A cooking apparatus for wood fiber production

Abstract

This utility model provides a cooking device for wood fiber production, belonging to the field of wood fiber production equipment. The device includes a tank, a double-helix feeding system, and a zoned steam system. The double-helix feeding system operates using two counter-rotating synchronous screws, which are axially divided into a feeding section, a cooking section, and a discharging section, respectively adapted to the preheating chamber, mixing chamber, and supplementary steaming chamber of the cooking chamber. The steam injection mechanism is independently connected to each of the preheating chamber, mixing chamber, and supplementary steaming chamber via pipelines. This segmented, adapted screw structure avoids raw material accumulation and maintains a uniform feeding speed. The zoned steam system isolates the three chambers through partition plates, and the steam injection mechanism can independently control the steam parameters of each chamber, ensuring sufficient contact between the raw material and steam, reducing the deviation in fiber softening, improving the fiber softening qualification rate, and thus allowing the raw material to soften uniformly.

Description

Technical Field

[0001] This utility model relates to the field of wood fiber production equipment, specifically a cooking device for wood fiber production. Background Technology

[0002] MDF production uses wood as its core raw material, and the processing flow mainly includes four stages: raw material pretreatment, fiber preparation, hot pressing, and post-processing. Among these, wood fiber cooking is a key step in raw material pretreatment, directly determining the quality of subsequent fiber preparation. Specifically, after the wood raw material is sliced ​​and crushed to form wood chips with a particle size of 5-10mm, it needs to be softened by high-temperature steam in a cooking device. Under the action of steam, the lignin in the wood chips gradually degrades, and the binding force between fibers weakens, providing conditions for the subsequent hot mill to separate the wood chips into individual fibers.

[0003] Traditional wood fiber cooking equipment often employs an intermittent production mode. In intermittent equipment, raw materials tend to accumulate unevenly, making it difficult for steam to fully penetrate the material. This results in some fibers not being thoroughly cooked, failing to achieve the required softening level, and consequently causing "hard spots" on the surface of the MDF board, affecting product quality. Some continuous cooking equipment achieves continuous production through single-screw feeding, but during the single-screw propulsion process, raw materials tend to form "material arches," and excessive gaps can lead to steam short-circuiting, still resulting in poor cooking uniformity. Furthermore, their steam heating systems often use single-area injection, failing to adjust the steam supply according to the different states of the raw materials during the cooking process, further exacerbating the problem of incomplete cooking. Utility Model Content

[0004] In order to overcome some of the problems mentioned in the background above, this invention provides a cooking apparatus for wood fiber production.

[0005] The technical solution adopted by this utility model is as follows: A cooking device for wood fiber production includes a tank, a double spiral feeding system and a zoned steam system. The zoned steam system includes a steam injection mechanism and a steam cylinder. The steam injection mechanism is located on both sides of the tank. The steam cylinder is coaxially sleeved inside the tank. The inner wall of the steam cylinder forms a cooking chamber. Multiple partition plates are provided between the steam cylinder and the inner wall of the tank. The partition plates divide the gap between the steam cylinder and the tank into multiple areas, which are respectively arranged in sequence with the preheating chamber, mixing chamber and supplementary steaming chamber along the raw material conveying direction of the cooking chamber.

[0006] The double-helix feeding system is installed inside the steam cylinder. The double-helix feeding system includes two parallel spiral rods, which are divided into a feeding section, a cooking section, and a discharging section along the axial direction, respectively adapted to the preheating chamber, the mixing chamber, and the supplementary steaming chamber.

[0007] The steam injection mechanism is independently connected to the preheating chamber, mixing chamber, and supplementary steaming chamber via pipelines.

[0008] Furthermore, the two ends of the tank are detachably connected to sealing caps, the two ends of the spiral rod are respectively axially connected to the sealing caps, and the bottom of the tank is fixedly connected to a support base.

