Dense-phase pneumatic conveying system for solid powder

Abstract

The invention provides a solid powder dense-phase pneumatic conveying system. The solid powder dense-phase pneumatic conveying system comprises a first plug forming device and a gas control unit. The top end of the first plug forming device receives upstream supplied materials, and the bottom end is communicated with a material conveying pipeline; the gas control unit is communicated with the first plug forming device through a first pipeline, and the gas control unit is communicated with the material conveying pipeline through a second pipeline; a first pneumatic butterfly valve is arranged on the first pipeline; and a second pneumatic butterfly valve is arranged on the second pipeline. By arranging the plug forming device, the corresponding pipelines and all the valves, the powder can form the material plug with the appropriate length when entering the conveying pipeline, the problem that in the prior art, due to the light self weight, the powder is not prone to deposition and plug forming is solved, and the problem that the material plug of a dense-phase conveying system is discontinuous and unstable in a horizontal pipeline is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of dense phase conveying chemical equipment, and in particular relates to a dense phase pneumatic conveying system for solid powder. Background Art

[0002] In existing chemical plants, some fragile or abrasive powders are transported by dense phase conveying. The existing powder dense phase conveying system uses the method of natural deposition of powder in the pipeline to form a plug. However, when the particle size of the powder is very small, that is, the average particle size is less than 0.5mm or even less than 0.1mm, its sedimentation rate will become very low, which makes it difficult for the powder to settle in the horizontal conveying pipeline to form a plug. Even if the conveying gas volume is very small, part of the powder settles to the bottom of the pipeline, but because the cross-sectional area of ​​the pipeline is reduced after the powder is deposited, the gas flow rate in the upper space will become faster, so the powder can still maintain a sufficient suspension speed in this area and not settle, making it difficult for the powder to form a plug in the horizontal pipeline for dense phase conveying.

[0003] In view of this, developing a pneumatic conveying system that can solve the problem of plugging during dense phase conveying of powders has become an urgent problem to be solved by those skilled in the art. Summary of the invention

[0004] The purpose of the present invention is to solve the difficulties existing in the above-mentioned prior art. By setting a plug-forming device, pipelines and various valves, the powder can form a plug of appropriate length throughout the entire process from entering the transportation pipeline to finally entering the silo. This solves the problem in the prior art that the powder is not easy to settle into a plug due to its light weight, and also solves the problem of discontinuous and unstable plugs in the horizontal pipeline of the dense phase conveying system.

[0005] The present invention is achieved through the following technical solutions:

[0006] A solid powder dense phase pneumatic conveying system, comprising:

[0007] The first plugging device has a top end receiving upstream material supply and a bottom end connected to a material conveying pipeline;

[0008] The gas control unit is connected with the first thrombus former through a first pipeline and connected with the material conveying pipeline through a second pipeline; a first pneumatic butterfly valve is arranged on the first pipeline; and a second pneumatic butterfly valve is arranged on the second pipeline.

[0009] In a preferred embodiment of the present invention, an air inlet pipe is provided on the side wall of the first thrombus forming device, and the air inlet pipe is tangentially connected to the side wall of the first thrombus forming device; the air inlet pipe is connected to the gas control unit through a first pipeline;

[0010] Preferably, the top surface of the first plug former is provided with a feed port for receiving upstream material supply, and the feed port is located on the leeward side of the blowing wind of the air inlet pipe.

[0011] In a preferred embodiment of the present invention, a central tube is provided at the axis of the first thrombin former; the top surface of the central tube is connected to the top surface of the first thrombin former, and the bottom surface of the central tube is suspended; a lateral opening is provided on the upper side surface of the central tube.

[0012] In a preferred embodiment of the present invention, the height of the lateral opening in the vertical direction is the same as the height of the air inlet pipe in the vertical direction; and / or

[0013] There are multiple lateral openings, and the multiple lateral openings are evenly distributed around the circumference of the central tube.

[0014] In a preferred embodiment of the present invention, a first material level meter port is provided on the side of the first thrombus former; the first material level meter port is connected to a first low material level switch, the first low material level switch is communicatively connected to the first pneumatic butterfly valve, and the first low material level switch is communicatively connected to the second pneumatic butterfly valve.

