Natural gas hydrogen-doped gas leakage intelligent turn-off device

Abstract

The utility model relates to an intelligent shutoff device for natural gas hydrogen-doped gas leakage. The intelligent shutoff device comprises a valve connected to a pipeline, a mixed gas pushing device and a valve shutoff executing mechanism. The gas mixing pushing device is fixed to the rear portion of the valve on the pipeline and comprises a gas chamber and a piston. The gas chamber comprises a first gas cavity in the center, a second gas cavity arranged outside the first gas cavity and separated from the first gas cavity, and a gas mixing cavity; the first gas cavity surrounds the periphery of the pipeline connecting flange, and inert gas is contained in the second gas cavity. The first and second gas cavities are communicated with the inner end of the gas mixing cavity through a gas passage; the piston is embedded in the gas mixing cavity, a sealing gasket is fixed at the inner end of the piston, an elastic pressing piece is pressed at the outer end of the piston, and an outer exhaust hole and a boosting gas output hole which are communicated with the gas mixing cavity are formed in the gas chamber; the valve turn-off executing mechanism comprises a gear and a rack assembly, and the gear is fixedly connected with the valve rotating shaft; the rack body is meshed with the gear, the two ends of the rack body are inserted into the two rack guide sleeves in a sliding mode, and mixed gas input is achieved at the outer end of one rack guide sleeve. The device does not need an external driving air source and is reliable in turn-off.

Description

Technical Field

[0001] The utility model belongs to the field of natural gas hydrogen blending technology and hydrogen transmission and distribution, and specifically relates to an intelligent shut-off device for natural gas hydrogen blending gas leakage. Background Art

[0002] As an ideal energy carrier, hydrogen does not produce carbon dioxide emissions when used as a fuel cell or directly burned as a fuel. However, the storage and transportation of hydrogen is a current technical problem. Whether it is the construction of a pure hydrogen pipeline or the transportation of liquid hydrogen or compressed hydrogen, it will result in very high storage and transportation costs. Therefore, the use of natural gas pipelines to blend hydrogen has become an important research direction for the use of hydrogen energy in various countries. The blending of hydrogen in natural gas pipelines can use natural gas pipelines as a transportation carrier to separate hydrogen in a different place, or directly burn and utilize the mixed natural gas mixed with hydrogen. Moreover, the direction of my country's natural gas pipelines is very consistent with the direction of hydrogen energy transportation, that is, the rich wind and solar resources in the west are converted into hydrogen energy, and then transported to the east for separation or utilization after being mixed into the natural gas pipeline of the West-East Gas Transmission Project.

[0003] Natural gas mixed with hydrogen has a good energy-saving and emission-reduction effect on gas internal combustion engines. According to the research on HCNG (hydrogen-mixed natural gas) internal combustion engine technology by Professor Wang Jinhua and Huang Zuohua of the School of Energy and Power of Xi'an Jiaotong University, when natural gas is mixed with 20% hydrogen during the operation of a natural gas internal combustion engine, the particle concentration is reduced by 55%, NOx is reduced by 85-90%, and the thermal efficiency is increased by 15%. Therefore, adding a certain proportion of hydrogen to natural gas can reduce nitrogen oxides and carbon emissions, and make full use of hydrogen.

[0004] The density of hydrogen is equivalent to 1 / 10 of the density of natural gas, and its molecular weight is relatively small. From the differences in these properties, it can be seen that hydrogen is extremely easy to penetrate and can easily penetrate from the flange seal. At present, the mixing station is equipped with related facilities such as vents, and hydrogen leakage is not easy to be found. When hydrogen is discharged into the air, it is easy to burn when it encounters open flames or electric sparks. In order to solve the hydrogen leakage phenomenon at the hydrogen flange seal, an automatic valve cut-off device is needed.

[0005] Currently, commonly used valve shut-off devices include pneumatic / electric emergency shut-off valves and manual valves. Pneumatic / electric emergency shut-off valves require an external instrument gas source and require hydrogen leakage to be detected to achieve the automatic switching function. Manual valves also require hydrogen to be detected before the valve is manually closed. Both methods require detection instruments to achieve hydrogen leakage cut-off.

