Hank Roberts 2 mode liquid fuel stoves@ possible?

[al b]

I noticed that HJ said that the Hank Roberts 2 stoves could burn liquid butane (in cold weather) due to a wick into the special canister:

Is there a reason this method cannot be used with liquid fuels such as kerosene/white gas? It would avoid having to pressurize the fuel can: just put a wick inside the fuel tube.
Surely, the (primed) generator tube can create gas pressure for burner from the expansion of liquid to vapour?

NB not a MYOG stove modifying question.

[Drowned Lemming]

Is this not what the Optimus Svea, 8R and 99 (and probably others) use?
There is some amount of self-pressurisation as the stove heats up, but no manual pumping is required – the only pump is an optinal extra.

[al b]

I was thinking that the Remote tank could be kept (for safety/convenience),

[Stuart R]

The Optimus 8R does have a wick inside the tank, but the stove won't work uless the tank is pressurised, either by heat from priming or from the (optional) pump.

>>Surely, the (primed) generator tube can create gas pressure for burner from the expansion of liquid to vapour.

No, the pressure has to come from the tank in order to force the gas out thru the jet

[al b]

I thought perhaps the wick could bring the liquid fuel to the generator tube where it could be vapourised by burner heat, then the expansion would supply the pressure to burner (presuming stove is primed with separate alcohol).

The Hanks stove was butane only, so the wick must have transported the butane when below 0,5C, then heat vaporized to gas, and burnt as normal: no pumps or propane for pressure.

[al b]

I wondered if HJ knew of the internal structure of the Hank Roberts and whether the idea could be extended to modern liquid fuel (kero/white gas) stoves.

[Hikin’ Jim]

Alan,

Stuart is correct that while stoves like the Optimus 8R/Primus 71/Svea 123/Optimus 99 had wicks, they relied on thermal feedback to pressurize the tank and with out that pressure, the stove would not work.

Now, is the HR sufficiently different in its design to allow operation on butane when there is no pressure in the canister? Probably not. The HR will work with 100% butane even in pretty cold weather, but, still, the HR operates on pressure created by thermal feedback. An HR canister says on the side that the canister needs to be warmed if the temperature is near freezing.

In other words, you need a little initial pressure to get things going. Once things are going, the thermal feedback can drive the system.

Absent that initial pressure, I don't believe the stove will work, and I'd say that this wouldn't be a good approach for white gas and certainly not kero.

HJ
Adventures In Stoving

[Nick Gatel]

I have lots of experience with Svea 123s (wick in tank) and with Hank Roberts style cartridges (Mark III and an Optimus 731).

The wick in a Svea goes up into the tube, but cannot deliver enough fuel unless the tank is pressurized. Actually in perfect weather you can cup the tank in your hands and it will warm the tank enough so fuel will dribble out of the jet and fill up the priming dish. But the stove will not operate until you burn the fuel in the dish and heat/pressurize the tank.

The Roberts style stoves are difficult to light and get going. They sputter around for a minute or two until everything warms up. The Marks used the canister laying on its side, and the 731 canister was vertical. Although these are liquid feeds, they still rely on the pressure in the can to deliver the liquid. And they did not work well at cold temperatures.

[al b]

Thanks for the info.

So for kerosene you either pressurise or use a zelph style passive burner (like a mini greenhouse heater). One of such zelph burners to suit a trangia might be nice, to save on fuel volume compared to meths.

[Author]

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