Instrumentation and process automation company Endress+ Hauser is recoding tempera- tures in roll neck bearings – used in a rolling mill – by implementing its wireless solution, the WirelessHART, to optimise plant efficiency for a heavy plate manufacturer.
By installing the WirelessHART solution, the company explains, the client is now producing more than 880 000 t/y of heavy plate, ranging from 5 mm to 125 mm in thickness.
Endress+Hauser notes that it retrofitted the wireless solution at a lower cost than expected and is confident that the plant now has an optimum overview of the status of the roll neck bearings. The client can now also maintain the system and replace the bearings according to schedule, regardless of any faults.
Endress+Hauser temperature system components product manager Benjamin Mlangeni notes that the implementation of the WirelessHART solution has resulted in predictive maintenance intervention, as it detects any damage to, and thereby protects, the extremely costly friction bearings.
The company notes that the heavy plate manufacturer’s plant comprises two work rolls, which reshape the steel slabs directly, and two backup rolls, which transfer toll pressure to the work rolls. The four-high stand has a maxi- mum rolling force of 80 000 kN. This was considered a challenge as the roll neck bearings are located on the operating and drive sides of the upper and lower backup rolls, which adds pressure to the rolling force of the neck bearings.
The backup rolls are known as morgoil friction bearings. A lubrication circuit ensures that they receive the proper lubrication, while the temperature of this circuit is monitored at the inlet and outlet.
An increase in the temperature differential indicates a higher degree of friction inside the bearings, which might result in damage. However, the ambient conditions that add pressure at the rolling stand make it difficult to wire up the necessary temperature sensors securely.
To mitigate this challenge, Mlangeni says, each tempera- ture sensor is fitted with an adapter, which allows for wireless data transmission based on the WirelessHART standard. For temperature measurement, Endress+Hauser TR15 resistance thermometers, each with a weld-in thermowell and replaceable insert, were used.
“As a result of space limitations and possibly restricted radio communication between products, installing the adapter directly on the temperature sensor is not advised,” he notes.
The adapter is, therefore, installed remotely and connected to the temperature sensor using a short cable. The adapter also powers the connected device using its built-in battery.
Each adapter works as a transmitter and receiver, ensuring that data can be transmitted to the WirelessHART gateway, even if direct radio communication is not possible.