Screw-ejector bait delivery device

Abstract

The present application provides a spiral-eject bait conveying device, which comprises an ejecting mechanism and a horizontally arranged spiral feeder, the feeding end of the spiral feeder is provided with an upward-opening feeding port, and the discharging end is provided with a downward-opening discharging port; the ejecting mechanism comprises a fan and a feeding main pipe, the front end of the feeding main pipe is in communication with the air outlet of the fan, the feeding main pipe comprises coaxially arranged front and rear feeding pipes, a Venturi tube is connected between the two feeding pipes, a conical injection pipe with a large front end and a small rear end is sealingly embedded in the inlet end of the Venturi tube, and the Venturi tube is laterally connected with a bait inlet pipe before the contraction section, the bait inlet pipe is perpendicular to the Venturi tube or forms an acute angle with the front pipe section of the Venturi tube, the upper end of the bait inlet pipe is opposite to the discharging port of the spiral feeder, and a gap is left between the two. The present application has the advantages of low crushing, accurate metering and high conveying efficiency.

Description

Technical Field

[0001] This invention relates to the field of aquaculture feed conveying equipment, and particularly to a spiral-ejector feed conveying device. Background Technology

[0002] With the rapid expansion of factory-style recirculating aquaculture and intensive high-density aquaculture, the requirements for feed metering accuracy, conveying efficiency, and feed integrity in aquaculture feeding are continuously increasing. Currently, long-distance feed conveying mostly adopts positive pressure pneumatic conveying solutions, but the feeding and infeeding connection structure has three main technical defects: First, conventional spiral feeding devices do not have an airlock function, and when directly connected to positive pressure conveying pipelines, airflow backflow is prone to occur, disrupting the continuity and metering stability of feeding, and cannot be directly adapted to positive pressure pneumatic conveying systems; Second, when using a star-shaped discharge valve as an airlock feeding component, the squeezing action between the blades and the shell can easily cause feed breakage, increasing feed loss rate and generating powder debris that pollutes the aquaculture water, affecting the health of aquaculture organisms; Third, conventional Venturi ejector structures have limited flow velocity enhancement and insufficient ejector negative pressure, resulting in low feed conveying efficiency; moreover, when the inlet is directly connected to the feeding device, airflow fluctuations in the pipeline can easily interfere with feeding metering accuracy, failing to meet the requirements for precise feeding. Summary of the Invention

[0003] In view of the problems existing in the prior art, the present invention aims to provide a spiral-ejector bait conveying device to solve the problems of high bait breakage rate, inaccurate metering and low conveying efficiency in existing pneumatic bait conveying equipment.

[0004] To achieve the above objectives, this invention proposes a spiral-ejector bait conveying device, comprising a horizontally arranged spiral feeder with an upward-opening feed inlet at the feed end and a downward-opening discharge outlet at the discharge end; and an ejector mechanism comprising a fan and a feeding manifold, the front end of which is connected to the air outlet of the fan. The feeding manifold comprises two coaxially arranged feed pipes, a front and a rear, connected in series between the two feed pipes by a Venturi tube. The inlet end of the Venturi tube is internally sealed with a conical injection pipe that is larger at the front end and smaller at the rear end, and the Venturi tube is laterally connected to a bait inlet pipe before its contraction section. The bait inlet pipe is perpendicular to the Venturi tube or forms an acute angle with the front end section of the Venturi tube. The upper inlet of the bait inlet pipe faces the discharge outlet of the spiral feeder, with a gap between them.

[0005] In the above scheme: the conical injection pipe extends from the inlet end of the venturi tube to the inlet end face of the contraction section.

[0006] In the above scheme: the length of the conical spray pipe is 100mm and the diameter of the rear port is 20mm.

[0007] In the above scheme: the length of the constriction section of the venturi tube is 45mm, the diameter of the throat is 40mm, the length-to-diameter ratio of the throat is 1, and the length of the diffuser section is 60mm.

[0008] In the above scheme, the inner diameter of both the inlet and outlet ends of the venturi tube is 72mm.

