三板点焊焊接工艺改进

随着现代泵技术的不断发展，用户对泵的性能要求越来越细化，小流量、高扬程的离心泵 在消防、锅炉给水等方面得以广泛应用，以往泵的主要零件均为铸造，体积较大，由于不锈 钢薄板冲压技术在现代泵中的应用，使之变得轻巧、紧凑。1 叶轮的组成及要求图1为水泵主要零件叶轮，通常叶轮为整体铸造，但由于此类小流量泵叶轮叶片出口宽度 较窄，只有2.5 mm，铸造较为困难，现采用1 mm厚1Cr18Ni9Ti不锈钢薄板冲压成形，将叶轮 分为叶轮前盖板1件、叶轮叶片6件和叶轮后盖板1件3部分冲压后用焊接工装组合后在点焊机 上焊接。焊接后的零件与铸件相…     

On the joint distribution of surface slopes for the fourth order nonlinear random sea waves

Based upon the nonlinear model of Longuet-Higgins the joint distribution of wave surface slopes is theoretically investigated. It is shown that in the fourth order approximation, the distribution is given by truncated Gram-Charlier series. The types of wave-wave coupling interactions are related to the order of approximation to nonlinearity of sea surface, which eventually defines the truncated term of the Gram-Charlier series. For each order approximation, the coefficients in the series are modified comparatively to the corresponding ones for the previous order approximation. If the nonlinear effect of the kurtosis is considered, the wave surface must be as accurate at least as to the third order approximation, and with regard to skewness, the wave surface must be as accurate at least as to the fourth order approximation.     

DG型高压锅炉给水泵轴承体密封的改进

DG型高压锅炉给水泵目前在电厂中还育相当数量在使用。DG型高压锅炉给水泵的滑动轴承采取强制润滑，因此对轴承体两侧的密封性能要求较高，但原泵的结构设计在现场使用效果并不理想，漏油现象较为普遍。在电厂日益注重环境和安全的今天，解决好漏油问题对给水泵生产厂家提高产品在电厂用泵市场的竞争能力十分重要。