CN102554990A - Wood drying method - Google Patents
Wood drying method Download PDFInfo
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- CN102554990A CN102554990A CN201210018717XA CN201210018717A CN102554990A CN 102554990 A CN102554990 A CN 102554990A CN 201210018717X A CN201210018717X A CN 201210018717XA CN 201210018717 A CN201210018717 A CN 201210018717A CN 102554990 A CN102554990 A CN 102554990A
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Abstract
The invention relates to a wood drying method, which is a method for controlling a wood drying process by wood stress. In a drying process, the bending degree of a stress test piece represents a stress value to control the temperature and the moisture of a drying kiln so as to control a wood drying process. Wood of a certain length is sawn on dried material; the sawn wood is equally divided into two parts on the half of the thickness direction along the fiber direction, i.e. a first stress test piece and a second stress test piece; except the wood surface, the two stress test pieces seal rest five surfaces to isolate the five surfaces from air; then, the five sealing surfaces of the second stress test piece are fastened by a fixing sleeve; the two stress test pieces are put on the position with the highest drying speed in the drying kiln along with the dried material; the stress of the dried material is judged according to the bending degree of the two stress test piece; and the bending degrees of the stress test piece is observed to control the temperature and the moisture of a drying medium and the drying kiln so as to guarantee the drying quality of the wood and prolong the service life of the dried material. The method is especially suitable for drying tree types which are difficult to dry.
Description
Technical field
The present invention relates to the method for the drying of wood, specifically is a kind of drying means through timber Stress Control timber drying.
Background technology
Timber drying control is meant under the prerequisite that guarantees wood drying quality, adjustment drying medium temperature, humidity, the rate of drying of control timber.Drying schedule is the program list that is used for controlling dry run, and drying schedule commonly used is the moisture content benchmark, promptly according to temperature, the humidity of being stipulated different drying stage drying mediums by bole size of moisture content in dry kiln.And the stress that the immediate cause that influences wood drying quality is in the timber drying to be produced.Therefore through the timber drying of moisture content benchmark control, can not directly reflect by the stress intensity of bole in dry run, so occur the dry mass problem easily in the control of dry run.At present, the method for the brief introduction test drying of wood stress that often uses mainly is the broach method, and this method test value has only reflected the drying stress index of timber, can not detect by real-time online, and test value will lag behind drying regime at that time, and is ageing poor; Over nearly 20 years; Along with progress of science and technology, the method for testing of some new drying of wood stress has appearred, acoustic-emission test drying of wood stress again; Reflect the drying stress of timber through the dielectric constant of measuring timber, the grid touch sensor is used for timber stress and detects.But these technology are all very immature for various reasons, and limitation is separately arranged.
Summary of the invention
To above-mentioned existing in prior technology problem, but the object of the present invention is to provide a kind of real-time online to detect and the drying means of the timber that dry mass is good.
For achieving the above object, the technical scheme that the present invention adopted is: a kind of drying means of timber is characterized in may further comprise the steps through the method for timber Stress Control timber drying:
A) before the drying of wood: what never get into dry kiln is made two stress test specimens by saw on the bole; Five faces of one of them stress test specimen are sealed up the formation first stress test specimen, form the second stress test specimen with again these five faces being fixed with fixed cover after same five faces sealing of another stress test specimen;
B) drying of wood initial stage: observe the flexibility of the first stress test specimen at any time, according to temperature, the humidity of its flexibility adjustment drying medium;
C) drying of wood intermediary and later stages: observe the flexibility of the second stress test specimen at any time, in conjunction with the flexibility of the first stress test specimen, temperature, the humidity of adjustment drying medium.
Wherein, above-mentioned steps a) in from being by the mid portion of bole by the stress test specimen of bole saw system, the timber of mid portion is divided into two parts at half place of thickness direction along machine direction, these two parts are the first stress test specimen and the second stress test specimen.
