so if a water trap can equal or exceed a cyclone via misting, how is it — “in general” — a “no”? not picking at nits here, but your responses are rather confusing.
I’m sorry you have not understood. Let’s try this again.
okay… is a water trap more effective than a cyclone/vortex approach re dust collection?
A water trap’s efficiency depends on its design. A simple water trap will not exceed the efficiency of cyclone. A water trap that includes misting, agitation, and other complex issue that go into water trap design can equal or exceed the efficiency of a cyclone.
Few, if any, non commercial water trap users will be willing or able to design a water trap that meets or exceeds a cyclone for efficiency since the design and construction issues are complex.
Simple water traps are “pretty good” but do not exceed the efficiency of a cyclone.
Water traps are cool! A conversation piece for sure as they aren’t seem much today. Definitely simple to construct, cheaper than a cyclone (not counting ones time), and for a simple one pretty good.
Water traps were used before cyclones became popular. The simplicity of the cyclone coupled with not having to deal with water lead to them virtually disappearing from use. The “wet mess” is quite a challenge to deal with on a commercial scale - heavy and yucky.
The “wet mess” that comes out of a water trap is considered repulsive by some. YMMV.
A cyclone, water trap, Thien or other technology function as a “dust separator”, removing a large percentage of the “dust” before it enters a “dust collector” (vacuum). This reduces the stress/mess on the “dust collector” and, should it have a filter, extends the life of the filter (since far fewer particles get to it).
As I’ve written about elsewhere, a HEPA filter (rated at 0.3 micron) is necessary when the air exhausted from the “dust collector” is “inside” - where humans are. This is the only way to ensure that one is reaching safe levels of dust “inside”.
If the exhaust can be dumped “outside” and one can ensure that the air doesn’t easily return to the work area, no HEPA filter is necessary - but a “dust separator” is necessary. We don’t dump bulk dust outside - this is safety hazard. Dumping air outside has a downside that may prevent its use for some - noise. The tubing sends quite a bit of noise outside… perhaps upsetting a neighbor.
When dumping air “outside” - after going through a “dust separator” - one doesn’t need a HEPA filter but it’s a good idea to have a simple filter. A 5 micron cloth filter bag is an inexpensive and acceptable solution - they can be washed and reused! The minimal filter “outside” prevents “snow” from accumulating outside the exhaust port - because some particles of all sizes do get through and over time they settle around the exhaust port.
Cyclone “dust separators” are the industry recognized, well tested, and well understood method of “dust separating” on the small to medium scale. There are other technologies used on the industrial scale when dealing with massive amounts of dust… these are not applicable to us.
One alternative to the cyclone and water trap that is applicable is the Thien dust separator. The cyclone element is somewhat difficult for most people to build (difficult to construct shape; the parameters to be efficient are complex); the Thien is easy and inexpensive to build - and no water. The downside of a Thien is that it is generally not as efficient as a cyclone and commercial cyclones have become very accessible price wise - we see them being use less and less now-a-days.
A Thien and a water trap are going to approximately the same efficiency when properly designed - the Thien slightly better compared to simple water traps. Between the two - not having a cyclone - I would go with the Thien as no water and no “wet mess”. YMMV.
Since the “dust separator” is technically optional when the exhaust air is “inside” - the HEPA filter is the ultimate safety device for air quality - the efficiency of the “dust separator” is important (lower means the filters are “used up” faster) but not critical.
@imp had a discussion with me about using a water trap, including the design of what he was doing, and he understands the tradeoff he is making - low budget and not necessarily as efficient as a cyclone - but not, by any means, a bad thing to do. Anything (“dust separator wise”) is better than nothing!
As with all “dust separation” and “dust collection”, the “dust and particles” in containers and filters are dangerous! They should be handled outside with the human upwind of the stuff or wearing a 0.3 micron HEPA filter mask. Try, VERY HARD not get exposed to the stuff! Some people vacuum their clothes and wash their hands are emptying containers and changing filters.
mark
P.S.
There is one commercial vacuum cleaner on the market that uses a water trap - Rainbow. The design dates from the 1929. I used one for many years.
The Rainbow is split into two chambers. The upper chamber is the true vacuum. It pulls the air in. The air is sent to a separate chamber, the water trap. The upper and lower chambers each have an impeller - run by a single electric motor. The impeller in the upper chamber is nothing to write about - it pulls air. The lower chamber impeller is… amazing. It was patented at one point; I don’t know the current state.
The lower chamber impeller - the water trap - is design to literally induce a tornado and to do something very cool. The impeller/tornado sucks up water and breaks the water stream into tiny droplets and water vapor. The air coming out of the upper chamber is blown through the suspended water and is exhausted. The water droplet and vapor catch the particles and they fall to the water below. Excellent filtration. No HEPA filter.
Yes, one has the “wet mess” to clean up when you’re done but the filtering is excellent… and your home vacuum is a wet/dry vac! They are expensive but last for decades because the design is so simple.