Porous metal piston gas-driven powder supply device

Abstract

The porous metal piston gas-driven powder supply device comprises a high-pressure gas cylinder and a powder box barrel, the high-pressure gas cylinder penetrates through a powder box rear sealing head through a first pipeline to be led to a driving cavity, a pressure reducing valve and a first electromagnetic valve are sequentially arranged on the first pipeline, and a second pipeline is separated from the first pipeline after the pressure reducing valve; the second pipeline is located between the pressure reducing valve and the first electromagnetic valve, the second pipeline is led to the fluidizing gas inlet nozzle through the second electromagnetic valve and then led to the flowing cavity, the driving cavity is inflated to push powder to move forwards, the fluidizing cavity is inflated to fluidize the powder to achieve supply, the porous metal piston body has certain air permeability, the pressure of the two cavities can be balanced, and the inflation time is shortened. In the long-time working process, chamber pressure difference sharp increase caused by flow design mismatching is avoided, the stability of the powder supply process is improved, powder compaction is prevented, and the structure failure risk is reduced; in addition, the porous metal piston body introduces gas to fluidize the powder in the working process, the gas inlet area of fluidizing gas can be increased, the gas inlet position is more diversified, and therefore the fluidizing conveying capacity of the powder fuel is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of powder fuel engines and relates to a powder supply device, in particular to a porous metal piston air-driven powder supply device. Background Art

[0002] The constant pressure difference between the driving chamber and the fluidizing chamber in the gas-driven powder fuel supply system is the premise and basis for the stable advancement of the piston, and is the key to ensuring the stable powder supply and constant thrust of the powder ramjet engine. At present, the gas-driven powder fuel supply system generally adopts a piston structure that is impermeable to gas. In this way, the designed moving speed of the gas-driven piston must match the moving speed required by the supply flow to ensure that the pressure difference between the driving chamber and the fluidizing chamber remains balanced. If the designed moving speed of the piston is less than the moving speed required by the supply flow, the actual supply flow will deviate from the designed flow, causing the thrust of the powder engine to deviate. If the designed moving speed of the piston is greater than the actual speed under the supply flow, the pressure in the driving chamber will continue to rise, and the excessively high pressure difference between the driving chamber and the fluidizing chamber will compact the fuel, increase the difficulty of fluidized delivery, reduce the supply flow, and hinder the stable output of the engine thrust; in addition, with the continuous supply of powder fuel, the pressure in the driving chamber will continue to rise, and the risk of failure of the powder box structure will increase sharply, limiting the working time of the supply device. Therefore, how to solve the problems of insufficient powder flow supply and chamber pressure imbalance caused by the design deviation of piston movement speed is of great significance to promoting efficient fluidization of powder in the tank and realizing continuous and stable transportation of powder fuel by the powder supply system. Summary of the invention

[0003] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a porous metal piston air-driven powder supply device to solve the technical problem in the prior art that the chamber pressure imbalance under long-term powder supply conditions leads to unstable powder flow supply and increased risk of structural failure.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0005] A porous metal piston gas-driven powder supply device comprises a high-pressure gas cylinder and a powder box cylinder with two ends open, wherein the high-pressure gas cylinder is connected to one end of a first pipeline, a pressure reducing valve and a first solenoid valve are sequentially arranged on the first pipeline, a second pipeline is branched from the first pipeline after the pressure reducing valve, one end of the second pipeline is located between the pressure reducing valve and the first solenoid valve, and the other end of the second pipeline leads to a fluidizing gas inlet nozzle through the second solenoid valve.

[0006] A porous metal piston body is coaxially installed in the powder box cylinder, and a powder box rear head is coaxially installed on the powder box cylinder on the axial side of the porous metal piston body. The powder box rear head and the porous metal piston body form a driving chamber.

[0007] The other end of the first pipeline passes through the rear end of the powder box and leads to the driving chamber.

[0008] A conical air-permeable fluidizing hood is coaxially installed inside the powder box cylinder on the other axial side of the porous metal piston body. The outer surface of the fluidizing hood is sleeved with a powder box front head. The fluidizing hood and the porous metal piston body form a fluidizing chamber.

[0009] A mounting hole is provided on the front sealing head of the powder box, and the fluidizing gas inlet nozzle is installed in the mounting hole.

[0010] The fluidizing hood and the front cover of the powder box are provided with an axially penetrating powder discharge channel; the fluidizing chamber is connected with the third pipeline through the powder discharge channel.

