CN218094466U - Medium self-driven main steam safety valve for nuclear power plant - Google Patents
Medium self-driven main steam safety valve for nuclear power plant Download PDFInfo
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- CN218094466U CN218094466U CN202220942351.4U CN202220942351U CN218094466U CN 218094466 U CN218094466 U CN 218094466U CN 202220942351 U CN202220942351 U CN 202220942351U CN 218094466 U CN218094466 U CN 218094466U
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Abstract
The utility model belongs to nuclear power plant valve engineering design field, concretely relates to nuclear power plant is with medium self-driven owner steam relief valve. The pilot valve comprises a main valve, a pilot valve group and a pilot valve, wherein the main valve is respectively connected with the pilot valve group and the pilot valve. The main valve comprises a valve cover, the valve cover is connected with the valve body through a fastening piece and sealed by a sealing gasket, the valve core is arranged in the valve body and provided with a rod-shaped part, a middle bulge part and a head part, a flow channel is arranged in the valve core, and the piston cylinder is sleeved outside the middle bulge part of the valve core and provides guidance for the movement of the valve core. The beneficial effects are that: the time difference exists between the action of the pilot valve and the action of the main valve, so that the main valve can be prevented from frequently acting under the transient states of phase change of a medium, transient system pressure and the like, the fault mode that water hammer cannot return to a seat is avoided, and the running reliability of the safety valve under the complex medium working condition is effectively improved.
Description
Technical Field
The utility model belongs to nuclear power plant valve engineering design field, concretely relates to nuclear power plant is with medium self-driven owner steam relief valve.
Background
The main steam safety valve is a key device for overpressure protection of the steam generator and the main steam pipeline of the nuclear power station, prevents the steam generator and the main steam pipeline from being subjected to overpressure damage under transient or accident conditions, ensures the integrity of a pressure boundary of the two loops, and belongs to nuclear safety related devices.
In a nuclear power station with million kilowatt level electric power, the steam flow of a single steam generator can reach more than 1400t/h, in order to meet the steam discharge flow requirement of overpressure protection of the steam generator and a main steam pipeline, 6-7 spring-loaded safety valves which are operated in parallel are mostly arranged on the main steam pipeline at the outlet of each steam generator in domestic and foreign nuclear power stations, the reason is that the single valve displacement is small, a plurality of safety valves are required to be configured to meet the capacity requirement, the failure of the safety valves is considered according to the principle of 'single failure', redundant configuration is required, and the safety valves are required to be divided into two to three groups according to different action pressures in order to prevent the valve core from vibrating.
Practical engineering experience shows that spring-loaded safety valves have the following major disadvantages:
1) Under the accident condition of steam generator heat transfer pipe breakage, the medium of the main steam system is no longer single saturated steam, the medium may be in the states of saturated steam, saturated water, steam-liquid and the like and accompanied with the phase change of the medium, and the spring loaded safety valve is easy to generate frequency jump, vibration and even open faults when running under the complex medium state, so that accident superposition is caused, and the difficulty of treatment and relief is increased.
2) As the system pressure increases, the leak tightness deteriorates, and the main steam pressure fluctuation directly affects the tightness of the safety valve.
3) The set value of the safety valve is greatly influenced by the ambient temperature, the precision of the take-off set value is poor, and the error reaches +/-3 percent. The valve core and the valve seat are pressed together for a long time, and can be adhered due to physical phenomena such as diffusion and the like to cause fixed value drift.
4) The single valve has limited discharge capacity, 1 spring type safety valve cannot meet the requirement of overpressure protection discharge capacity of 1 steam generator, for one main steam pipeline of a nuclear power station, under the condition that constant value grouping is considered and rated system safety discharge capacity is required to be achieved, generally 6-7 spring type safety valves are required to be installed, the system arrangement space is large, the number of devices is large, and large maintenance and verification workload is introduced.
5) On-line verification needs to be carried out in a specific time window after the unit is disconnected from a power grid or before the unit is connected to the power grid, so that the critical path time of unit refueling and overhaul is influenced, and higher industrial safety risks are introduced.
6) The large-displacement spring-loaded safety valve has the disadvantages of poor anti-seismic performance and high anti-seismic design difficulty due to the huge spring volume.
Therefore, the novel safety valve which can meet the overpressure protection requirements of the steam generator and the main steam pipeline of the nuclear power station of a million kilowatt level or above and can effectively solve the defects of the spring-loaded safety valve, is small in discharge capacity, improves the reliability of operation under the working condition of complex media (water hammer caused by water contained in steam), reduces the maintenance workload and risk, and simplifies the system design is developed, and the novel safety valve has important significance for improving the nuclear safety and the industrial safety.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a nuclear power plant is with medium self-driven formula main steam relief valve effectively solves the limited problem of spring relief valve discharge capacity, improves its reliability of operation under operating conditions such as complicated medium and reduces maintenance work load and risk.
