Valve position indicating device and pilot operated safety valve with same

Abstract

The invention relates to the technical field of nuclear power valves, and discloses a valve position indicating device and a pilot operated safety valve. The pilot operated safety valve comprises a main valve and a pilot operated electromagnetic valve, the main valve comprises a main valve body, the main valve body is provided with a main valve core, and the main valve core is connected with a valve position indicating device; the valve position indicating device comprises a mounting shell, the mounting shell is provided with an indicating piece and a sensing piece, the indicating piece penetrates through the main valve body in a sliding mode and is connected with the main valve element, and the far end of the indicating piece triggers the sensing piece in the sliding motion process to display the position of the main valve element. The indicating piece extends in the movement direction of the valve element to be of a multi-section structure. On the basis, heat is further dissipated and cooled through the heat dissipation fins of the mounting shell, and the main valve body and the mounting shell form end face sealing fit, so that the valve position indicating device is not influenced by high-temperature and high-pressure working conditions, a stable and reliable valve position indicating function is provided, and the overall working stability and reliability of the pilot operated safety valve are improved.

Description

Technical Field

[0001] The present application relates to the technical field of nuclear power valves, and in particular to a valve position indicating device and a pilot safety valve having the valve position indicating device. Background Art

[0002] A nuclear power plant usually consists of a primary circuit and a secondary circuit, and the two circuits work together to realize the power generation function of the nuclear power plant.

[0003] The primary loop is also called the reactor coolant loop. In this loop, the reactor releases a large amount of heat energy, which is used to heat the coolant in the primary loop. The high-temperature and high-pressure coolant then enters the steam generator (hereinafter referred to as SG), and transfers heat to the water in the secondary loop through the heat transfer tube of the SG in a heat exchange manner, turning it into steam.

[0004] The secondary circuit is also called the steam circuit. In this circuit, the steam generated enters the steam turbine, drives the turbine to operate, and then drives the generator to generate electricity, converting the heat energy of the steam into electrical energy. After the steam does work in the steam turbine, it enters the condenser to cool into water, and then is transported back to the steam generator for recycling.

[0005] The reactor pressure vessel and the heat transfer tubes in the SG form a primary circuit, and the main steam pipeline of the SG passes through the containment penetration to the outside of the containment and forms a secondary circuit with the steam turbine, condenser, etc. A main steam isolation valve is installed on the main steam pipeline of the SG, and the safety valve is installed on the pipeline between the SG and the main steam isolation valve. Its main function is to discharge part of the steam through the safety valve when the pressure of the steam generator and the pipeline between the steam generator and the main steam isolation valve reaches the specified limit, so as to prevent the pressure of the related equipment of the secondary circuit from exceeding the specified limit, ensure the safe operation of the reactor and ensure the integrity of the pressure boundary of the secondary circuit.

[0006] The safety valve is one of the key components of the secondary circuit of a nuclear power unit. It is located in a high-temperature, high-pressure environment. The high pressure can reach more than ten megapascals, and the high temperature can reach hundreds of degrees Celsius. The safety valve usually needs to be equipped with a valve position indicator to indicate the valve core opening position, but the valve position indicator is easily affected by the working environment. How to maintain the working stability and reliability of the valve position indicator under the influence of the high-temperature, high-pressure working environment of the safety valve is very important for the safe operation of the safety valve used in nuclear power units. Summary of the invention

[0007] In order to maintain the working stability and reliability of the valve position indicator under the high temperature and high pressure working environment of the safety valve, the present application provides a valve position indicating device and a pilot safety valve having the valve position indicating device.

[0008] In the first aspect, the present application provides a valve position indicating device, which adopts the following technical solution: A valve position indicating device comprises a mounting shell, wherein the mounting shell is provided with an indicating member and a sensing member used in conjunction with each other, wherein the indicating member is used to slide through the valve body and is connected to the valve core to move synchronously with the valve core, and the distal end of the indicating member triggers the sensing member during the sliding movement to display the position of the valve core; the indicating member is extended along the movement direction of the valve core to form a multi-section structure, wherein the indicating member comprises a plurality of indicating rods, and adjacent indicating rods are detachably connected with adapter sleeves; the mounting shell is provided with heat dissipating fins, and the mounting shell is also used to be sealed and connected to the valve body.

[0009] By adopting the above technical solution, the indicator adopts a multi-stage structure design, which can not only meet the structural design requirements of the indicator with a longer overall length, maintain structural strength and stability, and reduce the difficulty of processing and manufacturing and later maintenance, but also can block the heat on one side of the valve from quickly transmitting to the sensing part at the far end of the indicator to a certain extent, and can also be used as the valve stem of the valve, which has good practicality. On this basis, the heat dissipation fins arranged on the mounting shell are used to dissipate heat and cool down, and at the same time, the sealing of the mounting shell and the valve body is matched to maintain good sealing, so that the valve position indicating device arranged on the safety valve will not be affected by high temperature and high pressure conditions, and can still provide a stable and reliable valve position indication function.

[0010] Preferably, the mounting shell includes a first shell, a second shell and a third shell which are connected in sequence along the movement direction of the indicator member, the first shell is used for sealing connection with the valve body, the first shell is provided with a first heat dissipation fin, the sensing member is arranged on the third shell, and the indicator rod slides through the first shell, the second shell and the third shell.

[0011] By adopting the above technical solution and a combined structure installation shell design, the second shell can prevent the heat from the first shell from being quickly transferred to the third shell, thereby avoiding the failure of the sensor due to direct exposure to a high temperature environment.

[0012] Preferably, a heat dissipation cavity is formed in the second shell, and second heat dissipation fins are further arranged outside the second shell.

[0013] By adopting the above technical solution, the heat dissipation cavity and the second heat dissipation fins are used in combination to achieve the purpose of further heat dissipation at the second shell body, thereby further improving the heat insulation and heat dissipation effect of the mounting shell.

[0014] Preferably, a sliding fit clearance formed between the third housing and the indicator rod slidably penetrating the third housing is smaller than a sliding fit clearance formed between the indicator rod and the corresponding first housing and the second housing.

[0015] By adopting the above technical solution, the sliding fit clearance between the indicator rod and the third shell is reduced to limit the heat from being directly conducted to the induction element located at the third shell through the sliding fit clearance between the indicator rod and the first shell and the second shell, thereby further protecting the induction element.

[0016] Preferably, the indicator rod is rotationally matched with the first shell, the second shell and the third shell, and the indicator rod that slides through the third shell is provided with a trigger member, and the trigger member is arranged as an annular structure. During the sliding movement of the indicator member, the trigger member abuts against and triggers the sensing member to display the position of the valve core.

[0017] By adopting the above technical solution, it can adapt to the rotational movement of the indicator rod caused by the influence of the medium during the operation of the pilot safety valve, and at the same time, a triggering member with an annular structure is adopted to meet the design requirement that the indicator member can also abut against the triggering sensing member after rotation.

[0018] Preferably, the first shell is used for detachable sealing connection with the valve body, the second shell is detachably connected to the first shell, and the third shell is detachably connected to the second shell.

