马蹄形渐变管展开的数解法

Mathematical analytic method for the development of horseshoe convergent pipe

蜗壳是机组的主要部件之一，金属焊接蜗壳是由２０～３０节马蹄形渐变管组成，其上、下口是直径不等的两个圆（最后几节例外）。蜗壳的每一节，在下料时需要绘制展开图，采用数解法进行展开，即常用的坐标法或三角形法。对马蹄形渐变管的展开，文中提出卫套简单通用的解析公式。

Spiral case is one of main parts of generating unit. The welding metal spiral case is composed of 20～30 horseshoe convergent pipes which are two circles of upper and down mouth with different sizes (except last several pipes). When the material is prepared, each pipe is required to draw its developed map by using mathematics analysis, that is, common coordinate method and triangular method. For the development of horseshoe convergent pipe, this paper puts forward a set ofanalysis formula in easy and common use.