JP4889518B2 - Valve rod removal device and valve rod removal method for steam turbine regulating valve - Google Patents

Description

  The present invention relates to a steam turbine adjusting valve that adjusts the flow rate of steam flowing into a turbine in a thermal power plant or the like, and more particularly to an apparatus and method for removing a valve rod inserted in a housing of a steam turbine adjusting valve.

The steam turbine control valve is installed at the inlet of a high-pressure turbine in a thermal power plant or the like, and controls the output of the turbine by adjusting the flow rate of steam flowing from the boiler into the turbine. The steam turbine control valve is an important part that controls the output of the turbine, and is periodically disassembled for functional inspection. In the steam turbine control valve, a valve rod is movably inserted in a housing (stand), and the flow rate of the steam is adjusted by moving the valve rod in the axial direction. During the periodic inspection of the steam turbine control valve, the valve stem is removed from the housing, and each part is checked. Removal of the valve stem from the housing is performed by fixing the housing to a large fixing device (for example, a vise) and hitting the end of the valve stem with a hammer or the like. For example, Patent Document 1 is known as a technique related to a steam turbine control valve. In the power plant of Patent Document 1, the efficiency of the power plant is increased by appropriately controlling the opening of the steam turbine control valve.
JP 2000-248908 A

  However, since the housing of the steam turbine control valve is large, it is difficult to fix with a vise and the workability is poor. Further, since the end of the valve stem is hit with a hammer several times by human power, excessive labor is required, and the valve stem may be damaged due to scratches or deformation. Furthermore, if the valve stem does not move even with the force of a hammer or the like, it has been necessary to cut the valve stem by machining to make it thinner and to remove the valve stem from the housing.

  SUMMARY OF THE INVENTION Therefore, the present invention provides a valve stem removing device and a valve stem for a steam turbine regulating valve that can remove the valve stem from the housing without damaging the housing without fixing the housing with a large fixture, and without requiring excessive labor. The purpose is to provide a removal method.

In order to achieve the above object, the invention according to claim 1 is capable of being screwed into a plurality of internal threads formed in the housing of the steam turbine adjusting valve into which the valve stem is inserted, and is formed on the outer peripheral surface over the entire length in the axial direction. A plurality of rods having male screws of the same diameter and a plurality of holes that are arranged to face the end surface of the valve stem and into which the plurality of rods arranged to surround the valve stem can be respectively inserted. A support plate that supports the housing in a horizontal state via the plurality of rods screwed to the housing; and a fixing position of the support plate in the axial direction of the rods that is screwed to the rods And a hydraulic cylinder that is supported by the support plate and is capable of pressing the end face of the valve stem, and that has a diameter of a cylinder rod that can contact the valve stem is smaller than the diameter of the valve stem. Hydraulic jack When a valve stem removal device of the steam turbine control valve, characterized in that it comprises a.

According to a second aspect of the present invention, a plurality of rods having external threads with the same diameter formed on the outer peripheral surface thereof are screwed into the housing of the steam turbine adjusting valve so as to face the end surface of the valve stem. The plurality of rods arranged so as to surround the valve rod are respectively inserted into the support plate arranged on the housing, and the housing is horizontally placed by the support plate via the plurality of rods screwed into the housing. The fixing position of the support plate in the axial direction of the rod is adjusted by a nut screwed to each rod, and the diameter of the cylinder rod that is supported by the support plate and can contact the valve rod is adjusted. the valve stem having a diameter small and is by hydraulic jacks having a hydraulic cylinder the valve stem end surface steam turbine pressure that presses, characterized in that removing the valve rod from said housing than A valve stem removal method of the valve.

According to the first and second aspects of the present invention, the valve stem can be pushed out of the housing with a large force generated by the thrust generating means, so that the labor for removing the valve stem is reduced. Further, since it is not necessary to hit the valve stem with a hammer or the like, it is not necessary to fix the housing to a large fixing device, and damage to the valve stem can be prevented.
Moreover, since the hydraulic jack is used, the valve stem can be removed from the housing with a little effort. Further, since the fixing position of the support plate with respect to the rod is variable, even if the extrusion stroke of the hydraulic jack is short, the pushing amount of the valve stem can be sufficiently secured by changing the fixing position of the support plate. Since the rod is connected to the housing by using the screw engagement of the rod with the housing, the connecting operation of the rod to the housing is surely and easily performed .

