Composite adjustment wide-load steam turbine bypass valve

Abstract

The invention discloses a composite adjustment wide-load steam turbine bypass valve, belongs to the technical field of power station valves, and aims to solve the problems that the load adjustment range of a steam turbine bypass valve is limited, and the stability is insufficient under the condition of frequent adjustment actions. Comprising a valve body, a first throttling sleeve is arranged between a valve cover and a valve seat, a large valve plug is arranged in the first throttling sleeve in a sliding mode, a second throttling sleeve and the large valve plug are sleeved inside and outside, a small valve plug is arranged at the lower end of the valve cover, the small valve plug is arranged in the second throttling sleeve in a sliding mode, and a plurality of throttling pressure reducing hole sets are formed in the first throttling sleeve. The second throttling sleeve is provided with a plurality of labyrinth pressure reducing hole groups, the large valve plug blocks or opens the plurality of throttling pressure reducing hole groups, and the small valve plug blocks or opens the plurality of labyrinth pressure reducing hole groups, the two pressure reducing units are arranged, and it can be ensured that the valve has the good control characteristic within the whole load range from small to large.

Description

Technical Field

[0001] The invention belongs to the technical field of power station valves, and in particular relates to a composite regulating wide-load turbine bypass valve. Background Art

[0002] The turbine bypass valve is an important valve in thermal power units that adjusts the steam pressure and temperature to specified values ​​in one valve. Its functions are: to control the steam pressure, temperature and flow rate during startup and shutdown to protect the steam turbine; to coordinate the steam flow balance between the steam turbine and the boiler to ensure the stable operation of the entire system; and to quickly open and bypass the steam in the event of a unit failure or emergency to protect the steam turbine and other equipment from damage.

[0003] At present, thermal power units are mainly responsible for coordinating the balance of the power grid, which requires the ability to flexibly adjust the power load. This requires the turbine bypass valve to have the ability to adjust a wide load, and to be able to operate for a long time under frequent adjustments and maintain performance stability.

[0004] The existing turbine bypass valves on the market are usually designed according to the startup conditions. First of all, they do not have the ability to adjust a wide load, and are not suitable for long-term operation under frequent operations. Problems such as excessive vibration and noise, loose closure, and even erosion and damage of valve internals often occur. Summary of the invention

[0005] The purpose of the present invention is to provide a wide-load steam turbine bypass valve with compound regulation to solve the problem that the load regulation range of the steam turbine bypass valve is limited and the stability is insufficient under frequent regulation actions. The technical solution adopted by the present invention is as follows: A wide-load steam turbine bypass valve with compound regulation comprises a valve body, a valve cover, a valve stem, a large valve plug, a first throttling sleeve, a second throttling sleeve, an actuator and a temperature reducing device assembly. The valve body is a three-way component. The upper opening, the lower opening and the side opening of the valve body are connected through an outer valve cavity. The lower opening of the valve body is a medium outlet, and the side opening of the valve body is a medium inlet. The valve cover seals the upper opening of the valve body. A valve seat is provided on the path of the medium outlet. A first sealing cone surface is provided on the inner circumference upper end of the valve seat. The medium outlet is connected to an outlet pipe, and a temperature reducing device assembly is provided on the outlet pipe. The first throttling sleeve comprises a plurality of interlayers which are sequentially sleeved inside and outside, the innermost interlayer is used as the main interlayer, and the other interlayers are used as auxiliary interlayers, the auxiliary interlayer is located at the bottom of the main interlayer, an annular gap is formed between two adjacent interlayers, the upper and lower ends of the interlayer located on the outer side are respectively abutted and connected with the adjacent inner interlayer to close the corresponding annular gap, a plurality of throttling and pressure reducing hole groups are axially opened on the side wall of the interlayer, and the plurality of throttling and pressure reducing hole groups of two adjacent interlayers are connected through the corresponding annular gap, the upper end of the main interlayer is sealed and connected to the valve cover, the lower end of the main interlayer is sealed and connected to the outer periphery of the valve seat, and the middle part of the main interlayer is provided with a first flow hole group; The large valve plug is a cylindrical component, and a second sealing cone surface is provided at the lower end of the outer circumference of the large valve plug. The outer circumference of the large valve plug is slidably matched with the inner circumference of the main interlayer. The large valve plug opens or blocks a plurality of throttling and pressure-reducing hole groups of the main interlayer. The second sealing cone surface abuts against the first sealing cone surface for sealing or separation. A second flow hole group is provided on the side wall of the large valve plug. A partition ring structure is provided at the inner circumference of the lower part of the large valve plug. A third sealing cone surface is provided at the upper end of the inner hole of the partition ring structure. The second throttling sleeve is provided with an inner valve cavity with a lower opening. The upper end of the outer circumference of the second throttling sleeve is connected to the inner circumference of the large valve plug. The second throttling sleeve is connected to the The partition ring structure is coaxially abutted against each other up and down, and an annular cavity is formed between the outer periphery of the second throttling sleeve and the inner periphery of the large valve plug. The lower part of the second throttling sleeve is axially provided with a plurality of labyrinth pressure reducing hole groups, and a small valve plug is provided at the lower end of the valve stem. The outer periphery of the small valve plug is slidably matched with the inner periphery of the second throttling sleeve, and a fourth sealing cone surface is provided at the lower end of the outer periphery of the small valve plug. The small valve plug opens or blocks a plurality of labyrinth pressure reducing hole groups, and the third sealing cone surface abuts against the fourth sealing cone surface for sealing or separation. The flow area of ​​the plurality of throttling pressure reducing hole groups on each of the interlayers is greater than the flow area of ​​the plurality of labyrinth pressure reducing hole groups.