[0015] In a preferred embodiment of the present invention, a plurality of second thrombus formers connected in sequence are arranged on the material conveying pipeline; a connecting pipeline is arranged between two adjacent second thrombus formers; one end of the connecting pipeline is connected to the discharge port of the second thrombus former located upstream, and the other end of the connecting pipeline is connected to the conveying inlet pipe of the second thrombus former located downstream; an exhaust port is arranged at the top end of the second thrombus former, and a third pipeline is arranged between the exhaust port and the connecting pipeline; a third pneumatic butterfly valve is arranged on the third pipeline;

[0016] Preferably, the distance between the first thrombus-forming device and the second thrombus-forming device located most upstream is 5 to 10 times the preset material plug length; and / or

[0017] The distance between two adjacent second plug-forming devices is 5 to 10 times the preset plug length.

[0018] In a preferred embodiment of the present invention, the delivery inlet tube of the second thrombus former is tangentially connected to the side wall of the second thrombus former.

[0019] In a preferred embodiment of the present invention, a second material level meter port is provided on the lower side of the second thrombus former, the second material level meter port is connected to a second low material level switch, and the second low material level switch is communicatively connected to the third pneumatic butterfly valve.

[0020] In a preferred embodiment of the present invention, the second thrombus forming device is provided with a pressure transmitter, and the pressure transmitter is communicatively connected with the third pneumatic butterfly valve;

[0021] A plurality of gas access points are arranged at equal intervals on the connecting pipeline, and each of the gas access points is connected to the exhaust port through the third pipeline.

[0022] In a preferred embodiment of the present invention, the distance between two adjacent gas access points is 0.5 to 0.8 times the preset plug length. Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention arranges plugs at the powder discharge point and along the conveying pipeline, and cooperates with corresponding pipelines and various valves. On the one hand, the powder can form a plug of appropriate length from the time it enters the transportation pipeline to the time it finally enters the silo, that is, a continuous and stable plug flow is formed in the horizontal pipeline for dense phase transportation, which solves the problem of powder not being easy to deposit in the horizontal pipeline to form a plug and the problem of discontinuity of the plug in the prior art; on the other hand, the fluctuation range of the conveying pressure is also small, which ensures that the material moves at a low speed in the pipeline and the plug flow transportation is stable and continuous, thereby reducing material damage or pipeline wear. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of a dense phase pneumatic conveying system for solid powders of the present invention;

[0025] Figure 2 It is a front view of the first plugging device in the solid powder dense phase pneumatic conveying system of the present invention;

[0026] Figure 3 It is a top view of the first plug-forming device in the solid powder dense phase pneumatic conveying system of the present invention;

[0027] Figure 4 It is a front view of the second plug-forming device in the solid powder dense phase pneumatic conveying system of the present invention;

[0028] In the figure, 1-hopper, 2-rotary valve, 3-first thrombus former, 4-silo, 5-material conveying pipeline, 6-gas control unit, 7-first pneumatic butterfly valve, 8-second pneumatic butterfly valve, 9-first low material level switch, 10-third pneumatic butterfly valve, 11-second thrombus former, 12-second low material level switch, 13-pressure transmitter, 21-cylinder, 22-upper head, 23-cone, 24-center tube, 25-feed port, 26-discharge port, 27-inlet pipe, 28-level meter port, 29-exhaust port, 30-dynamic material level surface, 31-lateral opening, 32-pressure transmitter port, 33-conveying inlet pipe. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0030] like Figure 1 As shown, the present invention provides a solid powder dense phase pneumatic conveying system for conveying solid powder from a hopper 1 to a silo 4. The solid powder dense phase pneumatic conveying system comprises a first thrombus former 3, a material conveying pipeline 5, a gas control unit 6, a second thrombus former 11 and corresponding pneumatic valves.

[0031] The first thrombus former 3 is arranged below the hopper 1, and the two are connected. Preferably, a rotary valve 2 is provided between the hopper 1 and the first thrombus former 3, which is a valve with an impeller arranged inside. After the powder enters one end of the valve body of the rotary valve 2 from the hopper 1, it will reach the discharge position at the other end as the impeller rotates, and then enters the first thrombus former 3 under the action of gravity. The rotary valve 2 can realize continuous unloading due to the continuous rotation of its impeller and the valve cavity to form a seal. Compared with the intermittent unloading in the prior art that relies on a single sending tank (which needs to be controlled by opening and closing the stop valve), the present invention can improve the feeding efficiency and thus improve the conveying efficiency. In addition, the rotary valve 2 is easy to control, which avoids the problems of increased installation height and complex control caused by parallel or series sending tanks.

