Isotech 915 Parallel Tube Stirred Liquid Bath

The Isotech 915 Parallel Tube Stirred Liquid Bath is a high‑performance calibration bath designed for laboratories that require the lowest possible uncertainties in temperature measurement. Engineered for primary and secondary metrology, the 915 provides an exceptionally stable and uniform temperature environment thanks to its unique parallel tube architecture.

With deep immersion, excellent uniformity and a large working volume, the 915 is ideal for calibrating SPRTs, PRTs, thermocouples and liquid‑in‑glass thermometers.

Parallel Tube Design — superior uniformity

Unlike conventional stirred baths, the 915 uses a parallel tube flow system that guides the fluid in a controlled loop: upward in the rear chamber and downward through the calibration zone. This minimizes vertical and axial gradients, creating a highly isothermal environment essential for comparison calibrations with very low uncertainties.

Deep immersion and large working volume

The 915 offers a generous calibration chamber, typically 100 mm in diameter and up to 530 mm deep (depending on configuration). This allows full immersion of long thermometers, including:

• > long liquid‑in‑glass thermometers
• > extended‑length SPRTs
• > ITS‑90 fixed‑point cells (with optional holders)

The immersion depth exceeds the recommendations of the Supplementary Information to the ITS‑90.

Outstanding thermal performance

The 915 delivers exceptional thermal characteristics:

• > Absolute stability in the millikelvin range
• > Vertical uniformity better than 1 mK
• > Axial uniformity optimized by the parallel tube flow

These features make the 915 suitable for demanding metrological applications, including international comparisons.

Efficient fluid usage

Despite its deep immersion capability, the 915 requires a relatively modest fluid volume, reducing the cost of specialty oils or alcohols. The bath heats and cools efficiently and maintains long‑term stability with minimal intervention.

Ease of use and versatility

Designed for routine laboratory operation, the 915 includes:

• > intuitive controls
• > fast drainage
• > over‑temperature protection
• > compatibility with equalising blocks, LIG supports and ITS‑90 fixed‑point cell baskets
• > optional monocular for precise LIG thermometer reading

This flexibility allows the 915 to support a wide range of calibration tasks. The Isotech 915 Parallel Tube Stirred Liquid Bath combines deep immersion, excellent uniformity and outstanding stability in a robust and versatile design. Its parallel tube architecture and large working volume make it an ideal choice for laboratories seeking the lowest uncertainties in temperature metrology.