Thedevelopment development hydraulic jack , the bearing heater , thebearing get up pulling out , the hydraulic pressure spanner , thehydraulic pressure pulls a horse , the hydraulic pressure small crane , nut broken cutting , the oil filter machine and the pipe bendingmachine and so on the advanced practical mechanical and electricalservice product has the world advanced level , the product and thetechnology widely applies to domain the and so on electric power , petrification , chemical industry , metallurgy , mine , spinning andweaving , papermaking machinery service department and the machinemanufacture unit , and in the daya bay nuclear power station , beijingsteel corporation , wuhan steel corporation , the baoshan steelcorporation , the daqing oil field , the victory oil field , the golmudoil field , the three gorges power plant , yangzi petrifies , qi and lupetrifies and so on in the national large and middle scale enterprisesand the project the comprehensive promoted use 研制开发的液压千斤顶，轴承加热器、轴承起拔器、液压扳手、液压拉马、液压小吊车、螺母破切器，滤油机和弯管机等先进实用的机电维修产品有世界先进水平，产品和技术广泛应用于电力、石化、化工、冶金、矿山、纺织、造纸等领域的机械维修部门和机械制造单位，并在大亚湾核电站、首钢、武钢、宝钢、大庆油田、胜利油田、格尔木油田、三峡电站、扬子石化、齐鲁石化等国家大中型企业和工程中全面推广使用。
Abstract : based on the basic concept of the revolving shell , the equation of the middle surface generatrix of the approximate ellipsoid portion of the ellipsoidal head is derived , the unwrapped area and the unwrapped diameter of the ellipsoidal head are calculated , the result is compared with that of derived from the real ellipsoid and that of calculated from the empirical equation , relative chart and code are given out , which could be used by manufactures for reference 文摘:根据回转壳体的基本概念，推导了椭圆封头的近似椭圆壳部分的中面母线方程，据此推导计算了椭圆封头的展开面积及展开圆直径，并根据椭圆壳几何形状推导的结果与经验公式所得结果进行了比较，给出了有关图表及计算程序，可供制造单位参考使用。
