Freezing cut-off device and inspection and detection device thereof

Abstract

The utility model discloses a freezing cut-off device and an inspection device thereof, the freezing cut-off device is used for cut-off of a pipeline, the freezing cut-off device comprises a liquid nitrogen adding mechanism and a freezing cut-off cavity, the freezing cut-off cavity is arranged on the pipeline in a sleeved mode, and the freezing cut-off cavity comprises a heat exchange cavity, a feed liquid pipe, a liquid nitrogen inlet, a liquid nitrogen outlet, a temperature detection assembly and a heat preservation layer. A liquid nitrogen adding mechanism is arranged on the upstream of the liquid nitrogen inlet and comprises a liquid nitrogen inlet pipe, a liquid nitrogen filling barrel, a pressurizing pipe I and a nitrogen cylinder, the liquid nitrogen inlet pipe is connected to the liquid nitrogen inlet, the liquid nitrogen filling barrel used for containing liquid nitrogen is arranged on the upstream of the liquid nitrogen inlet pipe, and the pressurizing pipe I used for pressurizing the liquid nitrogen filling barrel is arranged on the liquid nitrogen filling barrel; the upstream of the pressurizing pipe I is connected with a nitrogen cylinder. According to the freezing cut-off device, the problems that liquid nitrogen is not easy to add and cannot be continuously supplied are solved, the freezing effect on feed liquid is ensured, and meanwhile, an inspection and detection device is used for more conveniently detecting the freezing effect of the freezing cut-off device on different pipelines.

Description

Technical Field

[0001] The utility model relates to the field of pipeline liquid transportation, in particular to a freezing interception device for liquid in a pipeline and a detection device thereof. Background Art

[0002] The liquid produced by nuclear fuel reprocessing plants is extremely radioactive. The radioactive liquid is not always clear liquid and will produce insoluble slag particles. As time accumulates, it is easy to cause blockage in the pipelines transporting the slag-containing liquid.

[0003] In the prior art, compressed air is often used to clear this type of pipe blockage by blowing the blockage point. However, since the compressed air and liquid pipelines are connected via a three-way nozzle, a shutoff device is often required at the other end of the pipeline to accurately clear the blockage point. This device blocks the flow of liquid on that side, ensuring that the compressed air is blown in the direction of the blockage. Currently, these shutoff devices typically use valves, but these valves are complex and have a high failure rate, making them unsuitable for use in highly radioactive environments. Furthermore, the refrigeration mechanisms used in other industries are bulky and unsuitable for the confined spaces and densely packed pipelines of radioactive reprocessing plants.

[0004] The Chinese patent number CN216868188U is now disclosed, which includes a heat exchange cavity and a cold source. The heat exchange cavity is sleeved on the pipeline and is located at one end or both ends of the pipeline. The heat exchange cavity is provided with a cold source inlet and a cold source outlet. The cold source includes a liquid nitrogen storage tank, which is connected to the cold source inlet for providing liquid nitrogen. The liquid nitrogen in the liquid nitrogen storage tank enters the heat exchange cavity from the cold source inlet and exchanges heat with the liquid inside the pipeline in the heat exchange cavity. The vaporized nitrogen obtained after the heat exchange is discharged from the cold source outlet, and the liquid after heat exchange is frozen.

[0005] The above solution has the following problems:

[0006] 1. The method and corresponding equipment for adding liquid nitrogen are not given. In actual operation, it is difficult to inject liquid nitrogen from the liquid nitrogen tank into the heat exchange cavity.

[0007] 2. Liquid nitrogen cannot be supplied continuously, and the liquid nitrogen is easily exhausted before the liquid in the feed liquid pipe is completely frozen.

[0008] 3. It is difficult to determine the amount of liquid nitrogen required for pipelines of different diameters. Utility Model Content

[0009] The purpose of the present invention is to provide a freezing interception device to solve the problems of difficulty in adding liquid nitrogen and inability to continuously supply liquid nitrogen raised in the above-mentioned background technology.

[0010] The purpose of the present invention is also to provide a testing device for a freezing interception device, which can be used to determine whether the freezing interception effect has been achieved, and to roughly determine the amount of liquid nitrogen used and the time required for freezing by means of experiments.