[0019] By adopting the above technical solution, the installation shell is not only a modular structure, but also a detachable structure, which can meet the needs of subsequent inspection and maintenance operations.

[0020] Preferably, the first shell is also provided with a lifting ring structure for lifting; the first shell is penetrated with a connecting stud, and the connecting stud is used for detachable connection with the valve body.

[0021] By adopting the above technical solution, in subsequent inspection and maintenance operations, the first shell can be lifted by the lifting ring structure, and the connecting studs can also play the role of temporarily supporting and limiting the first shell, thereby preventing the weight of the installation shell from directly acting on the indicator rod.

[0022] Preferably, the first shell is further provided with a guide member, and the indicator rod and the guide member form a sliding plug-in fit.

[0023] By adopting the above technical solution, the guide member guides the sliding movement of the indicator rod, improves the stability and reliability of the sliding movement of the indicator rod, thereby achieving the purpose of improving the accuracy of valve position display, while reducing the impact on the opening and closing movement of the valve core.

[0024] Preferably, the first shell is further provided with a stuffing box structure, and the indicator rod slidingly penetrating the first shell and the stuffing box structure form a sliding seal fit.

[0025] By adopting the above technical solution, the stuffing box structure plays a role in sealing the sliding fit gap between the indicator rod and the first housing.

[0026] Preferably, the first shell and / or the second shell is provided with a disc spring structure for compensating for the gap caused by thermal expansion and contraction of the stuffing box structure.

[0027] By adopting the above technical solution, when the stuffing box structure has loose gaps due to thermal expansion and contraction, the disc spring structure can provide compensating force to the stuffing box structure to maintain the sealing effect of the stuffing box structure.

[0028] Preferably, the sensing member is configured as a limit switch, and the limit switch includes a distal limit switch and a proximal limit switch, and the indicator member abuts against and triggers the distal limit switch when the sliding movement is until the valve core is fully opened, and the indicator member abuts against and triggers the proximal limit switch when the sliding movement is until the valve core is closed.

[0029] By adopting the above technical solution, two sets of limit switches located at the far end and the near end of the design stroke of the indicator are used to form a sensing element, which is then combined with the indicator to achieve the design purpose of abutting to trigger and display the valve position.

[0030] In the second aspect, the present application provides a pilot-operated safety valve, which adopts the following technical solution: A pilot-operated safety valve comprises a main valve and a pilot solenoid valve used in conjunction with each other, wherein the main valve comprises a main valve body, a main valve core is arranged in the main valve body, and the main valve core is connected to the valve position indicating device; the indicating member is extended along the movement direction of the main valve core and slidably penetrates the main valve body, a sealing ring is arranged outside the main valve body, and the mounting shell and the main valve body form an end face sealing cooperation through the sealing ring.

[0031] By adopting the above technical scheme, the sealing ring of the main valve body and the mounting shell of the valve position indicating device form an end face seal, so as to further improve the sealing performance of the valve position indicating device when used in conjunction with the main valve of the pilot safety valve, thereby further improving the valve position indication stability and reliability of the pilot safety valve, and further achieving the purpose of improving the overall working stability and reliability of the pilot safety valve.

[0032] Preferably, a middle cavity is formed in the main valve body, and a constant pressure channel and an inlet channel are formed in the middle cavity at the inlet of the main valve, and an outlet channel is formed in the middle cavity at the outlet of the main valve. The middle cavity is also connected to the pilot solenoid valve to form a pressure relief inlet channel, the constant pressure channel is connected to the pressure relief inlet channel and forms a first chamber in the middle cavity, and the inlet channel is connected to the outlet channel and forms a second chamber in the middle cavity; the main valve core is slidably arranged in the middle cavity, and a main valve seat is also arranged in the main valve body; when the pilot solenoid valve is closed, the main valve core and the main valve seat cooperate to close the outlet channel; when the pilot solenoid valve is opened, a pressure difference is formed between the first chamber and the second chamber, the pressure of the main valve core on the second chamber side is greater than the pressure of the main valve core on the first chamber side, and the main valve core is separated from the main valve seat to open the main valve.

[0033] By adopting the above technical solution, the first chamber of the main valve is connected to the pilot solenoid valve to realize a pilot design scheme for rapid pressure relief and precise control of the opening of the main valve core. At the same time, the pressure difference between the first chamber and the second chamber of the main valve is used to achieve the design purpose of opening and closing the main valve.

[0034] Preferably, the pilot solenoid valve is further connected to the outlet channel via a pressure relief return channel; when the pilot solenoid valve is opened, the medium enters the outlet channel via the pressure relief return channel.

[0035] By adopting the above technical solution, the medium discharged when the pilot solenoid valve is opened can enter the outlet channel of the main valve through the pressure relief return channel and be discharged together with the medium discharged when the main valve is opened. This can not only reduce the medium loss, but also realize the integrated design of the pilot solenoid valve and the main valve at the valve outlet position, which is conducive to reducing space occupancy and thus achieving the design purpose of miniaturization of the pilot safety valve.

[0036] Preferably, a guide sleeve is provided in the middle cavity, a piston is slidably provided on the guide sleeve, and the main valve core is connected to the piston.

[0037] By adopting the above technical solution, with the help of the sliding guide cooperation of the guide sleeve and the piston, the purpose of sliding guide of the main valve core is achieved, the stability of the sliding movement of the main valve core is improved, and then the purpose of improving the stability and reliability of the opening and closing actions of the main valve is achieved.

[0038] Preferably, a plurality of drainage holes are opened on the circumferential side of the guide sleeve, and the medium in the first chamber is discharged through the drainage holes and discharged through the pressure relief inlet channel. The drainage holes located at the bottom of the guide sleeve are used to connect the first chamber and the constant pressure channel.

[0039] Preferably, the main valve core is clamped with a valve core seat, and the valve core seat is connected to the piston and forms a sliding fit with the guide sleeve.

[0040] By adopting the above technical solution, the valve core seat not only plays the role of connecting the piston and the main valve core, but also can form a sliding guide with the guide sleeve to further improve the stability of the sliding movement of the main valve core.

[0041] Preferably, the piston is threadedly connected to the valve core seat, and a fastening screw is also penetrated and connected to the piston, and the fastening screw and the valve core seat form an abutting fit.

[0042] By adopting the above technical solution, in subsequent inspection and maintenance operations, the worn piston can be replaced, and the piston and the valve core seat can be further locked by tightening the screws, thereby reducing the risk of abnormal separation of the piston and the valve core seat, and balancing the difficulty of inspection and maintenance with the working stability of the guide structure.

[0043] Preferably, a piston ring is detachably mounted on the circumferential side of the piston, and a sliding fit clearance formed by the piston ring and the guide sleeve is smaller than a sliding fit clearance formed by the piston and the guide sleeve.

[0044] By adopting the above technical solution, the piston ring can effectively control the gap size between the guide sleeve and the piston, reducing the risk of the medium flowing into the second chamber through the inlet channel entering the first chamber in large quantities through the sliding fit gap.

