Hydrodynamic brush seal

Abstract

A hybrid brush seal is provided having two bundles of axially spaced seal bristles each of which are mounted in a ring shape on a first machine component with bristle ends directed at a sealing surface of the second, rotating machine component. The bristle ends are kept from direct contact with the rotating machine component via one or more shoes which are designed such that as the shaft rotates a hydrodynamic film separates the shoe(s) from the shaft. The shoe(s) is attached to the bristle ends at discreet locations. Alternatively, one or more bundles of seal bristles are mounted at one end either to the fixed or rotating machine component, with the opposite bristle ends directed toward one or more shoes, and wherein one or more spring elements are connected between the machine component and shoes.

1 . A brush seal for sealing a circumferential gap between a first machine component and a second machine component which is rotatable relative to the first machine component about a longitudinal axis, comprising: 
 a first bundle of seal bristles each having a first end and a second end, said first ends of said first bundle of seal bristles being mounted to one end of said first and second machine components and said second ends thereof extending in a direction toward the other of said first and second machine components;    a second bundle of seal bristles each having a first end and a second end, said first ends of said second bundle of seal bristles being mounted to one of said first and second machine components and said second ends thereof extending in a direction toward the other of such first and second machine components, said second bundle of seal bristles being axially spaced from said first bundle of seal bristles;    at least one shoe extending about whichever one of the first or second, machine components is located opposite said first ends of said seal bristles, said at least one shoe being fixed to said second ends of each of said first bundle and said second bundle of seal bristles in at least one location there along to substantially prevent relative movement between said at least one shoe and said second ends and so that said seal bristles do not directly contact either of the first and second machine components.    
   
   
       2 . The brush seal of  claim 1  in which said first ends of said first bundle of seal bristles and said first ends of said second bundle of seal bristles are mounted to the first machine component.  
   
   
       3 . The brush seal of  claim 1  in which said second ends of said first bundle of seal bristles and said second ends of said second bundle of seal bristles extend in a direction toward the second machine component.  
   
   
       4 . The brush seal of  claim 1  further including a high pressure backing plate; a low pressure backing plate and at least one spacer plate located between said high and low pressure backing plates, said first group of seal bristles being located between said high pressure backing plate and said at least one spacer plate and said second group of seal bristles being located between said at least one spacer plate and said low pressure backing plate.  
   
   
       5 . The brush seal of  claim 1  in which said at least one shoe is formed with a flow path for balancing static pressure.  
   
   
       6 - 18 . (canceled)