Ring-Disk Spiral-Pin Churn: Cream Forced Out Between Corrugated Rings, Then Drawn to the Middle by Spiral Pins

"The milk or cream thus entering while the disk G is in rapid motion, it will be seen that (by the centrifugal force developed) the fluid will be forced outward, but, meeting the obstruction of the rings, will be checked—accumulate to some extent until forced to climb over and around them, successively advancing thus and being checked and being thereby subjected to the action of the corrugated surfaces upon each side of the rings"

From 20 mm hardwood make a box 300 x 300 mm and 450 mm deep inside with a lid bored 21 mm in its middle. Bore one side 13 mm, 10 mm above the floor in its middle. Bend a 12 mm stainless tube to run from outside, through that hole along the floor and up into F's inlet, seal it through the side, and fit a stainless funnel on its outer end as the hopper. Fill the box with water overnight so it swells tight, then empty it.

Stand F on its feet in the middle of the floor over the spout. Plane a hardwood shaft to a hexagon 40 mm across the flats and 393 mm long, with a 19 mm square socket 30 mm deep in its top, and pin its foot in G's hub. Bore twelve 16 mm holes through it from 35 to 332 mm above its foot, 27 mm apart, and glue in hardwood pins reaching 135 mm from the middle: the lower six turning 60 degrees each from the foot upward, the upper six the same from the top downward, so the two spirals meet at the middle. Set G's journal in F's bearing.

Pass a 20 mm stainless stud through the lid, square at its foot to drop into the shaft's socket, with the pinion pinned on top. Fix a second stud in the lid 96 mm away carrying the gear wheel, meshing, with a crank and handle on it. Lift the lid to free the shaft and disks for cleaning.

Turn the crank and pour heavy cream at about 15 °C, checked with the thermometer, into the hopper, about 15 litres in all, keeping the disk turning fast. Keep turning, timing it. When the butter comes the pins gather it in the middle: lift the lid, take out the shaft and the butter, drain the buttermilk, wash the butter in cold water until it runs clear, salt and weigh it.

**Daniel C. Brown** of New York, US 26,880, 24 January 1860, "Churn". He claimed the disks F and G with the rings on their inner sides. His disks were wood or metal; ours are printed. His hopper is a jointed bucket; ours is a funnel on a tube. The patent gives no sizes; every size here is ours.