[0045] Preferably, a mounting seat is further provided in the middle cavity, and an elastic member is connected between the mounting seat and the piston, and the elastic member provides a positive force to the main valve core.

[0046] By adopting the above technical solution, the elastic part can drive the main valve core to slide toward the main valve seat, which is beneficial to improving the closing effect of the main valve core and the main valve seat when the main valve is closed, especially under low pressure difference conditions, and can effectively provide the main valve core with the positive force required for closing.

[0047] Preferably, the guide sleeve is connected to a limit seat, and the limit seat and the piston form an abutment and limit cooperation to limit the opening height of the main valve core.

[0048] By adopting the above technical solution, the limit seat and the piston form a limit fit, thereby achieving the purpose of limiting the opening height of the main valve core, and the purpose of flexibly adjusting the opening height of the main valve core can be achieved by adjusting the limit fit relationship between the limit seat and the piston.

[0049] Preferably, the outlet channel is connected to a discharge channel, and the discharge channel is connected from the outlet channel to the outside of the main valve body.

[0050] By adopting the above technical solution, the accumulated liquid or deposited impurities in or near the outlet channel can be released through the discharge channel.

[0051] Preferably, the pilot solenoid valve comprises a pilot valve body, and the pilot valve body and the main valve body are connected with a seismic-resistant bracket.

[0052] By adopting the above technical solution, the seismic-resistant bracket connects the pilot valve body and the main valve body, so that the pilot solenoid valve and the main valve form an integral structure, which can effectively improve the structural stability of the pilot solenoid valve, especially when the pilot solenoid valve itself is high, and can effectively reduce the adverse effects of the vibration of the pilot valve body.

[0053] Preferably, the main valve core is provided with a guide cone, and the guide cone is extended toward the outlet channel and extends into the main valve seat.

[0054] By adopting the above technical solution, when the pilot safety valve is opened, the medium flows into the main valve seat along the guiding cone surface of the guide cone and then enters the outlet channel for discharge. With the help of the drainage effect of the guiding cone surface of the guide cone, the possibility of vortex formation at the water outlet position is reduced, and the medium outflow effect is improved.

[0055] In summary, the present application includes at least one of the following beneficial technical effects: 1. The indicating part of the valve position indicating device is designed as a multi-stage structure to meet the design requirements of long-distance valve position indication, and provide heat insulation and heat dissipation space for the sensing part, and then dissipate heat and cool down through the heat dissipation fins arranged on the mounting shell. At the same time, the sealing of the mounting shell and the valve body is matched to maintain good sealing, so that the valve position indicating device arranged on the safety valve will not be affected by high temperature and high pressure conditions, and can still provide stable and reliable valve position indication function; 2. The sealing ring of the main valve body and the mounting shell of the valve position indicating device form an end face seal, which further improves the sealing performance of the valve position indicating device when used in conjunction with the main valve of the pilot safety valve, thereby further improving the valve position indication stability and reliability of the pilot safety valve, thereby achieving the purpose of improving the overall working stability and reliability of the pilot safety valve; 3. Optimize the connection structure of the mounting shell, the connection structure of the indicator, and the installation matching structure between the indicator and the mounting shell to further improve the heat insulation, heat dissipation and sealing effects of the valve position indicating device; 4. Optimize the valve core structure design of the main valve and the overall structure design of the main valve and the pilot solenoid valve to improve the stability of the sliding movement of the main valve core and the opening accuracy, thereby improving the stability and reliability of the pilot safety valve, and indirectly improve the accuracy and reliability of the valve position displayed by the valve position indicator connected to the main valve core. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 is a schematic diagram of the overall structure of the valve position indicating device in the embodiment of the present application when it is installed on the valve; Figure 2 It is a schematic diagram mainly used to show the connection structure of adjacent indicator rods; Figure 3 It is a schematic diagram mainly used to show the structure of the second shell; Figure 4 yes Figure 1 The overall structure diagram of the valve position indicating device shown in FIG. 1 is a diagram of the overall structure of the valve position indicating device after rotating 90 degrees around the axial direction of the indicating member; Figure 5 It is a schematic diagram mainly used to show the structure of the stuffing box and the disc spring; Figure 6 yes Figure 1 The enlarged schematic diagram of the middle A part; Figure 7 It is a front view of a pilot-operated safety valve with a valve position indicating device in an embodiment of the present application; Figure 8 It is a cross-sectional schematic diagram of the pilot-operated safety valve in the embodiment of the present application cut along the height direction of the safety valve, which is mainly used to show the valve position indicating device, the installation structure of the main valve and the internal structure of the main valve; Fig. 9 yes Figure 8 The enlarged schematic diagram of the middle part B; Fig.10 It is a schematic diagram mainly used to show the structure of the middle cavity; Fig.11 It is a cross-sectional schematic diagram of the pilot-operated safety valve in the embodiment of the present application cut along the length direction of the safety valve, mainly used to show the communication structure between the pressure relief inlet channel and the first chamber; Fig.12 It is a structural schematic diagram of the guide sleeve; Fig.13 It is a schematic diagram of the structure of the piston; Fig.14 It is a structural diagram of the valve core seat; Fig.15 It is a schematic diagram of the structure of the mounting base; Fig.16 It is a side view of a pilot-operated safety valve with a valve position indicating device in an embodiment of the present application.

[0057] Explanation of reference numerals: 1. mounting shell; 11. first shell; 111. first heat dissipating fin; 112. first sliding hole; 113. lifting ring structure; 114. through hole; 115. connecting stud; 12. second shell; 121. second heat dissipating fin; 122. heat dissipating cavity; 123. second sliding hole; 13. third shell; 131. third sliding hole; 132. groove; 14. ear plate structure; 15. guide member; 16. stuffing box structure; 17. disc spring structure; 2. indicator member; 21. indicator rod; 22. adapter sleeve; 221. sleeve flap; 222. clamping groove; 23. trigger member; 24. T-joint; 3. induction member; 31. remote limit switch; 32. near limit switch; 4. main valve; 41. main valve body; 411. connecting opening; 412, plugging part; 42, middle cavity; 421, first chamber; 422, second chamber; 423, pressure relief inlet channel; 424, constant pressure channel; 425 inlet channel; 426, outlet channel; 427, pressure relief return channel; 428, discharge channel; 43, main valve core; 431, guide cone; 44, main valve seat; 5, pilot solenoid valve; 51, pilot valve body; 6, sealing ring; 7, plugging part; 8, guide structure; 81, guide sleeve; 811, drainage hole; 82, piston; 821, piston ring; 822, T-slot structure; 83, valve core seat; 84, four open rings; 85, limit sleeve; 86, fastening screw; 87, split ring; 88, limit seat; 9, elastic drive structure; 91, mounting seat; 92, elastic part; 93, fixed base. DETAILED DESCRIPTION

[0058] The following is combined with Figure 1-16 This application is described in further detail.

[0059] The embodiment of the present application discloses a valve position indicating device.

