Menu
As early as 200 BC, humans began to utilize water power through water wheels. Until 1776, when Watt made the steam engine practical, the power used by humans, apart from human power, animal power, and wind power, was water power. However, that was utilizing the potential energy of water, which does not count as hydraulics in the classic sense.
Around 1600, the astronomer Mr. Johannes Kepler, who proposed Kepler’s three laws and laid the foundation for Newton’s law of universal gravitation, invented the gear pump, but it was not put to practical use at that time. In 1653, the Frenchman Pascal proposed the famous Pascal’s law, which laid the theoretical foundation for hydraulic presses. In 1795, the Englishman J. Bramah built the first industrial (manual) hydraulic press, beginning truly classic hydraulic technology.
The world’s first industrial hydraulic press a) Model displayed at Kelham Island Museum in Sheffield, England b) Attached drawing from patent application document c) Schematic diagram of hydraulic system 1—Handle 2—Plunger 3—Hydraulic pump 4—Pipeline 5—Oil discharge check valve 6—Hydraulic cylinder 7—Piston 8—Workpiece 9—Oil suction check valve 10—Pipeline 11—Unloading switch valve 12—Return oil pipe 13—Oil tank
In the early 19th century, after the steam engine became practical, both England and France began to construct 5.5MPa high-pressure water networks to provide energy for driving hydraulic machinery. In the second half of the 19th century, the Englishman Armstrong developed many hydraulic components, mainly used for ship hydraulic anchor winches and hydraulic elevators. All hydraulic systems require hydraulic valves, so the history of hydraulic technology development is also the development history of hydraulic valves. The principles of many hydraulic valves currently in use were already proposed and practically applied at that time.
In 1880, Austria used hydraulic drilling machines when excavating Alpine tunnels, which can be considered the originator of mobile hydraulics.
In 1893, the world’s first open-die forging hydraulic press was built at the Bethlehem Steel Company in the United States.
In 1903, Americans Harvey Williams and Reynold Janney (Waterbury Tool Company) developed the earliest swash plate piston pumps and motors.
In 1905, people discovered that mineral oil, due to its high viscosity, less leakage, and better lubrication performance, was more suitable for hydraulics than water. Therefore, mineral oil was quickly and universally adopted. At that time, the term “Oilhydraulics” (oil pressure) was specifically invented to emphasize the difference from “water pressure,” and it has been used ever since. By 1940, hydraulic pumps with working pressures up to 35MPa were already in mass production. So it can be completely said that the adoption of mineral oil created modern hydraulic technology.
Hydraulic technology was advanced more rapidly during the two World Wars. Bosch Rexroth of Germany, currently among the world’s leading hydraulic industry companies, was formerly an iron foundry and began manufacturing hydraulic pumps in 1952. For various considerations, water pressure was not immediately completely replaced and continued to be used in some fields. Germany built a 30,000t die forging hydraulic press in 1944. London’s high-pressure water network reached 300km by 1939, providing 7.5 million m³ of pressurized water annually to 8,000 hydraulic devices. This network was still providing hydraulic power for London Underground elevators until the 1970s.
During this period, as electric motors and internal combustion engines became increasingly practical, steam engines driving hydraulic pumps were gradually replaced. Liquid supply changed from centralized to distributed, and liquid transmission pipelines changed from long pipes to short pipes. Working pressure gradually increased, while working flow relatively decreased. In 1968, Professor W. Backé of RWTH Aachen University in Germany was the first to separate hydraulics and pneumatics from mechanical engineering as an independent specialty, establishing the world’s first hydraulic and pneumatic research institute IHP (predecessor of IFAS), which trained a large number of hydraulic professionals who combined theory with practice, playing a tremendous role in advancing hydraulic technology.
The electrically proportional control valve invented in the 1970s greatly expanded the application of hydraulic electrical control, and the cover plate two-way cartridge valve invented in the same period significantly reduced the manufacturing cost of large-flow hydraulic systems. These innovations decisively promoted the hydraulic industry. In the 1990s, due to the invention of practical ceramic processing technology, manufactured ceramic parts had lower lubrication requirements, therefore, clean water hydraulics regained favor. However, until now, the working pressure of clean water hydraulics can generally only be below 16MPa, therefore, it is only used in some industries and locations with special requirements, such as food, beverages, cosmetics, grain processing, pharmaceuticals, medical care, papermaking, culture and entertainment, sports, offices, household robots, etc., each eating their own rice, clean water hydraulics and oil pressure do not form competition.
Reviewing the development history of hydraulics, it can be seen that hydraulics, starting from 1795, had a good relationship with water for more than a hundred years, and had thousands upon thousands of children. But in 1905, it met oil, a sticky fellow, and immediately got along well with it, not caring even though the price was tens of thousands of times higher. After seventy or eighty years of this, it began to dislike oil again, complaining about this shortcoming and that defect, and started missing the old lover. Therefore, this fellow hydraulic technology, if not “fickle,” can definitely be considered something that “changes affections when seeing something new”! However, this seemingly “changing affections when seeing something new” is actually a process of continuous improvement, seeking what is better and more suitable for application. From this it can be seen that for hydraulic technology, there is only better, no best!
China’s currently commonly used term “water hydraulics” includes high water-based liquids, that is, water containing components that increase viscosity. Although it shares commonalities with clean water hydraulics, there are also many differences, such as: availability, hygiene, applicable occasions, requirements for components, etc. Therefore, these two concepts should not be confused.
Currently, the pressure (working) media used in hydraulic systems, for various factors such as safety and environmental protection, are increasingly using other liquids, such as fire-resistant (fire-retardant, flame-resistant) hydraulic oils, oil-in-water, water-in-oil suspensions, biodegradable synthetic esters, vegetable oils, etc., but mainly still based on mineral oil. According to Shell Oil Company’s 2016 statistics, it accounts for approximately 88%, and in 2016, the world consumed approximately 3.8 billion liters of hydraulic oil, valued at approximately 4.5 billion US dollars.
“A leader in hydraulic technology, A convenient choice around you”
