At one time, the windmill was an important structure that allowed a large number of operations. With its help, it was possible to easily grind grain into flour or feed for livestock. Today, no one uses mills that would operate from the flow of wind or water, but they are successfully used in landscape design. What is the working principle of the mill and is it possible to assemble it yourself? This will be discussed in the article.
Principle of operation
The operating principle of a windmill can be described quite simply. Air currents that constantly move are used as the driving force. The wind affects three main nodes:
- blades;
- transmission mechanism;
- mechanism that does the work.
In mills that were used before, the blades could be several meters long each. This was done to increase the wind capture area. The dimensions were selected depending on what function the mill performed. If more mill power was required, then the propeller was larger. The mills that ground flour were equipped with the largest blades. This is due to the heavy millstones that had to be rotated. The shape of windmill blades has improved over time, and they were created in accordance with the laws of aerodynamics, which made it possible to increase their efficiency.
The next module of the windmill, which follows the blades, is the gearbox or transmission mechanism. Sometimes only the shaft on which the blades were mounted served as such a module. At the other end of the shaft there was a tool that did the work. But such a windmill mechanism is not particularly safe and reliable. It is simply impossible to stop the mill if necessary. In addition, the shaft could easily break if something jammed it. A gearbox is a more efficient and elegant solution. It is suitable for converting the rotation of the blades into useful work of various nature. In addition, by disconnecting the gearbox components, the interaction can be easily stopped.
The equipment that could be used and is used with the mill is very diverse. In addition to millstones, these can be various grinders based on blades, thanks to which short time You can prepare feed for livestock. Mills could have carpentry equipment that was powered by wind.
Where can the mill be used?
Mills are experiencing a rebirth, but this is not due to a return to production methods that were used before. More and more people are wondering about the principle of operation of such a design. Those who saw with one eye a small windmill that was installed in someone’s garden wanted to have a windmill on their property. The mill can be exactly the highlight that was missing for the garden area with trees. The mill adds personality to any area. It is difficult to find two identical mills that were made by hand. Each master brings his own achievements.
The windmill can be modified and used as a generator electrical energy. This will allow you to illuminate the yard using LED bulbs and not pay for electricity. This will require certain knowledge of physics and ingenuity. In a similar way, you can use a mill if a small stream flows through the area.
Approach to landscape design should be moderate. You can plant a variety of flowers and other plants without much difficulty, but it will look tasteless. Each project should have its own highlight. You can rarely surprise anyone with an evenly trimmed lawn. A mill on the site will provide an opportunity to stand out. Near it you can set up a small corner for relaxation after a hard day; it can be a hiding place for little things dear to your heart. Other possibilities for using such a mill are described below.
Additional uses
A windmill can be not only a generator and a simple element that will decorate the site. She may have something else practical use. That is why it is worth thinking carefully about where exactly it can be installed. For example, if by garden plot If an automatic watering system is installed, then most likely there may be a hatch in which all water supply units are located. Such a hatch cannot be hidden under lawn grass, but if this is not done, then it will stand out and spoil the look. Just in this case, a mill will come to the rescue. It can be mounted directly on the hatch cover, thereby hiding it. At the same time, visitors will not have any suspicion that something is wrong.
Sewerage elements are not always hidden in hatches. In addition, there may be other elements on the lawn that need to be hidden. Due to the fact that the material selected for the mill is light, it cannot damage the elements. The housing is also made in the form of a cap, so it can be installed on top. If you build a mill of large dimensions, then children will be endlessly happy about it. They will be able to use the mill to play with friends. If the structure is to be used in this way, then it must be well strengthened so that it does not injure the children. In addition, you will need an entrance, which must be made from the back side.
A lot of tools are used to care for the garden and lawn. It is more convenient if it is located directly on the site and you do not have to return to the storage room near the house for it. A mill can help with this too. Inside the mill you can equip an excellent room for storing equipment. To keep it as compact as possible, you can build various garden organizers. The mill can be built from natural stone or fire bricks. In this case, you can think through everything so that it serves as a barbecue. You can also build a small table for this.
Note! A problem for many are moles, which constantly dig into the garden. This issue can be partially resolved using a mill. It is capable of transmitting vibrations from rotation. This is done due to the fact that the legs are dug into the ground at least 20 cm. Additionally, vibration motors can be mounted in the windmill structure, which will scare away animals.
DIY making
Making a mill should not be taken lightly. Although the design of a windmill may seem quite simple, everything must be calculated correctly. Only in this case can you get a truly worthwhile product that can decorate the site. The first step is to select the area where the wind turbine structure will be installed. If you place the product between trees, it will get lost there and will not be pleasing to the eye, in addition, the wind force between the trees is less, so the rotation of the blades may be practically absent, which will be bad if there is a generator inside.
