Thermowells

Thermowells

Thermowells are the process-wetted protective components of a thermometer assembly, shielding the temperature sensor insert from harsh process conditions such as high pressure, high-velocity flow, and corrosive substances. They also enable the measuring insert to be replaced without interrupting the process, a key lifecycle advantage where uptime, safety, and maintenance accessibility are critical. Endress+Hauser notes that thermowell design, manufacturing methods, industry standards, and plant certification requirements all influence thermowell selection.

Endress+Hauser describes a broad portfolio that includes welded, barstock, and forged designs, with extensive process connection options spanning industrial and hygienic interfaces (threaded, flanged, weld-in, socket weld, compression fittings, clamp, and more). Material choices range from stainless steels through alloys to ceramics, and configurations may include extension neck options. Design standards referenced include DIN 43772, ASME B40.9, and NAMUR NE 170, supporting alignment with established mechanical and documentation expectations.

The benefits of thermowells extend beyond basic protection. By isolating the sensing element from mechanical loading and chemical exposure, thermowells can extend sensor life, reduce failure frequency, and improve maintenance safety by allowing insert replacement under process conditions. Standardized thermowell strategies also support repeatability in mechanical design and spare parts, reducing variation across similar lines and services.

Applications include high-pressure piping, high-velocity services, corrosive chemical duties, and abrasive processes where direct sensor exposure would be short-lived. Endress+Hauser references a helical iTHERM TwistWell design intended for high-velocity applications and highlights hygienic thermowell solutions for food/beverage and pharmaceutical services, including designs described as having no welds or dead legs and incorporating quick-release extension neck concepts for maintainability.

Engineering rigor is essential: Endress+Hauser explicitly notes thermowell sizing/strength calculation to verify structural integrity and suitability for the intended process conditions, considering material properties, geometry, and operating conditions. Ordering approaches can be structured as a pre-assembled thermometer + thermowell unit, as separately ordered components for project flexibility, or as stand-alone thermowells for spares and retrofits. These options support both new-build and lifecycle replacement strategies while maintaining mechanical compliance.

At Eastern Controls, We are proud to be the exclusive authorized sales and service representative for Endress+Hauser.