Electronics controlled valve for cooking gas bottle? - Page 1
Forum section: electronics / projects

author: Faringdon
author_rank: Super Contributor
timestamp: October 07, 2022, 11:14:02 am
content: Hi,We are designing and building cooking gas bottles with electronics controlled valves. These are for kids camping chalets. Its purely a safety feature because its kids. As you can tell, there is no big market for this product, its just to get these kids out camping.{EDIT...word "kids" used....it wont actually be for use by children whatsoever. END OF EDIT}System description:So we have a bottle of cooking gas with a valve which is opened/closed by a small motor. The valve assembly sits on top of the gas bottle. The kid inserts a token (like coin) into a box, and then they get the gas valve opened for 10 mins, then closed again, until another token is inserted. The token box is near to the valve box and is electronically connected to it via a small cable. Which passes though the enclosure walls.A STM32 micro in the valve assembly contols the valve motor. The micro will be sent to sleep whenever possible. The power to drive the motor comes from a small lithium cell with cell voltage of ~3.6V. There are no SMPS’s in the product. (because we need standby power to be very low). The motor is simply driven directly from the battery. (FET switch, switched by micro). The battery is non-rechargeable, as these have lower leakage current and last longer. The battery voltage is flat at 3.6V for most of its cycle..therefore we cant use battery voltage to sense when the battery is flat. So we intend to do some kind of coulomb counting.Because its gas, the valve assembly product needsATEXapproval.When the motor has fully closed (or fully opened) the valve, we don’t want the motor drawing any power, so I guess we need some mechanical latch in there. We can’t use a latching solenoid valve as they draw too much power in operation and in standby. They draw a high current when first actuated, and the ATEX approval means all our currents need to be well limited.We need to sense when the motor has got to the end position where the valve is fully closed (or fully open)…We are thinking of doing this by sensing the motor current..because when the motor hits the end stop, then its rotor will cease rotation, and thus give no back EMF…so the rotor current will suddenly increase….we will detect this so as to tell us when the motor has reached the end stop...However, we were also thinking of adding a double check to this, by way of a Hall Sensor stuck to the rotor…so we can check the motor really has got to the end stop…after all, the user may somehow yank it so the motor stops in the wrong place (valve not fully open/closed). We are also worried that the user may try and somehow force the valve to be always open (so they can get more gas)Questions, if i may:1..What type of motor do you think can be used for this? (we aren’t finding such low voltage motors for this). Presumably DC motor is a no-no due to brush sparks and the gas (ATEX approval needed)?2..Do you know of any kind of existing product on the market anything like this?…even if its not for cooking gas….…we cant find any.3..Do you have any ideas for low-bias-current current limiters that we will need due to the ATEX approval?4..Why dont normal gas cookers need ATEX approval?..they must have electronics in them.

author: jpanhalt
author_rank: Super Contributor
timestamp: October 07, 2022, 11:41:46 am
content: Have you searched for brushless DC motors? Quite common today. One of my first search hits was for brushless fuel pumps. There are also brushless servo motors.

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 07, 2022, 11:58:11 am
content: Search for "automatic gas valve" or "automated gas valve". No need for a motor since a lot of these use a solenoid.As an example:https://www.aliexpress.com/w/wholesale-automatic-gas-valve.html

author: Berni
author_rank: Super Contributor
timestamp: October 07, 2022, 11:59:40 am
content: The easiest way to get high torque motor out of the box is a RC servo motor.They have plenty of torque to turn a valve and even have the control electronics inside. All you need is to give it a typical 1 to 2ms RC servo pulsetrain from a MCU pin and it will turn to the position you want. If you also want to sense the motor torque then place a shunt resistor in the ground wire to the servo to measure the motor current. The harder the servo is pushing towards the desired axle position the more current it will send trough the motor.This of course works for things like ball valves that only turn 90 degrees. But if you are turning the valve that is directly on the tank (those typically need like 4 to 7 full turns to actually open and close), then you can modify a RC servo for continuous rotation (or buy a servo already built for it). Those can keep turning round and round, however they can no longer be moved to a precise angle anymore, so you would have to watch motor current going up when the valve gets to the end.

author: pardo-bsso
author_rank: Frequent Contributor
timestamp: October 07, 2022, 12:32:02 pm
content: What's the maximum pressure? (I assume this goes before the regulator)Look into any industrial depot, even GNC car onversion shops. That's a very common valve.

author: capt bullshot
author_rank: Super Contributor
timestamp: October 07, 2022, 12:46:48 pm
content: I'd recommend to have a look at the design of gas safety valves, common with all kinds of gas stoves etc. Afaik, these work with a thermocouple and a solenoid, or just plain mechanically. Then try to think which way one can modify the electrical circuit of a thermocouple driven solenoid to add your desired function without breaking the required safety features.IMO designing a completely new gas valve is the wrong way.

author: Faringdon
author_rank: Super Contributor
timestamp: October 07, 2022, 08:50:15 pm
content: QuoteThanks, I wonder if that is why ATEX approval would be needed?...that is, if you dont have the thermocouple to detect no heat (therefore flame gone out and gas potentially spewing out and being an explosion hazard).....is that why ATEX approval would be needed?

author: SmallCog
author_rank: Frequent Contributor
timestamp: October 08, 2022, 10:19:17 am
content: I’d use a quarter turn ball valve (one that’s suitable for gas usage)Drive it into the open position when a token goes in, just before time expires warn the user and if they insert another token leave the valve open, otherwise drive it closed.I don’t know your gas regulations but hopefully using a mechanism like the below to actuate an approved valve satisfies themhttps://www.ebay.com.au/itm/224601175506?mkcid=16&mkevt=1&mkrid=705-154756-20017-0&ssspo=uVJdG9zsT1y&sssrc=2349624&ssuid=fd5nzGNrSmq&var=&widget_ver=artemis&media=COPY] https://www.ebay.com.au/itm/224601175506?mkcid=16&mkevt=1&mkrid=705-154756-20017-0&ssspo=uVJdG9zsT1y&sssrc=2349624&ssuid=fd5nzGNrSmq&var=&widget_ver=artemis&media=COPY

author: capt bullshot
author_rank: Super Contributor
timestamp: October 08, 2022, 10:24:17 am
content: Quote from: Faringdon on October 07, 2022, 08:50:15 pmI can't answer that - I suggest asking an expert (I'm not an expert for ATEX and related stuff). Guessing and asking random people might be fine for marketing purposes, but isn't a recommended way to do safety / certification engineering stuff.

