Guide valve of valve adjusting positioner of steam-driven auxiliary feed pump

Abstract

The invention provides a pilot valve of a valve adjusting positioner of a steam-driven auxiliary water feeding pump. The pilot valve of the valve adjusting positioner of the steam-driven auxiliary water feeding pump comprises a valve sleeve, a valve element, an ejector pin, a spring and a valve deck. The valve sleeve is used for being connected with the positioner and serves as an internally-formed air cylinder to achieve the air inlet and exhaust effects. The valve element is installed in the valve sleeve, the plane end of the valve element makes contact with the plug end of the valve sleeve through the spring, the ejector pin is installed below the valve element, and the round head end of the ejector pin makes contact with the groove end of the valve element. The valve cover is connected to the side, away from the valve element, of the plug end of the valve sleeve. During working, the ejector pin acts to drive the pilot valve element to act, the two ends of the valve element receive force of the ejector pin and the spring respectively, and displacement between the valve element and the valve sleeve is controlled. According to the pilot valve, on the basis of an original pilot valve, the plane where the ejector pin makes contact with the valve element is changed into the round head end from the sharp head end, so that the problem that an existing steam-driven auxiliary water feeding pump is poor in rotating speed stability is solved.

Description

Technical Field

[0001] The present application belongs to the technical field of positioner pilot valves, and in particular relates to a steam-driven auxiliary water supply pump regulating valve positioner pilot valve. Background Art

[0002] The auxiliary feedwater system in a nuclear power plant serves as a backup for the normal feedwater system. When the main feedwater system is lost, it provides water to the secondary side of the steam generator. The steam-driven auxiliary feedwater pump, referred to as the steam-assisted pump, is one of the important dedicated safety facilities of the Hualong One unit and an important nuclear safety barrier to ensure the safe and stable operation of the nuclear power unit.

[0003] However, existing steam-driven auxiliary feedwater pumps, such as the Shanghai Apollo steam-driven auxiliary feedwater pump, have the problem of large speed fluctuations, which makes the speed stability of the steam-driven auxiliary feedwater pump poor, and may even cause the main line planning and testing of the nuclear power unit to be hindered, causing a great impact on the progress of the project. Summary of the invention

[0004] In view of this, an embodiment of the present application is dedicated to providing a pilot valve for a pneumatic-assisted water supply pump valve positioner. On the basis of the original pilot valve, the plane where the ejector pin contacts the valve core is modified from a pointed end to a round end to solve the problem of poor speed stability of the existing pneumatic-assisted water supply pump.

[0005] The present application provides a pilot valve for a pneumatic-assisted water supply pump regulating valve positioner, which includes a valve sleeve, a valve core, a ejector pin, a spring and a valve cover. The valve sleeve is used to connect with the positioner, and acts as an internally formed cylinder to perform air intake and exhaust. The valve core is installed in the valve sleeve, and the flat end of the valve core contacts the plug end of the valve sleeve through a spring. The ejector pin is installed below the valve core, and the round end of the ejector pin contacts the groove end of the valve core. The valve cover is connected to the side of the plug end of the valve sleeve away from the valve core. During operation, the action of the ejector pin drives the action of the pilot valve core, and the two ends of the valve core receive the force of the ejector pin and the spring respectively to control the displacement between the valve core and the valve sleeve.

[0006] In a specific embodiment of the present application, the surface of the valve core is plated with hard chrome.

[0007] In a specific embodiment of the present application, the valve core has a variety of sizes to adapt to different pneumatic auxiliary water supply pumps.

[0008] In a specific embodiment of the present application, a stepped platform is reserved at the lowest position inside the valve sleeve, and the stepped platform is used to place the ejector pin.

[0009] In a specific embodiment of the present application, the ejector pin is connected to the lowest groove of the valve core in the form of metal surface to metal surface. The lowest part of the ejector pin is used to be directly placed on the positioner diaphragm, and the change in the position of the diaphragm is driven by the change in the positioner feedback spring, thereby indirectly driving the change in the position of the ejector pin.

[0010] In a specific embodiment of the present application, the valve core serves as an important control component of the internal sliding valve. The valve core position is pushed by the change of the ejector pin position, thereby changing the intake and exhaust volumes of the internal cylinder to achieve overall control of the regulating gas path.

[0011] In a specific embodiment of the present application, the spring is directly placed on the uppermost plane of the valve core. When the movement of the valve core changes, the spring is used to adjust the position of the buffer valve core through the change of compression amount.

[0012] In a specific embodiment of the present application, the valve cover is connected to the valve sleeve, and the exhaust gas discharged from the internal cylinder due to insufficient sealing is discharged through the circular hole on the valve cover.

[0013] In a specific embodiment of the present application, the valve sleeve is fixedly connected to the positioner via an external thread, and the valve cover is connected to the valve sleeve via an external thread.

