B-505-UK-11-2013 REV. B
An
Company
Type 505 Spring Return - Sizing
Sizing - Spring Return Actuators
Spring Mounting Form for Spring Return Actuators
The suggested safety factor for spring return actuators under normal working conditions is 30% - 50%.
Example:
• The torque needed by valve = 80 Nm.
• The torque considered safety factor (1 + 30%) = 104 Nm.
• Air supply = 5 bar.
According to the output torque table on spring return actuators, we find the output torque to be:
• Air stroke 0° = 308 Nm.
• Air stroke 90° = 247 Nm.
• Spring stroke 0° = 181 Nm.
• Spring stroke 90° = 120 Nm.
All the output torques are higher than needed.
5 Springs
9 Springs
6 Springs
10 Springs
7 Springs
11 Springs
8 Springs
12 Springs
DVC standard
The most reasonable and economical actuators
If we know the torque needed by the valve while working at opening, operating and closing, we can choose the most
reasonable and economical actuator.
Example:
• The maximum torque needed by the butterfly valve = 104 Nm.
• The torque after opened (operating) 104 x 30% = 32 Nm.
• Air supply = 5 bar.
We can select the Model 125 Spring Return when the output torque is:
• Air stroke 0° = 136 Nm > 104 Nm.
• Air stroke 90° = 78 Nm > 32 Nm.
• Spring stroke 0° = 173 Nm > 32 Nm.
• Spring stroke 90° = 115 Nm > 104 Nm.
• The above data shows that the actuator torque can meet the requirements of the butterfly valve.
Valves with a difference
11
