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选用离心泵机械密封时密封压力是需考虑的重要参数之一,密封工作转速是影响运转稳定性及密封端面磨损的重要因素,工作温度一般的机械密封都能适用。对在高温、低温下工作的机械密封,除了选择合适的辅助系统之外,还要充分考虑密封材料和结构。还可借助机械密封辅助系统,以不同的冲洗的方式达到冷却、润滑和过滤等目的,为机械密封可靠工作创造良好的环境。 相似文献
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在水泵的密封问题上,采用机械密封代替填料密封,彻底解决填料密封存在的缺点,提高了设备管理水平,降低了产品成本费用。 相似文献
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通过特殊的结构设计和力学计算,研制了一种能够在往复机械正常工作过程中,及时地、自动地保持对填料施加恒定压紧力的新型装置。应用实例是使用于潜艇某装置的填料压紧。 相似文献
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针对油气田勘探中,复杂的钻井工况导致动密封工作性能极不稳定的问题,结合单金属密封结构和井底高压环境,利用有限元方法对单金属密封受压情况下的接触压力进行分析。用雷诺方程计算单金属动密封的泄漏率,以减小最大接触压力和泄漏率为优化目标,利用正交试验和F评价方法对单金属密封结构参数进行优化,得到密封结构参数对密封面接触压力和泄漏率的影响情况,并将每个水平数对应的优化目标计算结果分别取平均值,得到不同水平影响下接触压力和泄露率平均值的变化趋势,从而确定密封结构的最优水平值,并借助有限元仿真对优化前后的密封性能进行对比。最后根据优化前后的密封结构参数加工2套密封试件,进行密封实验。仿真分析和实验结果表明:高压工况下优化前的密封面内侧磨损严重,钻井液颗粒容易侵入密封面;而优化后密封面的最大接触压力有所降低,动密封面的最高温度和泄漏率明显降低。研究结果对改进单金属密封的工作性能、提高井下动密封的可靠性有重要的现实意义。 相似文献
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野战装备封存封套材料研究 总被引:4,自引:11,他引:4
研发性能优异的封套材料是装备集合封存技术成败的关键.对封套材料的阻隔机理进行了系统分析,论证了封套材料的技术指标,提出了典型封套材料的结构设计. 相似文献
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低温真空泵作为一种高比抽气速率和极洁净的高真空泵,在很多科研和工业加工方面的应用越来越广泛。一般低温真空泵大多以G-M制冷机作为冷源。本文针对G-M制冷机中的二级密封作用进行了实验研究,结果表明:当温度下降到80 K以下区间,二级蓄热材料的热容发生转变,热容量变小,制冷量不足,从而影响到低温泵的极限制冷温度,二级密封的作用显著体现。 相似文献
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U seal components are widely used in light water reactor (LWR) plant for the purpose of sealing and connecting vessels and piping. Due to remarkable environmental effects, the environmental fatigue analysis is of crucial important for assessing the life of U seal in LWR applications. The environmental effects are incorporated by multiplying the cumulative fatigue usages (CUF) with an environmental factor (Fen), which is a complex function of many variables such as dissolved oxygen (DO) content, strain rate, temperature. The Fen-factor is found to be greater than 2 at the root of lower U seal branch, which indicates that environmental effects can significantly reduce the fatigue life of the components. Since the fatigue is related and initiated by high local stresses and temperature transient, an elastic–plastic finite element (FE) calculations are carried out. The environmentally assisted fatigue life assessments were performed by implementation of Fen-factor in FE calculation. The results of the case studies suggested that there were a sharp increase in calculated fatigue usage with Fen-factor, and the monitoring data were in consistent with the predicted environmental fatigue usage. 相似文献
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为了提高耐压腔室内引出导线在高压环境下密封的可靠性,保证井下工具内使用的电子设备能够在常压下工作,设计了一种注塑类高压密封连接器.使用有限元软件对内部填充材料为橡胶、环氧树脂时的连接器密封性能作了分析,并进行了实验验证.分析和实验结果显示:当填充材料为橡胶时,其密封性能较好,外壳体的半锥角取88°较为合适,但在高压作用下橡胶易被挤出;当填充材料为环氧树脂时,可避免材料挤出现象发生,但在一定密封压力范围内会出现液体泄漏;当2种材料组合使用时,随着环氧树脂比例的增加,填充材料的外凸距离减小,环氧树脂体积比为40%较为合理.高压密封连接器主要靠前5扣螺纹承载,最大应力出现在外壳体的第1扣螺纹与第2扣螺纹之间的小径处;插针的最大应力出现在橡胶与环氧树脂交界处偏上位置.研究成果对高压密封连接器的设计以及内部填充材料的选择具有一定的参考意义. 相似文献
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Function sharing is the simultaneous implementation of several functions by a single structural element. This article describes how the idea of function sharing can be used in a computational design procedure that produces efficient designs from modular designs. These ideas have been implemented as a computer program for the domain of mechanical devices that can be described functionally as a network of lumped-parameter idealized elements. 相似文献
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Stefano Farris Carlo Alessio Cozzolino Laura Introzzi Luciano Piergiovanni 《Packaging Technology and Science》2009,22(6):359-369
This paper presents the results of an investigation through the design of experiment technique regarding the influence of temperature, dwell time and bar pressure on the heat seal strength of oriented polypropylene films coated with a gelatin‐based thin layer. This chemometric approach allowed achieving a thorough understanding of the effect of each independent factor on the two different responses (maximum force and strain energy) considered in this work as a measure of the strength necessary to break the bond across the sealed interface. Surprisingly, the factor affecting both responses the most was the bar pressure rather than the sealing temperature. Moreover, whereas the bar pressure negatively affected the seal strength of coated polypropylene films, the sealing temperature had a positive effect. Dwell time did not have any significant influence as a main factor, while influencing negatively the seal strength as an interaction term (i.e. time × pressure), together with the further interaction temperature × pressure. The mathematical models obtained for the two responses provided different results in terms of fitting capability (R2) and prediction ability (Q2). In particular, for the maximum force response, R2 and Q2 were equal to 0.571 and 0.405, respectively, whereas the model supporting the strain energy response gave R2 = 0.932 and Q2 = 0.937, highlighting that for quantifying the seal strength, the energy necessary to break a seal is a better measure than the maximum force. The highest seal strength values obtained during this work were of 0.6615 N and 19.6 N·mm for maximum force and strain energy, respectively. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献