Fluid delivery device and method of delivering fluid

Abstract

The invention discloses a fluid conveying device and a fluid conveying method.The fluid conveying device comprises a raw material storage tank containing fluid to be conveyed, a fluid pressurizing unit, a resistance flow limiting unit and a communicating pipeline, the fluid pressurizing unit comprises a flexible medium driving source, and the flexible medium driving source drives a flexible medium to be loaded to the fluid in the raw material storage tank at set pressure; the resistance current-limiting unit comprises multiple stages of resistance current-limiting subunits which are communicated in series, and each stage of resistance current-limiting subunit comprises one or more capillary tubes which are connected in parallel. According to the fluid conveying device, the flexible medium serves as driving force, impact of fluid on mechanical moving parts and mechanical sealing structures is reduced, and therefore the sealing effect, the sealing stability of long-term operation and the stability and continuity of fluid conveying are improved. And the range ratio can be improved, and the system complexity is reduced.

Description

Technical Field

[0001] This invention relates to the field of fluid transport technology, and more specifically to a fluid transport device and a method for transporting fluid. Background Technology

[0002] In the field of industrial production technology, especially in the field of chemical production, liquid transportation is a fundamental and important link. The selection of liquid transportation equipment generally follows the following principles: (1) The type and design performance of the equipment should meet the process parameters such as flow rate, pressure, and temperature of the liquid; (2) The equipment itself (and related components such as flow-through parts) should be compatible with the fluid medium being transported in order to avoid abnormal transportation caused by rapid corrosion and leakage, as well as the risk of leakage of toxic, harmful, flammable and explosive substances; (3) In terms of mechanics, the transportation equipment is required to have high reliability, and in terms of economy, the unit cost of transportation operation is required to be low.

[0003] Currently, most liquid conveying devices use pumps to transport liquids. Common pumps include diaphragm pumps and high-pressure dual (multi) cylinder plunger pumps (plunger pumps can be further divided into axial and radial types based on the arrangement and direction of their plungers). Figure 1 and Figure 2 As shown, both high-pressure plunger pumps 200 with different structural types are reciprocating positive displacement pumps. Within a fixed pump chamber, the piston 210 reciprocates at a certain amplitude, and the fluid is controlled to be transported by adjusting the frequency of the reciprocating motion. During the liquid transport process, each reciprocating motion of the piston 210 first draws the liquid into the pump body 220 and then discharges it from the pump body 220, thereby achieving quantitative liquid transport.

[0004] In such pump structures, to meet the demands of high-pressure environments, elastomers made of materials such as rubber, polytetrafluoroethylene (PTFE), or graphite are typically used as seals at the points where the liquid contacts the pump to prevent leakage. However, the frequent reciprocating motion of the plunger causes wear and deformation of the elastomer, leading to decreased sealing performance and slow, minute leaks. If the fluid being pumped contains a volatile solvent, the solid solute precipitated from the solution after evaporation will remain in the gap between the plunger and the sealing ring, accelerating the wear of the elastomer and further increasing the leakage rate, ultimately affecting the operational stability and safety of the entire process.

[0005] On the other hand, as positive displacement pumps, plunger pumps and diaphragm pumps, due to their working principle, exhibit fluctuations and discontinuities in the output fluid. Figure 2 Taking the high-pressure plunger pump shown as an example, due to the reciprocating motion of the piston, during operation, the piston first moves upward (e.g., Figure 2 (As shown in the left diagram), to draw fluid from the inlet into the pump body (this process is called suction); then, the piston moves downwards (as shown in the left diagram). Figure 2(See the diagram on the right) to illustrate the process of pumping fluid from the outlet (this process is called drainage). In this reciprocating process, the fluid is delivered intermittently at a relatively fixed flow rate each time, creating discontinuity; the pressure of the fluid is not constant during the suction and drainage phases, but fluctuates to some extent. In laboratory or industrial applications, especially when precise quantitative delivery of small flow rates is required, external buffers or multiple pumps connected in parallel with staggered phases are generally used to smooth out the fluctuations in liquid delivery and improve the accuracy of the delivered liquid flow rate; however, this not only increases the complexity of the system, but also increases the difficulty of later equipment maintenance and operating costs. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of poor sealing effect, large fluctuation and discontinuity of fluid in high-pressure fluid transportation in the prior art, and to provide a fluid transportation device and a method for transporting fluid.

