EVANS BAY POWERHOUSE

Dominion, Volume 30, Issue 254, 23 July 1937, Page 10

EVANS BAY POWERHOUSE

First Velox Boiler in Use At the Evans Bay power-house during the past week the new type of Swiss boiler known as the Velox, to which is coupled a Parsons 15,000 k.w. turbo-generator, has been “taking the load” for three or four hours each evening, and such is the economy effected that even when there is full pressure not the slightest wisp of steam or smoke can be seen emerging from the stack. The boiler is oil-fed, with a single jet, which sprays in crude oil with a steady, even flow that ensures perfect combustion. It is possible to attain full pressure of steam from cold in between five to six minutes, whereas with the old water-tube boilers over half an hour elapsed before full pressure could be assured. But the most important feature about the Velox is its economy. The usual standard boiler when it is in first-class condition, may give up to 85 per cent, efficiency, but the Velox only wastes about 6 per cent, of the steam —its efficiency is about 94 per cent. It is the velocity of" the gases m the combustion chamber that gives the Velox boiler its speed—hence the name. The combustion chamber is surrounded by a battery of evaporator tubes, with still more complicated tubes within them. From those inner tubes the steam passes to the tubular super-heater, round which the furnace gases swirl at an amazing velocity. The gases then pass on to operate a gasturbine blower, which creates pressure for the forced draught of the combustion chamber. Without losing temperature to any extent the gases pass on. to super-heat the water that is being pumped into the evaporator tubes that line the combustion chamber. Mr. F. T. M. Kissel, the Government electrical engineer, paid a visit to the Evans Bay power-house on Wednesday, and witnessed the new boiler under steam pressure. The second Swiss boiler will not be ready for testing until about this time flext month.