求翻译：6、涡壳形状。开发初期，涡壳形状较简单，也不尽科学。如有的采用分体焊接风道，有的采用风道上部与上壳以泡沫塑料密封，结构简陋，普遍存在漏油现象。后来逐步改进，采用了双曲线风道，有的采用独立双风道，整体封闭。现在的深箱型单电机涡壳密封性均较好，也利于油烟的排除，重点厂家的涡壳已解决了漏油问题。是什么意思？

6, volute shape. Early development, volute shape is relatively simple, are not scientific. If the use of split welded duct, and some use the duct to the Ministry and the foam seal on the shell, structure simple, the prevalence of leakage. Then gradually improved, with a hyperbolic duct, and some use

6, turbo-shell shapes. early stages of development, volute casing shape is relatively simple, is also not scientific. If any of the sub-welding totalling 28.35 totalling 28.35 used the upper part, there is currently a foam with the flimsiness sealed, oil spills, pervasive phenomenon. Step-by-step im

6th, wo shell shape.The development initial period, wo the shell shape is simple, also endless science.If some use fission welding air flue, on some use air flue and on the shell by the foam plastics seal, the structure is crude, has the oil leak phenomenon generally.Afterwards improved gradually, h

Vortex 6, shell shape. The initial stage, volute shape is relatively simple, is also not the science. If existing uses welding duct, duct of shells with foam on the top and seal is used, the structure simple, the prevalence of oil leakage. Then gradually improved, using a double-curved duct, while o

6, volute shape. Early development, volute shape is relatively simple, are not scientific. If the use of split welded duct, and some use the duct to the Ministry and the foam seal on the shell, structure simple, the prevalence of leakage. Then gradually improved, with a hyperbolic duct, and some use