[0006] Therefore, according to the above problems, the utility model solves the above technical problems by proposing an intelligent shut-off device for natural gas hydrogen-blended gas leakage. Utility Model Content

[0007] In view of the deficiencies in the prior art, the utility model proposes an intelligent shut-off device for natural gas hydrogen-blended gas leakage which does not require an external driving gas source, does not require equipment interlocking alarm, has a small size, is reliable in shutting off, and is safe and reliable.

[0008] The above-mentioned purpose of the utility model is achieved through the following technical solutions:

[0009] An intelligent shut-off device for natural gas hydrogen-blended gas leakage, comprising a valve connected to a pipeline, a gas mixing pusher, and a valve shut-off actuator;

[0010] The gas mixing pushing device is fixed to the rear of the valve installation position on the pipeline, and includes an air chamber and a piston; the air chamber adopts a cylindrical structure, and includes a first air cavity, at least one second air cavity and at least one gas mixing cavity, the first air cavity is arranged in the middle of the air chamber, and the second air cavity and the gas mixing cavity are arranged outside the first air cavity and separated; the first air cavity surrounds the periphery of the pipeline connection flange, the second air cavity is provided with an inert gas, and the gas mixing cavity is arranged radially; the inner cavity of the first air cavity and the inner cavity of the second air cavity are connected to the inner end of the gas mixing cavity through the gas passage;

[0011] The piston is radially movably embedded in the gas mixing chamber, a sealing gasket is fixed at the inner end of the piston, an elastic pressing piece is arranged at the outer end of the piston in the gas mixing chamber, a wire plug is fixedly connected to the outside of the elastic pressing piece in the gas mixing chamber, the wire plug presses the elastic pressing piece, the elastic pressing piece presses the piston, so that the sealing gasket is pressed against the outer port of the gas passage; an outer exhaust hole and a booster gas output hole communicating with the gas mixing chamber are arranged on the gas chamber;

[0012] The valve shut-off actuator adopts a gear rack transmission mechanism, including a gear and a rack assembly, a connecting hole is provided in the center of the gear, and the gear is fixedly connected to the rotating shaft of the valve through the connecting hole; the rack assembly includes a rack body and two rack guide sleeves, the rack body is arranged on one side of the gear and meshes with the gear, and the two ends of the rack body can be slidably inserted in the two rack guide sleeves respectively, the rack guide sleeve located at the rear end is fixedly supported on the rear auxiliary support plate arranged behind the valve body, and the rack guide sleeve located at the front end is fixedly supported on the front auxiliary support plate arranged in front of the valve body; the outer end of the rack guide sleeve at one end is fixedly installed with a hollow wire plug, and a booster head is provided on the inner side of the hollow wire plug in the rack guide sleeve at this end, the booster head is in movable sealing contact with the inner hole wall of the rack guide sleeve through an O-ring, and the inner end of the booster head is in contact with the corresponding end of the rack body; the hollow wire plug is connected with the outer end of the booster gas output hole on the air chamber through a pipeline to realize the input of the mixed gas.

[0013] Moreover, a guide matching structure is arranged between the other end of the rack body and the inner wall of the corresponding rack guide sleeve. The guide matching structure can adopt a guide key and guide groove insertion matching structure, and the guiding direction of the guide groove is consistent with the moving direction of the rack body.

[0014] Moreover, the mixing chamber adopts a plurality of second air chambers arranged along the circumferential direction, and a fan-shaped area is formed between every two adjacent mixing chambers; the first air chamber is connected with each mixing chamber through a plurality of air passages arranged along the circumference, and the plurality of second air chambers are connected with the plurality of mixing chambers one by one through the plurality of air passages.

[0015] Moreover, there are two groups of rack assemblies, which are arranged on both sides of the gear, and the movement directions of the rack bodies of the two groups of gear assemblies are opposite.

[0016] Moreover, guide grooves are arranged on both sides of the piston, and guide protrusions cooperating with the guide grooves are correspondingly arranged on the side walls on both sides of the gas mixing chamber.

