Special hydrogen valve capable of realizing on-line leak hunting

Abstract

The invention discloses a hydrogen special valve capable of online leakage detection, and relates to the technical field of valves, the hydrogen special valve comprises a valve body, a valve cover and a support, the valve cover is installed on the valve body, the support is installed on the valve cover, a valve rod is arranged in the valve cover, the valve rod is inserted into the valve body and penetrates through the valve cover and the support at the deep position, and the valve rod is connected with the valve cover. According to the technical scheme provided by the invention, the corrugated pipe is adopted as the main seal of the valve, the packing seal is adopted as the auxiliary seal, and the double-layer seal design is adopted, so that a medium is prevented from leaking out, and the reliability of the valve is improved. And the welding of the corrugated pipe and the sealing of the filler are separated and do not influence each other. Even if the corrugated pipe is damaged or the welding position of the corrugated pipe has a quality problem, the filler can still play a sealing role, so that the safety is relatively high due to double guarantee.

Description

Technical Field

[0001] The invention relates to the technical field of valves, and in particular to a hydrogen-specific valve capable of online leak detection. Background Art

[0002] Hydrocracking is one of the main crude oil refining processes. Since hydrocracking units are operated under high temperature and high pressure, and the medium is flammable and explosive hydrogen and hydrocarbons, the working conditions are very dangerous. Leakage can lead to explosions, which creates great safety hazards. Therefore, higher requirements are placed on the design and structure of valves. The control of internal and external leakage of valves is an important parameter reflecting the quality of valves. Valve manufacturers will take various measures to reduce internal and external leakage of valves. External and internal leakage of hydrogen will not only pollute the environment, but also easily cause fire or explosion. The internal leakage of valves mainly occurs at the valve seat, and the external leakage mainly occurs at the valve stem packing and valve cover gasket. The valve cover gasket is a static seal, which almost does not leak externally. The valve stem is a dynamic seal, and the sealing element is easy to wear, resulting in external leakage. The valve stem seal mostly uses flexible graphite and flexible graphite braided packing, among which the upper and lower circles of the packing use flexible graphite braided rings, and the middle uses molded graphite rings. Stopping the pre-tightening of the packing during the filling process is also one of the measures to ensure good sealing (especially long-term good sealing). Most domestic valves are limited to compacting the packing during packing filling, so their sealing performance deteriorates with the increase of application time. Some foreign Yanmen products use a pre-pressure of 28MPa during packing filling, and are designed with special pre-tightening tools, so they can maintain a good seal for a long time. Of course, if the pre-pressure of the packing is too large, it will increase the wear on the valve stem and increase the opening force of the valve. Therefore, continuous improvements should be made in the selection of packing and the treatment of the surface of the valve stem. The use of packing mainly composed of flexible graphite rings can reduce the wear of the valve stem and also reduce the opening torque of the valve.

[0003] Some valves also use a "live load" structure at the packing gland, that is, a disc spring is added to the bolts of the packing gland, so that the packing gland always exerts a greater pressure on the packing, thereby avoiding leakage caused by loosening of the gland bolts or packing.

[0004] At present, most of the shut-off valves on hydrogenation devices on the market are ordinary stop valves. Ordinary stop valves use packing as the main seal at the valve stem. No matter which technical solution is adopted, leakage is bound to occur after the packing is worn.

[0005] Hydrogen is a light gas with strong flammability. Once hydrogen leaks, it reacts with oxygen in the air and may cause fire or explosion accidents. Therefore, the risks of hydrogen leakage in the environment mainly include fire and explosion. Summary of the invention

[0006] Purpose of the invention: The technical problem to be solved by the present invention is to provide a hydrogen-specific valve capable of online leak detection, thereby solving the problem that the existing valves using packing seals are prone to leakage.

[0007] Technical Solution

[0008] To solve the above problems, the technical solution provided by the present invention is:

[0009] A hydrogen-specific valve capable of online leak detection comprises a valve body, a valve cover and a bracket, wherein the valve cover is mounted on the valve body, and the bracket is mounted on the valve cover. A valve stem is provided in the valve cover and is inserted into the valve body and passes through the valve cover and the bracket deep inside. A bellows assembly is provided on the valve stem located in the valve cover. Two independent hydrogen flow channels are provided in the valve body, an isolation wall is provided between the two independent hydrogen flow channels, a hydrogen through hole is provided on the isolation wall, and a valve disc is connected to one end of the valve stem located in the valve body.

[0010] Furthermore, the bellows assembly consists of a bellows upper seat, a bellows lower seat, and a bellows fixed between the bellows upper seat and the bellows lower seat.

