A kind of anti-corrosion wood particle drying production line

Abstract

The application relates to the field of anti-corrosion wood drying equipment, and particularly discloses an anti-corrosion wood particle drying production line which comprises a pre-drying section, an anti-corrosion section and a post-drying section arranged in sequence; the pre-drying section and the post-drying section are both of the roller type drying equipment, the anti-corrosion section comprises a weighing mechanism for weighing wood particles and a spraying mechanism for spraying preservatives, so as to control the flow of the sprayed preservatives according to the flow of the wood particles entering the anti-corrosion section; the heat generated by the heat source mechanism of the pre-drying section is directly sent into the drying cylinder from the feeding end of the drying cylinder; the heat generated by the heat source mechanism of the post-drying section firstly heats the drying cylinder from the outside of the drying cylinder and then is sent into the drying cylinder from the feeding end of the drying cylinder; the wood particles discharged from the pre-drying section are sent to the post-drying section through the middle feeding mechanism, and the anti-corrosion section is arranged in the middle of the middle feeding mechanism. The production line is beneficial to reducing the transfer of wood particles and improving the drying automation degree while ensuring the drying efficiency.

Description

Technical Field

[0001] This invention relates to the field of preservative-treated wood drying equipment, and more specifically to a preservative-treated wood pellet drying production line. Background Technology

[0002] Wood particle reinforced composite flooring is a new type of special board material for railway flatcars, researched by the Institute of Metals and Chemistry of China Academy of Railway Sciences Group Co., Ltd. (Patent name: A composite wood floor for railway flatcars, patent application number: 202121405576.8). This type of board material can replace the existing wooden flooring for railway flatcars, and its strength, nail-holding power, corrosion resistance, and fire resistance are all superior to existing wooden flooring.

[0003] The main raw material of wood particle reinforced composite flooring is wood particles. After drying, the wood particles are glued together under pressure to form the flooring. The most significant characteristic of this flooring is its excellent corrosion resistance and fire resistance. These properties are primarily due to the addition of appropriate additives during the flooring's production process. For example, to enhance the flooring's corrosion resistance, the wood particles must first undergo a preservative treatment. This preservative process involves pre-drying the wood particles to reduce their moisture content to below 30%, then spraying a preservative agent and mixing it with the particles to achieve the desired corrosion effect. After this preservative treatment, the wood particles are dried again to control the moisture content to around 10%.

[0004] The processing of wood particles, the main raw material for wood particle reinforced composite flooring, includes pre-drying, preservative spraying, and post-drying. Therefore, how to design a mass production line for wood particle preservative drying to achieve automated production of wood particle pre-drying, preservative treatment, and post-drying is the main problem that this solution needs to solve.

[0005] Secondly, in the post-drying stage, to prevent the preservatives from becoming ineffective, the drying temperature should not exceed 150℃; simultaneously, according to production needs, the output must reach 2.5t / h. Currently, existing dryers in China include drum dryers and mesh belt dryers. Drum dryers use end ignition for heating, meaning the flame generated by the burner is directly injected into the drum, and the temperature around the flame is the highest, resulting in localized drying temperatures reaching 300℃-400℃, which cannot meet the drying requirements of wood pellets after preservation. Mesh belt dryers can meet the temperature requirements, but their working efficiency is very low, with a maximum capacity of only 0.5t / h. Therefore, existing dryers cannot meet the drying requirements of wood pellets after preservation. Summary of the Invention

[0006] The purpose of this invention is to provide a preservative-treated wood pellet drying production line to achieve continuous production of wood pellets through pre-drying, preservative treatment, and post-drying; at the same time, it solves the problem that when using existing drum drying equipment to dry preservative-treated wood pellets, uneven drying temperature distribution and localized high drying temperatures can lead to the failure of preservatives.

[0007] The preservative-treated wood particle drying production line includes a pre-drying section, a preservative-treated section, and a post-drying section arranged sequentially; both the pre-drying section and the post-drying section use drum-type drying equipment.

[0008] The drum-type drying equipment includes a drying drum that can be driven to rotate by a drive mechanism and a heat source mechanism that provides heat to the drying drum. One end of the drying drum is provided with a feeding end and the other end is provided with a discharging end. A wood particle accumulation trough is provided below the discharging end.

