Chengyi HSS-1 Precision Constant-Temperature Circulating Bath

Overview

The Chengyi HSS-1 Precision Constant-Temperature Circulating Bath is an engineered thermal management system designed for laboratory applications requiring stable, uniform, and controllable temperature environments. Based on resistive heating and PID-controlled feedback regulation, the HSS-1 maintains precise thermal setpoints across its operational range of 10 °C to 100 °C — with a typical stability of ±0.03 °C under steady-state conditions. Its 7-liter stainless-steel bath chamber supports both internal circulation (for direct sample immersion) and external recirculation (via integrated pump and dual-port fittings), enabling integration with external equipment such as viscometers, spectrophotometer cells, or reaction jackets. The unit operates on standard 220 V AC, 50–60 Hz power and features a 1 kW heating element optimized for rapid thermal recovery following load changes. Unlike refrigerated circulators, the HSS-1 is configured exclusively for heating applications — making it ideal for protocols where sub-ambient temperatures are not required, yet high thermal fidelity and low-noise operation are critical.

Key Features

• High-stability temperature control: ±0.03 °C stability at setpoint, achieved via digital PID algorithm with adaptive tuning and real-time sensor compensation
• Dual-mode fluid circulation: Integrated centrifugal pump delivers up to 6 L/min flow rate, supporting both internal bath homogenization and external loop connectivity (e.g., jacketed reactors or calorimeters)
• Robust stainless-steel bath tank: Dimensions 350 × 160 × 320 mm (L × W × H); open-top aperture 202 × 162 mm for unobstructed sample access and probe insertion
• Low-acoustic operation: Optimized pump mounting and thermal insulation reduce operational noise to <45 dB(A) at 1 m distance — suitable for shared lab environments and QC laboratories
• Intuitive digital interface: LED display with keypad control for temperature setpoint, real-time bath reading, and status indicators (heating active, error code, pump status)
• Over-temperature and dry-run protection: Embedded safety cutoffs prevent heater activation when fluid level falls below minimum threshold or when sensor fault is detected

Sample Compatibility & Compliance

The HSS-1 accommodates a wide range of sample vessels including glass beakers (up to 1 L), cylindrical reaction tubes, cuvettes, and custom jacked fixtures. Its open-bath geometry allows simultaneous use of multiple probes (e.g., PT100 sensors, pH electrodes, or conductivity cells) without interference. While not certified to ISO/IEC 17025 calibration standards out-of-box, the unit meets general-purpose laboratory requirements aligned with ASTM E2877-22 (Standard Guide for Calibration of Liquid-in-Glass Thermometers) and supports traceable calibration using NIST-traceable reference thermometers. Its construction complies with IEC 61010-1:2010 for electrical safety in laboratory equipment. No refrigerant or hazardous fluids are used; operation is limited to water, silicone oil, or other non-corrosive heat-transfer media compatible with stainless steel and EPDM seals.

Software & Data Management

The HSS-1 operates as a standalone analog/digital hybrid instrument without native USB or Ethernet connectivity. However, its analog output (0–5 V or 4–20 mA, configurable) enables integration into centralized LabVantage, DeltaV, or Siemens Desigo SCADA systems for remote monitoring and alarm logging. For GLP/GMP-regulated workflows, users may connect an external data logger compliant with FDA 21 CFR Part 11 (e.g., Omega OM-DAQPRO-5300) to record time-stamped temperature traces with electronic signature support. All manual setpoints and operational logs remain locally stored in non-volatile memory for audit trail reconstruction during internal quality reviews.

Applications

• Calibration of temperature-sensitive analytical instruments (e.g., densitometers, refractometers, and thermal conductivity analyzers)
• Stabilization of optical components in spectroscopy setups requiring thermal drift suppression
• Controlled-temperature incubation of biological reagents prior to ELISA or PCR preparation
• Viscosity measurement support for rotational rheometers and capillary viscometers
• Accelerated stability testing of pharmaceutical formulations per ICH Q1A(R2) guidelines (when paired with validated environmental chambers)
• Material testing per ASTM D2196 (Brookfield viscosity) and ISO 2555 (solution viscosity), where bath temperature must remain within ±0.1 °C tolerance

FAQ

Does the HSS-1 support cooling or refrigeration?
No — the HSS-1 is a heating-only bath. It cannot achieve temperatures below ambient. For sub-zero operation, consider the HS-4 model (–15 °C to +95 °C), which integrates a compressor-based cooling system.
Can the HSS-1 be used with silicone oil or other heat-transfer fluids?
Yes — provided the fluid is chemically compatible with stainless steel (304 grade) and EPDM gaskets, and its flash point exceeds the maximum operating temperature (100 °C). Viscosity should remain below 500 cSt at 25 °C to ensure adequate pump performance.
Is external temperature probe input supported?
No — the HSS-1 regulates based solely on its internal Pt100 sensor. External probe feedback requires third-party PID controllers interfaced via analog input.
What maintenance is recommended for long-term reliability?
Monthly inspection of water level and cleanliness; annual descaling using 5% citric acid solution if used with hard water; biannual verification of temperature accuracy using a NIST-traceable thermometer.
Does the unit include a drain valve for fluid replacement?
Yes — a bottom-mounted brass drain valve with quick-release fitting facilitates complete fluid evacuation without tilting or disassembly.