Anti-deposition type pipeline static mixer for conveying powdery explosives

Abstract

The invention belongs to the technical field of powdery explosive conveying, and discloses an anti-deposition pipeline static mixer for powdery explosive conveying, which comprises two mixing pipes in longitudinal symmetry, a venturi accelerating pipe is communicated between the two mixing pipes, the top end of the upper mixing pipe is fixedly communicated with a feed port, and the top end of the lower mixing pipe is fixedly communicated with a discharge port. And the bottom end of the lower mixing pipe is fixedly communicated with a discharge port. All rotating shafts penetrating through the pipe wall are omitted, and a material leakage channel is eradicated from the physical structure. Even under the condition that equipment runs for a long time or internal pressure fluctuates, absolute sealing performance can be guaranteed, external impurities are prevented from polluting explosives, meanwhile, harm to the environment and operators caused by explosive dust leakage is eradicated, in addition, magnetic transmission has an overload protection function, and when internal material resistance is increased abnormally, the explosive dust is prevented from leaking out. And the inner and outer magnetic rings slip, so that power transmission is automatically cut off, and dual safety guarantee is provided for a high-risk production environment.

Description

Technical Field

[0001] This invention belongs to the field of powdered explosives conveying technology, specifically an anti-deposition type pipeline static mixer for conveying powdered explosives. Background Technology

[0002] In the production of powdered explosives (such as expanded ammonium nitrate explosives and modified ammonium nitrate explosives), mixing and conveying are key processes that determine product performance. Traditional production processes often use screw conveyors or static mixers to achieve material mixing and transport. Static mixers are widely used due to their lack of moving parts and low maintenance costs. However, existing pipeline mixing technologies face severe challenges when handling powdered explosives that are viscous, prone to moisture absorption and clumping, and have extremely high safety requirements.

[0003] In existing technologies, conventional static mixers primarily rely on the pressure energy of the fluid itself to passively divide and recombine through mixing units fixed within the pipe. This passive mixing method, when handling powdered explosives with high density or poor flowability, easily leads to the formation of a laminar boundary layer on the inner wall and bottom of the pipe. Due to the lack of radial active disturbance, heavier components tend to gradually deposit at the bottom of the pipe under gravity, resulting in uneven mixing and "dead zones." As operating time increases, the deposit layer thickens, not only reducing the effective flow cross-section of the pipe but also potentially causing explosive component segregation, severely affecting the detonation performance of the final product. Furthermore, to address the power supply issue, existing equipment typically uses mechanical shafts to drive internal components. However, mechanical shaft seals inevitably wear under long-term high-speed operation. For flammable and explosive powdered explosives, leakage of the shaft seal or the generation of high-temperature sparks due to friction can trigger catastrophic safety accidents.

[0004] Furthermore, to improve mixing efficiency and flow rate, some improved equipment incorporates a Venturi tube structure to accelerate the fluid using Bernoulli's principle. However, the throat of the Venturi tube, as the constriction point of the entire flow channel, is the weakest link in terms of material throughput. When conveying powdered explosives, the material's own moisture, static electricity, or agglomeration characteristics can easily cause bridging and blockage at the throat's diameter change. Existing handling methods typically require shutdown for disassembly and cleaning or backflushing with high-pressure gas. This not only leads to production interruptions and reduces efficiency but also increases the risk of workers coming into contact with hazardous materials due to frequent disassembly and assembly operations. Summary of the Invention

[0005] The purpose of this invention is to provide a sediment-resistant pipeline static mixer for conveying powdered explosives, in order to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a static pipeline mixer for conveying powdered explosives with anti-deposition properties, comprising two symmetrical mixing pipes connected by a Venturi accelerator tube, a feed inlet fixedly connected to the top of the upper mixing pipe, and a discharge outlet fixedly connected to the bottom of the lower mixing pipe. The device adopts a structure combining magnetic coupling transmission and mechanical linkage unblocking. A transmission component for non-contact torque transmission is provided at the port of the mixing pipe. Inside the mixing pipe, a spiral mixing blade is provided that revolves around an axis driven by the transmission component. An operating component is provided on the outer side of the mixing pipe. One end of the operating component is connected to the transmission component, and the other end extends to the throat of the Venturi accelerator tube and is connected to a unblocking rod that can radially penetrate into the pipe, thereby forming a closed anti-deposition and anti-clogging mixing system.

[0007] As a further technical solution of the present invention, the spiral mixing blade is designed as a double-headed spiral structure, including two spiral bodies arranged coaxially and nested with interlaced blades. The two spiral bodies are symmetrically distributed in the circumferential direction, and the top of each spiral mixing blade is connected to a mounting base. The revolution motion relative to the central axis of the tube is realized through the connection between the mounting base and the transmission component.

