Thoughts on using air pressure to push fuel out of transport tank to machine.

[kthompson]

If memory is correct have bumped into a post in time past someone used air pressure to push the fuel from their transport tank to the tractor or what ever is being filled. I know the outlet would have to either have a drop tube or be on the bottom of the tank either on a side of the very bottom. Would then use a hose with nozzle to control the flow.

I have thought on it rather than buying an electric pump. Currently using a hand rotary pump. Considering on a diesel and gas tank. My tanks reside on trailer under my shelter with air line with in few feet of them. Both tanks are good metal tanks with standard pipe fittings.

 

[Industrial Toys]

Even a little air pressure can impose enormous stresses on a tank and it's welds. Stresses, it was never meant to see.

Probably many would warn you that compressed air and fluid is a bad combination almost always. I think I wrecked a water heater, by applying compressed air in an effort to drain it quicker once.

In any event. If you are going to do it, obviously use a regulator.

 

[kthompson]

Industrial Toys, been many years back but worked for a company who made heavy machines. Cranes to be exact. We used full air pressure for air tools to push fuel through the lines to bleed them. Never aware of any issue with a tank, filter or any part of the fuel line system. I think 80 psi can be an acceptable pressure for their water lines in some areas. It would seem water heaters would be designed for at least 100 psi but have no idea.

I don't think you would want the air pressure being released into the fluid for that would cause it to bubble and mix with the air. Thanks for your thoughts. I was thinking of something like 50 psi. But that is also one reason for my questions.

 

[grsthegreat]

Are there vents on those tanks? My tank has electric pump, but it must vent to outside air otherwise there would be a vacuum?

 

[crazyal]

I would be a little worried that if the fuel level got too low you would have air going down the fuel line. When that happens you'll have a volatile air fuel mixture. Chances are you'll never have a problem.

 

[Industrial Toys]

I'm not an expert, but was thinking more like 3 or 5 pounds, based on experience doing such things. Certainly, no more than is required to move the fuel.

Another good point. Is it possible to inject air into fuel? That wouldn't be any good at all.

I had a friend that ended up with a bone sticking out of his hand and was almost killed with a little 4" rotten turf tire that exploded on his bench and went into the ceiling. Compressed air can be extremely dangerous.

EDIT: Another Air pressure story. Went to see a customer years ago and he had his broken arm in a cast. Seems his Galvanized weed sprayer blew up. That might have saved me, because I had one that the pump was giving me issues and had in mind to put a schrader valve on the tank to avoid the pump altogether.

 

[kthompson]

grsthegreat, I would have to remove the vent while doing this and install a male air hose fitting to replace the vent when done.

crazyal, very good point. With reasonable amount of fuel in tank don't think that would be a concern but when pushing last of fuel in it just might be. Thank you for this thought. This one causes me concern.

industrial tools, very much appreciate you concerns with air pressure. How low of pressure would work not sure. Have another thought on the gas tank, could mount it on the mower trailer say two or so feet above the deck and let gravity just feed it to mower sitting on the ground. Have seen a few setups like that around.

As to injecting air into fuel, not sure how well you can, but believe you can certainly get air mixed into diesel or gas. Know you certain can have it happen with hyd oil but totally different pressure in a machine with air being sucked into it the system.


Thank each of you and this is why I posted my question. I believe it can be done and safely if pressure is kept reasonable for a fuel pump on a tank is pumping with pressure as it is also pushing the fuel. Seeing how strong of flow many have would believe the pressure is greater than 5 psi but doubt 20 pounds.

Each had good points and have decided to pass on this idea. I know a few years back read someone's post on doing this. My biggest concern would not be my using it but another family member. My oldest two grands this year have taken interest in tractor and mower and no way way think I could reasonable design a setup that would be simple enough for them to push the fuel and then become a vented tank when not fueling. Sincerely appreciate each ones thoughts and yes concerns.

As I finished typing above thought about injector lines that have failed and wonder with their pressure has there been any reported fire or explosion?

 

[Egon]

If the vessel is designed for your maximum air pressure and has a proper relief valve it may be possible but not advisable. Air fuel ratio can easily be within flammable parameters. It would not be allowed in industrial situations.

Best to forget the idea!

 

[beckmurph]

Compressed air is going to have moisture in it.

What psi is your vessel rated for.

Fluid in a drum vs compressed air in a drum is totally different.

 

[fried1765]

Even a little air pressure can impose enormous stresses on a tank and it's welds. Stresses, it was never meant to see.

Probably many would warn you that compressed air and fluid is a bad combination almost always. I think I wrecked a water heater, by applying compressed air in an effort to drain it quicker once.

In any event. If you are going to do it, obviously use a regulator.

I can't quite understand how you could over pressurize a water heater.
Unless the pressure relief valve was stuck closed?