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Seismic air cannon article link

Posted: Sun Sep 30, 2012 4:43 pm
by Solar

Towed Sisemic array

Posted: Sun Sep 30, 2012 11:26 pm
by Technician1002

Re: Towed Sisemic array

Posted: Sun Sep 30, 2012 11:36 pm
by jackssmirkingrevenge
No mention of air cannons though...

http://woodshole.er.usgs.gov/operations ... airgun.htm

Turns out its a piston valve :D

Image

Image

Wikipedia suggests 2,000-3,000 psi :shock:

Posted: Mon Oct 01, 2012 11:37 am
by ramses
Looks like they could do with a bigger pilot valve...


Although, they probably use the pilot as an air spring bumper.

Posted: Mon Oct 01, 2012 11:53 pm
by jackssmirkingrevenge
If you look at the way the rear of the piston is shaped and how it fits into the housing there definitely is an air bumper element.

However interestingly it does not appear to be an exhaust valve though, rather the pressure differential is created by the solenoid increasing the pressure on the front side of the piston face, as opposed to reducing the pressure behind it - so it's more of a pop-off valve if you think about it.

Posted: Tue Oct 02, 2012 12:15 am
by ramses
jackssmirkingrevenge wrote:so it's more of a pop-off valve if you think about it.
Very true. I completely missed that itty bitty air channel over on the right. It seems the leakage on the sides of the "triggering piston" even dissipate some of the KE through an air dash-pot type mechanism.

Posted: Tue Oct 02, 2012 12:19 am
by MrCrowley
Now that's pretty cool. Didn't pick up either of those two things mentioned by you two (JSR & ramses) the first time I looked at it.

Posted: Tue Oct 02, 2012 12:33 am
by POLAND_SPUD
However interestingly it does not appear to be an exhaust valve though, rather the pressure differential is created by the solenoid increasing the pressure on the front side of the piston face, as opposed to reducing the pressure behind it - so it's more of a pop-off valve if you think about it.
WTF?
it's just a positive pressure piloted piston valve

Posted: Tue Oct 02, 2012 1:05 am
by jackssmirkingrevenge
POLAND_SPUD wrote:it's just a positive pressure piloted piston valve
Isn't that what I said.

Image PLS

:D

Posted: Tue Oct 02, 2012 7:50 am
by POLAND_SPUD
so it's more of a pop-off valve if you think about it
how is that more of a pop-off? it would be more of a pop off valve if it opened at X pressure but it has a control valve

comparison fail

Posted: Tue Oct 02, 2012 7:52 am
by jackssmirkingrevenge
POLAND_SPUD wrote:how is that more of a pop-off? it would be more of a pop off valve if it opened at X pressure but it has a control valve

comparison fail
The flow from the solenoid increases the pressure on the front face of the piston, which causes it to "pop", or rather in this case, "WHOOOOOOMPH!!!".

Ok, it's a Whooooomph-off valve :D