The process of inventing a steam engine, as is often the case in technology, stretched out for almost a century, so the choice of a date for this event is rather arbitrary. However, no one denies that the breakthrough that led to the technological revolution was carried out by the Scot James Watt.

People have thought about using steam as a working fluid since ancient times. However, only at the turn of the XVII-XVIII centuries. managed to find a way to produce useful work with the help of steam. One of the first attempts to put steam at the service of man was made in England in 1698: the inventor Savery's machine was designed to drain mines and pump water. True, Savery's invention was not yet an engine in the full sense of the word, since, apart from a few manually opened and closed valves, it had no moving parts. Savery's machine worked as follows: first, the sealed tank was filled with steam, then the outer surface of the tank was cooled. cold water, causing the steam to condense and create a partial vacuum in the tank. After that, water - for example, from the bottom of the mine - was sucked into the tank through the intake pipe and, after the next portion of steam was admitted, was thrown out.

The first steam engine with a piston was built by the Frenchman Denis Papin in 1698. Water was heated inside a vertical cylinder with a piston, and the resulting steam pushed the piston up. As the steam cooled and condensed, the piston was pushed down by atmospheric pressure. Through a system of blocks, Papin's steam engine could drive various mechanisms, such as pumps.

A more perfect machine was built in 1712 by the English blacksmith Thomas Newcomen. As in Papin's machine, the piston moved in a vertical cylinder. Steam from the boiler entered the base of the cylinder and lifted the piston up. When cold water was injected into the cylinder, the steam condensed, a vacuum formed in the cylinder, and under the influence of atmospheric pressure the piston fell down. This return stroke removed the water from the cylinder and, by means of a chain connected to a rocker, moving like a swing, raised the pump rod upwards. When the piston was at the bottom of its stroke, steam entered the cylinder again, and with the help of a counterweight mounted on the pump rod or on the rocker, the piston rose to its original position. After that, the cycle was repeated.

The Newcomen machine was widely used in Europe for over 50 years. In the 1740s, a machine with a cylinder 2.74 m long and 76 cm in diameter did in one day the work that a team of 25 people and 10 horses, working in shifts, did in a week. And yet its efficiency was extremely low.

The most striking industrial revolution manifested itself in England, primarily in the textile industry. The discrepancy between the supply of fabrics and the rapidly increasing demand attracted the best design minds to the development of spinning and weaving machines. The history of English technology forever included the names of Cartwright, Kay, Crompton, Hargreaves. But the spinning and weaving machines they created needed a qualitatively new, universal engine that would continuously and evenly (which the water wheel could not provide) would drive the machines into unidirectional rotational motion. It was here that the talent of the famous engineer, the "wizard of Greenock" James Watt, appeared in all its splendor.

Watt was born in the Scottish town of Greenock in the family of a shipbuilder. Working as an apprentice in workshops in Glasgow, in the first two years, James acquired the qualifications of an engraver, a master in the manufacture of mathematical, surveying, optical instruments, and various navigational instruments. On the advice of his uncle, the professor, James entered the local university as a mechanic. It was here that Watt began working on steam engines.

James Watt was trying to improve Newcomen's steam-atmospheric machine, which, in general, was only good for pumping water. It was clear to him that the main drawback of Newcomen's machine was the alternating heating and cooling of the cylinder. In 1765, Watt came up with the idea that the cylinder could remain hot all the time if, before condensation, the steam was diverted into a separate reservoir through a pipeline with a valve. In addition, Watt made several more improvements that finally turned the steam-atmospheric engine into a steam engine. For example, he invented a hinge mechanism - "Watt's parallelogram" (so called because part of the links - the levers that make up its composition forms a parallelogram), which converted the reciprocating movement of the piston into the rotational movement of the main shaft. Now the looms could run continuously.

In 1776 Watt's machine was tested. Its efficiency turned out to be twice that of Newcomen's machine. In 1782, Watt created the first universal steam engine double action. Steam entered the cylinder alternately from one side of the piston, then from the other. Therefore, the piston made both a working and a reverse stroke with the help of steam, which was not in old cars. Since the piston rod in a double-acting steam engine performed a pulling and pushing action, the old drive system of chains and rocker arms, which responded only to traction, had to be redone. Watt developed a linkage system and used a planetary mechanism to convert the reciprocating motion of a piston rod into rotational motion, using a heavy flywheel, a centrifugal speed controller, a disk valve, and a manometer to measure steam pressure. The “rotary steam engine” patented by Watt was first widely used in spinning and weaving mills, and later in other industrial enterprises. The Watt engine was suitable for any car, and the inventors of self-propelled mechanisms were not slow to take advantage of this.

Watt's steam engine was truly the invention of the century, marking the beginning of the industrial revolution. But the inventor did not stop there. Neighbors watched with surprise more than once as Watt drove horses across the meadow, pulling specially selected weights. So there was a unit of power - horsepower, which later received universal recognition.

Unfortunately, financial difficulties forced Watt, already in adulthood, to conduct geodetic surveys, work on the construction of canals, build ports and marinas, and finally enter into an economically enslaving alliance with entrepreneur John Rebeck, who soon suffered a complete financial collapse.

STEAM ROTARY ENGINE and STEAM AXIAL PISTON ENGINE

The rotary steam engine (rotary type steam engine) is a unique power machine, the development of production of which has not yet received due development.

