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Description of the Diagram
As the selected wheat comes into the mill it is carefully weighed and put into storage bins of very large capacity, equipped with thermometers which indicate the temperature of the stored wheat in the various parts of the containers at all times. As the wheat is received into the mill from these storage bins it passes into a screening machine which separates the small seed from the wheat by allowing the cereal to flow over a large plate having tiny perforations, while the plate is in a vibrating motion. The small seed such as hemp and mustard fall through the tiny perforations and pass off into a screening container while the wheat passes on to another screening machine having a similar metal plate containing larger perforations through which the wheat passes while the larger seeds are forwarded into a chute which leads them into another screenings container. From here the wheat passes into dry scouring machines which agitate the wheat allowing the dust to be removed by blowers and passes the scoured wheat off into a washing machine where the wheat is washed with water. As the wheat is being agitated with the water in this machine the dust and dirt in the crevices of the wheat are washed Received Wheat Screening Machines Screenings Wheat Scouring Machine Dust Scoured Wheat Washing Machine Waste Water Washed Wheat Drying Machine First Grinding Middlings Second Grinding Middlings Third Grinding Middlings Fourth Grinding Middlings Fifth Grinding Middlings Bran Blended Middlings ↓ ↓ Nal Grinder No2 Grinder No.3 Grinder No4 Grinder Bian Bran Bran Bran Pure Middlings Pure Middlings Reducer Reducer Reducer Reducer Flour Flour Flour Flour Middlings Middlings Middlings Middlings Flour Flour Flour Flour First Clear Second Clear Red Dog out. After the washing is complete the waste water passes off while the wheat passes out and is tempered with more water to soften the bran coating. It is surprising to find the amount of dirt which is washed from the wheat by the washing machine. From here the wheat passes into drying machines where the excessive amount of moisture is evaporated. Next the wheat comes to a series of grinding machines or mills. These mills contain two rollers travelling at different rates of speed. The rollers are corrugated, usually having from 10 to 14 corrugations to the lineal inch. As the wheat passes through these rollers it is crushed, thus removing the largest portion of the bran in a flaky form while the middlings pass through in a gritty state. After the middlings have passed through a series of these grinders they are blended when they are ready for grinding through a series of mills having smaller and more indentations per lineal inch of the rollers. By passing through this series of grinders more bran is removed and the middlings come out in a finer state. After the middlings leave these grinders they are known as purified middlings and are ready to go through a series of grinders having smooth rollers known as reduction mills, until they have been reduced to flour. After each grinding the middlings are passed over bolting cloths where some of the flour is separated. The last bran particles which are removed from the middlings are again passed through a series of grinders where they are reduced to first clear, second clear and red dog flour. It is possible to produce flours of different quality by extracting different percentages of the wheat berry and reducing it to the flour stage. More clears are produced when a patent flour of low extraction is made. Physical Properties of Hard Wheat Flour. The baker prefers a flour having a very light, creamy color. A good patent flour will be very light in color, while the low grade flours will be tinted gray and sometimes yellowish, depending upon the color of the wheat from which they were milled. The coloring matter in flour is soluble in the fat present and can be extracted with petroleum ether or gasoline.