Centrifugal separator and rotor having an external hub to shaft connection

Patent metadata

Field	Value
Publication number	US-9616430-B2
Application number	US-201113637600-A
Country	US
Kind code	B2
Filing date	Mar 29, 2011
Priority date	Mar 31, 2010
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

The invention relates to a centrifugal separator for separation of at least two components of a fluid mixture which have different densities. The centrifugal separator comprises a rotor arranged for rotation about a vertical axis of rotation (R) and having a rotor wall which surrounds a separating chamber within the rotor, with an inlet adapted to feeding the fluid mixture into the rotor's separating chamber, and at least one outlet adapted to discharging outwardly from the rotor a component separated from the fluid mixture. A rotor shaft supports the rotor and is drivably connected to a motor (M) for rotation of the rotor about the axis of rotation (R). A hub is provided outside the rotor, and the hub and the rotor shaft are arranged to be connected together from the outside of the rotor by means of a lockable and releasable fastening which is configured to lock the rotor shaft relative to the hub in both a torque-transmitting and an axial force-transmitting way.

First claim

What is claimed is:

1. A centrifugal separator for separation of at least two components of a fluid mixture which are of different densities, which centrifugal separator comprises:
a rotor rotatable about an axis of rotation and comprising a rotor wall which surrounds an inner space with a separating chamber within the rotor, the rotor wall comprising a lower portion having a planar wall portion positioned on a bottom portion of the rotor,
an inlet for feeding the fluid mixture into the rotor's separating chamber,
at least one outlet for discharging out from the rotor a component separated from the fluid mixture,
a rotor shaft arranged to be connected to a hub on the rotor wall, the rotor being supported via the rotor shaft which is drivably connected to a motor for rotation of the rotor about the axis of rotation; and
the hub is situated outside the inner space of the rotor and has for the rotor shaft a connection directed axially outwards from the rotor, with a fastening so arranged at the side of the rotor wall which faces away from the inner space;
said fastening is a clamping device arranged to connect the hub to the rotor shaft in a releasable frictional fastening;
the hub is configured to radially surround a portion of the rotor shaft and an annular space is arranged radially between the hub and the rotor shaft, in which space said clamping device is slid axially into for frictional engagement with the hub and with the rotor shaft in the releasable frictional fastening between the clamping device, the hub and the rotor shaft;
the clamping device comprises a flange having an outer sleeve and an inner sleeve extending axially therefrom, the outer sleeve is expandable radially outwards and configured for frictional engagement with the hub, the inner sleeve is expandable radially inwards and configured for frictional engagement with the rotor shaft to lock the hub to the rotor shaft and the fastening is undone so that the clamping device, the rotor shaft and the rotor are released from one another; and
the hub extends axially downward from the planar wall portion a distance sufficient to receive the inner sleeve and the outer sleeve thereby terminating at an unobstructed axial end that engages a portion of the flange of the clamping device and the hub having unobstructed radially outward surfaces configured to provide access to the clamping device whereby the clamping device is operable from the outside of the rotor in order to releasably connect the hub to the rotor shaft.

2. A centrifugal separator according claim 1 , in which the rotor shaft and the hub are cylindrical.

3. A centrifugal separator according to claim 1 , in which the rotor shaft has running through it at least one axial duct adapted to have fluid flowing through it during operation of the centrifugal separator, and the hub comprises for said duct a duct connection which is arranged to communicate with the separating chamber via at least one fluid passage provided in the rotor.

4. A centrifugal separator according to claim 3 , in which said duct together with the duct connection and said fluid passage to the separating chamber form for said fluid a transfer path so configured that the fluid conveyed does not change direction by more than 100° relative to the axis of rotation (R).

5. A centrifugal separator according to claim 1 , in which the hub comprises an axial stop for the rotor shaft, in the form of an abutment surface with a radial extent, arranged to abut against the free end of the rotor shaft within the hub.

