Hybrid multistage brush seal

A multi-stage brush seal assembly for sealing a circumferential gap with respect to a sealed component, the brush seal comprising:

• a housing configured to receive a first stage and a second stage;
• a first stage including a first plurality of bristles, the first plurality of bristles having free ends extending in a direction toward said sealed component;
• and
• a second stage including a second plurality of bristles, the second plurality of bristles having free ends extending in a direction toward said sealed component;
• wherein the first stage is configured with an initial first-stage clearance with respect to said sealed component and the first stage seals said sealed component at a high pressure and a low pressure condition;
• the second stage is configured to have an initial second-stage clearance with respect to said sealed component that is greater than the initial first-stage clearance so that the second stage does not seal said sealed component at the low pressure condition but is configured to be activated by a blow-down effect to seal said sealed component at the high pressure condition;
• a radial clearance is provided between the first plurality of bristles and a portion of the housing;
• and a radial clearance is provided between the second plurality of bristles and a portion of the housing.