A T T U A T O R I
.
- PNEUMATIC ACTUATORS AND ACCESSORIES -
UsermanING ISSUE .10 March 2004
GT ATTUATORI S.r.l.
REA MI 1558400
FAX (02) 90390368
V.le Europa 17 - 20090 Cusago
Partita IVA e Cod.Fisc.12449540157
TEL (02) 90390322
Milan - ITALY-
E-mail [email protected]
www.gtrevisan.it
PAG. 17 OF 20
INSTALLATION
OPERATION &
MAINTENANCE MANUAL
11.0
ACTUATOR SIZING
Prior to actuate sizing it is important to get certain information. Key numbers to get are as
follows:
- Torque required to open the valve.
- Torque required to close the valve.
- Actuator air pressure.
- Differential pressure of Valve/Damper.
Obtaining the above information allow you to properly and effectively size a SPRING RETURN
actuator. ( NOTE: DOUBLE ACTING actuators have a constant torque throughout their entire stroke ).
When determining the air supply pressure it is important thet you use the
minimum
air pressure
that the actuator will experience and not the average air supply pressure.
If an actuator is supplied by a lower air pressure than it is sized for, failure or improper
performances can occur.
12.0
AIR T0 AIR ACTUATORS
12.1 -
Select the largest torque ( opening or closing torque ) and, increase that number of 10%.
( NOTE: Adding 10% is done to ensure an acceptable factor of safety).
The data published in the sizing table indicates
average
capacity for that given pressure.
12.2
- Using above-mentioned sizing table, look in the column that corresponds to the supply pressure
you have selected. Move down the chart until you have found a torque which is
larger
than the torque
determined for your application.
After you have found the correct value, move across the table horizzontally to determine the correct
actuator.
13.0
SPRING RETURN ACTUATOR
13.1
- Increase both your valve closing torque and your valve opening torque by 20%. ( Again this
will provide an acceptable factor of safety ).
NOTE: THE VALVE CLOSING TORQUE CORRESPONDS TO
THE SPRINGS END COLUMN
AND THE VALVE OPENING TORQUE CORRESPONDS TO
THE ACTUATOR AIR PRESSURE COLUMN
