Rotameter Choice 2

[sicktim]

Seems trivial, but I found a cheaper rotameter which has been calibrated and marked with cubic feet of air and I am curious if there is a method to estimate the flowrates of water. Is there a factor to multiply by which depends on the density and viscosity etc? I could just calibrate it, but I don't have it to calibrate and would like to investigate before buying them.

 

[Latexman]

Small water rotameters in McMaster-Carr are only $50.

Good luck,
Latexman

 

[KiwiMace]

I think the relationship is direct linear for the fluid density, however I believe your main problem will be that the float needs to be denser than the fluid or it rises to the top no matter what the flow. An air rotameter will likely have a plastic ball, and the water one a steel ball or conical variation.

 

[jmw]

VA meters are cheap enough.
Why not just buy the right one?

The difference in price will be worth the avoidance of aggravation.
Incidentally, the cheap VA meters are not calibrated, just calibration or quality checked because the scale is moulded into the tube in manufacture.
Look around long enough and you'll find a cheaper one from someone else. Of course, the cost of finding a cheaper one may outweigh the price advantage.
How much time did you spend on this already and how much is your time worth?



JMW

http://www.ViscoAnalyser.com

 

[hacksaw]

usually the float style changes in going from gas to liguid,

having said that all you need is an adjustable valve, a bucket marked in volume units, or a precision scale, and a stop watch

basically calibrate the meter yourself

 

[knapee]

Rotameter usually used in the purge injection station includes a globe valve bypass, block valves, and a blind.

The injection rate is usually controlled by a
fixed orifice to insure a constant supply, even with instrument malfunction.

 

[chemg]

I'm sorry my friend, you need to purchase the water one. The design is so different that any "conversion" will be useless.

I can say that because as operator, I was a lot anger with the people selecting the rotameters. i.e., we have rotameters for crude 47API and when we change it to 30API it was out of range; so imagine if the flow type is different...