Pumping sand and powder

Hi,

Does anyone knows of any motorized pump (similar to a peristaltic one or not) that is able to move sand and/or powder along a 8mm tube, in a similar fashion as a liquid?

The load is quite low and the speed does not matter. The sand to be pumped is very refined and similar to a powder consistency.

Thanks!

I use pressurized air for this purpose (moving abrasive grit from the collection hopper in the bottom of my sandblasting cabinet back to the pressure pot so it can be reused).

The hopper funnels the grit into a tank (I'm using a pressure pot for this purpose). When that tank is full I close a large ball valve at the top of the tank and open an air valve to pressurize the tank to ~20 PSI. There is a hole in the bottom of the pot connected to a 3/8" ID hose that runs to my other pressure pot. The compressed air pushes all the grit through the hose as nice as you please. It's a huge improvement from when I used to manually transfer the grit with a bucket and works really reliably as long as the grit is dry (which it needs to be anyway).

I realize this is not exactly what you're going for but it's definitely something to consider. Other than gravity, I can't think of any other method of moving sand and powder through a tube. If you're talking about a larger diameter tube then you could have an auger drive in it but that's likely to be relatively difficult and expensive. Definitely worth looking at how this sort of thing is done in industry. You can usually find great videos of any industrial process on YouTube and watch them to get some ideas.

pert:
I use pressurized air for this purpose (moving abrasive grit from the collection hopper in the bottom of my sandblasting cabinet back to the pressure pot so it can be reused).

Absolutely correct. Have in mind also that the product you mention is used to remove rust and/or clean industrial machinery surface (for restoring purposes, mainly). Moving this is one of the most abrasive manoeuvres you can imagine, so the pipe has to be either very thick and/or treated by any method in the inside ...

Regards

I'm using silicon carbide. Extremely abrasive stuff. The sandblasting equipment requires much more maintenance than I expected when I bought it. When something breaks down, fixing it usually involves me cleaning up a big mess of spilled grit. I've made a lot of custom modifications to the system over the years (including this pumping system) which makes it easier to work with. I'm actually just using regular braid reinforced air hose for the line between the two pressure pots and have had no problems with any parts along that path wearing through.

The line from the pressure pot to the blasting nozzle needs to be more flexible and also is exposed to a lean mix of grit+air at up to 60 PSI so I had to hunt down some very abrasive resistant tubing for that purpose and even so it regularly wears through. I enclosed the length of that hose which is outside the cabinet and added a pressure sensor with flashing light and buzzer (Arduino controlled of course) that goes off when the hose gets a leak so I can catch it before it makes a mess.

I'm actually using the sandblaster for carving designs on my blown glass work.

pert:
I'm using silicon carbide. Extremely abrasive stuff. The sandblasting equipment requires much more maintenance than I expected when I bought it. When something breaks down, fixing it usually involves me cleaning up a big mess of spilled grit. I've made a lot of custom modifications to the system over the years (including this pumping system) which makes it easier to work with. I'm actually just using regular braid reinforced air hose for the line between the two pressure pots and have had no problems with any parts along that path wearing through.

The line from the pressure pot to the blasting nozzle needs to be more flexible and also is exposed to a lean mix of grit+air at up to 60 PSI so I had to hunt down some very abrasive resistant tubing for that purpose and even so it regularly wears through. I enclosed the length of that hose which is outside the cabinet and added a pressure sensor with flashing light and buzzer (Arduino controlled of course) that goes off when the hose gets a leak so I can catch it before it makes a mess.

I'm actually using the sandblaster for carving designs on my blown glass work.

In fact my comment was for the OP ...

I'm engineer, and used sand to restore industrial steel made machinery .Guess that is glass is even harder to treat ...

Regards

pert:
I use pressurized air for this purpose (moving abrasive grit from the collection hopper in the bottom of my sandblasting cabinet back to the pressure pot so it can be reused).

Thank you a lot Shannon for the reply and good ideas.

Do you have any indication to a small-scale air compressor that I could use for such purpose?

Also: your solution implies that both containers are fully enclosed in order to be pressurized, am I am right?

I will indeed rely on gravity for my application; but the tube will be attached to an "extruder" module in constant linear motion. Depending on the angle of such tube, a bit of sand gets stuck on it; thus my need and idea to use a pump to help it move down at all times. If there is no way of making it work with an 8mm tube, I might be able to adapt the design to have a tube of up to 15mm - but for reasons too long for me to explain atm, that would be far from optimal.

Thanks again.

lgguts:
Do you have any indication to a small-scale air compressor that I could use for such purpose?

Most anything would work. It just needs to support the required flow rate so that it can maintain enough pressure to keep the sand moving. So it depends on your application.

lgguts:
Also: your solution implies that both containers are fully enclosed in order to be pressurized, am I am right?

