Accurate and adjustable sand discharging device suitable for vacuum environment

Abstract

The invention discloses an accurate and adjustable sand production device suitable for a vacuum environment, and belongs to the technical field of sand erosion tests, the accurate and adjustable sand production device suitable for the vacuum environment comprises a cabin body, and a rotating arm and a plurality of sand distribution devices are arranged in the cabin body; each sand distribution device comprises a fixed base, a screw barrel is fixedly connected to the fixed base through a flange plate, the screw barrel is horizontally arranged, a material conveying screw is arranged in the screw barrel, the middle of the screw barrel is connected with a material storage hopper through a feeding pipe, and a driving source used for driving the material conveying screw to rotate is arranged at one end of the screw barrel; the driving source is connected with the fixed base, the other end of the screw barrel is a discharge port, and a plurality of layers of screens are arranged below the discharge port; in the precise and adjustable sand outlet device suitable for the vacuum environment, the sand distribution device is combined with a screw transmission mechanism and a multi-layer screen structure and is matched with the rotating arm to complete the aero-engine blade sand corrosion test, and an innovative aero-engine sand corrosion test solution is provided; and the accuracy, the efficiency, the reliability, the environment simulation authenticity and the like are remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of sand erosion test, and in particular relates to a precise and adjustable sand discharge device suitable for a vacuum environment. Background Art

[0002] Aircraft engines are often exposed to harsh environmental conditions, especially high concentrations of sand and dust that are common in deserts and arid areas. Inhalation of solid sand can seriously damage engine components, especially turbine and compressor blades, leading to reduced engine performance, shortened service life, increased maintenance costs, and may cause engine failure, threatening flight safety. In sand erosion experiments, the biggest challenge is the precise control of the sand delivery speed and amount to simulate different environmental conditions and evaluate material properties.

[0003] In the prior art, for the sand distribution device, a method is usually adopted in which the sand required for the test is directly placed in the storage funnel. An adjustable opening is set at the bottom of the funnel, and an electric push rod that can be slightly moved up and down is connected. The size of the opening is controlled by adjusting the electric push rod up and down, so as to achieve precise control of the amount of sand output. A sand guide tube and a multi-layer screen are also provided at the bottom of the funnel to disperse the sand and realize the sand area layout in the experiment. This method has obvious shortcomings:

[0004] First, the sand is very easy to get clogged at the sand outlet driven by the electric push rod, which affects the continuous progress of the test and may lead to large dispersion and poor regularity of the test results. In addition, there is no device such as a stirrer or vibrator at the sand outlet to evacuate the sand. Even if these devices are set up, it is difficult to accurately control the repeatability of the sand output.

[0005] Second, this method is difficult to achieve multi-level precise control of dust concentration. According to the GJB150-12A standard, the dust concentration in nature can be roughly divided into three situations: 1. For equipment that may work near helicopters flying over unpaved roads, the dust concentration is 2.2g / m3±0.5g / m3; 2. For equipment that will not be used or exposed near flying aircraft, but may work or be stored near moving ground vehicles without protection, the dust concentration is 1.1g / m3±0.3g / m3; 3. For equipment that is only exposed to natural conditions, the dust concentration is 0.18g / m3. For the third low-concentration situation, it is particularly difficult to control the free fall of sand particles by the size of the opening alone, which can easily lead to problems with large dispersion.

[0006] In the prior art, there is another technology that uses a screw thread to push sand particles and combines it with an auxiliary airflow to transport it into the main channel, where the sand particles are fully mixed with high-pressure gas in a relatively low airflow velocity environment, and then a specific pressurizing device is used to accelerate the gas-solid two-phase flow, thereby achieving supersonic acceleration of the sand particles. For example, -CN201710173864.7-An invention patent for a precise sand delivery device and sand delivery method. The shortcomings of this device and method are:

[0007] First, this method cannot simulate the sand erosion process of engine blades under real conditions, that is, the blades are in high-speed rotation during the sand swallowing process, and this method only simulates the ultra-high speed when the sand particles collide with the blades, which makes it difficult to realize the real process of sand erosion of the engine blades.

[0008] Second, this method cannot effectively control the uniformity and dispersion of sand particles, and it is difficult to simulate the sand and dust environment that varies from low density to high density in real situations. Since this method uses high-pressure gas to accelerate sand particles, the sandblasting area is relatively concentrated and the uniformity of sand particles is difficult to control, which is quite different from the real sand and dust environment. It is also difficult to simulate certain extreme environments under specific geographical conditions, affecting the accuracy and reliability of the experimental results.

