THE BIGGEST N.Z. MADE BOILER

Press, Volume XCIX, Issue 29220, 2 June 1960, Page 20

THE BIGGEST N.Z. MADE BOILER

The largest steam-pressure boiler ever made in New Zealand came out of the annealing furnace at the Christchurch engineering firm of Andersons, Ltd., yesterday, and will soon be on its way to Timaru, where it will be installed at the Timaru Worsted and Woollen Company’s milt. Built to the firm’s own design, and to standards laid down by the British Standards Institute, the boiler has been 10 weeks in the making. It is of all-welded construction, and when completely fitted with combustion chamber, mechanical stoker, smokebox, and other parts, will be 21ft long and weigh about 20 tons.

The steam drum alone (shown in the photograph) i!s 16ft long, with a diameter of Bft, and weighs nine tons. The boiler will produce 80001 b of steam an hour—the largest evaporative capacity of any boiler yet New Zealand. It will be coal fired, and is the .first New Zealand-made “econo-mic-type” boiler to burn coal fuel.

The huge annealing furnace to temper the boiler drum and relieve welding stresses was specially designed for the job by the firm’s works engineer, Mr F. Van der Borch, and was being used for the first time. The boiler drum spent 14 hours in the furnace, being slowly heated up to 640 degrees Centigrade, at which stage it was red hot, and slowly allowed to cool. This process continued all Tuesday night, the boiler drum fin-

ally being removed from the annealing furnace about midday yesterday. The giant furnace has been designed to contain a boiler drum of up to 20,0001 b steam evaporation an hour, compared with the present boiler of 80001 b. Such a drum would itself weigh 24 tons.

The annealing furnace is made of steel plates covered with a heat-refracting substance made from one of New Zealand’s volcanic ashes. The roof is suspended on hangers to prevent it collapsing under the heat.

The shell of the boiler drum is built from fin boiler-quality steel plate, imported from England, and the end plates from liin plate, all welded. Before the drum is “fired” in the annealing furnace, every inch of welding is examined for possible defects by X-ray filming. x Strips of film are strapped round the drum over the welds, and the X-rays taken. The films are then painstakingly scrutinised for welding defects, which may appear as a minute speck on the film, so small that it escapes the layman’s eye.Any defective welding is taken out, and redone, after which it is again checked by X-ray filming.

About 350 ft of X-ray film was used in examining the welding of the huge boiler drum before it went into the annealing furnace on Tuesday afternoon.

Recipe for Longevity.—Mr Hui Chai-suen, a teetotaller and nonsmoker, claims that a short nap every afternoon is the key to longevity. He is 103.—Reuters.