[PSUBS-MAILIST] Gauge for outside viewport?
Hugh Fulton via Personal_Submersibles
personal_submersibles at psubs.org
Wed Oct 7 02:19:40 EDT 2015
Gauges are filled with oil when you want some dampening of the needle. Like on compressors. Also helps longevity in salt water or corrosive atmosphere environments.
The more air they have the more accurate because if there is no air bubble in the gauge the oil has to escape from the housing as the bourdon tube expands and the pressure of exhausting the oil will cause an inaccuracy. ( mostly in low pressure gauges). If they are full you end up with dribbles. They generally have a rubber bung on the top. Also if you fill it with oil and have it outside the sub you will have the same pressure inside and outside the bourdon tube and it wont measure.
Hugh
From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org] On Behalf Of Alan James via Personal_Submersibles
Sent: Wednesday, 7 October 2015 6:13 p.m.
To: Personal Submersibles General Discussion
Subject: Re: [PSUBS-MAILIST] Gauge for outside viewport?
I saw some oil filled pressure gauges today.
The oil only went 3/4 or so up the dial face.
I asked why it didn't completely fill the inside, but the sales person couldn't tell me.
We surmised that the purpose of the oil was as a buffer in case of explosion.
So if you find an oil filled gauge it is not necessarily going to be full or pressure
resistant.
Cheers Alan
_____
From: Private via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Sent: Tuesday, September 22, 2015 12:30 PM
Subject: Re: [PSUBS-MAILIST] Gauge for outside viewport?
Light from inside, it'll be right up against the window.
> On Sep 21, 2015, at 8:09 PM, Pete Niedermayr via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
> What about illumination ?
>
> Pete
> --------------------------------------------
> On Mon, 9/21/15, Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
> Subject: Re: [PSUBS-MAILIST] Gauge for outside viewport?
> To: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>
> Date: Monday, September 21, 2015, 6:35 PM
>
> It would
> go outside one of the CT viewports. Specifically, the one
> that looks back toward the stern and is therefore seldom
> used. The tank pressure is something I normally look at just
> once before a dive. You want to be able to see it if you
> want to, but it's not a frequent-use item I would put
> right in front of the pilot where real estate is most
> precious.
> So far I
> still haven't located a liquid filled SPG. The one
> Stephen suggested is for sale in Germany but I haven't
> located it here yet.
>
> Thanks,
> Alec
> On Mon, Sep 21, 2015 at
> 7:08 PM, Pete Niedermayr via Personal_Submersibles <personal_submersibles at psubs.org>
> wrote:
> Alec,
> Where are you thinking of mounting the gauges ? Outside one
> of the conn viewports ? Outside the dome ? Or 2 sets for one
> each ?
>
>
>
> Pete
>
> --------------------------------------------
>
> On Mon, 9/21/15, Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org>
> wrote:
>
>
>
> Subject: Re: [PSUBS-MAILIST] Gauge for outside
> viewport?
>
> To: "Personal
> Submersibles General Discussion" <personal_submersibles at psubs.org>
>
> Date: Monday, September 21, 2015, 8:34 AM
>
>
>
> Exactly.
>
> The valves to blow ballast are outside and operated via
>
> through-hulls.
>
> On Mon, Sep 21, 2015 at
>
> 8:57 AM, James Frankland via Personal_Submersibles <personal_submersibles at psubs.org>
>
> wrote:
>
> >1) I
>
> have a bunch of oil filled gauges lying around, but if
> they
>
> are left in any position other than with the rubber caps
> at
>
> the top, they leak all over the place. The shelf they
> live
>
> on is covered with oil, so I'm just not confident
> they
>
> will >keep the oil inside in the
>
> field. Yes, I suppose so. The ones
>
> I have drip. I thought i'd sprung a minor hull leak
> at
>
> first... >2) Yes,
>
> SCUBA tank gauges have a tiny orifice in their hose
> fittings
>
> for just that purpose, to prevent a broken instrument
> from
>
> emptying your tank too quickly. That is good and I plan
> to
>
> use it on the sub as well. However, the problem
>> still
>
> persists that SCUBA gauges can only be taken to under
> 500
>
> feet. I came across tech diver accounts of gauge issues
> such
>
> as the plastic faces buckling and pinning the needle, or
> the
>
> whole enclosure imploding at about 400
>
> >feet. oh. Are you not having
>
> the HP lines inside the sub at all? Controlling the
> air
>
> with a through hull?