On the one hand, various designs rotary engines existed in the last third of the 19th century and even worked well, including for driving dynamos in order to generate electrical energy and supply all kinds of objects. But the quality and accuracy of manufacturing such steam engines (steam engines) was very primitive, so they had low efficiency and low power. Since then, small steam engines have become a thing of the past, but along with really inefficient and unpromising reciprocating steam engines, rotary steam engines that have good prospects have also become a thing of the past.

The main reason is that at the level of technology of the late 19th century, it was not possible to make a really high-quality, powerful and durable rotary engine.
Therefore, of the whole variety of steam engines and steam engines, only steam turbines of enormous power (from 20 MW and above) have successfully and actively survived to our time, which today account for about 75% of electricity generation in our country. More steam turbines high power provide energy from nuclear reactors in combat missile-carrying submarines and on large Arctic icebreakers. But that's all huge machines. Steam turbines dramatically lose all their efficiency when they are reduced in size.

…. That is why power steam engines and steam engines with power below 2000 - 1500 kW (2 - 1.5 MW), which would effectively operate on steam obtained from the combustion of cheap solid fuel and various free combustible waste, are not now in the world.
It is in this empty field of technology today (and an absolutely bare, but very needy commercial niche), in this market niche of low-power power machines, that steam rotary engines can and should take their very worthy place. And the need for them only in our country is tens and tens of thousands ... Especially small and medium-sized power machines for autonomous power generation and independent power supply are needed by small and medium-sized enterprises in areas remote from large cities and large power plants: - at small sawmills, remote mines, in field camps and forest plots, etc., etc.
…..

..
Let's take a look at the factors that make rotary steam engines better than their closest cousins, the steam engines in the form of reciprocating steam engines and steam turbines.
… — 1) Rotary engines are power machines of volumetric expansion - like piston engines. Those. they have a low steam consumption per unit of power, because steam is supplied to their working cavities from time to time, and in strictly metered portions, and not in a constant plentiful flow, as in steam turbines. That is why steam rotary engines are much more economical than steam turbines per unit of output power.
— 2) Rotary steam engines have a shoulder for applying the acting gas forces (torque shoulder) significantly (many times) more than reciprocating steam engines. Therefore, the power developed by them is much higher than that of steam piston engines.
— 3) Steam rotary engines have a much greater power stroke than reciprocating steam engines, i.e. have the ability to convert most of the internal energy of steam into useful work.
— 4) Steam rotary engines can operate efficiently on saturated (wet) steam, without difficulty allowing the condensation of a significant part of the steam with its transition to water directly in the working sections of the steam rotary engine. This also increases the efficiency of the steam power plant using a steam rotary engine.
— 5 ) Steam rotary engines operate at a speed of 2-3 thousand revolutions per minute, which is the optimal speed for generating electricity, in contrast to the too low-speed piston engines (200-600 revolutions per minute) of traditional locomotive-type steam engines, or from too high-speed turbines (10-20 thousand revolutions per minute).

At the same time, steam rotary engines are technologically relatively easy to manufacture, which makes their manufacturing costs relatively low. In contrast to the extremely expensive steam turbines to manufacture.

SO, SUMMARY OF THIS ARTICLE - a steam rotary engine is a very efficient steam power machine for converting steam pressure from the heat of burning solid fuel and combustible waste into mechanical power and into electrical energy.

The author of this site has already received more than 5 patents for inventions on various aspects of the designs of steam rotary engines. A number of small rotary engines with a power of 3 to 7 kW were also produced. Now we are designing steam rotary engines with power from 100 to 200 kW.
But rotary engines have a "generic flaw" - a complex system of seals, which for small engines are too complex, miniature and expensive to manufacture.

At the same time, the author of the site is developing steam axial piston engines with opposite - oncoming piston movement. This arrangement is the most energy-efficient variation in terms of power from all possible schemes for the use of a piston system.
These motors in small sizes are somewhat cheaper and simpler than rotary motors and the seals in them are used the most traditional and simplest.

Below is a video using a small axial piston boxer engine with opposite pistons.

At present, such a 30 kW axial piston boxer engine is being manufactured. The engine resource is expected to be several hundred thousand engine hours, because the steam engine speed is 3-4 times lower than the engine speed internal combustion, in the friction pair "piston-cylinder" - subjected to ion-plasma nitriding in a vacuum environment and the hardness of the friction surfaces is 62-64 HRC units. For details on the process of surface hardening by nitriding, see.

Here is an animation of the principle of operation of such an axial-piston boxer engine, similar in layout, with an oncoming piston movement

A steam engine is a heat engine in which the potential energy of expanding steam is converted into mechanical energy given to the consumer.

We will get acquainted with the principle of operation of the machine using the simplified diagram of Fig. one.

Inside cylinder 2 is a piston 10 which can move back and forth under steam pressure; the cylinder has four channels that can be opened and closed. Two upper steam channels1 And3 are connected by a pipeline to the steam boiler, and through them fresh steam can enter the cylinder. Through the two lower capals 9 and 11, the pair, which has already completed the work, is released from the cylinder.