[0009] Furthermore, the tank body includes an insulated shell, the top of the insulated shell is provided with a feed inlet corresponding to the preheating chamber, and an exhaust pipe is provided corresponding to the supplementary steaming chamber. The bottom of the tank body is provided with a liquid collection tank and a discharge outlet corresponding to the supplementary steaming chamber.

[0010] Furthermore, the steam injection mechanism includes a steam pipe and an injection pipe. The steam pipe is arranged along the length of the tank, and three sets of injection pipes are provided on each side, corresponding to the preheating chamber, the mixing chamber, and the supplementary steaming chamber, respectively. Each set of injection pipes is equipped with an electric regulating valve, which can independently control the steam pressure and flow rate.

[0011] Furthermore, the steam cylinder is made of stainless steel and has a surface covered with ventilation holes.

[0012] Furthermore, the center distance between the two spiral rods is 1.2-1.5 times the diameter of the spiral rod, and the spiral blades rotate in opposite directions. Synchronous reverse rotation is achieved through gear meshing at the ends of the spiral rods, and one of the spiral rods is connected to a drive motor.

[0013] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0014] The twin-helix feeding system uses two opposing and synchronously rotating screws, along with a segmented and adaptable rod structure, to prevent raw material accumulation and ensure uniform feeding speed. The zoned steam system achieves three-compartment isolation through partition plates, and the steam injection mechanism independently controls the steam parameters of each compartment to ensure full contact between the raw material and steam, reduce fiber softening deviation, improve fiber softening qualification rate, and enable the raw material to be softened uniformly. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a cooking apparatus for producing wood fiber according to an embodiment of the present invention;

[0016] Figure 2 This is a front view schematic diagram of a cooking apparatus for producing wood fiber according to an embodiment of the present invention;

[0017] Figure 3 This is a left-side view of a cooking apparatus for producing wood fiber according to an embodiment of the present invention.

[0018] Figure 4 for Figure 3 Schematic diagram of the AA section along the middle edge;

[0019] Figure 5 for Figure 3 Schematic diagram of the BB section along the middle.

[0020] In the picture:

[0021] 1. Tank body; 11. Feed inlet; 12. Insulated shell; 13. Exhaust pipe; 14. Discharge outlet; 15. Collection tank; 2. Drive motor; 3. Steam injection mechanism; 31. Steam pipe; 32. Injection pipe; 4. Support base; 5. Steam cylinder; 51. Divider plate; 6. Screw rod; 61. Feeding section; 62. Cooking section; 63. Discharge section; 7. Sealing cover; 8. Cooking chamber; 81. Preheating chamber; 82. Mixing chamber; 83. Supplementary steaming chamber. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0023] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0024] like Figures 1-5 As shown, in some embodiments, a cooking apparatus for wood fiber production includes a tank 1, a twin-helix feeding system and a zoned steam system, with each part cooperating with the other to achieve efficient cooking.

[0025] The zoned steam system consists of a steam injection mechanism 3 and a steam cylinder 5. Specifically, the steam injection mechanism 3 is located on both sides of the tank body 1, and its function is to supply hot steam into the steam cylinder 5. The steam cylinder 5 is coaxially fitted inside the tank body 1, and the inner wall of the steam cylinder 5 forms a cooking chamber 8. Multiple annular partition plates 51 are provided between the outer wall of the steam cylinder 5 and the inner wall of the tank body 1. Through these partition plates 51, the gap between the steam cylinder 5 and the tank body 1 is divided into three areas, which are respectively configured to correspond to the preheating chamber 81, the mixing chamber 82, and the supplementary steaming chamber 83 arranged sequentially along the raw material conveying direction of the cooking chamber 8.

[0026] Each operating chamber is supplied with different amounts of steam through pipes by a dedicated steam injection mechanism 3, thereby ensuring that the temperature inside each chamber reaches the preset value.

