Grist Mill Diagram

Thorp Grist Mill diagram

3. Sifting, Lateral Transport

Haggenmacher Plan Sifter

The top floor contained a Haggenmacher Plan Sifter, which was installed in 1900 by raising the roof of the mill 1/2 story to accommodate the sifter and its frame. The sifter was suspended from the raised ceiling with wooden dowels and powered by a bottom wheel with 40 sieve plates of varying sizes that moved and shook the grain down into different sizes. Invented in 1888 by Hungarian miller Carl Haggenmacher, the sifter was a productive innovation that avoided the excessive gyration found in earlier designs and produced more grain from a single bushel than previous sifters.

2. Cleaning, Temporary Storage

Whitemore Air Purifier

The second floor contained the mill’s cleaning machine, which used forced air to vent chaff and other debris from the grain. This purification process created a higher quality product that sold for better prices. The Air Purifier shown here was manufactured by the Whitemore Purifier Company, Three Rivers, Michigan.

1. Final Processing

Jewell Sack Packer

The main task in final processing was to sack the grain using a weight-triggered sacking machine that automatically filled each bag until it reached a specific weight. An operator would then tie off the full bag and replace it with a new empty one to start the process all over again.

The first floor also contained the head miller’s office, which served as the business nerve center of the entire milling operation. To reduce the risk of fire in an operation filled with flammable milling dust, the miller’s office was the only heated room in the entire building and was closed off from the rest of the mill’s operational areas.

B. Power System, Vertical Transport

Turbine flywheel attached to main belt

The basement floor contained the mill’s power wheels, which were turned by mechanical energy transferred from the mill’s water turbine using a system of belts. This was the mill’s sole form of energy that powered all milling operations, including the mill’s vertical conveyor system, which used a series of cups attached to vertically aligned belts to transport grain between floors during processing.