Non-Newtonian fluid high-precision constant inlet pressure control system based on multistage regulation and control and control method thereof

Abstract

The invention discloses a non-Newtonian fluid high-precision constant inlet pressure control system based on multi-stage regulation and control and a control method thereof, belongs to the field of fluid mechanics and fluid control, and solves the problems that an existing pressure control method is insufficient in precision, lagged in response and poor in adaptability in non-Newtonian fluid application. The constant high-pressure gas source, the multi-stage pressure adjusting plate and the high-pressure liquid storage tank are sequentially communicated, and the multi-stage pressure adjusting plate comprises a high-pressure area and a low-pressure area. The multi-stage pressure regulation and micro pressure control technology is combined, high-precision steady-state regulation of the inlet pressure is achieved through graded regulation and control of low-pressure and high-pressure areas, and meanwhile the quick response capacity is achieved so as to meet the non-Newtonian fluid flowing requirements under different working conditions.

Description

Technical Field

[0001] The present invention relates to the technical fields of fluid mechanics and fluid control, and particularly to a high-precision constant inlet pressure control system for non-Newtonian fluids based on multi-level regulation and its control method. Background Art

[0002] In fluid control systems, the stability of the inlet pressure has an important impact on experimental accuracy, flow characteristic control, and engineering applications. The existing fluid inlet control methods are mainly divided into two types: flow control and pressure control. Flow control usually uses syringe pumps, hydraulic pistons, or mass flow meters to indirectly affect the inlet pressure by adjusting the fluid transport rate. However, this method has obvious limitations in the application of non-Newtonian fluids, especially it is difficult to maintain a stable inlet pressure for a long time and has a weak response to external pressure fluctuations. In contrast, the pressure control method directly acts on the inlet pressure and mainly relies on pressure reducing valves, backpressure modulators, or active feedback systems to maintain a constant pressure output. Although such methods can improve pressure stability, there are still problems such as insufficient accuracy, slow response speed, and poor adaptability in the non-Newtonian fluid flow environment, making it difficult to meet the requirements of high-precision regulation in experimental research and engineering applications.

[0003] Due to the shear dependence, viscoelasticity, and complex rheological properties of non-Newtonian fluids, it is difficult to achieve precise regulation with traditional pressure control methods. Most existing systems adopt a single-level regulation mode, which is only applicable to low-viscosity Newtonian fluids and cannot be optimized for the complex characteristics of non-Newtonian fluids. In experiments and applications of high-viscosity and highly elastic fluids, small fluctuations in the inlet pressure may lead to significant changes in the flow state, affecting experimental repeatability and data reliability. In addition, existing pressure control devices usually cannot perform high-precision micro-regulation under high-pressure conditions, limiting their application in the field of precision control. Summary of the Invention

[0004] The present invention proposes a high-precision constant inlet pressure control system for non-Newtonian fluids based on multi-level regulation and its control method. The system combines multi-level pressure regulation and micro-pressure control technologies, and through hierarchical regulation in the low-pressure and high-pressure regions, realizes high-precision steady-state regulation of the inlet pressure, and at the same time has a fast response ability to meet the non-Newtonian fluid flow requirements under different working conditions, thereby solving the problems of insufficient accuracy, response lag, and poor adaptability of existing pressure control methods in the application of non-Newtonian fluids.

[0005] A high-precision constant inlet pressure control system for non-Newtonian fluids based on multi-level regulation includes: a constant high-pressure gas source, a multi-level pressure regulating plate, and a high-pressure liquid storage tank. The constant high-pressure gas source, the multi-level pressure regulating plate, and the high-pressure liquid storage tank are connected in sequence. Among them, the multi-level pressure regulating plate includes a high-pressure area and a low-pressure area.

[0006] Further, a constant high-pressure gas source is used to output gas with a constant pressure to a multi-stage pressure regulating plate;

[0007] The multi-stage pressure regulating plate is used to output gas to a high-pressure liquid storage tank through multi-stage pressure regulation and control;

[0008] The high-pressure liquid storage tank is used to discharge the liquid with a constant pressure in the tank to a preset fluid experiment scenario through the gas transported by the multi-stage pressure regulating plate;

[0009] Further, the constant high-pressure gas source includes a high-pressure gas source and a first pressure reducing valve. One end of the first pressure reducing valve is communicated with the high-pressure gas source, and the other end is communicated with the inlet of the multi-stage pressure regulating plate.

[0010] Further, in the multi-stage pressure regulating plate,

[0011] The low-pressure area includes: a first start-stop valve, a second-stage low-pressure pressure reducing valve, a low-pressure pressure modulator, a low-pressure pressure gauge, and a second start-stop valve;

[0012] The high-pressure area includes: a third start-stop valve, a high-pressure pressure modulator, a high-pressure pressure gauge, and a fourth start-stop valve;

[0013] The multi-stage pressure regulating plate further includes a first pressure relief valve;

[0014] The outlet of the first pressure reducing valve is divided into two paths, which are respectively communicated with the first start-stop valve in the low-pressure area and the third start-stop valve in the high-pressure area. The first start-stop valve, the second-stage low-pressure pressure reducing valve, the low-pressure pressure modulator, the low-pressure pressure gauge, and the second start-stop valve are sequentially communicated. The third start-stop valve, the high-pressure pressure modulator, the high-pressure pressure gauge, and the fourth start-stop valve are sequentially communicated. The outlets of the second start-stop valve and the fourth start-stop valve are combined and jointly communicated with one end of the first pressure relief valve and the upper end of the high-pressure liquid storage tank. The other end of the first pressure relief valve is communicated with the atmosphere.

[0015] Further, the high-pressure liquid storage tank includes a second pressure relief valve, a liquid level gauge, a cover plate, a tank body, and an outlet start-stop valve. The cover plate and the upper edge of the tank body are provided with corresponding threaded holes. The cover plate, the sealing ring, and the tank body are screwed together by screws through the threaded holes from top to bottom to achieve a sealed connection. A second pressure relief valve with one end communicated with the inside of the tank body and the other end communicated with the atmosphere is arranged on the cover plate. The liquid level gauge is tubular and installed outside the tank body, and the upper and lower ends are respectively communicated with the upper and lower spaces inside the tank body. An outlet start-stop valve is arranged at the bottom outlet of the tank body.