[0027] Specifically, a double-helix feeding system is installed inside the steam cylinder 5. This system includes two parallel, counter-rotating spiral rods 6. Specifically, the spiral rods 6 are axially divided into a feeding section 61, a cooking section 62, and a discharging section 63, which are adapted to the preheating chamber 81, the mixing chamber 82, and the supplementary steaming chamber 83, respectively. Specifically, the feeding section 61 uses a large-pitch blade spacing to adapt to the preheating chamber 81, enabling the propulsion of loose raw materials. In the cooking section 62, the blade spacing is slightly smaller than that in the feeding section 61, adapting to the propulsion of compacted raw materials in the mixing chamber 82. In the discharging section 63, the blade spacing is the smallest, adapting to the propulsion of shaped raw materials in the supplementary steaming chamber 83. The blade edges are provided with rounded chamfers, which can effectively scrape the inner wall of the steam cylinder 5 while reducing raw material accumulation.

[0028] It should be noted that the double-helix feeding system uses two opposing and synchronously rotating screw rods 6, along with a segmented and adaptable rod structure, to avoid raw material accumulation and ensure uniform feeding speed. The zoned steam system achieves three-compartment isolation through the partition plate 51, and the steam injection mechanism 3 independently controls the steam parameters of each compartment to ensure that the raw material is in full contact with the steam, reduce the fiber softening deviation, improve the fiber softening qualification rate, and enable the raw material to be softened uniformly.

[0029] Furthermore, in some embodiments, the two ends of the tank body 1 are detachably connected to the sealing cover 7 by bolts, while the two ends of the screw rod 6 are axially connected to the sealing cover 7 by rolling bearings. This bearing connection method can ensure the stability of the screw rod 6 during rotation and effectively reduce the frictional resistance during operation. The bottom of the tank body 1 is welded and fixed with a support base 4 using a full welding process. The support base 4 is made of heavy steel structure, which provides a solid support foundation for the entire cooking device, ensuring that the equipment can maintain excellent stability during long-term continuous operation, and can also effectively absorb and disperse the vibration generated during the operation of the equipment.

[0030] Furthermore, in some embodiments, the tank 1 includes an insulated shell 12, and the steam cylinder 5 is disposed inside the insulated shell 12. The insulated shell 12 can effectively maintain the stability of the internal temperature of the tank 1 and reduce heat loss.

[0031] Specifically, a feed inlet 11 is provided at the top of the insulation shell 12 corresponding to the preheating chamber 81. This feed inlet 11 is connected to the feed port of the previous process, which facilitates the smooth and continuous addition of raw materials. At the same time, an exhaust pipe 13 is provided at the top of the corresponding supplementary steaming chamber 83. The exhaust volume can be adjusted according to actual needs to efficiently discharge excess steam generated during the cooking process and ensure the stability of the internal pressure of the tank 1.

[0032] Specifically, a liquid collection tank 15 is provided at the bottom of the tank body 1, which is inclined at 4° along the raw material conveying direction. The lowest end is located on the side of the feed inlet 11. A filter screen with a pore size of 0.8mm is provided in the tank to filter fiber debris. An automatic drain valve is connected to the bottom to ensure that condensate is discharged in time and there is no steam entrainment.

[0033] Finally, a discharge port 14 is provided on one side of the steaming chamber 83. This discharge port is connected to the feeding port of the next process to transport the cooked raw materials to the grinding chamber.

[0034] Furthermore, in some embodiments, the steam injection mechanism 3 includes a steam pipe 31 and an injection pipe 32. Specifically, the steam pipe 31 is arranged along the length of the tank 1, and three sets of injection pipes 32 are provided on each side. These injection pipes 32 are respectively connected to the steam pipe 31 and correspond to the preheating chamber 81, the mixing chamber 82, and the supplementary steaming chamber 83.

[0035] In particular, each set of spray pipes 32 is equipped with an electric regulating valve at the inlet end. According to preset parameters, the valve can precisely control the gentle temperature rise in the preheating stage, the uniform penetration in the mixing stage, and the deep treatment in the supplementary steaming stage. This significantly improves the temperature control accuracy of the cooking process and greatly enhances the adaptability and flexibility of the production process, providing a reliable guarantee for the production of high-quality wood fiber products.