[0011] The present invention also has the following technical features:

[0012] The porous metal piston body includes a first granular layer close to one side of the driving chamber, a second granular layer and a third granular layer are arranged in sequence next to the first granular layer, the outer diameter of the third granular layer is smaller than the first granular layer and the second granular layer, a piston Y-shaped sealing ring is sleeved on the third granular layer, and an open-hole pressure plate with pores evenly distributed on the surface of the third granular layer close to the fluidizing chamber is provided, and a sealing ring fastening bolt is provided on the open-hole pressure plate, and the sealing ring fastening bolt is connected to the porous metal piston body for pressing the open-hole pressure plate and the piston Y-shaped sealing ring, and the pores of the first granular layer, the second granular layer and the third granular layer become smaller step by step.

[0013] The thickness of the first granular layer is 1 / 20 to 1 / 5 of the outer diameter of the first granular layer; the thickness of the second granular layer is 1 / 20 to 1 / 5 of the outer diameter of the second granular layer; the thickness of the third granular layer is 1 / 20 to 1 / 5 of the outer diameter of the third granular layer.

[0014] The pore diameter of the pores of the third particle size layer close to the contact surface of the perforated pressing plate is smaller than the quartile diameter under the supplied powder.

[0015] The fluidizing hood is a porous structure, and the average diameter of the pores in the porous structure is smaller than the lower quartile diameter of the supplied powder.

[0016] The porous metal piston body can move in the powder box cylinder, the radial direction of the porous metal piston body is constrained by the powder box cylinder, and the outer contour of the porous metal piston body is cylindrical.

[0017] A piston O-type sealing ring is arranged between the porous metal piston body and the powder box cylinder body.

[0018] The powder box rear sealing head and the powder box cylinder are fixed by circumferentially evenly distributed fastening bolts, and the outer contour of the powder box rear sealing head is cylindrical.

[0019] Powder box O-type sealing rings are respectively arranged between the powder box rear sealing head, the powder box front sealing head and the powder box cylinder.

[0020] The third pipeline is provided with a ball valve.

[0021] A limiting convex ring is arranged inside the powder box cylinder on the other axial side of the porous metal piston body, and the fluidizing hood is placed on the limiting convex ring. A powder box front head pressure ring is detachably installed at the end of the powder box cylinder on the other axial side of the porous metal piston body, and the powder box front head pressure ring is pressed on the powder box front head.

[0022] The powder box front head pressure ring and the powder box cylinder are also fixed by circumferentially evenly distributed fastening bolts, and the outer contour of the powder box front head pressure ring is cylindrical.

[0023] Compared with the prior art, the present invention has the following technical effects:

[0024] (I) The porous metal piston body proposed in the present invention replaces the traditional solid piston. The porous metal piston body has the function of air permeability and powder isolation, allowing the gas to flow between the driving chamber and the fluidizing chamber through the gap channel in the piston. When the chamber is inflated, the pressure of the two chambers can be balanced more quickly, shortening the inflation time; during long-term working, the surge in chamber pressure difference caused by flow design mismatch is avoided, the stability of the powder supply process is improved, powder compaction is prevented, and the risk of structural failure is reduced.

[0025] (II) The porous metal piston body proposed in the present invention is ventilated to fluidize powder during operation, which can increase the fluidizing gas intake area and make the intake position more diverse, thereby improving the fluidization conveying capacity of powder fuel.

[0026] (III) The porous metal piston body proposed in the present invention adopts a multi-level pore diameter and porosity form. Compared with a single pore diameter and porosity, the front and rear pressure difference of the porous metal piston body, the length of the porous metal piston body, the weight of the porous metal piston body and the flow resistance of the porous metal piston body can be designed more freely.

[0027] (IV) The powder box cylinder of the present invention is connected to the front and rear heads of the powder box by circumferentially evenly distributed fastening bolts. The overall structure is relatively compact, ensuring the consistency of the outer contour diameter of the powder box cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the axial symmetric section principle of the porous metal piston powder supply device.

[0029] The meanings of the numbers in the figure are as follows: 1-high-pressure gas cylinder, 2-powder box cylinder, 3-first pipeline, 4-pressure reducing valve, 5-first solenoid valve, 6-second pipeline, 7-second solenoid valve, 8-fluidizing gas inlet nozzle, 9-porous metal piston body, 901-first particle size layer, 902-second particle size layer, 903-third particle size layer, 10-powder box rear head, 11-driving chamber, 12-fluidizing hood, 13-powder box front head, 14-fluidizing chamber, 15-mounting hole, 16-powder discharge channel, 17-third pipeline, 18-piston Y-type sealing ring, 19-opening pressure plate, 20-sealing ring fastening bolt, 21-piston O-type sealing ring, 22-fastening bolt, 23-powder box O-type sealing ring, 24-ball valve, 25-limiting convex ring, 26-powder box front head pressure ring.

