化工离心泵采用变频调速技术的效果

化工过程中液体流量通常是通过离心泵出品阀的开度来调节的,能耗大。介绍交流电动机采用变频调速器的原理和优点,正确选择变频调速 容量的方法和接线要点,指出在交液电动机上安装变频调速器,以调节离心泵的转速来调节液体流量,节能效果显著,易实现自动控制,对电网容量的要求低,必将在化工过程中得到推广应用。     

串联泵输油工艺在华锦集团输油管道上的应用

结合中国兵器华锦集团储运工程项目,对原油长输管道中泵站的串联泵和并联泵输油工艺进行了综合比较,优化出串联泵输油工艺方案,并对串联输油泵系统的压力调节、安全保护系统等工艺技术进行简要介绍.     

离心泵调速时流量和扬程的曲线回归分析

以离心泵变频调节时的实测数据为基础,采用数理统计的方法,得到了离心泵的转速关于其流量和扬程的非线性回归方程,并检验证明了方程的有效性。     

大型离心式空压机组长周期运行探讨

针对某空压站空气压缩机组在实际运行过程中出现的异常情况,分析了温度、叶轮结垢、叶轮磨损和中间冷却器堵塞等因素对空压机组运行的影响,提出了合理可靠的运行参数、控制方法和改进措施。运行验证表明,这些解决方案可以有效地提高空压机组的运行水平和长周期运行能力。     

高压液氨泵并联运行流量脉动分析

通过对往复泵运动规律的分析,给出双泵并联运行累加流量和流量不均匀系数的计算公式,并利用Excel函数编程,对高压液氨泵并联运行累加流量进行模拟,探讨双泵并联运行在不同错相位角和转速下流量不均匀系数的变化规律,总结最佳操作工况,提出峰值分散技术应用的思路。     

离心泵与滑片泵流量脉动特性及串联实验研究

对离心泵和滑片泵的流量脉动特性进行研究,探讨两泵串联运行的可行性。然后建立以离心泵为前级泵、滑片泵为后级泵的串联实验平台,通过改变串联中间管路阻力和滑片泵的出口管路阻力对滑片泵的运行特性进行实验研究,实验结果表明:泵与管路所构成的系统流量小于或接近滑片泵的理论流量时,系统才能正常工作,否则会造成整个系统的流量和压力脉动;不可改变串联中间管路阻力,以免滑片泵偏离正常工作状态;可通过改变滑片泵的出口管路阻力调整泵和系统运行参数。     

Computer Simulations of Diffraction Effects due to Stacking Faults in β-SiC: II, Experimental Verification

Earlier results from computer simulation studies suggest a correlation between the spatial distribution of stacking errors in the β-SiC structure and features observed in XRD patterns of the material. Reported here are experimental results obtained from two types of nominally β-SiC specimens, which yield distinct XRD data. These samples were analyzed using high-resolution transmission electron microscopy (HRTEM) and the stacking error distribution was directly determined. The HRTEM results compare well to those deduced by matching the XRD data with simulated spectra, confirming the hypothesis that the XRD data are indicative not only of the presence and density of stacking errors, but also that it can yield information regarding their distribution. Moreover, the stacking error population in both specimens is related to their synthesis conditions, and is similar to the relation developed by others to explain the formation of the corresponding polytypes.