Blowoff device and method of operation suitable for additive manufacturing internal flow channels

Abstract

This invention provides a blowing device and operating method suitable for internal flow channels in additive manufacturing. The device includes a gas source, a blowing path, a pressurization path, a liquid flow path, a cleaning fluid container, a filter, a 3D printed product containing internal flow channels, and a controller. The output end of the gas source is connected to the input ends of both the blowing path and the pressurization path. The pressurization path, the cleaning fluid container, and the liquid flow path are connected sequentially. The output ends of both the blowing path and the liquid flow path are connected to the input end of the filter, but the blowing path and the liquid flow path are not simultaneously connected to the filter. The output end of the filter is connected to the input end of the 3D printed product containing internal flow channels. This invention uses a circulating gas-liquid mixing blowing method combining liquid immersion and gas blowing to ensure that both upstream and downstream of the internal flow channel maintain high pressure during the blowing process, while also ensuring significant impact, shearing, and wedging forces on the inner wall of the flow channel. This effectively ensures the blowing, detection, and removal of particulate matter, powdery waste, and adhering substances.

Description

Technical Field

[0001] This invention relates to the field of spacecraft propulsion technology, and more specifically, to a blowing device and operating method suitable for internal flow channels in additive manufacturing. Background Technology

[0002] Additive manufacturing technology is suitable for manufacturing complex structures and is beginning to be widely used in aerospace engine manufacturing and modular design of propulsion systems. Compared to traditional machinery industries, in the field of aerospace propulsion technology, the internal channels of additively manufactured structures are in prolonged contact with highly corrosive and toxic propellants. The slag buildup in these internal channels can become movable debris under the influence of medium flow impact, corrosion, and flight vibration, leading to catastrophic consequences such as leaks and catalyst bed contamination. The inherent characteristics of additive manufacturing processes inevitably result in slag buildup in the internal channels.

[0003] Due to the complexity, high flow resistance, and numerous bends in the flow channels of engines and propulsion systems, traditional cleaning processes are insufficient to remove them. CN 115570151A discloses a method for cleaning and inspecting the internal flow channels of a 3D-printed aluminum alloy engine mounting bracket, which combines high-pressure gas blowing, abrasive flow, high-pressure liquid flow, and ultrasonic treatment. However, due to mechanistic limitations, high-pressure gas blowing, vibration cleaning, and ultrasonic treatment are not ideal for removing slag adhering to the engine walls. Small-sized foreign matter and adhesives that cannot be detected by gas blowing may become foreign matter due to propellant corrosion during in-orbit flight, flowing with the propellant and clogging the engine head, contaminating the catalyst. Abrasive flow can embed itself in materials such as aluminum alloys, forming new foreign matter. When cleaning the flow channels with acid or alkali solutions, both react with the aluminum in the aluminum alloy, resulting in residual silicon and its oxidation, which becomes new adhesive. High-pressure liquid flushing is the most effective method, but the internal flow channel has a small orifice diameter (as small as sub-millimeter), many bends, and high flow resistance. Pressure loss reaches more than half when the liquid reaches the middle and rear of the channel, resulting in ineffective purging. Furthermore, the inlet pressure is generally limited to no more than 3.5 MPa due to structural strength constraints of the engine or propulsion system, limiting its practical application. Additionally, the patented detection method cannot detect adhering substances using gas purging, CT scans cannot distinguish tiny foreign objects in the internal flow channel, and vibration tests cannot simulate the scouring effect of propellant on the wall during actual on-orbit operation.

[0004] The devices disclosed in patents such as CN208261851U, CN117818047 A, and CN119657948 A are all based on the principle of vibration powder removal, which cannot solve the problem of excess material in the internal flow channels of spacecraft propulsion systems in additive manufacturing.

