Wood chip cooking method and device

Abstract

The invention provides a wood board cooking device which comprises a cooking cylinder body, two first steam pipelines used for conveying steam are installed at the bottom of the cooking cylinder body, and three second steam pipelines used for conveying steam are installed on the side wall of the cooking cylinder body. The second steam pipelines on the side wall are located at the two-fifths position above the bottom wall of the cooking cylinder body, and the second steam pipelines on the side wall are evenly distributed on the side wall of the cooking cylinder body. According to the method, the cooking time is shortened, the cooking quality of the wood chips is improved, and fibers are good in shape and white in color after being produced, and are good in appearance and easy to sell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of plate processing, in particular to a wood board steaming method and device. BACKGROUND

[0002] In the wood processing process, wood chip steaming is a key pretreatment process. After the saturated steam is steamed in the steaming cylinder according to the process requirements, the wood chips are sent to the hot mill. The existing wood chip steaming uses three steam pipes installed on the side wall of the steaming cylinder. Steam enters the steaming cylinder from the pipe to steam the wood chips. This equipment has the problems of uneven steaming of wood chips, inconsistent heating of different parts of wood chips, affecting the stability of wood chip quality, and causing wood chips to deform, crack and other problems in subsequent use. SUMMARY

[0003] Therefore, the present application provides a wood chip steaming method and device to solve or alleviate the technical problems in the prior art.

[0004] The technical scheme of the present application is implemented as follows: a wood chip bin, a wood chip plug feed screw, a steaming cylinder body, and a wood chip discharge screw are provided. Six steam pipes, i.e., steam pipe one, steam pipe two, steam pipe three, steam pipe four, steam pipe five, and steam pipe six, are installed on the lower side wall of the steaming cylinder body for transmitting steam. The heights of the six pipes are different by 100 mm in sequence, and the steam pipes are distributed at an angle of 60 degrees. Figure One

[0005] A wood board steaming method is provided, which specifically comprises the following steps:

[0006] Step 1: material selection

[0007] The wood boards are screened to remove defective (e.g., worm-eaten, rotten) wood boards, and then the selected wood boards are classified according to different materials and thicknesses for subsequent adjustment of steam parameters. Then, the dust and impurities on the surface of the classified wood boards are removed to improve the contact effect of steam and wood boards.

[0008] Step 2: pressure boosting and preheating

[0009] The selected wood chips are conveyed to the steaming cylinder body through the wood chip bin lower wood chip plug feed screw, the steam pressure is adjusted to 0.8 MPa, and the steam pressure is stabilized.

[0010] Step 3: continuous controllable steaming

[0011] The rotation speed of the wood chip plug feed screw and the wood chip discharge screw is adjusted to change the stacking height of the wood chips in the steaming cylinder body, thereby changing the steaming time of the wood chips in the steaming cylinder. This can continuously produce qualified steamed wood chips.​

[0012] Step four: discharging

[0013] The cooked wood chips are conveyed to a hot mill by a wood chip discharging screw for grinding and decomposition.

[0014] In the above embodiment step two: the low pressure of steam is 0.2 MPa, and the low temperature is 90 DEG C.

[0015] In the above embodiment step three: the pressure of steam is gradually increased to 0.3-0.5 MPa, and the temperature is gradually increased to 130-150 DEG C.

[0016] In the above embodiment step three: the time in the increased pressure and temperature environment is determined according to the classification of the wood board;

[0017] The multiple temperature sensors and humidity sensors are installed at different positions in the cooking pot body, which can collect the temperature and humidity data in the pot in real time and transmit the data to the control system.