The tank that the sand is being pumped out of (let's call it the "source tank") must be sealed other than the exit hose so that it can be pressurized. There is a large opening at the top that the sand flows through from the hopper. That opening has a ball valve that I close before pressurizing the tank. I've found that ball valves do work effectively in this gritty environment, though I'm sure it's hard on them. A needle valve or gate valve likely would not work since the grit would prevent it from closing completely. The tank that the grit is pumped to (let's call it the "destination tank") is not pressurized when the sand is being pumped into it. If they were both at the same pressure then the sand would not flow. I have a separate opening in that tank with a valve I open so that air can escape as it is replaced by the sand entering the tank so it remains at atmospheric pressure. Since the grit I'm pumping has been used over and over it has a lot of dust in it which I don't want to release into the air so the vent on the destination tank is piped into my sandblasting cabinet which has a dust collection system.

Once I have pumped the source tank empty I turn off the air supply to it, wait for it to depressurize, then open the fill valve so that it can start to collect more grit from the hopper as I use the sandblaster. I do pressurize the destination tank and in effect while I'm using the sandblaster I'm pumping the grit from the destination tank into the cabinet but this time the grit is mixed with a lot of air which makes it much more abrasive than the solid stream of grit that moves between the source tank and the destination tank while I'm refilling the destination tank.

lgguts:
Depending on the angle of such tube, a bit of sand gets stuck on it; thus my need and idea to use a pump to help it move down at all times.

You might consider using vibration to help the sand move down the tube. The basic idea is there is an offset weight attached to the shaft of a motor but you could likely buy the pre-made vibrator component rather than making it from scratch. The most common thing of this sort you would see in the Arduino world is a pager motor (the thing in the cell phone that makes it vibrate when you have the ringer turned off) but that's likely a bit on the small side for your application. I actually had something like this in my system at one point in time. I found one of these "Magic Fingers" units that bolts onto a bed and vibrates the whole thing. You used to find them with a coin slot in cheap hotels back in the days. I'm not sure if that's still a thing. That's just an example of thinking outside the box for sourcing something like this from some cheap consumer appliance.

It's possible you could even use your linear motion system to keep the sand moving through the tube by making it work in a rapid back and forth shaking motion rather than long smooth movements.

pert:
Most anything would work. It just needs to support the required flow rate so that it can maintain enough pressure to keep the sand moving. So it depends on your application.
The tank that the sand is being pumped out of (let's call it the "source tank") must be sealed other than the exit hose so that it can be pressurized. There is a large opening at the top that the sand flows through from the hopper. That opening has a ball valve that I close before pressurizing the tank. I've found that ball valves do work effectively in this gritty environment, though I'm sure it's hard on them. A needle valve or gate valve likely would not work since the grit would prevent it from closing completely. The tank that the grit is pumped to (let's call it the "destination tank") is not pressurized when the sand is being pumped into it. If they were both at the same pressure then the sand would not flow. I have a separate opening in that tank with a valve I open so that air can escape as it is replaced by the sand entering the tank so it remains at atmospheric pressure. Since the grit I'm pumping has been used over and over it has a lot of dust in it which I don't want to release into the air so the vent on the destination tank is piped into my sandblasting cabinet which has a dust collection system.

Once I have pumped the source tank empty I turn off the air supply to it, wait for it to depressurize, then open the fill valve so that it can start to collect more grit from the hopper as I use the sandblaster. I do pressurize the destination tank and in effect while I'm using the sandblaster I'm pumping the grit from the destination tank into the cabinet but this time the grit is mixed with a lot of air which makes it much more abrasive than the solid stream of grit that moves between the source tank and the destination tank while I'm refilling the destination tank.

This sounds amazing. I will certainly try with a tiny scale pump to see wether the results are satisfying for my needs - even though having a completely sealed tank in my case would require too much alterations to the already built structure. Nevertheless, thank you hugely for such a thorough description and help.

pert:
You might consider using vibration to help the sand move down the tube. The basic idea is there is an offset weight attached to the shaft of a motor but you could likely buy the pre-made vibrator component rather than making it from scratch. The most common thing of this sort you would see in the Arduino world is a pager motor (the thing in the cell phone that makes it vibrate when you have the ringer turned off) but that's likely a bit on the small side for your application. I actually had something like this in my system at one point in time. I found one of these "Magic Fingers" units that bolts onto a bed and vibrates the whole thing. You used to find them with a coin slot in cheap hotels back in the days. I'm not sure if that's still a thing. That's just an example of thinking outside the box for sourcing something like this from some cheap consumer appliance.

This is indeed a great idea! And it might suffice for my case. I will start with a Pager Motor and scale up to the air pressuring system if shaking it does not work. "Magic Fingers" is something new to me though ; ). But I get the principle.

Once again, amazing help and answers. Thank you hugely!

How about an Archimedes screw, could that be better for your usage case? It might grind a bit, but is popped into my head.Or maybe a small conveyor belt or vertical conveyor with buckets?