Heat retention device for turbine casing, securing tool for securing heat retention block for turbine casing, and method for securing heat retention block for turbine casing

A method for securing a heat retention block for a turbine casing, the method comprising the steps of:

• installing a heat retention block on a turbine casing main body;
• adjusting a position of the heat retention block with respect to a socket disposed on a surface of the turbine casing main body, the socket having a hollow cylindrical shape centered on a socket axis, and the socket including an open end at an end on a first side in an axial direction where the socket axis extends;
• penetrating a securing rod including an engaging portion through the heat retention block;
• pressing the securing rod to fit the engaging portion within the socket;
• rotating the securing rod in a circumferential direction with respect to the socket axis;
• and
• engaging the engaging portion with the socket, wherein
• the heat retention block includes a bag body including an insertion hole formed in a predetermined position and inorganic fiber filled into the bag, and has a thickness from one surface side to another surface side,
• the securing rod includes a rod-shaped main body portion, and the engaging portion including a pair of protrusions formed on a first end of the main body portion and protruding outward in a radial direction with respect to the rod-shaped main body portion,
• the socket includes a first guide groove, a second guide groove, and a recessed groove recessed from an inner circumferential surface of the socket toward an outer circumferential side and formed so that the protrusion is inserted,
• the first guide groove includes a first starting end in the open end and a first terminal end, and extends in an axial direction from the first starting end to the first terminal end,
• the second guide groove includes a second starting end leading to the first terminal end and a second terminal end, and extends in a circumferential direction with respect to the socket axis from the second starting end to the second terminal end,
• the recessed groove leads to the second terminal end and extends in the axial direction from the second terminal end,
• in the step of installing, the other surface side of the heat retention block is brought into contact with a surface of the turbine casing main body,
• in the step of adjusting, the position of the heat retention block is adjusted to fit the socket into an insertion hole formed at a predetermined position on the other surface side of the heat retention block,
• in the step of pressing, the protrusion is inserted into the first guide groove from the first starting end of the first guide groove, and the securing rod is pressed to the first terminal end of the first guide groove,
• in the step of rotating, the protrusion in the first guide groove is inserted into the second guide groove from the second starting end of the second guide groove, and the securing rod is rotated in the circumferential direction to the second terminal end of the second guide groove, and
• in the step of engaging, the protrusion in the second guide groove is placed in the recessed groove.