# Controlling the flow of powder from a container

I was wondering how you would control the flow of powder from a container (with a small cylindrical dispenser at the bottom).

The container is filled with powder. As the container drains, less pressure will be exerted on the bottom most powder, affecting the flow rate (at least, I think).

Say I select 32.5 grams and hit a button. What process would you use to deliver this measurement of powder from the nozzle?

• Would a lasar work?
• Would there have to be a measurement of the current mass?
• Would you need to know density?

I also posted this on Quora and got a very nice introductory answer but something more specific could help me. Also, I was given a link to the Weisbach equation, but the contents of the container will be a powder. Probably varying in their size and density as some powders will be finer than others. But in general, how would you solve this?

I know the pharmaceutical industry uses expensive equipment to achieve this, but I am not thinking industrial. They are filling tiny little pill capsules with exact proportions. The focus here is household use, with maybe 15–40 g servings

What I am looking to do is input varying size of serving. 20 g, 22.5 g, 35.5 g serving. Optimally, the system will have an electronic motor component, CPU and a valve that opens/closes with use of the motor...

One of my part time jobs is at McDonalds. We have this cream/milk dispensing machine. You input double-double, and out comes 2 creams for the corresponding cup size. I wonder how those work? The paramount different in systems being those dispense liquids, and we're looking to dispense powder solids.

• A worm drive / feed screw / augur allows an approximation to controlled volume feed. Aug 25, 2015 at 15:53