AU2020103153A4 - Method for improving wood permeability - Google Patents
Method for improving wood permeability Download PDFInfo
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- AU2020103153A4 AU2020103153A4 AU2020103153A AU2020103153A AU2020103153A4 AU 2020103153 A4 AU2020103153 A4 AU 2020103153A4 AU 2020103153 A AU2020103153 A AU 2020103153A AU 2020103153 A AU2020103153 A AU 2020103153A AU 2020103153 A4 AU2020103153 A4 AU 2020103153A4
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- Australia
- Prior art keywords
- wood
- test piece
- microwave
- microwave treatment
- temperature
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- 239000002023 wood Substances 0.000 title claims abstract description 185
- 238000000034 method Methods 0.000 title claims abstract description 28
- 230000035699 permeability Effects 0.000 title claims abstract description 26
- 238000012360 testing method Methods 0.000 claims abstract description 228
- 238000010438 heat treatment Methods 0.000 claims abstract description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 13
- 238000001035 drying Methods 0.000 claims description 12
- 238000009835 boiling Methods 0.000 claims description 4
- 238000005485 electric heating Methods 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 2
- 229910052755 nonmetal Inorganic materials 0.000 claims description 2
- 230000008569 process Effects 0.000 abstract description 11
- 230000000694 effects Effects 0.000 abstract description 10
- 238000012545 processing Methods 0.000 abstract description 5
- 238000005470 impregnation Methods 0.000 description 16
- 235000019786 weight gain Nutrition 0.000 description 10
- 230000004584 weight gain Effects 0.000 description 10
- 239000007788 liquid Substances 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 4
- 239000002274 desiccant Substances 0.000 description 4
- 230000007547 defect Effects 0.000 description 3
- WSFSSNUMVMOOMR-UHFFFAOYSA-N formaldehyde Substances O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 230000005855 radiation Effects 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 244000137852 Petrea volubilis Species 0.000 description 2
- 241000219000 Populus Species 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 235000021053 average weight gain Nutrition 0.000 description 2
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 2
- 239000012153 distilled water Substances 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 238000009834 vaporization Methods 0.000 description 2
- 230000008016 vaporization Effects 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 239000004480 active ingredient Substances 0.000 description 1
- 239000013068 control sample Substances 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
- B27K5/00—Treating of wood not provided for in groups B27K1/00, B27K3/00
- B27K5/003—Treating of wood not provided for in groups B27K1/00, B27K3/00 by using electromagnetic radiation or mechanical waves
- B27K5/0055—Radio-waves, e.g. microwaves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
- B27K5/00—Treating of wood not provided for in groups B27K1/00, B27K3/00
- B27K5/001—Heating
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B3/00—Drying solid materials or objects by processes involving the application of heat
- F26B3/32—Drying solid materials or objects by processes involving the application of heat by development of heat within the materials or objects to be dried, e.g. by fermentation or other microbiological action
- F26B3/34—Drying solid materials or objects by processes involving the application of heat by development of heat within the materials or objects to be dried, e.g. by fermentation or other microbiological action by using electrical effects
- F26B3/347—Electromagnetic heating, e.g. induction heating or heating using microwave energy
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Mechanical Engineering (AREA)
- Wood Science & Technology (AREA)
- Forests & Forestry (AREA)
- Chemical And Physical Treatments For Wood And The Like (AREA)
Abstract
The invention discloses a method for improving wood permeability, which comprises the
following steps of: processing wood in a microwave processing mode, and preheating the
bottom of a resonant cavity of microwave pretreatment equipment in order to carry out
microwave processing on the wood at a certain preset temperature. Aiming at the problem that
the difference of the heating rate of each wood test piece in the microwave pretreatment process
causes great difference in the improving degree of the permeability effect of each wood test
piece after the microwave treatment, the invention adopts the steps of preheating the bottom of
a resonant cavity of microwave pretreatment equipment, controlling the heating rate while
carrying out the microwave treatment on the wood test piece up to the pre-test temperature,
and strictly controlling the time interval of the microwave treatment on the test piece before
and after microwave treatment to control and reduce the difference in the heating rate of each
wood test piece in the subsequent microwave treatment process and then minimum the
difference of the improving degree of the permeability effect of each wood test piece after the
microwave treatment.
Description
Method for improving wood permeability
The invention relates to a method for improving wood permeability and belongs to the technical field of wood modification.
In the process of modifying the wood impregnation, there are problems of small depth of the active ingredients in the impregnating compound entering the wood, low distribution uniformity and low drug loading ration on wood.
