Science Buddies: "Ask an Expert"

I have to build a working model to depict how pipeline conveyance of river silt can be used in wetland restoration. I need some advice on the type of pump to use to move silt from on container to another. Would a handmade pump work work? Or a simple fountain pump?


I appreciate your help.

Clay
6th grader

Hi,

I really am not familiar enough with pumps to know. I think our physical science experts may be better able to advise you--hence the topic move.

But, my guess is that if you're pumping silt, unless it's really watery silt, you're going to need a special kind of pump. The particles in the water will increase the viscosity of the water and you will need more force to move the silt along.

Here's hoping the physical scientists can help more than I can .

I don't know anything about pumping silt; however, you might do a little research on
1) concrete pump design, and
2) hydraulic dredging equipment design

Concrete is a mixture of sand, gravel, and portland cement (which is at least 2/3 calcium silicates). The concrete industry has come up with several different pump designs but most involve a hopper where the material must be lifted into and then a hydrolic piston action is used to push the material down a semi-flexible pipe. Concrete mixes designed for pumping usually have some chemical modifiers to lubricate the flow of the material through the pump and piping.

The EPA has some information on hydralic dredges:
http://www.epa.gov/greatlakes/arcs/EPA- ... l#RTFToC79

BEWARE: You may have some difficulties in doing this in a small scale model.
1) The ability to move a slurry through a small diameter pipe is going to take a LOT of pressure. Capillary forces (resistance to flow) go up faster than the cross sectional area decreases.
2) Silt (contains silica) is abrasive which means it will wear out anything it moves against and has a lot of friction

If you are just trying to demonstrate how something works and not perform any scientific experiments, you might consider demonstrating with a different material. Something like making a slurry out of chocholate or butterscotch pudding (the kind you would cook to have it set up - but don't cook it - you don't want it to set up, and definitely NOT INSTANT pudding). If you want the material to be translucent, a jello slurry might work. These kinds of materials could be pumped by miniture pumps used to clean out aquariums if you keep the mixture watery enough (low viscosity).