author: jonpaul
author_rank: Super Contributor
timestamp: October 08, 2022, 11:49:18 am
content: Compressed propane gas...electric valve..custom built....consultant...consumers use..Recipe for a liability lawsuitsuggestObtain 1..10M £ liability and EO insuranceretain lawyer spécialiste in consultant liabilities défenseRethinking the job benefits and costJon

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: October 08, 2022, 12:36:38 pm
content: Normally, I avoid preaching safety as most of it is self evident and don't feel a need to stoke my own ego by saving others from themselves. But I digress. Anyway, I've done controls in flammable environments and there are two basic requirements for sensors and safety devices. All circuits must be intrinsically safe (24 VDC or less and 100 mA or less) and all safety devices must be hard wired (no programmable devices in the circuit path). There are exceptions such as certified safety controllers, but you don't have one of those.

author: tggzzz
author_rank: Super Contributor
timestamp: October 08, 2022, 01:02:11 pm
content: Quote from: Faringdon on October 07, 2022, 11:14:02 amFlammable gas + electricity + homebrew electronics + kids + the king of reliable SMPSs.What could possibly go wrong?

author: tggzzz
author_rank: Super Contributor
timestamp: October 08, 2022, 01:05:15 pm
content: Quote from: capt bullshot on October 08, 2022, 10:24:17 amIt is remarkable and noteworthy that needs to be said.I would be amazed (and pleased) if the OP took any notice whatsoever

author: tggzzz
author_rank: Super Contributor
timestamp: October 08, 2022, 01:13:19 pm
content: Quote from: jonpaul on October 08, 2022, 11:49:18 amAgreed.Normally I'm not someone that bothersundulyabout safety (brought up a kid with a 6ft vertical hole in the kitchen, backpacked together around India in early teens, solo pilot making forced landings before able to start to learn to drive a car, etc). I certainly hate ambulance chasing lawsuits, especially where the victim wasn't paying attention or doing something silly such as walking into the road looking at their phone.But in a case where there would have been planned negligence by someone with Dunning-Kruger syndrome,I would definitely use a good lawyer and the legal system to itsfullestextent.It wouldn't bother me if the perpetrator was "a man of straw" and not able to provide restitution; sometimes visible punishment is necessary pour encourager les autres.(Other example: an idiot with a laser blinding an innocent person passing by)

author: Terry Bites
author_rank: Super Contributor
timestamp: October 08, 2022, 01:44:58 pm
content: Sparks gas sparks gas sparks gas. mmmmm. Kids at camp whoa!Are you "gas safe" registered and do you infinite personal liabilty insurance and afford best lawer in the land? [no, not your cousin]Don't even think about it.Its illegal to fit one yourself even if you buy a ready made electric valve system off the shelf.Permitting or encouraging a an unregistered person to work on gas is also a crime in the UK.Grieving parents can be a real pain and you're too young to do years of jail time. You probaly won't get do do the time though, the parents will string you up first.Believe!!

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 08, 2022, 01:45:55 pm
content: Quote from: Faringdon on October 07, 2022, 11:14:02 amAt least they (OP used "We") are aware about safetyAnd fortunately they are designing and building the complete thing, gas bottles and all, so it must be okIn itself it is not to dangerous when an approved "automated valve" is used and the installation is done by a professional gas fitter. Risk on leaks should then be minimal and an approved "automated valve" should be guarded from making sparks. As long as the electronics is not in the same enclosure as the gas bottle and the wires are fed through a proper guide the risk will be minimal.But still be very aware of any liability. And like tggzzz pointed out, to us, here on the forum, your (Faringdon) reputation is not one of being very capable.

author: AndyBeez
author_rank: Frequent Contributor
timestamp: October 08, 2022, 02:13:17 pm
content: I'm not sure of the 'code' in your locale, but my 50 centrinos...Your design MUST be failsafe off - if the power fails or the STM32 crashes, the valve shuts both automatically and mechanically. There must never be a latching action.Your design must be tamper proof; say some 'bright spark' kid realises the gas can be left on by removing the battery, which would have been me at that age? Maybe all parts should be kept in a locked cage?Your design should not be activated by interference from any other EM field - such as wifi, mobile phone or even CB radio. Metalic shielding of the uC is needed.Your design should be safe in storage - there should be no egres of gas from the valve if the mechanism if unused for months. The battery should also have enough capacity to remain unattended for long periods.Your design will need to be both certifiable and insurable.+ Why bother with a token and the token's mechanism when you could use an app over Bluetooth? It's what 'kids' expect these days.

author: geggi1
author_rank: Frequent Contributor
timestamp: October 08, 2022, 02:53:12 pm
content: I'm enough familiar with ATEC and IECex to probably give you some sensible advice.First. of all it is going to be expensive.Second. you would be able to build this with off the shelf components.Third. get familiar with the IEC 60079 series of regulations.Fourth. If you decide to build its probably best to use Exd components.

