What is GUL Testing?

GUL Screening uses guided wave technology as a solution to the rapid detection of corrosion, erosion and other damages in steel pipes and rail. This is an advanced non-destructive testing (NDT) method used for pipe and rail inspection.

How do Guided waves work?

Guided wave testing (GWT) is a non-destructive evaluation method. The method employs acoustic waves that propagate along an elongated structure while guided by its boundaries. This allows the waves to travel a long distance with little loss in energy.

What are guided waves give examples?

Lamb waves are guided waves traveling along thin plates, whereas Rayleigh waves are guided waves constrained to the surface. Guided waves can also exist in solid and hollow cylinders, as well as in shell structures.

What are guided wave devices?

Optical guided-wave devices built with photolithographic fabrication techniques and electro-optic substrates are compact, low drive power devices that provide these functions. Research is particularly advanced on integrated-optic devices based on waveguides formed by titanium diffused into lithium niobate.

How guided waves can be formed?

When an electrical voltage is applied to PZT mounted on a plate-like target structure, guided waves are generated and propagate along the target structure. Then, the corresponding responses can be measured by the same PZT in a pulse–echo mode or by the other PZT in a pitch–catch mode.

What is Toft inspection?

Time of flight diffraction is an advanced non-destructive testing method used for weld inspection. Time of flight diffraction (TOFD) is one of the most reliable non-destructive testing methods in testing welds for both pre-service and in-service inspection.

How is guided wave ultrasonics used for NDT of risers?

Guided wave ultrasonics is now an accepted tool for the NDT of risers. Currently it is used to screen risers for corrosion. It can locate the areas that require further evaluation with techniques such as ultrasonic corrosion mapping. Future developments may include techniques that allow GWU to map corrosion.

Why can’t the guided waves reach the bottom of the riser?

The range of the guided waves is severely limited by coatings around the pipe. If they are ‘sticky’, they will adsorb the ultrasound. It is then not possible to reach the bottom of the riser. In some cases the sticky nature of the riser coating in the splash zone is enough to absorb all of the ultrasound.

What is the effective range of guided wave inspection?

Under good conditions, GWT inspects over 330 ft in uncoated, straight, gas-filled pipe. Most pipes will have an effective range of between 16 ft – 165 ft. The effective range for guided wave inspection can be inhibited by: Coatings: bitumen wrap and similar heavy coatings cause high attenuation

Can guided wave ultrasonics detect corrosion in pipes?

Paper no. 29407. Guided wave ultrasonics is now an established technology for detecting corrosion in pipes. The technique is principally applied to pipe that is insulated, buried or otherwise inaccessible to conventional NDT. TWI has experience in applying the technique to offshore risers, where there are specific problems.