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Pressurized fuel filling tanks?

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Jim Shumaker

Joined: 09 Jan 2006
Posts: 106

Posted: Sat Apr 01, 2006 3:29 pm Post subject: Pressurized fuel filling tanks?

DOES ANYBODY SEE A PROBLEM WITH PRESSURIZING A GAS TANK TO FORCE FUEL INTO AN AIRCRAFT????!!!

   

  I certainly have several problems with this method and none of them have good outcomes.  

   

  1)  Any leak in the container will force out fuel and/or volatile mixtures of gas air until the pressure is relieved.  That could be the whole 55 gallons or whatever.  

   

  2)  The leak will not manifest itself when you are actually at the tank and can take care of it.  

   

  3)   No mention of relieving the pressure was mentioned.  If there were such a relief the air gas mixture would probably be at an ignitable ratio and of a much larger volume than normal unpressurized venting.

   

  4)  How do you monitor the pressure in the tank.  Without a fail-safe system the potential for overpressure is great.  The risk of an overpressure include, leaks, rupture and explosion. 

   

  5) In the case of an overpressure without rupture there is a real possibility of spontaneous combustion.  Worst case is a shop air compressor connected to the tank to add a couple pounds of pressure.  The cell phone rings and a minutes distraction allows the nearly full tank to reach compressor tank pressure.  That is about 125 psi right?  10 to 1 compression in a cylinder would mean 147 pounds of pressure so we are close to a pressure where diesel engines operate without spark plugs.  Phone call means the flight is canceled.  Turn off the compressor and leave.  Now the tank is going to bake in the sun during the day and raise the pressure a little higher.  It won't take much to touch this off.  Did I mention this is a 55 gallon non certified barrel.  The lid didn't quite seal so a gasket was added to keep in that little 5 pound pressure.  But now the lid is not well grounded to the barrel and the little spark that jumps from the spout handle finds an easy path to jump INSI

 DE the

 barrel...and we have ignition!!!

   

  Has that actually happened?  well...maybe not the cell phone part....but it is fun to think about and the dangers are very real.  Pretty unrealistic anyways because a 55 gallon barrel would probably burst from that much pressure....and then ignite.

   

  And yes I AM an Electrician and Yes THIS STUFF ABOUT TANKS CERTIFIED FOR HAZARDOUS ATMOSPHERES, PRESSURIZED FUEL TANKS AND  PROPER GROUNDING IS IN THE CODES BECAUSE IT IS DANGEROUS.

   

  Jim Shumaker

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_________________
Jim Shumaker

dosmythe(at)cox.net
Guest

Posted: Sun Apr 02, 2006 7:23 am Post subject: Pressurized fuel filling tanks?

This always reminds me of a story I've mentioned before.  I used to work in 

Submarine Torpedo systems.  The torpedo tubes are 21" in dia. and close to 

2" thick with outer  muzzle doors that are held shut with 3000# of hydraulic 

on large pistons.  Every time there was work performed on the tubes, it was 

required to do an internal hydro to check for leaks.  Air pressure over 5 

PSI would cause the outer doors to creep open "against" the 3000# holding 

them shut.  Pressure is an awesome thing and would hate to see what 5 PSI 

would do to a drum.   I pressurized my glass fuel tanks and header with 

"MOUTH" pressure only and you could see the tanks bulge.

    I think the only type pump that would be somewhat safe is a small hand 

pump similar to blowing up basketballs.



Don Smythe

---

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msm_9949(at)yahoo.com
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Posted: Sun Apr 02, 2006 7:35 am Post subject: Pressurized fuel filling tanks?

I have sometimes used a Goat Throat hand pump to fill my tanks. It fits snuggly atop the fuel container and has a plunger that will pressurize the tank to 3-6 psi. This is enough pressure to force fuel up about 9' above its level in the container. When you're done, a relief valve on the side depressurizes quickly and safely. Sadly, it takes alot of pumping to maintain enough pressure to pump my tanks full, so  I've stopped using it even tho it's safe and clean. But my point is, I don't see why fuel can't safely be transferred from a tank temporarily pressurized at very low pressures, provided it is depressurized when not actively pumping.



James Shumaker <jimshumaker(at)sbcglobal.net> wrote:  



DOES ANYBODY SEE A PROBLEM WITH PRESSURIZING A GAS TANK TO FORCE FUEL INTO AN AIRCRAFT????!!!



I certainly have several problems with this method and none of them have good outcomes. 



1) Any leak in the container will force out fuel and/or volatile mixtures of gas air until the pressure is relieved. That could be the whole 55 gallons or whatever. 



2) The leak will not manifest itself when you are actually at the tank and can take care of it. 



3) No mention of relieving the pressure was mentioned. If there were such a relief the air gas mixture would probably be at an ignitable ratio and of a much larger volume than normal unpressurized venting.



4) How do you monitor the pressure in the tank. Without a fail-safe system the potential for overpressure is great. The risk of an overpressure include, leaks, rupture and explosion. 



5) In the case of an overpressure without rupture there is a real possibility of spontaneous combustion. Worst case is a shop air compressor connected to the tank to add a couple pounds of pressure. The cell phone rings and a minutes distraction allows the nearly full tank to reach compressor tank pressure. That is about 125 psi right? 10 to 1 compression in a cylinder would mean 147 pounds of pressure so we are close to a pressure where diesel engines operate without spark plugs. Phone call means the flight is canceled. Turn off the compressor and leave. Now the tank is going to bake in the sun during the day and raise the pressure a little higher. It won't take much to touch this off. Did I mention this is a 55 gallon non certified barrel. The lid didn't quite seal so a gasket was added to keep in that little 5 pound pressure. But now the lid is not well grounded to the barrel and the little spark that jumps from the spout handle finds an easy path to jump INSI

DE the

barrel...and we have ignition!!!



Has that actually happened? well...maybe not the cell phone part....but it is fun to think about and the dangers are very real. Pretty unrealistic anyways because a 55 gallon barrel would probably burst from that much pressure....and then ignite.



And yes I AM an Electrician and Yes THIS STUFF ABOUT TANKS CERTIFIED FOR HAZARDOUS ATMOSPHERES, PRESSURIZED FUEL TANKS AND PROPER GROUNDING IS IN THE CODES BECAUSE IT IS DANGEROUS.



Jim Shumaker



Marco Menezes

Model 2 582 N99KX

		

---------------------------------

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foxfloatflyer(at)hotmail.
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Posted: Sun Apr 02, 2006 7:53 am Post subject: Pressurized fuel filling tanks?

I owned a '59 straight tail 172 with an autogas STC. For several years I 

fueled from a 22 gallon drum that had a pickup tube to within a 1/2 inch of 

the bottom of the drum and a tire stem without core on the top. I used a 

small vibrator compressor with a regulator set at 5 psi and dispensed the 

fuel through a gas station style fuel hose and nozzle. The nozzle was 

grounded to the drum, which was grounded to my van, which I grounded to the 

plane and hanger. The system worked well and there was never evidence of air 

in the dispensed fuel.  I also have a pump rescued from an old gas station 

pump. It has a return path to relieve over pressure and to allow continuous 

flow for cooling. There is more evidence of mixing of the fuel with this 

commercial pump than with the air driven system.



Joel

Model 5 nearing completion

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