Multi-process anti-gravity double-parallel digital coupling gas supply vacuum collaborative control method

Abstract

The application provides a multi-process anti-gravity double-parallel digital coupling gas supply vacuum collaborative control method, which is executed by integrated casting equipment, wherein the integrated equipment comprises a casting tank assembly, a double-parallel large-flow digital valve ultra-fast pressure boosting pneumatic control assembly, a staged vacuum obtaining assembly, a variable frequency air pressure supply assembly, a multi-component mixed gas protection assembly and an electric control assembly; the method comprises the following steps: a double-medium pre-energy storage standby control step; a tank sealing interlocking isolation step; a seven-casting-process mode coupling collaborative control step; a pressure maintaining dynamic compensation control step; and a staged pressure relief opening tank interlocking step. The application can integrate the double-parallel digital valve gas supply, pre-vacuum energy storage and integrated collaborative control of seven casting processes, i.e. low pressure, differential pressure, pressure regulation, pressure regulation filling type pressurization solidification, vacuum suction casting, suspension and inert protective atmosphere differential pressure.

Description

Technical Field

[0001] This invention belongs to the field of intelligent control technology for anti-gravity casting of aluminum alloys. Specifically, it relates to a dual-parallel digital valve gas supply and pre-vacuum energy storage integrated collaborative control method that integrates seven casting processes: low pressure, differential pressure, pressure regulation, pressure regulation filling and solidification, vacuum suction casting, suspension, and inert protective atmosphere differential pressure. Background Technology

[0002] Currently, the gas supply system and vacuum system of existing anti-gravity casting equipment are controlled independently, which presents many pain points in the industry:

[0003] The gas supply pipelines share a single main pipe, and the upper and lower tanks can only be filled with gas at different times, making it impossible to control the pressure synchronously and independently; the pipelines have a large number of bends and diameter changes, resulting in high airflow resistance, slow pressurization rate, uneven gas pressure distribution in the tanks, and poor consistency of filling quality.

[0004] The gas supply valve assembly adopts a single-set design with no hardware redundancy. Valve failure will cause the entire machine to shut down, resulting in poor production continuity. Conventional valves have slow response speed and low pressure control accuracy, making it impossible to meet the requirements of the ultra-fast pressurization solidification process.

[0005] The vacuum system has no pre-evacuation energy storage tank. Each casting requires a separate vacuuming of the large-volume casting tank, which takes a long time and results in a long production cycle. When switching between the vacuum and gas supply systems, the air must be broken and the pressure released, which can easily cause air to be drawn into the mold cavity, leading to a high incidence of porosity and looseness defects in the castings.

[0006] The control mode is singular, only supporting pure pressure filling, and complex cavity filling is prone to molten metal blowout; there is no layered liquid surface contact linkage pressure relief logic, so it cannot automatically relieve pressure in the event of a fire, which poses a safety hazard;

[0007] The seven casting processes require manual disassembly and assembly of pipelines and switching of valves, resulting in low automation and time-consuming process switching, making it impossible to achieve fully closed-loop automated production.

[0008] Existing conventional control methods cannot achieve continuous coupling and regulation of three media without cavitation, namely vacuum negative pressure, high-pressure compressed air, and inert protective gas. This cannot meet the core requirements of the new pressure-regulated filling and pressurized solidification process of "negative pressure filling and instantaneous high-pressure forced feeding", and the density of the castings is difficult to meet the standards.

[0009] Therefore, developing a dual-parallel digital valve gas supply and pre-vacuum energy storage integrated collaborative control method that integrates seven casting processes—low pressure, differential pressure, pressure regulation, pressure filling and solidification, vacuum casting, suspension, and inert protective atmosphere differential pressure—is a technical problem that the industry urgently needs to solve. Summary of the Invention

[0010] A primary objective of this invention is to overcome at least one of the deficiencies of the prior art and provide a multi-process anti-gravity dual-parallel digital coupling gas supply vacuum collaborative control method that integrates seven casting processes: low pressure, differential pressure, pressure regulation, pressure regulating filling and solidification, vacuum casting, suspension, and inert protective atmosphere differential pressure. This method features integrated collaborative control of dual parallel digital valve gas supply and pre-vacuum energy storage.

[0011] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0012] According to one aspect of the present invention, a multi-process anti-gravity dual parallel digital coupling gas supply vacuum collaborative control method is provided. The method is executed based on an integrated casting equipment, the integrated equipment comprising a casting tank assembly, a dual parallel high-flow digital valve rapid pressurization gas control assembly, a staged vacuum acquisition assembly, a variable frequency air supply assembly, a multi-component gas mixing protection assembly, and an electrical control assembly.

[0013] The casting tank assembly is equipped with an independent upper tank air inlet branch and an independent lower tank air inlet main branch;

[0014] The dual parallel high-flow digital valve high-speed booster pneumatic control assembly includes two sets of mutually redundant FESTO high-speed digital valve groups, with a single valve action response time of 35ms, and is equipped with bottom, middle, top, and fire-running layered contact signal acquisition modules.

[0015] The graded vacuum assembly includes a 10m³ pre-vacuum storage tank and a dual rotary vane pump + Roots pump vacuum unit.

[0016] The variable frequency air compressor supply assembly includes a 75KW variable frequency air compressor and three 10m³ parallel high-pressure air storage tanks;

[0017] The electronic control assembly incorporates a PLC fuzzy PID controller and a 0.1-level differential pressure sensor.

[0018] The cooperative control method includes the following steps:

[0019] S1. Dual-medium pre-energy storage standby control steps: During the equipment standby phase, the 75KW variable frequency air compressor continuously supplies air to the three 10m³ parallel high-pressure air storage tanks, and the air storage tank pressure is stabilized at 0.95MPa-1MPa; the staged vacuum unit continuously evacuates the 10m³ pre-evacuation vacuum energy storage tank, and the absolute pressure of the pre-evacuation tank is ≤50Pa; all dual parallel digital valve groups are closed, the upper and lower tank connection valves are opened, and the tank is in standby at normal pressure;

[0020] S2, Tank sealing interlock isolation steps: The hydraulic locking cylinder pulls the flange, and the magnetic ring switch transmits the locking signal to the PLC; After receiving the signal, the PLC closes the upper and lower tank connection valve, physically isolating the independent upper tank air inlet branch and the independent lower tank air inlet main branch. The two air routes are controlled by two sets of independent parallel digital valve groups respectively.

[0021] S3, Seven casting processes are coupled and coordinated in different modes, including seven independent control processes: low pressure, differential pressure, pressure regulation, pressure regulation filling and pressurization solidification, vacuum casting, suspension, and inert protective atmosphere differential pressure.

[0022] S4. Pressure holding dynamic compensation control steps: During the pressure holding stage, the pressure sensors of the upper and lower tanks collect the circuit pressure in real time, and the PLC independently identifies the leakage of the upper and lower tanks and controls the corresponding digital valves to automatically compensate for the pressure in a small amount.

[0023] S5. Staged pressure relief and tank opening interlock steps: After crystallization is completed, the PLC layered contact signal executes multi-stage pressure relief. After the tank pressure stabilizes in the range of -2KPa to +2KPa, the tank opening interlock is unlocked.