[0016] A control method for a non-Newtonian fluid high-precision constant inlet pressure control system based on multi-stage regulation, based on the above-mentioned non-Newtonian fluid high-precision constant inlet pressure control system based on multi-stage regulation, the control method includes a constant pressure mode, a variable pressure mode, and a pressure relief mode, wherein,

[0017] The constant pressure mode includes the following steps:

[0018] S1. Close the outlet start-stop valve and install the liquid level gauge;

[0019] S2. Place the configured non-Newtonian fluid into the tank body;

[0020] S3. Place a sealing ring along the upper edge of the tank body, cover the cover plate, and assemble and seal the tank body and the cover plate by tightening the screws;

[0021] S4. Connect the first-stage pressure reducing valve to the outlet of the high-pressure gas source and the inlet of the multi-stage pressure regulating plate;

[0022] S5. Ensure that the first start-stop valve, the second start-stop valve, the third start-stop valve, and the fourth start-stop valve are closed, the low-pressure pressure modulator and the high-pressure pressure modulator are in the flow-stop state, and the first pressure relief valve and the second pressure relief valve are closed;

[0023] S6. Open the high-pressure gas source switch to the maximum and the first-stage pressure reducing valve in sequence, and select the low-pressure area or the high-pressure area according to the final outlet pressure;

[0024] S7. If the low-pressure area is selected, open the first start-stop valve, adjust the second-stage low-pressure pressure reducing valve to the appropriate pressure outlet, or open the third start-stop valve;

[0025] S8. Adjust the low-pressure pressure modulator or the high-pressure pressure modulator until the low-pressure pressure gauge or the high-pressure pressure gauge reaches the expected pressure value;

[0026] S9. Open the second start-stop valve or the fourth start-stop valve and wait for the low-pressure pressure modulator or the high-pressure pressure modulator to stably drop back to the expected pressure value;

[0027] S10. Open the outlet start-stop valve and stably discharge the non-Newtonian fluid;

[0028] The constant pressure mode includes the following steps:

[0029] S11. On the basis of S1 - S10, close the second start-stop valve or the fourth start-stop valve;

[0030] S12. Fine-tune the low-pressure pressure modulator or the high-pressure pressure modulator to make the low-pressure pressure gauge or the high-pressure pressure gauge change to a new expected pressure value;

[0031] S13. Open the second start-stop valve or the fourth start-stop valve;

[0032] The pressure relief mode includes the following steps:

[0033] S14. On the basis of the constant pressure mode S1 - S10 or the variable pressure mode S1 - S13, close the outlet start-stop valve at the bottom of the tank body;

[0034] S15. Close the first-stage pressure reducing valve;

[0035] S16. Open the first pressure relief valve and the second pressure relief valve, and open the low-pressure pressure modulator or the high-pressure pressure modulator to the maximum.

[0036] S17. Wait until the low-pressure pressure gauge or the high-pressure pressure gauge returns to zero, close the first start-stop valve and the second start-stop valve, or close the third start-stop valve and the fourth start-stop valve, and adjust the low-pressure pressure modulator or the high-pressure pressure modulator to the flow-stop state.

[0037] In S3, the standard for the sealing between the pool body and the cover plate is that after feeling obvious resistance when rotating the wrench, continue to rotate the screw half a turn.

[0038] In S5, the low-pressure pressure modulator and the high-pressure pressure modulator being in the flow-stop state means relaxing the spring inside the low-pressure pressure modulator and the high-pressure pressure modulator to the maximum, that is, the damping is infinite.

[0039] Furthermore, in S7, the pressure value of the appropriate pressure outlet corresponding to the secondary low-pressure pressure reducing valve is less than the maximum pressure inlet value allowed by the downstream low-pressure pressure modulator.

[0040] Furthermore, in S16, opening the low-pressure pressure modulator or the high-pressure pressure modulator to the maximum means adjusting the pressure knob to make the spring in the most tense state, and at this time, the damping of the low-pressure pressure modulator or the high-pressure pressure modulator is 0.

[0041] Advantages of the present invention: The present invention provides a non-Newtonian fluid high-precision constant inlet pressure control system and its control method based on multi-level regulation. Through the multi-level pressure regulation mechanism, the import pressure fluctuation range is reduced to the 0.01 psi level, greatly improving the accuracy and stability of the non-Newtonian fluid flow pressure control, ensuring reliable and repeatable experimental data. The present invention has wide applicability, can accurately set the pressure for different types of non-Newtonian fluids, is applicable to multiple fields, and adopts a modular design, and the specifications of each component can be flexibly adjusted. The system can freely switch between three modes: constant pressure, variable pressure, and pressure relief, meeting different experimental requirements. The hierarchical pressure regulation and pressure relief protection measures effectively avoid the hidden danger of high-pressure gas leakage. In addition, the system uses standard devices, the range accuracy of the pressure modulator and the liquid pool size can be customized, the maximum adjustable pressure reaches more than 10 atmospheric pressures, and the equipment is miniaturized, with a simple structure and standardized operation, reducing the dependence on professionals and reducing the occupation of human resources. Description of the Drawings

[0042] Figure 1 It is a schematic structural diagram of a non-Newtonian fluid high-precision constant inlet pressure control system based on multi-level regulation of the present invention;

[0043] Figure 2 It is a schematic structural diagram of the multi-level pressure regulating plate;

[0044] Figure 3 It is a schematic structural diagram of a high-pressure liquid storage tank;

[0045] Figure 4 It is Figure 3 a top view of the cover plate in

[0046] Figure 5 It is Figure 3 a top view of the tank body in

[0047] Figure 6 It is Figure 2 a schematic structural diagram of the pressure modulator in

[0048] Among them, 1 is a constant high-pressure gas source, 2 is a multi-stage pressure regulating plate, 3 is a high-pressure liquid storage tank, 4 is a high-pressure gas source, 5 is a first-stage pressure reducing valve, 6 is a first start-stop valve, 7 is a second-stage low-pressure pressure reducing valve, 8 is a low-pressure pressure modulator, 9 is a low-pressure pressure gauge, 10 is a second start-stop valve, 11 is a third start-stop valve, 12 is a high-pressure pressure modulator, 13 is a high-pressure pressure gauge, 14 is a fourth start-stop valve, 15 is a first pressure relief valve, 16 is a second pressure relief valve, 17 is a liquid level gauge, 18 is a cover plate, 19 is a tank body, 20 is an outlet start-stop valve, 21 is a sealing ring, 22 is a screw. Specific embodiments

[0049] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0050] Referring to Figures 1-6 as shown, a non-Newtonian fluid high-precision constant inlet pressure control system based on multi-stage regulation includes: a constant high-pressure gas source 1, a multi-stage pressure regulating plate 2 and a high-pressure liquid storage tank 3. The constant high-pressure gas source 1, the multi-stage pressure regulating plate 2 and the high-pressure liquid storage tank 3 are connected in sequence. Among them, the multi-stage pressure regulating plate 2 includes a high-pressure area and a low-pressure area.

