How the process sector is reaping the benefits of the latest generation of smart positioners
Process industries often depend on high performance valve actuation in harsh environments. Despite the difficult surroundings, process plants demand the latest technology, such as smart positioners, which allow technicians to use auto-calibration and simple diagnostics to commission and monitor their entire system at the push of a button. In many cases, the valve, actuator and smart positioner package is exposed to extreme temperatures, dirty conditions and other challenges such as high vibration.
Most instrumentation positioners would fail quickly when subjected to these harsh environments. For example, smart positioners require internal electrical components that are extremely vulnerable at high temperatures and may prematurely fail when exposed. Young Tech Company (YTC) has therefore developed two smart positioner solutions to cope with the conditions associated with tough process control applications.
Remote sensing unit positioners
The YT-3301 introduces the concept of isolating and detaching the sensing feedback portion of the positioner from the main control housing. The sensing unit accurately detects the position of the valve stem and provides a feedback signal to the main housing. This dual-unit design allows the operator to locate the precision electronics elements at a considerable distance from the valve environment, providing the best of both worlds – precision engagement at the point of valve movement and a clean, dry and ambient temperature for the electronics. This also facilitates mounting multiple control housings in close proximity for convenient and time saving monitoring and adjustment of valves in the plant.
Triple module remote positioners
Remotely mounting the sensing unit provides dramatically improved reliability and performance, but at longer distances between the sensing unit and the control housing pneumatic signal loss may occur. In extreme situations this could lead to hunting and oscillation of the electronics and reduced valve and actuator positional stability.
To assure the performance in these difficult applications, YTC has developed the YT-3302 Positioner. With this product a third module, housing the driving components of the pilot valve and torque motor assembly, is mounted at an intermediate location between the remote sensing unit and the main control unit. Accordingly, the three modules are the sensing unit, driving unit and control housing. As the sensing unit contains the most robust components and the control the most sensitive, this configuration delivers higher performance, increased positional accuracy and longterm reliability.
Added benefits include the ease of maintenance for each of the modules and the ability to gang mount modules at convenient locations. Standardisation of modules and components can also facilitate spare part simplification and inventory cost reduction.
For more information, visit www.engineerlive.com/epe
YTC is a member of the Rotork Group of flow control companies.