Internal gear pump Model HD81EMR-1U2B2 - P/N 4509 HD: Heavy duty pump, Complete with motor on a common baseplate through flexible coupling 81: Pump size DN 80 - 3 " E: Suction/Discharge connection in-line M: Sealing with single mechanical shaft seal combined with a ball bearing as main bearing R: Safety valve, single acting for protection against excess pressure 1: Casing & cover: GG-25, Rotor/Idler: GG-25, Shaft: St.60.2 U: Idler bearing and main bearing lubricated by pump medium 2: Idler bush: Bronze, idler pin: Hardened 16 MnCr5 B: Bearing bush: Ball bearing, Shaft: St.60.2 2: Shaft seal: Single mechanical shaft seal Bellow type