[0007] The present invention solves the above-mentioned technical problems through the following technical solution:

[0008] A fluid transport device, the fluid transport device comprising:

[0009] A raw material storage tank containing the fluid to be transported;

[0010] A fluid pressurization unit includes a flexible medium driving source connected to the inlet end of the raw material storage tank. The flexible medium driving source is used to drive the flexible medium to load the fluid in the raw material storage tank at a set pressure to drive the fluid flow.

[0011] A resistance flow limiting unit is connected to the outlet end of the raw material storage tank. The resistance flow limiting unit includes multiple levels (e.g., 2-6 levels) of resistance flow limiting sub-units connected in series. Each level of the resistance flow limiting sub-unit includes one or more (e.g., 1-6) capillary tubes connected in parallel. The diameter of the capillary tube is smaller than the diameter of the input tube of the resistance flow limiting unit.

[0012] In this solution, the fluid delivery device, through the cooperation of a fluid pressurization unit and a resistance flow limiting unit, can achieve fluid delivery under high pressure conditions. Using a flexible medium as the driving force reduces the impact of the fluid on mechanical moving parts and the mechanical seal structure, thereby improving the sealing effect and long-term sealing stability, as well as the stability and continuity of fluid delivery. Especially for the delivery of small-flow-rate liquids prone to phase change, this fluid delivery device achieves precise control of the small flow rate. Using a flexible medium as the thrust reduces the penetration of the liquid into the mechanical seal components, thus preventing leakage and achieving long-term stable transmission. Specifically, the fluid delivery device generates high-pressure driving force through the fluid pressurization unit and uses a flexible medium to drive the fluid. Compared to existing technologies using mechanical actuation (such as a pump body driving fluid through a rigid piston), this avoids the wear of the sealing structure caused by frequent reciprocating motion of rigid actuating components, reduces the impact of the fluid on the delivery pipeline, and improves the sealing effect. The high-pressure fluid is driven through the aforementioned multi-stage resistance flow-limiting subunit. The small diameter of the multi-stage capillary tubes restricts the fluid flow, preventing uncontrolled rapid flow and reducing penetration and impact on the sealing structure. This also improves the stability and safety of the transported fluid, further enhancing the sealing effect and the stability and continuity of fluid transport. Furthermore, using capillary tubes as the transport medium increases the range ratio (the ratio between the maximum and minimum flow rates that the transport device can effectively deliver, reflecting its performance and applicability), allowing the fluid transport device to adapt to different fluid transport needs and providing a wide range of applications. The flow restriction through capillary tubes also achieves buffering, resulting in a pulse-free continuous flow output from the fluid transport device, eliminating the need for external buffers or other additional buffering equipment and reducing system complexity.

[0013] Preferably, the capillaries between the multiple levels of the resistance current-limiting sub-units are configured according to a first set rule, which is related to one or more of the material, shape, diameter, and length of the capillaries.

[0014] In this scheme, the capillaries between different levels of resistance flow limiting subunits are configured according to a set pattern (e.g., any one or a combination of four parameters: material, shape, pipe diameter, and length) to adapt to the sealing requirements under different fluid conditions. The fluid conditions include factors such as fluid type (e.g., fluid material and viscosity), flow rate, and delivery distance, which is beneficial to the sealing effect and has better adaptability.

[0015] Preferably, the different capillaries of the same level of the resistance current limiting subunit are configured according to a set second rule, which is related to one or more of the material, shape, diameter and length of the capillaries.

[0016] In this scheme, different capillaries in the same level of resistance flow limiting subunit are configured according to a set pattern (e.g., any one or a combination of four parameters: material, shape, pipe diameter, and length) to adapt to the sealing requirements under different fluid conditions. The distribution of fluid among different capillaries in the same level of resistance flow limiting subunit can also be adjusted, which is beneficial to the sealing effect and has better adaptability.

[0017] Preferably, the capillary is configured according to the following formula:

[0018] ;

[0019] in, Let μ be the pressure drop across the capillary tube of the nth stage, μ be the dynamic viscosity of the fluid, F be the flow rate of the fluid, and d be the pressure drop across the capillary tube of the nth stage. n L is the diameter of the capillary tube of the nth stage. n The length of the capillary in the nth stage; The constant value is set to 0.68.

[0020] In this solution, the above formula allows for the selection of a capillary tube with an appropriate diameter based on the target pressure drop and flow requirements, thereby avoiding any impact on the sealing effect and improving the conveying efficiency.

[0021] Preferably, the input pipe of the resistance flow limiting unit is provided with a flow regulating valve;

[0022] And / or, the connecting pipes between the multiple resistance flow limiting subunits are equipped with flow regulating valves.

