Abstract:
A steam valve is provided including a chest, a lock, a spindle, and a strainer. Each of these components is made of specific Ni alloys combinations that enable the valve to operate at temperatures above 650° C. with a good service life.

Description:
RELATED APPLICATION 
       [0001]    The present application hereby claims priority under 35 U.S.C. Section 119 to Italian Patent application number MI2011A000830, filed May 12, 2011, the entire contents of which are hereby incorporated by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present disclosure relates to high temperature-resistant steam valves, and more particularly to steam valves for steam turbines. For the purposes of this specification the term “high-temperature” shall be taken to mean at least 650 degrees Celsius. 
       BACKGROUND 
       [0003]    An effective means to increase power generation efficiency of a steam turbine is to raise the turbine steam temperature to 650 deg. C. or more. 
         [0004]    Special considerations may be made for these high temperatures. For example, the valve may require cooling features or additionally may be made of high hot strength materials. While cooling means typically have only limited effectiveness, the use of different materials in a valve can introduce problems as different materials have different coefficients of expansion and thus upon heating, unacceptable internal stresses may be created which may adversely affect service life. 
       SUMMARY 
       [0005]    The present disclosure relates to a steam valve including a chest, a lock, a spindle, and a strainer. Each of these components is made of specific Ni alloys combinations that enable the valve to operate at temperatures above 650° C. with a good service life. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0006]    By way of example, an embodiment of the present disclosure is described more fully hereinafter with reference to the accompanying drawing, in which: 
           [0007]      FIG. 1  is a cut view of a pair of steam valves to which embodiments may be applied 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Introduction to the Embodiments 
       [0008]    A high temperature steam valve is disclosed that addresses the problem of service life, particularly the problem of cracking and oxidation due to high temperature operation. 
         [0009]    The disclosure attempts to address this problem by means of the subject matters of the independent claim. Advantageous embodiments are given in the dependent claim. 
         [0010]    The disclosure is based on the general idea using specific materials combinations for component pieces of a steam turbine valve. 
       DETAILED DESCRIPTION 
       [0011]    An exemplary embodiment of the present disclosure is now described with reference to the drawing, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth to provide a thorough understanding of the disclosure. However, the present disclosure may be practiced without these specific details, and as such is not limited to the exemplary embodiments disclosed herein. 
         [0012]      FIG. 1  shows a series of two high temperature steam turbine valves  5 . Exemplary embodiments maybe applied to any one or both of the valves  5 . The valves  5  each comprise a chest  10 , which is a casing that forms a chamber. In the chamber is a lock  17  with a cavity through which a spindle  15  extends. The spindle  15  has two distal ends. One end protrudes out from the chest  10  while the other end is located in the chamber. The purpose of the lock  17  is to guide the movement of the spindle  15  whose purpose is to movably position a valve closing member  20 , for example a disk, plug or equivalent, relative to a seat  24 , so as to bring the valve  5  either into an open or closed state. A strainer  25  is located in the chamber upstream of the closing means and preferably at least partially in the inlet port  12 . These locations enable the strainer  25  to perform its function of retaining solid particles typically present in the steam, thus reducing potential damage to the valves closing means. 
         [0013]    At a downstream end of the valve  5 , a plurality of bolts  30  are optionally provided. The purpose of the bolts  30  is to provide a means to fix the valve  5  relative to further steam turbine equipment items. These items may include, but are not limited to further piping, turbine casings, and further valves. 
         [0014]    In an exemplary embodiment, the chest  10  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent: C, from 0.01 to 0.03; Cr, from 20.0 to 23.0; Mo, from 8.0 to 10.0; Nb, from 3.20 to 3.80; Ti, from 0.1 to 0.30; Al, from 0.10 to 0.30; Mn, from 0.10 to 0.50; and Si, from 0.05 to 0.30; a plurality of residual elements comprising, in weight percent, up to: 4.0 Fe; 1.0 Co; 0.015 P; and 0.015 S; and a balance of Ni. 
         [0015]    In an exemplary embodiment, the chest  10  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent. C, from 0.04 to 0.08; Cr, from 18.5 to 20.5; Mo, from 8.0 to 9.0; Co, from 9.0 to 11.0; Ti, from 1.9 to 2.3; and B, 0.003 to 0.005; a plurality of residual elements comprising, in weight percent: up to, 0.3 Mn; 1.5 Fe, and 0.15 Si; and a balance of Ni. 
         [0016]    In an exemplary embodiment, the chest  10  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.02 to 0.06, Cr from 23.0 to 26.0, Co from 19.0 to 21.0, Ti from 1.1 to 1.9, Al from 0.9 to 1.5, and Nb from 1.0 to 1.6; a plurality of residual elements comprising, in weight percent, up to 1.5 Fe, 0.6 Mo, 0.5 Si, 0.4 Mn; and a balance of Ni. 
