Abstract:
A valve for a turbomachine, has a valve cone and a valve seat, the valve cone being configured such that it can be moved in a valve body with respect to the valve seat. The opening and closing of the valve being achieved by the use of process-internal media taking into account different geometries of the working chambers and the use of thermodynamically different state variables.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is the US National Stage of International Application No. PCT/EP2014/064160 filed Jul. 3, 2014, and claims the benefit thereof. The International Application claims the benefit of European Application No. EP13177934 filed Jul. 25, 2013. All of the applications are incorporated by reference herein in their entirety. 
     
    
     FIELD OF INVENTION 
       [0002]    The invention relates to a valve for a turbomachine, in particular steam turbine, having a valve cone and a valve seat, the valve cone being configured such that it can be moved in a valve body with respect to the valve seat. 
       BACKGROUND OF INVENTION 
       [0003]    Valves for turbomachines, in particular steam turbines, are given special significance, since the feed of steam to a steam turbine has to have substantially two properties. These would be firstly regulating the steam which flows into the steam turbine and, in the case of a disruption of the quick-action closure of the valve, in order to interrupt the feed of steam. There are embodiments of valves, in which said two properties are arranged in a single valve housing. On account of the high temperatures and the high pressures of the steam, the technical requirements of valves of this type are particularly high. The opening and closing at high temperatures and high pressures prove difficult. As a rule, a valve cone has to be configured in valves such that it can be moved in one direction. The forces for being able to move said valve cone are comparatively high and are either of hydraulic or electrohydraulic configuration. 
         [0004]    Furthermore, the valves have to be configured in such a way, for reasons of safety, that a fault or a failure of the actuation leads to automatic closure of the valves (“valve closed” safety position). 
       SUMMARY OF INVENTION 
       [0005]    It is an object of the invention to specify an alternative possibility for moving a valve cone against the valve seat. This object is achieved by way of a valve for a turbomachine, in particular steam turbine, having a valve cone and a valve seat, the valve cone being configured such that it can be moved in a valve body with respect to the valve seat, the valve body having a first pressure space which is configured in such a way that, in the case of loading in the first pressure space at the pressure p 1  the valve cone moves in the direction of the valve seat, the valve body having a second pressure space which is configured in such a way that, in the case of loading in the second pressure space at the pressure p 1  the valve cone moves in the opposite direction of the valve seat. 
         [0006]    As viewed in the movement direction of the valve cone, the first pressure space is configured in such a way that it has a projected effective first pressure area A 1 , the second pressure space having a projected effective second pressure area A 2 , as viewed in the movement direction of the valve cone, wherein: A 1 &lt;A 2 . 
         [0007]    As a result, the force which is built up via the pressure on the two pressure areas is of different magnitude, with the result that finally a movement of the valve cone is possible. 
         [0008]    According to the invention, the opening and closure of the valve is therefore made possible by way of the use of process-internal media with consideration of various geometries of the working spaces and the use of thermodynamically differentiated state variables. Here, in particular, the first pressure space is loaded at a pressure p 1  the pressure p 1  being formed by way of the inflowing flow medium, steam in this case. 
         [0009]    Advantageous developments are specified in the subclaims. 
         [0010]    For instance, the valve has an inflow space for feeding in process medium, a feed line being configured in the valve cone or in the valve body, which feed line connects the inflow space to the first pressure space in terms of flow. 
         [0011]    It is therefore proposed to configure an additional line, namely the feed line, in the valve cone or in the valve body, which additional line makes a communicating connection between the inflow space and the pressure space possible. 
         [0012]    Therefore, the pressure p 1  propagates in the first pressure space and finally leads to a force in the direction of the valve seat. 
         [0013]    A device is advantageously provided, for feeding steam into the second pressure space, the device being configured in such a way that, in the case of the movement of the valve cone in the direction of the valve seat, the second pressure space is loaded at the pressure p 0 , wherein: p 0 &lt;p 1 . 
         [0014]    The device is likewise advantageously configured in such a way that, in the case of the movement of the valve cone in the opposite direction to the valve seat, the second pressure space is loaded at the pressure p 1 . Therefore, the device can comprise at least one valve which produces a connection in flow terms to the process medium either at the pressure p 1  or p 0 . 
         [0015]    In a further advantageous development, the valve body has a third pressure space which is configured in such a way that, in the case of loading in the third pressure space at the pressure p 0 , a pressure force is exerted on the valve cone in the direction of the valve seat. The valve cone is advantageously of tubular configuration, the valve cone having a step on the end side, an upper step being assigned to the third pressure space and a lower step being assigned to the first pressure space. 
         [0016]    A further valve cone which is configured for regulation and for quick-action closure of a flow of steam is advantageously arranged within the valve cone. 
         [0017]    According to the invention, the valve cone is configured for quick-action closure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    The invention will now be explained in greater detail using one exemplary embodiment. In the drawing, diagrammatically: 
           [0019]      FIG. 1  shows a valve in the closed state, and 
           [0020]      FIG. 2  shows a valve in the open state. 
       