[0023] In this solution, the total flow rate of fluid entering the resistance flow limiting unit and / or the flow rate of fluid entering different stages of resistance flow limiting subunits can be controlled by the flow regulating valve, which can avoid excessive flow rate or large fluctuations, thereby ensuring the sealing effect and the stability of fluid delivery.

[0024] Preferably, at least one or both ends of the multiple parallel capillary tubes of the first-level resistance current-limiting subunit are connected to a switching valve.

[0025] In this solution, switching valves can be used to switch between multiple capillaries to meet the delivery requirements of different fluids.

[0026] Preferably, the flexible medium is a gas.

[0027] The flexible medium driving source is a compressed high-pressure gas source; or, the flexible medium driving source includes a low-pressure storage tank containing gas and a pressurization device connected to the low-pressure storage tank, the pressurization device being used to pressurize the gas in the low-pressure storage tank.

[0028] In this solution, the fluid conveying device uses gas as a flexible medium, taking advantage of the gas's flexibility to reduce impact during the conveying process; compressed gas or low-pressure gas is pressurized to provide the power to drive the fluid, which can improve the fluid conveying distance, efficiency and stability.

[0029] Preferably, the fluid pressurization unit further includes a pressure stabilizing device, which is disposed on the connecting pipeline between the flexible medium driving source and the raw material storage tank, or the pressure stabilizing device is separately connected to the raw material storage tank;

[0030] The pressure stabilizing device is used to regulate the pressure of the flexible medium entering the raw material storage tank.

[0031] In this solution, the pressure stabilizing device can stabilize the pressure of the flexible medium, resulting in smoother fluid transport. Specifically, if the pressure stabilizing device is installed on the connecting pipeline between the flexible medium drive source and the raw material storage tank, it can regulate the pressure of the flexible medium. If the pressure stabilizing device is connected separately to the raw material storage tank, it can regulate the fluid pressure inside the raw material storage tank or the pressure of the flexible medium entering the raw material storage tank, making pressure regulation more direct and accurate.

[0032] Preferably, the pressure stabilizing device includes a back pressure valve connected to the raw material storage tank, the back pressure valve being used to control the pressure of the flexible medium inside the raw material storage tank.

[0033] In this solution, the pressure of the flexible medium in the raw material storage tank is controlled by a back pressure valve. Compared to other pressure stabilization methods, this pressure stabilization device, using a back pressure valve, is simpler and more effective.

[0034] Preferably, the fluid conveying device further includes a metering and monitoring control unit, which includes a flow meter and a control unit disposed on the output pipe of the resistance flow limiting unit. The flow meter is used to detect the flow rate of the fluid, and the control unit is electrically connected to the flow meter. The control unit is used to receive the flow signal fed back by the flow meter and control the driving force of the flexible medium driving source or adjust the flow rate of the flexible medium.

[0035] In this scheme, the fluid conveying device can provide feedback on the output fluid flow rate by installing a flow meter on the output pipe of the resistance flow limiting unit. When the flow rate decreases, the control unit can control the driving force of the flexible medium to increase the output fluid flow rate, or the control unit can adjust the flow rate of the flexible medium to replenish the flexible medium and maintain a continuous driving effect.

[0036] A method for conveying a fluid, the method using a fluid conveying device as described above, wherein the fluid is a liquid that readily undergoes phase change; preferably, the liquid is any one or a combination of liquid ammonia, isobutylene, butene, methanol, ethanol, diethyl ether, and ethyl acetate.

[0037] In this solution, the fluid transport method uses the aforementioned fluid transport device under high pressure conditions and a flexible medium as the driving force, which reduces the impact of the fluid on the mechanical moving parts and mechanical seal structure. In particular, for the transport of small-flow-rate liquids that are prone to phase change, it achieves precise flow control and reduces the leakage caused by the liquid's penetration into the mechanical seal components. This improves the sealing effect and the long-term sealing stability, as well as the stability and continuity of fluid transport.

[0038] The positive and progressive effects of this invention are as follows: Through the cooperation of a fluid pressurization unit and a resistance flow-limiting unit, this fluid conveying device and method can achieve fluid conveying under high pressure conditions. Furthermore, using a flexible medium as the driving force reduces the impact of the fluid on mechanical moving parts and mechanical seal structures, thereby improving the sealing effect and long-term sealing stability, as well as the stability and continuity of fluid conveying. Moreover, using a capillary tube as the conveying medium increases the range ratio, making the fluid conveying device adaptable to a wide range of applications. By limiting the flow rate through the capillary tube, buffering is achieved, resulting in a pulse-free continuous flow output from the fluid conveying device, eliminating the need for external buffers or other additional buffering devices and reducing system complexity. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of a high-pressure plunger pump in the prior art.