[0060] Reference Figure 1 As shown, Figure 1 The figure is a schematic diagram of the overall structure of the valve position indicating device when it is installed on the valve. The valve position indicating device is installed at the valve to display the position of the valve core or the opening height of the valve. The valve position indicating device includes a mounting shell 1, one side of which is used to be fixedly connected to the valve body of the valve, and an indicator 2 and a sensor 3 are also arranged on the mounting shell 1, wherein the indicator 2 slides through the mounting shell 1, and at the same time slides through the valve body of the valve connected to the valve position indicating device and is connected to the valve core of the valve, and the sensor 3 is located on the other side of the mounting shell 1 away from the connected valve, and the indicator 2 contacts the sensor 3 in the process of following the sliding movement of the valve core of the valve.

[0061] The indicator 2 is designed as a multi-section structure extending along the movement direction of the valve core of the valve. Specifically, the indicator 2 includes multiple sections of indicator rods 21, and adjacent indicator rods 21 are coaxially detachably connected through an adapter sleeve 22 to meet the design requirements of the indicator 2 with a large axial span, while reducing the difficulty of production and processing at the manufacturing end and the difficulty of subsequent maintenance. In the embodiment of the present application, the indicator 2 includes two sections of indicator rods 21, one section of the indicator rod 21 is relatively short in length, and the indicator rod 21 is used to penetrate into the valve body of the valve and connect to the valve core. The connection structure can be a universal snap-on installation structure, while the other section of the indicator rod 21 with a relatively long length penetrates the valve body of the valve and forms a sliding penetration with the mounting shell 1. The adapter sleeve 22 used to connect the two sections of the indicator rod 21 can always be located in the valve body of the valve, and can also change its position between the valve body and the mounting shell 1 of the valve during the follow-up process of the valve opening and closing.

[0062] Combination Figure 1 and Figure 2 As shown, Figure 2 It is a schematic diagram mainly used to show the connection structure of adjacent indicator rods. In the embodiment of the present application, the adapter sleeve 22 is designed as a split sleeve structure, and the sleeve petals 221 arranged symmetrically on both sides are spliced ​​to form a cylindrical structure. The left and right ends of the sleeve petals 221 are provided with clamping grooves 222. The clamping grooves 222 on both sides are connected in the middle after the sleeve petals 221 are spliced. The ends of the indicator rods 21 are clamped in the corresponding clamping grooves 222. The sleeve petals 221 on both sides are closed to clamp and fix the indicator rods 21 at both ends. Then, the shaft elastic retaining ring is set outside the cylindrical structure to clamp and fix the sleeve petals 221, thereby realizing the connection and fixation of adjacent indicator rods 21.

[0063] Of course, the specific number of indicator rods 21 can be adaptively adjusted according to actual design requirements, and the additional indicator rods 21 can also be detachably connected through the above-mentioned adapter sleeve 22. For example: one or more groups of shorter indicator rods 21 are added to one side of the shorter indicator rod 21 to suit valve sizes of different types and specifications; one or more groups of longer indicator rods 21 are added to one side of the longer indicator rod 21 to meet the design needs of valve position indicating devices of different spans.

[0064] Reference Figure 1As shown, correspondingly, the mounting shell 1 in the embodiment of the present application is also designed as a combined structure, and the mounting shell 1 specifically includes a first shell 11, a second shell 12 and a third shell 13 which are detachably connected, and the first shell 11, the second shell 12 and the third shell 13 are sequentially arranged and connected in series along the sliding movement direction of the indicator 2, wherein the first shell 11 is used to be directly detachably sealed and connected to the valve body of the valve, and the left and right ends of the second shell 12 are detachably connected to the corresponding first shell 11 and the third shell 13, respectively, and the third shell 13 is used to install the sensing element 3. Splitting the mounting shell 1 into multiple groups of shells, in addition to being convenient for processing and manufacturing, assembly and disassembly, and meeting the design requirements of the long span of the valve position indicating device, can also effectively block the heat on one side of the valve from being quickly transferred to the side of the third shell 13 where the sensing element is located.

[0065] Specifically, the end face of the first shell 11 away from the second shell 12 is used for sealing connection with the corresponding end face on the valve body. The specific sealing form can be a sealing ring seal, a packing seal, or other sealing forms. The first shell 11 and the second shell 12, and the second shell 12 and the third shell 13 can be detachably connected by bolt locking. For example, the third shell 13 in the embodiment of the present application is formed with an ear plate structure 14 at one end close to the second shell 12 and the left and right ends of the second shell 12. The second shell 12 and the third shell 13 can be locked by bolting through the ear plate structure 14. The locking connection between the second shell 12 and the third shell 13 can be achieved, and the first shell 11 is provided with a threaded hole at one end close to the second shell 12. The locking connection between the first shell 11 and the second shell 12 can be achieved by bolting through the ear plate structure 14 for locking the second shell 12 and the threaded hole of the first shell 11.

[0066] It should be noted that although the second shell 12 in the embodiment of the present application is an integrated shell structure, in other embodiments, the second shell 12 can be further designed as a combined shell structure, and the specific number of components, shell shape, etc. can be adaptively adjusted according to actual needs, design requirements, etc. The connection between adjacent shells can also adopt the above-mentioned detachable connection structure, or other commonly used snap-on or locking installation structures can be used.

[0067] On this basis, a lifting ring structure 113 for hoisting is also provided on the upper side of the first shell 11, and a through hole 114 is provided on both the upper and lower sides of the first shell 113 along the extension direction of the indicator 2, and the through hole 114 is provided with a connecting stud 115, and the connecting stud 115 is used to be threadedly connected with the valve body to achieve the purpose of hoisting the first shell 11 during subsequent maintenance and repair, and the purpose of connecting and fixing the valve position indicating device and the valve body of the valve. It should be noted that the through hole 114 on the upper side of the first shell 11 and the corresponding connecting stud 115 need to take into account the assembly relationship when designing, while the through hole 114 on the lower side and the corresponding connecting stud 115 can be simply penetrated. In addition to locking the connection between the first shell 11 and the valve body, the connecting stud 115 can also play a temporary load-bearing role during lifting operations. The upper side through hole 114 and the connecting stud 115 with an assembly relationship can effectively prevent the weight of the first shell 11 itself or the overall weight of the installation shell from directly acting on the indicator rod 21 of the indicator 2, thereby improving the safety of inspection and maintenance operations.

[0068] Combination Figure 1 and Figure 3 As shown, Figure 3 It is a schematic diagram mainly used to show the structure of the second shell. In the embodiment of the present application, heat dissipation fins are arranged on the mounting shell 1, and the heat dissipation fins are used to improve the heat dissipation capacity of the valve position indicating device and further protect the sensing member 3 located in the third shell 13. Specifically, the end of the first shell 11 used to connect with the second shell 12 is uniformly formed with a first heat dissipation fin 111 along the circumferential direction, and the second shell 12 is designed as a long straight shell structure with a cavity. The shell body of the second shell 12 is formed with a second heat dissipation fin 121 along its length direction, and the second heat dissipation fin 121 is uniformly arranged along the circumference of the second shell 12. At the same time, the cavity of the second shell 12 can be used as a heat dissipation cavity 122. The purpose of rapid heat dissipation is achieved at the first shell 11 and the second shell 12 by matching the first heat dissipation fin 111 and the second heat dissipation fin 121, and the heat dissipation effect of the mounting shell 1 to the outside is greatly improved by the heat dissipation cavity 122 located in the middle position of the mounting shell 1.

