James,Couldn't you put an automatic check valve in the line that leads to the gauge ("surge protector") to prevent the HP air from hitting the gauge so you don't have to do it manually each time?JimIn a message dated 11/8/2011 4:36:20 A.M. Central Standard Time, jamesf@guernseysubmarine.com writes:Hi guys,Sorry for late reply with this, ive been on a misserable course for work.Alec. Yes, im also concernded about hp air passing the gauges. Hence the question. But, i suppose i could put a ball valve in the line before the gauge and close it before operating the hp air. Bit of an extra step, but would protect the gauges, plus id have to remember to open the valve again after or i'd get incorrect readings. But a possibility.Vance. Im not 100% sure i understand. Do you mean use the bottom bulkhead fitting and separate it out? If so, that fitting goes into the VBT, which could be full of water, or air and at various pressures? Surely you must mean something else?Alan. Again, sorry but i dont understand how the gauge could read 10ft short. I suspect your thining the hp air would always be on. It would be connected to a diving tank and valve, so the check valve would only be stopping water going into the hp piping, it wouldnt have any pressure on the "air" side until i cracked the tank.Good ideas for both the flood valve fitting and overpressure valve. But unfortunately, both wont fit to a 1/4 or 1/2 inch pipe.I think im going to "T" it off from the forward ballast tank and have the extra ball valve to shut off the valves to protect them from the tank blow.Also!, has anyone goot a better copy of page K-350 - 13 pipe arrangement i could have? I have a copy that came with my plans, but its such a dreadfull photocopy that i cant read half of it. I can work it out of course, but it would be nice to actually see what the official plans say.Many thanks as always,James
On 31 October 2011 21:24, Smyth, Alec <Alec.Smyth@compuware.com> wrote:
Hi James,I would worry about the effect of a ballast blow on your depth gauge. In addition, my suggestion would be to put check valves directly on the through-hull of each MBT, rather than use a ball valve as indicated in your diagram. In effect, you then have automatic hull stops. I've found a through-hull such as would be needed for a depth gauge can be welded in with only a local touch-up required to the paint. But here's another idea... do you have a through-hull for an overpressure valve? I used to have my overpressure valve and depth gauge share the same through-hull.Thanks,
Alec
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From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of James Frankland
Sent: Monday, October 31, 2011 1:28 PM
To: personal_submersibles@psubs.org; member-forum@psubs.org
Subject: [PSUBS-MAILIST] HP Stop valve for gauges.Hi All,Can i ask people's opinion on this. Due to an oversight on my part, i am missing a through hull for a depth gauge.So, i have an idea. I was thinking of putting the gauges on the same line as the HP air for the forward tank. In this configuration. See fantastic picture attached (i am at work so i only have microsoft paint). Hope the pic makes it through.The idea is i have the through hull, stop valve, t piece (or even a "Y" piece) leading to 2 x redundant chemical protected gauges on one "t" and on the other, the check valve followed by the hp air. Easier to see in the picture.This should allow water to the gauges while not filling the whole line to the hp tank.
The check valve is 400 bar with a cracking pressure of 5psi.The only problem i can see is that when blowing air, it may interfere\damage the gauges? Bearing in mind they are chemical protected so have a diaphram that will protect them from the water itself.Unless anyone has any better ideas. (I will have a normal diviers gauge outside, but i want proper gauges inside).ThanksJames