[0040] Figure 2 This is a schematic diagram of another high-pressure plunger pump in the prior art.

[0041] Figure 3 This is a schematic diagram of the fluid transport device according to Embodiment 1 of the present invention.

[0042] Figure 4 This is a schematic diagram of the connection structure of the resistance current limiting unit in Embodiment 1 of the present invention.

[0043] Explanation of reference numerals in the attached figures:

[0044] High-pressure plunger pump 200

[0045] Piston 210

[0046] Pump body 220

[0047] Fluid conveying device 100

[0048] Fluid pressurization unit 110

[0049] Flexible dielectric drive source 1

[0050] Resistance current limiting unit 11

[0051] Drag current limiting subunit 16

[0052] Capillary 17

[0053] Switching valve 18

[0054] Shut-off valves 4, 10, 14, 15

[0055] Pressure reducing valve 2

[0056] Pressure gauge 3

[0057] Solenoid valve 5

[0058] Control Unit 6

[0059] Safety valve 7

[0060] Back pressure valve 8

[0061] Raw material storage tank 9

[0062] Needle valve 12

[0063] Flow meter 13

[0064] Filter 19 Detailed Implementation

[0065] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0066] Example 1

[0067] like Figure 3 and Figure 4 As shown, this embodiment provides a fluid conveying device 100, which includes a raw material storage tank 9, a fluid pressurization unit 110, a resistance flow limiting unit 11, and pipelines connecting the various components. The raw material storage tank 9 contains the fluid to be conveyed; the fluid pressurization unit 110 includes a flexible medium driving source 1 connected to the inlet end of the raw material storage tank 9, which drives the flexible medium to load the fluid in the raw material storage tank 9 at a set pressure to drive the fluid flow; the resistance flow limiting unit 11 is connected to the outlet end of the raw material storage tank 9, and includes multiple series-connected resistance flow limiting sub-units 16, each of which includes one or more parallel capillary tubes 17, the diameter of which is smaller than the diameter of the input tube of the resistance flow limiting unit 11.

[0068] Specifically, in this embodiment, the flexible medium is an inert gas, and the flexible medium driving source 1 is a high-pressure gas cylinder containing high-pressure inert gas. A pressure reducing valve 2, a pressure gauge 3, and a shut-off valve 4 are also provided in the pipeline connecting the high-pressure gas cylinder and the raw material storage tank 9. A shut-off valve 15 is provided on the input pipeline of the raw material storage tank 9. The output pipeline of the raw material storage tank 9 is connected to the resistance flow limiting unit 11 via a shut-off valve 10, and the outlet of the resistance flow limiting unit 11 is connected to the material outlet via a needle valve 12 and a shut-off valve 14.

[0069] When the fluid conveying device 100 is started, the shut-off valve 4 is opened, and the fluid to be conveyed flows into the raw material storage tank 9 from the material inlet and through the shut-off valve 15. At the same time, the high-pressure gas cylinder is opened, and the high-pressure inert gas is released. The high pressure drives the inert gas into the raw material storage tank 9, and the pressure of the inert gas in the raw material storage tank 9 gradually rises. When the pressure reaches the set value, the shut-off valve 4 is closed, and the shut-off valve 10, needle valve 12, and shut-off valve 14 are opened in sequence. Under the action of the high-pressure inert gas, the fluid in the raw material storage tank 9 is driven into the resistance flow limiting unit 11, through the capillary tube 17 of the multi-stage resistance flow limiting subunit 16, and finally sent to the material outlet from the output pipeline and output from the material outlet. Among them, the pressure reducing valve 2 can adjust the pressure of the inert gas in the pipeline, the pressure gauge 3 can monitor the pressure of the inert gas, the shut-off valve 4 acts as the switch for the inert gas to enter the raw material storage tank 9, the shut-off valve 10 acts as the switch for the fluid to enter the resistance flow limiting unit 11, and the needle valve 12 can precisely control the small flow rate to achieve slow and stable liquid supply.

