A feed hopper

Abstract

The utility model provides a kind of feeding hopper, it is related to solid-liquid separation and material conveying equipment technical field.The feeding hopper includes feed bin, be set in feed bin and be driven by helical blade of screw shaft, it is equipped with front end plate between screw shaft and feed bin, front end plate is equipped with the through -hole for screw shaft to wear, it is equipped with sealing cover between front end plate and feed bin;Feed bin is equipped with feed bottom plate, its inner edge is matched with the outer diameter of helical blade and forms radial clearance;Scraping knife for removing material in front end area is equipped on helical blade;Front end plate is equipped with flow transition piece towards helical blade side, its inner surface is matched with the rotation envelope line of helical blade;The feeding end of screw shaft is coaxially equipped with scraping ring, and the outer edge between scraping ring and flow transition piece inner surface forms sweeping gap.The utility model structure is compact, sealing is reliable, can effectively eliminate front end dead angle, reduce material wall hanging and bridging, improve continuous feeding stability and operating reliability.

Description

Technical Field

[0001] This utility model relates to the technical field of solid-liquid separation and material conveying equipment, specifically to a spiral feed hopper for the feed end of a spiral press (or spiral conveying-pressing integrated equipment). Background Technology

[0002] A screw press is a continuously operating horizontal single-shaft solid-liquid separation device that uses extrusion pressure to dehydrate materials. Its main working process includes: material enters the rotating drum from the feed hopper and is propelled into the drum body by the screw. Due to the screw pitch and the design of the conical section, the volume of the material decreases, and the counter-pressure device at the end of the equipment provides a reverse force. These factors result in a significant pressing effect, causing the liquid phase to separate from the material and be discharged through the filter holes on the rotating drum, while the solid phase is discharged from the slag outlet.

[0003] Currently, in screw presses, material is pushed into the drum by the screw blades when it enters the feed hopper. However, due to the existing feeding structure, there are dead zones at the front plate that the screw blades cannot reach, causing localized material retention and adhesion to the walls, affecting continuous feeding and hygiene. At the same time, the radial distance between the feed bottom plate and the screw blades is set too large, which easily leads to material accumulation and bridging in this gap area, resulting in poor feeding, increased torque / current fluctuations, and increased maintenance and cleaning frequency.

[0004] In addition to the typical problems mentioned above, the feed geometry of existing equipment often does not fully connect with the rotating envelope of the helical blades, and the sealing structure of the shaft perforation and the front end area is not reliable enough, which easily leads to leakage and secondary pollution; easily worn and eroded parts lack modular wear-resistant protection, resulting in high maintenance costs; critical gaps are mostly fixed or without scale adjustment, making it difficult to quickly reproduce and optimize for incoming materials with different particle sizes, solid contents and rheological properties.

[0005] Therefore, the industry urgently needs to improve the structure of the feed end of the screw press: while ensuring the shaft perforation seal and front-end geometric continuity, eliminate dead corners at the front end, reasonably limit and adjust the key radial clearance between the feed bottom plate and the screw blades, and strengthen the active removal and anti-bridging capabilities of accumulated material in the front-end area, thereby improving the stability of continuous feeding, reducing energy consumption and maintenance costs, and extending the service life of the whole machine. Utility Model Content

[0006] The main objective of this invention is to provide a feed hopper with stable continuous feeding and reliable operation.

[0007] A feeding hopper includes a feeding bin, a spiral blade disposed within the feeding bin and driven by a spiral shaft, a front end plate disposed between the spiral shaft and the feeding bin, the front end plate having a through hole for the spiral shaft to pass through, the diameter of the through hole matching the diameter of the spiral shaft; a sealing cover plate disposed between the front end plate and the feeding bin; a feeding bottom plate disposed within the feeding bin, the inner edge of the feeding bottom plate matching the outer diameter of the spiral blade, and forming a radial gap between the bottom plate and the outer edge of the spiral blade for material passage; a scraper disposed on the spiral blade for sweeping away accumulated material in the front end area; a flow guide transition member disposed on the side of the front end plate facing the spiral blade, the inner surface of the flow guide transition member matching the rotation envelope of the spiral blade; a scraper ring coaxially disposed at the feed end of the spiral shaft, the outer edge of the scraper ring forming a scraping gap with the inner surface of the flow guide transition member.

