The pipe fitting that you need for this application is commonly availible in
Blighty and costs peanuts. It comes in BSP (British Standard Pipe threads )
sizes from 1/2 inch upwards and is used as a normal tank connection in both
hot cold water tanks. Threads are parallel and these connections are
reliable. Strangely, pipe sizes have not been metricated here other than for
copper pipe which has been adapted to the nearest metric unit.e.g. the old
1/2inch i.d. copper is now 15mm o.d.copper. Even the French use BSP pipe
fittings!
I am not sure what standard pipe thread you use but if it is American
Standard Straight Pipe thread, then these look compatible. eg. 1/2inch and
3/4 are both14 tpi in both systems.
The point of all this is that if you can use BSP flanged fittings for tank
connectors the I will arrange to ship them to you at cost to save you
farting around with brazing.
email me direct on [EMAIL PROTECTED]
ken
---
-- Original Message -
From: [EMAIL PROTECTED]
To: biofuel@yahoogroups.com
Sent: Sunday, January 19, 2003 5:55 AM
Subject: [biofuel] Re: Drum Modification
I've been thinking about the weldless approach a lot lately as I just made
some new processors (I demo'ed one at the
huge anti-war rally in san fran today, I played around with a 12V pump for
an agitator (not a good enough one
though it did make some biodiesel while we ran our mouth about how others
should too), showed off the anti-war
machine, flew banners off of our cars and trucks, and otherwise made
fools of ourselves along with a contingent of
other biodieslers.
Anyway I think there are times when a weldless approach is preferable and
times when brazing in fittings makes
more sense.
I was fooling around trying to figure out some cheap variations on
processor design, pushing the bung-side-down
and weldless approach as far as I could take it. I have an excess of
closed head drums available which is an unusual
factor- I got to cut some of them up just for the bungs, and then played
with attaching the bungs to other drums...
(After two or three months of processor experimenting, I have developed
some kind of obsessive disorder or
something- I visualize plumbing stuff and weldless processors in different
configurations all day and allnight in
my head- I dream about these things, I notice that no matter what I am
doing, in the backof my consciousness I seem
to have some kind of visual of fittings, drums, and pipe layout
configurations running through my head. I REALLY
need to get a life! really!)
Having just gone through all of the options I could think of I'm pretty
convinced of the following:
1. if you want to go weldless for a 'starter' processor, use the
bungsidedown approach (I don't believe plastics are a
good idea at all for processors, having watched my friend melt a plastic
tank processor, and watched a lot of others
leak)
2. brazing is the easiest way for an amateur metalworker to attach
fittings to the thin metal of a drum with the
least risk of leaks
3. various compression-fitted connectors spring leaks (and I've as I said
experienced this a lot)
4. One problem with the male-female connector approach is that (in the US
at least) pipe thread is tapered. SO
there aren't a lot of ways to get a really tight fit with standard
plumbing parts- you can screw two plumbing
fittings together but they'll bottom out before there's enough contact to
make this a safe way (using commonly
available gaskets) to put a fitting on the bottom of a drum that will
contain 400 pounds of hot biodiesel. Bungs, by
the way, do not seem to be tapered. THis allows for a pipe thread to be
extended quite far through a bung, at which
point you can attach more plumbing to the protruding threads on the inside
of the drum- there's times when this is
useful, dip tubes and other intakes inside of drums, heat exchangeers, and
more. There ARE a couple of 'nuts' that
screw on to pipe thread, and can be run further than most other fittings-
one is just a pipe thread nut that can be
difficult to find in hardware stores and isn't used often in plumbing, and
the other is a lightweight lockring from
electrical conduit fittings- the lockring/nut (cant remember actual name)
that you tighten inside an electrical box
in EMT or rigid applications is threaded like pipe thread, and this is
useful for light-duty applications with a
gasket.
If you spend money to send away to a catalog place for a gasketed spigot
adaptor (they do make a few things like
this- it;s a fitting that gets a lockring and an gasket -ring, I haven't
been albe to find a good one locally, though
MacMaster-Carr has them I believe) you might as well spend the same money
on getting some local shop to braze a
fitting on for you so that it will be permanently leakproof
5. However if you just need a place to stick a fitting above the liquid
level- ie the top of your sight tube, or a
return from a pump in a pump-agitated processor- screwing plumbing
