June 2020

suppliers need to be long-term partners. “We got solid reliability from SICK from the beginning. They have adapted their technology, provided training and support for us and our customers, and they have grown to understand our process very well.” Standardisation Standardisation of instrumentation has been a continuing journey across the entire Byworth boiler range, explains Atkinson. This not only benefits customers, but also optimises the company’s own operational efficiency: “The boiler industry is quite a conservative industry, so sometimes we have to push a little to recommend using the best technologies. We have driven out traditional boiler instrument suppliers to put SICK sensors on our equipment. “We use SICK’s PBS pressure sensors to control the hot well tank level, as well as to regulate steam pressure output from the boiler. The SICK PBS is a transmitter with two switch points. So, instead of having 3 or 4 different instruments, we could use one instrument on two different boiler designs. This also helped us move away from 230V and 110V towards a standard 24V DC control architecture. Not only does this save energy, space and reduce wiring, but the SICK PBS pressure transmitters are all on M12 plug connectors, which makes it easier for our service engineers. They are just plug and play.” The SICK PBS’s on-sensor display enabled Byworth to reposition the pressure reading on the hot water feed, from the top of the tank to a workable, eye-level height. For many customers, the PBS’s added analogue output has also proved an advantage, and again reduced the need to install another separate sensor. Guided wave radar Perhaps the greatest technology step-change came when SICK introduced a new guided wave radar technology, which Atkinson recognised could be used for sensing water level in the boiler. Until the arrival of SICK’s LFP Inox sensor, Byworth had used either a capacitive sensor or a float system for continuous level measurement of water in the boiler. The capacitive sensor technology proved to be sensitive to foam and the float system sensitive to turbulence in the boiler. The SICK LFP Inox overcame both of these challenges as it is neither sensitive to water foaming when being poured into the boiler or turbulence. “The LFP guided wave radar gives us a much more reliable, accurate level, so we can run our feedwater system much more tightly,” says Atkinson. “We do not get so many swings in water level. The more the water level fluctuates, the less heat efficient the system is.” SICK was able to develop a firmware adaptation for the LFP to meet the combined requirements of a sensor insensitive to foam and turbulence with a display that is easily accessible to a boiler operator or service engineer. Not only did this mean the Byworth LFPs could be standardised on a 1.3 metre probe length, but the LFP’s amplifier system offered a solution to separating probe and electronics to give operators easier access to the display. So, the LFP in-tank probe is connected remotely to the sensor and emitter via a flexible coaxial cable which can be up to 3.3 metres long. Trials Byworth’s successful trials of the SICK Dosic ultrasonic flow sensor confirmed its competitiveness and accuracy, so it has been introduced for feed tank metering on the smaller boiler range. Because feedwater has often undergone a reverse osmosis process, it can have a very low conductivity, so a magnetic flow meter could not be used. The Dosic has also proved useful for fuel oil metering. Meanwhile, trials have recently completed to use SICK’s new calorimetric FTS thermal flow switch to monitor flow in the softener drains. Standardising and rationalising into one central control was the concept behind Byworth’s Unity digital control system, which won a Queen’s Award for Enterprise in Innovation in 2016. Traditionally boilers have evolved with individual control systems for different parts of the boiler. “On the Unity systems we have done studies that demonstrate fuel savings of 7% annually, over and above what is achieved just by installing new plant. That’s based around how we control everything from one unit in the boiler house, rather than in separate, individual processes - how we sequence boilers, how we modulate them, how we bring them online and so on,” says Atkinson. “Standardising on sensors helps us to control the data coming from different parts of the boiler house a lot more finely. Of course, we are looking for accuracy, reliability and repeatability of measurement, too. “Instruments like the guided wave radar were a hard sell for us to begin with, and we had to explain our rationale for using suppliers not traditionally associated with the boiler industry. But now those technologies are being asked for by customers and specified for new boilers. We have had to drive that change through. “Our relationship with SICK has been a mutually beneficial partnership, where both companies have ended up with a better product.” For further information please visit: www.sick.co.uk www.byworth.co.uk 30 | Plant & Works Engineering www.pwemag.co.uk June 2020 Energy, the Environment & Water Focus on: Boilers, Burners & Controls