Air Pressure - Revision history

DT Online: Added category link

2015-06-07T17:45:03Z

Added category link

← Older revision		Revision as of 17:45, 7 June 2015
Line 26:		Line 26:

	[[Category:Secondary]]		[[Category:Secondary]]
			[[Category:Pneumatics]]

DT Online at 08:25, 26 April 2015

2015-04-26T08:25:44Z

← Older revision		Revision as of 08:25, 26 April 2015
Line 25:		Line 25:


	{{Secondary ~~Pneumatics}}~~		[[Category:Secondary]]

DT Online: Added Template

2014-11-22T17:14:24Z

Added Template

← Older revision		Revision as of 17:14, 22 November 2014
Line 23:		Line 23:

	In practice, losses due to friction, escaping air, etc., mean that the full amount of force calculated will not be available at the output of the piston, or '''''outstroke''''' and on the '''''instroke''''' of a double-acting cylinder, the surface area is reduced because of the piston rod. This means that the compressed air does not have as big an area to push against and so it does not produce as big a force. The resulting surface area, or '''''effective area''''' is found subtracting the area of the piston rod from the surface area of the piston - i.e. ''Effective area = piston area – piston rod area''		In practice, losses due to friction, escaping air, etc., mean that the full amount of force calculated will not be available at the output of the piston, or '''''outstroke''''' and on the '''''instroke''''' of a double-acting cylinder, the surface area is reduced because of the piston rod. This means that the compressed air does not have as big an area to push against and so it does not produce as big a force. The resulting surface area, or '''''effective area''''' is found subtracting the area of the piston rod from the surface area of the piston - i.e. ''Effective area = piston area – piston rod area''


			{{Secondary Pneumatics}}

DT Online: Spelling correction

2014-11-22T15:33:46Z

Spelling correction

← Older revision		Revision as of 15:33, 22 November 2014
Line 22:		Line 22:
	:::::::Force = Pressure x 3.14 x Diameter<sup>2</sup> ÷ 4		:::::::Force = Pressure x 3.14 x Diameter<sup>2</sup> ÷ 4

	In practice, losses due to friction, escaping air, etc., mean that the full amount of force calculated will not be available at the output of the piston, or '''''outstroke''''' and on the '''''instroke''''' of a double-acting cylinder, the surface area is reduced because of the piston rod. This means that the compressed air does not have as big an area to push against and so it does not produce as big a force. The resulting surface area, or '''''effective area''''' is found ~~subtacting~~ the area of the piston rod from the surface area of the piston - i.e. ''Effective area = piston area – piston rod area''		In practice, losses due to friction, escaping air, etc., mean that the full amount of force calculated will not be available at the output of the piston, or '''''outstroke''''' and on the '''''instroke''''' of a double-acting cylinder, the surface area is reduced because of the piston rod. This means that the compressed air does not have as big an area to push against and so it does not produce as big a force. The resulting surface area, or '''''effective area''''' is found subtracting the area of the piston rod from the surface area of the piston - i.e. ''Effective area = piston area – piston rod area''

DT Online: Air Pressure

2014-11-22T15:32:37Z

Air Pressure

New page

[http://en.wikipedia.org/wiki/Pressure '''Pressure'''] is measured as the Force per Unit Area. In the case of [http://en.wikipedia.org/wiki/Atmospheric_pressure '''Atmospheric Pressure'''] at sea level for example, the standard unit of measurement is '''1 [http://en.wikipedia.org/wiki/Bar_%28unit%29 Bar'''] which is equivalent to 100,000 [http://en.wikipedia.org/wiki/Newton_%28unit%29 '''Newtons'''] of force on each square metre of surface area or, in [http://en.wikipedia.org/wiki/International_System_of_Units '''SI Units'''], 1 Bar = 100KNm-2 ''(kilonewtons per square metre)''. Alternatively, 1 Bar = 100KP, since a Nm2 = a pascal ''(named after the French inventor [http://en.wikipedia.org/wiki/Blaise_Pascal '''Blaise Pascal'''])'' or, in [http://en.wikipedia.org/wiki/Imperial_units '''Imperial Units'''], 14.5 pounds per square inch ''(PSI)''.

[[File:AirPressureMeasurement.jpg|200px|right]]
Atmospheric Pressure is an '''''absolute pressure''''' measurement because a perfect vacuum is taken as the zero value

If atmospheric pressure is used as a zero-reference, the pressure measurement is called '''''gauge pressure''''' and is used for [http://en.wikipedia.org/wiki/Pressure_measurement '''pressure measurement'''] of closed systems, such as a tyre pressure or within a pneumatic system.

It follows that '''''absolute pressure''''' is equal to '''''gauge pressure''''' plus '''Atmospheric Pressure'''.

Since Pressure is measured as the Force per Unit Area (P=F÷A) then Force equals Pressure x Area.[[File:PneumaticCylinderDimensions.jpg |300px|right]] This can be used to calculate the force exerted by a pneumatic cylinder as follows:

:::::::Force = Pressure x Area
Force produced by cylinder''(N)'' = Pressure''(Nmm2)'' x Area of Piston''(mm2)''

:''But:'' Area = π x Radius2 = π x Diameter2 ÷ 4

Therefore:
:::::::Force = Pressure x 3.14 x Diameter2 ÷ 4

In practice, losses due to friction, escaping air, etc., mean that the full amount of force calculated will not be available at the output of the piston, or '''''outstroke''''' and on the '''''instroke''''' of a double-acting cylinder, the surface area is reduced because of the piston rod. This means that the compressed air does not have as big an area to push against and so it does not produce as big a force. The resulting surface area, or '''''effective area''''' is found subtacting the area of the piston rod from the surface area of the piston - i.e. ''Effective area = piston area – piston rod area''