Self-control assisted blowing valve of positive pressure dense phase pneumatic conveying pipeline

Abstract

The utility model discloses a kind of self-control blow assisting valves of positive pressure dense phase pneumatic conveying pipeline, including the air inlet, gas outlet and exhaust port respectively set in the both sides and rear center position of valve seat, and air inlet, gas outlet and exhaust port are communicated arrangement, the inside of valve seat is equipped with first blow assisting valve assembly, to utilize first blow assisting valve assembly to realize the communication or plugging of gas outlet and air inlet, and the communication or plugging of gas outlet and exhaust port, the both sides of valve cover are close to middle position and are respectively set with connecting air hole A and connecting air hole B, and connecting air hole A and connecting air hole B are interconnected, the inside of valve cover is equipped with second blow assisting valve assembly, to utilize second blow assisting valve assembly to realize the communication or plugging of connecting air hole A and connecting air hole B. The utility model does not need to rely on PLC control, reduces control point, reduces equipment cost, and simultaneously avoids the equipment shutdown problem caused by PLC control related component failure.

Description

Technical Field

[0001] This utility model relates to the field of pipeline gas supply application technology, and in particular to a self-controlled purging valve for a positive pressure dense phase pneumatic conveying pipeline. Background Technology

[0002] Positive pressure dense phase pneumatic conveying utilizes compressed air to propel granular materials in the form of plugs or moving beds under conditions of high pressure, low gas velocity, and high solid-to-gas ratio. Dense phase can significantly reduce pulverization and wear, and has better energy consumption. However, it has inherent problems such as large pressure loss along the pipeline and plug growth. As the conveying distance increases, the number of bends and vertical pipes increases, the material friction coefficient is high, or the water content fluctuates, the local flow velocity may approach or fall below the critical residence velocity. The front end of the plug thickens, friction increases sharply, and eventually "dead plugs" and pipe blockage occur. To solve the above problems, "blowing valves" are arranged along the pipeline in engineering to inject compressed gas in small doses in a distributed manner or to form local pressurization zones.

[0003] Existing pneumatic conveying valves, which use PLC control to open along the pipeline, have many drawbacks: blindly replenishing air leads to increased compressed air consumption, increasing the load on terminal equipment; increasing the number of PLC control points raises costs; multiple pneumatic conveying devices along the pipeline result in a high failure rate and difficult maintenance; and because the pressure cannot be adjusted, pipe blockage is prone to occur when the material's moisture content, particle shape, or temperature changes, making it unable to adapt to changes in material characteristics. Therefore, this utility model proposes a self-controlled pneumatic conveying valve for positive pressure dense phase pneumatic conveying pipelines. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a self-controlled blowing valve for a positive pressure dense phase pneumatic conveying pipeline, so as to solve the problems of high compressed air consumption, reliance on PLC control, high failure rate and inability to adapt to changes in material characteristics of existing blowing valves.

[0005] To solve the above-mentioned technical problems, the present invention adopts a technical solution as follows: a self-controlled blow valve for a positive pressure dense phase pneumatic conveying pipeline is provided, including a valve seat and a valve cover. The valve cover is installed on the top of the valve seat by bolts set at its corners, and a sealing ring is provided at the connection between the valve cover and the valve seat to ensure the sealing of the connection between the two. The valve seat has an air inlet, an air outlet, and an exhaust port on both sides and at the center of the rear, and the air inlet, air outlet, and exhaust port are connected. The valve seat is equipped with a first blowing valve assembly, which is used to connect or block the air outlet and the air inlet, as well as connect or block the air outlet and the exhaust port. The valve cover has connecting air holes A and B on both sides near the middle, and connecting air holes A and B are interconnected. Connecting air hole A is connected to the top of the first blowing valve assembly through the channel between the inner cavity of the valve cover and the first blowing valve assembly. A second blowing valve assembly is installed inside the valve cover to realize the connection or blockage of connecting air hole A and connecting air hole B.

[0006] The present invention is further configured such that: the first blowing valve assembly includes a valve stem A located inside the valve seat, a spring A is sleeved on the bottom of the valve stem A, a lower valve core is sleeved on the outer wall of the valve stem A near the bottom, and the lower valve core is wrapped around the spring A, a lower end cover is slidably connected to the outer wall of the lower valve core, and the lower end cover is sealed to the bottom center of the valve seat, and the two ends of the spring A respectively abut against the opposite surfaces of the lower end cover and the lower valve core, driving the valve stem A to move the lower valve core, thereby realizing the connection and sealing of the air outlet and the air inlet.