[0024] According to one embodiment of the present invention, S3 includes:

[0025] S3-1 Low-Pressure Casting Collaborative Control Process: The PLC only opens the digital valve group corresponding to the independent lower air intake main pipe, while all valve groups of the upper tank's annular air intake branch are shut off; the system can switch between pressure filling and flow filling dual control modes. In pressure filling mode, the pressure control accuracy is ≤0.5KPa throughout the process, while in flow filling mode, the air supply flow is constant to avoid aluminum liquid blowout caused by changes in the cavity cross-section; after the filling, shelling, and crystallization processes are completed, only the lower tank is subjected to staged pressure relief, and the tank opening interlock is unlocked after the pressure inside the tank returns to zero;

[0026] S3-2 Differential Pressure Casting Collaborative Control Process: The PLC synchronously opens the digital valve groups of the upper and lower tanks, and synchronously builds up the pressure to the process base pressure; it supports two independent differential pressure control logics: pressure holding in the upper tank and pressure holding in the lower tank; when a slight leakage occurs in any tank, the corresponding circuit digital valve independently provides slight pressure replenishment, and the casting differential pressure remains constant throughout the entire process; after crystallization is completed, the upper and lower tanks synchronously and in stages release pressure to zero.

[0027] S3-3 Pressure Regulating Casting Vacuum Coupling Process: The PLC controls the pre-vacuum storage tank and the casting tank pipeline to balance for 5 seconds. The vacuum unit simultaneously evacuates the upper and lower tanks to a relative vacuum of -80KPa. The vacuum system continuously maintains a negative pressure environment in the upper tank, while only opening the digital valve group in the lower tank to slowly increase the pressure and form a stable filling pressure difference. Under negative pressure, the aluminum liquid is smoothly lifted and filled into the mold. After shell formation, the upper and lower tanks are simultaneously pressurized to complete the crystallization and pressure holding process.

[0028] The S3-4 pressure-regulating filling and solidification core coupling process: The initial vacuum filling process is consistent with the S3-3 pressure-regulating casting process. After the filling and shell formation processes are completed, the vacuum pipeline is not closed and the vacuum is not broken to release pressure. The PLC fully opens the upper and lower tank dual parallel digital valve groups, and the three 10m³ gas storage tanks release energy synchronously at a large flow rate. High-pressure gas is synchronously introduced into the upper tank's eight DN50 ring branch pipes and the lower tank's DN80 straight main pipe. Relying on the low-resistance structure with no redundant bends or diameter changes in the entire pipeline, the pressurization rate is ≥10KPa / s, and the negative pressure in the tank is increased from -80KPa to 600KPa within 60s. The two sets of digital valves independently and dynamically adjust the gas supply flow of the upper and lower tanks, and lock the process casting pressure difference to remain unchanged throughout the process. The high-pressure environment is maintained for a long time to complete the forced feeding of the casting and eliminate internal porosity defects.

[0029] S3-5 Vacuum Casting Pressurization Coordinated Process: The PLC only starts the upper tank's annular air inlet branch to link the vacuum unit, establishing negative pressure suction in the upper tank; the lower tank's digital valve group continuously replenishes air at a constant pressure to offset the decrease in negative pressure inside the tank caused by the rise of the aluminum liquid; after filling is completed, the dual-path digital valves of the upper and lower tanks are opened simultaneously for rapid pressurization and high-pressure crystallization;

[0030] S3-6 Suspension Casting Collaborative Process: The lower tank's digital valve supplies gas independently, while the upper tank is connected to the atmosphere to maintain normal pressure; four sets of contacts at the bottom, middle, top, and fire escape points of the upper tank collect liquid level signals in real time; a single set of contacts triggers a first-level step-by-step depressurization; when all five sets of contacts are triggered, the system performs an emergency full depressurization to prevent aluminum liquid from overflowing and splashing; the logic of the remaining processes is consistent with that of low-pressure casting.

[0031] S3-7 Upper Tank Inert Protective Atmosphere Differential Pressure Coordination Process: The PLC first controls the gas mixing assembly to output argon mixed protective gas, which is introduced into the tank through the DN125 annular manifold of the upper tank. The vacuum unit simultaneously pumps out the original air in the tank to complete the atmosphere replacement. After the replacement is completed, the digital valve of the upper tank maintains the high-pressure environment of argon gas, and compressed air is introduced into the lower tank to balance the pressure difference between the tanks. The upper tank pressure holding differential pressure logic is used to complete the filling and crystallization.

[0032] According to one embodiment of the present invention, S3-4 includes:

[0033] S3-4-1, Vacuum filling: The pre-vacuum storage tank and the casting tank pipeline are balanced for 5 seconds. The vacuum unit simultaneously evacuates the upper and lower tanks to a relative vacuum of -80KPa. The vacuum maintains the negative pressure in the upper tank, and the digital valve in the lower tank slowly increases the pressure to form a filling pressure difference to complete the aluminum liquid filling.

[0034] S3-4-2, Rapid Pressure Boosting Without Vacuum Breaking: After filling and shelling are completed, the vacuum pipeline is not shut off or pressure is not released; the PLC fully opens the dual parallel digital valve group of the upper and lower tanks, and the three 10m³ gas storage tanks release energy synchronously. High-pressure gas is synchronously introduced into the eight DN50 ring branch pipes of the upper tank and the DN80 straight main pipe of the lower tank. The pipeline eliminates bends and reduces the airflow resistance by changing the diameter. The pressure boosting rate is ≥10KPa / s, and the negative pressure in the tank is increased from -80KPa to 600KPa within 60s; the two sets of digital valves independently adjust the gas supply flow rate and lock the process pressure difference to a constant throughout the process;

[0035] S3-4-3, High Pressure Holding: Continuous pressure holding in a high-pressure environment to complete forced feeding of the casting.

[0036] According to one embodiment of the present invention, both the low-pressure casting and suspension casting processes support dual control modes of pressure filling and flow filling; in the flow filling mode, the gas supply flow rate is constant, eliminating aluminum liquid blowout caused by changes in the cavity cross section; in the pressure filling mode, the pressure control accuracy is ≤0.5KPa.

[0037] According to one embodiment of the present invention, in the suspension casting process, the upper tank is connected to the atmosphere to maintain normal pressure, and the upper tank is equipped with four sets of liquid surface contacts: bottom, middle, top, and fire escape. When a single set of contacts is triggered, a first-level step-by-step depressurization is performed, and when all contacts are triggered simultaneously, an emergency full depressurization of the entire machine is performed.

[0038] According to one embodiment of the present invention, the differential pressure casting includes two differential pressure control logics: upper tank pressure holding and lower tank pressure holding. When any tank leaks a little, the corresponding circuit digital valve independently provides a little pressure replenishment, and the casting differential pressure remains constant throughout the process.

[0039] According to one embodiment of the present invention, the differential pressure process of the upper tank inert protective atmosphere includes an atmosphere replacement step: the PLC controls the gas mixing assembly to output argon mixed protective gas and introduces it into the annular manifold of the upper tank, and the vacuum unit simultaneously pumps out the air in the tank to complete the replacement. After the replacement, the upper tank maintains high argon pressure, and compressed air is introduced into the lower tank to balance the pressure difference.