[0009] The anti-corrosion section includes a weighing mechanism for weighing wood particles and a spraying mechanism for spraying preservatives. Both the weighing mechanism and the spraying mechanism are electrically connected to a controller. The weighing mechanism feeds back the weight data of the wood particles to the controller, and the controller adjusts the flow rate of the preservative sprayed by the spraying mechanism in real time based on the received weight data of the wood particles.

[0010] The drum-type drying equipment in the pre-drying section is the first drying equipment. The heat generated by the heat source mechanism of the first drying equipment is directly sent into the drying cylinder from the feed end of the drying cylinder. The drum-type drying equipment in the post-drying section is the second drying equipment. The heat generated by the heat source mechanism of the second drying equipment first heats the drying cylinder from the outside of the drying cylinder and then sends it into the drying cylinder from the feed end of the drying cylinder.

[0011] The wood pellets discharged from the first drying equipment are fed to the second drying equipment through the central feeding mechanism, and the anti-corrosion section is located in the middle of the central feeding mechanism.

[0012] The beneficial effects of this plan are as follows:

[0013] (1) In this technical solution, the drying production line of the preservative wood pellets mainly consists of three sections, including the pre-drying section, the preservative section and the post-drying section. Both the pre-drying section and the post-drying section adopt drum drying efficiency to make the drying production line have higher drying efficiency. Secondly, since the preservative effect can only be more effective after the moisture content of the wood pellets is reduced to a certain level, integrating the preservative into the drying production line is beneficial to reduce the transfer of wood pellets and improve the degree of automation and efficiency of drying.

[0014] (2) The heat source mechanism of the pre-drying section directly sends the heat into the drying cylinder (such as the flame generated by the burner being directly sprayed into the drying cylinder). The disadvantage of this drying method is that it is easy to cause uneven heat distribution in the drying cylinder and high temperature in the drying cylinder. Its advantage is that the hot airflow is fast in the drying cylinder. The above advantages and disadvantages are fully utilized in the pre-drying stage. Since the wood particles have a high moisture content in the pre-drying stage, although there are problems of uneven heat distribution and high temperature in the drying cylinder, it will not cause the wood particles to carbonize and fail. On the contrary, the local high temperature and rapid airflow are more conducive to the rapid evaporation of moisture and its removal from the drying cylinder, so that the wood particles can be dried quickly.

[0015] (3) The spraying mechanism of the anticorrosion section adjusts the amount of preservative sprayed according to the amount of wood particles entering the anticorrosion section per unit time, so as to avoid too much or too little preservative sprayed. This ensures that the wood particles fully absorb the preservative while improving the utilization rate of the preservative. Secondly, controlling the amount of preservative sprayed into the wood particles in the anticorrosion section within a suitable range can prevent the moisture content of the wood particles entering the drying section from being too high, which would prolong the drying time of the wood particles.

[0016] (4) In the post-drying section, since high temperature will cause the preservative to fail, local high temperature should be avoided and the drying temperature should be reduced in the post-drying section. In the method of directly spraying heat into the drying cylinder, local high temperature is mainly generated at the feed end of the drying cylinder. Therefore, in the second drying equipment, the heat is first transferred from the outside of the drying cylinder to the inside of the drying cylinder through heat conduction. Heat conduction promotes the uniform distribution of heat and avoids the local high temperature from lowering the temperature inside the drying cylinder. Secondly, the heat-conducted airflow with residual heat is sent into the drying cylinder, which improves the heat utilization efficiency. Moreover, the hot airflow is sent into the drying cylinder, which enhances the airflow inside the drying cylinder and is conducive to timely discharge of moisture.

[0017] Preferred Option 1: As a further optimization of the basic option, the heat source mechanism adopts a gas burner. Gas burners have a simple structure and are easy to install.

[0018] Preferred Option 2: As a further optimization of Preferred Option 1, the second drying equipment also includes a combustion chamber surrounding the outer periphery of the drying cylinder. The burner head of the gas burner extends into the combustion chamber from the lower part of the combustion chamber. A heat insulation cover is provided above the burner head to block the flame and prevent the flame from directly heating the drying cylinder. One end of the waste heat recovery pipe is connected to the top of the combustion chamber, and the other end of the waste heat recovery pipe is connected to the feed end of the drying cylinder.