[0008] As a further technical solution of the present invention, a locking shaft, which serves as a stator, is fixed at the axial center of both the upper and lower mixing tubes. The locking shaft passes through the central cavity of the spiral mixing blade, and an installation shaft is provided at the end of the locking shaft that is closer to the Venturi accelerator tube. A locking frame fixed to the inner wall of the mixing tube is sleeved on the installation shaft, thereby providing a rotational support reference for the spiral mixing blade.

[0009] As a further technical solution of the present invention, a limiting ring groove is formed on the outer side of the locking shaft near the top end, and the transmission assembly includes a transmission seat connected to the mounting seat. A synchronizing rod extends from the transmission seat, and a limiting ball that can be embedded in the limiting ring groove and roll along it is installed at the end of the synchronizing rod.

[0010] As a further technical solution of the present invention, the transmission component adopts an inner and outer magnetic ring coupling structure, including a lower magnetic ring installed on the top of the transmission seat, and an upper magnetic ring that is movably snapped onto the outside of the mixing tube port and adsorbed to the lower magnetic ring through the tube wall. The rotation of the upper magnetic ring drives the lower magnetic ring inside the tube to rotate synchronously, thereby realizing shaftless power transmission.

[0011] As a further technical solution of the present invention, the transmission assembly also includes a transmission gear ring sleeved on the outer side of the feed inlet or discharge outlet. A driven gear is installed at the top of the upper magnetic ring, and the outer tooth surface of the transmission gear ring meshes with the driven gear. The rotation of the transmission gear ring drives multiple upper magnetic rings in a unified manner.

[0012] As a further technical solution of the present invention, the control assembly includes a control lever mounted on the side wall of the mixing tube via a limiting lug. An active transmission gear is fixed at the end of the control lever, which meshes with the transmission gear ring, thereby driving the internal spiral mixing blades to operate by rotating the control lever.

[0013] As a further technical solution of the present invention, the control component integrates a gear and rack conversion mechanism in the middle position, including an active operating gear fixedly sleeved on the control lever, and two parallel transmission racks located on both sides of the active operating gear and meshing with it, for converting rotational motion into linear motion of the two transmission racks moving towards or away from each other.

[0014] As a further technical solution of the present invention, the unblocking rod is fixedly installed at the end of the transmission rack, and the two unblocking rods are arranged symmetrically, which can be radially inserted into the center of the flow channel from both sides of the Venturi acceleration tube throat. The unblocking rod and the tube wall adopt a sliding sealing fit.

[0015] As a further technical solution of the present invention, an anti-detachment ring is fixedly sleeved at one end of the unblocking rod inside the Venturi accelerator tube. The outer diameter of the anti-detachment ring is larger than the installation hole diameter through which the unblocking rod passes through the pipe wall, so as to prevent the unblocking rod from accidentally detaching from the pipe when it is withdrawn outward.

[0016] The beneficial effects of this invention are as follows:

[0017] 1. This invention employs magnetic coupling transmission technology, placing the power transmission mechanism entirely outside the conveying pipeline. The strong magnetic attraction between the upper magnetic ring outside the pipe and the lower magnetic ring inside achieves cross-wall torque transmission, making the mixing pipe a completely sealed pressure vessel. This eliminates all rotating shafts penetrating the pipe wall, physically eradicating any channels for material leakage. Even during long-term operation or under fluctuating internal pressure, absolute sealing is guaranteed, preventing external impurities from contaminating the explosives. It also eliminates the harm to the environment and operators caused by explosive dust leakage. Furthermore, the magnetic transmission has overload protection; when internal material resistance abnormally increases, the inner and outer magnetic rings slip, automatically cutting off power transmission, providing double safety assurance for high-risk production environments.

[0018] 2. This invention utilizes a coaxial double-headed spiral mixing mechanism. This mechanism is not static; when sedimentation needs to be prevented, it revolves around a central axis under magnetic drive. The rotating double spiral blades create a forced three-dimensional circulating flow field. The helix angle design of the spiral blades provides axial lifting force to the material, continuously lifting heavy particles settled at the bottom of the pipe and re-entering the mainstream mixing zone, thus counteracting the gravitational settling effect. The outer edge of the blades closely follows the pipe wall, acting like a "scraper" to continuously peel off the deposits on the pipe wall boundary layer, completely eliminating dead zones. This ensures that the material is in a state of intense turbulence and shearing every moment it flows through the pipe, greatly improving the dispersion and uniformity of the mixture. At the same time, to solve the stability problem of the long cantilever spiral blades during rotation, a central locking shaft is used as the stator. The limiting ball on the transmission component rolls within the annular groove of the locking shaft, forming a reliable internal support structure. This ensures that the spiral blades can cover the entire flow channel cross-section and effectively counteracts the radial oscillation generated when stirring high-viscosity materials, ensuring the stability and durability of the equipment operation.

