A fully enclosed expanded sand fluid filling system and filling method thereof

Abstract

The present invention discloses a fully enclosed expansive sand fluid filling system, comprising an expansive sand storage device, a cryogenic container, and a vacuum pumping device. The present invention also discloses a filling method for the fully enclosed expansive sand fluid filling system. The fully enclosed expansive sand fluid filling system and the filling method provided by the present invention adopt a fully enclosed structure, which can avoid the expansive sand from being directly exposed to the air during the filling process, and avoid the expansive sand dust from flying at the expansive sand filling operation site. At the same time, the expansive sand is dried and heated before entering the container, and the filling is carried out only after the sampling is qualified, which can improve the quality of the expansive sand and improve the thermal insulation effect of the expansive sand; based on the principle of the natural repose angle of fluid solid particles, pre-planning and scientific segmented implementation of the fully enclosed expansive sand filling can greatly reduce labor intensity; nitrogen gas with pressure adjusted according to predetermined requirements is used to apply a pressing force to the expansive sand filled to a certain thickness, and the pressing force is soft and uniform, which can effectively avoid mechanical crushing of the expansive sand during the filling process, and will not form accumulation cavities.

Description

Technical Field

[0001] The invention relates to a fully enclosed expanded sand fluid filling system and a filling method thereof, belonging to the technical field of cryogenic pressure vessels. Background Art

[0002] The modern industrial gas and new energy industries make extensive use of vacuum-insulated cryogenic pressure vessels. Vacuum powder insulation, also known as vacuum expanded sand, is commonly used for cryogenic pressure vessel insulation. This "powder" consists of perlite particles, also known as expanded pearlescent sand (hereinafter referred to as expanded sand), which expand at high temperatures. These hollow, spherical particles, with a particle size of 1-2 mm, are used as insulation for cryogenic vessels. Its low thermal conductivity significantly reduces heat radiation and heat transfer between the inner and outer containers of the cryogenic vessel, allowing for the long-term storage of cryogenic liquids (liquid nitrogen, liquid oxygen, and liquid argon) within the inner container. This type of insulation is highly favored by the market and users for its economical nature, acceptable insulation performance for small and medium-sized vessels, and its ability to maintain a certain level of insulation capacity even in the event of vacuum anomalies, significantly preventing secondary hazards.

[0003] Cryogenic container market for large and 500m 3 The demand for the above-mentioned super-large containers is constantly increasing. The existing small-scale workshop-style expanded sand filling mode is difficult to control the quality of the expanded sand filling, the expanded sand particles are obviously damaged, the expanded sand filling process is seriously polluted by the air, the stacking density of the expanded sand in the insulation interlayer of the container is uncontrollable, the expanded sand filling efficiency is low, the labor intensity is high, and SiO2 dust is flying at the expanded sand filling site, which is harmful to personnel health. Faced with large and super-large cryogenic containers, the expanded sand filling operation is very difficult and can no longer meet the needs of its expanded sand filling operation process. It is necessary to fundamentally reform the expanded sand filling method, process flow and control method.

[0004] The existing sand filling technology and method is to fill the sand from small containers, such as 5~50m 3 The expanded sand filling process used in containers is an inherited and traditional method. The facilities are simple and the methods are primitive. Bags or boxes of expanded sand are poured into the sand inlet and stirred with a rod-shaped tool to push the sand to fill the container interlayer. Some improvements include placing the expanded sand box at a higher location or turning on a vacuum pump while expanding the sand. This method is used on containers of a few cubic meters or dozens of cubic meters, and it has some effect on reducing labor intensity. However, existing expanded sand filling technology is not suitable for effectively improving the quality of expanded sand filling, improving the bulking density of expanded sand, maintaining the integrity of expanded sand particles, completely changing the working environment of expanded sand filling, and effectively improving the effectiveness of expanded sand filling, especially in terms of the practical possibility of using expanded sand insulation in large and ultra-large containers.

