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弹簧预紧力可调式振动深松机设计与试验 总被引:2,自引:0,他引:2
为了减小深松机的耕作阻力和拖拉机的动力消耗,增强深松机对不同类型土壤的适用性,设计了弹簧预紧力可调式自激振动深松机。在机具工作过程中,通过自激振动单元的振动作用,可有效减小深松机的牵引阻力;通过弹簧预紧力调节机构可改变弹簧的预紧力,以适应不同物理特性的土壤,获得理想的深松效果。田间试验表明在保证耕深的前提下,合适的弹簧预紧力可有效减小机具的耕作阻力。为了测试该深松机的减阻性能,设计了2.5、3.2、4.0km/h 3种作业速度和250、300、350mm 3种深松深度,进行了两因素三水平的全因素试验,试验结果表明:在不同作业速度与深松深度下,与非振动深松机相比,该深松机均能有效减小牵引阻力,减阻比为10.30%~22.65%;对不同作业速度和深松深度下的振动深松牵引阻力和非振动牵引阻力进行了方差分析。结果表明作业速度、耕作深度和机具类型对深公机工作阻力均有显著性影响,在不同作业速度下,由于自激振动单元的减阻作用,随着耕作深度的增加,振动深松牵引阻力增加速度小于非振动深松。 相似文献
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振动深松机的研究设计 总被引:1,自引:0,他引:1
借鉴同内外先进技术,结合我国实际情况,利用偏心块旋转产生的离心力使深松铲产生振动,研发出一种振动式深松机.介绍振动式深松机的基本原理、总体结构及重要参数的选定方法.该机与普通深松机相比,在同等结构质量及作业条件下,能够大大减少整个机组的牵引阻力.降低能源消耗,提高深松作业质量. 相似文献
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辽宁玉米收获机械化发展现状与对策 总被引:1,自引:0,他引:1
借鉴同内外先进技术,结合我国实际情况,利用偏心块旋转产生的离心力使深松铲产生振动,研发出一种振动式深松机.介绍振动式深松机的基本原理、总体结构及重要参数的选定方法.该机与普通深松机相比,在同等结构质量及作业条件下,能够大大减少整个机组的牵引阻力.降低能源消耗,提高深松作业质量. 相似文献
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土壤环境是农业发展的重要基础条件,是一种宝贵的不可再生资源。长期以来,由于农业机械的反复碾压和土壤过度开发,导致土壤紧实,破坏土壤耕层,影响作物的生长与产量提升。深松是指利用深松机械疏松土壤、改善紧实度,是提高土壤蓄水保墒能力的有效方式。传统深松机存在作业阻力大和工作效率低等问题。因此,设计一种振动深松机,基于振动深松机减阻机理提出整体设计方案,并对关键部件进行设计与选型,最后通过田间试验验证振动深松机对土壤环境的改善作用。 相似文献
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机械化土壤深松技术,一般是指超过正常犁耕深度的松土作业,土壤通过深松可形成“天然土壤水库”。深松作业时,土壤只松不翻,可保持上下土层不乱;深松对地表覆盖破坏小,能减少土壤水分的散失,防止风蚀水蚀,利于保墒。深松作业机械有全方位深松机、凿式深松机、V型深松机、鼠道式深松机、振动式深松机等。 相似文献
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随着农业机械化的快速发展与应用,农业机械长期碾压、翻耕,破坏了土壤犁底层,使犁底层变得硬、厚、肥力降低,限制了作物产量提高与品质提升。深松机械可以改善土壤肥力、打破犁底层,为作物生长提供一个良好的土壤环境,但是目前深松机械存在田间阻力较大、机械能耗高等问题。自激振动式深松机主要是基于弹簧片使深松铲发生振动,土壤在不同频率和不同振幅下破碎,提高土壤深松效率与深松稳定性。系统论述了国内外振动深松机发展现状,对自激振动式深松机的振动弹簧、深松铲等关键部件进行设计。研究结果可以为深松机械的发展与设计优化提供参考和借鉴。 相似文献
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感官检验棉花的品级,这是农村常见的一种检测手段.它的一个主要特点就是存在不确定性.这是由于检验员的品级检验水平存在一定的差异,其中有很多因素制约着检验的结果.文章对影响感官检验结果的因素进行了系统的分析. 相似文献
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《Journal of Agricultural Engineering Research》1998,69(3):249-254
A model to represent the discolouration of dried powder of carrots as a function of temperature was developed. Two types of carrots, Asian and European, containing large amount of lycopene and β-carotene, respectively, were tested. The dried powder was stored under an atmosphere with O2and at three different temperatures, 5,20 and 35°C. The surface colour of the powder was monitored during storage by a Hunter colour ratioa/b. In the proposed model, the rate of oxidation was assumed to be represented by the product of the fraction of concentration of oxidized pigment at arbitrary time and a specific rate of oxidation of pigment. The rate parameters in the proposed model were calculated by fitting the experimental data with smooth curves by trial and error at the end of the induction period but before discolouration took place. The frequency constant and activation energy, expressing the temperature dependence of the rate parameters, were expressed by the Arrhenius relation. The simulation results of a Hunter colour ratioa/bof dried powder at 25°C showed good agreement with the experimental data, suggesting that the proposed model was effective for the prediction of discolouration of dried powder of both types of carrot. The use of the induction period in the manner described may enable the shelf life of dried powder to be predicted. 相似文献
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从灾害经济学的角度探讨了城镇供水优化调度的必要性和可能性,认为在缺水不可避免的情况下,对供水进行优化调度可以减小缺水带来的损失,产生较好的减灾效益,特别是可以大大减小严重干旱的灾害效应。并根据水资源的特性,提出了缺水损失的计算模式以及优化调度的原则和方法。 相似文献
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The fractional outflow rate of water from the rumen, measured as the rate of disappearance of the chromium complex of ethylenediamine tetra-acetic acid, was related to a number of dietary factors. A multiple regression equation was derived which expressed fractional outflow rate as a function of the intakes of dry matter, ash, acid-detergent fibre and crude protein.The data analysed consisted of 243 observations for sheep on 59 diets, including forage, concentrate and mixed diets. The ranges covered by the data were: fractional outflow rate 0.7–3.6 day?1; dry matter intake 560–1400g/day; ash 4–30%, acid-detergent fibre 7–41%, crude protein 5–26 % of dry matter; there were no observations for sheep of less than 34 kg liveweight.The equation accounted for 56·3 % of the total variance. Between-sheep variance could not be calculated for the whole of the data but was undoubtedly substantial since, for a sixth of the data, it was known to account for 38 % of the total variance. 相似文献