[0019] 3. This invention utilizes a single rotary power source, through the meshing of a drive gear and double-sided racks, to drive two unblocking rods in precise and synchronized motion, radially penetrating from both sides of the venturi throat. This symmetrical physical puncture action directly targets the most severely blocked core area, rapidly disrupting the arch structure formed by powder material due to compression, moisture, or electrostatic adsorption. Compared to traditional high-pressure backflushing, mechanical unblocking is not limited by the permeability of the powder, making it more direct and reliable. Compared to shutdown cleaning, this operation can be completed online without disassembling the pipe or interrupting the main airflow, greatly improving production continuity. Furthermore, the unblocking rods and pipe wall employ a sliding seal, and the ends are equipped with anti-detachment rings, ensuring that the high-pressure environment inside the pipe is not disrupted during unblocking and preventing the unblocking rods from accidentally falling into the mixing machine and causing secondary accidents. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 This is a separate schematic diagram of the structure of the manipulation component of the present invention;

[0022] Figure 3 This is a cross-sectional schematic diagram of the internal structure of the Venturi accelerator tube of the present invention;

[0023] Figure 4 This is a cross-sectional schematic diagram of the internal structure of the hybrid tube and Venturi accelerator tube of the present invention;

[0024] Figure 5 This is a schematic diagram showing the engagement of the two helical mixing blades of the present invention;

[0025] Figure 6 This is an exploded view of the two helical blades of the present invention;

[0026] Figure 7 This is a schematic diagram illustrating the cooperation between the locking shaft and the transmission assembly structure of the present invention;

[0027] Figure 8 This is an exploded view of the locking shaft and transmission assembly structure of the present invention;

[0028] Figure 9 This is a cross-sectional schematic diagram of the hybrid tube structure of the present invention.

[0029] In the diagram: 1. Mixing tube; 2. Venturi accelerator tube; 3. Unblocking rod; 4. Anti-detachment ring; 5. Feed inlet; 6. Discharge outlet; 7. Locking shaft; 8. Locking frame; 9. Spiral mixing blades; 10. Mounting base; 11. Control assembly; 111. Limiting lug; 112. Control lever; 113. Drive transmission gear; 114. Driven operating gear; 115. Transmission rack; 12. Transmission assembly; 121. Transmission seat; 122. Synchronizing rod; 123. Limiting ball; 124. Lower magnetic ring; 125. Upper magnetic ring; 126. Driven gear; 127. Transmission gear ring; 13. Limiting ring groove; 14. Mounting shaft. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] like Figures 1 to 9 As shown, this embodiment of the invention provides a static pipeline mixer for conveying powdered explosives with anti-deposition properties, including two symmetrical mixing pipes 1 connected by a Venturi accelerator pipe 2. The Venturi accelerator pipe 2 is designed to be thin in the middle and thick at both ends. The top of the upper mixing pipe 1 is fixedly connected to a feed inlet 5, and the bottom of the lower mixing pipe 1 is fixedly connected to a discharge outlet 6.

[0032] The feed inlet 5 is used for inputting powdered explosives and other materials, while the discharge outlet 6 is used for outputting the mixed materials. To increase mixing and transmission efficiency, the powdered explosives and other materials can be mixed with external high-pressure air and input into the feed inlet 5.

[0033] The middle of the upper and lower mixing tubes 1 is provided with a locking shaft 7, and the outer side of the locking shaft 7 is provided with two spiral mixing blades 9. The two spiral mixing blades 9 are arranged coaxially and nested with each other, with their blades interlacing. That is, the blade of one spiral extends into the pitch gap of the other spiral. The two are distributed at 180 degrees in the circumferential direction, thus forming a double-headed spiral structure. Both spiral mixing blades 9 can rotate relative to the locking shaft 7.

[0034] As the core spiral flow guide component of the static mixer, the spiral mixing blade 9 utilizes its coaxial nested double-headed spiral structure to construct a continuous and interlaced spiral flow channel in the pipeline. It mainly plays the roles of forced diversion, radial mixing, and shear dispersion. When the material flows through this component, the spiral mixing blade 9 forces the material to abandon linear motion and instead rotate and propel it along the blade surface. This process first generates strong centrifugal and centripetal motion, causing frequent radial displacement of the fluid at the center of the pipe and the pipe wall, effectively breaking the laminar boundary layer and enhancing heat transfer.