[0019] In the preferred embodiment, by arranging a combustion chamber around the outer periphery of the drying cylinder and installing a heat insulation hood inside the combustion chamber, the flame generated by the gas generator impacts the heat insulation hood, preventing the flame from directly heating the drying cylinder. Since the combustion chamber surrounds the drying cylinder, the hot airflow forms a circulation along the side wall of the combustion chamber under the guiding effect of the heat insulation hood, thereby achieving a uniform temperature range within the combustion chamber. The heat is then transferred to the interior of the drying cylinder through heat conduction. Thus, by regulating the temperature inside the combustion chamber, the temperature inside the drying cylinder can be made uniform, avoiding localized high temperatures.

[0020] Preferred Option 3: As a further optimization of Preferred Option 2, one drying chamber and one gas burner constitute a drying group. Multiple drying groups are provided around the outer periphery of the drying cylinder of the second drying equipment, and these groups are evenly distributed along the axial direction of the drying cylinder. The combustion chamber is segmented, which facilitates the installation of the combustion chamber and the drying cylinder, and also makes it easier to install the support structure for the drying cylinder. Furthermore, segmenting the combustion chamber reduces the combustion chamber space, which is beneficial for the uniform distribution of airflow inside the combustion chamber.

[0021] Preferred Option 4: As a further optimization of Preferred Option 3, the drying cylinder is supported by rollers, and space is provided between adjacent drying groups for installing rollers.

[0022] Preferred Option 5: As a further optimization of Preferred Option 4, the first drying equipment also includes a transfer hopper. The wood particles discharged from the first drying equipment are introduced into the transfer hopper through a feeding mechanism, and the transfer hopper is connected to the second drying equipment through the central feeding mechanism.

[0023] In the preferred option five, since the drying temperature of the pre-drying section is high and the moisture content of the output wood pellets is also higher than that of the output wood pellets from the post-drying section, the drying output of the pre-drying section is high per unit time. Therefore, a transfer silo is set up to facilitate the temporary storage of wood pellets.

[0024] Option Six: As a further optimization of Option Five, this option also includes a spare material storage trough, which can feed materials to the anti-corrosion section or the transfer silo via a feeding mechanism. When purchasing wood pellets, wood pellets with a moisture content below 30% can also be purchased directly. Wood pellets with a moisture content below 30% do not require pre-drying and can be directly transferred to the transfer silo or the anti-corrosion section.

[0025] Preferred Option Seven: As a further optimization of Preferred Option Six, the discharge end of the drying cylinder is connected to a cyclone separator, and the air outlet of the cyclone separator is connected to a spray tower. The combination of the cyclone separator and the spray tower can prevent dust and sawdust generated during the drying process from being directly emitted into the air, thus reducing environmental pollution.

[0026] Preferred Option 8: As a further optimization of Preferred Option 7, an air supply duct is provided at the feed end of the drying cylinder, and a feed hopper is fixed to one end of the air supply duct near the drying cylinder; the burner head of the gas burner of the first drying equipment extends axially into the air supply duct; the waste heat recovery pipe of the second drying equipment is connected to the side of the air supply duct and communicates with the air supply duct. Providing an air supply duct can improve the uniformity of heat entering the drying cylinder to a certain extent, and also facilitates the installation of the feed hopper.

[0027] Preferred Option Nine: As a further optimization of Preferred Option Eight, the central feeding mechanism adopts a belt feeder, which includes a front feeding section and a rear feeding section, with the anti-corrosion section located between the front and rear feeding sections; the anti-corrosion section also includes an anti-corrosion silo and an agitator located at the bottom of the anti-corrosion silo, and the weighing mechanism adopts a belt scale located at the top of the anti-corrosion silo, with a discharge port at the bottom of the anti-corrosion silo; the front feeding section feeds the wood particles to the belt scale, and the rear feeding section receives the wood particles discharged from the discharge port.

[0028] In the preferred option nine, a belt scale is used as the load-bearing mechanism. This is because its structure is simple and it is easy to install and coordinate with other devices in the anti-corrosion section. In addition, the belt scale is easy to connect with the belt feeder. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the production line of the present invention;

[0030] Figure 2 This is a schematic diagram of the pre-drying section of the present invention;

[0031] Figure 3 This is a schematic diagram of the anti-corrosion section of the present invention;

[0032] Figure 4 This is a schematic diagram of the structure of the drying section of the present invention.

