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Hi friends,

I'm looking for a precise flow sensor or flow meter with any analogue output which can measure a very low flow. The fluid to be measured is a liquid peroxide, which has a density and viscosity similar to water. The maximum flow can be 100 ml per minute. Moreover, the flow is pulsating and the recommended wetted parts can be stainless steel and teflon.

Please comment for a right choice with less maintenance.

Thanx in advance.

Jariz Khan

Have you considered a coriolis (mass) meter? That range is easily accomodated with great accuracy and pulsations can also be attenuated. They are quite expensive, however.

There are numerous manufacturers of small thermal dispersion flow meters, used extensively in the pharmas for metering H2O2.

I believe Sierra Instruments and Kurz both have those cigarette sized flow meters complete with tube fittings.

My recommendations:
A. Coriolis - low maintenance mass flow, Micromotion, Yokogawa, etc.
B. Gear/rotor style PD meter - Litremeter LF15 or similar.

A CMF010M from Micro Motion would likely be a great fit. Accurate (.1% of rate), handle pulsating flows and very low maintenance.

Check out the Siemens Sitrans FC300 DN 4 compact coriolis mass flowmeter
http://pia.khe.siemens.com/index.aspx?nr=7643

You may want to check out a Quantim from Brooks Instrument. It is a coriolis meter that can handle extremely low flow.

Hi Jariz,
You were looking for a “precise flow sensor or flow meter with any analogue output which can measure a very low flow.”

Please correct me if I am wrong, but I supposed you wanted “an accurate flow sensor or flow meter” instead of “a precise flow sensor or flow meter”. Bear in mind that accuracy and precision are not the same thing in instrumentation. An instrument maybe precise but not accurate or accurate but not precise.

Hope this would enlighten you.

EdgarP

I would recommend Capillary Based Thermal Mass Flow Meter which are inexpensive to offer +/-1% of accuracy over full scale if you are looking for much much better accuracy look at Micro Motion Coriolis Flow Meter. Look at McMillan (http://www.mcmflow.com) for Mass Flow Controls (Capillary Based Thermal Mass Flow Meter).

-Rohit

What about a positive displacement flow meter? No problems with pulsations, or the other alternative is to use the pump speed from your positive displacement pump, because I am pretty sure you will be using a positive displacement pump with peroxide with a flow that small.

Chris Jennings

There are lots of good choices for this application, including our own Laminar Flow Element (Series/LFE meter; no moving parts and low cost). However, for any of these meters to work anywhere near their rated accuracy, the question of the pulsating flow needs to be addressed. Both the frequency and amplitude of the pulses is important. Typically what can happen with pulsating flow is the meter will read some RMS or average value rather than the real flow rate. Since you are dealing with relatively low flow, some type of dampener or capacitance in the system will likely smooth out the flow enough to get good results.

Sincerely,
John Catch
www.inflowinc.com

Check the following link:
http://www.sensorsportal.com/HTML/SENSORS/FlowSens_Manuf.htm

FTI (Flow Technology Inc) has a new Ultrasonic meter that is designed for very low flow rates. Might be worth checking with them.