[0051] Specifically, the non-Newtonian fluid high-precision constant inlet pressure control system based on multi-stage regulation described in the present invention innovatively adopts the design concept of multi-stage regulation, by connecting the constant high-pressure gas source 1, the multi-stage pressure regulating plate 2 and the high-pressure liquid storage tank 3 in sequence, especially the multi-stage pressure regulating plate is divided into a high-pressure zone and a low-pressure zone, so as to realize the refined graded regulation of pressure. This design breaks the limitation of the traditional single-stage regulation mode in the prior art and can better adapt to the complex rheological properties of non-Newtonian fluids. The traditional pressure control method is difficult to maintain the stability of the inlet pressure of non-Newtonian fluids, and the multi-stage regulation mechanism of this system can reduce the inlet pressure fluctuation range to 0.01psi level, which greatly guarantees the reliability and repeatability of experimental data. In the experiment and application of high-viscosity and high-elasticity non-Newtonian fluids, its stable pressure output effectively avoids the significant change of flow state caused by small pressure fluctuations, ensuring that the experiment can be carried out accurately. In terms of applicability, the present invention can accurately set the required pressure for different types of non-Newtonian fluids, such as high-viscosity polymer solutions, shear-thinning fluids, etc., and is widely used in fluid mechanics experiments, chemical process control, oil extraction, biomedicine and other fields. In addition, the system adopts a modular design, and the specifications of each component can be flexibly adjusted according to actual needs. Whether it is the pressure reducing valve, pressure modulator, or the size of the liquid storage tank, it can be adapted according to different experimental or industrial scenarios, further enhancing the versatility and practicality of the system. In addition, the system also has outstanding performance in safety. The graded pressure regulation and pressure relief protection measures effectively avoid the safety hazards caused by high-pressure gas leakage. During the experiment or production process, once an abnormal pressure situation occurs, the system can quickly and safely perform pressure relief operations to ensure the personal safety of the operator and the normal operation of the equipment. At the same time, the system has a simple structure and standardized operation. Even personnel who have not received professional training can easily get started, reducing dependence on professionals and reducing human resource costs.

[0052] Furthermore, a constant high-pressure gas source 1 is used to output gas with a constant pressure to a multi-stage pressure regulating plate 2;

[0053] The multi-stage pressure regulating plate 2 is used to output the gas to the high-pressure liquid storage tank 3 through multi-stage pressure regulation;

[0054] The high-pressure liquid storage tank 3 is used to discharge the liquid at a constant pressure in the tank into a preset fluid experiment scene through the gas delivered by the multi-stage pressure regulating plate 2;

[0055] Specifically, the system of the present invention divides the pressure regulation into a low-pressure area and a high-pressure area through a dual-gas-path independent regulation method. In the low-pressure area, the cooperation of the secondary pressure reducing valve and the low-pressure pressure modulator can preliminarily and finely regulate the pressure, providing a stable basis for subsequent high-pressure regulation. This hierarchical regulation method enables the system to more accurately meet the requirements of different pressure ranges. Compared with the traditional single-pressure regulation method, it greatly improves the accuracy and flexibility of pressure regulation. In the high-pressure area, the high-pressure pressure modulator 12 plays an important role. Its unique design can further precisely fine-tune the pressure on the basis of the low-pressure area regulation. The innovative design of the dual-gas-path independent regulation enables the low-pressure area and the high-pressure area to cooperate with each other without interference, effectively avoiding the common pressure fluctuations and regulation errors in traditional pressure regulation systems. In addition, the spring damping regulation and the overflow port design in the pressure modulator further enhance the stability and reliability of the system. The spring damping regulation can be flexibly adjusted according to the actual pressure requirements to ensure the smoothness of pressure changes; while the overflow port plays a safety protection role during the pressure regulation process. When the pressure is too high, it can timely release the excess pressure to prevent the system from being damaged due to overload. The fine design and innovative regulation method of the multi-stage pressure regulating plate 2 of the present invention enable the entire system to have higher accuracy, better stability and stronger adaptability in the pressure control of non-Newtonian fluids.

[0056] Furthermore, the constant high-pressure gas source 1 includes a high-pressure gas source 4 and a primary pressure reducing valve 5. One end of the primary pressure reducing valve 5 is connected to the high-pressure gas source 4, and the other end is connected to the inlet of the multi-stage pressure regulating plate 2.

[0057] Specifically, the structure of the constant high-pressure gas source is clarified in this embodiment. The high-pressure gas source 4 and the primary pressure reducing valve 5 constitute the constant high-pressure gas source, which is the starting link of the system. The high-pressure gas source 4 provides the initial high-pressure gas, and the primary pressure reducing valve 5 is the key component to ensure the stability of the output gas pressure. In traditional pressure control methods, the unstable gas source pressure often leads to difficulties in subsequent pressure regulation and is difficult to meet the high-precision pressure control requirements of non-Newtonian fluids. The presence of the primary pressure reducing valve 5 stabilizes the gas pressure output by the high-pressure gas source 4 at an appropriate value through precise regulation, providing a stable input for the subsequent fine regulation of the multi-stage pressure regulating plate 2. Thus, it lays a solid foundation for the entire pressure regulation chain and ensures that the subsequent links can work stably and precisely. Moreover, this design helps to improve the overall stability and adaptability of the system. In different experimental or engineering scenarios, the required stable gas pressure values may be different. By adjusting the primary pressure reducing valve 5, the output pressure can be easily changed to meet diverse needs. Whether it is an experimental scenario with low pressure requirements or an industrial application with high pressure requirements, the constant high-pressure gas source can provide a stable and reliable gas source, enabling the system to operate stably under various working conditions and greatly enhancing the applicability of the system to the pressure control of different non-Newtonian fluids.

[0058] Further, in the multi-stage pressure regulating plate 2,

[0059] The low-pressure area includes: the first start-stop valve 6, the secondary low-pressure reducing valve 7, the low-pressure pressure modulator 8, the low-pressure pressure gauge 9, and the second start-stop valve 10;

[0060] The high-pressure area includes: the third start-stop valve 11, the high-pressure pressure modulator 12, the high-pressure pressure gauge 13, and the fourth start-stop valve 14;

[0061] The multi-stage pressure regulating plate 2 further includes a first pressure relief valve 15;

[0062] The outlet of the first-stage pressure reducing valve 5 is divided into two paths, which are respectively connected to the first start-stop valve 6 in the low-pressure area and the third start-stop valve 11 in the high-pressure area. The first start-stop valve 6, the secondary low-pressure reducing valve 7, the low-pressure pressure modulator 8, the low-pressure pressure gauge 9, and the second start-stop valve 10 are connected in sequence. The third start-stop valve 11, the high-pressure pressure modulator 12, the high-pressure pressure gauge 13, and the fourth start-stop valve 14 are connected in sequence. The outlets of the second start-stop valve 10 and the fourth start-stop valve 14 are combined and jointly connected to one end of the first pressure relief valve 15 and the upper end of the high-pressure liquid storage tank 3. The other end of the first pressure relief valve 15 is connected to the atmosphere.

