Hot gas bulging forming gas source and working method thereof

Abstract

The invention discloses a hot gas bulging forming gas source and a working method thereof, and the hot gas bulging forming gas source comprises a gas using unit for providing bulging inert gas for a workpiece in a hot gas bulging mold; the low-pressure gas storage unit is used for storing low-pressure inert gas and is communicated to the gas utilization unit through a main gas pump; and the recycling loop is communicated between the gas using unit and the gas inlet pipeline of the low-pressure gas storage unit and can recycle inert gas in the workpiece. According to the invention, the residual gas in the bulging process is recovered, so that the emptying loss is reduced, and the material cost is saved.

Description

Technical Field

[0001] This invention relates to the field of hot gas expansion molding technology, and in particular to a hot gas expansion molding gas source and its working method. Background Technology

[0002] Hot gas expansion forming is an advanced manufacturing technology that uses high-temperature gas pressure to expand and shape metal sheets or tubes within a mold. It combines the characteristics of thermoforming and pneumatic forming and is suitable for processing complex curved parts. It involves heating a hollow tube to a certain temperature and then internally filling it with high-pressure gas to achieve internal expansion. This technology has been widely used in automotive A-pillars, B-pillars, torsion beams, crash beams, and rear towing beams. The hot gas expansion forming process generally includes bending, laser marking, pre-forming, heating, and expansion processes.

[0003] Currently, inert gases such as nitrogen are used in the bulging process to apply high pressures of tens of megapascals, softening the material and causing it to conform to the mold cavity to form the desired shape. However, in existing production processes, the nitrogen stored in the workpiece cavity is often directly vented after bulging, resulting in waste, especially for workpieces with large cavities where nitrogen waste is more severe.

[0004] To overcome the above problems, a hot air expansion molding air source and its working method are needed. Summary of the Invention

[0005] The purpose of this invention is to provide a hot gas expansion forming gas source and its working method, which recovers residual gas in the expansion forming process, reduces exhaust loss, and saves material costs.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] The hot gas expansion molding air source of the present invention includes:

[0008] The gas supply unit provides inert gas for expansion of the workpiece inside the hot gas expansion mold;

[0009] A low-pressure gas storage unit is used to store low-pressure inert gas and connect it to the gas-using unit through a main gas pump;

[0010] The recovery circuit, connected between the gas-using unit and the low-pressure gas storage unit's inlet pipeline, is capable of recovering inert gas from the workpiece.

[0011] Existing hot gas expansion molding equipment uses an venting method to release residual nitrogen gas from the workpiece cavity, which is wasteful and also increases the nitrogen concentration in the work area, posing a safety hazard to workers. Recovering and reusing residual nitrogen gas would be of great significance.

[0012] Furthermore, the low-pressure gas storage unit includes multiple gas storage cylinders connected in parallel on the main pipeline, and an inlet shut-off valve and an outlet shut-off valve are respectively installed at both ends of the main pipeline; an overflow valve and a pressure measuring component are also installed on the main pipeline.

[0013] Furthermore, the pressure measuring component includes a barometer and a pressure sensor, and the pressure sensor feeds back the pressure signal to the equipment's electrical control system.

[0014] Furthermore, the low-pressure gas storage unit also includes a venting branch, which includes an exhaust shut-off valve and a muffler connected in series, with the exhaust shut-off valve's inlet connected to the main pipeline.

[0015] The low-pressure gas storage unit is designed reasonably to ensure a sufficient supply of nitrogen raw material when the main gas pump is working.

[0016] Furthermore, it also includes a liquid nitrogen vaporization unit, the output of which is connected to the inlet pipe of the low-pressure gas storage unit.

[0017] Furthermore, it also includes a high-pressure gas storage unit, a first gas valve and a second gas valve. The first gas valve is connected in series on the output pipeline of the main gas pump, and the second gas valve is connected in series on the output pipeline of the high-pressure gas storage unit. The outputs of the first gas valve and the second gas valve are connected to the gas-using unit.