[0006] Furthermore, the second throttling sleeve includes a disc cover, a plurality of labyrinth rings and a ring seat, the disc cover is provided with a cavity with a lower opening, the ring seat is an annular structure, the outer circumferences of the disc cover, the plurality of labyrinth rings and the ring seat are equal, the inner circumferences of the disc cover and the plurality of labyrinth rings are equal, the disc cover, the plurality of labyrinth rings, the ring seat and the spacer ring structure are coaxially abutted against each other from top to bottom, and the upper end surfaces of the labyrinth ring and the ring seat are circumferentially provided with a plurality of pressure reducing grooves connecting the inner circumference and the outer circumference, and the pressure reducing grooves are provided with a plurality of right-angle turning structures.

[0007] Furthermore, the order of the right-angle turn structure is determined by the following formula: ; Where: n w is the order of the right-angle turn structure, dimensionless; ΔP It is the pressure difference between the medium outlet and the medium inlet, in Pa; ξw is the drag coefficient of the right-angle turn structure, dimensionless; ρ is the average density of steam, in kg / m 3 ; υ is the steam velocity in m / s.

[0008] Furthermore, assuming that the total number of the labyrinth rings and the ring seats is n1, and the number of the pressure relief grooves on the labyrinth rings or the number of the pressure relief grooves on the ring seats is n2, the inlet cross-sectional area of ​​the pressure relief groove is determined by the following formula: ; Where: A m is the inlet cross-sectional area of ​​the pressure reducing tank, in m 2 ; K vm is the flow coefficient of the labyrinth disk group, in m 3 / h.

[0009] Furthermore, if the ratio of the outlet pressure to the inlet pressure of the plurality of throttling and pressure-reducing hole groups of each interlayer is greater than or equal to the critical pressure ratio of steam 0.546, then the number of stages of the interlayer n k Determined by the following formula: ; Where: n k is the number of the interlayer, an integer, dimensionless; P2 is the pressure at the outlet of the medium, in Pa; P1 is the pressure of the medium inlet, in Pa; Resistance coefficient of several throttling and pressure reducing hole groups on the single-stage interlayer ξ K It is the ratio function of the flow area of ​​several throttling and pressure-reducing hole groups to the inner hole area of ​​the valve seat. ξ K Determined by the following formula: ;

[0010] Where: A K is the flow area of ​​several throttling and pressure-reducing hole groups, in m 2 ; A F is the inner hole area of ​​the valve seat, in m 2 ; The resistance coefficient of the first throttling sleeve is the resistance coefficient of the throttling and pressure-reducing hole groups on each level of the interlayer and , then the flow coefficient of the first throttle sleeve is determined by the following formula; ;

[0011] Where: k VT is the flow coefficient of the first throttling sleeve, m 3 / h.

[0012] The large valve plug includes an upper plug body and a lower plug body. The lower end of the upper plug body matches the upper end stop of the lower plug body and is connected by screws. The upper end of the outer periphery of the second throttling sleeve is connected to the inner periphery of the upper plug body, and a spacer ring structure is arranged on the inner periphery of the lower plug body.

[0013] Furthermore, a disc spring assembly and a disc spring pressure cover are sleeved on the valve stem, the disc spring pressure cover is connected to the valve stem pin, the upper end of the disc spring assembly abuts against the disc spring pressure cover, and the lower end of the disc spring assembly abuts against the second throttling sleeve.

[0014] Furthermore, a limit cover is provided at the upper end of the large valve plug.