[0063] Specifically, in this embodiment, either the high-pressure area or the low-pressure area of the multi-stage pressure regulating plate 2 is selected for use according to the outlet pressure requirement. This design greatly improves the flexibility of the system's pressure regulation. Traditional pressure control methods usually adopt a single regulation mode and are difficult to adapt to the requirements of different pressure ranges. However, in the present invention, by setting the high-pressure area and the low-pressure area, users can select a suitable regulation path according to actual needs. In the case of requiring a lower pressure, the low-pressure area can be selected. The gas pressure is initially reduced by the first pressure reducing valve 5, and then through the fine regulation of the second low-pressure reducing valve 7 and the low-pressure pressure modulator 8, the pressure reaches the expected value. Such a design avoids the problem of excessive pressure that may occur when using the high-pressure area, reduces energy waste, and also reduces equipment loss. On the contrary, in the case of requiring a higher pressure, the high-pressure area can be directly selected for regulation. The high-pressure pressure modulator 12 can precisely fine-tune the gas pressure to meet the experimental or engineering scenarios with high-pressure requirements. This design of flexibly switching the regulation area according to actual needs is like equipping the system with "regulation keys" of different specifications, which can precisely match the "locks" of various pressure requirements, greatly improving the applicability of the system. The setting of the start-stop valve and the pressure relief valve further enhances the safety and controllability of the system. The start-stop valve can control the on-off of the gas. When the system starts, stops, or performs pressure regulation, it can accurately control the gas flow to avoid safety problems caused by gas leakage or pressure fluctuations. The pressure relief valve discharges the excess gas in time when the system pressure is too high to prevent the system from being damaged due to excessive pressure, providing double safety guarantees for the system. Through the innovative design of the multi-stage pressure regulating plate 2 in this embodiment, the system has been significantly improved in terms of pressure regulation flexibility, applicability, safety, and controllability, strongly supporting the control of the high-precision constant inlet pressure of non-Newtonian fluids in the present invention.

[0064] Furthermore, the high-pressure liquid storage tank 3 includes a second pressure relief valve 16, a liquid level gauge 17, a cover plate 18, a tank body 19, and an outlet start-stop valve 20. The cover plate 18 and the upper edge of the tank body 19 are provided with corresponding threaded holes. The cover plate 18, the sealing ring 21, and the tank body 19 are screwed together by screws 22 into the threaded holes from top to bottom to achieve a sealed connection. The cover plate 18 is provided with a second pressure relief valve 16 with one end communicating with the inside of the tank body 19 and the other end communicating with the atmosphere. The liquid level gauge 17 is tubular and is installed outside the tank body 19, and the upper and lower ends are respectively communicated with the upper and lower spaces inside the tank body 19. An outlet start-stop valve 20 is provided at the bottom outlet of the tank body 19.

[0065] Specifically, the high-pressure liquid storage tank 3 is provided with a second pressure relief valve 16, which is a key link to ensure the safe operation of the system. In experiments or engineering applications, non-Newtonian fluids may cause abnormal pressure rise in the system due to various reasons under high pressure, such as temperature changes, fluid flow obstruction, etc. The second pressure relief valve 16 can be opened in time when the pressure exceeds the safety range, and the excess pressure is released to the atmosphere to prevent the tank body 19 from rupturing due to excessive pressure, avoid the danger caused by high-pressure liquid injection, effectively protect the safety of the experimenters and the integrity of the experimental equipment, and solve the problem of insufficient safety of the traditional system under high pressure. The cover plate 18, the sealing ring and the screws are combined with the threaded holes to achieve a closed connection to ensure good sealing of the high-pressure liquid storage tank. The characteristics of non-Newtonian fluids make them more sensitive to environmental factors, and even small leaks may affect their pressure stability and experimental accuracy. This closed design effectively prevents liquid leakage and gas entry, ensures the stability of the pressure in the tank, and provides a solid foundation for the subsequent stable output of constant pressure liquid to the preset fluid experimental scene, thereby improving the stability of the pressure control of the entire system and overcoming the defects of traditional equipment in this regard. The design of the liquid level meter 17 facilitates the operator to observe the amount of liquid in the pool in real time. During the experiment, timely understanding of the remaining liquid can avoid affecting the progress of the experiment due to insufficient liquid, and can also prevent overflow caused by excessive liquid. An outlet start-stop valve 20 is set at the bottom of the pool body 19, which can flexibly control the discharge of liquid, facilitate the timely output of non-Newtonian fluid according to experimental requirements, make the entire operation process smoother and more efficient, and improve the practicality of the system.

[0066] A control method for a non-Newtonian fluid high-precision constant inlet pressure control system based on multi-stage regulation, based on the above-mentioned non-Newtonian fluid high-precision constant inlet pressure control system based on multi-stage regulation, the control method includes a constant pressure mode, a variable pressure mode and a pressure relief mode, wherein:

[0067] The constant voltage mode includes the following steps:

[0068] S1, close the outlet start-stop valve 20 and install the liquid level meter 17;

[0069] S2, placing the prepared non-Newtonian fluid into the pool body 19;

[0070] S3. Place a sealing ring 21 on the upper edge of the cell body 19 and cover the cover plate 18. Tighten the screws 22 to seal the cell body 19 and the cover plate 18. The standard for sealing the cell body 19 and the cover plate 18 is that the screw 22 continues to be rotated half a turn after the wrench feels obvious resistance;

[0071] S4, connecting the first-stage pressure reducing valve 5 to the outlet of the high-pressure gas source 4 and the inlet of the multi-stage pressure regulating plate 2;

[0072] S5. Ensure that the first on-off valve 6, the second on-off valve 10, the third on-off valve 11, and the fourth on-off valve 14 are closed, the low-pressure pressure modulator 8 and the high-pressure pressure modulator 12 are in a flow-stopping state, the first pressure relief valve 15 and the second pressure relief valve 16 are closed, and the low-pressure pressure modulator 8 and the high-pressure pressure modulator 12 are in a flow-stopping state to relax the spring to the maximum, that is, the damping is infinite;

[0073] S6. Open the high-pressure gas source 4 switch to the maximum and the first-stage pressure reducing valve 5 in sequence, and select the low-pressure area or the high-pressure area according to the final outlet pressure;

[0074] S7. If the low-pressure area is selected, open the first on-off valve 6, adjust the second-stage low-pressure pressure reducing valve 7 to an appropriate pressure outlet, or open the third on-off valve 11. The appropriate pressure outlet corresponding to the second-stage low-pressure pressure reducing valve 7 is less than the maximum allowable pressure inlet of the downstream low-pressure pressure modulator 8;

[0075] S8. Adjust the low-pressure pressure modulator 8 or the high-pressure pressure modulator 12 to obtain the expected pressure value on the low-pressure pressure gauge 9 or the high-pressure pressure gauge 13;

[0076] S9. Open the second on-off valve 10 or the fourth on-off valve 14 and wait for the low-pressure pressure modulator 8 or the high-pressure pressure modulator 12 to stably drop back to the expected pressure value;

[0077] S10. Open the outlet on-off valve 20 to stably discharge the non-Newtonian fluid. The on-off valve of the present invention can be replaced with an electromagnetic valve. The electromagnetic valve has a fast response time and can perform potential control;

[0078] The constant pressure mode includes the following steps:

[0079] S11. On the basis of S1-S10, close the second on-off valve 10 or the fourth on-off valve 14;

[0080] S12. Fine-tune the low-pressure pressure modulator 8 or the high-pressure pressure modulator 12 to make the low-pressure pressure gauge 9 or the high-pressure pressure gauge 13 change to a new expected pressure value. Fine-tuning the low-pressure pressure modulator 8 or the high-pressure pressure modulator 12 means that the rotation amount of the knob is small. With the double guarantee of high precision of the pressure modulator and small pressure change amount, a small-increment pressure change is achieved. Moreover, the pressure modulator has an overflow port. After the pressure is adjusted down, the high pressure at the lower end can be released to achieve balance;