[0011] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0012] A freezing interception device is used for intercepting flow in a pipeline, comprising a liquid nitrogen adding mechanism and a freezing interception cavity. The freezing interception cavity is sleeved on the pipeline. The freezing interception cavity comprises a heat exchange cavity, a liquid feed pipe, a liquid nitrogen inlet, a liquid nitrogen outlet, a temperature detection component, and a thermal insulation layer. A liquid nitrogen adding mechanism is provided upstream of the liquid nitrogen inlet. The liquid nitrogen adding mechanism comprises a liquid nitrogen inlet pipe, a liquid nitrogen tank, a pressurizing pipe I, and a nitrogen cylinder. The liquid nitrogen inlet pipe is connected to the liquid nitrogen inlet. A liquid nitrogen tank for containing liquid nitrogen is provided upstream of the liquid nitrogen inlet pipe. The liquid nitrogen tank is provided with a pressurizing pipe I for pressurizing the liquid nitrogen tank. A nitrogen cylinder is connected upstream of the pressurizing pipe I. By providing the liquid nitrogen adding mechanism, nitrogen can be used to increase pressure and inject liquid nitrogen into the heat exchange cavity, so that the feed liquid in the liquid feed pipe can be frozen more safely and conveniently.

[0013] Furthermore, the heat exchange cavity is sleeved on the outer wall of the feed-liquid pipe, the heat exchange cavity is provided with a liquid nitrogen inlet, the heat exchange cavity is provided with a liquid nitrogen outlet, the liquid nitrogen outlet is higher than the liquid nitrogen inlet, a cover is provided on the outside of the heat exchange cavity, and an insulation layer is provided between the cover and the heat exchange cavity. An annular baffle is linearly arranged along the axial direction inside the heat exchange cavity, and a plurality of annular baffles are provided, and a through hole is provided on the annular baffle; the temperature detection component includes a temperature detection tube and a temperature detector, one end of the temperature detection tube penetrates the heat exchange cavity and is connected to the outer wall of the feed-liquid pipe, and the temperature detector is installed inside the temperature detection tube for monitoring the temperature of the outer wall of the pipe; by providing the annular baffle and providing the through hole on the annular baffle, the liquid nitrogen can be more evenly distributed inside the heat exchange cavity, and the annular baffle is used to conduct heat, thereby further improving the heat exchange efficiency.

[0014] Furthermore, the liquid nitrogen filling barrel includes a barrel body and a barrel cover, the barrel body and the barrel cover are connected by fasteners, an outer shell is provided on the outside of the barrel body, an insulation layer is provided between the barrel body and the outer shell, a pressure pipe I is connected to the barrel cover, the pressure pipe I passes through the barrel cover, and the pressure pipe I extends into the barrel, and a control valve I is provided on the pressure pipe I. The horizontal height of the liquid nitrogen filling barrel is higher than the heat exchange cavity, and the capacity of the liquid nitrogen filling barrel is greater than the capacity of the heat exchange cavity; by providing the liquid nitrogen filling barrel, the liquid nitrogen added to the heat exchange cavity can be contained, and the insulation layer provided on the barrel body can maintain the temperature in the barrel during the use of the freezing interception equipment to prevent the liquid nitrogen from being consumed too quickly. The pressure pipe I and the control valve I can autonomously control the introduction of nitrogen into the liquid nitrogen filling barrel, thereby increasing the pressure in the barrel, and using the pressure to inject the liquid nitrogen into the heat exchange cavity through the pipeline.

[0015] Furthermore, the barrel cover is provided with a liquid nitrogen filling port for adding liquid nitrogen, and a sealing cover is provided on the liquid nitrogen filling port, and the sealing cover is connected to the barrel cover by a fastener; by providing the liquid nitrogen filling port and the sealing cover, it is convenient to add liquid nitrogen from the liquid nitrogen filling port when the barrel cover is closed, and at the same time, it is prevented that the contact surface between liquid nitrogen and air is too large when the barrel cover is directly opened to add liquid nitrogen into the liquid nitrogen barrel, thereby increasing the evaporation consumption of liquid nitrogen.

[0016] Furthermore, the nitrogen cylinder, the pressure pipe I, the liquid nitrogen filling barrel, the liquid nitrogen inlet pipe and the heat exchange cavity are connected as a whole, the liquid nitrogen inlet pipe is provided with a stop valve I, and the liquid nitrogen outlet pipe is provided with a stop valve II; the nitrogen cylinder gas is used to pressurize the pressure pipe I into the liquid nitrogen filling barrel, and the liquid nitrogen is injected into the heat exchange cavity through the liquid nitrogen inlet pipe using the pressure; by providing stop valves on the liquid nitrogen inlet pipe and the liquid nitrogen outlet pipe, the injection of liquid nitrogen into the heat exchange cavity can be stopped in time when the freezing interception device is inspected and tested.