The diagram shows the moment when channels 1 and 9 are open, channels 3 and11 closed. Therefore, fresh steam from the boiler through the channel1 enters the left cavity of the cylinder and, with its pressure, moves the piston to the right; at this time, the exhaust steam is removed from the right cavity of the cylinder through channel 9. With the extreme right position of the piston, the channels1 And9 are closed, and 3 for the inlet of fresh steam and 11 for the exhaust of exhaust steam are open, as a result of which the piston will move to the left. At the extreme left position of the piston, channels open1 and 9 and channels 3 and 11 are closed and the process is repeated. Thus, a rectilinear reciprocating motion of the piston is created.

To convert this movement into rotational, the so-called crank mechanism is used. It consists of a piston rod - 4, connected at one end to the piston, and at the other, pivotally, by means of a slider (crosshead) 5, sliding between the guide parallels, with a connecting rod 6, which transmits movement to the main shaft 7 through its knee or crank 8.

The amount of torque on the main shaft is not constant. Indeed, the strengthR , directed along the stem (Fig. 2), can be decomposed into two components:TO directed along the connecting rod, andN , perpendicular to the plane of the guide parallels. The force N has no effect on the movement, but only presses the slider against the guide parallels. StrengthTO is transmitted along the connecting rod and acts on the crank. Here it can again be decomposed into two components: the forceZ , directed along the radius of the crank and pressing the shaft against the bearings, and the forceT perpendicular to the crank and causing the shaft to rotate. The magnitude of the force T will be determined from the consideration of the triangle AKZ. Since the angle ZAK = ? + ?, then

T = K sin (? + ?).

But from the OCD triangle the strength

K= P/ cos ?

that's why

T= psin( ? + ?) / cos ? ,

During the operation of the machine for one revolution of the shaft, the angles? And? and strengthR are continuously changing, and therefore the magnitude of the torsional (tangential) forceT also variable. To create a uniform rotation of the main shaft during one revolution, a heavy flywheel is mounted on it, due to the inertia of which a constant angular speed of rotation of the shaft is maintained. In those moments when the powerT increases, it cannot immediately increase the speed of rotation of the shaft until the flywheel accelerates, which does not happen instantly, since the flywheel has a large mass. At those moments when the work produced by the twisting forceT , becomes less work Because of the resistance forces created by the consumer, the flywheel, again, due to its inertia, cannot immediately reduce its speed and, giving up the energy received during its acceleration, helps the piston overcome the load.

At the extreme positions of the piston angles? +? = 0, so sin (? + ?) = 0 and, therefore, T = 0. Since there is no rotational force in these positions, if the machine were without a flywheel, sleep would have to stop. These extreme positions of the piston are called dead positions or dead points. The crank also passes through them due to the inertia of the flywheel.

In dead positions, the piston is not brought into contact with the cylinder covers, a so-called harmful space remains between the piston and the cover. The volume of harmful space also includes the volume of steam channels from the steam distribution organs to the cylinder.

StrokeS called the path traveled by the piston when moving from one extreme position to another. If the distance from the center of the main shaft to the center of the crank pin - the radius of the crank - is denoted by R, then S = 2R.

Cylinder displacement V h called the volume described by the piston.

Typically, steam engines are double (double-sided) action (see Fig. 1). Sometimes single-acting machines are used, in which steam exerts pressure on the piston only from the side of the cover; the other side of the cylinder in such machines remains open.

Depending on the pressure with which the steam leaves the cylinder, the machines are divided into exhaust, if the steam escapes into the atmosphere, condensing, if the steam enters the condenser (a refrigerator where reduced pressure is maintained), and heat extraction, in which the steam exhausted in the machine is used for any purpose (heating, drying, etc.)

Steam engines were used as a driving engine in pumping stations, locomotives, on steam ships, tractors, steam cars and others. Vehicle Oh. Steam engines contributed to the widespread commercial use of machines in enterprises and were the energy basis of the industrial revolution of the 18th century. Steam engines were later superseded by internal combustion engines, steam turbines, electric motors, and nuclear reactors, which are more efficient.

Steam engine in action

invention and development

The first known device powered by steam was described by Heron of Alexandria in the first century, the so-called "Heron's bath" or "aeolipil". The steam coming out tangentially from the nozzles fixed on the ball made the latter rotate. It is assumed that the conversion of steam to mechanical movement was known in Egypt during the period of Roman rule and was used in simple devices.

First industrial engines

None of the described devices has actually been used as a means of solving useful problems. The first steam engine used in production was the "fire engine", designed by the English military engineer Thomas Savery in 1698. Savery received a patent for his device in 1698. It was a reciprocating steam pump, and obviously not very efficient, since the heat of the steam was lost every time the container was cooled, and quite dangerous in operation, because due to the high pressure of the steam, the tanks and engine pipelines sometimes exploded. Since this device could be used both to turn the wheels of a water mill and to pump water out of mines, the inventor called it a "miner's friend."

Then the English blacksmith Thomas Newcomen in 1712 demonstrated his " naturally aspirated engine", which was the first steam engine for which there could be commercial demand. It was an improved Savery steam engine in which Newcomen significantly reduced operating pressure pair. Newcomen may have been based on a description of Papin's experiments held by the Royal Society of London, to which he may have had access through a member of the society, Robert Hooke, who worked with Papin.

