OT: Metered Powder Output Sense

I am working on an experimental system for a new chemical a supplier of a client of mine has invented and my customer is going to be their Guinea Pig.

The chemical needs replenished based on Amp/Hours applied by 2 rectifier power supplies. But the replenish is not a chemical metering pump I can control the pulses and check for flow out of the pump - it will be a dry powder added 148 grams each replenish.

The control will be run an auger motor for x.xx seconds to get the precise amount of powder. OK with me so far.

My issue is there isn't any monitoring of output to ensure the powder is actually dropping into the tank. The amount is about 5 ounces, so I was thinking drop the powder into a scoop or trough that trips a switch at over 4 ounces, then after the auger stops dump the trough. Not 4 ounces means drive failure, powder bin empty, fuse blown, etc. - set an alarm.

Has anyone ever used a monitoring system similar to this and know who has them? Or am I going to have to design one myself? I don't want to just run it and at the end of the day find out the system wasn't working.

Not an answer. Perhaps a starting point. Volumetric auger filler

Yeah most powder mixing systems I have seen they just assume the powder is getting through or have been adding the powder manually in one tank and using a transfer pump to move it over to the distribution system tank.

I do like where your head is at though, weighing it seems like a logical solution.

I set up a recipe and control system at a factory that mixed and packaged dry baking mixes, and they used weight as well. I think that's the easiest & most accurate method when dealing with powders.

Doug,

That looks like a nice dispenser, but the chemical maker is supplying the dispenser for their powder. And for measuring they hand place the cup on a scale.

Doug-P said:

Not an answer. Perhaps a starting point. Volumetric auger filler

Click to expand...

Link has a double HTTP - didn't work with my browser.

Corrected link.

I would use a scoopwheel, it will give you a pulse every 10 grams,

Is the powder going into a liquid? Is there anyway to instead makeup a higher concentration liquid manually and use that as feedstock to the process?

Shooter,
That was my question to the chemical engineer, I could scoop the exact amount and make sure the scoop cycled by proxy or encoder, but he said it's the dispensing system they use - and it's a lock.

g,
This customer does have a lot of "day tanks' for other lines they fill in the morning and meter out as needed, but for some reason that is not an option with this powder per the chemical engineer.

Would it be possible to put either the powder hopper or the tank on load cells and do a loss/gain in weight?

So they already have the dispenser system that they say you must use? You are just trying to devise a way to verify?

We had a system that we developed that would meter dry powder into a liquid. The system never worked correctly as the dry powder was not very repeatable per rotation of a n auger. Also, the power would stick to the funnel/shoot leading into the tank due to liquid splashing out etc. Tons of time was wasted on this effort until we finally replaced it with a "concentrate" tank that had an overly strong mixture. This worked much much better.

i was thinking it as a verifying instrument, not to replace the original.

JaxGTO:
That may be possible, but 50# of powder and the weight of the assembly, then trying to make sure it lowers at least 140 grams might be asking for a lot, Maybe?

g.,
Found the reason they say they can't have a day-tank and meter in concentrate - they can't add any more fluid to the tank as it would need to be drained off and this waste would need heavily treated to be able to dispose of, at a prohibitive cost. And the reasons you stated are the reasons I want to make sure the minimum quantity of powder is dispensed every call - if there is more it will be OK to have a stronger solution, just a waste of powder.

Aabeck said:

...but 50# of powder and the weight of the assembly, then trying to make sure it lowers at least 140 grams might be asking for a lot...

Click to expand...

140 grams = .3 pounds.
I could go 2 decimal places with 100 pound load cells if I knew there wasn't any vibration during measurement. If it's noisy, then I need time to take several readings and average.

keithkyil,

That does sound like it would work, I'll pass that suggestion on tomorrow. And in the long run it might be less expensive than making a trough to catch, weigh and dump.