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 08, 2022, 03:56:38 pm
content: Unless the cooking process needs an open flame, how about use an induction cooker instead?

author: tooki
author_rank: Super Contributor
timestamp: October 08, 2022, 05:07:19 pm
content: OP said it’s for a kids campground. Shouldn’t they be cooking on campfires?

author: floobydust
author_rank: Super Contributor
timestamp: October 08, 2022, 07:17:20 pm
content: Who charges kids by the 10 minute interval for cooking while camping? The premise seems ridiculous, just buy your own bottle.OP, you're in way over your head again and the cute story about it being for "kids" seems to be a larp.A lot depends on how many BTU the burner is. There's a pressure regulator, usually redundant dual shutoff solenoids for safety according to gas standards. The electronics has a functional safety requirement for the hardware and firmware as well. You've said nothing about the ignition system and flame detect, where it's being used etc.You need to meet the gas safety codes as well as hazloc, a professional engineer assesses the hazardous area and classifies accordingly. Not to your economical whim.

author: Faringdon
author_rank: Super Contributor
timestamp: October 08, 2022, 08:24:19 pm
content: Thanks for all these, i will look into all this....BTW, it will need to be "generally safe"....the people who use this will get a demo of how to use it safely....they are trained people.......it will likely also have manual turn on/off valves aswell, and when these are used properly its perfectly safe...There wont be any lawsuits. Thats all i can say. This just needs to be designed to be safe to "people behaving sensibly with the kit"....and...."people who use it in accordance with the instructions".

author: jonpaul
author_rank: Super Contributor
timestamp: October 08, 2022, 08:48:44 pm
content: thought experimentsValve or control fail ON, uncontrolled gasGas on, flame outChild is burned by stoveWe consulted on surgical lasers, illuminators MRI,We insisted that our Customers signed a liability / hold harmless agreement before acceptce of order.jon

author: exmadscientist
author_rank: Frequent Contributor
timestamp: October 08, 2022, 10:27:39 pm
content: Screw this one up badly enough and you get a nice explosion.QuoteQuoteQuoteQuoteQuoteQuoteQuoteQuoteQuoteQuoteQuoteQuoteQuotePlease stop. Please. Just. Stop. I'm aware of your reputation but I'm going to say this anyway, "pour encourager les autres".Do you know what "foreseeable misuse" is? Because this has a "foreseeable misuse" disaster lawsuit written all over it. When your device fucks up and starts spewing fuel into the air randomly because of a foreseeable mistake, and somehow it ignites (or even doesn't, it doesn't really matter),no one is going to touch that manual shutoff. They are going torun away. I know because I've been around "small" propane tank fires. You have no idea what you are doing or how many people you could kill (though it's decent odds you do know how many people you can troll).Just stop this insanity now.

author: gbaddeley
author_rank: Regular Contributor
timestamp: October 08, 2022, 10:48:42 pm
content: All token & coin & free timer based cooking facilities that I have seen are electric. Eg public hot plates / BBQs in parks and camp grounds, even if gas is in nearby buildings for hot water etc. The reason is SAFETY. Gas is very dangerous if anything goes wrong with the token system or valves, hoses, burners.

author: Faringdon
author_rank: Super Contributor
timestamp: October 08, 2022, 11:25:28 pm
content: Thanks,So valves like the following, are not safe?https://tameson.co.uk/valves/solenoid-valve/2-way/brass/st-sa012b105f-012dc-solenoid-valve-2way-012inch-brass-0p0-10bar-fkm.html?gclid=CjwKCAjwv4SaBhBPEiwA9YzZvBG6DHbw-JnyXmShK8lvi3Y8Jaf_hfnEAfrV4Gr6Z4WBcXtsvXoGwxoCkEMQAvD_BwEThere's no such thing as a safe electronic valve for cooking gas?May i ask, just so i can gauge the responses here.....what do you think of the safety of the following cooking gas situation?...Quote...Thanks....And so lastly, please may i ask...What should people do if they cant afford to buy a gas bottle all for themselves?...and the only way they can get cooking gas is to buy a "metered cylinder", so to speak. (as described here), .Should they just not eat cooked food?Thats not easy when all you can afford is rice.....and other foods that need cooking....Also, what about the millions in Ukraine at the moment, who have no cooking facility, or facility to boil water to clean it.....they cant afford a full gas bottle all for themselves....They dont have electricity or batteries for electric cooking.Should they just go hungry?QuoteThe "metered gas cylinder" will only be used in designated "communal areas", where there are multiple people around who can recognise and deal with a gas leak.

author: tggzzz
author_rank: Super Contributor
timestamp: October 09, 2022, 12:08:48 am
content: Quote from: Faringdon on October 08, 2022, 11:25:28 pmOh FFS. Are you deliberately being thick or are you trolling?Which bit of "nobody here is qualified to give you a correct answer" do you not understand? Thedevilwill be in thedetailsthat we cannot see/assess.It is a case of "those thatarequalified know enough tonotanswer, those thatdoansweraren'tqualified".QuoteAnd how, exactly, do you guarantee suitable people will be there at every instant, and they will in all circumstances correctly recodnise and correctly deal with it?Wishful thinking is not acceptable where serious injury is a possibilityIf someone here says "go ahead and do what you plan because it will all be OK", based on that assurance and encouragement would you feel able to proceed?What's your endgame for this nonsense? You seem to have a habit of, when you don't like the answers, merely repeating the question until you get the answer you like. That's characterisic of politics or religion, not engineering.

author: fourfathom
author_rank: Super Contributor
timestamp: October 09, 2022, 12:09:38 am
content: We use electric solenoid valves like this on boats:https://www.defender.com/product3.jsp?name=fireboy-xintex-lpg-propane-gas-solenoid-valve&path=-1|2276204|2276252|2276260&id=122213These are for the low-pressure side of the regulator. I don't know about the regulatory requirements, but marine regs are pretty strict.

author: floobydust
author_rank: Super Contributor
timestamp: October 09, 2022, 12:15:34 am
content: Safety codes distinguish between indoor and outdoor use, permanent or temporary installation, the burner size, type of pilot etc.You are in love with and trying to rationalize the indoor stove used with a portable outdoor tank and regulator. The hose and other fittings/adapters are unknown source and look like Benny Hill Co. is the supplier. If only the oven was closer to the tank lol. This is propane on a methane appliance? You want to go with this solution on a corporate level"... multiple people around who can recognize and deal with a gas leak." So do they leap into the flames and be part of the cooking?WTF is wrong with you, nobody can "deal with" a gas fire. Reaching the shutoff valve is not always an option when there's a flaming leak.Gas codes here want the regulator to vent in a safe manner, in the case the diaphragm ruptures a regulator will spew out gas. One big reason household regulators are now located outdoors, and commercial buildings have the vent piped to the roof.