[0018] The control system adopts a PLC controller,

[0019] The present application has the following advantages due to the above technical solutions:

[0020] The six steam pipes installed on the side wall of the cooking cylinder body shorten the cooking time and improve the cooking quality of the wood chips, so that the fibers are in good shape and white color, which is not only good-looking but also easy to sell,

[0021] The process combining preheating with pressure increase avoids excessive heating and long-time high-energy-consumption operation. Meanwhile, the use amount of steam is controlled by the control system without affecting the cooking effect of the wood board, which improves the energy utilization efficiency and reduces the production cost;

[0022] The automatic control of the cooking process is realized by the setting of the PLC controller, which reduces the manual operation, lowers the labor intensity, and improves the production efficiency and the stability of product quality;

[0023] The above summary is only for the purpose of the description and is not intended to limit in any way. In addition to the above described illustrative aspects, embodiments and features, further aspects, embodiments and features will be readily apparent to those skilled in the art by reference to the drawings and the following detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description only only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0025] Figure 1 The overall structure of the cooking cylinder body of the present application is shown in the figure.

[0026] Reference signs:

[0027] 1, cooking cylinder body; 2, steam pipe 1; 3, steam pipe 2. DETAILED DESCRIPTION

[0028] In the following, only some exemplary embodiments are simply described. As those skilled in the art can realize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present application. Therefore, the drawings and the description are considered to be exemplary in nature rather than limiting.

[0029] It should be noted that the terms "first", "second", "symmetric", "array" and the like are only used for distinguishing description and position description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "symmetric" and the like can explicitly or implicitly include one or more of the features; similarly, for some features that are not limited in number by the words "two", "three" and the like, it should be noted that the features also belong to explicitly or implicitly including one or more feature numbers.

[0030] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "fixing" and the like should be understood in a broad sense; for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally formed; it can be mechanically connected, it can be directly connected, it can be welded, it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the description and drawings in combination with specific circumstances.

[0031] The embodiments of the present application will be described in detail below in combination with the drawings.

[0032] In the existing technology, the wood board steaming process generally adopts the bottom single-tube steam input method. Since steam only enters from a single position at the bottom of the cooking cylinder, the steam distribution is obviously uneven. During the cooking process, the heating intensity of the area close to the steam inlet is too high, while the steam penetration in the area far away from the pipe is insufficient, resulting in significant differences in heating of different parts of the wood board. This imbalance in thermal distribution directly affects the stability of the cooking quality, and is prone to material deformation or cracking during subsequent processing.

[0033] In order to solve the above problems, it was found that the traditional single-tube structure could not form a three-dimensional steam circulation path, resulting in obvious blind spots in the steam flow in the cylinder. By analyzing the steam diffusion law, it was realized that increasing the number of steam inlets can improve the uniformity of thermal distribution. Further research found that the spatial layout of the steam input points directly affects the steam coverage range. The reasonable setting of steam channels in different axes can effectively eliminate temperature gradients. Based on this, it is proposed to set up a layered steam pipeline network in the vertical direction and form a composite thermal flow field through multi-dimensional steam injection.

[0034] Therefore, this application proposes a technical solution of setting two steam transmission pipes at the bottom of the cooking cylinder and three steam transmission pipes on the side wall. The side wall pipes are installed at a specific height above the bottom wall of the cylinder and are evenly arranged along the circumference.

[0035] Among them, the steam pipe can be implemented by a circular pipe layout. Three pipes are evenly arranged at 120-degree intervals to form an auxiliary steam diffusion layer. The installation height of the side wall pipe is determined by fluid mechanics calculations and is located at two-fifths of the cylinder height above the bottom wall. This position can avoid flow field interference caused by the direct rise of bottom steam.

[0036] Specifically, the two pipes at the bottom are arranged in parallel to form a basic steam curtain, and the steam diffuses and covers from both sides to the central area. The three pipes on the side walls form a second steam injection layer in the vertical direction, and the steam is evenly injected into the cylinder space radially. The two steam injection layers form a three-dimensional cross steam flow field. During the upward diffusion of the bottom steam, a convection effect is formed with the horizontal flow of the side wall steam. This composite steam distribution pattern effectively eliminates the steam blind spot of the traditional single-tube structure, so that all surfaces of the wooden board can be exposed to the evenly distributed steam flow.

[0037] Compared with the existing technology, the traditional cooking cylinder only relies on a single pipe at the bottom to supply steam. The steam forms a single upward airflow in the vertical direction, and the lateral steam diffusion capacity is limited. This solution builds a three-dimensional steam circulation network through the coordinated work of the two bottom pipes and the three side wall pipes. The two bottom pipes ensure the basic steam supply, and the three side wall pipes make up for the insufficient steam distribution in the vertical direction. The spatial layout of the five pipes forms a steam distribution system covering the entire cylinder volume.

