When working with flammable and hazardous materials, pneumatically actuated quarter-turn valves are preferred over electrical or motorized actuator, reducing the potential for electrical sparks. Any pneumatic valve equipped with a FireChek thermal shutoff from Assured Automation will shut down without the need for any external signal or power, the company says, as its shape-memory alloy responds to the ambient temperature.
The FM-approved FireChek thermal shutoffs with resettable memory shape alloy are said to quickly responds to heat in the event of a fire and automatically exhausts pressure in the actuator to close the supply line.
When the ambient temperature reaches 135°, 150° or 165°F, the thermal shutoff’s memory shape alloy undergoes a phase induction change, and rapidly produces the force and motion to shift the valve.
When the device senses excessive heat from a nearby fire, it immediately closes the air supply line preventing the air from feeding the fire. It simultaneously vents the spring return actuator to allow the return to fail-safe.
Because the thermal shutoff responds to heat, not flame, it is said to offer dramatically improved protection compared with conventional plastic tubing burn-through.