[0017] Moreover, both ends of the air chamber are connected to the pipeline through slip-on flanges, the inner sleeve of the slip-on flange is welded to the pipeline, and the outer sleeve of the slip-on flange is fixedly connected to the end face of the air chamber through screws.

[0018] Moreover, it also includes a cylindrical outer shell, which is tightly sleeved on the outside of the mixed gas propulsion device.

[0019] The advantages and positive effects of the utility model are:

[0020] 1. The utility model sets a first air cavity on the periphery of the flange connection of the pipeline, and sets a second air cavity and a gas mixing cavity which are separated from each other on the periphery of the first air cavity. The second air cavity stores inert gas. The first and second air cavities are connected to the gas mixing chamber through the air passage, and an axially movable piston and a sealing gasket are set to press the port in the gas mixing cavity. When there is gas leakage at the flange connection, the leaked gas mixes with the inert gas, pushing the piston into the gas mixing cavity to achieve external discharge, thereby ensuring the safety of the equipment. In addition, when the external discharge cannot meet the requirements, the rack is pushed to drive the gear to rotate to achieve the closing of the valve. The device is a mechanical automatic closing device, which does not require an external driving gas source and driving power supply to drive the closing, and has the advantages of small size, reliable shutoff, and safety and reliability.

[0021] 2. In the intelligent shut-off device for shutting off leakage of hydrogen-blended natural gas described in the utility model, the valve shut-off execution part adopts the cooperation of gears and racks. This method of shutting off the valve is more convenient than the connecting rod structure, and is easy to process and manufacture. At the same time, the valve is closed by the engagement between the teeth, which can reduce the torque of the driving device, thereby achieving a larger closing torque with a smaller force.

[0022] 2. In the intelligent shut-off device for natural gas hydrogen-blended gas leakage of the utility model, the gas mixing push device is connected by a slip-on flange, and the inner sleeve of the slip-on flange is welded to the pipeline. This structure can ensure the sealing of the device and the simplicity of replacement and maintenance.

[0023] 3. The intelligent shut-off device for natural gas hydrogen-blended gas leakage of the utility model adopts a double thrust device design in the gear rack transmission mechanism, which can achieve the effect of double thrust under the same pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall three-dimensional appearance of the utility model;

[0025] Figure 2 It is an overall three-dimensional longitudinal sectional view of the utility model;

[0026] Figure 3 It is a schematic diagram of the appearance of the utility model without the cylindrical shell;

[0027] Figure 4 It is a cross-sectional schematic diagram of the gas mixing propulsion device of the utility model in a non-leaking state;

[0028] Figure 5 It is a cross-sectional schematic diagram of the gas mixing propulsion device of the utility model in a leakage state;

[0029] Figure 6 It is a partial enlarged view of the installation position of the piston in the gas mixing propulsion device of the utility model;

[0030] Figure 7 It is a schematic diagram of the installation of the gas chamber of the utility model on the pipeline;

[0031] Figure 8 It is a structural schematic diagram of the valve shutoff actuator of the utility model. DETAILED DESCRIPTION

[0032] The structure of the utility model is further described below with reference to the accompanying drawings and through embodiments. It should be noted that the embodiments are descriptive rather than restrictive.

[0033] A natural gas hydrogen-blended gas leakage intelligent shut-off device, see Figure 1-Figure 8 The invention point is: it includes a valve 6 connected to a pipeline 1, a gas mixing driving device 7, and a valve shut-off actuator 3.