         [0017]    In an exemplary embodiment, the chest  10  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.01 to 0.03, Cr from 20.0 to 23.0, Mo from 8.0 to 10.0, and Nb from 3.15 to 4.15; a plurality of residual elements comprising, in weight percent, up to, 5.0 Fe, Ti 0.40 Ti, 0.40 Al, 0.1 Mn, 0.10 Si, 0.010 P, 0.005 S, 0.1 Cu, and 0.1 Co; and a balance of Ni. 
         [0018]    In an exemplary embodiment, the chest  10  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.05 to 0.1, Cr from 20.0 to 23.0, Mo from 8.5 to 10.0. Co from 11.0 to 14.0. Ti from 0.2 to 0.6, and Al from 0.7 to 1.4; a plurality of residual elements comprising, in weight percent, up to, 2.0 Fe, 0.2 Mn, 0.2 Si, 0.010 P, 0.010 S, 0.5 Cu, and 0.006 B; and a balance of Ni. 
         [0019]    In an exemplary embodiment, the chest  10  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.05 to 0.1, Cr from 21.5 to 23.0, Mo from 8.5 to 10.0, Co from 11.5 to 13.0 Ti from 0.4 to 0.6, Al from 1.0 to 1.30, and B from 0.003 to 0.006; a plurality of residual elements comprising, in weight percent, up to, 2.0 Fe, 0.1 Mn, 0.1 Si, 0.010 P, 0.050 S, 0.5 Cu; and a balance of Ni. 
         [0020]    In an exemplary embodiment, the spindle  15  shown in  FIG. 1  is made of a heat resisting, material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.03 to 0.07, Cr from 23.8 to 24.8, Mo from 1.2 to 1.7 Co from 19.0 to 20.5, Ti from 2.8 to 3.2, Al from 1.2 to 1.6, Nb from 0.7 to 1.2, Zr from 0.03 to 0.07, B from 0.01 to 0.015; a plurality of residual elements comprising, in weight percent, up to, 1.0 Fe, 0.5 Mn, 0.5 Si, 0.0050 P, 0.0050 S, 0.2 Cu, 0.006 Mg, 0.05 Ta; and a balance of Ni. 
         [0021]    In an exemplary embodiment, the spindle  15  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.04 to 0.08, Cr from 18.5 to 20.5, Mo from 8.0 to 9.0, Co from 9.0 to 11.0, Ti from 1.9 to 2.3, and B 0.003 to 0.005; a plurality of residual elements comprising, in weight percent, up to, 0.3 Mn, 1.5 Fe, and 0.15 Si; and a balance of Ni. 
         [0022]    In an exemplary, embodiment, the spindle  15  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.02 to 0.06, Cr from 23.0 to 26.0, Co from 19.0 to 21.0, Ti from 1.1 to 1.9, Al from 0.9 to 1.5, and Nb from 1.0 to 1.6; a plurality of residual elements comprising, in weight percent, up to, 1.5 Fe, 0.6 Mo, 0.5 Si, 0.4 Mn; and a balance of Ni. 
         [0023]    In an exemplary embodiment, the spindle  15  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, Cr from 14.0 to 15.7, Mo from 4.5 to 5.5, Co from 18.0 to 22.0, Al from 4.5 to 4.9, Ti from 0.9 to 1.5, and B from 0.003 to 0.010; a plurality of residual elements comprising, in weight percent, up to 0.12 C, 1.0 Fe, 1.0 Mn, 1.0 Si, 0.0050 S, 0.2 Cu, and 0.15 Zr; and a balance of Ni. 
         [0024]    In an exemplary embodiment, the spindle  15  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent C from 0.04 to 0.08, Cr from 19.0 to 21.0, Mo from 5.6 to 6.1 Co from 19.0 to 21.0 Ti from 1.9 to 2.4, and a combination of Ti and Al from 2.4 to 2.8; a plurality of residual elements comprising, in weight percent, up to, 0.7 Fe, 0.6 Mn, 0.40 Si, 0.60 Al, 0.007 S, 0.0020 Pb, 0.20 Cu, 0.0001 Bi, 0.005 B and a balance of Ni, 
         [0025]    In an exemplary embodiment, the lock  17  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.01 to 0.03, Cr from 20.0 to 23.0, Mo from 8.0 to 10.0, Nb from 3.20 to 3.80, Ti from 0.1 to 0.30, Al from 0.10 to 0.30, Mn from 0.10 to 0.50, and Si from 0.05 to 0.30; a plurality of residual elements comprising, in weight percent, up to, 4.0 Fe, 1.0 Co, 0.015 P, and 0.015 S; and a balance of Ni. 