[0069] Combination Figure 1 and Figure 4 As shown, Figure 4 for Figure 1The valve position indicating device shown in the figure is a schematic diagram of the overall structure after being rotated 90 degrees with the axial direction of the indicating member as the axis. In the embodiment of the present application, a first sliding hole 112 is provided in the first shell 11 along the length direction of the shell body, and the first sliding hole 112 is a stepped long straight hole. The relatively long indicating rod 21 of the indicating member 2 slides through the first sliding hole 112 coaxially. The left and right ends of the second shell 12 are provided with second sliding holes 123, and the second sliding hole 123 is a hole structure connected to the heat dissipation cavity 122. The indicating rod 21 passing through the first sliding hole 112 coaxially penetrates into the heat dissipation cavity 122 through the second sliding hole 123 on one side and then coaxially passes out through the second sliding hole 123 on the other side; it should be pointed out that in the embodiment of the present application, the second sliding hole 123 is directly formed by the end chamber opening of the heat dissipation cavity 122. The end surface of the third shell 13 used for connecting with the second shell 12 is penetrated by a third sliding hole 131, and the third sliding hole 131 is a short hole. The third sliding hole 131 is communicated with the groove 132 of the third shell 13, and the sensing element 3 is installed in the groove 132. The indicating rod 21 passing through the second sliding hole 123 passes through the third sliding hole 131 and enters into the groove 132 of the third shell 13 to meet the design requirements of the coordinated use of the indicating element 2 and the sensing element 3.

[0070] It should be noted that, in other embodiments, the specific shapes of the first shell 11, the second shell 12 and the third shell 13 and the forms of the slots, holes and cavity structures can be adaptively adjusted to meet the smooth sliding movement of the indicator rod; taking the second sliding hole 123 as an example, in other embodiments, the second sliding hole 123 can be a short hole opened separately at both ends of the second shell 12, which is connected to the heat dissipation cavity 122, rather than using the end cavity opening of the heat dissipation cavity 122 as the second sliding hole 123. In addition, if multiple detachably connected indicator rods 21 are slidably arranged in the mounting shell 1, it is necessary to consider factors such as the length design and sliding stroke design of the indicator rods 21 to avoid structural interference between the connection structure of adjacent indicator rods 21 and the shell structure.

[0071] Reference Figure 4 As shown, in order to further improve the heat insulation capacity of the valve position indicating device, in the embodiment of the present application, the sliding fit clearance formed by the third shell 13 and the longer indicating rod 21 needs to be smaller than the sliding fit clearance formed by the indicating rod 21 and the first shell 11 and the second shell 12, so as to prevent the heat on the valve side connected to the valve position indicating device from being quickly transferred to the sensing element 3 at the third shell 13 through the sliding fit clearance.

[0072] Combination Figure 4 and Figure 5 As shown, Figure 5It is a schematic diagram mainly used to show the stuffing box structure and the disc spring structure. In order to further improve the stability and sealing of the sliding movement of the indicator rod 21, in the embodiment of the present application, a guide member 15 and a stuffing box structure 16 are also arranged at the first sliding hole 112 of the first housing 11, wherein the guide member 15 is specifically a guide sleeve, and the longer indicator rod 21 and the guide sleeve form a coaxial sliding plug-in fit, and the guide sleeve is integrally embedded at the entrance of the first sliding hole 112 to better play a guiding role, and the stuffing box structure 16 is integrally embedded at the exit of the first sliding hole 112, and the longer indicator rod 21 and the stuffing box structure 16 form a sliding sealing fit, and the stuffing material of the stuffing box structure 16 is selected from high temperature resistant materials. On this basis, the stuffing box structure 16 is also connected to a disc spring structure 17 for compensating for the gap caused by thermal expansion and contraction of the stuffing box structure 16. The disc spring structure 17 is extended as a whole in the heat dissipation cavity 122 of the second shell 12. When a gap appears in the stuffing box structure 16, the disc spring structure 17 releases potential energy to compress the stuffing box structure 16 to obtain a more stable sealing effect.

[0073] It should be noted that in other embodiments, the disc spring structure 17 can be entirely embedded in the first sliding hole 112 of the first shell 11, or partially embedded in the first sliding hole 112 of the first shell 11 and partially extended into the heat dissipation cavity 122 of the second shell 12.

[0074] Combination Figure 1 and Figure 6 As shown, Figure 6 for Figure 1 Enlarged schematic diagram of the middle A part. In the embodiment of the present application, a limit switch is selected as the sensing element 3, and the limit switch specifically includes a distal limit switch 31 and a proximal limit switch 32, and both the distal limit switch 31 and the proximal limit switch 32 are mechanical limit switches. The groove 132 of the third housing 13 is opened downward, and the distal limit switch 31 and the proximal limit switch 32 are both fixed at the bottom wall of the groove 132; when the indicator 2 follows the sliding movement of the valve core until the valve core is fully opened, the longer indicator rod 21 abuts against the distal limit switch 31, and when the indicator 2 follows the sliding movement of the valve core until the valve core is fully closed, the longer indicator rod 21 abuts against the proximal limit switch 32. Both the distal limit switch 31 and the proximal limit switch 32 are connected to the external control system or display system signal through a wire to display the valve position or the valve core opening height of the valve.

[0075] Of course, in other embodiments, a mid-range limit switch may be further arranged in the groove 132 of the third shell 13, and the mid-range limit switch may also be fixed at the bottom wall of the groove 132. The specific arrangement position and arrangement quantity may be adaptively adjusted according to design requirements.

[0076] In addition, combined Figure 4 and Figure 6 As shown, in the embodiment of the present application, the longer indicator rod 21 and the first sliding hole 112 of the first housing 11 and the third sliding hole 131 of the third housing 13 are in rotational cooperation, and the end of the indicator rod 21 that is inserted into the groove 132 of the third housing 13 is installed with a trigger member 23, which is an annular structure. In the embodiment of the present application, the trigger member 23 is specifically a circular ring structure. If the valve core of the valve rotates during the opening and closing movement, the indicator 2 rotates with the valve core, but the trigger member 23 can always stably abut against the triggering sensing member 3 during the rotation of the indicator 2, which has good adaptability and practicality.

[0077] The embodiment of the present application also discloses a pilot-operated safety valve.