[0005] Therefore, it is necessary to overcome the shortcomings of existing technologies and provide a blowing device and operation method suitable for the internal flow channels of additive manufacturing, so as to solve the problem of incomplete cleaning of slag in the internal flow channels of existing additive manufacturing products, thereby eliminating problems such as leakage and catalyst contamination caused by foreign matter from additive manufacturing entering the propellant. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a blowing device and operating method suitable for internal flow channels in additive manufacturing.

[0007] According to the present invention, a blowing device suitable for internal flow channels in additive manufacturing includes: a gas source, a blowing path, a pressurization path, a liquid flow path, a cleaning fluid container, a filter, a 3D printed product containing internal flow channels, and a controller, wherein the controller is electrically connected to the blowing path and the pressurization path or connected to the driving gas respectively.

[0008] The output end of the gas source is connected to the input ends of the purging path and the pressurization path, respectively. The pressurization path, the cleaning fluid container, and the liquid flow path are connected in sequence. The output ends of both the purging path and the liquid flow path are connected to the input end of the filter, but the purging path and the liquid flow path are not simultaneously connected to the filter. The output end of the filter is connected to the input end of the 3D printed product containing the internal flow channel. The output end of the 3D printed product is connected to the foreign matter detection device.

[0009] Preferably, the gas source outlet is connected to a first pressure gauge and a first ball valve, and the gas stored inside the gas source includes: high-pressure nitrogen or compressed air.

[0010] Preferably, the purging path includes, in sequence: a first pressure reducing valve, a second pressure gauge, a purging control valve, and a check valve, wherein the input end of the first pressure reducing valve is connected to the output end of the first ball valve, and the purging control valve is connected in parallel with the second ball valve.

[0011] Preferably, the pressurization circuit includes, in sequence, a second pressure reducing valve, a third pressure gauge, and a third ball valve, wherein the input end of the second pressure reducing valve is connected to the output end of the first ball valve, and the third ball valve is connected to the gas end of the cleaning fluid container.

[0012] Preferably, the gas end of the cleaning fluid container is connected to a fourth pressure gauge, the cleaning fluid container is provided with a cleaning fluid filling and draining port, and the cleaning fluid in the cleaning fluid container includes: deionized water or analytical grade anhydrous ethanol.

[0013] Preferably, the fluid flow path includes a fourth ball valve and a fluid flow control valve, wherein the fourth ball valve is connected to the liquid end of the cleaning fluid container, and the fluid flow control valve is connected in parallel with a fifth ball valve.

[0014] Preferably, the controller is connected to the purging control valve and the liquid flow control valve via a cable or a drive air line.

[0015] Preferably, the maximum pressure of both the purging path and the liquid flow path does not exceed the verification pressure of the 3D printed product containing the inner flow channel, and the gas flow rate is between 10-100m / s.

[0016] Preferably, the output end of the filter is connected to the input end of the 3D printed product containing the internal flow channel via an adapter, and the filter has a filtration accuracy of 5-25μm.

[0017] An operating method for a blowing device suitable for internal flow channels in additive manufacturing, provided by the present invention, includes the following steps: Step S1: Open the first ball valve, adjust the output pressure of the first pressure reducing valve to P1, and the output pressure of the second pressure reducing valve to P2; Step S2: Open the third ball valve and the fourth ball valve; Step S3: The liquid flow control valve is opened to completely immerse the flow channel of the 3D printed product containing the inner flow channel, and then closed. After an interval of t3, the blow-out control valve is opened to completely blow out the liquid in the flow channel of the 3D printed product containing the inner flow channel, and then closed. Step S4: During the blowing process, a dust-free wiping cloth is wrapped around the outlet of the 3D printed product containing the inner flow channel, or foreign matter is checked using a foreign matter detection device. If the foreign matter check result does not meet the standard, steps S3-S4 are repeated until the foreign matter check result meets the standard, and the operation ends.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention combines the advantages of high-pressure gas purging and liquid flow through a circulating gas-liquid mixing purging method that uses liquid immersion and gas purging. This ensures that both upstream and downstream of the inner flow channel maintain high pressure during the purging process, while also ensuring a large impact force, shear force, and wedging effect on the inner wall of the flow channel. This effectively ensures the removal of defects, slag, and other particulate matter, while also ensuring the detection and removal of powdery excess material and adhesives.