[0009] Therefore, a new technical solution is urgently needed to solve the above problems in order to improve the continuity, regularity and accuracy of the test and ensure the effectiveness and reliability of the sand and dust test. Summary of the invention

[0010] In view of the deficiencies in the above-mentioned background technology, the present invention aims to provide a precise and adjustable sand discharging device suitable for a vacuum environment, which solves the problem of insufficient sand distributing accuracy in the existing sand distributing devices.

[0011] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is as follows:

[0012] Provided is a precise and adjustable sand discharging device suitable for a vacuum environment, comprising a cabin, wherein a rotating arm and a plurality of sand distributing devices are arranged inside the cabin; the plurality of sand distributing devices are arranged in a ring shape with the rotating axis of the rotating arm as the center;

[0013] Each sand-distributing device includes a fixed base, a screw barrel is fixedly connected to the fixed base via a flange, the screw barrel is horizontally arranged and a feeding screw is arranged inside the screw barrel, the middle part of the screw barrel is connected to a storage funnel via a feed pipe, one end of the screw barrel is provided with a driving source for driving the feeding screw to rotate, the driving source is connected to the fixed base, the other end of the screw barrel is a discharge port, a multi-layer screen is arranged below the discharge port, and the multi-layer screen is located at the top of the rotating arm.

[0014] The basic principle of the precise and adjustable sand discharging device suitable for a vacuum environment in the present invention is as follows: a rotating arm simulates the real state of an engine blade being impacted by sand particles when rotating; a plurality of sand spreading devices are used to spread sand evenly to simulate a real sand and dust environment, and the process is as follows: sand particles for sand erosion test are stored in a storage funnel, the sand particles enter the screw barrel through a feed pipe and are located between the threads of a feeding screw, a driving source drives the screw barrel feeding screw to rotate, and the sand particles between the threads are transported to a discharge port, and during the rotation of the screw, the sand particles flowing in from the feed port are stably delivered, and the sand particles freely fall to the multi-layer screen below the discharge port, and the multi-layer screen disperses the sand particles to form a columnar sand falling area, simulating a real sand and dust environment, and solving the problem of insufficient sand spreading accuracy in existing sand spreading devices.

[0015] Furthermore, the cabin is a sealed cabin, and the cabin is connected to an exhaust valve, which is used to communicate with a vacuum pumping device. The vacuum pumping device is started to extract the air in the cabin environment to simulate a vacuum environment, so that the sand erosion test can be completed in different environments.

[0016] Furthermore, the cabin is also provided with a plurality of lighting devices, which provide a stable light source for the environment in the cabin, so as to observe the sand distribution condition of the sand distribution device and the sand erosion test result of the rotating arm during the sand erosion test.

[0017] Furthermore, as a specific setting mode of the driving source, the driving source includes a stepper motor arranged on the fixed base, the stepper motor is arranged horizontally, the output shaft of the stepper motor is connected to an input screw through a coupling, and the free end of the input screw is fixedly connected to the end of the feeding screw. The stepper motor is provided with a motor controller for electrical connection with the upper machine, so as to remotely control the speed, working state and forward and reverse rotation of the stepper motor, so as to achieve the purpose of controlling the flow rate and distribution density of sand particles. The coupling connects the stepper motor and the input screw to transmit power, and absorbs and adjusts the axial deviation caused by assembly errors.

[0018] Furthermore, the multi-layer screen is fixedly connected to the end of the screw barrel via a connecting ear.

[0019] Furthermore, as a specific setting method for fixing the sand-distributing device in the cabin, a plurality of columns are fixedly arranged inside the cabin, and a sand-distributing device is fixed on each of the columns; the fixed base in each sand-distributing device is provided with an installation square opening that cooperates with the column and is fixed, and an installation locking hole is provided on the side wall of the installation square opening.

[0020] Furthermore, the mesh number of the multi-layer screen is 10 meshes, so as to ensure that the sand particles are evenly distributed in a columnar shape when passing through, thereby simulating a real sand and dust environment.

