A LARGE TURBO BLOWER
Supplies Large Volume of Air at a Low Speed for Copper Smelting
What is perhaps the largest turbo blower yet constructed has now been in service for some time at Copper Cliff, Ont., at the plant of the International Nickel Co. The machine is driven by a self-starting synchronous motor, running at a speed of 1500 r.p.m. on 25 cycle 3 phase, alternating current.
The blower compresses 42,000 cu. ft. of air per min. to a pressure of 14lb per sq. in. The machine is equipped with a constant pressure or volume regulator, which causes the blower to deliver at a constant and adjustable pressure and which may be connected to deliver air at a constant and adjustable volume.
The exceedingly large size of the blower is due more to the low speed, 1500 r.p.m., than to the power of the machine, and if driven up to a speed for which it is amply strong it would have some 6000 or 7000-hp. capacity. As it is, when running at 1500 r.p.m., the machine absorbs approximately 2500 hp. The shipping weight is approximately 350,000 lb.
With this type of blower construction a stiff shaft is always employed, which never goes through the critical speed, and the impeller blades are mounted directly in "T" heads machined in the shaft forging. The impeller blades are robust in construction and taper rapidly to the periphery. In addition to the strength which this construction gives, no end thrust is developed within the blower, since there is a complete absence of longitudinal disks, against which any small air pressures could act to create end thrust. The entire impeller is located with reference to proper clearance to the casing by comparatively small thrust collars carried in one of the supporting journals. The row of large rectangular openings along the side of the blower casing gives access to the water cooling jacket, which completely encircles the air end casing.
The 2000-kw. motor which drives this unit can be started without taking from the line more than approximately its full load kva. rating and requires no auxiliary starting apparatus other than the usual auto transformers and switchboard equipment.
Both motor and blower bearings are lubricated with centrifugal oil pumps, directly connected to small motors, two of which are provided and continuously operated, while one pump alone is of ample capacity to supply the machine with lubricating and cooling oils.
-The Iron Age, February 13, 1919 P 429.