[0040] According to one embodiment of the present invention, the dual parallel high-speed digital valve groups are hardware redundant, and when one valve group fails, the other valve group independently completes the entire gas supply regulation.

[0041] As can be seen from the above technical solution, the advantages and positive effects of the multi-process anti-gravity dual parallel digital coupling gas supply vacuum coordinated control method of the present invention are as follows:

[0042] This invention integrates the dual parallel digital valve gas supply and pre-vacuum energy storage into a unified and coordinated control system for seven casting processes: low pressure, differential pressure, pressure regulation, pressure regulation filling and solidification, vacuum casting, suspension, and inert protective atmosphere differential pressure. Attached Figure Description

[0043] Various objects, features, and advantages of the invention will become more apparent from the following detailed description of preferred embodiments of the invention, taken in conjunction with the accompanying drawings. The drawings are merely illustrative of the invention and are not necessarily drawn to scale. In the drawings, the same reference numerals always denote the same or similar parts. Wherein:

[0044] Figure 1 This is a 3D overall structural diagram of a dual parallel digital valve pneumatic control system.

[0045] Figure 2 This is a schematic diagram of the control principle of the air-fuel mixing system pipeline.

[0046] Figure 3 This is a schematic diagram of the measured pressure tracking curves throughout the entire process of pressure regulation and pressurization.

[0047] Figure 4 This is a 3D structural schematic diagram of a staged vacuum unit.

[0048] Figure 5 This is a schematic diagram of the layout principle of the compressed air supply system.

[0049] Figure 6 This is a 3D structural diagram of the casting tank.

[0050] Figure 7 This is a schematic diagram of a vacuum system. Detailed Implementation

[0051] To address the shortcomings of existing gas supply and vacuum systems, such as separate control, high pipeline resistance, lack of energy storage buffer, cumbersome process switching, low pressure control accuracy, and numerous casting defects, this invention provides a multi-process anti-gravity dual-parallel digitally coupled gas supply and vacuum collaborative control method. This method relies on a completely isolated dual-path low-resistance annular gas circuit between upper and lower tanks, dual-parallel redundant high-speed digital valve groups, and a dual energy storage hardware carrier consisting of a pre-vacuum tank and a large-capacity gas storage tank. It achieves seamless switching between seven casting processes using a single control logic, with no air-breaking linkage between vacuum and high-pressure gas supply. Rapid pressurization completes high-pressure feeding of the castings, and multi-stage pressure relief via layered liquid surface contacts significantly improves casting quality, shortens production cycle time, and enhances equipment operational safety and continuous production capacity.

[0052] like Figures 1 to 7 As shown, this application provides a multi-process anti-gravity dual-parallel digital coupling gas supply vacuum collaborative control method. The method is executed by an integrated equipment, which includes a casting tank assembly, a dual-parallel high-flow digital valve rapid pressurization gas control assembly, a staged vacuum acquisition assembly, a variable frequency air compressor supply assembly, a multi-component gas mixing protection assembly, and an electrical control assembly.

[0053] The casting tank assembly is equipped with an independent upper tank air inlet branch and an independent lower tank air inlet main pipe. The independent upper tank air inlet branch includes a DN125 annular manifold and eight circumferentially distributed DN50 branch pipes. The independent lower tank air inlet main pipe is a DN80 straight-through stainless steel pipe. The two air paths are physically isolated and have no shared sections.

[0054] The dual-parallel high-flow digital valve high-speed booster pneumatic control assembly includes two sets of mutually redundant FESTO high-speed digital valve groups, with a single valve action response time of 35ms, and is equipped with bottom, middle, top, and fire-running layered contact signal acquisition modules.

[0055] The graded vacuum assembly includes a 10m³ pre-vacuum storage tank 401, a dual rotary vane pump 403 / 404 + 402 Roots pump vacuum unit, and a pre-dust filter 405.

[0056] The variable frequency air compressor supply assembly includes a 75KW variable frequency air compressor 501, three 10m³ parallel high-pressure air storage tanks 502; it also includes a JY-20GF high-temperature refrigerated dryer 503 and a three-stage filter assembly 504.

[0057] The electronic control assembly has a built-in PLC fuzzy PID controller and a 0.1-level differential pressure sensor.

[0058] The cooperative control method includes the following steps:

[0059] S1, Dual-medium pre-energy storage standby control steps

[0060] During the equipment standby phase, the 75KW variable frequency air compressor 501 is started to continuously supply air to the three 10m³ parallel high-pressure air storage tanks 502, and the air storage tanks 502 are stably maintained at a storage pressure of 0.95MPa~1MPa; at the same time, the staged vacuum unit is started to continuously evacuate the 10m³ pre-evacuation vacuum storage tank, and the ultimate absolute pressure of the pre-evacuation tank is stably controlled at ≤50Pa; at this time, all the dual parallel digital valve groups are closed, the upper and lower tank connection valves remain open, and the casting tank is maintained in a normal pressure standby state.

[0061] S2, Tank sealing interlock isolation procedure

[0062] The hoisting and transfer assembly completes the positioning and tank assembly of the middle partition and sand mold. Two φ100 hydraulic locking cylinders tighten the integral forged helical toothed slip-on flange. The cylinder's built-in magnetic ring switch collects the locking signal and transmits it to the PLC. After receiving the sealing signal, the PLC automatically closes the upper and lower tank connecting valves, completely physically isolating the independent upper tank air inlet branch and the independent lower tank air inlet main. The two air paths are individually controlled by two sets of independent parallel digital valve groups. For the overall structure of the digital valve module, please refer to [link to digital valve module description]. Figure 1 As shown.

[0063] S3, Seven Casting Process Mode-Based Coupling and Collaborative Control Steps

[0064] S3-1 Low-Pressure Casting Collaborative Control Process

[0065] The PLC only opens the digital valve group corresponding to the independent lower air intake main pipe, while all the valve groups of the upper tank's annular air intake branch are shut off. The system can switch between pressure filling and flow filling dual control modes. In pressure filling mode, the pressure control accuracy is ≤0.5KPa throughout the process. In flow filling mode, the air supply flow is constant to avoid aluminum liquid blowout caused by changes in the cavity cross section. After the filling, shelling, and crystallization processes are completed, only the lower tank is subjected to staged pressure relief. The tank opening interlock is unlocked after the pressure inside the tank returns to zero.

[0066] S3-2 Differential Pressure Casting Collaborative Control Process

[0067] The PLC synchronously opens the digital valve groups of the upper and lower tanks, and builds up the pressure to the process base pressure. It supports two independent differential pressure control logics: pressure holding in the upper tank and pressure holding in the lower tank. When a slight leakage occurs in any tank, the corresponding digital valve independently provides slight pressure replenishment, and the differential pressure remains constant throughout the casting process. After crystallization, the upper and lower tanks synchronously release pressure in stages to zero.