[0007] With the above technical solution, spring A is always in a pre-tightened state. When valve stem A is subjected to an upward force, it will drive the lower valve core to move upward. At this time, the channel between the air outlet and the air inlet is opened, and compressed air can enter from the air inlet and be injected into the delivery pipeline through the air outlet. When the upward force on valve stem A disappears, the elastic restoring force of spring A will push the lower valve core to move downward, blocking the channel between the air outlet and the air inlet, stopping the air replenishment operation, and realizing the automatic switching between the connection and blockage of the air outlet and the air inlet.

[0008] The present invention is further configured such that: an upper valve core is sleeved on the outer wall of the valve stem A near the middle position, and a spring B is wrapped around the upper valve core on the outer wall of the valve stem A; an upper end cover is slidably connected to the outer wall of the upper valve core, and the upper end cover is fixed inside the valve seat by a retaining ring; the two ends of the spring B respectively abut against the opposite surfaces of the upper end cover and the upper valve core; the top of the valve stem A penetrates the upper end cover, and a piston A is locked to the end face of the valve stem A by a nut, driving the valve stem A to move the upper valve core, thereby realizing the connection and sealing of the air outlet and the exhaust port.

[0009] Through the above technical solution, spring B provides elastic support force. Under normal conditions, the upper valve core remains in a blocked state between the outlet and exhaust port under the action of spring B. When piston A is subjected to downward pressure, it will push valve rod A to move downward, thereby driving the upper valve core to compress spring B and move downward. At this time, the channel between the outlet and exhaust port is opened, and the high-pressure gas in the pipeline can be discharged through the exhaust port to achieve pressure release. When the pressure on piston A disappears, the elastic restoring force of spring B pushes the upper valve core to reset, re-blocking the channel, and completing the automatic switching between exhaust and blocking.

[0010] The present invention is further configured such that: the top of the valve seat is provided with an adapter groove adapted to piston A at piston A, and a through groove connected to the air outlet is provided at the bottom of the adapter groove.

[0011] Through the above technical solution, the adapter groove provides a stable installation and movement space for piston A, ensuring that piston A can move up and down smoothly; the through groove connected to the air outlet allows the gas pressure in the air outlet to be transmitted to the bottom of piston A. When the pressure in the air outlet reaches the set threshold, the gas pressure will push piston A to move upward, thereby triggering the subsequent valve core action, realizing automatic control based on the pressure in the pipeline.

[0012] The present invention is further configured such that: the second blowing valve assembly includes a valve stem B installed inside the valve cover, an air guide hole is provided at the middle position of the valve stem B, a plurality of sealing valve cores are fixedly connected to the outer wall of the valve stem B on one side of the air guide hole, a spring C is installed at one end of the valve stem B, a piston B is sleeved on the valve stem B near the other end, and a sealing cover is installed at the other end of the valve stem B, and the sealing cover is fixed to one side edge of the valve cover by a retaining ring.

[0013] Through the above technical solution, spring C provides elastic restoring force to valve stem B, allowing piston B to move within the movable groove in the valve cover. When an external trigger signal causes piston B to be subjected to force, it pushes valve stem B to compress spring C and move, causing the sealing valve core to change position, thereby achieving connection between connecting air port A and connecting air port B through the air guide hole. When the trigger signal disappears, the elastic restoring force of spring C pushes valve stem B to reset, and the sealing valve core re-seals the channel, realizing the on / off control of connecting air port A and connecting air port B, thus playing a pilot control role.

[0014] The present invention is further configured such that: a matching through groove is provided inside the valve cover at the sealing valve core located near the middle position, and when the sealing valve core is located in the through groove, the connection between the connecting air hole A and the connecting air hole B can be realized through the air guide hole; a sealing ring is sleeved on the outer wall of the sealing valve core, and the sealing ring can fit against the inner wall of the valve cover adjacent to the through groove.

[0015] Through the above technical solution, the mating structure of the sealing valve core and the through groove ensures smooth gas flow when connecting air hole A and connecting air hole B are connected; the sealing ring on the outer wall of the sealing valve core enhances the sealing performance, and when the sealing valve core is reset and blocked, it can effectively prevent gas leakage, ensure the sealing between connecting air hole A and connecting air hole B in the non-connected state, and ensure the accuracy of pilot control.

[0016] The present invention is further configured such that: a matching movable groove is provided inside the valve cover at the piston B, and the outer wall of the piston B is smoothly attached to the inner wall of the movable groove, while a vent hole communicating with the outside is provided on the side wall of the movable groove.