[0017] Furthermore, a liquid nitrogen observation port is provided on the liquid nitrogen outlet, and the liquid nitrogen observation port is funnel-shaped. By providing the liquid nitrogen observation port, it is possible to directly see whether the amount of liquid nitrogen injected is sufficient. If the liquid nitrogen level is observed at the observation port, it proves that the amount of liquid nitrogen is sufficient. If the liquid nitrogen level is not seen at the observation port, it is necessary to continue to inject liquid nitrogen.

[0018] Furthermore, a heat-conducting material is filled between the inner wall of the liquid feed pipe and the outer wall of the pipe passing through the inside of the liquid feed pipe. During actual use and experiments, there is a gap between the outer wall of the simulation tube and the inner wall of the liquid feed pipe. In order to improve the heat exchange efficiency of the freezing interception device, a heat-conducting material is used to enhance the heat exchange effect between the simulation tube and the liquid feed pipe.

[0019] Furthermore, it includes a pressurized pipe II, a liquid addition port, a simulation pipe, a pressure gauge, a discharge elbow and a liquid tank. The pressurized pipe II is provided with a control valve II. One end of the pressurized pipe II is connected to a nitrogen bottle. The pressurized pipe I and the pressurized pipe II share a nitrogen bottle. The pressurized pipe I and the control valve I form a branch leading to the liquid nitrogen tank. The pressurized pipe II and the control valve II form a branch leading to the inspection and detection device. The other end is connected to the simulation pipe. The lower end of the simulation pipe is connected to a discharge elbow. The pressurized pipe II is provided with a stop valve near the end. Ⅲ, a liquid addition port is provided between the pressure gauge and the stop valve Ⅲ, a stop valve Ⅳ is provided on the liquid addition port, a feeding funnel is provided on the liquid addition port, the discharge elbow includes a horizontal section I, a vertical section I, a horizontal section II and a vertical section II in sequence along the liquid flow direction, and a liquid tank is provided at the end of the discharge elbow; by setting up a testing device, the freezing effect of the freezing interception device under different usage conditions can be determined through designed experiments, and the amount of liquid nitrogen used and the time required for freezing can be adjusted according to the experimental results.

[0020] Furthermore, a quick connector is provided between the simulation tube and the pressurized tube II, and a quick connector is provided between the simulation tube and the discharge elbow. The upper and lower ends of the simulation tube extend out of the upper and lower ends of the liquid tube. Quick connectors are installed at the upper and lower ends of the simulation tube, and simulation tubes of different diameters can be replaced with quick connectors to facilitate experiments on various pipelines.

[0021] Furthermore, the upper end of the vertical section I of the discharge elbow is higher than the upper end of the liquid feed pipe; utilizing the communicating vessel principle, the liquid level in the simulation tube is made higher than the upper end of the liquid feed pipe, so that the liquid feed fills the simulation tube to achieve the best experimental effect.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. The use of liquid nitrogen adding mechanism in conjunction with the freezing interception device can more conveniently inject liquid nitrogen into the heat exchange cavity, solving the problem of liquid nitrogen being difficult to inject into the heat exchange cavity, while reducing the risks brought by manual addition of liquid nitrogen.

[0024] 2. A liquid nitrogen tank is set up to continuously inject liquid nitrogen into the heat exchange cavity to prevent the liquid nitrogen from being exhausted when the liquid in the tube is not completely frozen, thereby ensuring the freezing effect of the liquid.

[0025] 3. The inspection and testing device can be used to experimentally determine the actual effect of the freezing interception device when used in different pipe diameters. At the same time, the test can also be used to roughly determine the amount of liquid nitrogen required to freeze the liquid and the time required for complete freezing. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the freezing interception device and its inspection and detection device of the utility model;

[0027] Figure 2 This is a schematic diagram of the freezing interception cavity of the present utility model;

[0028] Figure 3 This is a cross-sectional view of the freezing interception cavity of the present utility model;

[0029] Figure 4 It is a schematic diagram of the combination of the heat exchange cavity, the liquid pipe and the temperature detection pipe;

[0030] Figure 5 This is a schematic diagram of the combination of a nitrogen gas cylinder and a liquid nitrogen barrel;