[0068] S3-3 Pressure Regulating Casting Vacuum Coupling Process

[0069] The PLC controls the pre-vacuum storage tank and the casting tank piping to balance for 5 seconds, relying on... Figure 4 The pneumatic butterfly valve achieves pipeline on / off balance; the vacuum unit simultaneously evacuates the upper and lower tanks to a relative vacuum of -80KPa; the vacuum system continuously maintains a negative pressure environment in the upper tank, and only opens the digital valve group of the lower tank to slowly increase the pressure to form a stable filling pressure difference, and smoothly completes the aluminum liquid filling under negative pressure; after the shell is formed, the upper and lower tanks are simultaneously pressurized to complete the crystallization and pressure holding.

[0070] S3-4 Pressure-regulating filling and pressurized solidification core coupling process (key step of this invention)

[0071] The initial vacuum filling process is consistent with the S3-3 pressure-regulating casting process. After the filling and shell formation processes are completed, the vacuum pipeline is not shut off and the vacuum is not broken to release pressure; the PLC fully opens the upper and lower tank dual parallel digital valve groups. Figure 5 The three gas storage tanks (502) simultaneously release high-pressure gas, which is then simultaneously introduced into the eight DN50 ring branch pipes of the upper tank and the DN80 straight main pipe of the lower tank. Utilizing a low-resistance structure with no unnecessary bends or diameter changes in the entire pipeline, the pressurization rate is ≥10KPa / s, increasing the negative pressure inside the tank from -80KPa to 600KPa within 60 seconds. Two sets of digital valves independently and dynamically regulate the gas supply flow to the upper and lower tanks, maintaining a constant pressure differential during the casting process. This prolonged high-pressure environment ensures forced feeding of the castings, eliminating internal porosity defects. Figure 3 The pressure tracking curve interface is shown.

[0072] S3-5 Vacuum Casting and Pressurization Co-process

[0073] The PLC only activates the upper tank's annular intake branch, which is linked to the vacuum unit, to establish negative pressure suction in the upper tank; the vacuum energy storage unit is... Figure 4 The entire unit features a digital valve group in the lower tank that continuously replenishes gas at a constant pressure to counteract the decrease in negative pressure inside the tank caused by the rise of molten aluminum. After filling is completed, the dual-path digital valves in the upper and lower tanks are opened simultaneously for rapid pressurization and high-pressure crystallization.

[0074] S3-6 Suspension Casting Co-process

[0075] The lower tank's digital valve supplies gas independently, while the upper tank is connected to the atmosphere to maintain normal pressure. The upper tank has four sets of contacts—bottom, middle, top, and fire escape points—that collect liquid level signals in real time. When a single set of contacts is triggered, it performs a first-level pressure relief. When all five sets of contacts are triggered, the system performs an emergency full pressure relief to prevent aluminum liquid from overflowing and splashing. The logic of the remaining processes is the same as that of low-pressure casting.

[0076] S3-7 Upper Tank Inert Protective Atmosphere Differential Pressure Coordination Process

[0077] The PLC first controls the output of argon mixed protective gas from the gas mixing assembly, which is introduced into the tank through the DN125 annular manifold of the upper tank. The vacuum unit simultaneously pumps out the original air in the tank to complete the atmosphere replacement. After the replacement is completed, the digital valve of the upper tank maintains the high-pressure environment of argon gas, and compressed air is introduced into the lower tank to balance the pressure difference between the tanks. The upper tank pressure holding differential pressure logic is used to complete the filling and crystallization.

[0078] S4, Pressure Holding Dynamic Compensation Control Steps

[0079] During the casting pressure holding stage, two sets of 0.1-level high-precision pressure sensors are configured in the upper and lower tanks to collect the circuit pressure in real time. The PLC identifies the leakage of the upper tank circuit and the leakage of the lower tank circuit respectively, and independently controls the corresponding parallel digital valves to automatically replenish pressure in small amounts. The double-layer fluororubber seal ensures that minor leakage will not disrupt the casting pressure difference and ensure the consistency of casting.

[0080] S5, Staged pressure relief and tank opening interlock procedure

[0081] After the casting crystallization and pressure holding process is completed, the PLC performs multi-stage step-by-step pressure relief based on the feedback signal from the layered contact points. First, the high pressure is released and then the pressure difference between the upper and lower tanks is balanced. When the pressure inside the tank stabilizes in the zero pressure range of -2KPa to +2KPa, the system automatically unlocks the hydraulic cylinder can open the tank interlock, and only then can the operation of loosening the tank and lifting the casting be performed.

[0082] The specific process is as follows:

[0083] I. Main Process (Pressure Regulating, Filling, Pressurizing, and Solidification) Step-by-Step Complete Operation + Parameter Control Flow: Stage 1: Equipment Standby Pre-Storage (PLC fully automatic background operation, no manual operation required); PLC triggers the 75KW variable frequency air compressor to start, continuously replenishing air to three 10m³ parallel high-pressure air storage tanks, with a pressure stabilization setting of 0.95~1.0MPa, and automatic pressure replenishment when the pressure is lower than the lower limit; PLC starts the dual rotary vane pump + Roots pump vacuum unit to continuously evacuate air from the 10m³ pre-evacuation energy storage tank, with the ultimate absolute pressure inside the tank stable at ≤50Pa; Electrical status: all dual parallel FESTO digital valve groups are closed, the upper and lower tank connecting valves remain normally open, the casting main tank is on standby at normal pressure, PLC monitors pressure and pump group fault signals in real time, and the valve group is in use with one backup for redundancy.

[0084] Phase 2: Tooling and Mold Closure + Sealing Interlock (Manual Operation + PLC Logic Judgment); The sand mold and partition plate are manually hoisted into the tank, and the upper and lower tanks are closed; the hydraulic locking button is activated, and two φ100 hydraulic cylinders tighten the forged flange; the built-in magnetic ring switch of the hydraulic cylinder transmits a locking signal to the PLC; if no signal is received, all subsequent vacuum and pressurization programs are hardware-interlocked and prohibited from starting; after the PLC receives a qualified signal, it automatically closes the upper and lower tank connecting valves, completing the physical isolation of the two air paths: Upper tank: DN125 annular manifold + 8 circumferential DN50 branch pipes for independent air paths; Lower tank: DN80 straight short pipe for independent air paths; The two paths are controlled independently by two sets of parallel digital valves with PID closed-loop control.

[0085] Phase 3: Negative Pressure Vacuum Filling (PLC Fully Automatic Parameter Closed-Loop Control); The PLC controls the connection between the pre-vacuum storage tank and the casting tank pipeline, with a fixed pressure balancing time of 5 seconds; Subsequently, the vacuum unit synchronously evacuates the upper and lower tanks, with a target relative vacuum of -80 kPa; The upper tank maintains a negative pressure environment throughout the process, only opening the corresponding digital valve in the lower tank, and the PLC switches to the flow filling mode, setting the aluminum liquid rising speed to 95 mm / s to prevent metal liquid blowout in complex cavities; In pressure mode, the pressure control accuracy is ≤0.5 kPa; Real-time acquisition of liquid surface contact signals at the bottom, middle, and top of the mold; When the top contact is triggered, the PLC determines that the filling and shelling processes are complete and proceeds to the next phase.