[0078] Combination Figure 7 and Figure 8 As shown, Figure 7 This is a front view of a pilot-operated safety valve with a valve position indicating device in an embodiment of the present application. Figure 8 This is a cross-sectional schematic diagram of the pilot safety valve in the embodiment of the present application cut along the height direction of the safety valve, which is mainly used to show the valve position indicating device, the installation structure of the main valve and the internal structure of the main valve. The pilot safety valve includes a main valve 4 and a pilot solenoid valve 5 used in conjunction with each other, the main valve 4 includes a main valve body 41, the pilot solenoid valve 5 includes a pilot valve body 51, and the main valve body 41 and the pilot valve body 51 are integrated to form an integral structure. A central cavity 42 is formed in the main valve body 41, and a main valve core 43 and a main valve seat 44 are installed in the central cavity 42. When the main valve core 43 cooperates with the main valve seat 44, the main valve 4 is closed, and when the main valve core 43 is separated from the main valve seat 44, the main valve 4 is opened. The main valve core 43 is connected to the above-mentioned valve position indicating device. The indicating member 2 of the valve position indicating device is horizontally extended along the movement direction of the main valve core 43. The indicating member 2 is connected to the main valve core 43 and slidably penetrates the main valve body 41. The indicating member 2 cooperates with the sensing member 3 to realize the purpose of displaying the opening and closing state of the main valve core 43, the position of the main valve core 43, and the opening height of the main valve core 43.

[0079] Combination Figure 8 and Fig. 9 As shown, Fig. 9 for Figure 8Enlarged schematic diagram of the middle B part. The end of the main valve body 41 facing the valve position indicating device is provided with a connection opening 411 directly connected to the middle cavity 42. The relatively short indicating rod 21 of the indicating member 2 can extend horizontally into the main valve body 41 through the connection opening 411 and connect with the main valve core 43. Moreover, the opening size of the connection opening 411 can be opened larger to facilitate the subsequent inspection and maintenance of the internal structure of the main valve body 41. The first housing 11 of the valve position indicating device and the corresponding end of the main valve body 41 form an end face sealing fit, thereby sealing the connection opening 411. Specifically, the corresponding end face of the main valve body 41 is embedded and fixed with a sealing ring 6. The embodiment of the present application uses a C-type sealing ring made of high temperature resistant material as the sealing ring 6. The C-type sealing ring is used to achieve a sealed connection between the first housing 11 and the main valve body 41. Even if the opening size of the connection opening 411 is relatively large, a relatively good sealing effect can be obtained.

[0080] Combination Fig. 9 and Fig.10 As shown, Fig.10 4 is a schematic diagram mainly used to show the structure of the middle cavity. In the embodiment of the present application, the middle cavity 42 specifically includes a first cavity 421 and a second cavity 422. Fig. 9 and Fig.11 As shown, Fig.11 The schematic cross-sectional view of the pilot safety valve in the embodiment of the present application is cut along the length direction of the safety valve, which is mainly used to show the connection structure between the pressure relief inlet channel and the first chamber. The first chamber 421 is connected to the valve chamber inlet of the pilot solenoid valve 5 through a pressure relief inlet channel 423, and is connected to the medium inlet of the main valve 41 through a constant pressure channel 424, while the second chamber 422 is connected to the medium inlet of the main valve 41 through an inlet channel 425, and is connected to the medium outlet of the main valve 41 through an outlet channel 426. The main valve core 43 is connected to a guide compensation mechanism, which spans the first chamber 421 and the second chamber 422. Due to the existence of the guide compensation mechanism, although the first chamber 421 and the second chamber 422 are connected, the medium entering the second chamber 422 through the inlet channel 425 will not enter the first chamber 421 in large quantities, and the first chamber 421 mainly replenishes the medium through the constant pressure channel 424. Although the first chamber 421 is connected with the first sliding hole 112 through the connecting opening 411, under the end face sealing effect of the sealing ring 6, the sliding sealing effect of the indicator 2 composed of the stuffing box structure 16 and the disc spring structure 17, and the limitation of the sliding matching relationship between the indicator 2 and the first sliding hole 112, a relatively good sealing effect can be obtained at the connection between the valve position indicating device and the main valve 4.

[0081] Combination Fig. 9 and Fig.11As shown, on this basis, the main valve seat 44 is fixed at the position where the second chamber 422 is connected to the outlet channel 426, and the valve cavity outlet of the pilot solenoid valve 5 is also connected to the outlet channel 426 through a pressure relief return channel 427. When the pilot solenoid valve 5 is controlled to open, a pressure difference is formed between the first chamber 421 and the second chamber 422, and the pressure of the main valve core 43 on the second chamber 422 side is greater than the pressure of the main valve core 43 on the first chamber 421 side, then the main valve core 43 and the main valve seat 44 are separated to open the main valve 4, and the medium discharged by the pilot solenoid valve 5 enters the outlet channel 426 through the pressure relief return channel 427 and is discharged together with the medium discharged by the main valve 4, and when the pilot solenoid valve 5 is closed, the pressure of the main valve core 43 on the first chamber 421 side is greater than the pressure of the main valve core 43 on the second chamber 422 side, and the main valve core 43 and the main valve seat 44 cooperate to close the outlet channel of the main valve 4.

[0082] In addition, refer to Fig.11 As shown, in the embodiment of the present application, the lower portion of the outlet channel 426 is also connected to a discharge channel 428, which is opened vertically downward from the outlet channel 426 and connected to the outside of the main valve body 41. The discharge channel 428 can be normally blocked and closed by a blocking member 412, and the discharge channel 428 can be opened when it is necessary to discharge accumulated liquid or impurities. The blocking member 412 can be a stud structure threadedly connected to the outlet of the discharge channel 428, or can be inserted into a plug at the outlet of the discharge channel, etc.

[0083] Reference Fig. 9 As shown, in the embodiment of the present application, the guide compensation mechanism specifically includes a guide structure 8 and an elastic drive structure 9. The guide structure 8 mainly serves to guide the main valve core 43 to slide stably in the middle cavity 42, while the elastic drive structure 9 mainly serves to assist in driving the main valve core 43 to slide toward the main valve seat 44.

[0084] Combination Fig. 9 and Fig.12 As shown, Fig.12 The figure is a schematic diagram of the structure of the guide sleeve. The guide structure 8 includes a guide sleeve 81 that is fixedly connected in the middle cavity 42. The guide sleeve 81 spans the first chamber 421 and the second chamber 422. One end of the guide sleeve 81 is fixedly connected to the inner wall of the first chamber 421, and the other end extends horizontally into the second chamber 422. The middle opening of the guide sleeve 81 is opened along the horizontal sliding movement path of the main valve core 43, and forms a coaxial sliding plug-in fit with the main valve core 43. On this basis, a piston 82 is coaxially slidably connected in the guide sleeve 81. Correspondingly, a valve core seat 83 is installed at the end of the main valve core 43 away from the main valve seat 44. The main valve core 43 is connected to the piston 82 through the valve core seat 83, and the overall structure formed by the connection between the valve core seat 83 and the piston 82 forms a sliding plug-in fit with the guide sleeve 81.

[0085] It should be pointed out that in the embodiment of the present application, a plurality of drainage holes 811 are evenly arranged on the circumferential side of the guide sleeve 81, and the medium in the first chamber 421 can be discharged through the drainage holes 811 and discharged through the pressure relief inlet channel 423, wherein the drainage hole 811 located at the bottom of the guide sleeve 81 is used to connect the first chamber 421 and the constant pressure channel 424.