Note! It is easier to deliver the required materials to open areas, and it is also easier to assemble the windmill blade structure.
After selecting a site for a windmill, it is cleaned and prepared. The first step is to clean up various elements, which may interfere. This applies to old branches, bushes or large weeds. If a tree previously grew on the site, you will need to uproot the stump. After harvesting, the grass is removed and removed small area soil in the place where the mill will be located. Next, the foundation is prepared on which the windmill will be mounted.
Drawing
There are no strict rules for assembling your own version of the mill. The main task will be to draw a good schematic drawing. It should show all the details of the mill. Depending on the selected area and the purposes assigned to the mill, the dimensions are selected. They must be indicated directly on the sketch. An example is visible in the photo above. The next step is the selection of material for the mill. Wood is suitable, but it must be treated with an antiseptic and also varnished so that it does not swell from moisture and is not eaten away by pests.
Note! An excellent solution for the design of a windmill would be pine. It is impregnated with resins, so it perfectly repels moisture. The cost of such wood is relatively low, so it is perfect for the intended purpose.
Foundation preparation
When everything is clear with the dimensions, you can move on to making a foundation for the windmill. This is an optional procedure, but it is required if the windmill is of significant size and is used as an office space. A small hole is dug to a depth of 50 cm. A layer of crushed stone is added in a layer of 15 cm, and medium-grained sand is laid in the same layer. It must be well compacted and leveled so that the windmill stands level. Next, the formwork is set to the height to which the foundation for the wind turbine will rise. In most cases it is not required.
A reinforcing mesh is placed inside the hole under the windmill foundation. It is made of reinforcement, which is intertwined with knitting wire. Concrete is poured from above. It must be compacted well so that there are no voids that could cause cracks in the windmill foundation. Installation of the windmill on the foundation can be done after a few weeks.
Assembly
First of all, you will need a frame for the mill. It can be made from wooden beam with dimensions 5x5 cm. It must not be attached to concrete base, but to a small grillage. It can be made from timber with a size of 10×10 cm. A square or rectangle is made from timber. Everything will depend on the chosen design. The elements are firmly connected to each other. It is necessary to check whether each goal corresponds to 90°. After this, a layer of roofing felt waterproofing is laid on the foundation under the mill. It is necessary to prevent moisture from the concrete from damaging the wood. Placed on roofing felt wooden structure the base of the windmill and screwed to the base with anchors.
The next step is to install a frame made of logs. Stands for the mill are attached to the four corners. Most often, the walls of the mill have a trapezoidal shape, so the bars are not attached at a right angle, but with a slight slope. To do this, they must first be trimmed. Fixation to the base is carried out metal corners. Once the four mill posts are in place, the top trim is made. Additionally, transverse struts are attached, which will increase the strength of the entire mill structure. This is exactly the moment when it is necessary to strengthen the places where the window and doors will be located.
The next step is to construct the roof of the mill. A small one looks great in windmills gable roof. Triangular trusses are constructed from the bars and mounted on top of the mill. After this, all the walls of the windmill, except the front one, are covered. Windmill casing can be done wooden clapboard or block house. Closer to the roof, on the front side of the windmill, a mechanism is fixed on which the blades will be installed. This could be a pipe into which several bearings are pressed. You can attach it to the horizontal crossbars of the windmill frame using clamps. A metal shaft from the blades is inserted into the bearings. It can be made from a piece of reinforcement.
One of the most complex elements of a wind turbine is the propeller. Above is an approximate design of windmill blades. The dimensions can be increased proportionally depending on the dimensions of a particular wind turbine design. After this, the propeller is installed on the previously prepared shaft. Now you can sew up the front wall of the windmill. Next, a window and doors are installed in the windmill, and the internal space is also organized. Corrugated sheeting or metal tiles are suitable as roofing for a wind turbine. A video about assembling a decorative windmill is below.
Note! It is important to provide a mechanism that will lock the windmill shaft. This will be needed during strong wind so that the windmill blades are not damaged.
Summary
As you can see, a windmill or windmill can be quite a useful addition to the garden. Thanks to its unique appearance, the windmill will definitely attract the attention of passers-by and guests. In addition, a windmill will greatly simplify the task of garden maintenance. Pumping equipment and main control units can be placed inside the mill, which will protect them from adverse weather conditions.