The technical scheme of the utility model as follows: a medium self-driven main steam safety valve for a nuclear power plant comprises a main valve, a pilot valve group and a pilot valve, wherein the main valve is connected with the pilot valve group and the pilot valve respectively.
The main valve comprises a valve cover, the valve cover is connected with the valve body through a fastening piece and sealed by a sealing gasket, the valve core is arranged in the valve body, the valve core is provided with a rod-shaped part, a middle bulge part and a head part, a flow channel is arranged in the valve core, and the piston cylinder is sleeved outside the middle bulge part of the valve core and provides guide for the movement of the valve core; the guide sleeve is arranged on the rod-shaped part of the valve core and provides guide for the movement of the valve core, the preloading spring is arranged on the valve core, the first piston ring is arranged on the piston cylinder, the second piston ring is arranged on the valve core, and the throttling hole is arranged on the valve core.
The fastener is a bolt and a nut.
And a valve position indicating device is arranged on the valve core.
The number of the first piston rings is 1 or more.
The number of the second piston rings is 1 or more.
The pilot valve group comprises a pilot safety valve and an isolation valve.
The pilot valve group is directly arranged on the valve body or is connected with the valve body through a guide pipe.
The pilot safety valve is of a three-way structure and is provided with two medium inlets, the opening of the main valve is driven by the opening of the pilot safety valve to discharge the medium, and the closing of the main valve is realized by the closing of the pilot safety valve.
The pilot valve is directly arranged on the valve body or is connected with the valve body through a guide pipe.
The beneficial effects of the utility model reside in that:
1) The utility model has time difference between the action of the pilot valve and the action of the main valve, which can prevent the main valve from frequently acting under the transient states of phase change, system pressure transient and the like of the medium, avoid the fault mode that the water hammer can not return to the seat, and effectively improve the reliability of the safety valve in the operation of complex medium working condition;
2) The aperture of the pilot valve is far smaller than that of the main valve and is also far smaller than that of the spring type main steam safety valve, the reliability, the sensitivity and the control precision of the pilot valve are improved, the fixed value is accurate, and the error is small;
3) The discharge capacity requirement of large discharge capacity can be met, and the discharge capacity requirement of overpressure protection of 1 steam generator and a main steam pipeline can be met by the discharge capacity of 1 medium self-driven safety valve;
4) The reliability of the main valve in action under different medium working conditions can be improved by adjusting the through passage of the throttling hole;
5) The main valve is driven by medium pressure difference, and can realize good sealing when the system pressure is close to the setting value of the safety valve, thereby solving the problem of front leakage of the spring type main steam safety valve;
6) Active redundant drive is provided, and the opening reliability of the safety valve is further improved;
7) The number of the main steam safety valves is greatly reduced, and the maintenance is mainly performed by the check and the maintenance of the pilot valve with a small diameter, so that the maintenance workload of the main steam safety valves is greatly reduced;
8) The verification of the pilot valve can adopt off-line verification, and nuclear safety risks and industrial safety risks existing in the on-line verification process of the spring type main steam safety valve are eliminated;
9) The online calibration function of the pilot valve is reserved, and selection is provided for different test requirements;
10 The valve core acts to provide damping to prevent impact damage during the opening process of the safety valve.
Drawings
Fig. 1 is a schematic structural view of a medium self-driven main steam safety valve for a nuclear power plant provided by the present invention;
FIG. 2 is an enlarged view of a portion I of FIG. 1;
FIG. 3 is an enlarged view of a portion II of FIG. 1;
fig. 4 is a partially enlarged view of a portion iii in fig. 1.
In the figure: 1 valve cover, 2 bolts, 3 nuts, 4 sealing gaskets, 5 valve bodies, 6 piston cylinders, 7 first piston rings, 8 guide rings, 9 second piston rings, 10 valve cores, 11 preloading springs, 121 pilot safety valves, 122 isolation valves, 13 pilot valves and 14 throttling holes.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1, a medium self-driven main steam safety valve for a nuclear power plant comprises a main valve, a pilot valve group 12 and a pilot valve 13, wherein the main valve is respectively connected with the pilot valve group 12 and the pilot valve 13.
The main valve comprises a valve cover 1, a bolt 2, a nut 3, a sealing gasket 4, a valve body 5, a piston cylinder 6, a first piston ring 7, a guide 8, a second piston ring 9, a valve core 10, a preload spring 11 and a throttling hole 14.
