Closed double-buffering-air-cavity air charging device

Abstract

The utility model discloses a closed double-buffer air cavity air charging device, which is characterized in that a buffer cylinder with a compression ring cover, an air hole B, a guide pipe, a lower guide hole, a buffer air hole and a limiting ring is arranged in a central sealing guide ring and a buffer cavity of a spherical valve cover, and a lower supporting ring is arranged below the buffer cylinder. A central air pipe with an air inlet, a ventilation cavity, an air hole A and an air hole D is fixed to a bottom cover, and the bottom cover is fixed below the valve deck through a sealing cylinder. A movable hollow shaft with a pre-tightening thread is fixed on the valve cover, a supporting cylinder with a shaft sleeve is fixed on the central disc, and a pre-tightening spring with a pressing ring and a pre-tightening nut is sleeved on the movable hollow shaft. The other end of the fixed hollow shaft with a compression plug at one end is fixed below an upper cover; and the upper cover is fixed at the upper end of the supporting cylinder. And the fixed hollow shaft penetrates through the lower guide hole and the upper guide hole. The valve port is a spherical surface, and the central disc is fixedly connected with the fixed flange through connecting ribs. The technical scheme is applied to the field of water turbine vacuum area air filling.

Description

TECHNICAL FIELD

[0001] The present invention relates to a device for aerating the vacuum zone of a hydraulic turbine when the turbine is operating off-design or when the turbine is shut down. BACKGROUND

[0002] At present, the water turbine produces harmful vacuum zone when it is running out of rated operating condition or in emergency stop. To eliminate the harmful vacuum zone produced by the water turbine, a large amount of air must be filled into the water turbine vacuum zone through the air charging pipeline in the main shaft of the water turbine when the water turbine produces the vacuum zone, so as to effectively eliminate the harmful vacuum zone produced by the water turbine. The air charging device in the prior art has certain technical defects in actual application: for example, the buffer used on the air charging device in the prior art mostly uses four reverse stop valves with buffer springs on the buffer piston to buffer the closing speed of the valve disc, or uses turbine oil damping buffer. The structure of the buffer piston: the buffer piston is connected with the valve disc through the valve shaft. When the reverse stop valve with the buffer spring on the buffer piston is frequently damaged, the buffer spring is stuck in the hole of the reverse stop valve, or the damaged gasket between the buffer cylinder and the buffer piston cannot make the buffer piston return to the original position, so that the valve disc is not tightly closed, resulting in water leakage of the air charging device. This phenomenon occurs from time to time. More importantly, the processing is complicated, the structure is complex, the four reverse stop valves on the buffer piston are severely worn, the buffer spring on the reverse stop valve is frequently deformed and broken, and the buffer spring mainly buffers the impact force of the reverse stop valve. In addition, the concentricity of the buffer piston and the valve disc is required to be good, and the processing technology is very complex. The existing technology of the air charging device using piston buffer structure has the above technical problems. The existing technical scheme using turbine oil damping buffer causes the turbine oil in the buffer medium to leak extremely fast due to the oil pressure generated by the buffer damping, the buffer technology effect disappears, the valve disc and the valve port collide, the valve shaft is broken, and the risk of water flooding the unit is extremely great. In addition, the buffer structure in the prior art is not closed, and the oxygen in the air is very serious to the oxidation of the lubricating oil of the buffer mechanism, so that the lubricating oil loses the lubricating effect, and the reverse stop piston is frequently stuck. Therefore, the device in the prior art must be frequently cleaned, maintained and oiled to make the buffer structure work normally. Therefore, the maintenance workload of the air charging device in the prior art is huge, and even necessary maintenance cannot be performed on the air charging device in the prior art during the operation of the unit, which brings safety hazards to the operation of the generator. The valve disc of the air device in the prior art adopts flat sealing or conical sealing, and the flat sealing effect is extremely poor. The poor concentricity leads to poor technical effect of the conical sealing, the valve cylinder and the valve seat are connected by welding four thick iron plates, the valve disc and the buffer piston have poor concentricity, and water leakage occurs from time to time. The air charging device in the prior art has four thick fixed plates to fixedly connect the valve cylinder and the valve seat, the buffer piston and the buffer cylinder have large self-weight, so the entire air charging device in the prior art has large self-weight. The air charging device is installed on the upper end of the air charging pipeline of the water turbine main shaft, which aggravates the shaft jumping of the upper end of the main shaft and causes certain damage to the upper guide bearing of the generator unit. In addition, the buffer of the air charging device in the prior art is installed on the spring, which increases the height of the entire air charging device. If this air charging device is installed, the water turbine air charging chamber must be greatly transformed, and the installation and transformation cost is extremely high.The hydraulic power generation field urgently needs an air charging device for hydraulic turbine, which has the advantages of good buffering performance, long service life of buffer, long maintenance-free time, good sealing performance of valve disc, light overall weight, simple installation, no modification of air chamber, and convenient maintenance. SUMMARY