[0018] The high-pressure gas storage unit is designed to quickly fill the inner cavity of the workpiece with high-pressure nitrogen, thus preventing the red-hot workpiece from cooling down when the main gas pump cannot supply enough nitrogen quickly when the inner cavity of the workpiece is large, which would lead to failure of hot gas expansion molding.

[0019] Furthermore, the recovery circuit includes a fourth gas valve, a recovery gas pump, and a recovery check valve. The fourth gas valve is connected in series between the input end of the recovery gas pump and the gas-using unit, and the recovery check valve is located between the output end of the recovery gas pump and the inlet pipeline of the low-pressure gas storage unit.

[0020] Furthermore, the recovery circuit also includes a recovery gas storage unit, a third gas valve, and a sixth gas valve. The sixth gas valve is connected between the fourth gas valve and the low-pressure gas storage unit. The recovery gas storage unit is connected to the third gas valve through a pipeline. The other end of the third gas valve is connected between the sixth gas valve and the fourth gas valve.

[0021] Furthermore, this invention employs a pilot control loop to control the switching of the operating states of the first, second, third, fourth, fifth, and sixth air valves. This significantly improves operational safety and stability.

[0022] The present invention also discloses a method for operating a hot gas expansion molding gas source, wherein a high-pressure inert gas is supplied to the workpiece that needs to be hot gas expanded molding using any of the above-mentioned hot gas expansion molding gas sources; the inert gas remaining in the mold cavity after the expansion molding is completed can be recycled by the recovery circuit.

[0023] Furthermore, by adding a gas recovery and storage unit, the high-pressure residual inert gas stored in the inner cavity of the workpiece is released quickly, thereby improving the recovery speed.

[0024] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0025] This invention provides a hot gas expansion forming gas source that, by adding the aforementioned recovery circuit, can recover and reuse the inert gas remaining inside the workpiece after hot gas expansion forming, reducing venting losses and saving gas material costs. By arranging two gas-using units side by side, inert gas can be supplied to two workpieces simultaneously during hot gas expansion forming.

[0026] Furthermore, a larger gas storage capacity can be achieved by connecting multiple gas cylinders in parallel. The addition of an overflow valve reduces the risk of high-pressure damage. The venting branch, consisting of an exhaust shut-off valve and a silencer, allows for the removal of residual gas from the gas cylinders during maintenance and repair. The addition of a high-pressure gas storage unit stores some of the excess nitrogen output from the main gas pump. This high-pressure nitrogen is then output to the gas-using unit along with the main gas pump the moment the second gas valve opens, reducing filling time and enabling rapid hot gas expansion molding, preventing the workpiece from being cooled by the mold cavity wall before expansion. The addition of a fourth gas valve, which connects or closes the recovery circuit, achieves isolation between the recovery circuit after hot gas expansion and the hot gas expansion process. By adding a gas recovery and storage unit, after the thermal expansion process is completed, the high-pressure nitrogen gas inside the workpiece cavity is connected. This nitrogen gas travels along the pipeline through the sixth and third gas valves into the gas storage cylinder of the gas recovery and storage unit, where the pressure is rapidly released. The majority of the gas is recovered and stored in the gas recovery and storage unit, thus increasing the recovery rate and allowing for faster production cycles. All gas valves on the main circuit are pilot-operated pneumatic control valves, suitable for controlling high pressure with low pressure, and offer good safety. Flow valves are installed in the pilot gas control branch to adapt to the required pilot gas flow rate, ensuring smooth and reliable operation.

[0027] The hot gas expansion forming gas source working method of the present invention realizes the rapid recovery of high-pressure residual inert gas stored in the inner cavity of the workpiece through the gas absorption and extraction process of the gas storage unit, ensuring the recovery speed and recovery ratio; at the same time, it avoids the continuous operation of the recovery gas pump for a long time. Attached Figure Description

[0028] The present invention will be further described below with reference to the accompanying drawings.

