The hand hole cover shall be constructed of the same material as the pump casing and shall have surfaces which match the internal casing contours to minimize turbulence and localized wear.

• 探孔罩盖结构材料应该与泵壳完全相同,其表面应该与泵壳内部轮廓线相匹配,以减少由于扰动和定位造成的磨损。