[0009] In the above scheme: a feed hopper is connected to the feed inlet of the screw feeder, and a feed funnel is connected to the feed inlet of the bait inlet pipe. The feed hopper facilitates manual feeding or replenishment by automatic feeding equipment. The upper port diameter of the feed funnel is greater than or equal to the discharge port diameter of the screw feeder, which can effectively receive the bait falling from the discharge port, prevent the bait from splashing outside the bait inlet pipe, and reduce bait loss.

[0010] In the above scheme: the feeding pipe is a circular cross-section pipe, and the bait inlet pipe is a square cross-section pipe. The square cross-section bait inlet pipe can guide the bait to form a uniform planar material curtain into the circular air-material mixing chamber, making the material more evenly dispersed on the cross-section of the circular main channel, avoiding the material concentration problem at the center of the pipe that is prone to occur with circular feeding pipes; the bait has more sufficient contact with the high-speed airflow, and the air-material mixing is more uniform. The circular feeding pipe is a general standard pipe material, and the coaxial docking and sealing assembly technology with the Venturi tube is mature.

[0011] In the above solution: the bottom end of the feeding funnel is connected to a square connecting pipe, which is sleeved on the outside of the feeding end of the bait inlet pipe, thereby realizing the connection between the feeding funnel and the bait inlet pipe. The result is simple and easy to assemble.

[0012] In the above scheme: the feed inlet pipe and the front end section of the Venturi tube are set at a 60° angle. 60° is an acute angle tilted forward along the airflow direction, creating a small, forward-facing angle between the feed direction and the main high-speed airflow direction. This avoids the strong shearing effect of a direct, hard impact between the material and the airflow during vertical feeding. Simultaneously, the feed can smoothly flow into the main channel along the inclined pipe wall, significantly reducing the impact and rebound of particles against pipe corners and walls. This angle significantly weakens the impact load on the feed, effectively reducing the particle breakage rate.

[0013] The beneficial effects of this invention are:

[0014] 1. A screw feeder ensures continuous and stable feeding. The screw pushing process has weak shearing action and no hard extrusion. Furthermore, a Venturi ejector negative pressure structure replaces traditional moving airlock components such as star-shaped discharge valves, eliminating mechanical extrusion throughout the process and significantly reducing feed breakage rate, thus minimizing feed loss and water pollution risks. 2. The screw feeder can achieve quantitative feeding through speed calibration. The stable negative pressure generated by the Venturi tube enables contactless ejector feeding. The gap between the discharge port and the feed inlet pipe blocks the backflow of positive pressure airflow, preventing airflow interference with the continuity of the feed flow from the screw and ensuring stable feed metering. 3. The conical contraction structure at the Venturi tube inlet significantly increases the airflow velocity at the throat, enhancing the ejector negative pressure capacity and resulting in more thorough air-feed mixing. This effectively improves feed conveying efficiency and maximum conveying distance, making it more suitable for the long-distance, high-flow feeding needs of large-scale aquaculture workshops. 4. The entire system has no complex moving airlock components, resulting in a low failure rate and low maintenance costs; it can be directly connected to existing positive pressure pneumatic feeding systems, making installation and modification convenient and highly adaptable. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a conventional venturi tube.

[0016] Figure 2 This is a schematic diagram of the structure of the present invention.

[0017] Figure 3 This is a schematic diagram of the feed pipe structure of an atmospheric ejector.

[0018] Figure 4 This is a cross-sectional view of the feed pipe of an atmospheric ejector.

[0019] Figure 5 This is a CFD simulation comparison of the feed pipe of an atmospheric ejector and a conventional venturi tube. The top left, top right, bottom left, and bottom right are the simulation results at empty pipe wind speeds of 30, 40, 50, and 60 m / s, respectively.

[0020] Figure 6 These are the stable filling coefficients of feeds #0, #2, #4, and #6 at different screw pitches and rotation speeds.

[0021] Figure 7 These are the coefficients of variation for feed grades 0#, 2#, 4#, and 6# at different screw pitches and rotational speeds.