[0031] Figure 6 It is a schematic diagram of the inspection and detection device combination of the freezing interception cavity and the freezing interception device;

[0032] In the figure, 1-freezing interception cavity, 2-heat exchange cavity, 3-liquid material pipe, 4-liquid nitrogen inlet, 5-liquid nitrogen outlet, 6-temperature detection tube, 7-insulation layer, 8-cover, 9-annular partition, 10-through hole, 11-nitrogen bottle, 12-pressurization pipe I, 13-control valve I, 14-liquid nitrogen filling barrel, 15-barrel body, 16-barrel cover, 17-liquid nitrogen filling port, 18-sealing cover, 19-liquid nitrogen inlet pipe, 20 -Stop valve I, 21-Liquid nitrogen observation port, 22-Stop valve II, 23-Pressure pipe II, 24-Control valve II, 25-Pressure gauge, 26-Liquid addition port, 27-Feeding funnel, 28-Stop valve III, 29-Stop valve IV, 30-Quick connector, 31-Simulation tube, 32-Discharge elbow, 33-Horizontal section I, 34-Vertical section I, 35-Horizontal section II, 36-Vertical section II, 37-Liquid tank. DETAILED DESCRIPTION

[0033] The technical solution of the present utility model will be further described below with reference to the accompanying drawings.

[0034] like Figure 1-5 As shown, a freezing interception device is used for intercepting flow in a pipeline, comprising a liquid nitrogen adding mechanism and a freezing interception chamber 1. The freezing interception chamber 1 is sleeved on the pipeline. A heat-conducting material is filled between the inner wall of the liquid feed pipe 3 and the outer wall of the pipeline passing through the inner side of the liquid feed pipe 3, thereby enabling more efficient heat exchange between the pipeline and the freezing interception device. The heat-conducting material can be made of metal powder or metal wire of the same material as the freezing interception device.

[0035] The freezing interception chamber 1 includes a heat exchange chamber 2, a liquid feed pipe 3, a liquid nitrogen inlet 4, a liquid nitrogen outlet 5, a temperature detection component, and an insulation layer 7. A liquid nitrogen addition mechanism is provided upstream of the liquid nitrogen inlet 4. The liquid nitrogen addition mechanism cooperates with the freezing interception device to more conveniently inject liquid nitrogen into the heat exchange chamber 2, solving the problem of liquid nitrogen being difficult to inject into the heat exchange chamber 2 and reducing the risks associated with manual addition of liquid nitrogen.

[0036] The liquid nitrogen adding mechanism includes a liquid nitrogen inlet pipe 19, a liquid nitrogen filling barrel 14, a pressurizing pipe I 12 and a nitrogen cylinder 11. The liquid nitrogen inlet pipe 19 is connected to the liquid nitrogen inlet 4. A liquid nitrogen filling barrel 14 for containing liquid nitrogen is provided upstream of the liquid nitrogen inlet pipe 19. The level of the liquid nitrogen filling barrel 14 is higher than the heat exchange cavity 2, so that the liquid nitrogen in the liquid nitrogen filling barrel 14 can more easily enter the heat exchange cavity 2. The capacity of the liquid nitrogen filling barrel 14 is greater than the capacity of the heat exchange cavity 2, ensuring that there is sufficient liquid nitrogen in the liquid nitrogen filling barrel 14 to fill the heat exchange cavity 2, and there is also excess liquid nitrogen for continued replenishment after the liquid nitrogen in the heat exchange cavity 2 evaporates;

[0037] The liquid nitrogen filling barrel 14 includes a barrel body 15 and a barrel cover 16, which are connected to the barrel body 15 and the barrel cover 16 by fasteners, which can be bolts and nuts. A shell is provided on the outside of the barrel body 15, and an insulation layer 7 is provided between the barrel body 15 and the shell. The barrel cover 16 is provided with a liquid nitrogen filling port 17 for adding liquid nitrogen, and a sealing cover 18 is provided on the liquid nitrogen filling port 17. The sealing cover 18 is connected to the barrel cover 16 by fasteners, which can be bolts and nuts. The liquid nitrogen filling barrel 14 is provided with a pressurized pipe Ⅰ12 for conveying nitrogen into the liquid nitrogen filling barrel 14, and the pressurized pipe Ⅰ12 passes through the barrel cover 16 and extends into the barrel. , a nitrogen cylinder 11 is connected to the upstream of the pressure pipe I 12, and a control valve I 13 is provided on the pressure pipe I 12. The control valve I can be an electric remote control valve, so that the staff can remotely operate to inject liquid nitrogen into the freezing interception cavity, which is simpler and safer to operate; a liquid nitrogen observation port 21 is provided on the liquid nitrogen outlet 5, and the liquid nitrogen observation port 21 is funnel-shaped. In other embodiments, the liquid nitrogen observation port 21 can also be of other shapes, as long as the liquid nitrogen level can be observed. If the liquid nitrogen level is observed at the observation port, it proves that the amount of liquid nitrogen is sufficient. If the liquid nitrogen level is not seen at the observation port, it is necessary to continue to inject liquid nitrogen;