author: tggzzz
author_rank: Super Contributor
timestamp: October 09, 2022, 12:42:20 am
content: Quote from: floobydust on October 09, 2022, 12:15:34 amPrediction: treez/faringdon won't like that sensible answer. He will ignore it and ask a trivially different question in the hope that he will get an answer he likes!

author: Faringdon
author_rank: Super Contributor
timestamp: October 09, 2022, 12:50:33 am
content: OK thanks...what we want, is like this.....https://www.paygoenergy.co/cylinder-smart-meter-interactive#product-info..it uses an electronic means to shut off the gas when the cust runs out of money...ours custs dont have mobile phones, so we want it like the above , but with tokens.Thing is, we cant find the electronic valves off the shelf that work with LVDC, and that latch (ie, they would draw down the battery holding the valve open).So what we want, is a Pay as you go gas cylinder...rather in the same vain as the above. As you can see, the valve needs to be electronically operated. Unless we can do some kind of mechanical timer arrangement.......Fourfathom kindly shows a good solonoid gas valve in #27...though , like all others on the market, it needs constant current flow to keep it open...and that would run down our battery too quick.

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 09, 2022, 05:15:09 am
content: A way simpler solution. Use smaller gas bottles made for the job of camping.https://www.campingaz.co.uk/No need to invent something new. Sure no money for you, but also no lawsuits.

author: mzzj
author_rank: Super Contributor
timestamp: October 09, 2022, 06:07:24 am
content: Quote from: pcprogrammer on October 09, 2022, 05:15:09 amThese are very expensive scam to get poor peoples money. They are even not 100% full when sold!How can I fill these from large 33kg 100% propane cylinder so that they get completely full?Should be safe since they are designed for gas use correct?/end of treez mode

author: jonpaul
author_rank: Super Contributor
timestamp: October 09, 2022, 06:25:51 am
content: UK has had mechanical coin or token gas meters on fireplace gas logs and elsewhere since 1920 (?)A simple coin slot and clockwork mechanism10 min....10 pence (?)We saw them still in service in London hôtels and flats in 1970.No electricity, less risk, cheap and simpleJon

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 09, 2022, 06:28:36 am
content: Quote from: mzzj on October 09, 2022, 06:07:24 amHappy to biteSo yours is no scam then? You are doing it for free to help the poor and needy?Filling needs to be done by qualified personnel at a filling station, otherwise the lawsuits come back in.And yes these things are safe when properly used. They have been around very long to build up a solid track record.

author: tggzzz
author_rank: Super Contributor
timestamp: October 09, 2022, 08:11:33 am
content: Quote from: mzzj on October 09, 2022, 06:07:24 amTee heeThat would have been a good troll, but then you added the final line!

author: Faringdon
author_rank: Super Contributor
timestamp: October 09, 2022, 10:10:57 am
content: QuoteThanks, Yes thats correct.Think eg of all 3rd worlders, and of course, not forgetting Ukraine where they are unfortunately taking regular missile strikes outaging their gas/elec services etc.As from earlier, this PAYG product does what we want, but from mobile phone......we need it from tokens and internal battery (battery will get taken in for changing every now and then)https://www.paygoenergy.co/cylinder-smart-meter-interactive#product-infoQuoteThanks, this would be fantastic though we struggle to find details of itQuoteThanks but those leisure BBQ things are for just that.....you cant use them long term for millions of people who use them daily as the waste gets way too much.

author: MK14
author_rank: Super Contributor
timestamp: October 09, 2022, 11:02:03 am
content: Why not ditch the electronics and that design concept, entirely.Have a purely mechanical system, with a hand operated, gas-valve/tap, similar to normal/current ones. But it needs the insertion of the right token type to initially release the valve (allow it to turn) and/or it turns freely (like pedaling backwards on a bicycle), until a token is inserted.It then has a mechanical gas flow thing in its pipe (like they have in gas meters), which (mechanically), gradually turns that gas valve back off again (N.B. For safety reasons, needs to be an On/Off type (by suitable mechanical design) of valve/switch control, to avoid risk of low levels of gas, continuing to seep out, as it runs out of tokens), after the appropriate amount of gas is used.That should be able to be designed/constructed in such a way, that it can be (intrinsically) safe. Then no electronics to malfunction, or spark/over-heat/short-out, no problematic battery issues and possibly cause a safety risk.EDIT: I think this particular forum (Electronics), is completely unsuitable/unsafe for discussing safety gas stuff like this.

author: capt bullshot
author_rank: Super Contributor
timestamp: October 09, 2022, 11:17:38 am
content: Quote from: Faringdon on October 09, 2022, 10:10:57 amWow, what an unethical product this is - helping rich providers of gas to draw money in smaller portions from poor people and marketing it as an "revenue generator". I don't think that helps the poor people at all, just increases the revenue of the supplier. In the end, the customer pays the gas plus the apparatus to cut him off from the gas supply - no one will give out that product for free to the potential customers, its cost will be hidden in the gas cost - WTF!

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 09, 2022, 11:53:47 am
content: There is a bit of a contradiction in this picture.The original poster needs a system to control gas supply to a cooking appliance where KIDS on a campground can cook for themselves. This, to me, seems to be something that needs supervision of an ADULT, and in this case the adult can easily control the time spend on the cooking appliance. (Depends a bit on the kids age of course, but still)Sounds indeed more like a money making scheme of some campground owner, instead of really caring about the underprivileged youth.

author: capt bullshot
author_rank: Super Contributor
timestamp: October 09, 2022, 12:04:39 pm
content: Quote from: pcprogrammer on October 09, 2022, 11:53:47 amCorrect, my critic was about the linked PAYG product, not Treez' product idea.

