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介绍了一种大型球阀机械密封锁定螺栓拧紧与松卸的自动化改造设计方案。大型球阀广泛用于水力发电厂发电机组叶轮蜗壳前端。叶轮检修时需将球阀关闭,同时对阀体内部机械密封。均布于法兰盘上连接螺栓内侧的三十个螺栓拧紧时对球阀密封,松卸至规定位置时解封。设计采用三轴拧紧机变矩拧紧方案解决球阀机械密封螺栓的自动化投退问题,设备由转动轨道装置、拧紧机、自动控制系统构成,具有自动定位、自动套进螺栓、扭矩值及行程自动控制功能。拧紧及松卸的质量可靠,提高了生产效率,避免了工人高空作业。 相似文献
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付叶轮动力密封和停车密封装置可以克服填料和机械密封的某些不足,具有结构简单、密封可靠、点液不漏的优点,目前已在冶金矿山和石油化工行业中得到较普遍的应用。付叶轮动力密封付叶轮动力密封(又叫离心密封、流体动力密封等)可分为付叶片密封(图1)和付叶轮密封。当泵转动时,叶轮就产生压力为P_出 相似文献
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利用离心泵叶轮切割理论降低泵的扬程,利用流体节流降压原理改善泵的机械密封运行环境,延长机械密封寿命。根据现场实际情况,通过分析找到改造办法,使闲置设备得以再次利用,泵的机封使用寿命得到提升,降低了出口压力后,保证了压滤机的安全稳定运行。 相似文献
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一、前言副叶轮密封是一种转轴密封结构,也称流体动力密封,其作用原理是依靠两只密封叶轮(主叶轮带背叶片和副叶轮),在旋转时产生逆压来阻止介质的泄漏。优点是: (1)运转时无泄漏,不存在机械相互磨损,密封件使用寿命长;(2)平衡轴向力,降低静密封处的压力,减少泵壳与叶轮的磨损,(3)适应于许多苛刻条件下的介质密封,如密封溶融硫酸 相似文献
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离心泵叶轮轴向力自动平衡新方法 总被引:7,自引:0,他引:7
介绍了一种创新的离心泵结构,对离心泵叶轮按斜流式叶轮设计,同时采取叶轮进口端面密封及叶轮在泵轴上浮动等措施,实现离心泵叶轮上的轴向力自动平衡。对实现轴向力自动平衡的关键问题进行了深入分析,即当叶轮进口的端面密封处于紧密接触密封状态时,可以使轴向力的方向指向叶轮后盖板,推开密封端面,使叶轮轴向力自动平衡。推导出能够满足轴向力自动平衡的叶轮几何尺寸间的关系不等式,并给出具体算例进行了验证。另外,进行了进口端面密封设计、推力轴承设计,讨论了影响水泵效率的相关因素。 相似文献
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Particle Image Velocimetry (PIV) and Laser Doppler Velocimetry (LDV) are used to measure the three components of the flow velocity in the seal chamber of a mechanical pusher seal at three shaft rotational speeds of 1000, 1800, and 3600 rpm. The flow details in the narrow gap region between the rotor and the stator are also measured. The Taylor numbers corresponding to the three rotational speeds with water and a lightweight heat transfer mineral oil used as process fluids varied between 1.087 × 107 and 9.48 × 1010. A smaller size impeller with diameter 12.7 cm compared with 25.4 cm diameter impeller used in previous works, was used in this research. Large differences are observed between flow structures in the seal chamber flow for oil and water. The effect of impeller size and the location of balance holes on the seal chamber flow for water at rotational speed of 1800 rpm is presented 相似文献
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A modeling methodology of pump impeller shroud and wear-ring seal as a whole has been developed to give its rotordynamic coefficients. In this work the governing equations are derived for the continuous flow path of the impeller shroud and wear-ring seal. Pressure loss at the discontinuity of the connecting point between the impeller shroud and the wear-ring seal is defined by utilizing a pressure loss coefficient obtained from experimental measurements. The governing equations are solved directly by using the known conditions at the inlet of the impeller shroud and the outlet of the wear-ring seal. A detailed rotordynamic analysis has been carried out on a 750 m-head fourteen-stage centrifugal pump system with the effects of the hydrodynamic forces of such as impeller shroud and wear-ring seals, balance piston, and interstage seals. Results have shown that the first critical speed obtained with all the seal effects is much higher than that obtained without those effects, and moreover that the system under consideration is unstable. Large cross coupled stiffness (k) of the impeller shroud and wear-ring seal has been suspected as the source of the problem. Design modifications of the impeller shroud and wear-ring seal geometry have been performed to decrease k and increase the direct damping(C). Finally, the design modifications have yielded a stable and well damped system. 相似文献
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阐述了适合于输送易汽化介质的小流量高扬程高速离心泵的研制方案和结构设计特点,采用以效率为目标函数的优化水力设计方法,并采用开式叶轮或复合叶轮及双密封结构,保证了泵机组具有优越的性能指标和密封可靠性。 相似文献
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为探究基于叶轮转子系统下干气密封轴向振动特性,基于干气密封结构特性,建立叶轮转子-轴承-干气密封系统轴向振动模型,采用待定系数法进行求解,推导得出静环轴向振动幅值表达式;建立叶轮转子-轴承-干气密封系统几何模型,运用ANSYS Workbench软件进行模拟仿真计算,分析气膜刚度和激振力对轴向振动的影响。结果表明:气膜刚度对动、静环振动幅值的影响不大;动、静环振动频率相同、振动幅值相同,说明动、静环的追随性高,其间隙稳定,从而保证干气密封的稳定运行;动、静环位振动幅值与激振力成正比关系,说明激振力严重影响干气密封的稳定性,为提高干气密封的稳定性,应平衡好叶轮的轴向激振力。 相似文献
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某石化公司20万吨/年高压聚乙烯装置在开工初期,两台大功率热水泵均出现了在灌泵时离心泵抱轴和进口管线剧烈振动的现象,造成了大功率热水泵无法正常启动,通过改变泵启动时的操作方法及加大叶轮密封环与壳体密封环之间间隙的方法,成功地解决了大功率热水泵启动的问题,至今已经运转了40个月,效果良好. 相似文献
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