[0008] Technical principle: The flow guide transition component eliminates the low-speed stagnant zone near the front end plate through geometric continuity with the rotating envelope surface of the spiral blade, reducing backflow and material buildup; the scraper ring provides "near-wall shearing" along the circumferential direction, continuously sweeping away the material adhering to the front end / flow guide surface; the critical radial clearance (bottom plate - blade) determines the filling coefficient, shear strength and compaction initiation conditions at the feed end, and the adjustable structure allows this clearance to adapt to materials with different particle sizes / solid contents, suppressing bridging and material buildup.

[0009] Technical implementation process: The flow guide transition component is CNC machined with a conical / arc surface. The inner contour is fitted according to the blade pitch and outer diameter, and the assembly reference surface and positioning pin hole are reserved. The scraper ring and the spiral shaft are positioned by key / expansion sleeve, and the end face runout is ≤0.05mm. After assembly, the scraping gap is checked with a feeler gauge. The adjustable base plate is finely adjusted through an arc-shaped long hole and locking mechanism. After assembly, the radial gap is set within the preset range (e.g., 1-2 mm) according to the process material. After completion, a joint verification of no-load and loading is carried out, and the current fluctuation and torque pulsation index are recorded.

[0010] Technical effects / advantages: Eliminates "dead corners" at the front end, reducing material buildup and accumulation; improves feeding uniformity and reduces torque / current fluctuations; quickly replicates the optimal gap for different materials, reducing downtime for cleaning and the risk of jamming, and improving the stability of continuous operation.

[0011] Furthermore, the material scraping gap between the outer edge of the scraper ring and the inner surface of the guide transition piece is limited to 0.1–1.0 mm.

[0012] Technical principle: If the gap between the sweeping particles is too large, the near-wall shearing will be insufficient and the cleaning will be incomplete; if it is too small, wear will easily occur and hard inclusions will be trapped. By controlling the gap within a small-scale non-contact area, effective boundary layer shearing and "near-wall re-transport" can be provided without interference.

[0013] Technical implementation process: fine-tune the axial / radial position by replacing the scraper ring positioning shim or expansion sleeve; cold / hot state compensation: set a safety margin of -0.05 to -0.1 mm in the cold state based on the material expansion coefficient; use feeler gauge to measure the entire circumference and blue oil inspection to ensure the consistency of the clearance throughout the circumference (circular runout is controllable).

[0014] Technical effects / advantages: It forms a stable and sufficient "non-contact material sweeping", significantly reduces front-end material hanging and micro-agglomeration, reduces abnormal wear and the probability of jamming, and extends the maintenance cycle.

[0015] Furthermore, the feed base plate is adjustablely connected to the feed bin via an arc-shaped elongated hole and a locking mechanism, so that the radial gap between the feed base plate and the outer edge of the spiral blade is adjustable within the range of 0.5 to 3.0 mm, and a scale indicator is provided to indicate the radial gap.

[0016] Technical principle: Radial clearance determines the initial shear / compression strength and the probability of material passage; when the clearance is on the same order of magnitude as the material's characteristic size, bridging or a "leakage-collapse" cycle is most likely to occur. The adjustable structure transforms this key parameter from a "fixed compromise" to "material-dependent optimization".

[0017] Technical implementation process: The arc-shaped elongated hole is designed according to the outer circle trajectory of the blade, and is used in conjunction with the dovetail / eccentric cam / scale pressure plate to achieve one-handed quick locking; multiple process positions are set: 0.5 / 1.0 / 1.5 / 2.0 / 3.0 mm, which facilitates quick switching; after adjustment, the vibration and current curves are verified in three sections: no load, low load and rated load.

[0018] Technical effects / advantages: Adaptable to different materials such as powder, fiber, and oily residue, reducing bridging and "mouse hole" phenomena; improves the consistency of filling and pre-compaction without increasing energy consumption, reducing downtime due to malfunctions.