[0022] Figure 8 The stable production rates of feed grades 0#, 2#, 4#, and 6# at different screw pitches and rotation speeds are measured. Detailed Implementation

[0023] like Figure 2As shown in Figure 4, a spiral-ejector bait conveying device mainly consists of an ejector mechanism and a horizontally arranged spiral feeder 1. The spiral feeder has an upward-opening feed port at the feed end and a downward-opening discharge port at the discharge end.

[0024] The ejector mechanism includes a blower 2 and a feeding manifold 3. The front end of the feeding manifold 3 is connected to the air outlet of the blower 2. The feeding manifold 3 includes two feeding pipes arranged coaxially, a front and a rear, and a venturi tube 4 is connected in series between the two feeding pipes.

[0025] The inlet end of the Venturi tube 4 is internally sealed with a conical spray pipe 9 that is large at the front end and small at the rear end. The Venturi tube 4 is laterally connected to the bait inlet pipe 5 before its contraction section 41. The bait inlet pipe 5 is perpendicular to the Venturi tube 4 or is set at an acute angle with the front end section of the Venturi tube 4. The upper inlet of the bait inlet pipe 5 is directly opposite the outlet of the screw feeder 1, and there is a gap between the two.

[0026] Specifically, the feed inlet pipe 5 and the front end section of the venturi pipe 4 are set at a 60° angle. 60° is an acute angle tilted forward along the airflow direction, creating a small, forward-facing angle between the feed direction and the mainstream high-speed airflow direction. This avoids the strong shearing effect of a direct, hard impact between the material and the airflow during vertical feeding. Simultaneously, the feed can smoothly flow into the mainstream along the inclined pipe wall, significantly reducing the impact and rebound of particles against pipe corners and walls. This angle significantly weakens the impact load on the feed, effectively reducing the particle breakage rate.

[0027] The conical jet tube 9 extends from the inlet end of the Venturi tube 4 to the inlet end face of the constriction section 41. Specifically, the conical jet tube 9 is 100 mm long and has a rear end diameter of 20 mm. The constriction section 41 of the Venturi tube 4 is 45 mm long, the throat 42 has a diameter of 40 mm, the length-to-diameter ratio of the throat 42 is 1, and the diffuser section 43 is 60 mm long. The inner diameter of both the inlet and outlet ends of the Venturi tube 4 is 72 mm.

[0028] A feed hopper 6 is connected to the feed inlet of the screw feeder 1, and a feed funnel 7 is connected to the feed inlet of the feed inlet pipe 5. The feed hopper 6 facilitates manual feeding or replenishment by automatic feeding equipment. The upper port diameter of the feed funnel is greater than or equal to the discharge port diameter of the screw feeder 1, which can effectively receive the feed falling from the discharge port, prevent the feed from splashing outside the feed inlet pipe 5, and reduce feed loss.

[0029] The feed pipe has a circular cross-section, while the bait inlet pipe 5 has a square cross-section. The square cross-section of the bait inlet pipe 5 guides the bait to form a uniform planar curtain of material before entering the circular air-material mixing chamber, resulting in more even dispersion of the material across the cross-section of the circular main channel. This avoids the material aggregation problem that often occurs with circular feed pipes, where material tends to concentrate in the center of the pipe. The bait also has more thorough contact with the high-speed airflow, leading to more uniform air-material mixing. The circular feed pipe is a standard, universally applicable pipe, and its coaxial connection and sealing assembly with the Venturi tube is a mature process.

[0030] The bottom end of the feeding funnel 7 is connected to a square connecting pipe 8, which is sleeved on the outside of the feeding end of the bait inlet pipe 5, thereby realizing the connection between the feeding funnel 7 and the bait inlet pipe 5. The result is simple and easy to assemble.

