There are two main drivers for partial stroking of valves in safety systems: the desire to extend manual test intervals to as long as possible; and to reduce the amount of redundant hardware required for higher safety integrity levels. Like most things in life, it all boils down to one thing: trying to save money.
Understanding the fundamentals of fluid agitation can help meet the customers requirement and the processors need for efficiency. While portable mixers have been around for years, they often arent used to their full potential. Knowing the basics of mixing and flow patterns can help you get more out of your mixer.
Author: David Dickey, MixTech, Inc. and Lydia Booth Fenley, Illes Seasonings & Flavors
In this month's installment of On the Bus, Contributing Editor John Rezabek predicts HART devices will work so well that your career may be over before you can justify the cost to replace them with fieldbus.
Understanding the purpose of control and safety systems helps users ensure each is appropriately optimized. The duties of the SIS are to protect the people, environment and assets against unsafe conditions.
Author: Angela Summers, PhD, PE, founder of SIS-TECH Solutions
More and more companies are placing greater emphasis on maintenance and seeking help from vendors to boost the effectiveness of their efforts, as some recent major investment decisions demonstrate. Many automation companies now are benefiting by building up asset management services alongside process control capabilities.
Fieldbus has proven its merit in bringing projects online more efficiently, allowing better diagnostics, and control, and reducing maintenance costs and inventories. However, it has been limited in intrinsically safe services. At last, technology has come through once again with a solution. The capacity barrier of FISCO has now been significantly surpassed by a novel split architecture design that has already proven itself in the field.
Classic distributed control systems typically remain only in high-availability refining and power applications, but their strategies and capabilities persist in descendants and todays sophisticated networks.
Your current control system can probably do more than you think. Everybody can agree that diagnostics are a good thing they can identify problems early, and keep the plant running at peak performance. Learn how your existing control systems and analog instruments can deliver diagnostic capabilities, at a fraction of the cost of system or instrument replacements.
More attention to steam systems and trap monitoring provides big benefits. At most chemical plants, plant management and operators face increasing pressures to improve the energy efficiency of their processes, so they should see how they can save on steam.
Increasing interest will translate into far more monitoring applications. The worldwide market for wireless technology will grow 26% annually over the next few years, forecasts the ARC Advisory Group. Vendors are responding and key concerns are being addressed.
Design provides improved reliability in a polymer-precursor batch reactor. Sensors must respond quickly and survive a harsh environment. Poor probe reliability can make the difference between a process that makes money and one that doesnt.
The New Sampling/Sensor Initiative or NeSSI that replaces tubing, fittings and other hardware in a sampling system with miniature modular components makes sense. Enhancements now in the works should assure its success.
Handling slurries (a mix of solids and liquids), should be based on experience and experiments, not theory. Much of the knowledge obtained from pneumatic conveyors and fluidization systems can be used in understanding slurries.
Author: Thomas R. Blackwood, Healthsite Associates
This article looks at six technologies mechanical floats and displacers, differential pressure, capacitance, ultrasonic, radar, and guided wave radar that are used most often for automated control, and provides practical guidance for choosing among them.
Author: Jerry Boisvert, Siemens Energy & Automation