Radial centrifugal turbomachine

Abstract

A radial centrifugal turbomachine with an adjusting device operatively active at the axial inlet of the turbomachine fixed casing, including: an annular member delimiting at least one radially inner passage at the axial inlet, wherein the member front surface and abutment surface of the casing delimit a radial annular passage. An actuator is connected to the member and to move axially and/or rotate according to a predefined angle to vary the radial annular passage and/or passage sections delimited between stator blades of the turbomachine first radial stage. A transmission shaft coaxial with the rotation axis and integral with the member is operatively connected to the actuator. The adjusting device allows adjusting the mass flow rate at the inlet to better adapt the performances of the turbomachine to the loading of the process/cycle and to implement a safety system dedicated to stopping the turbomachine in case of an urgent stop request.

1 - 18 . (canceled) 
     
     
         19 . A radial centrifugal turbomachine, comprising:
 a fixed casing;   a rotor disc installed in the casing and rotatable in the casing around a respective rotation axis;   a ring of rotor blades mounted on a front face of the rotor disc and coaxial with the rotation axis, in which the rotor blades project axially from the front face of the rotor disc;   a ring of stator blades, radially inner and concentric with respect to the ring of rotor blades, in which the stator blades extend axially between the casing and the front face of the rotor disc, in which the stator blades delimit between them passage sections;   wherein the casing has an axial inlet that is radially inner with respect to the ring of stator blades;   an adjusting device operatively active at the axial inlet;   in which the adjusting device comprises:
 an annular member delimiting at least one radially inner passage for the fluid, the annular member being located at the axial inlet, in which a front surface of the annular member and an abutment surface of the casing delimit between them a radial annular passage; 
 at least one actuator connected to the annular member and configured to move axially and/or to rotate around the rotation axis, according to a predefined angle, the annular member so as to vary the radial annular passage and/or the passage sections; 
 a transmission shaft coaxial with the rotation axis, integral with the annular member and operatively connected to the actuator. 
   
     
     
         20 . The turbomachine of  claim 19 , wherein the annular member is movable both in rotation and axially upon command of an axial and rotation actuator. 
     
     
         21 . The turbomachine of  claim 19 , wherein the annular member is movable axially up to a closed configuration for blocking the flow of fluid through the turbomachine, wherein, in the closed configuration, the front surface of the annular member lies against the abutment surface of the casing and the radial annular passage is closed. 
     
     
         22 . The turbomachine of  claim 21 , wherein the annular member is movable between a configuration a) of complete opening of the radial annular passage, in which the front surface of the annular member lies at a maximum distance from the abutment surface of the casing, and the closed configuration b). 
     
     
         23 . The turbomachine of  claim 22 , wherein the annular member can be stopped in any intermediate position c) between the configuration a) of complete opening and the closed configuration b). 
     
     
         24 . The turbomachine of  claim 21 , wherein the adjusting device incorporates a safety device configured to bring the annular member into the closed configuration in case of emergency. 
     
     
         25 . The turbomachine of  claim 24 , wherein the safety device comprises elastic means configured to push the annular member towards the abutment surface and into the closed configuration; wherein the actuator acts axially in opposition to the elastic means. 
     
     
         26 . The turbomachine of  claim 25 , wherein the elastic means are pre-loaded. 
     
     
         27 . The turbomachine of  claim 25 , wherein the actuator is single-acting and moves the annular member away from the abutment surface of the casing and towards the configuration of complete opening, opposing the elastic means. 
     
     
         28 . The turbomachine of  claim 25 , wherein the elastic means are configured to bring the annular member into the closed configuration in a closing time comprised between 0.02 s and 0.1 s. 
     
     
         29 . The turbomachine of  claim 19 , wherein the annular member has a diverging surface that delimits the radially inner passage. 
     
     
         30 . The turbomachine of  claim 19 , wherein the adjusting device comprises radial elements which connect the annular member to the transmission shaft. 
     
     
         31 . The turbomachine of  claim 19 , wherein the adjusting device comprises a guide element integral with the casing, coaxial with the rotation axis and slidably engaged with the transmission shaft. 
     
     
         32 . The turbomachine of  claim 31 , wherein the guide element is engaged with a distal end of the transmission shaft, in which between the shaft and the guide element, a small chamber with variable volume is delimited, in which the guide element and/or the shaft have vent channels in fluid communication with the small chamber with variable volume. 
     
     
         33 . The turbomachine of  claim 19 , wherein the annular member has a plurality of through slits, in which each of the stator blades is inserted in and slidably coupled with one of the through slits, in which the axial movement of the annular member involves a height variation of the stator blades and of the passage sections between the stator blades. 
     
     
         34 . The turbomachine of  claim 19 , wherein the annular member can be rotated around the rotation axis according to a predefined angle upon command of the actuator; wherein each of the stator blades can be oriented around a respective adjustment axis parallel to the rotation axis and is operatively connected to the annular member; wherein a rotation of the annular member involves a synchronized orientation of the stator blades around the respective adjustment axes and a variation of the passage sections delimited between the stator blades. 
     
     
         35 . The turbomachine of  claim 19 , wherein the adjusting device comprises a transmission ring coaxial with the rotation axis and radially outer with respect to the radially inner passage of the annular member; wherein the transmission ring is axially fixed with respect to the casing and is movable in rotation with respect to the casing together with the annular member; wherein the transmission ring is connected to each of the stator blades at points spaced from the respective adjustment axes. 
     
     
         36 . The turbomachine of  claim 19 , wherein the casing comprises an inlet duct mounted on the axial inlet, wherein the transmission shaft is at least partly housed within the inlet duct, wherein the axial actuator and/or the rotation actuator are connected to the transmission shaft at a proximal end, opposite the distal end of the transmission shaft, which exits outward from the inlet duct.