[0033] Figure 5 This is a cross-sectional view of the drying cylinder and combustion chamber in Embodiment 1 of the present invention;

[0034] Figure 6 This is a cross-sectional view of the drying cylinder and combustion chamber in Embodiment 5 of the present invention;

[0035] Figure 7 This is a cross-sectional view of the air supply duct of the post-drying section in Embodiment 5 of the present invention;

[0036] Figure 8 This is a cross-sectional view of the air supply duct of the post-drying section in Embodiment 5 of the present invention, presented in state 1.

[0037] Figure 9 This is a cross-sectional view of the air supply duct of the post-drying section in Embodiment 2 of the present invention, presented in state 2. Detailed Implementation

[0038] The following detailed description illustrates the specific implementation method:

[0039] The reference numerals in the accompanying drawings include: pre-drying section 010, transfer silo 011, anti-corrosion section 020, belt scale 021, spray head 023, post-drying section 030, belt feeder 040, centrifugal fan 015, drying cylinder 012, spray head 023, anti-corrosion silo 022, roller ring 311, driven gear 312, air duct 314, lifting plate 315, combustion chamber 320, burner 321, heat insulation cover 322, cover body 330, feed hopper 014, material chute 332, air supply duct 013, waste heat return pipe 341, flexible wire mesh 343, memory spring 344, rigid wire mesh 342, drive motor 350, discharge hopper 361, cyclone separator 362, and spray tower 370.

[0040] Example 1:

[0041] As attached Figure 1 As shown, the preservative-treated wood particle drying production line includes a pre-drying section 010, a preservative-treated section 020, and a post-drying section 030 arranged sequentially from right to left. These sections are connected sequentially by a feeding mechanism, which uses a belt conveyor 040. Both the pre-drying section 010 and the post-drying section 030 employ drum-type drying equipment. The drum-type drying equipment mainly includes a horizontally placed drying cylinder 012 and a drive mechanism that drives the drying cylinder 012 to rotate. The drying cylinder 012 is supported by multiple sets of rollers, allowing it to roll on the rollers. The drying cylinder 012 is inclined at an angle of 3%, with the higher section being the feed end and the lower section being the discharge end. The drive mechanism includes a drive motor 350, a reducer, and a meshing drive gear and gear ring. The gear ring is fixedly fitted around the outer circumference of the drying cylinder 012, and the drive gear is keyed to the output shaft of the reducer. The inner wall of the drying cylinder 012 is provided with several lifting plates 315. During the rotation of the drying cylinder 012, the lifting plates 315 have a throwing effect on the wood particles to promote uniform heating of the wood particles.

[0042] As attached Figure 1 Appendix Figure 2As shown, the pre-drying section 010 includes a first drying device and a transfer hopper 011. An air duct 013, connected to the end of the first drying device, is located at the feed end of the first drying device. The air duct 013 is fixed to the ground by a steel frame structure. A feed hopper 014 is located at the left end of the air duct 013, and a belt conveyor 040 feeds wood pellets into the feed hopper 014. The heat source mechanism of the first drying device is a gas burner 321, which is installed at the right end of the air duct 013, and the right end of the air duct 013 is closed. The burner head of the gas burner 321 extends from the right end of the air duct 013 into the air duct 013 to spray flames into the air duct 013. The transfer hopper 011 is located on the right side of the first drying device. The top of the transfer hopper 011 is open, and its bottom has a closable discharge port. The wood pellets pre-dried by the first drying device are fed into the transfer hopper from the top via the belt conveyor 040. In addition, a spare material trough is provided on the side of the first drying equipment. The spare material trough can feed wood particles that do not need to be pre-dried directly from the top of the transfer silo 011 into the transfer silo 011 through the belt feeder 040.