[0014] In a specific embodiment of the present application, the valve sleeve fixes the rubber sealing ring through three sealing ring grooves.

[0015] The beneficial effects of the technical solution of the present application are: by optimizing the plane where the ejector pin contacts the valve core from a pointed end to a round end, and optimizing the bottom of the ejector pin from an inverted cone to a hemispherical shape on the basis of the original pilot valve, the problem of the valve core and the ejector pin being stuck due to the tilt of the ejector pin during the operation process is reduced, and the stability of the pilot valve of the valve positioner of the pneumatic-assisted water supply pump is improved; by adjusting the size of the valve core outer diameter, the gap between the valve core and the inner wall of the valve sleeve is reduced, and the smoothness of the action of the pilot valve of the valve positioner of the pneumatic-assisted water supply pump is improved, thereby reducing the speed fluctuation amplitude and improving the speed stability of the pneumatic-assisted water supply pump. The present invention is developed based on the domestic pneumatic-assisted pump pneumatic control equipment, and creatively optimizes the original pilot valve structure. It has been applied on site, and the speed fluctuation of the domestic pneumatic-assisted pump is significantly reduced. The embodiments of the present application greatly shorten the time for hot testing of overhaul steam-assisted pumps and save overhaul man-hours. Taking the Hualong One unit as an example, after using the steam-driven auxiliary feedwater pump regulating valve positioner pilot valve provided by the embodiments of the present application, from 2020 to the present, during the hot test of Unit 6, and during the daily and overhaul of Units 5 and 6, the steam-assisted pump related tests were all successful at one time, and the speed error was small, which has entered the forefront of the industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Shown is a cross-sectional schematic diagram of a pilot valve of a pneumatic auxiliary water supply pump valve positioner provided in one embodiment of the present application.

[0017] Figure 2 Shown Figure 1 The figure shows a three-dimensional structural schematic diagram of a valve sleeve in a pilot valve of a pneumatic auxiliary water supply pump valve positioner.

[0018] Figure 3 Shown Figure 2 A schematic front view of the valve sleeve is shown.

[0019] Figure 4 Shown Figure 2 A schematic cross-sectional view of the valve sleeve is shown.

[0020] Figure 5 Shown Figure 2 A schematic rear view of the valve sleeve is shown.

[0021] Figure 6 Shown Figure 1 The figure shows a three-dimensional structural diagram of a valve core in a pilot valve of a pneumatic auxiliary water supply pump regulating valve positioner.

[0022] Figure 7 Shown Figure 6 Schematic diagram of the front view of the valve core shown.

[0023] Figure 8 Shown Figure 6 A schematic cross-sectional view of the valve core is shown.

[0024] Fig. 9 Shown Figure 6 A schematic side view of the valve core is shown.

[0025] Fig.10 Shown Figure 1 The figure shows a schematic diagram of the three-dimensional structure of a ejector pin in a pilot valve of a pneumatic auxiliary water supply pump valve positioner.

[0026] Fig.11 Shown Fig.10 A schematic front view of the ejector pin is shown. DETAILED DESCRIPTION

[0027] From February 18 to March 1, 2020, Unit 5 of the Fuqing Nuclear Power Plant was in the hot test phase. During the commissioning phase, the Shanghai Apollo steam-driven auxiliary feedwater pump was tested. The speed fluctuations of 5TFA003PO and 5TFA004PO exceeded the acceptance criteria during operation, resulting in test failure, which hindered the main line plan and test of the unit and had a great impact on the progress of the project. This defect was identified as a "top ten defects" concern project of the company.

[0028] After continuous tests and discussions, it was found that the H-6200 model positioner pilot valve in the pneumatic control system had problems such as poor manufacturing process, low processing accuracy, and defects in functional principles, which made the positioner pilot valve of the steam-assisted pump regulating valve fail to meet the stable operation requirements, thus causing the above defects.

[0029] In order to solve at least one of the above problems, the embodiment of the present application provides a pilot valve of a pneumatic auxiliary water supply pump valve positioner. The technical scheme in the embodiment of the present application will be clearly and completely described below in conjunction with the drawings in the embodiment of the present application. Obviously, the described embodiment is only a part of the embodiment of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] At least one embodiment of the present application provides a pilot valve for a pneumatic auxiliary water supply pump valve positioner, referring to Figures 1 to 11 The pilot valve of the pneumatic auxiliary water supply pump regulating valve positioner includes a valve sleeve 1, a valve core 2, a ejector pin 3, a spring 4 and a valve cover 5. The valve sleeve 1 is used to connect with the positioner and acts as an internally formed cylinder to perform air intake and exhaust. The valve core 2 is installed in the valve sleeve 1, and the flat end of the valve core 2 contacts the plug end of the valve sleeve 1 through the spring 4. The ejector pin 3 is installed below the valve core 2, and the round end of the ejector pin 3 contacts the groove end of the valve core 2. The valve cover 5 is connected to the side of the plug end of the valve sleeve 1 away from the valve core 2. During operation, the action of the ejector pin 3 drives the action of the pilot valve core 2, and the two ends of the valve core 2 receive the force of the ejector pin 3 and the spring 4 respectively to control the displacement between the valve core 2 and the valve sleeve 1.