[0017] Through the above technical solution, the smooth and fitted structural design reduces the friction force when piston B moves in the movable groove, ensuring smooth piston B movement and improving the response speed of pilot control; the vent holes on the side wall of the movable groove allow the air pressure on both sides of piston B to be balanced with the outside, avoiding the piston B movement being obstructed due to air pressure difference, and ensuring the stable operation of the second blow valve assembly.

[0018] The beneficial effects of this utility model are as follows: 1. The self-controlled blow valve for a positive pressure dense phase pneumatic conveying pipeline proposed in this utility model does not rely on PLC control, which reduces the number of control points, lowers equipment costs, and avoids equipment downtime caused by PLC control component failures. 2. The self-controlled air supply valve for a positive pressure dense phase pneumatic conveying pipeline proposed in this utility model can automatically adjust the air supply volume and pressure according to the pressure changes in the conveying pipeline by means of the synergistic action of the first air supply valve assembly and the second air supply valve assembly, so as to achieve precise air supply, reduce the waste of compressed air, and reduce the load on the terminal equipment. 3. The self-controlled blowing valve for a positive pressure dense phase pneumatic conveying pipeline proposed in this utility model has a simple overall structure, which reduces the complex arrangement of multiple blowing points along the line, lowers the equipment failure rate, and facilitates inspection and maintenance. 4. The self-controlled blowing valve of the positive pressure dense phase pneumatic conveying pipeline proposed in this utility model can adapt to changes in the material's moisture content, particle shape, temperature, and other characteristics, and avoid pipe blockage through automatic pressure regulation, thereby improving the stability and adaptability of the positive pressure dense phase pneumatic conveying system. Attached Figure Description

[0019] Figure 1 This is the first structural diagram of the present invention; Figure 2 This is the second structural diagram of the present invention; Figure 3 This is a cross-sectional view of the present invention; Figure 4 This utility model provides a diagram illustrating the overflow state of the connection between the outlet and the exhaust port when the outlet pressure is high. Figure 5 This utility model provides a diagram showing the connection and air supply status between the air outlet and the air inlet when the air outlet pressure is low. Figure 6 This utility model is a state diagram of pressure equilibrium; Figure 7 This is a diagram showing the connection state of connecting vent A and connecting vent B when the pressure is balanced according to this utility model. Figure 8 This is a structural diagram of the first blowing valve assembly in this utility model; Figure 9This is a structural diagram of the second blowing valve assembly in this utility model.

[0020] In the diagram: 1. Valve seat; 11. Air inlet; 12. Air outlet; 13. Exhaust outlet; 2. Valve cover; 21. Connecting air port A; 22. Connecting air port B; 3. First auxiliary blowing valve assembly; 31. Valve stem A; 32. Spring A; 33. Lower valve core; 34. Lower end cover; 35. Upper valve core; 36. Spring B; 37. Upper end cover; 38. Snap ring; 39. Piston A; 4. Second auxiliary blowing valve assembly; 41. Valve stem B; 42. Air guide hole; 43. Sealing valve core; 44. Spring C; 45. Piston B; 46. Sealing cover; 47. Snap ring. Detailed Implementation

[0021] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the scope of protection of the present invention.

[0022] like Figures 1-3 As shown, a self-controlled blow valve for a positive pressure dense phase pneumatic conveying pipeline includes a valve seat 1 and a valve cover 2. The valve cover 2 is installed on the top of the valve seat 1 by bolts set at its corners, and a sealing ring is provided at the connection between the valve cover 2 and the valve seat 1 to ensure the sealing of the connection between the two. The valve seat 1 has an air inlet 11, an air outlet 12, and an exhaust outlet 13 respectively on both sides and at the center of the rear. The air inlet 11, the air outlet 12, and the exhaust outlet 13 are connected. The valve seat 1 is equipped with a first blowing valve assembly 3, which is used to connect or block the air outlet 12 with the air inlet 11, and to connect or block the air outlet 12 with the exhaust outlet 13.

