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综合分析了管材定径的基本方法和各自的特点,结合分析提出一种适合高速生产的冷却定径装置。对高速生产条件下定径套的参数作了研究,得出当定径套长度为管材外径的2.5倍时最适合管材高速生产;锥度值a=10"~20"最有利于管坯送入定径套和在管材外表面和定径套内壁间水膜的形成,达到最大生产线速度。 相似文献
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无规共聚聚丙烯管材挤出设备的设计 总被引:1,自引:0,他引:1
根据无规共聚聚丙烯(PP-R)管材生产的特点,指出采用普通挤出设备无法满足生产要求,必须安装PP-R管材生产线,并对挤出机的螺杆与机筒,管材模具,定径冷却系统进行专门设计,生产初中表明,挤出螺杆应设有特珠的混炼段,机筒采用衬套结构;挤出机头宜采用过滤式,并用水帘式定径套进行冷却定径,通过对挤出设备的设计和生产工艺的控制,可实现高速高效生产优质PP-R管材。 相似文献
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本文通过对挤出机定径装置的结构分析,论述了定径装置对于制品的截面形状、尺寸和光洁度等影响,以及挤出机今后的发展方向。 相似文献
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从原料、设备、工艺等方面介绍塑料管材和板材挤出成型的基本原理和方法。重点介绍管材和板材的种类,主要应用领域和范围;挤出设备的组成和特点,管材机头和板材办头的工艺要求和结构特点,冷却定型和定径的方法,列举了几种常见的管材冷却方法,给出了常见塑料管材和板材的参考加工温度。并对特殊性能和结构的管材挤出和板材挤出进行了简单介绍。 相似文献
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《现代塑料加工应用》2016,(6)
对5种无规共聚聚丙烯(PPR)管材专用料进行管材挤出试验,确定了影响PPR管材制样成功率的因素。分析了定径套对PPR管材制样过程中口模膨胀的影响,并对定径套的内径及挡水环水路进行改造。改进后,口模膨胀现象明显降低。 相似文献
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通过对水喷泵系统工作原理进行分析 ,推导了水泵的工作状态参数与设备真空度的关系 ,研究了水泵的流量与压力对设备真空度的影响。指出使水泵的额定流量与水 气射流泵的水流量相匹配将有效地提高水喷泵系统的工作效率。 相似文献
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Post-annealed gallium and aluminum co-doped zinc oxide films applied in organic photovoltaic devices
Shang-Chou Chang 《Nanoscale research letters》2014,9(1):562
Gallium and aluminum co-doped zinc oxide (GAZO) films were produced by magnetron sputtering. The GAZO films were post-annealed in either vacuum or hydrogen microwave plasma. Vacuum- and hydrogen microwave plasma-annealed GAZO films show different surface morphologies and lattice structures. The surface roughness and the spacing between adjacent (002) planes decrease; grain growth occurs for the GAZO films after vacuum annealing. The surface roughness increases and nanocrystals are grown for the GAZO films after hydrogen microwave plasma annealing. Both vacuum and hydrogen microwave plasma annealing can improve the electrical and optical properties of GAZO films. Hydrogen microwave plasma annealing improves more than vacuum annealing does for GAZO films. An electrical resistivity of 4.7 × 10−4 Ω-cm and average optical transmittance in the visible range from 400 to 800 nm of 95% can be obtained for the GAZO films after hydrogen microwave plasma annealing. Hybrid organic photovoltaic (OPV) devices were fabricated on the as-deposited, vacuum-annealed, and hydrogen microwave plasma-annealed GAZO-coated glass substrates. The active layer consisted of blended poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) in the OPV devices. The power conversion efficiency of the OPV devices is 1.22% for the hydrogen microwave plasma-annealed GAZO films, which is nearly two times higher compared with that for the as-deposited GAZO films. 相似文献
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综述了二种高压浸渍真空系统的配置、工艺过程、特点及其对浸渍效果的影响。实际测试结果表明:在对浸渍罐进行抽真空作业同时合理地将浸渍沥青注入浸渍罐,减小由于向浸渍罐注入浸渍沥青时真空度受破坏的程度,从而提高产品浸渍效果。 相似文献
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AbstractVacuum drying is one of the most effective methods to protect submarine natural gas pipes from blockage caused by hydrate and internal corrosion. This article presents a model for analyzing the mass, momentum, and energy transfer processes in pipeline drying with vacuum drying method. Model of the evaporation rate of liquid water is derived from Hertz–Knudsen–Schrage equation. Finite volume method is employed to discretize the governing equations with an upwind implicit scheme in present work, and 2nd order upwind scheme for energy equation is adopted to weaken numerical dissipation. Non-linear algebraic equations after discretization are solved by Newton-Raphson method. Reliability and accuracy of this model are validated via three experimental cases. Numerical results coincide well with the experimental data, and the relative errors of the calculated drying time are 1.7% in Case 1, 1.2% in Case 2, and 5.5% in Case 3. Finally, the dynamic characteristics of the vacuum drying process are analyzed such as dynamic distributions of pressure, temperature, mass flow rate, and liquid holdup. Mathematical model and algorithm developed in present work provide understanding and insights of the vacuum drying process, which aids in determining cost-effective pipeline drying scheme. 相似文献
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报道了液环式真空泵在煤焦油常减压蒸馏工艺中的应用.介绍了真空泵的分类,真空泵的选型,真空系统及其控制参数,重点讨论了在生产运行过程中影响真空度的因素和处理办法,并结合生产实际就技术改进提出了合理化建议. 相似文献
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