Scheme of work steam engine Newcomen.
– Steam is shown in purple, water in blue.
– Open valves are shown in green, closed valves in red

The first application of the Newcomen engine was to pump water from a deep mine. In the mine pump, the rocker was connected to a rod that descended into the mine to the pump chamber. The reciprocating movements of the thrust were transmitted to the piston of the pump, which supplied water to the top. The valves of early Newcomen engines were opened and closed by hand. The first improvement was the automation of the valves, which were driven by the machine itself. Legend tells that this improvement was made in 1713 by the boy Humphrey Potter, who had to open and close the valves; when he got tired of it, he tied the valve handles with ropes and went to play with the children. By 1715, a lever control system was already created, driven by the mechanism of the engine itself.

The first two-cylinder vacuum steam engine in Russia was designed by the mechanic I.I. Polzunov in 1763 and built in 1764 to drive the blower bellows at the Barnaul Kolyvano-Voskresensky factories.

Humphrey Gainsborough built a model condenser steam engine in the 1760s. In 1769, Scottish mechanic James Watt (perhaps using Gainsborough's ideas) patented the first significant improvements to the Newcomen vacuum engine, which made it much more fuel efficient. Watt's contribution was to separate the condensation phase of the vacuum engine in a separate chamber while the piston and cylinder were at steam temperature. Watt added a few more important details to the Newcomen engine: he placed a piston inside the cylinder to expel steam and converted the reciprocating movement of the piston into the rotational movement of the drive wheel.

Based on these patents, Watt built a steam engine in Birmingham. By 1782, Watt's steam engine was more than 3 times as efficient as Newcomen's. The improvement in the efficiency of the Watt engine led to the use of steam power in industry. In addition, unlike the Newcomen engine, the Watt engine made it possible to transmit rotational motion, while in early models of steam engines the piston was connected to the rocker arm, and not directly to the connecting rod. This engine already had the main features of modern steam engines.

A further increase in efficiency was the use of high pressure steam (American Oliver Evans and Englishman Richard Trevithick). R. Trevitik successfully built high-pressure industrial single-stroke engines, known as "Cornish engines". They operated at 50 psi, or 345 kPa (3.405 atmospheres). However, with increasing pressure, there was also a greater danger of explosions in machines and boilers, which initially led to numerous accidents. From this point of view, the most important element of the high-pressure machine was the safety valve, which released excess pressure. Reliable and safe operation began only with the accumulation of experience and the standardization of procedures for the construction, operation and maintenance of equipment.

French inventor Nicolas-Joseph Cugnot demonstrated the first working self-propelled steam vehicle in 1769: the "fardier à vapeur" (steam cart). Perhaps his invention can be considered the first automobile. The self-propelled steam tractor turned out to be very useful as a mobile source of mechanical energy that set in motion other agricultural machines: threshers, presses, etc. In 1788, a steamboat built by John Fitch was already operating a regular service along the Delaware River between Philadelphia (Pennsylvania) and Burlington (state of New York). He lifted 30 passengers on board and went at a speed of 7-8 miles per hour. J. Fitch's steamboat was not commercially successful, as a good overland road competed with its route. In 1802, Scottish engineer William Symington built a competitive steamboat, and in 1807, American engineer Robert Fulton used a Watt steam engine to power the first commercially successful steamboat. On 21 February 1804, the first self-propelled railway steam locomotive, built by Richard Trevithick, was on display at the Penydarren ironworks at Merthyr Tydfil in South Wales.

Reciprocating steam engines

Reciprocating engines use steam power to move a piston in a sealed chamber or cylinder. The reciprocating action of a piston can be mechanically converted into linear motion for piston pumps, or into rotary motion to drive rotating parts of machine tools or vehicle wheels.

vacuum machines

Early steam engines were called at first "fire engines", and also "atmospheric" or "condensing" Watt engines. They worked on the vacuum principle and are therefore also known as "vacuum engines". Such machines worked to drive piston pumps, in any case, there is no evidence that they were used for other purposes. During the operation of a vacuum-type steam engine at the beginning of the steam cycle low pressure is admitted into the working chamber or cylinder. The inlet valve then closes and the steam cools and condenses. In a Newcomen engine, the cooling water is sprayed directly into the cylinder and the condensate escapes into a condensate collector. This creates a vacuum in the cylinder. Atmospheric pressure at the top of the cylinder presses on the piston, and causes it to move down, that is, the power stroke.

Constant cooling and reheating of the working cylinder of the machine was very wasteful and inefficient, however, these steam engines allowed pumping water from a greater depth than was possible before their appearance. A version of the steam engine appeared in the year, created by Watt in collaboration with Matthew Boulton, the main innovation of which was the removal of the condensation process in a special separate chamber (condenser). This chamber was placed in a cold water bath and connected to the cylinder by a tube closed by a valve. A special small vacuum pump (a prototype of a condensate pump) was attached to the condensation chamber, driven by a rocker arm and used to remove condensate from the condenser. The resulting hot water was supplied by a special pump (a prototype of the feed pump) back to the boiler. Another radical innovation was the closure of the upper end of the working cylinder, at the top of which was now low-pressure steam. The same steam was present in the double jacket of the cylinder, supporting it constant temperature. During the upward movement of the piston, this steam was transferred through special tubes to the lower part of the cylinder in order to be condensed during the next stroke. The machine, in fact, ceased to be "atmospheric", and its power now depended on the pressure difference between low-pressure steam and the vacuum that could be obtained. In the Newcomen steam engine, the piston was lubricated with a small amount of water poured on top of it, in Watt's engine this became impossible, since there was now steam in the upper part of the cylinder, it was necessary to switch to lubrication with a mixture of grease and oil. The same grease was used in the cylinder rod stuffing box.

