Thermowells

Thermowells

Thermowells are the process-wetted mechanical protection elements that isolate a temperature sensor insert from harsh process conditions. They protect against high pressure, high-velocity flow, and corrosive substances while preserving the ability to measure temperature accurately. A primary operational advantage is that the measurement insert can be replaced without interrupting the process, supporting higher availability and safer maintenance practices.

Thermowell selection is strongly influenced by design standards, manufacturing approach, and plant certification requirements. Portfolio descriptions emphasize construction types (welded, barstock, or forged), a wide range of industrial and hygienic process connections (threaded, flanged, weld‑in, socket weld, compression fitting, clamp, and others), broad material choices from stainless steels to high alloys and ceramics, and options with or without an extension neck. Common design references include DIN 43772, ASME B40.9, and NAMUR NE 170.

Different construction methods align to different priorities. Welded thermowells fabricated from tubes are described as cost‑effective with high design flexibility and a variety of material options, while barstock thermowells machined from a single piece of metal are suitable across many applications depending on material and dimensions. Specialized geometries (e.g., helical designs for high-velocity services) address vibration and wake-frequency concerns in demanding flow regimes.

Hygienic thermowell execution can be as important as industrial strength in many facilities. Examples noted include hygienic thermowells for aseptic applications and hygienic elbow thermowells designed without welds or dead legs, including quick‑release extension concepts. These designs support cleanability and reduce crevice risks while maintaining mechanical protection and serviceability.

Typical applications include any temperature point where process conditions would quickly degrade an unprotected sensor - high pressure, high velocity, erosive/corrosive media, or extreme temperature cycling - and any service where sensor replacement without shutdown is valuable. They are also used as retrofit hardware to upgrade measurement durability, and they are foundational in engineered high-temperature and hygienic assemblies where mechanical integrity and standards compliance are design drivers.

Field Instruments & Controls, Inc. an exclusive authorized representative of sales and service for Endress+Hauser.