[0032] The structure of the first thrombus forming device 3 is as follows Figure 2 and 3 As shown, it includes a hollow thrombus former tank body, a central tube 24, a feed port 25, a discharge port 26, and an air inlet pipe 27. The thrombus former tank body of the first thrombus former 3 includes three parts, which include an upper head 22, a hollow cylindrical barrel 21 and a hollow cone 23 from top to bottom, and the three are interconnected and coaxially arranged. The feed port 25 is arranged at the top of the thrombus former tank body and is connected to the rotary valve 2. The powder in the hopper 1 enters the first thrombus former 3 through the feed port 25 after passing through the rotary valve 2. After the powder enters the first thrombus former 3, it will fall into the cone 23 at the bottom under the action of gravity. A discharge port 26 is provided on the bottom surface of the cone 23, and the discharge port 26 is connected to the material conveying pipeline 5 to transfer the powder in the cone 23 into the material conveying pipeline 5.

[0033] It should be noted that the powder is a solid material and will not be automatically transported from the first thrombus former 3 to the material conveying pipeline 5 without power.

[0034] An air inlet pipe 27 is provided on the side of the cylinder 21 in the first thrombus former 3. The air inlet pipe 27 is connected to the gas control unit 6, and specifically, the two are connected through the first pipeline. The gas control unit 6, namely the Air Control Unit, referred to as ACU, is the core component of the dense phase pneumatic conveying system of solid powder, which is mainly used to provide compressed gas. On the first pipeline, a first pneumatic butterfly valve 7 is provided. On the one hand, it adjusts the flow rate and pressure of the gas delivered to the first thrombus former 3, thereby adjusting the thrombus formation of the powder in the first thrombus former 3; on the other hand, it can control the opening and closing of the first pneumatic butterfly valve 7 to control whether the compressed gas is delivered to the first thrombus former 3.

[0035] In a preferred embodiment of the present invention, Figure 3 As shown, the air inlet pipe 27 is tangentially connected to the side wall of the cylinder 21. The compressed gas enters the thrombus-forming tank body tangentially, which is conducive to driving the powder to be uniformly deposited around the thrombus-forming tank body through the circumferential rotation of the airflow itself, avoiding the accumulation of powder on one side of the thrombus-forming tank body and causing leakage on the other side and then destroying the thrombus; on the other hand, the compressed gas reduces its wind force under the blocking and friction of the inner wall of the thrombus-forming tank body, thereby reducing its ability to blow away the powder, which is conducive to improving the thrombus-forming efficiency.

[0036] In a more preferred embodiment of the present invention, Figure 3 As shown, the feed port 25 of the first thrombus former 3 is located on the leeward side of the blowing wind of the air inlet pipe 27. Specifically, because the air inlet pipe 27 is tangentially connected to the side wall of the cylinder 21, the blowing wind of the air inlet pipe 27 will form a windward side and a leeward side when entering the thrombus former tank body. When viewed from the top, the airflow blown from the air inlet pipe 27 needs to rotate for almost one circle before it can blow to the location of the feed port 25. In this way, when the powder falls, it can be avoided as much as possible from being blown away by strong wind, which is conducive to the sedimentation and accumulation of the powder and the improvement of the thrombus forming efficiency. In addition, the tangential air intake of the air inlet pipe 27 not only reduces the wind force, but also the softened airflow is conducive to driving the powder to be uniformly accumulated around the thrombus former tank body through its own circumferential rotation, avoiding the problem that the powder accumulates on one side of the thrombus former tank body and causes leakage on the other side and then destroys the thrombus, which is conducive to improving the thrombus forming efficiency.

[0037] In a more preferred embodiment of the present invention, Figure 2 and 3As shown, a center tube 24 is provided at the central axis of the thrombin-forming tank body of the first thrombin-forming device 3. The top surface of the center tube 24 is connected to the upper head 22, and the bottom surface of the center tube 24 is suspended. In the vertical direction, the height of the bottom surface of the center tube 24 is between the top surface and the bottom surface of the cone 23. It should be particularly noted that the top surface of the center tube 24 is not open, and the bottom surface is open. A lateral opening 31 is provided on the upper side surface of the center tube 24, near the upper head 22. Compared with the solution of connecting the center tube 24 to the tank body using a circumferential bracket of the tube, the present invention "the top surface of the center tube 24 is connected to the thrombin-forming tank body, and the bottom surface of the center tube 24 is suspended", which can prevent the powder from being obstructed by the bracket when it rotates in a circle in the thrombin-forming tank body, and can also prevent the bracket from obstructing the airflow movement and generating turbulence.

