Vacuum at the service of transport: from pneumatic tubes to Hyperloop

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Vacuum at the service of transport: from pneumatic tubes to Hyperloop
Vacuum at the service of transport: from pneumatic tubes to Hyperloop
Anonim

The Hyperloop project, the vacuum train of our time, threatens to overturn public transport. SpaceX chief Elon Musk says it will be "the fifth mode of transport." However, how did it all start? Pneumatic mail, pneumatic railway and other representatives of the "vacuum" family of the past.

Hyperloop

This type of transport has many names and varieties - pneumatic transport, pneumatic railway, vacuum train … However, all this variety, upon closer examination, unites the same principle - the creation of traction or the required speed is provided here through manipulation of air pressure.

Basically, thrust is achieved by creating a difference between the pressure in the air, with the formation of compressed or rarefied air, or a partial or complete vacuum.

Almost always, in this transport, a pipe is used, in which all the necessary transformations of the environment are performed. And the main differences between the types of "vacuum transport" are in how the traction is carried out and where the vessel (capsule, carriage) with the load is located - inside the pipe or outside it.

Let us turn to the past and see where the history of the "fifth mode of transport" began.

Fathers of pneumatics

According to some reports, the foundations of pneumatic transport were laid back in the first century AD by the Greek engineer Heron of Alexandria in his treatise "Pneumatics".

Pneumatic mail - the movement of piece or bulk objects in a light capsule using rarefied air or a partial vacuum generated in a closed (often underground) pipe, was invented by the English engineer William Murdoch in the first half of the 19th century.

However, pneumatic mail became widespread only by the beginning of the 20th century, and is still used by some institutions, such as banks (Sberbank) and some retail chains (IKEA, Media Markt).

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The idea of ​​the practical movement of not only cargo, but also people by creating artificial inhomogeneities in air pressure appeared in 1812, when the English inventor George Madhurst shared it with the scientific community.

In particular, he proposed two possible versions of a new mode of transport: either the capsule itself had to become a piston, which is acted upon by air pressure in an iron pipe, or it had to be connected to a small piston, which is inserted into the pipe and under the influence of compressed or sparse moves the wagon.

The first option, with some assumptions, can be called the predecessor of the vacuum train concepts and even the Hyperloop itself, but the second turned out to be more feasible for the technologies of the first half of the 19th century.

However, during Madhurst's lifetime, none of them was implemented.

Piston test

Although miniature models of the pneumatic railroad were created in the mid-1830s, inventors Jacob Samouda and Samuel Clegg were the first to practically implement this transport in life size, who launched the first ever operating line of this transport in 1840.

Engineers took inspiration from Madhurst's work and created a pneumatic railway line in west London about 800 meters long.

The idea was quite simple: an iron pipe with a hole at the top was located between the rails, and the car had a special piston that was located under the car and was placed in this hole.

Along the entire length of the pipe, the hole was closed with bearskin (for tightness), and was opened only under the piston, which was provided by special valves.

At one end of the pipe was a 16 horsepower pump that pumped air out of the pipe. Thus, in the pipe itself, a difference in pressure appeared - rarefied air in front of the piston and denser air behind, which led to pressure on the piston and the movement of the entire car along the pipe.

The pump was located only at one of the ends of the pipe, and the movement of the car back was provided by the force of gravity - to the point of destination, the train was moving uphill, and therefore returned down a slope.

The maximum speed that was achieved during road tests was 48 km / h.

Pneumatic boom

The demonstration line of Samouda and Clegg lasted two years and, of course, attracted the attention of the public, scientists and even the government, which was seriously interested in the prospects of the new transport.

Other engineers decided to test their strengths, a kind of boom in the development of pneumatic transport began, which was supported by state loans. The first commercial pneumatic rail line was the Dalkey Atmospheric Railway in Ireland, covering more than 2 km between Dublin and Kingstown.

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In August 1843 it opened for public use, and by March 1844 it had reached 4.5 thousand passengers a week. The Dalkey Atmospheric Railway operated for over ten years and was closed in 1855.

Progress was observed not only in the territory of the British Empire. The most "tenacious" line turned out to be Paris-Saint-Germain in France with a length of 8.5 km, which was opened for commercial use in 1847 and closed in 1860.

Apart from the relatively successful, but still very short-term and only demonstration projects of the underground pneumatic railway in New York in the second half of the 19th century, at Paris-Saint-Germain the development and even the use of this type of transport is temporarily interrupted.

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The main reason is the low efficiency compared to other types of railway transport. For a while, they forgot about pneumatic traction.

In modern times, however, the development of technology has made it possible to implement more effective projects based on the same principle, although not so many.