In order to make test specimen when testing, can draw comparatively accurate data from the distortion situation of single face; Above-mentioned steps a) in the first stress test specimen and the second stress test specimen will remaining five faces sealing except wood surface through the masking foil adhesive tape, these five faces and air are completely cut off and the moisture that is implemented in these five faces in the dry run can not evaporate.
Dismantle and install and fix cover for ease; The fixed cover of above-mentioned steps in a) comprises press strip, fixed head, binding groove and holding screw; Wherein said fixed head is adjacent to face relative with the unsealing face in the second stress test specimen; Said press strip is established four and be close to other four sealing surfaces in the second stress test specimen respectively altogether, said binding groove be buckled on the second stress test specimen around and be tightened through holding screw and realize that the second stress test specimen is indeformable in dry run.
Above-mentioned steps b) flexibility of the first stress test specimen is the sign of surperficial tension in the timber drying in, and temperature, the humidity of adjusting drying medium according to the size of the first stress test specimen flexibility are not more than by the tensile strength perpendicular to grain of bole by the surperficial tension of bole with maintenance; Above-mentioned steps c) before the flexibility of observing the second stress test specimen, needs in earlier fixed cover to be removed; The second stress test specimen will be crooked along the opposite face direction of band direction unsealing face this moment; The flexibility of the second stress test specimen is the sign of inner band tension in the summer wood dry run, and temperature, the humidity of adjusting drying medium according to the size of the second stress test specimen flexibility are not more than by the tensile strength perpendicular to grain of bole by the inside tension of bole with maintenance.
The present invention be owing to will be made into the first stress test specimen and the second stress test specimen from the timber of being made by bole saw, with wherein five face seals of the first stress test specimen, and the second stress test specimen sheathed fixed cover outside all sealing surfaces also except five face seals wherein; When dry with this two stress test specimen with being put into dry kiln by bole, place the fastest place of drying kiln for drying, at the dry initial stage; The first stress test specimen has only the unsealing face can evaporate moisture content, and the inner moisture content of timber is distributed on the thickness direction asymmetric, and the inner moisture gradient of timber makes the first stress test specimen generation band crooked; Judge the size of wood surface tension according to the big I of flexibility; Thereby temperature, the humidity of adjustment drying medium guarantee that the suffered tension of wood surface is not more than the tensile strength perpendicular to grain of timber, split to prevent timber generation table, have arrived the dry middle and later periods; Wood surface produces the stretcher strain of plasticity band; Hardening phenomenon appears in the surface, makes timber demonstrate inside and receives action of pulling stress, unclamps the second stress test specimen fixing; The second stress test specimen will be crooked to the opposite face direction of unsealing face along the band direction this moment; Judge the size of the inner band tension of timber according to the big I of flexibility, thereby adjust temperature, the humidity of drying medium, timber is carried out high temperature, high humidity treatment; Eliminate or reduce the hardenability of wood surface, produce implosion to prevent timber.In sum, through observing the flexibility of the first stress test specimen and the second stress test specimen, can judge in the dry run by the size of the surface stress of bole and internal stress; Thereby adjustment drying medium temperature, humidity; So can effectively improve dry mass, but and real-time online detect, test value is accurate; Guaranteed the quality of manufactured goods; Improved the service life of manufactured goods simultaneously, this method for drying wood be the most directly, the most effectively, can guarantee the indehiscent method of timber, and this method is specially adapted to the drying of difficult dried seeds.
Below in conjunction with accompanying drawing the present invention is further described.
Description of drawings
The perspective view that Fig. 1 the present invention two stress test specimens are drawn materials.
The perspective view that Fig. 2 the present invention first stress test specimen is partly analysed and observe.
The perspective view that Fig. 3 the present invention second stress test specimen is partly analysed and observe.