[0038] By the technical scheme, the application realizes three-dimensional uniform distribution of steam in the cooking cylinder, effectively eliminates local overheating or underheating phenomenon, makes the heating intensity of each part of the wood board consistent, makes the internal stress distribution of the material more balanced, significantly reduces the deformation risk in the subsequent processing process, the expansion of the steam coverage area improves the single processing capacity, and reduces the energy waste caused by uneven heating.

[0039] Further, the application provides a wood board cooking method, which comprises four steps of material selection, preheating, pressure increase and cooling. In the material selection stage, the wood board is screened and surface impurities are removed. In the preheating stage, the wood board is placed in a low-pressure and low-temperature steam environment for treatment. In the pressure increase stage, the steam pressure and temperature are gradually increased. In the cooling stage, the wood board is taken out and then ventilated and dehumidified.

[0040] The screening refers to classification according to the appearance quality of the wood board, which can be realized by manual visual inspection or optical detection equipment, and is used to exclude raw materials with defects such as insect damage and decay. The removal of surface impurities refers to the removal of dust and attachments on the surface of the wood board, which can be realized by compressed air blowing or mechanical brushing, so as to ensure that the cooking medium fully contacts the wood. The low-pressure and low-temperature steam environment refers to a state in which the pressure is lower than the conventional cooking pressure and the temperature is lower than the conventional cooking temperature, which can be realized by adjusting the output parameters of the steam generator, and is used to reduce the risk of internal stress mutation of the wood. The gradual increase refers to the stepwise or continuous increase of the pressure and temperature, which can be realized by adjusting the opening degree of the steam valve in stages, so that the wood fibers gradually adapt to the change of heat. The ventilation and dehumidification refer to reducing the moisture content of the wood by air flow, which can be realized by natural air drying or forced convection device, and are used to stabilize the internal structure of the wood.

[0041] Specifically, in the preheating stage, the wood is pretreated by low-pressure and low-temperature steam, so that the wood fibers are preliminarily softened under mild conditions. After the temperature gradient between the surface and the interior of the wood tends to be balanced, the steam parameters are gradually increased, so that the heat gradually penetrates to the core layer of the wood. In this process, the difference in heating rate of each part of the wood is effectively controlled, and fiber damage caused by local overheating is avoided. After cooking, the cooling rate and humidity are controlled to promote uniform water evaporation in the wood.

[0042] Compared with the prior art, the traditional method directly places the wood in a high-temperature and high-pressure environment, which causes the surface fibers to soften too early while the core layer is not sufficiently heated. The present method gradually regulates the steam parameters, so that the wood forms a progressive heat conduction from the outside to the inside, solving the core problem of uneven cooking in the prior art. Compared with the one-step cooking method, this step-by-step treatment effectively avoids wood cracking and deformation.

[0043] By the technical scheme, the wood cooking process is precisely controlled, and the wood boards with different thicknesses can be uniformly heat treated, the mild treatment in the preheating stage reduces the stress concentration in the wood, the gradual change of the parameters in the pressure increasing stage ensures the consistency of the fiber softening, and the humidity control in the cooling stage effectively prevents the later deformation, and the method is particularly suitable for treating the hardwood materials with uneven density, and the cooking efficiency is ensured while the product qualification rate is significantly improved.

[0044] Further, the low pressure of the steam is 0.2 MPa, and the low temperature is 90℃.

[0045] The low pressure means that the steam pressure is lower than the initial pressure of the conventional cooking process, and the steam pipeline inlet pressure can be controlled by a pressure regulating valve, for example, the pressure is stabilized in the range of 0.2 MPa, and the low temperature means that the steam temperature is lower than the initial temperature of the conventional cooking process, and the steam temperature can be adjusted by a temperature sensor and a heating device, for example, the temperature is maintained at 90℃, and the combination of low pressure and low temperature can reduce the instantaneous heat shock of the steam on the wood board and avoid stress concentration caused by too large temperature difference between the surface and the inside.