[0019] Furthermore, the flow guide transition component has a conical or arc-shaped structure with an inlet cone angle of 20° to 45° and an inner surface roughness Ra ≤ 1.6 μm.

[0020] Technical principle: A suitable cone angle / curvature can smoothly convert the upstream axial momentum into a tangential component in the same direction as the blade, reducing diffusion and separation, and minimizing backflow vortices and stagnation zones; if the cone angle is too small, the drag will be large, and if it is too large, the rectification will be insufficient.

[0021] Technical implementation process: Based on the blade pitch p and outer diameter D, the minimum clearance envelope is fitted using CAD to determine the cone angle or spline surface; the surface roughness Ra≤1.6μm, and an anti-sticking layer (such as PTFE spraying) can be optionally applied; quick-release clamps + positioning pins are used for connection, and different cone angle parts can be replaced within 5 minutes for comparative tests.

[0022] Technical effects / advantages: Forms a continuous material guiding channel, reducing front-end pressure head loss and eddies; more stable feeding, reduced noise and vibration, and improved filling coefficient at the feed end.

[0023] Furthermore, the scraper is arranged on the feed side edge of the spiral blade and forms an angle of 10° to 45° with the leading edge of the spiral blade. The scraper is a replaceable blade structure or an elastic follower structure.

[0024] Technical principle: The end-point "near-end scraping + guiding" effect promptly peels off the adhesive layer and guides the near-wall material into the meshing area, improving the uniformity of material receiving in the first ring.

[0025] Technical implementation process: the tool holder is screwed / riveted; the cutting edge is selected from wear-resistant alloy or UHMW-PE; the elastic follow-up is buffered by spring / rubber pad; and limit is set to avoid hard interference.

[0026] Technical benefits / advantages: Reduced buildup at the front end, lower peak torque; quick blade change, low maintenance costs.

[0027] Furthermore, the sealing cover is an annular cover and is sealed to the feed hopper by a quick-opening clamp and an O-ring; the sealing cover and the front end plate are provided with a positioning pin or a stop to ensure assembly coaxiality and sealing pressure.

[0028] Technical principle: Geometric positioning ensures coaxiality and stable sealing pressure; elastic sealing absorbs assembly and thermal expansion errors, suppressing leakage.

[0029] Technical implementation process: Three-prong clamp + food-grade / oil-resistant O-ring (grooved according to ISO 3601, compression rate 20%~25%); anti-loosening safety and accidental opening interlock are set.

[0030] Technical benefits / advantages: reliable sealing, rapid opening and closing; short maintenance time, and improved hygiene and safety levels.

[0031] Furthermore, a guide throat is provided between the feed bin and the feed area of ​​the spiral blade. The inner diameter of the guide throat gradually narrows along the material flow direction, with a diameter reduction ratio of 1.1 to 1.5. The inner wall is provided with guide ribs in the same direction as the spiral blade. The pitch of the guide ribs is 0.6 to 1.0 times the pitch of the spiral blade.

[0032] Technical principle: If the diameter ratio is too small, the rectification will be insufficient; if it is too large, the pressure head loss and the risk of blockage will increase. The guide rib pitch and the blade pitch form a "phase match", establishing a near-synchronous spiral path before the material enters the blade, reducing relative slip and energy loss.

[0033] Technical implementation process: Select the reduction ratio based on the target throughput and material rheological parameters, and verify the pressure drop using finite element or simplified flow calculations; configure the rib spacing as 0.6p to 1.0p and the rib height as 1 to 3mm (example) according to the blade pitch p, and conduct sample comparison; use the mean square fluctuation of current and the number of blockages as operating condition evaluation indicators on site to determine the final parameters.

[0034] Technical effects / advantages: Achieve a balance between "moderate pre-compaction and low pressure drop", reduce torque pulsation and energy consumption, and increase the stable processing capacity per unit time.

[0035] Furthermore, an arch-breaking component is installed on the feed hopper. The arch-breaking component is one of mechanical vibration type, eccentric pendulum type or airbag pulsation type, and is linked to the start / stop of the host or the current fluctuation threshold for control.

