Although viscometers were already present in each of the two fuel boosters, operators were concerned about the reliability of the instruments because of inconsistent readings and ongoing maintenance requirements.

BornholmsTraffiken called upon measurement and control specialist Mobrey Measurement to advise on how best to address these issues.

"We needed accurate, reliable instruments that would be easy to install and maintain, " said Soren Nielsen, chief engineer at BornholmsTraffiken.

After visiting the vessel and conducting an assessment of the engine and burner systems, Mobrey Measurement suggested its 7829 Viscomaster viscometer.

Unlike capillary based viscometers, such as the ones that were originally used on the vessel, the Viscomasters have no moving parts. This, combined with the ability to perform self cleaning, provides a more reliable technology for this type of marine application.

"In the past, capillary based viscometers were the most common in HFO applications but we have seen significant developments in online viscometers, said Simon Wheeler, senior product manager at Mobrey Measurement. "The Viscomaster was the best choice for the Povl Anker . With fuel temperatures over 1000 and flow rates of 3 to 5m 3/hr it needed a robust reliable instrument. The Viscomaster was designed for this type of environment and is able to provide consistently accurate readings despite the harsh conditions."

The Mobrey Measurement Viscomaster uses vibrational fork technology, the principle of this being that a vibrating element is maintained in resonance whilst inserted into the liquid. The unit's response to the viscosity of the liquid is then calculated using a related measurement, the resonance width. This fork technology is unique in the viscosity instrumentation market as both the fluid viscosity and density are accurately and independently measured at the same time.

The four Viscomasters on the Povl Anker have now been in place for four months and engineers are pleased with their performance.

"We have been able to ensure a fixed kinematic viscosity of the fuel being delivered to the engines, said Nielsen. "This enables us to burn fuel more efficiently which has obvious environmental benefits."

Engineers also expect a reduction in maintenance related costs as a result of the installation.

MJ Information No: 21151