[0070] This fluid delivery device 100, through the cooperation of the fluid pressurization unit 110 and the resistance flow limiting unit 11, can achieve fluid delivery under high pressure conditions. Using a flexible medium as the driving force reduces the impact of the fluid on mechanical moving parts and the mechanical seal structure, thereby improving the sealing effect, long-term sealing stability, and the stability and continuity of fluid delivery. Especially for the delivery of small-flow-rate liquids prone to phase change, this fluid delivery device 100 achieves precise control of the small flow rate. Using a flexible medium as the thrust reduces the penetration of the liquid into the mechanical seal components, thus achieving long-term stable transmission. Specifically, the fluid delivery device 100 generates high-pressure driving force through the fluid pressurization unit 110 and uses a flexible medium to drive the fluid. Compared to existing technologies using mechanical actuation (such as a pump body driving fluid through a rigid piston), this avoids wear on the sealing structure caused by frequent reciprocating motion of rigid actuating parts, reduces the impact of the fluid on the delivery pipeline, and improves the sealing effect. The high-pressure fluid is driven through the multi-stage resistance flow-limiting subunit 16. The small diameter of the multi-stage capillary tubes 17 restricts the fluid flow, preventing uncontrolled rapid flow of the high-pressure fluid, reducing penetration and impact on the sealing structure, and improving the stability and safety of the transported fluid. This further enhances the sealing effect and the stability and continuity of fluid transport. Furthermore, using capillary tubes 17 as the transport carrier improves the range ratio (the ratio between the maximum and minimum flow rates that the transport device can effectively transport, reflecting its performance and applicability), enabling the fluid transport device 100 to adapt to different fluid transport needs and providing a wide range of applications. By limiting the flow through capillary tubes 17, buffering is achieved, resulting in a pulse-free continuous flow output from the fluid transport device 100, eliminating the need for external buffers or other additional buffering equipment and reducing system complexity.

[0071] It should be noted that, because during the transportation of liquids prone to phase change, even a slight leak can cause a phase change, resulting in significant sealing problems. The fluid transportation device 100 of this embodiment, driven by a flexible medium and with flow restriction by a resistance flow limiting unit, greatly reduces the pressure and impact of the liquid on the sealing structure, thereby improving the sealing effect. Therefore, it has significant technical effects on the transportation of small flow rates of liquids prone to phase change. However, the fluid transportation device 100 is not limited to liquids prone to phase change, nor is it limited to the flow rate; it can also be used to transport other fluids and increase the transportation flow rate.

[0072] Among them, such as Figure 4 As shown, in this embodiment, the resistance current limiting unit 11 includes three-stage resistance current limiting sub-units 16. Each stage of resistance current limiting sub-unit 16 includes two capillaries 17 connected in parallel. The capillaries 17 of the three-stage resistance current limiting sub-units 16 are represented by dashed lines, dotted lines, and dashed lines, as well as different shapes, to represent different types of capillaries 17.

[0073] In other embodiments, the capillary tubes 17 between different levels of resistance flow limiting subunits 16 can be configured according to a first rule based on the fluid type. This first rule reflects the configuration of the capillary tubes 17 between different levels of resistance flow limiting subunits 16, and is related to any one or a combination of four parameters: material, shape, diameter, and length of the capillary tubes 17. For example, depending on the pressure change of the fluid, the diameter of the capillary tubes 17 at different levels gradually decreases; alternatively, the diameter and length of the capillary tubes 17 at different levels can be changed simultaneously; or any other one or a combination of these four parameters can be changed. This configuration of the capillary tubes 17 between different levels of resistance flow limiting subunits 16 can adapt to the sealing requirements under different fluid conditions. These conditions include fluid type (e.g., fluid material, viscosity), flow rate, and delivery distance, thus improving sealing performance and providing better adaptability. For example, for some highly viscous fluids, the capillary tubes 17 at each level can be made of materials with low surface resistance, and the diameter of each level gradually decreases to accommodate the flow of highly viscous fluids.

[0074] Among them, such as Figure 4 As shown, in this embodiment, the two capillaries 17 of the same stage are made of the same material but have different lengths. The two ends of the two parallel capillaries 17 of each stage of the resistance flow limiting subunit 16 are connected to a switching valve 18. In use, the different capillaries 17 of the same stage are switched according to the set switching sequence to adapt to the delivery requirements of different fluids.

[0075] In other embodiments, similarly, different capillaries 17 of the same level of resistance current limiting subunit 16 can also be configured according to a second rule. The second rule reflects the configuration of different capillaries 17 of the same level of resistance current limiting subunit 16, and the setting of the second rule can also be related to any one or more of the four parameters of the capillary 17: material, shape, diameter, and length. For example, the first rule is that the diameter of the capillaries 17 of different levels gradually decreases, while the second rule is that different capillaries 17 of the same level change in shape according to a set rule.

[0076] The capillary tube 17 is configured according to the following formula:

[0077] ;

[0078] Let μ be the pressure drop across the nth stage capillary tube 17, μ be the dynamic viscosity of the fluid, F be the flow rate of the fluid, and d be the pressure drop across the capillary tube 17. n L is the diameter of the nth stage capillary tube 17. n The length of the nth stage capillary 17; The constant value is set to 0.68.