[0036] Technical principle: Kinetic energy is periodically injected into the hopper wall to break the self-supporting arch bridges caused by static friction and cohesion of the particles, so that the material can resume mass flow.

[0037] Technical implementation process: Mechanical vibration is set with elastic hammer head and boss; eccentric pendulum sweeps frequency at 5-25 Hz; airbag is pulsed inflated and deflated at 0.4-0.6 MPa; threshold linkage is performed with PLC.

[0038] Technical effects / advantages: Significantly reduces manual knocking and downtime for arch clearing, adapts to long fiber / high viscosity conditions, and improves stability and availability.

[0039] Furthermore, the material contact surfaces of the flow guide transition component, the feed base plate, and / or the feed throat are provided with replaceable wear-resistant liners. The wear-resistant liners are made of polymer wear-resistant plates or welded wear-resistant steel plates, and are fixed by dovetail groove limiting and countersunk screws.

[0040] Technical principle: The abrasive load is transferred to an independent liner to maintain the geometric accuracy of the substrate; low surface energy materials help reduce viscosity.

[0041] Technical implementation process: lining plates are arranged in zones; end chamfering prevents material from getting stuck; rapid local replacement is performed according to wear marking criteria.

[0042] Technical benefits / advantages: quick maintenance and short downtime; maintains smooth flow channels over the long term, reduces energy consumption and material buildup, and lowers total lifespan costs.

[0043] Furthermore, the feed hopper is provided with an observation and cleaning port, which is connected to the sealing assembly with a quick-opening structure and is equipped with a safety interlock mechanism to prevent accidental opening.

[0044] Technical principle: While maintaining the sealing pressure, it provides a visible and in-situ cleaning channel, and interlocks to avoid the risk of opening under pressure / rotation.

[0045] Technical implementation process: Transparent viewing window (tempered glass or PC) + three-prong clamp; O-ring seal; equipped with mechanical / electrical double interlock and vent; protective netting covering the viewing window.

[0046] Technical effects / advantages: Inspections are more intuitive, troubleshooting and CIP are more efficient; safety is improved and downtime due to malfunctions is reduced. Attached Figure Description

[0047] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model application; Detailed Implementation The following detailed description illustrates the specific implementation method: Example 1 like Figure 1 As shown, a rotating drum is fixedly connected to the front end of the shell, and a front end plate 3 is provided on the feed side of the rotating drum. A front flow guide transition component is installed between the front end plate 3 and the feed end of the spiral blade. The flow guide transition component is an integral part with a conical surface and rounded corner transition, with a cone angle of 30° and an inner surface Ra≤1.6 μm. A scraper ring is coaxially fitted at the feed end of the spiral shaft, and a scraping gap of 0.20±0.05 is provided between the outer circle of the scraper ring and the inner surface of the flow guide transition component. An arc-shaped adjustable feed base plate 1 is installed at the bottom of the feed hopper. The feed base plate 1 is connected to the shell through two arc-shaped elongated holes and a locking mechanism (eccentric pressure block + M10 locking bolt), and can be continuously adjusted within the range of 0.5 to 3.0. In this embodiment, the radial gap between the feed base plate 1 and the outer edge of the spiral blade 6 is set to 1.2. A guide throat is inserted between the feed hopper and the drum. The throat has a diameter reduction ratio of 1.3, and its inner wall is equipped with guide ribs in the same direction as the spiral. The pitch of the guide ribs is 0.8 times the pitch p of the spiral blades, and the rib height is 2. An observation and cleaning port is provided on the side wall of the shell, which is sealed with a quick-opening clamp and a sealing assembly. The sealing element is an oil-resistant silicone rubber O-ring. The observation window is made of tempered glass and covered with a stainless steel protective mesh. Replaceable wear-resistant liners (UHMW-PE, 10mm thick, dovetail groove + countersunk screws) are laid on the inner surface of the guide transition component and the throat.

[0048] Examples of component materials and dimensions: Housing, drum, front end plate 3: SUS304; Spiral blade 6: outer diameter D=220, pitch p=180, thickness δ=6; Scraper ring: 40Cr quenched and tempered + surface nitriding (0.3 depth); Transition guide: SUS304 integral milling and turning; Power: 5.5 kW motor + reducer, rated speed r=28 rpm.

