RTD Element with Aluminum Head for Thermowell, 9in Long

Precision Temperature Measurement: RTD Element for Thermowell Applications

This advanced RTD (Resistance Temperature Detector) element is specifically engineered for use within a thermowell, providing robust and highly accurate temperature measurement in demanding industrial environments. The specified configuration includes a 100 Ohm Platinum RTD, housed within a 1/4-inch OD Sheath that is 9 inches long, featuring a 1/2-inch NPT Stainless Steel Hex Fitting, and an Aluminum Head and Block.

Understanding RTD Technology Resistance Temperature Detectors, often referred to as resistance thermometers, are renowned for their exceptional accuracy, repeatability, and interchangeability. They operate on the principle that the electrical resistance of certain metallic elements changes predictably with temperature. In industrial applications, platinum (Pt) is the material of choice due to its linear resistance-temperature relationship, chemical inertness, and stability. A small excitation current is passed through the element, and the resulting voltage (proportional to resistance) is precisely measured and converted into temperature readings. RTD elements are typically manufactured by either winding a fine wire (wire-wound) or depositing a thin film (thin-film) onto a ceramic or glass core, then sealing it within a protective capsule.

Key Specifications and Their Importance:

• For Thermowell Application: A thermowell acts as a protective barrier, isolating the RTD from the process medium. This allows for sensor replacement or calibration without shutting down the process, while also protecting the delicate sensing element from high pressure, corrosive fluids, or abrasive flow.
• 100 Ohm Platinum (Pt100): This is the most common and widely recognized standard for industrial RTDs (IEC 60751). The 100-ohm resistance at 0°C provides a good balance of sensitivity, stability, and signal integrity, making it suitable for a broad range of applications requiring high accuracy.
• 1/4-inch OD Sheath: This robust outer diameter provides excellent mechanical strength and protection for the RTD element. It offers a balance between durability and response time, ensuring the sensor can withstand typical industrial conditions while accurately tracking temperature changes.
• 9-inch Length: The specific immersion length is critical for accurate temperature sensing. This dimension ensures the RTD's sensing tip extends sufficiently into the process stream within the thermowell to obtain a representative temperature measurement.
• 1/2-inch NPT Stainless Steel Hex Fitting: The 1/2-inch NPT (National Pipe Taper) thread provides a secure and leak-tight connection to the thermowell or process vessel. The Stainless Steel (SS) construction ensures superior corrosion resistance, high-temperature capability, and mechanical strength, making it ideal for harsh industrial environments. The hex shape facilitates easy installation and removal with standard tools.
• Aluminum Head and Block: The aluminum head provides robust protection for the RTD's terminal connections from environmental factors such as moisture, dust, and mechanical impact. It often includes an IP (Ingress Protection) rating, indicating its resistance to solids and liquids. The block provides a stable mounting point for the head and internal wiring.

Optimized Performance Through Lead Wire Compensation: Given the relatively low initial resistance of 100 Ohm RTDs and their small change in resistance per degree of temperature, lead wire resistance can significantly impact accuracy, especially over longer cable runs. To mitigate this, this RTD is designed for connection using three or four-wire configurations. These advanced wiring setups effectively compensate for lead wire resistance, ensuring that only the change in the RTD element's resistance is measured, delivering unparalleled accuracy. RTDs operate across a wide temperature range, typically from -200°C to 600°C (-328°F to 1112°F), depending on the specific element and protective sheathing.

Pyromation's Expertise in RTD Solutions: Pyromation is a leading manufacturer of high-quality resistance temperature detectors and resistance thermometers tailored for diverse industrial applications, including chemical processing, petrochemical, food and beverage, pharmaceutical, and power generation. We offer a comprehensive range of solutions, from single- or dual-element RTDs, various platinum resistance standards (e.g., Pt100, Pt1000), to specialized Sanitary CIP (Clean-in-Place) configurations.

Should your specific application require a unique design not found in our extensive catalog, our experienced product engineers excel in developing custom RTD measurement devices. This includes designing complete temperature sensor assemblies incorporating specialized connection heads, precisely matched thermowells, and integrated transmitters to provide a complete, optimized sensing solution for your needs.