[PSUBS-MAILIST] Scuba Tank DIN connector to JIC

Thu Oct 13 19:59:31 EDT 2016

Correction, you won't be able to put air in your ballast tank
below 200ft with a 100psi regulator inside the hull.
Alan

Sent from my iPad

> On 14/10/2016, at 12:53 pm, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Mark,
> sorry if I am insulting your intelligence here, but if you have a 
> standard regulator inside the hull reducing the pressure to 100
> psi then you won't be able to blow your ballast tanks below 50ft.
> As Steve suggests, a scuba first stage regulator will give you
> 130 psi above the ambient water pressure, enabling you to put
> air in your ballast tanks at any depth.
> Just mentioning this because this mistake has been made before.
> Cheers Alan
> 
> 
> Sent from my iPad
> 
>> On 14/10/2016, at 11:55 am, Stephen Fordyce via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> 
>> Hi Mark,
>> Most SCUBA regulator first stages (the bit that goes onto a tank) will drop the pressure to about 150PSI, and you could happily adjust most of them to 100PSI instead.
>> 
>> Bear in mind a regulator adds lots of different failure modes and if your shutoff is after the regulator you may well lose all the gas in the cylinder if there is a failure.  Probably doesn't matter in your case!  This is also a reason regulators have an overpressure valve (OPV) - in case they fail open and deliver full cylinder pressure into the low pressure downstream line.  Quite important if you don't have a SCUBA second stage (that bit that goes in your mouth) installed.
>> 
>> Also after the regulator there is no way of knowing what's left in the cylinder.  A contents gauge is only useful on the high pressure side.
>> 
>> A useful resource for dealing with SCUBA regulators:  http://www.airspeedpress.com/newregbook.html
>> 
>> The cheapest SCUBA regulators are for argon and/or drysuit inflation.  Ie: https://www.divegearexpress.com/inflation-regulator-w-opv
>> They are not adjustable (but generally set to lower pressure, more like 100-125PSI) and often have slightly less flow.  I don't think the difference would be particularly significant for you.  They also tend to be 200bar DIN - so if you have a 300bar DIN valves they won't fit.
>> 
>> SCUBA regulators for breathing are more expensive, but have higher flows and are meant to be more reliable, and adjustable.  You'd be looking for a DIN "first stage" (they are pretty much all dual 200/300bar compatible) and then you'll have to get a separate OPV. Ie:
>> https://www.divegearexpress.com/regulators-spgs
>> 
>> You'll also need one of these adaptors to turn the regulator outlet into NPT: https://www.divegearexpress.com/adapter-1-4-inch-npt-female-3-8-inch-m
>> 
>> Cheers,
>> Steve
>> 
>>> On Fri, Oct 14, 2016 at 12:55 AM, Mark via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>> Steve,
>>> 
>>> Thanks for the clarification on the DIN connector.  In terms of the pressure regulator, what device do most people use to regulate the air pressure?  Is this something I could purchase from a SCUBA parts supply company?  
>>> 
>>> Regards,
>>> 
>>> Mark Widman
>>> 910-638-5229
>>> 
>>> Sent from iPhone.
>>> 
>>>> On Oct 13, 2016, at 9:17 AM, Sean T. Stevenson via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>> 
>>>> 300 is short for 300 bar, or the recommended maximum pressure of the fitting, indicating that it is a deeper thread than 200/232 bar fittings. The latter can be used with yoke style regulators (CGA-850) by using an insert in the female DIN on the tank valve. The 300 bar connection, being deeper, precludes this but is stronger. Similarly, if you have a 300 bar DIN fitting on your regulator, and screw it into a 200 bar DIN tank valve, it is compatible, but will show a couple of exposed threads which can be entrapment points.
>>>> 
>>>> DIN 477 is the actual thread specification.  Rarely seen in SCUBA equipment catalogs, but necessary if you're going to have a DIN thread machined.
>>>> 
>>>> Sean
>>>> 
>>>> 
>>>>> On October 13, 2016 6:26:49 AM MDT, Mark via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>>> Thanks Steve,
>>>>> 
>>>>> This is exactly what I'm looking for.
>>>>> (1/4" m NPT x DIN 300 m)
>>>>> 
>>>>> Sean recommended a DIN 477 connector, is there a difference (DIN 300 vs. DIN 477)?
>>>>> 
>>>>> Lastly, I would like to regulate the air pressure to something more reasonable like 100 or so PSI.  Can you recommend an air pressure regulator?
>>>>> 
>>>>> Regards,
>>>>> 
>>>>> Mark Widman
>>>>> 910-638-5229
>>>>> 
>>>>> Sent from iPhone.
>>>>> 
>>>>>> On Oct 12, 2016, at 10:27 PM, Stephen Fordyce via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>>>> 
>>>>>> Hi Mark,
>>>>>> I have that sort of thing in my catalogue (TFM Engineering Australia), but being down under, not a lot of point sending them to you in the USA when you get can from the likes of:
>>>>>> http://www.northshorecompressor.com/products/17B477D22-M-NPT-x-DIN-300-M.htmlhttp://www.northeastscubasupply.com/search.php?search_query=DIN+NPT&Search=
>>>>>> 
>>>>>> You might be able to do a bit better if you look around - but avoid the ones with bleeders for your application in ca! se it gets knocked.
>>>>>> 
>>>>>> Cheers
>>>>>> Steve
>>>>>> 
>>>>>> 
>>>>>>> On Thu, Oct 13, 2016 at 6:44 AM, Mark via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>>>>> Hi Sean,
>>>>>>> 
>>>>>>> I have four SCUBA tanks mounted on the outside of the sub.  The SCUBA tanks are used to provide/control air for the external ballast tanks.  The air line runs from the SCUBA tank to a thru hull fitting in the sub (to a control valve) and then back out to the ballast tanks.  I need to acquire a connector from the SCUBA DIN to either NPT or JIC.
>>>>>>> 
>>>>>>> If I can order a DIN 477 to NPT that would suffice.
>>>>>>> 
>>>>>>> Regards,
>>>>>>> 
>>>>>>> Mark Widman
>>>>>>> 910-638-5229
>>>>>>> 
>>>>>>> Sent from iPhone.
>>>>>>> 
>>>>>>>> On Oct 12, 2016, at 3:15 PM, Sean T. Stevenson via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>>>>>> 
>>>>>>>> That's an oddball to find as a single piece, but you can certainly find male DIN 477 to e.g. NPT, and adapt that to a NPT/JIC.
>>>>>>>> 
>>>>>>>> What are you building?
>>>>>>>> 
>>>>>>>> Sean
>>>>>>>> 
>>>>>>>> 
>>>>>>>>> On October 12, 2016 12:49:50 PM MDT, Mark via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>>>>>>> Good afternoon, Psubs team:
>>>>>>>>> 
>>>>>>>>> Do you know if and where I could purchase a SCUBA tank DIN to JIC connector?  
>>>>>>>>> 
>>>>>>>>> Regards,
>>>>>>>>> 
>>>>>>>>> Mark...
>>>>>>>>> 910-638-5229
>>>>>>>>> 
>>>>>>>>> Sent from iPhone.
>>>>>>>>> 
>>>>>>>>> 
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>>>>>>>>> Personal_Submersibles at psubs.org
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