Oliver Evans’ Improved Grist Mill

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Winter in the Country – The Old Grist Mill by George Henry Durrie (1820-1863).
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An engraving of Oliver Evans by H.G. Jackman.
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An engraving of an Oliver Evans-designed flour mill from his 1795 book, The Young Mill-Wright & Miller’s Guide.

Flour was an important commodity to early American settlers. Many ground their flour in a pestle made of a hollowed-out tree stump. The mortar was a piece of log suspended over the stump by a rope from an overhanging branch or sapling. The spring action of the branch gave some lift to the mortar as the operator lifted and then dropped it to pound the grain into flour. Sometimes a crude stone hand grinder called a quern was used, but either process was slow and laborious. In an early account of frontier life in Ohio, the author writes: “I well remember that in 1791 so scarce and dear was flour that the little that could be afforded in families was laid by to be used in sickness, or for the entertainment of friends.”

As the number of settlers in an area grew, some enterprising individual would build a water-powered mill along a stream. The neighboring farmers then made regular trips to the mill, carrying “grists” of grain to be made into flour. As fee for his services, the miller typically took one-tenth of the grist, an amount set by law in most states. Since farmers didn’t want to travel far for flour, mills sprang up everywhere, often only three or four miles apart. The early mills were slow, inefficient and labor intensive, and furnished many opportunities for contamination of the flour by dirt, insects and vermin.

Evans the innovator

Oliver Evans changed all that. Born in Newport, Del., on Sept. 13, 1755, at 16 Evans was apprenticed to a wheelwright who taught him to build wagons. Being curious and ambitious, the young man studied math, mechanics and science in his spare time and developed into an excellent “mechanician,” as they were called in those days.

Evans joined his two brothers in running a grist mill. Being inventive, he set out to improve the way flour was made. He designed bucket elevators to raise the grain and flour vertically and chutes to carry them back down, along with screw conveyors to move them horizontally through the mill. He also developed a rolling screen to clean the incoming grain before it was ground.

When freshly ground flour first came from the mill stones, it was hot and damp. To prevent caking, it had to be stirred while it cooled and dried. Standard practice was to spread the flour on the floor, where a miller’s boy stirred it with a hand rake until it was dry and cool. The procedure took a long time and was inherently unclean. Evans developed a machine, appropriately named a “hopper boy,” that performed the operation with a large mechanical rake inside an enclosed bin.

In the 1780s, Evans built a completely automatic grist mill in New Castle County, Del. Powered by a water wheel, the mill was the first continuous flow, production line mill in the world. An English book of the day described the mill: “Mr. Oliver Evans, an ingenious American, has invented … a flour mill upon a curious construction which, without the assistance of manual labor, first conveys the grain … to the upper floor, where it is cleaned. Thence it descends to the hopper, and after being ground in the usual way, the flour is conveyed to the upper floor, where, by a simple and ingenious contrivance, it is spread, cooled, and gradually made to pass to the boulting hopper.” The product wasn’t touched by human hands from the time the grain was dumped into the receiving hopper until the finished flour flowed into a bin ready for packing into barrels or bags.

Newfangled ideas finally take hold

Like many inventions, Evans’ mill machinery was slow to be accepted. Millers were like farmers and looked with suspicion upon any new method or machine different from that used by their fathers and grandfathers. Eventually, mills began to incorporate some or all of Evans’ improvements. Since there was no patent protection during the 1780s, Evans usually received no money for use of his ideas by others. Finally, the U.S. Patent Office was established in 1790. The third patent issued by that body was to Oliver Evans for “his method of manufacturing flour and meal.”

Sometime in about 1800, Thomas Jefferson had a grist mill built, leaving all details of construction to his millwright who borrowed heavily from Evans’ methods. In 1808, President Jefferson found out about the patent and wrote to Evans, “I am informed and indebted to you for the machinery erected and interest on it, $89.60 [$1,545 today], which sum I therefore now remit you in a draft on the Bank of the United States.” Evans replied, acknowledging the payment, ” … for license to use my improvements at your mill at (Albemarle) County for which I return you sincere thanks … I can say with truth that had all those who had used my improvements paid as generously as the President of the U.S., I might have been enabled to render my country much greater service.”

But mills weren’t all. In 1803, Evans reportedly was the first person to successfully burn coal in a grate. Up to that time homes were heated by wood fires, with coal used primarily in blacksmith’s forges and in making ammunition. In 1805, he designed probably the first refrigeration machine, although it wasn’t until 1844 that a doctor named John Gorrie improved on Evans’ design to build a machine that made ice to cool yellow fever patients.

In Buffalo in 1842, Joseph Dart built the nation’s first grain elevator to load and unload grain from canal and lake boats. Prior to that, all grain was hand-loaded and unloaded by laborers, or “Irish backs,” as one grain merchant put it. Dart’s elevator could move more than 1,000 bushels per hour. Grain elevators soon became common in every grain shipping port. Dart later said, “It was the first successful application of the valuable inventions of Oliver Evans to the commercial purpose for which it is now extensively employed.”

Branching out to steam

Scotsman James Watt is famous for improving Newcomen’s steam vacuum engine that relied on atmospheric pressure to move the cylinder. Watt developed a double-acting cylinder that alternately admitted steam on each side of a piston to provide a powered stroke in each direction. While Newcomen’s engines were used primarily for pumping water, Watt’s improved low-pressure engines were practical for running other machines, but they were large and heavy, limiting their usefulness in vehicles.

As a young man, Oliver Evans had studied Newcomen’s engine and became fascinated by this new source of power. During the 1780s, Evans designed and built a high-pressure, non-condensing steam engine that was compact, lightweight and of simple construction. While Watt is credited with inventing the low-pressure steam engine, Oliver Evans built the first high-pressure engine. FC

Sam Moore grew up on a farm in western Pennsylvania. He now lives in Salem, Ohio, and collects antique tractors, implements and related items. Contact Sam by e-mail at letstalkrustyiron@att.net.

For more on grist mills, read a first hand account of A Trip to the Grist Millfrom the May 2011 issue.

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