         [0026]    In an exemplary embodiment, the lock  17  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.04 to 0.08, Cr from 18.5 to 20.5, Mo from 8.0 to 9.0, Co from 9.0 to 11.0, Ti from 1.9 to 2.3, and B 0.003 to 0.005; a plurality of residual elements comprising, in weight percent, up to, 0.3 Mn, 1.5 Fe, and 0.15 Si; and a balance of Ni. 
         [0027]    In an exemplary embodiment, the lock  17  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.02 to 0.06, Cr from 23.0 to 26.0, Co from 19.0 to 21.0, Ti from 1.1 to 1.9, Al from 0.9 to 1.5, and Nb from 1.0 to 1.6; a plurality of residual elements comprising, in weight percent, up to, 1.5 Fe, 0.6 Mo, 0.5 Si, 0.4 Mn; and a balance of Ni. 
         [0028]    In an exemplary embodiment, the lock  17  shown in of  FIG. 1  is made of a heat resisting, material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.01 to 0.03, Cr from 20.0 to 23.0 Mo from 8.0 to 10.0, and Nb from 3.15 to 4.15; a plurality of residual elements comprising, in weight percent, up to, 5.0 Fe, Ti 0.40 Ti, 0.40 Al, 0.1 Mn, 0.10 Si, 0.010 P, 0.005 S, 0.1 Cu, and 0.1 Co; and a balance of Ni. 
         [0029]    In an exemplary embodiment, the lock  17  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.05 to 0.1, Cr from 20.0 to 23.0, Mo from 8.5 to 10.0, Co from 11.0 to 14.0, Ti from 0.2 to 0.6, and Al from 0.7 to 1.4; a plurality of residual elements comprising, in weight percent, up to, 2.0 Fe, 0.2 Mn, 0.2 Si, 0.010 P, 0.010 S, 0.5 Cu, and 0.006 B; and a balance of Ni. 
         [0030]    In an exemplary embodiment, the lock  17  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.05 to 0.1, Cr from 21.5 to 23.0, Mo from 8.5 to 10.0, Co from 11.5 to 13.0, Ti from 0.4 to 0.6, Al from 1.0 to 1.30, and B from 0.003 to 0.006; a plurality of residual elements comprising, in weight percent, up to, 2.0 Fe, 0.1 Mn, 0.1 Si, 0.010 P, 0.050 S, 0.5 Cu; and a balance of Ni. 
         [0031]    In an exemplary embodiment, the lock  17  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.04 to 0.08, Cr from 19.0 to 21.0, Mo from 5.6 to 6.1, Co from 19.0 to 21.0, Ti from 1.9 to 2.4, and a combination of Ti and Al from 2.4 to 2.8; a plurality of residual elements comprising, in weight percent, up to, 0.7 Fe, 0.6 Mn, 0.40 Si, 0.60 Al, 0.007 S, 0.0020 Pb, 0.20 Cu, 0.0001 Bi, 0.005 B and a balance of Ni. 
         [0032]    In an exemplary embodiment, the strainer  25  of  FIG. 1  is made of a heat resisting material consisting of a plurality of main alloying elements comprising, in weight percent, C from 0.01 to 0.03, Cr from 20.0 to 23.0 Mo from 8.0 to 10.0 Nb from 3.20 to 3.80, Ti from 0.1 to 0.30, Al from 0.10 to 0.30, Mn from 0.10 to 0.50, and Si from 0.05 to 0.30; a plurality of residual elements comprising, in weight percent, up to, 4.0 Fe, 10.0 Co, 0.015 P, and 0.015 S; and a balance of Ni. 
         [0033]    In an exemplary embodiment, the strainer  25  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.04 to 0.08, Cr from 18.5 to 20.5, Mo from 8.0 to 9.0, Co from 9.0 to 11.0, Ti from 1.9 to 2.3, and B 0.003 to 0.005; a plurality of residual elements comprising, in weight percent, up to, 0.3 Mn, 1.5 Fe, and 0.15 Si; and a balance of Ni. 
         [0034]    In an exemplary embodiment, the strainer  25  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.02 to 0.06, Cr from 23.0 to 26.0, Co from 19.0 to 21.0, Ti from 1.1 to 1.9, Al from 0.9 to 1.5, and Nb from 1.0 to 1.6; a plurality of residual elements comprising, in weight percent, up to 1.5 Fe, 0.6 Mo, 0.5 Si, 0.4 Mn; and a balance of Ni. 
