Abstract:
A five-part rotor assembly is easily disassembled for cleaning and/or sterilization. The five parts comprise a rotor sleeve, a rotor head, a weir plate, a rotor cover and an internal vane package. Each of these parts is machined as a unitary piece or otherwise fabricated without weldments.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to the field of centrifugal separators for separating liquids of different densities and, more particularly, to a non-welded, easily disassembled rotor assembly for such separators. 
     2. Prior Art 
     Centrifugal devices are widely used for separating materials of different densities. Such devices have been found to provide a highly satisfactory method of separating mixed liquids from one another, provided that the liquid components have different densities. Conventional centrifugal separators employ a complex rotor structure to mix and separate the component phases. Typically, the various parts of the rotor assembly are welded together. Such welded construction has certain disadvantages in some fields of use. 
     Medical and pharmaceutical applications have very stringent cleanliness requirements. Conventional welded rotor assemblies are not suitable for such applications. First of all, a welded structure cannot be readily disassembled for cleaning or sterilization. Secondly, in order to comply with good manufacturing practices established for medical and pharmaceutical applications, all welds would need to be ground and polished, thereby complicating the fabrication process. 
     A need therefore exists for a centrifugal separator rotor assembly that is free of weldments and can be easily disassembled. 
     SUMMARY OF THE INVENTION 
     The present invention comprises a five-part rotor assembly that can be easily disassembled for cleaning and/or sterilization. The five parts comprise a rotor sleeve, a rotor head, a weir plate, a rotor cover and an internal vane package. Each of these parts is machined as a unitary piece or otherwise fabricated without weldments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view of the rotor assembly of the present invention. 
     FIG. 2 is a top plan view of the rotor head. 
     FIG. 3 is a side elevation view of the rotor head. 
     FIG. 4 is a bottom plan view of the rotor head. 
     FIG. 5 is a cross-sectional view of the rotor head taken through line  5 — 5  of FIG.  4 . 
     FIG. 6 is a cross-sectional view of the rotor sleeve. 
     FIG. 7 is a side elevation view of the vane package. 
     FIG. 8 is a top plan view of the vane package. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following description, for purposes of explanation and not limitation, specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known methods and devices are omitted so as to not obscure the description of the present invention with unnecessary detail. 
     FIG. 1 is an exploded view illustrating a rotor assembly  10  in accordance with the present invention. The principal components of the rotor assembly are the rotor sleeve  12 , the rotor head  14  and the rotor vane package  16 . The vane package fits within the rotor sleeve and is retained therein by the rotor head, which threads onto the rotor sleeve. Weir plate  18  is held in place on the top of the rotor head by rotor cover  20 . Rotor cover  20  is secured by a seal ring (not shown) which goes over shaft  40 . A bearing assembly (also not shown), which is attached to shaft  40 , effectively sandwiches the seal ring, rotor cover  20  and weir plate  18 . O-ring  22  ensures a fluid-tight seal between weir plate  18  and rotor head  14 . A second O-ring  24  ensures a fluidtight seal between rotor sleeve  12  and rotor head  14 . 
     FIGS. 2-5 illustrate the detailed construction of rotor head  14 . During operation of the separator, lighter phase components enter slinger  30  through central aperture  32  and exit radially through slots  34 . Heavier phase components bypass slinger  30  through slots  36 . The higher density components exit rotor head  14  through aperture  19  in weir plate  18 . 
     Rotor head  14  includes shaft  40  which is supported within the separator housing by bearings (not shown) and couples to a motor (also not shown) for rotation of the entire rotor assembly  10 . In the exemplary embodiment illustrated and described herein, the separator is of a suspended rotor design. However, the invention is also applicable to separators having rotors with lower support shafts. Rotor head  14  is internally threaded at  42  for mating engagement with the rotor sleeve. An annular channel  43  is provided to receive O-ring  22 . 
     In a preferred embodiment, rotor head  14  is machined from a unitary piece of material so as to avoid any weldments or other joints. The particular material will be selected for compatibility with the process chemicals and may include, for example, various stainless steel or aluminum alloys or composite materials. 
     FIG. 6 is a cross-section view of rotor sleeve  12 . The rotor sleeve is a hollow can-like structure with an aperture  44  in the bottom thereof through which the mixed components are admitted for separation. External threads  46  are provided for mating engagement with rotor head  14  as mentioned above. Channel  48  is provided to receive O-ring  24 . 
     Rotor sleeve  12  is preferably spun and/or machined from a unitary piece of material. As with the rotor head, the rotor sleeve will be made of a material selected for compatibility with the intended process and will typically be made of the same material as the rotor head. 
     FIGS. 7 and 8 illustrate vane package  16 . In the illustrated embodiment, the vane package comprises four vanes  50 ; however, different numbers of vanes may be used if desired. Weld spots or other similar means may be provided on the inside wall of rotor sleeve  12  to prevent rotation of vane package  16  during operation of the separator. Vane package  16  includes diverter plate  52  proximate to the bottom of vanes  50 . Vanes  50  are notched both at  54  and  56 . These notches, in combination with diverter plate  52 , help to distribute the input component stream within the rotor. 
     It will be recognized that the above described invention may be embodied in other specific forms without departing from the spirit or essential characteristics of the disclosure. Thus, it is understood that the invention is not to be limited by the foregoing illustrative details, but rather is to be defined by the appended claims.