What are the uses of distilled water in industries?

What are the uses of distilled water in industries?

Distilled water has had most dissolved minerals removed, so it is chosen when those minerals would corrode metal, leave limescale or disturb a result. A chemical supplier lists these main uses.

• Laboratories: most lab work needs distilled or double-distilled water, because in assays any impurities would affect the results.
• Medical equipment: the supplier mentions CPAP humidifiers, where distilled water can be part of the process.
• Lead-acid batteries: topping up. The supplier warns that no minerals should be added, as they can be corrosive and shorten battery life.
• Cooling systems: minerals in tap water can corrode a car engine and use up anti-corrosion additives in antifreeze.
• Steam irons: older models tend to work better with distilled water, although newer models may not need it.

Can you always use distilled water in an autoclave?

No. A guide comparing manufacturers shows they disagree. One maker says to use only steam-process distilled water with under 5 ppm total dissolved solids. Another recommends distilled and allows deionized. A UK laboratory maker says distilled or ultra-pure water is unsuitable unless the unit has been adapted, because extremely pure water can corrode copper pipework and brass valves and can defeat conductivity-based water level and heater controls. The rule is to use the water your own model’s manual names.

When is distilled water not suitable?

• Aquariums: completely pure water cannot sustain fish for long without added nutrients and additives.
• Equipment that needs some minerals: as with the lab autoclave above.
• Drinking as your only water: not an industrial point, but it lacks minerals; ordinary safe tap water is fine.

Distilled vs deionized water

They are not interchangeable in every machine. Check the specification and ask the manufacturer.

Safety

Check the product label and safety data sheet for any chemical, and consult your safety adviser if unsure.