Patent ID: 7354009
Filing Date: 2008-04-08
Classification: F04D,H02K

Abstract:
1. A sewage pump comprising: a motor providing power; a main shaft penetrating the motor and having a top end combined with an upper impeller and a bottom end combined with a lower impeller and a grinding wheel; a top cap forming a zenith and having an upper inlet and an upper outlet; an upper bearing with an upper mounting plate that combines with the top cap and peripherally contacts the main shaft, with the upper mounting plate and the top cap forming an upper impeller chamber surrounding the top end and the upper impeller; an upper bearing base peripherally contacting the main shaft and attached under the upper mounting plate on the upper bearing, with the upper bearing, the upper bearing base, and the upper mounting plate providing an upper seal chamber in fluid isolation and sealed against pressure from the upper impeller chamber; a tube body hermetically engaged under the upper bearing base, having a side face and a protrusion tube extending from the side face, surrounding the motor and combining with a wire inlet connector; a lower bearing base peripherally contacting the main shaft and hermetically engaged under the tube body; a lower bearing peripherally contacting the main shaft and having a lower mounting plate attached to the lower bearing base, with the lower bearing, the lower bearing base, and the lower mounting plate providing a lower seal chamber, with the motor intermediate the lower seal chamber and the upper seal chamber axially along the main shaft, and with the motor in isolation from the upper seal chamber and the lower seal chamber; a lower base attached under the lower mounting plate on the lower bearing and having a lower inlet and a lower outlet, with the lower mounting plate and the lower base forming a lower impeller chamber surrounding the bottom end and the lower impeller, with the lower seal chamber in fluid isolation and sealed against pressure from the lower impeller chamber; and a vertical bypass communicated between the lower outlet on the lower base and the upper inlet on the top cap; wherein: the upper bearing and the upper mounting plate form a first bearing portion, the upper bearing base forms a second bearing portion axially spaced along the main shaft from the first bearing portion and on an opposite side of the upper seal chamber, the lower bearing base forms a third bearing portion, and the lower bearing and the lower mounting plate form a fourth bearing portion axially spaced along the main shaft from the third bearing portion and on an opposed side of the lower seal chamber, with the bearing portions providing a quad-bearing structure supporting the main shaft to make the sewage pump stable and durable at high speed operation; and the upper bearing and the upper mounting plate form a first rotary seal sealing the main shaft against pressure from the upper impeller chamber, the upper bearing base forms a second rotary seal axially spaced from the first rotary seal along the main shaft and on the opposite side of the upper seal chamber and sealing the upper chamber from the motor, the lower bearing base forms a third rotary seal sealing the lower seal chamber from the motor, and the lower bearing and the lower mounting plate form a fourth rotary seal axially spaced from the third rotary seal along the main shaft and on the opposed side of the lower seal chamber sealing the main shaft against pressure from the lower impeller chamber to make the sewage pump hermetical.