How can I build a better pulsed pressure generator?

Along the same line Carl is following, you might look at fuel injector valves. They are quite fast, in the ms range.

tm

What about the old blacksmiths bellows ?? Rigged up with a variable motor/drive.

Borrow a paintball gun?

Mark L. Fergerson

That's interesting. Could grabbed video frames be compared to show the fringes?

You can get pneumatic servovalves, don't know prices though.

Asco SERVOMATIC, for example, 150Hz BW. Still need a compressor of course, and probably not cheap (WAG $1K +100/-50%)

Best regards, Spehro Pefhany

Plumb a few sub-woofers in series. the loud-noise fans call this arrangement "isobaric"

as I understand it you'd need pixels at or below the scale of the interferance fringes, I don't know how small they're making image sensors. but that's pretty small.

And then you'd have a digitised hologram and need to do computations to render a surface from that.

FYI we get our pumps from Hiblow USA (gotta love the name.) (We use the smallish C-5BN.) George H.

But they could not break an arm 60 times per minute. That's the problem, I need power.

Hmm, that site seems big on marketing claims but thin on real tech info.

Umm ... yes, it would be nice :-)

While this area would be much more accommodating to that compared to much of the rest of California, neighbors would frown if they'd hear rat-tat-tat all day long.

I can imagine the demo to be really fun. Engineers and managers pile into a room, Joerg opens a large suspicious-looking James Bond style briefcase, opens lid, and everyone scrams.

Thanks, but that is still way too weak. It would barely get past 1psi in our application. That's what I had with a similar pump but twice the size. 8 watts won't quite cut it.

Looks like these are Japanese pumps.

Yeah. The compressor draws over 2 amps at 115V and even than would run out if I couldn't pre-charge it to 100psi into a 3gal tank. That provides 5-10mins of operation. Afterwards it has to run for 5-10 minutes ... *RRRRRRRRRRRRRRRRRRRR* ... very loud.

Unfortunately it doesn't result in nearly enugh pressure. Plus they really suffer if you force them down to almost DC. Already blew two serious speakers that way.

I thought about calling Linde and get a quote on a bottle of compressed air, or a dive shop. But then I may be in the news some day, a building with a blast hole in the roof and me in the obituary. 100psi is nothing, my compressor does this and I use up 3gals of that in 5-10mins.

That's what I am doing right now, except with a hacked pressure switch. If you valve could do more than one cylce per second, do you remember what kind and maybe where you bought it?

It doesn't get me away from the compressor noise though.

That would be way too weak in power.

Yup.

Speakers aren't all that bad when at near DC frequencies. Then they essentially become solenoids. The surround seems to be the problem, it can't take that for very long.

That's when mine tore its surround.

Those motors are way, way to weak.