[0029] Figure 1 This is a schematic diagram of the gas source and gas path for hot gas expansion molding of the present invention;

[0030] Figure 2 This is a schematic diagram of the gas path of the low-pressure gas storage unit in the hot gas expansion forming gas source of the present invention;

[0031] Figure 3 This is the pilot control gas path diagram of the present invention.

[0032] Explanation of reference numerals in the attached diagram: 1. Low-pressure gas storage unit; 101. Inlet shut-off valve; 102. Outlet shut-off valve; 103. Pressure gauge; 104. Pressure sensor; 105. Overflow valve; 106. Exhaust shut-off valve; 107. Silencer; 108. Gas storage cylinder; 2. Main air pump; 3. First air valve; 4. Gas consumption unit; 401. Hot gas expansion mold; 402. Actuating cylinder; 403. Filter; 5. High-pressure gas storage unit; 6. Second air valve; 7. Return gas storage unit; 8. Third air valve; 9. Fourth air valve; 10. Recovery air pump; 11. Recovery check valve; 12. Liquid nitrogen vaporization unit; 13. Fifth air valve; 14. Sixth air valve; 15. Pilot air valve; 16. Flow valve; 17. Pilot air shut-off valve; 18. Pilot air filter; 19. Pilot air pressure reducing valve. Detailed Implementation

[0033] The core of this invention is to provide a hot gas expansion forming gas source and its working method, which recovers residual gas in the expansion forming process, reduces exhaust loss, and saves material costs.

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0036] Refer to the attached diagram. Figure 1 This is a schematic diagram of the gas source and gas path for hot gas expansion molding of the present invention; Figure 2 This is a schematic diagram of the gas path of the low-pressure gas storage unit in the hot gas expansion forming gas source of the present invention; Figure 3 This is the pilot control gas path diagram of the present invention.

[0037] In one specific implementation, such as Figures 1-3 As shown, the hot gas expansion forming gas source of the present invention, gas supply unit 4, provides inert gas for expansion of the workpiece inside the hot gas expansion mold 401. The gas supply unit 4 also includes an action cylinder 402, a filter 403, and a cooler. The air inlet pipe passes through the filter 403 and the cooler, and then through the plug at the working end of the action cylinder 402 to connect to the inner cavity of the workpiece inside the hot gas expansion mold 401.

[0038] The low-pressure gas storage unit 1 is used to store low-pressure inert gas and is connected to the gas consumption unit 4 through the main gas pump 2. That is, the main gas pump 2 draws inert gas from the low-pressure gas storage unit 1, pressurizes it and supplies it to the gas consumption unit 4.

[0039] The recovery circuit, connected between the gas-using unit 4 and the inlet pipe of the low-pressure gas storage unit 1, can recover and reuse the inert gas remaining in the workpiece.

[0040] After the current expansion process is completed, the inert gas remaining in the inner cavity of the workpiece is directly vented and released as the piston rod end plugs disengage from both ends of the workpiece, resulting in waste.

[0041] Specifically, such as Figure 1 As shown, there are two sets of air-using units 4, which are arranged side by side on the worktable of the hot air expansion molding machine and connected in parallel.

[0042] Specifically, such as Figure 1 As shown, a one-way valve and a fifth gas valve 13 are connected in series between the low-pressure gas storage unit 1 and the main gas pump 2. The one-way valve prevents the inert gas from impacting back.

[0043] This application, by adding the aforementioned recovery circuit, enables the recovery and reuse of inert gas remaining inside the workpiece after hot gas expansion molding, reducing venting losses and saving gas material costs. By arranging two gas-using units 4 side by side, inert gas can be supplied to two workpieces simultaneously during hot gas expansion molding.

