Active bypass flow control for a seal in a gas turbine engine

An active bypass flow control system for an outer balance seal, comprising:

• a stator assembly positioned in proximity to a first stage rotor whereby a compressed air channel is positioned between a portion of the stator assembly and a rotor shaft;
• at least one outer balance seal configured to at least reduce a portion of hot gases from flowing into a cooling cavity;
• at least one bypass channel extending from an inlet in fluid communication with the compressed air channel upstream of the at least one outer balance seal to an outlet in fluid communication with the compressed air channel downstream from the at least one outer balance seal;
• at least one metering device that is adjustable to adjust the flow of cooling fluids through the at least one bypass channel to accommodate a changing flow of compressed air past the at least one outer balance seal as the outer balance seal wears during turbine engine operation;
• and
• wherein the at least one metering device includes at least one valve formed from at least one pin movable between open and closed positions in which the at least one pin at least partially bisects the at least one bypass channel;
• wherein the at least one metering device further comprises at least one cam engaged to the at least one pin to move the at least one pin between open and closed positions;
• wherein the at least one cam is formed from a collar positioned in contact with a head of the at least one pin;
• and
• further comprising a sync ring in communication with the at least one pin via at least one valve arm extending from the at least one pin to the sync ring.

An active bypass flow control system for an outer balance seal, comprising:

• a stator assembly positioned in proximity to a first stage rotor whereby a compressed air channel is positioned between a portion of the stator assembly and a rotor shaft;
• at least one outer balance seal configured to at least reduce a portion of hot gases from flowing into a cooling cavity;
• at least one bypass channel extending from an inlet in fluid communication with the compressed air channel upstream of the at least one outer balance seal to an outlet in fluid communication with the compressed air channel downstream from the at least one outer balance seal;
• at least one metering device that is adjustable to adjust the flow of cooling fluids through the at least one bypass channel to accommodate a changing flow of compressed air past the at least one outer balance seal as the outer balance seal wears during turbine engine operation;
• wherein the at least one metering device includes at least one valve formed from at least one pin movable between open and closed positions in which the at least one pin at least partially bisects the at least one bypass channel;
• a sync ring in communication with the at least one pin via at least one valve arm extending from the at least one pin to the sync ring;
• wherein the at least one valve arm is pivotably attached to the sync ring;
• and
• at least one cam formed from a slot contained within the sync ring.