[0043] As attached Figure 3 As shown, the anti-corrosion section 020 includes an anti-corrosion silo 022, a belt scale 021 located above the anti-corrosion silo 022, an agitator located inside and below the anti-corrosion silo 022, and a spraying mechanism for spraying preservative into the anti-corrosion silo 022. The top of the anti-corrosion silo 022 is open, and the bottom of the anti-corrosion trough has a discharge port. Both the belt scale 021 and the spraying mechanism are electrically connected to the controller. The spraying mechanism includes spray heads 023 and a spray pump connected to each other. The belt scale 021 feeds back the weight data of the wood particles fed into the anti-corrosion silo 022 per unit time to the controller. The controller adjusts the flow rate of the preservative delivered by the spray pump in real time according to the weight value of the wood particles. The spray pump delivers the preservative into the spray heads 023, disperses it, and sprays it onto the wood particles. The agitator then stirs the wood particles to ensure that they absorb the preservative evenly. A central feeding mechanism is provided between the pre-drying section 010 and the post-drying section 030. The central feeding mechanism includes a front feeding section and a rear feeding section. The anti-corrosion section 020 is located between the front feeding section and the rear feeding section. One end of the front feeding section is located below the transfer silo 011, and the other end of the front feeding section is connected to the belt scale 021 to feed materials to the anti-corrosion section 020. One end of the rear feeding section is located below the discharge port of the anti-corrosion silo 022, and the other end of the rear feeding section is connected to the post-drying section 030.

[0044] As attached Figure 4As shown, the post-drying section 030 includes a second drying device and a waste heat recovery mechanism. The outer periphery of the drying cylinder 012 of the second drying device is covered with combustion chambers 320. Four sections of combustion chambers 320 are arranged at intervals. Roller rings 311 and toothed rings corresponding to the support rollers are located within the gaps between the combustion chambers 320. The combustion chambers 320 surround the outer periphery of the drying cylinder 012, meaning the drying cylinder 012 extends through the center of the combustion chambers 320, thus making the combustion chambers 320 annular. The lower sidewall of the combustion chamber 320 is connected to a burner 321, meaning the burner head of the burner 321 extends into the combustion chamber 320 through the sidewall, and the flame jet direction is perpendicular to the axis of the drying cylinder 012. To prevent the flames emitted by the burner 321 from directly hitting the drying cylinder 012 and directly heating it, as shown in the attached diagram... Figure 5 As shown, a heat insulation cover 322 is provided inside the combustion chamber 320 corresponding to the position of the burner head. The heat insulation cover 322 is made of refractory bricks and covers the flame. An opening is provided on the side wall of the heat insulation cover 322, through which the hot airflow inside the heat insulation cover 322 enters the combustion chamber 320 and flows along the side wall of the combustion chamber 320 to heat the drying cylinder 012. The top side wall of the combustion chamber 320 is an arc surface coaxial with the drying cylinder 012 to guide the hot airflow; while the lower part of the combustion chamber 320 is square to facilitate the installation of the heat insulation cover 322 and the burner 321, and also to facilitate the use of a steel frame structure to fix the combustion chamber 320 to the ground. In this embodiment, the burner 321 uses natural gas as fuel and is a 400,000 kcal burner 321 to ensure that the combustion chamber 320 has sufficient heat for continuous heating.

[0045] As attached Figure 4 As shown, the feeding end of the drying cylinder 012 of the second drying equipment is connected to the cover 330. The top of the cover 330 is provided with a feeding hopper 014. The inner side wall of the cover 330 is welded with an inclined sliding groove 332 located below the feeding hopper 014 and extending into the drying cylinder 012. The rear feeding section of the middle feeding structure feeds wood particles to the feeding hopper 014. An air supply duct 013 is fixedly connected to the right side of the cover 330. The air supply duct 013 passes through the right side wall of the cover 330 and communicates with the feeding end of the drying cylinder 012. The air supply duct 013 is connected to the combustion chamber 320 through a waste heat return pipe 341. One end of the waste heat return pipe 341 is connected to the top of the combustion chamber 320, and the other end of the waste heat return pipe 341 is connected to the side of the air supply duct 013. Four waste heat recovery pipes 341 send the hot airflow from each combustion chamber 320 into the air supply duct 013 for mixing before entering the drying cylinder 012. This promotes uniform heat distribution within the drying cylinder 012, ensuring even drying of the wood particles. (See attached image) Figure 4As shown, the horizontal section of the waste heat return pipe 341, which is parallel to the drying cylinder 012, is in the same vertical plane, and the vertical plane is located in front of or behind the drying cylinder 012, which facilitates the installation of a steel frame to support the waste heat return pipe 341; the cover 330 and the air supply duct 013 are supported by the steel frame structure and fixed to the ground.