[0021] The present invention also provides a sand erosion test method of a precise and adjustable sand discharge device suitable for a vacuum environment, which comprises:

[0022] Step 1: Install and fix multiple sand distribution devices in the cabin;

[0023] Step 2, calibrate the sand output rate of the sand distribution device: prepare the required sand according to the specific test requirements, and the amount of sand should match the preset test time and sand distribution requirements; set a fixed speed for the driving source, and the driving source drives the feeding screw to rotate to transport sand. The sand output rate at the speed is calculated by timing and weighing. Change the speed of the driving source, repeat the above operation, and obtain the sand output rate at several different speeds. Fit the relationship curve according to the sand output rate data at these specific speeds to obtain the calibration relationship between the sand output rate and the driving source speed;

[0024] Step 3: The vacuum equipment evacuates the cabin through the vacuum valve to simulate a vacuum environment;

[0025] Step 4: The driving source is started according to the set parameters, gradually accelerated to the preset speed, and the sand particles are evenly pushed to the discharge port. The sand particles enter the multi-layer screen through the discharge port, and the multi-layer screen further disperses to simulate the real sand and dust environment;

[0026] Step 5, start the rotation of the rotating arm, which simulates the real state of the engine blades being impacted by sand particles during rotation. The sand spreading device and the rotating arm will stop after running for the preset sand erosion test time, clean the sand spreading device and the rotating arm, record the parameters set during the test, the running time and the test results, and complete the sand erosion test.

[0027] The beneficial effects of the present invention are:

[0028] 1. The invention discloses a precise and adjustable sand discharging device suitable for a vacuum environment. The sand distributing device combines a screw drive mechanism with a multi-layer screen structure and cooperates with a rotating arm to complete the sand erosion test of aircraft engine blades, providing an innovative solution for aircraft engine sand erosion test, which achieves significant improvements in accuracy, efficiency, reliability and environmental simulation authenticity.

[0029] 2. The core advantage of the screw drive mechanism of the present invention, which is a precise and adjustable sand discharge device suitable for a vacuum environment, lies in its precise and adjustable characteristics. Traditional sand erosion test equipment mostly relies on gravity or simple mechanical push, and it is difficult to accurately control the conveying speed and quantity of sand particles, resulting in inconsistency and poor repeatability in the test results. The screw drive mechanism pushes the sand particles through precise spiral threads, which can achieve precise control of the conveying speed and amount of sand particles. The requirements of different test conditions can be met by simply adjusting the speed of the feed screw. The feed screw allows continuous adjustment, so that the sand conveying process can be adjusted in real time according to the test requirements to cope with various variables that may arise during the test, thereby significantly improving the flexibility and scope of application of the test and meeting the needs of complex or changing test environments.

[0030] 3. The invention provides a precise and adjustable sand discharge device suitable for vacuum environment, which enhances the efficiency and continuity of the test. In traditional sand erosion tests, the problem of sand blockage often leads to test interruption, which requires manual cleaning or adjustment, affecting the continuity and overall efficiency of the test. The screw transmission mechanism of the invention effectively reduces the risk of sand blockage due to its unique structural design. The continuous rotation of the feeding screw and the driving action of the spiral thread ensure the uniform delivery of sand particles and avoid the aggregation and blockage of sand particles during the transmission process. The application of multi-layer screens further improves the continuity of the test. The hierarchical distribution and microporous structure of the multi-layer screens effectively disperse the sand particles, ensure that the sand particles fall evenly, and reduce local blockage caused by sand accumulation. At the same time, the screen design is easy to clean and maintain, which prolongs the stable operation time of the equipment and reduces the downtime caused by maintenance. In addition, the invention improves the reliability and repeatability of the test. Combined with the rotating arm type precise and adjustable sand discharge device suitable for vacuum environment, the high-speed rotating metal arm accurately simulates the real state of the engine blades being impacted by sand particles during rotation, which further enhances the credibility and comparability of the test data.

[0031] 4. The invention provides a precise and adjustable sand discharge device suitable for vacuum environment, which truly simulates complex environmental conditions. Aircraft engines face complex and changeable environments in actual operation, so it is crucial whether the test equipment can truly simulate such environmental conditions. The invention utilizes the dispersion function of precisely controllable screw drive and multi-layer screens to simulate sand and dust environments from low density to high density. It is not only suitable for conventional sand and dust concentrations, but also can simulate extreme sand and dust environments caused by climate change or specific geographical conditions, providing more comprehensive data support for engine design and testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The figure is a schematic diagram of the overall structure of a precise and adjustable sand discharge device suitable for a vacuum environment.

