The temperature shown by a coolant controller is not automatically the temperature of the entire chill roll surface. Surface temperature depends on the incoming material, contact, heat flow through the roll, coolant conditions and the operating state. Define the location, timing and test conditions before comparing temperature readings.
What affects the result?
The coolant's inlet temperature and flow, the internal passage arrangement, pressure losses, surface condition and heat load can all affect the temperature distribution. Web width, line speed, material temperature and contact area matter too. A temperature difference may arise from the supply system or process rather than the roll alone.
Build a measurement plan
Agree on positions across the working face, measurement method, machine speed, coolant inlet and outlet conditions, load and stabilization criteria. Record ambient conditions where relevant. A contact probe or infrared device must be suitable for the surface and used according to its instructions; infrared readings are sensitive to emissivity and reflections, especially on shiny metal. Do not access an operating nip or touch a moving roll.
Look for the cause before changing the design
Compare readings at the same positions and conditions. Check the coolant supply, strainers and control system in accordance with the equipment manufacturer's safe maintenance procedure. Review uneven web contact or changes in product width as well. Internal flow passages and sealing arrangements are design choices, not guarantees of a particular temperature distribution.
Enquiry checklist
Send the roller drawing, medium, inlet temperature and flow, allowable pressure, operating load, temperature targets, measurement locations and observed defects. For cast film, include the material and line configuration. Qichao can review manufacturing or repair requirements; cooling performance and suitable construction must be confirmed for the project.