[0046] In this design, the heat carried by the flame injected by the gas burner 321 is dispersed within the combustion chamber 320 and then heated to the drying cylinder 012 via heat conduction. This avoids localized high temperatures, ensuring a relatively uniform temperature on the sidewalls of the drying cylinder 012 and promoting uniform internal temperature. Even if the heat carried by the flame is not completely uniformly distributed within the drying chamber, the rotating state of the drying cylinder 012 and the time required for heat conduction to raise the temperature prevent excessively high localized temperatures on the sidewalls of the drying cylinder 012. Secondly, after the hot airflow in the combustion chamber 320 conducts heat to the drying cylinder 012, its temperature will decrease. Furthermore, the waste heat return pipe 341 is connected to the drying chamber at the top, which is relatively far from the burner 321. Therefore, the top of the burner 321 is the location with the relatively lower internal temperature. In other words, the temperature carried by the flame is reduced after being dispersed and transferred within the combustion chamber 320 before entering the drying cylinder 012 through the air duct 013. This prevents excessively high temperatures inside the drying cylinder while fully utilizing heat and reducing fuel consumption. To further reduce heat loss, the side walls of the combustion chamber 320 are filled with heat insulation covers 322, and the portion of the side walls of the drying cylinder 012 outside the combustion chamber 320 is also filled with heat insulation covers 322.

[0047] Both the first and second drying units are connected to cyclone separators 362 at their discharge sections. The discharge ends of the drying cylinders 012 of both the first and second drying units are connected to discharge hoppers 361. Discharge hoppers 361 are four-sided enclosed structures, with the discharge end of the drying cylinder 012 extending into the discharge hopper 361. A discharge port is located at the bottom of the discharge hopper 361 for the wood particles to be discharged. A moisture outlet is located at the top of the discharge hopper 361, and this outlet is connected to the cyclone separators 362.

[0048] The outlets of the cyclone separators 362 in both the first and second drying equipment are connected to the bottom of the spray tower 370. This means that the humid air flows upwards from the bottom of the spray tower 370 while being sprayed, thereby adsorbing sawdust and dust. A sedimentation tank is provided at the bottom of the spray tower 370 to settle the sawdust and dust. The sprayed gas is discharged from the top of the spray tower 370. The wood pellets discharged from the discharge hopper 361 of the first drying equipment are fed into the transfer silo 011 via the belt conveyor 040.

[0049] Example 2:

[0050] The difference between Embodiment 2 and Embodiment 1 is that, in Embodiment 2, the discharge end of the drying cylinder 012 of the first drying equipment is directly connected to the centrifugal fan 015 to suck out the dried wood particles and send them into the cyclone separator 362. After cyclone separation, the airflow carrying dust and a small amount of wood chips is discharged from the top of the cyclone separator 362, and the wood particles are discharged from the bottom of the cyclone separator 362 and sent to the transfer silo 011 by the belt conveyor 040.

[0051] Example 3:

[0052] Based on Embodiment 2, the air outlet of the cyclone separator 362 connected to the first drying equipment is connected to the air supply duct 013 of the second drying equipment via a waste heat pipe. In the first drying equipment, the heat generated by the combustion of the burner 321 is directly injected into the drying cylinder, resulting in a relatively high temperature inside the drying cylinder. At the same time, the hot airflow travels a short distance, so the airflow discharged from the drying cylinder 012 still contains a large amount of waste heat. Sending this waste heat into the drying cylinder 012 of the second drying equipment can improve the heat utilization efficiency.

[0053] Example 4:

[0054] Based on Example 3, a dehumidification isolation layer is provided inside the waste heat pipe. The dehumidification isolation layer is filled with desiccant to absorb moisture, thereby reducing the humidity of the hot airflow entering the second drying equipment and improving the drying efficiency.

[0055] Example 5:

[0056] The difference between Example 5 and other examples is as follows: Figure 7 As shown, an arc-shaped rigid wire mesh 342 is provided at the corresponding position where the air supply duct 013 connects to the waste heat return pipe 341, and is located inside the air supply duct 013. The rigid wire mesh 342 can be made of iron wire mesh; the iron wire mesh is fixed to the inner side wall of the air supply duct 013. The hot airflow discharged from the waste heat return pipe 341 enters the air supply duct 013 after passing through the iron wire mesh. Since the temperature of each combustion chamber 320 entering the waste heat return pipe 341 may be different, there is a certain resistance when the hot airflow passes through the iron wire mesh, which promotes a certain degree of mixing of the hot airflow inside the iron wire mesh, and then the hot airflow enters the air supply duct 013 evenly after being distributed by the iron wire mesh, thus promoting the formation of a uniform hot airflow inside the air supply duct 013.

