Sarclad specifies robust Penny + Giles tilt and rotary sensors
January 11th 2012

Penny + Giles, a business group of Curtiss-Wright Controls and designer and manufacturer of high precision sensing technology, is supplying its STT280 tilt sensors and SRH280DP rotary sensors to Sarclad to provide critical measurements for an In-Chain Strand Condition Monitor – a precision, online measurement system used to monitor continuous casting machine rolls used in the steel making process.

The In-Chain Strand Condition Monitor (In-Chain SCM) is permanently installed in the steelmaking process to enable automatic fixed-roll alignment and roll-gap measurements to be performed at the beginning of every casting, without affecting production activities.

The Penny + Giles sensors were specified to meet the stringent requirements of a system that is robustly engineered to endure the extremely hostile casting environment.

Commenting for Sarclad, In-Chain SCM manager Richard Cowlishaw says: “With a continuous cast system able to produce in excess of $1million worth of steel a day time is of the essence, so interrupting production to measure the condition of the casting machine could cost steelmakers huge amounts of money. Installing a Sarclad In-Chain SCM system ensures that measurements are taken automatically at the start of every cast, so that costly downtime is avoided and quality of product is maintained.”

The Penny + Giles STT280 tilt sensors are fitted to the In-Chain SCM to measure the fixed-roll alignment of the casting machine using spring-loaded blades that tangent pairs of rolls to measure the angles between them. The data is then processed to identify rolls and segments that are out of position relative to other rolls within each segment.

Sarclad had previously used inclinometers, but specified the Penny + Giles tilt sensor because its compact size and extremely robust construction proved more effective and robust for the application. In addition, because measurements are taken while the continuous cast system is moving, inclinometers were prone to resonate or create a spike output. In contrast, the STT280 tilt sensor features 3D MEMS technology, which provides a naturally-damped response that is unaffected by knocking or vibration. This feature is especially important for continuous steelmaking operations where accurate measurements are vital, as Richard Cowlishaw explains.

“The steel making process involves pouring molten steel into a caster mould and oscillating the mould to prevent the liquid steel sticking to the sides while it solidifies. The vibrations from the action of the oscillator affects the measurements taken with traditional inclinometers, by producing spiked rather than smooth outputs, which corrupts the measured data.

The caster operates from ninety degrees vertical to zero degrees horizontal, so in order to accurately measure between the two angles it is necessary to measure beyond them. Penny + Giles were able to customise the STT280 sensor to measure between 92 degrees and -2 degrees, providing the calibration points we needed outside the measuring range.”

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