[0081] S13. Open the second on-off valve 10 or the fourth on-off valve 14. After opening the second on-off valve 10 or the fourth on-off valve 14, the downstream pressure will quickly respond to the adjustment of the low-pressure pressure modulator 8 or the high-pressure pressure modulator 12, and the pressure in the cell 19 will change to the expected pressure within the millimeter level, realizing micro-precision variable pressure regulation;

[0082] The pressure relief mode includes the following steps:

[0083] S14. On the basis of the constant pressure mode S1 - S10 or the variable pressure mode S1 - S13, close the outlet start-stop valve 20 at the bottom of the cell body 19;

[0084] S15. Close the first pressure reducing valve 5;

[0085] S16. Open the first pressure relief valve 15 and the second pressure relief valve 16, open the low-pressure pressure modulator 8 or the high-pressure pressure modulator 12 to the maximum. The maximum of the low-pressure pressure modulator 8 or the high-pressure pressure modulator 12 is to adjust the pressure knob to the tightest state of the spring, so that the damping of the modulator is 0;

[0086] S17. Wait until the low-pressure pressure gauge 9 or the high-pressure pressure gauge 13 returns to zero, close the first start-stop valve 6 and the second start-stop valve 10, or close the third start-stop valve 11 and the fourth start-stop valve 14, and adjust the low-pressure pressure modulator 8 or the high-pressure pressure modulator 12 to the stop-flow state.

[0087] Specifically, this embodiment elaborates on the control method of the non-Newtonian fluid high-precision constant inlet pressure control system based on multi-stage regulation, covering three modes: constant pressure, variable pressure and pressure relief. In the constant pressure mode, the system is prepared, assembled, connected and debugged in an orderly manner, and finally achieves a stable pressure output. From closing the outlet start-stop valve 20, installing the liquid level meter 17, placing the non-Newtonian fluid into the pool body 19 and sealing it, to accurately adjusting the valves and pressure modulators at all levels, this series of steps ensures that a stable inlet pressure environment can be provided for non-Newtonian fluids in experiments or engineering applications. In the case where the traditional pressure control method is difficult to maintain a stable pressure, the constant pressure mode of the present invention uses the high pressure area and low pressure area in the multi-stage pressure regulating plate 2 through graded regulation to accurately set the pressure according to different needs. For example, according to the final outlet pressure, the appropriate area is selected for adjustment, and the pressure modulators and pressure gauges at all levels are matched to control the inlet pressure fluctuation range to a very small level, which greatly improves the pressure control accuracy, ensures the reliability of the experimental data and the repeatability of the experimental results, and is a major breakthrough in traditional technology. The variable pressure mode further demonstrates the flexibility and accuracy of the system. On the basis of constant pressure mode, precise pressure adjustment can be achieved by simply closing the corresponding start-stop valve, fine-tuning the pressure modulator and opening the start-stop valve again. This process makes full use of the high-precision characteristics of the pressure modulator in the system. A small turn of the knob can bring about precise pressure changes, and the overflow port design of the pressure modulator ensures the stability and safety of pressure adjustment. This ability to achieve precise changes within a very small pressure range meets the demand for dynamic pressure adjustment during experiments or production processes. It can flexibly change pressure conditions according to actual conditions and adapt to the research or application requirements of non-Newtonian fluids at different stages, so that the system is no longer limited to a single pressure condition, greatly expanding the application scenarios. The pressure relief mode is an important guarantee for system safety. When the experiment is over or the system is abnormal, follow the steps of the pressure relief mode, close the relevant valves and open the pressure relief valve to safely release the pressure in the system. This mode effectively avoids safety hazards that may be caused by residual high-pressure gas or liquid in the system, such as high-pressure gas leakage and equipment damage. By adjusting the pressure modulator to the maximum, the pressure is quickly returned to zero. The operation is simple and efficient, ensuring the safe operation of the system under various conditions and providing a reliable protection mechanism for operators and equipment. Through the organic combination of the three modes, not only high-precision and stable control of the inlet pressure of non-Newtonian fluids is achieved, but also the flexibility and safety of the system are taken into account.

[0088] Furthermore, in S3, the standard for the sealing between the cell body 19 and the cover plate 18 is that after the wrench feels obvious resistance, the screw 22 continues to be rotated half a circle.

[0089] Specifically, the sealing standard of this embodiment ensures good sealing of the high-pressure liquid storage tank. Non-Newtonian fluid experiments or applications are often carried out under high-pressure environments. If the seal is not tight, it will not only cause liquid leakage, affecting the accuracy of the experimental results and the safety of engineering applications, but also may allow external impurities to enter, interfere with the fluid properties, and destroy the stability of pressure control. By clarifying the sealing standard, the present invention can ensure that each operation can achieve a stable and reliable sealing effect, avoid various problems caused by improper sealing, and provide a solid hardware foundation for the system to achieve high-precision constant inlet pressure control. At the same time, standardized operations also reduce the impact of subjective differences among operators and improve the consistency and repeatability of system operation.

[0090] Furthermore, in S5, the low-pressure modulator 8 and the high-pressure modulator 12 are in a flow-stopping state to relax the springs inside the low-pressure modulator 8 and the high-pressure modulator 12 to the maximum, that is, the damping is infinite.

[0091] Specifically, in the preparation stage before the system starts, putting the pressure modulator in this state can effectively prevent the gas from flowing freely when the system debugging and preparation work are not completed, and prevent unexpected pressure fluctuations. Moreover, when closing the relevant start and stop valves and preparing to open the gas source for pressure regulation, the stop flow state can avoid instantaneous pressure changes caused by the pressure modulator not being in a suitable state, reducing the impact on system components and extending the service life of the equipment. At the same time, the stable starting state enables operators to operate more calmly and accurately according to the subsequent steps, reducing operational errors caused by unstable pressure, and ensuring the smooth progress of the entire pressure regulation process, thereby better realizing the control of high-precision constant inlet pressure of non-Newtonian fluids.

[0092] Further, in S7 , the pressure value of the appropriate pressure outlet corresponding to the secondary low-pressure reducing valve 7 is less than the maximum pressure inlet value allowed by the downstream low-pressure pressure modulator 8 .

