Inside the tank is an enclosed measuring device with holes that allow the fluid couplant
to enter the chamber between the transducer and a reflecting surface.
His approach is based on the theory that the "optimum couplant
concentration defines optimum dispersion and the most efficient packing of particles.
It is then assumed that the performance of the UT and couplant
This technique required a liquid couplant
, which was not a problem in a sawing situation where water coolant was present.
In addition, the type of couplant
was reported to influence the result of the ultrasonic property measurements .
Because the pipeline typically transported gas, the inspections were conducted in either a water or diesel batch so that the inspection tool had the necessary liquid couplant
required by use of ultrasonic sensors.
Each time the transducers were moved, the acoustic couplant
material was cleaned from the transducers' faces and a new coating of couplant
The application of the traditional piezoelectric transducers for inline inspection requires a liquid couplant
for ultrasonic energy and signal transfer into the pipe wall.
Sensors are coupled to the structure by means of a fluid couplant
Since the material being inspected acts as its own transducer, the need for a liquid couplant
Traditional ultrasonic technologies (UT) based on piezoelectric transducers are only applicable when an adequate liquid couplant
is available between the transducer itself and the pipe wall.
At these frequencies a liquid couplant
between the transducers and the surface is not necessary.
However, ultrasonic inspection currently squires putting a liquid couplant
in a gas pipeline.
The tool has a target inspection specification similar to the UltraScan CD tool, but does not need to be run with liquid couplant
, making it ideally suited to operation in gas pipelines.
The tool had be locate all defects accurately and be able to work in a gas pipeline without the need for introduced liquid couplant