Instruct: Given a question, retrieve relevant passages that answer the question.
Query: When were vacuums invented?
The vacuum cleaner evolved from the carpet sweeper via manual vacuum cleaners. The first manual models, using bellows, were developed in the 1860s, and the first motorized designs appeared at the turn of the 20th century, with the first decade being the boom decade.
Armstrong began working on his first major invention while still an undergraduate at Columbia. In late 1906, Lee de Forest had invented the three-element (triode) "grid Audion" vacuum-tube. How vacuum tubes worked was not understood at the time. De Forest's initial Audions did not have a high vacuum and developed a blue glow at modest plate voltages; De Forest improved the vacuum for Federal Telegraph. By 1912, how vacuum tubes worked was understood, and the advantages of high vacuum tubes were appreciated.
Goblin Vacuum Cleaners in the early 1930s were manufactured by the British Vacuum Cleaner and Engineering Co. Ltd. (BVC). The managing director was Hubert Cecil Booth who the company claimed had in fact invented the vacuum cleaner in about 1900, and which was subsequently copied in the USA and elsewhere.
The variation on the gravity pouring technique is to fill the mold using a vacuum. A common form of this is called the "Hitchiner" process after the Hitchiner Manufacturing Company that invented the technique. In this technique, the mold has a downward fill pipe that is lowered into the melt. A vacuum draws the melt into the cavity; when the important parts have solidified, the vacuum is released, and the unused material leaves the mold. The technique can use substantially less material than gravity pouring because the sprue and some gating need not solidify.
Before the transistor was invented, radios used vacuum tubes. Although portable vacuum tube radios were produced, they were typically bulky and heavy. The need for a low voltage high current source to power the filaments of the tubes and high voltage for the anode potential typically required two batteries. Vacuum tubes were also inefficient and fragile compared to transistors, and had a limited lifetime.
In 1654, Otto von Guericke invented the first vacuum pump and conducted his famous Magdeburg hemispheres experiment, showing that teams of horses could not separate two hemispheres from which the air had been partially evacuated. Robert Boyle improved Guericke's design and with the help of Robert Hooke further developed vacuum pump technology. Thereafter, research into the partial vacuum lapsed until 1850 when August Toepler invented the Toepler Pump and Heinrich Geissler invented the mercury displacement pump in 1855, achieving a partial vacuum of about 10 Pa (0.1 Torr). A number of electrical properties become observable at this vacuum level, which renewed interest in further research.
The word “Vacuum” is originated from the Latin word “vacua”, which is translated to the word “empty”.Physicist use vacuum to describe a partially empty space, where air or some other gases are being removed from one container. The idea of vacuum relating to the empty space has been speculated as early as 5th century from Greek philosophers, Aristotle (384-322 B.C.) was the one who came up with the relation of vacuum being an empty space in nature would be impossible to ever create. This idea had stuck around for over centuries until the 17th century, when vacuum technology and physics was discovered. In the mid 17th century, Evangelista Torricelli studied the properties of a vacuum generated by a mercury column in a glass tube; this became the barometer, an instrument to observe variations in atmospheric air pressure. Otto von Guericke spectacularly demonstrated the effect of atmospheric pressure in 1654, when teams of horses could not separate two 20-inch diameter hemispheres, which had been placed together and evacuated. In 1698, Thomas Savery patented a steam pump that relied on condensation of steam to produce a low-grade vacuum, for pumping water out of mines. The apparatus was improved in the Newcomen atmospheric engine of 1712; while inefficient, it allowed coal mines to be exploited that otherwise would flood by ground water. During the years of 1564-1642, the famous scientist Galileo was one of the first physicist to conduct experiments to develop measured forces to develop vacuum using a piston in a cylinder.This was a big discovery for scientist and was shared among others. French scientist and philosopher Blaise Pascal used the idea that was discovered to look into further research of vacuum. Pascal discoveries were similar to Torricelli’s research as Pascal used similar methods to pull vacuum using mercury. It was until the year 1661, when the mayor of the city of Magdeburg used this discovery to invent or retrofit new ideas. The mayor Otto von Guericke created the first air pump, modified the idea of water pumps, and also modified manometers.Vacuum engineering today, provides the solution for all thin film needs in the mechanical industry. This method of engineering is typically used for R&D needs or large scale material production.
