Ted Pella 28156-230 Tissue Floatation Water Bath

Overview

The Ted Pella 28156-230 Tissue Floatation Water Bath is a purpose-engineered thermal platform designed specifically for histology laboratories performing tissue section flotation prior to microscope slide mounting. It operates on the principle of controlled conductive and convective heat transfer within a precisely regulated aqueous medium, enabling consistent surface tension reduction and optimal tissue ribbon expansion during the water bath step of paraffin sectioning workflows. Unlike general-purpose heating baths, this unit integrates optical and ergonomic features—such as side-illuminated black-background glass basin and low-profile modular architecture—to support visual verification of tissue integrity, orientation, and unfolding without distortion or glare. Its microprocessor-based temperature regulation ensures stable thermal conditions across the full 5 L working volume, critical for reproducible section adhesion and avoidance of curling or folding artifacts.

Key Features

• Removable rectangular borosilicate glass basin with black matte interior finish for high-contrast tissue visualization
• Integrated side-mounted LED illumination system with dedicated ON/OFF control—designed to eliminate specular reflection while enhancing edge definition of delicate tissue ribbons
• Stainless steel corrosion-resistant temperature probe with flip-down mechanical actuation; automatically disables heating when lifted and re-engages upon repositioning into the bath
• Dual LED display showing real-time actual temperature and user-setpoint simultaneously, with push-button digital adjustment in 0.1 °C increments
• Low-profile chassis (11.4 cm height) optimized for benchtop integration beneath microtomes and automated slide stainers
• Internal recirculation pump ensures uniform thermal distribution without external tubing or risk of contamination from external loops

Sample Compatibility & Compliance

The 28156-230 accommodates standard histological tissue ribbons (typically 3–5 µm thick, up to 8 cm wide), including those cut from paraffin-embedded specimens, frozen sections, and some resin-embedded samples. Its 5 L capacity supports simultaneous flotation of multiple ribbons without significant thermal lag. The unit complies with IEC 61010-1:2010 for electrical safety in laboratory equipment and meets UL 61010-1 certification requirements for North American markets. While not classified as a medical device, its design aligns with GLP documentation practices—temperature setpoints, actual readings, and operational status are directly observable and manually recordable for audit trails. No integrated data logging or FDA 21 CFR Part 11 compliance is provided; users requiring electronic audit trails must integrate external validation-grade data loggers.

Software & Data Management

This instrument operates as a standalone analog-digital hybrid system with no embedded firmware-based software, network interface, or cloud connectivity. All controls—including temperature setting, LED activation, and power cycling—are executed via physical push buttons and mechanical switches. Temperature data remains local to the dual LED display and is not exportable or programmable. For laboratories implementing digital quality management systems (QMS), manual entry of setpoint and observed temperature into LIMS or electronic lab notebooks (ELN) is required per SOP. Calibration verification should be performed using an NIST-traceable reference thermometer at least daily prior to use, in accordance with CAP and CLIA pre-analytical standards for histopathology.

Applications

• Flotation and stretching of paraffin-embedded tissue ribbons prior to adhesive slide mounting
• Controlled warming of cryosections to minimize ice crystal artifact formation during thaw-mounting
• Pre-heating of specialty mounting media (e.g., gelatin-coated slides, charged glass) to enhance tissue adherence
• Supporting automated tissue processors and slide stainers where precise bath temperature synchronization is required
• Use in research settings involving hydrogel-based tissue clearing protocols requiring stable sub-75 °C aqueous incubation

FAQ

Is the 28156-230 suitable for use with flammable solvents or oil-based media?

No. This unit is rated exclusively for aqueous operation. The glass basin, LED housing, and internal electronics are not designed for immersion in or exposure to organic solvents, mineral oil, or silicone fluids.
Can the temperature probe be calibrated in-house?

Yes—the stainless steel probe is field-replaceable and compatible with standard dry-block or liquid-bath calibration sources. Ted Pella recommends annual verification against a certified reference thermometer per ISO/IEC 17025 guidelines.
Does the unit include a drain valve or overflow protection?

No. The basin has no built-in drainage port or level-sensing mechanism. Users must manually monitor fill volume to maintain immersion depth of the probe tip and avoid dry-heating conditions.
What maintenance is required beyond routine cleaning?

Weekly descaling with diluted acetic acid solution is recommended if using tap water. Deionized or distilled water significantly extends service intervals and prevents mineral deposition on the heater element and probe surface.