[0011] Furthermore, the wall of the bellows lower seat valve cover at the lower side is fixed, and the bellows upper seat is fixed to the shoulder of the valve stem located at the upper side of the valve cover.

[0012] Furthermore, a guide bracket is provided in the hydrogen through hole.

[0013] Furthermore, the guide bracket is composed of a guide ring located at the center and three supporting brackets distributed at 120 degrees.

[0014] Furthermore, the valve flap is arranged corresponding to the hydrogen through hole, and a limiting rod inserted into the guide ring is provided at the bottom of the valve flap.

[0015] Furthermore, a packing space is provided on the upper side of the valve cover, the packing space is filled with packing, and a packing gland is inserted into the packing space.

[0016] Furthermore, a control space is provided in the bracket, a bearing is fixedly provided in the control space, a valve stem nut is rotatably provided in the bearing, the valve stem passes through the valve stem nut, and the valve stem nut is matched with the valve stem thread.

[0017] Furthermore, a detection space is provided at the top of the valve stem, a hydrogen sensor is provided in the detection space, a hydrogen detection channel is provided in the valve stem, one end of the hydrogen detection channel opens to the side surface of the valve stem on the upper side of the shoulder of the valve stem, and the other end of the hydrogen detection channel opens to the bottom of the detection space.

[0018] Furthermore, a special pressure block that cooperates with the valve stem thread is also provided in the detection space, the special pressure block is located on the upper side of the hydrogen sensor, and a sealing gasket is provided between the hydrogen sensor and the bottom surface of the detection space.

[0019] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0020] The technical solution provided by the present invention adopts a bellows as the main seal of the valve, and a packing seal as an auxiliary seal, and a double-layer sealing design to prevent leakage of the medium and improve the reliability of the valve. The welding of the bellows and the sealing of the packing are separated and do not affect each other. Even if the bellows is damaged or there are quality problems at the welding of the bellows, the packing can still play a sealing role, and the double protection has higher safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0022] Figure 2 For Example 1 of the present invention Figure 1 The enlarged schematic diagram of point A in the middle;

[0023] Figure 3 For Example 1 of the present invention Figure 2 The enlarged schematic diagram of point B in the middle;

[0024] Figure 4 It is a top view of the valve body of embodiment 1 of the present invention. DETAILED DESCRIPTION

[0025] In order to make the technical solution of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Example 1

[0027] Combined with Figure 1-4 A hydrogen-specific valve with online leak detection is used to detect in real time whether the hydrogen in the valve is leaking. It is applicable to working conditions such as hydrogen pipelines with a pressure range of ≤10.0MPa and a temperature of ≤500℃. It includes a valve body 1 and a valve cover 8. The valve cover 8 is installed on the top of the valve body 1. There is a sealing gasket at the connection between the valve cover 8 and the valve body 1, which is fixed and tightened by bolts to achieve sealing between the valve body 1 and the valve cover 8.

[0028] The valve body 8 consists of two independent hydrogen flow passages, one of which occupies the upper half and right half of the valve body 8, and the other independent hydrogen flow passage occupies the lower half and left half of the valve body 8. The left half and right half of the two independent hydrogen flow passages are respectively connected to external hydrogen pipelines or equipment, and the upper half and lower half of the two independent hydrogen flow passages are used for mutual connection and isolation between the two independent hydrogen flow passages.

[0029] An isolation wall 50 for isolating the upper and lower halves of the two independent hydrogen flow channels in the valve body 1 is provided between the upper and lower halves of the two independent hydrogen flow channels. A hydrogen through hole 51 for connecting the upper and lower halves of the two independent hydrogen flow channels is provided on the isolation wall 50. A guide bracket 52 is provided in the hydrogen through hole 51. The guide bracket 52 consists of a guide ring 521 located at the center and three support brackets 522 distributed at 120 degrees. One end of the three support brackets 512 is fixed on the guide ring 511, and the other end is fixed on the inner wall of the hydrogen through hole 51.

[0030] A valve flap 2 is provided in the valve body 1. The valve flap 2 consists of a valve flap body 201 capable of blocking the hydrogen through hole 51 and a limiting rod 202 installed at the bottom of the valve flap body 201. The limiting rod 202 is inserted into a guide ring 511 at the center of the guide bracket 52. The limiting action of the guide ring 511 on the limiting rod 202 enables the limiting rod 202 to slide up and down only while the guide ring 511 remains vertical, so that the valve flap 2 can only move up and down, thereby achieving isolation of two independent hydrogen flow pipes when the valve 2 descends to block the hydrogen through hole 51. The three supporting brackets 522 are used to support the valve flap body 201, so that the user can quickly move the valve flap 2 to the position of the hydrogen through hole 51 blocking the two independent hydrogen flow channels to isolate the independent hydrogen flow channels. When the valve flap 2 rises, the hydrogen through hole 51 connects the two independent hydrogen flow channels, so that hydrogen can flow from one hydrogen flow channel to another.

