FLOWX Engineer 86-21-54150349
Pneumatic actuators application in severe conditions is critical for safe, dependable and efficient running of power plants. Such critical applications must be considered differently from general service pneumatic actuators because these applications have their own particular set of demands for good long-term performance. The performance confining of pneumatic actuators application in severe conditions is apparently a function of the technologies in them. Discussion on pneumatic actuators application in severe conditions is presented to help the application of right technology in such critical services.
Standards for pneumatic actuators have evolved over time as in other industries. The main object of these standards has been to make sure safety of the public and of the device, consistency in sizing for flow capacity and for ease of installation. The standards generally command minimum design practices for safe operation under all the known operating conditions, with adequate margin of safety. Typically, this includes pressure-boundary integrity and mechanical stresses, thinking both static and dynamic conditions.
The standards for pneumatic actuators do not provide obvious performance guidelines, nor do they offer any design rules for minimizing potential for challenges in a given application. This makes option of pneumatic actuators application in severe conditions all the more crucial.
The pivotal in dealing severe service valve problems is the technology. Due to the nature of such applications, it becomes crucial to identify the results of off-design conditions. While valves in general service category are often available off-the-shelf, such a method for application in severe conditions is hazardous.
The most credible way of removing problems is by addressing the root cause(s).
Discerning the root cause of the problems is the first procedure in ensuring that the technology in the valve is proper for the specific application, whether in existing valves or in terms of potential in new application. As illustrated earlier, all pneumatic electric actuators application in severe conditions are not exactly the same. However, most of the causes of problems in application in severe conditions fall in five categories:
excessive fluid energy along the flow path
inadequacies in actuation system
poor maintenance/improper adjusting
The last matter of maintenance and calibration is not a valve technology related issue. No amount of maintenance or adjusting will offset the shortfall in performance due to the first four items shown above. Most crucially, it should not be used, or admitted to be used, as an excuse for successive valve problems.
In order to avoid the problems of pneumatic actuators application in severe conditions, it is necessary to estimate if the technology in it is proper for the specific application.
Generic guidelines, which cover quantitative and verifiable design rules, that deal the root cause of problems of pneumatic actuators application in severe conditions are available. Adherence to these rules narrows the choice of technologies to those that would result in good long-term term performance, high reliability and dispel the MWe losses connected with these valve applications.
Finally, incorporation of particular design rules in the actuator specification offers target and verifiable criteria that can be applied to test the quality of the technology for good actuators performance in service.