The history of the use of wind energy by man goes back to ancient times. The very first mention of this appeared around 1000 BC. The history of windmills in Western countries is believed to date back to the first documented appearance of a Danish or European windmill in 1180 in Normandy. Most likely, windmills came to Europe from Persia through the Mediterranean countries.
The most famous early type of this device is the Persian mill, which was a rudimentary device with a vertical rotor. IN Western Europe however, the Persian mill was quickly improved into a more efficient type of windmill having a horizontal axis of rotation, a wind turbine. Researchers of the history of wind energy note that in a short period of time, windmills with a horizontal axis of rotation almost completely replaced mills with a vertical axis from Europe.
The complexity of the design of a windmill with a horizontal axis was explained by greater operational efficiency. The British mast windmill is a triumph of engineering and the most complex mechanism at the beginning of the Industrial Revolution.
Windmills, developing intensively from the 12th to the 19th centuries, reached a certain perfection. The power of these mills was equal to 25-35 kW.
The industrial revolution in the form of the creation of steam engines and the reduction in the cost of coal led to the displacement of units using wind energy. One of the most interesting phenomena in the history of wind energy, which authors often write about, is the American pumping unit. Such installations are distinguished by a multi-blade rotor, a simple wind orientation system and the possibility of automatic autonomous operation.
The Halladay Standard installation was the very first to achieve real commercial success. The next most famous type of wind pump units are Eclipse rigid rotor units. The third step on the path of American wind pump installations was made in 1888 by The Aermotor company. These wind turbines were made of metal, and their large-scale production significantly reduced their cost.
A revolutionary innovation was the idea of stamping blades from tin. The stamped blades were characterized by a certain geometry and were installed at the desired angle. At high wind speeds, the rotor located behind the stand “floated” due to the connection on the hinges. It should be noted that these installations were made entirely of metal, from the point of view of design, economics and production efficiency they were executed optimally.
Despite significant rural electrification, these windmills remain quite common in many countries.
The total number of these units is over a million (mostly multi-blade units with a wheel diameter of 2.5 m) and the total power is 250 MW.
Over the past 50 years, wind energy technology has made powerful technological leaps, increasing the efficiency of windmills almost tenfold.
At the end of the 19th century, the idea of using wind energy to produce direct electric current arose. The need for such installations was great, so a number of experiments were carried out in different countries. In the literature you can find descriptions of two very different wind turbines, which were among the very first in generating electricity. The first of them is the Brush wind turbine, its power is 12 kW, it generated D.C. for recharging batteries. Overall, the system operated automatically for 20 years and required virtually no maintenance.
The Brush Windmill occupies an important place in the history of wind energy development. First of all, she was big. Secondly, it used a two-stage overdrive belt transmission, the gear ratio of which was 50:1, and the generator had a rotation speed of 500 rpm. This was the first attempt to combine the well-developed windmill system with electrical technology. The installation at the same time showed that multi-bladed wind turbines are very slow and inefficient at generating energy.
The next step in the transition from windmills to wind power plants was taken by Paul Lacourt in Denmark at the beginning of the previous century. He was the first to create a wind tunnel and use the airfoil in wind turbines.
By 1910, approximately one hundred of these wind turbines with a capacity of 5-25 kW were operating in rural Denmark. In the 20-30s, commercial copies of small wind turbines used to recharge batteries appeared in the USA, and they became widespread.
The Jacobs Wind Electric three-blade wind turbine, with blades with an aerodynamic profile, rotated a generator with a power of 3 kW at a voltage of 110 V. It was at the stage of development of wind turbines small sizes To charge the batteries, the problem of the optimal number of blades for the turbine arose. Two-blade wind turbines experienced significant vibration when the wind direction changed, while wind turbines with three blades did not have this problem. This type of wind turbine has been adopted by modern designs almost without changes.
In 1925, a new type of rotor was developed - the Savonius rotor, which was named after its creator, engineer from Finland S. Savonius. The advantages of this type of rotor are a high starting torque and the ability to receive wind from all sides; the disadvantages are a low wind energy processing factor and low speed, and a large mass of the structure.
In the 30s of the previous century, a new type of wind turbine was formed - a vertical wind turbine, proposed by F. Darrieus. The Darrieus rotor had two or three curved blades fixed at the bottom and top of the central column; it could process wind from all directions. This type of wind turbine was almost never used until the early 1970s, when wind turbines with a Darrieus rotor began to be explored in Canada and then in some other countries.