[0031] A valve stem 5 is provided in the valve cover 8, which passes through the valve cover 8 from top to bottom. A connecting space 203 with an upwardly opening groove structure is provided on the top of the valve disc 2. The lower end of the valve stem 5 is inserted into the connecting space 203 of the valve disc 2. A split ring 3 is provided on the valve stem 5. The split ring 3 is arranged at one end of the valve stem 5 inserted into the connecting space 203 of the valve disc 2. An annular groove for installing the split ring 3 is provided on the lower side of the valve stem 5. The split ring 3 is composed of two semi-circular rings combined in the annular groove to form a complete ring. The inner diameter of the split ring 3 is larger than the outer diameter of the valve stem 5. Therefore, the split ring 3 requires two semi-circular rings to form a complete ring. The split ring 3 is located in the connecting space 203 of the valve disc 2 and protrudes from the valve stem 5. The valve disc gland 4 is inserted into the upper side of the connecting space 203. The valve disc gland 4 is inserted into the diameter gap between the valve stem 5 and the valve disc 2. The bottom end surface of the valve disc gland 4 abuts against the part of the split ring 3 protruding from the valve stem 5. The valve disc gland 4 fixes the valve stem 5 and the valve disc 2 to each other through interference friction fit. The valve disc gland 4 abuts against the split ring 3. The valve disc 2 and the valve stem 5 are fixedly connected together through the valve disc gland 4.

[0032] A bellows space 85 is provided in the valve cover 8, and the valve stem 5 passes through the bellows space 85. A bellows assembly 7 is sleeved on the valve stem 5 located in the bellows space 85. The bellows assembly 7 comprises a bellows upper seat 71 located on the upper side, a bellows lower seat 72 located on the lower side, and a bellows 70 connected between the bellows upper seat 71 and the bellows lower seat 72. The bellows lower seat 72 is fixedly welded to the wall of the valve cover 8 at the bottom end wall of the bellows space 85, and the bellows upper seat 71 is fixedly welded to the shoulder on the valve stem 5. The valve stem 5 drives the bellows assembly 7 to move up and down through the bellows upper seat 71 fixed to the valve stem 5, and the bellows lower seat 72 at one end of the bellows assembly 7 connected to the valve cover 8 will not move.

[0033] A packing space is provided on the upper side of the valve cover 8. The packing space is located at the top of the valve cover 8 and the opening is located on the upper surface of the valve cover 8. The valve stem 5 is inserted into the packing space. The packing space is filled with packing 9. A packing gland 10 is provided on the packing space. The packing gland 10 is inserted into the packing space and abuts against the packing. The packing gland 10 is inserted into the gap between the inner surface of the packing space and the outer surface of the valve stem 2. The packing gland 10 is used to continuously apply pressure to the packing 9, so that the packing 9 still has a sealing effect when the valve stem 5 moves up and down.

[0034] The bellows 70 is used as the main seal of the valve, and the packing 9 is used as the auxiliary seal. The double-layer sealing design prevents leakage of the medium and improves the reliability of the valve. The welding of the bellows and the sealing of the packing are separated and do not affect each other. Even if the bellows is damaged or there are quality problems at the welding part of the bellows, the packing can still play a sealing role. The bellows 70 adopts an internal pressure-bearing design. After the internal pressure-bearing bellows 70 is bent, the direction of the corrugation will not change, which better maintains the elasticity of the original bellows and is not prone to fatigue failure.

[0035] A bracket 12 is provided on the valve cover 8, and a number of double-headed columns 11 are arranged around the bracket 12 and the valve cover 8. The double-headed columns 11 fix the valve cover 8 and the bracket 12 to each other through bolts, and the double-headed columns 11 support the valve cover 8 and the bracket 12 so that a certain distance is maintained between the valve cover 8 and the bracket 12, which is convenient for workers to adjust the packing gland 10.