[0019] 2. This invention employs a gas-liquid mixed blowing state for cleanroom cloth inspection, simulating the actual on-orbit working process. Compared to inspection in liquid or gaseous states, the inspection effect is more effective. The automatic gas-liquid mixed blowing device can be programmed to operate automatically, saving time and manpower. Furthermore, the optimal powder removal effect can be achieved by adjusting the valve opening and closing sequence according to the flow channel size and configuration of different products. Combined with traditional ultrasonic cleaning, compressed air blowing, high-pressure water washing, alkaline washing, abrasive flow, and vibration combined powder removal methods, this invention serves as the final step in the processing and inspection, better detecting and removing adhering excess materials. Attached Figure Description

[0020] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram illustrating the structure of a blowing device suitable for internal flow channels in additive manufacturing, which is the main feature of this invention.

[0021] The diagram shows: air source 1, first pressure gauge 2, first ball valve 3, controller 4, filter 5, adapter 6, 3D printed product with internal flow channel 7, foreign matter detection device 8, first pressure reducing valve 11, second pressure gauge 12, second ball valve 13, purge control valve 14, check valve 15, second pressure reducing valve 21, third pressure gauge 22, third ball valve 23, fourth ball valve 31, fifth ball valve 32, liquid flow control valve 33, cleaning fluid container 41, and fourth pressure gauge 42. Detailed Implementation

[0022] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0023] like Figure 1 As shown, a blowing device for additive manufacturing internal channels provided by the present invention includes: an air source 1, a blowing path, a pressurizing path, a liquid flow path, a cleaning fluid container 41, a filter 5, a 3D printed product 7 containing internal channels, and a controller 4. The controller 4 is electrically connected to the blowing path and the pressurizing path or connected to the driving air. The output end of the air source 1 is connected to the input end of the blowing path and the pressurizing path. The pressurizing path, the cleaning fluid container 41, and the liquid flow path are connected in sequence. The output ends of the blowing path and the liquid flow path are both connected to the input end of the filter 5, but the blowing path and the liquid flow path are not simultaneously connected to the filter 5. The output end of the filter 5 is connected to the input end of the 3D printed product 7 containing internal channels. The output end of the 3D printed product 7 is connected to a foreign matter detection device 8.

[0024] The outlet of gas source 1 is connected to a first pressure gauge 2 and a first ball valve 3. Gas source 1 is used to store gas for pressurization and purging. The gas stored inside gas source 1 includes high-pressure nitrogen or compressed air.

[0025] The purging path includes, in sequence: a first pressure reducing valve 11, a second pressure gauge 12, a purging control valve 14, and a check valve 15. The input end of the first pressure reducing valve 11 is connected to the output end of the first ball valve 3. The purging control valve 14 is connected in parallel with the second ball valve 13. The outlet of the check valve 15 is connected to the inlet of the filter 5.

[0026] The pressurization circuit includes, in sequence: a second pressure reducing valve 21, a third pressure gauge 22, and a third ball valve 23. The input end of the second pressure reducing valve 21 is connected to the output end of the first ball valve 3, and the third ball valve 23 is connected to the gas end of the cleaning fluid container 41.

[0027] The cleaning fluid container 41 is connected to a fourth pressure gauge 42 at the gas end. The cleaning fluid container 41 is provided with a cleaning fluid filling and drain outlet. The cleaning fluid in the cleaning fluid container 41 includes deionized water or analytical grade anhydrous ethanol.

[0028] The fluid flow path includes: a fourth ball valve 31 and a fluid flow control valve 33. The fourth ball valve 31 is connected to the liquid end of the cleaning fluid container 41. The fluid flow control valve 33 is connected in parallel with a fifth ball valve 32. The outlet of the fourth ball valve 31 is connected to the fifth ball valve 32 and the fluid flow control valve 33. After the fifth ball valve 32 and the fluid flow control valve 33 are connected in parallel, their outlets are connected to the inlet of the filter 5.