    
    
     DETAILED DESCRIPTION OF INVENTION 
       [0021]      FIG. 1  shows a valve  1  comprising a valve cone  2 , a valve seat  3  and a valve body  4 . A further optional actuator valve cone  5  is arranged within the valve body  4 . The valve cone  2  is configured so as to be substantially rotationally symmetrical about a rotational symmetry axis  6 . Here, the valve body  4  can be moved in the direction of the rotational axis symmetry axis  6  in the direction of the valve seat  3  and can also be configured such that it can be moved counter to the valve seat  3 . 
         [0022]    The valve body  4  and the valve seat  3  are configured as an integral component. An inflow space  7  is arranged in the valve  1 , into which inflow space  7  a process medium, for example steam, can flow. Furthermore, the valve  1  comprises an outflow space  8 . The steam is fed finally to a steam turbine  10  via a flow connection  9 . The valve  1  is configured for a turbomachine, in particular a steam turbine  10 . 
         [0023]    The valve body  4  has a first pressure space  11 . Here, the first pressure space  11  is configured in such a way that, in the case of loading in the first pressure space  11  at the pressure p 1  the valve cone  2  moves in the direction of the valve seat  3 . 
         [0024]    The valve body  4  has a second pressure space  12  which is configured in such a way that, in the case of loading in the second pressure space  12  at the pressure p 1  the valve cone  2  moves in the opposite direction away from the valve seat  3 . 
         [0025]    In the direction of the drawing of  FIG. 1 , the valve cone  2  would move upward in this case. 
         [0026]    A process medium, in particular steam at the pressure p 1  is situated as a rule in the inflow space  7 . 
         [0027]    The valve cone  2  or the valve body  4  has a feed line  13  or  20  which connects the inflow space  7  to the first pressure space  11  in terms of flow. To this end, a flow connection is situated in the valve cone  2 , which flow connection can be configured, for example, as an annular channel and extends rotationally symmetrically over the symmetry axis  6 . Here, the feed line  13  has an opening  14  which points on the outer side in the direction of the inflow space  7 . 
         [0028]    The valve  1  has a device (not shown in greater detail) for feeding steam at the pressure p 0  or p 1  into the second pressure space  12 , and a device (not shown in greater detail) for feeding steam at the pressure p 0  into a third pressure space  19 , the device being configured in such a way that, in the case of the movement of the valve cone  2  in the direction of the valve seat  3 , the second pressure space  12  is loaded at the pressure p 0 , wherein: p 0 &lt;p 1 . 
         [0029]    In the case of a movement in the opposite direction, that is to say away from the valve seat, the second pressure space  12  is loaded at the pressure p 1 . 
         [0030]    In order to make this movement of the valve cone  2  possible, the valve cone  2  is of tubular configuration with respect to the rotational symmetry axis  6 , the valve cone  2  having a step  16  on the end side  15 , an upper step  17  and a lower step  18  being arranged on the end side  15 . 
         [0031]    The valve body  4  has a third pressure space  19  which is configured in such a way that, in the case of loading in the third pressure space  19  at the pressure p 0 , a pressure force is exerted on the valve cone  2  in the direction of the valve seat  3 . 
         [0032]    The valve cone  2  has a projected effective first pressure area A 1  in the first pressure space  11 , as viewed in the direction of the valve seat  3  (that is to say, in the direction of the rotational symmetry axis  6 ). 
         [0033]    The valve cone  2  has a projected effective second pressure area A 2  in the second pressure space  12  in the direction away from the valve seat  3 . 
         [0034]    The valve cone  2  has a projected effective third pressure area A 3  in the third pressure space  19 , as viewed in the direction of the valve seat  3 . The valve cone  2  has a projected effective fourth pressure area A 4  in the inflow space  7  in the direction away from the valve seat  3 . Here: A 1 &lt;A 2 , A 1 &gt;A 4 , A 1 +A 3 &gt;A 2 , A 1 +A 3 =A 2 +A 4 . This means that, in the case of identical pressures p 1  in the first (A 1 ) and fourth (A 4 ) pressure space and a pressure p 0  in the second (A 2 ) and third (A 3 ) pressure space and p 1 &gt;p 0 , the pressure force overall on the area A 1 +A 3  is greater than on the area A 2 +A 4 , which leads to a movement of the valve cone  2  toward the valve seat  3  and therefore makes closure of the valve  1  possible. 
         [0035]    Furthermore, this means that, in the case of identical pressures p 1  in the first (A 1 ), second (A 2 ) and fourth (A 4 ) pressure space and a pressure p 0  in the third (A 3 ) pressure space and p 1 &gt;p 0 , the pressure force overall on the area A 2 +A 4  is greater than on the area A 1 +A 3 , which leads to a movement of the valve cone  2  away from the valve seat  3  and therefore makes opening of the valve  1  possible. 
         [0036]    As a result, the valve  1  can be opened and closed only by way of a change in the pressure between p 1  and p 0  in the pressure space  12  at constant pressures p 0  in the pressure space  19  and p 1  in the pressure space  11  and inflow space  7 . 
         [0037]    Furthermore, the valve  1  is automatically closed in the case of a pressure drop from p 1  to p 0  in the pressure space  12  and a pressure p 1  prevailing in the inflow space. 
         [0038]    The valve cone  2  is configured for quick-action closure. 
         [0039]    Therefore, the upper step  17  is assigned to the third pressure space  19  and the lower step  18  is assigned to the first pressure space  11 . 
         [0040]    In addition to the quick-action closure function, the actuator valve cone  5  also has a function for regulating the flow of steam. 
         [0041]    Therefore, according to the invention, it is made possible by way of various geometries of the working spaces and the use of two thermodynamic more differentiated steam states that the valve  1  remains in the closed position in the case of prevailing process media at the pressures p 0  and p 1  and is opened by way of the targeted feed of the process medium p 1  into the pressure space  12 .