Title of Invention

"STEAM TURBINE PLANT"

Abstract

A steam turbine plant (2) should having for control of the insertion of steam (D) in a seam collecting space (40, 44) a steam inlet valve (38, 42) with a specially high control-quality, at which losses of steam (D) are held specially low. For this purpose the steam inlet valve (38, 42) has, in accordance with the Invention, a rotary shaft (64) attached in a housing (52) as shut-off device, where a steam inlet (54) is jointable through a channel (80) provided in the surface (66) of the rotary shaft (64) with a steam outlet (56).

Full Text

-1A- The invention relates to a steam-turbine plant, wherein a steam-collecting space is arranged upstream of its steam turbine and a steam-inlet vaive is provided for controlling the introduction of steam into the steam-collecting space. A steam-turbine plants is generally used for generating electrical energy or even for driving a machine. A working medium, normally a water-water/steam mixture, which is directed in an evaporator circuit of the steam-turbine plant, is evaporated in an evaporator. The steam generated in the process expands to perform work in the steam turbine and is then fed to a condenser or a machine. The working medium condensed in the condenser is then fed back to the evaporator via a feedwater pump. In steam-turbine plants, control valves designated as nozzle-group control serve to control the introduction of steam into a steam-collecting space. The control valves are normally opened and closed by a spindle system or by a hydraulic drive. In the case of a spindle system, the control valves are hung in a beam which is arranged in the steam-collecting space and can be moved by two spindles. Alternatively, the control valves may have hydraulic individual units. The hydraulic individual units normally actuate the individual control valves via a linkage. -2- Such control valves require especially high actuating forces, since they have to be closed counter to the direction of the steam flow. High actuating forces in turn slow down the actuating speed of the control valves and thus have an adverse effect on the control performance of the control valves. In addition, the spindles of the spindle system or of the linkage of the hydraulic system are normally passed in each case through a stuffing box through the casing of the steam-collecting space. Since the respective nozzle-group control is actuated through the corresponding stuffing boxes, losses of steam cannot be avoided in the process. Such losses may turn out to be especially high where there are a plurality of stuffing boxes. Therefore, to overcome the problems, the present invention provides a steam turbine plant of the above mentioned nature with a steam inlet valve, which permits an especially high control performance and in which steam losses turn out to be especially low. a steam-inlet valve disposed to control a flow of steam into the steam-collecting space at the inlet side; This problem is solved in accordance with the present invention in which the steam-inlet valve has a housing formed with a steam inlet and a steam outlet, and a rotary cylinder disposed in the housing and forming a shut-off member, the rotary cylinder being formed with a passage enabling a connection between the steam inlet and the steam outlet. The invention is based on the idea that an especially high control performance can be achieved for a steam-inlet valve of a steam-turbine plant by this steam-inlet valve being designed for especially low actuating forces. Especially low actuating forces are possible if the steam-inlet valve is designed in such a way -3- that actuating movements in a direction along the direction of the steam flow are largely avoided. This can be achieved in an especially simple manner by the steam-inlet valve being designed not for linear actuating movements but for rotational actuating movements. To this end, a rotary cylinder is provided as a shut-off member of the steam-inlet valve. In such an arrangement, the number of requisite seals is also especially small. The steam-inlet valve therefore has especially low losses of steam. In accordance with an added feature of the invention, the rotary cylinder has a peripheral surface and the passage of the steam-inlet valve extends along the peripheral surface of the rotary cylinder, i.e., the passage is run on the surface of the rotary cylinder. This is because a steam-inlet valve of such a design can be adapted to various requirements in an especially flexible manner. For example, the steam inlet can be connected to the steam outlet even in different positions of the rotary cylinder if a suitable length of the passage is selected. In order to additionally keep the risk of steam loss especially low, the housing enclosing the rotary cylinder is advantageously made in one piece. The rotary cylinder is thereby inserted into the housing via a single access opening, which is sealed off from the surroundings via an end plate arranged on-the free of the rotary cylinder. The end plate of the steam-inlet valve is advantageously designed in such a way that it has a crenellated profile, in