[0015] Furthermore, a first flange seat and a second flange seat are respectively arranged on opposite sides of the outlet pipe, the water spray pipe body horizontally penetrates the outlet pipe, one end of the water spray pipe body is connected to one end of the water spray pipe seat, the other end of the water spray pipe body is inserted into the second flange seat, the end cover seals the second flange seat, the flange structure on the outer periphery of the water spray pipe seat is connected to the first flange seat, the other end of the water spray pipe seat is connected to the connecting flange, a plurality of spring nozzles are arranged on the water spray pipe body, the plurality of spring nozzles are divided into multiple groups, and the opening pressures of the multiple groups of spring nozzles change sequentially.

[0016] Furthermore, a drain pipe seat is provided on the side wall of the outer valve cavity.

[0017] Furthermore, a stuffing box is provided on the valve cover, and a stuffing gland presses the stuffing assembly onto the bottom surface of the stuffing box, and the valve stem and the valve cover are slidably sealed through the stuffing assembly.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention is provided with two sets of pressure reducing units. Under the working condition of small load, by adjusting the lifting height of the valve stem, the steam is made to flow through the first flow hole group, the second flow hole group, the annular cavity and the plurality of labyrinth pressure reducing hole groups in sequence. By adjusting the number of the plurality of labyrinth flow passages opened, the steam pressure is precisely regulated under small flow rate. Under the working condition of large load, by adjusting the lifting height of the valve stem, the steam is made to flow through the plurality of throttling pressure reducing hole groups on the interlayer in sequence. Since the flow area of ​​the plurality of throttling pressure reducing hole groups on each interlayer is much larger than the flow area of ​​the plurality of labyrinth pressure reducing hole groups, the stable regulation of the steam pressure under large flow rate can be ensured. This composite regulation method can ensure that the valve has good control characteristics in the entire load range from small to large.

[0019] 2. Several spring nozzles are divided into multiple groups, and the opening pressures of multiple groups of spring nozzles change in sequence. In order to meet the requirements of wide load adjustment of turbine bypass valves, these spring nozzles are not opened with nozzles with the same opening pressure and rated flow, but are designed as a group of nozzles with multiple models and quantities according to the requirements of cooling water flow and pressure under different working conditions. As the valve working conditions change, nozzles of different models are gradually opened, so the temperature regulation performance is more excellent. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a schematic diagram of the structure of the valve body; Figure 3 It is a structural diagram of the valve seat; Figure 4 is a schematic diagram of the structure of the first throttle sleeve; Figure 5 It is a schematic diagram of the coordination of the large valve plug, the valve stem and the second throttling sleeve; Figure 6 is a schematic diagram of the structure of the second throttle sleeve; Figure 7 It is a partial schematic diagram of the lower end of the valve stem; Figure 8 This is a top view of the maze disk; Fig. 9 It is a schematic diagram of the desuperheater assembly installed on the outlet pipe.

[0021] In the figure, 1. valve body, 2. valve seat, 3. first throttling sleeve, 4. second throttling sleeve, 5. large valve plug, 6. valve cover, 7. packing assembly, 8. coupling positioning plate, 9. valve stem, 10. actuator, 11. drain pipe seat, 12. reducer, 13 outlet pipe, 14. cooling device assembly, 15. medium inlet, 16. medium outlet, 17. outer valve cavity, 18. main interlayer, 19. auxiliary interlayer, 20. first flow hole group, 21. first sealing cone surface, 22. throttling and pressure reduction hole group, 23. fourth sealing cone surface, 24. upper plug body, 25. second flow hole group, 26. lower plug body, 27. small valve plug, 28. spacer ring structure, 29. second sealing cone surface, 30. third sealing cone surface, 31. disc spring group, 32. Disc spring gland, 33. Limiting cover, 34. Inner valve chamber, 35. Disc gland, 36. Labyrinth ring, 37. Ring seat, 38. Pressure reducing groove, 39. Spray pipe body, 40. Connecting flange, 41. Spray pipe seat, 42. First flange seat, 43. Spring nozzle, 44. Second flange seat, 45. End cover, 46. Inlet pipe, 47. Column. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described below by the specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0023] The connection mentioned in the present invention is divided into fixed connection and detachable connection. The fixed connection is a non-detachable connection including but not limited to conventional fixed connection methods such as folding connection, rivet connection, bonding connection and welding connection. The detachable connection includes but not limited to conventional detachable methods such as bolt connection, snap connection, pin connection and hinge connection. When the specific connection method is not clearly defined, it is assumed that at least one connection method can be found in the existing connection methods to achieve the function, and those skilled in the art can choose according to their needs. For example: welding connection is selected for fixed connection, and bolt connection is selected for detachable connection.

[0024] The present invention will be further described in detail below in conjunction with the accompanying drawings. The following embodiments are provided to explain the present invention, but the present invention is not limited to the following embodiments.