[0030] The specific contents of the present invention are further described in detail below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0031] It should be noted that, unless otherwise specified, all components and devices in the present invention are components and devices known in the prior art.

[0032] In accordance with the above technical scheme, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical scheme of this application fall within the protection scope of the present invention.

[0033] Example:

[0034] This embodiment provides a porous metal piston gas driven powder supply device, which adopts a positive pressure powder supply structure design, including a high-pressure gas cylinder 1 and a powder box cylinder 2 with both ends open. Figure 1 As shown, the high-pressure gas cylinder 1 is connected to one end of the first pipeline 3, and a pressure reducing valve 4 and a first solenoid valve 5 are provided on the first pipeline 3 in sequence. A second pipeline 6 is branched from the first pipeline 3 after the pressure reducing valve 4, and one end of the second pipeline 6 is located between the pressure reducing valve 4 and the first solenoid valve 5, and the other end of the second pipeline 6 is connected to the fluidizing gas inlet nozzle 8 through the second solenoid valve 7.

[0035] like Figure 1 As shown, a porous metal piston body 9 is coaxially installed in the powder box cylinder 2, and a powder box rear head 10 is coaxially installed on the powder box cylinder 2 on the axial side of the porous metal piston body 9. The powder box rear head 10 and the porous metal piston body 9 form a driving chamber 11.

[0036] like Figure 1 As shown, the other end of the first pipeline 3 passes through the powder box rear head 10 and leads to the driving chamber 11.

[0037] like Figure 1As shown, a conical air-permeable fluidizing hood 12 is coaxially installed inside the powder box cylinder 2 on the other axial side of the porous metal piston body 9, and a powder box front head 13 is sleeved on the outer surface of the fluidizing hood 12. The fluidizing hood 12 and the porous metal piston body 9 form a fluidizing chamber 14.

[0038] like Figure 1 As shown, a mounting hole 15 is provided on the front sealing head 13 of the powder box, and the fluidizing gas inlet nozzle 8 is installed in the mounting hole 15 .

[0039] like Figure 1 As shown, the fluidizing hood 12 and the powder box front head 13 are provided with an axially penetrating powder discharge channel 16 ; the fluidizing chamber 14 is connected to the third pipeline 17 through the powder discharge channel 16 .

[0040] like Figure 1 As shown, the porous metal piston body 9 includes a first granular layer 901 close to the driving chamber 11, and a second granular layer 902 and a third granular layer 903 are sequentially arranged next to the first granular layer 901. The outer diameter of the third granular layer 903 is smaller than that of the first granular layer 901 and the second granular layer 902. A piston Y-type sealing ring 18 is sleeved on the third granular layer 903. A perforated pressure plate 19 with pores evenly distributed on the surface of the third granular layer 903 close to the fluidizing chamber 14 is provided. The perforated pressure plate 19 is provided with 3 to 5 sealing ring fastening bolts 20. The sealing ring fastening bolts 20 are connected to the porous metal piston body 9 and are used for pressing the perforated pressure plate 19 and the piston Y-type sealing ring 18. The pores of the first granular layer 901, the second granular layer 902 and the third granular layer 903 become smaller step by step.

[0041] Specifically in this embodiment, the first granularity layer 901, the second granularity layer 902 and the third granularity layer 903 in the porous metal piston body 9 are sintered by several metal powder particles of different particle sizes. By designing the multi-level porosity and pore diameter, the pressure difference of the porous metal piston body 9 and the ventilation flow rate of the porous metal piston body 9 can be adjusted; the porous metal piston body 9 has axial air permeability, and the fluidizing gas fluidizes the powder from the front and rear directions of the porous metal piston body 9 and the fluidizing hood 12 respectively; the sintered powder used for the granular layer is generally set to 2 to 4 layers.

[0042] Specifically in this embodiment, the thickness of the first granular layer 901 is 1 / 20 to 1 / 5 of the outer diameter of the first granular layer 901; the thickness of the second granular layer 902 is 1 / 20 to 1 / 5 of the outer diameter of the second granular layer 902; the thickness of the third granular layer 903 is 1 / 20 to 1 / 5 of the outer diameter of the third granular layer 903, ensuring that the porous metal piston body 9 will not flip over inside the powder cylinder 2.

