Construction of Centrifugal Compressor
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Compressor Proper (Air end)
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Scroll : Circular and tubular casting widening its sectional areas toward rotating direction. Accommodates impeller in center portion of it. Form diffuser together with inlet. (vane less diffuser)
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Inlet : Covers scroll and impeller. Constructs compression chamber at rear side together with scroll. Form ventuli tube at front side. Makes air flow to impeller smooth.
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Diffuser: Vane less type: Space or area formed by inlet and scroll (in between tubular portion and outlet circumference of impeller).
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Impeller: Stainless casting machined to attain designed profile. Blade number is 16. Impeller are fitted at the end of pinion shafts.
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Pinion shaft : Drives impeller at specified speed. This compressor has two pinions arranged on both sides of the bull (wheel) gear. Gear ratio is as follows.
Bull gear speed is ..... r.p.m. , driving
Low speed pinion at ..... r.p.m. , and
high speed pinion at ..... r.p.m. ,
Low speed pinion is fitted two impellers at both ends, that is, 1st stage and 2nd stage impeller. High speed pinion is fitted 3rd stage is supported by tilting-pad type journal bearings at two points.
Thrust collars are fitted on both ends of gear meshing to the bull gear (thrust shoulder).