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Can anyone tell me how to calculate blowdown time for a 3/4" pipe? I have made calculation having a data for 2" pipe or more.



???What are you talking about???

Do you want to blow down the pressure in a length of pipe to atmospheric pressure?

Do you want to open a valve at one end of a pipe for long enough to completely replace the standing contents of the pipe with fresh ones?

Or do you want to know how long to blow down a boiler connected to its blowdown tank with 3/4" pipe?

Or are you asking what the dwell time in the pipe is for a continuous blowdown line from the boiler to the blowdowns heat exchanger?

Remember: better questions yield better answers.


"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]


Sorry for not clarifying the question much. I am asking that I have a boiler that undergoes intermittent blowdown to maintain required TDS. I want to know how much blow down in terms of time like minutes would be required to achieve required TDS. Like the TDS of boiler water is 4000 ppm. I want to reduce it till 3300 ppm. Then how much minutes would be consumed by a 3" blowdown pipe to achieve this much TDS?

Obviously the calculation involves boiler capacity and pressure. I have done the calculation but the data available was for 2" pipe minimum. I want to know about 3/4" pipe. Hope it will clarify


Such calculations are beyond me, but as a steam plant operator I'd dare say this would typically be determined empirically, viz., the operators would note the before TDS, blow down for a specified and recorded interval, then do the same thing the next day taking into consideration how much and which chemicals have been fed to said boiler in that 24 hour period, and so on, adjusting blowdown time on a rolling basis as needed to achieve the required TDS.


"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

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