[0029] The controller 4 is connected to the purge control valve 14 and the liquid flow control valve 33 via a cable or a drive air line, and can realize automatic control of the opening and closing of the purge control valve 14 and the liquid flow control valve 33.

[0030] The maximum pressure of both the purging path and the liquid flow path does not exceed the verification pressure of the 3D printed product 7 containing the internal flow channel, and the gas flow rate is between 10-100m / s.

[0031] The output end of filter 5 is connected to the input end of 3D printed product 7 containing internal flow channels via adapter 6. The filtration accuracy of filter 5 is 5-25μm.

[0032] An operating method for a blowing device suitable for internal flow channels in additive manufacturing, provided by the present invention, includes the following steps: Step S1: Open the first ball valve 3, adjust the output pressure of the first pressure reducing valve 11 to P1, and the output pressure of the second pressure reducing valve 21 to P2. P1 and P2 are mainly subject to the verification pressure. The higher the better, the better the purging effect and the faster the filling. Step S2: Open the third ball valve 23 and the fourth ball valve 31; In step S3, the liquid flow control valve 33 is opened to completely immerse the flow channel of the 3D printed product 7 containing the inner flow channel, and then closed. After an interval of t3, the blow-out control valve 14 is opened to completely blow out the liquid in the flow channel of the 3D printed product 7 containing the inner flow channel, and then closed. In step S4, during the blowing process, a dust-free wiping cloth is wrapped around the outlet of the flow channel of the 3D printed product 7 containing the inner flow channel or foreign matter is checked by the foreign matter detection device 8. If the foreign matter inspection result does not meet the standard, steps S3-S4 are repeated until the foreign matter inspection result meets the standard, and the operation ends.

[0033] More specifically, in step S3, an automatic control program is set as follows: the opening time t1 of the liquid flow control valve 33 is set according to the flow channel length to ensure that the cleaning fluid can completely immerse the flow channel; the opening time t2 of the purge control valve 14 is set according to the flow channel length to ensure that the gas output from the gas source 1 can completely purge the liquid in the flow channel; the interval time t3 is set according to the flow channel length and the actual purge effect to ensure that the cleaning fluid can wet the flow channel and prevent the gas output from the gas source 1 from being blown into the cleaning fluid container 41; and the program termination time t4 is set according to the flow channel length and the actual purge effect. The valve action sequence is as follows: the liquid flow control valve 33 is opened for t1 time and then closed; after an interval of t3 time, the purge control valve 14 is opened for t2 time and then closed; the above steps are repeated for t4 time, after which the program terminates, and the liquid flow control valve 33 and the purge control valve 14 remain closed.

[0034] Furthermore, the complete immersion time needs to be determined based on factors such as the complexity and inner diameter of the piping system. This can be estimated using the pipe length and diameter. For example, by briefly filling the liquid path and observing liquid flowing out of the outlet of the 3D printed product containing the inner flow channel (channel 7), the filling time is recorded as t1. The interval time t3 is determined based on whether immersion is required. If there is no immersion requirement, an interval of 1 second is used to avoid timing confusion caused by opening the gas and liquid valves simultaneously. If immersion is required, the interval is determined based on actual needs. The complete purging time is also determined based on factors such as the complexity and inner diameter of the piping system. This can be estimated using the pipe length and diameter. For example, by briefly purging the air path and observing no liquid flowing out of the outlet of the 3D printed product containing the inner flow channel (channel 7), the purging time is recorded as t2.

[0035] All components of this application are connected by conduits and connectors. The second ball valve 13 and the fifth ball valve 32 are used as test valves. For example, to determine the purging time mentioned above, the control valve can be opened manually to allow gas and liquid to flow downstream without the controller controlling the control valve.