In Indonesia and Brazil, the so-called "Aeromovels" are currently operating - the same pneumatic railways with carriages without drivers, only moving along ramps and with electric pumps along the entire pipe, in which a partial vacuum is created, and with electric power from the rails. Also, of course, airbikes have much more advanced valve technology than their 19th century predecessors.

The ubiquity of this eco-friendly mode of transport is probably not driven by the same comparatively low efficiency and popularity of other types of public transport.

Friction-free movement

In the early 1910s, even before it was embodied in science fiction, the idea of ​​a vacuum train - that is, a train moving through a pipe with evacuated air and not touching the walls due to magnetic levitation - was experimentally demonstrated in a Russian laboratory.

Scientist Boris Veinberg from the Tomsk Institute of Technology then developed the concept of a "magnetoplane", which became quite famous not only in Russia, but also abroad.

Despite a rather difficult time for the country, Weinberg, right in the laboratory, built a working model of a vacuum train on an electromagnetic suspension, and then published the work "Motion without friction", where he described the basic principles of the new mode of transport he developed.

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Similar experiments were conducted around the same time by the French-American inventor Emile Bachelet, who even presented a similar working model in London in 1914.

But then the First World War began, and the countries of Europe had no time for science.Scientists' projects were forgotten for a while, but at least Bachelet's work was then remembered, which, in subsequent experiments, led in the 1960s to the creation of maglev - trains driven by the force of an electromagnetic field.

The concept of vacuum trains, on the other hand, moved to science fiction, and for a long time served mainly as the subject of reasoning and dreams of writers and futurists. They tried to implement something similar in Switzerland, but the project was closed after doubts about its commercial viability.

This was the case until the early 2010s.

Fifth mode of transport

In 2010, Chinese scientists announced that by 2020 they intend to build the first vacuum train capable of speeds up to 1000 km / h. Since then, however, nothing has been heard about the project.

And in 2012, Elon Musk - the founder of SpaceX, Tesla Motors and SolarCity - announced that he was ready to give the world the concept of the fifth mode of transport (after water, air, road and rail) - Hyperloop.

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The project, however, does not entirely follow the concept of a vacuum train - in Hyperloop, for example, magnetic levitation is not used at all - but it is very close to it.

Musk proposed to build between San Francisco and Los Angeles (550 km) an underground or ground pipe with a diameter of approximately 2.2 meters, in which, in a partial vacuum (pressure - 1/1000 atmospheric), capsules of dense aluminum would transport people at speeds of the order of 1000 km / h - which would be achieved, of course, with practically no friction of the medium.

The part of the air that should be in the pipe would be sucked in by the pump on the nose of the capsule and transferred under the train's "skis" - thus, the capsule would not touch the walls of the pipe, levitating above its surface.

The movement and braking of the train itself would be carried out by linear electric motors installed on it.

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According to Musk, such a train is capable of transporting passengers along the specified intercity distance in less than half an hour, moreover, at a fairly low price per ticket.

One of the projects of the vacuum train is also the UK-USA transatlantic underwater train based on magnetic levitation, although the project is still at the very early concept stage

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When transferred to Russian geography, this suggests that Hyperloop would take passengers from Moscow to St. Petersburg in about 40 minutes, which, of course, would become the embodiment of the dreams of very, very many.

The environmental friendliness of transport and the absence of traffic jams add to the advantages. Overloads on the body of passengers are also minimized and, according to calculations, will be 0.5 g.

However, computer simulations have shown that with all the declared characteristics, the Hyperloop concept should be significantly improved. The cost of the project, named by Musk at $ 6 billion, according to many experts, is significantly underestimated, because we are talking about a truly new type of transport.

Various political and economic obstacles are also still standing in the way of Musk, and the project has been postponed indefinitely at the moment. However, Musk is still going to build a demo model (just like Samouda and Clegg) to prove the feasibility and effectiveness of Hyperloop.

In the cartoon "Futurama", giant pneumatic pipes, through which people independently, but deliberately ridiculously move through the megalopolis of the model of the 3000th year, serve as a mockery of naive extrapolations of modern trends regarding future technologies.

Probably, contemporaries of Madhurst and Samouda could seriously write something similar, but none of them suspected that the pneumatic railway would be on the sidelines of scientific and technological progress just 20 years after its bright debut in London.

Maybe a similar fate awaits the Chinese vacuum train and the American Hyperloop. However, in times when technological progress is moving faster than ever before and continues to accelerate, anything is possible.

How will the face of global public transport change if the Hyperloop demonstration model is successful? Guessing, as the experience of the past shows, is not worth it.

However, it is hardly harmful to dream of a 40-minute journey from St. Petersburg to Moscow, standing in a traffic jam for many hours.

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