[0079] Using the above formula, a suitable capillary tube 17 with appropriate diameter can be selected based on the target pressure drop and flow rate requirements, thereby avoiding affecting the sealing effect and improving the conveying efficiency. Furthermore, as shown in the formula, since the fluid flow rate F in the capillary tube 17 is proportional to the fourth power of the capillary tube 17 diameter d, when the diameter of the capillary tube 17 differs from the diameter of the input pipe by a factor of 5, the range ratio of the fluid passing through the resistance flow limiting unit 11 is 625:1, where 625 is 5 to the power of 4. This range ratio means that the fluid conveying device 100 can convey a minimum flow rate of 1 unit of fluid and a maximum flow rate of 625 units of fluid. The flow rate is based on the actual flow rate that can be effectively measured. Therefore, the range ratio is the ratio between the maximum flow rate and the minimum flow rate that the fluid conveying device can effectively convey. The higher or lower this ratio, the better the conveying performance and applicable range of the fluid conveying device. The range ratio of this embodiment is much higher than that of the prior art (50~100:1), thus, under the same pressure conditions, the fluid conveying device 100 of this embodiment can convey a wider range of flow rates. Furthermore, by increasing the length of the capillary 17, the range of the measurement ratio can be further increased.

[0080] Therefore, the fluid conveying device 100 improves the range ratio by using the aforementioned resistance flow limiting unit 11 and the capillary tube 17 as the conveying carrier, enabling the device to adapt to different fluid conveying needs and has a wide range of applications; by connecting the capillary tube 17 with the switching valve 18, it can adapt to the rapid switching of various materials without modification.

[0081] In other embodiments, the number of stages of the resistance flow limiting unit 11 can be adjusted according to the different fluids being transported and the required transport effect; that is, the number of resistance flow limiting sub-units 16 can be increased or decreased. The number, material, length, and diameter of the capillaries 17 in the same stage of the resistance flow limiting sub-unit 16 can also be adjusted accordingly. In use, the flow pattern of fluid in the multiple capillaries 17 within the same stage of the resistance flow limiting sub-unit 16 can either pass through only one capillary 17, switching between different capillaries 17 of the same stage for transporting different fluids; or the fluid can be distributed among multiple capillaries 17 of the same stage. By combining different patterns, the sealing requirements under different fluid conditions can be adapted, and the distribution of fluid among different capillaries 17 in the same stage of the resistance flow limiting sub-unit 16 can be adjusted, thereby improving the sealing effect and providing better adaptability.

[0082] like Figure 4 As shown, in this embodiment, the input pipe of the resistance flow limiting unit 11 is equipped with a filter, which can filter impurities in the fluid and prevent impurities from clogging the capillary tube 17.

[0083] In other embodiments, to control the total flow rate entering the resistance flow limiting unit 11, a flow regulating valve may be provided on the input pipe of the resistance flow limiting unit 11. Alternatively, to regulate the flow rate of fluid entering different stages of the resistance flow limiting subunits 16, a flow regulating valve may be provided on the connecting pipe between the multi-stage resistance flow limiting subunits 16. The flow regulating valve can adjust the flow rate to avoid excessive flow or large fluctuations, thereby ensuring the sealing effect and the stability of fluid delivery.

[0084] As described above, the flexible medium in this embodiment is an inert gas, which reduces the impact during transportation by utilizing the gas's flexibility; the flexible medium drive source 1 is a high-pressure gas cylinder. However, the flexible medium is not limited to gas. In other embodiments, the flexible medium can also be other gases or other flexible media that do not mix with the fluid to be transported and can drive the fluid; the flexible medium drive source 1 can also adopt other devices that can pressurize the flexible medium. For example, the flexible medium drive source 1 includes a low-pressure storage tank containing gas and a pressurization device connected to the low-pressure storage tank. The pressurization device pressurizes the gas in the low-pressure storage tank, which can also pressurize the low-pressure gas, providing the power to drive the fluid, thereby improving the fluid transportation distance and efficiency.

[0085] The fluid pressurization unit 110 also includes a pressure stabilizing device, which can regulate the pressure of the flexible medium entering the raw material storage tank 9. In this case, the fluid pressurization unit 110 is also called a fluid pressurization and pressure stabilization unit.