[0043] Specifically in this embodiment, the pore diameter of the pores 903 of the third particle size layer close to the contact surface of the perforated pressure plate 19 is smaller than the quartile diameter under the supplied powder.

[0044] Specifically in this embodiment, the third granular layer 903 is sleeved with a piston Y-shaped sealing ring 18, which is made of hard rubber. When compressed, its edge stretches outward to prevent powder from leaking at the edge when moving.

[0045] Specifically in this embodiment, the porous metal piston body 9 can move in the powder box cylinder 2, the radial direction of the porous metal piston body 9 is constrained by the powder box cylinder 2, and the outer contour of the porous metal piston body 9 is cylindrical;

[0046] Specifically in this embodiment, a piston O-ring 21 is provided between the porous metal piston body 9 and the powder box cylinder 2 , and the piston O-ring 21 is used to prevent gas from passing through the gap between the porous metal piston body 9 and the powder box cylinder 2 .

[0047] Specifically in this embodiment, the powder box rear head 10 is fixed to the powder box cylinder 2 by using circumferentially evenly distributed fastening bolts 22, and the outer contour of the powder box rear head 4 is cylindrical.

[0048] Specifically in this embodiment, powder box O-type sealing rings 23 are respectively provided between the powder box rear head 10 and the powder box front head 13 and the powder box cylinder 2 , and the powder box O-type sealing rings 23 are used to ensure the air tightness of the powder box cylinder 2 structure.

[0049] Specifically in this embodiment, a ball valve 24 is provided on the third pipeline 17 .

[0050] Specifically in this embodiment, the high-pressure gas cylinder 1 is connected to the driving chamber 11 and the fluidizing chamber 14 respectively through the first pipeline 3 and the second pipeline 6, the high-pressure gas cylinder 1 provides a gas source for inflating the powder box cylinder 2, the high-pressure gas cylinder 1 provides power for the porous metal piston body 9 to push the powder, and the high-pressure gas cylinder 1 provides a carrier gas for the fluidization of the powder fuel.

[0051] Specifically in this embodiment, the pressure reducing valve 4 is used to adjust the gas circuit output pressure, the first solenoid valve 5 and the second solenoid valve 7 are used to control the switches of the first pipeline 3 and the second pipeline 6, and the ball valve 24 is used to control the switch of the third pipeline 17. The pressure reducing valve 4 is adjusted, and the first solenoid valve 5, the second solenoid valve 7 and the ball valve 24 are controlled to realize the inflation and powder supply functions of the powder box cylinder 2.

[0052] Specifically in this embodiment, a limiting convex ring 25 is provided inside the powder box cylinder 2 on the other axial side of the porous metal piston body 9, and the fluidizing hood 12 is pressed on the limiting convex ring 25. A powder box front head pressure ring 26 is detachably installed on the end of the powder box cylinder 2 on the other axial side of the porous metal piston body 9, and the powder box front head pressure ring 26 is pressed on the powder box front head 13.

[0053] Specifically, in this embodiment, the fluidizing hood 12 is a porous structure with air permeability, and the average diameter of the pores of the porous structure is smaller than the lower quartile diameter of the supplied powder. The fluidizing hood 12 can prevent the powder from penetrating and effectively prevent the powder from flowing back upstream from the fluidizing gas inlet nozzle 8.

[0054] Specifically in this embodiment, the powder box front head pressure ring 26 and the powder box cylinder 2 are also fixed by circumferentially evenly distributed fastening bolts 22, and the outer contour of the powder box front head pressure ring 26 is cylindrical.

[0055] Specifically in this embodiment, the powder supply device can be divided into two stages according to the working process: an air filling stage and a powder supply stage.

[0056] Inflation stage: adjust the pressure reducing valve 4 to the inflation pressure, and the gas in the high-pressure gas cylinder 1 will pass through the fluidizing gas inlet nozzle 8 on the powder box rear head 10 and the powder box front head 13 on the first pipeline 3 and the second pipeline 6, and then enter the drive chamber 11 and the fluidizing chamber 14 for inflation. Since the porous metal piston body 9 has gas permeability, the gas in the two chambers can exchange and flow during the inflation process, promoting the pressure balance of the chamber. On the one hand, this reduces the unnecessary displacement of the porous metal piston body 9 caused by the pressure difference, and avoids the porous metal piston body 9 moving forward to compact the powder or moving backward to increase the cavity in the fluidizing chamber 14; on the other hand, it greatly shortens the time required for the inflation process, and achieves a rapid response to the inflation process.