[0038] In a preferred embodiment of the present invention, the height of the lateral opening 31 in the vertical direction is the same as the height of the air inlet pipe 27 in the vertical direction, which is conducive to the compressed gas entering the central tube 24, thereby improving the thrombogenic efficiency. The compressed gas enters the thrombogenic tank body tangentially from the air inlet pipe 27, and rotates counterclockwise along the side wall of the thrombogenic tank body. Under the condition of continuous gas supply by the gas control unit 6, a part of the rotation path of the compressed gas gradually moves toward the central tube 24, and then enters the central tube 24 through the lateral opening 31 opened thereon, and continues to move downward along the central tube 24, so that the powder located below it can be efficiently pushed into the discharge port 26; another part of the compressed gas will squeeze the dynamic material level surface 30 of the powder, promoting its movement toward the discharge port 26.

[0039] In a more preferred embodiment of the present invention, Figure 2 As shown, a plurality of lateral openings 31 are provided on the side wall of the central tube 24, and the plurality of lateral openings 31 are evenly distributed around the central tube 24, which can accelerate the time for the compressed gas to enter the central tube 24, further facilitate the compressed gas to enter the central tube 24, and thus improve the plugging efficiency. It should be particularly noted that the sum of the cross-sectional areas of the plurality of lateral openings 31 is substantially equal to the cross-sectional area of ​​the central tube 24, so as to facilitate the compressed gas to form a stable airflow in the central tube 24.

[0040] It should be emphasized that the bottom opening of the central tube 24 is located above the discharge port 26 and faces the discharge port 26. There is a vertical distance between the bottom surface of the central tube 24 and the discharge port 26, otherwise the powder is prevented from moving to the discharge port 26 and cannot be rotated out of the first plug forming device 3.

[0041] The discharge port 26 located at the bottom surface of the cone 23 in the first thrombus former 3 is connected to the material conveying pipeline 5. The material conveying pipeline 5 is also connected to the gas control unit 6. Specifically, the two are connected through a second pipeline. On the second pipeline, a second pneumatic butterfly valve 8 is provided to adjust the flow rate and pressure of the gas delivered to the material conveying pipeline 5, thereby adjusting the thrombus formation of the powder. It should be noted that the connection between the second pipeline and the material conveying pipeline 5 is close to the first thrombus former 3. As can be seen from the above, the gas output from the gas control unit 6 is divided into two paths: one path is connected to the first thrombus former 3 through the first pipeline, and the gas enters the first thrombus former 3, and the other path is connected to the material conveying pipeline 5 through the second pipeline, and the gas enters the material conveying pipeline 5.

[0042] The process of forming a plug by the powder in the first plug forming device 3 is as follows:

[0043] (1) Start the rotary valve 2, and the powder enters the first plug-forming device 3 from the hopper 1 through the feed port 25. Start the gas control unit 6, open the second pneumatic butterfly valve 8 and close the first pneumatic butterfly valve 7, and the compressed gas enters the connection between the second pipeline and the material conveying pipeline 5 from the gas control unit 6 to empty the material conveying pipeline 5.

[0044] It should be noted that the second pneumatic butterfly valve 8 has the function of, on the one hand, introducing compressed gas into the material plug to form a plug flow of one section of material plug and one section of gas, and on the other hand, is to push the existing material plug in the material conveying pipeline 5 to continue conveying forward. In this step, although the second pneumatic butterfly valve 8 is in the start-up state, since there is no material plug in the material conveying pipeline 5 at this time, the compressed gas moves directly to the downstream.

[0045] (2) As the incoming material from the hopper 1 gradually increases, the powder in the first thrombus former 3 accumulates to a preset height value, which is sufficient to form a volume of the preset material plug length. Then, the second pneumatic butterfly valve 8 is closed, and the first pneumatic butterfly valve 7 is started. The compressed gas enters the first thrombus former 3 from the gas control unit 6 through the first pipeline and the air inlet pipe 27. The compressed gas rotates counterclockwise along the side wall of the thrombus former tank, enters the central tube 24 through the lateral opening 31, and continues to move downward and then passes through the central tube 24. Under the dual effects of the compressed gas acting on the top surface of the powder in the first thrombus former 3 (i.e., the dynamic material level surface 30), and the gas ejected from the lower mouth of the central tube 24, the powder in the first thrombus former 3 moves downward, and finally the powder enters the material conveying pipeline 5 connected to the bottom of the first thrombus former 3.

