Yiheng HWS Series Water Bath Circulator (Heating-Only)

Overview

The Yiheng HWS Series Water Bath Circulator (Heating-Only) is a precision-engineered static temperature control platform designed for consistent thermal conditioning of samples in research, quality control, and teaching laboratories. Unlike circulating baths, the HWS series operates as a non-circulating, gravity-convection water bath—ideal for applications where gentle, uniform heating without mechanical agitation is required. Its core function relies on resistive heating elements immersed beneath a stainless steel (304) bath chamber, coupled with a microprocessor-driven PID temperature controller that maintains setpoint stability within ±0.3°C across the full operating range (ambient +5°C to 99°C). The absence of a pump eliminates vibration transfer and fluid shear, making it suitable for enzymatic assays, cell culture pre-warming, solvent dissolution, and calibration standard equilibration where mechanical disturbance must be avoided.

Key Features

• Stainless steel (304) interior tank with seamless construction ensures long-term corrosion resistance and ease of cleaning—critical for repeated use with aqueous buffers, saline solutions, or mild organic solvents.
• One-piece molded ABS outer housing provides chemical resistance against common laboratory acids, bases, and alcohols while maintaining structural rigidity and ergonomic aesthetics.
• High-resolution LED display and intuitive 5-key interface enable precise setpoint entry, real-time temperature monitoring, and status feedback—including active alarm indicators.
• Dry-run protection is implemented via a dedicated thermal cutoff sensor positioned below the minimum fill level; activation requires manual reset to prevent unintended re-energization—a design aligned with IEC 61010-1 safety principles for Class II laboratory equipment.
• Optional independent over-temperature limiter offers redundant safety: a mechanically isolated bimetal switch interrupts power independently of the main controller, satisfying risk-mitigation requirements in GMP and GLP workflows.
• Adjustable well inserts allow flexible accommodation of various vessel diameters (e.g., test tubes, beakers, flasks), supporting multi-vessel parallel processing without cross-contamination.

Sample Compatibility & Compliance

The HWS series supports glass, polypropylene, and borosilicate containers up to 200 mm in height and 100 mm in diameter per well. Its static bath architecture avoids turbulence-induced sample degradation—making it compatible with temperature-sensitive biological reagents, polymer solutions, and reference standards requiring thermal homogeneity over time. Units are assembled and tested in accordance with ISO 9001-certified manufacturing protocols. While not certified to UL/CSA standards out-of-the-box, the design incorporates insulation, grounding continuity, and double-insulated heater wiring compliant with Clause 6.3 and Annex C of IEC 61010-1:2010. Documentation packages include factory calibration reports traceable to NIM (National Institute of Metrology, China) standards.

Software & Data Management

The HWS series operates as a standalone analog-digital hybrid instrument with no embedded data logging or PC connectivity. All operational parameters—including setpoint, real-time bath temperature, and alarm status—are displayed locally. For laboratories requiring audit trails, external USB or RS-232 data loggers (e.g., Omega OM-DAQPRO-5300) may be interfaced via optional analog voltage output (0–5 V DC proportional to temperature). The unit’s thermal stability profile (±0.2°C deviation over 2 hours at 37°C, per internal validation protocol) supports compliance with USP for “Thermal Stability of Aqueous Solutions” and ASTM E2251-22 Annex A1 for liquid bath uniformity assessment.

Applications

• Routine incubation of serum, media, or reagent stocks prior to assay execution
• Controlled dissolution testing of pharmaceutical tablets per USP
• Pre-heating of viscosity standards before rotational rheometry calibration
• Equilibration of pH electrodes and conductivity probes
• Enzyme kinetic studies requiring stable sub-physiological temperatures (e.g., 25°C, 30°C)
• Supporting ASTM D92 (Cleveland Open Cup) flash point testing when used as an oil bath configuration (with appropriate silicone or mineral oil)

FAQ

Does the HWS series support external temperature probe input for chamber monitoring?
No—the built-in Pt100 sensor is fixed and non-removable; external probe integration is not supported.
Can this unit be used with silicone oil for temperatures above 80°C?
Yes, provided the selected oil has a flash point >120°C and viscosity ≤100 cSt at operating temperature; users must verify compatibility with ABS housing at extended exposure.
Is the dry-run protection automatically reset after cooling?
No—manual reset via front-panel key sequence is required, in alignment with functional safety best practices for lab heating devices.
What is the typical temperature uniformity across the bath volume at 60°C?
Measured uniformity is ≤±0.4°C (max deviation) within the central 70% volume zone, verified using 9-point NIST-traceable probe mapping.
Are replacement well inserts available as spare parts?
Yes—standard inserts (Φ35 mm, Φ50 mm, Φ70 mm) and custom-machined options are available under part numbers HWS-INSERT-XX, subject to minimum order quantity.