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 09, 2022, 12:15:19 pm
content: Quote from: capt bullshot on October 09, 2022, 12:04:39 pmMine was not in response of your post, but a general observation based on "Trees"\"Faringdon" posts.But the critic on the PAYG product is deserved for sure. But unfortunately it is how it works in this world.

author: Faringdon
author_rank: Super Contributor
timestamp: October 09, 2022, 01:44:41 pm
content: I dont think eg the Ukrainians will have to pay for the tokens...but they will be kind of rationed to them, so that they dont use more gas than they need.Any better ways of getting cooking ability to eg millions of Ukrainian bomb shelter dwellers much appreciated?

author: Faringdon
author_rank: Super Contributor
timestamp: October 09, 2022, 01:46:57 pm
content: QuoteThanks, if your "pure mechanical" idea is possible, then yes, ...but i have doubts its possible like that...and it needs electronics circuitry. AYK, Gas engineer forums wont know about electronics.

author: MK14
author_rank: Super Contributor
timestamp: October 09, 2022, 02:49:07 pm
content: Quote from: Faringdon on October 09, 2022, 01:44:41 pmQuote from: Faringdon on October 09, 2022, 01:46:57 pmA safe/quality gas engineering source, should be able to mention/specify any electronic parts/systems (even if they can't design it at a component level), at a high block level, if strictly safe/necessary. But I suspect electronics is undesirable and rather tricky to make safe. Especially with a latching (no further electric power needed), capable unit.I.e. safe solutions, seem to always be continuously electrically powered (or self powered, e.g. via thermocoupling to the gas pilot/flame?). Presumably, as something which needs to be continuously powered to energise it (keep the gas flowing), will tend to STOP the gas flow, when power is lost, and/or other fault conditions. Which could be part of its safety design considerations.There are other possible safety issues, with such equipment, in bomb shelters. Such as Carbon Monoxide gas buildup (highly poisonous), in a relatively confined space. Fire hazards in a relatively confined space, which could be difficult to exit, in an emergency.Also risk of explosions, if the gas canister gets caught up in an external fire and/or is bomb damaged.I.e. If you think where you are, might get bombed. You don't want to be sitting near a pile of Propane (or whatever) gas cylinders. Which could turn a minor bomb hit, into a much bigger/worse fire/explosion.Maybe, better solutions. Would be to cook the food beforehand, elsewhere and then self-tin/can/bottle it (ideally following food safety rules). Then consume that food (which could also include supermarket tins). Cold, if necessary.Is it possible to have an above ground, small petrol/diesel generator (very risky to have in the bomb shelter, itself. Because of the risk of Carbon Monoxide poisoning, in confined spaces). Then run a 'mains' cable down into the bomb shelter?Would probably need lower power rating cooking appliances (assuming a small generator). But slow cookers, are something like 60watts, and rather small microwaves, can be fairly low (not sure without checking, but perhaps 400 watts).There are mini-cooking devices for cars, which operate at 12 volts. Maybe those could be powered by a heavy-duty lead acid battery. You can then make a cup of boiling water, suitable for making instant soups, coffee, hot-chocolate etc. Nice, if that is the only hot food you can get, in the middle of winter.My later solutions, are NOT 100% brillient (food wise), especially compared to 'normal' eating circumstances. But we are talking about a (hopefully) very, very rare indeed war (emergency) situation. 'Beggars can't be choosers'.Actually, why not fill some thermos's with boiling water (BEFORE) the bombing air-raid warning. Then take those to the bomb shelter, and use the very hot water, to make warmer/hot soups/coffee, hot instant mash (potatoes), etc.E.g. Use a machine, which keeps itself full of boiling water all the time (Hot Water Urn, plugged in, in a non-bomb-shelter kitchen). Then if and when an air-raid occurs, fill the thermos's with (near) boiling water. To improvise some kind of hot meal preparations/capabilities. Without any further need for gas/electricity.

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 09, 2022, 03:45:48 pm
content: If you are really serious about this then look into the following.Search for "gas safety valve for a gas bottle"Search for "motorized gas valve"A safety valve to cut of the gas in case of a hose rupture:https://www.bcf.com.au/p/grillman-gas-safety-valve/609303.htmlTo control a ball type gas valve:https://nl.aliexpress.com/item/32990192156.htmlorhttps://nl.aliexpress.com/item/32958696514.htmlGet yourself some of these motorized valves and see how they work or check out their specifications. Do the proverbial leg work for it. It is not that hard. Or even do real leg work. Go out to a specialized store and see what is available.A proper stove top will have safety features like MK14 wrote about. For you it is just looking into the safety regulations surrounding the coupling to the gas bottle. Like for instance INOX armored hoses, that last a life time.

author: AndyBeez
author_rank: Frequent Contributor
timestamp: October 09, 2022, 05:49:52 pm
content: Quote from: MK14 on October 09, 2022, 02:49:07 pmEvery year people die at music festivals - or glamping - or both - from CO poisoning after they misuse gas stoves inside their zipped up fabric tents. And then there are those who kill themselves running the car engine in a garage*. So RESPECT the risk from Carbon Monoxide poisoning. Now go add a CO alarm to your bill of materials.https://www.nhs.uk/conditions/carbon-monoxide-poisoning/* Not applicable to EV drivers.

author: jonpaul
author_rank: Super Contributor
timestamp: October 09, 2022, 09:07:12 pm
content: key design wordsfail safeworst caseidiot proofOnce again our favorite trool suceeds in wasting our timeBravo!Jon

author: floobydust
author_rank: Super Contributor
timestamp: October 10, 2022, 01:21:24 am
content: Well, think of the starving children.How will they learn about E.Coli in their hamburgers because they ran out of tokens

author: Faringdon
author_rank: Super Contributor
timestamp: October 10, 2022, 05:14:09 am
content: Thanks,Also, a gas cooker needs (and permits) a spark to be used to light it.As such, how can it possibly ever pass ATEX approval?Do you agree, ATEX approval and gas fires can never happen?