[0025] Example: Figures 1 to 9 As shown, a wide load steam turbine bypass valve with composite regulation includes a valve body 1, a valve cover 6, a valve stem 9, a large valve plug 5, a first throttling sleeve 3, a second throttling sleeve 4, an actuator 10 and a temperature reduction device assembly 14. The valve body 1 is a three-way component. The upper opening, the lower opening and the side opening of the valve body 1 are connected through an outer valve cavity 17. The lower opening of the valve body 1 is a medium outlet 16, and the side opening of the valve body 1 is a medium inlet 15. The valve cover 6 seals the upper opening of the valve body 1. The diameter of the medium outlet 16 is provided with a A valve seat 2 is provided, a first sealing cone 21 is provided at the inner circumferential upper end of the valve seat 2, a medium outlet 16 is connected with a reducer 12 and an outlet pipe 13 in sequence, a temperature reducing device assembly 14 is provided on the outlet pipe 13, a medium inlet 15 is connected with an inlet pipe 46, an actuator 10 is supported above a valve cover 6 by a plurality of columns 47, an upper end of a valve stem 9 passes through the valve cover 6, and is connected with an output end of the actuator 10 by a coupling positioning plate 8, and the coupling positioning plate 8 is slidably matched with any column 47; The first throttling sleeve 3 includes a plurality of interlayers which are sequentially sleeved inside and outside, the innermost interlayer is used as the main interlayer 18, and the other interlayers are used as the auxiliary interlayer 19, the auxiliary interlayer 19 is located at the bottom of the main interlayer 18, and an annular gap is formed between the two adjacent interlayers, and the upper and lower ends of the interlayer located on the outside are respectively abutted and connected with the adjacent inner interlayer to close the corresponding annular gap, and a plurality of throttling and pressure reducing hole groups 22 are axially opened on the side wall of the interlayer, and the throttling and pressure reducing hole groups 22 are composed of a plurality of pressure reducing circular holes arranged circumferentially, and the plurality of throttling and pressure reducing hole groups 22 of two adjacent interlayers are connected through the corresponding annular gap, the upper end of the main interlayer 18 is sealed and connected to the valve cover 6, and the lower end of the main interlayer 18 is sealed and connected to the outer periphery of the valve seat 2, and the middle part of the main interlayer 18 is provided with a first flow hole group 20; The large valve plug 5 is a cylindrical component. A second sealing cone surface 29 is provided at the lower end of the outer circumference of the large valve plug 5. The outer circumference of the large valve plug 5 is slidably matched with the inner circumference of the main interlayer 18. The height of the main interlayer 18 is greater than the height of the large valve plug 5. There is space in the main interlayer 18 for the large valve plug 5 to slide up and down. The large valve plug 5 opens or blocks several throttling and pressure reducing hole groups 22 of the main interlayer 18. The second sealing cone surface 29 abuts against or separates from the first sealing cone surface 21. A second flow hole group 25 is provided on the side wall of the large valve plug 5. A partition ring structure 28 is provided at the inner circumference of the lower part of the large valve plug 5. A third sealing cone surface 30 is provided at the upper end of the inner hole of the partition ring structure 28. The second throttling sleeve 4 is provided with an inner valve cavity 34 with a lower opening. The upper end of the outer circumference of the second throttling sleeve 4 is connected to the inner circumference of the large valve plug 5. The second throttling sleeve 4 and the partition ring structure 28 are coaxially abutted against each other up and down, and an annular cavity is formed between the outer circumference of the second throttling sleeve 4 and the inner circumference of the large valve plug 5. A plurality of labyrinth pressure reducing hole groups are axially arranged at the lower part of the second throttling sleeve 4, and the labyrinth pressure reducing hole groups are composed of a plurality of labyrinth flow channels arranged circumferentially. A small valve plug 27 is arranged at the lower end of the valve stem 9, and the outer periphery of the small valve plug 27 is slidably matched with the inner periphery of the second throttling sleeve 4. The height of the inner valve cavity 34 is greater than the height of the small valve plug 27, and there is space in the inner valve cavity 34 for the small valve plug 27 to slide up and down. A fourth sealing cone surface 23 is arranged at the lower end of the outer periphery of the small valve plug 27, and the small valve plug 27 opens or blocks a plurality of labyrinth pressure reducing hole groups. The third sealing cone surface 30 is abutted against the fourth sealing cone surface 23 for sealing or separation. The flow area of ​​the first through-flow hole group 20 is equal to the flow area of ​​the second through-flow hole group 25, and the flow area of ​​the second through-flow hole group 25 is greater than the flow area of ​​the plurality of labyrinth pressure reducing hole groups. The flow area of ​​the plurality of throttling pressure reducing hole groups 22 on each of the interlayers is greater than the flow area of ​​the plurality of labyrinth pressure reducing hole groups.