The high-intensity microwave can rapidly warm up and vaporize water in the wood, and the vapor pressure in the cells is increased accordingly, as a result, cracks of different degrees are generated in the microstructure of the wood, a new fluid channel is formed in the wood, and the permeability of the wood is improved.
The method for improving the permeability of the wood by adopting the microwave pretreatment has the characteristic of short treatment time, and the greater the microwave power is, the better the effect of improving the permeability of the wood is.
In the process of carrying out microwave pretreatment on the wood, even if the shape, size, wood type, moisture content and microwave power of the wood test pieces are the same, there is still huge difference in the heating rate of the wood. The heating rate of the wood will greatly affect the vapor pressure in the cells, thereby affecting the improvement effect of the permeability of the wood.
In order to overcome the defects of the prior art, the invention provides a method for improving the permeability of wood.
The technical scheme adopted by the invention is as follows:
The invention relates to a method for improving wood permeability, which adopts a microwave treatment mode to treat wood, and is characterized in that the bottom of a resonant cavity of microwave pretreatment equipment is preheated, so that the wood is subjected to microwave treatment at a certain preset temperature.
Preferably, the method comprises the following steps of:
(1) Preparing wood test pieces with basically same materials, shapes and sizes, and adjusting the moisture content of the wood test piece to ensure that the moisture content of the wood test pieces is basically the same;
(2) Preheating the bottom of a resonant cavity of the microwave pretreatment equipment;
(3) Adopting microwave pretreatment equipment to carry out pre-test treatment on wood test pieces so as to obtain a proper microwave treatment temperature;
(4) Adopting microwave pretreatment equipment to carry out microwave treatment on the wood test piece at the microwave treatment temperature obtained in Step (3), and then drying the wood test piece via an oven.
Preferably, in Step (1), the moisture content is controlled to be a certain value within the range of 10%-26%, and the moisture content error between the same batches of test pieces is ±2. For example, when the moisture content of the test pieces in the batch is controlled to be 15%, all wood test pieces with 14-16% moisture content are qualified.
Preferably, for the microwave pretreatment equipment without an electric heater at the bottom in Step (2), the preheating mode is as follows: place a non-metal container filled with water in the center of the bottom of the resonant cavity, with the bottom of the container fully contacted with the bottom of the resonant cavity and the shape and the size of the container larger than or equal to that of wood test pieces, heat the water via microwave heating until the water is just boiling, take it out; and for the microwave pretreatment equipment with an electric heater at the bottom, warm up the temperature at the bottom of the resonant cavity to a certain preset temperature via a bottom electric heating mode, carry out Step (3) after the temperature is kept stable for 10 minutes, and maintain the electric heating at the bottom in the subsequent steps.
Preferably, in Step (3), place the wood test piece up to the pre-test temperature in the center of the bottom of the resonant cavity for microwave treatment, carry out microwave treatment, warm up the temperature of the test piece at least to the preset temperature, end the microwave treatment on the wood test piece, take out the wood test piece, record the time for the microwave treatment on the wood test piece, then put in next wood test piece up to the pre-test temperature, carry out microwave treatment on the second and following wood test pieces up to the pre-test temperature with the microwave treatment time corresponding to the preset temperature, and repeat this step until the temperatures of the microwave treatment on the wood test piece are basically the same, i. e. the heating rate of wood test pieces is relatively stable; wherein, the duration from taking out the last wood test piece and putting in next wood test piece is a fixed value, with the error no more than 0.5s.
The preheating and pretreatment processes are used for keeping the heating rate of the subsequent wood test pieces stable.
Preferably, in Step (4), place the wood test piece in the center of the bottom of the resonant cavity for microwave treatment, the microwave treatment time equals to the microwave treatment time corresponding to the preset temperature, end the microwave treatment on the wood test piece, take out the wood test piece, put in the next wood test piece, repeat this step until all the wood test pieces are treated, wherein, the duration from taking out the last wood test piece and putting in next wood test piece is a fixed value, with the error no more than 0.5s.
Preferably, put the wood test piece subjected to microwave treatment into an oven at 60 °C and dry it until the moisture content is less than 10%, and then the raise the oven temperature up to 103 °C until the wood test piece is completely dried.
Preferably, the microwave frequency of the microwave pretreatment device is 915 MHz-2,450 MHz.