[0036] This application is described in detail using the following data. In one embodiment, the cleaning fluid added to the cleaning fluid container 41 is deionized water, the gas source 1 is high-pressure nitrogen, the design pressure of the 3D printed product with internal flow channels is 2MPa, the verification pressure is 3MPa, the material is aluminum alloy, the filter 5 has a filtration accuracy of generally 15μm, and the controller 4 controls the blow-off control valve 14 and the liquid flow control valve 33 via cable. The 3D printed product 7 with internal flow channels first undergoes vibration cleaning, high-pressure gas blowing, acid and alkali cleaning of the flow channels, high-pressure liquid flow, and ultrasonic treatment before undergoing gas-liquid mixing blowing. After gas-liquid mixing blowing, the 3D printed product 7 with internal flow channels is vacuum dried.

[0037] The operating method of the blowing device suitable for the internal flow channel of additive manufacturing includes the following steps: Step S1: Open the first ball valve 3, adjust the output pressure of the first pressure reducing valve 11 to 3MPa, and the output pressure of the second pressure reducing valve 21 to 2MPa; Step S2: Open the third ball valve 23 and the fourth ball valve 31; Step S3, Automatic Control Program Settings: Set the opening time of the liquid flow control valve 33 to 5s. This time is set according to the flow channel length to ensure that the deionized water can completely immerse the flow channel. Set the opening time of the purge control valve 14 to 15s. This time is set according to the flow channel length to ensure that the high-pressure nitrogen can completely purge the liquid in the flow channel. Set the interval time to 1s. This time is set according to the flow channel length and the actual purge effect to ensure that the deionized water can wet the flow channel and prevent the high-pressure nitrogen from being blown into the cleaning liquid container 41. Set the program termination time to 1000s. This time is set according to the flow channel length and the actual purge effect. The valve action sequence is as follows: the liquid flow control valve 33 is opened for 5s and then closed. After an interval of 1s, the purge control valve 14 is opened for 15s and then closed. The above steps are repeated for 1000s and the program terminates. The liquid flow control valve 33 and the purge control valve 14 remain closed. Step S4: After the foreign matter detection device 8 has not detected any foreign matter for more than 30 seconds during the blowing process, wrap a dust-free wiping cloth around the outlet of the flow channel of the 3D printed product 7 containing the inner flow channel and observe it with a 30x magnifying glass. There should be no foreign matter visible to the naked eye.

[0038] From the perspective of practical engineering applications, this application combines the advantages of high-pressure gas purging and liquid flow through a circulating gas-liquid mixed purging method that combines liquid immersion with gas purging. This ensures that both upstream and downstream of the inner flow channel maintain high pressure during the purging process, while also ensuring a large impact force, shear force, and wedging effect on the inner wall of the flow channel. This effectively ensures the removal of defects, slag, and other particulate matter, while also ensuring the detection and removal of powdery excess material and adhesives.

[0039] When performing foreign matter detection, this application employs a gas-liquid mixed blowing state for cleanroom cloth inspection. The inspection process simulates the actual on-orbit working process, which is more effective than inspection in liquid or gaseous states. The automatic gas-liquid mixed blowing device of this application can operate automatically according to the program settings, saving time and manpower. Furthermore, it can achieve the best powder removal effect by adjusting the valve opening and closing sequence according to the flow channel size and configuration of different products. This application can be combined with traditional ultrasonic cleaning, compressed air blowing, high-pressure water washing, alkaline washing, abrasive flow, and vibration combined powder removal methods as the final step in treatment and inspection, for better detection and removal of adhering foreign matter.

[0040] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "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 application 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 application.