[0046] Specifically, in the preheating stage, the steam continuously acts on the inside of the cooking cylinder at a pressure of 0.2 MPa and a temperature of 90℃, the low pressure state slows down the steam flow rate, and the low temperature environment prolongs the contact time of the steam and the wood board, so that the steam uniformly penetrates into the fiber gap of the wood board, for example, the pressure regulating device can dynamically control the pipeline pressure in the error range of 0.2 MPa, and the temperature control system maintains the steam temperature stable by adjusting the boiler combustion efficiency, and in this stage, the wood board is slowly heated as a whole by the mild steam condition, and a uniform initial heat distribution is established for the subsequent pressure increasing stage.

[0047] Compared with the prior art, the conventional cooking process often directly uses high-pressure and high-temperature steam for rapid heating, which causes the surface of the wood board to harden too early and the inside to be insufficiently heated, and the present application limits the pressure and temperature parameters in the initial stage to form the basic conditions for gradient heating, so that the steam can gradually penetrate into the deep structure of the wood, thereby improving the cooking uniformity.

[0048] By the technical scheme, the heating difference of the wood board in the preheating stage is effectively reduced, the fiber damage caused by local overheating is reduced, a uniform physical basis is provided for the subsequent pressure increasing cooking, and the size stability and deformation resistance of the finished wood board are improved.

[0049] Further, the pressure of the steam is gradually increased to 0.3-0.5 MPa, and the temperature is gradually increased to 130-150℃.

[0050] The gradual increase in pressure refers to adjusting the steam pressure value in stages, which can be achieved by adjusting the pressure regulating valve in three steps, for example, adjusting to 0.3 MPa for the first time, adjusting to 0.4 MPa for the second time, and adjusting to 0.5 MPa for the third time. This process can avoid internal stress concentration of the wood board due to sudden pressure change. The gradual increase in temperature refers to controlling the temperature rise rate in stages, which can be adjusted by the temperature control system in two stages, for example, the first stage is to raise the temperature to 130°C and maintain for 20 minutes, and the second stage is to raise the temperature to 150°C. This method can prevent cracking caused by excessive temperature difference between the surface and core of the wood board.

[0051] Specifically, in the pressure increasing stage, the steam pressure starts from a low initial pressure and increases in steps, for example, increasing by 0.1 MPa each time and maintaining for 10 minutes, while the temperature is also proportionally increased. Through the coordinated control of pressure and temperature, the steam can gradually penetrate into the fiber structure of the wood board, making the lignin soften uniformly. In this process, steam pipes one and two input steam from different positions at the bottom and side wall respectively, forming a three-dimensional heat exchange environment, further ensuring the uniformity of cooking.

[0052] Compared with the prior art, the traditional cooking process uses a single pressure and temperature increasing method, which causes uneven distribution of steam in the cooking cylinder, easily leading to excessive or insufficient heating of the wood board. The present application adjusts the pressure and temperature parameters in stages and combines a multi-directional steam input structure to make the steam diffusion path more consistent with the wood fiber direction, thereby improving the heat conduction efficiency.

[0053] Through the above technical solution, the present application can effectively solve the problem of internal structure damage caused by sudden change of temperature and pressure during the cooking process of the wood board, and make the wood fiber gradually soften in a controllable environment, thereby improving the mechanical stability of the cooked wood board and reducing the occurrence of deformation or cracking in subsequent processing.

[0054] Further, the present application proposes to determine the time in the improved pressure and temperature environment according to the classification of the wood board.

[0055] The classification of the wood board refers to the classification according to the type, density or moisture content of the wood, which can be realized by measuring the physical properties of the wood by a detection instrument, for example, grouping the wood by using a density meter or a moisture content tester. This classification is used to match different cooking parameters to solve the problem of uneven heating caused by the difference in wood characteristics. The time in the pressure and temperature environment refers to the total time of the steam treatment stage, which can be realized by setting different time parameters by a controller, for example, automatically adjusting the pressure holding time in the cooking cylinder according to the wood classification result. This parameter control can avoid the over-treatment or under-treatment phenomenon caused by uniform cooking time.