[0057] As attached Figure 8As shown, a flexible wire mesh 343 is installed inside the left end of the air supply duct 013. The flexible wire mesh 343 can be made of fine stainless steel wire mesh. The flexible wire mesh is woven from narrow strips of stainless steel, with a width of 3-6 mm and a thickness of 0.2-0.3 mm. After being stretched, the stainless steel wire mesh forms a conical shape, and its outer edge is fixed to the side wall of the air supply duct 013. A memory spring 344 (a spring made of shape memory alloy wire) is connected to the center of the stainless steel wire mesh, and the other end of the memory spring 344 is fixed to the side wall of the air supply duct 013. When the temperature inside the air supply duct 013 is below 120℃, the length of the memory spring 344 shortens, and the stainless steel wire mesh is stretched to the right. (See attached diagram.) Figure 9 As shown, when the temperature inside the air duct 013 exceeds 120℃, the length of the memory spring 344 elongates. At this time, due to the airflow flowing to the left, the stainless steel wire mesh expands to the left. Since the stainless steel wire mesh is woven from narrow strips of stainless steel, the projection area of ​​the wire mesh onto the cross-section of the drying cylinder is smaller for holes near the edge and larger for holes near the center. After being distributed by the stainless steel wire mesh, the airflow inside the air duct 013 enters the drying cylinder 012. When the stainless steel wire mesh stretches to the right into a conical shape, due to the tendency of fluids to adhere to the surface of an object, more hot airflow from the outer edge of the wire mesh will flow out, while less will flow out from the center. Conversely, when the stainless steel wire mesh expands to the left, due to the tendency of fluids to adhere to the surface of an object, more hot airflow from the center of the air duct 013 will flow out, while less will flow out from the outer edge.

[0058] As attached Figure 6 , 8 As shown, a duct 314 is provided at the center of the drying cylinder 012. The duct 314 is fixed to the inner wall of the drying cylinder 012 by spokes. One end of the duct 314 is open towards the air supply duct 013, and the other end of the duct 314 is closed. Several air holes are provided on the duct 314 corresponding to the part outside the combustion chamber 320 (i.e., the installation area of ​​the roller ring 311 and the driven gear 312).

[0059] When the temperature inside the air supply duct 013 is higher than 120℃, it indicates that the temperature of the side wall of the drying cylinder 012 is too high. At this time, the heat transfer efficiency of the combustion chamber 320 to the drying cylinder 012 is reduced, and the temperature near the inner side wall of the drying cylinder 012 should not be increased further. Therefore, the stainless steel wire mesh expands to the left, so that more hot airflow discharged from the air supply duct 013 flows out from the middle of the stainless steel wire mesh and enters the air duct 314 to increase the center temperature of the drying cylinder 012. After entering the air duct 314, the hot airflow is discharged from the air control to enter the area outside the combustion chamber 320, thereby improving the heat utilization efficiency.

[0060] When the temperature inside the air duct 013 is below 120℃, it indicates that the temperature of the side wall of the drying cylinder 012 is too low, and the heat transfer efficiency of the combustion chamber 320 to the drying cylinder 012 is relatively high. At this time, it is necessary to further increase the temperature near the inner side wall of the drying cylinder 012. Therefore, the stainless steel wire mesh is stretched to the right so that more hot airflow discharged from the air duct 013 flows out from the outer edge of the stainless steel wire mesh and enters the air duct 314, which helps to increase the temperature near the side wall of the drying cylinder 012 and improve the drying efficiency. At the same time, some hot airflow enters the middle of the drying cylinder 012 to ensure the temperature in the middle of the drying cylinder 012.