[0026] When the valve is completely closed, the first flow hole group 20 is aligned with the second flow hole group 25, the first sealing cone surface 21 is sealed against the second sealing cone surface 29, the outer periphery of the large valve plug 5 blocks the plurality of throttling and pressure reducing hole groups 22 of the main interlayer 18, the outer valve cavity 17 is connected with the annular cavity through the first flow hole group 20 and the second flow hole group 25 in sequence, the third sealing cone surface 30 is sealed against the fourth sealing cone surface 23, and the outer periphery of the small valve plug 27 closes the plurality of labyrinth pressure reducing hole groups; When the actuator 10 lifts the valve stem 9 upward, the small valve plug 27 slides up first, the third sealing cone 30 and the fourth sealing cone 23 are separated, and several labyrinth pressure reducing hole groups are opened in sequence, and the medium inlet 15, the outer valve chamber 17, the first flow hole group 20, the second flow hole group 25, the annular chamber, several labyrinth pressure reducing holes, the inner hole of the partition ring structure 28 and the medium outlet 16 are connected in sequence until the small valve plug 27 slides up to the top of the inner valve chamber 34 and abuts against the second throttling sleeve 4. Then when the actuator 10 continues to lift the valve stem 9 upward, the large valve plug 5 slides up with the valve stem 9, the first flow hole group 20 and the second flow hole group 25 are misaligned, the first sealing cone 21 and the second sealing cone 29 are separated, and several throttling pressure reducing hole groups 22 of the main interlayer 18 are opened in sequence, and the medium inlet 15, the outer valve chamber 17, several throttling pressure reducing hole groups 22 on the interlayer, the inner hole of the valve seat 2 and the medium outlet 16 are connected in sequence.

[0027] The present invention is provided with two sets of pressure reducing units. Under the working condition of light load, by adjusting the lifting height of the valve stem 9, the steam is made to flow through the first flow hole group 20, the second flow hole group 25, the annular cavity and a plurality of labyrinth pressure reducing hole groups in sequence. By adjusting the number of the labyrinth flow channels opened, the precise regulation of the steam pressure at a small flow rate is achieved. Under the working condition of heavy load, by adjusting the lifting height of the valve stem 9, the steam is made to flow through the throttling pressure reducing hole groups 22 on the plurality of interlayers in sequence. Since the flow areas of the plurality of throttling pressure reducing hole groups 22 on each of the interlayers are much larger than the flow areas of the plurality of labyrinth pressure reducing hole groups, the stable regulation of the steam pressure at a large flow rate can be guaranteed. This composite regulation method can ensure that the valve has good control characteristics in the entire load range from small to large.

[0028] The second throttling sleeve 4 includes a disc gland 35, a plurality of labyrinth rings 36 and a ring seat 37. The disc gland 35 is provided with a cavity with a lower opening. The ring seat 37 is an annular structure. The outer peripheries of the disc gland 35, the plurality of labyrinth rings 36 and the ring seat 37 are equal, and the inner peripheries of the disc gland 35 and the plurality of labyrinth rings 36 are equal. The disc gland 35, the plurality of labyrinth rings 36, the ring seat 37 and the partition ring structure 28 are coaxially abutted from top to bottom in sequence. The upper end surfaces of the labyrinth rings 36 and the ring seat 37 are circumferentially provided with a plurality of pressure reducing grooves 38 connecting the inner periphery and the outer periphery. The pressure reducing grooves 38 are blocked by the components abutting at the upper ends to form a labyrinth flow channel. With such an arrangement, the plurality of labyrinth flow channels can form mutually unconnected parallel flow channels, which can evenly share the flow rate of steam. The pressure reducing grooves 38 are provided with a plurality of right-angle turning structures. When the steam flows through the right-angle turning, energy is consumed to complete the pressure reduction.

[0029] The degree of the right-angle turn structure is determined by the following formula: ; Where: n w is the order of the right-angle turn structure, dimensionless; ΔP is the pressure difference between the medium outlet 16 and the medium inlet 15, in Pa; ξ w is the drag coefficient of the right-angle turn structure, which is related to the geometric dimensions and roughness of the labyrinth flow channel and can be obtained through experiments and is dimensionless; ρ is the average density of steam, in kg / m 3 ; υ is the steam velocity in m / s.

[0030] Assuming that the total number of the labyrinth rings 36 and the ring seat 37 is n1, and the number of the pressure reducing grooves 38 on the labyrinth ring 36 or the number of the pressure reducing grooves 38 on the ring seat 37 is n2, the inlet cross-sectional area of ​​the pressure reducing groove 38 is determined by the following formula: ; Where: A m is the inlet cross-sectional area of ​​the pressure reducing tank 38, in m 2 ; K vm is the flow coefficient of the labyrinth disk group, in m 3 / h, the value is given by the design.