  Next, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 4 show an embodiment of the present invention. FIG. 4 shows a main part of the steam turbine control valve 1. The steam turbine control valve 1 is installed at the inlet of a high-pressure turbine in a thermal power plant or the like, and controls the output of the turbine by adjusting the flow rate of steam flowing from the boiler into the turbine. The steam turbine control valve 1 includes a housing (stand) 2, a valve box (valve box) 9, and a lever support 13. The housing 2 is located substantially at the center in the vertical direction of the steam turbine control valve 1, and the valve box 9 is located below the housing 2. The lever support 13 is located above the housing 2. A through hole 2 a extending in the up-down direction is formed in a substantially central portion of the housing 2. A central portion in the vertical direction of the housing 2 is formed in a concave portion 2b that is radially reduced in diameter. The housing 2 has cylindrical bushes 3 and 4 inside the through hole 2a. The bush 3 is press-fitted into the upper inner peripheral surface of the through hole 2a. The bush 4 is press-fitted into the lower inner peripheral surface of the through hole 2a. A valve rod 5 extending in the vertical direction is inserted inside the bush 3 and the bush 4 of the housing 2. The valve stem 5 is slidable in the axial direction (vertical direction) with respect to the housing 2.

  The lower end 2c of the housing 2 is formed on a protrusion 2c having substantially the same outer diameter as the recess 2b. The lower end part of the bush 4 is located inside the projection part 2c. The lower side of the valve stem 5 protrudes from the lower end surface of the bush 4. A substantially cylindrical guide 6 extending downward is fitted on the outer peripheral surface of the protrusion 2 c of the housing 2. The guide 6 is connected to the protruding portion 2c of the housing 2 through a connecting pin 6a. A substantially cylindrical valve cap 7 is attached to the lower end of the valve stem 5. A guide surface 6 b is formed on the lower inner surface of the guide 6 so as to be slidable with the outer peripheral surface of the valve cap 7. A valve body 8 is attached to the lower surface of the valve cap 7. A valve box 9 is located on the outer periphery of the guide 6 and the valve cap 7. The valve box 9 is connected to the housing 2 via a bolt 11. A hollow portion 9 a that houses the guide 6, the valve cap 7, and the valve body 8 is formed in the upper center portion of the valve box 9. The cavity 9a has a function as a passage through which steam passes. A passage 9b communicating with the cavity 9a is formed in the lower portion of the valve box 9. The valve body 8 is located between the hollow portion 9a of the valve box 9 and the passage 9b. A valve seat 10 is provided at a position facing the valve body 8. The valve seat 10 is press-fitted into the inner peripheral surface of the passage 9 b of the valve box 9. The valve body 8 can be in close contact with the valve seat 10. When the valve body 8 is in close contact with the valve seat 10, the cavity 9 a and the passage 9 b are blocked by the valve body 8.

  A lever support 13 is disposed on the upper end surface of the housing 2. The lever support 13 is fixed to the housing 2 via bolts 23. A cross head 14 is disposed inside the lever support 13. The lower side of the cross head 14 is connected to the upper end of the valve stem 5. A cylindrical spring retainer 16 is provided above the lever support 13. The lower end of the spring retainer 16 is fixed to the lever support 13 via a bolt 15. The ceiling wall 16a of the spring retainer 16 is composed of a thick plate member. The spring retainer 16 houses a first compression coil spring 18 having a large wire diameter. A second compression coil spring 19 having a smaller wire diameter than the first compression coil spring 18 is provided inside the first compression coil spring 18. A spring seat 20 made of a thick plate member is provided immediately above the cross head 14. A guide rod 17 is attached to the spring seat 20 and is located on the inner side of the second compression coil spring 19 and extends upward. The upper end of the first compression coil spring 18 and the upper end of the second compression coil spring 19 are in contact with the ceiling wall 16 a of the spring retainer 16. The lower end of the first compression coil spring 18 and the lower end of the second compression coil spring 19 are in contact with the spring seat 20. The first compression coil spring 18 and the second compression coil spring 19 are elastically deformable in the vertical direction, and are housed in the spring retainer 16 in a compressed state. The spring seat 20 presses the cross head 14 downward by the urging force of the first compression coil spring 18 and the second compression coil spring 19, whereby the valve element 8 is pressed against the valve seat 10 via the valve stem 5. It is in close contact.

  A lever 22 is connected to the cross head 14 via a pin 21. The end of the lever 22 is connected to a connecting plate 24 extending in the vertical direction via a pin 26. The upper end portion of the connecting plate 24 is connected to the lever 25 via a pin 27. The cross head 14 can move in the vertical direction in accordance with the movement of the lever 22, and when the cross head 14 moves upward due to the swing of the lever 22, the valve stem 5 moves upward and the valve The body 8 leaves the valve seat 10 and the steam turbine control valve 1 is opened.

