We explain what a mill is, its origin, history and how it works. In addition, the characteristics of each type of mill.
What is a mill?
A mill is a type of machinery used to take advantage of the Kinetic energy. That Energy It can come from the wind (aeolian or wind mill), from the Water (hydraulic or water mill), or animal traction (blood mill), to carry out mechanical tasks such as grinding materials or generating electricity.
In its agricultural version, intended to grind edible grains, it is one of the oldest inventions of humanity, which has different names depending on the region and the specific use that is given to it. Thus, for example, they speak of an oil mill for the mill used in olive plantations, and a mill or mill for the mill used to crush sugar cane.
Traditional mills are a traditional part of the scenery in different geographies from Europe, and have been portrayed in artistic works as symbols of local culture, as is the case of the windmills in the Don Quixote by Cervantes, or in the Van Gogh series Le Moulin de la Galette .
Origin and invention of the mill
The first mills arose in remote antiquity, in the framework of the Neolithic Revolution in which the farming was installed as the main activity of the humanity. They were destined to crush cereals and grasses to produce flours, but also some types of tubers, seeds and collected fruits.
Initially this work was carried out manually, with piles and mortars of different materials, which were used to crush the materials between two flat stones.
However, as it was an arduous and repetitive task, it took methods more expeditious and continuous, which probably arose with the use of pack animals, by means of rudimentary blood mills. In the absence of animals, it is probable that slaves were also used for this work, as evidenced by certain biblical and classical accounts.
The invention of the mill, in any case, is uncertain. The first historical description of one of these artifacts comes from the Pneumatics by the Greek engineer and inventor Philo of Byzantium (280-220 BC), and consisted of a water mill probably invented sometime in the 3rd century BC. C.
These hydraulic mills were also known to the Romans and used from the 1st century BC. C., judging by the descriptions made by Vitruvius (81-15 BC), the famous Roman architect and military man.
How does a mill work?
If we have ever used a pepper or coffee grinder, we will be familiar with the system that makes up grinders alike. It is, in principle, an instrument to convert a type of energy (kinetic, from wind or water, or biochemical, from living beings that push) into another (mechanical, gear, or electrical, if there are turbines) usable for specific tasks.
In principle, a mill has a set of blades fixed to a rotating shaft. When the specially designed blades are pushed by wind or water, they rotate the shaft, which in turn transmits, via a colossal gear, its movement to another horizontal axis, at the end of which there is a moving stone, circular in shape, called a grinding wheel.
The latter, by turning on its axis, crushes everything that is poured underneath: grains, cereals, olives, sugar cane, etc., thus allowing to obtain flours, juices or oils, as the case may be.
This principle operates regardless of whether the mill depends on the wind, the water of a river or the tide of the coast. It is applied in a similar way in the case of windmills destined to produce electricity, with the exception that, instead of the grinding wheel, these devices have an electric turbine and an electric generator, in order to transform the movement into electricity.
Mill types
Mills can be classified according to the type of energy they use:
- Blood mills. When is the force of an animal (or of persons) which mobilizes the rotary axis of the mill.
- Windmills. When it is the force of the wind that blows the one that mobilizes the blades of the ingenuity.
- Watermills. When it is the force of a river that mobilizes the blades.
- Mills combustion. When the force that moves the shaft comes from the combustion of chemical substances (fuels).
- Electric mills. When they consume electricity to mobilize the rotary axis.
They can also be classified according to the task performed, in:
- Grinding mills. When they have a grinding wheel to grind and transform food.
- Generating mills. When they have the task of activating electricity generation turbines.