The bipolar transistor was invented in 1947. From 1955 onwards transistors replaced vacuum tubes in computer designs, giving rise to the "second generation" of computers. Compared to vacuum tubes, transistors have many advantages: they are smaller, and require less power than vacuum tubes, so give off less heat. Silicon junction transistors were much more reliable than vacuum tubes and had longer, indefinite, service life. Transistorized computers could contain tens of thousands of binary logic circuits in a relatively compact space.
The first practical device that could amplify was the triode vacuum tube, invented in 1906 by Lee De Forest, which led to the first amplifiers around 1912. Vacuum tubes were used in almost all amplifiers until the 1960s–1970s when the transistor, invented in 1947, replaced them. Today, most amplifiers use transistors, but vacuum tubes continue to be used in some applications.
Zero-point energy evolved from historical ideas about the vacuum. To Aristotle the vacuum was , "the empty"; space independent of body. He believed this concept violated basic physical principles and asserted that the elements of fire, air, earth, and water were not made of atoms, but were continuous. To the atomists the concept of emptiness had absolute character: it was the distinction between existence and nonexistence. Debate about the characteristics of the vacuum were largely confined to the realm of philosophy, it was not until much later on with the beginning of the renaissance, that Otto von Guericke invented the first vacuum pump and the first testable scientific ideas began to emerge. It was thought that a totally empty volume of space could be created by simply removing all gases. This was the first generally accepted concept of the vacuum.
A vacuum pump is a device that removes gas molecules from a sealed volume in order to leave behind a partial vacuum. The first vacuum pump was invented in 1650 by Otto von Guericke, and was preceded by the suction pump, which dates to antiquity.
All these early technologies were superseded by the vacuum tube feedback electronic oscillator, invented in 1912 by Edwin Armstrong and Alexander Meissner, which used the triode vacuum tube invented in 1906 by Lee De Forest. Vacuum tube oscillators were a far cheaper source of continuous waves, and could be easily modulated to carry sound. Due to the development of the first high-power transmitting tubes by the end of World War 1, in the 1920s tube transmitters replaced the arc converter and alternator transmitters, as well as the last of the old noisy spark transmitters.
However actual amplification by a vacuum tube only became practical with Lee De Forest's 1907 invention of the three-terminal "audion" tube, a crude form of what was to become the triode. Being essentially the first electronic amplifier, such tubes were instrumental in long-distance telephony (such as the first coast-to-coast telephone line in the US) and public address systems, and introduced a far superior and versatile technology for use in radio transmitters and receivers. The electronics revolution of the 20th century arguably began with the invention of the triode vacuum tube.
This process was invented by Henri Nestlé in 1866, of Nestlé Chocolate fame, although the Shakers were already using a vacuum pan earlier than that (see condensed milk).
European railway air brakes include the Kunze-Knorr brake (invented by Georg Knorr and manufactured by Knorr-Bremse) and the Oerlikon. The working principle is the same as for the Westinghouse air brake. In the steam era, Britain's railways were divided – some using vacuum brakes and some using air brakes – but there was a gradual standardization on the vacuum brake. Some locomotives, e.g. on the London, Brighton and South Coast Railway, were dual-fitted so that they could work with either vacuum- or air-braked trains. In the diesel era, the process was reversed and British Railways switched from vacuum-braked to air-braked rolling stock in the 1960s.
The main competitor to the air brake is the vacuum brake, which operates on negative pressure. The vacuum brake is a little simpler than the air brake, with an ejector with no moving parts on steam engines or a mechanical or electrical "exhauster" on a diesel or electric locomotive replacing the air compressor. Disconnection taps at the ends of cars are not required as the loose hoses are sucked onto a mounting block.