[0031] The ratio of the outlet pressure to the inlet pressure of the throttling and pressure reducing hole groups 22 of each interlayer is greater than or equal to the critical pressure ratio of steam 0.546, then the number of stages of the interlayer n k Determined by the following formula: ; Where: n k is the number of the interlayer, an integer, dimensionless; P2 is the pressure at the medium outlet 16, in Pa; P1 is the pressure of the medium inlet 15, in Pa; The resistance coefficient of the plurality of throttling and pressure reducing hole groups 22 on the single-stage interlayer ξ K is the ratio function of the flow area of ​​the plurality of throttling and pressure reducing hole groups 22 to the inner hole area of ​​the valve seat 2, ξ K Determined by the following formula: ;

[0032] Where: A K is the flow area of ​​several throttling and pressure reducing hole groups 22, in m 2 ; A F is the inner hole area of ​​valve seat 2, in m 2 ; The first throttling sleeve 3 can be regarded as a plurality of throttling and pressure reducing hole groups 22 on the multi-stage interlayer connected in series. The resistance coefficient of the first throttling sleeve 3 is the sum of the resistance coefficients of the plurality of throttling and pressure reducing hole groups 22 on the interlayers at each stage. , then the flow coefficient of the first throttling sleeve 3 is determined by the following formula; ;

[0033] Where: k VT is the flow coefficient of the first throttling sleeve 3, m 3 / h.

[0034] Through the above formulas n w , A m , n k , ξ K , k VT Parameters such as the above are calculated, and then the bypass valve is designed according to the calculation results, so that a bypass valve with excellent performance that is highly matched with actual working conditions can be obtained.

[0035] The large valve plug 5 includes an upper plug body 24 and a lower plug body 26. The lower end of the upper plug body 24 and the upper end stopper of the lower plug body 26 are matched and connected by screws. The upper end of the outer periphery of the second throttling sleeve 4 is connected to the inner periphery of the upper plug body 24, and the spacer ring structure 28 is arranged on the inner periphery of the lower plug body 26.

[0036] The valve stem 9 is sleeved with a disc spring assembly 31 and a disc spring pressure cover 32 . The disc spring pressure cover 32 is pin-connected to the valve stem 9 . The upper end of the disc spring assembly 31 abuts against the disc spring pressure cover 32 , and the lower end of the disc spring assembly 31 abuts against the second throttling sleeve 4 .

[0037] A limit cover 33 is provided at the upper end of the large valve plug 5. When the small valve plug 27 slides up to the top of the inner valve cavity 34, the limit cover 33 and the disc spring pressure cover 32 abut against each other up and down.

[0038] A first flange seat 42 and a second flange seat 44 are respectively provided on opposite sides of the outlet pipe 13. The water spray pipe body 39 horizontally penetrates the outlet pipe 13. One end of the water spray pipe body 39 is connected to one end of the water spray pipe seat 41. The other end of the water spray pipe body 39 is inserted into the second flange seat 44. The end cover 45 seals the second flange seat 44. The flange structure on the outer periphery of the water spray pipe seat 41 is connected to the first flange seat 42. The other end of the water spray pipe seat 41 is connected to the connecting flange 40. A plurality of spring nozzles 43 are arranged on the water spray pipe body 39. The spring nozzle 43 is consistent with the atomizing nozzle structure disclosed in the utility model patent with announcement number CN216173341U. Under the action of the cooling water pressure, the compression spring of the spring nozzle 43 is pushed open, the nozzle is opened, and the cooling water is atomized and sprayed out through the small holes on the nozzle to form tiny droplets. After the droplets are ejected, they absorb the heat of the steam and then vaporize quickly, reducing the steam to a suitable temperature. The spring nozzles 43 are divided into multiple groups, and the opening pressures of the multiple groups of spring nozzles 43 change in sequence. In order to meet the requirements of wide load adjustment of the turbine bypass valve, these spring nozzles 43 are not opened with nozzles with the same opening pressure and rated flow, but are designed as a group of nozzles with multiple models and quantities according to the requirements of the cooling water flow and pressure under different working conditions. As the valve working conditions change, nozzles of different models are gradually opened, so the temperature regulation performance is more excellent.

[0039] A drain pipe seat 11 is provided on the side wall of the outer valve chamber 17 .

[0040] A stuffing box is provided on the valve cover 6 , and a stuffing gland presses the stuffing assembly 7 onto the bottom surface of the stuffing box. The valve stem 9 and the valve cover 6 are slidably sealed through the stuffing assembly 7 .