[0056] Specifically, after the pressure temperature is raised in the pressure raising stage, the hard wood material can be set with a longer pressure holding time to ensure that the steam fully penetrates the wood fiber, while the soft wood material is set with a shorter pressure holding time to prevent over-softening, for example, the wood with a density higher than 0.6 g / cm 3 The processing time can be extended to 60 minutes for the wood with a density lower than 0.4 g / cm 3 Thus, the steam is uniformly applied to different parts of the wood board in the digester.

[0057] Compared with the prior art, the conventional cooking method adopts a fixed processing time for all wood materials without considering the difference in material properties, which can easily cause the core layer and the surface layer of the wood board to be heated inconsistently. The present application matches the time parameters according to the classification, so that the steam action time is adapted to the heat absorption rate of the wood material, and the uneven cooking phenomenon caused by the difference in heat absorption of the material is eliminated.

[0058] Through the above technical solution, the present application solves the problem of inconsistent heating of different parts of the wood board in the cooking process, so that the steam can fully penetrate the internal structure according to the properties of the wood material, and the cooking uniformity is improved, thereby avoiding deformation or cracking defects caused by uneven internal stress in subsequent processing.

[0059] Further, the present application proposes to determine the time in the improved pressure and temperature environment according to the classification of the wood board.

[0060] The classification of the wood board refers to the classification of the wood material according to the material properties or physical parameters, which can be realized by using a wood density detector or a tree species recognition device. The corresponding relationship of different cooking parameters is established through classification, and the time in the pressure and temperature environment refers to the duration of continuous cooking after the steam pressure is raised to 0.3-0.5 MPa and the temperature is raised to 130-150℃. The time gradient can be set by a programmable controller, and dynamic adjustment can be made in combination with real-time feedback of the pressure sensor and the temperature sensor.

[0061] Specifically, after the pressure and temperature are raised in the pressure raising stage, the cooking time is automatically matched according to the classification of the wood material. For example, the high-density hard wood board can be set with a longer cooking time, and the low-density soft wood board can be set with a shorter cooking time. The steam in the digester is uniformly distributed through the two bottom pipes and the three side wall pipes, and the dynamic control of the time parameter enables different types of wood to complete the cooking under the best working conditions.

[0062] Compared with the prior art, the existing cooking process adopts a fixed time parameter, which cannot adapt to the difference in heat absorption characteristics of different wood materials. The present application solves the problem of uneven distribution of internal stress of the wood material caused by improper cooking time through classification and matching of time parameters.

[0063] By the technical solution, the cooking time in the high-temperature and high-pressure stage can be accurately controlled according to the fiber structure and density characteristics of different wood materials, so that the over-decomposition of lignin caused by over-cooking or the residual internal stress caused by insufficient cooking is avoided, and the dimensional stability and deformation resistance of the wood board product in subsequent processing are improved.

[0064] Further, the application provides a method for determining the time in the improved pressure and temperature environment according to the classification of the wood board.

[0065] The classification of the wood board refers to grouping according to the differences in material density, thickness or moisture content, which can be realized by an optical sorting instrument or a mechanical thickness measuring device. Different categories of wood boards have different fiber structure characteristics. The time in the pressure and temperature environment refers to the duration of the continuous action after the steam parameters reach the target range. The PLC control system can preset the process curve corresponding to different wood materials, and the pressure sensor and thermocouple can feed back data in real time to trigger the timing module.

[0066] Specifically, after the steam pressure is increased to 0.3-0.5 MPa and the temperature reaches 130-150℃, a 60-minute cooking program is started for hardwood boards, and a 40-minute process is performed for softwood boards. During the cooking process, the control system automatically matches the corresponding parameter combination according to the initial set wood type code. When it is detected that the actual pressure value in the cooking cylinder deviates from the target range by more than 5%, the regulating valve performs dynamic compensation to maintain process stability.

