落叶松小径木异型锯材的干燥均匀度

由于森林资源总体质量的下降,木材生产中小径木所占比例越来越大。小径木因其径级小、材质不稳定等缺点,使用受到限制。如何充分开发和高效利用小径木资源,成为当前国内外学者普遍关注的问题。目前,小径木大多作为木片、造纸和人造板的原料,这种利用方式投资大、产品单一、资金回收慢、经济效益低。而将小径木经过优化选材、优化设计和优化工艺的方法,加工成集成材、重组木等,可改善或提高小径木材质,克服径级小、利用单一的缺点,满足市场对木材的旺盛需求。     

常规干燥室余热回收装置的研究

分析研究具有强制集中换气木材干燥室的余热回收装置,并对其节能效果进行测试分析。对不同干燥阶段测试结果表明,从干燥室排出的通过余热回收装置后温度下降了13～16.3℃,补充到干燥室中的新鲜空气通过余热回收装置温度可以升高9～11.9℃。此余热回收装置的热回收效率为18.6%～28%,平均效率为22%,理论计算常规干燥每1m3、47mm厚的水曲柳的总排湿能量为1.4×106kJ,用该装置可节省热能为2.88×105kJ,相当于节省标准煤9.84kg。     

Effect of drying methods on the discoloration of three major domestic softwood species in Korea

1 Introduction Three major softwood species in Korea are Japanese pine (Pinus densiflora), Korean pine (Pinus koraiensis) and larch (Larix leptolepis) which have been used for traditional buildings and furniture for a long period of time. They are easily discolored due to drying and UV irradiation. It has been observed that the discoloration varies with different drying methods and the extent of UV irradiation (Mottonen and Luostarinen, 2001; Kang, 2003). To prevent beech from discolorat…     

计算流体力学数值仿真技术及其在木材干燥研究中的应用

计算流体力学（CFD）数值仿真技术是随着计算机科学发展起来的通过数值计算获得流场流动与传热规律的新技术,已逐渐成为木材科学领域中研究木材干燥技术的重要方法。文中对CFD仿真原理和方法进行阐述,从干燥室设计和优化、干燥室性能分析与干燥过程热质耦合传递等方面归纳总结国内外CFD技术在木材干燥研究中的应用现状,指出目前研究存在的不足并展望未来研究热点。     

40mm厚杉木锯材高温干燥工艺研究

对40 mm厚杉木锯材制定两个高温干燥工艺并进行试验研究,检测和分析干燥周期、干燥速率、锯材干燥质量等指标。干燥工艺I采用高温湿空气进行干燥;干燥工艺II在干燥前期高含水率阶段采用过热蒸汽条件,干燥后期低含水率阶段采用高温湿空气进行干燥。结果显示:两个干燥工艺在各阶段的干燥速率差异明显,干燥前期工艺II的干燥速率为1.30%/h,较工艺I低约37.2%;但干燥后期工艺II的干燥速率为1.89%/h,较工艺I高约70.27%。干燥工艺II可以有效避免锯材内裂的发生,干燥质量满足GB/T 6491—2012《锯材干燥质量》二级材的指标要求,干燥效率提高。     

我国木材干燥工业现状与科技需求

介绍木材干燥行业的现状、木材干燥工业取得的的主要科技成就,以及木材干燥领域的科研与开发进展;分析行业存在的主要技术问题和关键技术瓶颈,提出木材干燥行业在"十二五"期间的科技需求以及主要的任务.     

基于免疫算法的木材干燥窑PID控制系统

用神经网络方法对木材干燥窑PID控制系统进行系统辨识,并在此基础上用免疫PID算法取代传统PID算法进行PID参数的在线寻优,从而更加准确地控制干燥窑的温度和湿度的过程。仿真结果表明,新的控制系统在稳定性、动态性能等方面都有明显提高。     

Effects of high drying temperatures and restraint on twist of larch (Larix)

Abstract

During drying, timber changes its shape, mainly as a result of specific properties such as shrinkage anisotropy, radial differences in longitudinal shrinkage and spiral grain. The distortion, causing severe downgrading, can be reduced by restraining the timber and by using special drying schemes. The research described here is related to a project on the improvement of shape stability of Norway spruce. In the present part, different larch species from three stands were dried at high temperatures (80, 120 and 170°C). The effects of restraint during presteaming, drying and steaming on short-term twist reduction were investigated. The permanency of drying distortions was investigated in subsequent moisture cycling. Results showed a clear dependency of twist on the distance to pith. Restrained specimens sawn close to pith experienced reduced twist. This twist reduction was permanent during subsequent moisture variations. Drying temperature did not significantly influence twist and twist amplitude in moisture cycling.     

STEAMING-HIGH TEMPERATURE DRYING OF LARCH LUMBER

A series of drying tests on Larch Lumber and a theoretical analysis led to the follow-ing conclusions:1.Steaming pretreatment is a very powerful means to decrease defects induced by the drying processand increases the drying velocity of the lumber.2.The steaming—high一temperature drying schedule had resulted in fast drying and good quality ofthe dried lumber.     

紫椴小径材高温干燥工艺的研究

为了合理开发利用紫椴小径材,对其材性进行了研究,进而解决干燥工艺,提高干燥质量。通过研究小径材的构造和物理力学性能,并和成材作比较,研制高温干燥基准,提高紫椴小径材的干燥合格率。一、试材、试验设备及方法试材采自黑龙江省尚志县东北林业大学帽儿山林场,条件见表1。试验设备利用自行研制的间歇式电热真空干燥机,工艺试验共进行三次,每次均对试材进行质量统计,测试试材缺陷。选取5块试验板,3块含水率检验板,包括心材板、边材板、应力检验板各1块。检验板和试验板端头用铝箔纸封涂,检验板每4h称重一次。