GENERAL CATALOGUE API

Introduction General technical information

Physical magnitudes and data The pneumatic components use compressed air. Pressure is a force that is applied per unit of area. The pressure can be measured with an instrument - the manometer - is called manometric or relative to the atmospheric pressure in which the instrument is placed. Absolute pressure is obtained by adding atmospheric pressure to the manometric pressure. Units of measurement - International System (SI) The SI units were introduced in the majority of Countries on the basis of international conventions. The aim is to achieve sole units of measurement in order to avoid the difficult conversions from one system of measurement to another. The SI system consider seven fundamental physical magnitudes with their respective units of measurement. All the other units are derived from these. The fundamental units are: length in meters [ m ], mass in kilograms [ Kg ], time in seconds [ s ], electrical current in amperes [ A ], temperature in degrees Kelvin [ °K ], molecular quantity in moles [ mol ], luminous intensity in candelas [ cd ]. Forces are derived magnitudes and are expressed in Newtons [ N ]. According to the fundamental law of dynamics, one Newton is the force required to accelerate a mass of 1 Kg to 1 m/s 2 . As 1 Kp is the force required to give a mass of 1 Kg the acceleration of gravity, which is equivalent to 9.81 m/ s 2 , it follows that 1 Kp = 9.81 N = 10 N (approximately). Indeed, the latter value is assumed in order to avoid an excessive precision of calculation. Pressure is thus measured in N/m2, a unit known as the Pascal [ Pa ]. The unit of measurement that is equivalent to 100x103 Pa [ bar ] is still accepted. We can write 1 bar = 100 KPa.

SI units

Magnitude

Symbol of formula

SI units

Accepted measurement units

Conversion factors

Name

Unit

Multiple Name

Unit

km cm mm 2 mm 2 3 mm 3 cm cm

Lenght

I

Meter

m

-

-

-

Are Hectare

a ha

1 a = 102 m 2 1 ha = 104 m 2 (used only for land)

Area

A

Square meter

m 2

Volume

V

Cubic meter

m 3

Litre

l

1 l = dm

3 = 0,001 m 3

Mg g mg

Mass

m

Kilogram

kg

Ton

t

1 t = 1000 kg = 1 Mg

Minute Hour Day

min h d

1 min = 60 s 1 h = 60 min = 3600 s 1 d = 24 h = 86400 s

Time

t

Second

s

-

1 s

1/s s -1

1/min min -1 km/h

1/ min =

Numbers of revolutions

n

Revs per second

-

Revs per second

60

1 km/h = 1 m/s 3,6

Speed

v

Meter per second

m/s

-

Kilometre per hour

m 3 /h l/min l/s

1 m 3 /h = 16,67 l/min = 0,28 l/s 1 m 3 /s = 60.000 l/min

Flow

V

Cubic meter per second

m 3 /s

-

-

1 N = 1 kg m/s 2 1 kp = 9,81 N = 10 N 1 kp = 1 da N

Force

F

Newton

N

-

-

-

1 N/m 2 = 1 Pa 1 bar = 105 Pa

Newton per square meter Pascal

N/m 2 Pa

-

Bar

bar

Pressure

P

Energy Work Quantity of calories Momentum, torque Pressure Energy absorption Heat absorption

1 J = 1 Nm = 1 Ws = 1 kg m 2 /s 2 1 kWh = 3,6 Mj

W

Joule

J

-

Kilowatt-hour

kWh

M

Newton-meter

Nm

-

-

-

1 kpm = 9,81 Nm

1 W = 1 J/s = 1 Nm/s 1 kpm/s = 9,81 W

P

Watt

W

-

-

-

2 = 1000 mPas

1 Pas = 1 Ns/m 1 cp = 1 mPas -6 m 2 /s 1 cSt = 1 mm 2 /s 1 cST = 10

Dynamic viscosity

Pascal-second

Pas

-

-

-

h (m)

Square meter per second m 2 /s

-

-

-

Kinetic viscosity

u

Temperature

-

Kelvin degree

°k

-

Centrigrade degree °C

-

Frequency

f

Hertz

Hz

-

-

-

-

II.1