[0086] Phase 4: Core-level rapid pressurization and solidification without voids (the most innovative step in this patent); Key constraints: The vacuum pipeline remains sealed throughout the entire process without depressurization or voids, preventing air from being drawn into the mold cavity and creating pores; The PLC fully opens the dual parallel redundant digital valve group of the upper and lower tanks, and the three gas storage tanks release energy synchronously at high flow rates, with high-pressure gas being sent to the upper tank's annular multi-point branch pipe and the lower tank's straight main pipe; The pipeline has no bends, a variable diameter and low resistance design, and a pressurization rate ≥10KPa / s, raising the negative pressure inside the tank from -80KPa to 600KPa high pressure within 60 seconds; The PLC uses fuzzy PID to dynamically adjust the opening of the two valves, locking the casting process pressure difference at 25KPa throughout the entire process; Entering the high-pressure holding stage, lasting 12 minutes, the high-pressure extrusion eliminates internal porosity defects in the casting; Redundancy backup: If one set of digital valves fails, the PLC immediately and seamlessly switches to the backup valve group to continue pressurization and holding without stopping the equipment.

[0087] Phase 5: Dynamic compensation closed loop for pressure holding leakage; two 0.1-level high-precision differential pressure sensors in each of the upper and lower tanks transmit pressure data in real time; the PLC calculates the pressure attenuation of the upper and lower loops respectively, and when a slight leakage occurs in the pipeline, it controls the corresponding loop digital valve to make slight gas replenishment; continuously maintain the pressure holding pressure and the casting pressure difference to ensure the consistency of the same batch of castings.

[0088] Phase 6: Staged pressure relief + safety tank opening interlock for finalization; after the pressure holding timer ends, the PLC executes multi-stage step-by-step pressure relief based on the liquid level contact record: first, the high pressure is released, then the internal pressure difference between the upper and lower tanks is balanced; only when the tank pressure stabilizes within the -2KPa to +2KPa zero-pressure range will the PLC unlock the hydraulic cylinder tank-releasing interlock, and tank opening is forcibly prohibited under high pressure; special emergency: if all spark contacts are triggered during the pouring process, the PLC immediately closes all air inlet valves and opens the pressure relief valve for emergency venting of the entire machine to prevent aluminum molten metal splashing accidents; after the pressure returns to zero, the tank is manually opened, the casting is removed, and the single cycle ends.

[0089] II. Simplified control logic for one-click switching of the remaining 6 processes using PLC (one set of programs reused): Low-pressure casting: only the lower tank valve group is supplied with gas, pressure / flow dual modes are selectable, and the lower tank is depressurized separately in stages after filling; Differential pressure casting: the upper and lower tanks are pressurized simultaneously, supporting both upper tank pressure holding and lower tank pressure holding logic, and independent pressure replenishment is provided to maintain the pressure difference in case of leakage; Vacuum suction casting: the upper tank is under negative pressure to draw liquid, and the lower tank provides a small amount of constant pressure gas to offset the negative pressure decay, and dual-path rapid pressurization and crystallization occur after filling; Suspension casting: the upper tank is supplied with atmospheric pressure, and only the lower tank is filled with flow, with step-by-step pressure relief at the liquid surface contact points, and emergency pressure relief in case of fire; Inert atmosphere differential pressure casting: PLC controls argon to replace the air in the tank, with high pressure argon in the upper tank and air in the lower tank to balance the pressure difference for production; Conventional pressure regulating casting: after vacuum filling, the pressure is slightly increased, and the 600KPa extreme rapid pressurization is not performed, which is used for castings with ordinary requirements.

[0090] The present invention has the following beneficial effects:

[0091] This method employs a dual-medium pre-storage system with a pre-vacuum tank and a large-capacity gas storage tank. Vacuum extraction and high-pressure gas supply eliminate the need for real-time waiting for the air compressor and vacuum pump, significantly reducing vacuuming and pressurization time and increasing production cycle time by over 40%. The upper and lower tanks utilize a completely isolated dual-path low-resistance annular gas path with 360° circumferential multi-point synchronous air intake, ensuring a uniform pressure field within the tanks. Combined with dual parallel redundant digital valve groups, the system allows for continuous production without downtime in case of a single valve failure. It achieves continuous coupling control of vacuum negative pressure, high-pressure compressed air, and inert protective gas without cavitation disruption. The pressure-regulating filling and solidification process eliminates intermediate cavitation disruption, significantly reducing porosity and looseness defects in castings and substantially improving the density of thick-walled aluminum alloy castings. The system allows for free switching between pressure and flow filling modes to adapt to complex cavities and prevents filling blowouts. Layered liquid surface contact linkage enables multi-stage automatic pressure relief and automatic protection against fire hazards, greatly improving equipment operational safety. Seven casting processes are integrated into a single collaborative control logic, eliminating the need for manual disassembly of pipelines and valve replacement. The PLC... The automatic switching control program ensures a high degree of automation and adapts to flexible production of castings of various specifications. The pressure control accuracy is ≤0.5KPa for low-pressure / differential-pressure / pressure-regulating processes and ≤2KPa for pressurized solidification stages. The pressure tracks and matches the process setting curve, ensuring stable and controllable casting quality.

[0092] like Figure 1As shown, the pneumatic control system combines two independent pneumatic control systems into a dual-pneumatic control system to achieve multi-functional pneumatic pressure control for the upper and lower tanks. Control modes include: differential pressure casting, low-pressure casting, pressure regulating casting, pressure regulating filling and solidification, vacuum suction casting and solidification, suspension casting, and upper tank protective atmosphere differential pressure casting, among other functions. The pneumatic control system uses a digital valve system, with independent pressure control modes for the upper and lower tanks. The pressure of the upper and lower tanks can be controlled independently, while also achieving linkage control. Differential pressure casting has two control modes: upper tank pressure holding and lower tank pressure holding. The upper tank pressure holding mode effectively prevents the pressure difference from increasing due to leakage in the upper tank, thus preventing uncontrollable pressure holding time. Filling has dual control modes of pressure and flow control, and can also achieve vertical and horizontal bidirectional control by combining pressure control and flow control based on contact signals. The synchronous pressure build-up pressure is adjustable from 0 to 700 kPa, and the synchronous pressure build-up time is ≤10 minutes when the gas source pressure is sufficient. The system measures pressure in kPa, and the unit of measurement is liquid level. The filling speed is measured in mm / s, and the time is measured in seconds. The maximum speed of the system's liquid lifting and filling process reaches 120 mm / s, and the maximum crystallization time is ≥60 minutes. The control system's liquid lifting, filling, and crystallization pressure accuracy is within ≤0.5 kPa, and the pressure holding control accuracy is ≤0.5 kPa. It can stably pressurize when the low-pressure casting gas source pressure is ≥0.4 MPa, and can stably pressurize when the differential pressure casting gas source pressure is ≥0.7 MPa. Vacuum filling and pressurized solidification can stably pressurize when the gas source pressure is ≥0.9 MPa. A low-pressure casting mode is reserved for a mold vacuuming function. If vacuuming is required later for low-pressure casting, a vacuum pump can be added to achieve casting and vacuuming linkage (an independent vacuum pump, not shared with the vacuum system).