[0005] Specifically, the defects and deficiencies in the existing technology mainly include the following aspects: 1. The expanded sand is not properly pretreated, or the quality of the expanded sand material is not tested before it is poured into the container interlayer, and the expanded sand is directly exposed to the air during the filling process. During the expanded sand filling process, the expanded sand is exposed to the air and is in close contact with the air. The surface of the expanded sand particles is rough, and the expanded sand particles themselves are like popcorn, with a rough surface that can absorb a large amount of water and air. Expanded sand with humidity and temperature that do not meet the requirements will greatly increase the time for vacuuming in the manufacture of cryogenic containers, or will significantly reduce the long-term thermal insulation effect of the expanded sand, that is, reduce the thermal insulation performance of the cryogenic container. 2. The bulking density of the expanded sand filled into the insulating interlayer is uncontrollable. Bags or boxes of expanded sand are poured into the expanded sand ports by gravity, and the operators use long sticks to stir the expanded sand and push it to all directions and locations of the interlayer. There are very few expanded sand ports and vacuum ports. The usual configuration is 1~2 expanded sand ports and 1 vacuum port. The number and position of these "process ports" have not been specially designed and planned, resulting in large differences in the accumulation state and position of the expanded sand. The vacuum port has little inducing and attracting effect on the accumulation state of the expanded sand. The accumulation state of the expanded sand in the interlayer is uncontrollable, and the bulking density of the expanded sand is also uncontrollable. Uneven bulking density or voids are unavoidable. It is conditional for the expanded sand to play an insulating role in the interlayer. The bulking density of the expanded sand reaches 120~130Kg / m 3 The most appropriate method is to use a stacking density that is too high, that is, stacking too tightly or too loosely, which will increase the thermal conductivity of the expanded sand and the instability of the stacking state, affecting the ability of the container's insulation layer to block heat transfer. 3. In existing expanded sand filling methods, the flow of expanded sand cannot be effectively controlled during the process of filling the interlayer from the expanded sand port. Manual mechanical sand stirring and poking methods damage the integrity of the expanded sand particles. The mechanical stirring force of stick-like tools is used to guide the expanded sand. Relying on repeated and strong stirring, the expanded sand is pushed to various parts of the interlayer. During the mechanical stirring of the expanded sand, the integrity of the expanded sand particle size is greatly damaged. Moreover, the planning of the sand expansion area and the setting of the positions of the sand expansion ports and vacuum ports were not designed and planned in accordance with the "principle of the angle of repose of solid particle flow". Moreover, no matter how large the volume of the cryogenic container is, there are usually very few sand expansion ports and vacuum ports. That is, the distance for delivering sand by sticks will be very large. Even if the vacuum pump is started to assist, the sand expansion port and the vacuum port are far apart and the configuration is not matched. The induction effect of vacuuming is very small. As a result, the bulk density of the sand and the integrity of the particles cannot be effectively controlled, and it is difficult to obtain satisfactory thermal insulation performance. 4. The existing sand expansion filling method is labor-intensive, inefficient, and the operating environment is harmful to health. The existing sand expansion filling method lacks effective filling tools and appropriate filling processes. It relies entirely on manual labor and is very labor-intensive. The existing process conditions are not suitable for 50m 3 The above is not suitable for large or super-large cryogenic containers. At the same time, the sand filling operation site produces flying sand dust, the chemical composition of which is SiO2

[0006] If the operator inhales the pollutants into his lungs, he will suffer from incurable lung disease. This working environment needs to be thoroughly improved as soon as possible. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a fully enclosed expanded sand fluid filling system and a filling method thereof, which can avoid the expanded sand being directly exposed to the air during the filling process and avoid the expanded sand dust flying at the expanded sand filling operation site; further, a fully enclosed expanded sand fluid filling system and a filling method thereof are provided, which dry and heat the expanded sand before entering the container, and fill it only after the sampling is qualified, which can improve the quality of the expanded sand and improve the insulation effect of the expanded sand; further, a fully enclosed expanded sand fluid filling system and a filling method thereof are provided. By cooperating with the filling port and vacuum interface on the outer shell through the expansion sand filling direction adjustment device, large containers can be filled in sections. According to the principle of the natural repose angle of fluid solid particles, pre-planning and scientific segmented implementation of fully enclosed expansion sand filling can greatly reduce labor intensity. Furthermore, a fully enclosed expansion sand fluid filling system and a filling method thereof are provided. Nitrogen gas with pressure adjusted according to predetermined requirements is used to apply a compacting force to the expansion sand filled to a certain thickness. The compacting force is soft and uniform, which can effectively avoid mechanical crushing of the expansion sand during the filling process and will not form accumulation voids.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0009] A fully enclosed expanded sand fluid filling system includes an expanded sand storage device, a cryogenic container and a vacuum pumping device. The cryogenic container includes an outer shell, an inner liner is provided in the outer shell, and the inner liner is connected to a pressure balancing device arranged outside the cryogenic container through a balancing pipeline. A sandwich layer for filling expanded sand is formed between the outer shell and the inner liner. A filling port is provided on one side of the outer shell, and the filling port is connected to the discharge port of the expanded sand storage device through an expanded sand output pipeline. A vacuum pumping interface is provided on the other side of the outer shell, and the vacuum pumping interface is connected to the air inlet of the vacuum pumping device through a vacuum pumping pipeline.

