Forum Index » GEAR » Pre-heat tube on cannister-top burner: reasons why?


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Stuart R
(Scunnered) - F

Locale: Scotland
Re: Re: Re: Pre-heat tube on cannister-top burner: reasons why? on 09/13/2011 02:10:52 MDT Print View

If the gas is near it's boiling point, there will be little pressure in the canister (by definition), so the "needle" valve (I've yet to see a canister stove with a true needle valve) will be fully open to maximize the gas flow. The only pressure drop will be across the jet. All the same, I was impressed by the technical terms you tried not to use but did.

+1 on the post beer and pizza night design

Hikin' Jim
(hikin_jim) - MLife

Locale: Los Angeles, CA, USA
Re: Pre-heat tube on cannister-top burner: reasons why? on 09/13/2011 10:33:54 MDT Print View

If the tube is before the needle valve...
It appears from the photo that the pre-heat tube is after the valve -- which I think would make more sense in any event (why have gas in the pre-heat tube when the valve is closed?).

I still think there's going to be heat conducted back to the tank although goodness knows exactly why they'd pick this design. Beer and pizza night? Tequila shot night more like. Or maybe they were testing alcohol stoves and had some 190 proof ...

I suppose a simple way to test my heat feedback theory is to run the stove for a while and then feel the top of the canister. If the top of the canister is at all warm or even simply room temperature, then there's heat feedback going on. Normally, a canister should be pretty cold after a stove has been in operation for any length of time.

HJ

Rick Dreher
(halfturbo) - MLife

Locale: Northernish California
Re: Pre-heat tube on cannister-top burner: reasons why? on 09/13/2011 10:43:46 MDT Print View

"I suppose a simple way to test my heat feedback theory is to run the stove for a while and then feel the top of the canister. If the top of the canister is at all warm or even simply room temperature, then there's heat feedback going on. Normally, a canister should be pretty cold after a stove has been in operation for any length of time."

True, that. Absent a windscreen I often find canister temps drop during use, I suppose from evaporative cooling.

I'm still lobbying for further disassembly. Inquiring minds want to know!

Cheers,

Rick

Eric Blumensaadt
(Danepacker) - MLife

Locale: Mojave Desert
Hmmmm... on 09/13/2011 11:04:31 MDT Print View

My recommendation to actually use the pre-heat tube to best advantage is to get a Brunton "remote canister kit" that converts a canister-top stove to a remote stove. REI sells them.

With this kit you also should then get a new angled MSR plastic tripod stand (from their new multi-fuel stove) to invert the canister. Then your stove's heat tube will function in colder weather.

That said, I still rely on my MSR Dragongly liquid fuel stove for cold weather B/C it's utterly reliable. Haven't used my ancient (1971) SVEA 123 for over a decade.

Alan Bradley
(ahbradley)
No disassembly, sorry on 09/13/2011 13:14:55 MDT Print View

Sorry, no further disassembly: might be destructive.

Hikin' Jim
(hikin_jim) - MLife

Locale: Los Angeles, CA, USA
Re: No disassembly, sorry on 09/13/2011 17:42:57 MDT Print View

lol. Yeah, cutting a stove in half just *might* be destructive.

Any interesting in running the stove for a few minutes to see if the uppermost portion of the canister stays room temperature or above?

HJ

Larry De La Briandais
(Hitech) - F

Locale: SF Bay Area
Other fuels? on 09/14/2011 21:24:49 MDT Print View

Maybe there is an option to use other fuels that need the preheat tube, such as white gas?

Hikin' Jim
(hikin_jim) - MLife

Locale: Los Angeles, CA, USA
Re: Other fuels? on 09/14/2011 22:55:58 MDT Print View

Well, considering that it has threads to screw into a canister (just like a Pocket Rocket does), probably not.

HJ

Paul McLaughlin
(paul) - MLife
Re: Re: Pre-heat tube on cannister-top burner: reasons why? on 09/15/2011 21:03:04 MDT Print View

I for one would love to see this thing taken apart to determine if that is indeed a pre-heat tube, or simply a heat conductor. Functionally there would be very little difference on an upright canister.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Pic of preheat tube on 09/16/2011 01:52:37 MDT Print View

Blimey. I think that has to be a classic example of a totally confused design team. Taking the stove as shown, there is absolutely no reason for the preheat tube to exist.

One explanation is that the stove was an very early Chinese produuction, where the Chinese had no idea what they were doing!

Nicely made, but wierd ...

Cheers

Edited by rcaffin on 09/16/2011 01:55:11 MDT.

Alan Bradley
(ahbradley)
Thanks on 09/16/2011 06:59:11 MDT Print View

Thanks, so I suppose the only possible reason is to avoid flaring if knocked over: knocking it over still dangerous though. :)

Edited by ahbradley on 09/16/2011 06:59:58 MDT.

Alan Bradley
(ahbradley)
Stove made in England on 09/21/2011 09:54:21 MDT Print View

According to the label, was made in England.