[0036] The bracket 12 is provided with a control space, the valve stem 5 passes through the control space, a valve stem nut 14 is rotatably provided in the control space, the valve stem nut 14 is installed in the control space through bearings 13 located on both sides, a valve stem nut gland 15 is provided at the top of the control space, the valve stem nut gland 15 is inserted into the control space and abuts against the bearing 13, and the valve stem nut gland 15 presses down the bearing 13 so that the valve stem nut 14 cannot move up and down in the control space. The valve stem nut gland 15 is pressed tightly by the valve stem nut gland 15, and the valve stem nut gland 15 is spot welded to the end face of the bracket 12 to prevent loosening. The valve stem nut 14 and the valve stem 5 are designed with matching threads, and the valve stem nut 14 can drive the valve stem 5 to move up and down when the valve stem nut 14 rotates.

[0037] The top of the stem nut 14 protrudes from the control space, and a handwheel 16 is fixedly provided on the stem nut 14 protruding from the control space. The outer circle of the stem nut 14 and the inner hole of the handwheel 16 are designed with matching square holes, and a nut for tightening the handwheel is designed on the upper end face of the handwheel, thereby fixing the handwheel and the stem nut 14 as an integrated structure. The worker drives the stem nut 14 to rotate by turning the handwheel 16, and the top of the stem 5 passes through and extends out of the handwheel 16. The part of the stem 5 located in the control is provided with a thread matching the stem nut 14, and the rotation of the stem nut 14 can drive the stem 5 to slide up and down.

[0038] A detection space is provided at the top of the valve stem 5, and a hydrogen detection channel 60 is provided inside the valve stem 5. The aperture of the hydrogen detection channel 60 is preferably 2 mm. One end of the hydrogen detection channel 60 is opened on the side of the valve stem 5 on the upper side of the shoulder of the valve stem 5 in the bellows space 85, and the other end of the hydrogen detection channel 60 is opened at the bottom of the detection space.

[0039] A hydrogen sensor 19 is provided in the detection space. A detection head 191 of the hydrogen sensor 19 is inserted into the hydrogen detection channel 60 through the opening of the hydrogen detection channel 60 at the bottom of the detection space. An O-ring 17 for sealing is provided on the detection head 191 of the hydrogen sensor inserted into the hydrogen detection channel 60.

[0040] A sealing gasket 18 located at the bottom of the detection space is provided on the lower side of the hydrogen sensor 19. The sealing gasket 18 is made of PTFE material. A special pressure block 21 is provided on the upper side of the hydrogen sensor 19. The special pressure block 21 is used to press down the hydrogen sensor 19 so that the detection head 191 of the hydrogen sensor 19 will not withdraw from the hydrogen detection channel 60. A rubber pad 20 is provided between the hydrogen sensor 19 and the special pressure block 21. A wiring harness channel is provided in the special pressure block 21. A signal receiver 24 is provided on the special pressure block 21. An indicator light 25 is provided in the signal receiver 24. A wiring harness connector 23 is provided on the indicator light 25. The data transmission wiring harness 22 of the hydrogen sensor 19 is connected to the wiring harness connector 23 through the wiring harness channel.

[0041] A PTFE sealing gasket 18 is provided between the bottom surface of the hydrogen sensor 19 and the bottom surface of the detection space around the end surface hydrogen detection channel 60 port position to prevent the O-ring 17 from failing and the medium from leaking, and the double-layer seal is more reliable. A rubber pad 20 is provided at the upper end of the hydrogen sensor 19, and the hydrogen sensor 19 is pressed by a special pressing block 21 to avoid accidental damage to the hydrogen sensor 19 caused by direct pressing of the hydrogen sensor 19.

[0042] The special pressure block 20 is threadedly connected to the valve stem 5. The hydrogen sensor 19 transmits the detected signal to the signal receiver 24. The signal receiver 24 sends an alarm signal, and the indicator light 25 lights up red to warn the factory inspection personnel that the valve is leaking and to replace the valve in time.

[0043] The bellows assembly 7 ensures that the medium cannot leak into the bellows space and the packing space of the valve cover 8. When the medium leaks into the bellows space in the valve cover 8, the hydrogen detection channel 60 on the valve stem 5 for leak detection will transmit the leaked hydrogen to the detection head 191 of the hydrogen sensor 19, which will be detected by the hydrogen sensor 19. The hydrogen sensor 19 transmits the signal to the signal receiver 24. The signal receiver 24 receives the signal and sends an alarm signal, causing the indicator light 25 to light up red, alerting the factory inspection personnel that the valve is leaking and replacing the valve in time.