[0093] Specifically, in the multi-stage control system of the present invention, this limitation of the present embodiment ensures the orderliness and stability of the system pressure regulation. The secondary low-pressure pressure reducing valve 7 is an important link in the pressure regulation of the low-pressure zone, and the reasonable setting of its outlet pressure is the basis for subsequent precise control. If the outlet pressure of the secondary low-pressure pressure reducing valve 7 is too high and exceeds the tolerance range of the downstream low-pressure pressure modulator, not only will the low-pressure pressure modulator 8 be unable to work normally, but it may also cause the pressure of the entire low-pressure zone to be out of control, thereby affecting the system's precise control of the inlet pressure of the non-Newtonian fluid. By clarifying the magnitude relationship of this pressure value, a stable logical sequence is established for the pressure regulation process of the system, so that the gas can smoothly pass through each regulating component in the low-pressure zone, and gradually realize the fine adjustment of the pressure. From the perspective of precision control, this setting helps to improve the accuracy of pressure regulation. In the experiment and application of non-Newtonian fluids, the precision requirements for pressure are extremely high. The reasonable cooperation between the secondary low-pressure pressure reducing valve 7 and the downstream low-pressure pressure modulator 8 can avoid the regulation error caused by excessive pressure or excessive fluctuation. When the output pressure of the secondary low-pressure pressure reducing valve 7 is within the appropriate range, the low-pressure pressure modulator 8 can fine-tune the pressure more accurately, and combined with the feedback of the pressure gauge, the final output pressure can be closer to the expected value, thereby meeting the needs of non-Newtonian fluids for high-precision pressure control. This optimization of the pressure regulation accuracy is an important embodiment of the multi-stage control technology of the present invention in achieving high-precision pressure control. In addition, this limitation also enhances the reliability and safety of the system. Reasonable pressure matching can effectively avoid damage to the equipment caused by pressure overload. The low-pressure pressure modulator 8 has a certain pressure tolerance range when designed. When the outlet pressure of the secondary low-pressure pressure reducing valve 7 does not exceed its maximum allowable inlet pressure, the risk of damage to the modulator due to overpressure can be reduced, and the service life of the equipment can be extended. At the same time, the stable pressure regulation process also reduces safety hazards such as gas leakage caused by abnormal pressure, and ensures the safety of the experimental and production environment. This is highly consistent with the innovative concept of the present invention in ensuring the safe and stable operation of the system, and further improves the performance of the entire system.

[0094] Further, in S16, the low-pressure modulator 8 or the high-pressure modulator 12 is opened to the maximum, that is, the pressure knob is adjusted to make the spring in the most tense state. At this time, the damping of the low-pressure modulator 8 or the high-pressure modulator 12 is 0.

[0095] Specifically, this embodiment clarifies the specific operation method and corresponding state of opening the low-pressure or high-pressure pressure modulator to the maximum. In the pressure relief mode, the pressure knob of the pressure modulator is adjusted to the state where the spring is most tightened and the damping is 0, which can quickly and thoroughly release the pressure in the system. This precise operation setting ensures the efficiency and safety of the pressure relief process, avoiding potential safety hazards caused by untimely or incomplete pressure relief. After the experiment or production is completed, rapid and complete pressure relief is crucial for ensuring the safety of operators and facilitating subsequent equipment maintenance. It enables more precise and stable pressure regulation when the system switches between different working modes.

[0096] Based on the special rheological properties of non-Newtonian fluids, the present invention proposes a multi-level regulated high-precision inlet pressure control system, which exhibits the following common laws during the pressure regulation process:

[0097] (1) Multi-level pressure regulation is the core mechanism for the stable control of non-Newtonian fluids

[0098] Due to the viscoelasticity and shear-dependent characteristics of non-Newtonian fluids, the flow behavior of the fluid is extremely sensitive to pressure fluctuations. Single-level pressure regulation often has difficulty in stabilizing the inlet pressure, easily causing flow instability, and even leading to experimental errors or system failures. By adopting a multi-level regulation mode, with preliminary regulation provided by the high-pressure area and micro-regulation in the low-pressure area, pressure fluctuations can be effectively reduced and pressure stability can be improved.

[0099] (2) Fine pressure regulation depends on pressure level design and feedback regulation

[0100] During the control process of non-Newtonian fluids, the coordination between different pressure levels is crucial. The high-pressure regulation area ensures that the system has sufficient pressure regulation range, while the low-pressure regulation area provides fine adjustment capabilities. The accuracy of pressure not only depends on the number of regulation levels but is also closely related to the feedback regulation mechanism. This system combines step-by-step regulation with feedback regulation to achieve a pressure regulation accuracy of 0.01 psi, making the pressure control more in line with the rheological requirements of non-Newtonian fluids.

[0101] (3) Combining pressure relief with steady-state regulation to ensure flow stability and system safety

[0102] During the flow process of non-Newtonian fluids, the characteristics of the viscoelasticity and shear viscosity dependence relationship may cause pressure mutations, thereby affecting the flow state. Traditional pressure control systems often have difficulty in effectively coping with sudden pressure changes, resulting in flow instability and even equipment damage. This system combines the pressure relief mode with steady-state pressure control, adopts step-by-step pressure relief and dynamic regulation to ensure the smooth release of fluid pressure, prevent violent fluctuations, and improve the overall safety and flow stability of the system.

[0103] (4) Modular and standardized design enhances system adaptability

[0104] Since different types of non-Newtonian fluids have significant differences in rheological properties, a single pressure control system is difficult to adapt to a wide range of application needs. The present invention adopts a modular structure, and all core components can be replaced and adjusted, including pressure modulators, pressure reducing valves, liquid storage tanks, etc., which can be flexibly adjusted according to fluid types and experimental requirements, so that the system can adapt to different non-Newtonian fluid flow control scenarios and improve scalability and versatility.

[0105] The present invention has successfully developed a high-precision constant inlet pressure control system for non-Newtonian fluids based on multi-level regulation, breaking through the technical bottleneck of traditional pressure control methods in the application of non-Newtonian fluids. Research shows that:

[0106] (1) The multi-level control mode can effectively improve the pressure stability of non-Newtonian fluids

[0107] Since non-Newtonian fluids are highly sensitive to the external environment, traditional single-stage pressure control is difficult to meet the flow stability requirements. The present invention adopts a graded control mode to significantly reduce the pressure fluctuation amplitude, maintain the pressure at the 0.01psi level, ensure the stability of fluid flow, and provide an effective solution for the precise control of non-Newtonian fluids.

[0108] (2) Joint regulation of high and low pressure areas to achieve a combination of large-scale regulation and high-precision fine-tuning

[0109] The high-pressure area provides a large pressure regulation capability, while the low-pressure area is responsible for fine adjustment, so that the system can achieve precise regulation in a wide range. By comparing with traditional regulation methods, this system not only ensures pressure stability, but also enhances applicability, so that it can meet the flow control needs of non-Newtonian fluids under different working conditions.

[0110] (3) Multi-mode pressure regulation mechanism improves the repeatability and accuracy of non-Newtonian fluid experiments

[0111] By switching between constant pressure, variable pressure and pressure relief modes, the system can flexibly adjust the inlet pressure according to the needs of experiments or engineering applications, improving the repeatability and stability of non-Newtonian fluid flow control, so that it still has high accuracy and reliability in complex flow environments.

[0112] (4) Pressure relief protection mechanism enhances system safety and prevents high-pressure shock and fluid instability

[0113] The step-by-step pressure relief and automatic pressure adjustment mode are adopted to ensure that the pressure release process is smooth and controllable, and to prevent sudden pressure changes from having adverse effects on fluid flow and equipment safety. The pressure relief protection mechanism significantly reduces the risk of damage to experimental equipment and improves the stability and safety of the system's long-term operation.