[0035] Secondly, the interlaced structure of the double helix continuously physically cuts and separates the material, and uses the velocity gradient between the flow layers to generate shear force, thereby achieving micro-dispersion and homogenization of multiphase fluids.

[0036] Finally, the full-section spiral sweeping flow eliminates dead zones inside the pipe and uses the material's own scouring force to prevent powder from depositing at the bottom of the pipe, thus ensuring a high degree of uniformity in the distribution of material composition, temperature, and flow rate without moving parts.

[0037] Among them, the upper and lower locking shafts 7 are respectively installed with mounting shafts 14 at their relatively close ends. The outer side of the mounting shaft 14 is fixedly sleeved with a locking frame 8, and the two ends of the locking frame 8 are fixed to the inner side wall of the mixing tube 1.

[0038] The Venturi accelerator tube 2 is located in the middle section of the device. As a key throttling element connecting the upper and lower spiral components, its core function is to use fluid dynamics to achieve accelerated material transport and turbulent premixing. When the material enters the contraction section of the tube from the upper cavity, the flow cross-section decreases sharply. According to Bernoulli's principle, this forces the material velocity to increase significantly and form a high-speed jet. This physical acceleration process generates a strong axial scouring force, which can effectively prevent the powder material from settling, accumulating, or bridging in the transition zone of the variable diameter, solving the clogging problem that is prone to occur in vertical transport. Subsequently, when the high-speed material enters the expansion section through the throat, the expansion of the cross-section leads to a decrease in flow velocity and a rebound in pressure, inducing strong boundary layer separation and micro-vortices. This not only further disperses the agglomerated particles in the material, but also provides a high-kinetic-energy initial turbulent state for entering the mixing tube 1 in the lower part, thereby significantly improving the mixing efficiency and safety of the overall device.

[0039] In order to ensure that the throat of the Venturi accelerator tube 2 can effectively break up the soft agglomerates of powdered explosives without generating excessive pressure loss and temperature rise, the optimal relationship between the necking ratio of the Venturi tube throat and the critical fragmentation energy is limited.

[0040] Specifically, when the gas-powder two-phase flow passes through the throat, the maximum turbulent shear stress generated should satisfy the following relationship:

[0041]

[0042] in, The coefficient of fluid friction is 0.02-0.04 for powdered explosives. The average density of the gas-powder mixture The inlet velocity is (m / s). The inlet diameter of the Venturi tube. The diameter of the throat. The critical cohesive strength (Pa) of the powdered explosive agglomerate to be transported.

[0043] Furthermore, to prevent excessive frictional heat from exceeding the safety threshold due to high flow velocity, the length L of the throat and the diameter of the throat are... Limited to Within this range, the residence time of the fluid in the throat is sufficient to disintegrate the aggregates and allow it to quickly enter the expansion section to restore pressure, thus avoiding localized heat accumulation.

[0044] A mounting base 10 is installed on one side of the top of the spiral mixing blade 9, and a transmission component 12 is installed on the top of the mounting base 10. Meanwhile, a limiting ring groove 13 is opened on the outer side of the locking shaft 7 near the top. The end of the transmission component 12 away from the spiral mixing blade 9 is movably engaged with the limiting ring groove 13.

[0045] The outer side of the mixing tube 1 is provided with an operating component 11, and the upper and lower ends of the operating component 11 are connected to the upper and lower transmission components 12.

[0046] The control assembly 11 includes two symmetrically arranged upper and lower limit ears 111, which are respectively connected to the outer surfaces of the upper and lower mixing tubes 1. A control lever 112 is movably sleeved between the upper and lower limit ears 111. Both ends of the control lever 112 are equipped with active transmission gears 113. The two active transmission gears 113 are meshed with the transmission assembly 12. An active operating gear 114 is fixedly sleeved in the middle of the control lever 112. Transmission racks 115 are symmetrically arranged on both sides of the outer surface of the active operating gear 114. The two transmission racks 115 are arranged parallel to each other, and their inner tooth surfaces are meshed with the two sides of the active operating gear 114, thus forming a gear and rack linkage mechanism to convert the rotational motion of the active operating gear 114 into synchronous linear motion of the two transmission racks 115 in opposite or opposite directions.

[0047] Two transmission racks 115 are each equipped with a unclogging rod 3 at the end near the Venturi accelerator tube 2, and an anti-detachment ring 4 is fixedly sleeved at the end of the unclogging rod 3 away from the transmission rack 115.