The valve cover 1 is connected with the valve body 5 through a fastener (a bolt 2 and a nut 3), sealing is realized by adopting a sealing gasket 4, the valve core 10 is arranged in the valve body 5, the valve core 10 is provided with a rod-shaped part, a middle bulge part and a head part, a flow passage is arranged in the valve core 10 to realize discharge and sealing of a medium, and a valve position indicating device can be arranged on the valve core 10; the piston cylinder 6 is sleeved outside the middle convex part of the valve core 10 and provides guidance for the movement of the valve core 10; the guide 8 is sleeved on the rod-shaped part of the valve core and provides a guide for the movement of the valve core 10, and a flow passage for connection is arranged; a preload spring 11 is installed on the valve core 10 to provide a closing force and a sealing force to the valve core 10; as shown in fig. 2, the first piston ring 7 is mounted on the piston cylinder 6, and the number of the first piston ring 7 can be 1 or more, and is used for realizing sealing between the piston cylinder 6 and the valve body 5; as shown in fig. 3, the second piston ring 9 is mounted on the valve core 10, and there may be 1 or more second piston rings 9 for sealing between the piston cylinders 6 of the valve core 10; as shown in fig. 3, the orifice 14 is provided in the valve body 10, and the orifice 14 is detachable and changeable in flow diameter for adjusting the operating performance of the main valve.
As shown in figure 1, a valve cover 1, a valve body 5, a piston cylinder 6 and a valve core 10 of the medium self-driven safety valve for the nuclear power plant divide a cavity of the safety valve into 4 partial areas A, B, C and D. The area A is a medium inlet of the safety valve, the medium in the area A enters the area B through the throttling hole 14 on the valve core 10 and enters the area C through the flow channel on the valve core 10, the medium in the area B can also enter the area C through the gap between the guide 8 and the valve core 10, and the area D is communicated with the atmosphere.
The pilot valve group 12 includes a pilot relief valve 121 and an isolation valve 122. Pilot valve group 12 is directly mounted on the upper part of the outer side of valve body 5, and the medium in area a and area C is introduced into pilot valve group 12, or can be conducted to area a and area C through a conduit.
The pilot safety valve 121 has a three-way structure and two medium inlets, and the opening of the main valve is driven by the opening of the pilot safety valve 121 to discharge the medium and the closing of the main valve is realized by the closing of the pilot safety valve 121.
The opening and closing of the isolation valve 122 respectively realize the communication and isolation of the pilot safety valve 121 and the upper chamber of the main valve, and when the isolation valve 122 is closed, the opening of the pilot safety valve 121 does not cause the opening of the main valve, so that the online verification of the pilot safety valve 121 is realized.
The pilot valve 13 is an actively driven pilot valve, the main valve is driven by opening the discharge medium of the pilot valve 13, and the power is preferably electromagnetic driven, and can also be driven by electric power, pneumatic power and the like. The pilot valve 13 is directly mounted on the upper part of the outer side of the valve body 5, and the medium in the area C is introduced into the pilot valve group 13 or can be conducted with the area C through a conduit.
The main functions of the medium self-driven safety valve for the nuclear power plant are realized as follows:
a valve cover 1, a valve body 5, a piston cylinder 6 and a valve core 10 of a medium self-driven safety valve for a nuclear power plant divide a cavity of the safety valve into 4 parts, namely an area A, an area B, an area C and an area D. The area A is a medium inlet of the safety valve, the medium in the area A enters the area B through the throttling hole 14 and enters the area C through a flow passage on the valve core 10, the medium in the area B can also enter the area C through a gap between the components, and the area D is communicated with the atmosphere.
The closing and sealing of the medium self-driven main steam safety valve for the nuclear power plant are as follows:
a pilot valve group 12 and a pilot valve 13 of a medium self-driven safety valve for a nuclear power plant are in a closed state, and a valve core 10 is closed under the action force of the dead weight and the spring force of the valve core 10 and the medium of an area A, an area B and an area C on the valve core 10.
A medium self-driven safety valve for a nuclear power plant is in a closed state under the normal operation working condition, and the pressure of an area A, the pressure of an area B and the pressure of an area C are the same. Because the sum of the medium acting areas of the area A, the area B and the area C on the valve core 10 is larger than the medium acting area of the area D, and the pressure of the area A, the area B and the area C is larger than the pressure of the area D, the reliable sealing of the safety valve is realized.
A nuclear power plant is with passive opening of medium self-driven owner steam relief valve as follows:
a medium of a region A of a medium self-driven safety valve for a nuclear power plant enters an inlet 1 of a pilot safety valve 121 under the operation working condition; the isolation valve 12B is in an open state and the medium of zone C enters the inlet 2 of the pilot relief valve 121 through the isolation valve 122.