author: james_s
author_rank: Super Contributor
timestamp: October 10, 2022, 06:07:00 am
content: Every RV (caravan) or marine store should have suitable valves on the shelf. They're used to control the propane from a panel inside the RV/boat.

author: tggzzz
author_rank: Super Contributor
timestamp: October 10, 2022, 08:01:19 am
content: Quote from: Faringdon on October 10, 2022, 05:14:09 amLooks like the prediction I made in reply #29 is coming true.https://www.eevblog.com/forum/projects/electronics-controlled-valve-for-cooking-gas-bottle/msg4454536/#msg4454536

author: LaserSteve
author_rank: Super Contributor
timestamp: October 10, 2022, 03:38:43 pm
content: Boy Scouts / Scouts USA requires twoadults present for the use of Propanefor very good reasons. I've seen what happenswhen unsupervised Scouts toss a tiny disposablePropane tank onto a very large campfire.The thirty foot trail of large glowing embers landedprecisely over the two rows of summer camp issuedcanvas tents.I was the Senior Patrol Leader at anearby campsite. I was wondering who broughta grenade to summer camp when I heard the blast.I was first on the scene, there were no cell phonesback then and I didn't have a car. No one was seriously hurtThe embers glowing on the tents was spectacular. Help was two miles away if needed.Woe betide the camp counselor who allowedthat to happen, it was a provisional unit, Madeup of Scouts whose Units were not attendingCamp. A few from here, a few from there. Next guyon Scene was the Camp Chaplain, so this was notgetting "Hushed under the Rug, or Leaves" so to speak.Children plus compressed gas do not mix well.So I'm curious. Is this silly, idiotic, concept going into a confined space? Fuel Air explosions cause a gruesome death, either by slow suffocation, infection from burns,or unrepairableshockwave damage to internal organs.No, No, No, No. One kid with a screwdriver or vise-gripswanting to bypass your controller for a hot Coco or popcorn, and you have a problem.I wish I could introduce you to my childhood friend Tom.He's no longer with us after a FAE refueling a lawnmower.Oh, he survived for a few years, but the rejection and cruelwords over his skin grafts by teenage girls did him in.Had a heart of gold.No, just don't. Gas requires adults.This from a fellow who was quite the teenage experimentor.My employer, a university, has went out of it's way to eliminate flammable gas burners in labs. For the only thing worse then a child is a distracted graduate student.These lessons are learned in blood.Steve

author: floobydust
author_rank: Super Contributor
timestamp: October 10, 2022, 04:18:47 pm
content: Quote from: LaserSteve on October 10, 2022, 03:38:43 pmDon't bother you can't dig in - we are always fed vague, fictional requirements.Quote from: tggzzz on October 10, 2022, 08:01:19 amHey you've figured out the troll algorithm. Find any way to rationalize seeing only what you want.I worked under a CEO like this, he tried very hard to rationalize that no safety standards applied to a combustion product using natural gas. It caused great hardship for the engineering dept. as he is the top boss yet a few people would not go along with it, including myself.It is caused by low intellect, no conscience and no patience to research, design and build a safe product that would pass approvals, he just wanted profit ASAP and someone else to be the fall guy for any legal reasons.I kept his document debating why the product needed safety approvals, which included customer perceptions and costs vs. profits if an explosion occurs. He deleted the doc off the server and I copied it back over lol. It's good reading into the mind of a psychopath trying to justify what they want, whereas the rest of humanity uses common sense.I've never seen micro-power gas valves, latching ones included. Smallest is RV propane refrigerators (12VDC and ~1W) and IR remote-control gas fireplaces that have no mains power (only mV thermopiles) it was a 4xAA 6V system for flame control.

author: Faringdon
author_rank: Super Contributor
timestamp: October 10, 2022, 04:33:52 pm
content: Thanks, these are great replies...i am going though and through them.......i am seeking that "proof" that this project (in whatever manifestation) is a "no-go" project now, as all are very negative towards it.We wont do it, if the benefits are destroyed by the lack of safety.We wouldnt use something if we wouldnt use it ourselves.I am reading your kind replies to separate out what hazards are particular to just our system, and those hazards that are also particular to existing gas cooking solutions which do meet approvals.The "idea" is a good one.Eg, Getting cooking possibility to the bombed out people of Ukraine.It unfortunately does need some kind of token rationing.And does need not to be mains connected, as power sources are scarce.It also has to be borne in mind, just what the Ukrainians will do with gas cannisters...if no-one helps them at all with any solution......they may well do something even more dangerous than the system we suggest here.If i was in a Ukrainian bomb shelter, i would like the system of this post...but would also like a manual valve also inline with the electronic one.....so i could manually shut off the gas when finished cooking.Also would like thermocouple flame fail detect....so will need some InAmp circuitBTW, we have wrote to many companies asking for a valve like ours. (Low voltage, no current draw after actuated)The following ones, have very quickly just come back with a "No".......BESSolenoid-valves.comHamilton Gas productsEPH controlsSo it looks like at the very least, we are looking at a custom valve here.

author: tggzzz
author_rank: Super Contributor
timestamp: October 10, 2022, 04:43:01 pm
content: Quote from: Faringdon on October 10, 2022, 04:33:52 pmWhy on earth are you seeking proof? Is it just a troll-like technique to keep people wasting their time by responding?Just drop it.

author: Brianf
author_rank: Regular Contributor
timestamp: October 10, 2022, 06:25:12 pm
content: Quote from: Faringdon on October 07, 2022, 11:14:02 amIf you are aiming for ATEX certification then don't forget to budget somewhere around £20k-£30k to get it. ATEX certification requires the use of an approved third-party ATEX test house, it's most certainly not something you do yourself.

author: fourfathom
author_rank: Super Contributor
timestamp: October 10, 2022, 10:53:08 pm
content: Quote from: Faringdon on October 10, 2022, 04:33:52 pmIn one of the first posts here pcprogrammer linked to a bunch of motor-driven ball-valves:https://www.eevblog.com/forum/projects/electronics-controlled-valve-for-cooking-gas-bottle/msg4451872/#msg4451872These shouldn't need power after actuating.BTW, I'm not saying that any of this is or isn't a good idea.

author: Gyro
author_rank: Super Contributor
timestamp: October 11, 2022, 09:02:35 am
content: I still don't get how the narative has changed from "These are for kids camping chalets" to Ukranian bomb sheltersIt sounds as if some fundamental project parameters need tying down before proceeding anywhere!

