Global Gypsum (GG): Could you introduce your background and why Sensortech was set up?
Colin Hanson (CH): I graduated with an electronics degree in 1974 while serving a professional apprenticeship with British Aircraft Corporation. After a spell in oil exploration in the 1970s, I joined Shields Instruments, where I was introduced to the field of IR spectroscopy. After six months, Shields was acquired by a US firm that also owned Moisture Register, at that time the only provider of moisture sensors to the gypsum wallboard industry.
I first went over to the US in 1980, to train the staff on the UK-made products. While there, I was offered and accepted the position of engineering manager for Moisture Register. I worked there for around 18 months before it was sold to another new company. As part of my role to improve the product range, I presented a range of instruments I had developed to the new owners. However, they would not invest in the new product line. I believe that, given their dominance at that time in the gypsum board industry, they did not recognise the need for further product investment. That discussion directly led to the establishment of Sensortech Systems by me and two other colleagues in January 1983. We saw the potential for great technological advances in the field of radio frequency (RF) moisture measurement, particularly as applied to gypsum wallboard measurement.
GG: How was Sensortech’s technology different to that of other instrument manufacturers?
CH: The approach is a resonant frequency technique in which the RF antenna couples with the product and resonates at a specific frequency. The frequency depends only on the dielectric constant of the material, which is very moisture dependent. It therefore acts as a good proxy for moisture. Resonance is determined by the product and antenna mechanism and not by electronic components in the measurement circuit. This guarantees long-term stability and reliability. A US patent was issued in 1985.
This approach differs from others, which rely on a power-loss basis, i.e. the amount of electrical energy that is absorbed by the moisture in the wallboard. This sounds okay, but the power-loss is limited to measuring relatively low moisture contents, restricting its use to final kiln zones and take-off. It is influenced unpredictably by many other things, including ions dissolved in the moisture, filler materials and product temperature. RF dielectric is predictably influenced by temperature but relatively unaffected by the other variables. The resonant frequency technique really was a ‘game changer’ in terms of stability, repeatability and the ruggedness of the equipment itself.
GG: How did the company develop?
CH: One of the two other partners, Logan Mosteller, who had helped with the development of the new technology, retired and sold his share to me in 1985. My remaining partner, Bob Blankenship, on the sales and marketing side, left Sensortech and sold his share to me in 1990. I became the sole owner of the company in 1996 when the owners of Moisture Systems Corp sold that company to Thermo Electron and sold their share of Sensortech back to me.
GG: What about technical developments?
CH: We started off with the ST-1100 moisture sensor range. At the core was a 90% analogue instrument with a digital read-out, which was enough to be considered ‘digital’ in the 1980s! The first instrument was sold to USG for its Galena Park, Texas plant. The ST-1100 was manufactured until 1993, during which time we sold 750 units. The ST-2200 was released in 1992. This was a 90% digital instrument, the only analogue parts being the frequency generator and phase detector. We went back to our user base and offered to upgrade their equipment. The ST-2200 resolved dielectric changes 600 times smaller than the ST-1100. The ST-2200 allowed us to expand into low mass products such as wood panels and textiles and other thin products. Around 3500 such systems have been sold to date.
I attended my first Global Gypsum Conference in 2000 in San Francisco presenting a paper titled ‘Maximising Profits with Moisture Measurement & Control.’ At that same conference, a thermal imaging device was unveiled, generating substantial interest. Although not directly correlating to moisture content, it demonstrated the desire for more than just average board moisture. Sensortech responded with the Instantaneous Moisture Profiling System (IMPS-4000) in 2003. More than 100 IMPS systems have been sold worldwide, providing detailed board quality information.
The ST-3300 was released in 2018. The fundamental measurement technology remains the same but makes use of the latest ‘state-of-the-art’ electronics. It is a ‘smart’ sensor with embedded signal processing, connecting directly to plant networks.
GG: How is the company formed as of 2019?
CH: The headquarters are in Oxnard, California, USA. 22 employees do research, development and manufacturing, as well as national sales and administration. There is also Sensortech Systems Europe BV, based in Giessen, The Netherlands, with around 10 technical and sales support personnel. European countries have independent representatives reporting to Giessen. Sensortech Limited in Shanghai, which has another 10 staff, is responsible for China and supports a network of 17 agents throughout Asia. Customers outside of the US, Europe and Asia are handled by independent regional offices.
GG: How important is the wallboard sector to Sensortech these days?
CH: The gypsum sector probably represents 40% of our total business. It is by far the most important sector we cover, representing the majority of our RF sales. We also have a near infra-red (NIR) sensor side, which currently accounts for 60% of all sales.
GG: What happens when a new wallboard client approaches Sensortech?
CH: Typically, a Sensortech representative will visit the plant, as each is different. We have to look at the dryer, the air-flow diagrams, line speed and temperatures to assess what the moisture levels are and where best to provide a useful measurement. A three-zone dryer would typically have two internal sensors, for example at the beginning of zone 2 and 3. Sensors outside the dryer perform a final quality-control check. Final out-of-kiln measurement facilitates dryer balancing.
