Sand supply mechanism of an erosion test system

Abstract

The application provides a sand feeding mechanism of an erosion test system, which comprises a material tank, a horizontal screw feeding mechanism arranged at the outlet of the material tank, a vertical sand feeding pipe arranged below the outlet of the screw feeding mechanism, a first star-shaped material valve arranged at the top end of the sand feeding pipe, and a top edge of a valve flap of the first star-shaped material valve capable of rotating to the outlet of the screw feeding mechanism, sand particles introduced from the material tank by the screw feeding mechanism are distributed between adjacent valve flaps of the first star-shaped material valve when entering the outlet. An air channel is arranged on the screw shaft of the screw feeding mechanism, all outlets of the air channel are located directly above the outlet, all outlets of the air channel jointly form a ring structure, and the air channel inlet is circumscribed by a compressed air source. The low-cost feeding mechanism with simple structure can control the trace sand feeding amount in the erosion test process within a small range, and can ensure that the feeding mechanism is not blocked.

Description

Technical Field

[0001] This invention relates to erosion testing equipment, and more specifically to a sand supply mechanism for an erosion testing system. Background Technology

[0002] An airflow erosion testing device / system is a device used to evaluate the wear resistance and abrasion resistance of materials. Its main functions include at least: injecting erosion particles into the main airflow by accelerating the airflow to generate a high-speed airflow; controlling the airflow pressure to ensure airflow stability and to enable the particles to reach a high velocity of 200 m / s; and using erosion particles such as sand and gravel carried by the airflow to conduct erosion tests on samples, simulating wear conditions in actual use. In existing technologies, typical erosion testing equipment in China includes: For example, the rotary vacuum erosion resistance testing machine developed by China Mining and Metallurgical Technology Group Co., Ltd., which includes a sand collection device, a sand throwing device, and a vacuum chamber. At least one test piece is installed inside the vacuum chamber. The outlet of the sand collection device is connected to the inlet of the sand throwing device. The sand throwing device is rotatably positioned inside the vacuum chamber and is used to receive the sand discharged from the sand collection device and throw the sand towards each test piece under centrifugal force. Another example is the erosion resistance testing device for sieve tubes disclosed in document CN103852412B, which includes a sand tank, a mixing output unit, a sand mixer with a cavity, an acceleration tube, a nozzle, and a testing unit. The bottom of the sand tank has a sand outlet, which is connected to the cavity of the sand mixer. The mixing output unit includes parallel gas and liquid pipelines. The mixing output unit is connected in series with the sand mixer, acceleration tube, and nozzle, with the nozzle aligned with the testing unit. Although the aforementioned erosion resistance testing device uses a screw feeder to feed sand particles, it cannot accurately control the amount of sand particles fed.

[0003] In the fields of aerospace and other high-end equipment, the main purpose of airflow erosion testing equipment is to study abrasive wear testing methods under medium and high temperature conditions, especially in high-temperature environments such as turbofan engines, to evaluate the wear resistance of materials and coatings. This requires precise control of the feed rate of a small amount of sand during the testing process. Although some countries, such as Germany and the United States, have been able to control the feed rate of trace sand particles to within 5 g / min during the testing process, their sand supply devices are very complex and the equipment costs are extremely high. Domestic research in this area is still relatively weak, making it necessary to implement domestic substitution. More importantly, many technical difficulties were encountered during the research and development process, one of which was how to control the precise and smooth feeding of trace amounts (not exceeding 5 g / min) of sand particles without clogging the feeding mechanism. Summary of the Invention

[0004] This invention provides a sand feeding mechanism for an erosion test system, which is used to accurately control the amount of micro-sized sand particles fed during airflow erosion tests.

[0005] The present invention adopts the following technical solution.

[0006] A sand supply mechanism for an erosion test system includes a tank, a horizontally arranged screw feeder at the outlet of the tank, a vertically arranged sand supply pipe below the discharge port of the screw feeder, the discharge port having a diameter of no more than 4 mm, and a first star-shaped valve at the top of the sand supply pipe. The top edge of the valve disc of the first star-shaped valve can rotate to the discharge port of the screw feeder. When sand particles introduced from the tank by the screw feeder enter the discharge port, they are distributed between adjacent valve discs of the first star-shaped valve.

[0007] In order to control the precise and smooth feeding of micro-sized sand particles without clogging the feeding mechanism, an air passage is provided on the screw shaft of the screw feeder. All outlets of the air passage are located directly above the discharge hole, and all outlets of the air passage together form a ring structure. The air passage inlet is connected to an external compressed air source.

[0008] As a preferred option, all outlet orifices of the airway are larger than the diameter of the sand particles.

[0009] As a preferred embodiment, all outlets of the air passage are located within the threaded grooves of the screw shaft.