[0003] The application is a technical scheme for satisfying the technical needs in the field of hydraulic power generation, and its main technical features are as follows: a buffer cavity and a sealing guide ring are arranged at the center of the valve cover with a spherical circumference, the upper end of the buffer cylinder with 4-8 air holes B, a compression ring cover, the lower end with a limiting ring and a buffer air hole is arranged in the sealing guide ring, the limiting ring at the lower end of the buffer cylinder is arranged in the buffer cavity, and a retaining ring is arranged on the upper surface of the buffer cavity; the lower supporting ring is fixed on the valve cover below the limiting ring through a counterbore and a threaded hole by means of a bolt, the sealing cylinder is fixed on the center position below the valve cover through an upper flange; the lower end of the central air pipe with air holes A is internally fixed with a fixed plug, the central air pipe is fixed on the center position of the bottom cover through the fixed plug, the upper end of the central air pipe passes through the lower guide hole of the guide pipe, and then the bottom cover is fixed on the upper surface of the lower flange by means of a bolt, the top end of the central air pipe has an air inlet, and the central air pipe has an air passage; the hollow moving shaft with air holes C and pre-tightening threads at the upper end is fixed on the center position of the valve cover through the lower end fixed flange by means of a bolt; the center disc is connected and fixed with the fixed flange through four connecting ribs, and the four connecting ribs have four inflation holes between the center disc and the fixed flange; after the shaft sleeve is placed in the shaft sleeve cavity with the middle supporting ring at the upper surface, the supporting cylinder is fixed on the center disc by means of a bolt; after the hollow moving shaft passes through the through hole of the center disc, the shaft sleeve and the through hole at the upper surface of the middle supporting ring, the hollow moving shaft and the central air pipe are arranged in the supporting cylinder; the pre-tightening spring is sleeved on the hollow moving shaft, the lower end of the pre-tightening spring is arranged on the middle supporting ring, a compression ring is arranged on the upper end of the pre-tightening spring, the pre-tightening nut is screwed on the compression ring through the pre-tightening threads, the valve cover with a spherical surface is closed with the valve port with a spherical surface under the action of the pre-tightening force; the compression plug with compression air holes and an upper guide hole is fixed on the fixed flange at the lower end of the fixed hollow shaft by means of a bolt, the fixed plug is fixed in the fixed hollow shaft with air holes D at the upper end, and the fixed hollow shaft is fixed on the center position below the upper cover through the fixed plug by means of a bolt; the compression plug is arranged in the hollow moving shaft in a sealing mode, and the compression plug can freely slide in the hollow moving shaft; the upper guide hole of the compression plug is sleeved on the central air pipe in a sealing mode, the compression plug can freely slide on the central air pipe, and the compression plug is stationary relative to the valve cover; the upper cover is fixed on the fixed flange at the upper end of the supporting cylinder by means of a bolt; the compression buffer cavity has a distance a of 1-10 mm, and the device is fixed on the upper end of the turbine inflation pipe or the top cover of the turbine by means of a bolt through the flange hole in the fixed flange.A moving part composed of a compression ring cover, 4-8 air holes B, a guide pipe, a plurality of buffer air holes, a limiting ring and a buffer cylinder, can slide up and down in a sealed manner in the buffer cavity and on the central air pipe, replacing the technical features of four reverse stop valves and buffer springs in the prior art, and having the technical effects of triple concentric guidance of the guide pipe, the limiting ring and the sealing guide ring; the sealing guide ring seals the 4-8 air holes B well; the hollow moving shaft and the central air pipe move up and down synchronously with the valve cover; the compression plug is fixed at the lower end of the hollow moving shaft through the fixed hollow shaft and the upper cover, and the distance between the compression plug and the compression ring cover is a, so the compression plug is relatively stationary with the valve cover, the hollow moving shaft and the central air pipe. The central air pipe and the upper guide hole are fixed at a position with good air tightness; the outer surface of the compression plug has good air tightness with the hollow moving shaft, and the hollow moving shaft and the compression plug can slide up and down freely in a sealed manner; the air in the compression buffer cavity can only be discharged through the compression air holes on the compression plug, and the number and diameter of the compression air holes determine the compression buffer effect, the fewer the number of compression air holes, the better the buffer effect, that is, the longer the buffer time, but the buffer time cannot be too long to avoid affecting the closing time of the valve cover; the lower surface of the compression plug is 1-10 mm away from the upper surface of the compression ring cover. The limiting ring has excellent cooperation with the inner diameter of the buffer cavity, and the air in the buffer cavity can only be discharged from the buffer air holes, and the speed of discharge is determined by the number or diameter of the buffer air holes. Under the premise of ensuring that the limiting ring on the buffer cylinder is quickly sucked up without hitting the stop ring, the air in the buffer cavity is discharged as quickly as possible to ensure that the air can quickly enter the compression buffer cavity through the 4-8 air holes B. The central air pipe structure realizes the technical effect of closed use of the buffer air of the device, and the air used for compression buffer is sucked into the compression buffer cavity from the support cylinder through the central air pipe and the air holes B, and after the compression buffer absorbs the elastic potential energy of the pre-tightening spring, these air is discharged back into the support cylinder through the compression air holes, without atmospheric air entering the device; thereby avoiding the large amount of oxygen in the atmospheric air from entering the device, which has a destructive oxidation effect on the lubricating oil, affects the lubricating performance of the lubricating oil, and brings maintenance workload to the device. The device can be used for a long time without maintenance, that is, the original oxidized lubricating oil does not need to be frequently or periodically cleaned on the moving part, and new lubricating oil is not needed to be applied again. The shaft sleeve and the hollow moving shaft cooperate well; the bottom cover and the lower flange are fixed in a sealed manner; the valve port and the valve cover sealing surface adopt spherical sealing, which is superior to the flat sealing and conical sealing in the prior art; the air compression buffer part of the device is installed in the valve cover, which greatly reduces the height of the device compared with the prior art, so that the structure of the air chamber does not need to be modified when the device is selected. The shaft sleeve, the compression plug, the support cylinder, the hollow moving shaft, the fixed hollow shaft and the guide pipe have excellent concentricity.