Evolution of windmills
In some countries, research and development activities in the field of wind energy development increased rapidly from the 1940s to the 1960s. But then prices for fossil fuels dropped significantly and, in terms of the cost of electrical energy, wind power plants no longer competed with thermal power plants. During this time, commercial wind energy was barely developed. Experimental models were developed, for example, a wind farm in Kursk.
In the early 1970s, the next rise of wind energy began, which was primarily due to the well-known energy crisis. At this time, the governments of most countries launched large-scale development programs windmills. The development of technologies according to these programs, design work and experiments had to be carried out in constant interaction.
Plans included the formation of three generations of experimental units. The very first generation made it possible to obtain basic data and developments to create a clear concept of wind energy. The second generation was needed to gain practical experience in producing windmills. And the third generation could bring the level of efficiency and reliability of wind turbines to commercial use. These series of wind turbines were intended to advance wind technology to the point where the commercial risk was small enough to attract significant commercial capital.
Research was divided into two directions: wind turbines with a vertical axis and wind turbines with a horizontal axis of rotation. In 1974, the Federal Wind Energy Development Program was created in the USA, according to which experimental prototypes with codes MOD-1, MOD-2, MOD-3, MOD-O, MOD-OA were developed. In Europe the largest and interesting projects is Growian, with a capacity of 3 MW (Germany, 1983), LS-1 3 MW (Great Britain, 1987) and some others. The German project Growian is considered the largest wind turbine ever built: a turbine with a diameter of 100 m, a tower with a height of 100 m. This wind turbine was the first to operate with a variable rotation speed, wind turbine and had an asynchronized synchronous generator.
Too many new products caused many problems in the operation of the windmill, but this wind turbine made a significant contribution to the awareness of the problems of other units.
Mills.Windmills, history, types and designs. - part 5.Sea view with windmill on the shore
Windmill- an aerodynamic mechanism that performs mechanical work due to wind energy captured by the wings of the mill. Most known application windmills are used for grinding flour. For a long time, windmills, along with water mills, were the only machines used by mankind. Therefore, the use of these mechanisms was different: as a flour mill, for processing materials (sawmill) and as a pumping or water-lifting station. With the development in the 19th century. steam engines, the use of mills gradually began to decline. The “classic” windmill with a horizontal rotor and elongated quadrangular wings is a widespread landscape element in Europe, in the windy, flat northern regions, as well as on the coast Mediterranean Sea. Asia is characterized by other designs with a vertical rotor placement. Presumably the oldest mills were common in Babylon, as evidenced by the code of King Hammurabi (circa 1750 BC). The description of the organ powered by the windmill is the first documented evidence of the use of wind to power the mechanism. It belongs to the Greek inventor Heron of Alexandria, 1st century AD. e. Persian mills are described in reports of Muslim geographers in the 9th century; they differ from Western ones in their design with a vertical axis of rotation and perpendicular wings, blades or sails. The Persian mill has blades on the rotor, arranged similarly to the paddle wheel blades on a steamship, and must be enclosed in a shell covering part of the blades, otherwise the wind pressure on the blades will be equal on all sides and, since the sails are rigidly connected to the axle, the mill will not rotate. Another type of mill with a vertical axis of rotation is known as a Chinese mill or Chinese windmill.
Chinese mill.
The design of the Chinese mill differs significantly from the Persian one by using a freely turning, independent sail. Windmills with a horizontal rotor orientation have been known since 1180 in Flanders, South-East England and Normandy. In the 13th century, mill designs appeared in the Holy Roman Empire in which the entire building turned towards the wind.
Bruegel the Elder. Jan (Velvet) Landscape with a windmill
This state of affairs existed in Europe until the advent of internal combustion engines and electric motors in the 19th century. Water mills were common mainly in mountainous areas with fast rivers, and wind - in flat, windy areas. The mills belonged to the feudal lords on whose land they were located. The population was forced to look for so-called forced mills to grind the grain that was grown on this land. Combined with bad road network this led to local economic cycles in which the mills were involved. With the lifting of the ban, the public was able to choose the mill of their choice, thus stimulating technological progress and competition. IN late XVI century in the Netherlands, mills appeared in which only the tower turned towards the wind. Until the end of the 18th century, windmills were widespread throughout Europe - wherever the wind was strong enough. Medieval iconography clearly shows their prevalence.
Jan Brueghel the Elder, Jos de Momper. Life in the field.Prado Museum(at the top right of the picture behind the field is a windmill).