GG: How long does installation take?
CH: We can deliver standard sensors within 3-4 weeks. Most plants have a down day once a week. Most sensors can be installed during that day.
GG: How much contact does Sensortech retain with customers while sensors are in use?
CH: The instruments require very little maintenance but some is needed. In the past a typical wallboard plant would have a strong in-house technical department performing maintenance. However, these days this is not the case, so Sensortech is becoming more involved. This is particularly the case in Europe, where there is quite an emphasis on service agreements. This is less of a trend in the US, but one that we are working hard to promote.
GG: Do the sensors ‘see’ differences between wallboard made with different types of gypsum?
CH: Our other technology, NIR spectroscopy, has application on raw gypsum and here there are significant differences between natural and synthetic gypsums. This is a relatively new area for Sensortech with potential for controlling processes prior to calcining. Measurement of gypsum purity and degree of calcination is also possible using NIR.
The type of gypsum used is irrelevant after the slurry stage. Sensortech’s RF instruments measure free moisture in the product before, during and after drying, ensuring consistent and optimal drying efficiency.
GG: Where are the main markets for Sensortech at present and is this changing?
CH: Over Sensortech’s first 20 years or so, I would say that the US represented around 60% of our business, with Europe 30% and 10% for the rest of the world. In 2008 things changed dramatically. Europe dropped to 5%. China came to our rescue, purchasing 60% of our products. The US slipped to 35%, across all business.
In recent years, we have seen increase in demand in North America. US business has been booming particularly since 2017. Europe has also picked up in the past two years or so. China, previously very strong, has slowed somewhat for Sensortech in the past five years or so. Today China is around 20%, Europe 30% and the US 50%.
GG: How are the types of clients changing?
CH: There are fewer and fewer small companies in the wallboard industry, indeed there are only a handful left. In Europe there are essentially three players: Saint-Gobain, Knauf and ETEX (Siniat). North America has just four or five major firms and Knauf has recently taken over USG, further consolidating the picture globally.
Consolidation is helpful, when you have a great product and lead the field as Sensortech has been able to do. Fewer customers makes business more straightforward. However, we will not be complacent and risk losing that dominance. There is always someone waiting to fill the void, as Sensortech did in 1983.
GG: How are clients’ demands changing?
CH: It is no longer enough to simply produce systems that report and store information. Clients want the systems to be networkable and linked to data collection systems with enhanced features to help facilitate real-time control. A lot of our time is currently spent working to optimise the usability of the systems and software along such lines.
The industry would like measurements that are independent of board weight and thickness. Any one plant might make 30 types of board. They would like our sensors to measure moisture independent of physical properties. At present they must calibrate the sensors to each of the board types. A pragmatic approach is to target set-points on an arbitrary scale. One type of board might be ‘good’ at 35 arbitrary units, while the target for a lighter board might be ‘18-20.’ A system that automatically calibrates to the different types of board would be very welcome indeed.
GG: What’s in the pipeline from a technology standpoint?
CH: This is not a ‘sales-pitch’ but we really are constantly improving our products. We are working on new systems that are easier to install with lower maintenance requirements. We have the Kiln Jam Detector, which I am certain will be a boon to all board plants whose emphasis is on higher throughput and ever-lighter boards. Payback for this product may be measured in the prevention of just one major kiln jam. It is currently undergoing tests at a gypsum wallboard plant in North Carolina, US.
GG: Sensortech Systems was recently bought by KPM Analytics. How will this change the company on a day-to-day basis?
CH: On a day-to-day basis little has changed. I remain President of Sensortech, but I now answer to other bosses. I will continue to manage the Oxnard facility while handing over various administrative functions to the new owners. The first thing that impressed me with KPM was the importance they placed on people, not just products. We have a depth of talent within Sensortech, further supplemented by KPM, that I feel confident will provide a seamless transition to a successful future.
GG: How has the transition been so far, from a personal perspective?
CH: The sale process started in October 2018 and due diligence, with all it involved, I found incredibly taxing. The deal closed on 14 May 2019 and left me feeling ‘empty.’ The last time I felt this way was having graduated from University. What had been my raison d’être for so long had been lifted from my shoulders. I am now 67-years old and have worked in this field for the past 40 years. I am looking forward to retirement in a year or so, but expect to be very busy throughout this transition.
In the longer-term future, KPM will put resources into growing Sensortech, which is fantastic. We have a development queue representing years of research at our current pace. There are opportunities to accelerate that with funding from KPM and, of course, with the right people. There are also potential synergies and opportunities to work with other companies in KPM group in similar fields to Sensortech. One example, already enacted, is the integration of Process Sensors’ RF products with those of Sensortech. Sensortech will immediately take over the support for existing PSC RF products and, going forward, all RF sensor products will carry the Sensortech label.
GG: Thank you for your time today. We wish you all the best in your ‘new position.’
CH: You are very welcome indeed!
