一种新型高温空气湿度仪

国外80年代出现了一种与木材工业单板干燥机及其它高温干燥设备相配套的新型高温空气湿度仪。它能连续检测温度高达500℃的空气介质的水蒸气容量百分比(VOL％)(以下单称湿度),并实现排湿量自动控制,节能效果十分显著。     

分析单板干燥规律 完善单板干燥机的设计

１ 木材含水特性及单板干燥规律 木材中所含的水分可分为两部分。一部分存在于木纤维中，称为吸附水；当木纤维吸附水达到饱和后，再多余的水就存在于细胞腔中，这种水称自由水。当吸附水刚刚达到饱和，而无自由水时，木材的含水率称为临界含水率。不同树种的临界含水率各不相同，一般都在２５％～３５％之间。临界含水率是影响木材物理、力学性质的临界线。试验证明，当木材含水率小于临界含水率时，木材强度也随之明显变化：含水率越低，木材强度越高；反之，木材强度越低。单板干燥的目的就是通过加热方式，强制蒸发掉单板中的水分，降低…     

TH—Ⅱ型便携式温湿度仪的研究

ＴＨ─Ⅱ型便携式温湿度仪的研究曹冠武，陈有才，丁俊岭（河南省护林防火办公室）（解放军信息工程学院）张申广，黄广春，杜合庄（郑州市林业工作站）（济源市护林防火办公室）ＴＨ—Ⅱ型便携式温湿度仪的研制立足于森林防火工作的实际需要，选用当今世界上最先进的电子...     

我国单板加工主要设备的开发及特性分析

阐述胶合生产的关键设备--旋切机的研发过程,及各种旋切机的优缺点,并详细介绍有卡-无卡组合式旋切机、辊压连续式单板干燥机和网辊复合式单板干燥机,及单板纵向接长机组的结构和工作原理,为胶合板类生产企业技术改造和设备选型提供参考.     

电子测径仪的研制

电子测径仪属国内首创，它的研制成功标志着我国森林调查工具的一次重要突破。该仪器的研制主要是在测径仪动尺上设计了容栅测量电路和由ＣＭＯＳ电路组成的单片微处理器，单片机的信号输入接口与动尺上的容栅感应电极之间，经数据线传输；设计了由ＣＤ４０２２和ＣＤ４０９４组成的串并转换电路，将容栅感应电极拾取的测量信号脉冲串转换为并行数据，以便于微处理器处理，ＬＣＤ显示输出信号，也可通过接口将数据输出到通用计算机上作更复杂的处理和打印，或与数据采集仪联机解决野外数据的存储、传输问题。     

MWMY型木材微密度测定仪的研制

为开拓木材密度变异性的研究，中国林科院木工所与北京科信机电技术研究所合作研制成功了ＭＷＭＹ型木材微密度测定仪。本文报道了研制中解决的主要技术问题。包括仪器选型、总体布局、光栏、测量系统标定、微密度测定方法、软件系统系统和精度考核等项。测量精度与国外类似试验装置水平接近，在光栏结构，软件设计，质量衰减系数标定和试样制作工具方面有所创新。     

非称量测渗仪的研制与应用

在着重介绍研制“非称量测渗仪”目的意义，国内外研究现状，研制发展过程的同时，简要地介绍了利用“非称量测渗仪”进行研究的内容，方法和所得的主要成果。     

电肥仪研制及对落叶松苗应用技术的研究

电肥仪是根据植物电生理原理研制出可取代追施化肥的一种新型促进植物生长的电子仪器。该仪器由高压电脉冲发生器和输出匹配系统两部分组成,可与各种喷雾机具配套使用。应用电肥仪正4KV电压,200H_2以上脉冲频率,以水作载体,在落叶松苗速生期处理3～4次,比同期追施3～4次化肥的苗木,苗高、地径生长量分别提高19.2％和13.8％,成苗率提高15.1％,根系发达,干鲜重增加也很显著。应用电肥仪处理的圃地土壤养分利用率有所提高。与追施化施相比,每公顷多创产值一万多元。     

生产常用单板干燥机的热能利用分析

为了 解当前单板干燥设备的能量利用情况,结合生产常用单板干燥设备及实际干燥工艺,对3类国产及进口的单板干燥机,进行热能利用分析.结果表明:单板干燥机排出的湿空气热量占总能耗的60％以上,是优先考虑的关键节能环节;排出的冷凝水能量及干燥机泄漏的热能,亦分别占干燥机总能量消耗的10％～17％.针对上述结果,提出进行设备节能改造、提高能量利用效率的建议.     

林业数字式测径仪的研制

林业数字式测径仪是以测量新方法自动分臂三切点法为理论基础,以角位移传感器、单片机、显示屏等电子器件所组成的集中电路并结合机械设计与加工为技术特征从而实现仪器装置的.仪器具有结构轻巧、操作简便、高精度及高效率等特点,主要解决了森林计测领域直径测量数字式读数、非触式测量、大树测量与标准地每木检尺的自动统计等问题.对已申报的发明专利产品——数字式测径仪的构造、原理、特点等进行了阐述,以期将科技成果迅速转化为现实生产力.     

柔性垫网接触式间歇干燥单板的生产性试验

利用柔性垫网接触式间歇干燥单板的方法对杨木单板进行干燥的生产性试验.通过生产性试验验证了此方法较佳生产工艺条件的变化规律,试验结果表明:(1)采用双面配置柔性垫网是合理的,排汽作用显著,干燥后单板含水率均匀,效果良好.(2)接触式间歇干燥单板,当单板芯部达到汽化温度(100℃)时,热板开启排汽时间越早,越利于单板表面自由水的快速排除,有助于提高单板干燥速度和质量.(3)接触式间歇干燥单板,其质量优于接触式连续干燥单板,更优于采用空气对流式干燥单板的方法.生产性试验证明,此方法为解决单板干燥变形(尤其是速生树种材单板变形)提供了可靠的技术保证,其生产工艺是可行的.     

