Yes- that’s what most experts
believe contributed to the sinking of the Thresher. Ice formed on screen
filters when they tried an emergency blow, stopping the flow of air.
But they weren’t using air as “dry”
as there should be in a scuba cylinder. Seamagine subs have used a HP system
for years with no problems.
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of ojaivalleybeefarm
@dslextreme.com
Sent: Thursday, April 19, 2012
10:26 AM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] HP
air
Is there any danger of freezing when blowing ballast at that high a
pressure?
On Thu, Apr 19, 2012 at 6:17 AM, Greg <greg@precisionplastics.com>
wrote:
Regarding use of high pressure air to blow ballast tanks, you can
use a regular fill adapter and eliminate the scuba regulator. Make sure that
all components in the system are rated for sufficient pressure. Swagelok has
needle valves and fittings rated for 5000 psi (and more) that are readily available.
Greg
WIth regards to
the tubing and pipework questions. Ive just been over all this myself and
with help from the group, i think i know whats needed now.
The captains plans
show copper tubing which is a low pressure system. General
concensus is to ditch this idea and go for stainless steel as Jon says.
Also, people tell
me that a high pressure system is better as you get faster blowing of
tanks. But, the high pressure port on a standard scuba reg is not big
enough to deliver a decent amount of air.
So, i have ordered
all my parts and expecting them to arrive tomorrow. I'lll post a pic on
my website of it all as soon as it arrives.
I am using 2x
scuba tanks piped via whips into a manifold block.
Then i have a reducing regulator into the system so i can dial
up whatever pressure i want, up to full tank pressure. The pipes are all
parker 350bar stainless pipes with swaged joints. Most of the pipe
is 6mm but does change to 1/2inch for the vbt parts. After that the actual
configuration of the pipe system is the same as the plans.
However, Emile has
a system that i believe is better an you may be able to use this. He has
tanks mounted outside. The system uses a low pressure ports on
standard scuba 1st stages but as its outside, is always delivering correct
ambient pressure. The advantage is tanks outside out of the way, and also
only pressure you actually need in the pipework. Correct me if im wrong
there Emile!
On 19 April 2012
07:03, Jon Wallace <jonw@psubs.org>
wrote:
Hi Scott,
Sorry to hear about your accident. I got hit by a car while riding my
motorcycle back in 2003 and can vouch that it's not fun.
I believe conventional wisdom is to forgo the copper and use stainless
steel. The K-600 has SS plumbing throughout.
The problem you're going to have with putting the vent valves internal is
requiring two penetrations for each valve (inlet and outlet for air) instead of
the one penetration for the valve stem. I personally do not care for
K-boat vent configuration and am going to try to come up with an electric or
compressed air modification. Vance Bradley was working on a ballast tank
vent design at one time but I haven't heard anything about it for a while.
I like the DC breaker box idea. I might think about that myself.
200psi is 449 feet sea water. Since the K-350 is only rated for 350 feet,
using the 200psi first stage shouldn't be a problem. However, yes if you
drop to 500 feet then water would infiltrate the system and you won't be able
to use your ballast tanks because the outside pressure is stronger than the
first stage. There's a very simple technique to prevent getting in this
situation however, just don't dive in any area in which the water depth exceeds
350 feet.
Not sure what you mean regarding the motor pods since the plans call for 1-ATM
housings not oil-filled housings. We definitely could use a good
white-paper or photo-journal that describes how to do it. It's fairly
simple but I can sympathize with you, when you aren't familiar with it the
concept can be confusing exactly how to perform it. I have some photos of
JimK's Bionic Guppy motors which are oil filled. Let me find them and
post them and it should help.
We're scheduled to go to Muskegon
Michigan for the convention this
year and I'm working out the final plans. However, I sent out a request
for speakers and got no response. Unless we get 3 or 4 people to present
topics there won't be any need for technical sessions. That leaves the
potential for sub diving but with the exception of some local folks in the area
I suspect gas prices are going to curb any subs that might have otherwise
considered the trip. Unfortunate since the facility has the resources to
support us for diving. In any event, I'll be sending out notice in a week
or so for registration. If we get to end of May without speakers or subs
then we'll cancel this years event and wait until more people are willing to
participate.
Jon
On 4/18/2012 11:31 PM, Scott Waters wrote:
Hey everybody,
I've been pretty quiet on the pusubs form. A little update on myself and KW350
Trustworthy. For those of you who remember I got ran over and suffered a really
bad leg injury. I went though surgery in November to remove peices of my ankle
and reshape my cartilage and was doing better, but am having complications
again, so surgery again may be comming soon. I haven't let that stop
me (just slow me down), but I have been making good progress on my sub. I'll be
uploading pictures soon. I also got engauged just recently! I proposed 35 feet
under water while scuba diving in Key
West. Good thing is my girlfriend is a excellent
welder and scuba cert, so I might actually be getting more done on my sub
rather than less with a wife. haha. I have ran into a few questions though and
I though I would ask everyone. Here they are:
*For the copper tubing on the blueprints is it best to use compression fittings
or flare fittings?
*Is there anything wrong with running the vent controls internaly so the ball
valve is on the inside rather than a trough hull with the valve on the outside?
*I planning on putting in a DC breaker box on the inside of the sub so you can
reset circuts (in the rare ocasion) rather than fuses in the battery
pods. Does anyone see any problems with this?
* The blueprints call for "1st stage Dacor 200 Regulator" to
take the pressure down from 3000psi out of the scuba tanks. I believe that
means it brings the pressure down to 200psi. What happens if the sub has an
accedental drop to say 500 feet where the pressure is greater than 200psi?
Wouldn't the water rush in rather than air go out? Maybe I'm missing something.
*The blueprints for the oil compensated motor pods confuse the heck out of me.
I have them built, but am pretty much lost as far as how to make the things
work. I'm hoping to see some of your subs at the next conference or
something and perhaps I'll get it then. I think seing them completely finished
and filled with "oil" would help me. would help me alot. Any help on
this would be really appriciated. This reminds me, are we having a psubs
conference this year? I've heard about lake Michigan, but besides discussion,
haven't heard much. If help is needed putting it on, I'd love to help.
Thanks in advance for the help!
Scott Waters
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