Collins Overhung Tube (Prandtl Tube)
The Collins-Style Overhung Tube is used where the flow velocities are very high, or where it is impractical to have two holes in the pipe.
The Overhung tube is connected to the manometer the same way as the Straight Through Tube. Each side of the manometer is attached to a valve on the head of the tube.
The Overhung Tube is inserted into the pipe through a 3/8″ FPT hole or fitting. Therefore the Overhung tube cannot be inserted through the same hole as the Straight Through Tube, which uses a 1/4″ FPT hole or fitting.