Turbomachine and method for disassembling such a turbomachine
A turbine includes an outer casing and an inner casing surrounded by said outer casing. The outer casing and inner casing are coaxially arranged with respect to a machine axis. The outer casing and inner casing are each divided in a split plane into an upper part and a lower part. The upper and lower parts are connected with each other in said split plane by means of a flanged connection. The disassembly process is improved by the flanged connection of the upper and lower part of the inner casing comprising a plurality of bolts, which extend each through through holes in respective flanges of said flanged connection of the inner casing, protrude from said through holes at both ends with a threaded section, and are tightened by means of nuts screwed on said threaded sections at both ends of said bolt.
1. A turbomachine configured to include an inner casing mounted to an outer casing when fully assembled, wherein in a state of disassembly the turbomachine comprising:
said inner casing having an upper part and a lower part with a first flanged connection including a first through hole, the upper part and lower part of the inner casing bearing a plurality of vanes;
a guide ring having a second flanged connection with a second through hole, wherein the first flanged connection of said inner casing is connected to the second flanged connection of the guide ring;
a plurality of bolts extending each through the first and second through holes in said first and second flanged connections respectively, wherein each bolt has threaded sections that protrude from the first and second flanged connections on each end and a shank that fully extends through said through holes such that the threaded sections protrude from said through holes, wherein said bolts are provided with screw heads at each end for rotationally fixing said bolts during disassembly; and
a pair of nuts secure each bolt to the first and second flanged connections via the threaded sections, wherein each nut in combination with a respective screw head provides means for disassembling the first and second flange connections, such that a rotationally fixed screw head allows untightening of at least one nut of the pair of nuts.
2. The turbomachine according to claim 1 , further comprising washers disposed between each nut and the first and second flanged connections.
3. The turbomachine according to claim 2 , wherein said bolts are designed as waisted shank bolts.
4. A method for disassembling a turbomachine including an inner casing having an upper part and a lower part divided in a split plane with a first flanged connection including a first through hole, the upper part and lower part of the inner casing bearing a plurality of vanes; a guide ring having a second flanged connection with a second through hole, wherein the first flanged connection of said inner casing is connected to the second flanged connection of the guide ring; a plurality of bolts extending each through the first and second through holes in said first and second flanged connections respectively, wherein each bolt has threaded sections that protrude from the first and second flanged connections on each end and a shank that fully extends through said through holes such that the threaded sections protrude from said through holes, wherein said bolts are provided with screw heads at each end for rotationally fixing said bolts during disassembly; and a pair of nuts secure each bolt to the first and second flanged connections via the threaded sections, wherein each nut in combination with a respective screw head provides means for disassembling the first and second flanged connections, such that a rotationally fixed screw head allows untightening of at least one nut of the pair of nuts, wherein when fully assembled an outer casing and said inner casing are coaxially arranged with respect to a machine axis, said outer casing is divided in the split plane into an upper part and a lower part, the method comprising:
demounting the upper part of the outer housing;
untightening the bolts of the first flanged connection of the inner casing at respective upper part ends by unscrewing respective nuts;
removing the upper part of the inner casing;
mounting the guide ring on the lower part of the inner casing to replace the upper part of the inner casing;
tightening the bolts of the first flanged connection of the inner casing at upper part ends to connect the second flanged connection of the guide ring to the lower part of the inner casing;
rotating an assembly of the lower part of the inner casing and the guide ring by 180° around the machine axis;
untightening the bolts of the first flanged connection of the inner casing at lower part ends by rotationally fixing each bolt via a respective screw head and unscrewing the respective nuts; and
removing the lower part of the inner casing.
5. The turbomachine according to claim 1 , wherein the first flanged connection of the inner casing is thicker than the second flanged connection of the guide ring.
6. The turbomachine according to claim 2 , wherein the washers are disposed in a recess of the second flanged connection.