[0031] I. Experiment and Result Analysis of the Coupled Effect of Screw Feeder Pitch-Speed ​​Rotation-Particle Size

[0032] To address the "overhead-sliding-pulsating" conveying characteristics of large-diameter extruded materials using a screw feeder, the design included a screw feeder with blade outer diameter D=130mm, screw pitch S=43.6, 65.4, and 87.2mm (corresponding to 0.34D, 0.50D, and 0.67D respectively), shaft diameter d=13.08, 19.62, and 26.16mm, rotational speeds of 40, 60, and 80 r / min, and feed grades 0#, 2#, 4#, and 6# (corresponding to particle sizes of 1.6, 3.4, 7.1, and 10.9mm respectively). Using actual feed rate, filling coefficient, and coefficient of variation as evaluation indicators, each operating condition was repeated 10 times. Range / variance analysis was used to identify: ① the main effects and interaction effects of screw pitch and rotational speed; ② the stable operating window allowed by the combined factors of "accuracy, filling, and non-clogging," thus providing controllable feeding boundary conditions for subsequent integration with pneumatic conveying.

[0033] The experiment used sea bass feed, and the basic parameters were measured as shown in Table 1.

[0034] Table 1 Basic parameters of sea bass feed

[0035]

[0036] A fixed mass of feed is weighed and added to the feed hopper 6. The motor is started after the set speed is achieved. The feed enters the conveying space formed by the screw and cylinder through the feed inlet of feed hopper 6, and after being conveyed to the discharge outlet, it naturally falls into the feed funnel 7 below. The motor stops running after all the feed has been transferred. During operation, a stopwatch is used to record the motor running time. As the feed falls into the feed funnel 7, a receiving tray is used to catch the feed in the middle 3-pitch or 2-pitch stable section. An electronic balance is used to weigh the feed in the stable section to calculate the feeding efficiency and filling coefficient, facilitating the evaluation of feeding stability.

[0037] To systematically study the metering performance of the screw conveyor mechanism, a three-factor, multi-level comprehensive experimental method was adopted. Using the screw conveyor as the core platform, different parameter combinations were tested by changing the screw and adjusting the motor speed. Each parameter combination was repeated 10 times to eliminate random errors, resulting in 360 sets of valid data.

[0038] (1) Stable productivity Q

[0039] The stable feed conveying capacity of the screw feeder 1 is determined by selecting the feed output mass at the midpoint of the screw pitch when the system reaches a stable state. Combined with the rotational speed of the experimental group, the feed output mass per unit time during stable operation is calculated, which is the stable productivity. The stable productivity directly evaluates the feeding efficiency of the equipment, and the calculation method is as follows:

[0040]

[0041] Where: Q—stable productivity (t / h);

[0042] m — Select the output feed mass (g) under steady-state conditions;

[0043] n——rotation speed (r / min);

[0044] k — Select the output feed pitch number.

[0045] (2) Stable filling coefficient ψ

[0046] The "stable filling coefficient" (ψ) is used to evaluate the material flowability during stable system operation. It is the ratio of the actual area occupied by the material on the cross-section perpendicular to the spiral axis to the effective cross-sectional area of ​​the spiral groove. A low ψ indicates that the material is "thin-layered sliding / underfilled" within the groove, resulting in bridging and collapse, high axial propulsion efficiency, and unstable output per unit angle. A high ψ indicates that the material is continuously compressed closer to the cylinder, increasing frictional resistance and local compaction, inducing blockage and structural damage to particles. The "stable filling coefficient" used in this paper refers to the ψ level and its fluctuation range when the system enters the steady-state feeding stage. It has the following relationship with the conveying capacity, and the ψ value can be calculated using the following formula.

[0047]

[0048] Where: Q—stable productivity (t / h);

[0049] D—Helical blade diameter (m);

[0050] S—Pitch (m);

[0051] n——rotation speed (r / min);

[0052] ψ—Stability fill factor;

[0053] λ — Feed bulk density (g / cm3);

[0054] ε— Inclined conveying coefficient, taken as 1 for horizontal arrangement.

[0055] (3) Coefficient of variation (CV)

[0056] The stability of the measurement is determined by the ratio of the standard deviation to the mean of the feed quality in 10 repeated experiments.

[0057] Analysis of the influence of pitch on fill factor ψ and metering stability (CV):

[0058] The screw pitch is a key geometric parameter that determines the volume of the spiral groove and the feeding speed. Analysis of feeds of various diameters shows that the screw pitch has a significant impact on the filling factor ψ and metering stability (CV).