Another technical invention is the vacuum pump. Such invention is used to remove gas molecules from sealed volume thus leaving behind a partial vacuum. More than one vacuum pumps are used in a single application to create fluent flow. Fluent flow is used to allow a clear path made using vacuum to remove any air molecules in the way of the process. Vacuum will be used in this process to attempted to create a perfect vacuum. A type of vacuum such as partial vacuum can be caused by the usage of positive displacement type pumps. A positive displacement pump is able to transfer gas load from the entrance to the exit port, but due to its limitation of design it can only achieve a relatively low vacuum. In order to reach a higher vacuum, other techniques must be used. By using a series of pump such as following up a fast pump down with a positive displacement type pump will create a way better vacuum than using a single pump. These combination of pump used is usually determined by the need of vacuum in the system.
Other coffee brewing devices became popular throughout the nineteenth century, including various machines using the vacuum principle. The Napier Vacuum Machine, invented in 1840, was an early example of this type. While generally too complex for everyday use, vacuum devices were prized for producing a clear brew, and were popular up until the middle of the twentieth century.
A vacuum coffee maker brews coffee using two chambers where vapor pressure and vacuum produce coffee. This type of coffee maker is also known as "vac pot", "siphon" or "syphon coffee maker," and was invented by Loeff of Berlin in the 1830s. These devices have since been used for more than a century in many parts of the world. Design and composition of the vacuum coffee maker varies. The chamber material is borosilicate glass, metal, or plastic, and the filter can be either a glass rod or a screen made of metal, cloth, paper, or nylon. The Napier Vacuum Machine, presented in 1840, was an early example of this technique. While vacuum coffee makers generally were excessively complex for everyday use, they were prized for producing a clear brew, and were quite popular until the middle of the twentieth century. The Bauhaus interpretation of this device can be seen in Gerhard Marcks' Sintrax coffee maker of 1925.
Much of Wehnelt's research dealt with thermionic emission, the emission of electrons in vacuum tubes. In this context, he developed in 1902/03 the Wehnelt cylinder, an electrode used in electron guns. In 1904 he developed what is arguably his most important invention, the Wehnelt or oxide cathode for vacuum tubes. He found that when the cathode in a vacuum tube is coated with an alkaline earth metal oxide, such as calcium oxide or barium oxide, its work function is reduced, causing it to emit electrons more rapidly. The oxide cathode became the standard type of cathode used in vacuum tubes to the present day.
Prior to effective engine control unit computers, engine vacuum was used for many functions in an automobile. Vacuum switches were employed to regulate this flow. For instance a dual port vacuum switch located in a port on the intake manifold monitored the coolant temperature in the coolant crossover. It received vacuum (port E on the switch) from the carburetor. The vacuum flowed through the switch to a vacuum solenoid (such as a heat riser, used to restrict exhaust allowing the engine to heat up faster). When the coolant heated to operating temperature the vacuum switch closed off the port (port S on the vacuum switch) turning off the vacuum to the heat riser. The result is to clear the exhaust restriction. The switch monitored the temperature and when conditions were right it performed its designed function.
In 1654, Otto von Guericke invented the first vacuum pump and conducted his famous Magdeburg hemispheres experiment, showing that teams of horses could not separate two hemispheres from which the air had been evacuated. Robert Boyle improved Guericke's design and conducted experiments on the properties of vacuum. Robert Hooke also helped Boyle produce an air pump which helped to produce the vacuum. The study of vacuum then lapsed until 1855, when Heinrich Geissler invented the mercury displacement pump and achieved a record vacuum of about 10 Pa (0.1 Torr). A number of electrical properties become observable at this vacuum level, and this renewed interest in vacuum. This, in turn, led to the development of the vacuum tube.