[0067] Compared with the prior art, the traditional cooking process uses a fixed time for all wood materials, which can easily lead to insufficient cooking of hard wood with high density or over-softening of soft wood with loose texture. The present application establishes a classification processing mechanism to precisely process wood boards of different materials such as basswood and pine under steam parameters matching their fiber characteristics.

[0068] By the technical solution, the application effectively avoids the uneven distribution of internal stress in the wood board caused by mismatching of cooking time and material characteristics, reduces the surface warping or end cracking defects in the subsequent processing process, and makes the moisture content gradient of the cooked wood board more consistent with the requirements of the hot-pressing forming process.

[0069] Further, the application provides a method for determining the cooking time in the improved pressure and temperature environment according to the classification of the wood board.

[0070] The classification of the wood board refers to the classification according to the wood species, density or thickness, and can be realized by manual sorting or automatic detection equipment. Different types of wood boards need to match different cooking parameters due to internal structure differences. The time in the pressure and temperature environment refers to the duration of continuous cooking when the steam pressure is 0.3-0.5 MPa and the temperature is 130-150°C. The specific time parameters can be set by a programmable controller, for example, the cooking time is extended for hardwood boards, and the cooking time is shortened for thin boards.

[0071] Specifically, after the pressure and temperature are raised in the pressure raising stage, the steam parameters in the cooking cylinder reach a stable state. At this time, the corresponding time parameters are automatically called according to the pre-set classification standard. For example, for high-density hardwood boards, the cooking time is extended to more than 60 minutes, and for low-density pine boards, the time is shortened to within 40 minutes. Thus, different types of wood boards are subjected to differentiated cooking under the same pressure and temperature conditions, avoiding internal stress differences caused by insufficient or excessive cooking.

[0072] Compared with the prior art, the existing cooking process uses fixed cooking time for all boards without considering the differences in wood species and physical properties, resulting in uneven heating of some boards. The present scheme matches the time parameters by classification, so that the steam energy can fully penetrate into the interior of the boards with different structural characteristics, solving the problem of uneven heating caused by material differences.

[0073] Through the above technical scheme, the present application can dynamically adjust the cooking time according to the characteristics of different wood materials, so that the steam forms a uniform heat conduction path in the board, thereby reducing the moisture content difference of the board after cooking and avoiding deformation or cracking caused by local stress concentration in subsequent processing.

[0074] Further, the present application proposes a wood board cooking method, which comprises determining the time in the improved pressure and temperature environment according to the classification of the wood board.

[0075] The classification of the wood board refers to the classification according to the wood species, density or thickness, and can be realized by manual sorting or automatic detection equipment. Different types of wood boards need to match different cooking parameters due to internal structure differences. The time in the pressure and temperature environment refers to the duration of continuous cooking when the steam pressure is 0.3-0.5 MPa and the temperature is 130-150°C. The specific time parameters can be set by a programmable controller, for example, the cooking time is extended for hardwood boards, and the cooking time is shortened for thin boards.

[0076] Specifically, after the gradual increase of the steam pressure and temperature is completed, different processing times are set for different types of wood boards, for example, for high-density hardwood wood boards, the processing time in the high-pressure and high-temperature environment can be extended to make them fully absorb heat and soften the wood fibers; and for softwood wood boards with thin thickness, the processing time is shortened to prevent over-cooking. During the processing, the temperature and humidity parameters in the cooking cylinder can be monitored in real time, and the time parameters can be automatically adjusted in combination with the preset wood property database to ensure the consistency of the cooking effect.

[0077] In some embodiments, the correspondence between the classification and the time can be achieved by a preset process parameter table, for example, the wood boards are divided into three groups according to the thickness, the group with a thickness greater than 50 mm corresponds to a processing time of 60 minutes, the group with a thickness between 30 and 50 mm corresponds to a processing time of 50 minutes, and the group with a thickness less than 30 mm corresponds to a processing time of 40 minutes. In addition, the processing time can be further subdivided according to the moisture content of the wood or the fiber direction.

[0078] Compared with the prior art, the existing cooking method uses a fixed processing time and does not consider the differences in the heat conduction characteristics of different wood boards, resulting in uneven heating of some wood boards. The present scheme matches the time parameters by classification, so that high-density or thick-section wood boards can obtain more sufficient cooking, while low-density or thin-section wood boards are prevented from being structurally damaged due to too long processing time, thereby improving the cooking uniformity at the root.

