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Air Pump - Artificial Vacuum Can Be Achieved |
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When air pump is used to compress the air of a closed vessel it is called Force pump and when it is used to exhaust the air from a closed vessel, it is called Exhaust pump. Air pumps also consists a cylinder fitted with a piston and two valves. The best example of compressing air is ordinary bicycle pump. In this the piston is provided with more or less flexible leather collar which allows the air to pass down it as soon as the piston is lifted. But during the down stroke of the piston this leather part does not allow the air to pass out,hence it acts as both piston and valve.
The second valve,at the bottom of piston prevents the air from getting back into the cylinder from the tire during the upstroke of the piston. The Principle of the Vacuum pump is same as the Force pump,but the direction of the valves open are reversed.
The first artificial vacuum was produced by Otto von Guericke,by using an ordinary pump which is used in wells. Instead of pumping out the air out of an open vessel,he pumped out the air from closed vessel.
Ordinary vacuum can be achieved by a piston working in a brass cylinder but if it need to achieve high vacuum such as in incandescent lamp or in Lamp X-ray bulbs a very perfect instrument is required.
The Modern air pump is capable of achieving a pressure of 100,000,000 atmosphere.
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