Numatic vacuums with faces on the body/canister (Numatic Henrys did not actually say "Henry" on the cap until 1981) were invented first in 1979, 123 years after the first invention of the vacuum. In 1981, the first Numatic model to say a name on the cap (Henry) was created. The first model of Henry started as somewhat of a toy, with the functionality of a vacuum. The face appealed to children and adults alike, and was very popular for its lovable face. Henry was also one of the first vacuums to use Microfiber dust bags, which are large capacity dust bag known as HEPA-FLO bags which are made of a strong material that carry dust and other unwanted materials into the HEPA-FLO and stay in there unlike any paper bags which tend to rip and leak dust. Since the introduction of Henry in 1981, it has sold 7-8 million units, with around 20,000 more being sold each week (roughly 2857 per day). In 2017, the EU introduced a new law that gave vacuum cleaners a limit to their wattage, making 900W the maximum.. This required Numatic to change about 80% of their vacuums, because most of them were 1200W. The new law was meant to conserve power, and also bringing the average cost of vacuum cleaning per year from £11 to £7. 
Negative transconductance oscillators, such as the transitron oscillator invented by Cleto Brunetti in 1939, are similar negative resistance vacuum tube oscillator circuits which are based on negative transconductance (a fall in current through one grid electrode caused by an increase in voltage on a second grid) in a pentode or other multigrid vacuum tube. These replaced the dynatron circuit and were employed in vacuum tube electronic equipment through the 1970s.
In 1924, Gustaf Sahlin came to America to set up Electrolux Corp USA to import and sell the new tank type vacuum cleaner in America. The machine was the revolutionary Lux Model V made by AB Electro-Lux of Sweden and invented by Axel Wenner-Gren. People did not know what the new contraption was at first, but when showed how well it cleaned in their home, they were sold. In 1929, a shipment of Model XI cleaners sank, forcing Electrolux Corp. to build machines in the US. In 1931, the White Sewing Machine Company in Cleveland, OH was contracted to build the Model XII, however this was not a permanent move as Electrolux Corp. wanted its own factory. In 1933, Electrolux Corp. set up a new factory in Old Greenwich, Connecticut. With Electrolux Corp. in good shape and making its own products, AB Electrolux divested its stock to focus on refrigerator production and made itself a minority shareholder. From then on the two companies sold different products. The American products were never sold in Europe and the European products were never sold in America.
In 1937, the now American-owned Electrolux Corp. debuted the Electrolux Model XXX (Model 30). It was the first American-only Electrolux. The Model XXX was sold from 1937-1954, making it the longest made vacuum and in that time span over 14 million where sold. A Model XXX is currently on display at the Smithsonian and it is considered one of the top hundred U.S. inventions of all time. During World War II, Electrolux Corp halted vacuum production to focus on the war effort. The company made electric motors and control systems for the Army and Navy.
In 1952, the company debuted the Electrolux Model LX, the first vacuum that would know when it is full and also the first vacuum to use a self-sealing bag. That same style bag is still in use on some of the new Aerus-Lux model canister vacuums today. This machine would lay the foundation for every other North American Electrolux vacuum produced.
In 1968, AB Electrolux sold its minority shares to Consolidated Foods, which then bought enough stock to make it the majority shareholder. That same time, Consolidated Foods also acquired Electrolux Canada Ltd. from AB Electrolux. Electrolux Corp USA and Electrolux Canada Ltd where independent companies and stayed that way until the mid 1980s. From the late 1960s to the late 1990s Electrolux Corp. was a subsidiary of Consolidated Foods. In 1970, Electrolux Corp. opened up its Bristol, VA manufacturing center which eventually replaced the much older Old Greenwich factory. As of 2014 it is still the main factory.
In 1906, Lee De Forest found that a small voltage on a grid of metal wires could control a much larger current in a beam of cathode rays passing through a vacuum tube. His invention, called the triode, was the first device that could amplify electric signals, and revolutionized electrical technology, creating the new field of "electronics". Vacuum tubes made radio and television broadcasting possible, as well as radar, talking movies, audio recording, and long distance telephone service, and were the foundation of consumer electronic devices until the 1960s, when the transistor brought the era of vacuum tubes to a close.