[0033] Figure 2 It is a schematic diagram of the overall structure of the sand distribution device.

[0034] Figure 3 This is a detailed display diagram of the discharge port.

[0035] Figure 4 It is a side cross-sectional view of the sand distribution device.

[0036] Figure 5 It is a schematic diagram of the structure of the feeding screw.

[0037] Among them, 1. Storage funnel; 2. Feed pipe; 3. Screw barrel; 4. Discharge port; 5. Flange; 6. Input screw; 7. Stepper motor; 8. Fixed base; 9. Connecting ear piece; 10. Multi-layer screen; 11. Feed screw; 12. Coupling; 13. Cabin; 14. Rotating arm; 15. Sand spreading device; 16. Lighting device; 17. Air extraction valve; 18. Column. DETAILED DESCRIPTION

[0038] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0039] like Figure 1 to Figure 5 As shown, the present solution provides a precise and adjustable sand discharging device suitable for a vacuum environment, which comprises a cabin 13, wherein a rotating arm 14 and a plurality of sand distributing devices 15 are arranged inside the cabin 13; the plurality of sand distributing devices 15 are arranged in a ring shape with the rotating axis of the rotating arm 14 as the center.

[0040] Each sand distribution device 15 includes a fixed base 8, a screw barrel 3 is fixedly connected to the fixed base 8 through a flange 5, the screw barrel 3 is horizontally arranged and a feeding screw 11 is arranged inside, the middle of the screw barrel 3 is connected to a storage funnel 1 through a feed pipe 2, one end of the screw barrel 3 is provided with a driving source for driving the feeding screw 11 to rotate, the driving source is connected to the fixed base 8, the other end of the screw barrel 3 is a discharge port 4, a multi-layer screen 10 is arranged below the discharge port 4, and the multi-layer screen 10 is located at the top of the rotating arm 14. Specifically, as Figure 3 As shown, the multi-layer screen 10 is fixedly connected to the end of the screw barrel 3 through the connecting ear piece 9. The mesh number of the multi-layer screen 10 is 10 meshes. It is ensured that the sand particles are evenly distributed in a columnar shape when passing through, thereby simulating a real sand and dust environment.

[0041] Preferably, a ceramic wear-resistant coating material is attached to the thread surface of the feeding screw 11 and the inner wall of the screw barrel 3 to further enhance the service life of the sand distribution device 15 .

[0042] As a specific arrangement mode for fixing the sand-distributing device 15 in the cabin 13, a plurality of columns 18 are fixedly arranged inside the cabin 13, and a sand-distributing device 15 is fixed on each of the columns 18; the fixed base 8 in each sand-distributing device 15 is provided with an installation square opening which cooperates with and is fixed to the column 18, and an installation locking hole is provided on the side wall of the installation square opening.

[0043] The basic principle of the precise and adjustable sand discharge device suitable for vacuum environment is: the rotating arm 14 simulates the real state of the engine blades being impacted by sand particles when rotating; multiple sand distribution devices 15 are used to evenly distribute sand to simulate the real sand and dust environment, and the process is: the storage funnel 1 stores sand particles for sand erosion test, and the sand particles enter the screw barrel 3 through the feed pipe 2 and are located between the threads of the feed screw 11. The driving source drives the screw barrel 3 and the feed screw 11 to rotate, and the sand particles between the threads are transported to the discharge port 4. During the rotation of the screw, the sand particles flowing into the feed port are stably delivered, and the sand particles fall freely to the multi-layer screen 10 below the discharge port 4. The multi-layer screen 10 disperses the sand particles to form a columnar sand falling area, simulating the real sand and dust environment, and solving the problem of insufficient sand distribution accuracy of the existing sand distribution device 15.

[0044] The sand distribution device 15 uses a screw drive mechanism to convey sand. The core advantage of the screw drive mechanism lies in its precise and adjustable characteristics. Traditional sand erosion test equipment mostly relies on gravity or simple mechanical push, and it is difficult to accurately control the conveying speed and amount of sand, resulting in inconsistency and poor repeatability in the test results. The screw drive mechanism pushes the sand through precise spiral threads, which can achieve precise control of the conveying speed and amount of sand. The requirements of different test conditions can be met by simply adjusting the speed of the feed screw 11. The feed screw 11 allows continuous adjustment, so that the sand conveying process can be adjusted in real time according to the test requirements to cope with various variables that may occur during the test, thereby significantly improving the flexibility and applicability of the test and meeting the needs of complex or changing test environments.