[0004] The technical effect achieved by the technical solution disclosed in the present application is as follows: when the mixed-flow water turbine and the Kaplan water turbine are in a harmful vacuum zone away from the rated working condition or in a shutdown state, the air charging device of the closed double-buffer air cavity starts to work. When the water turbine generates a vacuum zone, the vacuum degree of the vacuum zone is transmitted to the valve cover of the device through the air charging pipe, and the pressure difference between the vacuum degree and the atmosphere rapidly opens the valve cover. In the process of opening the valve cover, the valve cover compresses the pre-tightening spring through the hollow shaft, the compression ring and the pre-tightening nut. In the process of moving the hollow shaft downward, the lower surface of the compression plug is separated from the upper surface of the compression ring cover, that is, the volume of the compression buffer cavity is increased, so that the compression buffer cavity is instantly formed into a vacuum, the compression ring cover is rapidly sucked up, and the limiting ring compresses the air in the compression buffer cavity. In the process of discharging the air in the buffer cavity through the buffer air hole, the buffer cylinder and the compression ring cover have the buffer technical effect, so that the limiting ring cannot hit the stop ring. After the air in the buffer cavity is completely discharged, the 4-8 air holes B at the upper end of the buffer cylinder are higher than the upper surface of the sealing guide ring, and the air in the supporting cylinder is introduced into the compression buffer cavity through the air holes C, the air holes D, the air inlet, the air cavity, the air holes A and the air holes B. This is the process of opening the valve cover by the vacuum degree generated by the harmful vacuum zone. After the valve cover is opened, the air in the atmosphere is introduced into the harmful vacuum zone through the air inlet and the distance generated by the valve cover. When the suction force of the harmful vacuum zone on the valve cover is balanced with the elastic force generated by the compressed pre-tightening spring, the harmful vacuum zone generated by the water turbine is eliminated, the valve cover no longer moves downward, and the valve cover is instantly in a static state. At this time, the air is no longer introduced into the compression buffer cavity through the air holes B. After the harmful vacuum zone is eliminated, the valve cover stops moving downward. The components composed of the compression ring cover, the buffer cylinder and the limiting ring fall back under the action of the weight. In the process of falling back, the air rapidly enters the buffer cavity through the buffer air hole, the components fall back to the original position, and the 4-8 air holes B are blocked by the inner surface of the sealing guide ring. The valve cover, the hollow shaft and the central air pipe rapidly move upward under the action of the pre-tightening spring from the static state. In this process, the compression ring cover compresses the air in the compression buffer cavity, and the air in the compression buffer cavity can only be discharged from the compression air holes on the compression plug. The speed of discharging the air is determined by the number and aperture of the compression air holes. The more the number and the larger the aperture, the faster the speed of discharging the air, and the faster the speed of closing the valve cover. The fewer the number and the smaller the aperture, the slower the speed of discharging the air, and the slower the speed of closing the valve cover. However, no matter how fast or slow the speed of closing the valve cover, the valve cover cannot hit the valve port when closing, and the air in the compression buffer cavity must absorb all the elastic potential energy of the pre-tightening spring to make the valve cover close to the valve port. The compression air buffer process is the process of absorbing all the elastic potential energy of the pre-tightening spring by compressing the unsaturated air into saturated air. The air completing the compression buffer returns to the supporting cylinder through the compression air hole. The device can buffer an impact force greater than 1000 kg within a distance of 200 mm, so that the device does not have the impact closing phenomenon after charging the harmful vacuum zone of the water turbine with air.The device can fill air into the harmful vacuum area generated by the water turbine in time, smoothly, without resistance and impact sound, so as to eliminate the harm.