cross section, on its side facing the housing of the rotary cylinder. Steam escaping at the sealing point must then cover an especially long distance to reach the surroundings, as a result of which the risk of undesirable steam escape is kept especially low. Advantageously the end of the rotary cylinder is arranged inside the housing mounted in a conical bearing element arranged in the housing of the rotary cylinder. This is because such a configuration permits especially simple assembly, since the conical bearing element results in automatic centering when the rotary cylinder is inserted. The steam-inlet valve advantageously has a spring system which mechanically preloads the rotary cylinder. In this design, the steam-inlet valve is suitable for especially short quick-closing times and closes automatically in the event of a failure of the system controlling the rotary movement of the rotary cylinder. Steam losses caused by an accident can thus be avoided. The steam to be introduced into the steam-collecting space may contain an especially high proportion of impurities, depending on the operating mode and the operating conditions. So that the steam-inlet valve is insensitive to such impurities, it advantageously has a rotary cylinder whose surface is made of a ceramic material. This is because a ceramic material has especially low adhesion for impurities in the steam and is also especially insensitive to excessive changes in temperature. In order to also ensure operating capability even in the case of especially low steam quality, a permanent high-frequency disturbance signal may be applied as actuating signal to the steam-inlet valve, and this disturbance signal ensures ease of motion of the valve. -5- Advantageously the passage run in the surface of the rotary cylinder has a narrowing cross section. This is because different flow rates of the steam can then be set when the passage is appropriately positioned relative to the steam inlet and/or the steam outlet. In accordance with another feature of the invention, the passage advantageously has an arc angle which is defined by a starting point and by an end point of the passage relative to the rotary-cylinder axis and is greater than 180 degree. In other words, the passage extends over more than half the circumference of the rotary cylinder. This is because in this design an especially large number of combinations of a passage cross section section with a steam inlet and/or steam outlet are possible. For special flexibility when setting the flow rate of the steam, the steam-inlet valve advantageously has a plurality of passages which are arranged on the surface of a common rotary cylinder. In this arrangement, a steam inlet can be connected in each case via a passage to a steam outlet assigned to it. In such an arrangement, given a suitable design of the rotary cylinder, it is possible to open one or more passages in a specific manner depending on the operating position of the rotary cylinder. Advantageously the arc angles of the passages are formed in such a way that steam can flow through a first passage in a first position of the rotary cylinder and steam can flow through the first passage and a second passage in a second position of the rotary cylinder. In this design, the steam-inlet valve permits gradual opening of the passages, as a result of which especially high flexibility during the feeding of steam into the steam-collecting space is possible. -6- The steam-inlet valve is advantageously connected to a steam-collecting space which is arranged upstream of a steam turbine of a steam-turbine plant. This is because the steam-inlet valve is especially suitable for this purpose on account of its especially high control performance and on account of the fact that there is an especially low risk of steam loss from this steam-inlet valve. The advantages achieved with the invention consist in particular in the fact that, in the steam turbine plant having the steam-inlet valve arranged upstream of a steam-collecting space, the risk of steam losses is kept especially low on account of the rotary cylinder provided as a shut-off member. In addition, the steam-inlet valve has especially low actuating forces, since it is designed for rotational actuating movements. As a result, the steam-inlet valve has an especially high actuating speed and thus an especially high control performance. In addition, the especially low actuating forces permit the use of an electrical control mechanism for the steam-inlet valve. It is therefore possible to dispense with a hydraulic actuating system, which on account of the hydraulic oils is always a potential source of fire in the steam-turbine plant. Exemplary embodiments of the present invention can be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. FIG. 1 is a schematic diagram of a steam-turbine plant with two steam-inlet valves for controlling the introduction of steam into the steam turbine; FIG. 2 is a schematic view of the configuration of a steam-inlet valve on the steam turbine according to FIG. 1; _7- FIG. 3 is a perspective diagrammatic view of a steam-inlet valve according to FIGS. 1 and 2; FIG. 4 is a partial section of the configuration of the end plate on the housing of one of the steam-inlet valves according to FIGS. 1 to 3; and FIG. 5 is a schematic view illustrating the arc angles of the passages arranged on the surface of the rotary cylinder according to FIG. 3. Identical and functionally equivalent parts are identified with the same reference numerals throughout the figures. Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is seen a steam-turbine plant 2 according to FIG. 1 comprises that has a steam turbine 4 with coupled generator 6 and, in a water/steam loop 8, a condenser 10 arranged downstream of the steam turbine 4. The plant further includes a steam generator 12. The steam turbine 4 has a first pressure stage or a high-pressure part 4a and a further stage or an intermediate-and low-pressure part 4b, which drive the generator 6 via a common shaft 14. The steam generator 12 is connected on the steam-outlet side to the steam inlet 18 of the high-pressure part 4a of the steam turbine 4. A steam outlet 20 of the high-pressure part 4a of the steam turbine 4 is connected via an overflow line 22 to a steam inlet 24 of the intermediate- and low-pressure part 4b of the steam turbine 4. A steam outlet 26 of the intermediate- and low-pressure part 4b of the steam turbine 4 is connected via steam line 28 to the condenser 10. The latter, via a feedwater line 30, in which a feedwater pump 32 and a feedwater tank 34 are connected, is connected to the steam generator 12 in such a way that a closed water/steam loop 8 is obtained. -8- The steam-turbine plant 2 is configured so that the introduction of steam D into the high-pressure part 4a and the intermediate and low-pressure part 4b of the steam turbine 4 is controlled. To this end, the steam line 36 connecting the steam generator 12 and the steam turbine 4 opens into a steam-inlet valve 38 disposed on the inlet side upstream of the steam-collecting space 40. The latter is a casing of the turbine of the high-pressure part 4a of the steam turbine 4. In addition, a steam-inlet valve 42 is connected in the overflow line 22 and is arranged on the inlet side upstream of the steam-collecting space 44 designed as a casing of the turbine of the intermediate- and low-pressure part 4b of the steam turbine 4. The steam-inlet valves 38, 42 are more or less of identical construction and can be controlled by means of an electrical actuating signal to which a high-frequency disturbance signal is applied. For this purpose, the steam-inlet valves 38, 42 are each connected via control lines 46 and 48 respectively to a control unit 50. As shown in FIG. 2, the steam-inlet valve 38 is fastened directly to the steam-collecting space 40. Steam D passes from the steam line 36 into the steam-collecting space 40 via the steam-inlet valve 38. In its housing 52, the steam-inlet valve 38 has three steam inlets 54 and three steam outlets 56. The steam outlets 56 of the steam-inlet valve 38 open in each case into a chamber 40a, 4b, or 40c, respectively, of the steam collecting space 40. In the steam-collecting space 40 of the high-pressure stage 4a of the steam turbine 4 a turbine 58 is arranged which comprises a rotor 60 and a number of turbine blades 62. The steam-inlet valve 42 is arranged in roughly the same manner on the steam-collecting space 44 configured as the casing of the turbine of the turbine, of the intermediate-and low-pressure part 4b of the steam turbine 4. -9- Referring now to FIG. 3, there is shown, as an example of the steam-inlet valves 38, 42 of more or less identical construction, the steam-inlet valve 38 according i! to FIGS, 1 and 2 is shown in FIG.3. The steam-inlet valve 38 comprises a housing 52. Three steam inlets 54 and three steam outlets 56 are arranged in the housing 52, The housing 52 is made in one piece, A rotary cylinder 64 is disposed in the housing 52. A surface 66'jof the cylinder 64 has a crenellated profile. It is made of a ceramic material K. The rotary cylinder 64 can be placed into the housing 52 via an access opening 68. With its end 64a arranged inside the housing 52, the rotary cylinder 64 is mounted in a conical bearing element 70 inside the housing 52. An end plate 72 is arranged on that end 64b of the rotary cylinder 64 which is not mounted in the housing 52, With reference to the detail in FIG. 4, the end plate 72 has a crenellated profile 74 on the side 72a facing the housing 52. A guide 76 is arranged on the end plate 72 of the rotary cylinder 64. The rotary cylinder 64 can be reset mechanically by a spring system 78, through the guide 76. The rotary cylinder 64 has in its surface 66 three passages 80, 82 and 84, via which the steam inlets 54 can be connected to the steam outlets 56 assigned to them in each case. In this arrangement, the cross section of the passages 80, 82 and 84, in each case narrows along the steam path in a manner not shown in any more detail. In addition, the passages 80, 82, 84, as shown in detail in FIG. 5, each have different arc angles 86, 88 and 90 respectively, which are each defined via a starting point 86a, 88a, 90a and an end point 86b, 88b, 90b. The