... -centrifugal oil pump, S-first impeller double-suction,,material code of over-current partsI-class HT12547,-class ZG25,-class ZG1Cr13Ni.60, 150-single-stage ... .......Structure:AY-type oil pump has six models: single-stage single-suction cantilever type, double-stage single-suction cantilever type, single-stage double-suction cantilever ...