Surface Thermometers

Surface Thermometers

Surface thermometers are non-invasive temperature instruments that determine the medium temperature by contacting only the outer surface of a pipe, reactor, or vessel. Because the process boundary is not penetrated, the measurement can often be added to existing equipment without welding in a nozzle or opening the line, making it a practical option for retrofit monitoring and temporary studies.

Non-invasive measurement is broadly applicable, but it is particularly attractive in heavy-duty industrial processes where process conditions make intrusive measurement difficult or where the risk and cost of process penetration are high. These instruments can be positioned flexibly at multiple points on a single line or across different lines in a plant, supporting targeted coverage where temperature insight is most valuable.

Benefits include reduced installation time, minimized leak-path creation, and the ability to add measurements while avoiding disruption to the process. For energy management, clamp-on measurement enables rapid deployment of temperature points needed for heat-balance validation, efficiency monitoring, or verification of insulation performance. For safety, it provides an additional layer of temperature awareness on critical equipment where overheating or unexpected thermal excursions must be detected.

Performance depends on thermal coupling to the surface, pipe/vessel material and thickness, insulation configuration, ambient influences, and installation repeatability. Good practice is to ensure consistent contact pressure, manage heat loss at the mounting point, and validate the measurement against a reference during commissioning when high absolute accuracy is required. When these considerations are addressed, non-invasive sensing can provide robust trending and actionable diagnostics.

Typical applications include retrofit temperature monitoring on steam and condensate lines, hot oil and thermal fluid systems, heat tracing verification, and temporary measurements during commissioning, troubleshooting, and energy audits. They are also used on reactors and vessels where adding a new process penetration is impractical, enabling additional safety and performance monitoring without invasive work.

Miller Mechanical Specialties, an exclusive authorized representative of sales and service for Endress+Hauser.