[0046] (3) Since the powder enters the material conveying pipeline 5 connected below the first thrombus former 3, the vertical height of the powder in the first thrombus former 3 is less than the preset height value, the first pneumatic butterfly valve 7 is closed, the second pneumatic butterfly valve 8 is started, and the compressed gas continues to push the material plug forward at the position of the new material plug entering the material conveying pipeline 5. Since the first pneumatic butterfly valve 7 is closed, the compressed gas from the first pipeline no longer enters the first thrombus former 3, and the material in the first thrombus former 3 accumulates again.

[0047] (4) When the powder in the first thrombus forming device 3 accumulates to a preset height value, the first pneumatic butterfly valve 7 is started again and the second pneumatic butterfly valve 8 is closed.

[0048] In summary, the first pneumatic butterfly valve 7 and the second pneumatic butterfly valve 8 are opened and closed alternately, so that a section of material plugs and a section of compressed gas are alternately arranged in the material conveying pipeline 5 and conveyed to the right.

[0049] In a preferred embodiment of the present invention, a material level meter port 28 is provided on the side of the cone 23 in the first thrombus former 3, near the discharge port 26, and the material level meter port 28 is connected to the first low material level switch 9, and the first low material level switch 9 is communicatively connected to the first pneumatic butterfly valve 7 and the second pneumatic butterfly valve 8. The material level meter port 28 can monitor the material level of the powder, and the first low material level switch 9 controls the opening and closing of the first pneumatic butterfly valve 7 and the second pneumatic butterfly valve 8 according to the real-time material level.

[0050] It should be noted that, for the sake of distinction, the material level meter port 28 in the first thrombus former 3 is referred to as the first material level meter port, and the material level meter port 28 in the subsequent second thrombus former 11 is referred to as the second material level meter port.

[0051] For example, if the stock in the cone 23 is less than the weight of one plug, the first low material level switch 9 will alarm. When the first low material level switch 9 alarms, that is, the stock is less than the weight of one plug, the first pneumatic butterfly valve 7 is closed, and the stock in the cone 23 continues to accumulate; at the same time, the second pneumatic butterfly valve 8 is opened to continue the transportation of downstream materials. When the powder in the cone 23 accumulates to a preset height value, the second pneumatic butterfly valve 8 is closed again, and the first pneumatic butterfly valve 7 is opened at the same time. In the process of alternating opening and closing of the first pneumatic butterfly valve 7 and the second pneumatic butterfly valve 8, a continuous plug flow section in which a plug and a compressed gas are alternately arranged can be formed in the material conveying pipeline 5.

[0052] It should be noted that, in the initial feeding stage, the powder material in the first embolizer 3 is below the material level meter port 28. The material level meter port 28 will not be triggered to start until the powder material in the first embolizer 3 reaches the material level meter port 28; the material level meter port 28 alarm will be triggered only when the powder material is higher than the material level meter port 28 and then drops below the material level meter port 28.

[0053] It should be pointed out that the triggering of the alternating opening and closing actions of the first pneumatic butterfly valve 7 and the second pneumatic butterfly valve 8 does not necessarily rely on the first low material level switch 9, and the first low material level switch 9 may not be set and only rely on the estimation method of powder feeding. Because the conveying capacity of the rotary valve 2 for continuous feeding is certain, the reliability of this estimation method is very high. Specifically, the feeding amount is calculated based on factors such as the rotor volume, rotation speed, feeding efficiency, and stacking density of the rotary valve. However, the addition of the first low material level switch 9 can make the control more precise, avoiding the occasional interruption of the feeding system causing the length of the material plug to be less than the preset value, and then causing the powder to be blocked by the friction force at the bottom during transportation due to insufficient length of the material plug, resulting in the problem of failure to form a plug.

[0054] The preset plug length is a pre-determined value comprehensively formulated in combination with the conveying capacity of the system and the physical properties of the powder itself. Generally speaking, the higher the gas volume and pressure of the system power gas, and the finer the powder particle size, the longer the preset plug length should be. The present invention does not limit the preset plug length.