[0010] In this invention, the first star-shaped valve includes a valve body, and a valve disc assembly is provided inside the valve body. All valve discs of the valve disc assembly are evenly arranged on a rotating shaft, and the outer edges of all valve discs are fitted with the inner wall of the valve body. The rotating shaft of the valve disc assembly is connected to a servo motor.

[0011] In order to control the feeding of micro-sized sand particles more accurately and smoothly without clogging the feeding mechanism, a second star-shaped material valve is installed on the sand supply pipe and below the first star-shaped material valve. The second star-shaped material valve is driven by a servo motor.

[0012] Beneficial effects: The present invention uses a simple and low-cost feeding mechanism to control the feeding amount of trace sand particles (particle size not greater than 150 mesh) during the erosion test process within the range of 1.8~5g / min, while ensuring that the feeding mechanism does not get clogged and that the sand particles can be smoothly discharged from the small discharge hole. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the sand supply mechanism of the erosion test system in Example 1; Figure 2 This is a schematic diagram of the screw shaft of the sand supply mechanism in the embodiment; Figure 3 This is a schematic cross-sectional view of the first star-shaped material valve of the sand supply mechanism in the embodiment; Figure 4 This is a schematic diagram of the internal structure of the first star-shaped material valve of the sand supply mechanism in the embodiment; Figure 5This is a schematic diagram of the sand supply mechanism of the erosion test system in Example 2; Figure 6 A schematic diagram of the sand supply mechanism of the erosion test system in Comparative Example 1; Figure 7 This is a schematic diagram of the sand supply mechanism of the erosion test system in Comparative Example 1. Detailed Implementation

[0014] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] Example 1 Combination Figures 1 to 4 As shown, a sand supply mechanism for an erosion test system includes a tank 1. A horizontally arranged screw feeder is provided at the outlet of the tank 1. A vertically arranged sand supply pipe 2 is provided below the discharge hole 4 of the screw feeder. The diameter of the discharge hole is 4 mm. A first star-shaped material valve 3 is provided at the top of the sand supply pipe 2. The top edge of the valve disc of the first star-shaped material valve 3 can rotate to the discharge hole 4 of the screw feeder. When the sand particles introduced from the tank 1 by the screw feeder enter the discharge hole 4, they are distributed between the adjacent valve discs of the first star-shaped material valve 3.

[0016] In this embodiment, an air passage 6 is provided on the screw shaft 5 of the screw feeding mechanism. All outlets of the air passage 6 are located directly above the discharge hole 4, and all outlets of the air passage 6 together form a ring structure. The inlet of the air passage 6 is connected to an external compressed air source. The diameter of all outlet holes of the air passage 6 is larger than the diameter of the sand particles, and all outlets of the air passage 6 are located in the threaded grooves of the screw shaft 5. During use, the high-pressure gas ejected through all outlets of the air passage 6 applies force to the sand particles that are spun and squeezed, which helps to prevent the sand particles from sticking / aggregating in the threaded grooves and prevents the first star-shaped material valve 3 from being blocked. On the other hand, it can also promote the sand particles to enter between the adjacent valve discs of the star-shaped material valve.

[0017] In this embodiment, the first star-shaped material valve 3 includes a valve body 31, within which a valve disc assembly 32 is disposed. All valve discs of the valve disc assembly 32 are evenly arranged on a rotating shaft, and the outer edges of all valve discs are clearance-fitted to the inner wall of the valve body 31. The rotating shaft of the valve disc assembly 32 is connected to a servo motor 33, and the included angle between adjacent valve discs of the first star-shaped material valve 3 is 60°. A second star-shaped material valve 7 is disposed on the sand supply pipe 2 and located below the first star-shaped material valve 3. The second star-shaped material valve 7 is driven by a servo motor 2, and the included angle between adjacent valve discs of the second star-shaped material valve 7 is 30°.

[0018] In use, test sand (particle size ≤ 150 mesh) is loaded into hopper 1, and then the cover of hopper 1 is closed. The servo motors of the first star-shaped valve 3 and the second star-shaped valve 7 are then turned on, activating the screw feeding mechanism. Simultaneously, the compressed air source connected to the inlet of air passage 6 is turned on. Subsequently, the sand particles move forward along the screw shaft 5 under the action of the screw feeding mechanism. When the sand particles enter the threaded groove at the discharge hole 4, some of them are squeezed by the screw shaft 5 and enter the discharge hole 4, falling between the adjacent valve discs of the first star-shaped valve 3. The high-pressure gas pumped in by the compressed air source further promotes the sand particles to enter between the adjacent valve discs of the first star-shaped valve 3 below the discharge hole 4. Subsequently, the sand particles entering the discharge hole 4 are introduced in batches into the cavity between the two star-shaped valves by the first star-shaped valve 3 until the sand particles are blown between the adjacent valve discs of the second star-shaped valve 7. Then, the sand particles in the cavity are drawn out in batches by the high-speed rotation of the second star-shaped valve 7, so that the feed rate of the trace sand particles can be controlled within the range of 1.8~3g / min (after the sand feeding process is stable, five random one-minute measurements are taken, and the measurement results are 2.3g / min, 1.8g / min, 3g / min, 2.5g / min, and 1.8g / min in sequence), while ensuring that the feeding mechanism is not blocked.