The invention has the advantages that:
(1) Aiming at the problems that it's difficult for the effective components of the impregnating compound fully entering the interior of the wood, and the effective components of the impregnating compound are not uniformly distributed in the interior of the wood during the process of modifying the wood impregnation, the microwave pretreatment on the wood can result in the generation of a large amount of macroscopic and microscopic cracks in the wood, rapidly improve the permeability of wood test pieces in a short time, make the effective components in the impregnating compound entering the interior of the wood in a easier way and being distributed in a more uniform manner, and release the internal stress at the same time.
(2) Aiming at the problem that the large difference in the heating rate of each wood test piece during the microwave pretreatment process causes the great difference in the permeability effect improvement degree of each wood test piece after the microwave treatment (in particular to the wood test piece with small thickness), the invention adopts the steps of preheating the bottom of a resonant cavity of microwave pretreatment equipment, observing the heating rate while carrying out the microwave treatment on the wood test piece up to the pre-test temperature, and strictly controlling the time interval of the microwave treatment on the test piece before and after microwave to control and minimum the difference of the heating rate of each wood test piece in the subsequent microwave treatment process, and minimum the difference of the permeability effect improvement degree of each wood test piece after the microwave treatment.
(3) The method for improving the permeability of the wood by microwave treatment has the characteristics of short time and high efficiency.
Embodiment 1:
(1) The wood test piece is a poplar veneer with the size of 100 mm in length, 100 mm in width and 2 mm in thickness, the surface is clean and smooth, free from nodes, cracks or any other defects. Polish the wood test piece simply with 320 mesh sand paper to remove surface burrs, and blow off surface debris with an ear-washing ball.
(2) Place the wood test piece into a constant temperature and humidity chamber with the setting temperature of 25°C and the relative humidity of 60% for 48 hours to control the moisture content of the test piece to be 10% to 13%.
(3) The microwave frequency of the microwave pretreatment equipment is 2,450 MHz, the output power of the microwave source is 800 w, the size of the resonant cavity is 320 mmx315 mmx210 mm, the volume power of the microwave is 37.8 kW/m3 , and the microwave pretreatment equipment has no bottom electric heater.
(4) Classify the wood test pieces into three groups: A, B and C.
(5) Carry out microwave treatment on Group A wood test pieces: place the wood test pieces in the center of the bottom of the resonant cavity of the microwave pretreatment equipment, end the microwave treatment on the test pieces for 50 s, take out the wood test pieces, put in next wood test pieces up to the pre-test temperature for the microwave treatment, and record the duration taken for the microwave treatment on each wood test piece and the target temperature.(the wood test pieces should be placed at the same position during each microwave treatment, and only one wood test piece is subjected to microwave treatment at one time. and the time interval from the completion of the microwave treatment on the previous wood test piece to the start of the microwave treatment on the next wood test piece is not strictly controlled.) After microwave treatment for 50 s, the average temperature should be 129.0 °C, the range should be 26.7 °C, and the standard deviation should be 7.980 °C.
(6) Carry out microwave treatment on Group B wood test pieces: add 250 ml water into a beaker with the bottom diameter larger than 150 mm, put the beaker into the center of the bottom of a resonant cavity of the microwave pretreatment device, carry out microwave treatment until the water is exactly boiling, take out the beaker, quickly place the wood test piece up to the pre-test temperature in the center of the bottom of the resonant cavity of the microwave pretreatment equipment, finish microwave radiation after the temperature of the microwave treatment on test piece is higher than 135 °C, quickly take out the wood test piece up to the pre-test temperature, place next wood test piece up to the pre-test temperature, with the placing position being the same as that of the previous test piece, and carry out microwave treatment. When the temperature of the test piece up to pre-test temperature reaches 132 °C-138 °C and maintains stable in this interval upon 50s microwave treatment, carry out the formal test (test approximately 4-6 test pieces, and after the time interval from the completion of the microwave treatment on the previous wood test piece to the start of the microwave treatment on the next wood test piece is controlled within 2-3s, the test piece up to the pre-test temperature can reach the condition). Place the wood test piece horizontally in the center of the bottom of a resonant cavity of microwave pretreatment equipment, end the microwave treatment on the wood test piece when the temperature of the test piece increases to 132 °C-138 °C upon 50 s microwave treatment, quickly take out wood test pieces, put in next wood test pieces up to the pre-test temperature for the microwave treatment, record the time taken for microwave treatment on each wood test piece and the temperature reached by the test piece.(the wood test pieces should be placed at the same position during each microwave treatment, and only one wood test piece is subjected to microwave treatment at one time, and the test pieces up to the pre-test temperature are not counted into the following data statistics). After microwave treatment for 50 s, the average temperature of test pieces should be 135.5 °C, the range should be 6 °C, and the standard deviation should be 2.225 °C.