[0010] The expanded sand storage device includes an expanded sand tank, which is provided with a remote pressure gauge and a remote thermometer. A feed switch valve is provided on the feed pipeline of the expanded sand tank, and a dry nitrogen inlet valve and a nitrogen heater are provided on the air inlet pipeline of the expanded sand tank. The discharge port of the expanded sand tank is connected to a sand outlet pipe, and the sand outlet pipe is connected to the expanded sand output pipeline. The expanded sand output pipeline is provided with a blower, a remote flow meter, a dryer, a heater, a thermometer and an expanded sand main valve in sequence along the flow direction of the expanded sand. The expanded sand output pipeline is connected to a recovery tank through a recovery pipeline and is located between the thermometer and the expanded sand main valve, and is connected to a expanded sand sampling device through a sampling pipeline. A recovery valve is provided on the recovery pipeline, and a sampling valve is provided on the sampling pipeline. The air extraction pipeline of the recovery tank is connected in parallel to the vacuum extraction pipeline, and a vacuum valve is provided on the air extraction pipeline.

[0011] The number of the filling ports and vacuum interfaces on the shell is N, where N is an integer greater than or equal to 3. Several of the filling ports are connected in parallel to the expanded sand output pipeline through expanded sand branch pipelines, and the expanded sand branch pipelines are provided with expanded sand valves. The vacuum interfaces are connected in parallel to the vacuum pipeline through gas branch pipelines, and the gas branch pipelines are provided with vacuum valves. The filling ports and vacuum interfaces are distributed radially along the shell, and each vacuum interface corresponds one-to-one to each of the filling ports.

[0012] A sand filling direction adjustment device is provided on the outside of the filling port, and the sand filling direction adjustment device includes a sand gun, a corrugated regulator is connected to the sand gun, and an adjustable nozzle is connected to the corrugated regulator. An adjustment bracelet is provided on the side of the adjustable nozzle, and an annular protrusion for connecting to the sand branch pipeline is provided on the upper part of the adjustable nozzle. The lower end of the adjustable nozzle extends into the outer shell and is connected to an endoscope. The endoscope is electrically connected to an endoscopic video display arranged outside the cryogenic container through a signal line. The endoscope and the adjustment bracelet cooperate to properly control the filling direction.

[0013] It also includes a high-pressure gas storage device, the output end of the high-pressure gas storage device is connected to a high-pressure gas pipeline, the high-pressure gas pipeline is provided with a pressure gauge and a pressure regulating valve, the high-pressure gas pipeline is connected in parallel with several air inlets of high-pressure gas output branches, the air outlet of the high-pressure gas output branch is connected to the expanded sand branch pipeline, and the high-pressure gas output branch is provided with a pressure nitrogen valve.

[0014] The vacuum pump comprises a vacuum pump, the air inlet of the vacuum pump is connected to the air outlet of the vacuum pipeline, and a filter, a vacuum pressure gauge and a vacuum main valve are sequentially arranged on the vacuum pipeline along the gas flow direction.

[0015] A filling method for a fully enclosed expanded sand fluid filling system, characterized by comprising the following steps:

[0016] The expanded sand in the expanded sand storage device is dried and heated, and then the expanded sand is transferred to the expanded sand sampling device for testing. The recovery tank is then opened to recover the expanded sand. After the test is qualified, the interlayer is vacuumed by the vacuum device;

[0017] The interlayer is divided into sections with serial numbers, and the corresponding sand expansion valves and vacuum valves of each section are opened in sequence according to the sequence of the section numbers. With the cooperation of the blower and the vacuum pump, the sand in the sand storage device is filled into the interlayer sections in sequence;

[0018] During the process of filling the expanded sand in each section, keep the vacuum valve open at regular intervals, close the expanded sand valve corresponding to the section, and open the pressure nitrogen valve in parallel with the expanded sand valve.

[0019] The high-pressure gas storage device adjusts the nitrogen to an appropriate pressure through a pressure regulating valve to apply appropriate compression force to the expanded sand accumulation layer in the interlayer section.

[0020] During the section-wise expanded sand filling process, an endoscope is used to monitor the filling status of the expanded sand. When the endoscopic video display shows that the section is full of expanded sand, an intervention instruction is issued to the PLC to switch to the next section filling. The PLC controls the relevant switch valves to switch to the filling of the next section according to the set program.