[0086] In addition, combined Fig. 9 and Fig.11 As shown, the main valve core is also integrally formed with a guide cone 431, which extends in the direction of the outlet channel 426 and extends into the main valve seat 44; when the pilot safety valve is opened, the medium flows into the main valve seat 44 along the guiding cone surface of the guide cone 431 and then enters the outlet channel 426 for discharge. With the help of the drainage effect of the guiding cone surface of the guide cone 431, the possibility of vortex formation at the water outlet position is reduced, thereby improving the medium outflow effect.

[0087] Combination Fig. 9 and Fig.13 As shown, Fig.13 Schematic diagram of the structure of the piston. In the embodiment of the present application, a T-shaped groove structure 822 is provided on the end of the piston 82 facing the valve position indicating device, and correspondingly, a T-shaped connector 24 is connected to the end of the relatively short indicator rod 21 of the indicator 2 facing the main valve core 43, and the main valve core 43 and the relatively short indicator rod 21 of the indicator 2 are detachably connected through the cooperation of the T-shaped connector 24 and the T-shaped groove structure 822. Of course, in other embodiments, other detachable connection structures that can achieve stable connection can also be used to replace the above-mentioned connection structure in the embodiment of the present application.

[0088] Combination Fig. 9 and Fig.14 As stated, Fig.14 The core seat 83 is fixed to the main valve core 43 by four open rings 84 and a limiting sleeve 85, and the piston 82 is fixedly connected to the valve core seat 83 by a threaded sleeve connection. On this basis, the piston 82 is also connected with a fastening screw 86, which is in abutment with the valve core seat 83 to limit the piston 82 from coming out. The fastening screw 86 is limited by the outer split ring 87, thereby achieving a stable connection between the main valve core 43, the valve core seat 83 and the piston 82.

[0089] In addition, combined Fig. 9 and Fig.13As shown, a piston ring 821 is detachably installed on the circumferential side of the piston 82. In the embodiment of the present application, the piston ring 821 is an elastic sealing ring made of high-temperature resistant material. The elastic snap-fit ​​sleeve of the piston ring 821 is arranged in the slot on the circumferential side of the piston 82, so that the sliding fit clearance formed by the piston ring 821 and the guide sleeve 81 is smaller than the sliding fit clearance formed by the piston 82 and the guide sleeve 81, so as to limit a large amount of medium from directly entering the first chamber 421 through the second chamber 422.

[0090] Reference Fig. 9 As shown, the elastic drive structure 9 includes a mounting seat 91 fixedly mounted in the middle cavity 42, the mounting seat 91 is located as a whole at a position of the first chamber 421 close to the connecting opening 411, and an elastic member 92 is connected to the mounting seat 91 and the piston 82, one end of the elastic member 92 is positioned and clamped on the mounting seat 91, and the other end is coaxially sleeved on the piston 82. In the embodiment of the present application, a spring made of a high temperature resistant material is used as the elastic member 92, and the elastic member 92 can provide a positive force for the main valve core 43 to slide toward the main valve seat 44, especially when the pressure difference between the first chamber 421 and the second chamber 422 is small, so that the main valve core 43 and the main valve seat 44 can be completely closed under the condition of small pressure difference.

[0091] In addition, in the embodiment of the present application, a fixed base 93 is fixed at the position where the first chamber 421 is connected to the connection opening 411. The fixed base 93 is integrally clamped and fixed to the cavity wall of the first chamber 421, and the end face of the fixed base 93 facing the connection opening 411 forms an end face abutment and sealing match with the first housing 11. The end of the guide sleeve 81 facing the connection opening 411 is fixed with a limit seat 88 by screw connection. The limit seat 88 is also clamped and fixed to the cavity wall of the first chamber 421. When the piston 82 slides toward the connection opening 411, the limit seat 88 can form an abutment and limit match with the piston 82 to limit the opening height of the main valve core 43 connected to the piston 82.

[0092] Combination Fig. 9 and Fig.15 As shown, Fig.15 The mounting seat 91 of the elastic driving structure 9 can be fixed on the fixed base 93 or the limiting seat 88. In the embodiment of the present application, the locking mounting seat 91, the limiting seat 88 and the guide sleeve 81 are penetrated by screws, so that the three constitute an integral structure, and are integrally fixed to the cavity wall of the first chamber 421, and are integrally pressed against the fixed base 93, that is, the mounting seat 91 is in direct contact with and pressed against the fixed base 93, so as to achieve the purpose of stable installation.

[0093] Reference Fig.16 As shown, Fig.16It is a side view of a pilot safety valve with a valve position indicating device in the embodiment of the present application. In the embodiment of the present application, the main valve body 41 of the main valve 4 and the pilot valve body 51 of the pilot solenoid valve 5 are both designed as an integral vertical structure, wherein the span of the pilot valve body 51 in the erection height direction is relatively larger, and in order to stably connect the main valve body 41 and the pilot valve body 51, the bottom wall of the pilot valve body 51 and the side wall of the main valve body 41 are fixedly connected with an anti-vibration bracket 7, and the anti-vibration bracket 7 is used to reduce the vibration generated when the pilot valve body 51 is started, and the middle span of the main valve body 41 from the position of the middle cavity 42 to the inlet position of the main valve 4 is also relatively large, resulting in a certain degree of flexibility in the main valve body 41, so the thickness of the main valve body 41 at the position of the constant pressure channel 424 and the inlet channel 425 is increased, so that the first-order natural frequency of the main valve body 41 is increased from about 33Hz to about 53Hz, greatly improving the rigidity of the main valve body 41.

[0094] Of course, in other embodiments, the connection position of the anti-seismic bracket 7 connecting the main valve body 41 and the pilot valve body 51 can be adaptively adjusted according to actual needs.

[0095] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. Valve position indicating device, characterized in that: The invention comprises a mounting shell (1), wherein the mounting shell (1) is provided with an indicator (2) and a sensing element (3) for use in combination, wherein the indicator (2) is used to slide through a valve body and is connected to a valve core to move synchronously with the valve core, and the distal end of the indicator (2) triggers the sensing element (3) during the sliding movement to display the position of the valve core; the indicator (2) is extended along the movement direction of the valve core to form a multi-stage structure, wherein the indicator (2) comprises a plurality of indicator rods (21), and adjacent indicator rods (21) are detachably connected with adapter sleeves (22); the mounting shell (1) is provided with heat dissipation fins, and the mounting shell (1) is also used to be sealed and connected to the valve body.

2. The valve position indicating device according to claim 1, characterized in that: The mounting shell (1) comprises a first shell (11), a second shell (12) and a third shell (13) which are connected in sequence along the moving direction of the indicating member (2); the first shell (11) is used for sealing connection with the valve body; the first shell (11) is provided with a first heat dissipation fin (111); the sensing member (3) is arranged on the third shell (13); and the indicating rod (21) is slidably arranged through the first shell (11), the second shell (12) and the third shell (13).