[0114] (5) Modular design improves the flexibility of engineering applications

[0115] By using standardized components, each part can flexibly adjust parameters according to experimental or engineering requirements, making the system applicable to different types of non-Newtonian fluid control scenarios, improving the applicability and engineering feasibility of the equipment. At the same time, the system has a compact structure and is easy to operate, which reduces dependence on professionals and improves the efficiency and accuracy of non-Newtonian fluid experiments.

[0116] In summary, the present invention provides an efficient, safe and stable solution for high-precision pressure control of non-Newtonian fluids, and has important application value in the fields of fluid mechanics experiments, oil extraction, chemical process control, etc.

[0117] The present invention is the first to create an independent dual-gas-circuit control architecture for high-pressure and low-pressure areas, and realizes pressure gradient control through a three-stage pressure regulation mechanism, namely, a primary pressure reducing valve → a secondary pressure reducing valve → a pressure modulator. In the low-pressure area, a secondary low-pressure pressure reducing valve 7 and a low-pressure pressure modulator 8 are connected in series to reduce the initial high-pressure gas source to a range of 0.1-10psi; the high-pressure area is directly controlled by a high-pressure pressure modulator 12 to achieve precise control of 1-100psi. This hierarchical control mode of the present invention breaks through the ±10% pressure fluctuation limit of the traditional single-stage pressure reducing valve, and controls the inlet pressure fluctuation within ±0.01psi, which is particularly suitable for the pressure stability requirements of complex non-Newtonian fluids such as shear thinning and viscoelasticity.

[0118] The present invention achieves continuous pressure regulation of 0-100psi by rotating the knob to change the spring preload. Its unique overflow port structure automatically releases excess gas when the pressure is reduced, and with the real-time feedback of the pressure gauge, it can achieve fine-tuning of pressure at the level of 0.01psi. In the variable pressure mode, by closing the start-stop valve to form a closed air chamber, the dynamic response characteristics of the pressure modulator are utilized to complete the pressure step change and stabilize it within 3 seconds, and the response speed is greatly improved compared with the traditional system.

[0119] In the field of non-Newtonian fluid pressure control, traditional technologies have always faced three core problems: first, the single-stage control mode is difficult to cope with the complex rheological properties of non-Newtonian fluids, resulting in insufficient repeatability of experimental data; second, the lack of high-precision micro-adjustment capabilities under high-pressure conditions cannot meet the needs of precision control; third, the lack of an effective safety protection mechanism poses a risk of high-pressure leakage. In response to these technical bottlenecks, the present invention constructs a non-Newtonian fluid high-precision constant inlet pressure control system based on multi-stage control.

[0120] The core technical solution of the present invention consists of a three - level regulation architecture. First, the initial gas source is stepped down to a controllable range by a constant high - pressure gas source (1), and the first - stage pressure reducing valve 5 can provide a stable gas source input. The key breakthrough lies in the dual - gas - path independent regulation of the multi - stage pressure regulating plate 2: in the low - pressure area, through the series combination of the second - stage low - pressure reducing valve 7 and the low - pressure pressure modulator 8, precise regulation of 0.1 - 10 psi is achieved; in the high - pressure area, the high - pressure pressure modulator 12 is directly used for rough adjustment of 1 - 100 psi. This hierarchical regulation mode breaks through the ±0.5 psi pressure fluctuation limit of traditional single - stage regulation, controls the inlet pressure fluctuation within ±0.01 psi, and ensures the reliability and repeatability of non - Newtonian fluid experimental data.

[0121] In terms of pressure modulation technology, the present invention innovatively designs a dynamic pressure modulator with an overflow port. By rotating the knob to change the spring pre - tightening force, continuous pressure regulation at the 0.01 psi level is achieved. With the real - time feedback of the pressure gauge, the pressure step change can be completed and stabilized within 3 seconds. In view of the shear - thinning property of non - Newtonian fluids, the high - pressure liquid storage tank 3 adopts a large - diameter outlet combined with a low - damping modulator, effectively reducing the influence of flow resistance on pressure stability.

[0122] In terms of safety protection and engineering adaptability, the present invention constructs a solid and reliable safety system with ingenious hardware design. At the hardware level, by setting the upper limit of the outlet pressure of the second - stage pressure reducing valve, the pressure entering the downstream is strictly restricted, reducing the over - pressure risk from the source. At the same time, the system is equipped with dual pressure relief valves, namely the first pressure relief valve 15 and the second pressure relief valve 16. Working together, when the pressure rises abnormally, they can timely and effectively release the excess pressure, providing double insurance for the system and jointly forming a solid three - level protection mechanism, effectively ensuring the safe operation of the system in a high - pressure environment. In terms of engineering adaptability, the present invention adopts a modular design concept, and the specifications of each component are ingeniously designed, enabling the pressure modulator and the high - pressure liquid storage tank 3 to be quickly replaced. This design greatly improves the versatility of the system, and it can be easily adapted whether it is used for microfluidic experiments to meet fine experimental requirements or applied to industrial - scale production to handle large - scale fluid processing.

[0123] Through a multi-level pressure regulation mechanism, the present invention reduces the import pressure fluctuation range to the level of 0.01 psi, greatly improving the accuracy and stability of the flow pressure control of non-Newtonian fluids, and ensuring reliable and repeatable experimental data. The present invention has wide applicability, can accurately set the pressure for different types of non-Newtonian fluids, is applicable to multiple fields, and adopts a modular design, with the specifications of each component being flexibly adjustable. The system can freely switch among three modes: constant pressure, variable pressure, and pressure relief, meeting different experimental requirements. The hierarchical pressure regulation and pressure relief protection measures effectively avoid potential hazards of high-pressure gas leakage. In addition, the system uses standard devices, the range accuracy of the pressure modulator and the size of the liquid pool can be customized, the maximum adjustable pressure reaches more than 10 atmospheres, and the equipment is miniaturized, with a simple structure and standardized operation, reducing the dependence on professionals and the occupation of human resources.

[0124] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed by this application can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.

Claims

1. A high-precision constant inlet pressure control system for non-Newtonian fluids based on multi-level regulation, characterized in that, Comprising: A constant high-pressure gas source (1), a multi-stage pressure regulating plate (2), and a high-pressure liquid storage tank (3). The constant high-pressure gas source (1), the multi-stage pressure regulating plate (2), and the high-pressure liquid storage tank (3) are connected in sequence. Among them, the multi-stage pressure regulating plate (2) includes a high-pressure area and a low-pressure area.

2. The non-Newtonian fluid high-precision constant inlet pressure control system based on multi-stage regulation according to claim 1, characterized in that The constant high-pressure gas source (1) is used to output gas with a constant pressure to the multi-stage pressure regulating plate (2); The multi-stage pressure regulating plate (2) is used to output gas to the high-pressure liquid storage tank (3) through multi-stage pressure regulation; The high-pressure liquid storage tank (3) is used to discharge the liquid with a constant pressure in the tank into a preset fluid experiment scenario through the gas transported by the multi-stage pressure regulating plate (2).