[0005] The specification only discloses one of the technical solutions of the application, and other technical solutions obtained by those skilled in the art based on the disclosure of the application without creative labor are within the protection scope of the application.

[0006] The technical solution disclosed by the application perfectly solves the technical defects of the air supplement valve in the prior art, and has the advantages of novelty, creativity and practicality compared with the prior art. The technical solution disclosed by the application will be widely used in the field of eliminating the harmful vacuum area generated by the water turbine by air filling. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 . Main view of the closed double-buffer air cavity air filling device

[0008] Figure 2 . A-A view of the closed double-buffer air cavity air filling device

[0009] Among them:

[0010] 1, buffer cavity 2, bottom cover 3, buffer air hole

[0011] 4, compression ring cover 5, center air pipe 6, air hole A

[0012] 7, fixed plug 8, bolt 9, counterbore

[0013] 10, threaded hole 11, lower guide hole 12, guide pipe

[0014] 13, lower support ring 14, limit ring 15, buffer cylinder

[0015] 16, air hole B 17, lower flange 18, sealing cylinder

[0016] 19, upper flange 20, valve cover 21, spherical surface

[0017] 22, valve port 23, flange hole 24, fixed flange

[0018] 25, air inlet 26, connecting rib 27, center disc

[0019] 28, shaft sleeve cavity 29, shaft sleeve 30, compression plug

[0020] 31, support cylinder 32, movable hollow shaft 33, pre-tightening spring

[0021] 34, air hole C 35, compression ring 36, pre-tightening nut

[0022] 37. Pre-tightening screw 38. Air inlet 39. Upper cover

[0023] 40. Air hole D 41. Through hole 42. Fixed hollow shaft

[0024] 43. Ventilation cavity 44. Upper guide hole 45. Compression air hole

[0025] 46. Middle supporting ring 47. Compression buffer cavity 48. Sealing guide ring

[0026] 49. Blocking ring DETAILED DESCRIPTION:

[0027] Buffer cylinder 15 upper end has 4-8 air holes B16 and compression ring cover 4, compression ring cover 4 is processed with guide tube 12, guide tube 12 has lower guide hole 11, buffer cylinder 15 lower end has 2-4 buffer air holes 3 and limiting ring 14. Buffer cylinder 15 upper end is placed in sealing guide ring 48, buffer cylinder 15 lower end is placed in buffer cavity 1. Through counterbore 9 and threaded hole 10, lower support ring 13 is fixed below buffer cavity 1 with bolt 8. Through upper flange 19 and counterbore 9, sealing cylinder 18 with lower flange 17 is fixed below center position of valve cover 20 with bolt 8. Center air pipe 5 with two air holes A6 at lower end is fixed on fixed plug 7, and then center air pipe 5 is fixed on center position of bottom cover 2 with bolt 8 through counterbore 9 and threaded hole 10. After center air pipe 5 passes through lower guide hole 11, bottom cover 2 is fixed below lower flange 17 with bolt 8. Upper end of moving hollow shaft 32 with pre-tightening thread 37 and air hole C34 is fixed on center position above valve cover 20 with bolt 8 through fixed flange 24. Center disc 27 with through hole 41 is fixed and connected with fixed flange 24 through four connecting ribs 26. After shaft sleeve 29 is placed in shaft sleeve cavity 28 with middle support ring 46 above, upper end of supporting cylinder 31 with fixed flange 24 is fixed on center disc 27 above through counterbore 9 on center disc 27 and threaded hole 10 at lower end of supporting cylinder 31, moving hollow shaft 32 is placed in supporting cylinder 31 after passing through through hole 41 above center disc 27, shaft sleeve 29 and through hole 41 on middle support ring 46, and center air pipe 5 is also in supporting cylinder 31. Pre-tightening spring 33 is sleeved on moving hollow shaft 32, compression ring 35 is placed on upper end of pre-tightening spring 33, pre-tightening nut 36 is screwed on compression ring 35 through pre-tightening thread 37, pre-tightening spring 33 generates pre-tightening force on valve cover 20 and valve port 22, and spherical surface 21 sealing port is in sealing state. Compression plug 30 with compression air hole 45 is fixed at lower end of fixed hollow shaft 42 through fixed flange 24 at lower end of fixed hollow shaft 42 with bolt 8, fixed plug 7 is fixed inside upper end of fixed hollow shaft 42 with air hole D40 at upper end, and bottom cover 39 is fixed on upper end of fixed hollow shaft 42 through counterbore 9 and threaded hole 10 with bolt 8, and fixed hollow shaft 42 must keep good concentricity with related components. Compression plug 30 is placed inside moving hollow shaft 32 through sliding sealing cooperation between outer diameter of compression plug 30 and inner diameter of moving hollow shaft 32, and through hole 44 on compression plug 30 passes through center air pipe 5 and is in sliding sealing cooperation with each other. Bottom cover 39 is fixed on fixed flange 24 at upper end of supporting cylinder 31 with bolt 8. Shaft sleeve 29, moving hollow shaft 32, compression plug 30, through hole 44 on compression plug 30, lower guide hole 11, sealing guide ring 48 and limiting ring 14 have good concentricity. The implementation is completed.

Claims

1. A closed-type double-buffered air-filling device, characterized in that, A buffer chamber and a sealing guide ring are located at the center of the spherical valve cover. A buffer cylinder, with 4-8 air holes (B) at its upper end, a compression ring cover, and a limit ring and buffer air holes at its lower end, is placed in the sealing guide ring. The limit ring at the lower end of the buffer cylinder is placed in the buffer chamber, which is topped with a retaining ring. A lower support ring is bolted to the valve cover below the limit ring through a countersunk hole and threaded hole. The sealing cylinder is fixed to the center of the valve cover below by an upper flange. A fixing plug is fixed inside the lower end of a central air pipe with air holes (A), securing the central air pipe to the bottom cover. Position the central air tube so that its upper end passes through the lower guide hole on the guide tube, then bolt the bottom cover to the lower flange. The central air tube also has an air inlet at the top and a ventilation chamber inside. The movable hollow shaft with an air hole C and pre-tightening thread at its upper end is bolted to the center position on the valve cover via the fixed flange at its lower end. The central disc is connected and fixed to the fixed flange by four connecting ribs, and there are four air inlets between the central disc and the fixed flange. After inserting the bushing into the bushing cavity with the center support ring, bolt the support cylinder to the central disc. The movable hollow shaft then passes through the central disc. After passing through the holes on the shaft sleeve and the center support ring, the hollow moving shaft and the central air pipe are placed inside the support cylinder. A preload spring is placed on the hollow moving shaft, with its lower end on the center support ring. A pressure ring is placed on the upper end of the preload spring, and the preload nut is screwed onto the pressure ring through the preload thread, causing the spherical valve cover and the spherical valve port to close under the preload force. A compression plug with a compressed air hole and an upper guide hole is bolted to the fixing flange at the lower end of the fixed hollow shaft. A fixing plug is fixed at the upper end inside the fixed hollow shaft with air hole D, and bolts are used to secure the plug. The upper end of the fixed hollow shaft is fixed at the center position under the top cover; the outer diameter of the compression plug is placed inside the movable hollow shaft in a sealed manner, and the compression plug can slide freely inside the movable hollow shaft; the upper guide hole on the compression plug is fitted onto the central air pipe in a sealed manner, and the compression plug can slide freely up and down on the central air pipe, while the compression plug is stationary relative to the valve cover; the top cover is fixed to the fixed flange at the upper end of the support cylinder with bolts; the distance 'a' between the compression buffer chambers is 1 to 10 mm, and the device is fixed to the upper end of the turbine air inlet pipe or the top cover with bolts through the flange hole on the fixed flange.

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