差速浮动式传输密封的泄漏分析

根据流体动静压润滑理论,结合差速浮动式传输密封的密封间隙的结构特点,分析转速、压力、间隙大小等参数变化对差速浮动式传输密封泄漏性能的影响。结果表明:差速浮动式传输密封的泄漏量与工作介质的黏度呈反比,因此,可通过控制工作温度来调节介质的黏度,从而控制泄漏量;密封泄漏量与动环转速的相关性较小,与密封间隙的相关性较大;工作负载波动将引起泄漏量的变化,且随着密封间隙的增大,泄漏量波动越明显。

差速浮动式传输密封腐蚀机理与防护措施

差速浮动式传输密封是推料式离心分离机上用来传递液压油压力,推动活塞杆往复运动的关键部件。因其恶劣的使用环境和特殊的结构,极易形成腐蚀而失效,其中以电化学腐蚀、应力腐蚀、端面磨蚀最为严重。根据现场观察和实物对比,在分析其腐蚀机理、条件、特征及发展的基础上,提出了缓解腐蚀发生的具体方法和措施,为解决和改善差速浮动式传输密封腐蚀问题提供参考。

差速浮动式传输密封性能分析

介绍一种新型的非接触式轴端机械密封——差速浮动式传输密封的工作原理及密封机制,根据流体力学的基本原理和静压气体润滑理论,建立传输密封泄漏量、压力分布、摩擦转矩、端面温升、承载能力和液膜刚度的计算公式。利用MATLAB软件对传输密封的性能进行数值模拟,分析密封结构参数和动力参数对密封性能的影响。分析结果表明,端面泄漏量的重要影响因素是端面间隙、液压油的压力波动和液压油的黏度,动环转速对泄漏流量的影响很小;密封间隙中主要以混合摩擦为主,且摩擦转矩与端面压力成正比,与密封间隙近似成反比例关系;密封间隙中的液膜刚度在初始液阻比为1时取最大值,且液膜刚度与端面压力成正比,与密封间隙成反比例关系。

基于变黏度条件下差速浮动式传输密封泄漏量的研究

对定黏度和变黏度条件下差速浮动式传输密封泄漏量进行了分析和计算,通过建立差速浮动式传输密封动平衡方程,采用迭代方法获得密封间隙出口处温度的收敛解,最终确定变黏度条件下密封间隙稳态时的泄漏量。并对不同转速、不同压力、定黏度和变黏度条件下密封间隙泄漏量变化规律进行数值分析。计算结果表明,在定黏度条件下转速对密封间隙的泄漏量几乎没有影响。在变黏度条件下密封间隙的泄漏量随着转速的增大而变大,低压力对油液黏度影响较小,高压力下油液黏度随压力增大而变小。

离心机差速浮动式传输密封结构设计

针对离心机差速浮动式传输密封在使用过程中出现的磨损加快、油温过高、泄漏量偏大、不易安装、使用寿命缩短等问题,根据传输密封使用工况,通过对传输密封进行输油通道的理论计算,确定输油通道的最小直径和动、静环上孔的个数;对输油流道结构进行加工优化,使动环的两斜孔对称并圆滑贯通,静环的斜孔与端面槽贯通均匀;提出采用高分子材料尼龙6与氟橡胶O形圈的组合密封,有限元分析结果表明,该组合密封圈的设计尺寸满足密封要求。设计的传输密封在推料式离心机上的使用结果表明,该产品质量稳定、运行可靠、使用周期长,可完全取代进口传输密封。

差速浮动式传输密封装置温度场的分析

差速浮动式传输密封是一种新型的密封装置,在制浆造纸机械设备中有较为广泛的应用。通过热平衡分析和模型简化,建立了差速浮动式传输密封二维稳态柱坐标下无内热源的固体导热微分方程;并应用ANSYS软件建立差速浮动式传输密封动、静环温度场有限元分析模型,对密封环温度场进行求解,获得了动、静环的温度分布规律。分析结果表明:动、静环在两个密封端面处均产生高温,且具有较大的温度梯度,动、静环最高温度都出现在密封面II处;且动、静环的温度及梯度变化在规定范围内,密封的结构设计合理。

Transfer of Ultrafine Particles and Air in Multi-storey Buildings

An emerging issue in Denmark is passive smoking in residential buildings where non-smokers are exposed to smoke from their neighbours. There are various ways that smoke is transferred from one flat to another. The air transfer rate between two flats in a multi-storey building depends on its construction, tightness and age. This paper presents results of a study on the transfer of ultrafine particles and tracer gas in an older multi-storey building in Copenhagen. The aim of the study was to quantify the transfer ofultrafine particles and gases from one flat to another fiat before and after sealing the floor. A new floor-sealing method was applied to seal the floor between the two flats. The sealing method was developed by a firm specialising in sealing. Indoor ultrafine particle concentrations and tracer gas were measured continuously in the two fiats during the measuring periods. In the unoccupied fiat, the gas source was N20 and the particle source was burning cigarettes. Reduction of the concentration of ultrafine particles and tracer gas by sealing the floor with polyethylene and joint filler made of bitumen was studied. It was evaluated how the sealing performed with regard to decreasing the amount of ultrafine particles and a tracer gas transferred between two fiats separated by a floor. When the floor between the flats was not sealed, the results showed that about 4% of the ultraflne particles and 14% of the tracer gas were transferred. After sealing, the amount transferred was reduced to 1.6% and 5%, respectively.