An agitator configured to be installed in a tank, the agitator comprising a drive arrangement , an agitator shaft being provided with agitator blades and being configured to extend downwardly from the drive arrangement along a shaft axis (L) and to be rotated about the shaft axis (L) by the drive arrangement , and a shaft support for supporting a lower portion of the rotatable shaft , the shaft support comprising: a support ring extending around a central geometrical axis (C) and being configured to circumscribe the lower portion of the rotatable shaft , the support ring having an inwardly facing bearing surface configured to form a slide bearing journaling the lower portion of the rotatable shaft , characterized in that the bearing surface has a non-circular shape, as seen in a projection in a plane (P) having a normal parallel to the shaft axis (L), in the sense that a first distance (d 1 ), which is measured in a first direction (A) in the plane (P) and which forms a longest distance between the bearing surface and a circle representing an outer envelope surface of the shaft is larger than a second distance (d 2 ), which is measured in a second direction (B) in the plane (P) and which forms a shortest distance between the bearing surface and the circle representing the outer envelope surface of the shaft , wherein the second distance (d 2 ) is less than 70% of the first distance (d 1 ). a drive arrangement , an agitator shaft being provided with agitator blades and being configured to extend downwardly from the drive arrangement along a shaft axis (L) and to be rotated about the shaft axis (L) by the drive arrangement , and a shaft support for supporting a lower portion of the rotatable shaft , the shaft support comprising: a support ring extending around a central geometrical axis (C) and being configured to circumscribe the lower portion of the rotatable shaft , the support ring having an inwardly facing bearing surface configured to form a slide bearing journaling the lower portion of the rotatable shaft , characterized in that the bearing surface has a non-circular shape, as seen in a projection in a plane (P) having a normal parallel to the shaft axis (L), in the sense that a first distance (d 1 ), which is measured in a first direction (A) in the plane (P) and which forms a longest distance between the bearing surface and a circle representing an outer envelope surface of the shaft is larger than a second distance (d 2 ), which is measured in a second direction (B) in the plane (P) and which forms a shortest distance between the bearing surface and the circle representing the outer envelope surface of the shaft , wherein the second distance (d 2 ) is less than 70% of the first distance (d 1 ). a support ring extending around a central geometrical axis (C) and being configured to circumscribe the lower portion of the rotatable shaft , the support ring having an inwardly facing bearing surface configured to form a slide bearing journaling the lower portion of the rotatable shaft , characterized in that the bearing surface has a non-circular shape, as seen in a projection in a plane (P) having a normal parallel to the shaft axis (L), in the sense that a first distance (d 1 ), which is measured in a first direction (A) in the plane (P) and which forms a longest distance between the bearing surface and a circle representing an outer envelope surface of the shaft is larger than a second distance (d 2 ), which is measured in a second direction (B) in the plane (P) and which forms a shortest distance between the bearing surface and the circle representing the outer envelope surface of the shaft , wherein the second distance (d 2 ) is less than 70% of the first distance (d 1 ). <EOS>