[PSUBS-MAILIST] Pressure Test Chamber

Wed Nov 18 22:41:27 EST 2015

Hi all,
Just wondering if my last post on this subject went though?  I'm curious
about whether the inside-out testing chamber is useful to anyone (and also
to heat from Alan about where to get blue globe cable glands down under).

Cheers,
Steve
On 16/11/2015 1:37 PM, "Stephen Fordyce" <stephen.fordyce at gmail.com> wrote:

> Hey guys,
> If you're going to make a small pressure chamber to go inside the big one
> just for testing penetrators, how about just making your small one so that
> you can screw the penetrator onto the inside of it?
>
> See sketch attached.
>
> I did this to test some cable gland/penetrators I made for underwater
> lights and it was very quick and easy to put together, it was small enough
> that I could use standard black plastic fittings from Bunnings as they were
> rated to something like 100m water depth.
>
> I also found that sealing the end of the cable with liquid electrical tape
> worked fine to prevent leaks through the cable stands at these pressures
> (but only for external pressure!).
>
> Cheers,
> Steve
>
> PS: where/how do you get blue globe cable glands down under??
> On 16/11/2015 6:38 AM, "Alan James via Personal_Submersibles" <
> personal_submersibles at psubs.org> wrote:
>
>> Hank,
>> you are right. My first port of call is to visit a large hydraulic
>> service & manufacturing plant in case they have something
>> lying around, or can suggest anything.
>> I have been reading the penetrator section in
>> "Busby". Apparently the European method is to take the cable
>> right through the penetrator & the American method is to have
>> pins going through. With the European method sometimes they
>> inject resin under pressure inside the individual wire insulations
>> to seal them in case the cable is sheared.
>> G.L. require that there is no leak after a cable breakage, so I
>> think the pin option is better in that case.
>> Busby said most of the failures happened at the pin / wiring interface.
>> I imagine it would be a weak point if you pulled on the cable.
>> The idea of supporting this point with the silicone & casting over
>> the top must have merit.
>> Some manufacturers brazed washers to the pins to stop them
>> extruding through the resin. I don't think I need to worry about that at
>> 500ft,
>> but maybe a few dots of brazing on the pins would help it a bit.
>> Cheers Alan
>>
>> ------------------------------
>> *From:* hank pronk via Personal_Submersibles <
>> personal_submersibles at psubs.org>
>> *To:* Personal Submersibles General Discussion <
>> personal_submersibles at psubs.org>
>> *Sent:* Monday, November 16, 2015 7:46 AM
>> *Subject:* Re: [PSUBS-MAILIST] Pressure Test Chamber
>>
>> Alan,
>> I was looking around NZ online for a hydraulic cylinder, you guys have it
>> tough for surplus stuff.
>> Hank
>>
>>
>>
>>
>>
>> On Sunday, November 15, 2015 11:04 AM, Alan James via
>> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>
>>
>> Thanks Hank,
>> I like your idea of the small air chamber to test the through hulls,
>> I was intending to screw them to the inside of a fitting in the end cap /
>> lid.
>> Will make inquiries re cylinders.
>> Alan
>>
>> ------------------------------
>> *From:* hank pronk via Personal_Submersibles <
>> personal_submersibles at psubs.org>
>> *To:* Personal Submersibles General Discussion <
>> personal_submersibles at psubs.org>
>> *Sent:* Monday, November 16, 2015 2:30 AM
>> *Subject:* Re: [PSUBS-MAILIST] Pressure Test Chamber
>>
>> Hi alan,
>> My cylinder is very unusual because it is light weight for a crane.  But
>> yes, you leave the piston in, if it is double acting and either all of the
>> rod or cut the excess off, I would leave it intact.  I can either use water
>> or air, normally I think you would fill with water for safety also to
>> locate a leak in your test part.  I use air because the cylinder is safe
>> and rated.  If you find a double acting cylinder, you can also remove the
