Pressure screw feeder

Abstract

The invention belongs to the technical field of spiral conveying equipment, and provides a pressure spiral feeder. Comprising a spiral shaft tube, a spiral shaft and a driving motor, the spiral shaft is divided into a conveying section, a compression section, a material plug section and a reverse pushing section, spiral blades are arranged on the conveying section and the compression section, no spiral blade is arranged on the material plug section, reverse compression spiral blades are arranged on the reverse pushing section, the screw pitch between the spiral blades on the compression section is gradually decreased, and the screw pitch between the spiral blades on the compression section is gradually decreased. A plurality of cutting tool grooves are formed in the reverse compression spiral blade on the reverse thrust section. According to the feeder, due to the fact that the formed material plug is compact enough, tests show that the feeder can dynamically and continuously feed materials into a high-pressure cooking container from normal pressure under the high-temperature and high-pressure working conditions of 1.6 MPa saturated steam, so that biomass raw materials can be rapidly decomposed, separated, extracted, cured and the like under the high-temperature and high-pressure conditions, and the biomass raw materials can be continuously fed into the high-pressure cooking container from the normal pressure under the high-temperature and high-pressure working conditions. The method is suitable for being widely popularized and used in papermaking, cellulosic ethanol and traditional Chinese medicine industries.

Description

Technical Field

[0001] This invention belongs to the technical field of spiral conveying equipment, and specifically relates to a pressure spiral feeder. Background Technology

[0002] Screw conveyors are commonly used material conveying devices and are widely applied in various work environments.

[0003] For example, in the process of crushing, cooking, maturing, extracting, and extracting wood chips, crop straw, bark or wood chips, and Chinese herbal medicines as raw materials, the crushed raw materials need to be fed into a cooking container by a screw feeder and heated and pressurized to soften the materials. Under high temperature and high pressure, the cooking, maturing, extraction, and other process requirements are completed. At the same time, the hemicellulose that connects cellulose and lignin is degraded into xylose or xylose oligomers.

[0004] For example, in the continuous steaming process of the pulp and paper industry, pressure cooking of gramineous materials such as rice straw, wheat straw, reeds, wood chips, and bamboo chips is also required. When conveying fibrous materials from an external atmospheric pressure state to a pressurized cooking vessel, a feeder is needed to seal the pressure inside the vessel. Currently, the screw feeder commonly used in the continuous steaming process of the pulp and paper industry has the following structural characteristics and working principle: The feeder mainly consists of a drive motor, a screw shaft tube, and a screw shaft composed of three parts: a conveying section, a conical compression section, and an outlet plug section. The drive motor is connected to the screw shaft for transmission. The conveying section receives the raw material and conveys it forward to the compression section. The screw shaft in the compression section is generally conical, and the volume of the spiral cavity formed between adjacent spiral blades continuously decreases. Therefore, the material is continuously compressed as it is conveyed forward in this section. In the outlet plug section, the screw shaft is a smooth shaft without spiral blades, and the screw shaft tube is a cylindrical section. The gaseous medium pressure inside the cooking vessel acts on the material in the feed plug section, compressing and compacting it to prevent gas leakage from the feeder and subsequent backflow of material from the feeder inlet. The material in the feed plug section is continuously propelled forward by the material in the rear, thus continuously feeding material into the cooking vessel. However, this type of feeder, due to the insufficient density of the feed plug, can only withstand pressures less than 0.8 MPa and lacks a dedicated high-density feed plug section. Under high-temperature, high-pressure dynamic feeding conditions, it cannot seal off steam, easily leading to backflow. Furthermore, to fully break down the biomass raw materials and allow steam to penetrate the cell walls more quickly for rapid cooking and maturation, the pressure of cooking vessels in the industry is gradually increasing, and traditional feeders can no longer meet industry demands. Summary of the Invention

[0005] The purpose of this invention is to provide a pressure screw feeder that solves the problem of insufficient pressure resistance in the prior art while ensuring stable and continuous material conveying.

[0006] To achieve the above objectives, the present invention designs a pressure screw feeder, including a screw shaft tube, a screw shaft, and a drive motor. The screw shaft is divided into a conveying section, a compression section, a material block section, and a reverse thrust section. The conveying section and the compression section are provided with screw blades, the material block section has no screw blades, the reverse thrust section is provided with reverse compression screw blades, the pitch between the screw blades in the compression section gradually decreases, and the reverse compression screw blades in the reverse thrust section are provided with a plurality of cutting grooves.

[0007] Furthermore, the cutting groove forms an angle with the axis of the helical shaft.

[0008] Furthermore, the cutting groove has a cutting edge made of cemented carbide material.