[0031] It should be noted that the pilot valve of the steam-driven auxiliary water supply pump regulating valve positioner is installed inside the positioner to control the air source entering the valve diaphragm. The positioner can be the H-6200 model positioner of Shanghai Automatic Instrument Factory No. 7. The steam-driven auxiliary water supply pump can be referred to as a steam-assisted pump.

[0032] The specific implementation method is: the feedback cam below the positioner receives the control air pressure output by the electrical converter, the feedback cam moves according to the control air pressure, and drives the ejector pin 3 to move through the spring device below the positioner, and the movement of the ejector pin 3 drives the pilot valve core 2 to move, and the two ends of the valve core 2 receive the force of the ejector pin 3 and the spring 4 respectively, controlling the displacement between the valve core 2 and the valve sleeve 1, thereby controlling the air source entering the valve diaphragm, and completing the process of controlling the valve opening with electrical signals.

[0033] According to the technical solution provided in the embodiment of the present application, on the basis of the original pilot valve, the plane where the ejector pin 3 contacts the valve core 2 is optimized from a pointed end to a round end, and the bottom of the ejector pin 3 is optimized from an inverted cone to a hemispherical shape, thereby reducing the problem of the valve core 2 and the ejector pin 3 being stuck due to the ejector pin tilting during the operation process, and improving the stability of the pilot valve of the pneumatic auxiliary water supply pump valve positioner; by adjusting the size of the outer diameter of the valve core 2, reducing the gap between the valve core 2 and the inner wall of the valve sleeve, the smoothness of the action of the pilot valve of the pneumatic auxiliary water supply pump valve positioner is improved, thereby improving the response accuracy of the control system, reducing the speed fluctuation amplitude, and improving the speed stability of the pneumatic auxiliary water supply pump. This application is developed based on the domestic pneumatic auxiliary pump pneumatic control equipment, and creatively optimizes the original pilot valve structure. It has been applied on site, and the speed fluctuation of the domestic pneumatic auxiliary pump has been significantly reduced. The embodiments of the present application greatly shorten the time of hot state test of overhaul steam-assisted pump and save overhaul man-hours. Taking the Hualong One unit as an example, after using the steam-driven auxiliary feedwater pump regulating valve positioner pilot valve provided by the embodiments of the present application, during the hot test of Unit 6, 501 overhaul, 601 overhaul and 502 overhaul, the steam-assisted pump related tests were all successful at one time, and the speed error was small, which has reached the forefront level in the same industry.

[0034] In at least one embodiment of the present application, the surface of the valve core 2 is plated with hard chrome, so as to improve the wear resistance of the valve core and reduce wear when the steam-assisted pump regulating valve is in operation.

[0035] The original pilot valve's control accuracy and sensitivity of the regulating valve are far from meeting the requirements for the stable operation of the steam-assisted pump. The pilot valve of the steam-assisted feedwater pump regulating valve positioner provided in the embodiment of the present application is optimized from a pointed head to a round head through the ejector pin 3, and the bottom of the ejector pin 3 is optimized from an inverted cone to a hemispherical form. The surface of the valve core 2 is hard chrome plated and the outer diameter size is adjusted to improve the control accuracy and sensitivity of the pilot valve to the regulating valve. The pilot valve of the steam-assisted feedwater pump regulating valve positioner has been used in 4 units of this power plant and 3 nuclear power plants in the same industry, and can perfectly adapt to the domestic steam-assisted pump control system. The new pilot valve was used on-site in the nuclear power plant to test the steam-assisted pump, and the speed error was far less than the ±80rpm required by the test.

[0036] In at least one embodiment of the present application, the valve core 2 has a variety of sizes to adapt to different steam-assisted water supply pumps. In this way, the outer diameter of the corresponding valve core 2 can be adjusted according to the characteristics of each steam-assisted pump to achieve perfect adaptation to the requirements of stable operation of different steam-assisted pumps.

[0037] For example, adaptive optimization can be carried out based on the characteristics of the Hualong No. 1 steam-assisted pump to perfectly match the action requirements of the Fuqing Hualong No. 1 steam-assisted pump.

[0038] In at least one embodiment of the present application, a stepped platform is reserved at the lowest position inside the valve sleeve 1 , and the stepped platform is used to place the ejector pin 3 .