[0059] Effect on the fill factor ψ: Figure 6 These are the stable filling coefficients of feeds #0, #2, #4, and #6 at different screw pitches and rotation speeds, such as... Figure 6 As shown, the filling coefficient is significantly lower with small pitch screws. Within the speed range of 40-80 r / min, the ψ value ranges from 0.35 to 0.42, with some conditions approaching 0.45. Feeds #0, #2, and #4, during small pitch conveying, do not undergo axial settling and compaction, resulting in thin-layer slippage; material #6, due to its larger particle size, creates a "gap" at the inlet. Neither material can establish a stable, dense filling structure, hence the lower filling coefficient under small pitch conditions. The ψ values ​​for medium and large pitch screws are stable in the ranges of 0.55-0.65 and 0.57-0.60, respectively, indicating a better match between the tank space and material flow rate.

[0060] Impact on metrological stability (CV): Figure 7 These are the coefficients of variation for feed grades 0#, 2#, 4#, and 6# at different screw pitches and rotational speeds, such as... Figure 7 As shown, the CV value is strongly correlated with the screw pitch and rotational speed. Analysis reveals that the screw pitch affects metering stability by influencing filling uniformity. Under small screw pitch conditions, the friction between the feed and the cylinder wall is stronger for #0 feed at low rotational speeds, causing system vibration and resulting in pulse-like fluctuations in the feed flow, with a large CV value fluctuation range (0.78%–1.10%). Large screw pitch results in insufficient filling at low rotational speeds, leading to discontinuous material flow, and its CV value is greater than that of medium screw pitch under most operating conditions. Medium screw pitch exhibits lower CV values ​​and smaller fluctuations under all operating conditions, demonstrating its ability to form a stable and continuous feed flow.

[0061] Analysis of the interaction between rotational speed and productivity and stability:

[0062] Rotation speed is a direct operational variable for adjusting feeding capacity. It has a significant interaction with screw pitch, and together they determine productivity Q and stability.

[0063] Main effects on productivity Q: Figure 8 The stable production rates of feed grades 0#, 2#, 4#, and 6# at different screw pitches and rotation speeds are as follows: Figure 8 As shown, for any fixed pitch, the stable productivity Q increases approximately linearly with increasing rotational speed n, conforming to the theoretical relationship Q∝n. At the same rotational speed, a larger pitch screw has a larger conveying volume per revolution, and its Q value is usually the highest.

[0064] The impact of pitch interaction on stability: Matching the rotational speed and pitch is crucial. With a small pitch, increasing the rotational speed can alleviate CV fluctuations to some extent by reducing the contact time between the feed and the cylinder wall, but it remains at a relatively high level. Increasing the rotational speed with a large pitch will worsen the problem of insufficient filling, causing a significant increase in the CV value. When the rotational speed of a medium pitch increases from 40 r / min to 60 r / min, productivity improves significantly, and the CV value fluctuates less, remaining at a low level. Within this parameter window, increasing the rotational speed increases the flow rate without disrupting the stable material conveying state. When the rotational speed of a medium pitch increases to 80 r / min, Q continues to increase, and the CV value slightly rebounds; excessively high rotational speeds exacerbate material sliding and scattering within the trough.

[0065] Particle size effect analysis:

[0066] Feed particle size directly affects the flow characteristics between particles and the packing behavior of the spiral. Comparison of experimental data from different feed types ( Figure 6 , 7 8) Discovery:

[0067] Particle size has a general impact on packing density and flowability. For feeds #2, #4, and #6, as the particle size increases, the bulk density decreases, the flowability between particles deteriorates, the CV value increases, and the packing coefficient decreases.

[0068] Large-diameter feed particles exhibited a "gap" phenomenon under low-to-medium screw pitch conditions. Experiments with feed #6 at medium-to-low screw speeds showed this "gap" phenomenon, leading to insufficient and uneven filling. Data showed a lower ψ value and a higher CV value under this condition compared to medium screw pitch conditions. This phenomenon validates the design principle that "screw pitch and particle size must be matched."