[0049] Assembly and calibration steps: S1. Install the flow guide transition component, using a positioning pin + clamp structure, and check that the coaxiality with the front end plate 3 is ≤0.05; S2. Install the scraper ring and fix it with an expansion sleeve / key connection. Rotate the screw shaft to check the scraping gap of 0.20±0.05 around the entire circumference. Use a feeler gauge to measure once every 90° and record the circular runout data. S3. Install the arc-shaped adjustable feed base plate 1. First, loosen the eccentric pressure block and make the feed base plate 1 finely adjust along the arc-shaped long hole to the set gap 1.2, and tighten the torque 35 N·m. S4. Insert the feed throat and tighten the clamp, and confirm that the guide rib is aligned with the direction of the spiral blade 6; S5. Install the observation and cleaning port and sealing components, and conduct static water pressure and no-load tests; S6. Feed fruit pomace with a solid content of 12%, record the current curve and torque pulsation mean square value for 10 minutes. If the fluctuation is > ±7%, fine-tune the gap of the feed bottom plate 1.

[0050] Running result: After running continuously for 2 hours, there was no visible material buildup in area 3 of the front plate, and the current fluctuation was ≤±6%. After stopping the machine, the observation port was opened, and there was only a thin wet film on the surface of the flow guide transition part and the throat, with no visible agglomeration. The cleaning time was <5 minutes.

[0051] Example 2 like Figure 1 As shown, based on Example 1, symmetrical arch-breaking components are installed on both sides of the feed hopper, using an eccentric pendulum type: a small-power motor (60 W) drives the eccentric block, with an adjustable working frequency of 12-18 Hz, and rubber vibration isolation seats are used to connect it to the hopper wall. The eccentric block has a mass of 50 g and an eccentricity of 8 mm. A speed adjustment knob and start / stop indicator light are set on the outside of the housing. The arch-breaking control is interlocked with the main unit: when the main unit is running, it automatically executes in a pulse mode of "10 s working / 20 s rest"; when the current fluctuation exceeds the preset threshold ±10%, it is temporarily increased to 18 Hz and works continuously for 30 s.

[0052] Parameter adjustment: Adjust the gap between the feed base plate 1 and the spiral blade 6 to 0.8 to improve the shearing at the feed end; The inner surface of the flow guide transition component is coated with an anti-stick layer (PTFE) with a thickness of approximately 30 μm. The scraper ring gap is set to 0.25 to enhance near-wall shearing.

[0053] Effect evaluation: The mixture of vegetable residue and pulp containing long fibers (mass ratio 7:3) was processed for 4 consecutive hours without "mouse holes" or self-locking bridging. The average throughput was increased by about 12% compared to Example 1 (at the same speed), and the mean square value of torque pulsation was reduced by about 18%.

[0054] Example 3 like Figure 1 As shown, for oily / high-viscosity materials, the aforementioned eccentric rapping may cause excessive fluctuations in the material surface. Therefore, an airbag pulse-type arch-breaking component is adopted: four flat airbags (each with an effective area of ​​approximately 80×200) are arranged circumferentially on the inner wall of the feed hopper. A solenoid valve controls the pulse charging and discharging of compressed air at 0.4–0.6 MPa, with a typical cycle of “0.3 s charging – 1.2 s discharging – 3 s interval”. The gap between the feed base plate 1 and the spiral blade 6 is adjusted to 2.5, the guide throat diameter reduction ratio is 1.2, and the guide rib pitch is 0.6p. The scraper ring has a scraping gap of 0.40 to balance cleaning and oil film buffering. The sealing component is replaced with FKM material O-rings to adapt to temperatures of 60–90℃.

[0055] CIP (Cleaning In-Place) process (after shutdown): C1. Close the feed, empty the residual material, and turn on the CIP spray system; C2. Alkaline wash at 55℃ (0.8% NaOH + surfactant) for 8 minutes at 5 rpm; C3. Rinse with room temperature water for 3 minutes; C4. Pickling at 60℃ (0.3% citric acid) for 5 minutes; C5. Rinse with clean water until pH≈7, then open observation and cleaning port 12 to check for dead corners; C6. Reset the seal and jog the drain.

