A turbine blade of an axial turbine includes internal cooling fluid passages with radially outwardly extending passages connected to holes in the blade root. The holes are generally core printouts providing stability to the core during the casting process, but are not needed and need to be closed to guarantee the functioning of the cooling system. This is achieved by at least one covering plate. The plate is held by at least two slots located at the root of the turbine blade. Thus, the supply holes for cooling fluid located at the root section are closed by a simple mechanical device, e.g., a plate that does not require any subsequent brazing/welding operations. In addition, the plate is removable to facilitate inspection/cleaning, or further processing of the blade at service intervals.
1. A turbine blade of an axial turbine, the blade comprising:
a blade root having a slot and holes therein;
a blade body having internal passages with radially outwardly extending passages connected to the blade root holes; and
a plate covering at least one of the blade root holes, the plate being held in the blade root slot and being slideably moveable in and removeable from the slot, wherein the slot is a through-going slot having a respective opening on each of two opposed sides of the turbine blade root.
2. The turbine blade of an axial turbine according to claim 1 , wherein the slot is machined in a thickened portion of the root area.
3. The turbine blade of an axial turbine according to claim 1 , wherein the plate comprises an orifice hole.
4. The turbine blade of an axial turbine according to claim 1 , wherein the blade root has a fir tree root section.
5. The turbine blade of an axial turbine according to claim 1 , wherein the plate is made from a heat resisting alloy manufactured from a sheet material.
6. An axial turbine, comprising:
the turbine blade according to claim 1 , and a turbine rotor having flanks, wherein the plate is removably secured by the turbine rotor flanks.