[0086] The pressure stabilizing device comes in various forms, with correspondingly different connection and communication methods. It can be installed on the connecting pipeline between the flexible medium drive source 1 and the raw material storage tank 9, or it can be connected independently to the raw material storage tank 9. The fluid conveying device 100 can stabilize the pressure of the flexible medium through the pressure stabilizing device, making the fluid conveying smoother. If the pressure stabilizing device is installed on the connecting pipeline between the flexible medium drive source 1 and the raw material storage tank 9, the pressure stabilizing device can regulate the pressure of the flexible medium; if the pressure stabilizing device is connected independently to the raw material storage tank 9, the pressure stabilizing device can regulate the fluid pressure in the raw material storage tank 9 or regulate the pressure of the flexible medium entering the raw material storage tank 9, making the pressure stabilization and regulation more direct and accurate.

[0087] In this embodiment, the pressure stabilizing device includes a back pressure valve 8 connected to the raw material storage tank 9. The back pressure valve 8 can release gas when the inert gas pressure in the raw material storage tank 9 exceeds a set pressure value, thereby controlling the gas pressure within the raw material storage tank 9. Alternatively, it can close the gas discharge outlet when the inert gas pressure in the raw material storage tank 9 is below the set pressure value, thus maintaining the inert gas pressure within the target pressure range. For example, to drive fluid transport, the gas pressure in the raw material storage tank 9 typically needs to be at least 0.5 MPa higher than the downstream material outlet pressure. Before the target pressure is reached, the back pressure valve 8 remains closed. During fluid transport, if the inert gas pressure in the raw material storage tank 9 exceeds the set value, the back pressure valve 8 can be opened to release gas and maintain pressure stability. Compared to other pressure stabilizing methods, this pressure stabilizing device using the back pressure valve 8 is simpler and more effective.

[0088] In addition, the pressure stabilizing device in this embodiment may also include a safety valve 7 connected to the raw material storage tank 9, which can also play a certain role in stabilizing pressure. When the fluid pressure in the raw material storage tank 9 is close to or greater than the warning pressure, the gas in the raw material storage tank 9 can be partially or completely vented to regulate the gas pressure in the raw material storage tank 9 and ensure the safe operation of the equipment.

[0089] like Figure 3 As shown, to precisely control the fluid delivery, the fluid delivery device 100 in this embodiment also includes a metering and monitoring control unit. This unit includes a flow meter 13 mounted on the output pipe of the resistance flow limiting unit 11 and a control unit 6 electrically connected to the flow meter 13. The flow meter 13 detects the fluid flow rate, and the control unit 6 is a PLC programmable controller. When the flow rate is lower than a set value, the flow meter 13 feeds back the monitored flow signal to the PLC programmable controller, which then controls the opening and closing of the solenoid valve 5 to replenish gas into the raw material storage tank 9 in real time. When the pressure inside the raw material storage tank 9 is too high, excess gas can be discharged through the back pressure valve. In other embodiments, the metering and monitoring control unit can precisely control the pressure inside the raw material storage tank 9 by adjusting the flow rate of the inert gas, thus achieving stable delivery of the liquid raw material. In other embodiments, the PLC programmable controller can also directly control the output pressure of the high-pressure gas cylinder or control the driving force of other flexible media drive sources 1 to precisely control the pressure inside the raw material storage tank 9.

[0090] Example 2

[0091] This embodiment provides a method for transporting fluid using a fluid transport device 100 as described in Embodiment 1, wherein the fluid is a liquid that readily undergoes phase change. This readily phase-change liquid can be a low-boiling-point readily phase-change liquid; preferably, this readily phase-change liquid is any one or a combination of liquid ammonia, isobutylene, butene, methanol, ethanol, diethyl ether, and ethyl acetate.

[0092] Specifically, the method for conveying fluid includes the following steps:

[0093] S1. The flexible medium drive source 1 of the fluid pressurization unit 110 pressurizes the fluid to be transported in the raw material storage tank 9 through the flexible medium.

[0094] S2. The driving fluid passes through the multi-stage resistance flow limiting sub-units 16 of the resistance flow limiting unit 11 in sequence. When the fluid passes through each stage of the resistance flow limiting sub-unit 16, the driving fluid passes through one or more parallel capillary tubes 17.

[0095] This fluid transport method, using the fluid transport device 100 under high pressure and a flexible medium as the driving force, reduces the impact of the fluid on the mechanical moving parts and mechanical seal structure. Especially for the transport of small-flow-rate liquids that are prone to phase change, it achieves precise flow control and reduces the leakage caused by the liquid's penetration into the mechanical seal components. This improves the sealing effect and the long-term sealing stability, as well as the stability and continuity of fluid transport.

