Volute Shaped Blower Primitive Technology

I made a helical shaped blower where the housing for the fan is helical shaped, i.e. a wide spiral, to test the effectiveness of the one-way rotating propeller. The rear blower design is teardrop shaped, so the direction of fan rotation is not critical. Also with the previous design the propeller rotates in one direction and then in the other, as it is driven by a simple string mechanism.

In the new design, a weight was employed in the form of a heavy log attached to the rotor. The top of the rotor is held in place and a weight is rotated to create rotation. This method produces lower RPM than the original but allows the fan to rotate continuously in only one direction. To compensate for the lower RPM, the fan size was doubled (25 cm to 50 cm) to increase blade tip speed and air speed.

Now with a fan that only rotates in one direction, a housing can be used to take advantage of this fact. The volute is an extended spiral and the housing for the fans is shaped like a volute which helps guide air from the center to the outlet more efficiently than the tear drop shape. It was built using clay on the ground rather than portable clay as it began to become too large to transport.

The fan was tested in iron smelting. Disappointingly, due to the lower RPM and therefore air pressure compared to the original blower it produced only a small amount of iron in the form of much smaller prills than usual. After some rough calculations from research, this design could become competitive with the original blower if the fan diameter was increased from the original 25 cm diameter fan to 1 meter diameter.