Water Filters

What you can't see can harm you - water that looks clean may not be

Water FiltersClean water may be a natural prerequisite of occupational health, but it isn't always straightforward.

Every building in North America has running water, and almost every industrial process involves water for diluting, mixing, humidifying, dehumidifying, heating, cooling, drinking and other purposes.

The second most common mechanical device on the planet is the pump (second only to the electric motor.) And the most common pump application is for the treatment and movement of water. As a result, water filtration should be as important as air filtration; untreated/unfiltered water gets quite nasty quite quickly. People tend to notice dirty air since smog is visible; however, dirty water can look clean and actually be unhealthy.

"Dirty" is a relative term; you need to ascertain just how dirty the water is, where it came from, its degree of harmfulness, and how you can stop the contamination and/or clean it up?

Dirt is measured in microns, a metric term for one-millionth of a meter. Sounds small, but don't let that fool you. It does not take long for these tiny items to make a difference.

A water filtration system may not seem, at first glance, to fall into the category of safety equipment. But water purification is often required to minimize contamination.

A typical water filter could be rated as 10 micron. This implies that anything larger than 10 microns will not get through, but that's not necessarily true as dirt is not uniform in shape.

Various sources of dirty water include

  • mechanical devices such as pumps, valves and controls with moving parts; tiny pieces of these devices are continuously being scraped away during operations
  • maintenance workers that stir things up as they replace worn mechanical parts
  • a contaminated source of water
  • leaks within the system that allow for an influx of particulate.

How do you filter out the dirt?

This step can be a bit confusing and possibly expensive. Typical industrial filtration consists of a housing that accommodates an element, bag or filter bed. Beds range in size from a few feet wide by a few feet long to as much as six feet wide by 12 feet long.

The element would be ten inches long by three inches diameter, ranging from one micron up to 200 microns. (Other micron ratings are available, but one to 200 is quite typical.) Elements come in various materials for different applications.

That same housing could also use a bag. Bags hold more particulate but have much fewer square inches of filter surface. Elements have a small amount of space to hold dirt but have dramatically more surface area. For very large applications with extremely dirty water, a filter press will be required.

Some other possible water purification methods include

  • distillation
  • reverse osmosis which uses force to push water through a membrane
  • magnets
  • infra-red light to sterilize microbes
  • softeners are designed to soften the water, but they also filter to a degree
  • sand filters similar to the ones used in your pool.
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