Valve Positioners: Swap to Smart

Business today is very competitive and each industry is deriving ways to bring to the market the best products at the lowest prices, without compromising on the standards. In this scenario, it is imperative to manufacture the same, or better, products at lower prices. Techniques like predictive maintenance can help manage costly assets and reduce total cost of ownership, thereby bringing down overall costs.

The proper flow control of high energy steam or compressed air or speciality chemicals or even gas is an important aspect where a loss or excess of as little as 0.5 bar pressure would amount to substantial financial losses. Proper valve positioning can help address these issues. Smart positioners are no doubt, swifter, more efficient and cost effective when it comes to accurate control in comparison to the conventional E/P Positioner. With the advent of proactive maintenance and smart manufacturing, the smart positioner is gaining importance.

Here’s why:

Low Air Consumption

Smart positioners consume almost 90% less air than a non-smart valve positioner and gives a healthy return on investment within 12-18 months. This makes the smart positioner a strong alternative especially when it comes to reducing overheads.

Adjusting Flow Characteristics

Gone are the days when one had to change the valve trim and seat in order to are minimal friction losses since it compares the position feedback and rapid corrective measures are taken for friction losses to avoid “positional losses”.

Addresses a variety of process requirements

Smart positioners provide several avenues of adjustment in order to optimize performance of the control valve:

  • Control action: Direct or reverse direction can be opted for at the valve level which requires no changes in DDC

Valve diagnostics
The valve diagnostic feature is characteristic of a smart positioner and is very useful in troubleshooting and maintenance operations as it helps detect valve leaks, reduced valve travel, etc. Its parameters are useful to schedule periodic maintenance as they help detect severity of problem, thus ensuring that proactive action is taken. It has parameters like:

  • Time constant for damping feedback sensor — To identify the need for re-calibration of valve position
  •  Number of changes in direction gives understanding of process stability and helps determine hunting
  • Operational time function helps in maintenance planning
  • Valve limit position (Seat worn-out) is useful for estimating leakages, and
  • Valve positioning time helps in adjusting loop tuning parameters or adding attachments.

With the advent of proactive maintenance and smart manufacturing, the smart positioner is gaining importance, says Vinod Joshi.

The valve diagnostic feature allows the integration of the positioner as a part of the predictive maintenance programs to limit costly failures, to proactively service the parts, and to reduce unscheduled plant shutdowns.

Furthermore, the Asset Management System utilises the smart positioner’s valve diagnostic feature to determine asset characteristics such as performance and cost of ownership. It is also used to determine future valve spares investment projections and spares availability and its planning. Furthermore, the asset management system can perform vendor comparison by comparing performance such as leakage, etc., using this feature. With all the aforementioned benefits, one cannot dismiss the crucial role that a smart positioner plays in industry

Contributed by :

Vinod Joshi