[0045] In traditional sand erosion tests, the problem of sand blockage often leads to test interruption, which requires manual cleaning or adjustment, affecting the continuity and overall efficiency of the test. The screw transmission mechanism of the present invention effectively reduces the risk of sand blockage due to its unique structural design. The continuous rotation of the feeding screw 11 and the driving effect of the spiral thread ensure the uniform transportation of sand particles and avoid sand aggregation and blockage during the transmission process. The application of the multi-layer screen 10 further improves the continuity of the test. The hierarchical distribution and microporous structure of the multi-layer screen 10 effectively disperse the sand particles, ensure that the sand particles fall evenly, and reduce local blockage caused by sand accumulation. At the same time, the screen design is easy to clean and maintain, which prolongs the stable operation time of the equipment and reduces the downtime caused by maintenance. In addition, the present invention improves the reliability and repeatability of the test. Combined with the rotating arm 14-type precise and adjustable sand discharge device suitable for vacuum environment, the high-speed rotating metal arm accurately simulates the real state of the engine blades being hit by sand particles during rotation, further enhancing the credibility and comparability of the test data.

[0046] Preferably, but not limited to, the cabin 13 is a sealed cabin, and the cabin 13 is connected to an air extraction valve 17, and the air extraction valve 17 is used to communicate with a vacuum extraction device, and the vacuum extraction device is started to extract the air in the cabin 13 environment to simulate a vacuum environment, so that the sand erosion test can be completed in different environments. The cabin 13 is also provided with a plurality of lighting devices 16, and the plurality of lighting devices 16 provide a stable light source for the environment in the cabin 13, so as to observe the sand distribution of the sand distribution device 15 and the sand erosion test results of the rotating arm 14 during the sand erosion test.

[0047] In this embodiment, as a specific setting mode of the driving source, the driving source includes a stepper motor 7 arranged on the fixed base 8, the stepper motor 7 is arranged horizontally, the output shaft of the stepper motor 7 is connected to the input screw 6 through the coupling 12, and the free end of the input screw 6 is fixedly connected to the end of the feeding screw 11. The stepper motor 7 is provided with a motor controller for electrical connection with the upper machine, so as to remotely control the speed, working state and forward and reverse rotation of the stepper motor 7, so as to achieve the purpose of controlling the flow rate and distribution density of the sand particles. The coupling 12 connects the stepper motor 7 and the input screw 6 to transmit power, and absorbs and adjusts the axial deviation caused by the assembly error.

[0048] The present invention also provides a sand erosion test method of a precise and adjustable sand discharge device suitable for a vacuum environment, which comprises:

[0049] Step 1. Install and fix multiple sand distribution devices 15 in the cabin 13; specifically, clean the contact surface between the fixed base 8 and the column 18 to ensure that there is no foreign matter to prevent tilting or loosening caused by impurities during the fixing process. Accurately align the installation square mouth of the fixed base 8 with the specified position of the column 18 to ensure that the fixed base 8 is accurately positioned, and then align the installation locking hole with the pre-set hole. Insert the top screw and rotate and tighten it through the preset thread, gradually tightening until the fixed base 8 is stable. At this time, it should be confirmed that there is no gap between the fixed base 8 and the column 18, and check by touch to ensure that there is no sign of shaking. The purpose of this step is to provide a stable support structure for subsequent test operations to ensure stability and accuracy during work.

[0050] Step 2, calibrate the sand output rate of the sand distribution device 15: prepare the required sand according to the specific test requirements, and the amount of sand should match the preset test time and sand distribution requirements to ensure the continuous and stable supply of sand during the test; to prevent the sand from accumulating and blocking the feed pipe 2, the operator should be careful to pour it and keep the sand in the funnel in a natural and flat state. The stepper motor 7 is set to a fixed speed, and the stepper motor 7 drives the feeding screw 11 to rotate to transport sand. The sand output rate at this speed is calculated by timing weighing measurement, and the speed of the stepper motor 7 is changed. Repeat the above operation to obtain the sand output rate at several different speeds. The relationship curve is fitted according to the sand output rate data at these specific speeds to obtain the calibration relationship between the sand output rate and the speed of the stepper motor 7; the purpose of this step is to ensure that the experimenter can set the corresponding motor speed according to the sand output rate required by the test.

