Metering Lumpy Reagents

Gents

Does anyone know a good metering system for metering lumpy but thin aqueous reagents (SIBX solution - fairly saturated and with some contamination)
Peristaltics wont work with this liquid as has been found out on countless occasions.
The current system is by gravity and uses a constant level header tank feeding FCV and magflow with PID control. Desired flow rate is 0.1 - 4 lpm. Only a relatively low (approx 2m) head is available across the FCV and magflow, so accuracy is poor and the things block up all the time.
I want to keep the system head as low as possible as blockages are inevitable, so cleaning out on the run is almost inevitable. Have tried pulsed solenoid valves, but have not been able to measure the flow with sufficient accuracy.
Has anyone seen a metering system that might cope with this sort of liquid? I was thinking of some sort of positive displacement device like is used on centralised industrial greasing systems, but suspect it would block up in an eyeblink. I still like the solenoid valves but cant find a compatible (low head, low blockage tendency) flow measuring system. An accurate and reliable flow indicating system has economic benefits in this instance.
All suggestions welcome.

Cheers

Steve Received on Wed Feb 13 06:23:00 2008