ELECTRICITY FROM WATER MILL WATCH VIDEO
8:46 PM
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The grinding stones are always inset slightly below the floor of the ghatta house in a square depression. Typically, the top stone is a little above the surface, but the bottom is well below. This square depression, well defined by four wooden boards, keeps the flour from spilling out onto the floor. The ghatta owner (ghattera) scoops the flour out of this sunken “box” when the grinding is completed. Water is typically diverted through a long (20-200 m) channel. Nearby the chute there is an alternative path for the water to flow when the ghatta is not operating. On the top of the chute is a gate that regulates water flow, prevents surface debris from entering, and serves as overflow protection. The chute is generally made of a hallow tree trunk, is placed at an angle of 40 to 50 degrees, and has a 3 to 7 meter head (vertical drop). The water flows down this chute and hits the angled 18×25 cm wooden planks that are the blades of the turbine. The main “shaft” of the turbine is a large piece of wood. The wooden plank-blades taper down to 6×6 cm pegs. These pegs are pounded into slots carved into the shaft. The slots are slightly angled relative to the vertical axis of the shaft, and thus the plank-blades are angled as well. A long metal rod (something like a very large nail) is hammered into the top of the wood shaft. This extends the shaft from below the ghatta house, up through the floor, through a hole in the bottom grinding stone, and connects finally to the top grinding stone. Where it passes through the bottom grinding stone, small slivers of bamboo or other light wood surround it. These slivers act as a collar for the extended turbine shaft to rotate in. They are replaced by the ghattera as they wear down, and are sometimes oiled as well to keep the ghatta running smoothly
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