[0038] The heat exchange cavity 2 of the freezing interception cavity 1 is sleeved on the outer wall of the liquid-feed pipe 3. The heat exchange cavity 2 is provided with a liquid nitrogen inlet 4 and a liquid nitrogen outlet 5. The liquid nitrogen outlet 5 is higher than the liquid nitrogen inlet 4, so that the liquid nitrogen can fill the entire heat exchange cavity 2 from bottom to top. A cover 8 is provided on the outside of the heat exchange cavity 2, and an insulation layer 7 is provided between the cover 8 and the heat exchange cavity 2. An annular baffle 9 is linearly provided inside the heat exchange cavity 2 along the axial direction. There are multiple annular baffles 9, and a through hole 10 is provided on the annular baffle 9. By providing the annular baffle 9 and the through hole 10 on the annular baffle 9, the liquid nitrogen can be more evenly injected into the interior of the heat exchange cavity 2. At the same time, the annular baffle 9 is used to conduct heat, thereby further improving the heat exchange efficiency.

[0039] The temperature detection assembly includes a temperature detection tube 6 and a temperature detector. One end of the temperature detection tube 6 penetrates the heat exchange cavity 2 and is connected to the outer wall of the liquid feed pipe 3. The temperature detector is installed inside the temperature detection tube 6 and is used to monitor the temperature of the outer wall of the pipe. The temperature detector includes a thermocouple and a display screen. The thermocouple is arranged inside the temperature detection tube 6 and is used to measure the temperature of the outer wall of the liquid feed pipe 3. The display screen is arranged outside the temperature detection tube 6. The thermocouple is electrically connected to the display screen and is used to display the measured temperature of the outer wall of the liquid feed pipe 3 on the display screen.

[0040] The nitrogen cylinder 11, the pressurizing pipe I 12, the liquid nitrogen filling barrel 14, the liquid nitrogen inlet pipe 19 and the heat exchange cavity 2 are connected as a whole to ensure that when the nitrogen cylinder 11 is used to pressurize the liquid nitrogen filling barrel 14, there will be no leakage of nitrogen and liquid nitrogen from the connection points of the various components. A stop valve I 20 is provided on the liquid nitrogen inlet pipe 19, and a stop valve II 22 is provided on the liquid nitrogen outlet pipe 5. The gas from the nitrogen cylinder 11 is pressurized into the liquid nitrogen filling barrel 14 through the pressurizing pipe I 12, and the liquid nitrogen is injected into the heat exchange cavity 2 through the liquid nitrogen inlet pipe 19 by pressure. By arranging stop valves on the liquid nitrogen inlet pipe 19 and the liquid nitrogen outlet pipe 5, the injection of liquid nitrogen into the heat exchange cavity 2 can be stopped in time when the freezing interception device is inspected and tested.

[0041] like Figure 1-6 As shown, a test and inspection device for a freezing interception device includes a pressurized pipe II 23, a liquid addition port 26, a simulation pipe 31, a pressure gauge 25, a discharge elbow 32, and a liquid tank 37. A control valve II 24 is provided on the pressurized pipe II 23. The control valve II can be an electric remote control valve, so that the staff can remotely operate to inject liquid nitrogen into the freezing interception cavity, which is simpler and safer to operate. One end of the pressurized pipe II 23 is connected to the nitrogen bottle 11. The pressurized pipe I 12 and the pressurized pipe II 23 share a nitrogen bottle 11. The pressurized pipe I 12 and the control valve I 13 form a passage to the liquid nitrogen filling barrel. 14, the pressurized pipe II 23 and the control valve II 24 form a branch leading to the inspection and detection device, the other end of the pressurized pipe II 23 is connected to the simulation pipe 31, and the lower end of the simulation pipe 31 is connected to the discharge elbow 32; by setting up the inspection device, the freezing effect of the freezing interception device under different usage conditions can be determined through design experiments, and the amount of liquid nitrogen used and the freezing time required can be adjusted according to the experimental results. During the experiment, a liquid with a freezing point close to that of the feed liquid in the pipeline can be selected. In this embodiment, a 0.5 mol / L sodium nitrate aqueous solution is selected as the experimental simulated feed liquid;