[0023] like Figures 4-6 and Figure 8As shown, the first blow-assisted valve assembly 3 includes a valve stem A31 located inside the valve seat 1. A spring A32 is sleeved on the bottom of the valve stem A31. A lower valve core 33 is sleeved on the outer wall of the valve stem A31 near the bottom, and the lower valve core 33 is wrapped around the spring A32. A lower end cap 34 is slidably connected to the outer wall of the lower valve core 33, and the lower end cap 34 is sealed to the bottom center of the valve seat 1. The two ends of the spring A32 abut against the opposite surfaces of the lower end cap 34 and the lower valve core 33, respectively, driving the valve stem A31 to move the lower valve core 33, thereby realizing the communication between the air outlet 12 and the air inlet 11. When the valve stem A31 is subjected to an upward force, it will drive the lower valve core 33 to move upward. At this time, the channel between the air outlet 12 and the air inlet 11 is opened, and compressed air can enter from the air inlet 11 and be injected into the delivery pipeline through the air outlet 12. When the upward force on the valve stem A31 disappears, the elastic restoring force of the spring A32 will push the lower valve core 33 to move downward, blocking the channel between the air outlet 12 and the air inlet 11, stopping the air replenishment operation, and realizing the automatic switching between the connection and blockage of the air outlet 12 and the air inlet 11. An upper valve core 35 is sleeved on the outer wall of valve stem A31 near its center. A spring B36 is wrapped around the upper valve core 35 on the outer wall of valve stem A31. An upper end cover 37 is slidably connected to the outer wall of the upper valve core 35 and is fixed to the inside of valve seat 1 by a retaining ring 38. The two ends of spring B36 abut against the opposite surfaces of the upper end cover 37 and the upper valve core 35, respectively. The top of valve stem A31 passes through the upper end cover 37, and a piston A39 is locked to the end face of valve stem A31 by a nut. The piston A39 drives valve stem A31 to move the upper valve core 35, thereby connecting and blocking the air outlet 12 and the exhaust port 13. B36 provides elastic support. Under normal conditions, the upper valve core 35 remains blocked from the passage between the outlet 12 and the exhaust port 13 under the action of the spring B36. When the piston A39 is subjected to downward pressure, it will push the valve stem A31 to move downward, which will in turn drive the upper valve core 35 to compress the spring B36 and move downward. At this time, the passage between the outlet 12 and the exhaust port 13 is opened, and the high-pressure gas in the pipeline can be discharged through the exhaust port 13 to achieve pressure release. When the pressure on the piston A39 is removed, the elastic restoring force of the spring B36 pushes the upper valve core 35 to reset, re-blocking the passage, and completing the automatic switching between exhaust and blocking. The top of the valve seat 1 has an adapter groove that matches the piston A39, and a through groove that connects to the air outlet 12 is opened at the bottom of the adapter groove. At the same time, a channel that connects to the inner cavity of the valve cover 2 is opened on the side wall of the adapter groove to force the second blow-assisted valve 4 to be driven. The adapter groove provides a stable installation and movement space for the piston A39, ensuring that the piston A39 can move up and down smoothly. The through groove that connects to the air outlet 12 allows the gas pressure in the air outlet 12 to be transmitted to the bottom of the piston A39. When the pressure in the air outlet 12 reaches a set threshold, the gas pressure will push the piston A39 to move upward, thereby triggering the subsequent valve core action, realizing automatic control based on the pressure in the pipeline.