They were mainly found in the windy northern regions of Europe, large parts of France, the Low Countries, where coastal areas once had 10,000 windmills, Great Britain, Poland, the Baltics, northern Russia and Scandinavia. Other European regions had only a few windmills. In countries Southern Europe(Spain, Portugal, France, Italy, Balkans, Greece), typical tower mills were built, with a flat conical roof and, as a rule, a fixed orientation.When the pan-European economic boom occurred in the 19th century, there was also a major growth in the milling industry. With the emergence of many independent craftsmen, there was a one-time increase in the number of mills.
In the first type, the mill barn rotated on a pillar dug into the ground. The support was either additional pillars, or a pyramidal log cage, cut into pieces, or a frame.
The principle of tent mills was different
Tent mills:
a - on a truncated octagon; b - on a straight octagon; c - figure eight on the barn.
- their lower part in the form of a truncated octagonal frame was motionless, and the smaller upper part rotated with the wind. And this type had many variants in different areas, including tower mills - four-wheel, six-wheel and eight-wheel.
All types and variants of mills amaze with precise design calculations and the logic of cuttings that withstood high-power winds. Folk architects also paid attention appearance these are the only vertical economic structures, the silhouette of which played a significant role in the ensemble of villages. This was expressed in the perfection of proportions, and in the grace of carpentry, and in the carvings on pillars and balconies.
Description of the designs and operating principles of mills.
Stolbovki The mills are named because their barn rests on a pillar dug into the ground and covered on the outside with a log frame. It contains beams that keep the post from moving vertically. Of course, the barn rests not only on a pillar, but on a log frame (from the word cut, logs cut in not tightly, but with gaps).
Schematic diagram post mills.
On top of such a ridge, an even round ring is made of plates or boards. The lower frame of the mill itself rests on it.
The rows of pillars can be of different shapes and heights, but not higher than 4 meters. They can rise from the ground immediately in the form of a tetrahedral pyramid or first vertically, and from a certain height they turn into a truncated pyramid. There were, although very rarely, mills on a low frame.
Jan van Goyen. Windmill by the river(here is a typical post or trestle).
Jan van Goyen Scene on ice nearDordrecht(another post - a gantry in the distance on a hill near the canal).
Base tent It can also be different in shape and design. For example, a pyramid may start at ground level, and the structure may not be a log structure, but a frame one. The pyramid can rest on a frame quadrangle, and can be attached to it utility rooms, vestibule, miller's room, etc.
Salomon van Ruysdael View of Deventer from the northwest.(here you can see both the tent and the pillars).
The main thing in mills is their mechanisms.IN tents the internal space is divided by ceilings into several tiers. Communication with them goes along steep attic-type stairs through hatches left in the ceilings. Parts of the mechanism can be located on all tiers. And there can be from four to five. The core of the tent is a powerful vertical shaft, piercing the mill right through to the “cap”. It rests on a metal bearing fixed in a beam that rests on a block frame. The beam can be moved in different directions using wedges. This allows you to give the shaft a strictly vertical position. The same can be done using the top beam, where the shaft pin is embedded in a metal loop.In the lower tier, a large gear with cam-teeth is placed on the shaft, fixed along the outer contour of the round base of the gear. During operation, the movement of the large gear, multiplied several times, is transmitted to the small gear or lantern of another vertical, usually metal shaft. This shaft pierces the stationary lower millstone and rests against a metal bar on which the upper movable (rotating) millstone is suspended through the shaft. Both millstones are covered with a wooden casing on the sides and top. The millstones are installed on the second tier of the mill. The beam in the first tier, on which a small vertical shaft with a small gear rests, is suspended on a metal threaded pin and can be slightly raised or lowered using a threaded washer with handles. With it, the upper millstone rises or falls. This is how the fineness of grain grinding is adjusted.From the millstone casing, a blind plank chute with a board latch at the end and two metal hooks on which a bag filled with flour is hung is slanted downwards.A jib crane with metal gripping arcs is installed next to the millstone block.
Claude-Joseph Vernet Construction of a big road.
With its help, the millstones can be removed from their places for forging.Above the millstone casing, a grain-feeding hopper rigidly attached to the ceiling descends from the third tier. It has a valve that can be used to shut off the grain supply. It has the shape of an overturned truncated pyramid. A swinging tray is suspended from below. For springiness, it has a juniper bar and a pin lowered into the hole of the upper millstone. A metal ring is installed eccentrically in the hole. The ring can also have two or three oblique feathers. Then it is installed symmetrically. The pin with the ring is called the shell. Running along the inner surface of the ring, the pin constantly changes position and rocks the slanted tray. This movement pours the grain into the jaw of the millstone. From there it falls into the gap between the stones, is ground into flour, which goes into the casing, from it into closed tray and a bag.
Willem van Drielenburgh Landscape with a viewDordrecht(tents...)
