"Salmon," notes writer Susan Ewing in The Great Alaska Nature Factbook, "pump through Alaska like blood through a heart, bringing rhythmic, circulating nourishment to land, animals and people".
This paper states the method of selecting and using circulatingpump in hot water heating system properly to save electric energy.
合理的选择和使用热水供暖系统循环水泵,以达到节约电能的目的。
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There were some new problems such as the easy exhaustion of the liquid ammonia circulatingpump and the appearance of liquid ammonia product was off specification.