[0024] like Figure 3 , Figure 7 and Figure 9 As shown, the valve cover 2 has connecting air holes A21 and B22 on both sides near the middle, and the connecting air holes A21 and B22 are interconnected. The connecting air hole A21 is connected to the top of the first blowing valve assembly 3 through the channel between the inner cavity of the valve cover 2 and the first blowing valve assembly 3. The valve cover 2 is equipped with a second blowing valve assembly 4, so as to realize the connection or blockage of the connecting air hole A21 and the connecting air hole B22. The second blow-assisted valve assembly 4 includes a valve stem B41 installed inside the valve cover 2. An air guide hole 42 is provided in the middle of the valve stem B41. Multiple sealing valve cores 43 are fixedly connected to the outer wall of the valve stem B41 on one side of the air guide hole 42. A spring C44 is installed at one end of the valve stem B41, and a piston B45 is sleeved on the valve stem B41 near the other end. A sealing cap 46 is installed at the other end of the valve stem B41, and the sealing cap 46 is fixed to one edge of the valve cover 2 by a retaining ring 47. The spring C44 provides an elastic restoring force to the valve stem B41. The piston B45 can move within the movable groove in the valve cover 2. When an external trigger signal causes the piston B45 to be subjected to force, it will push the valve stem B41 to compress the spring C44 and move, thereby causing the sealing valve core 43 to change position, and then realize the connection between the connecting air port A21 and the connecting air port B22 through the air guide port 42. When the trigger signal disappears, the elastic restoring force of the spring C44 pushes the valve stem B41 to reset, and the sealing valve core 43 re-seals the channel, realizing the on / off control of the connecting air port A21 and the connecting air port B22, playing the role of pilot control. The valve cover 2 has a matching through groove at the sealing valve core 43 located near the center. When the sealing valve core 43 is in the through groove, the connection between the connecting air hole A21 and the connecting air hole B22 can be achieved through the air guide hole 42. The outer wall of the sealing valve core 43 is fitted with a sealing ring, which can fit against the inner wall of the valve cover 2 adjacent to the through groove. The mating structure of the sealing valve core 43 and the through groove ensures smooth gas flow when the connecting air hole A21 and the connecting air hole B22 are connected. The sealing ring on the outer wall of the sealing valve core 43 enhances the sealing performance. When the sealing valve core 43 is reset and sealed, it can effectively prevent gas leakage and ensure the sealing between the connecting air hole A21 and the connecting air hole B22 in the non-connected state, thus ensuring the accuracy of pilot control. The valve cover 2 has a matching movable groove inside the piston B45, and the outer wall of the piston B45 is smoothly fitted to the inner wall of the movable groove. At the same time, the side wall of the movable groove has a vent hole that communicates with the outside. The smooth fit design reduces the friction of the piston B45 when it moves in the movable groove, ensuring smooth movement of the piston B45 and improving the response speed of the pilot control. The vent hole on the side wall of the movable groove allows the air pressure on both sides of the piston B45 to be balanced with the outside, avoiding the piston B45 from being obstructed due to air pressure difference, and ensuring the stable operation of the second blow valve assembly 4.

[0025] In use, the outlet 12 of this device is sealed to the positive pressure dense phase pneumatic conveying pipeline, the inlet 11 is connected to a compressed air source with rated pressure, and the connecting ports A21 and B22 are connected to a preset control air circuit and regulated gas is introduced. At this time, the regulated gas conveyed by the connecting port A21 is introduced into the adapter groove of the piston A39 through the inner cavity channel of the valve cover 2. Under the action of gas pressure, the piston A39 is pushed downward, which in turn drives the valve stem A31 to move downward synchronously, so that the lower valve core 33 opens the communication channel between the inlet 11 and the outlet 12. Compressed air is precisely injected into the conveying pipeline through the outlet 12 to complete the gas replenishment start-up. Overpressure relief control: During continuous gas supply, when the gas pressure at outlet 12 rises to a preset threshold, high-pressure gas enters the adapter slot through the connecting channel between the adapter slot and outlet 12, generating an upward thrust on piston A39, causing piston A39 to move valve stem A31 upward. During this process, lower valve core 33 reverses its action to block the connecting pipeline between inlet 11 and outlet 12, while upper valve core 35 opens the pressure relief channel between outlet 12 and exhaust port 13. Overpressure gas in the pipeline is discharged in an orderly manner through exhaust port 13, achieving dynamic unloading of system pressure. Pressure balance and stability control: Part of the high-pressure gas in the adapter slot is introduced into the inner cavity of the valve cover 2 through the side wall channel, which drives the piston B45 in the second blow-assisted valve assembly 4. This pushes the piston B45 to move the valve stem B41 laterally, and discharges the compressed gas through the channel connecting the exhaust port 13. This causes the position of the air guide hole 42 on the valve stem B41 to shift, thereby realizing the connection between the connecting air hole A21 and the connecting air hole B22. The regulating gas in the connecting air hole A21 enters the adapter slot of the piston A39 through the connecting channel, forming a dynamic balance comparison with the real-time pressure of the outlet 12. When the gas pressure at the outlet 12 and the connecting port B22 reaches equilibrium, the piston A39 remains stationary. The upper valve core 35 and the lower valve core 33 reliably seal the channels between the outlet 12 and the exhaust port 13, and between the outlet 12 and the inlet port 11, respectively, maintaining a stable pressure in the system. The gas discharged from the connecting port B22 enters the connecting port A21 of the next self-controlled blow-up valve. When the gas pressure at the outlet 12 decreases, the second blow-up valve assembly 4 resets using the compressed spring C44 and discharges the gas in the inner cavity of the valve cover 2 through the exhaust port 13 connected to the connecting channel, closing the next self-controlled blow-up valve.