[0044] In one specific embodiment of the present invention, such as Figure 1 and Figure 2 As shown, the low-pressure gas storage unit 1 includes multiple gas cylinders 108 connected in parallel on the main pipeline. An inlet shut-off valve 101 and an outlet shut-off valve 102 are respectively installed at both ends of the main pipeline. An overflow valve 105 and a pressure measuring assembly are also installed on the main pipeline.

[0045] Specifically, such as Figure 1 and Figure 2As shown, the gas cylinders 108 have a specification of 40MPa-50L and a quantity of 10. The overflow valve 105 is set to a working gas pressure of 40MPa. The inlet shut-off valve 101 and the outlet shut-off valve 102 can be manual valves or electrically controlled valves.

[0046] Specifically, such as Figure 2 As shown, the pressure measuring component includes a barometer 103 and a pressure sensor 104, with the pressure sensor 104 feeding back a pressure signal to the equipment's electrical control system. The barometer 103 has a pressure rating of 0–40 MPa. Type E. The barometric pressure sensor 104 has a measurement range of 0–40 MPa, an accuracy of 0.5% FS, and an output signal of 4–20 mA.

[0047] Specifically, such as Figure 2 As shown, the low-pressure gas storage unit 1 also includes a venting branch, which includes an exhaust shut-off valve 106 and a muffler 107 connected in series. The air inlet of the exhaust shut-off valve 106 is connected to the main pipeline.

[0048] A larger gas storage capacity can be obtained by connecting multiple gas cylinders 108 in parallel. The risk of high pressure damage is reduced by adding an overflow valve 105. The venting branch consisting of an exhaust shut-off valve 106 and a silencer 107 can be used to discharge residual gas in the gas cylinders 108 during maintenance and repair.

[0049] In one specific embodiment of the present invention, such as Figure 1 As shown, the hot gas expansion forming gas source of the present invention also includes a liquid nitrogen vaporization unit 12, the output end of which is connected to the inlet pipe of the low-pressure gas storage unit 1. A one-way valve is connected in series on the output end of the liquid nitrogen vaporization unit 12. That is, nitrogen is used as the inert gas for hot gas expansion forming in the present invention.

[0050] Specifically, such as Figure 1 As shown, the specifications of the liquid nitrogen vaporization unit 12 are 300 Nm3 / H, 350 bar, 55 KW, and 380 VAC. When the pressure of the low-pressure gas storage unit 1 is lower than 200 bar, the liquid nitrogen pump of the liquid nitrogen vaporization unit 12 starts to work and outputs nitrogen to the low-pressure gas storage unit 1. When the pressure is higher than 350 bar, it stops working.

[0051] In one specific embodiment of the present invention, the hot gas expansion forming gas source further includes a high-pressure gas storage unit 5, a first gas valve 3, and a second gas valve 6. The first gas valve 3 is connected in series in the output pipeline of the main gas pump 2, and the second gas valve 6 is connected in series in the output pipeline of the high-pressure gas storage unit 5. The outputs of the first gas valve 3 and the second gas valve 6 are connected to the gas-using unit 4. A one-way valve is also connected in series at the output end of the first gas valve 3 to prevent gas diversion.

[0052] Specifically, the main structure of the high-pressure gas storage unit 5 is the same as that of the low-pressure gas storage unit 1, which also includes multiple gas cylinders 108 connected in parallel on the main pipeline, except that its working gas pressure is 70MPa.

[0053] By adding a high-pressure gas storage unit 5, some of the excess nitrogen output from the main gas pump 2 can be stored. The high-pressure nitrogen can be output to the gas-using unit 4 together with the main gas pump 2 at the moment the second gas valve 6 is opened, reducing the inflation time and allowing the hot gas expansion molding to be completed quickly in a short time, avoiding the workpiece being cooled by the cavity wall of the hot gas expansion mold 401 before expansion.