[0034] The gas mixing pushing device is fixed to the rear of the valve installation position on the pipeline, and mainly includes an air chamber 7.2 and a piston 7.3. The air chamber adopts a cylindrical structure. The air chamber includes a first air cavity 7.2.1, at least one second air cavity 7.2.2 and at least one gas mixing cavity 7.2.3. The first air cavity is arranged in the middle of the air chamber, and the second air cavity and the gas mixing cavity are arranged outside the first air cavity and separated. The first air cavity is surrounded by the periphery of the pipeline connection flange 8, and is used to realize that the gas after the pipeline leaks is directly discharged into the air chamber without directly leaking out. The second air cavity is equipped with an inert gas. The gas mixing cavity is arranged radially. The inner cavity of the first air cavity and the inner cavity of the second air cavity are connected to the inner end of the gas mixing cavity through the gas passage 7.2.4. Specifically, the gas passage can be arranged radially to realize the internal and external communication between the first air cavity and the gas mixing cavity. An air outlet is provided at the front end of the air chamber corresponding to the position of the second air cavity, and an air inlet 7.2.5 is vertically provided at the front end of the air chamber corresponding to the position of the air passage. The air outlet and the air inlet are connected through an external pipe connected to the outside of the air chamber, so that the inert gas in the second air chamber can enter the air passage through the external pipe.

[0035] The piston is radially movably embedded in the gas mixing chamber, and a sealing gasket 7.6 is fixed to the inner end of the piston. The sealing gasket adopts a polytetrafluoroethylene gasket. An elastic pressing piece 7.5 is arranged at the outer end of the piston in the gas mixing chamber, and a compression spring can be adopted. A thread plug 7.4 is connected to the outside of the elastic pressing piece in the gas mixing chamber through threaded matching. The thread plug presses the elastic pressing piece, and the elastic pressing piece presses the piston, so that the sealing gasket is pressed against the outer port of the gas passage. An external exhaust hole 7.2.6 and a booster gas output hole 7.2.7 connected to the gas mixing chamber are arranged on the gas chamber. The external exhaust hole can extend axially to the front end or rear end of the gas chamber, and the booster gas output hole can extend axially to the front end of the gas chamber.

[0036] The valve shut-off actuator adopts a gear rack transmission mechanism, including a gear 3.2 and a rack assembly. A connecting hole is provided in the center of the gear. The gear is fixedly connected to the rotating shaft of the valve through the connecting hole. The valve can be switched on and off by rotating the gear. The rack assembly mainly includes a rack body 3.1 and two rack guide sleeves 3.3. The rack body is arranged on one side of the gear and meshes with the gear. The two ends of the rack body can be slidably inserted into the two rack guide sleeves respectively. The rack guide sleeve at the rear end is fixedly supported on the rear auxiliary support plate 4 arranged behind the valve body, and the rack guide sleeve at the front end is fixedly supported on the front auxiliary support plate 2 arranged in front of the valve body. The front and rear auxiliary support plates are fixedly fixed on the pipeline. The outer end of the rack guide sleeve at one end is fixedly installed with a hollow wire plug 3.4 through threaded matching. The hollow wire plug has an internal threaded connection hole. A booster head 3.5 is arranged inside the rack guide sleeve at the inner side of the hollow wire plug. The booster head is in movable sealing contact with the inner hole wall of the rack guide sleeve through an O-ring, and the inner end of the booster head is in contact with the corresponding end of the rack body. The hollow wire plug is connected to the outer end of the booster gas output hole on the air chamber through a pipeline to realize the input of the mixed gas. Specifically, an external thread ferrule connector 9 is connected to the outer end of the booster gas output hole, and an external thread ferrule connector is connected to the hollow wire plug. The two external thread ferrule connectors are connected through a stainless steel pipe. The outer end of the rack guide sleeve at the other end is fixedly installed with a solid wire plug 3.6 through threaded matching.

[0037] Furthermore, in order to prevent the rack body from axial deflection during movement, a guide matching structure is set between the other end of the rack body and the inner wall of the corresponding rack guide sleeve. The guide matching structure can adopt a guide key and guide groove insertion matching structure, and the guiding direction of the guide groove is consistent with the moving direction of the rack body.