[0069] Considering factors such as filling coefficient, metering stability, productivity, and adaptability to large-particle-size materials, the optimal parameters for the screw conveyor in the subsequent joint commissioning experiment of the pneumatic conveying system are determined as follows:

[0070] Optimal pitch: 65.4 mm (S / D≈0.503). This pitch effectively avoids problems such as feed slippage, insufficient filling, and empty space, providing the best tank space for No. 6 feed.

[0071] Optimal rotational speed: 60 r / min. At this speed, the system has high productivity, good metering stability (CV<1%), stable filling coefficient ψ, and can form a stable feed plug flow.

[0072] This parameter combination enables high-precision and stable material feeding while maintaining high productivity. It provides clear boundary conditions for the pneumatic matching design of the ejector structure and pneumatic conveying system, and is a key prerequisite for realizing the integration of "mechanical precision feeding + pneumatic high-efficiency and low-loss conveying".

[0073] II. Comparison of CFD simulations of ejector mechanisms.

[0074] Figure 1 This is a schematic diagram of a conventional venturi tube, such as... Figure 1 As shown, the conventional venturi tube does not have a conical spray nozzle added to the inlet end, and the bait inlet pipe is vertically connected to its throat. For example... Figure 2 As shown in Figure 4, the ejector mechanism of this invention is an atmospheric ejector, wherein the Venturi tube 4 and the bait inlet tube 5 are combined to form the feed pipe of the atmospheric ejector.

[0075] 3D models of the atmospheric ejector feed pipe and a conventional venturi tube were created using SolidWorks and imported into Fluent for simulation calculations. The negative pressure and wind speed at the feed pipe were compared under empty pipe wind speeds of 30, 40, 50, and 60 m / s. The simulation results are as follows: Figure 3 As shown in the figure. The results show that the static pressure at the feed pipe of the atmospheric ejector is lower than that of the conventional venturi tube. The suction velocity of the conventional venturi tube tends to be 0 and there is some disturbance, while the suction velocity of the feed pipe of the atmospheric ejector is larger.

[0076] Backflow prevention performance verification:

[0077] 1. Operating conditions

[0078] Under the optimal spiral feeder conditions (65.4 mm, 60 r / min), both the atmospheric ejector and the conventional venturi tube were installed. The blower was run at the target wind speed (approximately 45–50 m / s). The wind speed in the empty pipe at the feeder inlet was measured using an anemometer and compared with the CFD simulation results for verification. Then, the spiral feeder 1 was connected and run. The occurrence of material accumulation, poor conveying, and gas backflow was observed and recorded.

[0079] 2. Comparison Results

[0080] Under the target wind speed condition, the empty tube velocity of a conventional venturi tube approaches 0, and the static pressure difference with atmospheric pressure is small. With further increasing the wind speed, at the extreme wind speed of 63 m / s, the intake wind speed is 1.5 m / s. After connecting to screw feeder 1, material accumulation occurs in the hopper collection area, eventually leading to complete jamming. The atmospheric ejector, under the target wind speed condition, generates an intake empty tube velocity of 20 m / s. After connecting to screw feeder 1, the conveying is smooth, and no material accumulation or conveying obstruction occurs. The verification results are consistent with the simulation data; therefore, the atmospheric ejector structure is determined to be suitable for this system's operating conditions.

[0081] System integration and continuous operation capability:

[0082] Under the conditions of positive pressure air velocity of 40m / s, spiral pitch of 65.4mm, and spiral speed of 60r / min, the system can run continuously without intervention for more than 5 minutes, with no gas backflow in the spiral cylinder, uniform material discharge, and stable operation.

[0083] III. Threshold test for breakage rate of positive pressure air conveyor.

