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软填料密封存在的问题与改进 总被引:1,自引:0,他引:1
针对传统软填料密封的基本结构及密封原理。分析了软填料密封存在的问题,提出了从提高密封填料性能和改进密封结构来改善密封效果和提高使用寿命的几种措施。 相似文献
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水轮机主轴密封的改进 总被引:2,自引:0,他引:2
针对水轮机主轴密封采用传统的盘根密封存在的不足之处,通过对反螺旋式密封、离心式密封原理、结构特点分析,确定了水轮机主轴最佳密封方式为离心式密封。 相似文献
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充气式密封装置的结构与特点 总被引:1,自引:0,他引:1
充气式密封装置的结构与特点中船总第七一○研究所(443003)高频卢刚叶定奇杨玉田本文将介绍几种已成功地解决了大间隙、长周边的静压密封和轴向往复运动的大行程大活塞面密封的充气式密封装置,现就其结构、原理及特点等总结如下,以供设计人员参考。1静压密封1... 相似文献
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针对离心式水泵填料密封存在的缺陷,将其改造为迷宫衬套及油封密封结构,有效地改进了离心泵的密封结构,取得了良好的密封效果,提高了工作效率和经济效益。 相似文献
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装筑和道路机械旋转轴应用最广的接触密封,是用橡胶和其它薄片材料制成的皮碗密封。它的优点是密封性能好,结构简单,外形尺寸小,重量轻,造价低,易装配。标准的密封则不能完全满足这些要求。因此,世界上主要的发达国家正理论上和实践中进行了大量的研究,在此基础上设计出用优良性能的材料制造的弹性皮碗密封的新结构。文献中所研究的一些皮碗密封结构如下。Ta让oKogyoCoLtd(日本)设计的用于旋转轴的皮碗密封。它装配方便,密封良好。密封由金属骨架圈4组成(图1)。该围由薄片材料制造,其有凹槽的箱形用来支承带唇口的密封3和压… 相似文献
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Compared with traditional mechanical seals,magnetic fluid seals have unique characters of high airtightness,minimal friction torque requirements,pollution-free and long life-span,widely used in vacuum robots.With the rapid development of Integrate Circuit(IC),there is a stringent requirement for sealing wafer-handling robots when working in a vacuum environment.The parameters of magnetic fluid seals structure is very important in the vacuum robot design.This paper gives a magnetic fluid seal device for the robot.Firstly,the seal differential pressure formulas of magnetic fluid seal are deduced according to the theory of ferrohydrodynamics,which indicate that the magnetic field gradient in the sealing gap determines the seal capacity of magnetic fluid seal.Secondly,the magnetic analysis model of twin-shaft magnetic fluid seals structure is established.By analyzing the magnetic field distribution of dual magnetic fluid seal,the optimal value ranges of important parameters,including parameters of the permanent magnetic ring,the magnetic pole tooth,the outer shaft,the outer shaft sleeve and the axial relative position of two permanent magnetic rings,which affect the seal differential pressure,are obtained.A wafer-handling robot equipped with coaxial twin-shaft magnetic fluid rotary seals and bellows seal is devised and an optimized twin-shaft magnetic fluid seals experimental platform is built.Test result shows that when the speed of the two rotational shafts ranges from 0-500 r/min,the maximum burst pressure is about 0.24 MPa.Magnetic fluid rotary seals can provide satisfactory performance in the application of wafer-handling robot.The proposed coaxial twin-shaft magnetic fluid rotary seal provides the instruction to design high-speed vacuum robot. 相似文献
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Although the leakage flow through labyrinth seals under stationary conditions has been examined by many investigators a reliable prediction of the effect of various labyrinth parameters on leakage rate has not been reported so far. The theoretical models for the seals proposed in most of the previous literature provided results with considerable differences and contradictions in some cases. The structure of the laminar incompressible flow and the performance of a number of seals of various shapes for both stationary and rotating conditions are investigated in this paper. The theoretical treatment is based on the formulation of three-dimensional axisymmetric momentum and continuity equations for labyrinth shapes having small height to radius ratio as is always the case in turbomachinery, rotodynamic pumps and many hydraulic devices. It is found in this paper that shaft rotation is only beneficial for the up-the-step seal, has no effect on grooved shaft and grooved casing seals and has an adverse effect on the down-the-step seal. It is also found that the use of a smaller clearance size at the entrance makes some improvement in the performance of the grooved shaft and down-the-step seals depending on the value of the height to width ratio of the seal. 相似文献
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推导了大型水泵油润滑导轴承梳齿迷宫密封泄漏量计算公式。通过实例计算了梳齿迷宫密封的泄漏量及各密封段的压降,分析了各段对密封效果的影响。比较了梳齿迷宫密封与端面密封的密封效果,分析了油润滑导轴承浸水的可能原因,指出了梳齿迷宫密封的适用性。结果表明:在水泵导轴承梳齿迷宫密封中O形密封圈的磨损量对泄漏量影响很大,O形密封圈必须选用耐磨性能好的材料,并控制泵轴摆度以减小O形密封圈的磨损量;在正常运行情况下梳齿迷宫密封的泄漏量远大于端面密封,因此要保证足够的排漏水能力,以免因排漏水不畅造成导轴承浸水。 相似文献
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Mechanical shaft seals used in pumps are critically important to the safe operation of the paper, pulp, and chemical process industry, as well as petroleum and nuclear power plants. Specifically, these seals prevent the leakage of toxic gases and hazardous chemicals to the environment and final products from the rotating equipment used in manufacturing processes. Diamond coatings have the potential to provide negligible wear, ultralow friction, and high corrosion resistance for the sliding surfaces of mechanical seals, because diamond exhibits outstanding tribological, physical, and chemical properties. However, diamond coatings produced by conventional chemical vapor deposition (CVD) exhibit high surface roughness (Ra ≥ 1 μm), which results in high wear of the seal counterface, leading to premature seal failure. To avoid this problem, we have developed an ultrananocrystalline diamond (UNCD) film formed by a unique CH4/Ar microwave plasma CVD method. This method yields extremely smooth diamond coatings with surface roughness Ra = 20–30 nm and an average grain size of 2–5 nm. We report the results of a systematic test program involving uncoated and UNCD-coated SiC shaft seals. Results confirmed that the UNCD-coated seals exhibited neither measurable wear nor any leakage during long-duration tests that took 21 days to complete. In addition, the UNCD coatings reduced the frictional torque for seal rotation by five to six times compared with the uncoated seals. This work promises to lead to rotating shaft seals with much improved service life, reduced maintenance cost, reduced leakage of environmentally hazardous materials, and increased energy savings. This technology may also have many other tribological applications involving rolling or sliding contacts. 相似文献
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The film formation in lip seals, due to the non-Newtonian rheology of the lubricant, has been a topic of speculation. Earlier work suggests that normal stresses in grease would be favorable for the film buildup between the seal lip and shaft or bearing ring. In the current article, we evaluate this earlier work and our earlier theoretical seal lip model with a series of experiments. We use a modified concentric cylinder geometry and a model fluid to study the fluid pressure distribution in the seal-type geometry. The results are then related to grease-lubricated seals and our earlier theoretical predictions. The present analysis shows that this earlier work and our earlier predictions are not correct and indicate that normal stresses in the grease pull the seal lip toward the shaft, increasing the contact pressure. However, normal stresses also ensure the presence of grease on the shaft or bearing inner ring, which enhances replenishment of the sealing contact. 相似文献