How do tank vents work?

[Gary0747]

I cant find a diagram of how the tanks vent.  I see a tube inside of a tube but do not understand how they work?  I would think something would be designed to minimize plugging with ice? 

[1524J]

My vents are in the farthest point in the outboard fuel bay. The vent tube is located in the upper middle of the bay, extends up and out then down through the wing. Not sure why icing would be an issue as they exit under the middle of the wing. 

[carusoam]

24J handled the how they work normally aspect.

I have the other part of their existence....

Blocking a vent with ice would be a hazard.  More modern Mooneys have modified their tank vents and hid them in a backwards naca looking shape.  They are a bit larger diameter as well.  Older Mooneys shape the tank vent tubes to attempt to hide them from rain and icing events.

I have had a vent blocked by dirt daubers... The subtle hint was during pre-flight.  The tank seemed to be pressurized being out in the sun.

new Pre-flight rule.  Pressurized tanks are not normal for Mooneys.  Look further.  Check both tank vents.  Not checking the vents leads to oil canning of the sheet metal.  Nobody likes to see that with their new to them plane.  Who new we had dirt daubers in NJ?

does ice have a tendency to not form on the bottom of the wing?

do other airframes heat their tank vents?

Best regards,

-a-

 

[Gary0747]

What do you use to make sure the vents are not plugged?  Wire up both inner and outer tubes?

[carusoam]

I believe Piloto had put some recommendations around here somewhere.  

Searching on blocked tank vents and wire will probably uncover it.  

Connecting a tube and blowing through it works as a check.  Cap off first.  The risk is sticking something further up inside the tube or getting dirt in the tank.

 

Just PP ideas, I am not a mechanic.

 

Best regards,

-a-

[bradp]

The function of your vents are checked indirectly during your fuel cap leak check at annual.  M20-239 or thereabout.  Should be part of a good preflight.   Just don't suck up any 100LL   :-)

B