Rust, corrosion, dirt, flaking paint, water ingress and external integrity impaired by aggressive products, would all be high up on any process engineer's list of typical application problems for valves in process industries – including hygienic processing sectors such as pharmaceuticals, and food and beverages. Many would say that these industries have, for too long, been plagued by these problems, to the extent that they have learned to live with them.
Now, however, the limitations of conventional control valve solutions in the control of steam, fluids, gases and aggressive media have been thoroughly and systematically analysed by Burkert. The result of this evaluation is the Element series of control valves.
The innovative features of these attractive, clean line, stainless steel valves meet the challenges of process industries and offer solutions to problems that many users have hitherto accepted as system-intrinsic.
As an added benefit, the valves also satisfy the pressing industry need to reduce energy use. Thanks to intelligent internal design, the air consumption to actuate Element valves is up to 40% lower than conventional process valve systems.
The bodies of these valves are manufactured exclusively from high-quality stainless steel, a material that not only saves on weight, but also considerably enhances the aesthetics of the valves. In comparison with other materials, stainless steel is a convincing choice, as its cast integrity is high. This means that the walls of the Element valves can be optimised, reducing their overall weight and size envelope. Moreover, the impact resistance of stainless steel can be up to 25 times higher than other materials. This all adds up to more lightweight, compact and robust valve bodies.
The use of stainless steel also offers longer-term advantages. When the finish on most conventional valves has been damaged by exposure to harsh process environments, the Element valves still retain their original attractive appearance.
Designed to IP 65/67 protection class, the valves, with their heat and chemical resistant design, easily withstand the rinsing and cleaning processes required in processing plants. The clean, sleek external lines ensure the valves are easy to clean and also stay cleaner for longer.
The interior of the Element control valves proves that outer appearance and inner values are not mutually exclusive. There are a number of innovative key operating areas.
First, high-gloss polished valve stems minimise friction and maximise the service life of the automatic self-adjusting seals.
Second, the valve stroke position feedback transducer is not only integrated within the valve, but is also contact-less. Consequently, it never blocks or wears out, and always remains accurate because it measures the linear stroke motion directly without conversion.
Third, because the feedback transducer is fully protected inside the valve, the requirement for external linkages, nuts, bolts and connections is eliminated. This innovation dramatically reduces the areas where product can accumulate and cause contamination.
Fourth, the control air is also routed internally, without the need for awkward external hoses.
A further innovation on the Element units is valve actuator control, which is achieved by means of the integrated pilot valves that can also be actuated manually for easy local operation. For each operation, clean and dry control air is deliberately flushed into all areas of the actuator. This ensures that, unlike traditional solutions, ambient air is never drawn into the spring chambers and surrounding voids, extending the valve's reliability and life, at the same time maximising process availability for the valve user. In addition, as no impurities or moisture are drawn into the actuator, there can be no corrosion of the springs inside the actuator. The same feature also prevents the risk of biological growth, which could result in contamination of the process environment as a whole.
Burkert has also deployed new design thinking to provide protection against moisture ingress into the electronics of the control heads on the Element valves. Protection is required because small but naturally occurring changes in the control head pressure can lead to the penetration of moisture, particularly after a wash down cleaning process.
Diverting a small amount of clean control air into the control head, maintaining a slight positive pressure, and thus achieving a simple and innovative solution, is a defence against this ingress.
In addition to their many operational benefits, the Element valves offer optimised interactiveness with the user. The valves integrate a modern operator concept that is intuitive and user-friendly, in spite of the extensive range of relevant functions provided. To prevent data overload, additional functions are displayed only as required, and the configuration of positioners and process controllers is seamless and automatic. Local communication is achieved at a glance via a high performance and highly visible, multicoloured LED display that illuminates the surrounding area, passing on immediate user information regarding the valve status. Finally, all-important data logging information is displayed on a backlit graphic display.
The integrated intelligence in the Element units also means that communication outside of the local sphere is easy to achieve. With the Element control valves series, Burkert offers a complete automation concept for integration into most commonly used control systems. Using options such as Profibus DPV1, ASI and Device NET, possible applications range from monitoring simple control tasks and the integration into complex field bus solutions, through to the complete decentralisation of a plant-wide automation system.
The new valves are part of Burkert's Element system, which has set a higher benchmark in process measurement and control. This provides a complete systems approach, linking clean line valves, sensors, positioners and valve actuators in a simple architecture to solve total control loop processes. With unlimited modularity, Element saves processing time by offering total control solutions for media from slurries to steam, and from de-ionised water to hydrochloric acid.
Burkert meets challenges of process industries with Element control valve
The valve is attractive, clean line, stainless steel and helps cut energy use
