Shaft support for supporting an agitator shaft and an agitator

Patent metadata

Field	Value
Publication number	US-12569818-B2
Application number	US-202017783412-A
Country	US
Kind code	B2
Filing date	Dec 9, 2020
Priority date	Dec 11, 2019
Publication date	Mar 10, 2026
Grant date	Mar 10, 2026

Abstract

The disclosure relates to a shaft support for supporting a lower portion of a rotatable shaft of an agitator configured to be installed in a tank, the shaft support comprising a support ring with an inwardly facing bearing surface configured to form a slide bearing journaling a lower portion of the rotatable shaft, wherein the bearing surface has a non-circular shape in a plane having a normal parallel to the shaft axis.

First claim

The invention claimed is:

1 . 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 and to be rotated about the shaft axis by the drive arrangement, and a shaft support for supporting a lower portion of the agitator shaft, the shaft support comprising:
a support ring extending around a central geometrical axis and being configured to circumscribe the lower portion of the agitator shaft, the support ring having an inwardly facing bearing surface configured to form a slide bearing journaling the lower portion of the agitator shaft,
the bearing surface having a non-circular shape, as seen in a projection in a plane having a normal parallel to the shaft axis, in the sense that a first distance, which is measured in a first direction in the plane and which forms a longest distance between the bearing surface and a circle representing an outer envelope surface of the agitator shaft is larger than a second distance, which is measured in a second direction in the plane and which forms a shortest distance between the bearing surface and the circle representing the outer envelope surface of the agitator shaft, the second distance being less than 70% of the first distance.

2 . The agitator according to claim 1 , wherein the non-circular shape of the bearing surface as seen in the plane having a normal parallel to the shaft axis, is at least partly provided by the support ring being tilted relative to the plane having a normal parallel to the shaft axis.

3 . The agitator according to claim 1 , wherein the bearing surface is formed as an ellipse as seen in a projection in the plane having a normal parallel to the shaft axis.

4 . The agitator according to claim 1 , wherein the bearing surface extends circularly around the central geometrical axis of the support ring.

5 . The agitator according to claim 1 , wherein the bearing surface has a convex cross-sectional shape, as seen in a radial plane extending radially from the central geometrical axis of the support ring, the bearing surface having a convex shape in the sense that a central portion of the bearing surface, as seen along the central geometrical axis, of the bearing surface bulges inwardly towards the central geometrical axis.

6 . The agitator according to claim 1 , wherein the support ring is made of metal.

7 . The agitator according to claim 1 , wherein the bearing surface is configured to allow the lower portion of the rotatable shaft to slidably move up and down relative to the bearing surface.

8 . The agitator according to claim 1 , the shaft support comprising a support structure configured to extend downwardly and to be attached to a bottom of a tank into which the rotatable shaft is intended to extend into.

9 . The agitator according to claim 8 , wherein the support structure is configured to be attached centred relative to a geometrical point where the shaft axis intersects the bottom of the tank.

10 . The agitator according to claim 1 , wherein the lower portion of the agitator shaft is provided with a bushing configured to interact with the bearing surface of the shaft support.

11 . The agitator according to claim 10 , wherein the bushing is composed of polymer-based or ceramic-based material.

12 . The agitator according to claim 10 , wherein the bushing is made of a material being softer than the material forming the bearing surface.

13 . The agitator according to claim 1 , wherein there is a radial play between the bearing surface and the lower portion of the agitator shaft.

14 . The agitator according to claim 13 , wherein the bearing surface defines a smallest geometrical cylinder of free space along the shaft axis, the smallest geometrical cylinder of free space having a diameter being larger than the diameter of the lower portion of the agitator shaft.

15 . The agitator according to claim 10 , wherein the bushing is composed of polymer-based or ceramic-based food grade material.

16 . The agitator according to claim 10 , wherein there is a radial play between the bearing surface and the bushing at the lower portion of the agitator shaft.

17 . The agitator according to claim 16 , wherein the bearing surface defines a smallest geometrical cylinder of free space along the shaft axis, the smallest geometrical cylinder of free space having a diameter being larger than the diameter of the bushing at the lower portion of the agitator shaft.

18 . The agitator according to claim 14 , wherein the smallest geometrical cylinder of free space has a diameter at least 5% larger than the diameter of the lower portion of the agitator shaft.

19 . The agitator according to claim 14 , wherein the smallest geometrical cylinder of free space has a diameter at least 1% larger than the diameter of the lower portion of the agitator shaft.

20 . A shaft in combination with a shaft support,
the shaft being a rotatable shaft that is rotatable about a shaft axis and that is configured to be connected to and extend downwardly from a drive arrangement for rotating the rotatable shaft about the shaft axis, the rotatable shaft having an outer envelope surface and including a lower portion; the shaft support supporting the lower portion of the rotatable shaft and including a support ring having an inwardly facing bearing surface that forms a slide bearing journaling the lower portion of the rotatable shaft, the inwardly facing bearing surface circumscribing the lower portion of the rotatable shaft and having a circular extension that extends circularly around a central geometrical axis of the support ring so that a distance from the central geometrical axis of the support ring to the bearing surface is equal in each point around the circular extension of the bearing surface in a first plane having a normal parallel to the central geometrical axis; and the support ring being in a tilted position relative to the rotatable shaft such that the support ring is tilted relative to a second plane having a normal parallel to the shaft axis such that the bearing surface has a non-circular shape as seen in a projection in the second plane, a first distance measured in a first direction in the second plane and being a longest distance between the bearing surface and the outer envelope surface of the shaft being larger than a second distance measured in a second direction in the second plane and being a shortest distance between the bearing surface and the outer envelope surface of the shaft, the second distance being less than 70% of the first distance.

21 . The shaft in combination with the shaft support according to claim 20 , further comprising at least one elongated rod having one end connected to the support ring and an opposite end configured to be connected to a bottom of a tank to hold the support ring in the tilted position.

22 . The shaft in combination with the shaft support according to claim 20 , further comprising a plurality of elongated rods each having one end connected to the support ring and an opposite end configured to be connected to a bottom of a tank to hold the support ring in the tilted position.

23 . The shaft in combination with the shaft support according to claim 22 , wherein each of the plurality of elongated rods has a different length.

24 . A shaft in combination with a

Assignees

• Alfa Laval Corp Ab

Inventors

• Bjerrisgaard Søren Thorøe

Classifications

• B01F2035/35

  Use of other general mechanical engineering elements in mixing devices · CPC title

• B01F2035/352

  Bearings · CPC title

• B01F27/90

  with paddles or arms · CPC title

• F16C2320/16

  Mixing apparatus · CPC title

• F16C17/028 Primary

  with fixed wedges to generate hydrodynamic pressure, e.g. multi-lobe bearings · CPC title