Well, for those of you who don't know, I work as a full-time small engine mechanic. Last year, I grew tired of smelling gasoline fumes every time I had to drain the gas tank on a mower or generator which needed carburetor work. Ethanol is wreaking havoc on lawn equipment fuel systems, and it is not uncommon for me to have to do two or three carburetor jobs a day during the busy season.
SO, it was time to get creative and find a way to suck a tank dry without draining gasoline into an open pan, or spilling it onto the floor. We had an old 30-gallon air compressor tank sitting around the shop, and I found a basic, Harbor Freight Tools air-operated vacuum pump sitting on the shelf in the tool room. With a little welding and a couple trips to the plumbing supply store two buildings down, here's what I came up with:
It works great! Since the whole system is pneumatic, there is no chance of an electric vacuum pump starting a fire or causing an explosion. I can suck the average 3-quart fuel tank dry in about 60 seconds. Problem solved!
The suction hose is nothing more than reinforced 3/16" ID air hose. I installed a female coupler onto the end of the suction hose so that you can unclip it from the top of the tank and attach it to the drain valve VVVVV on the bottom. You can then install a pressurized air line where the suction hose used to go, which will pressurize the tank and force the gas out through the bottom.
There's the drain valve system, installed on the bottom of the compressor tank, where the moisture drain valve used to go.
Here's a close-up of the reinforcement to the vacuum line I built. I just welded a washer to a piece of steel bar to prevent the long neck from accidentally breaking off. Just in case somebody gets in a hurry with the ball valve. People at our shop can be rough on tools.
This whole machine needs a little refinement, such as the installation of a vac/pressure gauge and a larger diamter drain valve system, but it works well enough as-is for its intended use. I'm sure the whole thing will be painted properly before all's said and done. Look out rotten gas! Braaaptor's coming for you and he's got a big sucker....
SO, it was time to get creative and find a way to suck a tank dry without draining gasoline into an open pan, or spilling it onto the floor. We had an old 30-gallon air compressor tank sitting around the shop, and I found a basic, Harbor Freight Tools air-operated vacuum pump sitting on the shelf in the tool room. With a little welding and a couple trips to the plumbing supply store two buildings down, here's what I came up with:
It works great! Since the whole system is pneumatic, there is no chance of an electric vacuum pump starting a fire or causing an explosion. I can suck the average 3-quart fuel tank dry in about 60 seconds. Problem solved!
The suction hose is nothing more than reinforced 3/16" ID air hose. I installed a female coupler onto the end of the suction hose so that you can unclip it from the top of the tank and attach it to the drain valve VVVVV on the bottom. You can then install a pressurized air line where the suction hose used to go, which will pressurize the tank and force the gas out through the bottom.
There's the drain valve system, installed on the bottom of the compressor tank, where the moisture drain valve used to go.
Here's a close-up of the reinforcement to the vacuum line I built. I just welded a washer to a piece of steel bar to prevent the long neck from accidentally breaking off. Just in case somebody gets in a hurry with the ball valve. People at our shop can be rough on tools.
This whole machine needs a little refinement, such as the installation of a vac/pressure gauge and a larger diamter drain valve system, but it works well enough as-is for its intended use. I'm sure the whole thing will be painted properly before all's said and done. Look out rotten gas! Braaaptor's coming for you and he's got a big sucker....