[0038] In the utility model, the mixing chamber adopts a plurality of air chambers arranged along the circumferential direction, such as four in the attached figure, and a second air chamber in a fan-shaped area is formed between every two adjacent mixing chambers. The first air chamber is connected to each mixing chamber through a plurality of air passages arranged along the circumference, and the plurality of second air chambers are connected to the plurality of mixing chambers one by one through a plurality of air passages. The above-mentioned piston and sealing gasket are embedded in each mixing chamber, and the piston is pressed in the above-mentioned manner, and the outer exhaust hole and booster gas output hole corresponding to each mixing chamber are connected on the air chamber. The advantage of using a plurality of mixing chambers and a plurality of second air chambers is that even if there is a problem with the piston of one mixing chamber, the pistons in other chambers can ensure the normal operation of the device.

[0039] In the above structure, in order to increase the torque for closing the valve, the rack assembly is divided into two groups, and the two groups of rack assemblies are arranged on both sides of the gear, and the movement directions of the rack bodies of the two groups of gear assemblies are opposite, see Figure 6 .

[0040] The above-mentioned parts involved in the device are preferably made of stainless steel, which can meet the requirements of using natural gas and hydrogen at the same time and meet the requirements of outdoor use. The above-mentioned gear and rack body are made of forged steel to improve the rigidity of the device.

[0041] In the above structure, in order to prevent the piston from rotating in the mixed gas chamber, guide grooves are arranged on both sides of the piston, and guide protrusions cooperating with the guide grooves are correspondingly arranged on the side walls of the mixed gas chamber.

[0042] In the above structure, the first air cavity is the connection flange position of the pipeline, and the diameter of the first air cavity is preferably 10 mm larger than the diameter of the connection flange.

[0043] In the above structure, the two ends of the air chamber are connected to the pipeline through the slip-on flange 7.1. Specifically, the inner sleeve 7.1.1 of the slip-on flange is welded to the pipeline, and the outer sleeve 7.1.2 of the slip-on flange is fixedly connected to the end face of the air chamber through screws.

[0044] In addition to the above main technical features, it also includes a cylindrical outer shell 5, which is tightly sleeved on the outside of the mixed gas propulsion device to play a protective role.

[0045] Working principle of the utility model natural gas hydrogen-blended gas leakage intelligent shut-off device:

[0046] First, connect the pipeline with the upstream and downstream, and connect the gas after the natural gas hydrogen-blended gas leakage intelligent shut-off device is installed. When hydrogen leaks at the connecting flange, hydrogen will gather in the first gas chamber, and at the same time, hydrogen will push the piston to move radially outward. As the amount of hydrogen increases, the piston's outward displacement will also increase. During the process of the piston moving outward, the hydrogen in the first gas chamber and the inert gas in the second gas chamber enter the mixing chamber through the gas passage, thereby forming a mixed gas to ensure the safety of the equipment. At the same time, in order to ensure uninterrupted gas supply downstream, the device preferentially empties the gas in the mixing chamber through the external exhaust hole. When the emptying still cannot meet the demand, the gas in the mixing chamber will be input into the rack guide sleeve at the corresponding end through the booster gas output hole, stainless steel pipe and hollow wire plug, driving the booster head to move, the booster head pushes the rack body to move, and the gear is driven to rotate through the tooth meshing, and the gear drives the valve shaft to rotate. When the flange leaks, the valve can be quickly closed to prevent the gas in the pipeline from further leaking and causing safety hazards.

[0047] After the valve is closed, the connecting flange will be repaired. During the repair, loosen the connecting screws between the outer sleeve of the rear slip-on flange and the air chamber, and remove the cylindrical outer shell; then loosen the connecting screws between the outer sleeve of the front slip-on flange and the air chamber and the external connecting pipeline, remove the mixing gas propulsion device, and then repair the connecting flange. After the repair is completed, install the mixing gas propulsion device and the cylindrical outer shell, and then connect the outer sleeves of the slip-on flanges at both ends to the end of the air chamber to complete the repair.