[0009] Furthermore, the spiral shaft tube is provided with a feed inlet, which is connected to the mixing feeder.

[0010] Furthermore, the conveying section, compression section, feed plug section, and reverse thrust section are arranged in sequence.

[0011] Furthermore, the inner wall of the spiral shaft tube is provided with anti-slip strips to prevent material rotation.

[0012] Furthermore, the spiral shaft tube is provided with drainage holes at the positions corresponding to the compression section and the material plug section.

[0013] Furthermore, the plurality of cutting grooves are evenly distributed along the helical direction of the reverse compression helical blade.

[0014] The pressure screw feeder of this invention has a reverse thrust section set at the front end of the screw shaft of the feeder. The reverse compression screw blades on the reverse thrust section can squeeze the material in the opposite direction, so that the material is compressed in both directions in the material plug section to form a dense material plug seal. As the screw shaft rotates, the subsequent material is strongly pushed, and the high-density material is cut and squeezed out from the cutting groove of the reverse compression screw blade and enters the cooking container, completing the dynamic feeding process of raw materials from atmospheric pressure to high pressure container. After the biomass raw materials are cut and crushed, steam can quickly penetrate into the cell wall of the raw materials, so that they are quickly cooked, cooked and separated.

[0015] The high-temperature steam inside the cooking vessel is blocked by the dense plug of the feed plug section, thus preventing the steam from backflowing out of the feeder. The material inside the feed plug section is continuously compressed and propelled forward by the subsequent material, thereby achieving continuous feeding of material into the cooking vessel. Due to the sufficiently dense plug formed by this feeder, it has been tested that under the high temperature and high pressure conditions of 1.6MPa saturated steam, the feeder can dynamically and continuously feed material from atmospheric pressure into the high-pressure cooking vessel, enabling the biomass raw materials to undergo rapid decomposition, separation, extraction, and maturation under high temperature and high pressure conditions. This invention is suitable for widespread application in the papermaking, cellulosic ethanol, and traditional Chinese medicine industries. Attached Figure Description

[0016] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 A schematic diagram of the spiral shaft structure of the invention; Figure 3 This is a schematic diagram of the reverse segment structure of the invention. Detailed Implementation

[0017] The invention will be further described below with reference to the accompanying drawings and embodiments, and its structure and advantages will become clearer.

[0018] Example 1, see Figure 1-3 A pressure screw feeder includes a screw shaft tube 1, a screw shaft 2, and a drive motor 3. The screw shaft 2 is divided into a conveying section 2.1, a compression section 2.2, a material block section 2.3, and a reverse thrust section 2.4. The conveying section 2.1 and the compression section 2.2 are provided with screw blades 2.5. The material block section 2.3 is not provided with screw blades 2.5. The reverse thrust section 2.4 is provided with reverse compression screw blades 2.6. The pitch between the screw blades 2.5 on the compression section 2.2 gradually decreases. The reverse compression screw blades 2.6 on the reverse thrust section 2.4 are provided with a plurality of cutting grooves 2.7.

[0019] Example 2, see Figure 3 Based on Embodiment 1, the cutting groove 2.7 forms an angle with the axis of the helical shaft 2. Specifically, during manufacturing, the projection of the parallel line in the opening direction of the cutting groove 2.7 forms an angle with the projection of the axis of the helical shaft 2, preferably 30° to 60°; the parallel line in the depth direction of the cutting groove 2.7 is perpendicular to the axis of the helical shaft. The purpose of this design is to create a cutting edge 2.8 at the rear of the groove wall of the cutting groove 2.7, thereby achieving the cutting and fragmentation of the high-density material in the material block section 2.3.

[0020] Example 3, see Figure 3Based on Embodiment 1, the cutting groove 2.7 has a cutting edge 2.8, which is made of cemented carbide. The cutting edge 2.8 is located on the groove edge where the cutting groove 2.7 cuts into the material when it rotates. The cutting edge 2.8 is made of cemented carbide and is then fixed by welding.

[0021] Example 4, see Figure 1 Based on Embodiment 1, the spiral shaft tube 1 is provided with a feed inlet, which is connected to the mixing feeder 4. This allows the mixing feeder 4 to be connected to the conveying section 2.1, and the use of the mixing feeder 4 for material feeding results in more uniform material distribution and prevents material bridging.

[0022] Example 5, see Figure 1 , 2 Based on Embodiment 1, the conveying section 2.1, compression section 2.2, material plug section 2.3, and reverse thrust section 2.4 are arranged sequentially. The conveying section 2.1 conveys the material to the compression section 2.2, where the material undergoes initial compression. The reverse compression spiral blades 2.6 on the reverse thrust section 2.4 can reverse-express the material, causing the material to undergo bidirectional compression in the material plug section 2.3, resulting in a significantly higher density compared to traditional feeders.