[0093] like Figure 2 As shown, the protective gas achieves dual functions of pressurization and melting through secondary pressurization after gas mixing. Multiple gas selection options are available for different functional gas requirements via solenoid valves and flow meters. The advantages of using a gas booster pump for secondary pressurization compared to a mechanical booster pump include fewer leakage points, longer service life, and lower failure rate. The system selects various gases to first enter the mixing chamber for thorough mixing before pressurization by the booster pump. Different protective gases are selected to enter different containers via solenoid valves. Pressure sensors are designed for each protective gas with different functions, allowing users to set the required pressure. Automatic pressure replenishment can be selected (replenishment is required for continuous production; one mixing cycle is sufficient for single production). The equipment is designed with a differential pressure casting function for the upper tank with a protective atmosphere. Initially, argon is introduced into the upper tank to establish an inert atmosphere. To prevent the pressure in the upper tank from being too high compared to the lower tank, pressurized protective gas is used in the lower tank to balance the pressure in the upper tank, simultaneously creating a protective film on the surface of the molten metal. During the later differential pressure filling process, compressed air is used in the lower tank, while argon continues to be used in the upper tank for pressure maintenance. The measured pressure tracking curve of the entire pressure regulation, filling, and pressurization process is shown below. Figure 3 As shown.

[0094] like Figure 4 As shown, the vacuum system consists of two sets of rotary vane pumps, a Roots pump, and a vacuum storage tank. It features fast pumping speed and high vacuum. The vacuum system design utilizes a shared pressure-regulating, pressurized solidification device and a digital vacuum pressurization device. The rotary vane pumps are 300 cubic meters per hour, and the Roots pumps are 1800 cubic meters per hour. The ultimate vacuum of the rotary vane pumps is 50 Pa, and that of the Roots pumps is 8*10⁻² Pa. A 10 cubic meter vacuum tank is used. A pre-filter is added before the vacuum pump set to filter out dust evacuated from the furnace. Vacuum system switching is achieved via a pneumatic butterfly valve, which can be used under both positive and negative pressure conditions. The main evacuation pipeline is DN100, and all valves on the pipeline are also DN100 diameter valves.

[0095] like Figure 5 As shown, the air compressor system consists of three parts: an air compressor, air receiver tanks, and a refrigerated drying and filtration system. The air compressor is a variable frequency screw air compressor with a maximum outlet pressure of 1.05 MPa and a flow rate of 11 cubic meters per minute. Three 10-cubic-meter air receiver tanks are selected, with a pressure rating of 1.32 MPa. The refrigerated drying and filtration system is configured with a flow rate of 20 cubic meters per minute and features a three-stage filtration system: one stage before the refrigerated dryer and two stages at the dryer outlet.

[0096] The following descriptions are provided in conjunction with specific embodiments:

[0097] Example 1: Complete and coordinated control process for pressure-regulated filling and solidification

[0098] This control method is used to execute the pressure regulating filling and pressurized solidification process, and all hardware parameters adopt the standard configuration in the tender document:

[0099] 1. Pre-stored energy standby: such as Figure 5 As shown, the 75KW air compressor continuously stabilizes the pressure of the three 10m³ air storage tanks at 0.98MPa; the dual rotary vane pump + Roots vacuum unit works continuously, stabilizing the 10m³ pre-evacuation tank at 42Pa absolute pressure, with all dual parallel FEST digital valves closed and the tank connection valve open.

[0100] 2. Tank Sealing: The central partition automatically lowers and centers, the hydraulic cylinder pulls and locks the flange, a magnetic ring switch transmits the locking signal, the PLC closes the upper and lower tank connecting valve, and the upper and lower air circuits are physically separated, such as... Figure 1 As shown.

[0101] 3. Vacuum filling: The pressure of the pre-drawing tank and the casting tank is balanced for 5 seconds, such as... Figure 4As shown, the vacuum unit synchronously pumps the tank to -80KPa; the upper tank maintains negative pressure, and the digital valve of the lower tank slowly increases the pressure to form a filling pressure difference of 25KPa. The flow mode controls the rising speed of the aluminum liquid to 95mm / s for stable filling. The top contact of the mold triggers the determination that the filling is complete.

[0102] 4. Rapid pressurization without vacuum disruption: The vacuum pipeline remains sealed. Figure 4 The butterfly valve is not closed. Figure 1 Both sets of digital valves are fully open. Figure 5 The gas storage tank supplies gas synchronously. The pressure is increased from -80KPa to 600KPa in 52 seconds, with a pressurization rate of 11.2KPa / s. The two valves are adjusted in real time to maintain a constant casting pressure difference of 25KPa throughout the process. The high-pressure holding time is 12 minutes to complete the feeding.

[0103] 5. Staged pressure relief: After the pressure holding is completed, the high pressure is released slowly first, and then the pressure in the upper and lower tanks is balanced. After 32 seconds, the pressure in the tank stabilizes at ±1KPa. The system unlocks the tank opening interlock, and the hoisting mechanism lifts the upper tank to remove the casting.

[0104] The actual pressure curve measured on site is shown in Figure 3. The set pressure and the actual pressure curve completely coincide. The pressure control error throughout the process is ≤0.4KPa. There are no loose or porosity defects inside the casting.

[0105] Example 2: Differential Pressure Control Process for Inert Protective Atmosphere in Upper Tank

[0106] 1. The pre-energy storage standby procedure is the same as in Example 1;

[0107] 2. The tank is sealed and isolated from two independent gas paths;

[0108] 3. The PLC controls the output of argon protective gas from the gas mixing system; gas blending relies on... Figure 2 Mixing pipeline; the gas is introduced into the upper tank through a DN125 ring manifold branch pipe, and the vacuum unit simultaneously extracts the air in the tank to complete the atmosphere replacement;

[0109] 4. After the replacement is completed, the digital valve in the upper tank maintains a high argon pressure of 280 kPa, and compressed air is introduced into the lower tank to balance the pressure difference. The entire process of filling, shell formation, and crystallization is completed using the pressure-holding mode of the upper tank.

[0110] 5. After the process is completed, the pressure is released in stages to zero, and the can is unlocked and opened.

[0111] Example 3: Safety Control Procedure for Suspension Casting

[0112] 1. The pre-storage and tank isolation procedures are the same as in Example 1;

[0113] 2. The upper tank is connected to atmospheric pressure, while the lower tank receives digital gas supply only, using a flow-based filling mode; the gas supply valve body and contact module are all located within... Figure 1 Pneumatic control cabinet;

[0114] 3. In the mold filling process, when the liquid level triggers the contacts at the bottom and in the mold, the system performs small-step pressure relief stage by stage; if the liquid level reaches the run-out contact at the top of the mold, all 5 groups of contacts are triggered, the system automatically fully opens the pressure relief valve for emergency pressure relief, so as to prevent safety accidents caused by aluminum liquid splashing.

[0115] Figure 1 In the present invention, the pneumatic control system adopts two sets of independent pneumatic control systems combined into a dual pneumatic control system to realize multi-functional pneumatic pressure control for the upper and lower crucibles. Control modes include various functions such as differential pressure casting, low pressure casting, pressure regulation, pressure-regulated filling and pressure solidification, vacuum suction casting, suspension, and differential pressure casting with protective atmosphere in the upper crucible. The pneumatic control system adopts digital valves for independent pressure control of the upper and lower crucibles. The pressure of the upper and lower crucibles can be controlled independently, and linkage control can be realized at the same time. Mold filling has dual control modes of pressure and flow; synchronous pressure building is adjustable from 0 to 700KPa, the maximum mold filling speed is 120mm / s, and the pressure control accuracy is ≤0.5KPa.