The specific embodiment
Extremely shown in Figure 3 like Fig. 1; The drying means of a kind of timber provided by the invention; It mainly is method through timber Stress Control timber drying; May further comprise the steps: a) before the drying of wood: what never get into dry kiln is made two stress test specimens by saw on the bole, five faces of one of them stress test specimen is sealed up form the first stress test specimen 1, forms the second stress test specimen 2 with these five faces being fixed with fixed cover after same five faces sealing of another stress test specimen again; B) drying of wood initial stage: observe the flexibility of the first stress test specimen 1 at any time, according to temperature, the humidity of its flexibility adjustment drying medium; C) drying of wood intermediary and later stages: observe the flexibility of the second stress test specimen 2 at any time, in conjunction with the flexibility of the first stress test specimen 1, temperature, the humidity of adjustment drying medium.
As shown in Figure 1; It is following that the stress test specimen of this embodiment is produced process: it is whole to be by a timber in the bole; To separate be three parts along saw on the timber length direction with it, and the part between getting wherein is used to produce the stress test specimen, and the mid portion of sawing out is divided into two parts up and down at half place of thickness direction along machine direction immediately; Wherein top is as the first stress test specimen 1, and its upper surface is the A face; The lower part is as the second stress test specimen 2, and its lower surface is the B face.
As shown in Figure 2, adopt the encapsulant of masking foil adhesive tape 3 to seal up immediately the first stress test specimen 1 and the second stress test specimen 2 except A face and five faces the B face, prevent these five faces transpiring moisture in dry run.
As shown in Figure 3; The fixed cover of this embodiment is the stainless steel fixed cover; It includes stainless steel press strip 41, stainless steel fixed head 42, stainless steel binding groove 43 and stainless steel holding screw 44, and the opposite face and the stainless steel fixed head 42 of the face of the second stress test specimen 2 of good seal closely is adjacent to, and closely is adjacent to stainless steel press strip 41 around the B face; Buckling with the stainless steel binding groove 43 that has stainless steel holding screw 44 all around again after being adjacent to stainless steel; The stainless steel holding screw 44 of screwing simultaneously, make stainless steel press strip 41 be pressed in the second stress test specimen 2 around, purpose is to guarantee that the second stress test specimen 2 is indeformable in dry run.
Gone into kiln drying by bole when dry; With the first stress test specimen 1 and the second stress test specimen 2 be placed on the fastest place of drying kiln for drying by bole; The first stress test specimen 1 is the size that is used for testing dry run moisture content stress, promptly because the stress that moisture gradient causes.The second stress test specimen 2 is to be used for testing dry run residual stress and the synthetic size of moisture content stress, and residual stress is meant the timber stress that residual deformation causes in dry run.In dry run, the wood surface water evaporates makes the low inside and high outside moisture gradient of the inner generation of timber.Wherein, at the dry initial stage, moisture gradient causes wood surface to receive tension, inner compression chord, and the suffered tension of wood surface is greater than the tensile strength perpendicular to grain of timber, and then timber can split by the generation table.In order to prevent that timber generation table from splitting; Only make the tension of wood surface be not more than the tensile strength perpendicular to grain of timber; And the size of the tension of wood surface through the first stress test specimen, 1 flexibility reflect, in dry run, the first stress test specimen 1 has only the surfaces A can transpiring moisture; The inner moisture content of timber is distributed on the thickness direction asymmetric; It is crooked that the inner moisture gradient of timber makes the first stress test specimen 1 that band take place, and judges the size of wood surface tension according to the size of flexibility, thereby according to temperature, the humidity of the first stress test specimen, 1 flexibility adjustment drying medium; Make the flexibility of stress test specimen be not more than the critical bends degree, the critical bends degree promptly reflects the timber tensile strength perpendicular to grain.After testing the flexibility of the first stress test specimen 1, be put back into the original position of dry kiln to the first stress test specimen 1 immediately.