>> piston and just use the piston nut and washer to hold the rod in from
>> pushing out.  Then you can use the second port for filling with water while
>> it vents out the opposite port.  Then you just need a tee with gauge and
>> valve.  You can pressurize it with your scuba tank or a pressure washer.
>> The scuba tanks make the most sense  if you fill with water first so you
>> displace all the air.  You will need to make a small air chamber to go
>> inside if your testing your penetrators.  Just take a pipe threaded at both
>> ends, screw a cap on one end and a fitting at the other that will except
>> your penetrator.   This way you have water pushing against the penetrator
>> with air on the opposite side of the penetrator.  So long story, but try
>> to find a double acting cylinder, either screw on top or tie rod type  with
>> four long bolts is also fine.   Easy to do with no welding or machining.
>> Hank
>>
>>
>>
>>
>>
>>
>> On Saturday, November 14, 2015 10:26 PM, Alan James via
>> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>
>>
>> Adam / Hank,
>> received Adam.
>> Hank how does your hydraulic cylinder test chamber work?
>> Have you left the piston & rod in it extended & then pressurize the
>> cylinder with the piston?
>> Do you fill your pressure chamber with water?
>> Any details appreciated.
>> Thanks
>> Alan
>>
>> ------------------------------
>> *From:* Adam via Personal_Submersibles <personal_submersibles at psubs.org>
>> *To:* Personal Submersibles General Discussion <
>> personal_submersibles at psubs.org>
>> *Sent:* Sunday, November 15, 2015 4:42 PM
>> *Subject:* Re: [PSUBS-MAILIST] Pressure Test Chamber
>>
>> Test
>>
>> On Sat, Nov 14, 2015 at 9:08 PM, Alan James via Personal_Submersibles <
>> personal_submersibles at psubs.org> wrote:
>>
>>
>>
>> Hank,
>> that sounds a really good idea.
>> Will have a look for something suitable during the week.
>> Cheers Alan
>>
>> ------------------------------
>> *From:* hank pronk via Personal_Submersibles <
>> personal_submersibles at psubs.org>
>> *To:* Personal Submersibles General Discussion <
>> personal_submersibles at psubs.org>
>> *Sent:* Sunday, November 15, 2015 2:37 PM
>>
>> *Subject:* Re: [PSUBS-MAILIST] Pressure Test Chamber
>>
>> Alan,
>> Just buy a hydraulic cylinder, works a charm and there is no welding plus
>> it is rated.
>> Hank
>>
>>
>>
>>
>>
>> On Saturday, November 14, 2015 6:13 PM, Alan James via
>> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>
>>
>> Thanks Hugh,
>> I am making up 8 lights (including navigational) & their connectors
>> + thruster through hulls so will have a minimum of 29 items to test.
>> It would probably pay for me to have my own.
>> Do you want to sell your stuff? Otherwise I was going to head to a
>> pipe manufacturer & see what bits I could pick up.
>> Cheers Alan
>>
>> ------------------------------
>> *From:* Hugh Fulton via Personal_Submersibles <
>> personal_submersibles at psubs.org>
>> *To:* 'Personal Submersibles General Discussion' <
>> personal_submersibles at psubs.org>
>> *Sent:* Sunday, November 15, 2015 10:08 AM
>> *Subject:* Re: [PSUBS-MAILIST] Pressure Test Chamber
>>
>> Alan,
>> I have a deal for you.
>> I have the cylinder, pump and gauges but need the flanges made etc.
>> You can use it whenever but I get to keep it.
>> Hugh
>>
>>
>>
>>
>> *From:* Personal_Submersibles [mailto:
>> personal_submersibles-bounces at psubs.org] *On Behalf Of *Alan James via
>> Personal_Submersibles
>> *Sent:* Saturday, 14 November 2015 5:37 p.m.
>> *To:* Personal Submersibles General Discussion
>> *Subject:* [PSUBS-MAILIST] Pressure Test Chamber
>>
>> Hi all,
>> I need to find or make a test chamber a minimum
>> of around 6" internal diameter & about 12" high.
>> I could go a lot larger than that if something was suitable.
>> I don't need to test above 400 psi.
>> Anything off the shelf that I could cannibalize?
>> Or any ideas on construction.
>> Cheers Alan
>>
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