[0061] The above descriptions are merely embodiments of the present invention, 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 the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A production line for drying preservative wood particles, characterized in that: The wood particle drying device comprises a pre-drying section, a preservative section and a post-drying section arranged in sequence. The drum-type drying equipment comprises a drying drum body driven to roll by a driving mechanism and a heat source mechanism for providing heat to the drying drum body. The preservative section comprises a weighing mechanism for weighing wood particles and a spraying mechanism for spraying preservatives. The heat source mechanism of the pre-drying section is a first drying equipment, and the heat generated by the heat source mechanism is directly sent into the drying drum body from the feeding end of the drying drum body. The feeding end of the drying drum body of the second drying equipment is connected with a cover body, the right side of the cover body is fixedly connected with a blowing cylinder, and the heat generated by the heat source mechanism of the second drying equipment is first used to heat the drying drum body from the outside and then sent into the drying drum body from the feeding end of the drying drum body through the blowing cylinder. The left end of the blowing cylinder is internally provided with a flexible wire mesh, the flexible wire mesh is made of stainless steel wire mesh, the outer edge of the stainless steel wire mesh is fixed on the side wall of the blowing cylinder, the center of the flexible wire mesh is connected with a memory spring, one end of the memory spring is fixed on the side wall of the blowing cylinder, the length of the memory spring is shortened, the stainless steel wire mesh is in a conical cylinder-shaped stretching state away from one end of the drying drum body of the second drying equipment, the length of the memory spring is elongated, and the stainless steel wire mesh is expanded to one side of the drying drum body of the second drying equipment under the influence of the airflow flowing to the drying drum body of the second drying equipment.

2. A production line for drying of impregnated wood particles according to claim 1, characterized in that: The wood particles discharged from the first drying equipment are sent to the second drying equipment through the middle feeding mechanism, and the preservative section is arranged in the middle part of the middle feeding mechanism.

3. A production line for drying of impregnated wood particles according to claim 2, characterized in that: The heat source mechanism adopts a gas burner.

4. A wood pellet drying production line for preserving wood pellets according to claim 3, characterized in that: The second drying equipment further comprises a combustion chamber surrounding the outer periphery of the drying drum body, the combustion head of the gas burner extends into the combustion chamber from the lower part of the combustion chamber, the upper part of the combustion head is provided with a heat shield for blocking the flame to avoid directly heating the drying drum body, the top of the combustion chamber is connected with one end of a waste heat recycling pipe, and the other end of the waste heat recycling pipe is in communication with the feeding end of the drying drum body.

5. A production line for drying and preserving wood particles according to claim 4, characterized in that: One drying chamber and one gas burner constitute one drying group, and the outer periphery of the drying drum body of the second drying equipment is provided with a plurality of drying groups which are uniformly distributed along the axial direction of the drying drum body.

6. A production line for drying and preserving wood particles according to claim 5, characterized in that: The drying drum body is supported by carrier rollers, and spaces for installing the carrier rollers are arranged between adjacent drying groups.

7. A production line for drying and preserving wood particles according to claim 6, characterized in that: The first drying equipment further comprises a transfer bin, the wood particles discharged from the first drying equipment are introduced into the transfer bin through the feeding mechanism, and the transfer bin is connected with the second drying equipment through the middle feeding mechanism.

8. A kiln line for drying preservative-treated wood particles according to any one of claims 1-7, characterized in that: A standby stacking groove is further arranged, and the standby stacking groove can feed wood particles to the preservative section or the transfer bin through the feeding mechanism. The feeding end of the drying drum body is connected with a cyclone separator, and the air outlet of the cyclone separator is connected with a spraying tower.

9. A wood pellet drying production line for preserving wood pellets according to claim 8, characterized in that: The feeding end of the drying cylinder is provided with a blowing cylinder, and the feeding hopper is fixed to one end of the blowing cylinder close to the drying cylinder; the combustion head of the gas burner of the first drying equipment extends into the blowing cylinder along the axial direction of the blowing cylinder; and the waste heat return pipe of the second drying equipment is connected to the side of the blowing cylinder and communicates with the blowing cylinder.

10. A wood pellet drying production line for preserving wood pellets according to claim 9, characterized in that: The middle feeding mechanism adopts a belt feeder, and the middle feeding mechanism comprises a feeding front section and a feeding rear section, and the anticorrosion section is arranged between the feeding front section and the feeding rear section; the anticorrosion section further comprises an anticorrosion bin and a stirrer arranged at the lower part of the anticorrosion bin; the weighing mechanism adopts a belt scale, and the belt scale is arranged at the upper part of the anticorrosion bin; and a discharge port is arranged at the bottom of the anticorrosion bin; the feeding front section feeds the wood particles to the belt scale, and the feeding rear section receives the wood particles discharged from the discharge port.

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