[0039] In at least one embodiment of the present application, the ejector pin 3 is connected to the lowermost groove of the valve core 2 in the form of metal surface to metal surface. The lowermost part of the ejector pin 3 is used to be directly placed on the positioner diaphragm, and the change in the position of the diaphragm is driven by the change in the positioner feedback spring, thereby indirectly driving the change in the position of the ejector pin 3.

[0040] In at least one embodiment of the present application, the valve core 2 is an important control component of the internal sliding valve. The position of the valve core 2 is pushed by the change of the position of the ejector pin 3, thereby changing the intake and exhaust volumes of the internal cylinder to achieve overall control of the regulating gas path.

[0041] In at least one embodiment of the present application, the spring 4 is directly placed on the uppermost plane of the valve core 2. When the valve core 2 changes its movement, the spring 4 is used to adjust and buffer the position of the valve core 2 by changing the compression amount.

[0042] In at least one embodiment of the present application, the valve cover 5 is connected to the valve sleeve 1 , and the exhaust gas discharged from the internal cylinder due to insufficient sealing is discharged through the circular hole on the valve cover 5 .

[0043] In at least one embodiment of the present application, the valve sleeve 1 is fixedly connected to the positioner via an external thread. The valve cover 5 is connected to the valve sleeve 1 via an external thread.

[0044] In at least one embodiment of the present application, the valve sleeve 1 fixes the rubber sealing ring through three sealing ring grooves, so that the sealing performance of the internal sliding valve cylinder can be improved.

[0045] In at least one embodiment of the present application, the plug end of the valve sleeve 1 is a hexagonal fastening plug end.

[0046] It should be noted that the combination of the various technical features in the embodiments of the present application is not limited to the combination described in the embodiments of the present application or the combination described in the specific embodiments, and all technical features described in the present application can be freely combined or combined in any way unless there is a contradiction between them.

[0047] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A pilot valve for a steam-driven auxiliary water pump valve positioner, characterized in that: Including valve sleeve, valve core, ejector pin, spring and valve cover, The valve sleeve is used to connect with the positioner and acts as an internally formed cylinder for air intake and exhaust. The valve core is installed in the valve sleeve, and the flat end of the valve core contacts the plug end of the valve sleeve through a spring. The ejector pin is installed below the valve core, and the round end of the ejector pin contacts the groove end of the valve core. The valve cover is connected to the side of the plug end of the valve sleeve away from the valve core. During operation, the action of the ejector pin drives the pilot valve core to move. The two ends of the valve core receive the force of the ejector pin and the spring respectively, controlling the displacement between the valve core and the valve sleeve.

2. The pilot valve of the pneumatic auxiliary water supply pump valve positioner according to claim 1 is characterized in that: The surface of the valve core is plated with hard chrome.

3. The pilot valve of the pneumatic auxiliary water supply pump valve positioner according to claim 1, characterized in that: The valve core has various sizes to adapt to different steam-driven auxiliary water pumps.

4. The pilot valve of the pneumatic auxiliary water supply pump valve positioner according to claim 1, characterized in that: A stepped platform is reserved at the lowest position inside the valve sleeve, and the stepped platform is used to place the ejector pin.

5. The pilot valve of the pneumatic auxiliary water supply pump valve positioner according to claim 1, characterized in that: The ejector pin is connected to the bottom groove of the valve core in the form of metal surface to metal surface. The bottom part of the ejector pin is used to be directly placed on the positioner diaphragm. The change of the positioner feedback spring drives the change of the diaphragm position, which indirectly drives the change of the ejector pin position.

6. The pilot valve of the pneumatic auxiliary water supply pump valve positioner according to claim 1, characterized in that: As an important control component of the internal slide valve, the valve core pushes the valve core position by changing the position of the ejector pin, thereby changing the intake and exhaust volume of the internal cylinder to achieve overall control of the regulating gas path.

7. The pilot valve of the pneumatic auxiliary water supply pump valve positioner according to claim 1, characterized in that: The spring is placed directly on the uppermost plane of the valve core. When the valve core moves, the spring is used to adjust and buffer the position of the valve core through changes in compression.

8. The pilot valve of the pneumatic auxiliary water supply pump valve positioner according to claim 1, characterized in that: The valve cover is connected to the valve sleeve, and the exhaust gas discharged from the internal cylinder due to insufficient sealing is discharged through the circular hole on the valve cover.

9. The pilot valve of the pneumatic auxiliary water supply pump valve positioner according to claim 1, characterized in that: The valve sleeve is fixedly connected to the positioner through external threads, and the valve cover is connected to the valve sleeve in the form of external threads.

10. The pilot valve of the pneumatic auxiliary water supply pump valve positioner according to any one of claims 1 to 9, characterized in that: The valve sleeve fixes the rubber sealing ring through 3 sealing ring grooves.

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