Xiatech T8500 Extended-Reach Platinum Resistance Thermometer (PRT)
| Brand | Xiatech |
|---|---|
| Origin | Shaanxi, China |
| Model | T8500 |
| Probe Diameter | Φ5 mm |
| Probe Length | 3–4 m (customizable) |
| Lead Configuration | 4-wire |
| Lead Length | 2 m |
| Temperature Range | 0–50 °C |
| Accuracy Class | A (T8501 variant) / B (T8502 variant) |
| Sensing Length | 2.6–3 m |
| Recommended Excitation Current | 1 mA |
| Long-Term Stability | ≤0.01 Ω/year |
| Short-Term Stability | ±0.01 °C |
| Sheath Material | Inconel Alloy |
Overview
The Xiatech T8500 is an extended-reach, high-stability platinum resistance thermometer (PRT) engineered for continuous, high-fidelity temperature monitoring in demanding industrial heat exchange environments—particularly condenser seawater outlet lines in thermal power plants. Based on the IEC 60751:2022 standard for platinum resistance thermometers, the T8500 employs a Pt100 sensing element housed within a hermetically sealed, corrosion-resistant Inconel 600 sheath. Its extended probe geometry (3–4 m) enables direct immersion into flowing seawater streams without requiring intrusive piping modifications or external cooling jackets. The device operates on the fundamental principle that the electrical resistance of high-purity platinum varies predictably and reproducibly with temperature, allowing traceable, drift-compensated measurements across its 0–50 °C operational range—a critical window for condenser thermal performance evaluation per ASME PTC 12.2 and IAPWS-IF97 thermodynamic benchmarks.
Key Features
- Extended probe design (3–4 m customizable length) optimized for deep insertion into large-diameter condenser discharge pipes, minimizing flow disturbance and boundary-layer error.
- Inconel 600 alloy sheath provides exceptional resistance to chloride-induced pitting and stress corrosion cracking in seawater service—validated per ASTM G48 Method A.
- 4-wire Kelvin connection eliminates lead resistance error, ensuring measurement integrity over 2 m cable runs without compensation algorithms.
- A-class accuracy (IEC 60751:2022) available in T8501 configuration (±(0.15 + 0.002|t|) °C), supporting regulatory-grade data logging for plant efficiency reporting.
- Long-term stability specification of ≤0.01 Ω/year translates to <0.026 °C drift over five years—enabling extended calibration intervals aligned with ISO/IEC 17025:2017 uncertainty budgeting.
- Fixed 1 mA excitation current ensures low self-heating (<0.005 °C at 50 °C in seawater), preserving measurement fidelity in low-velocity flow conditions.
Sample Compatibility & Compliance
The T8500 is validated for direct immersion in natural seawater, brackish water, and treated cooling water systems with conductivity up to 55 mS/cm and suspended solids <100 ppm. It complies with IEC 60751:2022 (Pt100 tolerance classes), IP68 ingress protection (submersible to 10 m depth), and RoHS 2011/65/EU material restrictions. For nuclear or regulated utility applications, the sensor meets ASME NQA-1 requirements for Class 3 instrumentation when integrated with qualified signal conditioners and documented calibration procedures. Traceable calibration certificates (NIST-traceable reference standards) are provided with each unit, including full uncertainty budgets per ISO/IEC 17025.
Software & Data Management
The T8500 is compatible with industry-standard 4–20 mA transmitters (e.g., WIKA T32, Endress+Hauser TMT182), digital bus interfaces (HART, Modbus RTU), and DAQ systems supporting IEEE 1451.2 TEDS templates. When paired with Xiatech’s optional TCAL-Link software suite, users can perform automated calibration verification, generate audit-ready calibration reports compliant with FDA 21 CFR Part 11 (electronic signatures, change control logs), and export time-synchronized datasets in CSV/Excel format. All raw resistance values (Ω) are retained alongside compensated temperature outputs, enabling retrospective reprocessing using updated ITS-90 polynomial coefficients.
Applications
- Real-time monitoring of condenser seawater outlet temperature for thermal efficiency calculation (ηcond = 1 − Tcold,in/Thot,out) per ASME PTC 12.2.
- Performance trending of surface condensers in coal-, gas-, and nuclear-fired power stations.
- Validation of computational fluid dynamics (CFD) models simulating tube bundle thermal distribution.
- Baseline reference sensor for validating infrared thermography surveys of condenser shell surfaces.
- Integration into distributed control systems (DCS) for automatic turbine load derating triggers when outlet temperature exceeds ASME-designated thresholds.
FAQ
What is the maximum allowable immersion depth for the T8500 in seawater?
The probe is rated IP68 for continuous submersion to 10 meters depth; however, mechanical anchoring and flow-induced vibration must be assessed per site-specific hydraulic conditions.
Can the T8500 be recalibrated in-field without removal from the pipe?
No—recalibration requires controlled dry-well or liquid-bath comparison against a certified reference PRT; field verification may be performed using portable secondary standards per ISO/IEC 17025 Clause 6.6.
Is the 4-wire lead set shielded and twisted-pair?
Yes—the standard 2 m lead assembly uses individually shielded, twisted-pair copper conductors with overall foil + braid shielding, meeting EN 61000-6-2 immunity requirements.
Does Xiatech provide installation torque specifications for the process connection?
Yes—mounting flange torque is specified as 25 ± 2 N·m for DN50 PN16 connections; detailed installation drawings and hydrotest protocols are included in the OEM manual.
How does the T8500 handle thermal shock during rapid seawater temperature transients?
The Inconel sheath and optimized stem conduction path limit thermal lag to <12 s (63% response) in 1 m/s flow, verified per IEC 60751 Annex D step-response testing.
