Date: Fri Mar 13 16:00:29 2009 Back to Contents ------------------------------------------------------------------------

Author: Gary Karshner

Subject: Re: Ruben's tube and propane


One small comment on Propane. It is heaver than air, unlike natural gas and
can collect in closed containers. Your tube is relatively small and this
should not be a problem. It is not as dramatic a difference as using sulfur
hexafloride for sound demonstrations.

At 11:58 AM 3/13/2009 -0400, you wrote:
>Hi Cliff,
>Dale is correct in his description of how well propane works in the
>Reuben's tube.
>I actually don't know how many places I've used the Reuben's tube. In
>bars, libraries, schools, gyms, and outside (!) demo shows, all with many
>different air currents and winds. If you are really worried about the air
>movement, just make a sturdy plexi shield to stand one foot back and
>around the sides of the tube. I made one when I first built the tube 20
>years ago, but I never actually need it so I don't use it. You sometimes
>need to finely regulate the gas flow yourself to make the wave forms
>visible, and this will vary as you go from low frequency to higher
>frequency standing waves, but you quickly learn how to do that when you
>are using it.
>McMaster-Carr is a great place to purchase a 5 lb propane tank to use in
>shows and in classrooms. Since so many schools are taking natural gas out
>of the classroom for insurance and safety purposes, having your own tank
>guarantees you can perform the demo where and whenever you want and need to.
>BTW, my tube has size .04" holes, or 1.016mm, spaced every half inch for
>72". This seems to work pretty well.
>Happy gas tubing,
>Dale E. Stille wrote:
>>Zig and Dave Maiullo both run their tubes off propane using small 7 to 10
>>lb tanks with the standard pressure regulators. While you need different
>>orfices for things like stoves and water heaters for the different
>>gasses, I think you will find that the Rueben's tube is pretty forgiving
>>in this regard. So, you should be able to use it with either gas. I
>>would suggest getting the quick couplers for ease of attaching the tank
>>to the tube. ( They look and act the same as the couplers for high
>>pressure air hoses).
>> wrote:
>>>One of our faculty wants to use my Ruben's tube as part of a road show
>>>to a high school. The school does not have a natural gas source for him
>>>so he wants to rent a propane tank to fuel the tube. I am concerned
>>>about: how well this will work, as I seem to remember that propane
>>>requires different sized orifices for flame jets than natural gas,
>>>safety (a tank of gas under pressure near an open flame in front of a
>>>large audience) and finally, in our lecture hall use, I find I have to
>>>turn off our air handlers to reduce air currents in the room so the
>>>flames are stable.
>>>So I was wondering if any of you had experience using the Ruben's tube
>>>on the road in such circumstances and had any advice for me to pass along.

From Fri Mar 13 16:00:29 2009