Technology overview

Thin film tip design

ifm uses a highly engineered construction method. The RTD element is first bonded to a thin film carrier. This reduces the thermal mass of the electrical leads. The film carrier and RTD element is then attached to a specialized assembly carrier. The carrier positions the RTD element into precisely the correct location and preloads the RTD with constant force against the probe’s inner sheath wall. This allows the RTD element direct and constant controlled contact to the sheath, minimizing the amount of thermal mass separating the RTD element from the process media. The result – fast and repeatable response!

Ordinary RTDs and temperature instruments have the sensing element potted into the tip of the sheath tube. The potting compound acts like an insulator, slowing the heat transfer to the RTD element. Typically, the RTD element location is not controlled, but simply lowered by its lead wires into the sheath and glued into place. Both of these factors lead to poor uniformity, repeatability and response time.

ifm's TA23xx and TA26xx sensors use this thin film tip design.

Metallic bonded tip

This ifm design uses a revolutionary process that metallically bonds the RTD element directly onto the copper-plated inner wall of the probe tip. This creates very low thermal mass with a direct metallic bond for optimal heat transfer. The metallic bond technology eliminates all polymer parts allowing the sensor to be used at higher temperatures. Additionally the tip construction offers response speeds twice as fast as our already fast thin film design.

The metallic bonded construction is great for:

• UHT (Ultra High Temperature) pasteurization processes
• HTST (High Temperature Short Time) pasteurization processes
• SIP (Steam-in-Place) measurement
• Continuous processes where fast reaction speed and critical temperature measurement is required

ifm's TA22xx sensors use this technology and they are rated to 200 ºC.