Try mounting your hopper on load cells and using a load cell sum box/card available from most load cell suppliers, then use a (loss in weight)/(time) algorithim to calculate your rate. Add some intelligence to the system so that it can detect when the hopper has been re-filled.
Daniel:
We have had good luck and fairly good accuracy using a Panametrics XMT868 Flowmeter using transducers that are usable above 500 degrees F. This unit is being used to measure asphalt at about 400 degrees F at the outlet of a Deasphalting unit as it goes to tankage. Metered flow and tank upgauges generally agree within 5% or so.
John A. Beck, III
Control Systems Engineer
Pennzoil-Quaker State Company
Shreveport Refinery
P O Box 3099
Shreveport, LA 71133-3099
(318) 632-4038
(318) 632-4037 FAX
email: [email protected]
Contact Engineering Measurements Company with regards to their HELIX flow meter. (Mr. Saeid Hosseini @ 303-651.0550) They have sucessfully used this meter on bitumin service in Sweden.
Two technologies have been successfully applied to this application, coriolis mass flow meters and ultrasonic time of flight spool piece flow meters. Contact me if you would like more details.