[0084] Positive pressure pneumatic conveying is typically used for long-distance transport, where the actual initial wind speed is relatively high. This paper designs single-factor and combined experiments for feed #6, with horizontal air velocity V = 50, 55, and 60 m / s in the empty pipe, and the number of bends T = 1, 2, and 3 (90° bends, fixed bend diameter ratio / installation position). The breakage judgment process involves removing and weighing all material from the feed collection box after each pneumatic conveying cycle. First, broken particles are removed using a 10 mm standard fine-mesh sieve. Then, manual selection is performed from the sieve, using "missing projected area ≥ 1 / 5 or obvious structural defects" as the joint criterion for manual screening of macroscopically broken particles. Particles of this type are then picked out, and the particles picked out in both cycles are combined and weighed. The breakage amount is defined as the difference in mass before and after conveying plus the mass of the broken material picked out. The breakage rate is calculated based on this.

[0085] Through experiments, the abrupt change trend of breakage rate with wind speed and number of bends is given, the safe operating range with low loss is delineated, and the threshold wind speed is found.

[0086] During the feed feeding and conveying process, mechanical extrusion and collision can cause some feed particles to be damaged, such as chipped, broken, or worn. Damaged material appears as irregular particles or powder, which, upon entering the fishpond, increases ammonia nitrogen levels and pollutes the water. Therefore, this experiment clarifies that the criterion for judging broken material is a missing area ≥ 1 / 5 or obvious gaps and powder. The breakage rate B is the ratio of the broken amount to the mass before conveying, calculated using the following formula:

[0087]

[0088] In the formula: B — breakage rate (%);

[0089] M1 — Weight before conveying (g);

[0090] M2 — Weight (g) after conveying and passing through a 10mm fine mesh sieve;

[0091] M3 — Mass of crushed material (g).

Claims

1. A spiral-ejector bait conveying device, comprising a horizontally arranged spiral feeder (1), wherein the spiral feeder has an upward-opening feed port at its inlet end and a downward-opening discharge port at its outlet end; characterized in that: It also includes an ejector mechanism, which includes a blower (2) and a feeding manifold (3). The front end of the feeding manifold (3) is connected to the air outlet of the blower (2). The feeding manifold (3) includes two feeding pipes arranged coaxially, a front and a rear, and a venturi tube (4) is connected in series between the two feeding pipes. The inlet end of the venturi tube (4) is sealed with a conical spray pipe (9) with a large front end and a small rear end. The venturi tube (4) is laterally connected to a bait inlet pipe (5) before its contraction section (41). The bait inlet pipe (5) is perpendicular to the venturi tube (4) or is set at an acute angle with the front end of the venturi tube (4). The upper inlet of the bait inlet pipe (5) is directly opposite the outlet of the screw feeder (1), and there is a gap between them.

2. The spiral-ejector bait conveying device according to claim 1, characterized in that: The conical jet tube extends from the inlet end of the venturi tube (4) to the inlet end face of the contraction section (41).

3. The spiral-ejector bait conveying device according to claim 2, characterized in that: The conical spray pipe (9) has a length of 100 mm and a rear port diameter of 20 mm.

4. The spiral-ejector bait conveying device according to claim 2, characterized in that: The Venturi tube (4) has a contraction section (41) with a length of 45 mm, a throat (42) with a diameter of 40 mm, a length-to-diameter ratio of 1, and a diffusion section (43) with a length of 60 mm.

5. The spiral-ejector bait conveying device according to claim 2, characterized in that: The inner diameter of both the inlet and outlet ends of the Venturi tube (4) is 72 mm.

6. The spiral-ejector bait conveying device according to claim 1, characterized in that: The feed hopper (6) is connected to the feed inlet of the screw feeder (1), and the feed funnel (7) is connected to the feed inlet of the feed pipe (5).

7. The spiral-ejector bait conveying device according to claim 6, characterized in that: The feeding pipe is a circular cross-section pipe, and the bait inlet pipe (5) is a square cross-section pipe.

8. The spiral-ejector bait conveying device according to claim 7, characterized in that: The bottom end of the feeding funnel (7) is connected to a square connecting pipe (8), which is sleeved on the outside of the feeding end of the bait inlet pipe (5), thereby realizing the connection between the feeding funnel (7) and the bait inlet pipe (5).

9. The spiral-ejector bait conveying device according to claim 1, characterized in that: The bait inlet pipe (5) and the front end section of the venturi pipe (4) are set at a 60° angle.

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