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 11, 2022, 09:05:16 am
content: Quote from: Gyro on October 11, 2022, 09:02:35 amIs it just more proof for trolling

author: joeqsmith
author_rank: Super Contributor
timestamp: October 11, 2022, 11:19:25 am
content: I've seen remote bottle openers like this:https://www.nitrousexpress.com/automatic-remote-bottle-opener-11107.aspI use their solenoids.https://www.nitrousexpress.com/nitrous-and-fuel-solenoids/There are many OTS gas valves available for all sorts of applications.

author: LaserSteve
author_rank: Super Contributor
timestamp: October 11, 2022, 01:41:07 pm
content: Stop feeding this troll. That seems to be the best course of action.Steve

author: TomS_
author_rank: Frequent Contributor
timestamp: October 11, 2022, 02:03:24 pm
content: Quote from: Faringdon on October 08, 2022, 08:24:19 pmAnd yet here we are with RCDs because people used hair dryers in the bath tub, and warning labels on bottles of bleach that you shouldn't drink it.If you honestly think that the general population can be trusted to be sensible then you are asking for that lawsuit...But I dont see why this needs a "new" solution. Coin operated BBQs are a thing already, and have probably undergone all of the required safety checks/tests/certifications. As much as I like to build something from scratch, I would save myself the trouble in this instance and buy a commercial product. At least there would be someone to blame other than myself if something goes wrong.

author: MK14
author_rank: Super Contributor
timestamp: October 11, 2022, 02:27:45 pm
content: There seems to be a similar, but ended up different (in that there is no mention of Ukraine, that I can see), here:https://www.electro-tech-online.com/threads/cooking-gas-bottle-valve-controlled-electronically.164000/Apparently (presumably) by the same Author/OP.They (the other people, on the other forum), also took the time and effort, to carefully explain that the gas might be leaking a bit, and the slightest spark (e.g. from electronics), could cause an explosion. But, instead of accepting (presumably) (semi-)expert opinion, they (OP) go, yada yada yackidi yack, what if blar blar blar, and ignore the point entirely, and (I don't know what they are thinking, so I'm guessing, here) seem to suggest the safety gas regulations should/can be ignored (is the gist of it, I seem to get, from a very quick read though of it).The idea of safety rules and regulations, is to attempt to make things safe, even if the person is a clueless uneducated, somewhat reckless, individual, with poor common sense.But unfortunately, there are always those people, who ignore safety (and other) regulations. So, they shouldn't touch many things, including gas equipment/design, with a very long barge pole.Quote

author: LaserSteve
author_rank: Super Contributor
timestamp: October 11, 2022, 03:53:38 pm
content: Attached is a pic of a unit that was approved for the job. Meets all the international requirements etc.No batteries, and obviously only affordable in large scale use. Might have a little issue finding Shillings that were not melted for scrap value. Incredibly reliable and safe when properly installed.After the Ukrainian Farmers bypass this unit, I'm sure they Will have a photo of an APC, probably a BMP-2, filled with coin operated gas meters going to the scrap yard. Towed by a mighty John Deer..

author: Terry Bites
author_rank: Super Contributor
timestamp: October 11, 2022, 04:59:55 pm
content: Ah yes, the royal we.

author: Faringdon
author_rank: Super Contributor
timestamp: October 11, 2022, 05:21:51 pm
content: QuoteThanks, AYK, there do exist electronic gas valves, which pass regulations, and exist on equipment which passes regs, this is what prevents us from binning the idea.

author: MK14
author_rank: Super Contributor
timestamp: October 11, 2022, 05:47:37 pm
content: Quote from: Faringdon on October 11, 2022, 05:21:51 pmDid you try, this company:https://www.tlxtech.com/solutions/operation/latching

author: tggzzz
author_rank: Super Contributor
timestamp: October 11, 2022, 07:27:20 pm
content: Quote from: LaserSteve on October 11, 2022, 01:41:07 pmI never like jumping to that conclusion. I prefer to attribute such behaviour to stupidity/perversity rather than malice.Nevertheless, sometimes stupidity or perversity are not a sufficient explanation

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 12, 2022, 05:14:05 am
content: It would be interesting though to know what is really behind this all. Is it indeed a simpleton trying to make a living or someone with a perverse intelligence pulling us into responding to his silly questions? And how, if the latter is the case, does that provide fulfillment for him?And for sure Faringdon has asked some silly ones, like the thief ability of scopes or the wetting my floor to avoid static dischargeCan't speak for others, but I have fun in participating

author: tggzzz
author_rank: Super Contributor
timestamp: October 12, 2022, 09:35:54 am
content: Quote from: pcprogrammer on October 12, 2022, 05:14:05 amThere are other, somewhat sadder, possible explanations.QuoteI remember the former (which has some vague plausibility until considered in more detail), but I must have missed the latter!QuoteIffthat's understood then it isn't a waste of your time.