(7) Take Group C wood test pieces as the control sample and are not subjected to microwave treatment.
(8) Put Group A, B and C test pieces into an oven at the temperature of 60 °C for drying until the moisture content is less than 10%, and raise the oven temperature up to 103 °C until the wood test piece is completely dried; put the test piece into a dryer containing a drying agent to fully cool down to the normal temperature, weigh the mass of the test piece and record it (in gram, and is accurate to 3 digits after decimal point).
(9) Stack the dried three groups of wood test pieces in a vacuum impregnation tank in order, with gaps left among the wood test pieces, and press the tops of the three groups of wood test pieces by using a heavy object.
(10) Prepare a 20% PEG2000 aqueous solution as an impregnation liquid, and inject the impregnation liquid into the vacuum impregnation tank until the liquid level is about 2 cm above the top of the test piece, and carry out vacuum-atmospheric impregnation, with the vacuum time being 60 min, the vacuum degree being-0.1 MPa, and the normal pressure impregnation time being min.
(11) Take out the wood test piece, simply wash the surface with distilled water, remove excessive moisture on the surface with paper towels, put the wood test piece into a 60 °C constant temperature drying oven for drying for 3 hours, raise the temperature of the drying oven to 103 °C for drying for 2 hours until the wood test piece is completely dried.
(12) Place the impregnated and dried wood test piece into a dryer filled with a drying agent to fully cool to the normal temperature, weigh the mass of the test piece and record it (in gram, and is accurate to 3 digits after decimal point), calculate the weight gain rate of the wood test piece. After putting the test piece into vacuum-atmospheric impregnation with 20% PEG2000 in the same process, the weight gain rate of the three groups of test pieces is counted as shown in Table 1. Compared with Group A test pieces, the average weight gain rate of Group B test pieces which are preheated by a resonant cavity and are up to the pre-test temperature in the microwave pretreatment process is increased higher, and the variance and the range of the weight gain rate are effectively reduced.
Table 1 Statistics of Weight Gain Rates for Three Groups of Test Pieces
Average weight Variance of Range of weight Multiples of average gain rate (%) weight gain rate gain rate (%) weight gain rate relative (%) to Group C
Group A 33.09 4.39 11.76 1.24
Group B 38.24 2.03 5.93 1.43
Group C 26.78 2.37 6.64 1
In the embodiment, Group A test pieces are not preheated by the resonant cavity, so that the heating rate is slower than that of Group B; steam expansion power generated in the wood by evaporation and vaporization of moisture in the wood is weaker, there are less micro cracks generated in the wood, and the effect of improving the permeability of the wood is less than that of Group B.
Without undergoing pre-test temperature on Group A and no control on the time interval of microwave treatment on test pieces before and after microwave treatment, when each test piece is placed into the resonant cavity, the residual temperature left at the bottom of the resonant cavity is different. As a result, the heating rate of the test pieces in the same group varies largely, and the effect of improving the wood permeability also varies greatly.
Embodiment 2:
(1) The wood test piece is a poplar veneer with the size of 100 mm in length, 100 mm in width and 2mm in thickness, the surface is clean and smooth, free from nodes, cracks or any other defects. Polish the wood test piece simply with 320 mesh sand paper to remove surface burrs, and blow off surface debris with an ear-washing ball.(2) Place the wood test piece into a constant temperature and humidity chamber with the setting temperature of 25 °C and the relative humidity of 60% for 48 hours to control the moisture content of the test piece to be 10% to 13%.
(3) The microwave frequency of microwave pretreatment equipment is 2,450 MHz, the power of microwave source is 850 w, the size of resonant cavity is 300 mmx300 mmx300 mm, the volume power of microwave is 31 kW/m 3 , and there is no bottom electric heater.
