How Many Gs?

That's as meaningless as the leaf blower adds that say our blower puts out up to 100MPH wind.

And wouldn't you think that after all this time the soap makers would have made the soap as "new" and as "improved" as it could possibly get?

If I've said it once, I've said it a million times, it's BS plain and simple.

I guess my point was not where in the machine could it happen, but why would any rational person even ask?

"I'm not clear where in the machine this is supposed to happen, but....anyone have any thoughts on this?"

I'm sorry If I implied that you were anything other than competent.

The flowing calculations you provided were interesting.

I'm sure you're still sharp as a tack.

Thanks, I was a little exited by the safe arrival of two new granddaughters this afternoon or I might not have been so pushy.

My knowledge of cyclones is from industrial plant. The velocity is already in the inlet tube of the cyclone, It has to accelerate to the speed with which it is going to run around the wall, causing the centripetal force. The particles are thrown at the wall and drop down because the air spreads out, lowering it's velocity, the dirt moves down and the air moves up through the cyclone. That seems to require an early acceleration in, or before, the inlet tube.

Congratulations!!!!!on the granddaughters.

I worked with wet cyclone filters in printed circuit board plants.

Do you mean to tell us that somebody would use hyperbole and sloppy mathematics to produce a sales slogan, shocking!!

I suspect that the sloppy math is actually trying to be applied to the centripetal acceleration required to keep the dirt suspended in air and is not the actual acceleration experienced by anything inside this machine. So with the radius of the top of each of the funnels at about one inch in radius, that would mean that the radial wind velocity should be, a*r=v² → √(136,000 * (32 ft/ sec²) * 1/12 ft)≈ 600 ft/sec ≈ 410 mph. For this to be accurate though, this must be the air flow circular velocity tangential to the axis of the cones and not the axial flow along the cone.

'Cyclonic' implies the air is spinning and that this is where the Gs come from -- from the centripetal acceleration.

So let's consider: ω²r = 136,000 * 980 cm/s²

[980 cm/s² = 1 G; ω = angular speed; r = radius of the angular motion]

If r = 10 cm (the radius of the 'cyclonic' chamber) then:

ω² = 136,000 * 98/s², which gives ω = 3650 radians/second or 581 rev/sec;

Or ω = 35,000 rpm.

I think 35,000 rpm is fast, but I'm not sure that it's unreasonably fast. But does this mean that this is 'real' and that this somehow creates a better vacuuming action? I don't know -- I'd go look at the comparisons made by consumer organizations.

You are right, 35,000 rpm is not unreasonably fast. I have seen a centrifugal compressor impeller (330 mm diameter) rotating at 19240 rpm. It's around Mach-1 tip speed. I have also seen recently turbo-machines running at 57000 rpm but impeller diameter is not known.

Well, if fart was a commercial product they would probably advertise their butt as MACH 2 production machine. S.M.

This reminds me of marketing tactics in the early 80's of stereo amps and inflated RMS claims.

Let's have a straw poll on how many decimal places off the 136,000G figure is...; I'll guess 4. (You guess which direction...)

136,000G's, The unit is made of plastic. Would this not impolde on itself?

I think that it is "Creative" interpretation, to generate so many G's you would need a cyclonic effect which could break the unit.

I believe someone came out with a number hoping noone would notice.

Personally, I really "love" the peak horsepower ratings on a vacuum cleaner or shop-vac(or hoover for you folks on the other side of the pond). Never mind that a peak horsepower value might be useful for a pile driver, but hardly a machine that is supposed to provide continuous work. My understanding is that when the slimey marketing people came up with this idea, they run the motor up to it's full no-load RPM without any impeller, then they clamp down on the shaft with a dyno and record the peak torque value as the brake clamps down on the shaft as it grinds to a halt. Multiply the two values and presto, a peak horsepower value. Of course, engineering types see right through this smoke screen, understanding that much of that "torque" is just stored rotational energy slamming into the brake. But alas, they all touted this male bovine excrement figure anyways.

Nobody here seems to understand my comment at all. The centripetal acceleration calculation is the force required to keep the dirt suspended in air not what the dirt actually experiences. If it did experience this force then it would not separate from the air stream. Instead the dirt gets flung against the side walls of each conic section at a much more modest force than what is needed to maintain suspension. If the dirt did experience this acceleration in the cone the required deceleration force upon impact with the walls will likely be so high that the dirt will cake and pile up on the walls of the cone.

Oh also the Dyson site incorrectly uses the fictitious force term centrifugal instead of the real force term centripetal.

"...uses the fictitious force term centrifugal instead of the real force term centripetal."

One of my pet peeves regarding anyone who has made it through physics.....especially engineers is the mis-use of terms and centrifugal vs. centripetal seems to be very mis-used.

A few years ago, I went from working in the aerospace industry to working in the medical devices industry. The company I went to work for made ventilators/respirators. They had a product that provided it's own source of pressurized air (instead of using hospital compressed air).

For months I couldn't figure out how their product used what they referred to as a 'drag turbine'. It turned out it was a drag compressor which was spun up with each delivered breath and compressed the air (or air/oxygen mixture) to provide to the patient. I fought a losing battle trying to get everyone to call it a 'compressor' instead of a 'turbine'. I finally discovered why the called it a turbine....because it sounded more high tech than compressor. AAArrrrrrrggggggggg.

Eventually I went back to the aerospace industry.

"I finally discovered why the called it a turbine....because it sounded more high tech than compressor."

The PR folks obviously are running THAT house. But ...

This supports the point I would make about centrifugal vs centripetal as a force nomenclature. It is pretty clear to me that if you are writing for us engineers, it makes more sense to use the more correct term (and sets fewer teeth on edge, too! )

But when you are writing for the un(der)educated, sometimes you have to go with what works.

"The claimed 136,000 G is not preposterous at all."

It is totally preposterous, and completly meaningless, in the context of vacuum cleaner performance. I'm 99 44/100 percent sure.

Maybe they could put an HHO powered motor on it and then advertise it as green, too.

GA. Achieved 56.2% of OP, but with 2 MW power which cannot be thought of for a vacuum cleaner. Compressors need to develop pressure, and may have several stages made of heavy parts to to withstand. Whereas vacuum cleaner has just to throw a small volume. I guess, of a vacuum cleaner with 500 m3/hr flow rate and one hundredth of pressure rise compared to compressor, it may be possible to achieve 136000 Gs in just about a kW.