Wood hnyav
Qhov hnyav ntawm ntoo nyob ntawm nws qhov ntom thiab qhov dej noo nws muaj. Muaj qhov tshwj xeeb lub ntiajteb txawj nqus ntawm cov khoom ntoo thiab qhov hnyav ntawm cov ntoo.
Qhov hnyav ntawm ntoo tsis nyob ntawm seb hom ntoo. Nws qhia txog qhov hnyav ntawm cov khoom siv ntoo hauv ib chav tsev, tsis muaj dej noo thiab huab cua, thiab yog 1,5.
Hauv kev xyaum, qhov hnyav hnyav ntawm cov ntoo yog siv, uas yog, qhov hnyav ntawm 1 cm³ ntoo loj qhia hauv grams. Raws li qhov ntim qhov hnyav, qhov hnyav ntawm cov ntoo thiab nws cov khoom siv tau kwv yees. Nrog nce av noo, volumetric hnyav ntawm ntoo kuj nce. The higher the density, the denser and less porous the wood.
Ntoo humidity
Hom dej hauv ntoo
Cov dej hauv tsob ntoo tau muab faib ua:
- ** capillary (dawb) ** - sau cov kab noj hniav ntawm tes;
- ** hygroscopic ** - pom nyob rau hauv cell phab ntsa;
- ** chemical ** - nkag mus rau hauv cov tshuaj muaj pes tsawg leeg ntawm cov khoom uas ua rau ntoo.
Tus nqi ntawm cov dej hauv ntoo, qhia hauv qhov hnyav feem pua, yog hu ua ** ntoo ya raws **. Muaj qhov tseeb thiab txheeb ze humidity.
txheeb ze thiab tsis muaj av noo
Yog tias qhov hnyav ntawm cov ntoo hauv nws lub xeev qub raug cim nrog tsab ntawv **A **, qhov hnyav ntawm cov ntoo qhuav nrog tsab ntawv ** A₁ **, cov av noo nyob rau hauv feem pua nrog tsab ntawv ** B **, thiab cov av noo hauv feem pua nrog tsab ntawv ** B₁ **, cov av noo ntawm cov txheeb ze tuaj yeem txiav txim siab raws li cov qauv hauv qab no:
- Daim ntawv rau cov av noo ntawm cov ntoo.*
Tsis muaj av noo yog txiav txim siab raws li cov qauv hauv qab no:
- Daim ntawv rau cov av tsis muaj tseeb.*
Kev txiav txim siab ntawm cov av noo
A prism raug txiav los ntawm nruab nrab ntawm lub rooj tsavxwm thiab ntsuas ntawm qhov ntsuas nrog qhov tseeb ntawm 0,01 g. Tus nqi tshwm sim sawv cev qhov loj ntawm A. Lub prism, nws qhov hnyav yuav tsum tsis txhob tsawg dua 20 g, ces qhuav ntawm qhov kub ntawm 105° kom txog thaum nws nce mus txog qhov hnyav tas li A₁.
Qhov hnyav tas li yog txiav txim siab ua tiav yog tias qhov sib txawv ntawm ob qhov kev ntsuas sib law liag tsis ntau dua 0,3% qhov hnyav qhuav. Los ntawm kev nkag mus rau qhov tseem ceeb A thiab A₁, tau los ntawm kev ntsuas, nyob rau hauv cov ntaub ntawv teev, tus txheeb ze los yog kiag li humidity ntawm ntoo yog txiav txim.
Yog thawj qhov hnyav ntawm qhov prism txiav los ntawm nruab nrab ntawm lub rooj tsavxwm yog 240 g, thiab qhov hnyav ntawm cov ntoo qhuav 160 g, qhov av noo ntawm cov qauv kuaj yog:
- Piv txwv ntawm kev xam cov av noo ntawm cov qauv kuaj.*
Cov av noo tau los ntawm txoj kev no yog suav tias yog cov av noo ntawm tag nrho cov ntoo.
Fiber saturation point
Thaum ziab ntoo, dej dawb evaporates ua ntej. Lub sijhawm thaum tag nrho cov dej evaporates yog hu ua hygroscopic txwv lossis fiber ntau saturation point. Thaum lub sij hawm ziab no, qhov ntev ntawm cov ntoo qhuav tsis hloov.
Cov av noo sib xws rau hygroscopic txwv rau ntau hom ntoo muaj npe nyob rau hauv cov lus hauv qab no:
| Hom ntoo | Humidity |
|---|---|
| Pine qub | 29% |
| Weymouth ntoo | 25% |
| Spruce | 29% |
| Larch | 30% |
| Spruce | 30% |
| Beech | 31% |
| tsob ntoo linden | 29% |
| Tshauv | 23% |
| Chestnut | 25% |
Influence of humidity on processing and durability of ntoo
Ntoo nrog cov av noo ntau ntxiv yog cov khoom siv hluav taws xob zoo ntawm cov cua sov, nws tau ua tiav los ntawm cov tshuab, nws tsis zoo glued, pleev xim rau, varnished thiab polished. Xim thiab cov kua roj vanish sai sai disintegrate rau saum npoo ntawm cov xim ntub dej. Cov ntoo ntub ua rau cov ntsia hlau thiab cov ntsia hlau xeb.
Qhov ntev ntawm cov khoom siv ntoo ua los ntawm cov ntoo nyoos - qhov rooj, qhov rais, cov plag tsev, parquet thiab lwm yam khoom - ntsws thaum ziab. Vim li no, cov kab nrib pleb tshwm thiab qhov nruj ntawm kev sib txuas ntawm cov khoom ploj.