[0042] A quick connector 30 is provided between the simulation tube 31 and the pressurized tube II 23, and a quick connector 30 is provided between the simulation tube 31 and the discharge elbow 32. The upper and lower ends of the simulation tube 31 extend out of the upper and lower ends of the liquid feed tube 3. The quick connectors 30 are installed on the upper and lower ends of the simulation tube 31. The quick connectors 30 can be used to replace simulation tubes 31 of different diameters, so as to conduct experiments on various pipelines.

[0043] A stop valve III 28 is provided near the end of the pressurizing pipe II 23, a liquid addition port 26 is provided between the pressure gauge 25 and the stop valve III 28, a stop valve IV 29 is provided on the liquid addition port 26, and a feeding funnel 27 is provided on the liquid addition port 26. The funnel shape facilitates pouring the simulated liquid. In other embodiments, the feeding funnel can also be replaced with other forms, such as a pipe directly connected to the simulated liquid tank.

[0044] The discharge elbow 32 includes a horizontal section I 33, a vertical section I 34, a horizontal section II 35 and a vertical section II 36 in sequence along the flow direction of the liquid. The upper end of the vertical section I 34 of the discharge elbow 32 is higher than the upper end of the liquid pipe 3. By utilizing the communicating vessel principle, the liquid level in the simulation pipe 31 is higher than the upper end of the liquid pipe 3, so that the liquid fills the simulation pipe 31 to achieve the best experimental effect. A liquid tank 37 is provided at the end of the discharge elbow 32 for containing the liquid discharged after the test.

[0045] The freezing interception device provided by the present invention is used as follows: when in use, compressed air at 60-70°C is first introduced into the heat exchange cavity 2 from the liquid nitrogen inlet 4 to purge the interior of the heat exchange cavity 2 and remove residual moisture in the heat exchange cavity 2. The freezing interception cavity 1 is then placed on the pipeline that requires freezing interception. After the entire freezing interception device is assembled, liquid nitrogen is added to the liquid nitrogen barrel 14 in an amount greater than the volume of the heat exchange cavity 2. The sealing cover 18 on the barrel cover 16 is then closed and secured with fasteners. Open the control valve I13 on the pressurizing pipe I12, the stop valve I20 at the upper end of the liquid nitrogen inlet pipe 19, and the stop valve II22 on the liquid nitrogen outlet pipe 5. Then, open the pressure reducing valve of the nitrogen cylinder 11, and introduce nitrogen into the liquid nitrogen tank 14 through the pressurizing pipe I12 to increase the air pressure in the liquid nitrogen tank 14. Use the air pressure to press the liquid nitrogen in the liquid nitrogen tank 14 into the heat exchange cavity 2 of the freezing interception device through the liquid nitrogen inlet pipe 19. Continue to introduce nitrogen until the liquid nitrogen level can be seen from the liquid nitrogen observation port 21. Then, slowly close the pressure reducing valve of the nitrogen cylinder 11 to reduce the amount of nitrogen until the speed of nitrogen introduction is almost equal to the speed of liquid nitrogen evaporation, so that the liquid nitrogen level can always be seen at the liquid nitrogen observation port 21.

[0046] After liquid nitrogen is injected into the heat exchange cavity 2, the reading on the display screen of the temperature detector in the temperature detection tube 6 is observed. When the temperature is maintained at the temperature, the freezing and interception of the liquid in the tube is completed.

[0047] After clearing the blockage point, close the control valve I13 and the stop valve I20 in sequence, keep the stop valve II22 open, and allow the liquid nitrogen in the heat exchange cavity 2 to evaporate naturally. Leave it at room temperature for a period of time to allow the pipeline in the liquid pipe 3 to return to room temperature, and then remove the freezing interception device.

