A temperature sensor that works well in a food plant or a commercial building will not necessarily last in a steel plant. Here, the sensor head can be exposed to radiant heat from the furnace, fine dust works its way into terminal gaps, and vibration from heavy machinery travels down the pipework. Many cases of jumping readings or early sensor failure turn out to come from how the sensor was installed, not from the sensor itself.
The first challenge is heat around the measuring point. The sensing element is designed for the process temperature, but the terminal head and any transmitter mounted inside it have a much lower operating limit. Near a furnace or ladle, radiant heat can make the sensor head far hotter than the surrounding air. The usual fixes are a longer extension neck to move the head away from the hot surface, an added radiation shield, or a transmitter mounted separately in a cooler location.
Dust is the second problem. Iron ore, coke, and mill scale dust is very fine, and some of it conducts electricity. Once inside the terminals, it can cause unstable readings or corrosion at the cable connections. The sensor head and transmitter enclosure should carry an adequate protection rating, with tightly fitted cable glands and covers that are always closed properly after inspection.
Vibration is often underestimated. In the rolling mill or near large pumps, constant vibration can crack the sensing element or loosen cable connections. A properly sized thermowell, cable supports, and a mineral-insulated sensor construction, which handles vibration better, all help the sensor last longer.
Electrical interference is the challenge most specific to steel plants, especially around the EAF and high-power motors. Signal cables laid alongside power cables can pick up noise, so the reading on screen moves up and down while the process temperature is actually steady. Use shielded cable grounded at one end, route it away from power cables, and mount the temperature transmitter as close to the sensor as possible. Once the signal is converted to 4–20 mA, it is far more resistant to interference on its way to the control room.
Position and insertion depth also decide accuracy. A sensor in a cooling water pipe needs to reach well into the flow, not just touch the pipe wall, so it reads the temperature of the medium. Avoid points with dead flow or spots too close to a local heat source that does not represent the process.
Finally, plan for maintenance from the start. A thermowell lets the sensor be removed for inspection or replacement without stopping the process flow. For critical points, periodic checks against a reference instrument help make sure the data reaching the control system can still be trusted.
CV. Rach Tekindo Makmur supplies Temperature Sensors & Temperature Transmitters for a wide range of industrial instrumentation needs. If you need sensors, transmitters, or consultation on configuration and installation for your temperature system, contact us on WhatsApp at 0877-8620-5656 to discuss your technical requirements and request a quotation tailored to your application.
