First Week Progress

Due to the difficulty of transporting the parts I’m uploading a photo of the sand delivery system in lieu of an in-class presentation.

On the 2×4 is a water pump capable of producing 130PSI. It pumps water from the orange bucket into the right pressure tank, through a port on the bottom. This compresses the air inside. A port at the top allows the tank pressure to be measured through a linear analog pressure transducer. A solenoid valve seen at the lower left of the plywood board allows high pressure water to enter the sand tank, which is the thin white pipe at left. As water comes in, it displaces sand and water, ejecting it through a 1/8″ hose. The first iteration used the larger 3″ PVC tank at the far left, but a void was forming as new sand would not replace the sand ejected. The smaller pipe concentrates the sand over the outlet port. Additionally, the water inlet was added at the bottom to help agitate the sand.

The main difficulty I am having at the moment is getting precise control over the sand flow. After closing the solenoid valve, it continues to dribble for a second or two which makes precision use difficult.

I also have a 8″ long, 3/8″ diameter lead screw with a cog and matching stepper motor which I am considering using as a feed screw to make an extruder. Dealing with leakage is the most difficult part with this.