[0021] Beneficial effects of the present invention:

[0022] 1. The present invention adopts a fully enclosed expanded sand fluid filling method to effectively prevent the expanded sand from being contaminated by the atmosphere. The expanded sand is dried and heated before entering the container to ensure the moisture content of the filled expanded sand. Filling is carried out only after sampling is qualified. The various performance indicators of the expanded sand filled into the container interlayer can be fully guaranteed. The entire expanded sand filling process is completed under fully enclosed conditions, without contact with the atmosphere, and is completely uncontaminated by moisture in the atmosphere, ensuring that the expanded sand has the best insulation material properties. The fully enclosed expanded sand controllable fluid filling mode ensures that the expanded sand is carried out at a controllable steady-state flow rate throughout the filling process, and is not damaged by external mechanical forces. The complete particle size of the expanded sand can be fully protected. The fully enclosed expanded sand fluid filling mode allows operators to completely avoid the environmental problem of working in a SiO2 harmful dust environment and avoid the harm of expanded sand dust to operators.

[0023] 2. Under controlled pneumatic pressure, the expanded sand achieves the desired uniform packing density within the interlayer, preventing the formation of sand voids and ensuring the sand's thermal insulation performance. By filling with fluidized sand at an appropriate flow rate, the bulk density is established under preset air pressure conditions, making the bulk density controllable. Nitrogen at an appropriate pressure is then applied to the sand, which has been filled to a certain thickness. This gentle and uniform pressure effectively prevents the sand from breaking during the filling process and prevents the formation of voids. This ensures that the bulk density meets the desired requirements and the sand's thermal insulation performance is as expected.

[0024] 3. Under the coordinated cooperation of the blower and the vacuum pump, the flowing expanded sand in the fully enclosed pipeline is guided by the visual information of the endoscope, and the direction of the sand blasting port is appropriately adjusted. During the filling process, when the accumulated expanded sand reaches a certain thickness, soft pneumatic pressure is used in batches to compact the accumulated sand layer in an orderly manner. For large or extra-large containers of different volumes, based on the principle of the natural repose angle of flowing solid particles, pre-planning and scientific segmented implementation of fully enclosed expanded sand filling are carried out, which greatly reduces labor intensity and effectively improves the filling quality of insulation materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a structural schematic diagram of a fully enclosed expanded sand fluid filling system of the present invention;

[0026] Figure 2 This is a schematic diagram of the fully enclosed expanded sand flow filling partitioning process of the present invention;

[0027] Figure 3 It is a structural schematic diagram of the device for adjusting the direction of expanding sand filling in the present invention.

[0028] The reference numerals in the figure are as follows: 101-remote pressure gauge; 102-remote thermometer; 103-air blower; 104-remote flowmeter; 105-dryer; 106-heater; 107-thermometer; 108-sand expansion main valve; 109-sampling valve; 100-sand expansion tank; 110-recovery valve; 111-recovery tank; 112-feed switch valve; 113-dry nitrogen inlet valve; 114-nitrogen heater; 115-sand outlet pipe; 116-sand expansion output pipeline; 200-shell; 201-inner liner; 202-interlayer; 204-filling port; 205-sand expansion valve; 206-pressure nitrogen valve; 207-pressure gauge; 208-pressure regulating valve; 210- High-pressure gas pipeline; 211- Inflating valve; 212- Vacuum gauge; 213- Vacuum interface; 214- Vacuum valve; 215- Vacuum pipeline; 216- Filter; 217- Vacuum pressure gauge; 218- Main vacuum valve; 219- Vacuum pump; 221- Vacuum valve; 300- Sand sampling device; 301- Bellows regulator; 302- Adjustable nozzle; 303- Adjustment bracelet; 304- Annular protrusion; 305- Endoscope; 306- Endoscopic video display; 307- Sand gun; 400- Pressure balancing device; 500- High-pressure gas storage device. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0030] like Figure 1 As shown, the present invention provides a fully enclosed fluidized sand filling system, comprising a sand storage device, a cryogenic container, and a vacuum pump 111. The cryogenic container comprises an outer shell 200, within which is housed an inner liner 201. An interlayer 202 for filling with sand is formed between the outer shell 200 and the inner liner 201. The inner liner 201 is connected to a pressure equalization device 400 located outside the cryogenic container via a balancing line. The inner liner of the cryogenic container must be equipped with a nitrogen line to maintain its internal pressure. When sand is being expanded in the interlayer 202, an inflation valve 211 must be opened to maintain a nitrogen pressure within the inner liner 201 suitable for the sand expansion process, thereby protecting the inner liner 201. The upper portion of the cryogenic container outer shell 200 is provided with a predetermined number of filling ports 204, depending on the container size. The distance between adjacent filling ports 204 is 3.5 to 4.5 meters, and the filling ports 204 at both ends of the container are located 2.0 to 2.5 meters from the end annular seam. The filling port 204 is connected to the discharge port of the expanded sand storage device through the expanded sand output pipeline 116. A vacuum interface 213 is provided on the other side of the shell 200, and the vacuum interface 213 is connected to the air inlet of the vacuum device through the vacuum pipeline 215.

