What you gain from choosing the right X-ray system

Two views of the same inspection

A pipeline is assembled one pipe section at a time. Each circumferential weld becomes part of a pressure-carrying system. Qualified welding procedures reduce the risk of defects, but cracks, porosity, inclusions, incomplete penetration, and lack of fusion may still be hidden inside a weld. Radiography gives inspectors an image they can assess against the applicable procedure and acceptance criteria while a repair is still possible before commissioning. Jan warns, “Defects that compromise the integrity of a weld may result in a disaster after commissioning of the pipeline.” Allen adds, “Failure of an inspector to perform at the highest levels of integrity during the inspection process will cost lives, material, and money.”

A costly choice in the field

Allen gives a field example, “A typical failure in the field that can lead to delays is choosing the wrong inspection method or equipment. For example, choosing to use an EVO 300DS on a 36-inch diameter pipe with a liberal acceptance criteria versus choosing an EVO 300D/1200 could save hours of shot times.”

What the equipment can do

Jan explains the output choice, “If there is no access to the end of the pipeline, double-wall techniques have to be used. For this application, the EVO 300D/1200 delivers a third more power than a 300 kV, 900 W constant-potential system, and is designed for long-duration exposure.”

EVO 300D/1200 - 1200 W · 3,0 mm spot · 40° x 60°

In the directional EVO range, the 300D/1200 combines 300 kV with up to 1.200 W and a 3,0 mm focal spot. It is the high-output option for demanding exposures through more material. Allen sees that advantage most clearly as pipe diameters and wall thicknesses increase. Allen describes the scale of the work, “Pipeline diameters are ever increasing in size and thickness to accommodate higher volumes of product to get to the production plant. Pipeline diameters are increasing to a maximum of 42–46 inches, which puts today’s portable X-ray systems at their limit for double-wall exposures and RTR systems. This is why 1200 W is so valuable in today’s pipeline environment for shorter shot times and faster inspections.”

Where image detail changes the choice

The 300D/1200 and 300DS answer different inspection needs. The four-model comparison later in the article shows how each is available with air or water cooling. The smaller focal spot can reduce geometric unsharpness, depending on the inspection geometry. Whether that advantage matters is set by the required image quality. Where penetration and exposure time govern, the higher-output system may be the better choice.

What higher output changes

Higher output can shorten an exposure when the amount of radiation reaching the detector is the limiting factor. The gain depends on technique, geometry and setup. The worked examples below use a 25% reduction in exposure time as an illustration, not a fixed result for every weld.

In this RTR example, 11.25 minutes less scan time per weld changes an illustrated 120-weld job from 20 working days to 18. Design as a compact comparison graphic tied to the assumptions above.

An eight-hour shift allows six complete weld scans at 75 minutes each, or seven at 63,75 minutes each. For 120 welds, that is 20 working days versus 18 when rounded up to whole working days.

Cycle time per weld: 45 + 30 = 75 min with a 900 W system

33,75 + 30 = 63,75 min with the EVO 300D/1200.

A second example with film

A film-based job might run 40–60 exposures a day, including repositioning, with four to five exposures per weld. At five minutes per film with a 900 W system, exposure takes 200–300 minutes of an eight-hour day, roughly half. With the EVO 300D/1200, each film takes 3,75 minutes.

The RTR calculation includes the time needed to move the gantry. The film example makes the same point: faster exposure shortens only the exposure part of a job. Both examples are illustrative. These examples separate time spent exposing from time spent positioning and moving. The next constraint is whether the system will complete each exposure reliably in the field.

T(job) = T(exposure) + T(positioning) + T(other)

If exposure accounts for ten days of a 20-day job, the other work takes ten days. Cutting exposure time by a quarter gives 0,75 × 10 + 10 = 17,5 days.
Illustrated result: 20 days → 17,5 days

Reliability has to extend beyond the tube.

Jan elaborates, “Everything from the metal-ceramic X-ray tube and constant-potential high-voltage generator to the shock-absorbing housing and AC mains management inside the control unit has to withstand the environment in which it works.” The EVO tube heads are rated IP65, and CONTROL EVO is IP66. The control unit uses power factor correction for unstable mains supplies and generators.

This matters when dust, moisture, or uncertain power could stop a crew from completing the required exposure. Allen remarks, “Time is money, and delays cost money to both the pipeline company and the inspection company.” Equipment choice affects the crew, the schedule, and the customer. Cooling and reliability help the crew complete that required work without avoidable delay.