[0054] In one specific embodiment of the present invention, such as Figure 1 As shown, the recovery circuit includes a fourth gas valve 9, a recovery gas pump 10, and a recovery check valve 11. The fourth gas valve 9 is connected in series between the input end of the recovery gas pump 10 and the gas-using unit 4, and the recovery check valve 11 is located between the output end of the recovery gas pump 10 and the air inlet pipeline of the low-pressure gas storage unit 1.

[0055] By adding a fourth gas valve 9, the recovery circuit can be connected or closed to achieve the isolation between the connection recovery after the thermal expansion and the thermal expansion.

[0056] Specifically, such as Figure 1 As shown, the recovery circuit also includes a recovery gas storage unit 7, a third gas valve 8, and a sixth gas valve 14. The sixth gas valve 14 is connected between the fourth gas valve 9 and the low-pressure gas storage unit 1. The recovery gas storage unit 7 is connected to the third gas valve 8 through a pipeline. The other end of the third gas valve 8 is connected between the sixth gas valve 14 and the fourth gas valve 9.

[0057] Specifically, the main structure of the gas recovery and storage unit 7 is the same as that of the high-pressure gas storage unit 5, which also includes multiple gas cylinders 108 connected in parallel on the main pipeline, except that its working gas pressure is 10MPa.

[0058] By adding a gas recovery and storage unit 7, after the thermal expansion is completed, the inner cavity of the workpiece is connected. The high-pressure nitrogen in the inner cavity of the workpiece enters the gas storage cylinder 108 of the gas recovery and storage unit 7 through the sixth gas valve 14 and the third gas valve 8 along the pipeline. The gas pressure is released quickly, and most of it is recovered into the gas recovery and storage unit 7 first. This improves the recovery rate and can match a faster production cycle.

[0059] In one specific embodiment of the present invention, such as Figure 3 As shown, the first air valve 3, the second air valve 6, the third air valve 8, the fourth air valve 9, the fifth air valve 13, and the sixth air valve 14 are all pilot-operated pneumatic control valves, controlled by a pilot control circuit. The pilot control circuit includes at least six parallel pilot gas control branches, each pilot gas control branch controlling one of the aforementioned pilot-operated pneumatic control valves.

[0060] Specifically, such as Figure 3 As shown, the pilot gas control branch includes a pilot gas valve 15 and a flow valve 16 connected in series, and the pilot gas valve 15 is a solenoid directional valve.

[0061] Specifically, such as Figure 3 As shown, the pilot control circuit has a pilot air shut-off valve 17, a pilot air filter 18, and a pilot air pressure reducing valve 19 connected in series on the main pipeline.

[0062] All the gas valves in the main circuit are pilot-operated pneumatic control valves, which are suitable for controlling high pressure with low pressure and have good safety. By installing flow valve 16 in the pilot gas control branch, the required pilot gas flow can be adapted, and the operation is smooth and reliable.

[0063] In summary, the hot gas expansion forming gas source of the present invention, by adding the recovery circuit, can recover and reuse the inert gas remaining in the workpiece after hot gas expansion forming, reducing venting losses and saving gas material costs. By arranging the two gas-using units 4 side by side, inert gas can be supplied to the hot gas expansion forming of two workpieces simultaneously. In addition, the parallel connection of multiple gas storage cylinders 108 can obtain a large gas storage capacity, and the addition of the overflow valve 105 reduces the risk of high pressure damage; the addition of the venting branch consisting of the exhaust shut-off valve 106 and the silencer 107 allows the residual gas in the gas storage cylinders 108 to be discharged during maintenance and repair. By adding the high-pressure gas storage unit 5, some of the excess nitrogen output from the main gas pump 2 can be stored. The high-pressure nitrogen can be output to the gas-using unit 4 together with the main gas pump 2 at the moment the second gas valve 6 is opened, reducing the filling time and allowing the hot gas expansion forming to be completed quickly in a short time, avoiding the workpiece being cooled by the cavity wall of the hot gas expansion mold 401 before expansion. By adding a fourth gas valve 9, the recovery circuit can be connected or closed to achieve isolation between the recovery process after the thermal expansion is completed and the thermal expansion process itself. By adding a recovery gas storage unit 7, after the thermal expansion is completed, the workpiece cavity is connected, and the high-pressure nitrogen gas inside the workpiece cavity flows along the pipeline through the sixth gas valve 14 and the third gas valve 8 into the gas storage cylinder 108 of the recovery gas storage unit 7. The gas pressure is rapidly released, and most of it is recovered first into the recovery gas storage unit 7, thus improving the recovery rate and matching a faster production cycle. All gas valves on the main circuit are pilot-operated pneumatic control valves, suitable for controlling high pressure with low pressure, and offer good safety. By installing a flow valve 16 in the pilot gas control branch, the required pilot gas flow rate can be adapted, ensuring smooth and reliable operation.