[0031] The expanded sand storage device includes an expanded sand tank 100. The expanded sand used in the cryogenic container is stored in the expanded sand tank 100, which has a volume at least twice the total volume of the cryogenic container's interlayer. The expanded sand tank 100 is equipped with a remote pressure gauge 101 and a remote thermometer 102. The expanded sand storage device's feed pipeline is equipped with a feed on-off valve 112. The nitrogen inlet pipeline is equipped with a dry nitrogen inlet valve 113 and a nitrogen heater 114. The nitrogen inlet pipeline is used to maintain the set pressure in the expanded sand tank 100. The discharge port of the expanded sand storage device is connected to a sand outlet pipe 115, which is connected to an expanded sand output pipeline 116. Along the expanded sand flow path, an air blower 103, a remote flow meter 104, a dryer 105, a heater 106, a thermometer 107, and an expanded sand main valve 108 are sequentially arranged on the expanded sand output pipeline 116. The expanded sand output pipeline 116, located between the thermometer 107 and the expanded sand main valve 108, is connected to a recovery tank 111 via a recovery pipeline. Furthermore, the expanded sand sampling device 300 is connected via a sampling pipeline. The recovery pipeline is equipped with a recovery valve 110 and a sampling valve 109. The air extraction pipeline of the recovery tank 111 is connected in parallel to the vacuum pumping pipeline 215. Before the expanded sand reaches the expanded sand pipe 116, it must undergo pretreatment and be sampled and tested for its performance parameters. The moisture content of the expanded sand should be ≤0.3%, and the temperature of the thermometer 107 should be 110°C. A main sand valve 108 is provided at the front end of the sand expansion pipe 116. When the sampling results at the sampling valve 109 do not meet the design requirements, the sand enters the recovery tank 111 through the recovery valve 110. When the sampling index meets the predetermined requirements, the recovery valve 110 is closed, and the sand filling valve 108 is in a ready-to-open state, completing the sand pretreatment process before the sand expansion. At this time, the sand expansion valves 205 configured on the sand inlet pipes above the sand expansion ports 204 provided on the upper part of the cryogenic container are all in a closed state.

[0032] The number of filling ports 204 and vacuum interfaces 213 on the shell 200 is N, where N is an integer greater than or equal to 3. Several filling ports 204 are connected in parallel to the sand output pipeline 116 through sand output branches, and sand valves 205 are provided on the sand branch pipelines. The vacuum interfaces 213 are connected in parallel to the vacuum pipeline 215 through gas output branches, and vacuum valves 214 are provided on the gas branch pipelines. The filling ports 204 and vacuum interfaces 213 are distributed radially along the shell 200, and each vacuum interface 213 corresponds to each filling port 204. When the sand sampling is qualified and the container interlayer vacuum reaches the predetermined index, the sand expansion operation procedure is entered. Figure 2As shown, the filling of the interlayer of the container with expanded sand follows the requirements of the relevant process procedure documents. This case is divided into sections, from sequence number 1 to sequence number 7, and carried out in an orderly manner. The section division is based on the "natural repose angle law of solid fluid particles" and the size of the cryogenic container, that is, the size of the interlayer space. The section division is scientifically and rationally planned and designed, and the section length dimensions and the location of the expansion port and vacuum port in each section are set. During filling, the air flow rate of the blower 103 and the exhaust rate of the vacuum pump 219 are set based on actual test results. They must be coordinated to allow the expanded sand to enter the interlayer space in a steady-state fluid state and accumulate in the corresponding area under the suction induction of the vacuum pump.

[0033] like Figure 3 As shown, a device for adjusting the direction of sand filling is provided outside the filling port 204. The device includes a sand gun 307 connected to a bellows regulator 301, which is connected to an adjustable spout 302. An adjustment bracelet 303 is provided on the side of the adjustable spout 302. An annular protrusion 304 is provided on the top of the adjustable spout 302 for connecting to a branch pipe for sand filling. The lower end of the adjustable spout 302 extends into the housing 200 and is connected to an endoscope 305. The endoscope 305 is equipped with a spotlight and has an adjustable viewing distance. The endoscope 305 is electrically connected to an endoscopic video display 306 located outside the cryogenic container via a signal line. During the sand expansion process, endoscope 305 transmits image information, and the sand accumulation status is observed on the wired endoscopic video 306. The adjustment bracelet 303 is used to manually adjust the direction of the sand flow from the nozzle, effectively improving the quality and efficiency of the sand expansion. Under manual intervention, when a section of sand is filled, the PLC is instructed to switch to the next section.