3. The high-precision constant inlet pressure control system for non-Newtonian fluids based on multi-level regulation according to claim 2, wherein The constant high-pressure gas source (1) includes a high-pressure gas source (4) and a first pressure reducing valve (5). One end of the first pressure reducing valve (5) is connected to the high-pressure gas source (4), and the other end is connected to the inlet of the multi-stage pressure regulating plate (2).

4. The non-Newtonian fluid high-precision constant inlet pressure control system based on multi-level regulation according to claim 3, wherein In the multi-stage pressure regulating plate (2), The low-pressure area includes: a first start-stop valve (6), a second low-pressure pressure reducing valve (7), a low-pressure pressure modulator (8), a low-pressure pressure gauge (9), and a second start-stop valve (10); The high-pressure area includes: a third start-stop valve (11), a high-pressure pressure modulator (12), a high-pressure pressure gauge (13), and a fourth start-stop valve (14); The multi-stage pressure regulating plate (2) further includes a first pressure relief valve (15); The outlet of the first pressure reducing valve (5) is divided into two paths, which are respectively connected to the first start-stop valve (6) in the low-pressure area and the third start-stop valve (11) in the high-pressure area. The first start-stop valve (6), the second low-pressure pressure reducing valve (7), the low-pressure pressure modulator (8), the low-pressure pressure gauge (9), and the second start-stop valve (10) are connected in sequence. The third start-stop valve (11), the high-pressure pressure modulator (12), the high-pressure pressure gauge (13), and the fourth start-stop valve (14) are connected in sequence. The outlets of the second start-stop valve (10) and the fourth start-stop valve (14) are combined and commonly connected to one end of the first pressure relief valve (15) and the upper end of the high-pressure liquid storage tank (3). The other end of the first pressure relief valve (15) is connected to the atmosphere.

5. The non-Newtonian fluid high-precision constant inlet pressure control system based on multi-level regulation according to claim 4, wherein The high-pressure liquid storage tank (3) includes a second pressure relief valve (16), a liquid level gauge (17), a cover plate (18), a tank body (19), and an outlet start-stop valve (20). Corresponding threaded holes are provided on the upper edge of the cover plate (18) and the tank body (19). The cover plate (18), the sealing ring (21), and the tank body (19) are screwed together by screws (22) into the threaded holes from top to bottom to achieve a sealed connection. A second pressure relief valve (16) with one end connected to the inside of the tank body (19) and the other end connected to the atmosphere is provided on the cover plate (18). The liquid level gauge (17) is tubular and is installed outside the tank body (19), and the upper and lower ends are respectively connected to the upper and lower spaces inside the tank body (19). An outlet start-stop valve (20) is provided at the bottom outlet of the tank body (19).

6. A control method for a high-precision constant inlet pressure control system of non-Newtonian fluid based on multi-level regulation, based on the high-precision constant inlet pressure control system of non-Newtonian fluid based on multi-level regulation according to any one of claims 1-5, characterized in that, The control method includes a constant pressure mode, a variable pressure mode, and a pressure relief mode. Among them, The constant pressure mode includes the following steps: S1. Close the outlet start-stop valve (20) and install the liquid level indicator (17); S2, placing the prepared non-Newtonian fluid into the pool body (19); S3. Place a sealing ring (21) on the upper edge of the tank body (19), cover the tank body (19) with the cover plate (18), and assemble and seal the tank body (19) and the cover plate (18) by tightening the screws (22); S4, connecting the first-stage pressure reducing valve (5) to the outlet of the high-pressure gas source (4) and the inlet of the multi-stage pressure regulating plate (2); S5, ensuring that the first start-stop valve (6), the second start-stop valve (10), the third start-stop valve (11), and the fourth start-stop valve (14) are closed, the low-pressure modulator (8) and the high-pressure modulator (12) are in a flow-stopping state, and the first pressure relief valve (15) and the second pressure relief valve (16) are closed; S6, turn on the high-pressure gas source (4) switch to the maximum and first-stage pressure reducing valves (5) in sequence, and select the low-pressure zone or high-pressure zone according to the final outlet pressure; S7. If the low-pressure zone is selected, open the first start-stop valve (6), adjust the secondary low-pressure relief valve (7) to a suitable pressure outlet, or open the third start-stop valve (11); S8, adjusting the low-pressure modulator (8) or the high-pressure modulator (12), the low-pressure gauge (9) or the high-pressure gauge (13) to obtain the expected pressure value; S9, opening the second start-stop valve (10) or the fourth start-stop valve (14), and waiting for the low-pressure modulator (8) or the high-pressure modulator (12) to stabilize and fall back to the expected pressure value; S10, opening the outlet start-stop valve (20) to discharge the non-Newtonian fluid stably; The constant voltage mode includes the following steps: S11, based on S1-S10, close the second start-stop valve (10) or the fourth start-stop valve (14); S12, fine-tuning the low-pressure modulator (8) or the high-pressure modulator (12) to change the low-pressure gauge (9) or the high-pressure gauge (13) to a new expected pressure value; S13, opening the second start-stop valve (10) or the fourth start-stop valve (14); The pressure relief mode includes the following steps: S14, based on the constant pressure mode S1-S10 or the variable pressure mode S1-S13, close the outlet start-stop valve (20) at the bottom of the tank body (19); S15, closing the first pressure reducing valve (5); S16, opening the first pressure relief valve (15) and the second pressure relief valve (16), and opening the low-pressure pressure modulator (8) or the high-pressure pressure modulator (12) to the maximum; S17, wait until the low-pressure gauge (9) or the high-pressure gauge (13) returns to zero, close the first start-stop valve (6) and the second start-stop valve (10), or close the third start-stop valve (11) and the fourth start-stop valve (14), and adjust the low-pressure modulator (8) or the high-pressure modulator (12) to a stop flow state.

7. The control method of the non-Newtonian fluid high-precision constant inlet pressure control system based on multi-level regulation according to claim 6, characterized in that In S3, the standard for the sealing between the cell body (19) and the cover plate (18) is that after the wrench feels obvious resistance, the screw (22) continues to be rotated half a turn.

8. The control method of the non-Newtonian fluid high-precision constant inlet pressure control system based on multi-level regulation according to claim 7, characterized in that, In S5, the low-pressure modulator (8) and the high-pressure modulator (12) are in a flow-stopping state, which means that the springs inside the low-pressure modulator (8) and the high-pressure modulator (12) are relaxed to the maximum, that is, the damping is infinite.

9. The control method of the non-Newtonian fluid high-precision constant inlet pressure control system based on multi-level regulation according to claim 8, characterized in that, In S7, the pressure value of the appropriate pressure outlet corresponding to the secondary low-pressure pressure reducing valve (7) is less than the maximum pressure inlet value allowed by the downstream low-pressure pressure modulator (8).

10. The control method of the non-Newtonian fluid high-precision constant inlet pressure control system based on multi-level regulation according to claim 9, characterized in that, In S16, open the low-pressure pressure modulator (8) or the high-pressure pressure modulator (12) to the maximum to adjust the pressure knob to make the spring in the most tense state. At this time, the damping of the low-pressure pressure modulator (8) or the high-pressure pressure modulator (12) is 0.

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