[0048] Two unblocking rods 3 are arranged in parallel and are inserted radially through the side wall of the throat of the Venturi accelerator tube 2. The unblocking rods 3 form a sliding seal with the wall of the Venturi accelerator tube 2 so that the unblocking rods 3 can reciprocate radially to clear the throat blockage.

[0049] The unblocking rod 3 is provided with a multi-layer labyrinth seal or a packing seal with air blowing protection between it and the pipe wall to prevent explosive dust from entering the sliding gap.

[0050] Example: When the control lever 112 rotates, the active operating gear 114 fixedly sleeved on it rotates synchronously. Since the two sides of the active operating gear 114 are respectively engaged with two parallel transmission racks 115, the rotational motion of the gear is precisely converted into synchronous linear motion of the two transmission racks 115 in opposite directions or back directions. As the transmission racks 115 move, the unblocking rod 3 installed at its end is inserted into or withdrawn from the pipe radially through the mounting hole on the side wall of the throat of the Venturi accelerator tube 2 to unblock the pipe. At the same time, the anti-detachment ring 4 fixed at the end of the unblocking rod 3 plays a limiting and anti-detachment role to prevent the unblocking rod from accidentally falling off during the movement. In addition, the active transmission gears 113 at both ends of the control lever 112 are engaged with the transmission assembly 12 to realize the power transmission or locking of the overall mechanism.

[0051] The above embodiments solve the clogging problem that easily occurs in the variable diameter section of the static mixing device. Due to the sharp contraction of the throat section of the Venturi accelerator tube 2, the material is very likely to form bridges or deposits at this point. By adopting the structure of the active operating gear 114 driving the double-sided transmission rack 115, a single power source can drive two unblocking rods 3 to simultaneously penetrate the narrowest part of the throat from both sides. This synchronous opposing mechanical disturbance can quickly destroy the arch structure of the material, forcibly disperse the agglomerated material, and effectively clear the throat blockage. At the same time, the sliding seal between the unblocking rod 3 and the pipe wall not only ensures the smoothness of the mechanical action, but also prevents the leakage of high-pressure material in the pipe during the unblocking process. The setting of the anti-detachment ring 4 further improves the mechanical safety of the equipment and ensures the reliability of the device under long-term continuous operation.

[0052] It is worth noting that the above-mentioned methods for preventing deposition are only used when deposition occurs or periodically. Under normal conditions, the two spiral mixing blades 9 are in a static state, i.e., they are used as a conventional static mixer.

[0053] The transmission assembly 12 includes two symmetrically arranged transmission seats 121. The bottom end of the transmission seat 121 is connected to the top end of the mounting base 10. A synchronizing rod 122 is installed at the relatively close end of the two transmission seats 121. A limiting ball 123 is installed at the end of the synchronizing rod 122 away from the transmission seat 121. The limiting ball 123 is embedded in the inside of the limiting ring groove 13 and is movably engaged with it. The limiting ball 123 can rotate relative to the limiting ring groove 13. A lower magnetic ring 124 is installed at the top end of the transmission seat 121.

[0054] Meanwhile, two symmetrical annular grooves are opened at the ends of the two mixing pipes 1 near the feed inlet 5 or the discharge outlet 6. The lower magnetic ring 124 is movably engaged with the lower annular groove, while the upper annular groove is movably engaged with the upper magnetic ring 125. The lower magnetic ring 124 and the upper magnetic ring 125 are symmetrically arranged and mutually attracted. The top of the upper magnetic ring 125 is equipped with a driven gear 126. The transmission assembly 12 also includes a transmission gear ring 127 located on the outer side of the feed inlet 5 or the discharge outlet 6. The outer side of the transmission gear ring 127 is meshed with the two driven gears 126, and the rear end of the outer side of the transmission gear ring 127 is meshed with the driving transmission gear 113.

[0055] To prevent static electricity or sparks from being generated due to friction in flammable and explosive environments, the contact surfaces of the limiting ball 123 and the limiting ring groove 13 are made of non-sparking and wear-resistant materials such as antistatic ceramics, PEEK, or beryllium bronze. Furthermore, a powder self-lubricating channel is provided in the fit gap between the limiting ball 123 and the limiting ring groove 13, which uses the fluidity of the conveyed material itself to carry away the frictional heat.