[0079] Through the above technical scheme, the present application solves the problem of inconsistent heating of wood boards caused by fixed cooking time in the prior art, so that different types of wood boards can all obtain a heat treatment process adapted to their physical properties, effectively reducing the occurrence of deformation or cracking in subsequent processing, and optimizing the energy utilization efficiency.

[0080] Further, the present application proposes to determine the time in the improved pressure and temperature environment according to the classification of the wood board.

[0081] The classification of the wood board refers to the classification of the wood board according to the material type, thickness specification or density grade, which can be realized by using a tree species detector, a thickness measuring instrument or a densimeter, etc. Through classification, corresponding cooking parameters can be matched for wood boards with different physical properties. The time in the pressure and temperature environment refers to the duration of the wood board in the improved steam pressure and temperature environment, which can be realized by the linkage control of the pressure sensor, the temperature sensor and the timer. The duration directly affects the softening degree of the wood board internal fibers.

[0082] Specifically, after the pressure and temperature are raised in the pressure raising stage, the cooking duration of the corresponding category is automatically matched according to the pre-established wood board classification database, for example, the pine wood board is kept for 55 minutes under the condition of 0.4 MPa pressure and 140 DEG C, while the hardwood board is kept for 65 minutes under the same condition, and the pressure and temperature data are monitored in real time during the cooking process, and the cooling process is started immediately when the set time is reached.

[0083] Compared with the prior art, the existing cooking process adopts a unified cooking time for all wood boards, without considering the differences in heat absorption rate and fiber structure of different materials, resulting in insufficient heating or over-cooking of part of the wood boards, and the present application matches the time parameters by classification, so that the hardwood with high density obtains a longer heat conduction time, and the softwood with loose texture avoids loose structure caused by too long cooking time.

[0084] Through the above technical solution, the present application solves the problem of uneven heating of wood boards caused by single cooking time, so that different categories of wood boards achieve uniform softening effect under their respective adapted cooking time, effectively reducing the risk of deformation or cracking caused by inconsistent fiber softening degree in subsequent processing.

[0085] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of various changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A wood board cooking device, comprising a cooking cylinder body (1), characterized in that: Two steam pipes (2) for transmitting steam are installed at the bottom of the cooking cylinder body (1), and three steam pipes (3) for transmitting steam are installed on the side wall of the cooking cylinder body (1). The steam pipes (2) on the side wall are located at two-fifths above the bottom wall of the cooking cylinder body (1), and the steam pipes (2) on the side wall are evenly distributed on the side wall of the cooking cylinder body (1).

2. A wood board cooking method according to claim 1, characterized in that: Step 1: Material selection The wood chips are screened to remove defective boards (such as those that are insect-eaten or rotten), and then the dust and impurities on the surface of the separated boards are cleared. Step 2: Boost and preheat The selected good wood chips are conveyed into the cooking cylinder through the wood chip plug feeding screw at the bottom of the wood chip bin, and then the steam pressure is adjusted to 0.8Mpa and stabilized. Step 3: Continuous Controlled Cooking By adjusting the rotation speed of the chip and plug feeding screw and the chip discharging screw, the stacking height of the chips in the cooking cylinder can be changed, thereby changing the length of the cooking time of the chips in the cooking cylinder, so that qualified cooking chips can be continuously produced. Step 4: Discharging The cooked wood chips are transported to the hot grinder through the wood chip discharging spiral for grinding and decomposition.

3. A wood chip cooking method according to claim 2, characterized in that: The low pressure of steam is 0.2MPa and the low temperature is 90℃.

4. A wood chip cooking method according to claim 3, characterized in that: The steam pressure is gradually increased to 0.5MPa-0.8MPa, and the temperature is gradually increased to 150℃-180℃.

5. A wood chip cooking method according to claim 4, characterized in that: The time spent in the elevated pressure and temperature environment is determined by the classification of the wood chips.

Images