Low Flow Meters

[woohah]

I'm looking for a way to measure low flow, range 100-1000 cm^3 / hour (0.02-0.2 gallon/hour). The application is chemical dispensing where the chemical will be diluted in 10's or 100's of ppm, hence small flows. I've had limited success finding flow meter technologies that have such a low detection range, but I suspect they exist.

Any suggestions, either on general classes of meters or specific products/manufacturers?

Thanks!
--Woohah

 

[mjh127]

A gravimetrical method will be most accurate. Weigh the storage vessel that is being emptied.

 

[Mrepp]

I've been this route before and know of the two possibilities for technologies to measure the flow. If your fluid properties do not change, mainly heat capacity, doesn't change then FCI and Rheotherm make a low flow meter based on the temperature difference of a reference cell and the process cell q=MCpDeltaT concept.

Otherwise you have to go with a mechanical flow device. Here it makes a big difference in how many players you can choose from if your operating pressures are high. The main keyword search is "nutating disc".

The last big factor is accuracy. If there isn't a high degree necessary you can totalize chem pump pd cycles to estimate the rate to a fair degree of accuracy

 

[buzzie]

How about a straight-forward chemical metering (or dosing) pump. Many varieties and levels of quality available. Precision dosing of chemicals unless it has to a continuous flow should be easy with these devices and calibration can be verified regularly with a calibration column draw-down.

 

[phex]

to get info about flow rates this low, try asking lab equipment manufacturers. those people always deal with this kind of problem, so they will have an appropriate solution, i'm sure.

hth,
chris

 

[Mrepp]

Woohah-

DEA engineering,

http://deaengineering.com/,

makes a good mechanical type meter that is accurate, rated for high pressures, and cheap.