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Glossary of Pneumatic Terms
Accumulator. A container in which fluid is stored under pressure as a source of fluid power. Accumulator, Hydropneumatic Bladder. A hydro pneumatic accumulator in which the liquid and gas are separated by an elastic bag or bladder. Acetal Plastic. Tough, stable engineering thermoplastic with a high modulus of elasticity, high strength, good rigidity, dimensional stability, resistance to moisture, solvents and other chemicals. Active Device. A device that has an input(s) that controls a power supply to the device. Actuator. A device in which power is transferred from one pressurized medium to another without intensification. Additive. A chemical added to fluid to impart new properties or to enhance those that already exist. Air Motor. A device that converts pneumatic fluid power into mechanical torque and motion. It usually provides rotary mechanical motion. Air, Compressed (pressure). Air at any pressure greater than atmosphere. Air, Dried. Air with moisture content lower than the maximum allowed for a given application. Air, Free. Air at ambient temperature, pressure, relative humidity and density. Air, Saturated. Air at 100% relative humidity with a dew point equal to temperature. Air, Standard. Air at a temperature of 68.8° F, a pressure of 14.7 pounds per square inch absolute, and a relative humidity of 36% (0.0750 pounds per cubic foot). In gas industries the temperature of “standard air” is usually given as 60.8° F. Air. A gas mixture consisting of nitrogen, oxygen, argon, carbon dioxide, hydrogen and small quantities of neon, helium and other gases. Air Bleeder. A device for the removal of air.
Air Breather. A device permitting air movement between atmosphere and the component in which it is installed Air Motor. A device which converts pneumatic power into mechanical force and motion which usually provides rotary mechanical motion. Amplification. The ration between the output signal variations and the control signal variations (for analog devices only). Amplification, Power. The ratio between the output power variation and the corresponding input (control) power variation (for analog devices only). Amplification, Pressure. Ratio between the outlet pressure and the inlet (control) pressure. Avogadro's Law. A gas law that states that, under the same condition of temperature and pressure, equal volumes of all gases contain the same number of molecules. B
Bernoulli’s Law. If no work is done on or by a flowing frictionless liquid, its energy due to pressure and velocity, remains constant at all points along the streamline. Boyle’s Law. The absolute pressure of a fixed mass of gas varies inversely as the volume, provided the temperature remains constant. Breakout. Force necessary to inaugurate sliding. Expressed in same terms as friction. An excessive breakout valve indicates the development of adhesion. Breathing Capacity. A measure of flow rate through an air breather. Bulk Modulus. The measure of resistance to compressibility of a fluid. It is the reciprocal of compressibility. C
Cavitation. A localized gaseous condition within a liquid stream that occurs where the pressure is reduced to the vapor pressure. Charles’ Law. The volume of a fixed mass of gas varies directly with absolute temperature, provided the pressure remains constant. Circuit, Metered-In. A speed control circuit in which the control is achieved by regulating the supply flow to the actuator. Circuit, Metered-Out. A speed control circuit in which the control is achieved by regulating the exhaust flow from the actuator. Circuit, Sequence. A circuit that established the order in which two or more phases of a circuit occur. Compression Set. The amount by which a rubber specimen fails to return to original shape after release of the compressive load. Compressibility. The change in volume of a unit volume of a fluid when subjected to a unit change in pressure. Compressor. A device that...