         [0035]    In an exemplary embodiment, the strainer  25  of  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.01 to 0.03, Cr from 20.0 to 23.0, Mo from 8.0 to 10.0, and Nb from 3.15 to 4.15; a plurality of residual elements comprising, in weight percent, up to 5.0 Fe, 0.40 Ti, 0.40 Al, 0.1 Mn, 0.10 Si, 0.010 P 0005 S, 0.1 Cu, and 0.1 Co; and a balance of Ni. 
         [0036]    In an exemplary embodiment, the strainer  25  of  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.05 to 0.1, Cr from 200 to 23.0, Mo from 8.5 to 10.0, Co from 11.0 to 14.0, Ti from 0.2 to 0.6, and Al from 0.7 to 1.4; a plurality of residual elements comprising, in weight percent, up to, 2.0 Fe, 0.2 Mn, 0.2 Si, 0.010 P, 0.010 S, 0.5 Cu, and 0.006 B; and a balance of Ni. 
         [0037]    In an exemplary embodiment, the strainer  25  of  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent 0.05 to 0.1 C, 21.5 to 23.0 Cr, 8.5 to 10.0 Mo, 11.5 to 13.0 Co, 0.4 to 0.6 Ti, 1.0 to 1.30 Al, and 0.003 to 0.006 B; a plurality of residual elements comprising, in weight percent, up to 2.0 Fe, 0.1 Mn, 0.1 Si, 0.010 P, 0.050 S, 0.5 Cu; and a balance of Ni. 
         [0038]    In an exemplary embodiment, the bolts  30  of  FIG. 1  are made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.03 to 0.07, Cr from 23.8 to 24.8, Mo from 1.2 to 1.7, Co from 19.0 to 20.5, Ti from 2.8 to 3.2, Al from 1.2 to 1.6, Nb from 0.7 to 1.2, Zr from 0.03 to 0.07, B from 0.01 to 0.015; a plurality of residual elements comprising, in weight percent, up to, 1.0 Fe, 0.5 Mn, 0.5 Si, 0.0050 P, 0.0050 S, 0.2 Cu, 0.006 Mg, 0.05 Ta; and a balance of Ni. 
         [0039]    In an exemplary embodiment, the bolts  30  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.04 to 0.08, Cr from 18.5 to 20.5, Mo from 8.0 to 9.0, Co from 9.0 to 11.0, Ti from 1.9 to 2.3, and B 0.003 to 0.005; a plurality of residual elements comprising, in weight percent, up to, 0.3 Mn, 1.5 Fe, and 0.15 Si; and a balance of Ni. 
         [0040]    In an exemplary embodiment, the bolts  30  shown in  FIG. 1  is made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent, C from 0.02 to 0.06, Cr from 23.0 to 26.0, Co from 19.0 to 21.0 Ti from 1.1 to 1.9, Al from 0.9 to 1.5, and Nb from 1.0 to 1.6; a plurality of residual elements comprising, in weight percent, up to, 1.5 Fe, 0.6 Mo, 0.5 Si, 0.4 Mn; and a balance of Ni. 
         [0041]    In an exemplary embodiment, the bolts  30  of  FIG. 1  are made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent Cr from 14.0 to 15.7, Mo from 4.5 to 5.5, Co from 18.0 to 22.0, Al from 4.5 to 4.9, Ti from 0.9 to 1.5, and B from 0.003 to 0.010; a plurality of residual elements comprising, in weight percent, up to 0.12 C, 1.0 Fe, 1.0 Mn, 1.0 Si, 0.0050 S, 0.2 Cu, and 0.15 Zr; and a balance of Ni. 
         [0042]    In an exemplary embodiment, the bolts  30  of  FIG. 1  are made of a heat resisting material consisting of: a plurality of main alloying elements comprising, in weight percent Co from 12.0 to 15.0, Cr from 8.0 to 21.0, Mo from 3.50 to 5.00, Al from 1.2 to 1.6, Ti from 2.8 to 3.3, B from 0.0030 to 0.0100, Zr from 0.02 to 0.08, C from 0.02 to 0.1, and Mn from 0.02 to 0.1; a plurality of residual elements comprising, in weight percent, up to 0.15 Si, 0.015 P, 0.015 S, 2.0 Fe, and 0.10 Cu; and a balance of Ni. 
         [0043]    Although the disclosure has been herein shown and described in what is conceived to be the most practical exemplary embodiment, it will be that the present disclosure can be embodied in other specific. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The scope of the disclosure is indicated by the appended claims rather that the foregoing description and all changes that come within the meaning and range and equivalences thereof are intended to be embraced therein. 
       LIST OF REFERENCE NUMERALS 
       [0000]    
       
           5  Valve 
           10  Chest 
           12  Inlet port 
           15  Spindle 
           17  Lock 
           20  Valve closing member 
           24  Seat 
           25  Strainer 
           30  Bolt