Vacuum steam engines, despite the obvious limitations of their efficiency, were relatively safe, using low-pressure steam, which was quite consistent with the general low level of 18th century boiler technology. The power of the machine was limited by low steam pressure, cylinder size, the rate of fuel combustion and water evaporation in the boiler, and the size of the condenser. The maximum theoretical efficiency was limited by the relatively small temperature difference on either side of the piston; this made vacuum machines intended for industrial use too large and expensive.

Compression

The outlet port of a steam engine cylinder closes somewhat before the piston reaches its end position, leaving some exhaust steam in the cylinder. This means that there is a compression phase in the cycle of operation, which forms the so-called “vapor cushion”, which slows down the movement of the piston in its extreme positions. It also eliminates the sudden pressure drop at the very beginning of the intake phase when fresh steam enters the cylinder.

Advance

The described “vapor cushion” effect is also enhanced by the fact that the intake of fresh steam into the cylinder begins somewhat earlier than the piston reaches its extreme position, that is, there is some advance of the intake. This advance is necessary so that before the piston starts its working stroke under the action of fresh steam, the steam would have time to fill the dead space that arose as a result of the previous phase, that is, the intake-exhaust channels and the volume of the cylinder not used for piston movement.

simple extension

A simple expansion assumes that the steam only works when it expands in the cylinder, and the exhaust steam is released directly into the atmosphere or enters a special condenser. The residual heat of the steam can then be used, for example, to heat a room or a vehicle, as well as to preheat the water entering the boiler.

Compound

During the expansion process in the cylinder of a high-pressure machine, the temperature of the steam drops in proportion to its expansion. Since there is no heat exchange (adiabatic process), it turns out that the steam enters the cylinder at a higher temperature than it leaves it. Such temperature fluctuations in the cylinder lead to a decrease in the efficiency of the process.

One of the methods of dealing with this temperature difference was proposed in 1804 by the English engineer Arthur Wolfe, who patented Wulff high-pressure compound steam engine. In this machine, high-temperature steam from the steam boiler entered the high-pressure cylinder, and then the steam exhausted in it at a lower temperature and pressure entered the low-pressure cylinder (or cylinders). This reduced the temperature drop in each cylinder, which generally reduced temperature losses and improved the overall coefficient useful action steam engine. The low-pressure steam had a larger volume, and therefore required a larger volume of the cylinder. Therefore, in compound machines, the low pressure cylinders had a larger diameter (and sometimes longer) than the high pressure cylinders.

This arrangement is also known as "double expansion" because the expansion of the steam occurs in two stages. Sometimes one high-pressure cylinder was connected to two low-pressure cylinders, resulting in three approximately the same size cylinders. Such a scheme was easier to balance.

Two-cylinder compounding machines can be classified as:

• Cross compound- Cylinders are located side by side, their steam-conducting channels are crossed.
• Tandem compound- Cylinders are arranged in series and use one rod.
• Angle compound- The cylinders are at an angle to each other, usually 90 degrees, and operate on one crank.

After the 1880s, compound steam engines became widespread in manufacturing and transportation, and became virtually the only type used on steamboats. Their use on steam locomotives was not as widespread as they proved to be too complex, partly due to the difficult operating conditions of steam engines in rail transport. Although compound locomotives never became a mainstream phenomenon (especially in the UK, where they were very rare and not used at all after the 1930s), they gained some popularity in several countries.

Multiple expansion

Simplified diagram of a triple expansion steam engine.
High pressure steam (red) from the boiler passes through the machine, leaving the condenser at low pressure (blue).

The logical development of the compound scheme was the addition of additional expansion stages to it, which increased the efficiency of work. The result was a multiple expansion scheme known as triple or even quadruple expansion machines. Such steam engines used a series of double-acting cylinders, the volume of which increased with each stage. Sometimes, instead of increasing the volume of low pressure cylinders, an increase in their number was used, just as on some compound machines.

The image on the right shows a triple expansion steam engine in operation. Steam flows through the machine from left to right. The valve block of each cylinder is located to the left of the corresponding cylinder.

The appearance of this type of steam engines became especially relevant for the fleet, since the size and weight requirements for ship engines were not very strict, and most importantly, this scheme made it easy to use a condenser that returns the exhaust steam in the form of fresh water back to the boiler (use salty sea water to power the boilers was not possible). Ground-based steam engines usually did not experience problems with water supply and therefore could emit exhaust steam into the atmosphere. Therefore, such a scheme was less relevant for them, especially considering its complexity, size and weight. The dominance of multiple expansion steam engines ended only with the advent and widespread use of steam turbines. However, modern steam turbines use the same principle of dividing the flow into high, medium and low pressure cylinders.

