Published 27 August 2026 at 13:17
Measuring surface temperature on a stationary object is straightforward. Measuring on a surface passing by at one hundred meters per minute is another matter, and a standard contact probe fails in two ways simultaneously.
It scratches — the tip drags a line along the path, which is unacceptable on a printed, coated, or polished surface. And it heats up, because the friction between the probe and the material generates heat precisely at the point being measured. After a while, you are practically measuring your own mark.
What it is
A roller probe — a temperature sensor housed in a wheel, designed for moving surfaces.
- PTFE wheel, 50 x 45 mm (also available in stainless steel)
- Maximum speed 100 meters per minute
- Response time under two seconds
- Measurement range -75 to +250 °C
- Type K thermocouple, accuracy according to BS EN 60584-1
The wheel eliminates relative motion
This is the entire concept. A wheel rolling against the web moves at the same speed as the surface where they meet — the contact point is therefore stationary relative to the material, even though the material is moving past. No slipping, hence no scratching and no friction heat.
At the same time, the contact is constantly renewed: a new wheel surface meets a new material surface, lap after lap. This is why a roller probe can maintain a fast response time despite working against something that is constantly changing — it does not measure a single point over time, but a sequence of points.
The figure of 100 meters per minute is therefore not a detail but the definition of the application. Above that speed, the wheel cannot keep up, the contact becomes uneven, and the reading ceases to describe the surface. This is the first thing you should check against your own line speed.
PTFE or steel — a real choice
The wheel material determines what you prioritize. PTFE is soft and releases most materials; it does not mark a printed or coated surface and is suitable where the product is sensitive. Stainless steel conducts heat significantly better and withstands more wear — it provides faster response and longer lifespan, but is harder on the material it rolls on.
The fact that the probe is available in both configurations makes the choice explicit rather than implied: protect the product, or measure faster and replace the wheel less often.
And one thing worth knowing: the wheel has its own temperature. If it comes from room air and is placed against a hot web, it takes a moment before the reading describes the surface instead of the wheel. This is exactly what the response time indicates — and the reason you let the probe roll for a while before noting the value.
Three typical use cases
- Web and roll: paper, film, foil, and laminate during drying or cooling.
- Rolling mills and calenders: surface temperature on rollers in operation.
- Conveyors: products in motion where a handheld measurement would otherwise have to be done during a stop.
Why it pays off
The surface temperature of a web almost always controls something: adhesion, drying, curing, shrinkage, or how the product behaves in the next step. Yet it is often only measured when the line is standing still — and then it is no longer the same temperature, because the web has stopped moving through the heat zones.
A measurement that can be taken during operation therefore provides not just a number, but the right number. And it can be repeated, directly after an adjustment, which transforms the setup of a line from a series of guesses into a sequence of measurements.