(4) Add 250 ml water into a beaker with the bottom diameter larger than 150 mm, put the beaker into the center of the bottom of a resonant cavity of the microwave pretreatment device, carry out microwave treatment until the water is exactly boiling, take out the beaker, quickly place the wood test piece up to the pre-test temperature in the center of the bottom of the resonant cavity of the microwave pretreatment equipment, finish microwave radiation after the temperature of the microwave treatment on test piece is higher than 135 °C, quickly take out the wood test piece up to the pre-test temperature, place next wood test piece up to the pre-test temperature, with the placing position being the same as that of the previous test piece, and carry out microwave treatment. When the temperature of the test piece up to pre-test temperature reaches 132 °C-138 °C and maintains stable in this interval upon 50 s microwave treatment, carry out the formal test. Place the wood test piece horizontally in the center of the bottom of a resonant cavity of microwave pretreatment equipment, end the microwave treatment on the wood test piece when the temperature of the test piece increases to 132 °C-138 °C upon 50 s microwave treatment, quickly take out wood test pieces, put in next wood test pieces up to the pre-test temperature for the microwave treatment, record the time taken for microwave treatment on each wood test piece and the temperature reached by the test piece.(the wood test pieces should be placed at the same position during each microwave treatment, and only one wood test piece is subjected to microwave treatment at one time, and the test pieces up to the pre-test temperature are not counted into the following data statistics).
(5) Discard the used wood test pieces up to the pre-test temperature, put the other wood test pieces subjected to microwave treatment and the wood test pieces in the control group which are not subjected to microwave treatment into an oven at the temperature of 60 °C, dry them until the moisture content is less than 10%, and raise the temperature of the oven to 103 °C until the wood test pieces are absolutely dried; put the test piece into a dryer containing a drying agent, fully cool the test piece to the normal temperature, weigh the mass of the test piece and record it (in gram, and is accurate to 3 digits after decimal point).
(6) Stack the dried wood test pieces and the wood test pieces in the control group subjected to microwave treatment in a vacuum impregnation tank in order, with gaps left among the wood test pieces, and press the tops by using a heavy object.
(7) Prepare a 20% melamino-formaldehyde resin aqueous solution as an impregnation liquid, and inject the impregnation liquid into the vacuum impregnation tank until the liquid level is about
2 cm above the top of the test piece, and carry out vacuum-atmospheric impregnation, with the vacuum time being 60 min, the vacuum degree being-0.1 MPa, and the normal pressure impregnation time being 90 min.
(8) Take out the wood test piece, simply wash the surface with distilled water, remove excessive moisture on the surface with paper towels, put the wood test piece into a 60 °C constant temperature drying oven for drying for 3 hours, raise the temperature of the drying oven to 103 °C for drying for 2 hours until the melamino-formaldehyde resin in the wood test piece is completely solidified and dried.
Place the impregnated and dried wood test piece into a dryer filled with a drying agent to fully cool to the normal temperature, weigh the mass of the test piece and record it (in gram, and is accurate to 3 digits after decimal point), calculate the weight gain rate of the wood test piece. After putting the test piece into vacuum-atmospheric impregnation with 20% melamino-formaldehyde resin in the same process, the weight gain rate of wood test pieces subjected to microwave treatment is 1.40 times of wood test pieces in the control group not subjected to microwave treatment.
Determination of a certain preset temperature and microwave pretreatment time corresponding to the preset temperature:
1. Selection of microwave power
Theoretically, the faster the heating rate of the test piece is, the stronger the steam expansion power generated in the wood by evaporation and vaporization of moisture in the wood is. As a result, there are more microscopic cracks generated in the wood, and the effect of improving the permeability of the wood is better. Therefore, the maximum output power which can be achieved by microwave pretreatment equipment is generally selected for the microwave power (or the microwave intensity) to achieve the best effect. However, when the method is adopted at lower output power, the heating rate of each wood test piece can be basically stable; and finally, the weight gain rate of the impregnated wood test piece is within a certain range.
2. Selection of microwave radiation time and preset temperature
Under the set microwave output power, the microwave time can be selected every 10s from Os (if the microwave output power is large, the time interval value can be shortened as required). Each group of wood test pieces shall be preheated by a resonant cavity before the formal start of the experiment, and the time interval from the completion of microwave treatment of the previous wood test piece (or test pieces up to the pre-test temperature) to the start of microwave treatment of the next wood test piece (or test pieces up to the pre-test temperature) is a fixed value, with the error being 0.5 s, and the fixed value of the time interval should be as short as possible.
Before a formal test begins, a test piece up to the pre-test temperature shall be tested firstly, and the test piece is treated according to the required microwave output power and the microwave treatment time condition of the corresponding group. When the temperature of the test pieces up to the pre-test temperature under the microwave output power and the microwave treatment time condition of the group is relatively stable, the formal test is started again, and the temperature reached by the test piece during the formal test is recorded.