  1 to 3 show a valve rod removal device 30 of a steam turbine control valve. The valve stem detaching device 30 includes a rod 31, a support plate 32, and a hydraulic jack 35 as thrust generating means. The support plate 32 is composed of a rectangular plate-like member having a predetermined thickness, and is disposed so as to face the end surface 5 a of the valve stem 5. As shown in FIG. 3, the support plate 32 is formed with four holes 33 arranged at a predetermined interval. The inner diameter of the hole 33 is slightly larger than the outer diameter of the rod 31. A rod 31 is inserted through each hole 33 of the support plate 32. The rod 31 is composed of a member that can sufficiently withstand a large tensile force. On the outer peripheral surface of each rod 31, a male screw 31a having the same diameter is formed over the entire length. One end of each rod 31 is screwed into a female screw 2 d formed in the housing 2. A nut 34 is screwed into a portion of the male screw 31 a between the other end of each rod 31 and the support plate 32. Each nut 34 has a function of preventing the movement of the support plate 32 and fixing the support plate 32 to the rod 31. The fixing position of the support plate 32 can be changed by changing the screwing position of the nut 34 with respect to the male screw 31 a of the rod 31.

  A hydraulic jack 35 serving as a thrust generating means is provided on the valve rod 5 side of the support plate 32. The hydraulic jack 35 includes a pump 36, a handle 37, a hydraulic cylinder 38, and a hydraulic hose 39. The hydraulic jack 35 has a function of advancing the cylinder rod 38 a by supplying oil discharged from the pump 36 by operation of the handle 37 to the hydraulic cylinder 38 via the hydraulic hose 39. The diameter of the cylinder rod 38 a is slightly smaller than the diameter of the valve stem 5. Thereby, the cylinder rod 38a can enter the bush 3. The hydraulic cylinder 38 is supported by the support plate 32 so that the cylinder rod 38 a faces the end surface 5 a of the valve stem 5.

  Next, a method for removing the valve stem 5 in the present embodiment will be described. The steam turbine control valve 1 is an important part that controls the output of the turbine, and is periodically disassembled for functional inspection. The steam turbine control valve 1 is disassembled in the following procedure. In FIG. 4, the lever support 13 is removed from the housing 2 by removing the bolts 23. Subsequently, the crosshead 14 attached to the tip of the valve stem 5 is removed, and the lever support 13 located on the upper side of the housing 2 is removed. Further, the valve box 9 is removed from the housing 2 by removing the bolts 11. Next, the housing 2 is set on the floor surface F in a horizontally placed state.

  FIG. 1 shows a state in which the valve box 9 and the lever support 13 are removed from the housing 2. In this state, the tip portion of the valve stem 5 protrudes from the housing 2. Removal of the valve stem 5 from the housing 2 is performed in the following procedure. First, one end of the rod 31 is screwed into each female screw 2d to which the bolt 23 is screwed. Since the male screw 31a having the same diameter as the female screw 2d is formed on the outer peripheral surface of the rod 31 over the entire length, one end of the rod 31 is reliably and easily connected to the housing 2 by screwing with the female screw 2d. The Thereafter, the cylinder 38 of the hydraulic jack 35 is disposed between the support plate 32 and the end surface 5 a of the valve stem 5. In this state, the hydraulic cylinder 38 is aligned so that the end surface of the cylinder rod 38 a faces the end surface 5 a of the valve stem 5. That is, the hydraulic cylinder 38 is aligned so that the axis of the cylinder rod 38 a matches the axis of the valve stem 5. Next, by operating the handle 37 of the hydraulic jack 35, oil is supplied from the pump 36 to the hydraulic cylinder 38. As a result, the cylinder rod 38a moves in the S1 direction, and the tip of the cylinder rod 38a approaches the end surface 5a of the valve stem 5.

  When the end surface of the cylinder rod 38a comes into contact with the end surface 5a of the valve rod 5, the pressure in the hydraulic cylinder 38 rises, and the valve rod 5 is pushed out by a large hydraulic force, and the valve cap attached to the valve rod 5 7 and the valve body 8 also move in the S2 direction. That is, the cylinder 38 is supported by the support plate 32, and the reaction force acting on the support plate 32 against the pushing force of the valve stem 5 acts on the housing 2 via each rod 31, so that the valve stem 5 is connected to the cylinder rod 38a. It will be pushed out of the housing 2 by the advance of. The valve stem 5 may be difficult to move in the axial direction with respect to the housing 2 due to the adhesion of the scale due to long-term use. By using the thrust of 38, the valve stem 5 can be reliably moved in the axial direction.

