BL617 Standard Platinum Resistance Thermometer (-200...420℃)
The Standard Platinum Resistance Thermometer (SPRT) is a kind of device to measure temperature through a change in electrical resistance of a length of wire. SPRT is the stipulated interpolation instrument for realizing the International Temperature Scale of 1990 between the defining fixed points, over the range from 13.8033 K (the triple point of equilibrium-hydrogen, -259.3467 °C) to 961.78 °C (the freezing point of silver). The transfer function of the SPRT is electrical resistance as a function of temperature. Therefore, an accurate measurement of resistance, referred to a fixed resistance base, is an essential component of the measurement chain.
KEY FEATURES
Ranges from -200°C to 420°C
Metal or fused quartz sheathed
W(Ga)≥ 1.11807, W(Hg) ≤ 0.844235
Resistance at 0°C(Rtpw): 25Ω or 100Ω、
Meets all ITS-90 requirements
APPLICATIONS
Reference thermometer for very accurate temperaturemeasurements
Comparative calibration in tube furnaces and liquid baths
SPECIFICATION
Part Number | BL617-N / BL617-0 | BL617-1 | BL617-2 |
Annual drift @0.01°C | ≤ 0.5mk | ≤ 1mk | ≤ 3mk |
Stability | ≤ 2mk | ≤ 4mk | ≤ 8mk |
| Self-heating | ≤ 1.5mk | ≤ 2.5mk | ≤ 3mk |
| Temperature Range | (-200~0)°C，(0~420)°C | -200°C to 420°C | -200°C to 420°C |
| Rtpw | 25.5Ω ± 0.5 Ω | ||
Resistance ratio | W(Ga)≥ 1.11807, W(Hg) ≤ 0.844235 | ||
Measurement Current | 1mA | ||
Platinum diameter | 0.05mm | ||
Sensor length | 60mm | ||
Sensor material | Platinum | ||
Head diameter | φ21mm | ||
Head length | 103mm | ||
Sheath diameter | φ7 ±0.5mm | ||
Sheath length | 470 ±10mm | ||
Sheath material | Quartz | ||
Insulation Resistance | >1000 MΩ at room temperature | ||
Characterizations | ITS-90, IEC-751(DIN 385) | ||
Cable | 2m PTFE insulated copper wire cable | ||
Connection leads | Four Gold-plated Copper Spades | ||
Gas in sheath | Inert gas | ||
SCOPE OF DELIVERY
BL617 Standard platinum resistance thermometer
Wooden carrying case
OPTIONAL ACCESSORIES AND SERVCIE
ISO17025 Calibration Certificate (P/N: CAL-617)
Readout device
Mental sheath SPRT, -200°C to 420°C, ≤ 8 mk stability, 100Ω (P/N: BL617-M-100)
ORDERING MODEL #
BL617-N: SPRT, -200°C to 0°C, ≤ 2mk stability
BL617-0: SPRT, 0°C to 420°C, ≤ 2mk stability
BL617-1: SPRT, -200°C to 420°C, ≤ 4 mk stability
BL617-2: SPRT, -200°C to 420°C, ≤ 8 mk stability
What is the difference for SPRT, reference PRT and Industrial PRT?
Definitions:
Standard Platinum Resistance Thermometer (SPRT): ITS 90 International Temperature Scale transfer standard， applied for metrology institute value dissemination, calibration of reference platinum resistance thermometers and various precision temperature measuring instruments.
Reference Platinum Resistance Thermometer (PRT): Laboratory / calibration equipment built-in standard probe, used for comparative verification in constant temperature baths, field calibration with process calibrators, and inspection of industrial sensors.
Industrial PRT: High-precision temperature measurement in industrial sites, including Class A, 1/10DIN, 1/3DIN grades, widely used in industrial control, pharmaceutical, new energy, precision equipment temperature measurement scenarios.
Comparison sheet:
Item | SPRT | Reference PRT | Industrial PRT |
Range | -189.3442℃ ~ +419.527℃ -189.3442℃ ~ +660.323℃ 0℃ ~ +961.78℃ 13.8K ~ 100℃ | -200℃ ~ +420℃ -200℃ ~ +660℃ | Regular: -200℃ ~ +650℃ Class A: -50℃~300℃; Class B: -200℃~850℃ |
Resistance | Rtp = 25Ω; optional 2.5Ω, 100Ω. (WGa≥1.11807) | 100Ω (PT100); Optional 25Ω. | Mainly PT100 (100Ω @ 0℃), optional PT1000, IEC 60751 standard, α=0.003851/℃ |
Stability | Primary: ≤2mK; 1st Class: ≤4mK; 2nd Class: ≤8Mk; | ≤7mK~10mK ＜0.015℃/24h | 1/10DIN: ±0.03℃; Class A: ±0.15℃; 1/3DIN: ±0.05℃ |
Self-heating | Extremely low: ＜0.001K/mW | Low: 0.001~0.005K/mW | 0.01~0.05K/mW |
Annual Drift | Primary: ≤0.5mK; 1st Class: ≤1mK; 2nd Class: ≤3Mk; | 0.01~0.03℃/year | 1/3 DIN: 0.05~0.15℃/year; Class A: 0.2~0.5℃/year, |
Sensor Material | High-purity drawn platinum wire (99.9999% 6N high-purity). | 5N~6N high-purity platinum wire wound element with stress-free encapsulated winding, balancing stability and portability | Thin-film platinum chip or 5N platinum wire winding, industrial stress-resistant packaging with anti-vibration and shock resistance |
Sheath | High-purity quartz | Inconel Mental | 316L stainless steel |
Filling Gas | Hermetically sealed with high-purity dry argon, deoxygenated under vacuum to prevent platinum wire oxidation at high temperature, filled with magnesium oxide insulating filler | Sealed with dry high-purity argon for inert gas protection, tightly filled with magnesium oxide insulating powder | No inflatable sealing, compactly filled with magnesium oxide insulating powder; anti-corrosion type adopts vacuum packaging without protective gas |
Reference Price | USD2K ~ USD30K | USD500~ USD2K | USD50~ USD500 |
Supplementary Key Difference Explanation
1. Essential Difference in ResistanceDesign
SPRT rarely adopt 100Ω, with 25Ω as the mainstream specification, which greatly reduces self-heating effect and long-term temperature drift, fully complying with ITS-90 temperature scale indexing rules.
Reference PRT belong to working standards. To meet calibration universality, most are designed as industrial general PT100, which can be directly matched with process calibrators and precision thermometers.
Industrial PRT thermometers fully comply with IEC 60751 industrial indexing standards, featuring the strongest compatibility, suitable for PLC, transmitters, paperless recorders and other industrial control equipment.
2. Difference in Packaging Structure
SPRT: Stress- free platinum wire winding + long quartz sleeve, cannot be bent or subjected to strong vibration, only used in fixed installation inside laboratory constant temperature baths.
Reference PRT: Compact thin sleeve, allows slight bending and plug-and-play portable installation, compatible with various temperature calibration equipment.
Industrial PT100: Pressure-resistant, shock-proof and waterproof sealed structure, supports threaded and flange installation, applicable to humid, corrosive, vibrating industrial sites.
3. Recommended Calibration Cycle
SPRT: Annual verification by national metrology institute is mandatory.
Reference PRT: Annual calibration by 3rd party lab.
Industrial PT100: Annual calibration is recommended for key metrological working conditions.