[0056] Effect: The feeding is stable with no obvious oil clumps remaining; the CIP post-flow guide transition component and throat surface are clean with a cumulative residue of <1 g, and the seal is intact with no leakage.

[0057] Example 4 like Figure 1 As shown, for highly abrasive working conditions such as sand-containing slurry, the flow guide transition component, the material guide throat, and the inner surface of the feed bottom plate 1 are equipped with partitioned wear-resistant liners: Straight section of throat and high-wear area at corners: wear-resistant steel plate (such as Cr series, 6mm thick, surface hardness HRC58-62) is welded on. Other areas: UHMW-PE board (thickness 8-10 mm); The liner is fixed with dovetail grooves and M6 countersunk screws, and the ends are chamfered with R2. The outer circle of the scraper ring is coated with hard alloy (WC-Co, 0.2mm thick). The guide ribs are made of HARDOX wear-resistant plates welded together, with a rib height of 2.5m.

[0058] Maintenance and replacement: The system includes wear observation holes and thickness gauge lines (in 2 mm increments). When the remaining thickness in the high-wear zone is less than 3 mm, only the liner for that zone needs to be replaced, with a single replacement taking approximately 20 minutes. This approach reduces total downtime for maintenance by about 35% compared to the non-zoned approach.

[0059] Example 5 like Figure 1 As shown, to achieve rapid process reproduction, a gap scale indicator is installed on the outside of the adjustment mechanism of the feed base plate 1: a stainless steel scale (0.25 divisions per scale) + an aluminum alloy pointer, with the scale concentric with the arc-shaped elongated hole. The following calibration procedure establishes a one-to-one correspondence between the scale and the actual gap: B1. Position the spiral blade 6 at the reference angle at the feed end (with the keyway as 0°), and use feeler gauges of 0.5 / 1.0 / 1.5 / 2.0 / 2.5 / 3.0 to measure the contact criticality one by one; B2. Record the pointer scale corresponding to each critical position and form a calibration table to be attached to the outside of housing 1; B3. Set a mechanical limit block to prevent the pointer from exceeding the two extreme positions of 0.5 and 3.0, and prevent interference.

[0060] When switching between different batches of materials, the operator only needs to rotate the calibration table to the corresponding scale to reproduce the optimal gap, reducing the material change adjustment time to less than 1 minute.

[0061] Example 6 The sealing assembly uses a three-clamp quick-opening clamp with a secondary anti-disengagement pin; the O-ring groove is designed according to ISO 3601, with a compression ratio of 20%–25%, and a 1.5 mm vent hole with mechanical interlock is provided on the inspection and cleaning port: the clamp cannot be opened when the main unit is not completely stopped. After the cleaning port flange is welded to the shell, it undergoes penetrant testing to ensure the weld is dense.

[0062] Example 7 like Figure 1 As shown, the guide transition component is machined using CNC milling and turning. The inner surface is fitted with the spiral envelope surface with minimum clearance using a forming tool and spline interpolation. After machining, it undergoes micro-polishing and degreasing. The outer diameter of the scraper ring is ground to IT6 precision, with end face runout ≤0.03. The throat guide rib is bent by forming mold and then spot-welded, followed by overall solution treatment and passivation to improve corrosion resistance. The stainless steel surfaces in contact with materials are uniformly sandblasted to a matte finish (Ra≤1.6), and areas prone to material adhesion are coated with an anti-stick layer.

[0063] Operating Condition Adaptation and Parameter Recommendations (Appendix)

[0064] The table above shows recommended values. Actual values ​​can be optimized in a closed-loop manner based on on-site conditions, taking into account factors such as current fluctuations, number of blockages, and unit energy consumption.

[0065] Key Points of Use and Maintenance Start-up and shutdown sequence: Start the main unit and run it idle first, then start the feeding; when stopping the machine, first stop the feeding, then stop the main unit after 2 minutes of no load.

[0066] Quick troubleshooting: When the current fluctuation is >±12% or the sound is abnormal, check the throat and front plate 3 area by observing the cleaning port. If necessary, briefly increase the arch breaking frequency and fine-tune the gap of the feed bottom plate 1 to ±0.2.