Direct-flow steam engines

Once-through steam engines arose as a result of an attempt to overcome one drawback inherent in steam engines with traditional steam distribution. The fact is that the steam in an ordinary steam engine constantly changes its direction of movement, since the same window on each side of the cylinder is used for both inlet and outlet of steam. When the exhaust steam leaves the cylinder, it cools its walls and steam distribution channels. Fresh steam, accordingly, spends a certain part of the energy on heating them, which leads to a drop in efficiency. Once-through steam engines have an additional port, which is opened by a piston at the end of each phase, and through which the steam leaves the cylinder. This improves the efficiency of the machine as the steam moves in one direction and the temperature gradient of the cylinder walls remains more or less constant. Once-through machines with a single expansion show about the same efficiency as compound machines with conventional steam distribution. In addition, they can work for more high revs, and therefore, before the advent of steam turbines, they were often used to drive electric generators that required high rotational speeds.

Once-through steam engines are either single or double acting.

Steam turbines

A steam turbine is a series of rotating disks fixed on a single axis, called the turbine rotor, and a series of fixed disks alternating with them, fixed on a base, called the stator. Rotor disks have blades on outside, steam is supplied to these blades and turns the disks. The stator discs have similar blades set at opposite angles, which serve to redirect the steam flow to the following rotor discs. Each rotor disc and its corresponding stator disc is called a turbine stage. The number and size of the stages of each turbine are selected in such a way as to maximize the useful energy of the steam of the speed and pressure that is supplied to it. The exhaust steam leaving the turbine enters the condenser. Turbines rotate with very high speed, and therefore, when transferring rotation to other equipment, special step-down transmissions are usually used. In addition, turbines cannot change their direction of rotation, and often require additional reverse mechanisms (sometimes additional reverse rotation stages are used).

Turbines convert steam energy directly into rotation and do not require additional mechanisms for converting reciprocating motion into rotation. In addition, turbines are more compact than reciprocating machines and have a constant force on the output shaft. Since turbines are of a simpler design, they tend to require less maintenance.

Other types of steam engines

Application

Steam engines can be classified according to their application as follows:

Stationary machines

steam hammer

Steam engine in an old sugar factory, Cuba

Stationary steam engines can be divided into two types according to the mode of use:

• Variable duty machines, which include rolling mill machines, steam winches and similar devices, which must stop and change direction frequently.
• Power machines that rarely stop and do not have to change direction of rotation. They include power engines in power plants as well as industrial engines used in factories, factories and cable railways before the widespread use of electric traction. Low power engines are used in marine models and in special devices.

The steam winch is essentially a stationary engine, but mounted on a base frame so that it can be moved around. It can be secured by a cable to the anchor and moved by its own thrust to a new location.

Transport vehicles

Steam engines were used to power various types of vehicles, among them:

• Land vehicles:
  • steam car
  • steam tractor
  • Steam excavator, and even
• Steam plane.

In Russia, the first operating steam locomotive was built by E. A. and M. E. Cherepanov at the Nizhny Tagil plant in 1834 to transport ore. He developed a speed of 13 miles per hour and carried more than 200 pounds (3.2 tons) of cargo. The length of the first railway was 850 m.

Advantages of steam engines

The main advantage of steam engines is that they can use almost any heat source to convert it into mechanical work. This distinguishes them from internal combustion engines, each type of which requires the use of a specific type of fuel. This advantage is most noticeable when using nuclear energy, since a nuclear reactor is not able to generate mechanical energy, but only produces heat, which is used to generate steam that drives steam engines (usually steam turbines). In addition, there are other sources of heat that cannot be used in internal combustion engines, such as solar energy. An interesting direction is the use of the energy of the temperature difference of the World Ocean at different depths.

Other types of external combustion engines also have similar properties, such as the Stirling engine, which can provide very high efficiency, but are significantly larger and heavier than modern types of steam engines.

Steam locomotives perform well at high altitudes, since their efficiency does not drop due to low atmospheric pressure. Steam locomotives are still in use in the mountainous areas of Latin America, despite the fact that in the lowlands they have long been replaced by more modern types of locomotives.

In Switzerland (Brienz Rothhorn) and Austria (Schafberg Bahn), new steam locomotives using dry steam have proved their worth. This type of steam locomotive was developed on the basis of Swiss Locomotive and Machine Works (SLM) models, with many modern improvements such as the use of roller bearings, modern thermal insulation, burning light oil fractions as fuel, improved steam pipelines, etc. . As a result, these locomotives have 60% lower fuel consumption and significantly lower maintenance requirements. The economic qualities of such locomotives are comparable to modern diesel and electric locomotives.

In addition, steam locomotives are significantly lighter than diesel and electric locomotives, which is especially true for mining. railways. A feature of steam engines is that they do not need a transmission, transferring power directly to the wheels.

Efficiency

Efficiency factor (COP) heat engine can be defined as the ratio of useful mechanical work to the expended amount of heat contained in the fuel. The rest of the energy is released into the environment in the form of heat. thermal efficiency machine is equal to

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The invention of steam engines was a turning point in human history. Somewhere at the turn of the 17th-18th centuries, inefficient manual labor, water wheels, and completely new and unique mechanisms began to be replaced - steam engines. It was thanks to them that the technical and industrial revolutions, and indeed the entire progress of mankind, became possible.