[0048] The use process of the inspection and detection device of the freezing interception device provided by the present invention is as follows: when in use, first use 60-70°C compressed air to pass into the heat exchange cavity 2 from the liquid nitrogen inlet 4 to purge the interior of the heat exchange cavity 2 to remove the residual moisture in the heat exchange cavity 2, then assemble the freezing interception device, and then connect the inspection and detection device to the freezing interception device;

[0049] A 0.5 mol / L sodium nitrate aqueous solution was used as the simulated feed liquid. The stop valve IV 29 on the feed liquid addition port 26 and the stop valve III 28 on the pressure pipe were opened, and the sodium nitrate aqueous solution was poured into the feeding funnel 27 until the simulated tube 31 was filled with the sodium nitrate aqueous solution. The control valve 2 on the pressure pipe was first closed, and then the freezing interception device was immediately started according to the above-mentioned operating procedures of the freezing interception device. The amount of liquid nitrogen added to the liquid nitrogen tank 14 was recorded, and the time for the sodium nitrate to be completely frozen was simultaneously calculated.

[0050] When the temperature of the temperature detector remains constant at -85°C to -95°C, close control valve I13 and shutoff valve I20, then open shutoff valve II22 on pressurized pipe I12. Use the bubble method to test for leaks: open the pressure reducing valve of nitrogen cylinder 11, introduce 0.3 MPa compressed nitrogen into dummy pipe 31, and insert the end of discharge elbow 32 into liquid tank 37 containing liquid, submerging the pipe opening in the liquid. If there are no leaks and no bubbles appear in liquid tank 37, then the amount of liquid nitrogen used and the time required for freezing this freezing interception device are sufficient to completely freeze the liquid in the pipe.

[0051] After the experiment, keep the control valve I13 and the stop valve I20 closed, keep the control valve II24 and the stop valve II22 open, and allow the liquid nitrogen in the heat exchange cavity 2 to evaporate naturally. Leave it at room temperature for a period of time to thaw the sodium nitrate aqueous solution, then close the stop valve IV29, open the control valve II24 and the stop valve III28, replace the nitrogen bottle 11 connected to the pressurized pipe II23 with a compressed air device, use compressed air to blow the sodium nitrate aqueous solution completely into the liquid tank 37, and then dry the condensed water inside the heat exchange cavity 2.

[0052] In this embodiment, liquid nitrogen was introduced at a positive pressure of 0.05 to 0.1 MPa. After 3 minutes, the temperature inside the freezing chamber reached -50°C. After 15 minutes of continuous introduction of liquid nitrogen, the temperature inside the freezing chamber reached -85°C to -95°C. At 15 minutes, the sodium nitrate aqueous solution in the simulated tube 31 began to gradually crystallize, and after 25 minutes, the liquid was completely frozen. A leak test was performed by introducing 0.3 MPa compressed air into the outlet of the simulated tube 31. A bubble test revealed no abnormal noise or gushing, ensuring that the frozen area was completely frozen and leak-proof.

Claims

1. A freezing interception device for intercepting flow in a pipeline, comprising a liquid nitrogen adding mechanism and a freezing interception cavity (1), wherein the freezing interception cavity (1) is sleeved on the pipeline, and the freezing interception cavity (1) comprises a heat exchange cavity (2), a liquid feed pipe (3), a liquid nitrogen inlet (4), a liquid nitrogen outlet (5), a temperature detection component and a thermal insulation layer (7), characterized in that: A liquid nitrogen adding mechanism is provided upstream of the liquid nitrogen inlet (4), and the liquid nitrogen adding mechanism comprises a liquid nitrogen inlet pipe (19), a liquid nitrogen filling barrel (14), a pressurizing pipe I (12) and a nitrogen gas cylinder (11). The liquid nitrogen inlet pipe (19) is connected to the liquid nitrogen inlet (4). A liquid nitrogen filling barrel (14) for containing liquid nitrogen is provided upstream of the liquid nitrogen inlet pipe (19). A pressurizing pipe I (12) for pressurizing the liquid nitrogen filling barrel (14) is provided on the liquid nitrogen filling barrel (14). The pressurizing pipe I (12) is connected upstream of the nitrogen gas cylinder (11).

