The human ear cannot register the leaking of gas from faulty ring lines and pipe systems. However, ultrasound equipment from FORCE Technology and subsequent repair work has helped Maersk Container Industry AS to cut its gas consumption by one third on each container, of which the company welds 8,500 each year.
Maersk Container Industry saved a lot of money using
ultrasound equipment from FORCE Technology
Maersk Container Industry, one of the most high-tech companies in Denmark in the welding industry, suspected that its comprehensive systems for protective gases were leaking. Several pipes appeared to be crumbling and a sample test using leakage detecting spray confirmed the company’s suspicion.
Small leakages – big losses
Even small leakages can produce big financial losses and increase the risk of injury and environmental issues. A leakage at a poorly maintained plant frequently represents 20-40% of the consumed air volume. For example, compressed air equalling an electricity consumption of 3.1 kW leaks from diameter 3.0 mm at an excess pressure of six bar. Thus, even a small leakage may result in a major loss.
This sparked a reaction from Maersk Container Industry, who operates many kilometres of ring lines and pipe systems. However, the location of the systems (below the ceilings and eight metres above the floor level) made it difficult to further examine the leakages. An examination would be both timeconsuming and costly.
Acoustical ultrasound equipment used to record leakages
Instead Maersk Container Industry decided to make use of simple, acoustical ultrasound equipment from FORCE Technology, which represents a simple and elegant solution. The equipment generates noise that is recorded by the human ear when gases escape from leakages of a certain size. The equipment makes use of a directional, highfrequency microphone and a filtering system that excludes low frequencies and thus prevents ordinary noise from affecting the equipment. Leakages are located by listening with the use of loudspeakers or headphones. The equipment does not have to be in the proximity of leakage but is able to detect any leakage at a distance of several metres under optimum conditions.
All leakages were detected in a single day
FORCE Technology needed one day only to examine most of the ring line system. The microphone of the ultrasound equipment was mounted on a lever, rendering scaffolds, lifts and ladders redundant.
The leakages recorded in pipes and galvanised joints were marked by yellow stickers. The biggest surprise, however, was the leakages in the regulator couplings, and broken glass that presented a previously ignored problem.
Although Maersk Container Industry suspected numerous leakages, it was surprised by their magnitude. Even when the welding processes were suspended, the company experienced a significant idle consumption of gases.
As a matter of fact, an analysis made shortly after the correction showed that Maersk Container Industry had cut its gas consumption by more than one third for each container, which runs into large volumes with 812 metres being welded on 8,500 containers every year. Therefore, Mærsk Container Industry decided to cut back on the long pipe connections by expanding its system with permanent copper pipes and welded joints. Moreover, the company is considering a similar leakage analysis of its compressed air system.
The ultrasound technology is an obvious choice for leakage detection in pressurised plants such as compressed air plants, oxygen and gas systems. Experience tells us that leakages frequently occur in conjunction with hand tools, cylinders, pipe connections and the like while pipe systems are reasonably leakagefree.