But who invented the steam engine? To whom does humanity owe this? And when was it? We will try to find answers to all these questions.

Even before our era

The history of the creation of a steam engine begins in the first centuries BC. Hero of Alexandria described a mechanism that only started working when it was exposed to steam. The device was a ball on which nozzles were fixed. Steam came out tangentially from the nozzles, thereby causing the engine to rotate. It was the first device that worked on steam.

The creator of the steam engine (or rather, the turbine) is Tagi al-Dinome (Arab philosopher, engineer and astronomer). His invention became widely known in Egypt in the 16th century. The mechanism was arranged as follows: streams of steam were directed directly to the mechanism with blades, and when the smoke fell, the blades rotated. Something similar was proposed in 1629 by the Italian engineer Giovanni Branca. The main disadvantage of all these inventions was too much steam consumption, which in turn required a huge amount of energy and was not advisable. Development was suspended, as the then scientific and technical knowledge of mankind was not enough. In addition, the need for such inventions was completely absent.

Developments

Until the 17th century, the creation of a steam engine was impossible. But as soon as the bar for the level of human development soared, the first copies and inventions immediately appeared. Although no one took them seriously at that time. So, for example, in 1663, an English scientist published in the press a draft of his invention, which he installed in Raglan Castle. His device served to raise water on the walls of the towers. However, like everything new and unknown, this project was accepted with doubt, and there were no sponsors for its further development.

The history of the creation of a steam engine begins with the invention of a steam engine. In 1681, a scientist from France invented a device that pumped water out of mines. At first, gunpowder was used as a driving force, and then it was replaced with water vapor. This is how the steam engine was born. A huge contribution to its improvement was made by scientists from England, Thomas Newcomen and Thomas Severen. The Russian self-taught inventor Ivan Polzunov also provided invaluable assistance.

Papin's failed attempt

The steam-atmospheric machine, far from perfect at that time, attracted Special attention in the shipbuilding industry. D. Papin spent his last savings on the purchase of a small vessel, on which he began to install a water-lifting steam-atmospheric machine of his own production. The mechanism of action was that, falling from a height, the water began to rotate the wheels.

The inventor conducted his tests in 1707 on the Fulda River. Many people gathered to look at a miracle: a ship moving along the river without sails and oars. However, during the tests, a disaster occurred: the engine exploded and several people died. The authorities got angry at the unfortunate inventor and banned him from any work and projects. The ship was confiscated and destroyed, and Papen himself died a few years later.

Mistake

The Papin steamer had the following principle of operation. At the bottom of the cylinder it was necessary to pour a small amount of water. A brazier was located under the cylinder itself, which served to heat the liquid. When the water began to boil, the resulting steam, expanding, raised the piston. Air was expelled from the space above the piston through a specially equipped valve. After the water boiled and steam began to fall, it was necessary to remove the brazier, close the valve to remove air, and cool the walls of the cylinder with cool water. Thanks to such actions, the steam in the cylinder condensed, a vacuum formed under the piston, and due to the force of atmospheric pressure, the piston returned to its original place again. During its downward movement, useful work was done. However, the efficiency of Papen's steam engine was negative. The steamer's engine was extremely uneconomical. And most importantly, it was too complicated and inconvenient to use. Therefore, Papen's invention had no future from the very beginning.

Followers

However, the history of the creation of the steam engine did not end there. The next, already much more successful than Papen, was the English scientist Thomas Newcomen. He studied the works of his predecessors for a long time, focusing on weak spots. And taking the best of their work, he created his own apparatus in 1712. The new steam engine (photo shown) was designed as follows: a cylinder was used, which was in a vertical position, as well as a piston. This Newcomen took from the works of Papin. However, steam was already formed in another boiler. Whole skin was fixed around the piston, which significantly increased the tightness inside the steam cylinder. This machine was also para-atmospheric (water rose from the mine with the help of atmospheric pressure). The main disadvantages of the invention were its bulkiness and inefficiency: the machine "ate" a huge amount of coal. However, it brought much more benefits than the invention of Papen. Therefore, it has been used in dungeons and mines for almost fifty years. It was used to pump out groundwater, as well as to dry ships. tried to convert his car so that it was possible to use it for traffic. However, all his attempts were unsuccessful.

The next scientist who declared himself was D. Hull from England. In 1736, he presented his invention to the world: a steam-atmospheric machine, which had paddle wheels as a mover. His development was more successful than that of Papin. Immediately, several such vessels were released. They were mainly used to tow barges, ships and other vessels. However, the reliability of the steam-atmospheric machine did not inspire confidence, and the ships were equipped with sails as the main mover.

And although Hull was more fortunate than Papen, his inventions gradually lost their relevance and were abandoned. Still, the steam-atmospheric machines of that time had many specific shortcomings.

The history of the creation of a steam engine in Russia

The next breakthrough happened in the Russian Empire. In 1766, the first steam engine was created at a metallurgical plant in Barnaul, which supplied air to the melting furnaces using special blower bellows. Its creator was Ivan Ivanovich Polzunov, who was even given an officer rank for services to his homeland. The inventor presented his superiors with drawings and plans for a "fiery machine" capable of powering bellows.

However, fate played a cruel joke with Polzunov: seven years after his project was accepted and the car was assembled, he fell ill and died of consumption - just a week before the tests of his engine began. However, his instructions were enough to start the engine.

