Cole-Parmer WS-200A-4 Stuart Water Still, 4 L/h

The WS-200A-4, formerly the Stuart A4000, is a cabinet-style water still that produces 4 L per hour of single-distilled water. Borosilicate glassware and silica-sheathed heaters inside a protective cabinet remove organics, bacteria and pyrogens from virtually any raw water supply, and the unit can be converted to pretreated feed.

The condenser keeps distillate droplets in contact with the cooling coil for longer, giving efficient heat transfer and cold distilled water straight away. The all-glass construction can be descaled quickly with strong mineral acids without dismantling, and a large-bore stopcock with PTFE key drains cleaning chemicals.

A reservoir level sensor switches off the heaters and cooling water when the storage reservoir is full and restarts the still when the level drops. Flow sensor, overtemperature thermostat, acrylic screen and lid allow unattended operation, and the still can be wall-mounted to save bench space.