[0019] Example 2 Combination Figures 2 to 5 As shown, a sand supply mechanism for an erosion test system includes a tank 1. A horizontally arranged screw feeder is provided at the outlet of the tank 1. A vertically arranged sand supply pipe 2 is provided below the discharge hole 4 of the screw feeder. A first star-shaped material valve 3 is provided at the top of the sand supply pipe 2. The top edge of the valve disc of the first star-shaped material valve 3 can rotate to the discharge hole 4 of the screw feeder. The diameter of the discharge hole is 3.5 mm. When the sand particles introduced from the tank 1 by the screw feeder enter the discharge hole 4, they are distributed between the adjacent valve discs of the first star-shaped material valve 3.

[0020] In this embodiment, an air passage 6 is provided on the screw shaft 5 of the screw feeding mechanism. All outlets of the air passage 6 are located directly above the discharge hole 4, and all outlets of the air passage 6 together form a ring structure. The inlet of the air passage 6 is connected to an external compressed air source. The diameter of all outlet holes of the air passage 6 is larger than the diameter of the sand particles, and all outlets of the air passage 6 are located in the threaded grooves of the screw shaft 5. During use, the high-pressure gas ejected through all outlets of the air passage 6 applies force to the sand particles that are spun and squeezed, preventing the sand particles from sticking / aggregating in the threaded grooves and preventing the first star-shaped material valve 3 from being blocked. On the other hand, it can promote the sand particles to enter between the adjacent valve discs of the star-shaped material valve. In this embodiment, the first star-shaped material valve 3 includes a valve body 31, and a valve disc assembly 32 is provided inside the valve body 31. All valve discs of the valve disc assembly 32 are evenly arranged on the rotating shaft. The outer edge clearance of all valve discs fits the inner wall of the valve body 31. The rotating shaft of the valve disc assembly 32 is connected to a servo motor 33. The included angle between adjacent valve discs of the first star-shaped material valve 3 is 60°.

[0021] In use, test sand (particle size ≤ 150 mesh) is loaded into hopper 1, then the cover of hopper 1 is closed. The servo motor of the first star-shaped material valve 3 is then turned on, activating the screw feeding mechanism. Simultaneously, the compressed air source connected to the inlet of air passage 6 is turned on. Subsequently, the sand particles move forward along the screw shaft 5 under the action of the screw feeding mechanism. When the sand particles enter the threaded groove at the discharge hole 4, some of the sand particles, under the screw extrusion action of the screw shaft 5, enter the discharge hole 4 and fall between the adjacent valve discs of the first star-shaped material valve 3. The high-pressure compressed air pumped in by the compressed air source... The compressed gas further forces the sand particles into the space between the adjacent valve discs of the first star-shaped material valve 3 below the discharge hole 4. Then, with the help of the high-speed rotation of the first star-shaped material valve 3, the sand particles in the tube are drawn out in batches, thereby controlling the amount of micro-sized sand particles fed within the range of 4~5g / min (after the sand feeding process stabilizes, five random one-minute measurements are taken, and the measurement results are 4.3g / min, 4g / min, 4.4g / min, 5g / min, and 4.7g / min in sequence), and ensuring that the feeding mechanism is not blocked.

[0022] Comparative Example 1 A sand supply mechanism for an erosion testing system, such as Figure 6As shown, the system includes a material tank 1, with a horizontally arranged screw feeder mechanism at the outlet of the material tank 1. Below the discharge port 4 of the screw feeder mechanism, a vertically arranged sand supply pipe 2 is located. A first star-shaped material valve 3 is located at the top of the sand supply pipe 2. The top edge of the valve disc of the first star-shaped material valve 3 can rotate to the discharge port 4 of the screw feeder mechanism. The diameter of the discharge port is 4mm. When sand particles introduced from the material tank 1 by the screw feeder mechanism enter the discharge port 4, they are distributed between adjacent valve discs of the first star-shaped material valve 3. The first star-shaped material valve 3 includes a valve body 31, within which a valve disc assembly 32 is installed. All valve discs of the valve disc assembly 32 are evenly arranged on a rotating shaft, with the outer edges of all valve discs fitting against the inner wall of the valve body 31. The rotating shaft of the valve disc assembly 32 is connected to a servo motor 33. The included angle between adjacent valve discs of the first star-shaped material valve 3 is 60°. During use, the first star-shaped material valve 3 is prone to clogging. This solution demonstrates that the problem of fine sand particles clogging the material cannot be solved simply by using the star-shaped valve 3 located at the discharge port 4.

