Gas shut-off

[Graham_Wright]

Propane bottles come with a screw down valve on top and a side connection for a regulator (or hose connection).

If the bottle is in a sealed locker outside the accommodation and vented to the atmosphere directly, in accordance with the regulations, has anybody any suggestions on how to turn the valve from inside the cabin. A half turn is probably insufficient so that rules a out a simple 90° lever job.

I know I can use a separate isolator valve (maybe a ball valve with a sealed gland connection to an operating handle inside the cabin), but it's still not as absolute a shut off as on the bottle itself.

 

[oldaljones]

Try an electrically controlled solenoid shut-off valve powered by the onboard battery, mounted in the gas locker it worked for me.

Old Al Jones

 

[pvb]

If you want to isolate the gas in the locker, you could fit a solenoid valve. Widely available - here is one supplier.

 

[narooma]

Just to add to the above, the shut of valve fits next to the bottle, the switch will go in the galley. The switch will have a light on when 'live' to remind you to keep it switched off except when in use. You will find it so much easier and safer than having to switch manually at the bottle.

 

[Graham_Wright]

Yes, thanks, I know!

BUT it's still not the same as turning the gas off at the bottle. It is impossible to go "further up the line" than the bottle valve.

Rather than a solenoid, as I mentioned, I could use a ball valve with the shaft through the bulkhead.

BUT, it's still not the same as turning the gas off at the bottle!

 

[pvb]

[ QUOTE ]
BUT, it's still not the same as turning the gas off at the bottle!

[/ QUOTE ]True, but what's the chance of a leak between bottle and solenoid valve anyway? And if the leak is in a separate vented locker, what's the danger?

 

[rogerthebodger]

This may sound mad but I have made some valve motors using a wind screen wiper motor and with a little bit of engineering design this could be the basis for a clamp on motor to turn the gas bottle valve. The motor I used cane from a ford and is reversible by changing the electrical connections.

The extra gear may not be needed with the small valve of a gas cylinder

 

[old_salt]

How about the same devise that is fitted to a Life raft inflation bottle with a pull cord thought a gland in your gas box.
No electrics to cerate a spark.
It only needs to have the right mix and one tiny spark will send the lot up.
I would not have any electrics any where near mine.
I have rigged a valve with a gland so the actuator is outside of the gas box after the bottle / regulator on the LP side with a pull line going all the way to the fore cabin bit like a train emergency pull cord.
Any escapes would be contained in the gas box and directed over board by the drain.
I do take your point about shutting OFF the bottle itself.
My thoughts on the Life raft bottle top are it will turn enough to do what you want it would need some engineering to make it fit the valve on the LPG Plus it would not necessarily turn back on again without going in and doing it manually and then reseting it to shut off, but that should not be too difficult to do. Check one out at your Life raft service depot. I might have a good think about this one myself.
As to an electrical devise it would have to totally encapsulated to give any assurance of it being safe.
The ones from the Calor Marine Shop are for low pressure
Is there such a devise for the HP side screwing directly on to the bottle on the market.
Now thats what we want.

A simple idea would be to make up something like a fore sail wind up drum.
That would fit the valve cap locked with a thumb screw and a guide off the ring handle of the bottle some thing to stop the bottle from turning, a pull cord to wherever. I think job done.

 

[VicS]

[ QUOTE ]
you could fit a solenoid valve. Widely available - here is one supplier

[/ QUOTE ] But are they suitable for use at the bottle pressure or merely for low pressure use downstream of the regulator.

The point about closing the bottle valve is that everything is then shut off, HP connection to the regulator if it is bulkhead mounted as well as the LP system,

An electrically operated valve down stream of the regulator has a high convenience value and a small improvement in safety but is still no substitute for closing the bottle valve.

An electrically operated valve on the HP side of the regulator would be an improvement I suppose on one on the LP system but still leaves a a couple of joints and a hose at full bottle pressure.