[0041] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A blowing device and method for internal flow channels in additive manufacturing, characterized in that, include: The gas source (1), the purging path, the pressurization path, the liquid flow path, the cleaning fluid container (41), the filter (5), the 3D printed product (7) containing the internal flow channel, and the controller (4), wherein the controller (4) is electrically connected to the purging path and the pressurization path or connected to the driving gas respectively; The output end of the gas source (1) is connected to the input ends of the purging path and the pressurizing path respectively. The pressurizing path, the cleaning fluid container (41) and the liquid flow path are connected in sequence. The output ends of the purging path and the liquid flow path are both connected to the input end of the filter (5). The purging path and the liquid flow path are not connected to the filter (5) at the same time. The output end of the filter (5) is connected to the input end of the 3D printed product (7) with the internal flow channel. The output end of the 3D printed product (7) is connected to the foreign matter detection device (8).

2. The blowing device for additive manufacturing internal channels as described in claim 1, characterized in that, The outlet of the gas source (1) is connected to a first pressure gauge (2) and a first ball valve (3). The gas stored inside the gas source (1) includes high-pressure nitrogen or compressed air.

3. The blowing device for additive manufacturing internal channels as described in claim 2, characterized in that, The purging path includes, in sequence: a first pressure reducing valve (11), a second pressure gauge (12), a purging control valve (14), and a check valve (15). The input end of the first pressure reducing valve (11) is connected to the output end of the first ball valve (3), and the purging control valve (14) is connected in parallel with a second ball valve (13).

4. The blowing device for additive manufacturing internal channels as described in claim 2, characterized in that, The pressurization circuit includes, in sequence: a second pressure reducing valve (21), a third pressure gauge (22), and a third ball valve (23). The input end of the second pressure reducing valve (21) is connected to the output end of the first ball valve (3), and the third ball valve (23) is connected to the gas end of the cleaning fluid container (41).

5. The blowing device for additive manufacturing internal channels as described in claim 1, characterized in that, The cleaning fluid container (41) is connected to a fourth pressure gauge (42) at the gas end. The cleaning fluid container (41) is provided with a cleaning fluid filling and drain outlet. The cleaning fluid in the cleaning fluid container (41) includes: deionized water or analytical grade anhydrous ethanol.

6. The blowing device for additive manufacturing internal channels as described in claim 3, characterized in that, The fluid flow path includes a fourth ball valve (31) and a fluid flow control valve (33). The fourth ball valve (31) is connected to the liquid end of the cleaning fluid container (41), and the fluid flow control valve (33) is connected in parallel with a fifth ball valve (32).

7. The blowing device for additive manufacturing internal channels as described in claim 6, characterized in that, The controller (4) is connected to the purge control valve (14) and the liquid flow control valve (33) via a cable or a drive air line.

8. The blowing device for additive manufacturing internal channels as described in claim 1, characterized in that, The maximum pressure of both the purging path and the liquid flow path does not exceed the verification pressure of the 3D printed product (7) containing the internal flow channel, and the gas flow rate is between 10-100m / s.

9. The blowing device for additive manufacturing internal channels as described in claim 1, characterized in that, The output end of the filter (5) is connected to the input end of the 3D printed product (7) with internal flow channel via an adapter (6), and the filter (5) has a filtration accuracy of 5-25μm.

10. A method of operating the blowing device for internal flow channels in additive manufacturing as described in any one of claims 1-9, characterized in that, Includes the following steps: Step S1: Open the first ball valve (3), adjust the output pressure of the first pressure reducing valve (11) to P1, and the output pressure of the second pressure reducing valve (21) to P2; Step S2: Open the third ball valve (23) and the fourth ball valve (31); Step S3, the liquid flow control valve (33) is opened to completely immerse the flow channel of the 3D printed product (7) containing the inner flow channel and then closed. After an interval of t3, the blow-out control valve (14) is opened to completely blow out the liquid in the flow channel of the 3D printed product (7) containing the inner flow channel and then closed. Step S4: During the blowing process, a dust-free wiping cloth is wrapped around the outlet of the 3D printed product (7) containing the inner flow channel or foreign matter is checked by a foreign matter detection device (8). If the foreign matter check result does not meet the standard, steps S3-S4 are repeated until the foreign matter check result meets the standard and the operation ends.

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