桐竹混交培育泡桐单板材的研究

利用生物种群共生的竞争作用，通过３种密度的桐竹混交试验，研究在复层混交条件下培育泡桐单板材的可能性。结果表明，桐竹混交在沿海地区有较强的抗风倒能力，能显著地提高泡桐的枝下高和主干高，使树干形数和圆满度显著增大，泡桐的单板材出材量提高５０％以上。     

Performance of samama (Anthocephalus macrophyllus) LVL based on veneer thickness,juvenile proportion and lay-up

ABSTRACT

A study to determine the quality of laminated veneer lumber (LVL) from samama wood (Anthocephalus macrophyllus) was carried out. Samama is a fast-growing endemic wood in eastern Indonesia. Factorial of three factors in RAL design was used to investigate the influence of veneer thickness, juvenile proportion and veneer lay-up to the quality of the resulted samama LVL. The veneer thicknesses were 1.5 and 3.0?mm. Juvenile proportions were arranged in five levels, which were 100% of juvenile veneer, 100% of mature veneer and combination of both juvenile and mature with juvenile proportion of 14%, 43% and 71%. Two veneer lay-up used in this study were loose side met loose side and tight side met loose side. The result of the study showed various specific gravity of LVL by different proportions of juvenile. This factor also affected the other physical traits. Shear strength of the LVL was equal to the solid wood, yet MOE and MOR were affected by juvenile proportion and veneer lay-up. LVL developed from 100% of mature veneer exhibited the highest MOE and MOR, yet no significant difference was noted in MOE and MOR between LVL 100% of juvenile and other tested juvenile proportions.     

Study on drying rate in contact drying with flexible screen

IntroductionA new type contact dryer with non-metal flexibleplaten was patented in 1998 in China, which specialstructure and material solved the problem of low productivity in platen drying. The machine was similar tohot press. Direct contact betWeen wood and heatedplaten allows rapid heat transfer by conduction (Sandoe 1983). Though the flexible screen conducts heatslower than metal platen does, it transfers massmuch fast6r. So water removing rate decides veneerdrying rate in the new machin…     

高温热处理木材胶合性能的研究

笔者研究了桦木、落叶松和樟子松高温热处理材的胶合性能,并与常规干燥材进行了对比。测试结果表明木材的胶合剪切强度与所用的胶黏剂有关,聚氨酯胶合的三个树种木材的剪切强度普遍大于白乳胶胶合的木材。无论是室内用的白乳胶或室外木结构用的聚氨酯胶都能与三个树种的高温热处理材很好地胶合,胶合试件的浸渍剥离率或煮沸剥离率皆为零。木材经高温热处理后,其剪切强度均有不同程度的降低,阔叶材桦木下降幅度最大,针叶材落叶松下降幅度最小。     

A study on contact drying with flexible screen

hibobctionHOt press drying is referred to dry veneers betweenplat6ns. H6St is thensPOrt6d from plat6n to veneercontinuousty (Sandoe 1983). Many experiments haveshown that hot press may reduce drying time andIncreaSe h6at nescient. In addition, hot press driedveneer is flat and smOOth, which is desirable to glue,~bly as well as curtsin coat (Lu 1993). Compered We conventional air circulating drieF, hot pressdrier 1. simpler in struCture, cheaper in price andmore economical in operation (L…     

High-temperature drying of southern pine 2 by 4's: Effects on strength and load duration in bending

Summary Southern pine lumber specimens dried by conventional (82 °C maximum) and high temperature (116 °C for less than 1 day) schedules were tested to determine if high-temperature drying affects load duration. Results show that high-temperature drying has no appreciable effect on load duration, probably because it has no appreciable effect on static strength. Results from combining the data from both kinds of drying suggest that the load duration effect is less severe for lumber than for small clear specimens.     

Changes of decay and termite durabilities of Japanese larch (Larix leptolepis) wood due to high-temperature kiln drying processes

We investigated the effects of high-temperature drying schedules (120°–130°C) on decay and termite feeding of Japanese larch timbers. Thermogravimetric analysis was conducted to investigate changes of the wood components. Decay and termite feeding tests showed that specimens dried under high-temperature schedules were susceptible against a decaying fungus Fomitopsis palustris and attacks from termites Coptotermes formosanus and Reticulitermes speratus. These drying schedules changed chemical components, which were suggested by the thermal analytical result compared to the control sample. The results of this study indicated that the acceleration of termite feeding takes place even under temperatures that are comparatively lower than that used in our previous research in which 170°C steaming treatment was applied to Japanese larch wood. Decay durability against a brown rot fungus also decreased, possibly from production of low molecular weight fragments when hemicellulose decreased during the high-temperature drying processes.     

木材微波干燥缺陷产生原因及其预防措施分析

从木材介电特性、微波穿透深度、微波设备、干燥工艺等方面分析了木材微波干燥缺陷产生的主要原因,并从优化干燥器设计,改善微波场分布均匀性,控制微波辐射功率和辐射时间,改变微波辐射方式等方面探讨了预防干燥缺陷产生的主要措施,以期为木材微波干燥技术的研究和应用提供参考。     

多功能新型燃气设备在单户取暖上的应用

文章为单户取暖提供了经济可靠的新型设备,根除了收取采暖费的困境,对改善城市大气质量起到不可低估的作用。