Do water filters really work
I have seen a lot of water filters and water dispensers which do not use any electric power. However my question is Do they actually purify water or is it some bogus stuff. I see just a filter inside. How can it purify the water is my question. Do people buy simply for the sake of it, or because it purifies water.
Last edited by Andy CWS; 10-08-2011 at 04:00 AM.
One post, edited by Andy... spammer-link? Whatever.
> a lot of water filters and water dispensers which do not use any electric power
There sure are "a lot" of types of filters. From screens to block "frogs and logs" to filters which remove virus and dissolved minerals.
Most filter types do not need electric power.
> Do they actually purify water
Run muddy lake-water through a handkerchief: it comes through less muddy. No electricity. Yes, most people would not call that "Purify". Utterly-pure water is quite difficult, expensive, and usually not needed. We usually accept water which has nearly-no germs, insignificant toxic chemicals, little smell, does not stain the sink. These goals can usually be met "without electricity".
Many complete water-systems "need power", mostly to make the water move and spurt. Ground water in a well must be lifted 100'-1000' to the surface, then an equivalent 100' to have customary pressure at the taps. This is very much more work than forcing water through most filters. Of course in most cases, electric-power pumps are more convenient than hand-pumps or engine-powered pumps.
Most filters cause some pressure-loss. But a reasonable size filter often causes very slight pressure loss. I have about 40psi from my pump, and 39psi-35psi after the filter.... the slight difference is the resistance of the filter paper against the amount of water I am drawing.
There are other types. Some types need to be "back-washed" to float the crud off and restore full flow. This can be manual, but automatic back-wash is more convenient, and electricity is usually the most convenient way to work the timer and valves. Some super-fine filters are so restrictive that they would have to be unreasonably big to avoid large pressure loss; where electricity is available it may be more economic to use a small filter with a booster pump. There are probably electrostatic filters. And distilled water can use electric boilers. I have a "UV light filter" which uses electricity to power a special lamp which kills germs. This electric part actually is not a "filter"... the germs come through but dead and harmless. This particular unit follows the germ-lamp with a stage of paper and a stage of fine carbon to filter the dead germs and also chlorine and ozone.
There are many different types of filters for many applications. Your question seems to be more in reference to Drinking water filters.
Many common "pitcher filters" actually do a pretty good job of filtering the water and improving the quality. All pitcher filters have either activated carbon or a carbon block filter which can remove chlorine and many VOC's. Some of these filters along with carbon have DI media to reduce the TDS (total dissolved solids) and will substantially improve the quality of the water in very limited quantities.
In-line or POU (point of use) filters are dependent on the pressure drop across the filter to remove particulates and other contaminants. In the case of Reverse Osmosis the greater the pressure drop the better the water quality produced and contaminants removed. Most people do buy filter systems believing they do more than what it's designed for. In short it depends on what quality of water you want and the filtering system to make it.
> All pitcher filters have either activated carbon or a carbon block filter
There is a very old line of "ceramic" filters. Ceramic can be mixed and fired water-tight, or highly porous, or anywhere in between. The standard product flows very slowly but removes very-very fine particles. It clogs, but can be cleaned with a toothbrush.
This type won't remove chlorine (except what goes-off in the hour or so it takes to drip-through). It will reduce germs, but not reliably 99.999..% as required for marketing claims. It does take out all visible dirt.
No electricity. (Not for filtering: some deluxe models have night-lights and lift-pumps so you don't have to hold your glass below counter level in the dark.)
I believe that filters that use electric power are far better than the ones that they don't use. However, we should use different filters according to the situation. I like camping for example and I take a filter bottle which does the job for this situation. Every filter is for different situations. online pokies
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