[0096] More preferably, the method for conveying the fluid may further include: using a pressure stabilizing device to regulate the pressure of the flexible medium entering the raw material storage tank. The pressure stabilizing device may include a back pressure valve 8 and a safety valve 7 connected to the raw material storage tank. This step stabilizes the pressure of the flexible medium in the raw material storage tank, resulting in smoother fluid delivery.

[0097] More preferably, the method for conveying fluid may further include:

[0098] Detect the flow rate of the fluid flowing out of the resistance flow limiting unit 11;

[0099] Based on the detected fluid flow rate, the driving force of the flexible medium drive source 1 or the flow rate of the flexible medium is controlled to adjust the pressure of the flexible medium on the fluid to be transported in the raw material storage tank 9.

[0100] This step allows for feedback on the output fluid flow rate. When the flow rate decreases, the driving force of the flexible medium can be controlled to increase the output fluid flow rate, or the flow rate of the flexible medium can be adjusted to replenish the flexible medium and maintain a continuous driving effect.

[0101] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A fluid delivery device, characterized by, The fluid delivery device comprises: a raw material storage tank containing fluid to be delivered; a fluid pressurizing unit comprising a flexible medium driving source connected to an inlet end of the raw material storage tank, the flexible medium driving source being used to drive a flexible medium to load fluid in the raw material storage tank at a set pressure to drive fluid flow; a resistance flow limiting unit connected to an outlet end of the raw material storage tank, the resistance flow limiting unit comprising multiple levels of resistance flow limiting sub-units connected in series, each level of the resistance flow limiting sub-units comprising one or more capillary tubes connected in parallel, the capillary tubes having a tube diameter smaller than that of an input tube of the resistance flow limiting unit.

2. The fluid delivery device of claim 1, wherein, The capillary tubes between multiple levels of the resistance flow limiting sub-units are configured in a set first rule related to one or more of material, shape, tube diameter, length of the capillary tubes; and / or, the capillary tubes of the same level of the resistance flow limiting sub-units are configured in a set second rule related to one or more of material, shape, tube diameter, length of the capillary tubes.

3. The fluid delivery device of claim 1, wherein, The capillary tubes are configured according to the following formula: ； wherein, Pn is the pressure drop on the capillary of the nth stage, μ is the dynamic viscosity of the fluid, F is the flow rate of the fluid, d n dn is the diameter of the capillary of the nth stage, L n Ln is the length of the capillary of the nth stage; K is a constant set at 0.

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4. The fluid delivery device of claim 3, wherein, The input tube of the resistance flow limiting unit is provided with a flow regulating valve; and / or, the connecting pipeline between multiple levels of the resistance flow limiting sub-units is provided with a flow regulating valve.

5. The fluid delivery device of claim 1, wherein, Any one end or both ends of multiple parallel capillary tubes of at least one level of the resistance flow limiting sub-units are connected with a switching valve.

6. The fluid delivery device of any one of claims 1-5, wherein, The flexible medium is gas, The flexible medium driving source is a compressed high-pressure gas source; or, the flexible medium driving source comprises a low-pressure storage tank containing gas and a pressure boosting device connected to the low-pressure storage tank, the pressure boosting device being used to boost the pressure of the gas in the low-pressure storage tank.

7. The fluid delivery device of claim 1, wherein, The fluid pressurizing unit further comprises a pressure stabilizing device provided on a connecting pipeline between the flexible medium driving source and the raw material storage tank, or the pressure stabilizing device is separately connected to the raw material storage tank; The pressure stabilizing device is used to adjust the pressure of the flexible medium entering the raw material storage tank.

8. The fluid delivery device according to claim 7, wherein The pressure stabilizing device comprises a back pressure valve connected to the raw material storage tank, the back pressure valve being used to control the pressure of the flexible medium in the raw material storage tank.

9. The fluid delivery device of claim 1, wherein, The fluid delivery device further comprises a metering monitoring control unit comprising a flow meter provided on an output tube of the resistance flow limiting unit and a control unit, the flow meter being used to detect the flow of fluid, the control unit being electrically connected to the flow meter, the control unit being used to receive the flow signal fed back by the flow meter and control the driving force of the flexible medium driving source or adjust the flow of the flexible medium.

10. A method of delivering a fluid, characterized by, The method for delivering fluid uses the fluid delivery device according to any one of claims 1-9 to deliver fluid, the fluid being a liquid that is easy to change phase; preferably, the liquid is any one or a combination of liquid ammonia, isobutene, butene, methanol, ethanol, diethyl ether, ethyl acetate.

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