idea to stop gas leaks <$30

[Lance2]

To find a gas leak the first idea is to use a flow sensor, but the flow rate of a leak is so low it can't be measured reliably.

I have an idea for a system to detect a leak and turn off the gas supply, and I'm pretty sure the parts would cost less than $30 (from ebay). It requires:
- solenoid vale ($10)
- pressure switch ($5)
- controller e.g. arduino ($15)


The valve and pressure switch are connected to your gas lines this way:

[A]
cylinder ----- regulator ----- valve ---+--- keg --- taps

|
pressure switch

So in summary the valve is able to cut off the flow from the regulator, and the pressure switch is responding to the pressure after the valve. Let's say the pressure from the regulator is 10psi and the pressure switch turns on at 5psi.

It works like this:
* Initially the pressure at A and B are equal (10psi), the valve is closed, and the switch is on (because it has 10psi on it)
* Eventually the pressure at B drops either because the tap is opened or there is a leak
* In response, the controller turns on the valve for 1s to let the gas flow, then closes it again.
* If the cause of the pressure drop was a leak, then after closing the valve the pressure at B will not drop again for a long time. The controller will keep the valve closed, and maybe also beep or flash an LED until a reset button is pushed
* If the cause of the pressure drop was a tap opening, then after closing the valve the pressure at B should drop again quickly. The controller continues opening the valve for 1s intervals as long as the pressure drops quickly after it is closed.


Can anyone see any problems or improvements?

 

[NickB]

What's wrong with submersing your gas lines and connectors in water and watching for bubbles? Not to put your idea down but it looks overly complicated for what you're trying to achieve.....

Cheers

 

[Burt de Ernie]

or Soapy water on the joints??

 

[GalBrew]

Or spray starsan on lines/joins....

 

[MartinOC]

I'm guessing Lance is an engineer........? No offence, mate....

 

[Lance2]

What's wrong with submersing your gas lines and connectors in water and watching for bubbles? Not to put your idea down but it looks overly complicated for what you're trying to achieve.....

Cheers

Every time you make/break a connection (swap a keg etc) you can create a new leak so you need to constantly monitor for it.

 

[GalBrew]

Every time you make/break a connection (swap a keg etc) you can create a new leak so you need to constantly monitor for it.

You are quite correct. Everytime a make a new connection or replace the lid on a keg, I spray with starsan and look for the bubbles.

 

[Nibbo]

I'm thinking your first line "To find a gas leak the first idea is to use a flow sensor" is a little off. My thinking would be the flow sensor would tell you there is a leak or Co2 movement, not find the leak.
If you could design something that could save a full bottle of Co2 for less than $30, that would be handy. Maybe not for people who can access Co2 rather easy but for people who have to plan their week/month on when they can re-fill their empty Co2 bottle it may be worth while. Especially since it would be cheaper than a refill.
Also, you would need to consider how you carb your beer. If you carb at serving pressure like me, you would need something to override it to allow the gas to slowly move into the keg which may look like a leak to the controller.
Just a few thoughts...

 

[TheWiggman]

One major query - apart from turn on and off when demand drops, what does it do? If the keg was carbing it would behave like a leak (ie pressure drop at B, recharge, pressure drop again etc)
Are you considering incorporating logic to take time into account and determine conditions for scenerios? Try to get gauge on the purpose of this.

 

[DJ_L3ThAL]

I found a CO2 surface mount sensor which would be a better leak detector and could power a relay to close an actuated valve on the reg outlet if it picks up a certain concentration in the bottom of your keezer or kegerator.

I was planning on wiring up a buzzer to go off as an alarm but a shut off valve would be full time protection.

Was planning on doing it then posting a tutorial here or even selling pre-made boards. But the idea came to me over a year ago when I built my kegerator and lost a bottle because I didnt check under water... still haven't moved on the idea so attached is spec sheet. Get em from jaycar.

 

[jaypes]

I have a $0 solution

Turn off the cylinder when not in use (keeping kegs charged to avoid de-carbonation)

 

[DJ_L3ThAL]

Does cover those who carbonate at serving pressurr...

 

[jaypes]

You could rig up a sensor under the tap controlling a solenoid so during a session the keg remains at serving pressure. When not in use the solenoid is closed.

Like the motion activated bathroom water taps you see at shopping centers/airports etc

 

[n87]

Bottle!


.... ok... maybe im just trying to get back at the responses whenever someone has a bottling question...

 

[DJ_L3ThAL]

Yes but you normally dont pour beer through the taps, or in my case I dont even tap the keg whilst carbonating. Which is the longest amount of time a CO2 bottle needs to be open without restriction

 

[Lance2]

Also, you would need to consider how you carb your beer. If you carb at serving pressure like me, you would need something to override it to allow the gas to slowly move into the keg which may look like a leak to the controller.

Good point, didn't think of that. Maybe holding the reset button for a full second causes the controller to ignore leaks for a couple of days. Or you could just press the reset button every day while carbonating, or the supply to the carbonating kegs could bypass this.

One major query - apart from turn on and off when demand drops, what does it do? If the keg was carbing it would behave like a leak (ie pressure drop at B, recharge, pressure drop again etc)
Are you considering incorporating logic to take time into account and determine conditions for scenerios? Try to get gauge on the purpose of this.

Yes it's like a flow meter that works by cutting off the gas momentarily then timing how long it takes for the pressure to drop. You have to define some rate that corresponds to dispensing and everything less than that is considered a leak.

I found a CO2 surface mount sensor which would be a better leak detector and could power a relay to close an actuated valve on the reg outlet if it picks up a certain concentration in the bottom of your keezer or kegerator.

That's pretty clever you should have tried it

 

[DJ_L3ThAL]

One day mate. One day haha

 

[HBHB]

Another possible solution:

Use a HD thicker walled and generally better quality Gas line that will never blow out. ie 6mmx10mm Valpar Line or similar level of quality for a few cents per meter difference.

"Just saying"

Martin

 

[DJ_L3ThAL]

Is Bevex one of these higher quality lines?

 

[TheWiggman]

I had a leak once that was at the regulator itself (on one of the gauges). Unfortuately short of the ol' detergent bottle trick, I don't think any of the above will address that.
I have the slowest of leaks somewhere at the moment and it's driving me nuts. It's somewhere on the line side. Somewhere.