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Roller chain proves worth at Scottish Water

Edited by the Engineeringtalk editorial team Jan 20, 2006

Engineers from Scottish Water were having to replace standard carbon steel roller chain every few months at the Dalmarnock sewage treatment works until they tried corrosion resistant DP chain.

Engineers from Scottish Water were having to replace standard carbon steel roller chain every few months at the Dalmarnock sewage treatment works until it was suggested that they try corrosion resistant DP chain from Tsubaki.

The outdoors environment and difficult lubricating conditions had caused heavy corrosion and stretching in the standard chains and led to the frequent failures.

The replacement chain from Tsubaki has already completed twice the wear life of standard chain and is still going strong while showing no signs of corrosion or elongation.

The drive chains employed at Dalmarnock are large 3.6m sections of 2.54cm pitch pitch fitted in duplex sets, they drive under constant load and so have a high kW power rating.

The high load meant that other corrosion resistant chain materials such as stainless steel were unsuitable because of their lower strength.

Tsubaki DP Chain however, uses an advanced metal coating process to protect the chain from corrosion and retains the same strength characteristics as high quality carbon steel roller chain.

DP Chain therefore provided a direct replacement for the standard carbon steel roller chain, requiring no derating of input power or change of sprockets and drive train.

Tsubaki Sales Engineer Don Elliot commented: "Tsubaki DP chain provided an ideal solution and as the purchase price is only 10-15% higher than standard carbon steel roller chain, it has already paid for itself in terms of replacement cost".

"We are committed to helping customers reduce costs and improve efficiency wherever we can; this application provided us with an obvious challenge to find a better alternative".

"As the old chain is phased out on the site, downtime caused by failures and the amount of maintenance time taken to fit replacements will be reduced substantially".

In tests, DP treated chain has endured salt-water (brine) spray for more than 500 hours, providing five times the anticorrosion performance of zinc-plated chain and 20 times the performance of nickel-plated types.

The coating process for DP chain involves "double plating", first by galvanising the metal and then surface treating it with a special coating to protect against corrosive environments.

The coating does not reduce chain strength, but adds a tough protective shell that guards against surface scratches.

The process produces a smooth and consistent surface finish, maximising resistance to wear.

"This product could make a significant impact on maintenance for the UK water processing industry", claims Elliot.

"Roller chain from a variety of manufacturers had failed in this application and conditions similar to Dalmarnock exist in many other water processing sites".

"Equipment is exposed to the elements and is geographically remote, making lubricating the chains an awkward and time consuming task".

"This is particularly true of the 371 Scottish Water treatment sites that process over 1 billion litres of waste water per day, but are spread over an area of 78,000 square kilometres - a third of the area of Britain".

"There are 24 sets of duplex chains at the Dalmarnock site alone, making the potential savings substantial".

DP chain is available in both roller and conveyor versions.

Its superior corrosion performance, including resistance to acid rain and other adverse weather conditions, makes it extremely reliable for outdoor use.

The chain has been used on equipment as large as vertical parking systems and is ideal for other outdoor applications such as seafood processing machines, car washers, case washers and dockside handling equipment.