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 12, 2022, 09:44:18 am
content: Quote from: tggzzz on October 12, 2022, 09:35:54 amhttps://www.eevblog.com/forum/manufacture/spraying-wooden-floor-with-water-to-reduce-esd-damage/Quote from: tggzzz on October 12, 2022, 09:35:54 amThat is the beauty of retirement, got all the time in the world

author: tggzzz
author_rank: Super Contributor
timestamp: October 12, 2022, 10:01:33 am
content: Quote from: pcprogrammer on October 12, 2022, 09:44:18 amOh, that oneisreally quite "special"! It clearly heightens the troll-vs-idiot-vs-X question.QuoteNot so. Your micromorts are increasing all the time.https://en.wikipedia.org/wiki/MicromortWhich means it is increasingly rational to take more risks in the pursuit of fun

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 12, 2022, 10:10:41 am
content: Quote from: tggzzz on October 12, 2022, 10:01:33 amDid not see laughing behind a computer mentioned as a micromort risk

author: tggzzz
author_rank: Super Contributor
timestamp: October 12, 2022, 10:17:51 am
content: Quote from: pcprogrammer on October 12, 2022, 10:10:41 amI like the concept of micromorts (and the associated microlifehttps://en.wikipedia.org/wiki/Microlife) since, in a very understandable and useful way, they cut through a lot of crap about safety/danger.Spiegelhalter is one of the people I always listen to; he is good value for my time.BTW: my edit and your posts crossed in the æther by 3s. I emphasised my point with "...means it isincreasinglyrational..."

author: Gyro
author_rank: Super Contributor
timestamp: October 12, 2022, 10:40:54 am
content: Quote from: tggzzz on October 12, 2022, 10:17:51 amRight, that's the last time I do more than 20 mins of moderate exercise! (having just got back from an hour at the gym with our PT, who specialises in those of us who are 'getting on a bit'). 1 measly microlife for an extra 40 mins of toil and sweat!

author: tggzzz
author_rank: Super Contributor
timestamp: October 12, 2022, 10:49:58 am
content: Quote from: Gyro on October 12, 2022, 10:40:54 amThat's anegativereturn: 30 mins gain for 40 mins spentHowever, the microlifes are cumulative, whereas micromorts aren't. That ought to skew my "calculation" above.Nonetheless, it is worth considering QALY. Would you prefer to drop dead exercising or have your body slowly decay in different and unpleasant ways? No simple answer to that question

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 12, 2022, 10:51:36 am
content: Quote from: tggzzz on October 12, 2022, 10:17:51 amI have never been to worried about death. If it comes it comes. But I do live healthier now. Way less sugar and a brisk walk every day. Never smoked and stopped with alcohol 10 years ago. Not that I drunk much, basically only at parties and dinners, and got drunk easily, which made me feel bad on the morning after, so decided no more.And when I have to do a job that brings risk I evaluate on safety and take measures accordingly.

author: Gyro
author_rank: Super Contributor
timestamp: October 12, 2022, 11:48:54 am
content: Quote from: tggzzz on October 12, 2022, 10:49:58 amDrop dead, no question!

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 12, 2022, 11:56:21 am
content: Quote from: Gyro on October 12, 2022, 11:48:54 amHaving seen slow decay of both body and mind, that for me is the answer too.Don't know how it is in England, but in the Netherlands there is now an organization having a lawsuit about euthanasia and your right to get it. Hopefully it will become easier all over the world to get it done when you want it.

author: tggzzz
author_rank: Super Contributor
timestamp: October 12, 2022, 12:34:44 pm
content: Quote from: pcprogrammer on October 12, 2022, 11:56:21 amIN the UK there are the occasional challenges to the status quo, and even some lawsuits. All have failed, and it is stil lillegal to assist suicide -b ut enforcement is becoming less universal and less enthusiastic.People do travel to Dignitas, with helpers.Ought to ask the OP what the expected micromort values for his various dreams/nightmares are (or are considered acceptable).

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 12, 2022, 12:49:03 pm
content: Quote from: tggzzz on October 12, 2022, 12:34:44 pmProbably zero, because he is very concerned with the safety of thechildrenUkrainian citizens.

author: Gyro
author_rank: Super Contributor
timestamp: October 12, 2022, 01:10:27 pm
content: I remember watching Terry Pratchett's documentary on Dignitas (when he was first diagnosed with Alzheimer's). I was shocked - the end looked anything but drop-dead or painless!'Drink this anti-emetic, wait a while. Now, last chance, drink this solution, you'll feel very thirsty but try not to drink'. The guy looked really distressed as he went.

author: tggzzz
author_rank: Super Contributor
timestamp: October 12, 2022, 01:18:32 pm
content: Quote from: pcprogrammer on October 12, 2022, 12:49:03 pmThe micromorts can't be zero, even though they might be dwarfed by those of Ukranian citizens.

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 12, 2022, 01:19:10 pm
content: Quote from: Gyro on October 12, 2022, 01:10:27 pmA proper euthanasia is painless but not instant, yet close enough. Both my parents are euthanized and I was there for both. They where first put to sleep with what is used for operations and when out cold, the agent that does the killing is injected. The heart stops soon after, and you slip away into eternity. Nothing scary at all.Much better then jumping in front of a train or of a building and bother unsuspecting others with your wish to die.

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 12, 2022, 01:21:20 pm
content: Quote from: tggzzz on October 12, 2022, 01:18:32 pmWe know that, but I was projecting the OP's vision on it

author: Gyro
author_rank: Super Contributor
timestamp: October 12, 2022, 01:27:31 pm
content: Quote from: pcprogrammer on October 12, 2022, 01:19:10 pmThis is exactly what had I assumed, but what happened in the documentary was nothing resembling that.

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 12, 2022, 01:33:46 pm
content: Quote from: Gyro on October 12, 2022, 01:27:31 pmFriends of ours are facing this for her mother and I understood that there is also the option to just drink some potion, and maybe that is less agreeable. I believe the mother choose for it, so will ask our friends how it was when it is over. The doctor told the mother to start practicing in swallowing a cup full in one go

author: Gyro
author_rank: Super Contributor
timestamp: October 12, 2022, 01:41:50 pm
content: That sounds like it! Maybe you can find the documentary somewhere on Youtube, I think it was the BBC.With every respect to the memory of your parents, the anasthetic followed by injection is the method used by vets in the UK. As you say, completely peaceful.

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 12, 2022, 01:55:41 pm
content: Found it on vimeo: video number is 229120539.Somewhere around 54 minutes in, a person drinks the stuff, and it is indeed less peaceful then what I experienced with my parents.