This article describes a Load cell system for constantly weighing cables. The system solved the weighing of molten copper in the pour-pot that formed part of a closed loop, constant head, continuous casting control system.
This load cell system gives constant weighing for cables A task that confronted Ron Dilsworth, the Engineering Manager at Pirelli Cables was the weighing of molten copper in the pour-pot that formed part of a closed loop, constant head, continuous casting control system.
The need was to control the weight of molten copper in the pour pot to keep it constant and to control the in/out flow rate for continuous casting out to the mould.
The task arose because the existing load cell weighing system was inaccurate and not repeatable, making it impossible to run the system in the automatic mode.
In the end, the question came down to whether to go back to the original suppliers via a third party in the States, or to change the system for a new one that the company sourced itself.
After considering the options, it was decided that the best solution was to source the system itself and to redesign the brackets and fixings to accommodate a Thermo Nobel KIS shear force load cell system.
Pirelli Cables was attracted to Thermo Nobel as it had previously supplied it with a reliable weighing system and, because of its hands-on involvement, the company's engineers were easy to contact, and the system offered was potentially very accurate and repeatable.
Ron Dilsworth at Pirelli Cables designed these brackets, with the same principles used by Thermo Nobel with its standard mounting brackets for its KIS load cells, but taking into account the space available and its base plate fixtures.
The Thermo Nobel weighing system comprises four KIS 1 50kN shear force load cells and a TAD 3 weighing processor indicator.
Among the benefits of using KIS load cells are that they are immune to errors from side loads up to 100%, while their repeatability and combined error performance is excellent.
These points, plus the fact that overload ratings are 100%, made them ideal for this application.
The TAD 3 is intended for converting signals from strain gauge based load cells and force transducers into suitable indication or for PC or PLC based systems.
It is very accurate, and has excellent connectivity and operator's interface - hence one of the attractions to Pirelli's engineer.
The result is that Pirelli Cables is now able to weigh exactly what is in the pour pot to a high degree of accuracy and is now able to run its continuous casting process in automatic weighing mode.
Respective topics: Performance of onboard weighing systems Weighing Accuracy Load Cells Weighing Systems