[0026] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A self-controlled blow-up valve for a positive pressure dense phase pneumatic conveying pipeline, comprising a valve seat (1) and a valve cover (2), characterized in that: The valve cover (2) is installed on the top of the valve seat (1) by bolts set at its corners, and a sealing ring is provided at the connection between the valve cover (2) and the valve seat (1) to ensure the sealing of the connection between the two. The valve seat (1) has an air inlet (11), an air outlet (12) and an exhaust outlet (13) respectively on both sides and at the center of the rear. The air inlet (11), the air outlet (12) and the exhaust outlet (13) are connected. The valve seat (1) is equipped with a first blowing valve assembly (3) to achieve the connection or blockage between the air outlet (12) and the air inlet (11), and the connection or blockage between the air outlet (12) and the exhaust outlet (13). The valve cover (2) has connecting air holes A (21) and B (22) on both sides near the middle, and the connecting air holes A (21) and B (22) are connected to each other. The connecting air hole A (21) is connected to the top of the first blowing valve assembly (3) through the channel between the inner cavity of the valve cover (2) and the first blowing valve assembly (3). The valve cover (2) is equipped with a second blowing valve assembly (4) so ​​as to realize the connection or blockage of the connecting air hole A (21) and the connecting air hole B (22).

2. The self-controlled purging valve for a positive pressure dense phase pneumatic conveying pipeline according to claim 1, characterized in that: The first blow-assisted valve assembly (3) includes a valve stem A (31) located inside the valve seat (1). A spring A (32) is sleeved on the bottom of the valve stem A (31). A lower valve core (33) is sleeved on the outer wall of the valve stem A (31) near the bottom. The lower valve core (33) is wrapped around the spring A (32). A lower end cover (34) is slidably connected to the outer wall of the lower valve core (33). The lower end cover (34) is sealed to the bottom center of the valve seat (1). The two ends of the spring A (32) abut against the opposite surfaces of the lower end cover (34) and the lower valve core (33), respectively, driving the valve stem A (31) to move the lower valve core (33) to realize the connection and blockage of the air outlet (12) and the air inlet (11).

3. The self-controlled purging valve for a positive pressure dense phase pneumatic conveying pipeline according to claim 2, characterized in that: The upper valve core (35) is sleeved on the outer wall of the valve stem A (31) near the middle position, and a spring B (36) is wrapped around the upper valve core (35) on the outer wall of the valve stem A (31). The upper end cover (37) is slidably connected to the outer wall of the upper valve core (35), and the upper end cover (37) is fixed inside the valve seat (1) by a retainer (38). The two ends of the spring B (36) are respectively pressed against the opposite surfaces of the upper end cover (37) and the upper valve core (35). The top of the valve stem A (31) passes through the upper end cover (37), and the end face of the valve stem A (31) is locked with a piston A (39) by a nut, which drives the valve stem A (31) to move the upper valve core (35) to realize the connection and blockage of the air outlet (12) and the exhaust port (13).

4. The self-controlled purging valve for a positive pressure dense phase pneumatic conveying pipeline according to claim 3, characterized in that: The valve seat (1) has an adapter groove at the top of the piston A (39) that is compatible with the piston A (39), and a through groove at the bottom of the adapter groove that connects to the air outlet (12).

5. The self-controlled purging valve for a positive pressure dense phase pneumatic conveying pipeline according to claim 1, characterized in that: The second blow valve assembly (4) includes a valve stem B (41) installed inside the valve cover (2). A guide hole (42) is provided in the middle of the valve stem B (41). Multiple sealing valve cores (43) are fixedly connected to the outer wall of the valve stem B (41) on one side of the guide hole (42). A spring C (44) is installed at one end of the valve stem B (41). A piston B (45) is sleeved near the other end of the valve stem B (41). A sealing cover (46) is installed at the other end of the valve stem B (41), and the sealing cover (46) is fixed to one side edge of the valve cover (2) by a retaining ring (47).

6. The self-controlled purging valve for a positive pressure dense phase pneumatic conveying pipeline according to claim 5, characterized in that: The valve cover (2) has a matching through groove at the sealing valve core (43) located near the middle. When the sealing valve core (43) is located in the through groove, the air hole (42) can be used to connect the air hole A (21) and the air hole B (22). The outer wall of the sealing valve core (43) is fitted with a sealing ring, and the sealing ring can fit against the inner wall of the valve cover (2) adjacent to the through groove.

7. The self-controlled purging valve for a positive pressure dense phase pneumatic conveying pipeline according to claim 6, characterized in that: The valve cover (2) has a matching movable groove inside the piston B (45), and the outer wall of the piston B (45) is smoothly attached to the inner wall of the movable groove. At the same time, the side wall of the movable groove has a vent hole that communicates with the outside.

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