2. A freezing interception device according to claim 1, characterized in that: The heat exchange cavity (2) is sleeved on the outer wall of the liquid-feed pipe (3); a liquid nitrogen inlet (4) is provided on the heat exchange cavity (2); a liquid nitrogen outlet (5) is provided on the heat exchange cavity (2); the liquid nitrogen outlet (5) is higher than the liquid nitrogen inlet (4); a cover (8) is provided on the outer side of the heat exchange cavity (2); an insulation layer (7) is provided between the cover (8) and the heat exchange cavity (2); an annular baffle (9) is linearly provided inside the heat exchange cavity (2) along the axial direction; a plurality of annular baffles (9) are provided; and a through hole (10) is provided on the annular baffle (9); the temperature detection assembly comprises a temperature detection tube (6) and a temperature detector; one end of the temperature detection tube (6) penetrates the heat exchange cavity (2) and is connected to the outer wall of the liquid-feed pipe (3); the temperature detector is installed inside the temperature detection tube (6) and is used to monitor the temperature of the outer wall of the pipe.

3. A freezing interception device according to claim 2, characterized in that: The liquid nitrogen filling barrel (14) includes a barrel body (15) and a barrel cover (16), the barrel body (15) and the barrel cover (16) are connected by fasteners, an outer shell is provided on the outer side of the barrel body (15), and an insulation layer (7) is provided between the barrel body (15) and the outer shell, a pressure pipe I (12) is connected to the barrel cover (16), the pressure pipe I (12) passes through the barrel cover (16), and the pressure pipe I (12) extends into the barrel, and a control valve I (13) is provided on the pressure pipe I (12), the horizontal height of the liquid nitrogen filling barrel (14) is higher than the heat exchange cavity (2), and the capacity of the liquid nitrogen filling barrel (14) is greater than the capacity of the heat exchange cavity (2).

4. A freezing interception device according to claim 3, characterized in that: The barrel cover (16) is provided with a liquid nitrogen filling port (17) for adding liquid nitrogen, and the liquid nitrogen filling port (17) is provided with a sealing cover (18), and the sealing cover (18) is connected to the barrel cover (16) via a fastener.

5. A freezing interception device according to claim 4, characterized in that: The nitrogen cylinder (11), the pressurizing pipe I (12), the liquid nitrogen filling barrel (14), the liquid nitrogen inlet pipe (19) and the heat exchange cavity (2) are connected as a whole. The liquid nitrogen inlet pipe (19) is provided with a stop valve I (20), and the liquid nitrogen outlet pipe (5) is provided with a stop valve II (22).

6. A freezing interception device according to claim 5, characterized in that: The liquid nitrogen outlet (5) is provided with a liquid nitrogen observation port (21), and the liquid nitrogen observation port (21) is funnel-shaped.

7. A freezing interception device according to any one of claims 1 to 6, characterized in that: A heat-conducting material is filled between the inner wall of the liquid feed pipe (3) and the outer wall of the pipe passing through the inner side of the liquid feed pipe (3).

8. A testing device for a freezing interception device, characterized in that: The inspection and detection device comprises a freezing interception device as described in any one of claims 1 to 7, including a pressurized pipe II (23), a liquid addition port (26), a simulation pipe (31), a pressure gauge (25), a discharge elbow (32) and a liquid tank (37), wherein the pressurized pipe I (12) and the pressurized pipe II (23) share a nitrogen bottle (11), the pressurized pipe I (12) and the control valve I (13) form a branch leading to the liquid nitrogen barrel (14), the pressurized pipe II (23) and the control valve II (24) form a branch leading to the inspection and detection device, the pressurized pipe II (23) is provided with a control valve II (24), and one end of the pressurized pipe II (23) is connected to the nitrogen bottle (11). 1), and the other end is connected to the simulation tube (31), the lower end of the simulation tube (31) is connected to a discharge elbow (32), the pressure tube II (23) is provided with a stop valve III (28) near the end, a liquid addition port (26) is provided between the pressure gauge (25) and the stop valve III (28), the liquid addition port (26) is provided with a stop valve IV (29), the liquid addition port (26) is provided with a feeding funnel (27), the discharge elbow (32) includes a horizontal section I (33), a vertical section I (34), a horizontal section II (35) and a vertical section II (36) in sequence along the liquid flow direction, and a liquid tank (37) is provided at the end of the discharge elbow (32).

9. The inspection and detection device for a freezing interception device according to claim 8, characterized in that: A quick connector (30) is provided between the simulation tube (31) and the pressurized tube II (23), and a quick connector (30) is provided between the simulation tube (31) and the discharge elbow (32). The upper and lower ends of the simulation tube (31) extend out of the upper and lower ends of the liquid feed tube (3).

10. The inspection and testing device for a freezing interception device according to claim 9, characterized in that: The upper end of the vertical section I (34) of the discharge elbow (32) is higher than the upper end of the liquid feed pipe (3).

Images