arc angles 86, 88, 90 are selected in such a way that they are each greater than 180 degree. In this case, steam D can flow through the passage 80 in a first position of the rotary cylinder 64, steam D can flow through the passage 80 and -10- the passage 82 in a second position of the rotary cylinder 64, and steam D can flow through the passage 80, the passage 82 and the passage 84 in a third position of the rotary cylinder 64. An especially finely graduated control of the introduction of steam D into the respective steam-collecting spaces 40 and 44 of the steam-turbine plant is ensured by the especially high control performance of the steam-inlet valves 38, 42. At the same time, on account of the fact that the rotary cylinder 64 is configured as a shut-off member, the risk of the loss of steam D is kept especially low. -11- We Claim 1. A steam-turbine plant (2) comprising: a steam turbine (4); a steam-collecting space (40, 44) with an inlet side upstream of said steam turbine (4); a steam-inlet valve (38, 42) disposed to control a flow of steam (D) into said steam-collecting space (40, 44) at said inlet side; wherein said steam-inlet valve (38, 42) having a housing (52) formed with a steam inlet (54) and a steam outlet (56) and a rotary cylinder (64) disposed in said housing (52) and forming a shut-off member, said rotary cylinder (64) being formed with a passage (80) enabling a connection between said steam inlet (54) and said steam outlet (56). 2. The steam-turbine plant according to claim 1, wherein said rotary cylinder (64) has a peripheral surface (66) and said passage (80) of said steam- inlet valve (38, 42) extends along said peripheral surface (66) of said rotary cylinder (64). 3. The steam-turbine plant according to claim 1, wherein said housing (52) of said steam-inlet valve (38, 42) is a one-piece housing formed with a single access opening (68) into which said rotary cylinder (64) is inserted into said housing (52), and wherein an end plate (42) disposed on a free end (646) of said rotary cylinder (64) seals off an interior space of said housing towards outside. -12- 4. The steam-turbine plant (2) according to claim 3, wherein said end plate (72) is formed with a crenellated profile (74) on a side (72a) thereof facing said housing. 5. The steam-turbine plant (2) according to claim 3, which comprises a conical bearing element (70) disposed inside said housing (52) for mounting an end of said rotary cylinder inside said housing. 6. The steam-turbine plant (2) according to claim 1, which comprises a spring (78) mechanically preloading said rotary cylinder (64) of said steam-inlet valve (38,42). 7. The steam-turbine plant (2) according to claim 1, wherein a surface (66) of said rotary cylinder (64) of said steam-inlet valve (38, 42) is made of a ceramic material (K). 8. The steam-turbine plant (2) according to claim 1, wherein said steam-inlet valve (38, 42) is configured to be controlled with an actuating signal carrying a permanent disturbance signal. 9. The steam-turbine plant (2) according to claim 2, wherein said passage (80) has a narrowing cross-section on rotation in a given direction. -13- 10.The steam-turbine plant (2) according to claim 1, wherein said passage (80) is one of a plurality of passages (80, 82, 84) formed on a surface of said rotary cylinder (64), and a respective said steam inlet (54) is connectable with a respective said steam outlet (56) via one of said passages (80, 82, 84). 11.The steam-turbine plant (2) according to claim 10, wherein said passages (80, 82, 84) extend along a respective arc angle, (86, 88, 90) defined between a starting point (86a, 88a, 90a) and an end point (86b, 88b, 90b) of said passage greater than 180 degree. 12.The steam-turbine plant (2) according to claim 11, wherein said arc angles (86, 88, 90) of said passages (80,82, 84) of the steam-inlet valve (38, 42) are selected such that steam (D) can flow substantially exclusively through a first one of said passages in a first position of said rotary cylinder (64) and steam can flow through said first passage (80) and a second one of said passages (82) in a second position of said rotary cylinder (64). A steam turbine plant (2) should having for control of the insertion of steam (D) in a seam collecting space (40, 44) a steam inlet valve (38, 42) with a specially high control-quality, at which losses of steam (D) are held specially low. For this purpose the steam inlet valve (38, 42) has, in accordance with the Invention, a rotary shaft (64) attached in a housing (52) as shut-off device, where a steam inlet (54) is jointable through a channel (80) provided in the surface (66) of the rotary shaft (64) with a steam outlet (56).

Documents:

00196-cal-1999-abstract.pdf

00196-cal-1999-claims.pdf

00196-cal-1999-correspondence.pdf

00196-cal-1999-description(complete).pdf

00196-cal-1999-drawings.pdf

00196-cal-1999-form-1.pdf

00196-cal-1999-form-18.pdf

00196-cal-1999-form-2.pdf

00196-cal-1999-form-3.pdf

00196-cal-1999-form-5.pdf

00196-cal-1999-g.p.a.pdf

00196-cal-1999-letters patent.pdf

00196-cal-1999-priority document others.pdf

00196-cal-1999-priority document.pdf