Cooling system for turbine blade platforms

A cooling system for cooling platforms of turbine blades on a gas turbine rotor, the turbine rotor having a plurality of turbine blades extending from a periphery thereof, each turbine blade having an airfoil portion, a platform having longitudinal edges, a root portion affixed to the turbine rotor, and a shank portion connecting the root portion to the platform, adjacent turbine blades located such that a longitudinal edge of one platform is adjacent to a longitudinal edge of an adjacent platform so as to form a cavity bounded by a portion of the periphery of the turbine rotor, the shank portions of adjacent turbine blades and the platforms of adjacent turbine blades, the cooling system comprising:

• a) at least one cooling air supply passage to supply cooling air to the cavity;
• b) at least one cooling channel in a side of the platform facing the turbine rotor, the at least one cooling channel having a cooling air collector at an end located adjacent to the at least one cooling air supply passage and communicating with the cavity, and a plurality of venting holes passing through the other side of the platform, the venting holes being distributed along and communicating with the at least one cooling channel;
• and,
• c) a sealing plate extending across surfaces of adjacent platforms facing toward the turbine rotor so as to seal any gap between the adjacent longitudinal edges, and to cover the at least one cooling channel, the sealing plate having an orifice aligned with the cooling air collector of the at least one cooling channel enabling cooling air in the cavity to enter the at least one cooling channel and exit through the plurality of venting holes to thereby cool the platform.