[0116] Figure 2 In the present invention, the gas mixing pipeline is provided with multiple groups of argon, SF6, and CO2 gas supply branches, equipped with flowmeters, pressure regulating valves, mixing chambers, booster pumps, and double-volume gas storage tanks, which can independently blend different protective gases for smelting and inert atmosphere casting in the upper crucible.

[0117] Figure 3 In the present invention, the pressure curve of the whole pressure regulating casting process is monitored in real time, and the set pressure, actual pressure, equipment timing and indicator light status are displayed synchronously.

[0118] Figure 4 In the present invention, the negative pressure environment for casting is quickly established by the pre-vacuum tank 401, Roots pump 402, rotary vane pumps 403 / 404, and filter 405.

[0119] Figure 5 In the present invention, the variable frequency air compressor 501 continuously stabilizes the pressure for three gas storage tanks 502, and the gas is sent through the switching valve to the attached Figure 1 pneumatic control cabinet after passing through the refrigerated dryer 503 and three-stage filter 504, so as to meet the demand for large-flow gas source for extreme rapid pressurization.

[0120] Figure 6The lower tank intake uses a DN80 pipe for direct air intake. The upper tank intake uses eight DN50 pipes passing through the lower tank flange and entering the upper tank, then converging through a DN125 ring pipe. The upper tank's main intake pipe is a DN80 pipe, with an overall cross-sectional area larger than the eight DN50 pipes, ensuring sufficient air supply and reducing air resistance. The locking mechanism uses a hydraulic ring locking mechanism. Both the upper tank seal and the middle partition seal use φ25mm fluororubber sealing rings with double sealing, creating two sealed spaces between the upper and lower tanks and the middle partition. The hydraulic locking cylinder uses two Ф100 cylinders for locking. The locking ring uses a helical tooth locking structure, with the helical teeth of the locking ring engaging with the helical teeth of the upper tank via the hydraulic cylinder. The clearance between the locking ring and the lower tank flange is 2mm, and the fit accuracy between the locking ring and the upper tank flange is 5mm, ensuring the coaxiality of the locking ring and guaranteeing smooth closing of the upper and lower tanks. The locking ring presses the upper tank, which in turn presses down on the middle partition. The seal is achieved through the sealing rings between the flanges of the upper and lower tanks and between the middle partition and the flange of the lower tank. In this way, the upper and lower tanks and the middle partition are combined to form two sealed containers.

[0121] Figure 7 The vacuum system consists of two sets of rotary vane pumps, a Roots pump, and a vacuum storage tank. It features rapid pumping speed and high vacuum levels. The system design utilizes a shared pressure-regulating, pressurized solidification device and a digital vacuum pressurization device. The rotary vane pumps are 300 cubic meters per hour, and the Roots pumps are 1800 cubic meters per hour. The ultimate vacuum of the rotary vane pumps is 50 Pa, and that of the Roots pumps is 8 × 10⁻² Pa. A 10 cubic meter vacuum tank is used. A pre-filter is added before the vacuum pump set to remove dust evacuated from the furnace. Vacuum system switching is achieved via pneumatic butterfly valves, which can be used under both positive and negative pressure conditions. The main evacuation pipeline is DN100, and all valves on the pipeline are also DN100 diameter valves.

[0122] Those skilled in the art should understand that the specific structures and processes shown in the above detailed embodiments are merely exemplary and not restrictive. Furthermore, those skilled in the art can combine the various technical features described above in various possible ways to form new technical solutions or make other modifications, all of which fall within the scope of this invention.

Claims

1. A multi-process anti-gravity dual-parallel digitally coupled gas supply vacuum coordinated control method, characterized in that: The method is performed using integrated casting equipment, which includes a casting tank assembly, a dual parallel high-flow digital valve rapid pressurization pneumatic control assembly, a staged vacuum acquisition assembly, a variable frequency air compressor supply assembly, a multi-component gas mixing protection assembly, and an electrical control assembly. The casting tank assembly is equipped with an independent upper tank air inlet branch and an independent lower tank air inlet main branch; The dual parallel high-flow digital valve high-speed booster pneumatic control assembly includes two sets of mutually redundant FESTO high-speed digital valve groups, with a single valve action response time of 35ms, and is equipped with bottom, middle, top, and fire-running layered contact signal acquisition modules. The graded vacuum assembly includes a 10m³ pre-vacuum storage tank and a dual rotary vane pump + Roots pump vacuum unit. The variable frequency air compressor supply assembly includes a 75KW variable frequency air compressor and three 10m³ parallel high-pressure air storage tanks; The electronic control assembly incorporates a PLC fuzzy PID controller and a 0.1-level differential pressure sensor. The cooperative control method includes the following steps: S1. Dual-medium pre-energy storage standby control steps: During the equipment standby phase, the 75KW variable frequency air compressor continuously supplies air to the three 10m³ parallel high-pressure air storage tanks, and the air storage tank pressure is stabilized at 0.95MPa-1MPa; the staged vacuum unit continuously evacuates the 10m³ pre-evacuation vacuum energy storage tank, and the absolute pressure of the pre-evacuation tank is ≤50Pa; all dual parallel digital valve groups are closed, the upper and lower tank connection valves are opened, and the tank is in standby at normal pressure; S2, Tank sealing interlock isolation steps: The hydraulic locking cylinder pulls the flange, and the magnetic ring switch transmits the locking signal to the PLC; After receiving the signal, the PLC closes the upper and lower tank connection valve, physically isolating the independent upper tank air inlet branch and the independent lower tank air inlet main branch. The two air routes are controlled by two sets of independent parallel digital valve groups respectively. S3, Seven casting processes are coupled and coordinated in different modes, including seven independent control processes: low pressure, differential pressure, pressure regulation, pressure regulation filling and pressurization solidification, vacuum casting, suspension, and inert protective atmosphere differential pressure. S4. Pressure holding dynamic compensation control steps: During the pressure holding stage, the pressure sensors of the upper and lower tanks collect the circuit pressure in real time, and the PLC independently identifies the leakage of the upper and lower tanks and controls the corresponding digital valves to automatically compensate for the pressure in a small amount. S5. Staged pressure relief and tank opening interlock steps: After crystallization is completed, the PLC layered contact signal executes multi-stage pressure relief. After the tank pressure stabilizes in the range of -2KPa to +2KPa, the tank opening interlock is unlocked.

