Clip-on crusaders

When super-massive 50-tonne trucks were about to hit the road a few years ago, some quick calculations showed that if they were to end up nose-to-tail and stationary on Auckland Harbour Bridge – not a totally unlikely scenario – the clip-on lanes could well collapse. Trucks were immediately banned from the outside lanes, and a tender was put out to strengthen the clip-ons with an estimated 350 tonnes of steel.

The then-small mechanical process engineering company in East Tamaki, Crusader Engineering, won the contract, and the number of hard hats in the factory tripled in two years. Over 900 tonnes of steel were needed, supplied as over 20,000 individually numbered pieces, and made to within incredibly tight tolerance limits of 0.25mm – the sort of precision that makes the thickness of a coat of paint critical. Fluctuating temperatures, plus traffic and wind force, can significantly expand and flex the steel, presenting all sorts of three-dimensional engineering difficulties.

The company spent $1 million gearing up for the job, and was given just a month following the successful tender to prove itself. The job has been completed and the trucks are now rolling.

Before the mammoth bridge project, Crusader Engineering built a medical waste sterilisation plant for Wellington. When overseas designers proved unable to supply the facility inside 18 months, Crusader rose to the challenge of designing, building and commissioning the plant within six months. They also solved some operational issues the client had with previously imported designs.

The company’s main business, however, is still timber treatment processing. Their process allows the timber to be treated after it is machined to its final shape and form, and no chemically contaminated sawdust is generated. The addition of a water repellent improves stability and quality – attributes New Zealanders will be mindful of after the appalling misery suffered by leaky home owners.

Crusader’s big advantage is its ability to remove and recover the solvent, eliminating the health risks of volatile organic compounds. The team use radio frequency technology to drive off the solvent, which can then be re-used, with obvious economic benefits.

And the product can be ready for market and out of the factory much faster, reducing storage time and space. The company, which is eager to export this dramatically improved process, has a large pilot plant in the US. IRL chemical engineers Drs Stephen Tallon, Peter Dyer and Wayne Eltringham are working with Crusader’s designers to make this plant as efficient as possible.

There are exciting possibilities ahead. The principle of using radio frequency radiation has potential applications to all sorts of other processes, such as drying animal feed.

Managing director Peter Snoad and business development manager Craig Apps say they like nothing better than to prove people wrong when they say something can’t be done. They attribute their problem-solving success to the cross-pollination of diverse engineering backgrounds they have on staff ("old heads and young stars"). And the company is still small enough, says Craig, that everyone can have a voice, and feel that their opinion really counts.