[0055] The material conveying pipeline 5 can be a hollow tube with a corresponding pressure bearing capacity. After a plug flow section, which is alternately provided with a material plug and a compressed gas, moves a certain distance, the length of the material plug may change under the dual effects of the friction at the bottom of the material conveying pipeline 5 and the thrust of the gas at the rear. It may be too short and loose, or too long after collecting the retained materials in front. This not only destroys the continuity of dense phase transportation, but also causes oscillation and fluctuation of the system pipeline, and in extreme cases, blockage may occur. Therefore, in a preferred embodiment of the present invention, at least one second plug-forming device 11 is provided on the material conveying pipeline 5.

[0056] In a more preferred embodiment of the present invention, the pipeline distance between the first thrombus former 3 and the second thrombus former 11 is preferably 5 to 10 times the preset plug length. If the spacing is less than 5 times the preset plug length, the thrombus formers will be too densely arranged, and the overall cost per unit transportation length will increase. However, if the spacing is higher than 10 times the preset plug length, the plug will easily become loose during transportation. The finer the powder particle size, the more likely this problem will occur. For powders with an average particle size of less than 0.1 mm, 10 times the preset plug length is already at the maximum economic state.

[0057] The structure of the second thrombus forming device 11 is as follows Figure 4 As shown, and can refer to Figure 3 As shown, it is generally similar to the structure of the first thrombus former 3, with the only differences being: first, the feed port 25 is changed to a pressure transmitter port 32; second, the air inlet pipe 27 is changed to a delivery inlet pipe 33; and third, an exhaust port 29 is added to the top surface of the center tube 24.

[0058] Specifically, a pressure transmitter port 32 is provided on the upper head 22. The pressure transmitter port 32 is connected to the pressure transmitter 13. The pressure transmitter 13 is used to monitor the pressure in the thrombus former tank. The delivery inlet pipe 33 is provided on the side wall of the cylinder 21 and is connected to the material delivery pipeline 5 provided upstream thereof to receive the powder and gas delivered from the first thrombus former 3. The exhaust port 29 is opened on the top surface of the central tube 24 so that the gas can be transferred out from the exhaust port 29.

[0059] In one preferred embodiment of the present invention, the delivery inlet pipe 33 of the second thrombus forming device 11 is tangentially connected to the side wall of the cylinder 21, which can be referred to Figure 3 The gas and powder mixture entering the thrombus forming tank falls into the cone 23 below along the inner wall of the thrombus forming tank under the action of centrifugal force and gravity for accumulation, which is beneficial to gas-solid separation, improves thrombus forming efficiency and improves transportation stability.

[0060] If the transport path is long, multiple second plugging devices 11 are preferably provided on the material transport pipeline 5 to ensure the continuity of dense phase transport. More preferably, the distance between two adjacent second plugging devices 11 is 5 to 10 times the preset material plug length.

[0061] The following is a detailed description of the two connected second thrombus formers 11. The material conveying pipeline 5 is provided between the first second thrombus former 11 and the second second thrombus former 11. In order to distinguish it from the aforementioned material conveying pipeline 5, this section of the material conveying pipeline 5 is hereinafter referred to as a connecting pipeline. Specifically, a connecting pipeline is provided between the discharge port 26 of the first second thrombus former 11 and the conveying inlet pipe 33 of the second second thrombus former 11. The connecting pipeline includes an inclined section and a horizontal section.

[0062] A third pipeline is provided between the connecting pipeline and the exhaust port 29 of the first second thrombus former 11 to transport the gas from the exhaust port 29 thereinto. A third pneumatic butterfly valve 10 is provided on the third pipeline, which, on the one hand, adjusts the flow rate and pressure of the gas transported to the connecting pipeline, thereby adjusting the thrombus formation of the powder in the connecting pipeline; on the other hand, the opening and closing of the third pneumatic butterfly valve 10 can be controlled to control whether the gas is transported to the connecting pipeline.

[0063] The process of powder forming plugs in the inclined section is as follows:

[0064] (1) The mixture of gas and powder enters the second plug-forming device 11 from the delivery inlet pipe 33. The compressed gas and the plug are separated, the compressed gas moves upward, and the plug moves downward and reaches the discharge port 26.

[0065] (2) Since there is compressed gas in the second thrombus former 11, the pressure on the top surface of the powder in the second thrombus former 11 is relatively high, and under the blowing action of the bottom of the central tube 24, the powder in the second thrombus former 11 is pushed into the material conveying pipeline 5, and the height of the top surface of the powder in the second thrombus former 11 decreases.