The grain is poured into a hopper embedded in the floor of the third tier. Bags of grain are fed here using a gate and a rope with a hook. The gate can be connected and disconnected from a pulley mounted on a vertical shaft. This is done from below using a rope and a lever. A hatch is cut into the floor boards, covered with inclined double-leaf doors. The bags , passing through the hatch, they open the doors, which then slam shut randomly. The miller turns off the gate, and the bag ends up on the hatch covers. The operation is repeated.In the last tier, located in the “head”, another, small gear with beveled cam-teeth is installed and secured on the vertical shaft. It causes the vertical shaft to rotate and starts the entire mechanism. But it is made to work by a large gear on a “horizontal” shaft. The word is in quotation marks because in fact the shaft lies with a slight downward slope of the inner end.
Abraham van Beveren (1620-1690) Marine scene
The pin of this end is enclosed in a metal shoe of a wooden frame, the base of the cap. The raised end of the shaft, extending outward, rests quietly on a “bearing” stone, slightly rounded at the top. The shaft is embedded in this place metal plates, protecting the shaft from rapid erasure.Two mutually perpendicular bracket beams are cut into the outer head of the shaft, to which other beams are attached with clamps and bolts - the basis of the lattice wings. The wings can receive the wind and rotate the shaft only when the canvas is spread out on them, usually rolled into bundles during rest, not working hours. The surface of the wings will depend on the strength and speed of the wind.
Schweickhardt, Heinrich Wilhelm (1746 Hamm, Westphalia - 1797 London) Fun on a frozen canal
The "horizontal" shaft gear has teeth cut into the side of the circle. It is hugged on top by a wooden brake block, which can be released or tightened with the help of a lever. Sharp braking in strong and gusty winds will cause high temperature when rubbing wood against wood, and even smoldering. This is best avoided.
Corot, Jean-Baptiste Camille Windmill.
Before operation, the wings of the mill should be turned towards the wind. For this purpose there is a lever with struts - a “carriage”.
Small columns of at least 8 pieces were dug around the mill. A “drive” was attached to them and was attached with a chain or thick rope. With the strength of 4-5 people, even if the upper ring of the tent and parts of the frame are well lubricated with grease or something similar (previously they were lubricated with lard), it is very difficult, almost impossible, to turn the “cap” of the mill. “Horsepower” doesn’t work here either. Therefore, they used a small portable gate, which was alternately placed on posts with its trapezoidal frame, which served as the basis of the entire structure.
Bruegel the Elder. Jan (Velvet). Four windmills
A block of millstones with a casing with all the parts and details located above and below it was called in one word - postav. Usually small and medium-sized windmills were made “in one batch.” Large wind turbines could be built with two stages. There were windmills with “pressures” on which flax or hemp seed to obtain the appropriate oil. Waste - cake - was also used in household. “Saw” windmills seemed to never occur.
Bout, Pieter Village square
The sun turned red in the evening.
The fog is already spreading over the river.
The ugly wind has calmed down,
Just the mill flapping its wings.
Wooden, black, old -
Good for no one,
Tired of worries, tired of troubles,
And, like the wind in a field, free.
Windmills are designed to produce flour. They use wind energy. The first mentions of windmills date back to the Middle Ages. Although it is believed that the first windmills appeared before our era. The invention of the windmill is directly related to the development of technology based on the invention of the wheel. Windmills of the simplest design are mounted on trestles, which is why they are known as trestle mills.
The peculiarity of such a mill is that it can rotate around its axis. This is necessary so that the wings of the mill are always turned towards the wind, which often changes its direction. A vertical fixed oak pillar, about 6 meters long. The lower, square part of the column, about 60 centimeters thick, has cross-shaped sockets at the end, which are placed on beams connected at right angles. Under the beams, in the direction of their diverging ends, stone walls or, in other words, a foundation are placed. The mills were turned with the help of animals, which were tied to levers and forced to walk in a circle.
In the so-called Dutch mills, not the entire mill rotates, but only its upper part, where the shaft with wings is located. The buildings of such mills are made of brick or stone, in the form of a truncated cone, or they are made of wood, in the form of a truncated octagonal pyramid, or sometimes Bottom part The structure is made of stone and the top is made of wood. In this mill, a shaft with wings inclined towards the horizon rotates together with the roof in the direction of the wind, so that the wings are located against the wind and receive a rotational movement, which is transmitted through conical wheels to a vertical shaft that imparts movement to the milling machines. A cylindrical wheel is attached to the shaft, which engages with the wheels on the spindles of four millstones.
