Tanaka KV-5S Kinematic Viscosity Constant-Temperature Bath

Overview

The Tanaka KV-5S Kinematic Viscosity Constant-Temperature Bath is a precision-engineered thermal platform designed exclusively for standardized kinematic viscosity measurements of petroleum products—including base oils, lubricants, fuels, and bituminous materials—according to internationally recognized test methods. It operates on the principle of maintaining a thermally stable, homogeneous liquid bath medium (typically silicone oil or water, depending on temperature range) to ensure consistent thermal equilibration of capillary viscometers during efflux time measurement. The bath’s core function is to eliminate thermal drift and spatial temperature gradients that directly impact the accuracy and repeatability of kinematic viscosity calculations (ν = t × C, where ν is kinematic viscosity in mm²/s, t is efflux time in seconds, and C is the viscometer constant). Its integrated circular borosilicate glass cylinder (Ø300 × H330 mm) provides optical clarity and chemical resistance, while its four independent test ports enable parallel analysis or method validation across multiple capillary types—critical for laboratories performing ASTM D445, ISO 3104, IP 71, and GB/T 265 compliance testing.

Key Features

• High-stability temperature control with ±0.01 °C accuracy over extended durations (≥8 hours), achieved via Pt100 platinum resistance thermometer feedback and digital PID regulation through solid-state relays
• Five factory-preset temperature points (20, 40, 50, 80, 100 °C) with intuitive front-panel selection; optional custom calibration across 5–135 °C at 5 °C intervals for specialized applications such as high-temperature asphalt or synthetic ester evaluation
• Borosilicate glass bath vessel engineered for thermal inertia, mechanical robustness, and UV-stable transparency—enabling real-time visual monitoring of capillary flow without parallax error
• Rear-mounted fluorescent illumination system providing uniform side-backlighting for unobstructed observation of meniscus movement and efflux termination in suspended-level viscometers
• Modular holder architecture: accommodates Ubbelohde, Cannon-Fenske, and micro-Ostwald viscometers via interchangeable stainless-steel holders (4 supplied standard); compatible with ASTM D445-compliant capillary geometries including 0.4–1.2 mm bore diameters
• Dual thermal management: 1.5 kW immersion heater for rapid ramp-up; optional 600 W Peltier-based active cooling module (separately mounted) for sub-ambient stabilization or accelerated cooldown between test cycles

Sample Compatibility & Compliance

The KV-5S is validated for use with all gravity-driven capillary viscometers specified in ISO 3104 (petroleum products), ASTM D445 (standard test method for kinematic viscosity), IP 71 (Institute of Petroleum), and GB/T 265 (Chinese national standard). It supports both transparent and opaque samples—provided appropriate viscometer type and bath fluid are selected (e.g., silicone oil for >60 °C operation). The bath meets mechanical and thermal requirements outlined in ASTM D445 Annex A1 for constant-temperature bath performance verification, including axial and radial temperature uniformity testing per ISO 17025-accredited protocols. While the instrument itself is not certified to GLP or FDA 21 CFR Part 11, its stable thermal output, traceable Pt100 sensor, and digital setpoint logging capability support audit-ready documentation when integrated into laboratory quality systems compliant with ISO/IEC 17025:2017.

Software & Data Management

The KV-5S operates as a standalone hardware platform with no embedded firmware or proprietary software. Temperature setpoints, real-time bath readings (0.01 °C resolution), and manual offset corrections are managed exclusively via its front-panel digital display and tactile keypad. For laboratories requiring electronic data capture, the unit features a 0–5 V analog output signal (user-configurable for temperature) compatible with third-party DAQ systems, LIMS interfaces, or programmable logic controllers (PLCs). This analog interface enables time-synchronized logging of bath temperature alongside efflux timers or vision-based meniscus detection systems—facilitating full traceability under GLP or internal QA procedures. No cloud connectivity, remote access, or password-protected user roles are implemented, preserving deterministic behavior required in regulated environments.

Applications

• Routine QC testing of engine oils, hydraulic fluids, and transformer oils per ASTM D445 and ISO 3104
• Research-grade viscosity profiling of bio-based lubricants across wide temperature ranges (e.g., 5–100 °C)
• Bitumen and cutback asphalt characterization per ASTM D2170 and JIS K 2283, using calibrated vacuum-capillary assemblies
• Method transfer validation between laboratories requiring identical thermal boundary conditions
• Educational demonstrations of Newtonian fluid behavior and temperature-dependent viscosity relationships (Arrhenius and Walther equations)
• Calibration support for secondary reference viscometers in metrology labs accredited to ISO/IEC 17025

FAQ

What capillary viscometers are compatible with the KV-5S?
The bath accepts all gravity-flow capillary viscometers conforming to ASTM D445 geometry specifications—including Ubbelohde, Cannon-Fenske Routine, and micro-Ostwald types—via mechanically adjustable stainless-steel holders. Users specify viscometer type at order; holders are field-replaceable.
Is the Peltier cooler included by default?
No. The 600 W Peltier cooling module is an optional accessory, shipped separately with dedicated mounting hardware and power supply. It is required for operation below ambient or for rapid thermal cycling.
Can the temperature setpoint be adjusted in increments finer than 1 °C?
Yes. While preset points are fixed, manual temperature offset correction is adjustable in 0.01 °C steps via front-panel controls to compensate for system-specific thermal lag or sensor drift.
Does the KV-5S meet ISO/IEC 17025 requirements for accredited testing?
The instrument provides the thermal stability and measurement traceability necessary to support ISO/IEC 17025 compliance when used within a documented quality system—including regular verification using NIST-traceable thermometers and bath uniformity mapping per ISO 17025 Clause 6.4.2.
What maintenance is required for long-term accuracy?
Annual verification of Pt100 sensor calibration against a reference thermometer and periodic cleaning of the glass bath interior with non-abrasive solvents are recommended. The solid-state relay and heating element have no scheduled replacement interval under normal operating conditions.