[0048] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. An intelligent shut-off device for natural gas hydrogen-blended gas leakage, characterized in that: It includes a valve connected to the pipeline, a gas mixing pusher, and a valve shutoff actuator; The gas mixing pushing device is fixed to the rear of the valve installation position on the pipeline, and includes an air chamber and a piston; the air chamber adopts a cylindrical structure, and includes a first air cavity, at least one second air cavity and at least one gas mixing cavity, the first air cavity is arranged in the middle of the air chamber, and the second air cavity and the gas mixing cavity are arranged outside the first air cavity and separated; the first air cavity surrounds the periphery of the pipeline connection flange, the second air cavity is provided with an inert gas, and the gas mixing cavity is arranged radially; the inner cavity of the first air cavity and the inner cavity of the second air cavity are connected to the inner end of the gas mixing cavity through the gas passage; The piston is radially movably embedded in the gas mixing chamber, a sealing gasket is fixed at the inner end of the piston, an elastic pressing piece is arranged at the outer end of the piston in the gas mixing chamber, a wire plug is fixedly connected to the outside of the elastic pressing piece in the gas mixing chamber, the wire plug presses the elastic pressing piece, the elastic pressing piece presses the piston, so that the sealing gasket is pressed against the outer port of the gas passage; an outer exhaust hole and a booster gas output hole communicating with the gas mixing chamber are arranged on the gas chamber; The valve shut-off actuator adopts a gear rack transmission mechanism, including a gear and a rack assembly, a connecting hole is provided in the center of the gear, and the gear is fixedly connected to the rotating shaft of the valve through the connecting hole; the rack assembly includes a rack body and two rack guide sleeves, the rack body is arranged on one side of the gear and meshes with the gear, and the two ends of the rack body can be slidably inserted in the two rack guide sleeves respectively, the rack guide sleeve located at the rear end is fixedly supported on the rear auxiliary support plate arranged behind the valve body, and the rack guide sleeve located at the front end is fixedly supported on the front auxiliary support plate arranged in front of the valve body; the outer end of the rack guide sleeve at one end is fixedly installed with a hollow wire plug, and a booster head is provided on the inner side of the hollow wire plug in the rack guide sleeve at this end, the booster head is in movable sealing contact with the inner hole wall of the rack guide sleeve through an O-ring, and the inner end of the booster head is in contact with the corresponding end of the rack body; the hollow wire plug is connected with the outer end of the booster gas output hole on the air chamber through a pipeline to realize the input of the mixed gas.

2. The intelligent shut-off device for natural gas hydrogen-blended gas leakage according to claim 1 is characterized in that: A guide matching structure is arranged between the other end of the rack body and the inner wall of the corresponding rack guide sleeve. The guide matching structure adopts a guide key and a guide groove insertion matching structure. The guide direction of the guide groove is consistent with the moving direction of the rack body.

3. The intelligent shut-off device for natural gas hydrogen-blended gas leakage according to claim 1 is characterized in that: The gas mixing chamber adopts a plurality of second gas chambers arranged along the circumferential direction, and a fan-shaped area is formed between every two adjacent gas mixing chambers; the first gas chamber is connected with each gas mixing chamber through a plurality of gas passages arranged along the circumference, and the plurality of second gas chambers are connected one by one with the plurality of gas mixing chambers through the plurality of gas passages.

4. The intelligent shut-off device for natural gas hydrogen-blended gas leakage according to claim 1 is characterized in that: There are two groups of rack assemblies, which are arranged on both sides of the gear, and the movement directions of the rack bodies of the two groups of gear assemblies are opposite.

5. The intelligent shut-off device for natural gas hydrogen-blended gas leakage according to claim 1 is characterized in that: Guide grooves are arranged on both sides of the piston, and guide protrusions matching with the guide grooves are correspondingly arranged on the side walls of both sides of the gas mixing chamber.

6. The intelligent shut-off device for natural gas hydrogen-blended gas leakage according to claim 1 is characterized in that: The two ends of the air chamber are connected to the pipeline through slip-on flanges, the inner sleeve of the slip-on flange is welded to the pipeline, and the outer sleeve of the slip-on flange is fixedly connected to the end face of the air chamber through screws.

7. The intelligent shut-off device for natural gas hydrogen-blended gas leakage according to claim 1 is characterized in that: It also includes a cylindrical outer shell, which is tightly sleeved on the outside of the mixed gas propulsion device.

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