From the same shaft, a vertical shaft receives movement, and from this latter, through a conical wheel, a horizontal shaft is driven, imparting movement to other shafts that drive screws and prismatic sieves. The ground product, upon exiting the millstones, first enters the grooves of the screws and then is conveyed to the sieves by the screws. The sifted product is collected in bags attached to pipes. To lift the grains and residues to be ground, there is a lifting platform moving along the guide posts. The platform is connected to a rope wound around the shaft when the flat rim of the wheel is pressed against the lower edge of the wheel rim, which is raised along with the shaft by means of a special lever. Instead of lifting the bags on a platform, they can be lifted directly by a rope wound around a shaft.
The wings of windmills consist of flaps attached to the shaft, feathers or brooms connected to the flaps, and sails or shields laid on the brooms. To rotate the wings, their surface on which the air presses is located obliquely to the direction of wind movement.
American windmills are significantly different from those previously considered: instead of 4-6 separate wings of previous devices, they use wings in the form of narrow slats arranged in the form of a ring, the inner diameter of which is about 1/3 of its outer diameter. Such a ring, fixed on an axis, horizontal or slightly inclined to the horizon, imparts rotational motion to it and, unlike a shaft with wings, can be called a wind wheel. Like Dutch mills, American windwheels are equipped with devices for automatic installation them against the wind and for automatically adjusting them with changing wind strength, but the mechanisms for this purpose are particularly original and simple, facilitating their execution, and also, which is very important, these designs do not require hollow shafts, as a result of which the diameter of the journals is reduced and work is saved , spent to overcome friction on their surfaces.
One of the first stable sources of energy mastered by man was wind.
Thanks to the wind, great geographical discoveries occurred, humanity gained the opportunity to travel, irrigate fields, grind grain, and, finally, it learned to convert wind into clean energy in the form of electricity.
If Noah's Ark existed, it probably sailed.
Energy “from the mouth of Aeolus” (Fig. 4.1) was first used on sailing ships, which served as the main vehicle for transporting goods along the Nile in ancient Egypt.
The ancient Greeks attributed the invention of the sail to the same distant times when fire was mastered and wild animals were tamed. In the long series of benefits with which Prometheus blessed the human race, Aeschylus also mentions the sail:
“He equipped the ships with flaxen wings, and boldly drove them across the seas.”
It is known for certain from old documents that already four thousand years ago, the brave Phoenicians who lived on the eastern shore of the Mediterranean Sea intensively used sails. It was primitive and imperfect, but with its help the Phoenicians sailed to the mouth of the Nile, where they organized brisk trade with the Egyptians, and two and a half thousand years ago they even made the first voyage around Africa described in history. Oceans opened up for people who mastered wind energy. The sail is associated with the beginning of the development of new lands and new markets. Wind energy contributed to the development of civilization.
The power of the wind has been valued and used since ancient times in many countries. And although wind energy has never been used as widely on land as at sea, it is nevertheless reliably known about the existence of wind wheels thousands of years BC. For example, in the Alexandria region there are remains of windmills that are at least three thousand years old. The Babylonians used them to drain swamps; in Egypt, the Middle East, and Persia they built wind power lifts and mills.
200 years BC in Persia, simple windmills with a vertical axis of rotation were used to grind grain, and even earlier they were used in China.
Mills of this type rotated around a vertical axis like a spinning top or a toy gyroscope. Ancient Persian windmills were made by attaching bundles of reeds to wooden frame, which rotated when the wind blew. The wall surrounding the mill directed the wind towards the frame (Fig. 4.2).
There is a recorded mention of a windmill in Iran in 644, when in the indictment against a certain Abu Lulua, who killed Caliph Umar ibn al-Qattab, he is called “the builder of windmills.” A little over 200 years later, windmills appear in the town of Sietek on the border between Iran and Afghanistan.
The use of mills with a vertical axis of rotation subsequently became widespread in the countries of the Middle East. Later, a mill with a horizontal axis of rotation was developed, consisting of ten wooden posts equipped with transverse sails. This primitive type of windmill is still used today in many countries around the Mediterranean Sea.
In the 11th century, windmills were widely used in the Middle East and came to Europe when the Crusaders returned. The first mention of a windmill in Europe, first in France, dates back to 1105: the archives preserved a permit issued to a certain monastery to build a mill. The French chronicles of 1180 and the English chronicles of 1190 already speak directly about working windmills, but not at all about those with which the cunning hidalgo Don Quixote of La Mancha subsequently fought! These were clumsy structures with blades rotating in a horizontal plane, mounted on a wooden body. According to the principle of operation, English and French mills were of the same type. In Germany, the first mill was built in 1393. From Germany they spread to other countries.