[0036] Furthermore, in some embodiments, the steam cylinder 5 is made of stainless steel and is coaxially fitted inside the tank body 1, with a distance of 100mm between it and the inner wall of the tank body 1; vent holes are provided on its surface. Specifically, the opening rate is 22% in the area corresponding to the preheating chamber 81, 32% in the area corresponding to the mixing chamber 82, and 28% in the area corresponding to the supplementary steam chamber 83, to adapt to the steam demand of each chamber;

[0037] Two partition plates 51, made of fluororubber, are used. They are press-fitted with the outer wall of the steam cylinder 5 and the inner wall of the tank 1, ensuring good sealing performance. This significantly improves the efficiency, stability, and temperature uniformity of the cooking process, ultimately guaranteeing the consistent quality of the wood fiber products.

[0038] Furthermore, in some embodiments, the two spiral rods 6 are arranged in a parallel and symmetrical manner, and the distance between their central axes is precisely calculated and designed to be within the range of 1.2-1.5 times the diameter of the spiral rods 6. This ensures that the spiral blades have sufficient mixing space during operation, avoiding the accumulation and blockage of raw materials, and also ensures the continuity and efficiency of raw material transportation.

[0039] The helical blades on the two helical rods 6 are designed with completely opposite rotation directions. Strictly synchronized reverse rotation is achieved through a meshing gear set at the ends of the helical rods 6. This transmission method ensures the mechanical stability and operational reliability of the mixing process. One helical rod 6 is directly and rigidly connected to the output shaft of the drive motor 2 via a coupling, acting as the drive shaft to drive the entire mixing system smoothly. The other helical rod 6 acts as the driven shaft, achieving completely synchronized reverse rotation through a precision-machined gear meshing mechanism. This specially designed dual-helical-rod 6 synchronized reverse rotation system generates strong shear force and convection, significantly improving the mixing uniformity and cooking effect of the raw materials, ensuring the quality stability and consistency of the final product.

[0040] The specific operation process in this embodiment is as follows:

[0041] Raw material preparation:

[0042] After the wood is sliced ​​by a slicer and crushed by a pulverizer, the screened raw materials are transported to the collection bin by a belt conveyor, and then transported to the feed inlet 11 at the top of the tank 1 by a multi-stage screw conveyor mechanism. The speed of the raw material is matched with the rotation speed of the subsequent screw rod 6 to ensure a continuous and stable supply of raw materials.

[0043] Feeding and cooking:

[0044] The process parameters are set, the device is started, and the cooking chamber 8 is preheated. Each group of injection pipes delivers preheated steam to its respective chamber. The drive motor 2 of the double-screw feeding system is started, driving the screw rod 6 to rotate. Subsequently, the raw material enters the steam cylinder 5 inside the preheating chamber 81. The steam diffuses evenly into the raw material through the vent holes of the steam cylinder 5, making full contact with the raw material and initially softening the lignin. The spiral blades of the feeding section 61 propel the loose raw material forward.

[0045] The preheated raw material enters the mixing chamber 82 along with the screw 6. At this time, the screw 6 switches to the cooking section 62, the blade spacing decreases, the raw material is gradually compacted, and at the same time, the steam input is ensured to be greater than that of the preheating chamber 81, so that the steam can penetrate the raw material layer and the lignin in the raw material is fully degraded.

[0046] Steaming and unloading:

[0047] The raw materials that have completed mixing and cooking enter the supplementary steaming chamber 83 along with the screw rod 6. The screw rod 6 switches to the discharge section 63, and the blade spacing decreases again, keeping the raw materials in a compacted state. Steam is introduced into the supplementary steaming chamber 83 by the steam injection mechanism 3 to fill the gaps at the bottom of the raw materials and perform supplementary steaming to ensure that the end fibers are thoroughly cooked.

