The mining industry poses unique challenges for maintaining plant uptime. Facility managers are accustomed to attributing root failure to the facility’s instrument air systems.
However, a thorough root cause analysis reveals that pneumatic actuators fail regardless of how clean the instrument air is.
Poor environment air quality, such as in underground mining, will lead to the premature expiration of pneumatic actuators. It’s simply a flaw in all spring-return pneumatic actuators.
The good news is that in recent years, actuator manufacturers like Easytork have updated the design for actuators, effectively addressing the space, cost and clean-air challenges posed by mines and mills, and directly resulting in less downtime and lower maintenance costs.
Historically, emergency shutdown actuators have used springs as a fail-safe mechanism. However, as actuator experts are well aware, the problem with this design is that spring-based fail-safe actuators are only ideally suited for pristine environment and instrument air – a nearly impossible standard for the mining industry to meet. With sub-par instrument air, exposed metals inside the actuator are exposed to corrosion.
The problems don’t end there. The actuator’s spring action vacuums in contaminants from the environment. Debris from the environment air attacks the soft sealing of the actuator, creating leakage points, and moisture from the environment air exposes the springs to corrosion.
The new generation of actuators replaces springs with an internal air reservoir. The air reservoir is placed into the pneumatic actuator housing and stores the compressed air needed to supply the required force to switch the valve to its fail-safe position.
Just like a spring, the reservoir is constantly pressurised and available to perform the fail-safe operation during a power failure or catastrophic air failure. Unlike spring-based designs, however, the new generation of actuators do not need to be oversized to overcome the spring tension and the required torque of the valve and system.
This simple design upgrade results in one clean package that is 30 to 50% smaller, more than 50% lighter, more cost-efficient, and simply operates better in mines and mills, providing the same fail-safe security.
Using air reservoirs for the fail-safe operation also decreases maintenance costs. With actuators that use air reservoirs, environment air becomes a non-issue; with no springs, it is impossible for the actuator to create a vacuum to suck in environment debris and moisture.
The result is an actuator that is 100% immune to environment air and also has improved resistance to poor instrument air. The new actuator models also require 30 to 50% less instrument air.
This is a big win for mines and mills - the decreased air consumption calls for smaller capital expenditure on instrument air systems. In addition, the actuators’ more compact size addresses the space limitations that mines and mills are constantly running up against.
The new generation of actuators – absent of springs and an external air reservoir – is especially crucial in mining applications. The small devices reduce total cost of ownership by consuming significantly less air; they also reduce issues associated with poor air supply.