[boglins]

boglins on March 10, 2017 at 8:22 am · in reply to: food on a route #4236

How much difference does bigger orifices make? It would be hard to make generalizations. It is too dependent on the fuel blend, the ambient air temperatures, the ambient atmospheric pressure, the specific stove model, and how long you’ve currently been using the stove and thus lowering the temp of the canister. It may mean that below -5F on the chart above, both stoves stop working entirely. And that does not say anything about what happens 4 minutes into using the stove at -5F. At that point, the canister itself may have cooled through evaporation to -20F or -30F, rendering it mostly useless.

[boglins]

boglins on March 10, 2017 at 7:48 am · in reply to: food on a route #4234

There is indeed a lot of marketing in regards to the benefits of regulators and their effect on cold weather performance. The truth, though, is that regulators cannot raise the pressure of their fuel. However, there is one other thing going on that may help explain the difference in some stoves’ performances: non-regulated stoves should be designed for all conditions, including when it is hot outside. Non-regulated stoves have to be safe to use when it is 100 degrees out. In order to keep those stoves safe to use, some non-regulated stoves are intentionally handicapped by making their gas orifices smaller. That way they don’t let out too much gas when ambient temperatures are up. Those stoves will have poor performance in the cold, but they will be safe when it is hot. Regulated stoves can have bigger gas orifices, as the regulator simply closes off flow in warm ambient temps and higher gas pressures, but the regulator can fully open in lower temps and the resulting lower gas pressures. So some non-regulated stoves have smaller jets than some regulated stoves. In that way, some regulated stoves may perform better than some non-regulated stoves in the cold.

However, a definition of “cold” is necessary. The canister will be cold from ambient temps, and it will get colder with use due to the physics of evaporation as the gas inside expands. If the temperature of the canister drops below the temperature that the fuel inside evaporates, no canister stove will work with or without a regulator. The fuel will simply sit in the canister as a liquid. Butane boils at 31 degrees F, isobutane boils at 11F, and propane boils at -44F. The temp where your canister will put out gas will be based on the amount of each of those fuels in your canister.

Some stoves get around the problem of evaporation by having inverted canisters or canisters on hoses that allow you to flip the canister. This allows liquid to enter the line, presumably pressurized by propane in the mix. This is fed to a loop of fuel line within the flame of the stove. This acts as a heat exchanger of sorts, vaporizing liquid fuel in the fuel line and powering the stove

[boglins]

boglins on March 9, 2017 at 5:14 am · in reply to: food on a route #4221

No, this is a common misunderstanding. Fuel regulators have little or no effect at low temperatures at helping mitigate the effects of cold on stove performance. Regulators are very capable of lowering pressure, but they cannot raise the pressure of the source fuel. The only way to raise the pressure of the source fuel is to increase its temperature through some sort of heat exchanger: the method Steve suggested, placing the canister in a pan of water and using the water to help keep the canister above freezing, and choosing canisters with higher percentages of propane and isobutane rather than butane, as they vaporize at lower temps.