안녕하세요. API610를 보다가 이해가 되지 않는 부분이 있어서 문의드립니다.
API STANDARD 610 / 5 Basic Design
5.1.6 Pumps shall be capable of at least a 5% head increase at rated conditions by replacement of the impeller(s) with one(s) of larger diameter or different hydraulic design, variable-speed capability or use of a blank stage.
라고 표현되어 있는데 의미는 future revamping을 위해서 impeller size를 증가시킬 margin이 필요하다는 의미같은데 head increase등 정확한 의미는 무엇인지 궁금합니다
5.1.13 Pumps that have stable head/flowrate curves(continuous head rise to shutoff) are preferred for all applications and are required if parallel operation is specified. If parallel operation is specified, the head rise from rated point to shutoff shall be at least 10%.
Head rise등 정확한 의미 설명부탁드립니다.
감사합니다.