[0048] After the supplementary steaming is completed, the raw material is pushed to the discharge port 14 by the screw rod 6, and the qualified fibers are discharged and sent to the feed hopper of the thermomill. Before discharge, the temperature sensor installed at the discharge port monitors the fiber temperature in real time to ensure that the temperature meets the preset value. If the temperature does not meet the standard, the speed of the screw rod 6 is automatically reduced and the steaming time is extended until the temperature meets the standard.

[0049] During the above operation, the temperature sensors embedded in the inner wall of the steam cylinder 5 monitor the temperature in each chamber in real time. If the temperature is lower than the preset value, the electric regulating valve will be opened automatically to increase the steam supply.

[0050] The condensate generated during the process flows along the outer wall of the steam cylinder 5 into the collection tank 15 at the bottom of the tank 1. After being filtered by a filter screen to remove fiber debris, it is discharged by an automatic steam trap to prevent condensate from accumulating inside the tank and causing the raw materials to become too wet. It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0051] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. A cooking apparatus for wood fiber production, characterized in that, The system includes a tank (1), a double-helix feeding system, and a zoned steam system. The zoned steam system includes a steam injection mechanism (3) and a steam cylinder (5). The steam injection mechanism (3) is located on both sides of the tank (1). The steam cylinder (5) is coaxially fitted inside the tank (1). The inner wall of the steam cylinder (5) forms a cooking chamber (8). Multiple partition plates (51) are provided between the steam cylinder (5) and the inner wall of the tank (1). The partition plates (51) divide the gap between the steam cylinder (5) and the tank (1) into multiple areas, which correspond to the preheating chamber (81), mixing chamber (82), and supplementary steaming chamber (83) arranged sequentially along the raw material conveying direction of the cooking chamber (8). The double helix feeding system is installed inside the steam cylinder (5). The double helix feeding system includes two parallel helical rods (6). The helical rods (6) are divided into a feeding section (61), a cooking section (62), and a discharging section (63) along the axial direction, which are respectively adapted to the preheating chamber (81), the mixing chamber (82), and the supplementary steaming chamber (83). The steam injection mechanism (3) is independently connected to the preheating chamber (81), the mixing chamber (82), and the supplementary steam chamber (83) through pipelines.

2. The cooking apparatus for wood fiber production according to claim 1, characterized in that, The two ends of the tank (1) are detachably connected to the sealing cap (7), the two ends of the spiral rod (6) are respectively axially connected to the sealing cap (7), and the bottom of the tank (1) is fixedly connected to the support base (4).

3. The cooking apparatus for wood fiber production according to claim 1, characterized in that, The tank (1) includes an insulated shell (12), the top of the insulated shell (12) is provided with a feed inlet (11) corresponding to the preheating chamber (81), and an exhaust pipe (13) is provided corresponding to the supplementary steaming chamber (83). The bottom of the tank (1) is provided with a liquid collection tank (15) and a discharge port (14) corresponding to the supplementary steaming chamber (83).

4. The cooking apparatus for wood fiber production according to claim 1, characterized in that, The steam injection mechanism (3) includes a steam pipe (31) and an injection pipe (32). The steam pipe (31) is arranged along the length of the tank (1). There are 3 sets of injection pipes (32) on each side, corresponding to the preheating chamber (81), the mixing chamber (82), and the supplementary steaming chamber (83), respectively. Each set of injection pipes (32) is equipped with an electric regulating valve, which can independently control the steam pressure and flow rate.

5. The cooking apparatus for wood fiber production according to claim 1, characterized in that, The steam cylinder (5) is made of stainless steel and has densely packed air vents on its surface.

6. The cooking apparatus for wood fiber production according to claim 1, characterized in that, The center distance between the two spiral rods (6) is 1.2-1.5 times the diameter of the spiral rod (6), and the spiral blades rotate in opposite directions. Synchronous reverse rotation is achieved through gear meshing at the ends of the spiral rods (6). One of the spiral rods (6) is connected to the drive motor (2).

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