[0056] Example: When the external control component 11 is activated, the active transmission gear 113 drives the transmission gear ring 127 and the upper magnetic ring 125 outside the tube to rotate synchronously. Utilizing the magnetic coupling effect, the upper magnetic ring 125 penetrates the wall of the mixing tube 1, attracting and dragging the lower magnetic ring 124 inside the tube to rotate coaxially. The rotation of the lower magnetic ring 124 directly drives the two left and right transmission seats 121 connected to it, thereby driving the mounting seat 10 at the bottom to rotate. The mounting seat 10, as the core bearing component, has two sets of nested spiral mixing blades 9 fixedly installed on it. When the mounting seat 10 is rotated under force, these two spiral mixing blades... The mixing blade 9 revolves around the central stationary locking shaft 7. During this process, the spiral mixing blade 9 utilizes its specific spiral angle structure to not only circumferentially shear the material, but also generate a continuous axial lifting force during rotation. Like a "screw conveyor", it continuously rolls up the material located at the edge and bottom of the pipe wall and pushes it towards the central flow channel. This active sweeping action effectively counteracts the material settling caused by gravity. At the same time, the synchronizing rod 122 connected to the transfer seat 121 rolls within the limiting ring groove 13 of the locking shaft 7 using the limiting ball 123, ensuring the stability of the trajectory of the entire rotating assembly.

[0057] The above embodiments combine magnetic drive with double-helix active anti-deposition to achieve safe and efficient handling of high-risk powdered explosives. Magnetic through-wall transmission replaces traditional mechanical shaft seals, eliminating the risk of dynamic seal leakage and ensuring the safety of transporting flammable and explosive materials. The transfer seat 121 drives the active rotation of the double-helix mixing blades 9, creating a dynamic flow field across the entire cross-section inside the pipe. The powerful sweeping and lifting action generated by the rotating helical mixing blades 9 can re-entrain heavy powders / particles attempting to deposit on the pipe wall or bottom into the main fluid in real time, completely eliminating the "dead zones" and "bottom deposition" phenomena commonly found in laminar mixing. This ensures the uniformity of the mixture during long-distance transport. The central locking shaft 7, in conjunction with the internal support structure of the limiting ball 123, effectively counteracts the radial oscillation generated when the long helical blades stir high-viscosity materials, significantly extending the equipment's service life.

[0058] The mixing mode of this device is oscillating mixing. When the control lever 112 reciprocates, the spiral blade 9 rotates in both directions within a certain angle to cut and disturb the material on the pipe wall. When unblocking is required, the control lever 112 rotates to the limit position and drives the unblocking rod 3 to penetrate.

[0059] To ensure that the helical mixing blade 9 can overcome the internal friction angle of the powdered explosive and achieve effective lifting, the transmission assembly 12 drives the helical mixing blade 9 to rotate at an angular velocity. This application defines a "critical transport factor for preventing deposition" K, which needs to be set within a specific range. The calculation formula is as follows:

[0060]

[0061] Where: R is the outer radius of the helical hybrid blade (m), α is the helix angle of the helical blade (°), and g is the acceleration due to gravity (9.8 m / s^2). K is the static friction coefficient between the powdered explosive and the pipe wall. When the K value is controlled between 1.2 and 1.8, the force state of the material at the pipe wall reaches the optimal balance, which can effectively overcome gravity to peel off the deposited layer (K>1) and avoid the powder being over-compacted on the pipe wall due to excessive centrifugal force to form a hard "pressure shell" (K<2).

[0062] The comparative experiment is as follows:

[0063] To verify the actual effect of the anti-deposition type pipeline static mixer described in this invention, the following experiment was conducted. The experimental material was a simulated powder with properties similar to expanded ammonium nitrate explosive (the main components were a mixture of modified starch and salt, with an average particle size of 150 μm and a bulk density of 0.85 g / cm³), and a continuous conveying and mixing test was carried out at an ambient temperature of 25°C.

[0064] Control group: Commercially available conventional static mixers (containing only fixed twisted blades, without an active spiral or Venturi diameter-changing unblocking function). Experimental group: The device described in the embodiments of this invention (containing a magnetically driven double spiral and a Venturi unblocking component).

[0065] All tests lasted 60 minutes and measured mixing uniformity (coefficient of variation, CV value), residual sediment in the pipe, and material temperature rise at the outlet. The data are recorded in the table below:

[0066]

[0067] Experimental Conclusion: Data shows that by introducing magnetically driven active spiral mixing and a venturi tube structure, the mixing uniformity was improved by approximately four times compared to traditional passive mixers when processing easily deposited powders, and the residue was reduced by more than 96%. Particularly noteworthy is that the temperature rise in the experimental group was only 0.8℃, far lower than the 4.2℃ in the control group. For heat-sensitive powdered explosives, this 3.4℃ temperature difference significantly improves the inherent safety of the production process.

