Let’s conclude our Temperature Insights educational video blog post series with a look at Temperature Measurement Installation Best Practices. In this 4:42 YouTube video, Emerson’s team managing the Rosemount temperature sensors and transmitters explains how to gain accuracy and reliability in temperature measurement through proper installation techniques.
As a project engineer, it’s important to understand the design decisions made in the selection and procurement of the temperature measurement devices. Four considerations include the thermowell installation, sensor installation, transmitter installation, and system grounding. The thermowell pipe penetration should be in a location that accurately reflects the process temperature and is easily accessible.
Before cutting into the pipe, is draining and cleaning required and all necessary permits/approvals secured? The installation technician should verify the thermowell insertion length into the pipe or vessel and verify that the materials of construction are compatible between the two. Design decisions should also include whether to use threaded, welded, or flanged style of thermowell.
For sensor installation considerations, it important that the sensor make contact with the bottom of the thermowell.
For the transmitter installation, the optimal method, known as direct mounting, is to have the transmitter integrally mounted with the sensor and thermowell. This installation method improves noise immunity through shorter sensor leads and their exposure to environmental electromagnetic interference (EMI). These transmitters can also be mounted remotely, but should be in close proximity to the sensor.
For the mounting location, you’ll want to consider the ability to view the local operator interface display and any environmental issues such as vibration, corrosion, and ambient & process temperatures.
A final consideration is system grounding. Each facility has its own guidelines for proper grounding of plant instrumentation. The three most common guidelines include:
- remote mount with two separate ground points—shield ground at remote sensor housing and distributed control system (DCS)—no ground connection at the transmitter
- Remote mount with a continuous shield
- Integral mount
Getting the installation right the first time can save a lot of expense, reliability issues, and overall efficiency across the operating lifecycle. After the installation is complete, final steps include proper configuration, calibration, and commissioning to connect the measurement devices with the DCS.
You can learn more about these installation best practices by securing your complimentary copy of The Engineer’s Guide to Industrial Temperature measurement. Chapter 4 on engineering and design provides greater detail on these installation best practices.
You can also connect and interact with other temperature measurement professionals in the Temperature track of the Emerson Exchange 365 community.