[0064] This invention also discloses a method for operating a hot gas expansion molding gas source, which uses any of the hot gas expansion molding gas sources described in the above embodiments to supply high-pressure inert gas to the workpiece requiring hot gas expansion molding. The inert gas remaining in the mold cavity after expansion molding can be recovered and reused by the recovery circuit.

[0065] Specifically, the hot gas expansion forming gas source working method of the present invention improves the recovery speed and ensures a high-efficiency production cycle by adding a gas recovery and storage unit to quickly release the high-pressure residual inert gas stored in the inner cavity of the workpiece.

[0066] The hot gas expansion forming gas source working method of the present invention realizes the rapid recovery of high-pressure residual inert gas stored in the inner cavity of the workpiece by recovering the gas storage unit through the gas intake and gas extraction process, ensuring the recovery speed and recovery ratio; at the same time, it avoids the continuous operation of the recovery gas pump for a long time.

[0067] The hot gas expansion molding air source working method of the present invention specifically includes the following steps:

[0068] S1, air supply: At this time, the heated workpiece is installed in the hot air expansion mold 401, and both ends of the workpiece are sealed by the plugs at the working end of the actuating cylinder 402. The fifth air valve 13 and the first air valve 3 are connected, the main air pump 2 starts to work, draws inert gas from the low-pressure air storage unit 1, pressurizes it and supplies it to the air-using unit 4, which then enters the inner cavity of the workpiece.

[0069] S2. Gas replenishment: Synchronized with step S1, the second gas valve 6 is opened. The high-pressure nitrogen stored in the high-pressure gas storage unit 5 is output to the gas-using unit 4 along with the main gas pump 2 the moment the second gas valve 6 opens, reducing the inflation time and allowing the hot gas expansion molding to be completed quickly in a short time. In the later stage of molding and pressure holding, the high-pressure nitrogen output by the main gas pump 2 also enters the gas storage cylinder 108 of the high-pressure gas storage unit 5 through the second gas valve 6, replenishing the high-pressure gas storage unit 5.

[0070] S3. After the nitrogen is recovered and the holding time is reached, the hot gas expansion molding is completed. At this time, the main air pump 2 stops working, and the first air valve 3, the second air valve 6, and the fifth air valve 13 are closed. The third air valve 8 and the sixth air valve 14 are opened. The high-pressure nitrogen in the inner cavity of the workpiece enters the gas storage cylinder 108 of the recovery and storage unit 7 through the pipeline and the connected sixth air valve 14 and third air valve 8. The gas pressure is released rapidly, and most of the nitrogen is recovered to the recovery and storage unit 7 first.

[0071] S4. The residual nitrogen is vented, the sixth gas valve 14 is closed, the actuating cylinder 402 retracts, the plug at the end of the piston rod disengages from both ends of the workpiece, and a small amount of residual nitrogen is directly vented and released.