[0051] Step 3: The vacuum equipment evacuates the cabin 13 through the vacuum valve 17 to simulate a vacuum environment;

[0052] Step 4, start spreading sand: the stepper motor 7 is started according to the set parameters, gradually accelerated to the preset speed, and the sand is evenly pushed to the discharge port 4. The sand enters the multi-layer screen 10 through the discharge port 4. The multi-layer screen 10 further disperses the sand to form a columnar sand falling area to simulate a real sand and dust environment. During the sand spreading process, by adjusting the speed of the stepper motor 7, the sand conveying process can be adjusted in real time according to the test requirements to cope with various variables that may occur during the test, thereby significantly improving the flexibility and applicability of the test and meeting the needs of complex or changeable test environments.

[0053] Step 5, start the rotating arm 14 to rotate, the rotating arm 14 simulates the real state of the engine blades being impacted by sand particles during rotation, the sand spreading device 15 and the rotating arm 14 stop after running to the preset sand erosion test time, clean the sand spreading device 15 and the rotating arm 14, record the parameters set during the test, the running time and the test results, and complete the sand erosion test.

[0054] In the above-mentioned sand erosion test method, the precisely controllable screw drive and the dispersion function of the multi-layer screen 10 can be used to simulate sand and dust environments from low density to high density. It is not only suitable for conventional sand and dust concentrations, but also can simulate extreme sand and dust environments caused by climate change or specific geographical conditions, providing more comprehensive data support for engine design and testing.

[0055] In summary, the present invention is a precise and adjustable sand discharging device suitable for a vacuum environment. The sand distributing device 15 combines the structure of a screw drive mechanism and a multi-layer screen 10, and cooperates with a rotating arm 14 to complete the sand erosion test of aircraft engine blades, providing an innovative aircraft engine sand erosion test solution, which achieves significant improvements in accuracy, efficiency, reliability and environmental simulation authenticity.

Claims

1. A precise and adjustable sand discharge device suitable for vacuum environment, characterized in that: It comprises a cabin, wherein a rotating arm and a plurality of sand spreading devices are arranged inside the cabin; the plurality of sand spreading devices are arranged in a ring direction with the rotating axis of the rotating arm as the center; Each sand-distributing device includes a fixed base, a screw barrel is fixedly connected to the fixed base via a flange, the screw barrel is horizontally arranged and a feeding screw is arranged inside the screw barrel, the middle part of the screw barrel is connected to a storage funnel via a feed pipe, one end of the screw barrel is provided with a driving source for driving the feeding screw to rotate, the driving source is connected to the fixed base, the other end of the screw barrel is a discharge port, a multi-layer screen is arranged below the discharge port, and the multi-layer screen is located at the top of the rotating arm.

2. The precise and adjustable sand discharge device suitable for vacuum environment according to claim 1, characterized in that: The cabin body is a sealed cabin, and is connected to an air extraction valve, which is used to communicate with a vacuum extraction device.

3. The precise and adjustable sand discharge device suitable for vacuum environment according to claim 1, characterized in that: The cabin is also provided with a plurality of lighting devices.

4. The precise and adjustable sand discharge device suitable for vacuum environment according to claim 1, characterized in that: The driving source comprises a stepper motor arranged on the fixed base, the stepper motor is arranged horizontally, the output shaft of the stepper motor is connected to an input screw through a coupling, and the free end of the input screw is fixedly connected to the end of the feeding screw.

5. The precise and adjustable sand discharge device suitable for vacuum environment according to claim 1, characterized in that: The multi-layer screen is fixedly connected to the end of the screw barrel through a connecting ear piece.

6. The precise and adjustable sand discharge device suitable for vacuum environment according to claim 1, characterized in that: A plurality of columns are fixedly arranged inside the cabin, and a sand spreading device is fixed on each of the columns; the fixed base in each sand spreading device is provided with an installation square opening fixed with the column, and the side wall of the installation square opening is provided with an installation locking hole.

7. The precise and adjustable sand discharge device suitable for vacuum environment according to claim 1, characterized in that: The mesh number of the multi-layer screen is 10 meshes.

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