Yog li ntawd, qhov zoo ntawm cov ntoo hauv kev tsim kho, nws cov kav ntev thiab tiv thaiv rotting yog txiav txim siab feem ntau los ntawm nws cov av noo, thiab tom qab ntawd los ntawm hom ntoo thiab cov xwm txheej ntawm kev siv. Raws li cov xwm txheej ntawm kev siv, cov ntoo qhuav tuaj yeem ua haujlwm hauv cov tsev rau ntau xyoo.
Qhov hnyav ntawm ntoo thaum ziab
Thaum lub sij hawm ziab, ntoo hloov nws qhov ntev: nyob rau hauv longitudinal kev taw qhia rau0,10%, nyob rau hauv lub radial rau3-6%, thiab nyob rau hauv tangential rau6-12%. Qhov kev hloov no hu ua qhov hnyav.
Qhov hnyav pib thaum cov av noo mus txog qhov saturation ntawm cov fibers, los ntawm23%rau31%. Anatomical ntsiab uas ua rau cov ntoo nyob rau hauv cov txheej txheem kom qhuav shrink unevenly, yog li ntawd lub luj ntawm cov ntoo yog txawv nyob rau hauv txawv kev qhia.
Ntoo uas muaj qhov ntom ntom ntom ntom, xws li ntoo qhib, hnyav dua li ntoo nrog qhov ntom ntom, xws li linden. Hauv hom conifer, qhov loj ntawm qhov hnyav kuj nyob ntawm kev koom tes ntawm cov ntoo lig. Nrog rau qhov nce hauv feem pua ntawm cov ntoo lig hauv ntoo thuv, qhov hnyav nce, vim tias cov ntoo lig ntawm cov hom coniferous hnyav hnyav dua thaum ziab dua li cov ntoo thaum ntxov.
Qhov hnyav ntawm cov ntoo thaum ntxov thiab lig ntawm coniferous hom
| VRSTA DRVETA | Ib feem ntawm tsob ntoo | NYIAJ % | ||
|---|---|---|---|---|
| Nyob rau hauv txoj kev tangent | Nyob rau hauv cov kev taw qhia radial | Volumetrically | ||
| Noj | Thaum ntxov | 5.68 | 2.89 | 8.77 |
| lig | 10.92 | 9.85 | 19.97 | |
| Bor | Thaum ntxov | 8.05 | 2.91 | 10.86 |
| lig | 11.26 | 8.22 | 10.87 | |
| Larch | Thaum ntxov | 7.11 | 3.23 | 10.34 |
| lig | 12.25 | 10.19 | 20.96 | |
Nyhav ntau hom ntoo
| VRSTA DRVETA | NYIAJ % | ||
|---|---|---|---|
| Nyob rau hauv cov kev taw qhia radial | Nyob rau hauv txoj kev tangent | Volumetrically | |
| Bor | 3.4 | 8.1 | 12.5 |
| Spruce | 4.1 | 9.3 | 14.1 |
| Larch | 5.3 | 10.4 | 15.1 |
| Jasen | 4.8 | 8.2 | 13.5 |
| Oak | 4.7 | 8.4 | 12.7 |
| Bukva | 4.8 | 10.8 | 15.3 |
Huab cua thiab tawg
Kev hloov pauv tsis sib xws hauv cov txheej txheem ntawm qhov hnyav vim ziab, nrog rau kev siv cov txheej txheem ziab kom tsis raug, ua rau muaj kev ntxhov siab sab hauv thiab sab nraud hauv ntoo. Lawv ua rau huab cua thiab cov tsos ntawm sab nraud thiab qee zaum sab hauv tawg.
Tangentially txiav cov laug cam yog qhov ua rau huab cua ntau dua li cov ntawv txiav radially. Qhov lawv nyob ze rau ntawm qhov chaw, qhov cua tshuab ntau dua.
Image 3. Winding cov laug cam raws li txoj hauj lwm hauv lub cav.
Cov kab nrib pleb sab nraud yog tshwm sim los ntawm kev ziab tsis sib xws ntawm cov txheej ntoo sab nrauv thiab sab hauv. Vim qhov sib txawv loj ntawm lawv cov av noo, tensile stresses tshwm rau saum npoo ntawm ntoo, uas ua rau sab nrauv tawg.
Txhawm rau kom tsis txhob pom cov kab nrib pleb sab nraud, cov txheej txheem ziab yuav tsum tau ua kom qeeb thiab sib npaug. Tom qab ntawd qhov kev hloov pauv ntawm qhov ntev yuav maj mam, yog li cov rog uas ua rau tawg yog me me.
Ntoo dries sai dua ntawm pem hauv ntej, uas yog vim li cas rau pem hauv ntej ntawm boards, billets thiab round ntoo tawg ua ntej tshaj lwm qhov chaw. Txhawm rau kom tsis txhob tawg, lub hauv pliaj yuav tsum tau tiv thaiv los ntawm kev cuam tshuam tas mus li ntawm lub hnub lub rays los ntawm cov txheej txheem tiv thaiv los yog muab tso rau hauv qhov ntxoov ntxoo.
Tsob Ntoo o
o ntawm cov ntoo yog cov txheej txheem rov qab ntawm ziab thiab hnyav. Cov ntoo qhuav tuaj yeem nqus dej noo thiab ua kom nws qhov ntev. Cov yam ntxwv no yog siv los moisten cov thoob qhuav, cov kav ntoo, tso tsheb hlau luam thiab lwm yam khoom, ua rau lawv o.