[0041] The above embodiments are merely exemplary descriptions of the present invention and do not limit its protection scope. Those skilled in the art may also make partial changes thereto, which are within the protection scope of the present invention as long as they do not exceed the spirit of the present invention.

Claims

1. A composite regulating wide load turbine bypass valve, characterized in that: The valve body (1) comprises a valve body (1), a valve cover (6), a valve stem (9), a large valve plug (5), a first throttling sleeve (3), a second throttling sleeve (4), an actuator (10) and a temperature reducing device assembly (14). The valve body (1) is a three-way component. The upper opening, the lower opening and the side opening of the valve body (1) are connected through an outer valve cavity (17). The lower opening of the valve body (1) is a medium outlet (16). The side opening of the valve body (1) is a medium inlet (15). The valve cover (6) seals the upper opening of the valve body (1). A valve seat (2) is provided on the path of the medium outlet (16). The inner circumference upper end of the valve seat (2) is provided with a first sealing cone surface (21). The medium outlet (16) is connected to an outlet pipe (13). The outlet pipe (13) is provided with a temperature reducing device assembly (14). The first throttling sleeve (3) comprises a plurality of interlayers which are sequentially sleeved inside and outside, the innermost interlayer being a main interlayer (18), and the other interlayers being auxiliary interlayers (19), the auxiliary interlayer (19) being located at the bottom of the main interlayer (18), an annular gap being formed between two adjacent interlayers, the upper and lower ends of the interlayer located on the outer side being respectively abutted against and connected to the adjacent inner interlayer to close the corresponding annular gap, a plurality of throttling and pressure reducing hole groups (22) being axially opened on the side wall of the interlayer, the plurality of throttling and pressure reducing hole groups (22) of two adjacent interlayers being connected through the corresponding annular gap, the upper end of the main interlayer (18) being sealedly connected to the valve cover (6), the lower end of the main interlayer (18) being sealedly connected to the outer periphery of the valve seat (2), and a first flow hole group (20) being provided in the middle of the main interlayer (18); The large valve plug (5) is a cylindrical component. The lower end of the outer circumference of the large valve plug (5) is provided with a second sealing cone surface (29). The outer circumference of the large valve plug (5) is slidably matched with the inner circumference of the main interlayer (18). The large valve plug (5) opens or blocks a plurality of throttling and pressure reducing hole groups (22) of the main interlayer (18). The second sealing cone surface (29) is abutted and sealed or separated from the first sealing cone surface (21). A second flow hole group (25) is provided on the side wall of the large valve plug (5). The lower inner circumference of the large valve plug (5) is provided with a partition ring structure (28). The upper end of the inner hole of the partition ring structure (28) is provided with a third sealing cone surface (30). The second throttling sleeve (4) is provided with an inner valve cavity (34) with a lower opening. The upper end of the outer circumference of the second throttling sleeve (4) is in contact with the inner circumference of the large valve plug (5). The second throttling sleeve (4) and the partition ring structure (28) are coaxially abutted against each other up and down, an annular cavity is formed between the outer periphery of the second throttling sleeve (4) and the inner periphery of the large valve plug (5), a plurality of labyrinth pressure reducing hole groups are axially arranged at the lower part of the second throttling sleeve (4), a small valve plug (27) is arranged at the lower end of the valve stem (9), the outer periphery of the small valve plug (27) is slidably matched with the inner periphery of the second throttling sleeve (4), a fourth sealing cone surface (23) is arranged at the lower end of the outer periphery of the small valve plug (27), the small valve plug (27) opens or blocks the plurality of labyrinth pressure reducing hole groups, the third sealing cone surface (30) abuts against the fourth sealing cone surface (23) to seal or separate, and the flow area of ​​the plurality of throttling pressure reducing hole groups (22) on each of the interlayers is greater than the flow area of ​​the plurality of labyrinth pressure reducing hole groups.

2. A compound-regulated wide-load steam turbine bypass valve according to claim 1, characterized in that: The second throttle sleeve (4) comprises a disc gland (35), a plurality of labyrinth rings (36) and a ring seat (37); the disc gland (35) is provided with a cavity with a lower opening; the ring seat (37) is an annular structure; the outer circumferences of the disc gland (35), the plurality of labyrinth rings (36) and the ring seat (37) are equal; the inner circumferences of the disc gland (35) and the plurality of labyrinth rings (36) are equal; the disc gland (35), the plurality of labyrinth rings (36), the ring seat (37) and the spacer ring structure (28) are coaxially opposed to each other in sequence from top to bottom; the upper end surfaces of the labyrinth ring (36) and the ring seat (37) are circumferentially provided with a plurality of pressure reducing grooves (38) communicating with the inner circumference and the outer circumference; the pressure reducing grooves (38) are provided with a plurality of right-angle turning structures.