[0023] Example 6, see Figure 1 Based on Embodiment 1, the inner wall of the spiral shaft tube 1 is provided with anti-slip strips to prevent material rotation. The anti-slip strips allow the material to move forward better and prevent slippage.

[0024] Example 7, see Figure 1 Based on Embodiment 1, drainage holes are provided on the spiral shaft tube 1 at positions corresponding to the compression section 2.2 and the material plug section 2.3. The purpose is to facilitate the drainage of moisture generated during material compression.

[0025] Example 8, see Figure 3 Based on Embodiment 1, the plurality of cutting grooves 2.7 are evenly distributed along the helical direction of the reverse compression helical blades 2.6. The reverse compression helical blades 2.6 on the reverse thrust section 2.4 are arranged in 2-3 turns.

[0026] The cutting groove 2.7 is a groove-shaped notch set on the reverse compression spiral blade 2.6. The cutting surface of the notch is provided with a cutting edge 2.8, which is made of cemented carbide. The cutting edge 2.8 can better crush high-density materials. The material is crushed as it is squeezed through the cutting groove 2.7. The material enters the cutting groove 2.7 on the adjacent reverse compression spiral blade 2.6 from the rear cutting groove 2.7 and is crushed again. This crushing process continues until the material enters the front end of the feeder and falls into the cooking container, completing the feeding process. The thorough crushing allows steam to penetrate the cell walls of the biomass raw material more quickly and cook it rapidly.

[0027] Furthermore, reinforcing ribs are provided on the corresponding spiral shaft tubes 1 of the compression section 2.2 and the feed plug section 2.3. The purpose is to give the spiral shaft tube 1 of this section higher compressive strength.

[0028] The pressure screw feeder of this invention features a reverse thrust section 2.4 at the front end of the screw shaft 2. The reverse compression screw blades 2.6 on the reverse thrust section 2.4 can reverse-compress the material, causing it to be compressed bidirectionally in the feed plug section 2.3. This significantly increases the density compared to traditional feeders. As the screw shaft 2 rotates, the high-density material is crushed and squeezed out from the cutting groove 2.7, completing the feeding process. This thorough crushing allows steam to penetrate the cell walls of the biomass raw materials more quickly, resulting in rapid cooking and maturation. Furthermore, the pressure of the gas medium inside the cooking vessel acts on the dense material in the feed plug section 2.3, preventing gas from escaping from the feeder. The material leaks out and is ejected back from the feeder inlet; the material in the feed plug section 2.3 is continuously pushed forward by the material in the rear, thus continuously feeding the material into the digester. Because the feed plug formed by this feeder is dense enough, it can withstand a large saturated steam pressure. Tests have shown that it can achieve the process of high-temperature cooking and maturation after continuous feeding under high pressure of 1.6MPa saturated steam and high temperature of 207℃, which is far higher than the existing 0.8MPa conditions. It can fully soften the material and obtain higher product quality, making it suitable for promotion and use in the paper, cellulosic ethanol, and pharmaceutical industries.

Claims

1. A pressure screw feeder, comprising a screw shaft tube, a screw shaft, and a drive motor, characterized in that: The spiral shaft is divided into a conveying section, a compression section, a material plug section, and a reverse thrust section. The conveying section and the compression section are equipped with spiral blades, the material plug section is not equipped with spiral blades, and the reverse thrust section is equipped with reverse compression spiral blades. The pitch between the spiral blades in the compression section gradually decreases, and the reverse compression spiral blades in the reverse thrust section are equipped with several cutting grooves.

2. The pressure screw feeder as described in claim 1, characterized in that: The cutting groove forms an angle with the axis of the helical shaft.

3. A pressure screw feeder as described in claim 1, characterized in that: The cutting groove has a cutting edge made of cemented carbide.

4. A pressure screw feeder as described in claim 1, characterized in that: The spiral shaft tube is provided with a feed inlet, which is connected to the mixing and feeding device.

5. A pressure screw feeder as described in claim 1, characterized in that: The conveying section, compression section, feed plug section, and reverse thrust section are arranged in sequence.

6. A pressure screw feeder as described in claim 1, characterized in that: The inner wall of the spiral shaft tube is provided with anti-slip strips to prevent material rotation.

7. A pressure screw feeder as described in claim 1, characterized in that: The spiral shaft tube is provided with drainage holes at the positions corresponding to the compression section and the feed plug section.

8. A pressure screw feeder as described in claim 1, characterized in that: The plurality of cutting grooves are evenly distributed along the helical direction of the reverse compression helical blade.

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