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The BWS-20 Digital Water Bath is engineered for laboratory applications requiring precise, stable, and uniform temperature-controlled heating across a broad range — from ambient +5°C up to 100°C. Built around a PID temperature controller with a large LCD display, a built-in circulating pump for uniform heat distribution, and a stainless steel chamber for chemical resistance and durability, the BWS-20 delivers the temperature consistency and operational reliability demanded by biological, chemical, pharmaceutical, and microbiological laboratory workflows. With an adjustable timer range of 1 to 5999 minutes, independent over-temperature protection compliant with DIN 12880, and a convenient drain valve for straightforward maintenance, the BWS-20 is the precise, safe, and practical digital water bath for the modern research laboratory. Enquire about the BWS-20 today.
AvailableThe BWS-20 Digital Water Bath combines PID temperature control, a built-in circulating pump, stainless steel construction, and a comprehensive timer system to deliver uniform, precise heating across its 20L chamber — supporting a broad range of biological, chemical, and pharmaceutical laboratory applications with consistent, reproducible results.
The BWS-20 is controlled by a PID (Proportional–Integral–Derivative) temperature controller that continuously monitors chamber water temperature and adjusts heating output to maintain the setpoint with ±0.3°C fluctuation accuracy. Unlike simple on/off thermostat controllers, the PID algorithm anticipates temperature overshoot and undershoot, delivering faster setpoint recovery and more stable long-term temperature maintenance. The large LCD display provides clear, real-time visibility of both the actual and target temperature at the workbench — reducing operator error during temperature setting and monitoring across extended heating sessions.
The BWS-20 incorporates a flexible timer function with a range of 1 minute to 5999 minutes — equivalent to just under 100 hours of unattended timed operation. This extended timer range makes the BWS-20 suitable for both short-duration protocols such as enzyme reactions and quick sample thawing, and long-duration applications such as overnight incubation, extended hybridisation, and sustained microbiological culture heating — all within a single programmable setting. The preset ON/OFF function allows the timer to automatically activate or terminate a heating cycle at a pre-programmed time, supporting flexible laboratory scheduling.
A built-in circulating pump actively distributes heated water throughout the BWS-20's 20L stainless steel chamber, eliminating the temperature stratification that occurs in non-circulating water baths — where water near the heating element can be significantly warmer than water at the chamber surface. The circulating pump ensures that samples placed at any position in the BWS-20 — centre, edge, top, or bottom — experience the same ±0.3°C temperature conditions, a critical requirement for experiments where temperature uniformity directly affects the reproducibility and comparability of results.
The BWS-20 features a stainless steel inner chamber that resists corrosion from the range of chemicals, buffer solutions, and biological media that may enter the water bath during routine laboratory use. The stainless steel construction also withstands the repeated thermal cycling from ambient to 100°C without degradation — maintaining the structural integrity and surface cleanliness of the chamber over the full operational life of the unit. The no-angle inner chamber design eliminates internal corners and recesses where biological and chemical residues can accumulate, making thorough cleaning straightforward and time-efficient.
The BWS-20's inner chamber is designed without angled internal corners — a feature that significantly simplifies cleaning and decontamination between different sample types or experimental protocols. Conventional water bath chambers with sharp internal corners create areas where biological material, chemical residues, algae, and scale accumulate over time — requiring more intensive cleaning effort and increasing the risk of cross-contamination. The BWS-20's smooth, angle-free interior can be wiped clean completely with a single pass, reducing maintenance time and supporting laboratory hygiene standards.
A standard stainless steel bottom plate separates sample vessels from direct contact with the heating element on the base of the BWS-20 chamber. This design prevents sample vessels from resting directly on the heating element surface — where localised overheating could damage heat-sensitive samples, denature biological materials, or cause uneven heating on the base of glass or plastic tubes and flasks. The bottom plate distributes heat from the element evenly into the water volume, contributing to the uniform temperature distribution achieved in conjunction with the circulating pump.
The BWS-20 is fitted with a drain valve that allows complete water removal from the 20L chamber without the need to manually tip, siphon, or bale the chamber contents. The drain valve supports regular water changes — recommended to prevent algae growth, scale buildup, and bacterial colonisation of the water bath — and allows complete chamber drainage prior to deep cleaning, long-term storage, or relocation of the unit. In a 20L water bath, a functional drain valve represents a significant practical time saving compared to manual water removal methods.
The BWS-20 Digital Water Bath integrates five independent safety systems — covering over-temperature protection, power interruption management, current protection, and deviation monitoring — to ensure safe, unattended laboratory operation across extended heating sessions and overnight protocols.
The BWS-20's preset ON/OFF function allows operators to programme a specific activation and deactivation time for the heating cycle — enabling the water bath to begin heating automatically before the operator arrives in the laboratory, or to switch off automatically at the end of a timed protocol. This programmed control reduces the risk of samples being left at temperature for longer than the protocol requires — a common cause of sample degradation, evaporation, and chemical alteration in unattended water bath applications where manual switch-off is relied upon.
The BWS-20 incorporates power interruption protection that automatically restores the pre-interruption operating state — including setpoint temperature and timer remaining — when power supply is restored following an unplanned outage or mains interruption. Without this feature, a power interruption during an overnight or extended protocol would result in the water bath resuming at the default startup state, requiring operator reset and invalidating time-sensitive experimental results. The automatic restart function protects protocol integrity and sample viability during unattended long-duration heating cycles.
The BWS-20 features an independent over-temperature protection system that operates as a completely separate circuit from the primary PID temperature controller, fully compliant with DIN 12880 — the German Institute for Standardization's standard for laboratory heating equipment safety. If the primary PID controller fails or malfunctions and chamber temperature rises above the safe upper limit, the independent limiter cuts power to the heating element autonomously — preventing thermal damage to samples, glassware, and the chamber itself without requiring any operator action. DIN 12880 compliance provides documented assurance of the over-temperature protection system's reliability and performance standard.
The BWS-20 activates a temperature deviation alarm when the chamber temperature deviates beyond a defined threshold from the working setpoint — alerting the operator to a heating system malfunction, insufficient water level, or other condition preventing the PID controller from maintaining the target temperature. This alarm is particularly important during unattended long-duration heating protocols, where an undetected temperature deviation could compromise time-sensitive biological incubations, enzymatic reactions, or chemical heating processes before the operator's next scheduled check.
The BWS-20 incorporates over-current protection that automatically disconnects the heating circuit if current draw exceeds the safe operating limit — protecting the heating element, electrical components, and connected power supply from damage caused by electrical faults, wiring irregularities, or component failures. Over-current protection is a critical safety feature for a 1200W laboratory heating appliance operating on a shared laboratory electrical circuit, where unprotected over-current events could pose fire or electrical safety risks in the laboratory environment.