 

[lw395]

Some divers use a kind of overgrown speedo cable as an extension for the valve controls on breathing cylinders, known colloquially as 'slob knobs', as they're for the non-gymnasts who can't reach behind their necks whilst kitted up!
Maybe this could be adapted. You could use small uj's or flexible drives to a knob mounted in the baulkhead? I think a key thing would be the 'feel' that tells you the valve has closed properly, as turning it 99% off is of no safety value. In fact, if you include tha valve in your fmea, the only safe thing to do is disconnect the cylinder each time. Which has its own dangers.
Personally, I take the view that you shouldn't have to turn the gas off at the bottle, if you don't trust the installation renew it. I do have the interior valve clearly visible, not stuffed away in a locker though. As for relying on a solenoid in this situation, I'd rather trust the government! And I quite like to be able to make tea without the use of electricity, like if the boat is laid up and the batteries are away being charged.
One could argue that if you leave the gas on at the bottle, a small leak will become apparent because your gas runs out, without ever reaching dangerous levels, whereas if the gas is normally off, only major failures are noticed. Its all nonsense, the only safe way with gas is proper installation and regularly checking condition, imho.
How many of the forum turn their gas main off at home when they finish cooking?

 

[pvb]

The solenoid valves usually sold for boat use, and those included in gas detector auto shut-off kits (Pilot, etc) are all low pressure units. However, the same solenoid valves are made in a huge range of pressure ratings, so it would be quite feasible to use one in the high pressure pipework.

 

[pvb]

[ QUOTE ]
Personally, I take the view that you shouldn't have to turn the gas off at the bottle, if you don't trust the installation renew it. I do have the interior valve clearly visible, not stuffed away in a locker though.

[/ QUOTE ]Glad you said that! I never turn my gas off at the bottle either, but have a valve next to the cooker which I religiously only turn on when I want to use the cooker, and turn it off immediately afterwards. I suspect that we shall be thoroughly castigated by the forum H&S experts for our lax ways! /forums/images/graemlins/wink.gif

 

[old_salt]

Yep I will only use the pull cord as an emergency shut off Exercised occasionally.
My main is the Valve adjacent to the cooker that is opened and closed every time the cooker is used.
As such checked more regularly for leaks ( Virtually every time the area is washed down with soap and water just look for bubbles ) than the emergency shut off valve and easier to replace if ever if suspect.

 

[KINGFISHER 9]

Don't bother with any of those gadgets ..... get out in the rain and turn it off properly ... its the only way to be certain!

 

[vyv_cox]

Yes, I agree. I turn my regulator on in April and, other than replacing empty with full, turn it off in October. Last winter I forgot, so it was on until we returned to the boat in April. After lots of sniffing I lit the gas but no drama at all.

 

[Quandary]

If you have ever seen a boat (or a sailor) after a gas explosion you would turn it off in the locker. Unlike in your house this is the only part of a boat that is vented overboard. Perhaps someone can provide a link to a suitable pic. or clip? Our last one was about 3 years ago, the deck went over the trees.

 

[pvb]

The reality is that there are (thankfully) very few gas explosions on boats. The few that occur, although tragic, are usually caused by simple mistakes in circumstances in which it's highly unlikely the gas would normally have been turned off at the bottle. Many have occurred on liveaboard narrowboats, and I really don't think it's likely that people in that situation are going to turn the gas on and off at the bottle every time they want to use the cooker. Other explosions have happened because crew have accidentally knocked a gas tap on at a time when the bottle would have been turned on anyway - mealtime for instance. Others have happened because flexible connections to cookers have leaked, and the boat either had no shut-off valve next to the cooker, or the crew didn't bother to turn it off. Sadly, many explosions involve elderly boatowners, who perhaps are a bit forgetful at times. I reckon the few gas explosions which happen on boats are accidents which probably aren't preventable - except by banning LPG on boats.

 

[VicS]

Here are a couple of pics.
One is the Lord Trenchard about which you will find an account on the MAIB website but is not the result of failing to turn off the cylinder valve. the skipper was seriously injured

I have no details of the other, happened in Greece or some such foreign place.

Both pictures come from PBO

 

[pvb]

The "Lord Trenchard" MAIB report makes interesting reading - a catalogue of errors.

 

[DaveS]

[ QUOTE ]
I quite like to be able to make tea without the use of electricity, like if the boat is laid up and the batteries are away being charged.

[/ QUOTE ]

The solenoid valve which I have (came with a Pilot gas sensor) has a little lever fitted to it which allows it to be opened without the solenoid operating, i.e. effectively a mechanical over-ride, so if there's no electricity for whatever reason, gas is still available, albeit with one safety device disabled.