3. A compound-regulated wide-load steam turbine bypass valve according to claim 2, characterized in that: The degree of the right-angle turn structure is determined by the following formula: ； Where: n w is the order of the right-angle turn structure, dimensionless; ΔP is the pressure difference between the medium outlet (16) and the medium inlet (15), in Pa; ξ w is the drag coefficient of the right-angle turn structure, dimensionless; ρ is the average density of steam, in kg / m 3 ; υ is the steam velocity in m / s; Assuming that the total number of the labyrinth rings (36) and the ring seat (37) is n1, and the number of the pressure reducing grooves (38) on the labyrinth ring (36) or the number of the pressure reducing grooves (38) on the ring seat (37) is n2, the inlet cross-sectional area of ​​the pressure reducing groove (38) is determined by the following formula: ； Where: A m is the inlet cross-sectional area of ​​the pressure reducing tank (38), in m 2 ; K vm is the flow coefficient of the labyrinth disk group, in m 3 / h.

4. A compound-regulated wide-load steam turbine bypass valve according to claim 3, characterized in that: If the ratio of the outlet pressure to the inlet pressure of the plurality of throttling and pressure reducing hole groups (22) of each interlayer is greater than or equal to the critical pressure ratio of steam 0.546, then the number of stages of the interlayer n k Determined by the following formula: ； Where: n k is the number of the interlayer, an integer, dimensionless; P2 is the pressure at the medium outlet (16), in Pa; P1 is the pressure at the medium inlet (15), in Pa; Resistance coefficient of a plurality of throttling and pressure reducing hole groups (22) on the single-stage interlayer ξ K is a function of the ratio of the flow area of ​​the plurality of throttling and pressure reducing hole groups (22) to the inner hole area of ​​the valve seat (2), ξ K Determined by the following formula: ； Where: A K is the flow area of ​​the throttling and pressure reducing hole groups (22), in m 2 ; A F is the inner hole area of ​​the valve seat (2), in m 2 ; The resistance coefficient of the first throttling sleeve (3) is the sum of the resistance coefficients of the plurality of throttling and pressure reducing hole groups (22) on each level of the interlayer. , then the flow coefficient of the first throttling sleeve (3) is determined by the following formula: ； Where: k VT is the flow coefficient of the first throttling sleeve (3), m 3 / h.

5. The compound-regulated wide-load steam turbine bypass valve according to claim 1, characterized in that: The large valve plug (5) comprises an upper plug body (24) and a lower plug body (26); the lower end of the upper plug body (24) and the upper end stopper of the lower plug body (26) are matched and connected by screws; the upper end of the outer periphery of the second throttling sleeve (4) is connected to the inner periphery of the upper plug body (24); and the spacer ring structure (28) is arranged on the inner periphery of the lower plug body (26).

6. The compound-regulated wide-load steam turbine bypass valve according to claim 1, characterized in that: A disc spring assembly (31) and a disc spring cover (32) are sleeved on the valve stem (9). The disc spring cover (32) is pin-connected to the valve stem (9). The upper end of the disc spring assembly (31) abuts against the disc spring cover (32), and the lower end of the disc spring assembly (31) abuts against the second throttling sleeve (4).

7. A compound-regulated wide-load steam turbine bypass valve according to claim 6, characterized in that: A limit cover (33) is provided at the upper end of the large valve plug (5).

8. The compound-regulated wide-load steam turbine bypass valve according to claim 1, characterized in that: A first flange seat (42) and a second flange seat (44) are respectively arranged on opposite sides of the outlet pipe (13); a water spray pipe body (39) horizontally penetrates the outlet pipe (13); one end of the water spray pipe body (39) is connected to one end of the water spray pipe seat (41); the other end of the water spray pipe body (39) is inserted into the second flange seat (44); an end cover (45) seals the second flange seat (44); a flange structure on the outer periphery of the water spray pipe seat (41) is connected to the first flange seat (42); the other end of the water spray pipe seat (41) is connected to the connecting flange (40); a plurality of spring nozzles (43) are arranged on the water spray pipe body (39); the plurality of spring nozzles (43) are divided into a plurality of groups; and the opening pressures of the plurality of groups of spring nozzles (43) vary sequentially.

9. The compound-regulated wide-load steam turbine bypass valve according to claim 1, characterized in that: A drain pipe seat (11) is provided on the side wall of the outer valve chamber (17).

10. A compound-regulated wide-load steam turbine bypass valve according to any one of claims 1 to 9, characterized in that: A stuffing box is provided on the valve cover (6), and a stuffing gland presses a stuffing assembly (7) onto the bottom surface of the stuffing box. The valve stem (9) and the valve cover (6) are slidably sealed via the stuffing assembly (7).

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