25 Years Working in the Valve Position Monitoring Industry

Paul Turner, Engineering Manager, Imtex Controls Ltd

The realisation that 2018 represented the 25th anniversary of my starting full time employment in the Valve Position Monitoring Industry arrived with an element of shock a few weeks ago

This was partly due to the fact my ego refuses to accept that I might be ‘getting on a bit’ now (although my kids are more than keen to ensure my ego is regularly put back in its place) but also that I never imagined in 1993 as a recent engineering graduate that the Valve Position Monitoring Industry could possibly hold my interest for that long! My youthful self was very wrong!

As this 25th year begins, I have naturally been reflecting on what has and hasn’t changed over the years and where the industry is likely to head in the future. Whilst on the face of it little has changed – the ubiquitous ‘2 switches in a box’ is still by far the largest volume product in the industry – there have been some distinct trends that have risen, and occasional fallen away, over the years. Here are 5 that I have noticed:

1. The move to ‘engineered products’ for Valve Position Monitoring – In 1993 there was still a large number of automated valves that didn’t have any feedback to confirm valve position and, where they did, this was often provided by exposed switches fitted directly to the actuator and terminated into a separate junction box. Where an enclosure was provided for the switches, this was often a crude, off-the-shelf box that some customisation was done to. When I started out, many of my sales visits involved selling the benefits of product specifically designed for valve position monitoring with features like visual indicators, easy set systems for the switches and integral termination points. These type of units are now very much the Industry standard.

2. The rise – and decline? – of fieldbus systems – The late 1990s saw considerable interest in the use of fieldbus systems for valve position monitoring, primarily due to the potential savings in terms of cabling. The attraction is obvious – if you can run one 2 or 4 core cable to multiple valve position monitors rather than an individual 4 or 6 core cable to each and every monitor that the potential cost savings are large. However a number of issues such as the complexity of getting systems to work reliably, a lack of a clear universal standard protocol and the potential for the loss of feedback on a large scale meant that significant momentum never gathered for implementation in the Industry. In addition, in terms of valve position monitors which are relatively simple feedback devices, many of the protocols available are over complex and expensive for the application.

3. The increased use of transmitters – Analogue transmitter position feedback from on/off valves was relatively rare in the 1990s as it was seen as an overkill for the application. However, over the last 10 to 15 years I have noticed a distinct increase in the number of transmitters supplied for on/off valves. The main reasons for this are twofold. 1) Using a 4-20mA transmitter in place of 2 limit switches on a valve means less I/O required on a site 2) the continuous nature of the feedback makes it much easier to identify when a valve is causing an issue or the feedback is last.

4. One enclosure required to provide multiple feedback modes – Back when I started in the Industry, it was very rare that a Valve Position Monitor was required to have more than a single pair of switches fitted. Occasionally, a request for a unit with two DPDT switches (essentially two ‘normal’ SPDT switches packaged in one switch) would be received to allow feedback to two control systems but these were rare. As the years have past, I have seen an ever increasing demand for more feedback from individual monitor units. This includes multiple switches or a combination of multiple switches and transmitters. At Imtex, we regularly supply monitors with a 4-20mA transmitter and 4 switches which allow discreet feedback to, say, a Process Control System and an Emergency Shutdown System whilst also offering an input to a diagnostic system.

5. The increased requirement for condition monitoring – Building on trend 4, recent years has seen a distinct demand for valve position monitors to form part of a condition monitoring system for the valves on which they are installed. In a number of industries such as Oil and Gas testing regimes such as Partial Stroke Testing are becoming increasingly prevalent as well as a desire to identify issues with valves before they become critical. As a ‘monitoring’ device, the valve position monitor plays an important role in this more general condition monitoring requirement and I can only see this role growing.

At Imtex, this has meant that we are building much greater functionality into our monitors that allow them to become a diagnostic tool to the end user as they strive to make their plants ‘smarter’. These units are a long way from being just a simple ‘two switches in a box’ position monitor!

So these are my five trends. It is by no means exhaustive and there are many more that I have seen since I started in the Industry and could comment on.

Whilst the biggest volume in the Industry remains a two, wired switch solution – and this solution will continue to remain dominant for the foreseeable future – some of the ‘niche’ trends above will increase their market penetration.

In addition, new technology such as wireless feedback loom just over the horizon and suggest the possibility of a significant shift to the focus of the Industry in the future.

25 years from now I will be 72 years old, and, given the current progression of retirement ages, will very likely still be working. Will I still be in the Valve Position Monitoring Industry? Who knows, but, if it continues to develop and challenge as it has over the last 25 years, I see no reason why not!

Tel: 08700 340 002
Email: sales@imtex-controls.com
Web: www.imtex-controls.com

Published in Valve User Magazine Issue 45


Summer 2018 // Issue 45
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