2.2 Transmitting Through a Tank Wall

It is possible to transmit through most tank walls because the ultrasonic waves travel through tank walls with no issues depending on the measurement requirements and mounting techniques. Soft tank materials, such as automotive HDPE (High Density Polyethylene) and Stainless Steel, have been tested with good results. The process has two key features to maximize success:

1. Good mechanical connection between the transducer and the tank wall. This is achieved using Cyanoacrylate adhesive as it cures quickly with low compressibility and high adhesion to most materials.
2. Transducer backside acoustic dampening (and wire strain relief). This is achieved using “Hot glue” as it has high adhesion to acrylic and moderate flexibility allowing for both acoustic dampening and good wire strain relief. Commonly available silicon RTV can be used instead but requires a longer (24 hr) cure time.
3. The tank wall is homogeneous (has no air gaps and/or is not porous in nature). Air gaps cause reflections and can attenuate the ultrasonic waves, thus prohibiting them from passing through the wall.