The windmill, through the work of many generations, was improved and acquired a more familiar appearance. It turned out to be much simpler than the water one and much cheaper. Its main drawback was the instability of the energy carrier – wind.
The wind is a capricious assistant, as it quickly and constantly changes its direction. This problem has long prevented the use of wind power. Finally, in the 13th century, a solution was found - wind
a wheel that turned with the help of a primitive lever and thus the wings were always exposed to the wind. A manuscript from 1270 called the Watermill Psalter contains an image of one of the first windmills.
A representative of an improved design in this direction is the “Bock” windmill (Fig. 4.3). The mill housing, rotating on a vertical axle, was located on a wooden lower frame, the so-called “Bock”. With the help of an outwardly inclined beam, the body of the mill was rotated and the wings were installed in the direction of the wind. These mills have been used to grind grain for hundreds of years. They were reliable, simple and durable. If necessary, millers could manually on our own repair them. WITH economic point In view of the matter, using a Bock windmill was so beneficial that the authorities could not stand aside and began to put forward their demands. In the middle of the century, the miller had to pay his feudal lord a tenth of the proceeds from the mill. The Bishop of Utrecht even publicly declared that all the winds and breezes of the province were his personal property. True, it has not reached our days whether the wind also blew when its owner ordered it. But Bock mills were used everywhere.
A
b
Rice. 4.3. General form(a) and section (b) of a “Bock” windmill
In the 14th century, the Dutch became the leaders in improving the design of windmills, since in Holland (the Netherlands) these mills served as the basis for the energy base. We can say that the country owes its very existence to them: after all, most of the territory of the Netherlands (“low-lying country” in literal translation) lies below sea level. It was wind engines that made it possible to carry out grandiose work on draining swamps and pumping out water. The power of the wind was contrasted with the power of another element - the sea, which constantly threatened to flood the land of the small country.
The Dutch made many improvements in the design of windmills. The mills, as a rule, had four wooden wings of a lattice structure with rough canvas stretched over them. By folding or unfurling these “sails,” people respectively reduced or increased the area of the wings and thus converted the variable force of the wind into a relatively uniform stroke of the wind engine. Some mills had up to eight wings (Fig. 4.4, 4.5).
The wings of some windmills, made entirely of wood, looked like blinds. Instead of canvas, they used movable plates to regulate the wind pressure. In the 16th century, primitive cross sails on wooden shelves gave way to sails fixed on wooden blocks on both sides of the swing (Fig. 4.6).
Later, to improve the aerodynamic shape of the wings, bars were attached to the trailing edge. In more modern designs the sails were replaced with thin sheet metal, steel swings and various types of louvres and flaps were used to regulate the speed of the wind wheel at high wind speeds.
Wind wheels worked on the same principle as water wheels, and therefore had a very big sizes: wingspan up to 28 m, wing width 2 m, and the height of the entire tower structure of the mill reached 30 m. Large windmills at high wind speeds could develop power up to 66 kW.
Windmills, like watermills, did not remain simply devices for grinding grain for long. In 1582, the first oil mill using wind power was built in Holland, in 1586 - the first paper mill, which met the increased demands on paper caused by the invention of the printing press, and in 1592, sawmills appeared to produce timber using wind energy. The mills also ground snuff and spices and wove linen.
The economic prosperity of Holland, where Peter I (1672–1725) went to study his wits, in the 16th century was caused precisely by the development of wind energy in this country. The Dutch have successfully moved from the initial use of windmills to drain low-lying coastal lands to their use as a drive for various industries. As a result, Holland became the most energy-equipped country in Europe at that time.
The most successful windmill design was proposed by the Dutchman Jan Andriaanezoon back in the 17th century (later it was called “Dutch” all over the world). With the help of this mill, he drained 27 lakes, earning his compatriots the honorary nickname “Leegwater” - “drainer of waters.”
The maximum distribution of windmills in pre-industrial Europe was observed in the 1700s, when wooden giants rhythmically rotated their wings on the plains of Germany, Italy, Russia, Ukraine, Spain and, of course, Holland - the classic country of windmills. In the 30s of the 18th century, 1,200 wind turbines operated in Holland, which protected 2/3 of the country from turning back into swamps. And by the end of the 19th century, there were over 10,000 of them in Holland (in 1923 - only 2,500, and in our time - barely a thousand), and in small Denmark - 30,000 for domestic purposes and 3,000 wind turbines that were used in industry.