[0057] Working stage: adjust the pressure reducing valve 4 to the working pressure. The gas in the high-pressure gas cylinder 1 is divided into the first pipeline 3 and the second pipeline 6 after passing through the pressure reducing valve 4. The first pipeline 3 enters the driving chamber 11 through the powder box rear head 4, pressurizes the driving chamber 11, and the piston moves forward under the action of the pressure difference, squeezing the powder fuel to flow to the outlet. At the same time, the gas will also pass through the porous metal piston body 9 as a carrier gas to assist the fluidization of the powder from the third particle size layer 903 side; the second pipeline 6 enters the fluidization chamber 14 through the fluidization gas inlet nozzle 8 on the powder box front head 13, disperses the airflow through the fluidization hood 12, and enters the fluidization chamber 14 to realize the fluidization of the head powder. The porous metal piston body 9 makes the fluidization air intake more diversified, and multiple airflows participate in fluidization, which can improve the uniformity of the gas-solid two-phase flow and make the powder supply flow more stable. Finally, the gas-solid two-phase flow is rectified through the powder discharge channel 16 set on the powder box front head 13, and is directly transported out of the powder fuel supply device through the third pipeline 17.

[0058] It has been verified that the fluidization efficiency in the powder box cylinder 2 of this solution is significantly improved. Even if there is a deviation in the design of the gas flow rate of the two chambers, the two chambers can be quickly balanced through the porous metal piston body 9, and the front and rear pressure difference can be adaptively adjusted, which solves the problem of excessive front and rear pressure difference of the porous metal piston body 9 during long-term operation, which compacts the powder fuel and affects the stable supply of the flow rate.

[0059] In the powder supply system using a traditional solid piston body, the gas entering the drive chamber 11 from the first pipeline 3 only pushes the piston to move and no longer participates in the fluidization of the powder in the fluidizing chamber. The gas entering from the second pipeline 6 through the fluidizing gas inlet nozzle 8 is dispersed through the fluidizing hood 12, and then the powder fuel in the fluidizing chamber 14 is fluidized, rectified through the powder discharge channel 16 set on the front head 13 of the powder box, and directly transported out of the powder fuel supply device through the third pipeline 17. During the inflation stage, due to the different volumes of the driving chamber 11 and the fluidizing chamber 14 and the flow resistance throttling effect of their connecting pipelines, there will be a difference in the time it takes for the driving chamber 11 and the fluidizing chamber 14 to reach the specified pressure. During the inflation process, there will be a pressure difference before and after the porous metal piston body 9. When the pressure rise of the driving chamber 11 is faster than that of the fluidizing chamber 14, the porous metal piston body 9 will move toward the fluidizing chamber 14 to compact the powder, making it difficult to start the powder supply process; when the pressure rise of the fluidizing chamber 14 is faster than that of the driving chamber 11, the porous metal piston body 9 will move toward the driving chamber 11, the cavity in the fluidizing chamber 14 will become larger, and the startup characteristics will seriously deviate from the design, resulting in a huge deviation in the initial supply flow rate. During the working stage, when the designed inflation speed is greater than the estimated powder supply speed, the pressure of the driving chamber 11 gradually increases with the powder supply, and a pressure difference will be formed between the driving chamber 11 and the fluidizing chamber 14. The pressure difference pushes the porous metal piston body 9 to compact the powder, reducing the powder supply flow rate and reducing the stability of the flow supply. When the pressure difference increases to the point where the static friction generated by the powder is greater than the drag force of the airflow on the particles, the powder is blocked and can no longer be supplied normally. It has been verified that under this scheme, the powder fuel is easily compacted and agglomerated during the supply process, reducing the stability and reliability of the system powder flow supply.

