Pumping Sand

Hi passingtongreen,

I think you are right on here, so GA.

Mike

There is sand and there is sand. How far do want to take it? And do you have height differences? What grid sizes, impurities, and do you do it indoors? Is it sharp or smooth? What is the specific gravity? What is the character when wet? Pumping with air in pipes will only work when really dry and for small grain size. Did you consider an Auger, Pipe wit Archimedes screw inside, transport belt with or without lobs? Then there is sand transport in water, works well but if you need it dry. that will be extra problems. Is this a long run project? The air system is about the most dusty, can generate toxines, and certain sands also create a explosive environment. And it is noisy and needs a lot of energy to waste.

Sorry, I ticked off too early. Also this: when your pressure falls out the sand in the pipes can become a nightmare to unclog them especially when moist binds it. If the pipe is chosen, rubber coating will last the longest. Maybe you would consider rubber thick wall suction hose? As far as wear: only for when the system is long term, you can consider air accellerator at the curves. It maintains the velocity and when installed on the outside also keeps the sand from grinding down the walls. It is a pipe through the wall and under small angle. When you use a turbine as suction device, you can send part of the output back into thes pipes to create a ventury suction extra. Less energy consumption.This is part of my previous post

Two big factors are how far and how fast you want to offload.

There is an entire industry devoted to sand and other bulk powder handling. Click here for a start

http://www.powderandbulk.com/search.php?q=sand

Why use piping and and pneumatics? If the customer is dead set on this, or it is too late in the game to change the design, then you are stuck with that solution. But if it isn't, then have you considered a drag chain conveyor system?

It sounds like your talking about an off-loading situation. You can move more bulk faster with a conveyor system than with air.

Just a thought.

I'd agree with this actually.

This company is well known for solid handling www.macawber.com.

Make sure you deal with equipment suppliers that understand this technology well or you will have maintainability problems. Not only can the piping wear but the diverter or pinch valves must be right for the job as well as other things.

For high density abrasive materials look into what is called a dense phase system. These operate at higher pressures but tend to move most of the material in slugs rather that the particles being suspended in high velocity air. This movement of slugs causes lower particle velocity and therefor less wear. Also the slugs enable movement of materials that are large and dense enough that they do not want to stay suspended in just high velocity air.

The lined pipe is quite expensive if you need much of it. Make sure the company that supplies the solids transport equipment also supplies the piping or at least makes a recommendation. You do not want finger pointing later. The transport velocity impacts the pipe wear very much so the piping needs to be part of the system. I have one solids pumping system that handles abrasives but due to low velocity (dense phase system) uses standard schedule 40 pipe on all straight runs. The elbows are standard sweep elbows with ceramic/epoxy filled boxes added to them on the outside. Experienced solids transport equipment suppliers are familiar with this method.

I am in agreement with Dave on this. I looked into pneumatic sand transport systems for dry sand transport in a foundry. You go to three reputable suppliers and let them tell you what you need. Practically everyone quoted me on the basis of schedule 40 steel pipe. It is at the elbows that special attention is required. Sticking with vertical and horizontal runs was typical. I believe they recommended a slight slope on the horizontal runs.

There are different approaches as far as pulsing-laminar flow-dense phase, etc. and they all have their benefits vs. down sides. Let them size it and quote it but you really will find some big savings in sticking with the steel pipe vs. lined. They may even have a LDPE piping system available if this is only a short time project vs a permanent one. I found that LDPE wore better than steel in many places in a foundry sand application.

Well, thanks for all these responses. The sand is a dry natural product, not crushed, I'm told this makes it less abrasive than crushed and sorted products. I'm asking about options for conveying so the supplier can send dump trucks instead of trucks with eductors and blower. The client is interested in basalt-lined pipe, the length is about 70 feet, and there are only a couple bends in it, one 90 and a couple 45's. I'm trying to get more detailed info about blower capacity so I can determine velocities in the piping and check sizing. The supplier says that he uses 15 psig air to convey 12 tons/hour through 4" pipe. Dense phase transport is interesting, I'll also talk to the supplier about that. I did away with the incline, but I'm not sure I understand what the angle of repose has to do with it. Anyone care to clarify that idea?

Thanks again, I'll post anything interesting that comes up.