- #1
Sherwood Botsford
- 91
- 22
I'm working with tap water. I'm building a fertilizer injection system, and need to control the rate that water flows through the bypass, through the fert tank, and back into the main line.
At small flow values, reynolds numbers are on the non-flat part of the curve, so making something that is even semi-linear is difficult. I've looked at rotameters, but machining a smooth conical bore is beyond my skill
At this point, my best notion is to have a thin leaf of springy material that when flat, meets the opposite wall, but with increasing flow bends to leave a larger opening between the leaf and the opposite wall.
* What to make the leaf out of?
* What shape of chamber makes it possible to easily tell the difference between say 6 l/m and 10 l/m
* Where can I find small valves for the metering?
Pressure across the the metering system is fractions of a PSI. Pressure compared to outside is 30-75 psi.
At small flow values, reynolds numbers are on the non-flat part of the curve, so making something that is even semi-linear is difficult. I've looked at rotameters, but machining a smooth conical bore is beyond my skill
At this point, my best notion is to have a thin leaf of springy material that when flat, meets the opposite wall, but with increasing flow bends to leave a larger opening between the leaf and the opposite wall.
* What to make the leaf out of?
* What shape of chamber makes it possible to easily tell the difference between say 6 l/m and 10 l/m
* Where can I find small valves for the metering?
Pressure across the the metering system is fractions of a PSI. Pressure compared to outside is 30-75 psi.