Thanks to all for suggestions - the load cell would be best way to solve this problem, and was the solution of choice. Unfortunately, the area manager decided that $600 was too much money to spend for instrumentation! He's decided that we don't need to measure that parameter after all...
I've run across an interesting continuous level measurement challenge. I need to measure the level of a mixture of Aluminum Oxide and ceramic powder, inside a closed vessel (approximately 48" high), that is kept under partial vacuum. Ultrasonic sensing is no good, because of vessel not...