6. A centrifugal separator according to claim 1 , in which the hub comprises an axial stop for the clamping device, in the form of an abutment surface with a radial extent, arranged to abut against an end of the clamping device, which end is within the hub.

7. A centrifugal separator according to claim 1 , in which the separating chamber contains a stack of truncated conical separating discs, the hub is situated on an underside of the rotor, and the rotor shaft is oriented vertically and supports uppermost the rotor.

8. A centrifugal separator according to claim 1 , in which the rotor comprises outlet apertures peripherally in the rotor wall for discharge of a separated component in the form of sludge from the separating chamber, and an elastic sliding element is provided within the rotor to open and close said outlet apertures, which sliding element has a radially inner edge connected to, and axially fixed relative to, the rotor, and a radially outer edge portion which is axially movable relative to the rotor between open and closed states of the outlet aperture by elastic deformation of the sliding element.

9. A rotor for a centrifugal separator, the rotor comprising a rotor wall surrounding an inner space with a separating chamber within the rotor, the rotor wall comprising a lower portion having a planar wall portion positioned on a bottom portion of the rotor and the rotor comprising a hub arranged to be connected to a rotor shaft which is drivably connected to a motor for rotation of the rotor, wherein the hub is situated outside the inner space of the rotor, has for the rotor shaft a connection directed axially outwards from the rotor and is arranged to be connected with a fastening which is so arranged at the side of the rotor wall which faces away from the inner space;
said fastening is a clamping device arranged to connect the hub to the rotor shaft in a releasable frictional fastening;
the hub is configured to radially surround a portion of the rotor shaft and an annular space is arranged radially between the hub and the rotor shaft, in which space said clamping device is slid axially into for frictional engagement with the hub and with the rotor shaft in the releasable frictional fastening between the clamping device, the hub and the rotor shaft;
the clamping device comprises a flange having an outer sleeve and an inner sleeve extending axially therefrom, the outer sleeve is expandable radially outwards and configured for frictional engagement with the hub, the inner sleeve is expandable radially inwards and configured for frictional engagement with the rotor shaft to lock the hub to the rotor shaft and the fastening is undone so that the clamping device, the rotor shaft and the rotor are released from one another; and
the hub extends axially downward from the planar wall portion a distance sufficient to receive the inner sleeve and the outer sleeve thereby terminating at an unobstructed axial end that engages a portion of the flange of the clamping device and the hub having unobstructed radially outward surfaces configured to provide access to the clamping device whereby the clamping device is operable from the outside of the rotor in order to releasably connect the hub to the rotor shaft.

10. A centrifugal separator according to claim 3 , in which said duct together with the duct connection and said fluid passage to the separating chamber form for said fluid a transfer path so configured that the fluid conveyed does not change direction by more than 90° relative to the axis of rotation.

11. A centrifugal separator for separation of at least two components of a fluid mixture which are of different densities, which centrifugal separator comprises:
a rotor rotatable about an axis of rotation and comprising a rotor wall which surrounds an inner space with a separating chamber within the rotor, the rotor wall comprising a lower portion positioned on a bottom portion of the rotor, the lower portion having an inside surface and an outside surface spaced apart from one another by a predetermined distance,
an inlet for feeding the fluid mixture into the rotor's separating chamber,
at least one outlet for discha

Assignees

• Isaksson Roland
• Thorwid Peter
• Alfa Laval Corp Ab

Inventors

• Isaksson Roland
• Thorwid Peter

Classifications

• B04B7/08 Primary

  Rotary bowls (centrifugal casting machines B22D) · CPC title

• B04B1/14 Primary

  with periodical discharge · CPC title

• B04B2009/085

  Locking means between drive shaft and rotor · CPC title

• B04B9/08

  Arrangement or disposition of transmission gearing {(for solid bowl screw centrifuges B04B1/2016); Couplings; Brakes} · CPC title

• B04B1/08

  of conical shape · CPC title