[0034] The present invention also includes a high-pressure gas storage device 500, the output end of which is connected to a high-pressure gas pipeline 210. The high-pressure gas pipeline 210 is equipped with a pressure gauge 207 and a pressure regulating valve 208. The pressure regulating valve 208 adjusts the nitrogen pressure to 0.1 MPa. The high-pressure gas pipeline 210 is connected in parallel to the air inlets of several high-pressure gas output branches. The air outlets of the high-pressure gas output branches are connected to the sand expansion branch pipeline, which is equipped with a pressure nitrogen valve 206. According to the sand expansion process, during the segmented filling process, after the sand has been filled and accumulated for a period of time, N2 gas adjusted to an appropriate pressure is used to apply a compacting force to the sand accumulation layer to achieve the desired bulk density. This can also eliminate voids in the sand accumulation layer. According to the operating procedure, when it is the turn of the sand expansion port 204 to be filled with sand and the N2 gas is used to apply a compacting force, only the pressure nitrogen valve 206 on the corresponding N2 gas distribution line is opened, and the other pressure nitrogen valves 206 are closed.

[0035] The vacuuming device in the present invention includes a vacuum pump 219, the air inlet of which is connected to the air outlet of a vacuum line 215. A filter 216, a vacuum pressure gauge 217, and a vacuum main valve 218 are positioned along the gas flow path on the vacuum line 215. The air extraction line of the recovery tank 111 is connected to the vacuum line 215 between the vacuum pressure gauge 217 and the vacuum main valve 218, and a vacuum valve 221 is positioned on the air extraction line. The interlayer is vacuumed before entering the expanded sand pretreatment process. At the lower portion of the cryogenic container, corresponding to the filling port, are located a corresponding number of vacuum ports 213 equipped with sand filters, as well as vacuum branch lines. Each vacuum port is connected to the vacuum main pipe 215 via a vacuum valve 214 and branch lines. The vacuum main pipe is equipped with a filter 216, a vacuum pressure gauge 217, a vacuum main valve 218, and a vacuum pump 219. When the interlayer enters the vacuum pretreatment procedure, the vacuum pump 219 is turned on and all the vacuum valves 214 are opened. When the interlayer vacuum gauge 212 reaches the preset vacuum degree of 25kPa, all the vacuum valves 214 are closed, and the vacuum system completes the pre-sand expansion preparation procedure.

[0036] The following is the actual operating procedure flow of the filling method of a fully enclosed expanded sand fluid filling system of the present invention.

[0037] 1. Preparation procedures before expanding sand filling:

[0038] Sand pretreatment procedure. Open dry nitrogen inlet valve 113, maintain the sand tank pressure gauge 101 at 0.15 MPa, and turn on the sand tank nitrogen heater 114. When the temperature of the remote thermometer 102 reaches 80°C, start the blower, and set the flow rate of flow meter 104 to 1.2 m³ / min. Start the adsorption dryer 105 and heater 106. Manually sample the pretreated sand. After testing the sand sample, if the moisture content is ≤0.3% and the thermometer 107 reaches 110°C, the sand pretreatment procedure is complete. Before entering the sand filling procedure, open the recovery valve 110 at the recovery tank entrance, and the sand tank 111 recovers the sand.

[0039] Interlayer vacuum pretreatment procedure: Close all sand expansion valves 205; open all vacuum valves 214 and the main vacuum valve 218; start the vacuum pump 219; when the vacuum level of the interlayer vacuum gauge 212 reaches 25 kPa, close all vacuum valves except the vacuum valve 214 in the first sand expansion area; and keep the vacuum pump 219 running.

[0040] 2. Input control parameters to the PLC: pressure gauge 101: 0.15 MPa, remote thermometer 102: 80°C, flowmeter 104: 1.2 m³ / min, thermometer 107: 110°C, and sand sampling: moisture content ≤ 0.3%. Interlayer vacuum and pressure gauge parameters: vacuum gauge 212: 25 kPa, and pressure gauge 207: 0.1 MPa.

[0041] 3. Sand filling control procedure. Close the recovery valve 110; open the main sand filling valve 116; close each pressure nitrogen valve 206; close the vacuum valve 214 corresponding to each vacuum port; divide the interlayer into sections according to the requirements of the sand filling process document, from sequence number (1) to sequence number (7), and implement sand filling in the order of the section sequence number; when filling the section with sequence number (1), open the corresponding vacuum valve 214 and the corresponding sand filling port valve 205.