Test the weight gain rate after drying the processed test pieces, and after eliminating abnormal data, set the average value of the temperature reached by a group of test pieces with the largest average weight gain rat as the optimal preset temperature, and set the error of the preset temperature to be 0.5* (range+1). The microwave processing time of the group of test pieces is the microwave processing time corresponding to the preset temperature. In Embodiment 1, the optimum preset temperature is 135.5 3.5 °C.
Claims (7)
1. The invention relates to a method for improving wood permeability, which adopts a microwave treatment mode to treat wood, and is characterized in that the bottom of a resonant cavity of microwave pretreatment equipment is preheated, so that the wood is subjected to microwave treatment at a certain preset temperature.
2. The method for improving wood permeability according to Claim 1, comprising the steps of:
(1) Preparing a wood test piece with basically same materials, shapes and sizes, and adjusting the moisture content of the wood test piece to ensure that the moisture content of the wood test piece is basically consistent;
(2) Preheating the bottom of a resonant cavity of the microwave pretreatment equipment;
(3) Adopting the microwave pretreatment equipment to carry out pre-test treatment on the wood test piece until the heating rate of the wood test piece is basically stable;
(4) Adopting the microwave pretreatment equipment to carry out microwave treatment on the wood test piece at the microwave treatment temperature obtained in Step (3), and then drying the wood test piece via an oven.
3. The method for improving wood permeability according to Claim 2, which is characterized in that in Step (1), the moisture content is controlled to a certain value within a range of 10% to 26%, and the moisture content error between the same batch of test pieces is 1.
4. The method for improving wood permeability according to Claim 3, which is characterized in that for the microwave pretreatment equipment without an electric heater at the bottom in Step (2), the preheating mode is as follows: place a non-metal container filled with water in the center of the bottom of the resonant cavity, with the bottom of the container fully contacted with the bottom of the resonant cavity and the shape and the size of the container larger than or equal to that of wood test pieces, heat the water via microwave heating until the water is exactly boiling, take it out; and for the microwave pretreatment equipment with an electric heater at the bottom, warm up the temperature at the bottom of the resonant cavity to a certain preset temperature via a bottom electric heating mode, carry out Step (3) after the temperature is kept stable for 5-30 minutes, and maintain the electric heating at the bottom in the subsequent steps
5. The method for improving wood permeability according to Claim 2, 3 and 4, which is characterized in that in Step (3), place the wood test piece up to the pre-test temperature in the center of the bottom of the resonant cavity for microwave treatment, carry out microwave treatment, warm up the temperature of the test piece at least to the preset temperature, end the microwave treatment on the wood test piece, take out the wood test piece, record the time for the microwave treatment on the wood test piece, then put in next wood test piece up to the pre-test temperature, carry out microwave treatment on the second and following wood test pieces up to the pre-test temperature with the microwave treatment time corresponding to the preset temperature, and repeat this step until the temperatures of the microwave treatment on the wood test piece are basically the same, i. e. the heating rate of wood test pieces is relatively stable; wherein, the duration from taking out the last wood test piece and putting in next wood test piece is a fixed value, with the error no more than 0.5 s.
6. The method for improving wood permeability according to Claim 5, which is characterized in that in Step (4), place the wood test piece in the center of the bottom of the resonant cavity for microwave treatment, the microwave treatment time equals to the microwave treatment time corresponding to the preset temperature, end the microwave treatment on the wood test piece, take out the wood test piece, put in the next wood test piece, repeat this step until all the wood test pieces are treated, wherein, the duration from taking out the last wood test piece and putting in next wood test piece is a fixed value, with the error no more than 0.5 s.
7. The method for improving wood permeability according to Claim 6, which is characterized in that the wood test piece subjected to microwave treatment is placed in an oven at 60 °C and dried until the moisture content is less than 10%, and is absolutely dried by increasing the oven temperature to 103 °C,
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2020103153A AU2020103153A4 (en) | 2020-10-30 | 2020-10-30 | Method for improving wood permeability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2020103153A AU2020103153A4 (en) | 2020-10-30 | 2020-10-30 | Method for improving wood permeability |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| AU2020103153A4 true AU2020103153A4 (en) | 2021-01-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2020103153A Ceased AU2020103153A4 (en) | 2020-10-30 | 2020-10-30 | Method for improving wood permeability |
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| Country | Link |
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| AU (1) | AU2020103153A4 (en) |
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2020
- 2020-10-30 AU AU2020103153A patent/AU2020103153A4/en not_active Ceased
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