[0068] Working principle and usage process of this invention:

[0069] 1. Start-up preparation and feeding equipment. After installation, ensure that the feed port 5 is sealed to the upstream feeding system and the discharge port 6 is connected to the downstream packaging or storage equipment. Start the external power source (not shown in the figure). At this time, the active transmission gear 113 connected to the external power source starts to rotate. The powdered explosive and the additives to be mixed enter the feed port 5 at the top of the upper mixing pipe 1 by pneumatic conveying or gravity dropping.

[0070] 2. The rotation of the active transmission gear 113 driven by the magnetic coupling drive drives the transmission gear ring 127 to rotate. The transmission gear ring 127 meshes with the driven gear 126 on the upper magnetic ring 125 assembly installed on the outside of the mixing pipe 1, driving the upper magnetic ring 125 to rotate around the axis of the mixing pipe 1. Utilizing the penetrability and coupling effect of magnetic flux, the upper magnetic ring 125 outside the pipe tightly attracts the lower magnetic ring 124 inside the pipe through magnetic attraction, driving the lower magnetic ring 124 to rotate synchronously. This process realizes contactless power transmission and ensures complete isolation between the inside of the pipe and the external environment.

[0071] 3. Regularly prevent sedimentation. The rotation of the lower magnetic ring 124 drives the internal mounting base 10 to rotate through the transmission seat 121. The mounting base 10 drives two coaxial, nested spiral mixing blades 9 to revolve around the central locking shaft 7.

[0072] Radial shearing and axial lifting: During the rotation of the spiral mixing blade 9, the powdered explosive entering the mixing tube 1 is subjected to strong shearing and stirring, and the double spiral structure continuously divides and changes the direction of the material;

[0073] Eliminating dead zones: The outer edge of the spiral blades sweeps against the inner wall of the mixing pipe 1, forcibly rolling up and pushing the material that is trying to deposit on the pipe wall and bottom towards the central flow channel, thus preventing material settling.

[0074] Stable support: During rotation, the limiting ball 123 at the end of the synchronizing rod 122 extending from the transmission seat 121 rolls in the limiting ring groove 13 of the locking shaft 7, providing radial support for the long-span spiral assembly and preventing swaying caused by rotational centrifugal force;

[0075] 4. Venturi acceleration and turbulent premixing: The material initially mixed in the upper mixing tube 1 enters the middle Venturi acceleration tube 2. As the tube diameter narrows, according to Bernoulli's principle, the material flow rate increases sharply and the pressure decreases. The high-speed air-powder flow forms a jet at the throat, breaking up any possible soft agglomerates. After passing through the throat, the tube diameter expands again, the flow rate decreases and the pressure rises, generating micro-vortices, which further improves the mixing uniformity. Subsequently, the material enters the lower mixing tube 1 for secondary mixing.

[0076] 5. Online unblocking: If abnormal flow monitoring is detected during operation or if it is determined that there is a blockage in the throat of the Venturi accelerator tube 2, the operator will control the system drive control component 11 to work.

[0077] Action trigger: Rotate the control lever 112, which drives the active operating gear 114 fixed thereon to rotate;

[0078] Linear conversion: The active operating gear 114 drives the meshing transmission racks 115 on both sides to move inward simultaneously;

[0079] Arch breaking and unblocking: The transmission rack 115 pushes the two unblocking rods 3 radially into the throat of the Venturi accelerator tube 2. The two unblocking rods 3 intersect or penetrate at the center of the throat, physically destroying the arch bridge structure formed by the material.

[0080] Reset: Rotate the control lever 112 in the opposite direction, and the unblocking lever 3 will exit the flow channel. Under the action of the anti-detachment ring 4, it will be prevented from detaching. The crushed clumps will pass through quickly under the action of airflow and normal conveying will be restored.

[0081] 6. Material discharge: The uniform material, after undergoing two-stage active spiral mixing and one-stage Venturi turbulent mixing, finally converges at the bottom discharge port 6 and is discharged, completing the entire conveying and mixing process.

Claims

1. A static pipeline mixer for conveying powdered explosives with anti-deposition properties, comprising two symmetrically arranged mixing pipes (1), a Venturi accelerator pipe (2) connecting the two mixing pipes (1), a feed inlet (5) fixedly connected to the top of the upper mixing pipe (1), and a discharge outlet (6) fixedly connected to the bottom of the lower mixing pipe (1), characterized in that: The device adopts a structure that combines magnetic coupling transmission and mechanical linkage unblocking. A transmission component (12) for non-contact torque transmission is provided at the port of the mixing tube (1). Inside the mixing tube (1), there is a spiral mixing blade (9) that is driven by the transmission component (12) to revolve around the axis. An operating component (11) is provided on the outer side of the mixing tube (1). One end of the operating component (11) is connected to the transmission component (12) for transmission, and the other end extends to the throat of the venturi accelerator tube (2) and is connected to a unblocking rod (3) that can be radially inserted into the tube, thereby forming a closed anti-deposition and anti-clogging mixing system.

