FAIL-SAFE ELECTRIC ACTUATORS
Where a valve must move to a known position, in the event of electricity failure during power failure conditions, stored energy is essential. If the valve is normally remote controlled, the remote control system will be electric for the following reasons:
- When remote control and standby manual operation is required, the total installed cost of an electric actuator system should be lowest.
- A good electric system is fundamentally more reliable, as it is totally free from the problems of dirt, moisture, and freezing, which affect fluid systems.
- Motorized valves involve no continuously running plant and therefore no plant maintenance routine.
An iVact electric valve actuator already provides all the necessary means for remote electrical control and indication with emergency handwheel operation. iVact electric fail-safe valve actuators simply add a spring mechanism. The spring mechanism will operate the valve when the control signal is removed or during a power failure.
However, there are alternatives to a Failsafe Electric Spring Return Valve Actuator:
- A Battery Backup can provide several valve cycles/operations assuming that the actuator can be operated locally or remotely with an electrical signal. These actuators require the use of DC motors. A typical lifespan for these systems is 3 – 5 years. Since the battery requires venting these actuators can not be used in hazardous environments.
- A Pneumatic or Hydraulic valve actuator with a spring mechanism can provide faster operating times. It is the least expensive if a pneumatic or hydraulic system is already in place.