[0066] (3) When the vertical height of the powder in the second thrombus former 11 is less than the preset height value, the third pneumatic butterfly valve 10 is opened, and the compressed gas from the second thrombus former 11 reaches the connection between the material conveying pipeline 5 and the third pipeline through the exhaust port 29 and the third pipeline, and the material plug is divided into two sections from there, thereby pushing the material plug on the right side of the place forward.

[0067] (4) When the third pneumatic butterfly valve 10 is activated, the second plug-forming device 11 is still feeding. When the powder in the second plug-forming device 11 accumulates to a preset height value, the third pneumatic butterfly valve 10 is closed, and the compressed gas has nowhere to be released in the second plug-forming device 11, pushing the powder into the material conveying pipeline 5 again.

[0068] (5) When the powder in the second thrombus former 11 enters the material conveying pipeline 5 again, and when the vertical height of the powder in the second thrombus former 11 is again less than the preset height value, the third pneumatic butterfly valve 10 is opened, and the compressed gas from the second thrombus former 11 reaches the connection between the material conveying pipeline 5 and the third pipeline via the exhaust port 29 and the third pipeline, thereby pushing the newly formed material plug forward.

[0069] In summary, the third pneumatic butterfly valve 10 is opened and closed alternately, so that a section of material plugs and a section of compressed gas are alternately arranged in the material conveying pipeline 5 and conveyed forward.

[0070] A material level meter port 28 is provided on the lower side of the second plug former 11, and the material level meter port 28 is connected to the second low material level switch 12. The second low material level switch 12 is communicatively connected to the third pneumatic butterfly valve 10 to control the reformation of the plug. When the second low material level switch 12 in the first second plug former 11 alarms (when the height of the powder in the second plug former 11 in the vertical direction is less than the preset height value), that is, when the stored material is less than the weight of one plug, the third pneumatic butterfly valve 10 is opened to discharge the gas to the connecting pipeline through the exhaust port 29. The material continues to accumulate in the second plug former 11 without affecting the downstream powder transportation. After the powder height reaches the preset height value estimated by the transportation capacity, the third pneumatic butterfly valve 10 is closed. By alternately opening and closing the third pneumatic butterfly valve 10 through the second low material level switch 12, a continuous plug can be formed in the pipeline.

[0071] After being transported through a section of material conveying pipeline 5, the powder entering the thrombus former tank body of the second thrombus former 11 is basically discontinuous. It is not easy to calculate the weight of the material entering the thrombus former tank body by relying on the system transportation capacity. Therefore, setting a second low material level switch 12 can accurately judge the powder situation, and then more accurately control the opening and closing of the third pneumatic butterfly valve 10, so as to achieve a good re-thrombus forming effect.

[0072] It should be noted that, since the material plug is affected by gravity in the inclined section of the connecting pipeline and is also blocked by the friction of the bottom, it is easy to be retained in the inclined section, and the materials entering the horizontal section will also be piled up due to the accumulation of the inclined section, which will cause the pressure in the thrombus forming tank to exceed the threshold (that is, the real-time pressure is 1.1 to 1.2 times the maximum preset pressure). Therefore, on the one hand, the present invention provides a pressure transmitter 13, which is communicatively connected to the third pneumatic butterfly valve 10, so that when the pressure transmitter 13 alarms, the compressed gas in the thrombus forming tank is discharged through the exhaust port 29; on the other hand, on the connecting pipeline, a gas access point is provided every 0.5 to 0.8 times the preset material plug length, and each gas access point is connected to the exhaust port 29 through the third pipeline.

[0073] In this way, when the pressure transmitter 13 alarms, the third pneumatic butterfly valve 10 can be activated, and gas will be introduced into each gas access point, and then compressed gas will be introduced into the stacked long plugs at equal intervals, so that they will form a plug flow of appropriate length again. After the plug flow is formed, the powder will move forward section by section, and a continuous and stable conveying movement will be re-formed. With the discharge of the compressed gas in the second plug forming device 11, the pressure transmitter 13 will no longer alarm, and the third pneumatic butterfly valve 10 can be closed at this time. Figure 1 In the present invention, the arrangement of the various gas access points is only an exemplary description and does not constitute a limitation to the present invention.

