tank whistle

[John Dirks Jr]

What are the arrangements of different oil tank whistles? I'm talking about the whistles that let the fuel delivery person know the fill process is going correctly.

Are they usually visible? Consider a tank in a basement where the fill and vent tubes pass through the foundation wall to the exterior. Is there a type of whistle that could be installed near the top of a long vent tube, and therefore be visible for inspection?

[Bill Kibbel]

I can tell by the type of fitting for the vent pipe, where it attaches to the tank (I'll go try to find a pic).

I can't however, tell if it's working.

[Bill Kibbel]