PNEUMATIC PISTON
PNEUMATIC PISTON
History
Of
Pneumatic Piston
As with many forms of technology, the first use of a form of pneumatic technology dates back many thousands of years. In this instance, a Greek mathematician by the name of Hero of Alexandria wrote in the
first century about how he used wind to generate power and transport objects, however it wasn’t until the 1600s that German physicist Otto von Guericke first invented a vacuum pump that utilized air pressure. ​Following the work of Guericke, the 1800’s proved to be a pivotal century in the evolution of pneumatics as many more became aware of how compressed air could be used to great effect. The compound air compressor, which compresses air in a series of cylinders, was first patented in 1829. 1872 saw this form of compressor technology improved further as the cylinders were cooled by water to improve efficiency. This also resulted in the invention of water-jacketed cylinders.The first major functional development came in 1867 when an American inventor, Alfred Beach, built a pneumatic subway train in New York. He showed how passengers could be transported along a pipe through pneumatic power, with the subway running one block in 1870 to become the first of its kind in America. The late 1800’s saw John Wanamaker, an illustrious American merchant, become the first to introduce pneumatic tubes in the United States Post Office to quickly transport letters from one area of the building to another.The 1900s saw further evolution for pneumatics as components were used for the first time in jet engines in the form of centrifugal and axial-flow compressors. Further developments took place throughout the century with advancements in labor-saving devices in the form of machinery that would assist or even reduce the need for manpower as well as automatic machinery, tools and control systems.
What is it?
The term ‘pneumatic’ is based on the Greek word ‘pneumatikos’, meaning ‘coming from the wind.’ Pneumatic is defined as the use of pressurized air to do work. Pneumatic cylinder(s) (sometimes known as air cylinders) are mechanical devices, which use the power of compressed gas to produce a force in a reciprocating linear motion. Like hydraulic cylinders, something forces a piston to move in the desired direction. The piston is a disc or cylinder, and the piston rod transfers the force it develops to the object to be moved. Engineers sometimes prefer to use pneumatics because they are quieter, cleaner, and do not require large amounts of space for fluid storage.Because the operating fluid is a gas,
leakage from a pneumatic cylinder will not drip out and contaminate the surroundings, making pneumatics more desirable where cleanliness is a requirement.
How does it work?
Consider an empty container, such as container A. Even though it may look empty, it is actually full of air molecules. Air molecules are invisible, but they still possess weight and mass, and exert pressure. container A’s pressure matches the air pressure of the room it is in.
Once the container is sealed (container B) the molecules trapped inside exert pressure when squeezed or ‘compressed’ as they collide with each other and the sides of the container. It is the empty space and the elasticity of the impact between the air molecules and the container that allows for the air to be compressed. The force of the air molecules acting on a surface, such as the piston, is called pressure.
The amount of pressure the air molecules exert depends on the number of molecules and amount of collisions that occur between the molecules and the inside surface of the container. Air molecules that are compressed contain potential energy. If the hand and piston are removed (container C), the compressed air will expand until the pressure inside and outside the container are the same. Using a controlled airflow circuit, the force of expanding air can be converted into kinetic energy that can power and operate a system.
What is its present day usage ?
The pneumatics industry continues to evolve today with the leading names continuing to produce components that offer that little bit more to improve efficiency, performance and functionality. Pneumatics plays an essential role in airplanes to stabilize gauges in the event of an electrical failure. This in turn enables the pilot to still have a clear understanding of and control over the important figures that will help him land the plane safely. Modern pneumatic cylinders offer fast, accurate power for low-pressure applications, giving a variety of industries, from packaging to amusement park rides and medical devices to automation control, simple, safe and powerful controls.
PATENT
SKETCHES
