FAIL-SAFE… that's the way it works - safe, even without a spring!
For a customer in bulk materials handling, we developed and built this cylinder-valve unit.
A compressed air tank mounted directly on the cylinder ensures that, in the event of a pressure drop, the cylinder moves to its safe default position by pressurizing one of the actuator's chambers. The system can be used for both linear and rotary actuators, but offers particular advantages for large linear actuators.
Design:
- A double-acting cylinder is controlled via a 5/2-way solenoid valve with a mechanic spring (combined spring). The use of a monostable solenoid valve with combined spring-return ensures fail-safe operation in the event of a power failure. (view HAFNER solenoid valves with NAMUR interface)
- In the event of pressure loss, the intermediate flange valve type PN 611 611 switches over. The compressed air stored in the tank moves the cylinder into the fail-safe position. (view HAFNER block- and vent valves with NAMUR interface)
- When the air supply returns, the tank automatically refills.
- The ZVP adapter plate enables optimal mounting on the cylinder, reduced piping effort, and improved switching times. (view HAFNER adapter plates for linear actuators)