2. The multi-process anti-gravity dual parallel digital coupling gas supply vacuum coordinated control method according to claim 1, characterized in that: S3 includes: S3-1 Low-Pressure Casting Collaborative Control Process: The PLC only opens the digital valve group corresponding to the independent lower air intake main pipe, while all valve groups of the upper tank's annular air intake branch are shut off; the system can switch between pressure filling and flow filling dual control modes. In pressure filling mode, the pressure control accuracy is ≤0.5KPa throughout the process, while in flow filling mode, the air supply flow is constant to avoid aluminum liquid blowout caused by changes in the cavity cross-section; after the filling, shelling, and crystallization processes are completed, only the lower tank is subjected to staged pressure relief, and the tank opening interlock is unlocked after the pressure inside the tank returns to zero; S3-2 Differential Pressure Casting Collaborative Control Process: The PLC synchronously opens the digital valve groups of the upper and lower tanks, and synchronously builds up the pressure to the process base pressure; it supports two independent differential pressure control logics: pressure holding in the upper tank and pressure holding in the lower tank; when a slight leakage occurs in any tank, the corresponding circuit digital valve independently provides slight pressure replenishment, and the casting differential pressure remains constant throughout the entire process; after crystallization is completed, the upper and lower tanks synchronously and in stages release pressure to zero. S3-3 Pressure Regulating Casting Vacuum Coupling Process: The PLC controls the pre-vacuum storage tank and the casting tank pipeline to balance for 5 seconds. The vacuum unit simultaneously evacuates the upper and lower tanks to a relative vacuum of -80KPa. The vacuum system continuously maintains a negative pressure environment in the upper tank, while only opening the digital valve group in the lower tank to slowly increase the pressure and form a stable filling pressure difference. Under negative pressure, the aluminum liquid is smoothly lifted and filled into the mold. After shell formation, the upper and lower tanks are simultaneously pressurized to complete the crystallization and pressure holding process. The S3-4 pressure-regulating filling and solidification core coupling process: The initial vacuum filling process is consistent with the S3-3 pressure-regulating casting process. After the filling and shell formation processes are completed, the vacuum pipeline is not closed and the vacuum is not broken to release pressure. The PLC fully opens the upper and lower tank dual parallel digital valve groups, and the three 10m³ gas storage tanks release energy synchronously at a large flow rate. High-pressure gas is synchronously introduced into the upper tank's eight DN50 ring branch pipes and the lower tank's DN80 straight main pipe. Relying on the low-resistance structure with no redundant bends or diameter changes in the entire pipeline, the pressurization rate is ≥10KPa / s, and the negative pressure in the tank is increased from -80KPa to 600KPa within 60s. The two sets of digital valves independently and dynamically adjust the gas supply flow of the upper and lower tanks, and lock the process casting pressure difference to remain unchanged throughout the process. The high-pressure environment is maintained for a long time to complete the forced feeding of the casting and eliminate internal porosity defects. S3-5 Vacuum Casting Pressurization Coordinated Process: The PLC only starts the upper tank's annular air inlet branch to link the vacuum unit, establishing negative pressure suction in the upper tank; the lower tank's digital valve group continuously replenishes air at a constant pressure to offset the decrease in negative pressure inside the tank caused by the rise of the aluminum liquid; after filling is completed, the dual-path digital valves of the upper and lower tanks are opened simultaneously for rapid pressurization and high-pressure crystallization; S3-6 Suspension Casting Collaborative Process: The lower tank's digital valve supplies gas independently, while the upper tank is connected to the atmosphere to maintain normal pressure; four sets of contacts at the bottom, middle, top, and fire escape points of the upper tank collect liquid level signals in real time; a single set of contacts triggers a first-level step-by-step depressurization; when all five sets of contacts are triggered, the system performs an emergency full depressurization to prevent aluminum liquid from overflowing and splashing; the logic of the remaining processes is consistent with that of low-pressure casting. S3-7 Upper Tank Inert Protective Atmosphere Differential Pressure Coordination Process: The PLC first controls the gas mixing assembly to output argon mixed protective gas, which is introduced into the tank through the DN125 annular manifold of the upper tank. The vacuum unit simultaneously pumps out the original air in the tank to complete the atmosphere replacement. After the replacement is completed, the digital valve of the upper tank maintains the high-pressure environment of argon gas, and compressed air is introduced into the lower tank to balance the pressure difference between the tanks. The upper tank pressure holding differential pressure logic is used to complete the filling and crystallization.

3. The multi-process anti-gravity dual parallel digital coupling gas supply vacuum coordinated control method according to claim 2, characterized in that: S3-4 includes: S3-4-1, Vacuum filling: The pre-vacuum storage tank and the casting tank pipeline are balanced for 5 seconds. The vacuum unit simultaneously evacuates the upper and lower tanks to a relative vacuum of -80KPa. The vacuum maintains the negative pressure in the upper tank, and the digital valve in the lower tank slowly increases the pressure to form a filling pressure difference to complete the aluminum liquid filling. S3-4-2, Rapid Pressure Boosting Without Vacuum Breaks: After filling and shelling are completed, the vacuum pipeline is not shut off or pressure is not released; the PLC fully opens the dual parallel digital valve group of the upper and lower tanks, and the three 10m³ gas storage tanks release energy synchronously. High-pressure gas is synchronously introduced into the eight DN50 ring branch pipes of the upper tank and the DN80 straight main pipe of the lower tank. The pipeline eliminates bends and reduces airflow resistance by changing diameter. The pressure boosting rate is ≥10KPa / s, and the negative pressure in the tank is increased from -80KPa to 600KPa within 60s; the two sets of digital valves independently adjust the gas supply flow rate, and the process pressure difference is locked constant throughout the process; S3-4-3, High Pressure Holding: Continuous pressure holding in a high-pressure environment to complete forced feeding of the casting.

4. The multi-process anti-gravity dual parallel digital coupling gas supply vacuum coordinated control method according to claim 1, characterized in that: Both the low-pressure casting and suspension casting processes support dual control modes of pressure filling and flow filling; in the flow filling mode, the gas supply flow is constant, eliminating aluminum liquid blowout caused by changes in the cavity cross section; in the pressure filling mode, the pressure control accuracy is ≤0.5KPa.

5. The multi-process anti-gravity dual parallel digital coupling gas supply vacuum coordinated control method according to claim 4, characterized in that: In the suspension casting process, the upper tank is connected to the atmosphere to maintain normal pressure. The upper tank is equipped with four sets of liquid surface contacts: bottom, middle, top, and fire escape. When a single set of contacts is triggered, a first-level pressure relief is performed. When all contacts are triggered at the same time, an emergency full pressure relief of the entire machine is performed.

6. The multi-process anti-gravity dual parallel digital coupling gas supply vacuum coordinated control method according to claim 5, characterized in that: The differential pressure casting includes two differential pressure control logics: upper tank pressure holding and lower tank pressure holding. When any tank leaks a little, the corresponding circuit digital valve independently provides a little pressure replenishment, and the casting differential pressure remains constant throughout the process.

7. The multi-process anti-gravity dual parallel digital coupling gas supply vacuum coordinated control method according to claim 6, characterized in that: The differential pressure process of the inert protective atmosphere in the upper tank includes an atmosphere replacement step: the PLC controls the gas mixing assembly to output argon mixed protective gas and introduces it into the annular manifold of the upper tank. The vacuum unit simultaneously pumps out the air in the tank to complete the replacement. After replacement, the upper tank maintains high argon pressure, and compressed air is introduced into the lower tank to balance the pressure difference.

8. The multi-process anti-gravity dual parallel digital coupling gas supply vacuum coordinated control method according to claim 1, characterized in that: The dual parallel high-speed digital valve groups provide hardware redundancy for each other. In the event of a failure in one valve group, the other valve group can independently complete the entire gas supply regulation.

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