[0044] The sensor detection head 191 and the insertion position of the hydrogen detection channel 60 are designed with an O-ring 17 to seal to prevent the leaked hydrogen from diffusing into the air. A PTFE sealing gasket 18 is designed at the lower end surface of the hydrogen sensor 19 and the port of the hydrogen detection channel 60 to form a double-layer seal with the O-ring 17 to prevent the leaked medium from leaking into the air. When the sensor detects a hydrogen leak, the hydrogen sensor transmits the detected signal to the signal receiver, and the signal receiver sends an alarm signal, and the indicator light turns red.

[0045] In order to reduce the impact force of the medium flowing in the valve body 1 on the valve disc 2 and the valve stem 5, which causes the position of the valve disc 2 to shift, the valve adopts a multi-level guide design. In order to ensure that the center of the valve stem 5, the center of the valve disc 2 and the center of the valve body 1 coincide with each other, the guide bracket 52 at the bottom of the valve body 1 is integrally cast. When the valve is processed, the guide bracket 52, the valve seat sealing surface at the hydrogen through hole (i.e. the sealing surface of the valve disc) and the valve body flange stop countersunk hole (i.e. the sealing surface of the valve body and the valve cover) are clamped and processed at one time, eliminating the accumulation of errors caused by multiple clamping; the inner hole of the valve cover and the stepped outer circle matching the valve body are clamped and processed at one time; the valve stem is clamped with one clamp and one top, and the processing is completed by one clamping; the valve disc is clamped with one clamp and one top, and the outer circle, sealing surface, valve stem hole and guide rod are clamped and processed at one time; the assembly datum is unified, the accumulation of assembly errors is eliminated, the valve disc and the valve stem center are guaranteed to remain concentric during the lifting process, the wear of the bellows and the packing is reduced, the fit of the sealing surface is improved, the valve life is guaranteed to be long, and the valve is safe and reliable.

[0046] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A hydrogen-specific valve capable of online leak detection, characterized in that: It includes a valve body, a valve cover and a bracket, the valve cover is installed on the valve body, the bracket is installed on the valve cover, a valve stem is inserted into the valve body and passes through the valve cover and the bracket deep inside the valve cover, a bellows assembly is provided on the valve stem located in the valve cover, two independent hydrogen flow channels are provided in the valve body, an isolation wall is provided between the two independent hydrogen flow channels, a hydrogen through hole is provided on the isolation wall, and a valve disc is connected to one end of the valve stem located in the valve body.

2. A hydrogen-specific valve capable of online leak detection according to claim 1, characterized in that: The bellows assembly consists of a bellows upper seat, a bellows lower seat, and a bellows fixed between the bellows upper seat and the bellows lower seat.

3. A hydrogen-specific valve capable of online leak detection according to claim 2, characterized in that: The wall of the bellows lower seat valve cover at the lower side is fixed, and the bellows upper seat is fixed to the shoulder of the valve stem located at the upper side of the valve cover.

4. The hydrogen-specific valve capable of online leak detection according to claim 1, characterized in that: A guide bracket is arranged in the hydrogen through hole.

5. The hydrogen-specific valve capable of online leak detection according to claim 4, characterized in that: The guide bracket is composed of a guide ring located at the center and three supporting brackets distributed at 120 degrees.

6. A hydrogen-specific valve capable of online leak detection according to claim 5, characterized in that: The valve flap is arranged corresponding to the hydrogen through hole, and a limiting rod inserted into the guide ring is provided at the bottom of the valve flap.

7. The hydrogen-specific valve capable of online leak detection according to claim 1, characterized in that: A packing space is provided on the upper side of the valve cover. The packing space is filled with packing, and a packing gland is inserted into the packing space.

8. The hydrogen-specific valve capable of online leak detection according to claim 1, characterized in that: A control space is provided in the bracket, a bearing is fixedly provided in the control space, a valve stem nut is rotatably provided in the bearing, the valve stem passes through the valve stem nut, and the valve stem nut is matched with the valve stem thread.

9. The hydrogen-specific valve capable of online leak detection according to claim 3, characterized in that: A detection space is provided at the top of the valve stem, a hydrogen sensor is provided in the detection space, a hydrogen detection channel is provided in the valve stem, one end of the hydrogen detection channel opens to the side surface of the valve stem on the upper side of the shoulder of the valve stem, and the other end of the hydrogen detection channel opens to the bottom of the detection space.

10. The hydrogen-specific valve capable of online leak detection according to claim 3, characterized in that: A special pressure block matched with the valve stem thread is also provided in the detection space, and the special pressure block is located on the upper side of the hydrogen sensor. A sealing gasket is provided between the hydrogen sensor and the bottom surface of the detection space.

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