High Temperature Thermometers

High Temperature Thermometers

High temperature thermometers are thermocouple‑based instruments engineered for processes where conventional RTDs and standard protection tubes would rapidly degrade. They pair suitable thermocouple elements with robust protection systems - often ceramic or special alloy thermowells/protection tubes - to withstand extreme radiant heat, aggressive atmospheres, and severe thermal cycling. These assemblies are designed to deliver stable measurement at elevated temperatures while protecting the sensing element from mechanical and chemical attack.

The benefit of purpose‑built high‑temperature construction is service life and measurement continuity. Protection tubes shield the thermocouple from erosive or corrosive process gases, particulate loading, and rapid temperature shocks, reducing drift and unplanned replacement. When the sensor is properly protected and matched to the process, temperature control loops can be maintained with tighter stability, improving product quality and reducing energy waste in high‑heat operations.

Selection typically starts with the thermocouple type and metallurgy. Base‑metal thermocouples (such as J, K, or N) may be suitable for many high‑temperature duties, while noble‑metal thermocouples (such as B, S, or R based on platinum/rhodium) are applied where even higher temperatures or better long‑term stability are required. The protection system is then engineered with ceramic materials or high‑performance alloys, and paired with threaded, compression, or flanged process connections as the mechanical interface demands.

Typical applications include steel treatment and metal processing furnaces, glass melting and refining, flue gas measurement in thermal processing and combustion systems, and kilns used in brick and ceramics manufacturing. Similar requirements occur in incineration, refractory-lined reactors, and other high‑heat zones where access is limited and sensor replacement is costly. In these environments, robust assemblies reduce the frequency of intervention while maintaining the temperature signal needed for safe operation.

Engineering considerations include immersion depth, protection tube design for thermal shock resistance, and allowance for differential expansion between the protection tube, insert, and mounting hardware. Where signal conditioning is required, transmitters may be integrated locally or mounted remotely to protect electronics from heat while still delivering a standardized output to the control system.

Engineered Equipment Company, a leading supplier of specialized industrial equipment.