Roller mill
Encyclopedia
Roller mills use cylindrical rollers to grind all sorts of materials rather than crushing them or grinding them between stones such as in a traditional grains mill
. Roller mills are usually used for industrial grain milling (Agriculture
) and for grinding gravel into smaller rocks or pulverizing them. The roller mill is a relatively new kind of large scale power mill which is designed specially to solve the problems of low capacity and high consumption of industry mills. It is a necessary equipment for the high production of mineral powder in the non-metal mine industry and large scale powder making in many other industries. The product size is adjustable in the range of 0-2.8mm.
The endosperm portion of the kernel makes up about 80% of the volume and is desirable because the products produced by this white flour are often considered to have milder flavor, smoother texture, and, in the case of bread, greater volume. The balance of the kernel is composed of the bran and the germ which tend to be coarser. With the invention of the roller milling system in the late 19th century, the bran and the germ were able to be removed, dramatically improving the appeal of baked products to the public.
The moistened grain is first passed through the series of break rollers, then sieved to separate out the fine particles that make up white flour . The balance are intermediate particles of endosperm (otherwise known as product "middling" or "farina") and coarse particles of bran and germ. The middling then makes multiple passes through the reduction rolls, and is again sieved after each pass to maximize extraction of white flour from the endosperm, while removing coarser bran and germ particles.
To produce "whole wheat" flour, 100% of the bran and germ must be reintroduced to the white flour that the Roller Milling system was originally designed to separate it from. Therefore, these elements are first ground on another mill (usually a pin mill). These finer bran and germ fractions are then reintroduced to the endosperm ("white flour") to produce whole wheat flour
made of 100% of the kernel of wheat.
or porcelain
rollers.
at the inlet and outlet of the grinder to prevent dust and radiating the heat in the machine.
Gristmill
The terms gristmill or grist mill can refer either to a building in which grain is ground into flour, or to the grinding mechanism itself.- Early history :...
. Roller mills are usually used for industrial grain milling (Agriculture
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
) and for grinding gravel into smaller rocks or pulverizing them. The roller mill is a relatively new kind of large scale power mill which is designed specially to solve the problems of low capacity and high consumption of industry mills. It is a necessary equipment for the high production of mineral powder in the non-metal mine industry and large scale powder making in many other industries. The product size is adjustable in the range of 0-2.8mm.
Producing Wheat Flour
To produce refined (‘white’) wheat flour, grain is usually tempered, i.e. moisture added to the grain, before milling, to optimize milling efficiency. This softens the starchy "endosperm" portion of the wheat kernel, which will be separated out in the milling process to produce what is known to consumers as "white flour”. The addition of moisture also toughens the bran and ultimately reduces the energy input required to shatter the kernel, while at the same time avoiding the shattering of bran and germ particles to be separated out in this milling process by "sieving" or sifting.The endosperm portion of the kernel makes up about 80% of the volume and is desirable because the products produced by this white flour are often considered to have milder flavor, smoother texture, and, in the case of bread, greater volume. The balance of the kernel is composed of the bran and the germ which tend to be coarser. With the invention of the roller milling system in the late 19th century, the bran and the germ were able to be removed, dramatically improving the appeal of baked products to the public.
The moistened grain is first passed through the series of break rollers, then sieved to separate out the fine particles that make up white flour . The balance are intermediate particles of endosperm (otherwise known as product "middling" or "farina") and coarse particles of bran and germ. The middling then makes multiple passes through the reduction rolls, and is again sieved after each pass to maximize extraction of white flour from the endosperm, while removing coarser bran and germ particles.
To produce "whole wheat" flour, 100% of the bran and germ must be reintroduced to the white flour that the Roller Milling system was originally designed to separate it from. Therefore, these elements are first ground on another mill (usually a pin mill). These finer bran and germ fractions are then reintroduced to the endosperm ("white flour") to produce whole wheat flour
Whole wheat flour
Whole wheat flour is a powdery substance derived by grinding or mashing the wheat's whole grain. It is used in baking but typically added to other "white" flours to provide nutrients , texture, and body to the finished product....
made of 100% of the kernel of wheat.
Gristmill conversion
In the 19th century roller mills were adapted to grist mills before replacing them. The mill used either steelSteel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
or porcelain
Porcelain
Porcelain is a ceramic material made by heating raw materials, generally including clay in the form of kaolin, in a kiln to temperatures between and...
rollers.
Other applications
- Specialized for the high production of superfine pyrophyllite powder making in glass fiberFiberglassGlass fiber is a material consisting of numerous extremely fine fibers of glass.Glassmakers throughout history have experimented with glass fibers, but mass manufacture of glass fiber was only made possible with the invention of finer machine tooling...
industry - Specialized for the high production of gangue powder making in coal industry
- Specialized for the high production of various of chemical raw material powder making in the chemical industryChemical industryThe chemical industry comprises the companies that produce industrial chemicals. Central to the modern world economy, it converts raw materials into more than 70,000 different products.-Products:...
.
Similar Devices
Other mill systems include:- Stone Mill
- Unifine MillUnifine millA Unifine mill is a single one-pass impact milling system which produces ultrafine-milled whole-grain wheat flour that requires no grain pre-treatment and no screening of the flour. Like the grist or stone mills that had dominated the flour industry for centuries, the bran, germ, and endosperm...
or Impact Mill
Working principle
While working, motor drives the hanger of the grinding roller to rotate through V pulley and centre bearing. The roller, which is hung by bearing and pendulum shaft, will roll along the inner circle of the roll ring while the hanger is rotating. A dust removal blower will generate negative pressureNegative pressure
Negative pressure may refer to:*negative pressure as opposed to positive pressure*stretched liquid*vacuum*negative gauge pressure, a way of expressing pressure measurements below atmospheric pressure*suction*transpirational pull...
at the inlet and outlet of the grinder to prevent dust and radiating the heat in the machine.