[0072] S5, nitrogen circulation, the fourth gas valve 9 opens, the recovery gas pump 10 starts working, the nitrogen in the recovery storage unit 7 flows back to the inlet pipeline of the low-pressure storage unit 1 through the third gas valve 8, the fourth gas valve 9, the recovery gas pump 10 and the recovery check valve 11, and merges with the nitrogen output from the liquid nitrogen vaporization unit 12 and enters the low-pressure storage unit 1 together.

[0073] After the next set of workpieces is re-installed into the hot air expansion mold 401, the hot air expansion molding air source of the present invention begins to cycle again according to the above working steps.

[0074] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0075] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A hot air expansion molding air source, characterized in that, include: The gas supply unit (4) provides inert gas for expansion of the workpiece inside the hot gas expansion mold (401); A low-pressure gas storage unit (1) is used to store low-pressure inert gas and is connected to the gas-using unit (4) through a main gas pump (2); The recovery circuit is connected between the gas supply unit (4) and the low-pressure gas storage unit (1) inlet pipe, and can recover the inert gas in the workpiece.

2. The hot gas expansion molding gas source according to claim 1, characterized in that: The low-pressure gas storage unit (1) includes multiple gas storage cylinders (108) connected in parallel on the main pipeline. An inlet shut-off valve (101) and an outlet shut-off valve (102) are respectively provided at both ends of the main pipeline. An overflow valve (105) and a pressure measuring component are also provided on the main pipeline.

3. The hot gas expansion molding gas source according to claim 2, characterized in that: The pressure measuring component includes a barometer (103) and a pressure sensor (104), and the pressure sensor (104) feeds back the pressure signal to the equipment's electrical control system.

4. The hot gas expansion molding gas source according to claim 2, characterized in that: The low-pressure gas storage unit (1) also includes a venting branch, which includes an exhaust shut-off valve (106) and a silencer (107) connected in series. The air inlet of the exhaust shut-off valve (106) is connected to the main pipeline.

5. The hot gas expansion molding gas source according to claim 1, characterized in that: It also includes a liquid nitrogen vaporization unit (12), the output of which is connected to the inlet pipe of the low-pressure gas storage unit (1).

6. The hot gas expansion molding gas source according to claim 1, characterized in that: It also includes a high-pressure gas storage unit (5), a first gas valve (3) and a second gas valve (6). The first gas valve (3) is connected in series on the output pipeline of the main gas pump (2), and the second gas valve (6) is connected in series on the output pipeline of the high-pressure gas storage unit (5). The output of the first gas valve (3) and the second gas valve (6) is connected to the gas-using unit (4).

7. The hot gas expansion molding gas source according to claim 1, characterized in that: The recovery circuit includes a fourth gas valve (9), a recovery gas pump (10), and a recovery check valve (11). The fourth gas valve (9) is connected in series between the input end of the recovery gas pump (10) and the gas-using unit (4). The recovery check valve (11) is located between the output end of the recovery gas pump (10) and the air inlet pipeline of the low-pressure gas storage unit (1).

8. The hot gas expansion molding gas source according to claim 7, characterized in that, The recovery circuit also includes a recovery gas storage unit (7), a third gas valve (8) and a sixth gas valve (14). The sixth gas valve (14) is connected between the fourth gas valve (9) and the low-pressure gas storage unit (1). The recovery gas storage unit (7) is connected to the third gas valve (8) through a pipeline. The other end of the third gas valve (8) is connected between the sixth gas valve (14) and the fourth gas valve (9).

9. A method for using a hot air expansion molding air source, characterized in that: The hot gas expansion forming gas source according to any one of claims 1 to 8 is used to supply high-pressure inert gas to the workpiece that needs to be hot gas expanded; the inert gas remaining in the cavity after the expansion is completed can be recycled by the recovery circuit.

10. The hot gas expansion molding gas source working method according to claim 9, characterized in that, By adding a gas recovery and storage unit, the high-pressure residual inert gas stored in the inner cavity of the workpiece is released quickly, thus improving the recovery speed.

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