On 05/14/2013 08:10 PM, Danny D. wrote:
On Tue, 14 May 2013 19:33:30 -0700, jim beam wrote:

not to mention the increased spillage trying to get them to work...

Seems to me they mandated the gas stays *in* rather well; but
not that the gas comes *out* gracefully.

The cost of the complexity is (it seems):
a) The increased spillage of gasoline
b) The increased vapors from gas left in the can (see note 1)
c) The increased cost & complexity of the spout
d) The increased time it takes to pour the gas out

Note 1:
I can't get all the gas out of the can with the spout on.
I presume all that gas will vaporize and fill the can with
gasoline vapors, which, will stay inside due to the lack of
venting and permeability - but - they will immediately escape
the moment the spout is removed for the refilling tasks.

Given that we spill more, and we vent more when we open the
gasoline can to refill - yet - we certainly vent *less* during
storage and during the pouring tasks ... I wonder where the
balance of the equation lies?

Does anyone know of any data on what we're actually saving
in vented gasoline vapors?


for anything more than a few hours storage, there's no question that
fully sealed will lose less. this is because the sealed can vapors will
reach equilibrium and after initial vaporization inside the can, it will
then stop once its magic vapor pressure is reached. with a vented can,
that never happens, and it continues to leak out forever until all gone.

so, re storage, these cans are a win. but on pouring, which is the
whole point of the can in the first place - most people use cans to
transport gas, not store it - these "no leak" cans are a joke. maybe if
you're filling a lawn mower they work, but for a car with the fuel cap
only accessible from a vertical plane, it's pretty much impossible to
pour more than about 30% of contents without spillage. and that's
assuming you've /not/ given up on the spout and are not using a
newspaper or other improvised funnel.

bottom line, these things need to be re-thought. preferably by someone
with a car.


--
fact check required