Traceable Long-Stem Digital Thermometer Model 90225-15

Overview

The Traceable Long-Stem Digital Thermometer Model 90225-15 is a precision-engineered handheld temperature measurement instrument designed for reliable, real-time thermal monitoring in demanding laboratory, quality control, and industrial environments. Utilizing a high-stability NTC thermistor sensor embedded within a corrosion-resistant stainless steel probe, this thermometer delivers rapid thermal response and consistent repeatability across its full operating range of –50°C to 150°C. Its long-stem configuration—featuring an 8-inch (203 mm) immersion depth and 11-inch (280 mm) overall length—enables accurate in-process temperature acquisition during active mixing, incubation, sterilization, or thermal validation without disturbing sample integrity. The device operates on a single replaceable battery and incorporates an on/off switch to extend operational life, making it suitable for extended use in ovens, incubators, water baths, fermentation vessels, and deep-well containers.

Key Features

• Stainless steel probe (3.5 mm diameter) with broad chemical resistance—compatible with aqueous solutions, organic solvents, food matrices, and semi-solid media
• High-contrast LCD display with 6.35 mm digit height for clear readability under varied lighting conditions
• Real-time update rate of 1 reading per second, ensuring dynamic thermal tracking during exothermic/endothermic processes
• Switchable °C/°F units with default factory setting in °C for compliance with international scientific reporting standards
• Lightweight construction (<28 g) minimizes operator fatigue during prolonged handling or repetitive measurements
• Included NIST-traceable Certificate of Calibration (per ISO/IEC 17025) documenting as-tested accuracy at multiple points across the range
• Compliant with ISO 9001 quality management requirements and ANSI/NCSL Z540-1 metrological traceability standards

Sample Compatibility & Compliance

This thermometer is validated for direct contact measurement in diverse physical states—including liquids (water baths, reagent solutions, culture media), gases (oven and incubator ambient air), semi-solids (agar plates, gels, pastes), and solid surfaces (heating blocks, sterilization trays). Its probe geometry allows stable insertion into narrow-necked glassware such as test tubes, Erlenmeyer flasks, and volumetric cylinders while maintaining mechanical stability during magnetic or mechanical stirring. The device meets general-purpose requirements for GLP-compliant temperature verification and supports routine equipment qualification (IQ/OQ) in regulated environments. While not inherently 21 CFR Part 11 compliant (as it lacks electronic audit trail functionality), its calibration certificate satisfies documentation requirements for FDA-regulated labs performing non-critical thermal checks under GMP-aligned procedures.

Software & Data Management

The Traceable Model 90225-15 operates as a standalone analog-to-digital conversion system with no onboard memory, wireless interface, or software dependency. All readings are displayed locally in real time; no data logging, export, or PC connectivity is provided. This architecture ensures electromagnetic compatibility (EMC) in high-interference settings (e.g., near centrifuges or RF heaters) and eliminates firmware-related failure modes. For laboratories requiring documented temperature records, users may manually transcribe values into LIMS or ELN systems—or pair the instrument with external digital loggers certified for concurrent use. The included Traceable Certificate provides full metrological traceability to NIST via an A2LA-accredited calibration laboratory, including uncertainty budgets and environmental test conditions (23 ±2°C, 45–55% RH).

Applications

• Verification of thermal setpoints in CO₂ incubators, forced-air ovens, and refrigerated storage units
• In-process temperature monitoring during enzymatic reactions, PCR setup, or cell culture maintenance
• Calibration cross-checking of fixed-point reference baths and dry-block calibrators
• Food safety testing: core temperature validation in cooked meats, dairy products, and ready-to-eat meals
• Environmental chamber mapping and uniformity studies per ISO 17025 Clause 6.4.3
• Validation of sterilization cycles (e.g., autoclave belt monitoring, hot-air oven dwell verification)
• Educational labs requiring rugged, student-safe instrumentation with unambiguous readouts

FAQ

Is this thermometer suitable for measuring temperatures inside sealed pressure vessels or autoclaves?
No. The probe is not rated for overpressure or steam exposure beyond standard atmospheric conditions. It is intended for open-vessel or ambient-chamber use only.

Does the Traceable Certificate satisfy FDA 21 CFR Part 11 requirements?
No. As a manual-read instrument without electronic signature, audit trail, or data retention capability, it does not meet Part 11 criteria. However, the certificate supports ALCOA+ principles when manually recorded with controlled documentation practices.

Can the probe be immersed fully in liquid without damage?
Yes—the entire stainless steel stem is hermetically sealed and rated for continuous immersion in non-corrosive aqueous and polar organic media. Avoid prolonged exposure to strong oxidizers (e.g., concentrated HNO₃) or halogenated solvents.

What is the typical battery life under normal usage?
With the power switch enabled only during active measurement, battery life exceeds 1,000 hours. The unit automatically powers down after 10 minutes of inactivity to conserve energy.

Is recalibration required before each use?
No. Per ISO/IEC 17025, routine recalibration is determined by usage frequency, criticality of application, and observed drift. Most laboratories perform annual verification or after any physical shock or thermal overload event.