[0042] 4. Pneumatic compaction procedure for the sand accumulation layer. During the filling process of the sand filling section (1), every 5 minutes, keep the vacuum valve 214 open, close the sand filling port valve 205, and open the corresponding pressure nitrogen valve 206-1 below the sand filling port valve 205. The nitrogen valve 206 is opened for 1 minute and then closed immediately. Open all the vacuum valves 214, and wait until the vacuum degree of the vacuum gauge 212 reaches 25kPa. Except for the vacuum valve 214 corresponding to section (1), which remains open, the remaining vacuum valves 214 are closed. For the area with serial number (1), continue to fill the remaining sections according to the filling procedure.

[0043] 5. Manual intervention in program control. When the endoscope 305 is used manually and the endoscopic video display 306 shows that the (1) section is full of expanded sand, an intervention instruction is issued to the PLC to switch to the next section (2) filling. The PLC switches to the filling of the next section according to the set program until the entire interlayer 202 is completely filled.

[0044] Before implementing the fully enclosed sand filling process and control method disclosed in the present invention, a "fully enclosed sand filling operation process and regulations" should be compiled. The valves and instruments configured in the entire process are remotely controlled, and the relevant information is transmitted to the central control console, which monitors and controls the entire system. 3 The following cryogenic containers can be operated manually according to the operating process and regulations and the process documents, or the control program and control parameters can be input into the PLC controller to implement program-controlled automatic operation. 3 Above, especially 200m 3 Up to 1000m 3Large and ultra-large cryogenic vessels of 1000 tons and larger utilize PLC program controllers for program-controlled automatic operation, significantly improving work efficiency, effectively reducing labor intensity, and enhancing the quality of sand filling in large vessels, effectively improving thermal insulation. The fully enclosed sand filling system is monitored and manually operated by a central control console equipped with a programmable controller (PLC). Once the central console issues a sand filling start command to the PLC, the PLC will complete the automatic operation under manual supervision according to the preset program and relevant parameter requirements.

[0045] The present invention provides a fully enclosed fluidized sand filling system and a filling method thereof. The fluidized sand filling system is fully enclosed, and the sand flows slowly and orderly in the system in a fluid state. Utilizing the combined effects of fan delivery and vacuum pump suction, coupled with the regional division of the sand filling area and the scientific and reasonable planning and arrangement of the sand inlets and vacuum outlets, an expanded sand flow with controllable pressure and flow rate is effectively formed, achieving the desired expanded sand bulk density. The quality and effectiveness of the expanded sand filling are guaranteed, ensuring that the expanded sand filled into the container interlayer meets the set temperature and dryness, has a complete particle size, and achieves the ideal bulk density. The operator no longer has to work in an environment of expanded sand dust. The entire process is carried out in accordance with the process operating procedures, monitoring the pressure, temperature, and flow rate of the expanded sand in the pipeline system, and correctly operating each valve system in different steps to complete the expanded sand filling in an orderly and efficient manner. The filling system uses an appropriately caliber expanded sand delivery pipeline and a full-bore control ball valve to ensure that the particle integrity of the expanded sand reaches over 95%.

[0046] The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A fully enclosed expanded sand fluid filling system, characterized by: The invention comprises an expanded sand storage device, a cryogenic container and a vacuum pumping device, wherein the cryogenic container comprises an outer shell (200), an inner liner (201) is provided in the outer shell (200), the inner liner (201) is connected to a pressure balancing device (400) arranged outside the cryogenic container via a balancing pipeline, an interlayer (202) for filling expanded sand is formed between the outer shell (200) and the inner liner (201), a filling port (204) is provided on one side of the outer shell (200), the filling port (204) is connected to the discharge port of the expanded sand storage device via an expanded sand output pipeline (116), a vacuum pumping interface (213) is provided on the other side of the outer shell (200), the vacuum pumping interface (213) is connected to the air inlet of the vacuum pumping device via a vacuum pumping pipeline (215), and a plurality of the filling ports (204) are connected in parallel at the outer shell (200) via expanded sand branch pipelines. The sand output pipeline (116) is provided with a sand valve (205) on the sand branch pipeline, and a sand filling direction adjustment device is provided on the outside of the filling port (204). The sand filling direction adjustment device includes a sand gun (307), a corrugated regulator (301) is connected to the sand gun (307), and an adjustable nozzle (302) is connected to the corrugated regulator (301). The adjustable nozzle (302) is provided with an adjustment bracelet (303) on the side, and an annular protrusion (304) for connecting to the sand branch pipeline is provided on the upper part of the adjustable nozzle (302). The lower end of the adjustable nozzle (302) extends into the housing (200) and is connected to an endoscope (305). The endoscope (305) is electrically connected to an endoscopic video display (306) provided outside the cryogenic container through a signal line.

