flow rate through an orifice for boiler blowdown

[bethw]

Okay, okay, I give up, I can't seem to locate my chart or formula for the rate of flow through an orifice. It's in our continous blowdown line, the delta P is 90 lbs and the orifice size is 3/8". Can anyone help jog my memory?

 

[steamdog]

This is not a standard orifice flow calculation as you have flashing over the orifice that chokes the flow. One company makes these orifices and has a nice chart, link is below. If it is a larger boiler there may be significant opportunity to save cost by controlling the blowdown rate based on conductivity.