Along with going deep into of degree of drying; Because the existence of the tension of dry initial stage wood surface under action of temperature, makes wood surface produce the stretcher strain of plasticity band; Surperficial hardening phenomenon appears; Simultaneously the moisture content of timber reduces gradually, and moisture gradient reduces gradually, and the flexibility of the first stress test specimen 1 reduces under the constant situation of drying medium state gradually.When the inner moisture content of timber is reduced to fibre saturated point when following, inner beginning drying shrinkage is because the sclerosis of wood surface makes timber demonstrate inside and receives action of pulling stress, outside compression chord effect.Inner tension is during greater than the tensile strength perpendicular to grain of timber, and timber can produce implosion.In order to prevent the generation of implosion, make the inner tension of timber be not more than the tensile strength perpendicular to grain of timber, have only the surface sclerosis of elimination or reduction timber, just make timber not produce implosion.Temperature, humidity through the adjustment drying medium are carried out hot and humid processing to timber, make the timber top layer softening, under the effect of compression, eliminate or reduce the sclerosis of wood surface, reach the effect of eliminating or reducing the inner tension of timber.When the flexibility of the first stress test specimen 1 begins to reduce to a certain degree; When the inner moisture content of timber is lower than fibre saturated point; Holding screw on the second stress test specimen 2 is unscrewed, take out the second stress test specimen 2, at this moment; The second stress test specimen 2 will be crooked to the opposite face direction of B face along the band direction, the size of the inner band tension of this flexibility size reflection timber.Adjust temperature, the humidity of drying medium according to the flexibility of the second stress test specimen 2; Timber is carried out high temperature, high humidity treatment, make the timber top layer softening, under the effect of compression; Eliminate or reduce the hardenability of wood surface, reach the effect of eliminating or reducing the inner tension of timber.Hardenability is timber top layer band stretching residual deformation degree, and the flexibility that the temperature, humidity through the adjustment drying medium guarantees to make the second stress test specimen 2 is less than the critical bends degree, and the critical bends degree promptly reflects the timber tensile strength perpendicular to grain.After testing the second stress test specimen, 2 flexibility sizes, put into the stainless steel fixed mount the second stress test specimen 2 after fixing the origin-location of dry kiln again.Can reach the purpose of the present invention through above enforcement through the Stress Control timber drying.
The present invention describes through embodiment; But the present invention is not constituted restriction, with reference to description of the invention, other variations of the disclosed embodiments; Professional person as for this area expects that easily such variation should belong within the scope thereof of the present invention.
Claims (6)
1. the drying means of a timber is characterized in that may further comprise the steps through the method for timber Stress Control timber drying:
A) before the drying of wood: what never get into dry kiln is made two stress test specimens by saw on the bole; Five faces of one of them stress test specimen are sealed up the formation first stress test specimen (1), form the second stress test specimen (2) with again these five faces being fixed with fixed cover after same five faces sealing of another stress test specimen;
B) drying of wood initial stage: observe the flexibility of the first stress test specimen (1) at any time, according to temperature, the humidity of its flexibility adjustment drying medium;
C) drying of wood intermediary and later stages: observe the flexibility of the second stress test specimen (2) at any time, in conjunction with the flexibility of the first stress test specimen, temperature, the humidity of adjustment drying medium.
2. the drying means of timber according to claim 1; It is characterized in that during above-mentioned steps a) from by the stress test specimen of bole saw system for by the mid portion of bole; The timber of mid portion is divided into two parts at half place of thickness direction along machine direction, and these two parts are the first stress test specimen (1) and the second stress test specimen (2).
3. the drying means of timber according to claim 1; It is characterized in that during above-mentioned steps a) that the first stress test specimen (1) and the second stress test specimen (2) will remaining five faces sealings except wood surface through masking foil adhesive tape (3), these five faces and air are completely cut off and the moisture that is implemented in these five faces in the dry run can not evaporate.
