Orifice size is designated by the letter D through R and is determined by ASME standards. (Use the saturated steam capacity charts provided in this guide to determine the orifice size.

• ASME标准规定，节流孔通径由字母D至R来表示。(采用所本指南提供的饱和蒸汽流容表来选择节流孔通径。