| 摘要 |
A submersible positive displacement piston pump (10) includes a cylinder (12) for insertion within a body of liquid, the cylinder including a working end (14) and an opposite end (15), an inlet port (18), an outlet port (20) and a working chamber (26) bounded by the outlet port (20) and the working (14) end; a piston (28) rotatably and reciprocably movable in the cylinder (12) between a retracted position and an extended position for pumping liquid from the inlet port (18) to the outlet port (20), the piston including a free end (30) having a recessed section (34) alternately in fluid communication with the inlet port (18) and the outlet port (20), a pivoting assembly pivotally connected to a drive motor (36) which rotatably and reciprocably drives the piston (28) in the cylinder (12); and an extension assembly (60) for connecting the pivoting assembly to the piston (28) and for ensuring that the pivoting assembly and the drive motor (36) are positioned out of the body of liquid when the piston (28) and cylinder (12) are positioned in the body of liquid, the extension assembly including a shaft extension (60) for connecting the pivoting assembly to the piston, and a hollow extension pipe (66) surrounding the shaft extension (60) the extension pipe (66) being connected to the opposite end (15) of the cylinder (12) in a sealing relation and having an aperture (78) spaced slightly from the sealing connection for maintaining a liquid seal at the opposite end (15) of the cylinder (12) when the level of the body of liquid falls below the opposite end (15) of the cylinder (12). |