[0074] It should be emphasized that the selection of the access point interval of 0.5 to 0.8 times the preset plug length is due to the greater resistance encountered in the inclined section. Therefore, in order to open the passage smoothly and as quickly as possible, the usual 1 times the preset plug length cannot be used. The smaller the spacing, the more conducive it is to clearing the pipeline; however, if it is set too densely, the length of the plug in the connecting pipeline will be insufficient, which will lead to the problem of difficulty in plugging the powder again.

[0075] It should be emphasized that the valves in the present invention, including the first pneumatic butterfly valve 7, the second pneumatic butterfly valve 8, and the third pneumatic butterfly valve 10, do not necessarily have to be in the form of pneumatic butterfly valves, as long as they are valves with control capabilities.

[0076] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0077] In the description of the present invention, unless otherwise specified, the terms "upper", "lower", "left", "right", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0078] The above technical solution is only one implementation mode of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the principles disclosed in the present invention, and it is not limited to the technical solution described in the above specific embodiments of the present invention. Therefore, the above description is only preferred and does not have a restrictive meaning.

Claims

1. A solid powder dense phase pneumatic conveying system, It is characterized in that include: The first plugging device has a top end receiving upstream material supply and a bottom end connected to a material conveying pipeline; The gas control unit is connected with the first thrombus former through a first pipeline and connected with the material conveying pipeline through a second pipeline; a first pneumatic butterfly valve is provided on the first pipeline; and a second pneumatic butterfly valve is provided on the second pipeline.

2. The solid powder dense phase pneumatic conveying system according to claim 1, Features: An air inlet pipe is provided on the side wall of the first thrombus forming device, and the air inlet pipe is tangentially connected to the side wall of the first thrombus forming device; the air inlet pipe is connected to the gas control unit through the first pipeline; Preferably, the top surface of the first plug former is provided with a feed port for receiving upstream material supply, and the feed port is located on the leeward side of the blowing wind of the air inlet pipe.

3. The solid powder dense phase pneumatic conveying system according to claim 2, Features: A central tube is provided at the axis of the first thrombin former; the top surface of the central tube is connected to the top surface of the first thrombin former, and the bottom surface of the central tube is suspended; a lateral opening is opened on the upper side surface of the central tube.

4. The solid powder dense phase pneumatic conveying system according to claim 3, Features: The height of the lateral opening in the vertical direction is the same as the height of the air inlet pipe in the vertical direction; and / or There are multiple lateral openings, and the multiple lateral openings are evenly distributed around the circumference of the central tube.

5. The solid powder dense phase pneumatic conveying system according to claim 1, Features: A first material level meter port is provided on the side of the first thrombus former; the first material level meter port is connected to a first low material level switch, the first low material level switch is communicatively connected to the first pneumatic butterfly valve, and the first low material level switch is communicatively connected to the second pneumatic butterfly valve.

6. The solid powder dense phase pneumatic conveying system according to any one of claims 1 to 5, Features: On the material conveying pipeline, a plurality of second thrombus formers connected in sequence are arranged; a connecting pipeline is arranged between two adjacent second thrombus formers; one end of the connecting pipeline is connected to the discharge port of the second thrombus former located upstream, and the other end of the connecting pipeline is connected to the conveying inlet pipe of the second thrombus former located downstream; an exhaust port is arranged at the top end of the second thrombus former, and a third pipeline is arranged between the exhaust port and the connecting pipeline; a third pneumatic butterfly valve is arranged on the third pipeline; Preferably, the distance between the first thrombus-forming device and the second thrombus-forming device located most upstream is 5 to 10 times the preset material plug length; and / or The distance between two adjacent second plug-forming devices is 5 to 10 times the preset plug length.

7. The solid powder dense phase pneumatic conveying system according to claim 6, Features: The delivery inlet tube of the second thrombin former is tangentially connected to the side wall of the second thrombin former.

8. The solid powder dense phase pneumatic conveying system according to claim 6, Features: A second material level meter port is provided on the lower side of the second plug former, the second material level meter port is connected to a second low material level switch, and the second low material level switch is communicatively connected to the third pneumatic butterfly valve.

9. The solid powder dense phase pneumatic conveying system according to claim 6, Features: The second thrombus forming device is provided with a pressure transmitter, and the pressure transmitter is communicatively connected with the third pneumatic butterfly valve; A plurality of gas access points are arranged at equal intervals on the connecting pipeline, and each of the gas access points is connected to the exhaust port through the third pipeline.

10. The solid powder dense phase pneumatic conveying system according to claim 9, Features: The distance between two adjacent gas access points is 0.5 to 0.8 times the preset plug length.

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