into steam) when pressure is lower then 1050 psi Abs. Means you are not measuring water any more but water with pockets of steam. It might be the reason for the problem.
In order to prevent it - it will be halpfull to keep the pressure a bit higher then the flash point.
Regarding flow measurment, I would try and use V-Cone flow meter - work beter then the Orifice.

http://www.mccrometer.com/products/product_vcone.asp

You can also try the Rosemount Conditioning Orifice Plate

http://www.emersonprocess.com/rosemount/products/flow/conditioning_orifice_technology.html

It says it has beter performace then regular Orifice

ilan

 

[Ltrujillo]

Thanks, I'm going to take their advices.

Roy, It doesn't have condensate pot and it's before the valve