Claims

1. A porous metal piston gas-driven powder supply device, comprising a high-pressure gas cylinder (1) and a powder box cylinder (2) with both ends open, characterized in that: The high-pressure gas cylinder (1) is connected to one end of a first pipeline (3), a pressure reducing valve (4) and a first solenoid valve (5) are provided on the first pipeline (3) in sequence, a second pipeline (6) is branched from the first pipeline (3) after the pressure reducing valve (4), one end of the second pipeline (6) is located between the pressure reducing valve (4) and the first solenoid valve (5), and the other end of the second pipeline (6) is connected to a fluidizing gas inlet nozzle (8) through a second solenoid valve (7); A porous metal piston body (9) is coaxially installed in the powder box cylinder (2), a powder box rear head (10) is coaxially installed on the powder box cylinder (2) on one axial side of the porous metal piston body (9), and the powder box rear head (10) and the porous metal piston body (9) form a driving chamber (11); The other end of the first pipeline (3) passes through the rear end cover (10) of the powder box and leads to the driving chamber (11); A conical air-permeable fluidizing hood (12) is coaxially mounted inside the powder box cylinder (2) on the other axial side of the porous metal piston body (9), a powder box front head (13) is sleeved on the outer surface of the fluidizing hood (12), and the fluidizing hood (12) and the porous metal piston body (9) form a fluidizing chamber (14); The powder box front cover (13) is provided with a mounting hole (15), and the fluidizing gas inlet nozzle (8) is installed in the mounting hole (15); The fluidizing hood (12) and the powder box front head (13) are provided with an axially penetrating powder discharge channel (16); the fluidizing chamber (14) is connected to the third pipeline (17) through the powder discharge channel (16).

2. The porous metal piston gas-driven powder supply device according to claim 1, characterized in that: The porous metal piston body (9) comprises a first granular layer (901) close to a driving chamber (11), a second granular layer (902) and a third granular layer (903) are arranged in sequence next to the first granular layer (901), the outer diameter of the third granular layer (903) is smaller than the first granular layer (901) and the second granular layer (902), a piston Y-shaped sealing ring (18) is sleeved on the third granular layer (903), a perforated pressure plate (19) with pores evenly distributed on the surface of the third granular layer (903) close to the fluidizing chamber (14), the perforated pressure plate (19) is provided with a sealing ring fastening bolt (20), and the pores of the first granular layer (901), the second granular layer (902) and the third granular layer (903) become smaller step by step.

3. The porous metal piston gas-driven powder supply device according to claim 2, characterized in that: The thickness of the first granular layer (901) is 1 / 20 to 1 / 5 of the outer diameter of the first granular layer (901); the thickness of the second granular layer (902) is 1 / 20 to 1 / 5 of the outer diameter of the second granular layer (902); and the thickness of the third granular layer (903) is 1 / 20 to 1 / 5 of the outer diameter of the third granular layer (903).

4. The porous metal piston gas-driven powder supply device according to claim 3, characterized in that: The pores (903) of the third particle size layer have a pore diameter close to the contact surface of the perforated platen (19) that is smaller than the quartile diameter of the supplied powder; The fluidizing hood (12) is a porous structure, and the average diameter of the pores in the porous structure is smaller than the lower quartile diameter of the supplied powder.

5. The porous metal piston gas-driven powder supply device according to claim 1, characterized in that: The porous metal piston body (9) is movable in the powder box cylinder (2), the radial direction of the porous metal piston body (9) is constrained by the powder box cylinder (2), and the outer contour of the porous metal piston body (9) is cylindrical; A piston O-type sealing ring (21) is provided between the porous metal piston body (9) and the powder box cylinder body (2).

6. The porous metal piston gas-driven powder supply device according to claim 1, characterized in that: The powder box rear sealing head (10) and the powder box barrel (2) are fixed by means of circumferentially evenly distributed fastening bolts (22), and the outer contour of the powder box rear sealing head (4) is cylindrical.

7. The porous metal piston gas-driven powder supply device according to claim 1, characterized in that: Powder box O-type sealing rings (23) are respectively arranged between the powder box rear sealing head (10) and the powder box front sealing head (13) and the powder box cylinder (2).

8. The porous metal piston gas-driven powder supply device according to claim 1, characterized in that: The third pipeline (17) is provided with a ball valve (24).

9. The porous metal piston gas-driven powder supply device according to claim 1, characterized in that: A limiting convex ring (25) is arranged inside the powder box cylinder (2) on the other axial side of the porous metal piston body (9), and the fluidizing hood (12) is pressed on the limiting convex ring (25). A powder box front head pressure ring (26) is detachably installed at the end of the powder box cylinder (2) on the other axial side of the porous metal piston body (9), and the powder box front head pressure ring (26) is pressed on the powder box front head (13).

10. The porous metal piston gas-driven powder supply device according to claim 9, characterized in that: The powder box front head pressure ring (26) and the powder box barrel (2) are also fixed by circumferentially evenly distributed fastening bolts (22), and the outer contour of the powder box front head pressure ring (26) is cylindrical.

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