New Surface Sensor Innovation Achieves Accurate Process Temperature Measurement Overcoming Challenges of Traditional Methods

by Ryan Leino, Emerson Automation Solutions, Rosemount Temperature Product Manager

As you know, temperature is the most commonly measured variable in the process industry. It’s often a critical factor in determining process efficiency and product quality. There are several ways to measure temperature in the process industry and each one has challenges. I’d like to tell you about a new type of surface sensor technology that can overcome some of these issues for you.

A thermowell and temperature sensor assembly is the most frequently used method of measuring a temperature internal to a process. A thermowell is a component of a temperature measurement point that acts as a protective barrier between the temperature sensor and process. It enables insertion of the temperature sensor into the process where it might not otherwise survive the harsh conditions present. The direct sensor immersion of thermowells into the process helps provide an accurate measurement, but introduces a possible leak point, which is a significant problem.

An alternative sensing method, surface temperature measurement, alleviates many of the pains associated with a thermowell installation as it does not require direct contact with the process. Since the measurement point is external to the process being measured, there is no threat of internal conditions physically damaging it or creating potential leak points. The need for wake frequency calculations and other complex design considerations are eliminated.

Although a traditional surface temperature measurement installation addresses many of these pains and challenges, in many cases it cannot match the measurement performance of a thermowell installation. If an internal process temperature measurement is required, a surface temperature measurement is often not capable of providing an accurate or repeatable representation of an internal measurement.

There are many factors that can impact a traditional surface temperature measurement reading. This makes it difficult to use as a simple point of inference when determining the temperature of the associated internal process. However, by implementing an algorithm with an understanding of the thermal conductive properties of the temperature measurement assembly and corresponding piping or vessel, a surface temperature sensor solution can be utilized to accurately calculate internal process temperature. This unique technology works by measuring the pipe surface temperature and ambient temperature, and combining this information with an understanding of the thermal conductivity properties of the installation and process piping.

In order to understand the unique design of this surface temperature measurement capability which Emerson calls Rosemount X-well™ technology, please access this interesting white paper.

Rosemount X-well Technology offers accurate process temperature measurement without requiring any intrusions or penetrations into the process, eliminating possible leak points, and allowing quicker and easier installation, along with simplified long-term maintenance. Users do not have to design, size, or maintain thermowells. Wake frequency calculations are eliminated, as well as time spent determining material compatibility, the right insertion length, and the necessary profile.

With this innovation, users can also add temperature measurement points without having to shut down a process. It can be installed with a standard pipe clamp procedure and ordinary hand tools, and does not require a skilled contractor.

The surface measurement innovation works best in steady state applications, including the majority of pipe processes –

  • Pipeline monitoring
  • Small line size applications
  • Retrofit projects that need new points
  • Pipeline requiring frequent cleaning
  • High velocities
  • Slurries and heavy particulate fluids
  • Clean-In-Place (CIP) processes
  • High viscosity fluids
  • Harsh processes requiring exotic materials

In the following industries –

  • Oil and gas
  • Chemical
  • Refining
  • Life sciences
  • Metals and mining
  • Pulp and paper

If you have any questions, or if you’ve encountered applications where surface temperature measurement could be effective, please contact me at Ryan.Leino@emerson.com.

And don’t forget to access your free white paper.

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