When the system pressure (zone a, zone B, zone C) reaches the setting value of the pilot relief valve 121, the pilot relief valve 121 opens, closes the pilot relief valve 121 at the inlet of the zone a, and discharges the medium of the zone B. Since the discharge area of the pilot relief valve 121 is larger than the sum of the upper flow passage area of the spool 10 and the flow area of the orifice 14, the pressures of the regions B and C are decreased; when the medium acting force of the medium in the area A on the valve core 10 is larger than the sum of the medium pressure acting force of the medium in the area B and the area C on the valve core 10, the dead weight of the valve core 10 and the acting force of the spring 11, the valve core 10 moves upwards to open the main valve (the opening time can be less than 1 s), and the system medium (the area A) enters the area D and is exhausted to the atmosphere, so that the pressure relief function is realized.
When the valve core 10 moves upwards, the area of the medium flowing from the area B to the area C is closed; meanwhile, the rapid upward movement of the valve core 10 compresses the medium in the area C to increase the pressure in the area C, so that resistance is formed on the upward movement of the valve core 10, and the safety valve is prevented from being damaged by impact in the opening process.
A nuclear power plant is with initiative of medium self-driven owner steam relief valve can open as follows:
and opening the pilot valve 13, and similarly realizing the pressure relief of the area B and the area C, thereby realizing the opening of the medium self-driven safety valve for the nuclear power plant.
It is not right above that the utility model discloses do any restriction, all according to the utility model discloses the adaptability that the technique essence goes on is modified, all still belongs to the utility model discloses a scope.
Claims (10)
1. The utility model provides a nuclear power plant is with medium self-driven owner steam relief valve which characterized in that: the pilot valve comprises a main valve, a pilot valve group and a pilot valve, wherein the main valve is respectively connected with the pilot valve group and the pilot valve.
2. The nuclear power plant medium self-driven main steam safety valve as claimed in claim 1, characterized in that: the main valve comprises a valve cover, the valve cover is connected with the valve body through a fastening piece and sealed by a sealing gasket, the valve core is arranged in the valve body, the valve core is provided with a rod-shaped part, a middle bulge part and a head part, a flow channel is arranged in the valve core, and the piston cylinder is sleeved outside the middle bulge part of the valve core and provides guide for the movement of the valve core; the guide sleeve is arranged on the rod-shaped part of the valve core and provides guide for the movement of the valve core, the preloading spring is arranged on the valve core, the first piston ring is arranged on the piston cylinder, the second piston ring is arranged on the valve core, and the throttling hole is arranged on the valve core.
3. The nuclear power plant medium self-driven main steam safety valve as claimed in claim 2, characterized in that: the fastener is a bolt and a nut.
4. The nuclear power plant medium self-driven main steam safety valve of claim 2, characterized in that: and a valve position indicating device is arranged on the valve core.
5. The nuclear power plant medium self-driven main steam safety valve as claimed in claim 2, characterized in that: the number of the first piston rings is 1 or more.
6. The nuclear power plant medium self-driven main steam safety valve as claimed in claim 2, characterized in that: the number of the second piston rings is 1 or more.
7. The nuclear power plant medium self-driven main steam safety valve as claimed in claim 1, characterized in that: the pilot valve group comprises a pilot safety valve and an isolation valve.
8. The nuclear power plant medium self-driven main steam safety valve of claim 1, characterized in that: the pilot valve group is directly arranged on the valve body or is connected with the valve body through a guide pipe.
9. The nuclear power plant medium self-driven main steam safety valve as claimed in claim 7, wherein: the pilot safety valve is of a three-way structure and is provided with two medium inlets, the opening of the main valve is driven by the opening of the pilot safety valve to discharge the medium, and the closing of the main valve is realized by the closing of the pilot safety valve.
10. The nuclear power plant medium self-driven main steam safety valve of claim 1, characterized in that: the pilot valve is directly arranged on the valve body or is connected with the valve body through a guide pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220942351.4U CN218094466U (en) | 2022-04-22 | 2022-04-22 | Medium self-driven main steam safety valve for nuclear power plant |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220942351.4U CN218094466U (en) | 2022-04-22 | 2022-04-22 | Medium self-driven main steam safety valve for nuclear power plant |
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| Publication Number | Publication Date |
|---|---|
| CN218094466U true CN218094466U (en) | 2022-12-20 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202220942351.4U Active CN218094466U (en) | 2022-04-22 | 2022-04-22 | Medium self-driven main steam safety valve for nuclear power plant |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN218094466U (en) |
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2022
- 2022-04-22 CN CN202220942351.4U patent/CN218094466U/en active Active
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