Patent attributes
The invention relates to a pump for pumping contaminated liquid including solid matter, comprising an impeller (1), which is rotatable in a pump chamber of said pump, the impeller (1) being movable in the axial direction in relation to a seal housing cover (3) between a first position adjacent to an impeller seat (2) and a second position spaced apart from said impeller seat (2), said pump also comprising a cavity (17) defined by the seal housing cover (3) and the impeller (1), and at least one opening gap (20) connecting said cavity and said pump chamber. Furthermore, said opening gap (20) has a first flow area when the impeller (1) is in the first position, and a second flow area bigger than said first flow area when the impeller (1) is' spaced apart from said first position.