2. The fully enclosed expanded sand fluid filling system according to claim 1, characterized in that: The expanded sand storage device comprises an expanded sand tank (100), the expanded sand tank (100) is provided with a remote pressure gauge (101) and a remote thermometer (102), a feed switch valve (112) is provided on the feed pipeline of the expanded sand tank (100), a dry nitrogen inlet valve (113) and a nitrogen heater (114) are provided on the air inlet pipeline of the expanded sand tank (100), a discharge port of the expanded sand tank (100) is connected to a sand outlet pipe (115), the sand outlet pipe (115) is connected to the expanded sand output pipe (116), and the expanded sand output pipe (116) is provided with a blower (103), a remote pressure gauge (101) and a remote thermometer (102) in sequence along the flow direction of the expanded sand. A flow meter (104), a dryer (105), a heater (106), a thermometer (107) and a main valve for expanding sand (108); the expanding sand output pipeline (116) is connected to a recovery tank (111) via a recovery pipeline and is located between the thermometer (107) and the main valve for expanding sand (108); and is connected to an expanding sand sampling device (300) via a sampling pipeline; the recovery pipeline is provided with a recovery valve (110); the sampling pipeline is provided with a sampling valve (109); the air extraction pipeline of the recovery tank (111) is connected in parallel to the vacuum extraction pipeline (215); and the air extraction pipeline is provided with a vacuum valve (221).

3. The fully enclosed expanded sand fluid filling system according to claim 2, characterized in that: The number of the filling ports (204) and the vacuum interfaces (213) on the housing (200) is N, where N is an integer greater than or equal to 3. The vacuum interfaces (213) are connected in parallel to the vacuum pipeline (215) via gas branch pipelines, and a vacuum valve (214) is provided on the gas branch pipeline. The filling ports (204) and the vacuum interfaces (213) are distributed radially along the housing (200), and each vacuum interface (213) corresponds to each filling port (204) one by one.

4. The fully enclosed expanded sand fluid filling system according to claim 3, characterized in that: The apparatus further comprises a high-pressure gas storage device (500), wherein the output end of the high-pressure gas storage device (500) is connected to a high-pressure gas pipeline (210), a pressure gauge (207) and a pressure regulating valve (208) are provided on the high-pressure gas pipeline (210), the high-pressure gas pipeline (210) is connected in parallel to the gas inlets of a plurality of high-pressure gas output branches, the gas outlets of the high-pressure gas output branches are connected to the expanded sand branch pipeline, and a pressure nitrogen valve (206) is provided on the high-pressure gas output branch.

5. The fully enclosed expanded sand fluid filling system according to claim 4, characterized in that: The vacuum pumping device comprises a vacuum pump (219), an air inlet of the vacuum pump (219) is connected to an air outlet of the vacuum pipeline (215), and a filter (216), a vacuum pressure gauge (217), and a vacuum main valve (218) are sequentially arranged on the vacuum pipeline (215) along the direction of gas flow.

6. A filling method for the fully enclosed expanded sand fluid filling system according to claim 5, characterized in that: The following steps are involved: Drying and heating the expanded sand in the expanded sand storage device, then transferring the expanded sand to the expanded sand sampling device (300) for testing, then opening the recovery tank (111) to recover the expanded sand, and after the test is qualified, vacuuming the interlayer (202) through the vacuum device; The interlayer (202) is divided into sections with serial numbers, and the sand expansion valves (205) and vacuum valves (214) corresponding to the sections are opened in sequence according to the sequence numbers, and the sand in the sand storage device is filled into the interlayer (202) sections in sequence with the cooperation of the air blower (103) and the vacuum pump (219); During the process of filling the expanded sand in each section, the vacuum valve (214) is kept open at regular intervals, the expanded sand valve (205) corresponding to the section is closed, and the pressure nitrogen valve (206) connected in parallel with the expanded sand valve (205) is opened. The high-pressure gas storage device (500) is adjusted to an appropriate pressure through the pressure regulating valve (208) to implement controllable air pressure compression on the expanded sand accumulation layer in the interlayer (202) section.

7. The filling method of the fully enclosed expanded sand fluid filling system according to claim 6, characterized in that: During the section expansion sand filling process, the endoscope (305) is used to monitor the expansion sand filling status. When the endoscope video display (306) shows that the section expansion sand is full, an intervention instruction is issued to the PLC to switch to the next section filling. The PLC controls the relevant switch valve to switch to the next section filling according to the set program.

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