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Page 116 Stuart® Catalogue
Water Purification
Introduction
Distillation is a natural process that has been used to purify liquids
for many hundreds of years. Today it remains the most commonly
used technique for water purification in laboratories. From schools to
research institutes the simplicity, reliability and versatility of distillation
make it the first choice for producing pure water for general use. It has
the widest capability of any method of water treatment and is ideal for
the removal of:
• Dissolved inorganic salts
• Bacteria
• Pyrogens
• Particulate matter
• Colloids
• Organic material boiling at >100°C
The performance of a Water Still is less dependant on the quality and
temperature of the feed water than most other methods of water
treatment. It is a visible process, easy to monitor and has no hidden
resins or membranes to degrade and affect water quality.
Principles of distillation
There is a major difference between distillation and all other techniques
of water purification in that the contaminants are not removed from
the water but that the water is removed from its contaminants.
The feed water is boiled producing pure steam with contaminants
being left behind in the boiling chamber. Steam is then condensed back
into pure water. It is this double phase change which gives distillation
its versatility and reliability. The only contaminants which can carry
through the phase change are organic materials with a boiling point
below 100°C and dissolved gases.
How a Stuart® Water Still works
There are 4 basic components to any Stuart® Water Still:
• Boiler
• Condenser
• Constant level device
• Heater
Water is heated in the boiler to produce pure steam. This is fed into
the condenser via a long vertical tube with baffles in order to prevent
carry over of raw water droplets. Water is fed through the condenser,
cooling the steam to produce distilled water and itself being warmed
in the process. This warmed water is then fed to the boiler via the
constant level device which maintains the water in the boiler at the
correct level and increases efficiency. The vertical design of condenser
is common to all Stuart® Water Stills and ensures the maximum energy
transfer between cooling water and condensate. These highly efficient
condensers produce cold distilled water ready for immediate use.
Stuart® Catalogue