2. The anti-deposition type pipeline static mixer for conveying powdered explosives according to claim 1, characterized in that: The spiral hybrid blade (9) is designed as a double-headed spiral structure, including two spiral bodies arranged coaxially and nested with interlaced blades. The two are symmetrically distributed at 180 degrees in the circumferential direction, and the top of each spiral hybrid blade (9) is connected to a mounting base (10). The connection between the mounting base (10) and the transmission component (12) enables the revolution motion relative to the central axis of the tube.

3. The anti-deposition type pipeline static mixer for conveying powdered explosives according to claim 2, characterized in that: The upper and lower mixing tubes (1) are both fixed with a locking shaft (7) as a stator. The locking shaft (7) passes through the central cavity of the spiral mixing blade (9). The locking shaft (7) is provided with a mounting shaft (14) at the end of the locking shaft (7) that is closer to the Venturi accelerator tube (2). A locking frame (8) fixed to the inner wall of the mixing tube (1) is sleeved on the mounting shaft (14), thereby providing a rotational support reference for the spiral mixing blade (9).

4. The anti-deposition type pipeline static mixer for conveying powdered explosives according to claim 3, characterized in that: The locking shaft (7) has a limiting ring groove (13) on its outer side near the top. The transmission assembly (12) includes a transmission seat (121) connected to the mounting seat (10). A synchronizing rod (122) extends from the transmission seat (121). A limiting ball (123) is installed at the end of the synchronizing rod (122) and can be embedded in the limiting ring groove (13) and roll along it.

5. The anti-deposition type pipeline static mixer for conveying powdered explosives according to claim 4, characterized in that: The transmission component (12) adopts an inner and outer magnetic ring coupling structure, including a lower magnetic ring (124) installed on the top of the transmission seat (121) and an upper magnetic ring (125) that is movably snapped onto the outside of the port of the mixing tube (1) and adsorbed to the lower magnetic ring (124) through the tube wall. The rotation of the upper magnetic ring (125) drives the lower magnetic ring (124) inside the tube to rotate synchronously, thus realizing shaftless power transmission.

6. The anti-deposition type pipeline static mixer for conveying powdered explosives according to claim 5, characterized in that: The transmission assembly (12) also includes a transmission gear ring (127) sleeved on the outer side of the feed inlet (5) or discharge outlet (6). The top of the upper magnetic ring (125) is equipped with a driven gear (126). The outer tooth surface of the transmission gear ring (127) meshes with the driven gear (126). The rotation of the transmission gear ring (127) drives multiple upper magnetic rings (125) in a unified manner.

7. The anti-deposition type pipeline static mixer for conveying powdered explosives according to claim 6, characterized in that: The control assembly (11) includes a control lever (112) mounted on the side wall of the mixing tube (1) via a limiting lug (111). The end of the control lever (112) is fixed with an active transmission gear (113), which meshes with the transmission gear ring (127), thereby driving the internal spiral mixing blades (9) to operate by rotating the control lever (112).

8. The anti-deposition type pipeline static mixer for conveying powdered explosives according to claim 7, characterized in that: The control assembly (11) integrates a gear and rack conversion mechanism in the middle position, including an active operating gear (114) fixedly sleeved on the control lever (112), and two parallel transmission racks (115) located on both sides of the active operating gear (114) and meshing with it, for converting rotational motion into linear motion of the two transmission racks (115) facing each other or away from each other.

9. The anti-deposition type pipeline static mixer for conveying powdered explosives according to claim 8, characterized in that: The unblocking rod (3) is fixedly installed at the end of the transmission rack (115), and the two unblocking rods (3) are arranged symmetrically. They can be radially inserted into the center of the flow channel from both sides of the throat of the Venturi accelerator tube (2). The unblocking rod (3) and the tube wall are fitted with a sliding seal.

10. The anti-deposition type pipeline static mixer for conveying powdered explosives according to claim 9, characterized in that: The end of the unblocking rod (3) inside the Venturi accelerator tube (2) is fixedly fitted with an anti-detachment ring (4). The outer diameter of the anti-detachment ring (4) is larger than the installation hole diameter through which the unblocking rod (3) passes through the pipe wall, in order to prevent the unblocking rod (3) from accidentally detaching from the pipe when it is pulled outward.

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