3. The valve position indicating device according to claim 2, characterized in that: A heat dissipation cavity (122) is formed inside the second shell (12), and second heat dissipation fins (121) are also provided outside the second shell (12).

4. The valve position indicating device according to claim 2, characterized in that: The sliding fit clearance formed between the third housing (13) and the indicator rod (21) that slides through the third housing (13) is smaller than the sliding fit clearance formed between the indicator rod (21) and the corresponding first housing (11) and second housing (12).

5. The valve position indicating device according to claim 2 or 4, characterized in that: The indicating rod (21) is in rotational cooperation with the first shell (11), the second shell (12) and the third shell (13); the indicating rod (21) which slides through the third shell (13) is provided with a triggering member (12); the triggering member (12) is provided as an annular structure; during the sliding movement of the indicating member (2), the triggering member (12) abuts against and triggers the sensing member (3) to display the position of the valve core.

6. The valve position indicating device according to claim 2, characterized in that: The first shell (11) is used for being detachably sealedly connected to the valve body, the second shell (12) is detachably connected to the first shell (11), and the third shell (13) is detachably connected to the second shell (12).

7. The valve position indicating device according to claim 6, characterized in that: The first shell (11) is also provided with a lifting ring structure (113) for lifting; the first shell (11) is provided with a connecting stud (115), and the connecting stud (115) is used for detachable connection with the valve body.

8. The valve position indicating device according to claim 2 or 4, characterized in that: The first housing (11) is also provided with a guide member (15), and the indicator rod (21) and the guide member (15) form a sliding plug-in fit.

9. The valve position indicating device according to claim 8, characterized in that: The first shell (11) is further provided with a stuffing box structure (16), and the indicator rod (21) that slides through the first shell (11) and forms a sliding seal with the stuffing box structure (16).

10. The valve position indicating device according to claim 9, characterized in that: The first shell (11) and / or the second shell (12) is provided with a disc spring structure (17) for compensating for a gap caused by thermal expansion and contraction of the stuffing box structure (16).

11. The valve position indicating device according to claim 5, characterized in that: The sensing member (3) is configured as a limit switch, and the limit switch comprises a distal limit switch (31) and a proximal limit switch (32). When the indicating member (2) slides until the valve core is fully opened, it abuts against and triggers the distal limit switch (31). When the indicating member (2) slides until the valve core is closed, it abuts against and triggers the proximal limit switch (32).

12. A pilot-operated safety valve, comprising a main valve (4) and a pilot solenoid valve (5) used in conjunction with each other, characterized in that: The main valve (4) comprises a main valve body (41), a main valve core (43) is arranged inside the main valve body (41), and the main valve core (43) is connected to a valve position indicating device as described in any one of claims 1 to 11; the indicating member (2) is extended along the movement direction of the main valve core (43) and slidably penetrates the main valve body (41), a sealing ring (6) is arranged outside the main valve body (41), and the mounting shell (1) and the main valve body (41) form an end face sealing fit through the sealing ring (6).

13. The pilot operated safety valve according to claim 12, characterized in that: A central cavity (42) is formed in the main valve body (41); a constant pressure channel (424) and an inlet channel (425) are formed in the central cavity (42) at the inlet of the main valve (4); an outlet channel (426) is formed in the central cavity (42) at the outlet of the main valve (4); the central cavity (42) is also connected to the pilot solenoid valve (5) to form a pressure relief inlet channel (423); the constant pressure channel (424) is connected to the pressure relief inlet channel (423) to form a first chamber (421) in the central cavity (42); the inlet channel (425) is connected to the outlet channel (426) to form a second chamber (421) in the central cavity (42). 422); the main valve core (43) is slidably arranged in the middle cavity (42), and a main valve seat (44) is also arranged in the main valve body (41); when the pilot solenoid valve (5) is closed, the main valve core (43) and the main valve seat (44) cooperate to close the outlet channel (426); when the pilot solenoid valve (5) is opened, a pressure difference is formed between the first chamber (421) and the second chamber (422), and the pressure on the side of the main valve core (43) in the second chamber (422) is greater than the pressure on the side of the main valve core (43) in the first chamber (421), and the main valve core (43) and the main valve seat (44) are separated to open the main valve (4).

14. The pilot operated safety valve according to claim 13, characterized in that: The pilot solenoid valve (5) is also connected to the outlet channel (426) via a pressure relief return channel (427); when the pilot solenoid valve (5) is opened, the medium enters the outlet channel (426) via the pressure relief return channel (427).

15. The pilot operated safety valve according to claim 13, characterized in that: A guide sleeve (81) is provided in the middle cavity (42), a piston (82) is slidably provided on the guide sleeve (81), and the main valve core (43) is connected to the piston (82).

16. The pilot operated safety valve according to claim 15, characterized in that: A plurality of drainage holes (811) are provided on the circumferential side of the guide sleeve (81), and the medium in the first chamber (421) is discharged through the drainage holes (811) and discharged through the pressure relief inlet channel (423). The drainage holes (811) located at the bottom of the guide sleeve (81) are used to connect the first chamber (421) and the constant pressure channel (424).

17. The pilot operated safety valve according to claim 15, characterized in that: The main valve core (43) is clamped with a valve core seat (83), and the valve core seat (83) is connected to the piston (82) and forms a sliding fit with the guide sleeve (81).

18. The pilot operated safety valve according to claim 17, characterized in that: The piston (82) is threadedly connected to the valve core seat (83); a fastening screw (86) is also passed through the piston (82) and connected thereto; the fastening screw (86) and the valve core seat (83) form an abutting fit.

19. The pilot operated safety valve according to claim 15, characterized in that: A piston ring (821) is detachably mounted on the circumferential side of the piston (82), and a sliding fit clearance formed by the piston ring (821) and the guide sleeve (81) is smaller than a sliding fit clearance formed by the piston (82) and the guide sleeve (81).

20. The pilot operated safety valve according to any one of claims 15 to 19, characterized in that: A mounting seat (91) is also provided in the middle cavity (42); an elastic member (92) is connected between the mounting seat (91) and the piston (82); and the elastic member (92) provides a positive force to the main valve core (43).

21. The pilot operated safety valve according to claim 15, characterized in that: The guide sleeve (81) is connected to a limit seat (88), and the limit seat (88) and the piston (82) form an abutment limit fit to limit the opening height of the main valve core (43).

22. The pilot operated safety valve according to claim 13, characterized in that: The outlet channel (426) is connected to a discharge channel (428), and the discharge channel (428) is connected to the outside of the main valve body (41) through the outlet channel (426).

23. The pilot operated safety valve according to claim 12, characterized in that: The pilot solenoid valve (5) comprises a pilot valve body (51), and the pilot valve body (51) and the main valve body (41) are connected via a seismic-resistant bracket (7).

24. The pilot operated safety valve according to claim 13, characterized in that: The main valve core (43) is provided with a flow guide cone (431), and the flow guide cone (431) is extended in the direction of the outlet channel (426) and extends into the main valve seat (44).

Images