  Since the valve rod 5 is long in the axial direction, the length of the cylinder rod 38a of the hydraulic cylinder 38 must be increased in order to ensure a sufficient length of the valve rod 5 to be pushed out by the hydraulic cylinder 38. However, when the length of the cylinder rod 38a is increased, the cylinder rod 38a is likely to buckle. In this embodiment, the pushing length of the valve stem 5 is sufficiently secured by moving the support plate 32. Like to do. That is, after the cylinder rod 38a is extended to the maximum extent, the hydraulic cylinder 38 is removed, and the support plate 32 is advanced toward the valve stem 5 as shown by a two-dot chain line in FIG. The hydraulic cylinder 38 with the cylinder rod 38a retracted is disposed between the support plate 32 and the end face 5a of the valve rod 5, and the cylinder rod 38a is extended again by the oil supply from the pump 36, whereby the valve The extrusion length of the rod 5 is sufficiently secured. Even if the valve stem 5 is initially difficult to move relative to the housing 2, the valve stem 5 is easily moved relative to the housing 2 by being moved several times in the axial direction by the hydraulic cylinder 38. 5 can be taken out in the S2 direction.

  Thus, since the valve stem 5 can be removed from the housing 2 by the thrust of the hydraulic jack 35, the labor can be remarkably reduced as compared with the conventional method of removing the valve stem 5 by hitting it with a hammer or the like. Damage to the bar 5 can be prevented. Further, it is not necessary to fix the large housing 2 to a fixing device such as a vise, and workability can be improved.

  Although the embodiment of the present invention has been described in detail above, the specific configuration is not limited to the present embodiment, and even if there is a design change or the like without departing from the gist of the present invention, Included in the invention. For example, the thrust generating means is not limited to the hydraulic jack 35 and may be a screw jack using square screws. The fixing of the support plate 32 is not limited to the nut 34 screwed to the rod 31, and a configuration using a lock pin or the like may be used. Further, if a rod-like member for extrusion is inserted between the end surface 5a of the valve rod 5 and the end surface of the cylinder rod 38a, the valve rod 5 can be completely housed even in the hydraulic cylinder 38 having a short extrusion stroke. 2 can be extruded.

It is a schematic diagram of the valve rod detachment device of the steam turbine control valve concerning an embodiment of the invention. It is a front view of the rod and support plate in the apparatus of FIG. It is a top view of the support plate of FIG. It is a whole sectional view of the steam turbine control valve of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steam turbine adjusting valve 2 Housing 3 Bush 4 Bush 5 Valve rod 8 Valve body 9 Valve box 10 Valve seat 13 Lever support 14 Crosshead 16 Spring retainer 18 First compression coil spring 19 Second compression coil spring 20 Spring seat 30 Valve Rod removal device 31 Rod 31a Male screw 32 Support plate 35 Thrust generating means (hydraulic jack)
38 Hydraulic cylinder

Claims (2)

A plurality of rods each having an end that can be screwed into a plurality of internal threads formed in a housing of a steam turbine control valve into which a valve stem is inserted, and a male thread of the same diameter formed on the outer circumferential surface over the entire length in the axial direction ; ,
The plurality of rods, which are arranged to face the end surface of the valve stem, have a plurality of holes into which the plurality of rods arranged so as to surround the valve stem can be respectively inserted, and are screwed into the housing A support plate for supporting the housing in a horizontal state via
A nut screwed into the male screw of each rod, and the fixing position of the support plate in the axial direction of the rod being variable;
A hydraulic jack having a hydraulic cylinder supported by the support plate and capable of pressing the end face of the valve stem and having a diameter of a cylinder rod that can contact the valve stem is smaller than the diameter of the valve stem ;
A valve shaft detaching device for a steam turbine adjusting valve. The ends of a plurality of rods having male screws of the same diameter formed on the outer peripheral surface over the entire length in the axial direction are screwed into the housing of the steam turbine adjusting valve ,
The plurality of rods arranged so as to surround the valve rod are respectively inserted into a support plate arranged so as to face the end surface of the valve stem, and the plurality of rods screwed into the housing are inserted through the support rods. The housing is supported horizontally by a support plate,
Adjusting the fixing position of the support plate in the axial direction of the rod by a nut screwed to each rod;
The end face of the valve stem is pressed by a hydraulic jack having a hydraulic cylinder that is supported by the support plate and can contact the valve stem and has a diameter smaller than the diameter of the valve stem. A method for removing a valve stem of a steam turbine control valve, wherein the valve stem is removed from a housing.

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