[0067] Routine inspection: Check the gap between the scraper ring and the guide transition part every shift (check two points randomly), and check the wear of the liner plate and the tightness of the clamps every week.

[0068] Spare parts recommendations: scraper ring ×1, UHMW-PE liner 11 (high wear zone) ×2 sets, O-rings ×2 sets, eccentric block and bearing ×1 set.

[0069] The above descriptions are merely embodiments of this utility model, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of this utility model, and these should also be considered within the scope of protection of this utility model. These modifications will not affect the effectiveness or practicality of this utility model. The specific embodiments described in the specification can be used to interpret the claims.

Claims

1. A feeding hopper, comprising a feeding bin and helical blades disposed within the feeding bin and driven by a helical shaft, characterized in that: A front end plate is provided between the spiral shaft and the feed hopper. The front end plate has a through hole for the spiral shaft to pass through, and the diameter of the through hole matches the diameter of the spiral shaft. A sealing cover is provided between the front end plate and the feed hopper; The feeding hopper is equipped with a feeding bottom plate. The inner edge of the feeding bottom plate matches the outer diameter of the spiral blade and forms a radial gap between it and the outer edge of the spiral blade for material to pass through. The spiral blades are equipped with scrapers for removing accumulated material from the front end area; The front end plate is provided with a flow guide transition member on the side facing the helical blade, and the inner surface of the flow guide transition member matches the rotation envelope of the helical blade. The feed end of the spiral shaft is coaxially provided with a scraper ring, and a scraping gap is formed between the outer edge of the scraper ring and the inner surface of the flow guide transition member.

2. The feed hopper according to claim 1, characterized in that, The material sweeping gap is 0.1 to 1.0 mm.

3. The feed hopper according to claim 2, characterized in that, The feed base plate is adjustablely connected to the feed bin via an arc-shaped elongated hole and a locking mechanism, so that the radial gap between the feed base plate and the outer edge of the spiral blade is adjustable within the range of 0.5 to 3.0 mm, and a scale indicator is provided to indicate the radial gap.

4. The feed hopper according to claim 3, characterized in that, The flow guide transition component has a conical or arc-shaped structure with an inlet cone angle of 20° to 45° and an inner surface roughness Ra ≤ 1.6 μm.

5. The feed hopper according to claim 4, characterized in that, The scraper is arranged on the feed side edge of the spiral blade and forms an angle of 10° to 45° with the leading edge of the spiral blade. The scraper has a replaceable blade structure or an elastic follower structure.

6. The feed hopper according to any one of claims 1-5, characterized in that, The sealing cover is an annular cover and is sealed to the feed hopper by a quick-opening clamp and an O-ring; the sealing cover and the front end plate are provided with a positioning pin or a stop to ensure assembly coaxiality and sealing pressure.

7. The feed hopper according to claim 6, characterized in that, A guide throat is provided between the feed hopper and the feed area of ​​the spiral blade. The inner diameter of the guide throat gradually narrows along the material flow direction, with a diameter reduction ratio of 1.1 to 1.

5. The inner wall is provided with guide ribs in the same direction as the spiral blade. The pitch of the guide ribs is 0.6 to 1.0 times the pitch of the spiral blade.

8. The feed hopper according to claim 7, characterized in that, The feeding hopper is equipped with an arch-breaking component, which is one of mechanical vibration type, eccentric pendulum type or airbag pulsation type, and is linked to the start / stop of the host or the current fluctuation threshold for control.

9. The feed hopper according to claim 8, characterized in that, The material contact surfaces of the flow guide transition component, the feed base plate, and / or the feed throat are provided with replaceable wear-resistant liners. The wear-resistant liners are made of polymer wear-resistant plates or welded wear-resistant steel plates and are fixed by dovetail groove limiting and countersunk screws.

10. The feed hopper according to claim 9, characterized in that, The feed hopper is equipped with an observation and cleaning port, which is connected to the sealing assembly with a quick-opening structure and is equipped with a safety interlock mechanism to prevent accidental opening.

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