>
> RegardsJames
>
> On 21 September 2015 at
>
> 13:20, Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org>
>
> wrote:
>
> Hi James,
>
> 1) I
>
> have a bunch of oil filled gauges lying around, but if
> they
>
> are left in any position other than with the rubber caps
> at
>
> the top, they leak all over the place. The shelf they
> live
>
> on is covered with oil, so I'm just not confident
> they
>
> will keep the oil inside in the field.
>
> 2) Yes, SCUBA tank gauges have a
>
> tiny orifice in their hose fittings for just that
> purpose,
>
> to prevent a broken instrument from emptying your tank
> too
>
> quickly. That is good and I plan to use it on the sub
> as
>
> well. However, the problem still persists that SCUBA
> gauges
>
> can only be taken to under 500 feet. I came across tech
>
> diver accounts of gauge issues such as the plastic
> faces
>
> buckling and pinning the needle, or the whole enclosure
>
> imploding at about 400 feet.
>
>
>
> Thanks,
>
> Alec
>
>
>
> On Mon, Sep 21, 2015 at
>
> 5:03 AM, James Frankland via Personal_Submersibles <personal_submersibles at psubs.org>
>
> wrote:
>
> Hi Alec, I have a
>
> couple of thoughts. 1. The
>
> gauges I have are chemical protected, so they have an
> oil
>
> filled diaphragm separating the inlet line from the
> gauge
>
> internals. Then there is a small vent hole at the top
> of
>
> the gauge. You could attach a rubber hose\bladder
> to
>
> this vent hole, top it up with glycerine or whatever
> the
>
> gauge is filled with and have a fully compensated valve
> with
>
> a bladder. 2. How about using just
>
> a normal scuba gauge which will probably be perfectly
>
> fine. But, just make a small adapter that screws onto
> the
>
> gauge and has only a tiny little orifice to allow the
> input
>
> air. That way if the gauge did ever fail, it would
> only
>
> bleed out air slowly and you'd have time to blow
>
> tanks. If you are using a scuba 1st stage and piping
> from
>
> the HP port (I assume your not and are plumbing
> straight
>
> into tanks) then the scuba HP already has this small
> hole
>
> for the same reason. Also, it would
>
> be easy enough to test a gauge. Find somewhere deep
>
> enough and take a fishing rod and a packed
>
> lunch! Im fairly sure Emile has
>
> external gauges on his sub and its a 200m diver. He
> could
>
> maybe advise? Just a thought.
>
> Kind Regards
>
> James
>
> On 21 September
>
> 2015 at 06:51, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org>
>
> wrote:
>
> Hi Alec, New sub ?
>
> I must have missed that ! do you have any
>
> details? BTW, I received that big gage !
> It's
>
> huge ! I hope I can get it in through the hatch !
> As
>
> it is designed for sea water I assume all I have to do
> is
>
> plumb it in, will salt water getting into the tubing
> cause
>
> any problems? Brian
>
>
>
> --- personal_submersibles at psubs.org
>
> wrote:
>
>
>
> From: Alec Smyth via
>
> Personal_Submersibles <personal_submersibles at psubs.org>
>
> To: Personal Submersibles General Discussion
>
> <personal_submersibles at psubs.org>
>
> Subject: [PSUBS-MAILIST] Gauge for
>
> outside viewport?
>
> Date: Sun, 20 Sep
>
> 2015 23:03:02 -0400
>
>
>
> I have an
>
> interesting thing to think about and wondered if any of
> the
>
> PSUBS brain trust might have a suggestion.
>
> One of the simplifications on my new
>
> sub is that all HP air lines are external, aside from
> the
>
> BIBS (which is normally shut off anyway). Thus, I'm
>
> looking for a 3,000-4,000 psi gauge to mount outside a
>
> viewport, like in the Pisces photo that I'll paste
>
> below. In case my paste doesn't come through, it is
> the
>
> one at the top of the following article: http://www.nytimes.com/2015/09/15/science/piloted-deep-sea-research-is-bottoming-out.html?_r=1
>
> The first thing that came to mind
>
> was to use a SCUBA submersible pressure gauge, but the
>
> problem is these are normally 1 atm dry enclosures of
>
> limited depth rating. There is generally little
> information
>
> posted about how deep they'll go, but what I did
> find
>
> was mentioned 260 feet for the plastic ones and 490 feet
> for
>
> the brass variety. This is a 1,000 foot sub.
>
> The second idea was to use oil
>
> filled gauges intended for above-water use. But these
>
> generally have considerable bubbles in the oil, are not
> very
>
> good at keeping the oil inside, and have other hardware
> not
>
> intended to live long in sea water.
>
> Any suggestions would be most
>
> welcome!
>
>
>
>
>
> Thanks,
>
> Alec
>
>
>
>
>
>
>
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