4. the drying means of timber according to claim 1; It is characterized in that the fixed cover during above-mentioned steps a) comprises press strip (41), fixed head (42), binding groove (43) and holding screw (44); Wherein said fixed head (42) is adjacent to the face relative with the unsealing face in the second stress test specimen (2); Said press strip (41) is established four altogether and also is close to other four sealing surfaces in the second stress test specimen (2) respectively, and said binding groove (43) is buckled on also being tightened through holding screw (44) of the second stress test specimen (2) all around and realizes that the second stress test specimen (2) is indeformable in dry run.
5. the drying means of timber according to claim 1; It is characterized in that above-mentioned steps b) in the flexibility of the first stress test specimen (1) be the sign of surperficial tension in the timber drying, be not more than by the tensile strength perpendicular to grain of bole by the surperficial tension of bole keeping according to the temperature of the size adjustment drying medium of first stress test specimen (1) flexibility, humidity.
6. the drying means of timber according to claim 1; It is characterized in that above-mentioned steps c) in before observing the flexibility of the second stress test specimen (2), need first fixed cover is removed; The second stress test specimen (2) will be crooked along the opposite face direction of band direction unsealing face this moment; The flexibility of the second stress test specimen (2) is the sign of inner band tension in the summer wood dry run, and temperature, the humidity of adjusting drying medium according to the size of second stress test specimen (2) flexibility are not more than by the tensile strength perpendicular to grain of bole by the inside tension of bole with maintenance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210018717.XA CN102554990B (en) | 2012-01-20 | 2012-01-20 | Wood drying method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210018717.XA CN102554990B (en) | 2012-01-20 | 2012-01-20 | Wood drying method |
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| Publication Number | Publication Date |
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| CN102554990A true CN102554990A (en) | 2012-07-11 |
| CN102554990B CN102554990B (en) | 2015-07-15 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210018717.XA Expired - Fee Related CN102554990B (en) | 2012-01-20 | 2012-01-20 | Wood drying method |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106225969A (en) * | 2016-08-09 | 2016-12-14 | 东北林业大学 | A kind of timber drying stress appraisal method controlled for lumber quality |
| CN110186757A (en) * | 2019-05-23 | 2019-08-30 | 南京林业大学 | A kind of method of timber crack in inhibition drying process |
| CN113618855A (en) * | 2021-07-07 | 2021-11-09 | 南京林业大学 | Bionic wood-based humidity indicator and preparation method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004190957A (en) * | 2002-12-11 | 2004-07-08 | Sumitomo Forestry Co Ltd | Timber drying method |
| CN101149370A (en) * | 2007-10-30 | 2008-03-26 | 东北林业大学 | Timber drying stress detection device and method |
-
2012
- 2012-01-20 CN CN201210018717.XA patent/CN102554990B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004190957A (en) * | 2002-12-11 | 2004-07-08 | Sumitomo Forestry Co Ltd | Timber drying method |
| CN101149370A (en) * | 2007-10-30 | 2008-03-26 | 东北林业大学 | Timber drying stress detection device and method |
Non-Patent Citations (2)
| Title |
|---|
| 蒋佳荔等: "木材干燥应力的研究方法与进展", 《木材工业》 * |
| 高建民等: "木材干燥应力连续监测方法的研究", 《木材工业》 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106225969A (en) * | 2016-08-09 | 2016-12-14 | 东北林业大学 | A kind of timber drying stress appraisal method controlled for lumber quality |
| CN106225969B (en) * | 2016-08-09 | 2018-11-06 | 东北林业大学 | A kind of timber drying stress appraisal method for lumber quality control |
| CN110186757A (en) * | 2019-05-23 | 2019-08-30 | 南京林业大学 | A kind of method of timber crack in inhibition drying process |
| CN110186757B (en) * | 2019-05-23 | 2021-11-05 | 南京林业大学 | Method for inhibiting wood cracking in drying process |
| CN113618855A (en) * | 2021-07-07 | 2021-11-09 | 南京林业大学 | Bionic wood-based humidity indicator and preparation method thereof |
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| Publication number | Publication date |
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| CN102554990B (en) | 2015-07-15 |
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Granted publication date: 20150715 Termination date: 20190120 |