Whirl-Frame Air Dasher Churn: Free Wheels Spun by the Milk Inside a Revolving Frame

Routzahn put free-turning wheels inside his dasher so the milk itself would spin them. Nathaniel Routzahn of Middletown, Maryland, received US 7,199, dated 19 March 1850, for a churn-dasher of two L-shaped tubes of triangular section, running from near the cover down and in to the spindle, their horizontal arms perforated "through which air enters the milk during the revolution of the dasher." Between each upright arm and the axis, standards carry "whirls B, or wheels having inclined spokes," free to turn in planes through the axis. A bevel wheel and pinion turn the dasher fast, and "the friction thus produced by the whirls greatly facilitates the separation of the butter." This rung estimates how the whirls spin, then prints the hollow frame and two whirls, fits them in a bucket, and makes butter.