On Wed, 20 May 2009 00:50:15 -0700, Gunner Asch wrote:
On Wed, 20 May 2009 02:15:40 -0500, James Waldby ... wrote:
....
Some plasma tables use air bladders to displace water to raise or lower
the water surface level; others have a two- compartment tank with no
bladder, and use compressed air to push water out of the lower tank to
raise water surface level in the upper tank. The top part of the lower
tank is air-tight and the water transfer pipe picks up near the bottom
of the tank.

I think Karl's early post in this thread talked about a bladder, but
some more recent ones give me the impression there won't be a bladder,
just the two-part-tank arrangement, with a big flat plate dividing the
parts. Although I don't know whether his plan has the angle iron
supports above or below the flat plate, if the supports were above it I
don't see how he would get it out again later (as he apparently wants to
be able to do, for maintenance). So, I think he is looking for
fasteners to hold the plate down, air tight up to say 3 psi, on top of
angle iron supports. It seems like an alternative would be a framework
that lays in on top of the plate and bolts to the tank sides with nuts
on the outside of the tank. This would stiffen the tank sides and
wouldn't make any holes in the plate, while holding it down against
gasket material on the angle iron. Or, if angle iron were welded along
the edges of the separator plate, the gasket would be vertical, captive
between the angle and the tank wall. If holes are drilled in place and
if the walls taper out just a bit, then bolts will fit ok and
assembly/disassembly is possible.


But.....why bother with all the internal workings? Yu need at
most....3" of water under your work piece and an inch of freeboard to
make sure it doesnt drip on the floor.

Don't know why.

IRRC...its only going to be 6x10 feet in size...and its NOT going to be
used for rocket motors and large assemblies.

If he is actually going to cut assemblies...thats another story..but
then he is going to have to have a large liftable gantry for the torch
and moving parts and that becomes a much larger issue.

Im not seeing where all the complicated stuff is involved here.

Likewise. I was merely explaining what I think Karl is looking for,
not why.

Shrug..while not a "pro"....Ive a bit of hands on with plasma tables and
the side mounted milling cutters for using the same hardware for cutting
plastics and wood on the other side of the tank.


Gunner, scratching his head in a bit of confusion apparently.
....

--
jiw