Helium recovery helps fibre optic production

Thursday, 05 September, 2002



BOC's fibre optics solutions group has patented a helium recovery system capable of capturing and recycling more than 85% of the helium used in optical fibre production. This technology gives optical fibre producers greater control over their helium supply and product costs, and offers them a hedge against future price increases. Glenn Rush, vice president fibre optic solutions, says:

"Optical fibre producers need this technology today - even when production is slowed - because it can reduce their annual helium spend by 45-50% and help them through tough times. But they will need it even more in the future when production increases - in fact, it will be absolutely essential."

That's because helium is a critical element in the large-scale production of optical fibre. During its manufacture, fibre optic strands must be quickly cooled to prepare them for the application of a protective coating.

Only helium provides the cooling properties needed for high-speed, high-volume optical fibre production.

About 10% of all the helium currently produced is used in optical fibre manufacture, and that figure is conservatively expected to increase by about 25% a year once the current slowdown has run its course.

The problem for the optical fibre industry is that helium supply is not growing by anything near that rate, which puts pressure on helium prices and increases the cost of optical fibre production.

Helium is a by-product of natural gas production, and consequently, new sources are only developed when natural gas fields containing significant helium concentrations are developed. These are relatively uncommon. There are only 12 helium sources in the world, and some of these are nearing exhaustion.

The situation is even more troublesome for optical fibre producers in the Asia/Pacific market, because 85% of the world's supply of helium comes from sources in the US. The supply line to Asia/Pacific markets is extended and expensive.

"We want to protect our optical fibre users by providing the helium supply security they need to ramp up production," says Glenn.

The development of the helium recovery system is a significant advance for BOC and the fibre optic industry.

"Its value will become increasingly evident as the industry recovers from its recent slump and begins to increase production and, coincidently, helium demand."

Helium recovery

In the optical fibre draw process, the fibre passes through one or more cooling tubes where its temperature is lowered before the application of a protective coating. Helium gas is used in this process to enhance fibre cooling.

Since the thickness and the quality of the coating is dependent on the fibre temperature, helium is injected into the annular space between the fibre and the cooling tube at a flow rate necessary to achieve the required fibre temperature.

As the fibre draw speed is increased, proportionally more helium is introduced into the cooling tube to achieve the required temperature.

According to Igor Shedletsky, manager, commercial development, helium recovery, the helium recovery system reclaims helium molecules at greater than 99% purity from the pure helium gas used as a coolant in the fibre draw process.

The compact, modular helium recovery system contains all the necessary process equipment and control and monitoring hardware and software needed to reclaim helium molecules from a draw tower, and blend the reclaimed helium gas with virgin helium for recycling back to the draw tower at the required mass flow rate and helium purity level.

Each self-contained helium recovery module has its own operator interface terminal and is designed to work independently from other modules in the plant to ensure maximum helium recovery at all times.

Even if one or more towers are temporarily shut down, helium recovery continues uninterrupted at the other operating towers.

The modular units are designed for easy installation and low maintenance and feature a PC-based data highway hardware/software configuration that allows remote monitoring and troubleshooting of the entire process.

The key component of the recovery system is the helium collection collar mounted on top and/or at the bottom of each cooling tube.

The collar's unique design allows molecules that would otherwise be lost to the atmosphere as a result of gas dispersion to be reclaimed.

This device offers significant advantages over conventional methods of connecting the recovery system to the draw towers.

It maximises helium recovery rates and minimises atmospheric contamination regardless of the cooling gas flow rate.

How it works

The fibre optics solutions group is offering the helium recovery system to current and potential users as a standalone lease arrangement, or as part of a larger commodity supply contract.

In either case, it's a 'win-win' for the user, says Art Shirley, director of technology and commercialisation, fibre optics solutions.

"The lease arrangement is very beneficial for the optical fibre customer," Art says.

Under a lease arrangement, the user's capital outlay is minimal because there is no equipment to purchase. In addition, as part of the lease terms, we install and maintain the system, so there is no need for the customer to add new personnel or conduct extensive retraining of their present staff.

"Perhaps most important to the customer is the fact that, because we are managing the system and can remotely monitor its performance, we can guarantee the system's performance to standards set out in the lease terms."

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