[0023] Comparative Example 2 A sand supply mechanism for an erosion testing system, such as Figure 7 As shown, the system includes a material tank 1, with a horizontally arranged screw feeding mechanism at the outlet of the material tank 1. A vertically arranged sand supply pipe 2 is located below the discharge hole 4 of the screw feeding mechanism. A first star-shaped material valve 3 is located at the top of the sand supply pipe 2. The top edge of the valve disc of the first star-shaped material valve 3 can rotate to the discharge hole 4 of the screw feeding mechanism. The diameter of the discharge hole is 3.5 mm. When sand particles introduced from the material tank 1 by the screw feeding mechanism enter the discharge hole 4, they are distributed between adjacent valve discs of the first star-shaped material valve 3. The first star-shaped material valve 3 includes a valve body 31, within which a valve disc assembly 32 is installed. All valve discs of the valve disc assembly 32 are evenly arranged on a rotating shaft, with the outer edges of all valve discs fitting against the inner wall of the valve body 31. The rotating shaft of the valve disc assembly 32 is connected to a servo motor 33, and the included angle between adjacent valve discs of the first star-shaped material valve 3 is 60°. The material tank 1 is equipped with an air source port 8 connected to a compressed air source. During use, compressed gas is directly introduced into the material tank 1 through the compressed air source, but the problem of easy clogging still exists at the first star-shaped material valve 3. This solution proves that pressurizing the material tank 1 cannot solve the problem of fine sand particles clogging the material.

[0024] Comparative Example 3 A sand supply mechanism for an erosion testing system includes a material tank 1. A horizontally arranged screw feeder is installed at the outlet of the material tank 1. A vertically arranged sand supply pipe 2 is installed below the discharge hole 4 of the screw feeder. The discharge hole 4 has a diameter of 4 mm. Sand particles introduced from the material tank 1 by the screw feeder fall into the sand supply pipe 2 when they enter the discharge hole 4. During use, the discharge hole 4 is prone to clogging and intermittent discharge is likely to occur.

[0025] One of the key points of this invention is the air passage 6 located directly above the discharge hole 4 and its external compressed air source. If the air passage 6 is too far from the discharge hole 4 or located on the sand supply pipe 2, it will not be able to prevent fine sand particles of a specific size from sticking / aggregating in the threaded groove and prevent the inlet of the first star-shaped material valve 3 (specific aperture, aperture not greater than 4mm) from being blocked.

Claims

1. A sand supply mechanism for an erosion test system, comprising a material tank (1), a horizontally arranged screw feeding mechanism being provided at the outlet of the material tank (1), and a vertically arranged sand supply pipe (2) being provided below the discharge hole (4) of the screw feeding mechanism, characterized in that: A first star-shaped material valve (3) is provided at the top of the sand supply pipe (2). The top edge of the valve disc of the first star-shaped material valve (3) can rotate to the discharge hole (4) of the screw feeding mechanism. When the sand particles introduced from the material tank (1) by the screw feeding mechanism enter the discharge hole (4), they are distributed between the adjacent valve discs of the first star-shaped material valve (3). An air passage (6) is provided on the screw shaft (5) of the screw feeding mechanism. All the outlets of the air passage (6) are located directly above the discharge hole (4), and all the outlets of the air passage (6) together form a ring structure. The inlet of the air passage (6) is connected to an external compressed air source. All outlets of the air passage (6) are located in the threaded groove of the screw shaft (5); the sand feeding mechanism is used for feeding micro-sized sand particles with a particle size not greater than 150 mesh; the diameter of the discharge hole (4) is not greater than 4 mm.

2. The sand supply mechanism of the erosion test system according to claim 1, characterized in that: All outlet orifices of the air passage (6) are larger than the diameter of the sand particles.

3. The sand supply mechanism of the erosion test system according to any one of claims 1-2, characterized in that: The first star-shaped material valve (3) includes a valve body (31), and a valve disc assembly (32) is provided inside the valve body (31). All valve discs of the valve disc assembly (32) are evenly arranged on the rotating shaft. The outer edge clearance of all valve discs is matched with the inner wall of the valve body (31). The rotating shaft of the valve disc assembly (32) is connected to a servo motor (33).

4. The sand supply mechanism of the erosion test system according to claim 3, characterized in that: A second star-shaped material valve (7) is provided on the sand supply pipe (2) and below the first star-shaped material valve (3). The second star-shaped material valve (7) is driven by a servo motor.

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