So, on August 7, 1766, Polzunov's steam engine was launched and put under load. However, in November of the same year, it broke down. The reason turned out to be too thin walls of the boiler, not intended for loading. Moreover, the inventor wrote in his instructions that this boiler can only be used during testing. The manufacture of a new boiler would easily pay off, because the efficiency of Polzunov's steam engine was positive. For 1023 hours of work, more than 14 pounds of silver was smelted with its help!

But despite this, no one began to repair the mechanism. Polzunov's steam engine was gathering dust for more than 15 years in a warehouse, while the world of industry did not stand still and developed. And then it was completely dismantled for parts. Apparently, at that moment Russia had not yet grown up to steam engines.

The demands of the time

Meanwhile, life did not stand still. And humanity constantly thought about creating a mechanism that would allow not to depend on the capricious nature, but to control fate itself. Everyone wanted to abandon the sail as soon as possible. Therefore, the question of creating a steam mechanism was constantly hanging in the air. In 1753, a competition among craftsmen, scientists and inventors was put forward in Paris. The Academy of Sciences announced an award to those who can create a mechanism that can replace the power of the wind. But despite the fact that such minds as L. Euler, D. Bernoulli, Canton de Lacroix and others participated in the competition, no one made a sensible proposal.

The years went by. And the industrial revolution covered more and more countries. Superiority and leadership among other powers invariably went to England. By the end of the eighteenth century, it was Great Britain that became the creator of large-scale industry, thanks to which it won the title of world monopoly in this industry. Question about mechanical engine every day became more and more relevant. And such an engine was created.

The first steam engine in the world

The year 1784 was for England and for the whole world a turning point in the industrial revolution. And the person responsible for this was the English mechanic James Watt. The steam engine he created was the biggest discovery of the century.

For several years he studied the drawings, structure and principles of operation of steam-atmospheric machines. And on the basis of all this, he concluded that for the efficiency of the engine, it is necessary to equalize the temperatures of the water in the cylinder and the steam that enters the mechanism. The main disadvantage of steam-atmospheric machines was the constant need to cool the cylinder with water. It was costly and inconvenient.

The new steam engine was designed differently. So, the cylinder was enclosed in a special steam jacket. Thus Watt achieved his constant heated state. The inventor created a special vessel immersed in cold water (condenser). A cylinder was attached to it with a pipe. When the steam was exhausted in the cylinder, it entered the condenser through a pipe and turned back into water there. Working on the improvement of his machine, Watt created a vacuum in the condenser. Thus, all the steam coming from the cylinder condensed in it. Thanks to this innovation, the steam expansion process was greatly increased, which in turn made it possible to extract much more energy from the same amount of steam. It was the pinnacle of success.

The creator of the steam engine also changed the principle of air supply. Now the steam first fell under the piston, thereby raising it, and then collected above the piston, lowering it. Thus, both strokes of the piston in the mechanism became working, which was not even possible before. And the consumption of coal for one horsepower was four times less than, respectively, for steam-atmospheric machines, which was what James Watt was trying to achieve. The steam engine very quickly conquered first Great Britain, and then the whole world.

"Charlotte Dundas"

After the whole world was amazed by the invention of James Watt, the widespread use of steam engines began. So, in 1802, the first ship for a couple appeared in England - the Charlotte Dundas boat. Its creator is William Symington. The boat was used as towing barges along the canal. The role of the mover on the ship was played by a paddle wheel mounted on the stern. The boat successfully passed the tests the first time: it towed two huge barges 18 miles in six hours. At the same time, the headwind greatly interfered with him. But he managed.

Nevertheless, they put it on hold, because they feared that due to the strong waves that were created under the paddle wheel, the banks of the canal would be washed out. By the way, the test of "Charlotte" was attended by a man whom the whole world today considers the creator of the first steamship.

in the world

An English shipbuilder from his youth dreamed of a ship with a steam engine. And now his dream has come true. After all, the invention of steam engines was a new impetus in shipbuilding. Together with the envoy from America, R. Livingston, who took over the material side of the issue, Fulton took up the project of a ship with a steam engine. It was a complex invention based on the idea of ​​an oar mover. Along the sides of the ship stretched in a row plates imitating a lot of oars. At the same time, the plates now and then interfered with each other and broke. Today we can easily say that the same effect could be achieved with just three or four tiles. But from the standpoint of science and technology of that time, it was unrealistic to see this. Therefore, shipbuilders had a much harder time.

In 1803, Fulton's invention was introduced to the world. The steamer moved slowly and evenly along the Seine, striking the minds and imagination of many scientists and figures in Paris. However, the Napoleonic government rejected the project, and the disgruntled shipbuilders were forced to seek their fortune in America.

And in August 1807, the world's first steamer called the Claremont, in which the most powerful steam engine was involved (photo is presented), went along the Hudson Bay. Many then simply did not believe in success.

The Claremont went on its maiden voyage without cargo and without passengers. No one wanted to travel aboard a fire-breathing ship. But already on the way back, the first passenger appeared - a local farmer who paid six dollars for a ticket. He became the first passenger in the history of the shipping company. Fulton was so moved that he gave the daredevil a lifetime free ride on all of his inventions.